Appl Environ Microbiol, 1996 Dec, 62(12), 4675 - 7 Enrichment of mixed cultures capable of aerobic degradation of 1,2-dibromoethane; Freitas dos Santos LM et al.; 1,2-dibromoethane (DBE) is a common environmental contaminant; it is potentially carcinogenic and has been detected in soil and groundwater supplies . Most of the biodegradation studies to date have been performed under anaerobic conditions or in the context of soil remediation, where the pollutant concentration was in the parts per billion range . In this work a mixed bacterial culture capable of complete aerobic mineralization of concentrations of DBE up to 1 g liter(-1) under well-controlled laboratory conditions was enriched . In order to verify biodegradation, formation of biodegradation products as well as the disappearance of DBE from the biological medium were measured . Complete mineralization was verified by measuring stoichiometric release of the biodegradation products . This mixed culture was found to be capable of degrading other halogenated compounds, including bromoethanol, the degradation of which has not been reported previously. Appl Environ Microbiol, 1996 Dec, 62(12), 4352 - 60 Biodegradation of dimethylsilanediol in soils; Sabourin CL et al.; The biodegradation potential of {14C}dimethylsilanediol, the monomer unit of polydimethylsiloxane, in soils was investigated . Dimethylsilanediol was found to be biodegraded in all of the tested soils, as monitored by the production of 14CO2 . When 2-propanol was added to the soil as a carbon source in addition to {14C}dimethylsilanediol, the production of 14CO2 increased . A method for the selection of primary substrates that support cometabolic degradation of a target compound was developed . By this method, the activity observed in the soils was successfully transferred to liquid culture . A fungus, Fusarium oxysporum Schlechtendahl, and a bacterium, an Arthrobacter species, were isolated from two different soils, and both microorganisms were able to cometabolize {14C}dimethylsilanediol to 14CO2 in liquid culture . In addition, the Arthrobacter sp . that was isolated grew on dimethylsulfone, and we believe that this is the first reported instance of a microorganism using dimethylsulfone as its primary carbon source . Previous evidence has shown that polydimethylsiloxane is hydrolyzed in soil to the monomer, dimethylsilanediol . Now, biodegradation of dimethylsilanediol in soil has been demonstrated. FEMS Microbiol Lett, 1996 Nov 15, 145(1), 125 - 9 Biodegradation of 4-chlorophenol via a hydroquinone pathway by Arthrobacter ureafaciens CPR706; Bae HS et al.; A newly isolated Arthrobacter ureafaciens, strain CPR706, could degrade 4-chlorophenol via a new pathway, in which the chloro-substituent was eliminated in the first step and hydroquinone was produced as a transient intermediate . Strain CPR706 exhibited much higher substrate tolerance and degradation rate than other strains that degraded 4-chlorophenol by the hydroxylation at the second carbon position to form chlorocatechol . Strain CPR706 could also degrade other para-substituted phenols (4-nitro-, 4-bromo-, 4-iodo-, and 4-fluoro-phenol) via the hydroquinone pathway. Mycoses, 1996 Nov-Dec, 39(11-12), 483 - 7 Biodegradation of wool by Trichophyton simii and Aspergillus niger; Shrivastava JN et al.; The amount of protein released into liquid culture medium and weight loss were taken as measures of wool degradation by Trichophyton simii and Aspergillus niger . Protein released into the culture medium was observed to be greater after T . simii treatment than after A . niger treatment . Sulphitolysis was shown by T . simii, whereas it was absent in the case of A . niger, pH was found to be alkaline with an increase in soluble protein in the culture medium in the case of both uniculture and dual culture . However, both the weight loss of wool and the amount of protein released were significantly reduced when both fungi were allowed to attack the substrate . The behaviour of these fungi in dual culture reflects their antagonistic activities. J Chem Inf Comput Sci, 1996 Nov-Dec, 36(6), 1061 - 6 Designing molecules with specific properties from intercommunicating hybrid systems; Devillers J; The concept that computers can be creative in designing new molecules is now being actively explored . Our work has been aimed at developing an intercommunicating hybrid system using a genetic algorithm and a backpropagation neural network model for solving the general problem of designing molecules with specific properties . A case study dealing with biodegradation modeling is presented . The usefulness of the intercommunicating hybrid systems in QSAR and drug design is emphasized. Chemosphere, 1996 Nov, 33(10), 2045 - 56 Biodegradation of three substituted phenylurea herbicides (chlortoluron, diuron, and isoproturon) by soil fungi . A comparative study; Vroumsia T et al.; As a part of a study conducted on the fate of xenobiotics in the environment, a selection of 90 strains of micromycetes, mostly isolated from soil and belonging to various taxonomic groups, have been cultivated in liquid synthetic medium with chlortoluron (100 mg.L-1), diuron (20 mg.L-1), and isoproturon (100 mg.L-1) for 5 days . Evaluation of the chemicals in the culture media was made by HPLC . Our results show a wide variation not only with taxonomic groups but also with the species, and with the tested chemicals . On the whole, 4, 7, and 11% of the strains depleted respectively chlortoluron, diuron, and isoproturon, at 50% or over . Rhizoctonia solani was the only strain that depleted each of the 3 substituted phenylureas over 70%, nevertheless, the growth of this fungus was slightly inhibited by diuron . The very fast disappearance of the chemicals from the culture media was only due to biotic phenomena, as no adsorption occurred on the fungal biomass . So, depletion translated a real biodegradation of the tested substrates. Biomaterials, 1996 Nov, 17(22), 2173 - 8 Biodegradation of synthetic biphasic calcium phosphate by human monocytes in vitro: a morphological study; Benahmed M et al.; Biodegradation processes (both intra- and extracellular) occur immediately after implantation of calcium phosphate (CaP) ceramics . Monocytes and macrophages, among the first cells to appear in wound healing, are largely implicated in phagocytosis and may be involved in CaP degradation because of their sensitivity to secreted cytokines . We tested the behaviour of human monocytes placed on the surface of hydroxyapatite (HA) and biphasic calcium phosphate (BCP) tablets in the presence of vitamin D3 (VD3) and interferon gamma (INF gamma) . After short-term culture (6 days), morphological events were observed in histological and scanning electron microscopy studies, and degradation lacunae were characterized . There were cell prints but no pits on the HA surface, but pits appeared near cells on the BCP surface . Preincubation of biomaterial in culture medium was essential . Variations in cell morphology were observed in different culture types . In the presence of VD3, degradation was greater than in the control, and cells were more polarized and rounded . With INF gamma, cells were extensively spread out on the sample surface, and the biomaterial seemed to be extracted from the surface by cells . Thus, monocytes are clearly influenced by soluble factors (vitamins, cytokines) and could be key cells in initiating the degradation of biomaterial. J Biomed Mater Res, 1996 Nov, 32(3), 383 - 9 Self-setting, bioactive, and biodegradable TTCP-DCPD apatite cement; Hamanishi C et al.; Tetracalcium phosphate-dicalcium phosphate dihydrate self-setting apatite cement mixed with low-crystallized seed hydroxyapatite is similar to the host bone in degree of crystallinity . The bonding strength of this cement with hydroxyapatite-coated titanium rods was twice that with noncoated titanium and four times that with stainless steel . Histologically, TTCP-DCPD apatite cement incorporated into the tibia of rabbits were degraded, absorbed, and replaced by the normal body trabeculae rapidly . The mechanical strength of the cement disk intercalated into a gap made in the rabbit tibiae increased to 73% of that of the normal tibia at 10 weeks concurrently with the decrease in bone mineral density of the disk toward that of the normal tibia, in which bony replacement of the disk was observed also histologically . These bioactive and biodegradative characters of this cement are due to the similarity of its degree of crystallinity to that of the host bone, and could expand its clinical applications. J Biomed Mater Res, 1996 Nov, 32(3), 321 - 31 In vivo testing of crosslinked polyethers . II . Weight loss, IR analysis, and swelling behavior after implantation; Pol BJ et al.; As reported in Part I ("In vivo testing of crosslinked polyethers . I . Tissue reactions and biodegradation," J . Biomed . Mater . Res., this issue, pp . 307-320), microscopical evaluation after implantation of crosslinked (co)polyethers in rats showed differences in the rate of biodegradation, depending on the presence of tertiary hydrogen atoms in the main chain and the hydrophilicity of the polyether system . In this article (Part II) the biostability will be discussed in terms of weight loss, the swelling behavior, and changes in the chemical structure of the crosslinked polyethers after implantation . The biostability increased in the order poly(POx) < poly(THF-co-OX) < poly(THF) for the relatively hydrophobic polyethers . This confirmed our hypothesis that the absence of tertiary hydrogen atoms would improve the biostability . On the other hand, signs of biodegradation were observed for all polyether system studied . Infrared surface analysis showed that biodegradation was triggered by oxidative attack on the polymeric chain, leading to the formation of carboxylic ester and acid groups . It also was found that in the THF-based (co)polyethers, alpha-methylene groups were more sensitive than beta-methylene groups . For a hydrophilic poly(THF)/PEO blend, an increase in surface PEO content was found, which might be due to preferential degradation of the PEO domains. J Biomed Mater Res, 1996 Nov, 32(3), 307 - 20 In vivo testing of crosslinked polyethers . I . Tissue reactions and biodegradation; Pol BJ et al.; The in vivo biocompatibility and biodegradation of cross-linked (co)polyethers with and without tertiary hydrogen atoms in the main chain and differing in hydrophilicity were studied by means of subcutaneous implantation in rats . After 4 days, 1 month, and 3 months postimplantation, the tissue reactions and interactions were evaluated by light microscopy (LM) and transmission electron microscopy (TEM) . Poly(tetrahydrofuran) (poly(THF)), poly(propylene oxide) (poly(POx)), and poly(tetrahydrofuran-co-oxetane) (poly-(THF-co-OX)) were tested as relatively hydrophobic polyethers, and poly(ethylene oxide) (PEO) and a poly(THF)/ PEO blend were used as more hydrophilic materials . In general, all polyethers showed good biocompatibility with respect to tissue reactions and interactions, with low neutrophil and macrophage infiltration, a quiet giant cell reaction, and formation of a thin fibrous capsule . For the relatively hydrophobic polyethers studied, the biostability increased in the order poly(POx) < poly(THF-co-OX) < poly(THF), probably indicating that the absence of tertiary hydrogen atoms has a positive effect on the biostability . Concerning the more hydrophilic materials, crosslinked PEO showed the highest rate of degradation, probably due to the mechanical weakness of the hydrogel in combination with the highest presence of giant cells as a result of the high porosity . A frayed surface morphology was observed after implantation of the crosslinked poly(THF)/PEO blend, which might be due to preferential degradation of PEO domains. J Environ Sci Health B, 1996 Nov, 31(6), 1253 - 66 Effect of Ozonation on the biodegradability of atrazine in GAC columns; Huang CM et al.; The biodegradation of atrazine as influenced by preozonation was studied in biological GAC columns . Metabolism of isopropyl-14C atrazine produced more 14CO2 than ring-UL-14C atrazine, indicating dealkylation was more rapid than ring cleavage . Preozonation increased mineralization of ring-UL-14C atrazine and, consequently, enhanced the performance of GAC columns . Sixty-two percent of the influent atrazine was converted to 14CO2 in columns that received ozonated atrazine and ozonated surface water, while 50% of the influent atrazine was converted to 14CO2 in columns that received untreated atrazine and ozonated surface water, and only 38% of the influent atrazine was converted to 14CO2 in columns with untreated influent. J Biomater Appl, 1996 Oct, 11(2), 182 - 257 Biodegradable polyurethanes: biodegradable low adherence films for the prevention of adhesions after surgery; Rehman IU; Adhesions commonly occur after internal disease or surgery . The natural healing response leads to the formation of vascular and avascular adhesions after inflammatory diseases and surgical interventions . A barrier film could be incorporated during surgery between layers of tissues that must not adhere to one another . The film would be biodegradable so that it disappears over a period of time, and would ideally be two sided, allowing relative movement at that interface, while being firmly anchored on the opposite side to prevent displacement . Polyesterurethane-polydimethylsiloxane graft polymers are synthesised . Chemical characterisation of the polymer is performed by using Fourier transform infrared spectroscopy and gel permeation chromatography . In vitro hydrolytic degradation is carried out in which films are immersed at 37 degrees C in alkaline solution . Degradation is assessed by tensile testing as a function of time to determine the degradation of mechanical strength, infrared spectroscopy, and mass loss . A titration method is also used to determine quantitatively the