Adv Exp Med Biol, 1981, 142, 301 - 8 Persistent infection with mouse hepatitis virus, JHM strain in DBT cell culture; Hirano N et al.; After inoculation with JHM strain into DBT cell monolayers, a persistently infected DBT cell culture was established without producing typical cytopathic changes after about 15th passages . By immunofluorescence virus specific antigen was demonstrated in 10 to 15% DBT cells . This persistently infected culture (JHM-CC) was resistant to superinfection with parental JHM, but such resistance was not shown against vesicular stomatitis virus . JHM-CC virus produced small plaques on DBT cell monolayers . Temperature sensitive (TS) mutant, defective interfering (DI) particle or interferon was not detected in the JHM-CC . To intracerebral inoculation with JHM-CC virus, cortisone treated ICR mice survived without showing clinical signs, however, demyelinating lesions were produced in the brain and spinal cord of them. Med Microbiol Immunol (Berl), 1981, 170(2), 83 - 9 Hepatitis A virus in cell culture . III . Propagation of hepatitis A virus in human embryo kidney cells and human embryo fibroblast strains; Flehmig B et al.; The propagation and adaptation of hepatitis A virus (HAV) in human embryo kidney cells (HKC) is shown . The growth curve of HAV in the first passage through HKC is compared to the growth curve in the tenth passage through HKC . It is shown that in the course of 18 passages through HKC, HAV adapted to these cells causing the virus to grow much more rapidly . The cell-bound HAV is compared to the HAV released in the cell-culture supernatant during the ninth passage through HKC . The HAV from the tenth passage through HKC is shown to be able to replicate also in a human embryo fibroblast strain (HFS) . Furthermore, adaptation of the HAV to HFS is demonstrated. Med Microbiol Immunol (Berl), 1981, 170(2), 73 - 81 Hepatitis A virus in cell culture . II . Growth characteristics of hepatitis A virus in Frhk-4/R cells; Flehmig B; The propagation of hepatitis A virus (HAV) is shown in a rapidly growing fetal rhesus monkey kidney cell line (Frhk-4/R) . In the course of ten passages through Frhk-4/R cells the HAV, which was released in the supernatants of the cell cultures, was adapted to these cells . In the tenth passage 6 days after infection, it was possible to detect low amounts of HAV in the supernatants by radioimmunoassay (RIA) . With indirect immunofluorescence 3 days after infection, a specific granular fluorescence was demonstrated in the cytoplasm of cells infected with HAV from the tenth passage . A persistent infection of Frhk-4/R cells appeared with a main peak at a density of 1.32 g/cm(3) in CsCl density gradients . In the 1.32 g/cm(3) fractions, typical HAV particles are shown by electron microscopy . Furthermore the HAV produced in Frhk-4/R cells is shown to be a useful antigen for diagnostic tests. Microbiol Immunol, 1981, 25(10), 1077 - 86 T cell growth factor from human splenic cell cultures: conditions for its production, and its utilization for maintenance of cytotoxic T cell lines; Tanaka Y et al.; We prepared the T cell growth factor (TCGF) from human spleen cell cultures stimulated with phytohemagglutinin (PHA) . Various cell culture conditions and agents supporting the active TCGF production of the spleen cells were examined . The highest TCGF activity was obtained in the supernatants under the conditions that 2 x 10(6)/ml spleen cells were stimulated with PHA for 48 hr . Production of TCGF from spleen cells depended markedly on their individual sources . Addition of indomethacin to the culture or irradiation of the responding spleen cells increased TCGF activity in the supernatant of the culture . Further, addition of irradiated cells of an Epstein-Barr virus (EBV)-transformed lymphoblastoid cell line (LCL) to spleen cell cultures stimulated with PHA greatly enhanced TCGF production . Human splenic TCGF facilitated the establishment of human cytotoxic T cell (Tc) lines specific for EBV-transformed LCL cells when those Tc line cells were stimulated periodically with irradiated autologous LCL cells but not with the other two types (K-562 or Molt-4) of cells . Allogeneic LCL stimulators allowed the Tc line cells to proliferate . However, Tc line cells cocultured once with allogeneic LCL stimulators no longer exhibited EBV-specificity in their cytotoxicities. Physiol Chem Phys, 1981, 13(3), 281 - 7 Inhibition of protein synthesis in cell cultures by vanadate and in brain homogenates of rats fed vanadate; Montero MR et al.; Following the observation of polysome disaggregation by vanadate, when Neuro-2a cells were incubated with vanadate, incorporation of 3H-leucine into protein was markedly inhibited . The inhibition of protein synthesis was dependent on vanadate concentration and on time of incubation . Inhibition of cell growth was also observed . Simultaneous measurements on vanadate-treated cells showed decreased Na,K-ATPase activity . Rats given sodium vanadate as their sole drinking fluid also showed an inhibition of brain protein synthesis (18 and 20% after 30 and 60 days, respectively, of treatment) . Possible implications of the inhibition of Na,K-ATPase and of protein synthesis by vanadate are discussed. J Neurosci Res, 1981, 6(3), 293 - 301 Synthesis of lipids in mouse brain cell cultures during development; Siegrist HP et al.; Several metabolic activities in dissociated cultures of newborn mouse brain were compared to the situation in vivo . The developmental activity pattern of cerebroside-sulfotransferase, cyclic nucleotide phosphohydrolase, and beta-hydroxy-beta-methyl glutaryl-coenzyme A-reductase and the synthesis and deposition of sulfatide and cholesterol in culture were estimated . The enzyme activity patterns in vivo and in culture are the same . Since the cultures show very little myelin formation, the parallel increase of enzyme activities necessary for myelination in vivo and in culture suggest the existence of intrinsic factors regulating the biochemical differentiation . In addition, the formation of the products, determined in culture, follows the patterns of the enzyme activities . Dissociated brain cell cultures are therefore a valid model for the study of biochemical parameters related to the synthesis of brain lipids during development. J Recept Res, 1981, 2(2), 175 - 201 On the dynamics of abrin binding to receptor sites in normal and Epstein Barr Virus transformed lymphocyte cell cultures; Witten M et al.; The effects of treatment with varying doses of abrin, a D-galactose binding lectin, on DNA an protein synthesis of normal and Epstein Barr Virus transformed lymphocytes has been investigated . Activation, stimulation, and relative toxicity factor indices are studied, as well as possible relationships between DNA and protein synthesis rates, as measured by simultaneous tritiated thymidine (3H-TdR) and 14C-leucine uptake . Studies of the two new indices, the metabolic self and cross coupling indices lead to the prediction that there are three morphologically distinct subpopulations of EBV-transformed lymphocytes with different abrin receptor site concentrations . This prediction is supported by SEM morphological differences . Using data on EBV-transformed lymphocyte cell density as a function of time and dose of abrin, one can demonstrate that the mean number of receptors bound-EBV-lymphocyte needed to exert a biological influence lies in the interval 59,264 receptors/cell to 370.040 receptors/cell . Using a simple packing model, one can demonstrate that a theoretical estimate places the number of binding sites between 57,600 receptors/cell and 360,000 receptors/cell. J Membr Biol, 1981, 61(3), 155 - 72 Regulation of passive potassium transport of normal and transformed 3T3 mouse cell cultures by external calcium concentration and temperature; Ernst M et al.; Regulation of passive potassium ion transport by the external calcium concentration and temperature was studied on cell cultures of 3T3 mouse cells and their DNA-virus transformed derivatives . Upon lowering of external calcium concentration, passive potassium efflux generally exhibits a sharp increase at about 0.1 mM . The fraction of calcium-regulated potassium efflux is largely independent of temperature in the cases of the transformed cells, but shows a sharp increase for 3T3 cells upon increasing temperature above 32 degrees C . In the same range of temperature, the 3T3 cells exhibit the phenomenon of high-temperature inactivation of the residual potassium efflux at 1 mM external calcium . At comparable cellular growth densities, the transformed cell lines do not show high-temperature inactivation of "residual" potassium efflux . These results are consistent with the notion of a decisive role of the internal K+ concentration in the cell-density dependent regulation of cell proliferation . In particular, the growth-inhibiting effect of lowering the external Ca2+ concentrations is considered as largely due to a rise of passive K+ efflux and a subsequent decrease of internal K+ concentration . The experimental data on the Ca2+ dependence of passive K+ flux are quantitatively described by a theoretical model based on the constant field relations including negative surface charges on the external face of the membrane, which cooperatively bind Ca2+ ions and may concomitantly undergo a lateral redistribution . The present evidence is consistent with acidic phospholipids as representing these negative surface charges. Arch Virol, 1981, 68(3-4), 203 - 9 Inhibitory effects of foscarnet on herpesvirus multiplication in cell culture; Schnurer J et al.; The effect of phosphonoformate (INN; foscarnet sodium) on Herpes Simplex Virus type 1 replication in cell-culture has been studied . At 55 microM, foscarnet reduced the yield by 50 per cent which correlated well with a 50 per cent reduction of plaque formation at 60 microM . Foscarnet had to be added before 8 hours post infection to inhibit virus production . The inhibition of herpesvirus plaque formation by the presence of foscarnet for 24 hours was not reversed by the removal of the drug . The inhibition of virus replication by foscarnet could, in contrast to the inhibition by acycloguanosine, not be reversed by addition of deoxynucleosides. Vopr Virusol, 1981 Jan-Feb, (1), 114 - 7 {Study of viral contamination of Japanese quail and cell cultures from their embryos}; Bogomolova NN et al.; Agents identified as adenovirus CELO were isolated from organ suspensions of 1500 Japanese quails (JQ) in 4 experiments . No contaminating viruses were found in examinations of cell cultures prepared from the kidneys of 80 JQ . Negative results were obtained in examinations of 163 antigens from JQ organs in the COFAL test . Agents identified as mycoplasma were isolated in 16 cases from 736 specimens of the virus-containing fluid used for manufacture of measles virus . According to the results of the CFT, 59 antigens prepared from Japanese quail embryo cell cultures contained no oncornavirus antigens and were negative in the COFAL test . Among 1848 JQ sera examined for the presence of antibody to leukemia-sarcoma complex viruses only 2 sera were found in 1976 to contain antibody to Rous sarcoma virus . No antibody to Marek disease virus in 414 serum samples or to Newcastle disease virus in 554 sera were detected . Among 500 sera tested 30.8% contained antibody to adenovirus CELO. Eur J Clin Pharmacol, 1981, 19(6), 417 - 21 Effects of Pexid on liver cell cultures . Ultrastructural and histoenzymological studies; Lageron A et al.; The effects of different doses of Pexid on cultured liver cells have been studied by ultrastructural and histoenzymological techniques . Two types of abnormal lysosomal inclusions were seen: clear matrix inclusions with either homogeneous or tiny lamellar structures, and dark matrix inclusions with clear vacuoles and either random or myelin-like lamellar structures . These patterns correspond to storage of triglycerides, phospholipids and gangliosides, either singly or together. J Virol, 1981 Jan, 37(1), 216 - 25 Restricted replication of human hepatitis A virus in cell culture: intracellular biochemical studies; Locarnini SA et al.; When hepatitis A virus was inoculated into Vero cells, virus-specified protein and RNA synthesis was detected . Production of viral protein was detected by electrophoretic analysis in polyacrylamide gels by using a double-label coelectrophoresis and subtraction method which eliminated the contribution of host protein components from the profiles of virus-infected cytoplasm . Eleven virus-specified proteins were detected in the net electrophoretic profiles of hepatitis A virus-infected cells . The molecular weights of these proteins were very similar to those detected in cells infected with poliovirus type 