Biull Eksp Biol Med, 1984 Dec, 98(12), 675 - 8 {Mechanism of the clinical effects of UV-irradiated blood: the stimulation of DNA synthetic activity of human cells in culture}; Belisheva NK et al.; Supernatants of UV-irradiated specimens of donor whole blood, leukocyte-platelet or red cell suspensions added to human embryonic cells in vitro produce a 1.4-1.6-fold increase in 3H-thymidine incorporation into human embryonic cells . Irradiation of blood plasma without the cells by the same doses as therapeutic ones is not followed by the effect indicated . Therefore the stimulation of the growth capacity of the blood after irradiation is connected with its cells . It is suggested that the effect under discussion is derived from the release of some active components from the blood cell surface (outer perimembranous layer) because of its photochemical destruction during UV-irradiation. J Pharmacol Exp Ther, 1984 Dec, 231(3), 518 - 26 Suppression of humoral antibody production by exposure to 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin; Holsapple MP et al.; The day 4 IgM antibody (AB) response to sheep red blood cells was suppressed in adult female B6C3F1 mice subchronically (14 day) exposed to 1,2,3,6,7,8-hexachlorodibenzo-p-dioxin (1,2,3,6,7,8-HCDD) at concentrations reflecting the levels of this dioxin isomer as a contaminant in technical-grade pentachlorophenol . Hepatic microsomal parameters were also measured in these mice and indicated the characteristic induction of mixed-function oxidase enzyme activities, particularly aryl hydrocarbon hydroxylase . The response to sheep red blood cells was also suppressed when measured in vitro by culturing the antigen with spleen cells from a second group of mice subchronically exposed to 1,2,3,6,7,8-HCDD . Enumeration studies with fluorescent-labeled antisera in these animals indicated a dose-related suppression in the number of T-lymphocytes with no effect on B-lymphocytes . 1,2,3,6,7,8-HCDD directly suppressed several in vitro AB responses when added to cultures of spleen cell suspensions from untreated B6C3F1 mice . The rank order of sensitivity was determined to be: polyclonal AB response to LPS greater than or equal to T-independent AB response to DNP-Ficoll greater than T-dependent AB response to sheep red blood cells . Subsequent studies indicated that the suppression by 1,2,3,6,7,8-HCDD could be produced after only a 30-min preincubation . The suppression of all in vitro AB responses was abolished when the dioxin was preincubated with a metabolic activation system: crude liver homogenate (B6C3F1 mice pretreated with the mixed-function oxidase inducer; Aroclor 1254) plus NADP and isocitrate . The suppression of the T-dependent AB response was still evident when the metabolic activation system was heat-inactivated (as verified by an inability to activate cyclophosphamide) prior to the preincubation. Neurochem Res, 1984 Dec, 9(12), 1689 - 98 Dissociation of neonatal rat brain by dispase for preparation of primary astrocyte cultures; Frangakis MV et al.; We describe the use of the neutral protease Dispase for the dissociation of neonatal rat brain tissue for the preparation of primary monolayer astrocyte cultures . The method involves 5 to 6 successive extractions with careful separation of sedimenting, undissociated tissue . This method gives an initial cell suspension of high viability (93.7 +/- 1.7% cells exclude trypan blue) . In comparison trypsin (0.25%) dissociated tissue gave a cell suspension that showed a lower viability of 58.2 +/- 7.6% . Identical saturation densities of 1.1 to 1.2 X 10(4) cells/cm2 of the Dispase dissociated tissue . Staining for glial fibrillary acidic protein showed that 90-100% cells were positive for this astroglial marker . Thus, the use of Dispase for the initial dissociation of rat brain tissue seems to give primary astrocyte cultures which are very reproducible and homogeneous. Immunobiology, 1984 Dec, 168(3-5), 285 - 300 Langerhans cells: antigen presenting cells of the epidermis; Streilein JW et al.; While epidermis in the skin provides an excellent barrier to the environment, it is an incomplete one . Some antigenic material can penetrate through the stratum corneum (or be introduced pathologically) where strategically placed epidermal Langerhans cells reside . In this review, we have assembled relevant data concerning the antigen presenting potential of epidermal Langerhans cells . Strong circumstantial evidence derived from in vitro studies of epidermal cell suspensions enriched for Langerhans cells indicates that Langerhans cells possess this capability . In vivo studies with intact skin indicate that critical numbers of functioning Langerhans cells are essential for successful induction of contact hypersensitivity by epicutaneously applied haptens . And within the past several months, experiments with purified preparations of epidermal Langerhans cells have proven that these cells, and perhaps they alone among epidermal cells, possess the capacity of processing and presenting haptenic determinants to the immune system . The challenge for the future is to determine the extent to which this unique property of Langerhans cells affords physiologic protection to the skin and under what pathologic circumstances altered Langerhans cell function leads to disease. J Clin Chem Clin Biochem, 1984 Dec, 22(12), 935 - 42 Automated flow-cytometric identification of colo-rectal tumour cells by simultaneous DNA, CEA-antibody and cell volume measurements; Valet G et al.; A new method for the automated flow-cytometric identification of colo-rectal tumour cells was developed . Fresh tissue is cut mechanically to obtain single cell suspensions . The cells are then incubated with antibodies in an indirect immunofluorescence assay for CEA (carcino-embryonic antigen) on the cell surface, and counterstained with the DNA stain propidium iodide . Monosized latex particles are added as internal standard, then cell volume, antibody fluorescence and DNA are measured simultaneously in a FLUVO-METRICELL flow cytometer . A FORTRAN IV computer program was used to determine whether aneuploid cells or cells with high density of CEA on their surface were present in the sample . All relevant data were stored automatically in a self updating data base, which is important for quality control and automated thresholding . The samples were taken from 120 different patients . A tumour sample and a sample of healthy adjacent mucosa of the same patient were available in 88 patients . 97.5% of all tumours and 88.6% of the normal mucosa samples were correctly identified . This shows for the first time that the majority of colo-rectal tumour samples can be identified by a flow cytometric measurement with automated data evaluation . The identification of tumour samples was substantially better when based on the measurement of the three parameters, compared with identification by aneuploidy (59%) or by the CEA antibody alone (91%) . It will be possible to automate the measurement of the samples. J Bacteriol, 1984 Dec, 160(3), 943 - 8 Spectrophotometric determination of affinities of peptides for their transport systems in Escherichia coli; Perry D et al.; The use of novel synthetic peptides to measure peptide transport by spectrophotometric means is described . These peptides contain glycine residues alpha-substituted with thiophenol and are recognized as substrates by both peptide transport systems and intracellular peptidases of Escherichia coli (Kingsbury et al., Gilvarg, C., Proc . Natl . Acad . Sci . U.S.A . 81:4573-4576, 1984) . Transport and peptidase cleavage results in the intracellular release of thiophenol, which exits rapidly from the cell . The release of thiophenol from these peptides by cell suspensions can be measured with Ellman sulfhydryl reagent {5,5'-dithiobis(2-nitrobenzoic acid)} and provides a direct determination of the rate of peptide transport . The reductions in thiophenol release from these peptides resulting from the addition of peptide competitors enable the affinities of the competitors for their transport systems to be determined . By this method, it is shown that the dipeptide transport system is more restrictive with respect to changes in the amino acid sidechains of its substrates than those of the oligopeptide transport system. Immunobiology, 1984 Dec, 168(3-5), 313 - 24 The Langerhans cell, as a representative of the accessory cell system, in health and disease; Thorbecke GJ et al.; Cell surface receptors and antigens present on Langerhans' cells (LC) suggest a close relationship between LC and interdigitating cells (IDC) in lymph node sections or lymphoid dendritic cells (LDC) in cell suspensions . One of the reported differences is that Fc receptors (FcR) which are present on LC, are absent on LDC . This difference can at least partly be explained by a laboratory artefact: FcR on murine LC are irreversibly modulated by the Ig that contaminates the bovine albumin commonly used for gradients . Furthermore, the demonstration of FcR on murine LC requires prolonged exposure to EA at 4 degrees C . A significant percentage of nonadherent, low density, Ig- lymph node cells also express such FcR . These cells can stimulate syngeneic mixed lymphocyte reactions as can LC isolated from epidermis . Consideration of LC as cutaneous representatives of the accessory cell system led to an investigation of their numbers in epidermal sheets of patients with acquired immunodeficiency syndrome (AIDS) . A marked reduction in Ia+, ATPase+, OKT6+ LC was found as compared to controls, suggesting that accessory cell deficiency may play a role in the extreme immunodeficiency seen in AIDS patients. Lab Invest, 1984 Dec, 51(6), 635 - 42 Induction of neovascularization in vivo and endothelial proliferation in vitro by tumor-associated macrophages; Polverini PJ et al.; The role of macrophages in neovascularization of tumors was investigated by examining the ability of tumor-associated macrophages (TAM) and their conditioned culture media to induce neovascularization in the cornea of syngeneic rats and proliferation of bovine aortic endothelial cells in culture . TAM were isolated from a 3-methycholanthrene-induced fibrosarcoma propagated in F344 male rats by enzymatic dissociation and were purified by centrifugation through continuous Percoll density gradients, followed by adherence to fibronectin-coated dermal collagen gels . The angiogenic potential of (a) TAM and their 72-hour conditioned culture media, (b) whole tumor cell suspensions (WTCS), (c) tumor cell suspensions depleted of TAM (TCS), and (d) macrophage-depleted tumor cell suspensions reconstituted with TAM (TCS + TAM) were compared . Cells were injected directly; conditioned media were concentrated 10-fold, incorporated into slow-release Hydron pellets, and implanted intracorneally . Stimulation of bovine aortic endothelial cell growth by TAM was assayed in culture with TAM-conditioned media and compared with responses induced by conditioned media from peptone-elicited rat peritoneal exudate macrophages . TAM and their conditioned media induced neovascularization in 38 of 40 corneas (95%) and 15 of 17 corneas (88%), respectively . Maximal vessel ingrowth occurred by the 5th day of implantation . Neovascular responses induced by WTCS (24 of 26 corneas, 92%) and TCS (17 of 24 corneas, 71%) occurred on the 7th and 10th day, respectively . TCS + TAM induced neovascular responses comparable to those elicited by WTCS (19 of 20 corneas, 95%) . Addition of TAM-conditioned media to bovine aortic endothelial cell cultures stimulated a 10-fold increase in cell number within 10 days . This growth stimulatory effect was comparable to or greater than responses induced by conditioned media from rat peritoneal macrophages . Our results demonstrate that TAM are potent stimulators of neovascularization and endothelial cell proliferation and that depletion of macrophages from tumor cell suspensions significantly decreased their angiogenic potential . This suggests that neovascularization of this tumor is mediated in part by macrophages. Cancer Res, 1984 Dec, 44(12 Pt 1), 5718 - 24 Isolation of preneoplastic rat liver cells by centrifugal elutriation and binding to asialofetuin; Evarts RP et al.; Putative preneoplastic hepatocytes were isolated from male Fischer 344 rats treated with a single dose of diethylnitrosamine, 2-acetylaminofluorene feeding, and partial hepatectomy (Solt-Farber model) . The isolation procedure involved, after collagenase dispersion of the liver, separation of the hepatocytes into small- and large-cell fractions by centrifugal elutriation, and subsequent selection of cells deficient in asialoglycoprotein receptor(s) by plating onto asialofetuin (ASF)-coated plates . The number of cell surface binding sites for the asialoglycoprotein receptor was measured with both asialoorosomucoid and ASF as ligands . There was a 50% reduction of binding sites for both ligands in the original cell suspensions obtained from preneoplastic livers . The reduction in receptor binding sites was most pronounced in the large cell fraction (less than or equal to 30% of control value) after separating the original cell suspension by elutriation into small and large cell fractions . Immunohistochemical studies showed a lack of asialoglycoprotein receptor in preneoplastic (i.e., hyperplastic foci) areas . These areas were entirely super-imposable with glucose-6-phosphatase-deficient areas and partially overlapped the gamma-glutamyltranspeptidase-positive areas in serial liver sections . The attachment of preneoplastic hepatocytes to ASF-coated tissue culture dishes was greatly impaired, and the number of gamma-glutamyltranspeptidase-positive cells on the ASF dishes was reduced to less than 7% as compared to 45 to 70% on the collagen-coated plates . Thus, the lack of asialoglycoprotein (asialofetuin) surface receptors and the increased size of the early preneoplastic hepatocytes are characteristics that can be used to separate the preneoplastic cell population from normal liver cells. Southeast Asian