hydrolytic degradation . In order to study the adhesions of films, an in-vitro model based on a gelatine test, which is simple and rapid, is described . Suitable candidate films investigated from the in-vitro work are subjected to in vivo tests for both biodegradation and their ability to prevent adhesion. J Biomater Appl, 1996 Oct, 11(2), 121 - 34 Resistance to biodegradative stress cracking in microporous vascular access grafts; Carson RJ et al.; Degradative cracking, more commonly known as "environmental stress cracking" (ESC) has been observed in many implanted polyetherurethane elastomers . This phenomenon has been attributed to biochemical and cellular interactions at the surface of the implanted material causing polymer chain cleavage . This may result in surface fissuring followed by the deep cracking associated with considerable biodegradation of the polymer, resulting in loss of mechanical strength and the formation of aneurysms in an in vivo situation . These cracking effects are believed to be due to mechanical stress combined with the oxidising actions of macrophages and giant cells, as surface cracking has been observed to occur directly under adherent macrophages on a polyetherurethane implant . These cells form part of the body's immune response which uses enzymes and reactive oxygen species (O2, O2-, and HO . and H2O2) to degrade foreign material . We describe a modification of an in vitro test method developed by Zaho et al . {1} using glass wool and a Hydrogen Peroxide/Cobalt (II) Chloride (H2O2/CoCl2) mixture to replicate the oxidising effects of macrophages in vivo . The modifications were made to establish a routine testing system for resistance to biodegradation which could be used to screen a range of polymers designed for use in microporous vascular grafts . The grafts are pre-stressed by a method devised by Stokes et al . {2} where each graft is stretched to a predetermined elongation over a mandrel and the strain is fixed by tying PTFE tape around each end of the mandrel. Biomaterials, 1996 Oct, 17(20), 1945 - 70 Interfacial shear strength and histology of plasma sprayed and sintered hydroxyapatite implants in vivo; Wang S et al.; The interfaces of bone with sintered hydroxyapatite (SHA) and plasma sprayed hydroxyapatite-coated (HAC) implants in the femora of six dogs were examined by light microscopy, scanning electron microscopy, energy dispersive X-ray analysis, and push-out tests . The results demonstrated that there was no significant difference at 12 and 24 weeks after insertion between the interfacial shear strengths with bone for the two types of implants, however, the histological characteristics of the bone around the plasma sprayed HA could be distinguished from that of the sintered HA . The HAC implants showed an early surface biodegradation as compared with the SHA implants . The observed differences in the interfacial zones may be attributed to different bone cell activities and variations in the dynamics of bone formation, possibly resulting from a higher level of dissolution/reprecipitation along the plasma sprayed HA surface. Arch Environ Contam Toxicol, 1996 Oct, 31(3), 410 - 9 Responses of embryonic and larval inland silversides, Menidia beryllina, to a water-soluble fraction formed during biodegradation of artificially weathered Alaska North Slope crude oil; Middaugh DP et al.; Weathered Alaska North Slope crude oil (ANS 521) was stirred for 2 and 14 days in 20 per thousand salinity sterile seawater or for 14 days in seawater with nutrients and a group of three (GO3) microorganisms from Prince William Sound, Alaska, that were capable of biodegrading hydrocarbons . A total of 0.65 and 0.69 mg/L water soluble fraction (WSF) of neutral fraction hydrocarbons was recovered from the 2- and 14-day stirred sterile systems, respectively . In comparison, a total of 7.5 mg/L WSF neutral fraction hydrocarbons was recovered from systems containing ANS 521 that were stirred and biodegraded by the GO3 microbes for 14 days . Toxicity/teratogenicity tests were conducted with neutral fraction hydrocarbons recovered from the sterile and biodegraded systems using embryonic inland silversides, Menidia beryllina . Hydrocarbons from the sterile systems did not cause statistically significant teratogenic responses at concentrations of 1%, 10%, and 100% (w/v) of recovered fractions (redissolved in 20 per thousand salinity sterile seawater) . Counts of heart contraction rates were significantly lower (alpha</=0.05) at the 100% WSF concentration of hydrocarbons on days 5 and 6 of embryogenesis . In contrast, recovered and redissolved neutral fraction hydrocarbons from ANS 521, that were biodegraded for 14 days, caused statistically significant (alpha</=0.05) teratogenic responses at the 1, 10, and 100% WSF concentrations . Measurement of heart contraction rates showed statistically significant (alpha</=0.05) reductions at the 100% WSF concentration on days 2 through 6 of embryogenesis, compared to controls. Arch Environ Contam Toxicol, 1996 Oct, 31(3), 319 - 28 Determination of organotin compounds in the foodweb of a shallow freshwater lake in the Netherlands; Stab JA et al.; An extensive study on the presence of nine organotin compounds (OTs) in a freshwater foodweb was made, using newly developed analytical procedures in order to obtain insight in accumulation and degradation processes . Tributyltin (TBT), Triphenyltin (TPT) and their degradation products were detected . Zebra mussels, eel, roach, bream, pike, perch, and pike perch and cormorant showed high OT body concentrations . At the lower trophic levels, phenyltin concentrations were higher in benthic species while butyltin concentrations were higher in pelagic species . This indicates that TBT is passed on primarily via the water, while TPT is passed on to a larger extent via the sediment . At the higher trophic levels, net bioaccumulation of TPT was greater than that of TBT, resulting in relatively higher TPT concentrations . High concentrations of biodegradation products of TBT, but not of TPT, were found in the livers of fish and birds, which indicates that TBT is more easily metabolized than TPT . A comparison with literature data of fish lethal body concentrations revealed that fish in the field may be endangered . With birds, the highest concentrations of OTs were present in liver and kidney and not in subcutaneous fat, which confirms that OTs accumulate via different mechanisms than traditional lipophilic compounds . As a whole the OT concentrations found in the foodweb may be considered to be quite alarming. Circulation, 1996 Oct 1, 94(7), 1690 - 7 Marked inflammatory sequelae to implantation of biodegradable and nonbiodegradable polymers in porcine coronary arteries; van der Giessen WJ et al.; BACKGROUND: With the thrombogenic tendency and permanent implant nature of metallic stents, synthetic polymers have been proposed as candidate materials for stents and local drug delivery designs . We investigated the biocompatibility of several synthetic polymers after experimental placement in the coronary artery . METHODS AND RESULTS: Five different biodegradable polymers (polyglycolic acid/polylactic acid {PGLA}, polycaprolactone {PCL}, polyhydroxybutyrate valerate {PHBV}, polyorthoester {POE}, and polyethyleneoxide/polybutylene terephthalate {PEO/ PBTP}) and three nonbiodegradable polymers (polyurethane {PUR}, silicone {SIL}, and polyethylene terephthalate {PETP}) were tested as strips deployed longitudinally across 90 degrees of the circumferential surface of coil wire stents . Appropriately sized polymer-loaded stents were implanted in porcine coronary arteries of 2.5- to 3.0-mm diameter . Four weeks after implantation, stent patency was assessed by angiography followed by microscopic examination of the coronary arteries . The biodegradable PCL, PHBV, and POE and the nonbiodegradable PUR and SIL evoked extensive inflammatory responses and fibrocellular proliferation (thickness of tissue response: 0.79 +/- 0.22, 1.12 +/- 0.01, 2.36 +/- 0.60, 1.24 +/- 0.36, and 1.43 +/- 0.15 mm, respectively) . Less but still severe responses were observed for the biodegradable PGLA and PEO/PBTP (0.46 +/- 0.18 and 0.61 +/- 0.23 mm, respectively) and for the nonbiodegradable PETP (0.46 +/- 0.11 mm) . CONCLUSIONS: An array of both biodegradable and nonbiodegradable polymers has been demonstrated to induce a marked inflammatory reaction within the coronary artery with subsequent neointimal thickening, which was not expected on the basis of in vitro tests . The observed tissue response may be attributable to a combination of parent polymer compound, biodegradation products, and possibly implant geometry. J Histochem Cytochem, 1996 Oct, 44(10), 1131 - 40 Ultrastructural study of degradation of calcium phosphate ceramic by human monocytes and modulation of this activity by HILDA/LIF cytokine; Benahmed MD et al.; Biodegradation of ceramics in vivo is achieved essentially by monocytes and multinuclear cells (osteoclasts) . Monocytes are the key element in this process because they intervene first at the biomaterial implantation site during inflammatory reaction . In this work, in vitro studies were conducted on an ultrastructural scale to determine the specific behavior of these cells with regard to a calcium phosphate (CaP) ceramic . Two types of phagocytosis were observed when cells came into contact with the biomaterial: either CaP crystals were taken up alone and then dissolved in the cytoplasm after disappearance of the phagosome membrane or they were incorporated together with large quantities of culture medium, in which case dissolution occurred after the formation of heterophagosomes . Phagocytosis of CaP coincided with autophagy and the accumulation of residual bodies in the cells . Addition of HILDA/LIF factor to these cultures induced a very marked decrease in phagocytotic activity directed at the capture of CaP crystals and culture medium . Autophagy was reduced, and residual bodies were rare or absent . This study specifies the role of monocytes in CaP biodegradation and demonstrates for the first time that HILDA/LIF has a biological effect on this cell line. Chemosphere, 1996 Oct, 33(7), 1247 - 59 A respirometer with improved sensitivity for ready biodegradation testing; Hales SG et al.; In this paper we describe a respirometry system with improved sensitivity, that was used to test materials at concentrations down to 3 mg C/l . Data obtained with this system, operating under the conditions of the OECD ready biodegradability tests 301B, C, D and F, is presented and compared with CO2-production data obtained under 301B conditions in the Sealed Vessel Test . For simple materials, the shape of the curves, not easily seen with CO2 production or DOC removal data, is clearly biphasic with a sigmoidal first part-suggesting growth of the inoculum on the test materials . For a selection of rapidly and readily biodegradable materials, the removal of soluble carbon was complete at the end of the first, sigmoidal part of the biodegradation curve; It is speculated that the remainder of the curve probably represents the mineralisation of part of the biomass . The respirometer generated many hundred data points per degradation curve and Monod or exponential growth models were fitted and growth parameters were derived . Growth rates under ready test conditions were derived for six materials as follows: aniline mu = 0.31 h-1, ethanolamine mu = 0.13 h-1, 1,6-hexanediol mu = 0.05 h-1, pentaerythritol mu = 0.04 h-1, C12.8EO mu = 0.13 h-1 and commercial LAS mu = 0.05 h-1. Spine, 1996 Sep 15, 21(18), 2123 - 9; discussion 2129-30 Biocompatible osteoconductive polymer versus iliac graft . A prospective comparative study for the evaluation of fusion pattern after anterior cervical discectomy; Madawi AA et al.; STUDY DESIGN: One hundred fifteen patients having symptomatic cervical disc disease were recruited prospectively for this study . They were allocated randomly for either autologous iliac bone graft or biocompatible osteoconductive polymer implants . Both groups were compared clinically and radiologically . OBJECTIVES: Complications, long-term clinical and radiologic outcome, and hospital stay were compared to determine if biocompatible osteoconductive polymer was an improvement on iliac bone graft in terms of reduced donor site pain and shortened hospital stay . SUMMARY OF BACKGROUND DATA: Donor site morbidity is a significant problem in anterior cervical fusion . Hospital stay is another factor in the recent era of cost consciousness . Biocompatible osteoconductive polymer has been used in many centers as a biodegradable implant to circumvent these problems . METHODS: Smith-Robinson technique was used in 74 patients, and Cloward technique was used in 41 patients . Sixty-five patients had biocompatible osteoconductive polymer implants, and 50 patients had iliac bone graft . Patients were followed-up routinely in the outpatient clinic where pain visual analogue scale and Odom's criteria were used for outcome evaluation . Plain radiography, computed tomography scan, and magnetic resonance imaging were used for radiologic evaluation . RESULTS: The mean hospital stay was 4.8 days for those with iliac bone graft and 4.7 days for those with biocompatible osteoconductive polymer . Clinical outcome was identical in both groups . The incidence of partial graft protrusion and postoperative intersegmental kyphosis was statistically higher with iliac bone graft (P = 0.018 and P = 0.02, respectively) . "Sclerosis" started to form around biocompatible osteoconductive polymer like a "halo" at 2 months . It increased with time, and sometimes was associated with new osteophyte formation; however, there was no biocompatible osteoconductive polymer incorporation or biodegradation CONCLUSIONS: Biocompatible osteoconductive polymer acts as a good "spacer" that reduces graft collapse and intersegmental kyphosis . However, it did not show any radiologic evidence