1 . Virus-specified protein synthesis could be detected at 3 to 6 h and continued for at least 48 h postinfection, but no significant effect on host-cell macromolecular synthesis was observed . Limited viral RNA replication occurred between 2 and 6 h postinfection . The genomic RNA of hepatitis A virus was extracted and shown to be capable of infecting cells and inducing the same set of proteins as intact virus, indicating that the RNA genome is positive stranded . Progeny virus was never detected in the supernatant fluids of infected cell cultures, and the cells showed no observable cytopathology, even though hepatitis A virus-specific proteins and antigens were being produced . The nature of the defect in the replicative cycle of hepatitis A virus in this system remains unknown. J Clin Microbiol, 1981 Jan, 13(1), 206 - 8 Application of a human osteogenic sarcoma cell culture for detection of human cytomegalovirus antibody by immunofluorescence tests; Furukawa T et al.; A human osteogenic sarcoma cell culture is useful in the immunofluorescence serological test for detecting human cytomegalovirus antibody . These sarcoma cells are chronically infected with human cytomegalovirus and provide a constant number of immunofluorescence-positive cells. Int J Cancer, 1981, 27(4), 487 - 91 Cell-mediated suppression of tumor immunity has a non-specific component . II . Evidence from cell culture experiments; Hellstrom I et al.; In vitro studies were performed to search for cells in the thymus of BALB/c mice with MCA-induced sarcomas which could suppress either a secondary immune response to MuLV-associated tumor antigens present on a Moloney leukemia virus-induced lymphoma, LSTRA, or a primary cytotoxic response to C57BL/6 alloantigens . They showed that thymocytes from mice with sarcomas were suppressive in both systems, and that suppression was independent of whether or not the sarcomas expressed MuLV antigen gp70 . Furthermore, normal thymocytes, when combined with mitomycin-C-treated cells from any of several different MCA-induced sarcomas, suppressed the in vitro generation of a secondary cytolytic response to LSTRA . We postulate that exposure of mice to certain tumor antigens induces cells which, in the presence of the same tumor antigens which are not detectably present on the tumor cells inducing the response. Dev Neurosci, 1981, 4(3), 181 - 7 Developmental changes of the GABA and polyamine systems in isolated neurons in cell culture; Seiler N et al.; Dissociated cells of cerebral hemispheres from 8-day-old chick embryos were cultivated for 8 days in polylysine-coated Petri dishes . Changes of DNA, RNA, total proteins, putrescine, spermidine, spermine, free amino acids and enzymes involved in polyamine and GABA metabolism were studied throughout neuronal development in culture . The presence of GABAergic neurons in the cultured cell population was demonstrated . There were time-dependent changes in cellular polyamine concentrations and the activities of the enzymes involved in polyamine metabolism . Since no significant proliferation took place after the first day in culture, the observed changes indicate a role of polyamine metabolism during neuronal differentiation; it was not possible, however, to attribute the observed changes to specific functions . This culture system seems especially useful for the study of biochemical and of functional correlations between GABA and polyamine metabolism and morphological and functional developments of neurons. Med Microbiol Immunol (Berl), 1981, 169(3), 179 - 86 Studies with some influenza B viruses in cell cultures, hamsters and hamster tracheal organ cultures; Reeve P et al.; Six influenza B virus strains and one recombinant vaccine strain have been compared in cell cultures, hamsters and in hamster tracheal organ cultures . In cell cultures all strains plaque well with or without trypsin . All strains are restricted in growth above 38 degrees C . The cold adapted attenuated virus, influenza B/AA/1/66, and a cold recombinant, RB77, are also restricted in growth above 37 degrees C and thus have a temperature marker . In hamsters influenza B viruses, except strain B/Lee, grow well in lungs and nasal tissues . Small differences were seen between wild type viruses and the cold adapted irus and its recombinants which may serve as additional markers for attenuation. Zh Mikrobiol Epidemiol Immunobiol, 1981 Jan, (1), 24 - 8 {Improvement in the method of cultivating Halprowiae (Chlamydiae) in cell cultures}; Shatkin AA et al.; Comparative evaluation of several methods increasing the effectiveness of cultivating Halprovia (7 strains of different origins) in L-929 and McCoy cell cultures has shown that the maximum effectiveness can be achieved by supplementing the standard method for the cultivation of obligate intracellular parasites with the method of forced adsorption of Halprovia on the monolayer and the treatment of cells with DEAE dextran or cycloheximide . The peculiarities of detecting cytoplasmic halprovian inclusions in infected cells by staining the specimens with fluorescent antibodies, with Lugol's solution, and according to May-Grunwald-Giemsa are described. Adv Biochem Psychopharmacol, 1981, 28, 159 - 73 Substance P and somatostatin actions on spinal cord neurons in primary dissociated cell culture; Macdonald RL et al.; In this paper, we have demonstrated that two peptides, SP and SRIF, which have been localized to and are released from small DRG neurons, have specific but different actions on mouse spinal cord neurons in PDC culture . SP has been shown to be excitatory by decreasing potassium conductance and to a lesser extent sodium conductance; SP also appeared to evoke release of neurotransmitter . SRIF has been shown to modify neurotransmitter release by a presynaptic action . The extensive experimental control that is possible over neurons in vitro permits precise measurements of specific membrane actions to be made and thus allows hypotheses of cellular mechanisms of peptide actions to be advanced . Predictions made based on these hypotheses should then be tested using intact preparations . A reasonable goal for such studies is a detailed understanding of the cellular and ionic mechanisms underlying actions in the CNS, PNS and gut. Immunogenetics, 1981, 12(1-2), 117 - 27 Generation of lipopolysaccharide-induced interferon in spleen cell cultures . I . Genetic analysis and cellular requirements; Ascher O et al.; Incubation of murine spleen-cell cultures with lipopolysaccharide (LPS) induces interferon (IF) production . Maximal IF levels are obtained after incubation with 100 microgram/ml for 10 h . Two inbred mouse strains differing in their ability to generate LPS-induced IF in spleen-cell cultures were used: C3H/eB, which generates high levels of IF (about 60 units/ml), and C3H/HeJ, which fails to generate detectable quantities of IF . In a genetic analysis these strains were hybridized and IF production was determined in spleen-cell cultures from F1 and F2 generations, and from backcrosses of F1 hybrids to parent strains . The results indicate that, in parent strains, a single dominant autosomal gene is responsible for differences in IF production in spleen cultures . LPS-induced IF in spleen-cell cultures resists pH 2 for as long as 48 h, but is labile to heating at 56 degrees C for 30 min . Both macrophages and lymphocytes must be present in cultures for generation of LPS-induced IF . By using mixed cultures of macrophages and lymphocytes from C3H/eB and C3H/HeJ mice, it was shown that macrophages have to interact directly with LPS to enable IF production in the cultures. Connect Tissue Res, 1981, 8(3-4), 255 - 8 Desmosine radioimmunoassay as a means of studying elastogenesis in cell culture; Starcher BC et al.; Elastin is synthesized by fibroblasts and chondroblasts in cell culture shortly before the cells become confluent . Fibroblasts secrete elastin into the medium as soluble tropoelastin molecules, which form desmosine crosslinks and become constituents of the cell layer only after three weeks in culture . Even then only a small fraction of the available tropoelastin molecules from crosslinks . Conversely, the chondrocytes secrete an elastin which never reaches the media as soluble elastin in significant quantities . Crosslinking occurs immediately in the chondroblast cell layer forming stable, insoluble elastic fibers . Both cells in culture produce lysyl oxidase at approximately the same levels . The reason for the marked differences between these cells in the mode of conversion of soluble elastin to insoluble elastin is not known . The suggestion of Mecham that the extracellular matrix may play a major role in the development of elastogenesis may provide an answer. Adv Biochem Psychopharmacol, 1981, 28, 145 - 57 Somatostatin and cortical neurons in cell culture; Dichter MA et al.; Rat cortical neurons in culture have morphological, physiological and biochemical properties similar to their counterparts in situ . Neuropeptides are synthesized by these cultures and can in situ . Neuropeptides are synthesized by these cultures and can be localized to individual neurons . One such peptide, somatostatin, is produced in relatively large amounts, exists in a discrete neuronal population, and is released in the culture medium . Somatostatin has no detectable effect on membrane potential, resistance, or action potential of cells to which it is applied but does not appear to increase incoming spontaneous postsynaptic potentials in some neurons . Somatostatin potentiates the direct membrane effects of glutamate and aspartate . Somatostatin may play a role as a neuromodulator in mammalian cerebral cortex by potentiating the effects of excitatory neurotransmitter agents. Boll Soc Ital Biol Sper, 1980 Dec 30, 56(24), 2631 - 4 {In vitro action of unsaponifiable edible oils on calf renal cell cultures}; Gallone U et al.; During the research concerning biological effects of the most common edible oils (peanuts, sunflower, maize, soya and rectified olive), the Authors have tested the insaponificable fractions on the calf kidney cellular monosurface . The insaponificable of the maize seeds oil determine a net decrease of the speed growth . It has also been noted a very slight increase of the cells development, in the cultures treated with the insaponificables of some other oils, compared with the samples of those not treated . As comparison substance it has been used 3,4 benzpyrene, because his toxic action on the cells is well known. J Biol Chem, 1980 Dec 10, 255(23), 11149 - 55 The regulation of protein turnover in newborn rat heart cell cultures; Frelin C; The regulation of myocardial protein turnover was studied using newborn rat heart cells in monolayer cultures . Protein accumulation in this model system was regulated by the presence of serum in the culture medium . The influences of serum on the rates of protein synthesis and degradation were investigated . Serum deprivation or arginine deprivation did not modify protein synthesis . In contrast serum strongly inhibited the rates of {3H}leucine release from prelabeled long-lived myocardial proteins . The inhibiting serum factor was found heat-stable, displayed slight species specificity, was of plasmatic origin, and its activity was decreased in the plasma of hypophysectomized rats . Platelet growth factor, which promotes DNA synthesis in heart cell cultures, did not inhibit protein degradation . The influence of known regulators of myocardial protein balance was investigated . Leucine had no influence on protein synthesis and degradation . Supraphysiological concentrations of insulin and growth hormone inhibited protein degradation but only in the absence of serum . It is suggested that these compounds may not be the natural regulators of myocardial protein balance. J Cell Physiol, 1980 Dec, 105(3), 565 - 70 Biophysical properties of human astrocytic brain tumor cells in cell culture; Black PM et al.; For malignant cells cultured from a human astrocytoma, electrophysiological characteristics of the plasma membrane included specific resistivity of 446.82 +/- 279.5 ohm . cm2, specific capacitance of 0.758 +/- 0.52 microfarads/cm2, time constant 0.318 +/- 0.10 msec . The resting membrane potential averaged--14.07 +/- 7.4 mV; the mean input resistance 8.1 +/- 4.0 megohms . The average cell area was 1638 +/- 585 mu2 for contactual and and 1919 +/- 989 mu2 for noncontactual cells . Changes in input resistance and resting membrane potential were observed with increasing time in culture, possibly reflecting cel cycling . There did not appear to be electrical coupling in this cell line. J Neurochem, 1980 Dec, 35(6), 1469 - 72 Production and release of acetylcholinesterase by a primary cell culture of bovine adrenal medullary chromaffin