Natl Toxicol Program Tech Rep Ser, 1988 Mar, 329, 1 - 176 NTP Toxicology and Carcinogenesis Studies of 1,2-Epoxybutane (CAS No . 106-88-7) in F344/N Rats and B6C3F1 Mice (Inhalation Studies); National Toxicology Program ; 1,2-Epoxybutane was selected for study because it is a short-chain epoxide that had been shown to be mutagenic and because no carcinogenicity data were available . Approximately 8 million pounds of 1,2-epoxybutane are produced annually in the United States . The chemical is used primarily as a stabilizer in chlorinated hydrocarbon solvents . Single-Exposure, Fourteen-Day, and Thirteen-Week Studies: Single-exposure, 14-day, 13-week, and 2-year studies were conducted in F344/N rats and B6C3F1 mice . The chemical was greater than 99% pure and was administered as a vapor by the inhalation route to mimic worker exposure; room air was used as the control exposure during these studies . Exposures were 6 hours per day (5 days per week), except in the single-exposure studies (4 hours) . Additional studies were performed to evaluate the potential for genetic damage in bacteria and in mammalian cells . In the single-exposure studies, the chemical was administered at exposure concentrations of 400-6,550 ppm in rats and 400-2,050 ppm in mice . In the 14-day studies, rats and mice were exposed at 400-6,400 ppm, and in the 13-week studies, rats and mice were exposed at 50-800 ppm . All rats in the single-exposure studies at 6,550 ppm died; compound-related deaths were not seen in other dosed groups . All mice at 2,050 ppm and 4/5 mice of each sex at 1,420 ppm died; compound-related mortality was not seen in other dosed groups . In the 14-day studies, all rats at 3,200 and 6,400 ppm and 2/5 female rats at 1,600 ppm died; all mice at 1,600, 3,200, and 6,400 and 1/5 male mice at 800 ppm died . Final mean body weights of surviving rats exposed at 800 or 1,600 ppm were 12%-33% lower than those of the controls; final mean body weights of surviving mice at 800 ppm were 10%-12% lower than those of the controls . Compound-related lesions included pulmonary hemorrhage and rhinitis in rats at 1,600 ppm and nephrosis in mice at 800 and 1,600 ppm . In the 13-week studies, no compound-related mortality was observed in rats; all mice exposed at 800 ppm died . No compound-related clinical signs were seen in rats or in surviving mice . The final mean body weight of rats exposed at 800 ppm was 23% lower than that of controls for males and 16% lower for females . Final body weights of surviving mice were unaffected by exposure . Inflammation of the nasal turbinates was seen in rats at 800 ppm but not at lower exposure concentrations . Renal tubular necrosis was seen in mice at 800 ppm but not at lowerconcentrations . Inflammation of the nasal turbinates was observed in female mice at 100, 200, 400, and 800 ppm and in male mice at 200, 400, and 800 ppm . The highest exposure concentration selected for the 2-year studies in rats was 400 ppm because of body weight effects and nasal lesions observed at 800 ppm . The highest concentration selected for the 2-year studies in mice was 100 ppm because the nasal lesions seen at 200 and 400 ppm were considered to be potentially life threatening . Two-Year Studies: The 2-year toxicology and carcinogenesis studies of 1,2-epoxybutane were conducted by exposing groups of 50 animals per species and sex to the chemical by inhalation, 6 hours per day 5 days per week . Rats were exposed at concentrations of 0, 200, or 400 ppm for 103 weeks and mice at 0, 50, or 100 ppm for 102 weeks . Body Weight and Survival in the Two-Year Studies: The survival of all groups of dosed rats was at least 50% until week 98, but final survival was reduced in the dosed groups (final survival-- male: control, 30/50; low dose, 18/50; high dose, 23/50; female: 32/50; 21/50; 22/50) . Mean body weights of control and exposed male rats were similar until week 86; thereafter, mean body weights of high dose male rats were 4%-8% lower than those of controls . Mean body weights of high dose female rats were 5%-10% lower than those of controls after week 22 . Survival in male mice was comparable among groups (final survival: 41/50; 45/50; 33/50) . Survival in female mice was greater than 50% in all groups at week 86 and then was reduced in high dose females toward the end of the stin all groups at week 86 and then was reduced in high dose females toward the end of the study (final survival: 29/50; 25/50; 9/50) . This decreased survival was associated with suppurative inflammation of the ovary and uterus . Klebsiella oxytoca was isolated from these ovarian/uterine lesions . Mean body weights of high dose male mice were 10&percnt;-14&percnt; lower than those of the controls after week 69; mean body weights of low dose male mice were 4&percnt;-8&percnt; lower than those of the controls after week 86 . Mean body weights of high dose female mice were 13&percnt;-23&percnt; lower than those of the controls after week 60, and mean body weights of low dose female mice were 12&percnt;-16&percnt; lower than those of the controls after week 73 . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Dosed rats had nonneoplastic lesions of the nasal cavity including inflammation, epithelial hyperplasia, squamous metaplasia, hyperostosis of the nasal turbinate bone, and atrophy of the olfactory epithelium . Seven papillary adenomas of the nasal cavity were seen in highdose male rats and two in high dose female rats . The historical incidences of nasal cavity adenomas in untreated male and untreated female F344/N rats are less than 0.1&percnt; . The incidences of alveolar/bronchiolar carcinomas (0/50; 1/50; 4/49) and adenomas or carcinomas (combined) (0/50; 2/50; 5/49) were increased in high dose male rats; no increased incidences of these tumors were observed in dosed female rats . Dosed mice had increased incidences of nonneoplastic lesions of the nasal cavity but no significant increase in the incidence of neoplastic lesions of the nasal cavity . The nonneoplastic lesions included suppurative inflammation (empyema), epithelial hyperplasia, erosion, regeneration, and squamous metaplasia in the nasal cavity; atrophy of the olfactory sensory epithelium; hyperplasia of the nasal gland (Bowman's glands); and inflammation and hyperplasia of the nasolacrimal duct . A single squamous cell papilloma was seen in the incisive duct of one high dose male mouse . Genetic Toxicology: 1,2-Epoxybutane was mutagenic in Salmonella typhimurium strains TA100 and TA1535 when tested with a preincubational protocol with or without rat liver S9, indicating that it is a direct-acting mutagen capable of inducing base-pair substitutions in prokaryotes; it did not cause gene reversion in strains TA1537 or TA98 . 1,2-Epoxybutane induced forward mutations at the TK locus of cultured mouse L5178Y lymphoma cells with and without metabolic activation . Both chromosomal aberrations andsister chromatid exchanges were induced in cultured Chinese hamster ovary cells after exposure to 1,2-epoxybutane in the presence and absence of metabolic activation . 1,2-Epoxybutane, when fed to male Drosophila, caused significant increases in the number of sex-linked recessive lethal mutations and reciprocal translocations in the germ cells . Data Audit: An audit of the experimental data was conducted for the 2-year studies of 1,2-epoxybutane . No data discrepancies were found that influenced the final interpretations . Conclusions: Under the conditions of these 2-year inhalation studies, there was clear evidence of carcinogenic activity of 1,2-epoxybutane for male F344/N rats, as shown by an increased incidence of papillary adenomas of the nasal cavity, alveolar/bronchiolar carcinomas, and alveolar/bronchiolar adenomas and carcinomas (combined) . There was equivocal evidence of carcinogenic activity for female F344/N rats, as shown by the presence of papillary adenomas of the nasal cavity . There was no evidence of carcinogenic activity for male or female B6C3F1 mice exposed at 50 or 100 ppm . 1,2-Epoxybutane exposure was associated with adenomatous hyperplasia and inflammatory lesions of the nasal cavity in rats and inflammatory lesions of the nasal cavity in mice . Synonyms: 1-butene oxide; 1,2-butene oxide; butylene oxide; 1,2-butylene oxide; ethyl ethylene oxide; ethyl oxirane Natl Toxicol Program Tech Rep Ser, 1988 May, 330, 1 - 166 NTP Toxicology and Carcinogenesis Studies of 4-Hexylresorcinol (CAS No . 136-77-6) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; 4-Hexylresorcinol, which is used as an anthelmintic and antiseptic, was nominated by the National Cancer Institute for study . Toxicology and carcinogenesis studies were conducted by administering 4-hexylresorcinol (greater than 99% pure) in corn oil by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 16 days, 13 weeks, or 2 years . Sixteen-Day and Thirteen-Week Studies: In the 16-day studies, groups of five rats and five mice of each sex were administered 0, 31.3, 62.5, 125, 250, or 500 mg/kg 4-hexylresorcinol . Survival was not affected . Decreased body weights were seen in male rats that received 250 or 500 mg/kg 4-hexylresorcinol . No other effects were observed . In the 13-week studies, groups of 10 rats and 10 mice of each sex were administered 0, 62.5, 125, 250, 500, or 1,000 mg/kg of the chemical, 5 days per week . All rats and male mice and 9/10 female mice that received 1,000 mg/kg died before the end of the studies . Final mean body weights of male rats that received 250 or 500 mg/kg were 22% or 38% lower than that of the vehicle controls; final mean body weights of female rats that received 250 or 500 mg/kg were 16% or 9% lower . No compound-related gross or microscopic pathologic effects were observed in rats . No body weight effects were observed for mice . Mild to moderate nephropathy was dose related in male and female mice . Based on these results, 2-year toxicology and carcinogenesis studies of 4-hexylresorcinol were conducted by administering 0, 62.5, or 125 mg/kg to groups of 50 F344/N rats and 50 B6C3F1 mice of each sex, 5 days per week . Body Weight and Survival in the Two-Year Studies: Mean body weights of high dose male rats were 7%-11% lower than those of the vehicle controls throughout the study . Mean body weights of low dose male and dosed female rats were similar to those of the vehicle controls . The body weights of dosed male and dosed female mice were comparable to those of vehicle controls except during the last 16 weeks of the studies, when body weights were 6%-16% lower in the dosed groups . No significant differences in survival were observed between any groups of rats or mice of either sex (male rats: vehicle control, 30/50; low dose, 29/50; high dose, 33/50; female rats: 28/50; 32/50; 30/50; male mice: 36/50; 26/50; 30/50; female mice: 35/50; 32/50; 35/50) . Nonneoplastic and Neoplastic Lesions in the Two-Year Studies: Two astrocytomas and an oligodendroglioma were observed in high dose male rats, a glioma was observed in one low dose male rat, and an oligodendroglioma was observed in one vehicle control male rat . These neoplasms were not considered to be related to 4-hexylresorcinol administration . Focal medullary hyperplasia of the adrenal gland was observed at increased incidences in dosed male mice (5/50; 16/50; 10/49) . Pheochromocytomas in male mice occurred with a marginal upward trend (1/50; 2/50; 5/49) . Historically, these neoplasms are observed in about 1% of corn oil vehicle control B6C3F1 male mice . The incidences of neoplasms of the harderian gland in male mice were slightly increased over those in the vehicle controls (adenomas or carcinomas, combined: 0/50; 4/50; 3/50) . Decreases were observed in the incidences of mononuclear cell leukemia in dosed male (12/49; 7/50; 1/50) and female (16/50; 3/50; 2/50) rats, hepatocellular adenomas or carcinomas (combined) in dosed male mice (21/50; 9/50; 9/50), and circulatory system tumors in male (10/50; 4/50; 2/50) and female (6/50; 2/49; 0/50) mice . These decreased incidences of tumors in rats and mice are considered to be possibly related to 4-hexylresorcinol administration . The incidences and severity of nephropathy (male: 39/50; 43/50; 47/50; female: 7/50; 40/49; 47/50) and incidences of osteosclerosis (male: 5/50; 5/50; 15/50; female: 21/50; 25/49; 40/50) were increased in both dosed male and female mice and are considered to be related to chemical exposure . Genetic Toxicology: 4-Hexylresorcinol was not mutagenic for Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 with or without S9 metabolic activation . 4-Hexylre, TA1535, or TA1537 with or without S9 metabolic activation . 4-Hexylresorcinol induced forward mutations at the TK locus in mouse L5178Y cells in the presence of S9; no response was observed in the absence of metabolic activation . In cytogenetic assays with cultured Chinese hamster ovary (CHO) cells, 4-hexylresorcinol caused an increase in the frequency of sister chromatid exchanges (SCEs) in the absence of metabolic activation; no induction of SCEs was observed in the presence of S9 . Chromosomal aberrations were not induced in CHO cells with or without metabolic activation . Data Audit: The data, documents, and pathology materials from the 2-year studies of 4-hexylresorcinol were audited at the NTP Archives . The audit findings show that the conduct of the studies is documented appropriately and support the data and results given in this Technical Report . Conclusions: Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenic activity of 4-hexylresorcinol for male or female F344/N rats given doses of 62.5 or 125 mg/kg . There was equivocal evidence of carcinogenic activity of 4-hexylresorcinol for male B6C3F1 mice, as shown by marginally increased incidences of pheochromocytomas (and hyperplasia) of the adrenal medulla and of harderian gland neoplasms . There was no evidence of carcinogenic activity for female B6C3F1 mice given doses of 62.5 or 125 mg/kg 4-hexylresorcinol . Decreased incidences of three tumors types were considered related to 4-hexylresorcinol administration: mononuclear cell leukemia in male and female rats, hepatocellular neoplasms in male mice, and circulatory system tumors in male and female mice . Synonyms: 4-hexyl-1,3-benzenediol; 4-hexyl-1,3-dihydroxybenzene Natl Toxicol Program Tech Rep Ser, 1988 Nov, 331, 1 - 182 NTP Toxicology and Carcinogenesis Studies of Malonaldehyde, Sodium Salt (3-Hydroxy-2-propenal, Sodium Salt) (CAS No . 