of biodegradation or incorporation during the follow-up period of 24 months. Toxicol Ind Health, 1996 Sep-Oct, 12(5), 697 - 721 Treatment of organic water contaminants in oil refinery effluents investigated by using a simulation model; Siljeholm J; In this paper the wastewater treatment of organic compounds, particularly the water soluble (polar) compounds in refinery effluents, is simulated by addressing biodegradation, adsorption, and stripping/volatilization . The study examines pollutant data from two refineries in Norway and one in the United States . Previously, little attention has been paid to polar compounds . However, they are present in effluents, sometimes in large amounts, and are difficult to characterize and quantify . The study shows that many polar compounds, including the recently introduced methyl-tertiary-butyl-ether, are biodegraded by < 10% in simulated wastewater treatment . The concentrations of some polymers are barely reduced at all, and some metabolites of nonionic surfactants increase in toxicity along the route of degradation, resulting in an end product of the highest toxicity . The study demonstrates that of the substances entering the treatment systems, the residual of selected polar compounds is 38% of the incoming amount, while oil is reduced to 8% . It can be inferred from the study that polar compounds are contaminants, many of which may pose a pollution problem, and that reduction of polar compounds in effluents should be carried out upstream at the source of pollution, rather than downstream by end-of-pipe treatment. Gan To Kagaku Ryoho, 1996 Sep, 23(11), 1512 - 5 {Intraperitoneal administration of carboplatin loaded alpha-tricalcium phosphate (alpha-TCP) particles in rats bearing abdominal carcinomatosis}; Ueda T et al.; It is difficult to treat abdominal carcinomatosis with conventional chemotherapy, and many kinds of localized chemotherapy have been attempted . We used alpha-tricalcium phosphate (alpha-TCP) particles as a drug carrier in this study . alpha-TCP, which has chemically similar properties to human bone, has an excellent biocompatibility with human tissues and is biodegradable . The particles measured 50 to 100 microns in diameter, were round in shape and very porous . These particles have many open micro-pores of about 1 to 3 microns, which are beneficial for containing drugs . The compatibility and biodegradation of alpha-TCP particles were studied following intraperitoneal (ip) administration in normal rats . The following results were obtained: (1) alpha-TCP particles were intaken in the great omentum, and dissolved gradually . (2) The efficacy of ip administration of carboplatin-loaded alpha-TCP (alpha-TCP-CBDCA) was examined using a Donryu rat model with AH130 abdominal carcinomatosis . The alpha-TCP-CBDCA contained 200 mg alpha-TCP and 4 mg CBDCA . The pharmacokinetics of CBDCA following ip administration of alpha-TCP-CBDCA were studied . Pt levels in ascites and great omentum were higher in the alpha-TCP-CBDCA ip from 0.5 to 168 hours than those in the free-CBDCA ip and iv groups . These results suggest that the efficacy of CBDCA may be enhanced by utilizing alpha-TCP particles as a drug delivery carrier. Microbiol Rev, 1996 Sep, 60(3), 483 - 98 Microbial metabolism of pyridine, quinoline, acridine, and their derivatives under aerobic and anaerobic conditions; Kaiser JP et al.; Our review of the metabolic pathways of pyridines and aza-arenes showed that biodegradation of heterocyclic aromatic compounds occurs under both aerobic and anaerobic conditions . Depending upon the environmental conditions, different types of bacteria, fungi, and enzymes are involved in the degradation process of these compounds . Our review indicated that different organisms are using different pathways to biotransform a substrate . Our review also showed that the transformation rate of the pyridine derivatives is dependent on the substituents . For example, pyridine carboxylic acids have the highest transformation rate followed by mono-hydroxypyridines, methylpyridines, aminopyridines, and halogenated pyridines . Through the isolation of metabolites, it was possible to demonstrate the mineralization pathway of various heterocyclic aromatic compounds . By using 14C-labeled substrates, it was possible to show that ring fission of a specific heterocyclic compound occurs at a specific position of the ring . Furthermore, many researchers have been able to isolate and characterize the microorganisms or even the enzymes involved in the transformation of these compounds or their derivatives . In studies involving 18O labeling as well as the use of cofactors and coenzymes, it was possible to prove that specific enzymes (e.g., mono- or dioxygenases) are involved in a particular degradation step . By using H2 18O, it could be shown that in certain transformation reactions, the oxygen was derived from water and that therefore these reactions might also occur under anaerobic conditions. Invest Ophthalmol Vis Sci, 1996 Sep, 37(10), 1975 - 83 The involvement of polyamines in the proliferation of cultured retinal pigment epithelial cells; Yanagihara N et al.; PURPOSE: To investigate the involvement of polyamines (putrescine, spermidine, and spermine) in the proliferation of retinal pigment epithelium (RPE) using cultured bovine RPE cells . METHODS: The polyamine content and the activities of rate-limiting enzymes in polyamine biosynthesis (ornithine decarboxylase {ODC} and S-adenosylmethionine decarboxylase {SAMDC}) and in polyamine biodegradation (spermidine spermine N1-acetyltransferase {SAT}) were measured after proliferative stimulation by 10% fetal calf serum (FCS) . DNA synthesis was determined by {3H}thymidine incorporation into the acid-insoluble fraction after the addition of an inhibitor of ODC (alpha-difluoromethylornithine {DFMO}) or SAMDC (methylglyoxal bis{guanylhydrazone} {MGBG}) . The effects of exogenous polyamines on DNA synthesis after the additions of inhibitors also were determined . RESULTS: ODC and SAMDC activities were elevated after stimulation by FCS and reached their peaks 16 hours and 4 hours, respectively, after the addition of FCS . SAT activity was not increased . Polyamine content was increased significantly after stimulation by FCS . DFMO did not inhibit DNA synthesis induced by FCS, and only putrescine content was decreased significantly among polyamines . However, MGBG inhibited DNA synthesis in a dose-dependent manner, and the amounts of spermidine and spermine were decreased significantly . Exogenous polyamines, especially spermine, restored MGBG-induced inhibition of DNA synthesis . CONCLUSIONS: Polyamines are essential for the proliferation of cultured bovine RPE cells . These data suggest that, of the polyamines, spermine has the greatest effect on DNA synthesis although other polyamines can substitute for spermine at higher concentrations with similar results . As for polyamine metabolism in RPE proliferation, it is possible that SAMDC is the key enzyme rather than ODC. Appl Environ Microbiol, 1996 Sep, 62(9), 3371 - 7 Biodegradation of individual and multiple chlorinated aliphatic hydrocarbons by methane-oxidizing cultures; Chang HL et al.; The microbial degradation of chlorinated and nonchlorinated methanes, ethanes, and ethanes by a mixed methane-oxidizing culture grown under chemostat and batch conditions is evaluated and compared with that by two pure methanotrophic strains: CAC1 (isolated from the mixed culture) and Methylosinus trichosporium OB3b . With the exception of 1,1-dichloroethylene, the transformation capacity (Tc) for each chlorinated aliphatic hydrocarbon was generally found to be in inverse proportion to its chlorine content within each aliphatic group (i.e., methanes, ethanes, and ethenes), whereas similar trends were not observed for degradation rate constants . Tc trends were similar for all methane-oxidizing cultures tested . None of the cultures were able to degrade the fully chlorinated aliphatics such as perchloroethylene and carbon tetrachloride . Of the four cultures tested, the chemostat-grown mixed culture exhibited the highest Tc for trichloroethylene, cis-1,2-dichloroethylene, tetrachloroethane, 1,1,1-trichloroethane, and 1,2-dichloroethane, whereas the pure batch-grown OB3b culture exhibited the highest Tc for all other compounds tested . The product toxicity of chlorinated aliphatic hydrocarbons in a mixture containing multiple compounds was cumulative and predictable when using parameters measured from the degradation of individual compounds . The Tc for each chlorinated aliphatic hydrocarbon in a mixture (Tcmix) and the total Tc for the mixture (sigma Tcmix) are functions of the individual Tc, the initial substrate concentration (S0), and the first-order rate constant (k/Ks) of each compound in the mixture, indicating the importance of identifying the properties and compositions of all potentially degradable compounds in a contaminant mixture. Chemosphere, 1996 Sep, 33(6), 1195 - 210 Carbon dioxide recovery in ready biodegradation tests: mass transfer and kinetic considerations; Larson RJ et al.; The kinetics and efficiency of carbon dioxide recovery in modern versions of the Sturm Ready Biodegradation Test were examined to determine the ability of CO2 evolution measurements to accurately estimate the rate and extent of ultimate biodegradation (mineralization) . Kinetic data were analyzed by nonlinear regression techniques using an automated curve-fitting package available from commercial sources . The kinetics of CO2 recovery in standard 3.8 L glass carboys containing 2 L of medium were rapid when headspace aeration (approximately 6 ml/min) and moderate agitation (140 rev/min) on a rotary platform shaker were used to ensure adequate aeration and mixing . The time (half-life) for 50% CO2 recovery in external base traps was 4-5 hours, and stoichiometric recoveries of CO2 equivalents added as bicarbonate were obtained within 24 hours . The kinetics of CO2 evolution during biodegradation of several test compounds were significantly slower than the kinetics of CO2 recovery, with half-lives between 65 and 191 hours . Our results indicate that mass transfer limitations do not impact CO2 recoveries or biodegradation kinetic measurements in modern versions of the Sturm Test, even in test vessels with relatively low surface area to volume ratios (1:1) . The use of headspace aeration and mixing generates reliable kinetic data, which can be analyzed by commercially-available nonlinear regression packages to provide rate information for the classification of chemicals with different biodegradation profiles. Chemosphere, 1996 Sep, 33(5), 817 - 30 An energy budget model for the biodegradation and cometabolism of organic substances; Cornelissen G et al.; Expression of bacterial cellular processes (maintenance, heat loss, growth, cometabolism and substrate degradation) into energy units yielded surprisingly realistic figures on the bacterial energy balance in spite of the severe approximations and assumptions that had to be made . For studies without cometabolism, 47-83% of the calculated amount of available energy was consumed by growth; for maintenance + heat loss this percentage was 20-35% . When involved, cometabolism consumed 7-13% of the total energy budget . Overall, 67-118% of the calculated amount of energy generated was spent on these energy-consuming processes . This shows that the model is internally consistent . Relationships between growth and cometabolism may offer predictions of persistence of cometabolizable chemicals under different conditions . The energy budget model as presented provides a starting point for the development of such relationships . In addition, the method is used to explain threshold concentrations, below which normally degradable compounds are not degraded. Biodegradation, 1996 Aug, 7(4), 329 - 33 Biodegradation of rubber particles in soil; Keursten GT et al.; The biodegradation of rubber particles in rubber-soil mixtures at different rubber contents was monitored by the carbon dioxide production . The cumulative carbon dioxide production was modelled according to a two parameter exponential function . The model provides an excellent fit (R2 > 0.98) for the observed data . The two parameters yield a reliable estimate of the half-life for the process observed, but estimation of the true half-life of rubber in soil will need more research. J Biomed Mater Res, 1996 Aug, 31(4), 439 - 44 Preparation of stable aqueous solution of keratins, and physiochemical and biodegradational properties of films; Yamauchi K et al.; A stable aqueous solution of reduced keratins was prepared by extracting the proteins from wool (Corriedale) with a mixture of urea, mercaptanol, surfactant, and water at 40-60 degrees C . Sodium dodecyl sulfate was especially effective as a surfactant, not only in promoting extraction but also in stabilizing the aqueous protein solution . The proteins had the following constants: MW, 52,000-69,000 daltons; cysteine content, 8-9 mol%; pl about 6.7 . A clear film was readily prepared from a keratin solution containing glycerol . The film was insoluble in water and organic solvents including dimethyl sulfoxide . The keratin film was permeable to glucose, urea, and sodium chloride . The keratin film was degraded in vitro (by trypsin) and in vivo (by subcutaneous embedding in mice). Appl Environ Microbiol, 1996 Aug, 62(8), 2910 - 4 Aerobic biodegradation of 4-methylquinoline by a soil bacterium; Sutton SD et al.; Methylquinolines and related N-heterocyclic aromatic compounds are common contaminants associated with the use of hydrocarbons in both coal gasification and wood treatment processes . These compounds have been found in groundwater, and many are known mutagens . A stable, five-member bacterial consortium able to degrade 4-methylquinoline was established by selective enrichment using soil collected from an abandoned coal gasification site . The consortium was