cells; Mizobe F et al.; Bovine adrenal chromaffin cells were isolated and maintained as primary culture monolayers . Total acetylcholinesterase (AChE) activity in the cells increased during the culture period, and AChE activity appeared in the culture medium . We have examined the role of the AChE synthesized by the cells on ACh-evoked release of catecholamine from the cells . A progressive decrease in the efficacy of ACh (5 X 10(-5) M) to evoke release of {3H}norepinephrine from day 3-15 cultures suggests that exogenously applied ACh is hydrolyzed by the nascent AChE synthesized by the cells . These findings provide evidence that chromaffin cells produce AChE and release it into their immediate environment. J Cell Sci, 1980 Dec, 46, 221 - 34 The effects of Con A on cell surface shedding in cell cultures; Doetschman TC; A cell surface immobilizing concentration of Con A inhibits the shedding of {3H}fucose-containing glycoproteins from the surface of chick embryonic leg and breast muscle cell cultures and cultures of the rat skeletal muscle cell line L6 . The Con A-induced inhibition of shedding is much less in the mouse fibroblast cell line 3T3 . In all 4 cell types the lectin inhibits the shedding of some fucosyl-glycoproteins more than others, especially those of a lipid-containing fraction which is excluded in Biogel A-5m chromatography . This differential nature of the Con A effect is not changed by the cytoskeletal disruptors cytochalasin B or colchicine . Con A causes an increase in the amount of trypsin-sensitive surface fucosylglycoprotein in the cell surface and appears to decrease the overall amount of cell surface degradation suggesting the inhibition of shedding caused by Con A is not due to an increase in internalization and degradation . The data suggest that some shedding may occur at specific cell surface sites to which surface materials must laterally migrate. J Exp Biol, 1980 Dec, 89, 85 - 101 Cell interactions in nerve and muscle cell cultures; Christian CN et al.; The neurotransmitter synthesized by a given class of neurones is subject to modification and, indeed, a qualitative switchover in transmitter biochemistry recently has been demonstrated (Furshpan, POtter & Landis, 1980; Walicke, Campenot & Patterson, 1977) . In conjunction with the specification of transmitter biosynthesis that becomes established in a given neurone, a complementary specification of appropriate receptor production is required in any cell functionally post-synaptic to that neurone . An additional requirement of peculiar force in the nervous system has to do with the spatial organization of the receptors in the surface membrane of the post-synaptic cell once the receptors are synthesized . Inappropriately distributed receptors are useless receptors . The perfect registration of a variety of types of presynaptic release sites with high post-synaptic concentrations of appropriate receptors constitutes one of the outstanding features of nervous-system organization that must be accounted for . We report some experiments directed toward understanding the cell biology of regulation of receptor distribution over the surface membrane of muscle cells . Functional synaptic connexions are formed quite early in development and the stability and maturation of synaptic networks is contingent on a number of factors . One interesting contingency is that related to the functional activity of developing networks . Do only those networks survive and mature which are activated by stimuli impinging from the environment? (Wiesel & Hubel, 1963) . Put more simple, are action potentials and synaptic activity essential for neuronal maturation? We address this question in cell culture systems from the mammalian central nervous system. J Gen Virol, 1980 Dec, 51(Pt 2), 263 - 70 Enhanced production of infectious rotavirus in BSC-1 cell cultures by various factors in the presence of absence of trypsin; Begin ME; Bovine rotavirus infectivity for continuous green monkey kidney (BSC-1) cells was enhanced in hypertonic medium and following incorporation of cortisol, retinoic acid and vitamin B12 into the cell culture maintenance medium . The virus yields produced under these conditions were similar whether obtained in the presence or absence of trypsin . Infectivity titres were increased following the incorporation of trypsin in the maintenance medium throughout the infection cycle but remained unchanged after trypsin treatment of infected cell extracts . Bovine rotavirus infectivity was not affected by incorporation of phytohaemagglutinin, thyroid gland extracts or foetal calf serum in similar experiments . Unexpectedly, serum promoted virus growth when used with cells treated with actinomycin D . Marked differences in the stability of the newly produced infectious rotavirus were observed, suggesting that cell permissiveness to rotavirus infection may vary following the physiological state of the host cell. Vet Med (Praha), 1980 Dec, 25(12), 725 - 32 {Isolation of cytopathogenic strains of infectious bursal virus of chickens in cell cultures}; Casnocha E; Five virus strains with cytopathogenic properties for the cell cultures of chick embryo fibroblasts and embryo kidney cells were isolated from chickens clinically suspected of suffering from infectious bursitis . According to the form of cytopathic effect (CPE) on cell cultures, according to chloroform and thermal resistance, nature of nucleic acid (RNA), according to the absence of the production of intracellular inclusions, negative haemagglutination, and according to antigenic identity with the reference strain, the isolates were deemed to belong to the viruses of infectious bursitis . This conclusion was also corroborated by histological and serological studies in isolates of infected experimental animals. Appl Environ Microbiol, 1980 Dec, 40(6), 1133 - 5 Rotavirus concentration from cell culture harvests: trypsin treatment followed by hydroextraction; Ramia S et al.; An 80- to 150-ml amount of calf or simian rotavirus-containing cell culture harvests of MA-104 cells were treated with 50 microgram of trypsin per ml and hydroextracted overnight (4 degrees C) with polyethylene glycol 6,000 . The concentrate was resuspended in 8 to 10 ml of tryptose phosphate broth and plaque assayed . Between 85 and 97% of the input virus could be recovered with a concentration of up to 15-fold. Invest Ophthalmol Vis Sci, 1980 Dec, 19(12), 1477 - 82 Replication of acute hemorrhagic conjunctivitis viruses in conjunctival-corneal cell cultures of mice, rabbits, and monkeys; Langford MP et al.; Acute hemorrhagic conjunctivitis (AHC) viruses--enterovirus type 70 (E70), and coxsackie-virus type A24 (CA24)--infect the superficial cells of the conjunctiva and cornea . We examined the growth of several E70 and CA24 isolates in monkey, rabbit, and mouse conjunctival and corneal (C/C) cells . We found that E70 isolates grew well in monkey (10(6.5) TCID50/ml), rabbit (10(4.5) to 10(5.5) TCID50/ml), and mouse (10(3.5) to 10(6.0) TCID50/ml) C/C cultures and caused cytopathic effects (CPE) . In contrast, CA24 isolates replicated well and caused CPE only in monkey C/C cultures (10(6.5) TCID50/ml) . These results show that E70 isolates grow readily in monkey, rabbit, and mouse C/C cells whereas CA24 isolates replicated in monkey C/C cells only . This finding is consistent with the suggestion that a lower animal reservoir may be a source of human infection by E70 . These cell culture systems may be useful for studying virus-cell interactions and host defenses operating at the surface of the eye and for evaluating the feasibility of prophylactic or therapeutic use of interferon, interferon inducers, and/or antibody for controlling AHC virus infections. Immunobiology, 1980 Dec, 157(4-5), 401 - 6 Studies of the producer cell of herpes simplex virus-induced interferon in mouse spleen cell cultures; Kirchner H et al.; The producer cell of type I interferon was studied in spleen cell cultures of C57BL/6 mice stimulated by inactivated Herpes Simplex Virus (HSV) . Interferon production was not abolished by pretreatment of the spleen cells by anti-theta serum plus complement . The producer cell of interferon was not removed by plastic adherence and was not destroyed by the addition of silica . It was present in spleens of 3 day old C57BL/6 mice and in spleens of nu/nu mice . It was not inactivated by treatment of nu/nu spleen cells by anti-theta serum plus complement . HSV-induced interferon production was abolished by passage of the spleen cells through nylon wool columns and by irradiation (1000 R) of the spleen cells . Collectively these data suggest that in murine spleen cell cultures type I interferon is produced by B cells . However, our data do not allow to rule out that the interferon producing cell may be an immature macrophage or an immature T cell. J Cell Physiol, 1980 Nov, 105(2), 287 - 300 Influence of proliferative rates and A system substrate availability on proline transport in primary cell cultures of the R3230AC mammary tumor; Gay RJ et al.; Regulation of A system amino acid transport was studied in primary cultures of the R3230AC mammary adenocarcinoma . Higher rates of carrier-mediated Na+-dependent proline transport, vc, was decreased and was attributed to a two-fold decrease in Vmax and a two-fold increase in Km . When compared to cells grown in standard media (Eagle's minimal essential medium, MEM), cells grown in media supplemented with A system substrates (alanine, serine, glycine, and proline) demonstrated adaptive decreases in proline transport; the decrease was due to two-fold reduction in Vmax, with no change in Km for proline . Even in the presence of preferred substrates for the A system, a density-dependent decrease in proline transport was manifested . Both fast- and slow-growing cultures maintained in MEM exhibited rapid increases in proline transport when switched to buffers devoid of amino acids; two-fold increases in Vmax were seen within 4 hr, but Km was unchanged . This starvation-induced adaptation was completely prevented by inclusion in the buffer of 10 mM proline, 0.1 mM alpha-(methylamino)-isobutyric acid (MetAIB) or 10 mM serine, whereas inclusion of the poorer A system substrate, phenylalanine (10 mM), had no effect . The effects of MetAIB to prevent starvation-induced increases in proline transport were dose-related, rapid, and reversible . Amino acid starvation-induced increases in proline transport were partially blocked by cycloheximide or actinomycin D . Data were obtained demonstrating a temporal relationship between increasing intracellular {proline} and decreasing vc for proline uptake . In addition, efflux of proline from preloaded cells preceded the increase in initial rates of proline entry . Taken together, we concluded that: 1) A system transport in primary cultures of this mammary adenocarcinoma is regulated by cell density as well as by availability of A system substrates, but these two types of regulation are kinetically distinct; and 2) starvation-induced enhancement of proline transport appears to be due to release from transinhibition, but may also involve a derepression-repression type of mechanism. Tsitologiia, 1980 Nov, 22(11), 1346 - 50 {Reparative DNA synthesis in human and murine embryonic liver cell cultures treated with N-methyl-N'-nitro-N-nitrosoguanidine}; Budunova IA et al.; The carcinogenic agents--UV-light and N-methyl-N'-nitro-N-nitroso-guanidine (NMNG) were shown to induce DNA repair synthesis in human and mouse liver cell cultures . The DNA repair synthesis, measured autoradiographically, was less active in liver cells than in fibroblasts from the same embryo . The hepatocytes exhibited a higher resistance to the toxic effect of both UV-light and NMNG . This phenomenon is suggested to be due to the active non-excision DNA repair in liver cells. Res Vet Sci, 1980 Nov, 29(3), 392 - 3 Cowdria ruminantium (Rickettsiales) in primary goat kidney cell cultures; Jongejan F et al.; Fresh or cryopreserved kidney tissue from goats suffering from heart water (Cowdria ruminantium infection) was infective when inoculated intravenously into susceptible goats . Primary kidney cell cultures were established from 14 goats reacting to C ruminantium infection; they were tested for infectivity by intravenous injection into susceptible goats after periods varying from five to 31 days . Three cultures, five, 12 and 13 days old, induced heartwater in recipients . The other 11 cultures, varying in age from six to 31 days, did not cause any reaction and all 11 recipient goats died from heartwater on challenge . C ruminantium could not be detected microscopically in the cell cultures. Cancer Lett, 1980 Nov, 11(1), 63 - 73 Establishment of a cloned line of Lewis Lung Carcinoma cells adapted to cell