24382-04-5) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; Malonaldehyde occurs as a natural metabolic byproduct of prostaglandin biosynthesis and as an end product of polyunsaturated lipid peroxidation . Toxicology and carcinogenesis studies of malonaldehyde were conducted by administering the chemical as malonaldehyde, sodium salt, a stabilized form of malonaldehyde, in distilled water by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 weeks, and two years . The study material was 63%-79% malonaldehyde, sodium salt, 22%-38% water, and 1% or less other impurities . The water content was taken into account when the dose mixtures were prepared . Fourteen-Day and Thirteen-Week Studies: In the 14-day studies, groups of five rats and five mice of each sex were dosed with 250, 500, 750, 1,000, or 1,500 mg/kg malonaldehyde, sodium salt . Controls were untreated . Rats and mice that received 1,500 mg/kg malonaldehyde, sodium salt, did not survive to the end of the 14-day studies . No compound-related gross lesions were seen in the dosed animals . In the 13-week studies, groups of 10 males and 10 females of each species were administered 0, 30, 60, 125, 250, or 500 mg/kg malonaldehyde, sodium salt . Nine of 10 male rats, 10/10 female rats, 3/10 male mice, and 1/10 female mice that received 500 mg/kg malonaldehyde, sodium salt, died before the end of the studies . Body weights were reduced by more than 15% in rats receiving 250 or 500 mg/kg and in mice receiving 500 mg/kg . Compound-related nonneoplastic lesions were present in the stomach, testis, and kidney of rats and in the pancreas, stomach, and testis of mice . Focal and multifocal erosive lesions were observed in the gastric mucosa of the glandular stomach in the 500 mg/kg groups of male and female rats . Dilatation of the gastric glands of the stomach mucosa occurred in the 500 mg/kg male mice . Lesions of the kidney included membranous glomerular nephropathy in the 250 and 500 mg/kg male rats and the 125, 250, and 500 mg/kg female rats and mineralization in the 250 and 500 mg/kg male rats and the 60, 125, 250, and 500 mg/kg female rats . Degeneration of the testicular germinal epithelium was observed in male rats and male mice receiving 250 and 500 mg/kg . Atrophy of the exocrine pancreas was seen in the 125, 250, and 500 mg/kg male and the 250 and 500 mg/kg female mice . Based on these results, 2-year studies of malonaldehyde, sodium salt, were conducted by exposing groups of 50F344/N rats of each sex at doses of 0, 50, or 100 mg/kg, administered 5 days per week for 103 weeks . Doses of 0, 60, or 120 mg/kg were administered in the same schedule to groups of 50 male and 50 female B6C3F1 mice . Body Weight and Survival in the Two-Year Studies: Final mean body weights at the end of the study were reduced by 26% and 36% for high dose male and female rats compared with those for the vehicle controls . The final mean body weight of high dose male mice was 92% that of the vehicle controls . The final mean body weights of low dose male mice, low dose rats, and all groups of female mice were comparable to those of the vehicle controls . The survival of high dose male and female rats was significantly lower than that of the vehicle controls, with survival declining rapidly after week 76 for high dose males and after week 59 for high dose females (survival-- male: vehicle control, 37/50; low dose, 33/50; high dose, 15/50; female: 37/50; 37/50; 14/50) . Survival of all groups of male mice was low (male: 24/50; 20/50; 14/50; female: 41/50; 38/50; 30/50) . Survival of the high dose groups of male mice was significantly lower than that of the vehicle controls; no other significant differences in survival were observed between any groups of mice . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: The incidences of a variety of nonneoplastic lesions were increased in dosed rats of each sex, primarily in the high dose male and female rat groups . These lesions were ulceration and inflammation of the glandular stomach; epithelial hyperplasia of the forestomach; inflammation of the cornea, retinal atrophy, and cataracts of the crysttion of the cornea, retinal atrophy, and cataracts of the crystalline lens; focal lipoid degeneration of the adrenal cortex; and diffuse pancreatic atrophy . Cytoplasmic vacuolization and cystic degeneration in the liver occurred at increased incidences in the high dose rat groups; in addition, the incidences of bile duct hyperplasia and bile duct fibrosis were increased in the high dose female and male rat groups, respectively . Bone marrow hematopoietic hyperplasia, hematopoiesis of the spleen, and ultimobranchial cysts of thyroid gland occurred with increased incidences in high dose female rats . The incidences of thyroid gland follicular cell adenomas or carcinomas (combined) were significantly increased in high dose male (vehicle control, 4/50; low dose, 8/49; high dose, 13/50) and female (2/50; 1/50; 7/50) rats . Follicular cell hyperplasia of the thyroid gland also occurred at an increased incidence in high dose female rats (10/50; 10/50;26/50) but not in male rats (9/50; 7/49; 7/50) . The incidence of pancreatic islet cell adenomas was increased in low dose male rats (0/49; 9/50; 1/49) . Adenomas and adenomas or carcinomas (combined) of the anterior pituitary gland occurred at significantly lower incidences in high dose rats than those in vehicle controls (combined incidence--male: 20/47; 14/49; 8/49; female: 18/49; 10/49; 2/48) . Nonneoplastic lesions that occurred at increased incidences in dosed mice included atrophy of the pancreatic acinus and dilatation of the uterus . Depigmentation of hair shafts and change of coat color from agouti to gray were observed in high dose mice . No compound-related neoplasms were observed in dosed mice . Genetic Toxicology: Malonaldehyde, sodium salt, was not mutagenic in the Salmonella typhimurium/microsome assay when tested at doses of up to 10,000 ug/plate in a preincubational protocol using the excision-repair deficient strains TA98, TA100, TA1535, and TA1537 with or without S9 metabolic activation . The chemical induced forward mutations in mouse L5178Y lymphoma cells in the absence of S9; it was not tested with S9 . Malonaldehyde, sodium salt was not mutagenic in the Drosophila melanogaster sex-linked recessive lethal mutagenicity test in which adult male flies were exposed either by feeding or by abdominal injection . In cytogenetic assays with cultured Chinese hamster ovary (CHO) cells, malonaldehyde, sodium salt, produced a dose-related increase in the frequency of sister-chromatid exchanges both in the presence and absence of rat liver S9; no increase in the number of chromosomal aberrations was observed in CHO cells in the absence or presence of S9 . Audit: The data, documents, and pathology materials from the 2-year studies of malonaldehyde, sodium salt, have been audited . The audit found no special circumstances or significant deficiencies in the conduct or documentation of the studies which needed to be taken into consideration for reporting purposes . Conclusions: Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenic activity for male and female F344/N rats administered malonaldehyde, sodium salt, as shown by the increased incidences of follicular cell adenomas or carcinomas (combined) of the thyroid gland . Pancreatic islet cell adenomas were also observed at an increased incidence in low dose male rats . There was no evidence of carcinogenic activity for B6C3F1 mice administered 60 or 120 mg/kg malonaldehyde, sodium salt, in distilled water by gavage 5 days per week for 2 years . Chemically related increased incidences of nonneoplastic lesions included ulcers and inflammation of the glandular stomach and epithelial hyperplasia of the forestomach; corneal inflammation, retinal atrophy, and cataracts of the crystalline lens; and cystic degeneration of the liver, bile duct fibrosis, and bile duct hyperplasia in rats . Most of these nonneoplastic lesions as well as the thyroid gland follicular cell neoplasms occurred primarily in the high dose rat groups, in which survival and final body weights were reduced in high dose male and female rats . Increased incidences of atrophy of the pancreatic acinus and pigmentation loss in hair shafts were seen in high dose mice . Synonyms: malonaldehyde, enol, sodium salt; propanedial, sodium; 3-hydroxy-2-propenal, sodium salt; sodium b-oxyacrolein Natl Toxicol Program Tech Rep Ser, 1988 May, 332, 1 - 172 NTP Toxicology and Carcinogenesis Studies of 2-Mercaptobenzothiazole (CAS No . 149-30-4) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; Toxicology and carcinogenesis studies of technical-grade 2-mercaptobenzothiazole (96%-97% pure), a rubber accelerant and preservative, were conducted by administering the chemical by gavage in a corn oil vehicle to groups of F344/N rats and B6C3F1 mice of each sex for 16 days, 13 weeks, or 2 years . 2-Mercaptobenzothiazole was nominated for study by the National Institute of Environmental Health Sciences and the National Institute for Occupational Safety and Health . Sixteen-Day and Thirteen-Week Studies: In 16-day studies, mean body weight gains of rats receiving 2,500 mg/kg were 6-7 g lower than those of vehicle controls; 4/5 male and 5/5 female mice dosed with 3,000 mg/kg and 4/5 female mice dosed with 1,500 mg/kg died; lethargy and prostration occurred in most of these animals after gavage . Based on these results, doses were selected for both species in the 13-week studies were 0, 94 (mice only), 188, 375, 750, and 1,500 mg/kg . In the 13-week studies, no chemical-related deaths occurred in rats, but body weight gains in males dosed with 1,500 mg/kg and in females dosed with 750 or 1,500 mg/kg were lower than those in the vehicle control groups . Hepatomegaly occurred at the two highest doses in males and at all doses in females; however, no microscopic pathologic changes were noted in any tissue . More than half the mice dosed with 1,500 mg/kg died, but no compound-related body weight changes occurred . Clinical signs in mice were dose related and included lethargy in animals dosed with 375 mg/kg and lacrimation, salivation, and clonic seizure in some dosed with 750 or 1,500 mg/kg . No association between these clinical signs of toxicity and gross or microscopic pathologic effects were observed . Doses selected for the 2-year studies were 0, 375, and 750 mg/kg for male rats and for mice of each sex and 0, 188, or 375 mg/kg for female rats . Body weight and Survival in the Two-Year Studies: Fifty animals of each species and sex were administered 2-mercaptobenzothiazole in corn oil by gavage 5 days per week for 103 weeks . Administration of 2-mercaptobenzothiazole resulted in decreased survival in dosed male rats (vehicle control, 42/50; low dose, 22/50; high dose, 20/50) and in the high dose group of female mice (37/50; 39/50; 22/50) but not in female rats (28/50; 31/50; 25/50) or in male mice (38/50; 33/50; 30/50) . No effect on body weight gain in dosed rats was observed; in dosed mice, minor reductions occurred between weeks 3 and 64, withrecovery thereafter . Postgavage lethargy and prostration occurred frequently in dosed rats and mice . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: The severity of nephropathy was increased in dosed male rats . Ulcers and inflammation of the forestomach were prevalent in dosed rats, as were increased incidences of epithelial hyperplasia and hyperkeratosis in male rats, but no neoplasms of the forestomach were observed . There were no increases of nonneoplastic lesions in mice which were considered to be compound related . The incidences of a variety of tumors were increased in rats dosed with 2-mercaptobenzothiazole; some of the increased incidences were not dose related . In low dose male rats, increased incidences (P<0.01) were observed for mononuclear cell leukemia (7/50; 16/50; 3/50) and pancreatic acinar cell adenomas (2/50; 13/50; 6/49) . Increased tumor incidences with dose-related trends (P<0.05) included pituitary gland adenomas in females (15/49; 24/50; 25/50), preputial gland adenomas or carcinomas (combined) in males (1/50; 6/50; 5/50), adrenal gland pheochromocytomas or malignant pheochromocytomas (combined) in males (18/50; 27/50; 24/49), and pheochromocytomas in females (1/50; 5/50; 6/50) . These tumors were observed at significantly greater incidences (P</=0.05) in the high dose groups than in the vehicle controls . An increased incidence (P=0.028) of hepatocellular adenomas or carcinomas (combined) was observed only in low dose female mice (4/50; 12/49; 4/50) . No significant increases in tumor incidences were seen in male mice . Genetic Toxicology: 2-Mercaptobenzothgy: 2-Mercaptobenzothiazole was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 with or without metabolic activation . In the presence of rat liver S9, 2-mercaptobenzothiazole increased the frequency of chromosomal aberrations and sister chromatid exchanges (SCEs) in Chinese hamster ovary (CHO) cells, as well as mutations at the TK locus of mouse L5178Y lymphoma cells . Audit: The data, documents, and pathology materials from the 2-year studies of 2-mercaptobenzothiazole were audited at the NTP Archives . The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report . Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity of 2-mercaptobenzothiazole for male F344/N rats, indicated by increased incidences of mononuclear cell leukemia, pancreatic acinar cell adenomas, adrenal gland pheochromocytomas, and preputial gland adenomas or carcinomas (combined) . There was some evidence of carcinogenic activity for female F344/N rats, indicated by increased incidences of adrenal gland pheochromocytomas and pituitary gland adenomas . There was no evidence of carcinogenic activity of 2-mercaptobenzothiazole for maleB6C3F1 mice dosed with 375 or 750 mg/kg . There was equivocal evidence of carcinogenic activity for female B6C3F1 mice, indicated by increased incidences of hepatocellular adenomas or carcinomas (combined) . Synonyms and Trade Names: Captax; Dermacid; Mertax; Thiotax; 2(3H)-benzothiazolethione; 2-benzothiazolyl mercaptan Natl Toxicol Program Tech Rep Ser, 1988 Feb, 334, 1 - 158 NTP Toxicology and Carcinogenesis Studies of 2-Amino-5-Nitrophenol (CAS No . 