maintained for 5 years by serial transfer in a medium containing 4-methylquinoline . A gram-negative soil bacterium, strain Lep1, was isolated from the consortium and shown to utilize 4-methylquinoline as a source of carbon and energy during growth in liquid medium . A time course experiment demonstrated that both the isolate Lep1 and the consortium containing Lep1 were able to degrade 4-methylquinoline under aerobic conditions . Complete degradation of 4-methylquinoline by either strain Lep1 alone or the consortium was characterized by the production and eventual disappearance of 2-hydroxy-4-methylquinoline, followed by the appearance and persistence of a second metabolite tentatively identified as a hydroxy-4-methylcoumarin . Currently, there is no indication that 4-methylquinoline degradation proceeds differently in the consortium culture compared with Lep1 alone . This is the first report of 4-methylquinoline biodegradation under aerobic conditions. Proc Natl Acad Sci U S A, 1996 Jul 23, 93(15), 7917 - 22 Correction in trans for Fabry disease: expression, secretion and uptake of alpha-galactosidase A in patient-derived cells driven by a high-titer recombinant retroviral vector; Medin JA et al.; Fabry disease is an X-linked metabolic disorder due to a deficiency of alpha-galactosidase A (alpha-gal A; EC 3.2.1.22) . Patients accumulate glycosphingolipids with terminal alpha-galactosyl residues that come from intracellular synthesis, circulating metabolites, or from the biodegradation Of senescent cells . Patients eventually succumb to renal, cardio-, or cerebrovascular disease . No specific therapy exists . One possible approach to ameliorating this disorder is to target corrective gene transfer therapy to circulating hematopoietic cells . Toward this end, an amphotropic virus-producer cell line has been developed that produces a high titer (>10(6) i.p . per ml) recombinant retrovirus constructed to transduce and correct target cells . Virus-producer cells also demonstrate expression of large amounts of both intracellular and secreted alpha-gal A . To examine the utility of this therapeutic vector, skin fibroblasts from Fabry patients were corrected for the metabolic defect by infection with this recombinant virus and secreted enzyme was observed . Furthermore, the secreted enzyme was found to be taken up by uncorrected cells in a mannose-6-phosphate receptor-dependent manner . In related experiments, immortalized B cell lines from Fabry patients, created as a hematologic delivery test system, were transduced . As with the fibroblasts, transduced patient B cell lines demonstrated both endogenous enzyme correction and a small amount of secretion together with uptake by uncorrected cells . These studies demonstrate that endogenous metabolic correction in transduced cells, combined with secretion, may provide a continuous source of corrective material in trans to unmodified patient bystander cells (metabolic cooperativity). Appl Microbiol Biotechnol, 1996 Jul, 45(6), 831 - 8 Aerobic biodegradation of selected monoterpenes; Misra G et al.; Batch experiments were conducted to assess the biotransformation potential of four hydrocarbon monoterpenes (d-limonene, alpha-pinene, gamma-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and alpha-terpineol) under aerobic conditions at 23 degrees C . Both forest-soil extract and enriched cultures were used as inocula for the biodegradation experiments conducted first without, then with prior microbial acclimation to the monoterpenes tested . All four hydrocarbons and two alcohols were readily degraded . The increase in biomass and headspace CO2 concentrations paralleled the depletion of monoterpenes, thus confirming that terpene disappearance was the result of biodegradation accompanied by microbial growth and mineralization . Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly . A significant fraction of d-limonene-derived carbon was accounted for as non-extractable, dissolved organic carbon, whereas terpineol exhibited a much higher degree of utilization . The rate and extent of monoterpene biodegradation were not significantly affected by the presence of dissolved natural organic matter. J Biomater Appl, 1996 Jul, 11(1), 37 - 61 Small caliber vascular grafts . Part II: Polyurethanes revisited; Zdrahala RJ; Polyurethanes are considered to be one of the most bio- and blood-compatible biomaterials known today . By intelligent utilization of principles governing the structure/property relationship of these polymers, one can generate systems which resemble, in principle, the physical-mechanical behavior of living tissue . Thus, it is not surprising that these materials played a major role in development of small caliber vascular grafts targeted for vascular access, peripheral and coronary artery bypass indications . Numerous technologies, often esoteric in nature, were and are utilized to generate porous, potentially multilayered conduits possessing some or many characteristics of natural blood vessels . Properties such as durability, elasticity, compliance, pulsatility, and propensity for healing became attainable via polyurethanes . Furthermore, additional surface and/or bulk modification via attachments of biologically active species such as anticoagulants, cell proliferation suppressants, anti-infective compounds or biorecognizable groups are possible due to reactive groups which are part of the polyurethane structure . These modifications are designed to control or mediate host acceptance and healing of the graft . Finally, a myriad of practical processing technologies are used to fabricate functional grafts . Among those, casting, electrostatic and wet spinning of fibers and monofilaments, extrusion, dip coating or spraying of mandrels with polymer/additive solutions are often coupled with chemical-potential-difference-driven coagulation and phase inversion leading to grafts feeling and often behaving like natural vessels . Historically, the first polyurethanes utilized were hydrolytically unstable polyester polyurethanes containing hydrolysis-prone polyester polyols as soft segments, followed by hydrolytically stable but oxidation sensitive polyether polyols based polyurethanes . Polyether-based polyurethanes and their clones containing silicone and other modifying polymeric intermediates represented significant progress . Many viable technologies were discovered and developed using polyether-based polyurethanes . Chronic in vivo instability observed on prolonged implantation became, however, a major roadblock . The path led finally to the use of hydrolytically and oxidatively stable polycarbonate polyols as the soft segment to generate biodurable materials with resistance to biodegradation adequate for vascular access or perhaps peripheral graft indications . This biodurability needs to be further increased in order to utilize the full potential of polyurethanes in development of patent small caliber graft . Modification of both the soft and hard segments needs to be considered in order to maximize biodurability of both basic building blocks of the polyurethane . This paper reviews the achievements, discusses trends, and offers the view of the future in this exciting area of material/device combination. Cleft Palate Craniofac J, 1996 Jul, 33(4), 277 - 83 Biologic responses of autogenous bone and beta-tricalcium phosphate ceramics transplanted into bone defects to orthodontic forces; Hossain MZ et al.; This study was conducted to evaluate biologic responses of autogenous bone (particulate marrow and cancellous bone; PMCB) and beta-tricalcium phosphate ceramics (TCPC) to orthodontic stimuli . Nine dogs served as the experimental animals; three dogs underwent orthodontic tooth movement after grafting, three dogs received PMCB grafting without tooth movement, and three dogs received TCPC grafting without tooth movement . Immediately after extraction of the upper second and/or third incisors, the maxillary alveolar bone was resected bilaterally . Autogenous PMCB obtained from the iliac bone and TCPC were transplanted into each bone defect . Experimental tooth movement was initiated 2 to 4 weeks after the grafting and continued for 9 to 15 weeks . Sectional archwires with open-coll springs were used for distal movement of the upper first incisors into the extraction sites . Oxytetracycline and calcein were employed as bone markers . Sections of grafted areas including the teeth were prepared for light and fluorescence microscopy . The results revealed that both autogenous bone and TCPC presented similar adaptive changes to the original alveolar bone without any external stimuli . TCPC exhibited more prominent biodegradative responses to orthodontic force in association with new cementum formation . Root resorption was also less in the TCPC area than in the PMCB region . It is shown that TCPC is biodegradative in nature and adaptive for remodeling during orthodontic tooth movement . This finding indicates that TCPC may be a better biocompatible alternative to autogenous bone transplanted into bone defects subjected to orthodontic tooth movement. Appl Environ Microbiol, 1996 Jul, 62(7), 2411 - 5 Metabolic efficiency and turnover of soil microbial communities in biodegradation tests; Shen J et al.; Biodegradability screening tests of soil commonly measure 14CO2 evolution from radiolabeled test compounds, and glucose has often served as a positive control . When constant amounts of radiolabel were added to soil in combination with increasing amounts of unlabeled substrates, glucose and some related hexoses behaved in an anomalous manner . In contrast to that of formate, benzoate, n-hexadecane, or bis(2-ethylhexyl) phthalate, dilution of glucose radiocarbon with unlabeled glucose increased rather than decreased the rate and extent of 14CO2 evolution . {14C}glucose incorporation into biomass and Vmax values were consistent with the interpretation that application of relatively high concentrations of glucose to soil shifts the balance of the soil microbial community from the autochthonous (humus-degrading) to the zymogeneous (opportunistic) segment . The higher growth and turnover rates that define zymogeneous microorganisms, combined with a lower level of carbon incorporation into their biomass, result in the evolution of disproportionate percentages of 14CO2 . When used as positive controls, glucose and related hexoses may raise the expectations for percent 14CO2 evolution to levels that are not realistic for other biodegradable compounds. Appl Environ Microbiol, 1996 Jul, 62(7), 2393 - 7 Screening of microorganisms for biodegradation of poly(lactic-acid) and lactic acid-containing polymers; Torres A et al.; The ability of some microorganisms to use lactic acid stereocopolymers and copolymers with glycolic acid as sole carbon and energy sources was studied under controlled or natural conditions . First, 14 filamentous fungal strains were tested in liquid cultures, adopting total lactic acid consumption, nitrogen source exhaustion, and maximal biomass production as selection criteria . Two strains of Fusarium moniliforme and one strain of Penicillium roqueforti were able to totally assimilate DL-lactic acid, partially soluble racemic oligomers (MW = 1,000), and the nitrogen source . Only one strain of F . moniliforme was able to grow on a poly(lactic acid)-glycolic acid copolymer (MW = 150,000) after 2 months of incubation at 28 degrees C on synthetic agar medium . Mycelium development was examined by scanning electron microscopy . F . moniliforme filaments were observed to grow not only at the copolymer surface but also through the bulk of the copolymer . In a second approach, plates made of a racemic poly(lactic acid) were buried in the soil before being incubated in petri dishes containing mineral agar medium under controlled conditions . Five strains of different filamentous fungi were isolated, and their ability to assimilate racemic poly(lactic acid) oligomers was tested in liquid cultures. Chemosphere, 1996 Jul, 33(2), 203 - 15 Effects of ryegrass on biodegradation of hydrocarbons in soil; Gunther T et al.; The effects of growing ryegrass (Lolium perenne L.) on the biodegradation of hydrocarbons was studied in laboratory scale soil columns . Degradation of hydrocarbons as well as bacterial numbers, soil respiration rates and soil dehydrogenase activities were determined . In the rhizosphere soil system, aliphatic hydrocarbons disappeared faster than in unvegetated columns . Abiotic loss by evaporation was of minor significance . Elimination of pollutants was accompanied by an increase in microbial numbers and activities . The microbial plate counts and soil respiration rates were substantially higher in the rhizosphere than in the bulk soil . The results indicate that biodegradation of hydrocarbons in the rhizosphere is stimulated by plant roots. Arch Environ Contam Toxicol, 1996 Jul, 31(1), 98 - 106 Effects of fertilizer on insecticides adsorption and biodegradation in crop soils; Rouchaud J et al.; Recent organic fertilizer treatments (cow manure, pig slurry, composts, or green manure) simultaneously increase insecticide adsorption onto soil and the insecticide soil persistence, indicating a mechanism of slow release of insecticide into soil by the organic matter . This occurred in sugar beet crops with aldicarb, thiofanox and imidacloprid; also, in leek, cauliflower and brussels sprouts crops with chlorpyrifos and chlorfenvinphos . In contrast, organic fertilizer treatments applied once or repeatedly in the past, have no significant influence on adsorption or persistence of insecticides; the same is observed for the old soil organic matter, when its soil concentrations change in limited ranges Chemosphere, 1996 Jul, 33(1), 107 - 30 Factors affecting the biodegradation of toluene in soil; Davis JW et al.; The biodegradation of toluene in soil microcosms was examined in order to identify the physical, chemical, and biological factors which