culture; Bertram JS et al.; A cloned line of cells adapted to culture has been isolated from the Lewis Lung Carcinoma and has been designated the Lewis lung carcinoma line 1 (LLC1) . It grows as a monolayer culture in RPMI 1640 medium supplemented with 2% fetal calf serum with a plating efficiency of about 94% and a doubling time of 21 h . LLC1 cells remain highly tumorigenic in C57B1 mice and produce primary tumors and lung metastases histologically indistinguishable from the original tumor line . The doubling time for a subcutaneous tumor derived from LLC1 cells was 23 h for a tumor mass of about 0.1 g and 40 h for a tumor mass of about 1 g . The cell line forms discrete colonies on a plastic substrate and can be used in a focus assay to determine drug induced cytotoxicity . Results with a number of chemotherapeutic agents are reported; in general, sensitivity measured in vitro does not correspond with published reports of sensitivity of the Lewis Lung carcinoma in vivo. Biomed Mass Spectrom, 1980 Nov, 7(11-12), 529 - 32 A method for the analysis of catecholamines by selected ion monitoring and 14C isotope dilution in adrenal medullary cell culture; Lhuguenot JC et al.; Extracts have been made from culture medium of rat medullar adrenal cells developed in tissue culture in this laboratory . After pentafluorobenzylimine-trimethylsilyl ether formation the catecholamine derivatives were characterized by gas-liquid chromatography chemical ionization mass spectrometry . In order to assess the catecholamine production capabilities of the cells in culture, a mass spectrometric method with isotope dilution has been devised . Chemical ionization selected ion monitoring allows specific detection at the nanogram level in a higher mass range (400-600 amu) than in the electron impact mode . The isotopic dilution method with 14C catecholamines gives rise to accurate measurements and linear response in the picomole range . The use of the {M-15}+ ion for monitoring m/z values minimizes errors in selected ion monitoring analysis . The results obtained are computerized and treated by the data system for fine background subtraction when high sensitivity and accuracy are required. J Microsc, 1980 Nov, 120(Pt 2), 225 - 8 Description of a coverslip holder for, and observations on, the critical point drying of cell cultures; Evers P et al.; The elimination of artefact during the preparation of cell cultures for scanning electron microscopy is difficult . Collapse of cellular projections, cytoplasmic cracks, perforations and fracturing of cell-cell processes and cell-substrate attachments occur during fixation, dehydration and critical point drying . Coating and storage may cause further artefact . A specimen holder which serves to minimize turbulence in the critical point dryer and which allows for the simultaneous processing of up to five coverslips, as well as a reproducible technique for the preparation of cell cultures are described. Pediatr Res, 1980 Nov, 14(11), 1226 - 9 Theophylline reduces the activity of cerebroside-sulfotransferase, a key enzyme in myelination, in cell cultures from newborn mouse brain; Siegrist HP et al.; Theophylline, a drug used in neonatology for the treatment of apnea, affects cholesterol synthesis if administered in concentrations of 10(-4) M (a concentration found in serum of treated patients) for 24 hr to dissociated brain cell cultures . The rate-limiting enzyme of cholesterol synthesis, beta-hydroxy-beta-methylglutaryl-coenzyme A reductase (EC 1.1.1.34), is lowered to 45% 48 hr after removal of theophylline . At the same time, cholesterol content of the cells is lowered to 73% . Inasmuch as the phospholipid content of the cells remains stable, the treatment changes the cholesterol phospholipid ratio . Concomitant to this effect, the activity of cerebroside-sulfotransferase (EC 2.8.2.11) is lowered to 60% of control values . We postulate that these two effects are linked to each other by means of modulation of the cerebroside-sulfotransferase activity by membrane lipids. Tsitologiia, 1980 Nov, 22(11), 1339 - 45 {Causes of the preferential action of imuran on the viability and proliferative activity of a Chinese hamster cell culture in the stationary growth phase}; Makarova GF et al.; It has been shown that the active principle of imuran, 6-mercaptopurine, exerts a similar though less pronounced effect on viability and proliferative activity of Chinese hamster cells by affecting them preferentially in the stationary phase of growth . This effect cannot be attributed to the inhibition by imuran of xanthine oxidase, as proposed earlier, since another inhibitor of this enzyme, allopurinol, appears more effective, causing more cell deaths during exponential growth phase rather than during stationary growth . Other possible grounds for different cytotoxic effects of imuran depending upon the proliferative status of a cell have been discussed. Tohoku J Exp Med, 1980 Nov, 132(3), 267 - 76 Correlation between the mixed lymphocyte tumor cell culture reaction (MLTR) and some histological characteristics in esophageal cancer; Kuriya Y et al.; The mixed lymphocyte tumor cell culture reaction (MLTR) using autochthonous peripheral and lymph node lymphocytes was performed on 21 patients with esophageal cancer . Ten of 16 cases (62%) in peripheral lymphocytes and 9 of 16 cases (56%) in the lymph node lymphocytes showed positive reaction . There was no correlation between stimulation index (SI) and the degree of lymph node metastasis which is one of the determinants of clinical stage (Guide Lines for the Clinical and Pathologic Studies on Carcinoma of the Esophagus, 1976) . Many cases showed positive reaction in MLTR even if their tumors were at advanced stage . SI of MLTR on the patients who died of a relapse in a short time within one year after operation was found to be low levels . There was no remarkable correlation between MLTR and PPD skin reaction . The results of MLTR were compared with histologic differentiation grades of tumor tissues; intraepithelial spread, vascular invasion, sinus histiocytosis of the regional lymph nodes, and follicular hyperplasia of the regional lymph nodes . There was a minor correlation between the results of MLTR and sinus histiocytosis of the regional lymph nodes, and follicular hyperplasia of the regional lymph nodes . There was a minor correlation between the results of MLTR and sinus histioction . The results of MLTR were compared with histologic differentiation grades of tumor tissues; intraepithelial spread, vascular invasion, sinus histiocytosis of the regional lymph nodes, and follicular hyperplasia of the regional lymph nodes . There was a minor correlation between the results of MLTR and sinus histiocytosis of the regional lymph nodes. J Cell Physiol, 1980 Nov, 105(2), 197 - 207 The use of 5-bromodeoxyuridine and irradiation for the estimation of the myoblast and myocyte content of primary rat heart cell cultures; Masse MJ et al.; A method for killing dividing cells (Puck and Kao, '67) was adapted for the elimination of dividing heart muscle cells (myoblasts) in cultures . We have used this method to demonstrate their presence and to estimate their number as well as the number of nondividing heart muscle cells (myocytes) in the neo-natal rat heart . Cells were cultivated in BUdR (5-bromodeoxyuridine) 10(-4) M for 3 days and then irradiated with long UV light . The selective elimination of dividing cells led to a loss of myosin Ca2+-activated ATPase in the cultures . This indicates the presence of dividing cells which contain myosin . The percent of ATPase left after irradiation was 32% of the control in cultures derived from 1-day postnatal rats and 48% in cultures from 4-day postnatal rats . This reflects an in vivo shift of myoblasts to myocytes in the muscle cell population as the rat ages. Vopr Virusol, 1980 Nov-Dec, (6), 676 - 8 {Species specificity study of swine leukocyte interferon on different cell cultures}; Pokidysheva LN et al.; The antiviral effect of swine leukocyte interferon was studied in cell cultures of different origins . Swine leukocyte interferon was demonstrated to protect human diploid fibroblasts . The cultures of primarily trypsinized mouse embryo fibroblasts and continuous bovine embryo tracheal cells are as sensitive to swine leukocyte interferon as human diploid cells . Studies of the age sensitivity of mouse fibroblast tissues to swine interferon showed the tissue sensitivity to interferon to decline markedly with age. Clin Exp Immunol, 1980 Oct, 42(1), 67 - 76 Cell division and giant cell formation in Kupffer cell cultures; Pulford K et al.; A method is described allowing the isolation and culture of relatively pure preparations of murine Kupffer cells for long-term morphological and functional studies . In vivo labelling experiments showed no evidence of significant blood monocyte contamination . The use of a density gradient allowed removal of fibroblasts, cell debris and a relative enrichment of Kupffer cells . After 24 hr in culture the cells were phagocytic, contained non-specific esterase and exhibited an Fc receptor . During the first 3 weeks, cell clumps, epithelioid cells and multinucleate giant cells appeared . Mitoses were seen in the Kupffer cells, cell numbers increased and in vitro labelling with 3H-thymidine at 49 days showed that 33% of the cells underwent DNA synthesis in a 24-hr period . Experiments suggested that giant cell formation was produced both by cell fusion and nuclear division . The experiments show that Kupffer cells are capable of cell division and giant cell formation in culture. J Invest Dermatol, 1980 Oct, 75(4), 316 - 21 Isolation and growth of endothelial cells from the microvessels of the newborn human foreskin in cell culture; Davison PM et al.; A procedure for the isolation and in vitro cultivation of endothelial cells from the microvessels of the newborn human foreskin dermis is described . The epidermis was removed from foreskin tissue using a Castroviejo keratotome (0.1 mm shim) . Endothelial cells were released from the dermal vessels by trypsinization of 5 mm2 sections of dermis at 37 degrees C for 40 min . Cells were expressed into Minimal Essential Medium (MEM) containing 10% pooled human serum, collected by centrifugation and plated onto either a plain plastic or a fibronectin treated culture surface . In primary culture the rate of endothelial cell proliferation was dependent upon serum type and concentration being optimal in 50% pooled human serum . High serum concentration in combination with pretreatment of the culture surface with fibronectin was required for maximal proliferation rate, for the cells to achieve confluence and for subcultivation . Primary and subcultured cells were characterized as endothelial by light microscopic, immunofluorescent (Factor VIII associated protein) and ultrastructural (Weibel-Palade body) criteria. J Immunol, 1980 Oct, 125(4), 1724 - 9 Regulation of immune response in allogeneic mixed spleen cell cultures . I . Influence of I-region on the generation of suppressor cells; Kim YT et al.; The immune responses of allogeneic mixed spleen cell cultures (MLC) to the T-dependent antigen, SRBC, and to the T-independent antigen, DNP-PAA, were investigated . The immune response to DNP-PAA in MLC with certain strain combinations was always suppressed as compared with the expected PFC response calculated from the PFC responses of the individual strains . This suppression was eliminated by treating the spleen cells with RAMB antiserum plus complement before the incubation of the MLC with DNP-PAA . It can be concluded that the suppression in the PFC response to the T-independent antigen DNP-PAA in MLC is due to the generation of suppressor T-cells . The PFC response to the T-dependent antigen, SRBC, in MLC showed either suppression, no change, or rarely augmenation, suggesting that the allogeneic mixed spleen cell cultures can generate both suppressor and helper T cells and that the balance between helper and suppressor activity regulates the PFC response to a T-dependent antigen . Suppressor activity was also generated in a one-way MLC, but the degree of suppression depended upon which of the two strains was responding . Similar amounts of thymidine were incorporated in the one-way MLR irrespective of which strains was responding . Thus, the extent of proliferation in one-way MLR is not related to the degree of suppressor activity generated . The results further indicate that a difference between two strains in the I-C, S, and G regions of the major histocompatibility complex is required to generate suppressor activitiy that can depress the response to a T-independent antigen, MLC between strains differing in K, I-A, I-B, I-J, I-E, and D regions generate little or no suppressor