121-88-0) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; 2-Amino-5-nitrophenol is used as a colorant in semipermanent hair dyes and in the manufacture of C.I . Solvent Red 8, an azo dye for synthetic resins, lacquers, and wood stains . 2-Amino-5-nitrophenol was nominated for toxicology and carcinogenesis studies by the National Cancer Institute because of widespread human exposure associated with its use in hair dyes . Toxicology and carcinogenesis studies were conducted by administering 2-amino-5-nitrophenol (98% pure) by gavage in corn oil 5 days per week to groups of F344/N rats and B6C3F1 mice of each sex in 16-day, 13-week, and 2-year studies . In the 2-year studies, male and female rats were given doses of 0, 100, or 200 mg/kg and male and female mice were given doses of 0, 400, or 800 mg/kg . Sixteen-Day and Thirteen-Week Studies: During the 16-day studies, F344/N rats of each sex received 0, 156, 313, 625, 1,250, or 2,500 mg/kg 2-amino-5-nitrophenol by gavage in corn oil vehicle . One of the five males that received 2,500 mg/kg, 1/5 females that received 1,250 mg/kg, and 2/5 females that received 313 mg/kg died before the end of the studies . Final mean body weights of rats that received 1,250 or 2,500 mg/kg were 11% and 30% lower than that of vehicle controls for males and 9% and 13% lower for females . B6C3F1 mice of each sex received doses of 0, 313, 625, 1,250, 2,500, or 5,000 mg/kg 2-amino-5-nitrophenol . Two of five males and 5/5 females that received 5,000 mg/kg, 3/5 males and 3/5 females that received 2,500 mg/kg, 3/5 females that received 1,250 mg/kg, 1/5 females that received 625 mg/kg, and 2/5 male vehicle controls died before the end of the studies . Final mean body weights of chemically exposed mice were not different from those of the vehicle controls . Rats that received 625, 1,250, or 2,500 mg/kg and male mice that received 5,000 mg/kg had loose stools . In 13-week studies, F344/N rats and B6C3F1 mice of both sexes received 0, 100, 200, 400, 800, or 1,600 mg/kg 2-amino-5-nitrophenol by gavage in corn oil . Five of 10 male and 2/10 female rats that received 1,600 mg/kg, 1/10 male and 3/10 female rats that received 800 mg/kg, and 1/10 male rats that received 400 mg/kg died before the end of the studies . Final mean body weights of males that received 400, 800, or 1,600 mg/kg were 10%, 25%, and 43% lower than that of vehicle controls . The final mean body weight of females that received 1,600 mg/kg was 16% lower that of vehicle controls . Four of 10 male and 3/10 female mice that received 1,600 mg/kg died before the end of the 13-week studies . The final mean body weight of male mice that received 1,600 mg/kg was 11% lower than that of vehicle controls; male and female mice that received 1,600 mg/kg appeared lethargic . During the 13-week studies, acute/chronic perivasculitis of vessels of the cecum and colon was observed in rats that received 400, 800, or 1,600 mg/kg and in mice that received 1,600 mg/kg . Body Weight and Survival in the Two-Year Studies: Mean body weights of rats receiving 200 mg/kg were 5%-10% lower than those of vehicle controls after week 33 for males and 4%-5% lower than those of vehicle controls after week 93 for females . Survival of male rats was significantly lower than that of vehicle controls after week 99 for the 100 mg/kg dose group and after week 75 for the 200 mg/kg dose group (final survival: vehicle control, 33/50; 100 mg/kg group, 16/50; 200 mg/kg group, 4/50) . Survival of female rats was comparable to that of vehicle controls (30/50; 32/50; 29/50) . Loose or poorly formed stools were observed for male rats and occasionally for females that received 200 mg/kg . Mean body weights of mice that received 800 mg/kg were 8%-11% lower than those of vehicle controls between weeks 29 and 74 for males and 8%-13% lower than those of vehicle controls after week 69 for females; mean body weights of mice that received 400 mg/kg were greater than those of vehicle controls after week 69 for males and 5%-9% lower than those of vehicle controls after week 69 for females . Survival of mice that received 800 mg/kg was significantly reduced compared with that of ose of vehicle controls after week 69 for females . Survival of mice that received 800 mg/kg was significantly reduced compared with that of vehicle controls after week 20 for males and week 22 for females and was not considered adequate to evaluate a carcinogenic response (final survival--male: vehicle control, 31/50; 400 mg/kg group, 36/50; 800 mg/kg group, 12/50; female: 37/50; 36/50; 10/50) . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Pigmentation was present at increased incidences in all groups of chemically exposed animals and was characterized by varying amounts of an orange, granular pigment present in the fibrous connective tissue of the lamina propria, in the submucosa, and around vessels in the submucosa of the cecum and colon . Pigmentation of the rectum was observed at increased incidences in male rats that received 100 mg/kg, male and female rats that received 200 mg/kg, and both groups of chemically exposed mice . No pigmentation was found in the intestines of vehicle control rats or mice . Associated with pigmentation was an increased incidence of acute/chronic inflammation in the cecum and colon of all groups chemically exposed rats and mice; this inflammation was similar to that observed in the 13-week studies but was of greater severity . Acute/chronic inflammation was also present in the rectum of male rats that received 100 mg/kg, male and female rats that received 200 mg/kg, and male mice that received 800 mg/kg . The incidence of pancreatic acinar cell adenomas was significantly increased (P&le;0.002) in male rats that received 100 mg/kg 2-amino-5-nitrophenol (vehicle control, 1/50; 100 mg/kg, 10/50; 200 mg/kg, 3/49); the increase was considered to be associated with chemical exposure . The reduced survival of male rats that received 200 mg/kg markedly reduced the sensitivity of this group for detecting the presence of neoplasms . The incidences of adenomas or carcinomas (combined) of the preputial or clitoral glands were marginally increased in male or female rats that received 200 mg/kg 2-amino-5-nitrophenol (preputial gland: 3/50; 2/50; 5/50; clitoral gland: 3/50; 3/50; 7/50) . Neoplasms found in the intestinal tract of 3/50 male rats that received 100 mg/kg (one leiomyoma of the small intestine, one adenocarcinoma of the jejunum, one leiomyoma of the cecum), 2/50 male rats that received 200 mg/kg (one lipoma and one osteosarcoma of the cecum), and 1/50 female rats that received 200 mg/kg (one leiomyoma of the cecum) were not considered to be the result of chemical exposure . No compound-related neoplasms were found in mice exposed to 2-amino-5-nitrophenol in the 2-year studies . Genetic Toxicology: 2-Amino-5-nitrophenol was mutagenic in Salmonella typhimurium strains TA98, TA100, and TA1537 when tested in a preincubation protocol with and without exogenous metabolic activation, and it exhibited equivocal mutagenic activity in strain TA1535 in the presence of induced liver S9 . 2-Amino-5-nitrophenol induced forward mutations in mouse L5178Y lymphoma cells in the absence of metabolic activation; it was not tested with S9 . An increase in chromosomal aberrations and sister chromatid exchanges was observed in cultured Chinese hamster ovary (CHO) cells following incubation with 2-amino-5-nitrophenol both in the presence and absence of exogenous metabolic activation . Data Audit: The data, documents, and pathology materials from the 2-year studies of 2-amino-5-nitrophenol were audited at the NTP Archives . The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report . Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity for male F344/N rats that received 100 mg/kg 2-amino-5-nitrophenol, as shown by the increased incidence of acinar cell adenomas of the pancreas . Reduced survival of male F344/N rats that received 200 mg/kg decreased the sensitivity of this group for detecting a carcinogenic response . There was no evidence of carcinogenic activity for female rats that received 100 or 200 mg/kg per day . Marginally increased incidences of preputial or clitoral gland adenomas or carcinomas (combined) occurred in male and female F344/N rats administered 200 mg/kg 2-amino-5-nitrophenol . There was no evidence of carcinogenic activity for B6C3F1 mice that received 400 mg/kg 2-amino-5-nitrophenol; reduced survival of B6C3F1 mice that received 800 mg/kg caused this group to be considered inadequate for detecting a carcinogenic response. Natl Toxicol Program Tech Rep Ser, 1988 Jun, 336, 1 - 170 NTP Toxicology and Carcinogenesis Studies of Penicillin VK (CAS No . 132-98-9) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; Penicillin VK, a widely used antibiotic for treatment of gram-positive coccal infections, was nominated for study by the National Cancer Institute because rodent carcinogenicity studies for this drug had not been performed . The chemical (94% or 98% pure, USP grade) was administered orally (by gavage in corn oil) because oral administration is the primary route used to treat infections in humans . Fourteen-day, 13-week, and 2-year studies were conducted in F344/N rats and B6C3F1 mice . Additional studies were performed to evaluate the potential for genetic damage in bacteria and mammalian cells . Fourteen-Day and Thirteen-Week Studies: In the 14-day studies, penicillin VK was administered at doses of 150-2,400 mg/kg . No compound-related deaths or dose-related histopathologic lesions were seen in rats or mice . Final mean body weights of dosed male rats were 5%-17% lower than that of controls; weights of dosed and control female rats were comparable . Final mean body weights of dosed mice were 5%-9% lower than those of controls . Diarrhea was observed in all dosed groups of rats and mice . In the 13-week studies, male and female rats received doses of 180-3,000 mg/kg and male and female mice received doses of 250-3,000 mg/kg . No compound-related deaths were seen in rats or mice . Final mean body weights of rats that received 3,000 mg/kg were 11% lower than those of the vehicle controls for males and 6% lower for females . For mice, mean body weights were comparable . Diarrhea occurred in male rats at doses of 750 mg/kg and above and in female rats at doses of 1,500 and 3,000 mg/kg . Mucous cell metaplasia of the glandular stomach was observed in male and female rats receiving 1,500 and 3,000 mg/kg . Lesions of the glandular stomach (inflammation, mucous cell metaplasia, and eosinophilic cytoplasmic change) and the forestomach (papillary hyperplasia and hyperkeratosis) were seen in all groups of dosed mice . The severity of lesions at 1,000 mg/kg or below was considered minimal . Based on these results, doses selected for rats and mice in the 2-year studies were 0, 500, or 1,000 mg/kg . Body Weight and Survival in the Two-Year Studies: Mean body weights of dosed and vehicle control male and female rats and male mice were comparable . Mean body weights of dosed female mice were 4%-16% lower than those of the vehicle controls from week 28 to the end of the study . Diarrhea was observed for dosed male and female rats and for dosed male mice . Survival of low and high dose male rats and high dose female rats was reduced (male rats: vehicle control, 34/50; low dose, 19/50; high dose, 16/50;female rats: 29/50; 26/50; 16/50) . Survival of male and female mice was comparable to that of the vehicle controls (male mice: 24/50; 36/50; 26/50; female mice: 36/50; 32/50; 32/50) . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Nonneoplastic lesions occurred at low incidences in the nasal mucosa, lung, and forestomach of dosed male rats and in the nasal mucosa and lung of dosed female rats . Congestion and aspiration pneumonia occurring in dosed rats dying before week 104 was the principal cause of death in these animals . Nonneoplastic lesions of the gastric fundal gland (eosinophilic cytoplasmic change and dilatation) and glandular stomach (cyst, chronic focal inflammation, hyperplasia, fibrosis, and squamous metaplasia) were seen in dosed male and female mice, and lesions of the gallbladder (eosinophilic cytoplasmic change) were seen in male mice . Slight increases in the incidences of adenomas of the pituitary gland in high dose male rats and of fibroadenomas or adenomas (combined) of the mammary gland in low dose female rats were observed . These were not considered to be compound-related lesions . The incidence of hepatocellular adenomas was decreased in high dose male mice (14/50; 15/49; 4/49) . No compound-related neoplasms were seen in female mice . Genetic Toxicology: Penicillin VK was not mutagenic in Salmonella typhimurium strains TA98, TA100, TA1535, or TA1537 with or without exogenous metabolic activation . The chemical was mutagenic onl exogenous metabolic activation . The chemical was mutagenic only with activation in the mouse lymphoma L5178Y/TK&plusmn; forward mutation assay . Incubation of Chinese hamster ovary cells with penicillin VK resulted in increased frequencies of sister chromatid exchanges and chromosomal aberrations in the absence of metabolic activation under the conditions of delayed harvest to compensate for chemical-induced cell cycle delay, no effects from penicillin VK exposure were observed in these cells in the presence of S9 . Audit: The data, documents, and pathology materials from the 2-year studies of penicillin VK were audited . The audit findings show that the conduct of the studies is documented and support the data and results given in this Technical Report . Conclusions: Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenic activity of penicillin VK for F344/N rats or for B6C3F1 mice administered 500 or 1,000 mg/kg penicillin VK in corn oil gavage, 5 days per week for 2 years . Nonneoplastic lesions were seen in the glandular stomach of dosed mice . Decreased survival of low and high dose male rats and of high dose female rats reduced the sensitivity of the studies for determining the presence or absence of a carcinogenic response in this species . Synonyms: 4-thia-1-azabicyclo(3.2.0)heptane-2-carboxylic acid, 3,3-dimethyl-7-oxo-6-(2-phenoxy-acetamide)-, monopotassium salt; penicillin V potassium; penicillin V potassium salt; D-a-phenoxymethylpenicillinate K salt; phenoxymethylpenicillin potassium; PVK Trade Names: Antibiocin; Apsin VK; Aracil; Arcasin; Aspin VK; Beromycin; Beromycin 400; Betapen VK; Calciopen K; Cliacil; Compocillin VK; Distakaps V-K; Distaquaine V-K; Dowpen V-K; DQV-K; Fenoxypen; Icipen; Isocillin; Ispenoral; Ledercillin VK; Megacillin oral; Oracil-VK; Orapen; Ospeneff; Pedipen; Penagen; Pencompren; Pen-Vee K; Pen-V-K powder; Penvikal; Pfizerpen VK; Qidpen VK; Robicillin VK; Rocillin-VK; Roscopenin; SK-Penicillin VK; Stabilin VK Syrup 125; Stabilin VK Syrup 62.5; Sumapen VK; Suspen; Uticillin VK; V-Cil-K; V-Cillin K; Veetids; Vepen Natl Toxicol Program Tech Rep Ser, 1988 Jun, 337, 1 - 183 NTP Toxicology and Carcinogenesis Studies of Nitrofurazone (CAS No . 