J Trop Med Public Health, 1984 Dec, 15(4), 547 - 53 Application of peroxidase-antiperoxidase (PAP) staining for detection and localization of dengue-2 antigen . I . In an endogenous peroxidase containing cell systems; Churdboonchart V et al.; The unlabelled immunoperoxidase, peroxidase-anti-peroxidase (PAP), technique was used to detect dengue type-2 viral antigen in several cell systems including the endogenous peroxidase containing cells . These cells are the mosquito cell line (C6/36), continuous cell line of rhesus monkey kidney (LLC-MK2), human monocyte culture both cell suspension and monolayer, and human peripheral blood leukocytes . All of these specimens gave the same results that dengue-2 viral antigen presented in cytoplasm only and the patterns of marker presentation in positive cells varied depending on the duration after infection . The sensitivity of this method is extremely high since it can detect dengue-2 antigen after its attachment on mosquito cells (15 min) as seen in experiments with mosquito cell line, C6/36 . False positive was not observed in all cell systems tested. J Hypertens Suppl, 1984 Dec, 2(3), S293 - 5 Inhibition of aldosterone production by atrial natriuretic factor; Atarashi K et al.; Extracts of rat atrial muscle lowered basal aldosterone release from rat adrenal glomerulosa cell suspensions, and partially inhibited the stimulation of aldosterone release by adrenocorticotropic hormone (ACTH) and angiotensin II . Atriopeptin I, an atrial peptide with natriuretic, diuretic and smooth muscle relaxant activities, significantly decreased basal aldosterone release at 1 pM concentrations . Also, atriopeptin I decreased the sensitivity of the glomerulosa cells to adrenocorticotropin and angiotensin II . These data suggest that peptides contained in mammalian atria affect sodium excretion not only by a direct effect on the kidney, but also indirectly through inhibition of aldosterone production. J Reprod Immunol, 1984 Dec, 6(6), 377 - 91 Evaluation of human chorionic trophoblast cells and placental macrophages as stimulators of maternal lymphocyte proliferation in vitro; Hunt JS et al.; Dispersed cell suspensions of human chorion membrane and placentae were obtained by enzyme digestion and the cells examined for HLA expression and for the ability to stimulate immune cell proliferation in vitro . Chorion cells with the characteristics of trophoblast were HLA-A, B, C and Ia negative following tissue digestion whereas placental cells, primarily Fc gamma R positive macrophages, were HLA-A, B, C positive and were frequently Ia positive . When chorion and placental cell suspensions were used as stimulator cells in one-way mixed cell cultures (MCC) with maternal mononuclear leukocytes (MNL) as responder cells, chorion cells were not normally stimulatory (mean stimulation index (SI), 2.7) whereas placental cells usually were (mean SI, 11.5) . No evidence for active suppression by chorion cells was obtained in a group of experiments designed to detect suppressive activity . The results support the concept of the trophoblast layer as an immunologically inert barrier between the mother and the fetus. Surgery, 1984 Dec, 96(6), 1019 - 26 Failure of secretin to stimulate gastrin release and adenylate cyclase activity in gastrinoma in vitro; Ellison EC et al.; It has been hypothesized that secretin may act directly on gastrinoma through the adenylate cyclase system to cause stimulation of gastrin release . We studied gastrinoma cells in vitro to determine whether secretin would stimulate gastrin release directly and whether the gastrinoma cell membrane had a functional secretin receptor adenylate cyclase system . Fresh tumor was prepared in cell suspensions containing 1.5 X 10(6) viable cells and incubated for 2 hours with either 2 mM CaCl2 alone (control) or 2 mM CaCL2 and 0.025 U/ml secretin . The gastrin content of the cells in each incubation chamber and the medium were determined by radioimmunoassay and results were expressed as mean gastrin pg/microgram protein +/- SD . Under basal conditions the cellular gastrin content was 39.9 +/- 6.4 (control) compared with 16.7 +/- 2.1 (secretin) . After 2 hours of incubation, cellular gastrin content increased in both groups: 68.5 +/- 11.9 (control) to 68.3 +/- 5.5 (secretin) . However, the percent of gastrin released into the medium during incubation decreased by one half in both groups (control 37.3% +/- 4.0% to 22.2% +/- 3.0%; secretin 42.8% +/- 7.0% to 18.9% +/- 1.8%) . Adenylate cyclase activity was assessed by measuring cAMP generation in fresh-frozen gastrinoma and cultured gastrinoma cell membranes . Isoproterenol (10(-5) M), PGE1 (10(-4) M), and GppNHp (guanine nucleotide) (10(-5) M) caused fivefold to 25-fold increases in cAMP generation . Secretin did not stimulate adenylate cyclase activity above basal (21.73 +/- 4.07 and 2.29 +/- 1.2 pmol cAMP/mg protein/min) for frozen and cultured gastrinoma, respectively . Secretin failed to stimulate gastrin release and adenylate cyclase in vitro . This suggests that secretin-stimulated gastrin release in vivo may not be due to a direct effect of secretin on the gastrinoma. J Pharmacol Exp Ther, 1984 Dec, 231(3), 527 - 31 Kinetics of the enhancing effect produced by norepinephrine and terbutaline on the murine primary antibody response in vitro; Sanders VM et al.; Experiments were performed to determine the minimal drug exposure time required for norepinephrine and a relatively selective beta-2 adrenoceptor agonist to produce a maximal enhancing effect on the murine primary antibody response in vitro . The antibody response was determined by counting the number of spleen cells producing immunoglobulin M antibody directed against sheep erythrocytes 5 days after exposure of spleen cells to antigen and drugs . Norepinephrine (10(-5) M) or terbutaline (10(-5) M) were added to mouse spleen cell suspensions at the time of immunization with sheep erythrocytes on day 0 . Phentolamine (10(-5) M) and/or propranolol (10(-6) M) were added to the spleen cell cultures to block adrenoceptor activation either at the time of agonist exposure (time = 0 hr) or at various times after agonist exposure (time = 15 min-96 hr) . The addition of adrenoceptor antagonists at times after agonist exposure allowed for determination of the minimal time required for adrenoceptor activation to produce a maximally enhanced antibody response . Norepinephrine and terbutaline produced a maximally enhanced antibody response, as measured 5 days later, after 5 to 6 hr of agonist exposure before the addition of the antagonists . Addition of the antagonists at times later than 5 to 6 hr after agonist had no effect on the maximal antibody response . When antagonists were added before this time, the magnitude of the enhancing effect attained was time-dependent . These results indicate that early adrenoceptor activation in vitro is responsible for initiating events which culminate in an enhanced primary antibody response measured a number of days after drug exposure. Endocrinology, 1984 Dec, 115(6), 2464 - 72 Self-suppression of corticosteroidogenesis: evidence for a role of adrenal 5 alpha-reductase; Carsia RV et al.; Exogenous corticosterone (B), the natural glucocorticoid product of rats, suppressed endogenous B production of isolated rat adrenocortical cells induced by alpha ACTH-(1-24), {9-tryptophan (O-nitrophenylsulfenyl)}ACTH-(1-24) {( Trp (Nps)9}ACTH-(1-24}, and cAMP as well as pregnenolone supported-steroidogenesis . This self-suppression occurred within 2 h . It was dependent on the concentration of exogenous B . However, self-suppression did not alter the half-maximal steroidogenic concentration (ED50) of each steroidogenic agent . In addition, exogenous B did not suppress ACTH-induced cAMP production or gross protein synthesis, as measured by leucine incorporation into bulk cellular proteins . These results with isolated cells suggested at least two mechanisms for self-suppression: 1) exogenous B inhibited steroidogenic steps in a noncompetitive manner, and/or 2) exogenous B induced B degradation . In this study we examined the effect of exogenous B on the degradation of B . Accordingly, we measured the adrenal 5 alpha-reductase activity (5 alpha RA) of cell homogenates prepared from treated cells . Isolated adrenocortical cells were incubated for 2 h with alpha ACTH-(1-24), ovine PRL (oPRL), and B . They were then homogenized and assayed for 5 alpha RA, as indicated by the disappearance of exogenous B, as shown by RIA . In addition, the percentage of exogenous tritium-labeled B {( 3H}B) converted to 5 alpha-dihydrocorticosterone (DHB), the principal reduced metabolite of B, was determined by TLC . Isolated adrenocortical cells from intact rats showed insignificant 5 alpha RA and DHB formation when incubated with or without alpha ACTH-(1-24) and with or without oPRL . However, with exogenous B, there was significant 5 alpha RA and DHB formation . oPRL plus B decreased DHB formation . The effects of B and oPRL were more demonstrable with cells from hypophysectomized rats . These cells exhibited high 5 alpha RA and DHB formation; exogenous B increased these values, whereas oPRL acutely reversed the effects of hypophysectomy and exogenous B . In other work avoiding cell homogenization, exogenous B suppressed ACTH-induced B accumulation and increased DHB formation in intact cell suspensions from intact rats and intact male domestic fowl . Furthermore, exogenous B increased the conversion of {3H} pregnenolone to DHB in intact cell suspensions from intact rats, showing that B synthesized de novo as well as exogenous B can be degraded during self-suppression . These data indicate that acute self-suppression of corticosteroidogenesis is at least partly mediated by an increase in 5 alpha RA. Biol Reprod, 1984 Dec, 31(5), 1037 - 48 Serological and biochemical identification of a plasma membrane antigen specific to Leydig cells; Millette CF et al.; Purified mouse Leydig cells have been prepared from interstitial cell suspensions using a Percoll gradient procedure . The isolated cells are 88-95% pure as determined by light microscopy . Staining for 3-beta-hydroxysteroid dehydrogenase indicates that over 85% of the Leydig cells recognized by differential interference microscopy are also positive for this enzyme . After separation, the Leydig cells are viable by dye exclusion assays and exhibit normal in situ morphology when examined at the ultrastructural level . Leydig cell suspensions have been used to raise a polyclonal antiserum in rabbits . This antiserum, prior to absorption, reacts in indirect immunofluorescent studies with the surfaces of isolated Leydig cells, with testicular germ cells, with spermatozoa and with somatic cells such as splenocytes . Following absorption with lymphocytes and spermatogenic cells, the antiserum binds only to Leydig cell plasma membranes . Quantitative measurements with 125I-protein A confirm the specific labeling of Leydig cells by the absorbed antiserum . Biochemical identification of the Leydig cell plasma membrane antigen has been accomplished by immunoblotting polyacrylamide gel nitrocellulose transfers . A single major band of Mr approximately 40,000 is detected on one-dimensional transfers; two weakly reactive spots of Mr 43,000 and 45,000 are detected using two-dimensional immunoblots . Blotting experiments conducted using concanavalin A have identified the major Leydig cell constituents reactive with this lectin . The Leydig cell plasma membrane antigen(s) does not bind concanavalin A. J Immunol Methods, 1984 Nov 30, 74(2), 375 - 84 A simple rapid method for detection of IL-2 in a physiological medium; De Vos C et al.; The Con A-activated proliferation of C57BL/6 mice thymus cell suspension is completely blocked by a low concentration of hydrocortisone . This inhibition is reversed by the addition of a 24 h Con A-activated splenic cell supernatant to the thymic cell culture . The restoring activity is completely destroyed by heating . Restoration is not obtained by addition of IL-1-rich supernatant from an LPS-activated peritoneal adherent cell population . The supernatant of a 24 h splenic cell culture activated by Con A in the presence of indomethacin not only restores hydrocortisone-blocked thymocyte reactivity but also enhances thymic cell stimulation . Addition of PGE to the splenic cell culture inhibits the restoring potency of the supernatant . These results are in accord with the proposition that IL-2 is responsible for the restoring phenomenon . These properties have been used to develop a semi-quantitative method for detection of IL-2 in a physiological medium. J Immunol Methods, 1984 Nov 30, 74(2), 317 - 25 Removal of rat dendritic cells from single cell suspensions by passage through columns of Sephadex G-10; Bowers WE et al.; Rat T lymphocytes require dendritic cells as accessory cells in order to respond to the mitogen sodium periodate . Passage of a lymph node cell suspension through a column of Sephadex G-10 reduced the mitogenic response by greater than 90%, despite a cell recovery of 75% . An even greater reduction in the response occurred after a second passage over Sephadex G-10; addition of purified dendritic cells restored the response . Lymph node cell suspensions and preparations enriched in dendritic cells were nearly depleted of these cells by passage over Sephadex G-10 . After passage of lymph node cells over Sephadex G-10, a limited number of retained cells could be recovered; these included both dendritic cells and macrophages . Enumeration of macrophages in the various passed and retained fractions by non-specific esterase staining of smears confirmed that macrophages were effectively removed from lymph node cell suspensions by repeated passage over Sephadex G-10 . Cell preparations that pass through Sephadex G-10 are therefore depleted of both dendritic cells and macrophages. Biochim Biophys Acta, 1984 Nov 21, 778(1), 185 - 90 Effect of thiourea on PCMBS inhibition of osmotic water transport in human red cells; Chasan B et al.; The organomercurial reagent p-chloromercuribenzene sulfonate (PCMBS) is an inhibitor of osmotic water permeability in the human red cell membrane . We have found that thiourea, when added along with PCMBS to a red cell suspension, interferes with this inhibition and at high enough concentrations prevents the inhibition from developing altogether . For a 2 mM PCMBS concentration Ki = 3 +/- 1 mM . When thiourea is added at a later time, the PCMBS inhibition, which normally takes about 20 min to develop fully, is halted and remains fixed at the value attained by that time . Thiourea also inhibits the reversal of PCMBS inhibition by a 10 mM concentration of cysteine, the half-time for reversal increasing by more than an order of magnitude when {thiourea} = 50 mM . Possible implications for the nature of the water and urea transport pathways across the red cell membrane are discussed. J Immunol Methods, 1984 Nov 16, 74(1), 31 - 8 Intracellular fluorescent labelling of cells for analysis of lymphocyte migration; Brenan M et al.; A procedure for analysing in vivo migration of lymphocytes labelled in vitro using intracellular fluorochromes is described . Comparison of carboxyfluorescein diacetate, a cytoplasmic label, with Hoechst dye No . 