activity in this system. Arthritis Rheum, 1980 Oct, 23(10), 1081 - 6 Bone cell cultures as an experimental model; Wong GL; The isolation and separation of bone cells with populations enriched for osteoclastic or osteoblastic phenotypes are described . Such systems offer the opportunity to compare and contrast the controls exerted by hormones, ions, and other agents on the functions of the individual bone cell types and may in the future provide explanation for the changes seen in bone tissue in various diseased states. Gann, 1980 Oct, 71(5), 679 - 85 Lack of correlation among gamma-glutamyltranspeptidase activity, production of alpha-fetoprotein, and transplantability in rat liver epithelial-like cell cultures; Sakakibara K et al.; The expression of two markers of fetal liver, alpha-fetoprotein (AFP) and gamma-glutamyltranspeptidase (GGT), and the relationship between these markers and tumorigenicity were studied in 17 continuous epithelial-like cell lines derived from normal rat livers and ascitic hepatoma cells . Fourteen cell lines positive for GGT activity included 6 non-transplantable lines . Out of 10 cell lines transplantable to syngeneic rats and/or immuno-depressed hamsters, 2 showed no activity of GGT cytochemically . AFP production was seen in the culture fluid of 4 out of 15 cell lines tested . They consisted of 1 GGT-positive, transplantable, 1 GGT-negative, transplantable, and 2 GGT-positive, non-transplantable cell lines . These results indicate that no correlation exists among these 3 parameters related to neoplastic and preneoplastic states of cells. J Gen Virol, 1980 Oct, 50(2), 447 - 50 Induction of delta 3(4) ketosteroid synthesis by interferon in mouse adrenal tumour cell cultures; Chany C et al.; Interferon, like cholera toxin, induces in mouse adrenal YI cells the production of delta 3(4) ketosteroids . In parallel, cyclic AMP (cAMP) is activated . At high concentrations, mouse but not human interferon induces a cell rounding effect, similar to that obtained with cholera toxin . In YI cells transformed by simian adenovirus 7, production of cAMP is still increased by that of steroids is blocked . The role if interferon in these cellular events is discussed. Arthritis Rheum, 1980 Oct, 23(10), 1115 - 20 Cell cultures from bone affected by Paget's disease; Mills BG et al.; Cells obtained from Paget's bone specimens were maintained in culture for up to 8 1/2 months . The cells had several characteristics of bone cells including the presence of alkaline phosphatase, acid phosphatase, or succinic dehydrogenase as demonstrated histochemically . Electron microscopy revealed nuclear inclusions similar to those found in the osterclasts of Paget's disease in 4 or 11 cultures . Immunohistology utilizing specific antisera demonstrated the presence of respiratory syncytial virus antigen(s) in 7 or 7 patients . Negative results were obtained with antisera to a variety of paramyxoviruses. S Afr Med J, 1980 Sep 20, 58(12), 485 - 8 The implications of detecting an extra metacentric microchromosome on amniotic fluid cell culture; Barnard AH et al.; A patient was referred for amniotic fluid cell culture because of advanced maternal age . A decisional dilemma presented itself as a result of the detection of a metacentric bisatellited microchromosome (47,XX + marker) in the amniotic fluid cell culture . The decision whether to terminate the pregnancy had to be considered because the literature revealed a number of cases of an extra marker in patients with single or multiple congenital abnormalities, although other patients with a similar marker were phenotypically completely normal . The finding of an identical marker chromosome in the phenotypically normal mother and two of her off-spring favoured the continuation of the pregnancy . It would appear as if this is the first reported case in which a familial marker chromosome was detected prenatally and the pregnancy permitted to continue to term with the birth of a normal infant. J Biol Chem, 1980 Sep 10, 255(17), 8351 - 61 Biochemical characterization of collagens synthesized by intestinal epithelial cell cultures; Quaroni A et al.; Rat intestinal epithelial cells in culture synthesize and secrete several different collagens as identified by biochemical and ultrastructural criteria . These collagens were labeled with {U-14C}proline, separated by DEAE- and CM-cellulose chromatography, and at least four different collagen chains were identified . Two of them, present almost exclusively as fully processed collagens, were alpha 1(I) and alpha 2 chains . The presence of a large excess of alpha 1 (I) chains over the normal ratio for type I collagen indicated that both type I collagen {alpha 1(I)}2 alpha 2 and {alpha 1(I)}3 or type I trimer were present both in the culture medium and in the extracellular matrix . The labeled alpha 1(I) chain had a CNBr peptide pattern superimposable on that of a standard alpha 1(I) chain from rat skin, but the intact radiolabeled chain differed from the standard in its migration on sodium dodecyl sulfate gels and elution position on CM-cellulose column and had a much higher hydroxylysine content . The other two collagen chains were present in the culture medium exclusively as partially processed procollagens . They constituted 60 to 70% of the collagenous proteins and had features corresponding to none of the known collagen types . They were separated by CM-cellulose chromatography and further characterized . Both contained interchain disulfide bonds in the pepsin-resistant portion of the molecule and, after pepsin digestion, eluted from CM-cellulose at lower salt concentrations than standard alpha 1(I) chain . One of them was characterized by a low hydroxyproline content and a high hydroxylysine content, with all the hydroxylysine present as glycosylgalactosyl derivative . The CNBr peptide patterns of these two unknown chains differed from each other, and did not correspond to those of any standard collagen chain examined . They may represent new collagen types specifically present in the intestinal basement membrane. Biochim Biophys Acta, 1980 Sep 8, 619(3), 650 - 9 Lipoprotein lipase activity in F1 heart cell cultures . Effect of dialyzable serum factors on enzyme stability and enzyme synthesis; Friedman G et al.; F1 heat cell cultures were grown in F-10 medium containing 20% fetal calf and horse serum and after 6-7 days showed high activity of lipoprotein lipase . When the culture medium contained 20% serum which had been dialyzed against F-10 medium, a 75% decline in lipoprotein lipase activity occurred after 3 h of incubation . Cultures incubated with 20% dialyzed serum and dialysate, obtained after 24 h dialysis of serum against F-10 medium, retained full enzyme activity . Restoration of enzyme activity, lost upon incubation with dialyzed serum, became apparent only 2 h after incubation of the cells with dialysate and dialyzed serum and was complete after 24 h . The effectiveness of the dialysate was not affected by trichloroacetic acid precipitation, ether extraction, exposure to pronase or to 80 degrees C for 10 min; it was retained after chromatography of DEAE cellulose but was lost after elution from CM cellulose colums . Addition of spermidine and spermine to culture media containing dialyzed serum did prevent partially the decline in lipoprotein lipase activity of the heart cell cultures . These polyamines were also able to stabilize lipoprotein lipase activity of heart homogenates incubated at 37 degrees C . However, these compounds were not effective in resoration of enzyme activity of cultured cells lost after exposure to dialyzed serum . It appears that positively charged low molecular weight molecules present in sera of various species are required for the stabilization and synthesis of lipoprotein lipase in heart cell cultures. Biomedicine, 1980 Sep-Oct, 33(5), 148 - 50 Induction of erythropoiesis with erythrocyte production in bone marrow cell culture "in vitro"; Mori KJ et al.; In the system of long-term bone-marrow culture described by Dexter et al., the differentiation of hematopoietic stem cells into erythropoietic cells is not observed . In this system, bone marrow are grown in a medium supplemented with horse serum . We describe here the induction of erythrocytic maturation in the bone-marrow culture by the addition of 5% fetal calf serum, one or two weeks after seeding the bone-marrow cells . We obtained the persistance up to 5 weeks of erythrocytic production . This phenomenon does not depend on the presence of erythropoietin in fetal calf serum. Vopr Virusol, 1980 Sep-Oct, (5), 608 - 11 {Combined effect of remantadine (alpha-methyl-1-adamantane methylamine) and ribovirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) on the reproduction of Sindbis virus in cell culture}; Galegov GA et al.; The influence of remantadine, ribovirine, and combination thereof on Sindbis virus reproduction in cell cultures was studied . Comparison of remantadine and ribovirine showed the former to be a stronger inhibitor of Sindbis virus reproduction . The results of the combined effect of both drugs in chick embryo fibroblast cultures showed undoubtful advantages of this treatment over the use of each of the drugs alone . In studies of the effect of ribovirine on synthesis of virus-specific proteins and RNA no inhibition of formation of virus-specific macromolecules was observed. Vopr Virusol, 1980 Sep-Oct, (5), 574 - 6 {Factors responsible for the persistence of rabies virus in cell cultures}; Bogomolova NN et al.; Persistence of rabies virus (RV) was studied in two cell cultures: HEp-2-RV and BHK-RV . The infection was demonstrated in 8% cells of the BHK-RV system and 53% cells of HEp-2-RV system by the method of cloning . The virus-free clones were as sensitive to RV infection as the control cultures . The incubation temperature shifts up to 40 degrees C and down to 34 degrees C did not affect the carrier state . 5-BUDR did not activate the infectious process in the chronically infected cells . The factors possibly responsible for RV persistence in cell cultures are discussed. Vopr Med Khim, 1980 Sep-Oct, 26(5), 677 - 9 {Action of remantadine on virus-specific polypeptide synthesis in a Sindbis virus-infected cell culture}; Lazymova ZA et al.; Effect of remantadine (alpha-methyl-I-adamantane methylamine) on reproduction and synthesis of the virus-specific polypeptides was studied in culture of chicken embryo fibroblasts, infected with virus Syndbis . The preparation inhibited the virus reproduction as well as the formation of virus-specific proteins after addition into the cultural medium together with virus, immediately after absorption and within 1 and 2 hrs after absorption . The data obtained suggest a possibility of an immediate effect of remantadine on the synthesis of virus-specific macromolecules. Exp Hematol, 1980 Sep, 8(8), 1040 - 7 The abrogation of in vivo resistance to parental bone marrow transplantation and of in vitro natural cell-mediated cytotoxicity to the YAC lymphoma by in vivo growth of a transformed thymus-derived cell culture; Gardner FH et al.; A thymus-derived monolayer culture, referred to as E1, from (C57Bl/6 X A)F1 hybrid mice was continuously passaged in vitro for over three years and formed rapidly growing, non-metastasizing tumors when injected s.c . into syngeneic mice . The spleens of tumor-bearing mice were greatly enlarged, but no tumor cells were detected in these spleens . The natural cell-mediated cytotoxic activity of spleen cells of tumor-bearing mice decreased with increasing tumor size . In addition, the expression of genetic resistance to transplantation of C57Bl/6 parental bone marrow cells was decreased in the spleens of irradiated tumor-bearing mice . This correlation between the expressions of natural cell-mediated cytotoxicity and of genetic resistance to bone marrow transplantation is consistent with the hypothesis that both of these responses are mediated by the same population of effector cells. Am J Vet Res, 1980 Sep, 41(9), 1357 - 67 Replication of African swine fever virus in cell cultures; Pan IC et al.; Infection-specific, nonstructural, African swine fever virus antigens, as visualized by the immunofluorescence technique, appeared as fine stipplings, evenly distributed in the cytoplasm and nucleus of Vero cells and in monocytes by postinoculation hour (PIH) 3 . Cytoplasmic inclusion bodies (IB) appeared at PIH 4 and continued to increase in size up to PIH 8 . The viral DNA was solely synthesized within the IB of infected monocytes, as evidenced by an autoradiographic chase experiment; maximum synthesis occurred at PIH 5 . The 2,300-S and 2,500-S (sedimentation coefficient) structural viral antigens were visualized in the IB at PIH 5 and 6, respectively . The infective new progeny