59-87-0) in F344/N Rats and B6C3F1 Mice (Feed Studies); National Toxicology Program ; Nitrofurazone is a synthetic furan derivative, active against a broad spectrum of bacteria, which has been widely used in veterinary and human medicine . Toxicology and carcinogenesis studies were conducted by feeding diets containing nitrofurazone (99% pure) to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 weeks, or 2 years . Fourteen-Day and Thirteen-Week Studies: Groups of five males and five females of each species were fed diets containing 0, 630, 1,250, 2,500, 5,000, or 10,000 ppm for 14 consecutive days . Early deaths occurred in all groups of rats receiving 5,000 or 10,000 ppm nitrofurazone . The surviving rats in the lower two dose groups gained weight, but weight gain was decreased as the dose of nitrofurazone was increased . Feed consumption by rats of each sex was decreased at all doses above 630 ppm . In all dosed groups, clinical signs of toxicity included rough hair coats and lethargy . At doses of 2,500 ppm and above, rats of each sex exhibited intermittent episodes of seizures and lethargy . All mice that received 2,500, 5,000, or 10,000 ppm nitrofurazone and 3/5 males that received 1,250 ppm died before the end of the 14-day studies; the surviving dosed mice (except females at 630 ppm) lost weight . A dose-related decrease in feed consumption was observed at all doses above 630 ppm . Clinical signs included rough hair coats and convulsive seizures . In the 13-week studies, groups of 10 rats of each sex were given diets containing 0, 150, 310, 620, 1,250, or 2,500 ppm nitrofurazone . No deaths were observed and all animals gained weight, but the magnitude of weight gain was dose dependent with decrements in final mean body weight for the highest dose group reaching 55% in males and 36% in females . Other evidence of chemically related toxicity included convulsive seizures, osteoporosis, degenerative arthropathy, and gonadal hypoplasia in both sexes at the two highest doses . Groups of 10 mice of each sex were given diets containing 0, 70, 150, 310, 620, or 1,250 ppm nitrofurazone for 13 weeks . Early deaths were observed in the two highest dose groups of each sex . The final mean body weights of male and female mice in the 1,250-ppm groups were about 20% lower than those of the controls; weight gains of the other dosed mice were comparable to those of the controls . Stimulus-induced convulsive seizures were observed for all mice in the two highest dose groups . Testicular hypoplasia was observed in the two highest dose groups of male mice . Body Weight and Survival in the Two-Year Studies: Dietary concentrations for the 2-year studies were 0, 310, or 620 ppm for rats and 0, 150, or 310 ppm for mice (50 animals per dose group) . Mean body weights of high dose male rats were lower than those of the controls after week 39; mean body weights of low dose male rats and of the controls were comparable throughout the study . Final mean body weights of low and high dose female rats were 9% and 21% lower than those of the controls . Dosed rats consumed less feed than did the controls . The average amount of nitrofurazone consumed per day was approximately 11-12 or 24-26 mg/kg by low or high dose male and female rats . The survival of the high dose group of male rats was lower than that of the controls after week 92 (final survival-- male: control, 33/50; low dose, 30/50; high dose, 20/50; female: 28/50; 37/50; 31/50) . Mean body weights of dosed mice were similar to or somewhat greater than those of controls throughout most of the studies . The average daily feed consumption by dosed mice was similar to that of controls . The average amount of nitrofurazone consumed per day was approximately 14-16 or 29-33 mg/kg for low or high dose male and female mice . The survival of the high dose group of male mice was lower than that of the controls after week 88 (final survival-- male: 39/50; 31/50; 27/50; female: 39/50; 40/50; 35/50) . In mice of each sex, nitrofurazone administration induced stimulus-sensitive convulsive seizures beginning at week 4 or 5 for high dose mice and week 24 for low dose female mice . These seizures were low dose female mice . These seizures were observed primarily in the first year of the study . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Degenerative changes involving the vertebral and femoro-tibial (knee) joints were observed at increased incidences in dosed rats . The degenerative changes primarily affected the articular cartilage and were similar to those seen in the 13-week studies . Degeneration of the sternal synchondroses was increased in high dose female rats . The osteoporosis seen in the 13-week studies was not observed in the 2-year studies . Testicular degeneration, characterized by atrophy of the germinal epithelium and aspermatogenesis, was observed at increased incidences in dosed male rats (control, 12/50; low dose, 49/50; high dose, 47/50) . Adenomas of the sebaceous glands and trichoepitheliomas or sebaceous adenomas (combined) of the skin were observed in high dose male rats (0/50; 0/50; 5/50) . Carcinomas of the preputial gland were increased in dosed male rats (1/50; 8/50; 5/50) . The incidences of preputial gland adenomas or carcinomas (combined) in dosed male rats were not statistically greater than that in the controls (9/50; 16/50; 7/50) . However, in the low dose group, the incidence is greater than the highest incidence observed in historical untreated control groups (9/50) . In addition, hyperplasia of the preputial gland was observed in six low dose male rats in which neither adenomas nor carcinomas occurred . The incidence of mesotheliomas of the tunica vaginalis in low dose male rats was greater than that in the controls (0/50; 7/50; 2/50) . Fibroadenomas of the mammary gland occurred at markedly increased incidences in dosed female rats (8/49; 36/50; 36/50) . Three adenocarcinomas were also observed (1/49; 0/50; 2/50) . Ovarian atrophy (7/47; 44/50; 38/50) and tubular cell hyperplasia of the ovary (1/47; 23/50; 21/50) were observed at markedly increased incidences in dosed female mice . The incidences of benign mixed tumors (0/47; 17/50; 20/50), granulosa cell tumors (1/47; 4/50; 9/50), and granulosa cell tumors or luteomas (combined) (3/47; 6/50; 9/50) of the ovary were increased in exposed female mice . Mononuclear cell leukemia in rats occurred with negative trends (male: 21/50; 23/50; 6/50; female: 15/49; 2/50; 2/50) . In female mice, the incidences of adenomas or carcinomas (combined) of the anterior pituitary gland occurred with a negative trend (10/50; 7/50; 2/49) . The incidences of testicular interstitial cell tumors were decreased in dosed male rats (45/50; 30/50; 28/50) . Genetic Toxicity: Nitrofurazone was mutagenic in Salmonella typhimurium strains TA98 and TA100 both with and without exogenous metabolic activation . The responses in strains TA1535 and TA1537 were more varied: nitrofurazone was mutagenic in strain TA1535 only in the presence of S9 and produced no consistent increase in gene reversions in strain TA1537 with or without S9 . In the absence of metabolic activation, nitrofurazone induced forward mutations at the TK+/- locus of mouse L5178Y lymphoma cells; the chemical was not tested with S9 . Treatment of cultured Chinese hamster ovary cells with nitrofurazone in the absence of S9 produced a dose-related increase in sister chromatid exchanges and chromosomal aberrations; with S9, sister chromatid exchanges were increased, but no induction of chromosomal aberrations was observed . Audit: The data, documents, and pathology materials from the 2-year studies of nitrofurazone were audited at the NTP Archives . The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report . Conclusions: Under the conditions of these 2-year feed studies, there was equivocal evidence of carcinogenic activity of nitrofurazone for male F344/N rats as shown by the occurrence of sebaceous gland adenomas and trichoepitheliomas of the skin, mesotheliomas of the tunica vaginalis, and preputial gland tumors . There was clear evidence of carcinogenic activity of nitrofurazone for female F344/N rats as shown by a markedly increased incidence of fibroadenomas of the mammary gland . There was no evidence of carcinogenic activity for male B6C3F1 mice fed diets containing nitrofurazone at concentrations of 150 or 310 ppm . There was clear evidence of carcinogenic activity of nitrofurazone for female B6C3F1 mice as shown by increased incidences of benign mixed tumors and granulosa cell tumors of the ovary . Administration of nitrofurazone was associated with decreased incidences of mononuclear cell leukemia in male and female rats, testicular interstitial cell tumors in male rats, and pituitary gland neoplasms in female mice . Convulsive seizures in mice of each sex, ovarian atrophy in female mice, testicular degeneration in rats, and degeneration of articular cartilage in rats were all associated with the administration of nitrofurazone . Synonyms: 5-nitro-2-furaldehyde semicarbazone; 2-{(5-nitro-2-furanyl)methylene}hydrazine carboximide Trade Names: Aldomycin; Amifur; Chemfuran; Coxistat; Furacin; Furacinetten; Furaplast; Furazol W; Furesol; Furracoccid; Mammex; Nefco; Nifuzon; Nitrofural; Vabrocid Natl Toxicol Program Tech Rep Ser, 1986 Dec, 327, 1 - 160 NTP Toxicology and Carcinogenesis Studies of Xylenes (Mixed) (60% m-Xylene, 14% p-Xylene, 9% o-Xylene, and 17% Ethylbenzene) (CAS No . 1330-20-7) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; The technical grade of xylenes (mixed) (hereafter termed xylenes) contains the three isomeric forms and ethylbenzene (percentage composition shown above) . The annual production for 1985 was approximately 7.4 x 108 gallons . Xylenes is used as a solvent and a cleaning agent and as a degreaser and is a constituent of aviation and automobile fuels . Xylenes is also used in the production of benzoic acid, phthalate anhydride, and isophthalic and terephthalic acids as well as their dimethyl esters . Toxicology and carcinogenesis studies of xylenes were conducted in laboratory animals because a large number of workers are exposed and because the long- term effects of exposure to xylenes were not known . Exposure for the present studies was by gavage in corn oil . In single-administration studies, groups of five F344/N rats and B6C3F1 mice of each sex received 500, 1,000, 2,000, 4,000, or 6,000 mg/kg . Administration of xylenes caused deaths at 6,000 mg/kg in rats and mice of each sex and at 4,000 mg/kg in male rats . In rats, clinical signs observed within 24 hours of dosing at 4,000 mg/kg included prostration, muscular incoordination, and loss of hind limb movement; these effects continued through the second week of observation . Tremors, prone position, and slowed breathing were recorded for mice on day 3, but all mice appeared normal by the end of the 2- week observation period . In 14- day studies, groups of five rats of each sex were administered 0, 125, 250, 500, 1,000, or 2,000 mg/kg, and groups of five mice of each sex received 0, 250, 500, 1,000, 2,000, or 4,000 mg/kg . Chemical- related mortality occurred only at 2,000 mg/kg in rats and at 4,000 mg/kg in mice . Rats and mice exhibited shallow breathing and prostration within 48 hours following dosing at 2,000 mg/kg . These signs persisted until day 12 for rats, but no clinical signs were noted during the second week for mice . In 13- week studies, groups of 10 rats of each sex received 0, 62.5, 125, 250, 500, or 1,000 mg/kg, and groups of 10 mice of each sex received 0, 125, 250, 500, 1,000, or 2,000 mg/kg . No deaths or clinical signs of toxicity were recorded in rats . However, high dose male rats gained 15% less weight and females 8% less weight than did the vehicle controls . Two female mice died at the 2,000 mg/kg dose . Lethargy, short and shallow breathing, unsteadiness, tremors, and paresis were observed for both sexes in the 2,000 mg/kg group within 5- 10 minutes after dosing and lasted for 15- 60 minutes . Two- year toxicology and carcinogenesis studies were conducted by administering 0, 250, or 500 mg/kg xylenes in corn oil by gavage to groups of 50 F344/N rats of each sex, 5 days per week for 103 weeks . Groups of 50 B6C3F1 mice of each sex were administered 0, 500, or 1,000 mg/kg xylenes on the same schedule . Although the mortality was dose related in male rats (final survival: vehicle control, 36/50; low dose, 26/50; high dose, 20/50), many of the early deaths in the dosed males were gavage related . Body weights of the high dose male rats were 5%- 8% lower than those of the vehicle controls after week 59 . The mean body weights of low dose and vehicle control male rats and those of dosed and vehicle control female rats were comparable . Survival rates of female rats and both sexes of dosed mice were not significantly different from those of the vehicle controls . The mean weights of dosed male and female mice were comparable to those of the vehicle controls . Hyperactivity lasting 5- 30 minutes was observed in high dose mice after dosing, beginning after week 4 and continuing through week 103 . At no site was the incidence of nonneoplastic or neoplastic lesions in dosed rats or mice of either sex considered to be related to the administration of xylenes . Neither xylenes nor any of its components (o- xylene, m-xylene, p- xylene, or ethylbenzene) were mutagenic when tested with or