determine the fate and lifetime of organic chemicals in soils . Toluene degradation rates were proportional to the initial substrate concentration and these rates reached a maximum at a concentration of 200 micrograms/g . No degradation occurred above this concentration presumably due to the toxicity of the hydrocarbon to the soil microorganisms . Small differences were observed in the degradation rates in soils at different moisture content . However, the availability of water in soil appeared to limit toluene degradation only at a very low water content . The lifetime of toluene in soil was also related to the initial level and activity of the soil microorganisms . Toluene was metabolized rapidly in those soils which initially contained high levels of degrading microorganisms . Furthermore, exposure of the soil to toluene resulted in an increase in the number of degrading organisms . The lack of inorganic nutrients such as nitrogen prevented complete degradation of toluene in a clay soil which contained high levels of degrading microorganisms . The biodegradation of organic chemicals in soil is not an intrinsic property of the molecule and cannot be predicted without first delineating the environment in which it is found . The biodegradation of a compound is defined by the biological, physical, and chemical characteristics of the soil environment . The lifetime of a chemical in soil results from a combination of all three of these parameters. Forensic Sci Int, 1996 Jun 14, 79(3), 167 - 74 A high fatal postmortem blood concentration of cocaine in a drug courier; Patel F; A fatality in a teenage drug courier who swallowed multiple packages of a controlled drug for concealment in the gastrointestinal tract is described . There were a couple of burst-open short cylindrical packages of cocaine and several with damaged external latex wrapping . A hazardous breakage or leakage has been considered unlikely with similar type of cocaine packages otherwise . The deceased succumbed to a remarkably high fatal postmortem blood cocaine concentration of 104 mg/l, having curiously survived the usual lethal range for cocaine toxicity . The phenomenon of postmortem release and redistribution of drugs and spontaneous biodegradation of cocaine which may confound the postmortem toxicology is briefly discussed . There is a comparable forensic problem in estimating the time of drug ingestion from the rate of gastric emptying or transit in the gut as a crude guide to deduce the time of death. Curr Opin Biotechnol, 1996 Jun, 7(3), 295 - 300 Biodegradation of chlorinated aliphatic compounds; Leisinger T; During the past year, the range of environmentally relevant chlorinated aliphatic compounds known to serve as growth substrates for pure cultures of bacteria has been extended and novel reactions for the aerobic co-metabolic transformation of chloroaliphatics have been reported . The biochemistry of chloroaliphatics degradation in the new aerobic isolates is still unexplored, but progress has been made in understanding some of the anaerobic dehalogenation reactions. Biodegradation, 1996 Jun, 7(3), 183 - 9 The anaerobic biodegradation of diethanolamine by a nitrate reducing bacterium; Knapp JS et al.; The ability of bacterial cultures to degrade diethanolamine under anoxic conditions with nitrate as an electron acceptor was investigated . A mixed culture capable of anaerobic degradation of diethanolamine was obtained from river sediments by enrichment culture . From this a single bacterial strain was isolated which could use diethanolamine, monoethanolamine, triethanolamine and N-methyl diethanolamine as its sole carbon and energy sources either aerobically or anaerobically . Growth on diethanolamine was faster in the absence of oxygen . The accumulation of possible metabolites in the culture medium was determined as was the ability to grow on certain putative intermediates in the degradation of diethanolamine . A possible pathway for the degradation of ethanolamines by this organism is suggested. Fukuoka Igaku Zasshi, 1996 Jun, 87(6), 142 - 50 {Biodegradation of herbicide chlornitrofen (CNP) and mutagenicity of its degradation products}; Kitamori S; Mutagenicities of three diphenyl ether-derived herbicides, chlornitrofen (CNP), nitrofen and chlormethoxynil, and their amino derivatives were assayed by the Ames test using TA98, TA100 and YG strains, recently developed tester strains . As for CNP, mutagenicities of its biodegradation products were also assayed, and biodegradation of CNP and change in mutagenic potency were examined using river water to which CNP was added . CNP was weakly mutagenic in YG1029, and nitrofen was weakly mutagenic in YG1029, while highly mutagenic in YG1026 . But neither of three herbicides were mutagenic using TA98 and TA100 . All of their amino derivatives were mutagenic especially in YG1024 and YG1029, acetyltransferase-rich mutants of TA98 or TA100 . In YG1029, mutagenic potency of the amino derivatives was relatively high compared with that of each parent compound . Concerning biodegradation products of CNP, amino-CNP was highly mutagenic and acethylamino-CNP was moderately mutagenic in YG 1026, but others were non-mutagenic . In river water, CNP was degraded rapidly and converted to amino-CNP . Change in mutagenicity of river water to which CNP was added seemed to reflect changes in amino-CNP concentration in river water . Therefore, assessing health impact of chemicals released in natural environment, their degradation products must be considered along with parent compounds. Am J Cardiol, 1996 May 30, 77(13), 38C - 40C Organic nitrates: new formulations and their clinical advantages; Parker JA; The organic nitrates have been used for more than a century in the management of patients with myocardial ischemia . The most commonly used agents at this time include nitroglycerin, isosorbide dinitrate, and isosorbide-5-mononitrate . These agents all exert their therapeutic effects through biodegradation to nitric oxide, which stimulates guanylate cyclase in vascular smooth muscle cells with the production of cyclic guanosine monophosphate . The latter induces vasodilation by reducing the availability of ionized calcium to the contractile proteins . Tolerance to the organic nitrates occurs when the agents are administered in an attempt to provide therapeutic effects throughout 24 hours each day . There are probably several mechanisms responsible for nitrate tolerance, but there is no evidence at this time that concurrent medications will modify the development of tolerance . The only available method at this time is to give these agents intermittently to provide a period of washout . In so doing, it is possible to provide therapeutic nitrate effects for approximately 12 hours throughout each 24-hour period. Ophthalmic Surg Lasers, 1996 May, 27(5), 384 - 91 In vitro evaluation of polymeric matrix and porous biodegradable reservoir devices for slow-release drug delivery; Peyman GA et al.; BACKGROUND AND OBJECTIVE: Biodegradable polymeric devices were evaluated in vitro for intravitreal drug delivery . MATERIALS AND METHODS: The matrix (short-term drug delivery) and the porous (longer-term drug delivery) reservoir devices were made from polycaprolactone of two molecular weights (30,000 and 56,000) . Matrix devices were loaded with 5-fluorouracil or ganciclovir . Porous reservoirs were loaded with 5-fluorouracil, ganciclovir, 5-carboxyfluorescein, or foscarnet . The release was monitored in phosphate-buffered solution using ultraviolet spectrophotometry . RESULTS: Release from the matrix devices was characterized by an initial burst, followed by a nonlinear release . The porous reservoirs demonstrated zero order linear release of drugs, sustained up to 250 days in this experiment . CONCLUSIONS: The matrix device is capable of sustained release over several months; the porous reservoir can deliver drugs for over 1 year . Further studies are needed to evaluate in vivo biodegradation behavior and toxicity of drugs used for sustained release. Biomaterials, 1996 May, 17(9), 873 - 8 Unacceptable biodegradation of polyethylene in vivo; Brach del Prever E et al.; The chemical characterization of 19 retrieved ultra-high-molecular-weight polyethylene tibial plateaux, six new ones and one raw bar was performed by means of infrared spectroscopy . The surface and bulk oxidation and biodegradation indexes were calculated . The raw bar has a measurable oxidation, which increases on the bulk and on the surfaces of the new plateaux . In the retrieved plateaux, the average oxidation index increases further both on the bulk and on the surfaces; the worse values were present on the worn area . Similar results were found for the biodegradation index . The data show that the biotic in vivo degradation is promoted by the oxidation present on the new plateaux and that it occurs through a different mechanism, abiotic thermal-, photo-, gamma-radiation oxidation, evaluated by the oxidation index. Microbiology, 1996 May, 142 ( Pt 5), 1311 - 20 Molecular characterization of adiY, a regulatory gene which affects expression of the biodegradative acid-induced arginine decarboxylase gene (adiA) of Escherichia coli; Stim-Herndon KP et al.; A transcriptional regulator gene, designated adiY, was found downstream of the biodegradative arginine decarboxylase (adiA) gene (previously known as adi) of Escherichia coli . The arginine decarboxylase system is maximally induced under conditions of acidic pH, anaerobiosis and rich medium, and AdiY was found to increase the expression of adiA . The DNA sequence of adiY encodes a protein of 253 amino acids . Primer extension analysis defined the promoter . The amino acid sequence of AdiY showed homology to the XylS/AraC family of transcriptional regulators, which includes EnvY and AppY . Studies suggested that sequences required for acid induction were also necessary to observe the stimulation by AdiY . An examination of the substitution of AdiY, AppY and EnvY showed that these three proteins can, to some extent, stimulate the other systems. Microbiology, 1996 May, 142 ( Pt 5), 1123 - 31 Ether-bond scission in the biodegradation of alcohol ethoxylate nonionic surfactants by Pseudomonas sp . strain SC25A; Tidswell EC et al.; Pseudomonas sp . strain SC25A, previously isolated for its ability to grow on alcohol ethoxylates (PEG dodecyl ethers) as sole source of carbon and energy, was shown to be capable of growth on the dodecyl ethers of mono-, di, tri- and octaethylene glycols . Comparative growth yields for this series of alcohol ethoxylate nonionic surfactants indicated that, whereas all of the carbon of monoethylene glycol dodecyl ether (MEGDE) was assimilable, only the alkyl chains were assimilated from the higher ethoxamers . These results are interpreted in terms of a primary biodegradation mechanism in which the scission of the dodecyl-ether bond is the first step . In the case of MEGDE this step separates the dodecyl chain from a C2 fragment, both of which are readily assimilable; for the higher ethoxamers, the assimilable dodecyl chain is accompanied by an ether-containing PEG derivative which would require further rounds of either scission before assimilation . Whole cells and cell extracts converted {1-14C}MEGDE initially and very rapidly to radiolabelled dodecanol . Disappearance of {14C}dodecaol was accompanied by production of {14C}dodecanal . {14C}Dodecanoic acid was present at relatively low concentrations throughout the incubation periods . {14C}Dodecan-1, 12-dioic acid was produced in significant quantities (up to 25% radiolabel), and the onset of its production coincided with the peak concentration of dodecanal, the disappearance of which mirrored the appearance of the dioic acid . Under anaerobic conditions in the presence of cell extracts, dodecanol (55% of radiolabel) and dodecanal (22%) accumulated rapidly from MEGDE, but there was little subsequent conversion to mono- or dicarboxylic acids . These results are interpreted in terms of a pathway initiated by dodecyl-ether cleavage to produce dodecanol, which is subsequently oxidized to dodecanal and dodecanoic acid . The formation of dodecan-1, 12-dioic acid, probably from dodecanal, may represent a means of harbouring carbon under non-growing conditions. Biochem Biophys Res Commun, 1996 Apr 25, 221(3), 755 - 61 Novel polypeptides induced by the insecticide lindane (gamma-hexachlorocyclohexane) are required for its biodegradation by a Sphingomonas paucimobilis strain; Adhya TK et al.; When exposed to the potent insecticide gamma-hexachlorocyclohexane or lindane, a Sphingomonas paucimobilis strain rapidly synthesized 7 novel polypeptides and concomitantly gained the ability to degrade lindane . Synthesis of these proteins was switched-off subsequent to the disappearance of lindane from the medium . Treatments which induced the synthesis of identical proteins also conferred on cells the ability to degrade lindane . In contrast, cells blocked in protein synthesis could not be induced to degrade lindane . The close correspondence observed between expression of lindane-induced proteins and gamma-hexachlorocyclohexane catabolism strongly implicates these novel proteins in lindane biodegradation. FEMS Microbiol Lett, 1996 Apr 15, 138(1), 17 - 22 Rapid, direct extraction of DNA from soils for PCR analysis using polyvinylpolypyrrolidone spin columns; Berthelet M et al.; Polyvinylpolypyrrolidone spin columns were used to rapidly purify crude soil DNA extracts from humic materials for polymerase chain reaction (PCR) analysis . The PCR detection limit for the tfdC gene, encoding chlorocatechol dioxygenase from the 2,4-dichlorophenoxyacetic acid degradation pathway, was 10(1)-10(2) cells/g soil in inoculated soils . The procedure could be applied to the amplification of biodegradative genes from indigenous microbial populations from a wide variety of soil types, and the entire analysis could be performed within 8 h. Appl Environ Microbiol, 1996 Apr, 62(4), 1428 - 30 Priming effect of substrate addition in soil-based biodegradation tests; Shen J et al.; To test whether substrate addition changes background CO2 evolution of soil, we measured both 14CO2 and net CO2 evolution from various test compounds . Glucose caused a priming effect, defined as substrate-stimulated soil organic matter mineralization . Formate, benzoate, n-hexadecane, and bis(2-ethylhexyl)phthalate caused no priming, and phenol caused only a transient one . The priming effect of glucose appears to be unusual and does not require a general rejection of net CO2 evolution measurements in biodegradability testing. Appl Environ Microbiol, 1996 Apr, 62(4), 1159 - 66 Pristine soils mineralize 3-chlorobenzoate and 2,4-dichlorophenoxyacetate via different microbial populations; Fulthorpe RR et al.; Biodegradation of two chlorinated aromatic compounds was found to be a common capability of the microorganisms found in the soils of undisturbed, pristine ecosystems . We used 2,4-dichlorophenoxyacetate (2,4-D) and 3-chlorobenzoate (3CBA) as enrichment substrates to compare populations of degrading bacteria from six different regions making up two ecosystems . We collected soil samples from four Mediterranean (California, central Chile, the Cape region of South Africa, and southwestern Australia) and two boreal (northern Saskatchewan and northwestern Russia) ecosystems that had no direct exposure to pesticides or to human disturbance . Between 96 and 120 samples from each of the six regions were incubated with 50 ppm of {U-14C}2,4-D or {U-14C}3CBA . Soils from all regions samples mineralized both 2,4-D and 3CBA, but 3CBA was mineralized without a lag period, while 2,4-D was generally not mineralized until the second week . 