of African swine fever virus were formed between PIH 7 and 8, and the cell surface viral antigens were produced between PIH 8 and 9 . Free virus was released between PIH 10 and 11 . Infected cells detached from the glass surface from PIH 13 . The 5-iodo-2'-deoxyuridine interfered with the formation of infective virus, but not interfere with the production of viral antigens. Tsitol Genet, 1980 Sep-Oct, 14(5), 32 - 4 {Marker chromosome study of green monkey cell cultures}; Rodova MA et al.; An investigation of three continuous green monkey cell lines by the C-method of differential staining of chromosomes revealed one marker chromosome in BSC-1 cell line and three marker chromosomes in Vero cell line . Two variants of CV1 cell line (I and II) were sharply different both in the modal class and in the marker chromosomes: a great number of chromosomes and two S-marker chromosomes were characteristic of line I CV1; absence of C-marker chromosomes and the peridiploid chromosome set were characteristic of line II CV1 . These marker chromosomes are enough stable and may be used for the identification of the given cell lines. Endocrinol Exp, 1980 Sep, 14(3), 171 - 82 Modulation of LH-RH stimulated gonadotropin release by progestagens and 17 beta-estradiol in primary pituitary cell culture; Bieglmayer C et al.; Simple trypsination procedure for rat anterior pituitary gland which permits a high yield of viable cells was described . Primary cell cultures set up by this method was characterized for their ability to release gonadotropic hormones into the culture medium with or without stimulation by hypothalamic extracts and a synthetic LH-RH, maximal sensitivity to the latter being found at 3--4 days after plating . Gonadotropin secretion was maximal after 4 hr of incubation with LH-RH, its maximal effective dose (ED50) being between 10(-11) and 10(-10) mol 1(-1) . Such a dose stimulated rLH release into the medium by a factor of about 6 and rFSH secretion by a factor of 3 over controls . The preincubation of cultures wih progesterone, D-norgestrel and delta 15-D-norgestrel resulted in a progestagen dose-dependent desensitization of the cell cultures against LH-RH for both gonadotropic hormones . This effect of progestagens was found to be time-dependent and maximal inhibition was found after 12-20 h . However, more effective inhibition of LH-RH stimulated rLH release was caused by preincubation with cycloheximide suggesting the importance of protein synthesis in the course of LH-RH augmented gonadotropin release . A dissociation of sensitivity of cultured cells against LH-RH concerning their rLH and rFSH release was also found after preincubation with a mixture of progesterone and estradiol . Present data and previous observations strongly suggest the modulatory influence of steroid hormones on LH-RH provoked gonadotropin release at the pituitary level. Proc Natl Acad Sci U S A, 1980 Sep, 77(9), 5507 - 11 Expression of cloned hepatitis B virus DNA in human cell cultures; Hirschman SZ et al.; DNA was isolated from the ayw subtype of hepatitis B virus (HBV) that had been incubated in vitro with all four deoxynucleoside triphosphates in order to complete the circular viral genome by means of the endogenous DNA polymerase . The purified viral DNA was cleaved with EcoRI restriction endonuclease, inserted into the EcoRI site of plasmid pBR322, and cloned in Escherichia coli chi 1776 . DNA from a clone, pHBV-1, that contained a 3200-base-pair insert of HBV DNA was cleaved with EcoRI and incubated with phage T4 ligase under conditions favoring intramolecular ligation . HeLa cell cultures exposed to this DNA showed marked cytopathic changes, accompanied by production of hepatitis B core and surface antigens, 11-14 days after subculture . Electron microscopic examination of anti-hepatitis B surface antigen immunoprecipitates from culture media of these cells revealed both 42-nm particles with central cores and 20-nm round particles . Although neither intact circular nor EcoRI-cleaved linear pHBV-1 DNAs evoked these effects in HeLa cells, both cytopathic changes and intranuclear hepatitis B core antigen were detected in HeLa cells infected with Dane particles. J Clin Endocrinol Metab, 1980 Sep, 51(3), 566 - 72 Adrenocorticotropin and lipotropin secretion by dispersed cell cultures of a human corticotropic adenoma: effect of hypothalamic extract, arginine vasopressin, hydrocortisone, and serotonin; Mashiter K et al.; Basal and modulated secretion of ACTH and lipotropin (LPH) by cultures of trypsin-dispersed cells of a biopsy of a human corticotropic adenoma have been examined . ACTH secretion was detectable throughout the period of culture (13 days) but declined steadily from an initial production rate of 238 +/- 124 ng/3 X 10(5) cells/12 h . The time course of secretion showed a slower phase over the first 4 h, with increases up to 12 h . An extract of rat stalk median eminence caused a significant (P less than 0.005) dose-dependent increase in both ACTH and LPH secretion during 30 min . The patterns of response for ACTH and LPH were very similar; both exhibited a decline in the basal release of peptide subsequent to the period of stimulation . The addition of hydrocortisone (0.2 micrograms/ml) did not suppress basal ACTH secretion during 30 min but significantly (P less than 0.05) inhibited stimulation produced by rat stalk median eminence extract . Arginine vasopressin (dose range, 1-9 ng/ml) significantly (P less than 0.025) stimulated both ACTH and LPH secretion during 30 min . The patterns of response were again very similar . Serotonin (dose range, 0.01-10 micrograms/ml) did not affect ACTH secretion during incubations of 30 min to 4 h . The results obtained with the cell cultures of a human corticotropic cell adenoma concur with in vivo findings of incomplete autonomy of secretion, parallel secretion of ACTH and LPH in response to provocative stimuli, and suppression by corticosteroids . The technique has potential for exploring the cellular mechanisms controlling secretion by human corticotropic adenomas as well as the nature of the hormones produced. Acta Pathol Microbiol Scand {A}, 1980 Sep, 88(5), 327 - 37 The fine structure of "dividers" and "non-dividers" in phase II human glial cell cultures; Blomquist E et al.; A method is described which allows a comparison in the transmission electron microscope (TEM) of cells with different remaining proliferative capacity from one and the same culture . The method takes advantage of a mini-cloning technique employing hapatotactic palladium islands in combination with micro-dissection and preparation for TEM of islands carrying various numbers of cells after 10 days in culture, when all miniclones have become density dependent growth inhibited . By means of this technique non-dividers were compared with miniclones of dividers composed of five to eight cells originating from single cells . Moreover, large, immotile cells without peripheral ruffling activity, known to be non-dividers, were compared with small, ruffling cells, known to be dividers, in the reflection-interference mode in sparse cultures of living cells, and in the TEM mode as whole cell preparations after critical point drying of cells cultured on formvar-coated, gold EM-grids . Non-dividers proved to contain a moderate number of residual bodies, well developed Golgi areas, and often branched or circular mitochondria; they were thinly spread over the substratum with many focal points of contact, and large areas of close apposition between cell and substratum. Clin Chim Acta, 1980 Aug 19, 105(3), 325 - 34 Microenzymatic assays for lysosomal enzymes in primary amniotic fluid cell cultures; Bladon MT et al.; A study of three lysosomal enzymes (hexosaminidase, beta-galactosidase and alpha-galactosidase) in normal primary amniotic fluid cell cultures using a microenzymatic assay is presented . No difference in enzyme activity was found between primary and amniotic cell cultures in passage number one . A progressive change in the proportions of hexosaminidase A and hexosaminidase B with time was demonstrated in culture . The feasibility of this procedure for the early prenatal diagnosis of disorders due to lysosomal enzyme deficiency is discussed. Eur J Cell Biol, 1980 Aug, 21(3), 254 - 60 Failure of 84 cell pairs in 26 different heart-muscle cell cultures to build intercalated discs; Gross WO et al.; Cell contacts formed in cultures between embryonic chick-heart cells were studied . In young cultures, living muscle cells were photographed by phase contrast, each time before and after contact . After fixation the contact sites were observed in the electron microscope . One example where connected cells had beaten together for 3 hours is illustrated here . In the case of these four cell pairs, up to 22 subsequent levels of each contact site were examined . The other 80 cases belonged to 25 different cultures of 2nd, 3rd, 5th, 6th, 8th, 13th, 20th, 47th and 64th days of incubation and were collected within 5 years . On the contact sites of these synchronously-beating muscle cells, membrane specializations, such as intermediate junctions (zonula adhaerens) and gap-junctions (nexus-like), were found, seldom accompanied by desmosomes . Nowhere had these specializations developed an appearance necessary to identify an intercalated disc, i.e., with filament insertion on both sides . These contacts show that common pulsation does not suffice for the formation of an intercalated disc . A developing factor for the maturation of heart myocytes in vivo which is not present in most cultures is to be postulated. Neurosci Lett, 1980 Aug, 19(1), 109 - 14 UPD-galactose:ceramide galactosyltransferase activity in dissociated cell cultures from brain hemispheres of newborn rats; Neskovic NM et al.; Primary cultures enriched in oligodendroglial cells were prepared from dissociated newborn rat brain . Enzymatic study revealed the presence of high specific activities of UDP-galactose:ceramide galactosyltransferase (CGalT) and 2',3'-cyclic nucleotide-3'-phosphohydrolase (CNP) . The specific activity of CGalT was twice as high as that of brain . The CGalT activity increased from 16 days in culture, reached a maximum at about 50 days and declined thereafter . The CNP activity reached a maximum after 60-70 days in culture and remained more or less stable in the following period . The results indicate that in oligodendroglial cells in vitro the regulation of CGalT activity proceeds in a manner similar to that of myelinating brain. Zentralbl Bakteriol A, 1980 Aug, 247(3), 283 - 9 {Intensified adsorption of viruses to cell cultures: improved virus isolation? (author's transl)}; Schmidt G et al.; Two procedures to improve virus cultivation from clinical material were evaluated: an intensified adsorption with 0.2 ml inoculum and 20 h rocking in a Bellco rocker and a low-speed centrifugation of the material onto the cultured cells . Prototype strains from 5 virus families (adenoviruses, herpes simplex virus, vaccinia virus, enteroviruses, parainfluenza 2) as well as original specimens from patients (adenovirus, herpesvirus, enterovirus) were studied by endpoint titration in comparison with the standard procedure . In adenoviruses, a quantitative immunofluorescence was performed too . In endpoint titrations, the centrifugation method did almost never lead to an increased virus titer, as compared with the standard method . However, in the immunofluoresence evaluation of adenoviruses the values attained were 3- to 4-fold higher . On the other hand, the intensified adsorption method led to an increased sensitivity in most adenovirus titrations with 4- to 25-fold titer increment, with prototype and original material . The procedure was ineffective in all other viruses studied. J Gen Virol, 1980 Aug, 49(2), 385 - 95 The detection of intracellular retrovirus-like entities in Drosophila melanogaster cell cultures; Heine CW et al.; A Drosophila melanogaster cell line has been examined for the presence of retrovirus particles . When these cells were disrupted and analysed on sucrose density gradients a subcellular fraction with a density of 1.22 g/ml was found to possess endogenous DNA polymerase activity and could catalyse polymerization of deoxynucleotide triphosphates in response to added template primers . The latter activity had the cation and template primer responses expected for reverse transcriptase . A high mol . wt . polyadenylic acid-containing RNA was also purified from this fraction and could be dissociated by heat treatment into 30 to 35S and smaller species . Electron microscopy revealed the presence of torroidal forms reminiscent of intracytoplasmic A-type retrovirus particles within the Drosophila cells . Similar forms were found associated with the subcellular fraction