33342 (H33342), a DNA-binding fluorochrome, indicated that H33342 is superior . The concentration of H33342 used for labelling does not significantly affect viability or lymphocyte migration and permits long-term visualization . H33342 allows quantitation of in vivo migration in cell suspension and histological localization in frozen sections . Fluorescence is retained in fixed frozen sections for at least 3 months . This method can be used for analyses of lymphocyte migration and maturation. Eur J Biochem, 1984 Nov 15, 145(1), 195 - 202 Induction of chalcone isomerase in elicitor-treated bean cells . Comparison of rates of synthesis and appearance of immunodetectable enzyme; Robbins MP et al.; Chalcone isomerase, an enzyme involved in the formation of flavonoid-derived compounds in plants, has been purified nearly 600-fold from cell suspension cultures of dwarf French bean (Phaseolus vulgaris L.) . Chromatofocussing yielded a single form of the enzyme of apparent pI 5.0 . This preparation was used to raise rabbit anti-(chalcone isomerase) serum . Changes in the rate of synthesis of chalcone isomerase have been investigated by indirect immunoprecipitation of enzyme labelled in vivo with {35S}methionine in elicitor-treated cultures of P . vulgaris . Elicitor, heat-released from cell walls of the phytopathogenic fungus Colletotrichum lindemuthianum, the causal agent of anthracnose disease of bean, causes increased synthesis of the isomerase, with maximum synthetic rate occurring 11-12 h after exposure to elicitor . Immune blotting studies indicate that the elicitor-mediated increase in extractable activity of the isomerase is associated with increased appearance of immunodetactable isomerase protein of Mr 27 000 . However, the maximum level of immunodetectable isomerase was attained approximately 6 h earlier than maximum extractable activity . Furthermore, a 2.8-fold increase in enzyme activity above basal levels at 12 h after elicitor-treatment was associated with a corresponding 5.8-fold increase in immunodetectable enzyme . It is concluded that elicitor induces the synthesis of both active and inactive chalcone isomerase of Mr 27 000, and that some activation of inactive enzyme occurs during the elicitor-mediated increase in isomerase activity . The presence of a pool of inactive chalcone isomerase in bean cell cultures has recently been suggested on the basis of density labelling experiments utilising 2H from 2H2O {Dixon et al . (1983) Planta (Berl.) 159, 561-569}. Biochemistry, 1984 Nov 6, 23(23), 5549 - 55 Measurement of intracellular pH and deoxyhemoglobin concentration in deoxygenated erythrocytes by phosphorus-31 nuclear magnetic resonance; Labotka RJ; Deoxygenation of erythrocytes produced marked changes in their 31P nuclear magnetic resonance spectra in the superconducting spectrometer . Most significantly, all intracellular and extracellular phosphates underwent downfield shifts . In fully deoxygenated blood the extracellular phosphates showed downfield shifts that were dependent upon packed cell volume, when added pyrophosphate was used as a measure of extracellular chemical shift behavior . This effect on extracellular signals was attributed to the paramagnetic contribution of deoxyhemoglobin to the "bulk" magnetic susceptibility of the red cell suspension . Line broadening was observed in deoxygenated whole cell systems but not in hemolysates, as a result of paramagnetic susceptibility gradients across the cell membrane . The degree of downfield shift upon deoxygenation was of different magnitude for each intracellular phosphate {2-P of 2,3-diphosphoglycerate (2,3-DPG) greater than 3-P of 2,3-DPG greater than inorganic phosphate greater than ATP phosphates}, independent of packed cell volume but dependent on the degree of deoxygenation of hemoglobin . When deoxygenation shift effects in adult cells were compared to those of cord blood cells containing 70% fetal hemoglobin, it was found that 45% of the 2,3-DPG shift effects were attributable to binding of that compound to hemoglobin . By use of a nonphysiologic phosphate analogue, methylphosphonate, as an internal reference, it was found that an increase in pH of deoxy cells contributed to the downfield shift of inorganic phosphate . In hemolysates, the methylphosphonate - inorganic phosphate chemical shift difference was found to be pH dependent, with a sensitivity of (-) 0.39 pH unit/ppm, independent of the hemoglobin oxygenation state. J Natl Cancer Inst, 1984 Nov, 73(5), 1119 - 24 Mammary carcinoma arising in mice undergoing a chronic graft-versus-host reaction; Gartner JG et al.; A graft-versus-host reaction (GVHR) was induced in 30 (CBA X A)F1 mice by the iv injection of 50 X 10(6) parental strain A lymphoid cells . Solid tumors emerged in 5 of 10 experimental animals that survived beyond 14 months after the GVHR was initiated . The neoplasms were judged to be mammary carcinomas by light and electron microscopic examinations . C-type RNA viral structures were observed in some tumor cells . The neoplasms were successfully transplanted into syngeneic animals by either sc or ip injections of tumor cell suspensions . Tumor transfer to syngeneic mice was not possible if only spleen cells from tumor-bearing animals were transferred . No tumors developed in an age-matched control group that received no treatment. Hokkaido Igaku Zasshi, 1984 Nov, 59(6), 762 - 74 {Studies on the sensitivity test of anticancer agents with special reference to double layer colony forming assay}; Ohsaki Y et al.; The necessity to assess the effect of chemotherapeutic agents on the patients beforehand treatment has been stressed . In 1977, Salmon & Hamburger developed a new method to evaluate the drug sensitivity using cell suspension derived from the patients . They called the method as "human tumor stem cell assay" . Since then, many reports were published about the correlation between the clinical outcomes and the results of human tumor stem cell assay, and high relationship between them was documented . The present study was undertaken to evaluate the method using the modified system; double layer colony forming assay, cell growth curve, tritiated thymidine uptake and flow cytometry . The drugs used in this study were adriamycin (ADR) and cis-platinum (C-DDP) . We chose the human small cell lung cancer cell line PC-6 as a target cell . The conclusions are follows . The effects of ADR and C-DDP were concentration dependent respectively . The time dependent effect of C-DDP on PC-6 was revealed by enhancement of lethal effect, when they were exposed to the drug for 24 hours . A possibility exists that reproductive death would take place among PC-6 by ADR, along with DNA injury . It is one of the explanations for reduction of colony formation in contrast to increase in cell number . The effect of C-DDP on PC-6 was diminished with time . This phenomenon was reflected on double layer colony forming assay, and was possible explanation for reduction of colony formation which was greater than that of expected from cell growth curve.(ABSTRACT TRUNCATED AT 250 WORDS) J Gen Microbiol, 1984 Nov, 130 ( Pt 11), 2865 - 71 Transport of alpha-aminoisobutyrate into Trypanosoma brucei brucei; Coolbear KP et al.; The uptake of alpha-aminoisobutyrate (AIB) by washed cell suspensions of bloodstream forms of Trypanosoma brucei brucei has been shown to be an energy-dependent process . No metabolism of AIB was detected under conditions leading to a 100-fold accumulation of AIB within the organism . Kinetic studies revealed that AIB uptake involved two components; that operating at low substrate concentrations had an apparent Km of 4.6 mM . Experiments with ionophores such as gramicidin and carbonylcyanide m-chlorophenylhydrazone were consistent with the AIB uptake system operating as a H+-symporter responding to the electrochemical gradient of H+, the major component of which was the membrane potential. Andrologia, 1984 Nov-Dec, 16(6), 517 - 24 Human testicular cell suspensions in vitro using post mortem material; Dietrich AJ; A method is described for culturing human testicular cells from post mortem material for at least 10 days in a serum free medium . The success of the technique is based on the fact that a layer of testicular cells remains undisturbed on the bottom of a culture flask during culturing and the medium is constantly renewed by a perfusion flow . It is shown that cells form junctions within several hours allowing metabolic coupling, indicating active survival of cells during culture period. Br J Haematol, 1984 Nov, 58(3), 465 - 72 Isolation of normal human megakaryocytes; Sitar G; This paper reports a simple procedure for obtaining human megakaryocytes with a high purification and high recovery yield . Bone marrow cells, obtained from surgically removed ribs, were separated by a two-step procedure . Initially, a single cell suspension was enriched in megakaryocytes by equilibrium density centrifugation, the low density cell fraction was subsequently layered over a shallow continuous albumin gradient in a glass sedimentation chamber . Megakaryocytes averaged 0.03 +/- 0.02% of all nucleated cells in the starting marrow cell suspension, after this procedure an average 80 +/- 15% of the initial megakaryocyte population was recovered with a purity of 94 +/- 4% . Previous methods, based upon the use of a two-step procedure, are reviewed . The theory of velocity sedimentation is discussed with regard to the differences in the methodology used, which account for the different results I obtained. Radiat Res, 1984 Nov, 100(2), 328 - 39 Reduced oxygen enhancement ratio at low doses of ionizing radiation; Palcic B et al.; A decreased oxygen enhancement ratio (OER) at lower radiation doses has been previously reported (B . Palcic, J . W . Brosing, and L . D . Skarsgard, Br . J . Cancer 46, 980-984 (1984} . The question remained whether or not this effect is due to a possible oxygen contamination at low doses, which was not the case at high doses . To ensure a sufficient degree of hypoxia prior to the start of irradiation, Chinese hamster cells (CHO) were made hypoxic by gas exchange combined with metabolic consumption of oxygen at 37 degrees C . At the same time oxygen levels in cell suspension were measured using a Clark electrode . It was found that under experimental conditions used in this laboratory for hypoxic irradiations, the oxygen levels before the start of irradiation are always below the levels which could give any significant enhancement to radiation inactivation by X rays . Full survival curves were determined in the dose range 0-30 Gy using the conventional survival assay and in the dose range 0-3 Gy using the low dose survival assay . The results confirmed the earlier finding that the OER decreases at low doses . It is therefore believed that the dose-dependent OER is a true radiobiological phenomenon and not an artifact of the experimental method used in the low dose survival assay. J Surg Res, 1984 Nov, 37(5), 354 - 60 The use of pig mononuclear cells to inhibit pulmonary tumor formation in isogenic mice; Khezri AA et al.; A-strain mice received 1 X 10(5) A-strain mammary carcinoma, B72, cells iv on Day 0 . At the same time fragments of the same tumor were implanted into the ileal mesentery of a pig together with fragments of cellulose sponge . The middle third of the pig mesenteric lymph node chain was resected . Sponge fragments of equivalent size, shape, and total weight were implanted alone into the jejunal mesentery . Seven days later, separate cell suspensions were made from the (disconnected) proximal (nonimmune) and distal (tumor-immune) segments of lymph node chain . Cells were also expressed by digital pressure from the sponges removed from the jejunal (nonimmune) and ileal (immune) segments of mesentery . A comparison was made between the antitumor action of immune lymph node cells and the two categories of sponge cell . Cells (4 X 10(6} were injected iv into the mice on Day 7 and the number of pulmonary tumors counted after killing the mice on Day 14 . Cells obtained from the "immune" sponges were significantly more effective in reducing the number of pulmonary tumors than cells from the "nonimmune" sponge, or from the immune lymph nodes . The antitumor action of all cell suspension was abolished when 4 X 10(6) cells from the "interface" layer, following centrifugation on a Ficoll-triosil column, were injected into the mice . Antitumor activity was found to be correlated with the presence of "blast" cells in the pig mononuclear cell suspensions. J Exp Med, 1984 Nov 1, 160(5), 1273 - 83 Dual origin of mouse spleen macrophages; van Furth R et al.; The present study concerns the isolation, characterization, origin, and kinetics of spleen macrophages . The spleen was first perfused in situ to remove monocytes from the vascular bed and then dissected