3CBA degradative capabilities were more evenly distributed spatially than those for 2,4-D . The degradative capabilities of the soils were readily transferred to fresh liquid medium . 3CBA degraders were easily isolated from most soils . We recovered 610 strains that could release carbon dioxide from ring-labeled 3CBA . Of these, 144 strains released chloride and degraded over 80% of 1 mM 3CBA in 3 weeks or less . In contrast, only five 2,4-D degraders could be isolated, although a variety of methods were used in an attempt to culture the degraders . The differences in the distribution and culturability of the bacteria responsible for 3CBA and 2,4-D degradation in these ecosystems suggest that the two substrates are degraded by different populations . We also describe a 14C-based microtiter plate method that allows efficient screening of a large number of samples for biodegradation activity. Biodegradation, 1996 Apr, 7(2), 137 - 49 Biodegradation of atrazine in surface soils and subsurface sediments collected from an agricultural research farm; Radosevich M et al.; The purpose of the present study was to assess atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) mineralization by indigenous microbial communities and to investigate constraints associated with atrazine biodegradation in environmental samples collected from surface soil and subsurface zones at an agricultural site in Ohio . Atrazine mineralization in soil and sediment samples was monitored as 14CO2 evolution in biometers which were amended with 14C-labeled atrazine . Variables of interest were the position of the label ({U-14C-ring}-atrazine and {2-14C-ethyl}-atrazine), incubation temperature (25 degrees C and 10 degrees C), inoculation with a previously characterized atrazine-mineralizing bacterial isolate (M91-3), and the effect of sterilization prior to inoculation . In uninoculated biometers, mineralization rate constants declined with increasing sample depth . First-order mineralization rate constants were somewhat lower for {2-14C-ethyl}-atrazine when compared to those of {U-14C-ring}-atrazine . Moreover, the total amount of 14CO2 released was less with {2-14C-ethyl}-atrazine . Mineralization at 10 degrees C was slow and linear . In inoculated biometers, less 14CO2 was released in {2-14C-ethyl}-atrazine experiments as compared with {U-14C-ring}-atrazine probably as a result of assimilatory incorporation of 14C into biomass . The mineralization rate constants (k) and overall extents of mineralization (Pmax) were higher in biometers that were not sterilized prior to inoculation, suggesting that the native microbial populations in the sediments were contributing to the overall release of 14CO2 from {U-14C-ring}-atrazine and {2-14C-ethyl}-atrazine . A positive correlation between k and aqueous phase atrazine concentrations (Ceq) in the biometers was observed at 25 degrees C, suggesting that sorption of atrazine influenced mineralization rates . The sorption effect on atrazine mineralization was greatly diminished at 10 degrees C . It was concluded that sorption can limit biodegradation rates of weakly-sorbing solutes at high solid-to-solution ratios and at ambient surface temperatures if an active degrading population is present . Under vadose zone and subsurface aquifer conditions, however, low temperatures and the lack of degrading organisms are likely to be primary factors limiting the biodegradation of atrazine. Biodegradation, 1996 Apr, 7(2), 109 - 20 A dynamic river model for biodegradability studies: investigations with selected aromatic compounds at low concentrations and comparison with aquatic batch tests; Koziollek P et al.; The objective of this publication is to present a new dynamic aerobic biodegradation test method simulating a river . A laboratory cascade test system and standardized batch shake flask tests were used for biodegradation studies with the non-volatile and non-sorbing model compounds 2,4-dinitrophenol, naphthalene-1-sulphonic acid and sulphanilic acid . To be closer to the often very low concentrations of substances in the environment the concentrations of the compounds used were standard test concentrations and lower . 14C labelled compounds were measured at 50 micrograms/l, capillary electrophoresis at 5000 micrograms/l and the removal of dissolved organic carbon at 50000 micrograms/l . The test results obtained confirmed the known ultimate biodegradability of the test compounds and showed that biodegradation degrees, rates and degradation durations depended on the test systems, the concentrations of test compounds and the inocula . The river model is a suitable simulation test for natural dynamic surface waters which can be used to perform biodegradability studies at low test concentrations if adequate analytical tools, preferably radioactive-labelled substances, are available. J Biomed Mater Res, 1996 Apr, 30(4), 515 - 22 Composite biomaterials based on ceramic polymers . I . Reinforced systems based on Al2O3/PMMA/PLLA; Rodriguez-Lorenzo LM et al.; Composite biomaterials with good mechanical response and a partially biodegradable character were prepared by the free radical polymerization of mixtures of alpha-Al2O3, low-molecular-weight but crystalline poly(L-lactic acid) (PLLA), and methyl methacrylate (MMA) . Cylindrical specimens prepared with different composition were characterized by thermogravimetry, calorimetry, 1H-NMR spectroscopy, and x-ray diffraction (XRD) . The in vitro biodegradative process was studied in different media, following variations of the pH, gravimetric weight loss of the specimens, and crystalline domain change by XRD after immersion in pure water and buffered solutions at pH 4.0 and pH 8.0 for 90 days . Formation of a relatively porous structure with good cohesion after the biodegradative treatment (confirmed by SEM) was observed . These systems can be considered for applications in orthopedic surgery as filling biomaterials and even as control drug-delivery systems. J Biomed Mater Res, 1996 Apr, 30(4), 441 - 8 Crosslinked poly(1-vinyl-2-pyrrolidinone) as a vitreous substitute; Hong Y et al.; A hydrogel with a high water content was produced and tested as a possible vitreous substitute . The polymer (poly{1-vinyl-2-pyrrolidinone}) (PVP) was synthesized by free radical bulk polymerization of 1-vinyl-2-pyrrolidinone (VP) in the presence of 0.25% divinyl glycol (DVG) as a crosslinking agent . The fully hydrated polymer, containing about 98% water, was clear, transparent, autoclavable, and easily injected through a small-gauge needle with minimum fragmentation, and without changes in its optical properties . Dynamic mechanical analysis of the hydrogel indicated a covalently crosslinked elastic network both before and after injection . The resilience of hydrogel decreased after being subjected to shear stress during the injection process . A cytotoxicity bioassay of the hydrogel in vitro, using cultured mouse (Balb/ c-3T3) fibroblasts, showed cytostatic but not cytocidal effects . The hydrogel was injected into the vitreous cavity of rabbits and followed up to 4 weeks . The gel was clinically well tolerated, however opacities in the vitreous body were observed following the insertion of the gel . Histopathological examination revealed no adverse reactions to the retina, but the presence of loose polymer particles indicated the possibility of the biodegradation of the polymer . These results suggest the potential use of crosslinked PVP hydrogels as vitreous substitutes, provided that their biodegradation is not significant, a matter that should be further investigated. J Biomed Mater Res, 1996 Apr, 30(4), 429 - 9 Characterization of the cell response of cultured macrophages and fibroblasts to particles of short-chain poly{(R)-3-hydroxybutyric acid}; Saad B et al.; The known biodegradability of poly{(R)-3-hydroxybutyric acid} (PHB) in certain biological environments had led to its proposed use as a biodegradable, biocompatible polymer . Recently, a new, rapidly biodegradable block copolymer that contains crystalline domains of PHB blocks has been synthesized . During degradation of these polymers, the PHB domains are transformed in a first step into small crystalline particles of short-chain PHB . Therefore, particles of short-chain poly{(R)-3-hydroxybutyric acid} (Mn 2300) (PHB-P), as possible degradation products, are investigated here for their effects on the viability and activation of mouse macrophages (J774), primary rat peritoneal macrophages, and mouse fibroblasts (3T3), and their biodegradation or exocytosis (or both) in these cells . Results obtained in the present study indicate that incubation of macrophages with PHB-P concentrations higher than 10 micrograms/mL were found to cause a significant decrease in the number of attached and viable cells as measured in MTT assay, and significant increase in the production levels of tumor necrosis factor-alpha (TNF-alpha) or nitric oxide (NO) . At low concentrations, particles of PHB failed to induce cytotoxic effects or to activate macrophages . In addition, signs of possible biodegradation were seen in macrophages . Fibroblasts showed only limited PHB-P phagocytosis and no signs of any cellular damage or cell activation (production of collagen type I and IV, and fibronectin) . Taken collectively, the present data indicate that phagocytosis of PHB-P at high concentrations ( > 10 micrograms/mL) is dose dependent and associated with cell damage in macrophages but not in fibroblasts. J Biochem (Tokyo), 1996 Apr, 119(4), 690 - 6 A novel phenylserine dehydratase from Pseudomonas pickettii PS22: purification, characterization, and sequence of its phosphopyridoxyl peptide; Okuda H et al.; A novel phenylserine dehydratase {EC 4.2.1.-}, which catalyzes the deamination of L-threo-3-phenylserine to yield phenylpyruvate and ammonia, was purified to homogeneity from a crude extract of Pseudomonas pickettii PS22 isolated from soil . The enzyme was a monomer having a molecular mass of about 38 kDa and contained 1 mol of pyridoxal 5'-phosphate per mol of enzyme . The enzyme exhibited absorption maxima at 279 and 416 nm . No appreciable spectral change was observed over the pH range of 6.0 to 8.0 . The maximal reactivity was obtained at about pH 7.5 . The enzyme was highly specific for L-threo-3-phenylserine (Km, 0.21 mM) . L-erythro-3-Phenylserine, L-threonine, L-serine, and D-serine were inert . The enzyme was inhibited by phenylhydrazine, hydroxylamine, p-chloromercuribenzoate, and HgCl2, but not by L-isoleucine, L-threonine, or L-serine . AMP, ADP, and ATP did not affect the enzyme activity . The N-terminal amino acid sequence was not similar to those of biosynthetic and biodegradative L-threonine dehydratases and L-serine dehydratases . The isolated tryptic phosphopyridoxyl peptide, however, contained a pyridoxal 5'-phosphate-binding consensus amino acid sequence of amino acid dehydratases. J Biol Chem, 1996 Mar 8, 271(10), 5884 - 91 Molecular cloning of the full-length cDNA of (S)-hydroxynitrile lyase from Hevea brasiliensis . Functional expression in Escherichia coli and Saccharomyces cerevisiae and identification of an active site residue; Hasslacher M et al.; The full-length cDNA of (S)-hydroxynitrile lyase (Hnl) from leaves of Hevea brasiliensis (tropical rubber tree) was cloned by an immunoscreening and sequenced . Hnl from H . brasiliensis is involved in the biodegradation of cyanogenic glycosides and also catalyzes the stereospecific synthesis of aliphatic, aromatic, and heterocyclic cyanohydrins, which are important as precursors for pharmaceutical compounds . The open reading frame identified in a 1 . 