without metabolic activation in Salmonella typhimurium strains TA100, TA1535, TA97, or TA98 with the preincubation protocol . In addition, ethylbenzene was tested in cytogenetic assays using cultured Cetic assays using cultured Chinese hamster ovary cells both with and without metabolic activation; neither sister- chromatid exchanges nor chromosomal aberrations were induced by ethylbenzene . An audit of the experimental data was conducted for the 2-year studies of xylenes . No data discrepancies were found that influenced the final interpretations . Under the conditions of these 2-year gavage studies, there was no evidence of carcinogenicity of xylenes (mixed) for male or female F344/N rats given 250 or 500 mg/kg or for male or female B6C3F1 mice given 500 or 1,000 mg/kg. Phytomedicine, 2003 Mar, 10(2-3), 139 - 44 Evaluation of the mutagenic, antimutagenic and antiproliferative potential of Croton lechleri (Muell . Arg.) latex; Rossi D et al.; Sangre de Drago is a red viscous latex extracted from Croton lechleri (Euphorbiaceae) cortex, renowned in South American popular medicine for its wound-healing properties . The in vitro antiproliferative effects were determined on the human myelogenous leukemia K562 cells line (IC50 = 2.5 +/- 0.3 microg ml(-1)) . The mutagenic and antimutagenic activity of C . lechleri sap was examined by means of the Ames/Salmonella test . No mutagenic activity was found on the Salmonella typhimurium strains T98 and T100, either with or without S9 activation . On the other hand, the sap showed an inhibitory effect against the mutagenic activity of the indirectly acting mutagen 2-Aminoanthracene in presence of S9 and a moderate protective activity against directly acting mutagens Sodium Azide and 2-Nitrofluorene . Therefore we suggest that C . lechleri sap interacts with the enzymes of the S9 mix, thereby inhibiting the transformation of 2-Aminoantracene into its active forms. Biomed Sci Instrum, 2003, 39, 377 - 82 Enhanced heat-induced cellular leakage and death of Staphylococcus aureus and Salmonella typhimurium by 2,3 Butanedione; Farah IO; Influence of diacetyl on cellular leakage and/or death of Staphylococcus aureus (S . aureus; FRI-100) and Salmonella typhimurium (S . typhimurium) in the presence and absence of 30% sucrose and NZ-amine broth at 37, 45 and 55 degrees C was studied using Microbiological and Spectrophotmetric techniques . Diacetyl exists naturally in starter distillate and is usually added to enhance the flavor at the end of the fermentation process . Our objective was to examine its use before the onset of fermentation towards the safety of fermented products . Results showed significant difference (p < 0.05) between control and diacetyl treatments; average mean difference was > 5 log colony forming units per ml (CFU/ml) within 1 hour (h) . Interesting trends were also observed when differences with respect to absorbance ratios when data was normalized . Results also showed that diacetyl (0.1%) caused more cellular leakage and death of S . aureus at 45 degrees C as compared to 37 degrees C, and that cellular leakage per se was not directly related to death . Diacetyl, however, caused rapid death of S . aureus and S . typhimurium in the presence of 30% sucrose and NZ-amine broth at 55 degrees C; > 7 log CFU/ml death within 1 and 2 h respectively . We also conducted a study with commercial starter distillate (7%) and proved its ability to control both organisms under the same test conditions within 1 h at 55 degrees C . It is concluded that diacetyl is a potential candidate for the control of foodborne pathogens especially under low water activity conditions such as those encountered during meat fermentation. Natl Toxicol Program Tech Rep Ser, 1988 Jun, 339, 1 - 170 NTP Toxicology and Carcinogenesis Studies of 2-Amino-4-Nitrophenol (CAS No . 99-57-0) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; 2-Amino-4-nitrophenol is used to color semipermanent hair dyes and in the manufacture of mordant dyes for leather, nylon, silk, wool, and fur . 2-Amino-4-nitrophenol was nominated by the National Cancer Institute for toxicology and carcinogenesis studies because of widespread human exposure associated with its manufacture and use . Toxicology and carcinogenesis studies were conducted by administering 2-amino-4-nitrophenol (98% pure) in corn oil by gavage, 5 days per week, to groups of F344/N rats and B6C3F1 mice of each sex in 15-day, 13-week, and 2-year studies . Fifteen-Day and Thirteen-Week Studies: During the 15-day studies, rats and mice received doses of 0, 313, 625, 1,250, 2,500, or 5,000 mg/kg . All rats that received 2,500 or 5,000 mg/kg and all female rats that received 1,250 mg/kg died before the end of the studies . Final mean body weights of chemically exposed rats surviving to the end of the studies were comparable to those of vehicle controls . Diarrhea was observed in all groups of exposed rats except those receiving 313 mg/kg . All mice that received 2,500 or 5,000 mg/kg, 2/5 males and all females that received 1,250 mg/kg, and 1/5 females that received 313 mg/kg died before the end of the studies . Final mean body weights of exposed mice surviving until the end of the studies were comparable to those of vehicle controls . In 13-week studies, F344/N rats and B6C3F1 mice of each sex received 2-amino-4-nitrophenol at doses of 0, 62.5, 125, 250, 500, or 1,000 mg/kg . All rats that received 1,000 mg/kg and 2/10 males and 2/10 females that received 500 mg/kg died before the end of the studies . The final mean body weight of male rats that received 500 mg/kg was reduced 10% compared with that of vehicle controls; final mean body weights of all other surviving exposed rat groups were comparable to those of vehicle controls . Diarrhea and lethargy were observed for rats that received 500 or 1,000 mg/kg . All male mice and most females that received 1,000 mg/kg and 4/10 females that received 500 mg/kg died before the end of the studies . Final mean body weights of chemically exposed mice were comparable to those of vehicle controls . No compound-related clinical signs were observed in mice during the studies . Mineralization of the renal cortex and degeneration of the renal tubular epithelium were observed in male and female rats that received 1,000 mg/kg and in males that received 500 mg/kg . Degeneration and necrosis of the renal tubular epithelium was observed in 5/10 male and 3/10 female mice that received 1,000 mg/kg . Body Weight and Survival in the Two-Year Studies: In the 2-year studies, rats and mice received 2-amino- 4- nitrophenol at doses of 0, 125, or 250 mg/kg . Mean body weights of male rats that received 250 mg/kg were 8%-10% lower than those of vehicle controls throughout most of the 2-year study . Mean body weights of female rats were comparable to those of vehicle controls . Soft stools and occasional diarrhea were observed in chemically exposed rats starting 6 months after the beginning of the studies . Survival of male rats that received 250 mg/kg was markedly lower than that of vehicle controls after week 89 (final survival: vehicle control, 32/50; 125 mg/kg group, 24/50; 250 mg/kg group, 10/50) . Survival of female rats was comparable among all groups (final survival: 25/50; 27/50; 31/50) . Mean body weights of male and female mice that received 250 mg/kg were comparable to those of vehicle controls; the mean body weights of female mice that received 125 mg/kg were as much as 17% greater than that of vehicle controls . Survival of all mouse groups was comparable during the 2-year studies (final survival: male-- 28/50; 29/50; 23/50; female--28/50; 31/50; 30/50) . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Pigmentation of the small and large intestines was present in exposed rats but not in vehicle controls . Ulcers and erosive lesions of the digestive tract were observed in male rats that received 250 mg/kg and to a lesser extent in male rats that received 125 mg/kg . A carcinoma of the colon occurrkg . A carcinoma of the colon occurred in one male rat that received 250 mg/kg; no other neoplasms were observed in the gastrointestinal tract of rats . No pigmentation, ulcers, or erosive lesions were found in the digestive tract of mice . The severity of nephropathy was markedly greater in exposed male rats than in vehicle controls . Associated with the nephropathy were nonneoplastic lesions indicative of reduced renal function and secondary hyperparathyroidism, including parathyroid hyperplasia, mineralization of various organs, and fibrous osteodystrophy . Renal tubular cell hyperplasia (1/50; 4/48; 5/50) and renal cortical (tubular cell) adenomas (0/50; 1/48; 3/50) occurred in male rats . Renal cortical adenomas are infrequently observed in male F344/N rats (historical incidence, 0.5&percnt;) . More preputial gland adenomas or carcinomas (combined) were observed in low dose male rats than in vehicle controls (3/50; 10/48; 3/50), whereas the incidences of clitoral gland neoplasms were decreased in dosed female rats (9/50; 6/50; 1/49) . Hemangiomas or hemangiosarcomas (combined) occurred in male mice that received 2-amino-4-nitrophenol (0/50; 1/50; 5/50); each tumor was present at a different site . The historical control incidence is 11&percnt; at the study laboratory and 6&percnt; in 2-year NTP studies . Genetic Toxicology: 2-Amino-4-nitrophenol was mutagenic in Salmonella typhimurium strains TA98 and TA100 with metabolic activation . 2-Amino-4-nitrophenol was not mutagenic in strains TA1535 or TA1537 . 2-Amino-4-nitrophenol was mutagenic in the mouse lymphoma L5178Y/TK&plusmn; assay without metabolic activation . It was not tested with activation . 2-Amino-4-nitrophenol induced sister chromatid exchanges (SCEs) and chromosomal aberrations in Chinese hamster ovary cells in the presence and absence of metabolic activation . Audit: The data, documents, and pathology materials from the 2-year studies of 2-amino-4-nitrophenol were audited at the NTP Archives . The audit findings show that the conduct of the studies is documented adequately and support the data and results given in this Technical Report . Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity of 2-amino-4-nitrophenol for male F344/N rats, as shown by increased incidences of renal cortical (tubular cell) adenomas . The incidences of renal tubular cell hyperplasia were also increased in male rats exposed to 2-amino-4-nitrophenol . The survival of male rats that received 2-amino-4-nitrophenol was reduced compared with survival of vehicle control male rats . There was no evidence of carcinogenic activity of 2-amino-4-nitrophenol for female F344/N rats or for male or female B6C3F1 mice that received 125 or 250 mg/kg per day. Natl Toxicol Program Tech Rep Ser, 1990 Mar, 340, 1 - 171 NTP Toxicology and Carcinogenesis Studies of Iodinated Glycerol (Organidin(R).) (CAS No . 5634-39-9) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; Toxicology and carcinogenesis studies of iodinated glycerol (Organidin(R)., a complex mixture prepared by the reaction of iodine with glycerol and found to contain 33% 3-iodo-1,2-propanediol as the major component) were conducted because of human exposure to iodinated glycerol as an expectorant and its possible relationship to the formation of alkyl iodides, e.g., methyl iodide, a suspected animal carcinogen . These studies were conducted by giving iodinated glycerol in water by gavage (5 days per week) to groups of F344/N rats and B6C3F1 mice for 16 days, 13 weeks, or 2 years . Genetic toxicology studies were conducted with iodinated glycerol in Salmonella typhimurium, mouse L5178Y lymphoma cells, Chinese hamster ovary (CHO) cells, and B6C3F1 mice (in vivo bone marrow micronucleus test) . Also, 3-iodo-1,2-propanediol was tested in S . typhimurium and B6C3F1 mice (in vivo micronucleus assay) . Sixteen-Day and Thirteen-Week Studies: Sixteen-day studies were conducted by giving iodinated glycerol at doses up to 1,000 mg/kg to rats and up to 500 mg/kg to mice . All female rats and 4/5 male mice in the highest dose group died before the end of the studies; there were no dose-related effects on body weights of male or female rats or male mice at the end of the studies . The forestomach of 2/5 female mice that received 500 mg/kg was thickened and granular . Thirteen-week studies were conducted by administering iodinated glycerol at doses up to 500 mg/kg to rats and mice . During these studies, 3/10 female rats and 1/10 female mice that received 500 mg/kg died . Final mean body weights of rats and mice that received 500 mg/kg were 4% lower than those of vehicle controls for males and 6%-7% lower for females . Kidney tubular cell lesions, including cortical necrosis, regeneration, and calcification, were observed at increased incidences in the highest dose group of female rats . Lymphoid hyperplasia of the stomach was observed in dosed male and female rats . Kidney tubular cell regeneration was also observed in dosed female mice . Inflammation or abscesses of mild-to-moderate severity and hyperplasia, acanthosis, and/or hyperkeratosis of mild-to-moderate severity were observed in the forestomach of the highest dosed group of female mice . Body Weight and Survival in the Two-Year Studies: Two-year studies were conducted by administering 0, 125, or 250 mg/kg iodinated glycerol in deionized water by gavage, 5 days per week for 103 weeks, to groups of 50 male F344/N rats and 50 male B6C3F1 mice . Groups of 50 female F344/N rats and 50 female B6C3F1 mice were administered iodinated glycerol on the same schedule at lower doses of 0, 62, or 125 mg/kg because of the increased severity of kidney and stomach lesions in the 13-week studies . Mean body weights of high dose male rats were 5%-10% lower than those of vehicle controls from week 43 to week 68 and 10%-13% lower from week 72 to the end of the studies . Mean body weights of low dose male rats and high dose female rats were 4%-9% lower than those of vehicle controls from week 88 to the end of the studies . The survival of the high dose group of male rats was considerably lower than that of the vehicle controls after week 86 . No other significant differences in survival were observed between any groups of rats of either sex (male: vehicle control, 28/50; low dose, 20/50, high dose, 2/50; female: 31/50; 30/50; 27/50) . Mean body weights of dosed and vehicle control male mice were similar . Mean body weights of high dose female mice were 6%-8% lower than those of vehicle controls from week 40 to week 64 and were 9%-13% lower thereafter . No significant differences in survival were observed between any groups of mice of either sex (male: 36/50; 40/50; 32/50; female: 40/50; 33/50; 38/50) . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: The incidence of mononuclear cell leukemia were increased in dosed male rats (vehicle control, 14/50; low dose, 29/50; high dose, 24/50) . Follicular cell carcinomas of the thyroid gland in male rats occurred at an increased incidence in low dose male rats (0/49; s of the thyroid gland in male rats occurred at an increased incidence in low dose male rats (0/49; 5/49; 1/49) . Reduced survival of high dose male rats may have been responsible for the decreased tumor incidence in this group relative to that in the low dose group . Follicular cell carcinomas were observed in one low dose and one high dose female rat . Follicular cell carcinomas of the thyroid gland have been observed in 3/293 water gavage vehicle control male F344/N rats and in 10/1,904 untreated control male F344/N rats . Adenomas of the nasal cavity were observed in two high dose male rats . Adenomas of the nasal cavity have not been observed in 300 water gavage vehicle control male F344/N rats or in 1,936 untreated control male F344/N rats . Squamous metaplasia and focal atrophy of the salivary glands were observed at increased incidences in dosed rats (squamous metaplasia--male: 0/48; 47/50; 48/49; female:1/49; 48/50; 49/50; focal atrophy--male: 1/48; 10/50; 30/49; female: 0/49; 4/50; 11/50) . In dosed female mice, adenomas of the anterior pituitary gland were increased (10/47; 15/45; 24/46) . The incidences of adenomas of the harderian gland in dosed female mice were increased (6/50; 8/40; 13/50) . A carcinoma of the harderian gland was observed in another high dose female mouse . Dilatation of the thyroid gland follicle and follicular cell hyperplasia were observed at increased incidences in dosed mice (dilatation--male: 0/48; 28/50; 32/50; female: 4/48; 11/48; 10/48; hyperplasia--male: 3/48; 46/50; 34/50; female: 2/48; 25/48; 35/48) . The incidences of follicular cell adenomas were 3/48, 6/50, and 0/50 for males and 2/48, 3/48, and 4/48 for females . Hyperkeratosis and acanthosis of the forestomach were observed at increased incidences in high dose male mice (hyperkeratosis: 0/49; 0/49; 5/50; acanthosis: 0/49; 1/49; 5/50) . Squamous cell papillomas were observed in female mice (1/49; 2/50; 5/49) . The historical incidence of forestomach squamous cell neoplasms is 4/339 (1.2&percnt;) in water gavage vehicle control female B6C3F1 mice and is 18/1,994 (0.9&percnt;) in untreated control female B6C3F1 mice . Squamous cell neoplasms were not observed in male mice . Genetic Toxicology: Treatment of the base-substitution mutant S . typhimurium strains TA100 and TA1535 with iodinated glycerol in a preincubational protocol with and without S9 resulted in a dose-related increase in the number of revertant colonies; no increase in revertants was observed with the frame-shift mutant strains TA98 or TA1537 . 3-Iodo-1,2-propanediol was also mutagenic in TA100 with or without S9; it was not mutagenic in TA98 . Iodinated glycerol increased the number of trifluorothymidine-resistant cells in mouse lymphoma L5178Y/TK&plusmn; assay in the absence of exogenous metabolic activation; it was not tested with activation . Iodinated glycerol induced sister chromatid exchanges (SCEs) and chromosomal aberrations in CHO cells without S9; with S9, the frequency of SCEs was increased more than without S9 but no chromosomal aberrations were induced . No increase in micronucleated polychromatic erythrocytes was observed in the bone marrow of B6C3F1 mice after injection with either iodinated glycerol or 3-iodo-1,2-propanediol . Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity for male F344/N rats administered iodinated glycerol, as indicated by increased incidences of mononuclear cell leukemia and follicular cell carcinomas of the thyroid gland . Adenomas of the nasal cavity in two high dose male rats may have been related to the administration of iodinated glycerol . There was no evidence of carcinogenic activity for female F344/N rats administered 62 or 125 mg/kg iodinated glycerol by gavage for 103 weeks . There was no evidence of carcinogenic activity for male B6C3F1 mice administered 125 or 250 mg/kg iodinated glycerol by gavage for 103 weeks . There was some evidence of carcinogenic activity for female B6C3F1 mice administered iodinated glycerol, as indicated by increased incidences of adenomas of the anterior pituitary gland and neoplasms of the harderian gland . Squamous cell papillomas of the forestomach may have been related to the administration of iodinated glycerol . Significant nonneoplastic lesions considered related to exposure of iodinated glycerol were squamous metaplasia and focal atrophy of the salivary gland in male and female rats . Dilatation of the thyroid gland follicle and follicular cell hyperplasia were observed in male and female mice . Synonyms or Trade Names: Organidin&reg;.; iodopropylidene glycerol Natl Toxicol Program Tech Rep Ser, 1989 Sep, 342, 1 - 208 NTP Toxicology and Carcinogenesis Studies of Dichlorvos (CAS No . 62-73-7) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; Toxicology and carcinogenesis studies of dichlorvos (99% pure), a contact and stomach poison for control of insects and parasites, were conducted by administering dichlorvos in corn oil by gavage to groups of F344/N rats and B6C3F1 mice of each sex for 13 weeks or 2 years . Previous feed studies were done by the National Cancer Institute using Osborne-Mendel rats and B6C3F1 mice . Thirteen-Week Studies: Thirteen-week studies with groups of 10 rats of each sex were conducted at doses of 0, 2, 4, 8, 16, 32, or 64 mg/kg dichlorvos in corn oil . All rats that received 32 or 64 mg/kg dichlorvos and 4/10 females that received 16 mg/kg died before the end of the studies . Final mean body weights of dosed and vehicle control rats were similar . Thirteen-week studies with groups of 10 mice of each sex were conducted at doses of 0, 5, 10, 20, 40, 80, or 160 mg/kg . All 10 male mice and 9/10 female mice that received 160 mg/kg and 5/10 male mice that received 80 mg/kg dichlorvos died before the end of the studies . Final mean body weights of dosed and vehicle control mice were similar . No compound-related gross or microscopic pathologic effects were observed in rats or mice . Two-year studies of dichlorvos were conducted by administering 0, 4, or 8 mg/kg dichlorvos, 5 days per week for 103 weeks, to groups of 50 F344/N rats of each sex . Groups of 50 male B6C3F1 mice were administered 0, 10, or 20 mg/kg dichlorvos on the same schedule, and groups of 50 B6C3F1 female mice were administered 0, 20, or 40 mg/kg dichlorvos . Body Weight and Survival in the Two-Year Studies: Mean body weights of dosed and vehicle control rats and mice were similar . No significant differences in survival were observed between any groups of rats or mice of either sex (rats--male: vehicle control, 31/50; low dose, 25/50; high dose, 24/50; female: 31/50; 26/50; 26/50; mice-- male: 35/50; 27/50; 29/50; female: 26/50; 29/50; 34/50) . Neoplastic Effects in the Two-Year Studies: Adenomas of the exocrine pancreas occurred at greater incidences in dosed rats than in vehicle controls (male: vehicle control, 25/50; low dose, 30/49; high dose, 33/50; female: 2/50; 3/47; 6/50) . Mononuclear cell leukemia in both dosed groups of male rats occurred more frequently than in vehicle controls (11/50; 20/50; 21/50) . Mammary gland fibroadenomas and fibroadenomas or adenomas (combined) in dosed female rats occurred at increased incidences relative to the vehicle controls (9/50; 19/50; 17/50) . Multiple fibroadenomas occurred in dosed female rats but not in vehicle controls (0/50; 6/50; 3/50); carcinomas occurred in two vehicle control and two low dose female rats . In mice, incidences of squamous cell papillomas of the forestomach were increased in the high dose groups compared with those in the vehicle controls (male: 1/50; 1/50; 5/50; female: 5/49; 6/49; 18/50) . Two high dose female mice developed forestomach squamous cell carcinomas . Genetic Toxicology: Dichlorvos was mutagenic in Salmonella typhimurium strain TA100 with and without metabolic activation but was not mutagenic in strain TA98 . Dichlorvos was mutagenic in the mouse lymphoma L5178Y/TK+/- assay without metabolic activation . Dichlorvos induced sister chromatid exchanges and chromosomal aberrations in Chinese hamster ovary cells in the absence and presence of metabolic activation . Conclusions: Under the conditions of these 2-year gavage studies, there was some evidence of carcinogenic activity of dichlorvos for male F344/N rats, as shown by increased incidences of adenomas of the exocrine pancreas and mononuclear cell leukemia . There was equivocal evidence of carcinogenic activity of dichlorvos for female F344/N rats, as shown by increased incidences of adenomas of the exocrine pancreas and mammary gland fibroadenomas . There was some evidence of carcinogenic activity of dichlorvos for male B6C3F1 mice, as shown by increased incidences of forestomach squamous cell papillomas . There was clear evidence of carcinogenic activity of dichlorvos for female B6C3F1 mice, as shown by increased incidences of forestomach squamous cell papils cell papillomas . Synonyms: 2,2-dichloroethenyl dimethyl phosphate; 2,2-dichlorovinyl dimethyl phosphate; O,O-dimethyl-O-(2,2-dichlorovinyl)phosphate; DDVP Trade Names: BAY-19149; DDVF; ENT-20738; OMS-14; SD 1750; Canogard&reg;.; Crossman's Fly-Cake&reg;.; Dedevap&reg;.; De-Pester Insect Strip&reg;.; Estrosol&reg;.; Herkol&reg;.; Kill-fly Resin Strip&reg;.; Lethalaire&reg;.; Mafu&reg;.; Misect&reg;.; Nogos&reg;.; Nuvan&reg;.; No-Pest Strip&reg;.; Oko&reg;.; Phoracide&reg;.; Phosvit&reg;.; Vapona&reg;.; Vaponicide&reg;.; Vaporette Bar&reg; . Anthelmintics: Atgard&reg;.; Dichlorman&reg;.; Equigard&reg;.; Task&reg;. Natl Toxicol Program Tech Rep Ser, 1989 Aug, 344, 1 - 172 NTP Toxicology and Carcinogenesis Studies of Tetracycline Hydrochloride (CAS No . 64-75-5) in F344/N Rats and B6C3F1 Mice (Feed Studies); National Toxicology Program ; Tetracycline hydrochloride is a broad-spectrum antibiotic used for its bactericidal action in human and veterinary medicine . Toxicology and carcinogenesis studies of tetracycline hydrochloride (USP grade, 91% pure) were conducted by feeding diets containing tetracycline hydrochloride to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 weeks, or 2 years . Fourteen-Day and Thirteen-Week Studies: The same dietary concentrations were used for the 14-day and 13-week studies (0, 3,125, 6,250, 12,500, 25,000 and 50,000 ppm tetracycline hydrochloride) . In the 14-day studies, none of the rats or mice died . The final mean body weight of male rats that received 50,000 ppm was 24% lower than that of the controls . The final mean body weight of mice that received 50,000 ppm in the diet was 18% lower than that of the controls for males and 15% lower for females . No compound-related effects were observed in rats or mice at necropsy . During the 13-week studies, none of the rats or mice died . The final mean body weight of male rats that received 50,000 ppm was 18% lower than that of the controls . Compound-related effects included cytoplasmic vacuolization in the liver of male rats at 25,000 and 50,000 ppm . Bone tetracycline concentrations in rats and mice increased with increasing dose of tetracycline hydrochloride . The final mean body weight of mice that received 50,000 ppm was 16% lower than that of the controls for males and 6% lower for females . Estimated feed consumption by dosed rat and mouse groups was similar to that of the controls . No compound-related gross or microscopic pathologic effects were observed in mice . Based on these results, 2-year studies of tetracycline hydrochloride were conducted by feeding diets containing 0, 12,500, or 25,000 ppm tetracycline hydrochloride to groups of 50 rats and 50 mice of each sex for 103 weeks . Body Weight, Survival, and Feed Consumption in the Two-Year Studies: Mean body weights of dosed and control male and female rats were similar throughout most of the studies . The survival of both the low and high dose female groups was greater than that of the controls . No significant differences in survival were observed between any groups of male rats (male: control, 27/50; low dose, 24/50; high dose, 31/50; female: 27/50; 39/50; 38/50) . Mean body weights of dosed mice were markedly (more than 10%) lower than those of the controls throughout most of the studies . The survival rates of the dosed groups of male mice were greater than that of the control group . No significant differences in survival were observed between any groups of female mice (male: 31/50; 43/50; 43/50; female: 37/50; 35/50; 38/50) . Feed consumption was similar by dosed and control rats and mice of either sex throughout the studies . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: Basophilic cytoplasmic change and clear cell change were positively correlated with tetracycline hydrochloride administration in male rats . Otherwise, no significant increases in neoplastic or nonneoplastic lesions in rats or mice of either sex were considered related to tetracycline hydrochloride administration . The incidence of adenomas or carcinomas (combined) of the pancreatic islets in low dose male rats was greater than that in the controls (control, 0/49; low dose, 5/49; high dose, 0/49) . This marginal effect in the low dose group was not considered to be chemically related . The historical control rate of pancreatic islet cell neoplasms from previous studies at this laboratory is 6% (9/148) . Decreased incidences and severity of chronic nephropathy in male rats were associated with tetracycline hydrochloride administration (48/50; 35/50; 36/50) . Female mice administered tetracycline hydrochloride in feed did not develop hepatocellular adenomas or carcinomas (combined incidence: 10/49; 0/48; 0/50) . The historical control rate for hepatocellular adenomas or carcinomas (combined) from previous studies at this laboratory is 18/149 (12%) . Other decreases in tumor incidence involving several tissues were considered to be of ma tumor incidence involving several tissues were considered to be of marginal biologic significance . Genetic Toxicology: Tetracycline hydrochloride was not mutagenic in four strains of Salmonella typhimurium (TA98, TA100, TA1535, or TA1537) when tested in a preincubation protocol in the presence or absence of exogenous metabolic activation . Tetracycline hydrochloride was negative in the mouse lymphoma L5178Y/TK&plusmn; assay with or without induced rat liver S9 but gave a marginally positive response when tested in the presence of noninduced S9 . In cytogenetic assays with Chinese hamster ovary (CHO) cells, treatment with tetracycline hydrochloride, both with and without S9, did not induce chromosomal aberrations or sister chromatid exchanges (SCEs) . Tetracycline hydrochloride did not induce sex-linked recessive lethal mutations when administered by feeding or injection to adult male Drosophila . Conclusions: Under the conditions of these 2-year feed studies, there was no evidence of carcinogenic activity of tetracycline hydrochloride for male or female F344/N rats and B6C3F1 mice fed diets containing 12,500 or 25,000 ppm . Tetracycline hydrochloride-dosed female rats and male mice had greater survival rates than the respective controls during these studies . Dosed mice had lower body weight than controls, and dosed female mice had no hepatocellular adenomas or carcinomas . Trade Names for Tetracycline or Tetracycline hydrochloride: Achromycin; Amycin; Bristacycline; Cyclopar; Dumocyclin; Neocyclin B; Panmycin; Polycycline; Robitet; Ro-cycline; Steclin; Sumycin; Topicycline; Unimycin Unfallchirurg, 2003 Apr, 106(4), 334 - 8 {Spondylitis due to Salmonella typhimurium}; Mahlfeld K et al.; Very little is known about Salmonella typhimurium as an agent of spondylitis . Only single cases have been described in the international literature over the last years . We report on three patients suffering from spondylitis with Salmonella typhimurium being isolated as the triggering agent and point out the subtly differentiated diagnostic and therapeutic procedures, especially the possible complications of a Salmonella spondylitis . For one of the patients, we diagnosed a concomitant abdominal aortic aneurysm . Another patient sustained an infection of a known aortic aneurysm, which had been operated on 3 years ago . The source of the infection could be either the aneurysm or the spine, with the other structure being infected subsequently . We also discuss possible pathogenesis. Int J Infect Dis, 2003 Mar, 7(1), 53 - 60 Treatment of Salmonella meningitis: two case reports and a review of the literature; Owusu-Ofori A et al.; BACKGROUND: Salmonella species now represent a leading cause of Gram-negative bacterial meningitis in the developing world . Various drugs have been used for the treatment of Salmonella meningitis over the past decades, but mortality, neurologic sequelae and relapse rates remain high . In this report we describe two children aged 8 and 9 months who presented within a week to our hospital with Salmonella meningitis . They were treated with penicillin and chloramphenicol but progressed rapidly to death within 48 h . Aim: The aim of this article is to review all published English literature on the treatment of Salmonella meningitis and identify the best drug option for its treatment . This was done by comparing the outcomes such as cure, failure, relapse, and death rates . METHOD: A Medline electronic search was carried out to find and retrieve articles that have been published since 1987, when the last review of Salmonella meningitis was done . RESULTS: Salmonella typhimurium was the commonest organism reported, and 89.7% of infections occurred in children less than 1 year old . Fluoroquinolones had a cure rate of 88.9%, while the third-generation cephalosporins had a cure rate of 84.6% . Conventional antibiotics (chloramphenicol, ampicillin, and cotrimoxazole) had a cure rate of 41.2%, a relapse rate of 11.8%, and an associated mortality of 44.7% . Treatment with fluoroquinolone and imipenem resulted in no deaths . There were, however, only two cases that were treated with imipenem . CONCLUSION: When Salmonella meningitis is suspected, third-generation cephalosporins, with or without a fluoroquinolone, may be the best option for treatment. Can Vet J, 2003 Apr, 44(4), 319 - 20 Salmonellosis in a herd of beef cows; Pender AB; Two postparturient beef cows in a herd of 30 developed acute enteritis, with pyrexia and bloody diarrhea containing intestinal casts . Salmonella typhimurium phage type 66 was isolated from feces of both animals; both recovered after treatment with tetracycline . A third cow had died without treatment after showing similar signs. Invest Ophthalmol Vis Sci, 2003 May, 44(5), 2184 - 91 Contribution of TNF-alpha to leukocyte adhesion, vascular leakage, and apoptotic cell death in endotoxin-induced uveitis in vivo; Koizumi K et al.; PURPOSE: To investigate the effect of TNF-alpha on leukocyte adhesion, vascular leakage, and apoptotic cell death in endotoxin-induced uveitis (EIU) in the rat . METHODS: EIU was induced in Long-Evans rats by a single footpad injection of lipopolysaccharide (LPS; 350 microg/kg) from Salmonella typhimurium . A single injection of recombinant TNF receptor P75 (etanercept) was given subcutaneously 24 hours before the administration of LPS . Twenty-four hours after administration of LPS, leukocyte adhesion was evaluated in vivo with SLO-acridine orange angiography and ex vivo with concanavalin A lectin staining of retinal flatmounts . Neutrophil activation was quantified by a myeloperoxidase activity assay . Vascular leakage was assessed by Evans blue extravasation . Retinal cell death was assessed with TUNEL staining and quantified with a modified ELISA protocol . Involvement of caspase-3 and -8 was determined by M30 antibody staining, Western blot analysis, and a test for enzymatic activity . RESULTS: Twenty-four hours after the LPS injection, significant increases in leukocyte rolling, adhesion, and activation were observed . In addition, increased levels of apoptosis in the vascular endothelium and the ganglion cell and inner nuclear layers and activation of caspase-8 and -3 were observed . After administration of the TNF-alpha inhibitor, significant reduction in the leukocyte rolling, adhesion, activation, and apoptosis in all the affected layers was observed . The quantitative analysis of vascular leakage revealed a significant decrease after treatment with etanercept . Retinal cell death quantification showed a significant decrease after treatment with the TNF-alpha inhibitor . CONCLUSIONS: Anti-TNF-alpha treatment reduces the LPS-induced increases in leukocyte rolling, adhesion, and vascular leakage in this rat model of inflammatory uveitis . These results suggest the involvement of TNF-alpha in inflammatory uveitis and its potential use as a therapeutic agent in the reduction of ocular inflammation. J Biol Chem, 2003 Jun 27, 278(26), 23624 - 9 Epub 2003 Apr 23. Identification of a sequence in human toll-like receptor 5 required for the binding of Gram-negative flagellin; Mizel SB et al.; Flagellins from Gram-negative bacteria activate inflammatory cells by a toll-like receptor 5 (TLR5)-dependent signaling pathway . We have examined the interaction between flagellin and TLR5 using an in vitro binding assay . Purified recombinant His-tagged flagellin from Salmonella enteritidis bound to TLR5 in detergent lysates from COS-1 cells transiently transfected with a human TLR5 expression plasmid . Flagellins from Salmonella typhimurium and Escherichia coli also bound to TLR5 . The specificity of this interaction was demonstrated by its concentration dependence and lack of TLR5 binding to a biologically inactive form of flagellin or to a His-tagged non-flagellar protein . Flagellin bound to the extracellular domain of TLR5 expressed on the surface of COS-1 cells and to a soluble, monomeric form of the extracellular domain (amino acids 1-636) . Although a TLR5 extracellular domain containing amino acids 1-407 retained flagellin binding activity, binding was not evident with a TLR5 peptide encoding residues 1-386 . Conversely, a peptide containing amino acid residues 386-636 retained flagellin binding . Thus it is likely that amino acids 386-407 is a binding site for flagellin . This sequence contains a putative leucine-rich repeat . These results support the conclusion that flagellin signaling via TLR5 involves a direct interaction between flagellin and a leucine-rich region in TLR5 . We also show that the NH2-terminal 358 amino acids of TLR5 play an important role in its signaling activity . Our results provide, for the first time, a molecular basis for the agonist specificity of a TLR. Indian J Med Res, 2002 Nov, 116, 186 - 91 Effect of Salmonella typhimurium toxin on the expression of rabbit intestinal functions; Chitra et al.; BACKGROUND & OBJECTIVES: Infection by Salmonella Typhimurium is one of the leading causes of intestinal dysfunction, however the underlying mechanism of this effect is largely unknown . Hence the effect of enterotoxin secreted by Salmonella Typhimurium-(S-LT) was studied on D-glucose absorption and brush border enzymes in rabbit ileum . mRNA levels encoding these proteins were also analysed . METHODS: Adult male New Zealand white rabbits were used . The polymyxine B extract of enterotoxin obtained from Salmonella Typhimurium was tested for the presence of enterotoxicity by rabbit ileal loop test . D-glucose uptake by ileal tissue was measured by the tissue accumulation method . Intestinal brush border membranes were isolated and the effect of S-LT on various brush border enzymes studied . RESULTS: S-LT significantly inhibited (P < 0.01) the absorption of Na+ dependent D-glucose uptake but had no effect on Na+ independent sugar uptake in rabbit ileum . The activities of brush border sucrase (72% P < 0.001) and lactase (47% P < 0.01) and alkaline phosphatase (43% P < 0.01) were also significantly reduced in infected animals as compared to the controls . Northern blot analysis revealed that mRNA levels encoding Na+ glucose co-transporter (SGLT1), brush border lactase and sucrase activities were unaffected in Salmonella infected rabbit ileal loops . INTERPRETATION & CONCLUSION: The findings suggest that the intestinal dysfunctions observed in Salmonella infection are unrelated to mRNA expression encoding Na+ glucose co-transporter and brush border enzyme proteins in rabbit ileum. J Dent Res, 2003 May, 82(5), 367 - 71 Biocompatibility of hydroxylated metabolites of BISGMA and BFDGE; Kostoryz EL et al.; Unpolymerized dental monomers can leach out into the oral biophase and are bioavailable for metabolism . We hypothesize that metabolites would be less toxic than parent monomers . We first identified the formation of metabolites from bisphenol F diglycidyl ether (BFDGE) and Bisphenol A glycidyl methacrylate (BISGMA) after their exposure to liver S9 fractions . Then, the metabolites and parent compounds were subjected to in vitro cytotoxicity, mutagenicity, and estrogenicity studies . Bisphenol A bis(2,3-dihydroxypropyl) ether and bisphenol F bis(2,3-dihydroxypropyl) ether were the hydroxylated metabolites of BISGMA and BFDGE, respectively . Cytotoxicity against L929 cells showed that the metabolites were significantly (p < 0.05) less cytotoxic than the parent monomers . Only BFDGE was mutagenic in the Ames assay with strain TA100 of Salmonella typhimurium . Parent and metabolite compounds did not stimulate estrogen-dependent MCF-7 cell proliferation above solvent controls . These results indicated that the hydroxylated metabolites were non-mutagenic, non-estrogenic, and less cytotoxic than their parent monomers. Microb Drug Resist, 2003 Spring, 9(1), 25 - 32 Topoisomerase IV mutations in quinolone-resistant salmonellae selected in vitro; Hansen H et al.; The development of high-level fluoroquinolone resistance has rarely been observed in salmonellae and, in contrast to other Gram-negative bacteria mutations affecting topoisomerase IV, a known secondary target of quinolones in Escherichia coli has not been described except for one recent report . The present study used quinolone-susceptible field isolates representing epidemiologically relevant serovars and phage types Salmonella Hadar and Salmonella Typhimurium DT104 and DT204c to select fluoroquinolone-resistant mutants in vitro . Three selection steps were necessary to obtain high-level fluoroquinolone-resistant mutants (MICCip > or = 8 microg/ml) . All first-step mutants examined had a single gyrA mutation (affecting either Ser83 or Asp87) . Additional topoisomerase mutations affecting gyrA (Asp87), gyrB (Ser464), and parC (Gly78) were detected in second- and third-step mutants . Introducing into the respective mutants the corresponding plasmid-coded quinolone-susceptible allele of either gyrA, gyrB, or parC resulted in reduction of quinolone resistance, indicating a role for these mutations in quinolone resistance . In the presence of an inhibitor of RND-type efflux pumps, the susceptibilities to ciprofloxacin and chloramphenicol of second- and third-step mutants increased by two to four serial dilution steps, providing evidence that an efflux-mediated resistance mechanism contributes to the development of high-level fluoroquinolone resistance in salmonellae. Clin Neurophysiol, 2003 Mar, 114(3), 581 - 8 Safety of the magnetic field generated by a neuronal magnetic stimulator: evaluation of possible mutagenic effects; Charlet de Sauvage R et al.; OBJECTIVE: The possible mutagenicity of a magnetic stimulus was checked using the Ames test with Salmonella typhimurium TA98 and TA100 as tester strains . METHODS: Samples of these bacteria were exposed to a pulsed magnetic field, on the order of 1 T . The magnetic pulses were generated by a neuronal magnetic stimulator with a flat coil . The magnetic stimulus was a continuous sequence of slightly damped half sinusoids at a rate of 5 pulses/s . Exposure times were 2-5 and 15 min . Exposure position was such as to maximise the magnetic field and minimise the induced electric field . Room temperature was maintained at 28.5 +/- 0.5 degrees C and the temperature was measured inside the samples . RESULTS: None of the exposure conditions showed any increase in mutation in either of the two bacterial strains . CONCLUSIONS: These results are discussed in comparison with effects found in the literature . The magnetic stimulation used under the conditions of this study does not appear to have mutagenic effects . This does not apply to cases where both strong electric and magnetic fields are present. Natl Toxicol Program Tech Rep Ser, 1989 Sep, 355, 1 - 176 NTP Toxicology and Carcinogenesis Studies of Diphenhydramine Hydrochloride (CAS No . 