and treated with collagenase . The macrophages in the cell suspension thus obtained were characterized morphologically and cytochemically and then quantitated . The spleen cell suspension was incubated for 24 h in Leighton tubes to obtain an enriched glass-adherent population of macrophages for characterization and {3H}thymidine-labeling studies . Almost all of the adhering macrophages were esterase positive, had Fc and C3b receptors, and ingested EIgG and opsonized bacteria . In vitro labeling with {3H}thymidine showed that approximately 5% of the mononuclear phagocytes in the spleen synthesize DNA and must be considered to be dividing cells . The course of the number of labeled monocytes and macrophages after a single injection of {3H}thymidine indicates migration of monocytes into the spleen, where they become macrophages . Calculation of the influx of monocytes into the spleen and of the local production of macrophages by DNA-synthesizing mononuclear phagocytes showed that under steady-state conditions, 55% of the population of spleen macrophages is supplied by monocyte influx and 45% by local production . This means that there is a dual origin of spleen macrophages . The mean turnover time calculated with the value for the efflux of spleen macrophages is 6.0 d. J Invest Dermatol, 1984 Nov, 83(5), 370 - 6 Selective cultivation of human melanocytes from newborn and adult epidermis; Gilchrest BA et al.; Development of adequate culture systems for the human epidermal melanocyte is critical to further advances in pigment cell biology . We now report selective growth and long-term maintenance of melanocytes derived from both newborn and adult skin specimens . Disaggregated epidermal cell suspensions were plated in a hormone-supplemented medium containing cholera toxin and a hypothalamic extract treated to remove keratinocyte growth-promoting activity . After 3-4 weeks, pure melanocyte populations could be harvested and serially passaged up to 6 times over several months for a total of 10 or more cumulative population doublings in vitro . Electron microscopic studies revealed metabolically active cells with abundant melanosomes in various stages of melanization throughout the culture lifespan . Differences in size and number of melanosomes attributable to race of the tissue donor were readily apparent, and pigment content of melanocytes from both black and Caucasian donors appeared to increase with time in culture . Newborn melanocytes proliferated more rapidly and survived longer than did adult melanocytes, but there were no consistent morphologic differences as a function of donor age . Comparison of growth potential for the 3 major skin-derived cell types in this hormone-supplemented medium revealed striking specificity for melanocytes, with total elimination of keratinocytes over 1-2 weeks, and no fibroblast proliferation whatever in the absence of serum supplementation . This system promises to facilitate in vitro investigation of epidermal melanocytes in normal and diseased human skin. Int J Radiat Oncol Biol Phys, 1984 Nov, 10(11), 2125 - 30 Development of a rat lung cancer model; Byhardt RW et al.; A rat lung cancer model based on intrabronchial instillation of a tumor cell suspension has been developed for use in therapy and toxicity testing . Two tumors were used in this study, a sarcoma and an adenocarcinoma, both of which were of spontaneous origin in the strain of rats used . The inoculated tumor cells implant on the bronchiolar mucosa, forming a detectable single "primary" tumor resembling the spontaneous lung cancers arising in humans . The tumor growth is detectable by use of diagnostic radiographs, weight loss and other "clinical" signs . The tumors appear on chest radiographs 3 to 5 weeks after inoculation, and the implant rate is proportional to the number of tumor cells inoculated . Untreated animals have a median survival (after radiographic detection of the tumor) of 8 days, and die of local complications of tumor growth . When a slow growing transplantable tumor line of lung origin is developed, this model will be used to evaluate radiotherapy and chemotherapy schedules. Dev Biol, 1984 Nov, 106(1), 53 - 60 Two glial cell lineages diverge prenatally in rat optic nerve; Raff MC et al.; Three types of glial cells have been previously described in cultures of neonatal rat optic nerve--oligodendrocytes, type 1 astrocytes, and type 2 astrocytes--which can be distinguished using three different antibodies: antigalactocerebroside antibodies recognize oligodendrocytes; antibodies against glial fibrillary acidic protein recognize both types of astrocytes, while the A2B5 monoclonal antibody distinguishes between the two, binding to type 2 but not type 1 astrocytes . It was subsequently shown that oligodendrocytes and type 2 astrocytes, but not type 1 astrocytes, develop in cultures of 7 day optic nerve from a common, A2B5+ progenitor cell . In the present study, the distribution of rat neural antigen-2 (Ran-2), a cell-surface antigen defined by a monoclonal antibody, has been examined on optic nerve cells . It is demonstrated that, in contrast to A2B5, Ran-2 is present on type 1 but not type 2 astrocytes in optic nerve cultures . More importantly, it is shown that Ran-2 and A2B5 antibodies react with largely nonoverlapping populations of cells in cell suspensions of embryonic Day 17 (E17) and postnatal Day 1 (P1) optic nerve, and that the Ran-2+, A2B5- population contains type 1 astrocytes and their precursors while the A2B5+,Ran-2- population contains the progenitor cells for oligodendrocytes and type 2 astrocytes . These findings provide strong evidence that the glial cells of the rat optic nerve develop as two distinct lineages--one giving rise to type 1 astrocytes and the other to oligodendrocytes and type 2 astrocytes--and that the two lineages diverge as early as E17. Clin Immunol Immunopathol, 1984 Nov, 33(2), 191 - 8 The effect of NPT 15392, 9-(erythro-2-hydroxy-3-nonyl)-6-hydroxypurine, on the phytohemagglutinin of OKT3+, OKT4+, OKT8+, and OKM1+ cell-depleted and undepleted peripheral blood mononuclear cells; De Simone C et al.; NPT 15392, 9-(erythro-2-hydroxy-3-nonyl)-6-hydroxypurine, has been reported to influence immunological responses involving different cell types . Herein data are obtained by studying the influence of NPT 15392 on the phytohemagglutinin (PHA)-induced proliferative responses of unfractionated peripheral blood lymphocytes (PBLs) and of cell suspensions, which have been depleted of the cell subsets recognized by the monoclonal antibodies OKT3, OKT4, OKT8, and OKM1, in an attempt to identify which cell types respond to NPT 15392 in the PHA-driven blast transformation assay . The proliferative responses of unfractionated peripheral blood lymphocytes are potentiated when the drug is employed at the concentration of 0.1 microgram/ml and inhibited when NPT 15392 is added to the cell suspensions at concentrations over 5 micrograms/ml . The data reported here suggest that this phenomenon is a composite effect, made up of a combination of the counteracting effects caused by the OKT4+ cells on the one hand, and the OKT8+ and OKM1+ cells on the other. Clin Immunol Immunopathol, 1984 Nov, 33(2), 144 - 53 Natural killer (NK) cell activity in murine muscular dystrophy . II . Age-related tissue distribution and enhanced NK activity in the thymus of dystrophic mice; Semple JW et al.; The age-related tissue distribution of natural killer (NK) cell activity in murine muscular dystrophy was investigated . Lymphoid tissues including the spleen, thymus, mediastinal (or bronchial) lymph nodes (BLN), mesenteric lymph nodes (MLN), inguinal/popliteal lymph nodes (PLN1), and axillary/brachial lymph nodes (PLN2) were obtained from various aged normal (+/+) and dystrophic (dy2J/dy2J) C57BL/6J mice . Cell suspensions were incubated with 51Cr-labeled YAC-1 lymphoma target cells in a 4-hr 51Cr-release assay . The data indicated that dystrophic mice, at all ages studied, had elevated levels of NK activity in the spleen, BLN, MLN, PLN1, and PLN2 as compared with the normal age- and sex-matched control group . The NK activity in the thymocyte population from dystrophic mice at 2 weeks of age was found to be negligible, while at 8 weeks of age it was two-fold higher than that for the normal control group . In addition, dystrophic mice had an age-related decline in NK activity in all tissues after 10 weeks of age but the activity was still elevated at 40 weeks of age as compared with the normal control group . Target cell binding studies revealed that the number of conjugate-forming cells in thymocytes from 8-week-old dystrophic mice were found to be significantly higher than that found in normal mouse thymocytes using NK-sensitive YAC-1 tumor target cells . The number of cells bound per YAC-1 target cell ranged from 1 to 3 for dystrophic mouse thymocytes as compared with 1 to 2 for the normal control group . Thus, the data indicate an elevated NK activity in all lymphoid tissues studied from dystrophic mice of different ages . In addition, the thymus from dystrophic mice at 8 weeks of age contains an enhanced number of conjugate-forming NK cells and NK activity. Cancer Res, 1984 Nov, 44(11), 5369 - 75 Cytotoxicity of adriamycin in MGH-U1 cells grown as monolayer cultures, spheroids, and xenografts in immune-deprived mice; Erlichman C et al.; The cytotoxic activity of Adriamycin was examined in the MGH-U1 human bladder carcinoma line, grown as monolayer culture, as spheroids, and as xenografts in immune-deprived mice . The MGH-U1 cells grown as spheroids were much more resistant to Adriamycin (concentration of drug resulting in 37% cell survival, 4.5 micrograms/ml) than when treated as monolayer cultures (concentration of drug resulting in 37% cell survival, 0.9 microgram/ml) . Adriamycin fluorescence was demonstrated only in the outer two layers of cells forming the spheroids, suggesting that limited drug penetration is an important factor in the resistance of spheroids to Adriamycin . Sequential trypsinization of spheroids 750 micron in diameter allowed us to determine the cytotoxic effects of Adriamycin in MGH-U1 cells derived from different depths of the spheroid . We found that cells near the surface of the spheroid had a survival similar to those of exponentially growing monolayer cells treated with Adriamycin . Cells located in the middle of the viable rim were more resistant to Adriamycin, and those found near the necrotic center were most resistant to Adriamycin . The effects of Adriamycin treatment on spheroid growth delay were determined also . In spite of a small cytotoxic effect on the clonogenic fraction of cells in MGH-U1 spheroids, the growth delay effect of Adriamycin in intact spheroids was marked . This observation is consistent with Adriamycin killing primarily the cells in the outer layers of the spheroid, where most of the proliferation in the spheroid occurs . In vivo treatment of MGH-U1 xenografts with Adriamycin followed by assessment of cell survival in vitro showed minimal evidence of cytotoxicity, consistent with the poor drug penetration observed in the spheroid model . These studies suggest that: (a) Adriamycin penetrates poorly into solid tissues; (b) in vitro clonogenic survival following Adriamycin exposure of a cell suspension may predict falsely for drug sensitivity to chemotherapy; (c) a small decrease in clonogenic survival can be translated into a long growth delay but, ultimately, the tumor regrows because some clonogenic cells are spared; and (d) for Adriamycin, the spheroid model more closely parallels the in vivo effects than does monolayer culture . The use of the spheroid model for the study of Adriamycin cytotoxicity gives further insight into the action of this drug in solid tumors. J Pharmacol Exp Ther, 1984 Nov, 231(2), 441 - 8 Arachidonic acid metabolism in a cell suspension isolated from rabbit renal outer medulla; Ferreri NR et al.; We studied arachidonic acid (AA) metabolism by a cell suspension containing principally cells of the thick ascending limb of the loop of Henle (TALH) obtained from the inner stripe of the outer medulla of the rabbit kidney . Based on comparison of specific activities of enzymes before and after separation, alkaline phosphatase, Na+-K+-adenosine triphosphatase, as well as Tamm-Horsfall glycoprotein and electron microscopic appearance, 80% of these cells were estimated to be TALH in origin . TALH cells had low activity of cyclooxygenase and did not show evidence of lipoxygenase activity . However, they selectively converted exogenous AA to oxygenated metabolites by a cytochrome P-450 related mechanism . AA metabolites were produced in large amounts (30-40% conversion of {14C}AA, 1 to 5 micrograms/mg of protein/30 min) and were increased 5-fold after separation of TALH cells from a suspension of outer medullary cells, suggesting that TALH cells synthesized these metabolites . Induction of cytochrome P-450 by pretreatment of rabbits with beta-naphthoflavone and 3-methylcholanthrene increased formation of the AA metabolites by almost 2-fold in the separated cells and correlated with cytochrome P-450 content of the renal outer medulla . Additionally, SKF 525A and carbon monoxide inhibited product formation in these renomedullary cells, supporting a role for a cytochrome P-450-like monooxygenase in TALH cell function. Cell Tissue Kinet, 1984 Nov, 17(6), 593 - 600 Two-step cell-death kinetics in vitro during cis-platinum, hydroxyurea and mitomycin incubation; Bohmer RM; A human leukaemic cell line (REH) growing in suspension was incubated with cis-platinum, hydroxyurea and mitomycin C at various concentrations causing complete cell-cycle arrest . At different times the cell suspensions were harvested, diluted 1:1 with a buffer solution, stained without further treatment with a mixture of acridine orange (AO) and ethidium bromide (EB) and analysed with a biparametrical flow cytometer . Fluorescent plastic beads were introduced into the suspensions to provide an internal numerical reference for the control of cell loss . The fluorescence distributions showed three groups of cells: vital cells (V) which were only stained with AO; dead cells in which EB stained cytoplasmic components but not the nuclear DNA (D1), and dead cells which allowed EB to stain both cytoplasm and nuclear DNA (D2) . The kinetics of cells entering D1 depended on drug concentration and showed equal characteristics for cis-platinum and mitomycin, but were different for hydroxyurea . The subsequent entry into D2 occurred about 15 hr later and showed no pronounced dependence on drug concentration . Parallel trypan-blue (TB) exclusion tests revealed that TB only stained D2 cells and therefore is not useful for investigating cell-death kinetics during exposure to cell-killing agents. Semin Diagn Pathol, 1984 Nov, 1(4), 272 - 84 Immunohistology of lymphoproliferative disorders; Tubbs RR et al.; Malignant lymphomas have come to be recognized as neoplasms of the immune system . These lymphoproliferative disorders demonstrate surface and cytoplasmic antigenic phenotypes that reflect qualitative and quantitative alterations or aberrant expression of genetic material . Traditionally, cell suspension studies have been used for phenotypic analysis . Alternative immunohistologic methods can be used to profile immunophenotypes in situ . Most lymphoproliferative disorders can be readily classified as T or B cell malignancies, and criteria have been evolved to differentiate neoplastic from reactive/physiologic expansions of lymphoid clones . However, antigenic phenotypic expression does not always correspond to known immunophenotypes of subsets of T or B cells and probably reflects the complexity of neoplastic transformation . Currently, frozen tissue sections, preferably in combination with cell suspension analysis using cytocentrifuge preparations and/or flow cytometry, can provide information to phenotype lymphomas classified by the International Formulation or other nomenclature . Their continued utility depends on development of and adherence to strict quality assurance programs. Biochem J, 1984 Nov 1, 223(3), 723 - 31 The transient kinetics of uptake of galactosides into Escherichia coli; Page MG et al.; The uptake of galactosides into Escherichia coli via the lactose permease was studied in the time range 0.01-10s by rapid mixing and quenched flow . An initial transient was observed under two conditions . Firstly, a lag in the approach to the steady state was observed at low galactoside concentrations (less than Km) . Secondly, a burst of uptake was observed when anaerobic cell suspensions were mixed with aerobic substrate solutions . However, the cause of the burst of uptake appears to be a burst in the rate of respiration . The rate of galactoside uptake during this phase is 10-fold greater than during the steady state. Brain Res, 1984 Nov, 318(2), 203 - 17 Some immature tetanus toxin-positive cells share antigenic properties with subclasses of glial cells . An immunofluorescence study in the developing nervous system of the mouse using a new monoclonal antibody S1; Schnitzer J et al.; Monoclonal antibody S1 reacts in monolayer cultures with the cell surfaces of oligodendrocytes and a subclass of astrocytes derived from early postnatal mouse cerebellum, cerebrum and spinal cord, as well as with some glial cells in mouse retina but not in dorsal root ganglia . At earlier developmental stages S1 antigen is present in addition to oligodendrocytes and astrocytes on some tetanus toxin-positive neurons . S1 antigen is a developmentally early marker, detectable already in freshly trypsinized single cell suspensions from cerebella of 13-day-old embryos . Immunocytolysis of S1 antigen-bearing cells leads to reappearance of S1 positive glial cells but not tetanus toxin receptor-positive neurons . S1 antigen is also expressed in rat, rabbit, chicken and human . When cultured cells are permeabilized with denaturing agents, S1 antibody not only labels cell surfaces of some glial cells and, depending on the developmental stage, some neuronal cells but also intracellular components of all astrocytes, oligodendrocytes, neurons and fibroblasts. Lab Invest, 1984 Nov, 51(5), 504 - 14 Identification of two major B cell forms of nodular mixed lymphoma; Grogan TM et al.; To resolve the controversy over the immunologic nature of nodular mixed lymphoma (NM), we examined nine cases of NM for surface antigens using both tissue section and cell suspension methods . These were contrasted with 12 cases of nodular poorly differentiated lymphocytic lymphoma . We found two major B cell types of NM, those with monoclonal immunoglobulin (SIg+)-positive nodules with an SIg+B1+B2+Ia+T- phenotype (four cases) and those with nodules devoid of immunoglobulin with an SIg-B1+B2-Ia+T- phenotype (five cases) . Our SIg+ NM cases appear similar to nodular poorly differentiated lymphocytic lymphoma (SIg+B1+B2+Ia+T-), except suspension assay indicates fewer SIg+ cells in NM . In our SIg- NM cases, the neoplastic nodules consistently expressed B1 and Ia-like antigens and lacked T cells, indicating a B cell neoplasm similar to many large cell lymphomas . By demonstrating a B cell antigen in SIg- nodules, we substantially resolve the controversial NM cases previously called "null" or T cell . The two distinct immunotypes indicate the complexity of B cell antigenic expression in NM and might also explain the variable response to therapy in NM described in previous studies . Finally, we describe NM cases with the simultaneous occurrence of several stages of B cell differentiation . This suggests that some NM cases are not frozen in a single stage of B cell development but may express a range of B cell antigens . NM, then, may be a paradigm of variable, simultaneous B cell maturation. Exp Hematol, 1984 Nov, 12(10), 794 - 9 Effect of serum from mice treated with lipopolysaccharide on cycling of CFUs in vitro; Molendijk WJ et al.; Serum of lipopolysaccharide(LPS)-treated LPS-high-responder C3H/He mice was shown to increase survival of low-responder C3H/HeJ CFUs in an otherwise serum-free suspension culture by initiating cell cycling . Post-LPS serum of low-responder mice and serum of phosphate-buffered-saline-injected high-responder mice was significantly less effective in this respect . Since prolonged maintenance of CFUs was also found when cell suspensions highly enriched for stem cells were used, it seems unlikely that assessory cells mediated the effect of the post-LPS serum activity on CFUs maintenance . The serum activity did not enhance the stimulatory effect of saturating levels of highly purified stem-cell-activating factor (SAF) on CFUs maintenance in vitro . Upon injection of post-LPS serum from C3H/He mice a relatively small splenic CFUs accumulation in C3H/HeJ mice was observed. Am J Pathol, 1984 Nov, 117(2), 184 - 94 The immunohistology of the thymus in myasthenia gravis; Kornstein MJ et al.; We have investigated cell subpopulations in frozen sections of thymus tissue obtained from myasthenic (MG) and control subjects . With the use of an avidin-biotin immunoperoxidase system with monoclonal antibodies, the following cell surface antigens were studied on frozen sections (12 MG and 3 control thymus); T11, T4, T6, T8, IgM, IgD, and Ia . The pattern of T cell phenotypes in MG thymus is similar to that of normal control thymus when examined by immunohistologic techniques . MG cortical thymocytes are virtually all T11+, T4+, T8+, and T6+ . In the medulla, at least 45% of thymocytes are T11+, with T4+ cells predominating over T8+ cells . Approximately 10% of medullary thymocytes are T6+ . Scattered medullary cells expressing surface IgM and IgD are identified in both MG and normal thymuses . However, unlike the normal thymus, the MG thymus has numerous secondary follicles containing IgM- and IgD-bearing cells . This finding supports the hypothesis that the MG thymus microenvironment is aberrant . The Ia antigen is found in similar tissue section localization patterns in MG and control thymus . Ultramicroscopic studies show the Ia antigen predominantly on epithelial and interdigitating dendritic cells . By immunoperoxidase techniques, numerous keratin-positive cells are demonstrated in MG and control thymus . This suggests that thymic epithelial cells, like epithelial cells elsewhere, contain keratin . Because these data differ in degree from our previous findings in suspensions of MG thymocytes, this study emphasizes the importance of examining tissue sections as well as cell suspensions when one is studying lymphocyte surface markers. Res Commun Chem Pathol Pharmacol, 1984 Nov, 46(2), 187 - 205 Effect of calcium, sodium and isoproterenol on renin secretion from disaggregated rat renal cortical cells; O'Dea RF Jr et al.; A disaggregated cell system prepared from rat renal cortices has been developed to study the regulation of renin release in vitro . Cell suspensions were prepared by incubating minced renal cortical tissue in collagenase . The digested tissue was filtered sequentially through graded Teflon meshes of 125 and 44 mu, respectively . This preparation contained less than 2% intact glomeruli or tubules . Incubation of cell suspensions with the beta-adrenergic agonist L-isoproterenol (ISO) significantly increased the activity of renin released into the incubation media . Peak levels of renin activity were detected 10 to 15 min after the addition of ISO . The apparent ED50 for stimulation of renin release by ISO was 6 X 10(-8)M and the response was antagonized by the beta-adrenergic antagonist dl-propranolol . The spontaneous release of renin was also suppressed by increasing the concentration of extracellular calcium, whereas sodium ions had no effect on this process . These data have demonstrated that disaggregated renal cortical cell models are useful for studying the in vitro effects of pharmacologic agents and ions on renin secretion. Exp Cell Res, 1984 Nov, 155(1), 232 - 40 Ceruloplasmin receptors in liver cell suspensions are limited to the endothelium; Kataoka M et al.; The interaction of ceruloplasmin (CP) with isolated liver cell suspensions was studied using 125I-labeled and latex minibead-derivatized CP . Fractionation of liver cell suspensions was done using metrizamide gradient centrifugation . In crude liver cell suspensions only endothelial cells, but not hepatocytes and Kupffer cells bound the minibead probe . The binding was specific and inhibited by excess native CP . These results were confirmed using 125I-CP combined with cell fractionation technique . Kinetic data, obtained from the latter system, indicated a dissociation constant (Kd) of 1 X 10(-7) M and the number of receptors to be 5.7 X 10(5) per endothelial cell . The exclusive binding of CP to liver endothelium suggests that this cell may mediate the hepatocytes uptake of CP and is, therefore, a crucial element of the tissue-blood barrier. Proc Soc Exp Biol Med, 1984 Nov, 177(2), 278 - 82 Lymphoblastoid cell-induced suppression of human peripheral blood leukocyte mitogenic responses; Zhang JL et al.; Two lymphoblastoid tumor cell lines, the Burkitt lymphoma derived BJAB cell line which is free of Epstein-Barr virus (EBV) and B95-8 cells, which are marmoset lymphocytes transformed by EBV isolated from an infectious mononucleosis patient, were studied in regards to their effects on the blastogenic responsiveness of normal human peripheral blood leukocytes stimulated in vitro with mitogens . Mitomycin C treated tumor cell suspensions, when cocultured with normal human blood leukocytes, markedly depressed the expected blastogenic responses in vitro to concanavalin A, pokeweed mitogen, and phytohemagglutin . In addition, cell-free sonicates from the cell lines also depressed blastogenic responsiveness of the leukocytes in vitro . Heating the sonicates for 10 min at 100 degrees C markedly diminished the suppressive properties of the sonicates, as did ultraviolet light irradiation . The suppressive activity of the B95-8 sonicates was pelleted by high speed centrifugation as compared to the activity of sonicates derived from the BJAB cells . Further studies are warranted to determine the nature and mechanism of suppression of blastogenic responsiveness of normal human leukocytes by soluble components derived from such lymphoblastoid cell lines. Biochem Biophys Res Commun, 1984 Oct 30, 124(2), 393 - 9 Rapid polyphosphoinositide decrease is an early event in the steroidogenic response of bovine adrenocortical fasciculata cells to angiotensin II; Hadjian AJ et al.; Addition of angiotensin II (0.3 microM) to bovine adrenal fasciculata cell suspensions prelabeled with {32P} induced a rapid (15 seconds) and marked decrease of the radioactivity from phosphatidylinositol 4,5-biphosphate (62%) and phosphatidylinositol 4-monophosphate (35%) . This effect was concentration-dependent and specifically inhibited in the presence of (Sar1-Ala8)-angiotensin II; it was also completely prevented in the absence of extracellular calcium . The present data appear to illustrate the earliest biological response detectable in bovine fasciculata cells under angiotensin II challenge. J Biol Chem, 1984 Oct 25, 259(20), 12619 - 27 Morphological and physiological factors affecting oxygen uptake and release by red blood cells; Vandegriff KD et al.; The kinetics of oxygen uptake and release by human, salamander (Amphiuma means), and artificially constructed red cells were measured under a variety of physiological conditions using stopped-flow, rapid mixing techniques . The results were analyzed quantitatively using the generalized, three-dimensional disc model that was developed in two previous publications (Vandegriff, K . D., and Olson, J . S . (1984) Biophys . J . 45, 825-835 and Vandegriff, K . D., and Olson, J . S . (1984) J . Biol . Chem . 