1-kilobase cDNA fragment codes for a protein of 257 amino acids with a predicted molecular mass of 29.2 kDa . The derived protein sequence is closely related to the (S)-hydroxynitrile lyase from Manihot esculenta (Cassava) and also shows significant homology to two proteins of Oryza sativa with as yet unknown enzymatic function . The H . brasiliensis protein was expressed in Escherichia coli and Saccharomyces cerevisiae and isolated in an active form from the respective soluble fractions . Replacement of cysteine 81 by serine drastically reduced activity of the heterologous enzyme, suggesting a role for this amino acid residue in the catalytic action of Hnl. Biomed Chromatogr, 1996 Mar-Apr, 10(2), 60 - 4 Biodegradation of fenitrothion in soil; Roy S et al.; The biodegradation of fenitrothion (an organophosphorus pesticide) in garden soil of western Uttar Pradesh in northern India has been studied . Both natural and autoclaved soil were treated with 10 p.p.m . of fenitrothion at field capacity moisture and incubated for 90 days in glass containers at 25 and 40 degrees C . The soil samples were collected at various intervals between 0 and 90 days and analysed by HPLC for the residual pesticide and metabolites formed . At 0 days the recovery of the pesticide was 98% and the pesticide then degraded linearly with incubation time . The concentration of pesticide in the natural soil decreased with incubation time with concomitant formation of two metabolites at 25 degrees C and three metabolites at 40 degrees C . These metabolites were purified to homogeneity by HPLC and characterized by IR spectroscopy . The results showed oxidative desulphuration of the pesticide at the first step followed by hydrolytic cleavage of P-O-aryl linkage and demethylation at the second and third step, respectively. Microbiology, 1996 Feb, 142 ( Pt 2), 251 - 60 Metabolism of methanesulfonic acid involves a multicomponent monooxygenase enzyme; Higgins TP et al.; A novel methylotroph, strain M2, capable of utilizing methanesulfonic acid (MSA) as a sole source of carbon and energy was the subject of these investigations . The initial step in the biodegradative pathway of MSA in strain M2 involved an inducible NADH-specific monooxygenase enzyme (MSAMO) . Partial purification of MSAMO from cell-free extracts by ion-exchange chromatography led to the loss of MSAMO activity . Activity was restored by the mixing of three distinct protein fractions designated A, B and C . The reconstituted enzyme had a narrow substrate specificity relative to crude cell-free extracts . Addition of FAD and ferrous ions to the reconstituted enzyme complex resulted in a fivefold increase in enzyme activity, suggesting the loss of FAD and ferrous ion from the multicomponent enzyme on purification . Analysis of mutants of strain M2 defective in the metabolism of C1 compounds indicated that methanol was not an intermediate in the degradative pathway of MSA and also confirmed the involvement of a multicomponent enzyme in the degradation of MSA by methylotroph strain M2. Appl Microbiol Biotechnol, 1996 Feb, 44(6), 816 - 22 Influence of a supplementary carbon source on biodegradation of pyridine by freely suspended and immobilized Pimelobacter sp.; Rhee SK et al.; The effect of the presence of supplementary glucose or acetate on the growth and pyridine-degrading activity of freely suspended and calcium-alginate-immobilized Pimelobacter sp . was investigated . Although the supplementary carbon sources could be degraded simultaneously with pyridine, Pimelobacter sp . exhibited a preference for pyridine over supplementary carbon sources . Thus, the pyridine-degrading activity of the freely suspended cells was not decreased significantly by the addition of either glucose (1.5-6 mM) or acetate (6-24 mM) to the pyridine (6-24 mM) . In the semi-continuous immobilized cell culture, immobilized cells also exhibited a preference for pyridine over supplementary carbon sources and did not switch their substrate preference throughout the culture . Owing to a high cell concentration, the volumetric pyridine degradation rate at 24 mM pyridine in the immobilized cell culture was approximately six times higher than that in the freely suspended cell culture . Furthermore, the immobilized cells could be reused 16 times without losing their pyridine-degrading activity during the culture period tested . Taken together, the use of immobilized Pimelobacter sp . for the degradation of pyridine is quite feasible because of the preference for pyridine over supplementary carbon sources, the high volumetric pyridine degradation rate, and the reusability of immobilized cells. Ecotoxicol Environ Saf, 1996 Feb, 33(1), 88 - 99 Evaluation of respirometric data: identification of features that preclude data fitting with existing kinetic expressions; Smets BF et al.; The use of respirometric for from the evaluation of intrinsic biodegradation kinetic parameters for single organic compounds is discussed . Emphasis is placed on the preliminary assessment of the data set to determine whether it is suitable for kinetic parameter estimation . Careful preliminary examination of the data avoids attempting parameter estimation with unacceptable data . Furthermore, the use of unbiased respirometric data helps ensure that the estimated parameters truly reflect the intrinsic kinetics for biodegradation of a single substrate by the culture tested . Both experimental and theoretical oxygen uptake curves are used to illustrate how various conditions can limit the utility of a given data set . The effect of substrate inhibition, dual or multiple substrate limited growth, inaccuracies in the initial conditions assumed for curve fitting, and the use of poorly acclimated cultures are discussed . Techniques are presented which allow identification of whether a data set is unsuitable and should not be used for parameter estimation . In addition, experimental procedures which can help avoid the collection of aberrant data are discussed. Bull Environ Contam Toxicol, 1996 Feb, 56(2), 225 - 30 Seasonal atrazine contamination of drinking water in pig-breeding farm surroundings in agricultural and industrial areas of Croatia; Gojmerac T et al.; Atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) a s-triazine herbicide, has been widely used in Croatian agriculture . Due to atrazine extensive use and its biodegradation in nature within at least one year (Klassen and Kodoum 1979), atrazine residues are found in ground, surface, drain and drinking water (Vidacek et al . 1994; Gojmerac et al . 1994) . Groundwater downgradient from atrazine treated fields may show seasonal concentration peaks which could exceed the safe level (Wehtje et al . 1983) . Therefore, the use of atrazine includes permanent control of its residues in water, particularly in relation to its use as a herbicidal chemical and groundwater contamination (Graham 1991) . Furthermore, the presence of atrazine in the environment and its possible ingestion via the water, food and feed chain, may present a risk for the animal and human health . The analysis of atrazine residues in soil can be performed by either colorimetry or high performance liquid chromatography (HPLC) (Vickrey et al . 1980), and in water, soil and food by immunoassay in comparison with HPLC or gas chromatography/mass spectrometry (GS-MS) (Bushway et al . 1988; Bushway et al . 1989; Bushway et al . 1992; Thurman et al . 1990) . We describe the use of enzyme-linked immunosorbent assay (ELISA) for one-year seasonal monitoring of atrazine residues in drinking water from two differently situated pig-breeding farms (agricultural and industrial areas) in Croatia . Results obtained by ELISA were compared to those produced by HPLC. J Pharm Sci, 1996 Feb, 85(2), 150 - 4 Synthesis and in vitro transdermal penetration enhancing activity of lactam N-acetic acid esters; Michniak BB et al.; A homologous series of N-acetic acid esters of 2-pyrrolidinone and 2-piperidinone has been prepared and evaluated for its ability to enhance the skin content and flux of hydrocortisone 21-acetate in hairless mouse skin in vitro . Enhancement ratios (ER) were determined for flux (J), 24-hour diffusion cell receptor cell concentrations (Q24), and 24-h full-thickness mouse skin steroid content (SC) and compared to control values (no enhancer present) . In addition, in an attempt to abrogate toxicity, these dermal penetration enhancers were designed to have the potential for biodegradation by dermal esterases . 2-Oxopyrrolidine-alpha acetic acid dodecyl ester (5) showed the highest enhancement ratios for J (ER 67.33) and Q24 (ER 180.66) . 2-Oxopiperidine-alpha-acetic acid decyl ester (10) showed a high Q24 (ER 162.07) but a lower J (ER 12.67) . 2-Oxopyrrolidine-alpha-acetic acid decyl ester (3) showed the highest enhancement ratio for SC (ER 8.7) . The ER Q24 for 3, 5 and 10, as well as other lactam N-acetic acid esters in this work, were significantly higher than the ER found using Azone as enhancer. Biodegradation, 1996-97, 7(5), 369 - 75 Isolation from coastal sea water and characterization of bacterial strains involved in non-ionic surfactant degradation; Nguyen MH et al.; A bacterial community degrading branched alkylphenol ethoxylate (APE) was selected from coastal sea water intermittently polluted by urban sewage . This community degraded more than 99% of a standard surfactant, TRITON X 100, but I.R . analysis of the remaining compound showed the accumulation of APE2 (alkylphenol with a two units length ethoxylated chain) which seemed very recalcitrant to further biodegradation . Twenty-five strains were isolated from this community, essentially Gram negative and were related to Pseudomonas, Oceanospirillum or Deleya genera . Among these strains, only four were able to degrade APE9-10 (TRITON X 100) . They were related to the Pseudomonas genus and were of marine origin . Pure cultures performed with these strains on TRITON X 100 gave APE5 and APE4 as end products . These products were further degraded to APE2 by two other strains unable to degrade the initial surfactant. Crit Rev Ther Drug Carrier Syst, 1996, 13(3-4), 225 - 56 The role of scanning probe microscopy in drug delivery research; Shakesheff KM et al.; The success of a drug delivery system is often dependent on the surface properties of the device . These surface properties will determine the complex dynamic interfacial events that occur when the system is introduced into the aqueous environment of a patient . Development of the scanning probe microscopes has provided a number of very powerful new surface analytical techniques that are making a significant contribution to the characterization of drug delivery systems and the interfacial processes that occur when such systems are exposed to aqueous living environments . In this review, we describe the design and attributes of these instruments and discuss the impact of the techniques on a wide range of drug delivery research . The scanning probe microscopes are providing new insights into important problems concerning drug delivery, including the molecular structure of polymeric biomaterial surfaces, the conformation of target biomolecules, the influence of morphology on biodegradation, the adsorption of proteins to synthetic surfaces, and the structure and interactions of colloidal particles . As the whole field of scanning probe microscopy continues to advance, drug delivery research is set to benefit; in the final section of the review, the future potential derived from the ability to characterize new surface properties under aqueous conditions is discussed. Drug Metabol Drug Interact, 1996, 13(1), 41 - 55 Phenobarbital metabolism by hepatocytes isolated from rat; Verite P et al.; In order to test the validity of the use of hepatocytes as an alternative to studies of metabolism in live animals, phenobarbital (PB) was applied at 37 degrees C to isolated rat hepatocytes, which had been previously induced by PB . The metabolites were extracted by ethyl acetate, at various pH, and identified and evaluated by GC-MS . PB was not metabolized to p-hydroxyphenobarbital as is usually the case in living animals, but it was transformed into sulphoconjugated 2-phenyl-gamma-butyrolactone . This pathway, beta-hydroxylation of the ethyl side chain followed by lactonization, previously described as a secondary metabolic pathway occurring during intoxications, was here the only observed biodegradation . These results show that it is not possible to use hepatocytes as an alternative to live animals. Nat Toxins, 1996, 4(4), 189 - 94 Microcystin levels during 1992-95 for Lakes Sagami and Tsukui-Japan; Tsuji K et al.; Toxic cyanobacterial blooms have been frequently observed in Lakes Sagami and Tsukui, Kanagawa Prefecture, Japan, which are used as drinking and recreational water sources . As the first step toward the control and removal of cyanobacterial toxins, the present study evaluated the microcystin level in these lakes . Our established method using HPLC and LC/MS to pursue trace amounts of microcystins was applied to the determination of microcystins within cyanobacteria cells and in water . We could determine precisely the intracellular and extracellular microcystin level in the water environment during 1992-95 . Microcystins RR, LR, and YR were detected at 0.02-2.64 micrograms/L in cell-free water and at 0.02-378 micrograms/L in the cells . Although there were many cases in which microcystin concentrations in the cells exceeded the proposed guideline level (1 microgram/L), there was only one example of this happening in cell-free water samples . Because the present monitoring indicated that the amount of microcystins detected in water was much less than that estimated in cells, the release of microcystins from the cells and their stability in lake water were examined in the dark . The resulting toxins persisted at the same concentration level for 14 days and the microcystin concentrations steadily declined, showing that biodegradation using aquatic natural bacterial flora is an effective detoxification process under natural conditions. J Biomater Sci Polym Ed, 1996, 7(12), 1075 - 84 In vitro biodegradation of poly(beta-hydroxybutyrate-hydroxyvalerate) microspheres exposed to Hanks' buffer, newborn calf serum, pancreatin and synthetic gastric juice; Atkins TW et al.; Spherical BSA loaded microporous matrix type microspheres composed of P(HB-HV) blended with 20% PCL II and fabricated using 0/W emulsification with solvent evaporation have been incubated in Hanks' buffer, pH 7.4; newborn