of 1.22g/ml . We concluded that our D . melanogaster cell line contains retroviruses similar, but not identical, to the A-type particles previously described in mammalian and avian cells. Eur J Pharmacol, 1980 Jul 25, 65(2-3), 305 - 8 Pituitary cell cultures contain muscarinic receptors; Taylor RL et al.; The presence of muscarinic receptors in 5-day dissociated cell cultures of rat anterior pituitary glands was detected by atropine-sensitive binding of 3H-quinuclidinyl benzilate (3H-QNB) . Muscarinic receptor levels in cultures were compared to levels of receptors for dopamine and thyrotropin releasing hormone. Vopr Med Khim, 1980 Jul-Aug, 26(4), 525 - 8 {Role of calcium and potassium in regulating prolactin and somatotropic hormone release in cell cultures of rat adenohypophysis}; Gudoshnikov VI et al.; Influence of calcium, potassium and some other ions on prolactin (PRL) and growth hormone (GH) release was studied in primary monolayer cell cultures of rat adenohypophysis . In Ca2-depleted medium the rate of basal secretion of PRL (but not of GH) was decreased . Increase in calcium concentration in the medium up to 5 mM did not influence the PRL release and slightly lowered the rate of GH secretion . Potassium (30 or 55 mM) stimulated PRL and GH release . The effect of potassium was observed only in the presence of calcium . Cobalt (2 mM) strongly inhibited PRL and GH release . In the absence of bicarbonate anions basal PRL and GH secretion was decreased, but calcium-dependent effect of high potassium level (55 mM) on PRL release persisted. Placenta, 1980 Jul-Sep, 1(3), 209 - 21 Sheep trophoblast in monolayer cell culture; Steven DH et al.; Methods are described for the preparation and maintenance of ovine trophoblast in monolayer cell culture, and for the preparation of cultured cells for ultrastructural examination . Monolayers grown from dispersed and explanted primary cultures were maintained in consecutive subcultures for periods of 12 to 16 weeks . Towards the end of the first week of incubation high concentrations as the cultured developed . In the second week of incubation small binucleate cells were seen in cultures prepared for electron microscopy . By the 14th day larger binucleate cells were visible at the outer edges of the developing monolayer, and by the third to fourth week 25 to 40 per cent of the cells in culture were in binucleate form . Mature binucleate cells seeded in primary dispersed cultures did not survive beyond the 14th day . The result suggest that (a) the binucleate cells which first appear in monolayers of cultured trophoblast during the second week of incubation are formed by nuclear division of uninucleate cells and not from mature binucleate cells seeded in primary dispersed cultures; and (b) there may be a correlation between the numbers of binucleate cells present in the monolayer and the rate of production of ovine placental lactogen . Monolayer cultures of sheep trophoblast may well provide a useful and relatively inexpensive experimental system for the study of binucleate cells and the mechanisms of placental hormone production. Biull Eksp Biol Med, 1980 Jul, 89(7), 77 - 9 {Suppressive effect of xenogenic bone marrow cells on antibody formation in a spleen cell culture in vitro}; Vlasov AA et al.; Bone marrow cells from syngenetic and xenogeneic donors of different species were added to splenocyte culture to induce the primary immune response to sheep red blood cells . It has been shown that both xenogeneic and syngeneic bone marrow cells suppress the primary immune response in vitro . A conclusion is made that the suppressant effect exerted by bone marrow cells on the immune response of splenocytes is not liable to xenogenic restriction. Cancer Lett, 1980 Jul, 10(1), 27 - 32 Cell culture tumor promotion experiments with saccharin, phorbol myristate acetate and several common food materials; Sivak A et al.; The BALB/c-3T3 cell neoplastic transformation system was modified to examine the tumor promoting activity of a set of substances . Following initiation of the target cells with 3-methylcholanthrene, treatment of the cultures with phorbol myristate acetate (0.01 microgram/ml; 1.5 X 10(-8) M) during the remainder of the 4-week assay interval resulted in a marked increase in both spontaneous and initiated Type III transformed foci . In contrast, a similar treatment with saccharin at 20, 100 or 500 microgram/ml (0.08, 0.4 or 2.1 X 10(-3) M) did not influence the occurrence of Type III transformed foci and did not result in a promoting response . Sodium ascorbate (2.53 X 10(-3) M) and L-tryptophan (2.45 X 10(-3) M) almost completely inhibited both spontaneous and initiated Type III transformed foci . Calcium pantothenate (2.10 X 10(-3) M) exhibited a marginal promoting effect . Under the conditions of this study in which the classical tumor promoter phorbol myristate acetate was highly active in promoting Type III transformed foci, saccharin was not active as either a direct transforming or promoting agent at doses up to 5 orders of magnitude higher. J Cell Physiol, 1980 Jul, 104(1), 105 - 19 Lack of correlation between effects of tumor promoter TPA on plasminogen activator production, phosphatidyl choline synthesis, and hexose transport in mammalian cell culture systems; Plagemann PG et al.; We have investigated the effects of the tumor promoter 12-0-tetradecanoyl-phorbol-13-acetate (TPA) on plasminogen activator production, hexose transport and metabolism, and the incorporation of choline into the acid soluble pool and into phosphatidylcholine in suspension cultures of mouse L, mouse P388 leukemia, human HeLa, and Chinese hamster ovary cells, and in monolayer cultures of baby hamster kidney (BHK), mouse 3T3, mouse 3T6, and mouse P388D1 macrophage-like cells . BHK, 3T3, P388D1, and P388 cells produced plasminogen activator constitutively, but no significant production was observed in the other cell lines . Plasminogen activator production was induced or stimulated by TPA only in P388 cells (10- to 20-fold by 100 ng TPA/ml) . On the other hand, phosphatidylcholine synthesis was stimulated by TPA only in HeLa cells, and hexose transport, as measured with 3-0-methyl-D-glucose, only in 3T3 and P388D1 cells, as well as in human lymphocytes . The stimulation of hexose transport occurred more rapidly than the induction of plasminogen activator production and seemed to be part of the mitogenic response of cells to TPA treatment . A stimulation of deoxyglucose uptake was similarly limited to 3T3 and P388D1 cells . A significant decarboxylation of carbon 1 of deoxyglucose occurred in P388 and P388D1 cells, but not in Novikoff cells, and any decarboxylation that occurred was not stimulated by TPA . The results indicate that the various investigated responses of cells to TPA are unrelated and occur independent of each other . The time courses of the biochemical responses also differ significantly. J Neurochem, 1980 Jul, 35(1), 155 - 63 Stimulation of ornithine decarboxylase activity in neural cell culture: potential role of insulin; Parker K et al.; Age-dependent decreases in the levels of ornithine decarboxylase activity were observed in the optic lobes, cerebral hemispheres, and midbrain-diencephalon of 6--17-day-old chick embryos . In dissociated cell cultures from chick embryonic brains a similar pattern of declining ornithine decarboxylase activity with time in culture was observed . Ornithine decarboxylase activity in the dissociated brain cell cultures was stimulated by changing the culture medium . The peak stimulatory effect was shown to occur 12 h after changing the medium . Although serum-free medium stimulated ornithine decarboxylase activity slightly, the presence of serum in the medium was the primary stimulatory factor . Both fetal calf serum and heat-inactivated fetal calf serum produced dose-dependent stimulation of ornithine decarboxylase activity . Dialyzed fetal calf sera stimulated ornithine decarboxylase, but to a lower level than that produced by nondialyzed sera . Insulin (0.5--10 microgram/ml) stimulated ornithine decarboxylase activity in a dose-dependent manner in serum free medium . In addition, 10(-2) M-L-asparagine stimulated ornithine decarboxylase activity in serum-free medium. Stain Technol, 1980 Jul, 55(4), 225 - 8 Separation of epoxy-embedded cell cultures from plastic flasks for electron microscopy; Duchateau A et al.; Monolayers of cells grown in ordinary plastic flasks are fixed and embedded "in situ" into Epon . When polymerized at 40 C for 4 days instead of the usual 60 C, the Epon sheet containing the cells is easily detached from the bottom of the plastic container . The Epon sheet is observed by light microscopy as a histological preparation . Ultrathin sectioning of preselected areas can then be carried out in a horizontal plane. Vopr Virusol, 1980 Jul-Aug, (4), 400 - 3 {Growth of Japanese quail embryo cell cultures on DEAE-Sephadex A-50 microcarrier}; Bektemirov GA et al.; The growth of Japanese quail embryo cells on DEAE-Sephadex A-50 microcarrier was studied, and the growth of the cells on different microcarriers was compared . Under the optimal conditions of microcarrier proceedings quail fibroblast cultures could be grown successfully on a microcarrier reaching a cell density per unit surface comparable to that in monolayer cell cultures . Among the microcarriers tested: cytodex, biosylon and DEAE-Sephadex A-50 treated by the author's method, the latter created the best conditions for attachment and growth of cells. Pediatr Res, 1980 Jul, 14(7), 899 - 900 Choline incorporation into lecithin in response to insulin or dexamethasone in homogeneous cell cultures of rat lung epithelial cells and fibroblasts; Sharp MJ et al.; Labeled choline incorporation into adult rat lung alveolar epithelial cells and adult rat lung fibroblasts in monolayer culture was determined after incubation with insulin (Ins) 10 micrograms/ml, Dexamethasone (Dex) 10(-6)M, or no drug (ND) . Incubation periods were 1, 3, 4, and 5 hours . The lecithin (phosphatidyl choline - PC) recovered was separated inot disaturated phosphatidyl choline (DSPC) and unsaturated phosphatidyl choline (USPC) . Results expressed as specific activity per hour (see Table) indicate that the incorporation of choline into PC and USPC was greater in fibroblasts (F) than in epithelial cells (E) whether ND, Dex or Ins was present . For incorporation into DSPC, there was no difference between E and F whether ND, Dex or Ins was present . There was significant increase in choline incorporation into PC or USPC for both cell types when Ins was present, whereas there was no difference for either cell type when Dex was present . Insulin significantly increased choline incorporation into DSPC in E cells only . Dex was no different from ND in DSPC incorporation in either cell type . We attribute the greater lecithin synthesis of the F cells to a more rapid increase in cellular structural lipids in the fibroblast cell . Dex had no effect on either cell type possibly from the short-term exposure or possibly because the effect of dexamethasone on alveolar epithelial cells is mediated by product(s) from other lung cells, and thus requires a mixed cell culture to have its effect . We suggest that further study of isolated homogeneous cell lines will not be fruitful in the evaluation of mechanisms of acceleration of lung maturation. Cancer Res, 1980 Jul, 40(7), 2433 - 6 Prolactin-stimulated growth of cell cultures established from malignant Nb rat lymphomas; Gout PW et al.; A malignant Nb rat lymphoma which in vivo is stimulated by estrogens has been established in suspension culture . The cultured cells grew readily in Fischer's medium supplemented with fetal calf serum (10%) and 2-mercaptoethanol (10(-4) M) . If horse serum was substituted for fetal calf serum, population growth ceased; i.e., cultures became "stationary." Such stationary cultures could be induced to resume active growth by the addition of a pituitary hormone, prolactin (ovine, rat); concentrations as low as 10 pg/ml had a detectable effect . In contrast, other pituitary hormones or estrogens had little or no effect . The evidence in this and an accompanying paper suggests that prolactin (or related substances) has a role in the growth of some cancers of lymphoid origin in rats. Chem Biol Interact, 1980 Jul, 31(1), 19 - 33 Comparison of aryl hydrocarbon hydroxylase and epoxide hydratase . Induction in primary fetal rat liver cell culture; Goujon FM et al.; The activity of aryl hydrocarbon hydroxylase (AHH) and/or epoxide hydratase (EH) is induced in primary fetal rat liver cell culture by benz-{alpha}anthracene (BA), phenobarbital (PB), cigarette smoke condensate (CSC), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and trans-stilbene oxide (TSO) . The