259, 12609-12618) . The apparent rate of gas exchange is governed primarily by the oxygen flux at the red cell surface . In the case of uptake, this flux is roughly independent of intracellular chemical reaction parameters and inversely proportional to the thickness of the unstirred solvent layer which is adjacent to the red cell surface . For release experiments in the presence of high concentrations of sodium dithionite, the flux at the cell surface is inversely proportional to the oxygen affinity of the intracellular hemoglobin and roughly independent of the thickness of the external unstirred solvent layer . As a result, the effects of cell size, internal heme concentration, and pH are expressed differently in the two types of kinetic experiments . The rate of oxygen uptake depends on roughly the second power of the surface area to volume ratio of the erythrocyte, whereas the rate of release is much less dependent on the size and shape of the red cell . The half-time of oxygen uptake is directly proportional to intracellular heme concentration for cells of equivalent geometries; the half-time of oxygen release is linearly dependent on internal heme concentration but, at low heme concentrations, is determined primarily by the rate of oxygen dissociation from hemoglobin . The rate of cellular oxygenation is roughly independent of pH and internal 2,3-diphosphoglycerate concentration; in contrast, the rate of deoxygenation depends markedly on these conditions . As the pH is lowered or the internal diphosphoglycerate concentration is raised, the overall oxygen affinity of the cell suspension decreases severalfold, and the rate of oxygen release increases by roughly the same extent. FEBS Lett, 1984 Oct 15, 176(1), 55 - 60 Pyrimidine metabolism in Trichomonas vaginalis; Heyworth PG et al.; Pyrimidine metabolism in Trichomonas vaginalis was investigated using washed cell suspensions of the organism with radiolabelled pyrimidine ring precursors and preformed pyrimidines . The precursors {14C}orotate, {14C}bicarbonate and {14C}aspartate were not incorporated into the pyrimidine bases of trichomonal nucleic acids, indicating that the protozoan is unable to synthesise the pyrimidine ring and is dependent on the salvage of exogenous pyrimidines . {3H}uracil, {3H}uridine, {3H}cytidine, deoxy{3H}cytidine and {3H}thymidine were all efficiently salvaged, and interconversion between cytosine and uracil nucleotides was detected . Thymidylate synthase activity was not detected, suggesting that T . vaginalis is dependent upon an exogenous supply of thymidine for TMP synthesis. Cell Immunol, 1984 Oct 15, 88(2), 401 - 10 Separation of spleen colony-forming units and prothymocytes by use of a monoclonal antibody detecting an H-2K determinant; Mulder AH et al.; The density of H-2K antigens was determined on both the mouse hemopoietic stem cell, using an assay for spleen colony-forming units (CFU-S), and the prothymocyte, using a thymus repopulation assay . This was done by light-activated cell sorting of bone marrow cells labeled first with a biotinylated antibody against H-2Kk and then with avidin-fluorescein isothiocyanate . Almost all CFU-S were found to be present among the 4% bone marrow cells with high forward light scatter (FLS), low perpendicular light scatter (PLS), and bright immunofluorescence . Thymus regeneration by this brightly fluorescent fraction was delayed 3 days compared to thymus regeneration by unsorted cells, although the same number of CFU-S was present in each cell suspension . This delay indicates that differentiation from CFU-S to prothymocytes takes 3 days . The fraction of cells in the FLS/PLS window with dull anti-H-2Kk fluorescence contained few CFU-S and gave rise to a transient thymus regeneration . These findings indicate that the prothymocyte carries fewer H-2K antigens than does the CFU-S . The H-2K antigen is a marker with which CFU-S and prothymocytes can be separated . Therefore, during early T-cell differentiation, the number of H-2K molecules on the cell surface decreases (CFU-S----prothymocyte----cortical thymocyte) . During maturation of T cells, a reexpression of H-2K molecules occurs, since lymph node cells and spleen cells were shown to be brightly positive for H-2K antigen. Tsitologiia, 1984 Oct, 26(10), 1203 - 8 {Sedimentation analysis of cell suspensions}; Doronin IuK; Simple methods of measurements of the velocity sedimentation at unit gravity of cells obtained by disaggregation procedure from some fixed tissues are described . The relationship between the velocity sedimentation and cellular volume is discussed. Eur J Cancer Clin Oncol, 1984 Oct, 20(10), 1249 - 59 Flow cytofluorometric analysis of serial biopsies of tumours of the uterine cervix; Dyson JE et al.; The technique of flow cytofluorometry has been employed to assess, by means of cell suspensions prepared from serial biopsies, the radioresponsiveness of tumours of the uterine cervix . This enables DNA profiles and content of proliferating cells to be determined prior to treatment and during external beam and intracavitary therapy . Results show that elimination of hyperdiploid and hypertetraploid cells and reduction in the proliferating fraction of cells can readily be monitored by this method during therapy . This information, quickly available during treatment, may assist in estimating radioresponsiveness of the tumour and possible prognosis for the patient . Dose fractionation schedules may also be adjusted according to tumour response to therapy . Our results, however, show no relationship between histopathological classification of a tumour (WHO) and its ploidy state . The advanced stages of the disease (II and III) do, however, show an increased content of hypertetraploid cells in the tumour biopsies. Radiologe, 1984 Oct, 24(10), 478 - 87 {Hemorheologic effects of ioxaglate: a contribution to an interpretation of the effect of hyperosmolar roentgen contrast media on the fluidity of erythrocytes}; Schmid-Schonbein H et al.; Almen and Aspelin have shown that the use of non-ionic radio contrast media allows the iodine concentration to be increased (which is desirable because of its effect on radio opacity) without a very large increase in osmolarity (which is undesirable because it impairs the fluidity of erythrocytes) . This latter effect can also be diminished by reducing the osmolarity of a dimeric contrast medium as has been achieved by incorporating more iodine atoms into the molecule in the case of Ioxaglate (Hexabrix) . In various microrheological tests systems, the fluidity of packed red cell suspension, the corrected filtration rate though 5 micron pores and the relative apparent viscosity of blood-contrast media mixtures (1 to 50% concentration) were determined in experiments comparing this compound with Urografin 76 of the same iodine content . In all systems, the former showed fewer rheological effects . In whole blood viscometry, this can be detected only after appropriate corrections for the effects of the two contrast media on hematocrit and plasma viscosity . As there is a more pronounced water shift from the cells to the plasma, Urografin tends to reduce the viscosity of the plasma-contrast media mixture . The concomitant reduction in MCV and hematocrit level tends to conceal the macrorheological influence of strong cell stiffening . This microrheological effect of the dehydrated cells becomes immediately obvious when the viscometric data are corrected for hematocrit value and plasma viscosity effects. J Embryol Exp Morphol, 1984 Oct, 83, 43 - 61 Intercellular relationships during cavitation of aggregates of extraembryonic endoderm cells from gastrulating chick embryos; Milos N et al.; Extraembryonic endoderm cells from gastrulating chick embryos undergo epiboly and change from a multilayered cell group to a single cell layer surrounding the yolk . Single cell suspensions from this cell layer can aggregate in vitro to form aggregates that cavitate . To study the stages of cavitation aggregates were harvested after different times in culture, and fixed and processed for light and electron microscopy . In aggregates harvested at 75 min of culture cell contact consisted of areas of parallel and close membrane apposition and interdigitation . Desmosomes were occasionally observed . Aggregates in the early stages of cavitation (24 h) contained numerous intercellular spaces bordered by irregularly shaped cells which appeared to be digesting their yolk and releasing material extracellularly . Long cytoplasmic projections were extended into these spaces . In addition to regions of parallel membrane apposition and interdigitation, desmosomes and adherens junctions were observed . Cells closer to the periphery of the aggregates displayed fewer cell projections and also showed signs of release of material extracellularly . After 48 h of culture, a single smooth-walled central cavity was present and cells still exhibited signs of extracellular release of material . These same cell shapes and intercellular junctions were also observed when area opaca tissue dissected from gastrulating embryos was examined . Aggregates of different sizes were created and cultured . The results suggest that a critical tissue mass may be important for cavitation. Transplantation, 1984 Oct, 38(4), 392 - 5 Minor antigen graft-versus-host reactions revealed in irradiated spleen and popliteal lymph node assays; Claman HN et al.; The graft-versus-hot (GVH) reaction across minor (non-H-2) histocompatibility barriers was studied in mice, in vivo . To increase GVH potential and to mimic clinical bone marrow transplantation protocols, we modified the popliteal lymph node (PLN) and the splenomegaly assays by irradiating the recipients before they received allogeneic lymphoid cell suspensions . In several combinations across major (H-2), minor (non-H-2) and multiple minor (non-H-2 plus minor lymphocyte stimulation) barriers, increased recipient organ weight (a measure of GVH activity) was seen with irradiated F1 recipients of parental cells . The irradiated splenomegaly (x-splenomegaly) assay was more sensitive than the (x-PLN) assay, but both correlated with in vivo GVH experiments of the P----F1 variety . The x-splenomegaly test indicated histoincompatibility in a system (B10.D2----BALB/c) in which the primary in vitro mixed leukocyte reactions is nonreactive, but in which systemic GVH can be induced . The x-splenomegaly test should be useful in analyzing complex reactions involving minor histocompatibility antigens in vivo. J Neurosurg, 1984 Oct, 61(4), 761 - 6 Intramedullary canine spinal cord tumor model; Salcman M et al.; The development of a transplantable model brain tumor in the neonatal dog, the adaptation of the tumor to tissue culture, and the successful growth of the tumor in adult mongrel dogs has been adapted to producing similar tumors in the thoracic spinal cord of the adult dog . Ten adult dogs, weighing 4 to 25.4 kg each, were subjected to formal laminectomy . The tumor cell suspension was injected by hand with a Hamilton syringe at two or three sites over a distance of 1 cm; each site received an injection volume to 0.02 to 0.05 cc of the cell suspension after the dura had been opened . Immediately after injection the field was copiously irrigated and the puncture area sealed with a single drop of ethyl cyanoacrylate . Tumor cells for injection were obtained by thawing ampules stored at -195 degrees C in a mixture of 10% dimethyl sulfoxide and RPMI 1640 culture medium . Cells were resuspended in Hank's balanced salt solution and 15% fetal calf serum on ice . Solutions had 90% cell viability, and animals received a dose in the range of 3 to 13 X 10(6) cells . Eight animals developed tumors and became paraparetic on the 9th to 14th postinjection day . Metrizamide myelography in three animals revealed complete blocks; two animals underwent spinal computerized tomography (CT) and demonstrated syringohydromyelia . Histology revealed the tumors to be highly vascular primitive neoplasms that invaded the surrounding cord . This spinal cord tumor model is large enough to be operated on, studied by CT and myelography, and subjected to pharmacological, electrophysiological, and blood flow study. J Infect Dis, 1984 Oct, 150(4), 508 - 12 Comparison of strains of Legionella pneumophila serogroup 1 isolated in four Amsterdam hospitals from patients and hot-water supplies; Zanen-Lim OG et al.; Legionella pneumophila serogroup 1 was isolated from patients (14 strains) and hot-water taps (49 strains) in four hospitals in Amsterdam . Precipitation patterns obtained by reaction of heated cell suspensions and rabbit antisera in the double diffusion test revealed antigenic properties of serogroup 1 strains from water unique to each of the four hospitals . By this method similarity could be demonstrated between strains from patients and hot water in three of the four hospitals . No such relationship was present in the fourth hospital, a fact that could be explained by the case histories of the patients . Comparison of strain antigens in the double diffusion test is simple and suitable for epidemiological studies of L . pneumophila. Endocrinology, 1984 Oct, 115(4), 1406 - 11 Preparation of thyrotroph cells from adult male rat pituitary glands by centrifugal elutriation; Chamras H et al.; To study the metabolism of thyrotrophs and dynamics of TSH secretion in vitro, it is desirable to have a highly enriched population of thyrotrophs . For that purpose, centrifugal elutriation, a recently developed cell isolation method based on the size and density of cells, was used to prepare thyrotrophs from a cell suspension of adult male rat pituitary cells . Trypsin-dispersed cells (4-8 X 10(7} were loaded into the elutriation rotor (Beckman, JE-6) operating at 2800 rpm . Twelve cell fractions were collected at variable rotor speed (2000-2800 rpm) and increasing medium flow rate (10-103 ml/min) . Cell recovery was 77-98% . The viability of the cells after elutriation was 90-95% based on trypan blue exclusion . Each fraction was analyzed for TSH, GH, and PRL content and for TRH-stimulated TSH release by RIA . Thyrotrophs were found predominantly in fractions 8-11 (flow rate 38-75 ml/min) based on TSH RIA . The mean TSH concentration in these fractions was 56 +/- 13.6 (+/- SD) microU/10(3) cells compared with 7.6 +/- 3.8 microU/10(3) cells in