calf serum; 1.5% pancreatin and synthetic gastric juice over 30 days and their percentage weight loss (PWL) and changes in ultrastructural morphology monitored by gravimetry and SEM respectively . The greatest percentage weight loss was observed after incubation in newborn calf serum and decreased in the order newborn calf serum > pancreatin > synthetic gastric juice > Hanks' buffer . Only incubation in synthetic gastric juice and Hanks' buffer produced a significant increase in PWL with increasing theoretical percentage loading . Incubation in Hanks' buffer produced limited surface erosion leading to an increase in micropore diameter and the coalescence of micropores to from surface pits . With pancreatin, surface erosion led to the disappearance of surface micropores and a reduction in microsphere diameter . Subsequent fracturing of the microsphere surface facilitated the breakup of the matrix . In synthetic gastric juice there was little surface erosion and surface flaking and bulk erosion were responsible for the breakup of the matrix . In newborn calf serum, spherical shape was maintained despite a reduction in microsphere diameter . Bulk erosion in the form of large macroporous pits extending deep into the matrix gave the microspheres a hollow appearance . The enhanced biodegradation in NCS and significant surface erosion in pancreatin was assumed to be due to the effects of exogenous enzyme activity in addition to simple ester hydrolysis. Int J Oral Maxillofac Implants, 1996 Jan-Feb, 11(1), 55 - 66 Tissue reaction and material characteristics of four bone substitutes; Jensen SS et al.; The aim of the present study was to qualitatively and quantitatively compare the tissue reactions around four different bone substitutes used in orthopedic and craniofacial surgery . Cylinders of two bovine bone substitutes (Endobon and Bio-Oss) and two coral-derived bone substitutes (Pro Osteon 500 and Interpore 500 HA/CC) were implanted into 5-mm bur holes in rabbit tibiae . There was no difference in the amount of newly formed bone around the four biomaterials . Interpore 500 HA/CC resorbed completely, whereas the other three biomaterials did not undergo any detectable biodegradation . Bio-Oss was osseointegrated to a higher degree than the other biomaterials . Material characteristics obtained by diffuse reflectance infrared Fourier transform spectrometry analysis and energy-dispersive spectrometry did not explain the differences in biologic behavior. J Biomed Mater Res, 1996 Jan, 30(1), 85 - 94 Mechanical and biological properties of two types of bioactive bone cements containing MgO-CaO-SiO2-P2O5-CaF2 glass and glass-ceramic powder; Tamura J et al.; In this study two types of bioactive bone cement containing either MgO-CaO-SiO2-P2O5-CaF2 glass (type A) or glass-ceramic powder (type B) were made to evaluate the effect of the crystalline phases on their mechanical and biological properties . Type A bone cement was produced from glass powder and bisphenol-a-glycidyl methacrylate (BIS-GMA) resin, and type B from glass-ceramic powder containing apatite and wollastonite crystals and BIS-GMA resin . Glass or glass-ceramic powder (30, 50, 70, and 80 by wt %) was added to the cement . The compressive strength of type A (153-180 MPa) and B (167-194 MPa) cement were more than twice that of conventional polymethylmethacrylate (PMMA) cement (68 MPa) . Histological examination of rat tibiae showed that all the bioactive cements formed direct contact with the bone . A reactive layer was seen at the bone-cement interface . In specimens with type A cement the reactive layer consisted of two layers, a radiopaque outer layer (Ca-P-rich layer) and a relatively radiolucent inner layer (low-calcium-level layer) . With type B cement, although the Ca-P-rich layer was seen, the radiolucent inner layer was absent . Up to 26 weeks there was progressive bone formation around each cement (70 wt %) and no evidence of biodegradation . The mechanical and biological properties of the cements were compared with those of a previously reported bone cement containing MgO-free CaO-SiO2-P2O5-CaF2 glass powder (designated type C). Rev Environ Contam Toxicol, 1996, 147, 71 - 117 Environmental fate of rice pesticides in California; Mabury SA et al.; Each of the pesticides reviewed is reported to dissipate from field water after application . Carbofuran is hydrolyzed rapidly under the alkaline conditions usually found in the rice field environment, and its hydrolysis products are also degraded rapidly . The longest half-life reported (18-26 d) was in water that overlaid soil treated with Furadan granular formulation . Generally, carbofuran dissipation ranged from 36 hr to 3 d . Under field application, bensulfuron methyl showed a half-life of 1-3 d, but others have recovered all of the "dissipated" herbicide in the soil compartment . MCPA applied to rice fields is reportedly degraded by the joint action of sunlight and microbial action with a half-life of 3-5 d . Methyl parathion showed a maximum half-life of 9-17 d in a model aquatic ecosystem, but other reports found more rapid dissipation . The half-life of molinate has been observed by numerous researchers to be less than 5 d, with volatility the major route of loss . A half-life as short as 5-7 d has been reported for thiobencarb applied to rice fields, but others report much longer periods; volatility again is expected to be a significant route of loss . Microbial degradation takes place with each of the subject pesticides . Numerous authors have reported enhanced degradation of carbofuran under conditions of repeated application, and this probably holds true for the others . A specialized segment of the microbial population (Pseudomonas spp.) is purported to carry out most of the degradation but is inefficient at degrading the hydrolysis product, carbofuran phenol . Biodegradation of bensulfuron methyl has been observed with actinomycetes, fungi, and bacteria, and takes place primarily by oxidation and hydrolysis . Methyl parathion is biodegraded primarily by nitro reduction to aminomethyl parathion . A fungus, an actinomycete, and a bacterium were shown to biodegrade molinate, primarily by oxidation at the sulfur atom and the azepine ring . Thiobencarb is biodegraded in anaerobic sediments at a slow rate; the dechlorinated thiobencarb was shown to cause dwarfing of rice in some fields . Otherwise, its aerobic biodegradation is rapid and follows the same routes as with molinate . Carbofuran is a systemic insecticide that is rapidly absorbed and translocated to aerial parts of the plant . Carbofuran is metabolized in rice plants to the corresponding phenol, which is irreversibly bound into the plant, as well as to 3-hydroxycarbofuran and other minor components; it is depurated through leaf exudate, from which it volatilizes . Rice plants were observed to take up more bensulfuron methyl through shoots than roots and to metabolize it to the 4-hydroxy analog . The half-life of methyl parathion in Hydrilla verticulla, an aquatic macrophyte, was 1 wk, but little has been reported on methyl parathion in plants . Barnyardgrass was found to absorb greater amounts of molinate than did rice, and it produced larger proportions of basic metabolites, which may form the basis for its selective toxicity . Thiobencarb has been shown to be rapidly absorbed, translocated, and metabolized in rice plants, barnyardgrass, and the broadleaved wild amaranth, smartweed, and lambsquarters . Translocation was more rapid and extensive in barnyardgrass than in rice, and most of the 14C radiolabel was recovered as metabolites . Its terminal metabolite, chlorobenzoic acid, was taken up into lignin-like plant constituents . It is apparent that information on plant uptake and biodegradation is limited--none exists for woody species--but the fact that some species appear resistant to the herbicides suggests that biodegradative ability is general . (ABSTRACT TRUNCATED) J Biomater Sci Polym Ed, 1996, 7(9), 805 - 16 Enzymatic hydrolysis of copoly(N-hydroxypropyl-L-glutamine/L-leucine) hydrogels in vitro; Miyachi Y et al.; Two component random copolypeptide hydrogels consisting of N-hydroxyalkyl L-glutamine and L-leucine were prepared by carrying out aminolysis reactions with 3-amino-1-propanol(P) together with cross-linking reactors with 1,8-octamethylenediamine (OMDA) on hydrogels of the starting copolymers consisting of gamma-methyl-L-glutamate(M) and L-leucine(L) . The relation between their bulk structure and properties was investigated with regard to the swelling ration in water, aqueous vapor permeability, tensile properties, and enzymatic degradation behavior in a pseudoextracellular fluid (PECF) . The tensile property of the hydrogels was highly dependent on the swelling ratio in PECF, and on the hydrophobicity of the side chains, whose behavior was typical of an elastomer . It was shown that a common relation was obtained between the rate of water vapor permeabilities and the swelling ratio of hydrogels in PECF regardless of the difference of the nature of side chains . Biodegradation of the hydrogels in vitro by bromelain indicated that the degradation took place in bulk rather than on surface, and that the rate of degradation was also highly dependent on the swelling ratio of samples as well as on the hydrophobicity of the side chains of samples. Rocz Panstw Zakl Hig, 1996, 47(1), 13 - 23 {Toxicity of selected brominated aromatic compounds}; Szymanska JA; Flame retardants are added to plastic materials, textiles, wood, hydraulic liquids etc . for reducing their inflammability . These substances reduce the heat and carbon monoxide formation in case of fire . They are added in high amounts, even up to 30% of product mass (e.g . plastic material) . The production of brominated flame retardants has been steadily rising in the last 20 years, e.g . in the 1990s the world production of polybromodiphenyl ethers (PBDE) reached 40,000 tons annually . Mainly polybrominated flame retardants are produced, e.g . polybromobiphenyls (PBB), PBDE, hexabromobenzene (HBB) . Their toxicity is low or nil, the DL 50 values are over 1 g/kg . However, when administered in low doses over longer time periods they can cause changes leading to porphyria . The information on the toxicity of polybrominated flame retardants for humans is derived mainly from the accident in Michigan, where PBB contamination of fodder for farm animals occurred with consequent contamination of food . In consumers of contaminated food cutaneous changes and neurological and muscular symptoms were noted . Polybrominated flame retardants can be metabolized and undergo biodegradation mainly trough debromination . The data on the toxicity of debromination products point to di- and tribromobenzenes, some of which are highly hepatotoxic . In acute poisoning hepatocellular damage manifest itself as necrotic changes in experimental animals receiving 0.1-0.8 of DL 50 of di- or tribromobenzene . After repeated administration of lower doses the hepatocellular damage assumes the features of porphyrogenic injury . In the environment polybrominated flame retardants can be transformed by various factors (high temperature during fire accidents, incomplete incineration of waste) to polybrominated dibenzodioxins of dibenzofurans whose lethal doses can in extreme cases be 0.001 mg for 1 kg body weight. New Microbiol, 1996 Jan, 19(1), 77 - 84 Influence of environmental adaptation on the sensitivity of micromycetes to pentachlorophenol toxicity in microcosms; Onochie-Okeke BC et al.; The search for fungal strains capable of pentachlorophenol degradation led to the isolation and identification of 98 different micromycetes . When these strains were submitted to toxicity tests in aquatic microcosms at concentrations of 10 mgL-1 and 100 mgL-1 PCP, inhibition of growth was 57% and 36% respectively of the total isolated and identified strains . Among the strains inhibited at 10 mgL-1, 6 can serve as bioindicators of PCP pollution while the strains resistant can be regarded as potential PCP biodegraders . It was confirmed that fungal strains isolated from sites contaminated by chemically different products manifest different levels of sensitivity to PCP toxicity and probably different biodegradation potentials. Biomed Sci Instrum, 1996, 32, 81 - 6 Cytological evaluation of capsular tissue surrounding TCPL implant in adult rats; Benghuzzi H; Inflammatory response and the subsequent fibrous capsule formation are often used as a screening method to determine biocompatibility of an implanted material . In this study, porous implants of tricalcium phosphate-lysine (TCPL) delivery devices were implanted intraperitoneally (i.p.) and subcutaneously (s.c.) using adult male rats as a model . The fibrous capsule surrounding the implant was studied histochemically to determine the resorbability rate of the devices . Fibrous capsular tissues were carefully dissected away from the capsule noting the tissue closest to the implanted material . Evaluation of the sections (5um, H&E) collected from various areas of the implants (n = 15 per group) revealed that: (1) regardless of the site of surgical implantation, all devices were encapsulated with fibrous tissue within three days post implantation and the thickness of the capsular tissue was found to be directly proportional to duration of implantation, (2) the thickness of fibrous tissues collected from i.p . site were significantly higher than those collected from s.c . site of implantation, (3) vascularity, macrophages, multinucleated giant cells and plasma cells at the TCPL implant-interface were evident after the first week, and the persistence of these cell types and progressive angiogenesis in subsequent weeks was apparent . The formation of distinct cell layers was remarkable in the fifth week phase, (4) SEM and radiographic analysis of retrieved devices showed a significant (P < 0.05) increase in the number of macropores (12 to 36 um2) in TC