147-24-0) in F344/N Rats and B6C3F1 Mice (Feed Studies); National Toxicology Program ; Diphenhydramine hydrochloride is a widely used antihistaminic drug in human and veterinary medicine . Toxicology and carcinogenesis studies were conducted by feeding diets containing USP-grade diphenhydramine hydrochloride (greater than 99% pure) to groups of F344/N rats and B6C3F1 mice of each sex for 14 days, 13 weeks, or 2 years . Genetic toxicology studies were conducted in Salmonella typhimurium, mouse L5178Y cells, and Chinese hamster ovary (CHO) cells . Fourteen-Day and Thirteen-Week Studies: In the 14-day studies, dietary concentrations ranged from 620 to 10,000 ppm for rats and from 310 to 5,000 ppm for mice . All rats that received diets containing 10,000 ppm and 9/10 rats that received diets containing 5,000 ppm died before the end of the studies . The final mean body weights of rats receiving 1,250 or 2,500 ppm were 12%-13% or 30%-34% lower than those of controls . Feed consumption by rats at the three highest concentrations was more than 30% less than that by controls . All mice receiving 5,000 ppm, 4/5 males and 4/5 females receiving 2,500 ppm, and 4/5 males receiving 1,250 ppm died before the end of the studies . The final mean body weights of mice that received 1,250 or 2,500 ppm were lower than the initial weights . All dosed rats and mice were hyperactive and sensitive to sound and/or touch . In the 13-week studies, dietary concentrations of diphenhydramine hydrochloride ranged from 156 to 2,500 ppm for rats and from 78 to 1,250 ppm for mice . All rats lived to the end of the studies . The final mean body weights of rats receiving 1,250 or 2,500 ppm were about 15% or 35% lower than those of controls . The final mean body weight of female rats receiving 625 ppm was 9% lower than that of controls . Increased activity was observed for all male and female rats receiving 1,250 and 2,500 ppm . Cytoplasmic vacuolization of the liver, characteristic of fat accumulation, was observed in male and female rats receiving 313-2,500 ppm . The severity of this change increased with increased dose . For mice, 1/10 males receiving 313 ppm, 2/10 males receiving 625 ppm, and 8/10 males receiving 1,250 ppm died before the end of the studies . The final mean body weights of mice that received 625 or 1,250 ppm were about 9% or 16% lower than those of controls . No compound-related histopathological effects were observed in mice . Based on the mortality and body weight effects of diphenhydramine hydrochloride in the short-term studies, dietary concentrations selected for the 2-year studies were 0,313, and 635 ppm diphenhydramine hydrochloride for male rats and 0, 156, and 313 ppm for female rats and male and female mice . Body Weight and Survival in the Two-Year Studies: Mean body weights of dosed and control rats were similar throughout the studies, and mean body weights of dosed mice were 3%-13% lower than those of controls throughout most of the studies . No significant differences in survival were observed between any groups of rats or mice of either sex (male rats: control, 29/50; low dose, 32/50; high dose, 24/50; female rats: 35/50; 32/50; 36/50; male mice: 29/50; 30/50; 24/48; female mice: 37/50; 39/50; 32/50) . The estimated average daily feed consumption by dosed rats and dosed mice was similar to that by controls . The average amount of diphenhydramine hydrochloride consumed per day was approximately 13 or 27 mg/kg for low dose or high dose male rats, 7 or 15 mg/kg for low dose or high dose female rats, and 21 or 46-47 mg/kg for low dose or high dose male and female mice . Nonneoplastic and Neoplastic Effects in the Two-Year Studies: For three high dose male rats, astrocytomas were found in brain sections taken by routine sampling procedures . Gliomas, containing neoplastic astrocytes and oligodendrocytes, were found in one control and one additional high dose male rat . The incidence of glial cell tumors in high dose male rats (4/50) exceeded the highest incidence in historical controls in the Program (2/50) . The historical incidence of glial cell tumors is less than 0.7% in approximately 2,000 untreated control male F344/N rats . Three addiless than 0.7&percnt; in approximately 2,000 untreated control male F344/N rats . Three additional sections of brain were prepared from the residual fixed tissues of each male and female rat . One additional astrocytoma in a high dose male rat and one astrocytoma in a high dose female rat were observed in these sections . Adenomas of the anterior pituitary gland in female rats occurred with a significant positive trend; the incidences in low dose male and high dose female rats were marginally greater than those in controls (male: control, 11/49; low dose, 21/50; high dose, 14/49; female: 23/50; 26/50; 35/50) . The incidence of alveolar/bronchiolar adenomas in low dose male rats was slightly greater than that in controls (0/49; 5/50; 3/50) . The incidences of alveolar/bronchiolar adenomas or carcinomas (combined) in dosed male rats were not significantly different from that in controls (1/49; 6/50; 5/50) but exceeded the highest incidence in historicalcontrols (4/49) . The historical incidence of alveolar/bronchiolar neoplasms in untreated control male F344/N rats is approximately 2.2&percnt; . Adenomatous hyperplasia of the lung was not increased in incidence in dosed male rats compared with controls . The incidences of granulomas of the liver were increased in dosed rats (male: 0/49; 3/50; 4/50; female: 8/50; 15/49; 18/50) . At no site were the incidences of neoplastic lesions in dosed mice considered to be compound related . Cytoplasmic vacuolization (fatty metamorphosis) of the liver was observed at an increased incidence in high dose female mice (0/49; 1/49; 8/49) . Genetic Toxicology: Diphenhydramine hydrochloride was not mutagenic in S . typhimurium strains TA98, TA100, TA1535, or TA1537 when tested in either the presence or absence of exogenous metabolic activation . Exposure to this chemical did not induce trifluorothymidine (Tft) resistance in mouse L5178Y lymphoma cells with or without metabolic activation . In cytogenetic tests with cultured CHO cells, diphenhydramine hydrochloride induced chromosomal aberrations in the absence, but not the presence, of exogenous metabolic activation (S9); no induction of sister chromatid exchanges (SCEs) was observed in these cells with or without S9 . Conclusions: Under the conditions of these 2-year feed studies, there was equivocal evidence of carcinogenic activity of diphenhydramine hydrochloride for male F344/N rats, based on marginally increased incidences of uncommon brain neoplasms (astrocytomas or gliomas) and of alveolar/bronchiolar neoplasms . There was equivocal evidence of carcinogenic activity for female F344/N rats, based on a marginal increase in the incidence of pituitary gland adenomas . There was no evidence of carcinogenic activity for male or female B6C3F1 mice fed diets containing 156 or 313 ppm diphenhydramine hydrochloride . Synonyms: 2-diphenylmethoxy-N,N-dimethylethanamine hydrochloride; 2-(benzhydryloxy)-N,N-dimethylethylamine hydrochloride; b-dimethylaminoethyl benzhydryl ether hydrochloride; benzhydramine hydrochloride Trade Names: Alleran; Benadryl Natl Toxicol Program Tech Rep Ser, 1990 Jan, 347, 1 - 165 NTP Toxicology and Carcinogenesis Studies of d-Limonene (CAS No . 5989-27-5) in F344/N Rats and B6C3F1 Mice (Gavage Studies); National Toxicology Program ; Toxicology and carcinogenesis studies of d-limonene, a naturally occurring monoterpene found in many volatile oils, especially in citrus oils, were conducted because of its widespread use as a flavor and fragrance additive for food and household cleaning products and its increasing use as an industrial solvent . The d-limonene used in these studies was more than 99% pure and was administered in corn oil by gavage . Short-term studies were conducted in F344/N rats and B6C3F1 mice to identify toxic effects and affected sites and to help establish doses for the 2-year studies . Genetic toxicology studies were conducted in Salmonella typhimurium, mouse L5178Y cells, and Chinese hamster ovary (CHO) cells . The doses selected for the 16-day studies ranged from 413 to 6,600 mg/kg for both rats and mice; deaths and reduction in body weight gain occurred at the two highest doses . No compound-related clinical signs or histopathologic lesions were observed in any of the surviving dose groups . In the 13-week studies, doses of d-limonene ranged from 150 to 2,400 mg/kg for rats and from 125 to 2,000 mg/kg for mice . Deaths occurred in the high dose group of each species and sex . Greater than 10% reductions in body weight gain were observed in the two highest dose groups of male rats and male mice and the high dose female rats . Rough hair coats and decreased activity were observed at the two highest doses in both rats and mice . There were no chemical-related histopathologic lesions in female rats or in mice of either sex . A compound-related increased severity of nephropathy was observed in the kidney of male rats . This lesion was characterized by degeneration of epithelial cells in the convoluted tubules, granular casts in the outer stripe of the outer medulla, and epithelial regeneration . These lesions have been described as reasonably characteristic of the hyaline droplet nephropathy that is associated with an accumulation of liver-generated a2u-globulin in the cytoplasm of tubular epithelial cells . Two-year studies of d-limonene were conducted by administering 0, 75, or 150 mg/kg d-limonene in corn oil by gavage to groups of 50 F344/N male rats, 5 days per week for 103 weeks; groups of 50 female F344/N rats were administered 0, 300, or 600 mg/kg . These doses were selected based on compound-related, potentially life-threatening kidney lesions observed in males at 300 mg/kg and higher and on the large number of deaths of female rats at 2,400 mg/kg . Groups of 50 male B6C3F1 mice were administered 0, 250, or 500 mg/kg according to the same schedule; groups of 50 female B6C3F1 mice were administered 0, 500, or 1,000 mg/kg . These doses were selected based on the deaths observed for both male and female mice at 2,000 mg/kg during the 13-week studies and the body weight depression in male mice at 1,000 mg/kg and higher . Mean body weights of rats dosed with d-limonene were similar to those of vehicle controls throughout the studies . Survival of the high dose female rats after week 39 and of the vehicle control male rats after week 81 was significantly reduced (survival at week 104-- male: vehicle control, 29/50; low dose, 33/50; high dose, 40/50; female: 42/50; 40/50; 26/50) . Mean body weights of dosed and vehicle control male mice were similar throughout the studies . Mean body weights of high dose female mice were notably lower than those of the vehicle controls after week 28 . Survival of the low dose group of male mice was significantly lower than that of vehicle controls at the end of the study (33/50; 24/50; 39/50) . No difference in survival was observed between vehicle control and dosed female mice (43/50; 44/50; 43/50) . In the 2-year studies, the kidney was confirmed as the primary target organ for chemically related lesions . No lesions were observed in female rats . For males, the nonneoplastic lesions included exacerbation of the age-related nephropathy, linear deposits of mineral in the renal medulla and papilla, and focal hyperplasia of the transitional epithelium overlying the renal papilla . Uncommon tubular cell adenomas and adenocarc and adenocarcinomas of the kidney also occurred in dosed male rats, and this effect was supported by a dose-related increased incidence of tubular cell hyperplasia, as shown in the table below . INCIDENCES OF MALE RATS WITH RENAL LESIONS IN THE TWO-YEAR GAVAGE STUDY OF d-LIMONENE Site/Lesion Vehicle Control 75 mg/kg 150 mg/kg Renal papilla Mineralization 7/50 43/50 48/50 Epithelial hyperplasia 0/50 35/50 43/50 Kidney Tubular cell hyperplasia 0/50 4/50 7/50 Tubular cell adenoma 0/50 4/50 8/50 Tubular cell adenocarcinoma 0/50 4/50 3/50 In subsequent 21-day studies, male and female F344/N rats were administered d-limonene at doses ranging from 75 to 1,200 mg/kg . Microscopic examination of the kidney sections from these rats indicated a compound-related increase in intracytoplasmic granules in the proximal convoluted tubules of dosed male rats but not of female rats . The granules were shown to contain a2u-globulin by an immunohistochemical strain . a2u-Globulin was shown to be increased in kidney homogenates from dosed male rats by an ELISA test . In mice, no chemically related increases in neoplasms were observed . The incidence of neoplasms of the anterior pituitary gland in high dose female mice was lower than that in vehicle controls (adenomas or carcinomas, combined:vehicle control, 12/49; high dose, 2/48) . Cells with an abnormal number of nuclei (8/49; 32/50) and cytomegaly (23/49; 38/50) were observed in the liver of high dose male mice . Genetic Toxicology: d-Limonene was not mutagenic in four strains of S . typhimurium (TA98, TA100, TA1535, or TA1537), did not significantly increase the number of trifluorothymidine (Tft)-resistant cells in the mouse L5178Y/TK&plusmn; assay, and did not induce chromosomal aberrations or sister chromatid exchanges (SCEs) in cultured CHO cells . All assays were conducted in the presence and absence of exogenous metabolic activation . Conclusions: Under the conditions of these 2-year gavage studies, there was clear evidence of carcinogenic activity of d-limonene for male F344/N rats, as shown by increased incidences of tubular cell hyperplasia, adenomas, and ad