the initial cell suspension, representing a 7- to 8-fold enrichment of the thyrotrophs . Incubation with 20 nM TRH for 3 h increased the TSH release of cells eluted in fractions 8-11 by 3- to 5-fold; there was no significant increase in TSH release in fractions 3-6 . Centrifugal elutriation may be used to prepare a uniform highly enriched thyrotroph fraction with excellent recovery from a suspension of rat pituitary cells . This technique should be valuable for study of the metabolism of thyrotrophs. Int J Radiat Oncol Biol Phys, 1984 Oct, 10(10), 1913 - 22 Characterization of the biophysical properties of human tumor and bone marrow cells as a preliminary step to the use of centrifugal elutriation in autologous bone marrow transplantation; Keng PC et al.; The principle of centrifugal elutriation (CE) depends on a balance of an outwardly directed centrifugal force and inwardly directed fluid flow and buoyant forces . This method (CE) can be used effectively to separate cells on the basis of size . In the murine model, neoplastic cells from different tumors are generally larger than bone marrow cells and can be removed from bone marrow almost completely with centrifugal elutriation . In order to determine if CE is capable of eliminating human tumor cells from harvested bone marrow (BM), the biophysical characteristics of a variety of human tumor cells and bone marrow cells were determined . Human tumor cells were dispersed into single cell suspensions by several enzymatic digestion and mechanical dissociation methods . The size and density characteristics of these cells were determined with an electronic particle counter and channelyzer and density gradients . Of 40 solid tumors studied, 29 tumors had cell size distributions distinctively larger than BM, as was found in the experimental animal model . The cell size distributions of tumor cells from 11 solid tumors and 7 leukemias were not substantially different from that of BM . Mixtures of BM and cultured human hypernephroma, ovarian, and neuroblastoma cells, were separated into BM and tumor fractions by CE . The separation results as indicated by the labeling index and colony forming efficiency of tumor cells in each fraction showed that a BM fraction virtually free of tumor cells could be obtained . Thus, CE should be able to separate BM cells from most tumor cells metastatic to BM. Am Rev Respir Dis, 1984 Oct, 130(4), 650 - 8 Accurate quantification of cells recovered by bronchoalveolar lavage; Saltini C et al.; Quantification of the differential cell count and total number of cells recovered from the lower respiratory tract by bronchoalveolar lavage is a valuable technique for evaluating the alveolitis of patients with inflammatory disorders of the lower respiratory tract . The most commonly used technique for the evaluation of cells recovered by lavage has been to concentrate cells by centrifugation and then to determine total cell number using a hemocytometer and differential cell count from a Wright-Glemsa-stained cytocentrifuge preparation . However, we have noted that the percentage of small cells present in the original cell suspension recovered by lavage is greater than the percentage of lymphocytes identified on cytocentrifuge preparations . Therefore, we developed procedures for determining differential cell counts on lavage cells collected on Millipore filters and stained with hematoxylin-eosin (filter preparations) and compared the results of differential cell counts performed on filter preparations with those obtained using cytocentrifuge preparations . When cells recovered by lavage were collected on filter preparations, accurate differential cell counts were obtained, as confirmed by performing differential cell counts on cell mixtures of known composition, and by comparing differential cell counts obtained using filter preparations stained with hematoxylin-eosin with those obtained using filter preparations stained with a peroxidase cytochemical stain . The morphology of cells displayed on filter preparations was excellent, and interobserver variability in quantitating cell types recovered by lavage was less than 3%.(ABSTRACT TRUNCATED AT 250 WORDS) Blood, 1984 Oct, 64(4), 768 - 73 Studies of lymph nodes from patients with classical hemophilia; Andes WA et al.; Within the last 18 months, we have noted the development of unexplained lymph node enlargement in otherwise asymptomatic patients with hemophilia . Because such changes are poorly understood and, in some patient groups, may be related to the acquired immunodeficiency syndrome (AIDS), we studied the enlarged lymph nodes in four patients with severe factor VIII deficiency and abnormally low peripheral blood helper-inducer/suppressor cell (OKT4/OKT8) ratios . Surgically excised lymph nodes were studied for histopathologic, electron microscopic, and chromosomal changes . Cell suspensions from these and normal nodes were also studied using monoclonal antibodies . Excised lymph nodes showed follicular hyperplasia . Electron microscopy revealed no viral particles or vesicular rosettes . Chromosomal aberrations included an acrocentric marker chromosome in one patient and monosomy 21 in another . T lymphocyte ratios (OKT4/OKT8) in lymph node suspensions were lower than those in nodes from normal controls (1.2 v 6.1) and reflected the lymphocyte ratio in peripheral blood . Mature B cell percentages were increased in the lymph nodes from patients with hemophilia (38% v 27% in controls) . Patients treated with factor VIII concentrates and male homosexuals have similarities in persistent lymph node enlargement, histologic features of follicular hyperplasia, and changes in lymph node and circulating lymphocyte subpopulations. J Virol, 1984 Oct, 52(1), 290 - 2 Monoclonal antibodies to a monkeypox virus polypeptide determinant; Roumillat LF et al.; Three monkeypox virus (MPV) antibody-secreting murine monoclones were characterized as being of the immunoglobulin G1 isotype, gave a 4+ reaction in the indirect fluorescent-antibody test, gave a positive reaction in the enzyme immunoassay, and did not neutralize MPV . These monoclonal antibodies were determined by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis transblot method to react to a 15,500-molecular-weight MPV polypeptide . This reactivity could not be removed by adsorption to a vaccinia virus-infected cell suspension . The three monoclonal antibodies were specific for MPV when tested against epidemiologically unrelated isolates of cowpox virus, variola virus, vaccinia virus, and MPV. J Histochem Cytochem, 1984 Oct, 32(10), 1028 - 34 Immunocytochemical assays of amylase and chymotrypsinogen in rat pancreas secretory granules . Efficacy of using immunogold-labeled ultrathin cryosections to estimate relative protein concentrations; Posthuma G et al.; An exploration was conducted as to whether the relative concentration of two intracellular proteins could be evaluated quantitatively from their labeling densities in ultrathin cryosections labeled with the immunogold technique . As a model rat pancreatic cells were used in which the content of amylase (Am) and chymotrypsinogen (Ch) was experimentally altered . Rats were fed either normal laboratory chow or food containing soybean trypsin inhibitor (STI), which affects the Am/Ch ratio in the tissues . The changes in Am and Ch protein levels and enzyme activities were measured biochemically in cell suspension homogenates or in zymogen granule fractions . Within 5 days a maximal change in the Am/Ch was observed as a result of adaptation to the STI diet . The Am/Ch ratio determined biochemically was compared with that from counts of gold particles bound to the respective protein in immunogold-labeled cryosections . The two data sets matched fairly well, indicating that the intensity of the immunoreaction is a reliable reflection of antigen concentration in this system. Am J Clin Pathol, 1984 Oct, 82(4), 439 - 41 Use of a modified procedure for treating small amounts of red blood cells with 2-aminoethylisothiouronium bromide; Ellisor SS et al.; Kell null red blood cell samples can be prepared using 2-aminoethylisothiouronium bromide (AET) . This article describes a modification whereby only three drops of a 5% red blood cell suspension may be AET treated . This procedure has been used routinely in the authors' laboratory for more than a year . One patient's serum contained anti-Kpb plus anti-C and anti-D . Tests with panel cells pretreated with AET made it possible to identify underlying Rh antibodies without using a panel of genetic Kpb negative red blood cells . Of 24 red blood cell eluates from patient sample with warm autoantibodies, one had specificity within the Kell blood group system . This small volume AET-treatment method is a quick screen for the differentiation of a Kell-related specificity from a non-Kell specificity of both warm autoantibodies and alloantibodies to high-incidence antigens. Carcinogenesis, 1984 Oct, 5(10), 1267 - 75 Emergence of a population of small, diploid hepatocytes during hepatocarcinogenesis; Schwarze PE et al.; The sequential treatment of young Wistar rats with two different carcinogens (diethylnitrosamine - plus partial hepatectomy - as an initiator, and 2-acetylaminofluorene as a cytotoxic selection pressure) induces the appearance of foci and nodules of liver cells which are phenotypically altered . By means of an algorithm which takes into account binuclearity as well as cell-to-cell aggregation it is possible to compute cellular ploidy distributions from flow-cytometric analysis of either hepatocyte suspensions or suspensions of hepatocytic nuclei . Cell suspensions isolated from carcinogen-treated rats can be shown to contain, already after 8 weeks, approximately 70% small, diploid hepatocytes, whereas suspensions from normal or partially hepatectomized control livers contain only approximately 10% diploid cells (the remainder being mostly tetraploid) . Isolated nodules, i.e., expanding clones of proliferating cells, believed to be neoplastic precursor lesions, contained almost only diploid cells . These observations suggest that the selective outgrowth of a population of small, diploid hepatocytes may be a significant early step in the development of liver cancer. Proc Natl Sci Counc Repub China B, 1984 Oct, 8(4), 275 - 81 An improved dispersed adrenal cell assay for corticotropin in rat plasma; Lin JH et al.; The present study was designed to improve the dispersed adrenal cell technique for determining adrenocorticotrophic hormone (ACTH) concentrations in small amounts of rat plasma . Priming with ACTH, incubation with methyl-isobutylxanthine, or dexamethasone pre-treatment were employed as modifications . Of these, only dexamethasone pre-treatment increased the sensitivity of the assay . The adrenal fragments obtained from 10-12 adult male rats pre-treated with dexamethasone (100 micrograms/kg B.W.) one hour before sacrifice, were digested with collagenase and deoxyribonuclease solution for 30 minutes . The dispersed cells were collected by centrifugation and resuspended in Krebs-Ringer bicarbonate buffer containing 0.2% glucose and 0.5% bovine serum albumin . Aliquots of cell suspension (3-4 X 10(4)/tube) were incubated with various doses of ACTH1-24 or the eluate of plasma samples at 37 degrees C for 2 hours in an atmosphere of 95% O2/5% CO2 in a Dubnoff shaker . The quantity of corticosterone produced was measured fluorimetrically . The assay is precise (lambda = 0.06), extremely sensitive (10 fg/tube), and convenient . One skilled technician can handle 15 to 20 plasma samples per day using 10 rats as the source of assay cells . ACTH can be measured in as little as 10-50 microliters of eluate. Biochim Biophys Acta, 1984 Sep 19, 776(1), 1 - 9 K+-valinomycin and chloride conductance of the human red cell membrane . Influence of the membrane protonophore carbonylcyanide m-chlorophenylhydrazone; Bennekou P; Chloride ion conductance of the human red cell membrane has been calculated, as the ratio between ion net charge flux and driving potential . The proton carrier CCCP was used to monitor changes in membrane potential following addition of valinomycin in sufficient quantities to raise the K+ conductance to a level comparable to the Cl- conductance . A K+-specific electrode was used to monitor changes in extracellular K+ concentration, and an H+-sensitive glass electrode for changes in extracellular pH, reflecting changes in membrane potential . The effects of varied concentrations of valinomycin and CCCP upon K+ and Cl- conductances were studied . It was found that, within an experimental error of about 10% S.D., the chloride conductance was constant for valinomycin concentrations in the range 1.0 X 10(-8)-1.0 X 10(-6), and for CCCP-concentrations in the range 2.0 X 10(-7)-2.0 X 10(-5) mol per litre cell suspension, while at a constant concentration of valinomycin the induced K+ conductance was considerably augmented by addition of CCCP. Dtsch Med Wochenschr, 1984 Sep 7, 109(36), 1356 - 61 {Clinical significance of the short-term incubation test for the therapy of metastatic breast cancer}; von Matthiessen H et al.; Between January 1978 and October 1980 97 tissue samples of histologically verified carcinoma of the breast were received for performance of the short-term incubation test . 25 tumour samples could not be prepared as cell suspension sufficient for testing . Among the 72 performed tests there were 9 with stimulation of 3H-uridine uptake by doxorubicin . Thus only 63 tests could be evaluated . Results were correlated with clinical data of the patients . No significant correlations could be established between tumour stage at time of diagnosis, age, menopausal state, receptor state, and the test result . There was also no differentiation between favourable and unfavourable prognoses as regards free interval and rate of survival . A correlation between results of tests and success or failure of cytostatic treatment could not be ascertained. J Bacteriol, 1984 Sep, 159(3), 843 - 9 Physiological function of hydrogen metabolism during growth of sulfidogenic bacteria on organic substrates; Lupton FS et al.; Desulfovibrio vulgaris Madison and Thermodesulfobacterium commune contained functionally distinct hydrogenase activities, one which exchanged 3H2 into 3H2O and was inhibited by carbon monoxide and a second activity which produced H2 in the presence of CO . Cell suspensions of D . vulgaris used either lactate, pyruvate, or CO as the electron donor for H2 production in the absence of sulfate . Both sulfidogenic species produced and consumed hydrogen as a trace gas during growth on lactate or pyruvate as electron donors and on thiosulfate or sulfate as electron acceptors . Higher initial levels of hydrogen were detected during growth on lactate-sulfate than on pyruvate-sulfate . D . vulgaris but not T . commune also produced and then consumed CO during growth on organic electron donors and sulfate or thiosulfate . High partial pressures of exogenous H2 inhibited growth and substrate consumption when D . vulgaris was cultured on pyruvate alone but not when it was metabolizing pyruvate plus sulfate or lactate plus sulfate . The data are discussed in relation to supporting two different models for the physiological function of H2 metabolism during growth of sulfidogenic bacteria on organic electron donors plus sulfate . A trace H2 transformation model is proposed for control of redox processes during growth on either pyruvate or lactate plus sulfate, and an obligate H2 cycling model is proposed for chemiosmotic energy coupling during growth on CO plus sulfate. Br J Surg, 1984 Sep, 71(9), 659 - 63 Viability of exfoliated colorectal carcinoma cells; Umpleby HC et al.; The viability of tumour cells shed into the intestinal lumen was determined in 49 patients with carcinoma of the large bowel . Preoperative colorectal lavage was performed in 19 patients and irrigation of the cut ends of the operative specimen in 30 patients . The resulting cell suspensions were centrifuged on a Nycodenz linear density gradient column so that tumour cells, being larger, were concentrated in a band at the top . In 14 of 19 colorectal lavage cases viable tumour cells were recovered, as assessed by their characteristic morphology and ability to exclude trypan blue . A median of 0.78 X 10(6) viable tumour cells was recovered . The median percentage cell viability in the suspension was 92, i.e . 8 per cent of the tumour cells were dead (stained with trypan blue) . In eight specimens viability was confirmed by the ability of tumour cells to hydrolyse fluorescein diacetate . In 17 of 30 proximal resection margin irrigations a median of 0.55 X 10(5) viable tumour cells was recovered, with a median percentage viability of 92.5 . In 15 specimens the neoplastic cells showed fluorescence . In 21 of 25 distal resection margin irrigations a median of 1.92 X 10(5) viable tumour cells was recovered with a median percentage cell viability of 79.3, and fluorescence was observed in all specimens . The number of viable tumour cells did not correlate with the stage, differentiation, diameter or fixity of the tumour . However, the number of tumour cells recovered from the distal resection margin was inversely related to the distance of the tumour from that margin (Rank Difference Coefficient R = -0.6) . Thus viable exfoliated tumour cells were demonstrated in 52 of 74 specimens (70 per cent) . Their presence in large numbers at the site of intestinal anastomoses supports a potential role in the aetiology of suture-line recurrence. J Cell Biol, 1984 Sep, 99(3), 1173 - 8 Expression of cone-like properties by chick embryo neural retina cells in glial-free monolayer cultures; Adler R et al.; We report here that cells present in embryonic chick retinal monolayer cultures express differentiated properties characteristic of chick cones developing in vivo . Cell suspensions from 8-d chick embryo retina (a stage when photoreceptor differentiation has not yet started) were cultured for up to 7 d in low density, glial-free monolayers . Under these conditions, monopolar cells represent approximately 40% of the total number of process-bearing neurons . After 6 d in vitro, most of these monopolar cells showed morphological features reminiscent of developing chick cones . These features could be detected with phase-contrast microscopy, lectin cytochemistry, and transmission and scanning electron microscopy . Characteristic cone traits expressed by cultured monopolar cells included the following: (a) a highly polarized organization; (b) a single, short, usually unbranched neurite; (c) the polarized position of the nucleus close to the origin of the neurite; (d) characteristic cone inner segment features such as abundant free ribosomes, a polarized Golgi apparatus, a cluster of mitochondria distal to the nucleus, a big, membrane-bound, pigment-containing vacuole reminiscent of the "lipid droplet" characteristic of chick cones, and at least in some cases, a well-developed paraboloid; (e) the presence of a complex of apical differentiations including abundant microvilli and in some cases also a cilium-like process; and (f) the staining of the apical region of the cell with peanut lectin, which has been shown to be selective for chick embryo cones (Blanks, J.C., and L.V . Johnson, 1983, J . Comp . Neurol., 221:31-41; and Blanks, J.C., and L.V . Johnson, 1984, Invest . Ophthalmol . Visual Sci., 25:546-557) . This pattern of differentiation achieved by 8-d chick retina cells after 6 d in vitro is similar to that shown by 14-d-old chick embryo cones in vivo . Outer segments are not present at this stage of development either in vivo or in vitro . This experimental system is now being used to search for cellular and molecular signals controlling survival and differentiation of cone cells. Cell Immunol, 1984 Sep, 87(2), 674 - 7 Natural killer activity of Kurloff cells: a direct demonstration on purified Kurloff cell suspensions; Debout C et al.; In order to study their natural killer effect, guinea pig splenic Kurloff cells were fractionated by Percoll discontinuous density gradient centrifugation . Kurloff cells were collected and tested for cytotoxicity in a 24-hr chromium-release test . Comparison of different splenic cellular samples (of males or estrogenized females) with increasing percentage of Kurloff cells, revealed a highly significant positive correlation (r = 0.93, alpha less than 0.01) with the cellular cytotoxicity developed against the K 562 target cells. Blood, 1984 Sep, 64(3), 649 - 55 Light scattering by polymorphonuclear leukocytes stimulated to aggregate under various pharmacologic conditions; Yuli I et al.; Enhancement of light transmission has been widely accepted as an empirical measure of cell aggregation in suspension . Several years ago, this measurement was introduced to the study of polymorphonuclear leukocyte (PMN) aggregation by adapting a hypothesis originally developed for platelets . Accordingly, an increase in light transmission is attributed to cell aggregation and a decrease in transmission below baseline level is indicative of increased cell symmetry . We tested this hypothesis for human PMNs by comparing the whole cell shape or the cells' aggregation state with the light transmission under particular experimental conditions . The PMN light response to the chemoattractant, f-Met-Leu-Phe, in the presence of low doses of aliphatic alcohols was associated with transient enhanced transmission, followed by a rapid decrease below baseline . In contrast to the platelet hypothesis, the below-baseline effect coincided with a decrease in PMN symmetry from spheres to wedge-shaped (polarized) cells . PMNs fixed mildly with various doses of formaldehyde (0.1% to 0.3%) were completely aggregated by the addition of 50 micrograms/mL phytohemagglutinin (PHA) . Despite the complete aggregation of the PMNs, there was a dose-dependent inhibition of the above-baseline level transmission response by the fixative, demonstrating a clear dichotomy between aggregation and increased light transmission . However, PMN aggregation could be monitored by observing the pattern of enhanced light transmission coupled with decreased perpendicular light scattering immediately after the stirring of the cell suspensions was stopped . PMNs aggregated by PHA cleared from suspension very rapidly (t1/2 less than or equal to one minute), whether or not they were formalin-fixed . In contrast, unaggregated cells revealed constant transmission and perpendicular scattering intensities for as long as five minutes after the stirring was stopped . The clearance patterns of f-Met-Leu-Phe-stimulated PMNs initiated even at the time of maximally increased light transmission were indistinguishable from those of the unstimulated cells, indicating the absence of aggregation . The lack of correlation between light output and changes in cell shape or degree of aggregation of PMNs causes us to reject the hypothesis that attributes enhanced light transmission to PMN aggregation . We suggest that modulation of light transmission by PMNs stimulated with chemoattractants is due to changes in light output from subcellular objects. Cancer Res, 1984 Sep, 44(9), 3870 - 2 Lymphokine-induced migration inhibition of murine tumor cells derived from solid neoplasms; Donskoy M et al.; We have previously described a noncytotoxic lymphokine, tumor migration inhibition factor, with the capacity of inhibiting the in vitro migration of a variety of tumor cells maintained by animal passage in ascitic form . In the present study, we demonstrate that it is possible to prepare viable, motile tumor cell suspensions from solid tumors and that those cells migrate better than cells that had been propagated in ascitic form . Such preparations derived from solid tumors are inhibited by tumor migration inhibition factor to a degree comparable to that achieved with cells from ascitic tumors . Comparative studies utilizing a methylcholanthrene-induced fibrosarcoma as well as solid and ascitic forms of P815 mastocytoma and Ehrlich tumor demonstrate that responsiveness to tumor migration inhibition factor is not merely a property conferred upon tumor cells by prior animal passage in suspension . These results provide a further suggestion that the capacity for lymphokine-induced migration inhibition is a general property of tumor cells . This in turn raises the possibility that this capacity might vary in a predictable manner with malignant potential. Tsitologiia, 1984 Sep, 26(9), 983 - 95 {Cell electrophoresis}; Sungurov AIu; The physical principle of cell electrophoresis, the role of media pH and ionic strength, and the nature of cell coat electric charge are considered . The advantages and defects of analytic and preparative cell electrophoresis variants are analyzed . The results of use of cell electrophoresis for studying and separation of erythrocyte, leukocyte and bone marrow cell suspension are presented. Parasite Immunol, 1984 Sep, 6(5), 435 - 42 Antigen-specific and concanavalin A-induced lymphocyte blastogenesis responses during the course of Plasmodium berghei infection in rats; Raybourne R et al.; Antigen specific and concanavalin A (Con A)-induced lymphocyte blastogenesis responses were monitored in the spleens of rats infected with Plasmodium berghei . Con A responses were depressed only at the time of peak parasitaemia . The antigen specific blastogenesis response was either not in evidence, or at a low level during the periods of patent or subpatent infection (up to 8 weeks after infection) . Higher levels of blastogenesis were seen from 8 to 12 weeks after infection, which correlates with clearance of subpatent infection . Fractionation of immune spleen cell suspensions on nylon wool columns indicated that purified T cells did not respond to parasite antigen. Exp Cell Res, 1984 Sep, 154(1), 125 - 35 Isolation and characterization of vitamin-A-storing lung cells; Okabe T et al.; Vitamin A-storing cells have been shown to be distributed among various organs and tissues, including the lungs . In order to investigate this unique type of cell, the in vitro isolation has been carried out from rat lungs . Lungs were perfused with EGTA and collagenase solution in situ, and were digested with trypsin-collagenase solution at 60-min intervals for 2 h . Then, the cell suspensions obtained were incubated at 37 degrees C in F-10 medium supplemented with 10% fetal bovine serum (FBS) for 72 h . Non-adherent cells were then removed by vigorous washing with medium, and the resultant cell monolayer was harvested with trypsin to remove the contaminating macrophages . These cell fractions were shown to contain more than 96% of vitamin A-storing cells, judged by electron and fluorescence microscopic examinations . The cells grown in vitro retained well the overall morphology characteristic of the vitamin A-storing cells found in lung tissues . The isolated cells grew well in vitro and the growth was inhibited by D-valine or cis-hydroxyproline . The progeny of the cells still contained vitamin A lipid droplets after several transfer generations . Characteristic networks of fibronectin were also demonstrated around the cells . These results have shown that vitamin A-storing cells in the lung was successfully isolated from rat lungs and the cells possessed fibroblast-like characters storing vitamin A in small lipid droplets. Clin Exp Immunol, 1984 Sep, 57(3), 614 - 20 Peripolesis followed by cytotoxicity in chronic idiopathic inflammatory bowel disease; Wilders MM et al.; Antigen presenting veiled cells have recently been described in cell suspensions prepared from the gut wall of patients with chronic idiopathic inflammatory bowel disease (CIBD) . The normal gut wall is virtually devoid of these cells . In this report we describe a phenomenon known as peripolesis studied by phase contrast cinematography . This is a process in which lymphocytes are seen to wander around larger target cells . These could be identified ultrastructurally as Ia positive veiled cells . In most cases peripolesis was followed by lysis of the target cell . Peripolesis was recorded i