response of the two enzymes to the different chemicals varies as follows: (a) AHH is induced by lower concentrations of BA, PB and CSC than those required to significantly induce EH; (b) AHH is selectively induced by TCDD and by low BA concentrations; (c) the kinetics of AHH induction by BA, PB and CSC is faster than that of EH; (d) TSO is a selective inducer of EH . As described earlier for AHH, RNA and protein synthesis and the continuous presence of the inducer are required in the early phases of EH induction . Later when the EH activity has reached a plateau, intact RNA and protein synthesis is not necessary to maintain the enzyme at its optimal value . The removal of the inducer determines a decay of the EH activity, allowing the estimation of a biological tau 1/2 of about 72 h . TSO prevents the AHH induction by PB, but not that mediated by BA and CSC . Added together with PB, BA, CSC or PB plus BA, TSO induces the EH activity in a more than additive manner . This effect is only seen after 6 days of continuous treatment . These results indicate that in this tissue culture model, the mechanism of AHH and EH induction can clearly be dissociated. Biochem J, 1980 Jun 15, 188(3), 937 - 9 Evidence that ligand formation is a mechanism underlying the maintenance of cytochrome P-450 in rat liver cell culture . Potent maintenance by metyrapone; Paine AJ et al.; The loss of cytochrome P-450 in cultured rat hepatocytes can be prevented by substituted pyridines, especially isonicotinamide, 3-hydroxypyridine and metyrapone . The effect of these compounds is independent of protein synthesis, suggesting that they maintain pre-existing cytochrome P-450 . The efficiency of pyridines at maintaining cytochrome P-450 in hepatocyte culture is highly correlated with their ability to bind to this cytochrome, suggesting that ligand formation with cytochrome P-450 prevents its accelerated turnover in liver cell culture. Zentralbl Bakteriol Mikrobiol Hyg {B}, 1980 Jun, 171(1), 25 - 32 {The toxic effect of ethylene chlorohydrin and ethylene glycol on experimental animals and human cell cultures (author's transl)}; Star EG; Ethylene chlorohydrin (2-chlorethanol) and ethylene glycol can originate as by-products during ethylene oxide sterilization . We studied the effect of these subsdtances upon human HeLa cells as well as the conjunctiva and the epithelium of the external genitalia of 35 rabbits . - We found ethylene chlorohydrin to be considerably more toxic than ethylene glycol . 2-chloroethanol did not cause any reactions at our cell cultures in dilutions of 1:100 after 4 h action upon the cells and 24 h observation time . In our experimental animals this concentration had only minimal irritating effects at the external genitalia . Ethylene glycol produced cellular damages in dilutions of 1:10 after 5 d only . Our experimental animals showed no reactions to these concentrations . At the conjunctiva of rabbits dilutions of 1:100 ethylene chlorohydrin and 1:10 ethylene glycol had no effect . After application of 2-chloroethanol 1:100 to the external genitalia minimal irritations were observed . Ethylene glycol in dilutions of 1:5 caused irritations of the conjunctiva and the genitalia of our rabbits . Ethylene chlorohydrin- and ethylene glycol concentrations which had a damaging effect upon our cell cultures of our experimental animals were many times higher than those which might be expected to originate during ethylene oxide sterilization. In Vitro, 1980 Jun, 16(6), 491 - 501 Effect of hormones on growth rates of malignant and nonmalignant human mammary epithelia in cell culture; Klevjer-Anderson P et al.; The individual effects of seven hormones on the in vitro growth rate of different classifications of human mammary epithelium were compared . Hormones used were: 17 beta-estradiol, estriol, progesterone, hydrocortisone, testosterone, prolactin, and growth hormone . Cell cultures included three established breast cell lines and primary monolayer cultures established from breast fluids and excised mammary tissue from 40 women and 4 men . Specimens comprised three classifications: normal, nonmalignant atypical, and malignant . Growth was quantitated in situ and expressed as population doubling time . Principal findings were: (a) estrogens, prolactin,.and growth hormone stimulated growth of normal cells more frequently than growth of malignant cells, whereas testosterone and hydrocortisone stimulated growth of malignant cells more frequently than growth of normal cells; (b) cells cultured from nonmalignant atypias generally showed hormone response profiles intermediate between those of normal and malignant cells; (c) progesterone stimulated the growth of cells from malignant specimens but not the growth of cells from normal and nonmalignant atypical samples. Chem Biol Interact, 1980 Jun, 30(3), 343 - 53 The induction of benzo{a}pyrene-3-mono-oxygenase by singlet oxygen in liver cell culture is mediated by oxidation products of histidine; Paine AJ et al.; The photochemical generation of excited states of oxygen by the mild illumination of culture medium containing 15 microM riboflavin results in a typical induction of benzo{a}pyrene-3-mono-oxygenase in cell lines derived from liver . However, the induction of the mono-oxygenase is not due to an excited state of oxygen directly activating the inducing mechanism inside the cell but is due to the oxidation of a component of the culture medium forming a stable inducer . The present work unequivocably shows that the component oxidised is histidine . The mild illumination of culture medium containing riboflavin therefore converts a physiological component of the medium which is not normally an inducer of the mono-oxygenase into a compound which is as effective an inducer as the classical inducer . The finding that singlet oxygen will oxidise a cell constituent into a powerful inducer is compatible with the hypothesis that excited states of oxygen and their oxidation products may play a central role in the induction of cytochrome P-450 and associated enzyme activities by many chemically unrelated inducers. Cancer Res, 1980 Jun, 40(6), 1781 - 6 Benzo(a)pyrene metabolism in bovine aortic endothelial and bovine lung fibroblast-like cell cultures; Baird WM et al.; The metabolism of {3H}benzo(a)pyrene ({3H}BP) in bovine aortic endothelial and bovine lung fibroblast-like cells in vitro was investigated . Both cell types metabolized BP to organic solvent-extractable and water-soluble metabolites . The major organic solvent-extractable metabolites were 9-hydroxy-benzo(a)pyrene and 3-hydroxybenzo(a)pyrene; 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene, 9,10-dihydro-9,10-dihydroxy-benzo(a)pyrene, and BP quinones were also formed . No glucuronide or sulfate conjugates of BP metabolites were detected . When exposed to {3H}-3-hydroxybenzo(a)pyrene, both cell types metabolized this phenol to water-soluble derivatives, probably through oxidation rather than conjugation of the molecule . These results demonstrate that endothelial cells metabolze BP to a proximate carcinogenic derivative, the 7,8-dihydrodiaol . Thus, efforts to predict the biological effects of hydrocarbons of an organism must take into account possible metabolic activation by endothelial cells as well as by other target tissues . The formation of unconjugated, phenolic hydrocarbon derivatives by bovine cells suggests their use as a model system for studying the contribution of phenols to the induction of biological effects by hydrocarbons. Carcinogenesis, 1980 Jun, 1(6), 487 - 93 The incorporation of O4-methylthymidine into V79A cell DNA when present in the cell culture medium; Saffhill R et al.; When Chinese hamster V79A cells are cultured in the presence of O4-methyl-{6-3H}-thymidine the incorporation of this modified nucleoside into newly synthesised DNA is observed . The radioactivity incorporated has been identified as O4-methylthymidine by digesting the DNA to 3'-monophosphates with spleen phosphodiesterase followed by treatment with alkaline phosphatase to give O4-methylthymidine as the major radioactive product . The radioactivity associated with the latter co-chromatographs with authentic O4-methylthymidine in several chromatographic systems . Once incorporated the modified nucleoside appears to be rapidly removed from the DNA with half-life of 2-3 h . There is no evidence of demethylation of the O4-methylthymidine to give thymidine, in either the culture medium or within the cells once incorporated into DNA . Although the levels of incorporation observed are low, (being only 125 O4-methylthymidine residues per 10(8) thymidine residues at a modified nucleoside concentration of 10(-5) M), they may still be relevant as similar levels are apparently produced in the DNA of the cultured cells on treatment with biologically significant doses of carcinogenic alkylating agents. Br J Haematol, 1980 Jun, 45(2), 245 - 9 Production of colony stimulating activity in mixed mononuclear cell culture; Hellmann A et al.; Culture medium was harvested after co-incubation of mononuclear cells collected and pooled from the peripheral blood of two different normal donors and was tested for colony-stimulating activity (CSA) in agar culture . With bone marrow from normal donors or peripheral blood from patients with chronic granulocytic leukaemia as sources of granulocyte-committed progenitor cells (CFU-c), such mixed mononuclear cell conditioned medium (MMC-CM) showed activity equal to that of unfractionated leucocyte feeder layers and greater than that of CSA prepared from lymphocytes stimulated by phytohaemagglutinin . The addition to plates of 2-mercaptoethanol during the preparation of MMC-CM enhanced CSA release . MMC-CM is thus a convenient source of CSA and its use may be preferable to that of feeder layers when day-to-day reproducibility is essential. Vet Med (Praha), 1980 Jun, 25(6), 359 - 66 {Cell culture preservation by automatic freezing in the adapted Höppler ultrathermostat of the NBE type}; Kabelik V et al.; A description is presented of an adapted ultrathermostat, respecting the requirement for a continuous decrease in temperature by 1 degree C per minute, as necessary for keeping the frozen cultures alive . Viability was evaluated in the primary cells of calf kidneys in the first subpassage and permanent cell lines PK and TL 72 after their freezing and preservation at -192 degrees C for 30 days . In comparison with regularly passaged cultures, the frozen cells had a high viability. J Biochem Biophys Methods, 1980 Jun, 2(6), 331 - 9 A rapid assay to measure collagen synthesis in cell cultures; Jalkanen M et al.; Limited pepsin digestion and precipitation of resistant parts of proteins with perchloric acid on glass-fiber filters has been used as a rapid way to determine the radioactive collagen secreted into fibroblast culture media . The specificity of the pepsin cleavage was tested by digesting {14C}- or {3H}proline- and {3H}tyrosine-labeled procollagens . Radioactivities obtained with this method were comparable with those obtained with collagenase digestions or hydroxyproline determinations . Dialysis of the samples is avoided and the radioactive collagen can thus be determined from the small medium samples obtained from microtest plates . The method was used to localize a collagen synthesis-increasing factor in preparative isoelectric focusing of microphage culture media. J Cell Biol, 1980 Jun, 85(3), 890 - 902 Preparation of separate astroglial and oligodendroglial cell cultures from rat cerebral tissue; McCarthy KD et al.; A novel method has been developed for the preparation of nearly pure separate cultures of astrocytes and oligodendrocytes . The method is based on (a) the absence of viable neurons in cultures prepared from postnatal rat cerebra, (b) the stratification of astrocytes and oligodendrocytes in culture, and (c) the selective detachment of the overlying oligodendrocytes when exposed to sheer forces generated by shaking the cultures on an orbital shaker for 15--18 h at 37 degrees C . Preparations appear greater than 98% pure and contain approximately 1-2 x 10(7) viable cells (20--40 mg of cell protein) . Three methods were used to characterize these two culture t ypes . First, electron microscopic examination was used to identify the cells in each preparation (mixed and separated cultures of astrocytes and oligodendrocytes) and to assess the purity of each preparation . Second, two oligodendroglial cell markers, 2',3'-cyclic nucleotide 3'-phosphohydrolase (EC 3.1.4.37) and glycerol phosphate dehydrogenase (EC 1.1.1.8) were monitored . Third, the regulation of cyclic AMP accumulation in each culture type was examined . In addition to these studies, we examined the influence of brain extract and dibutyryl cAMP on the gross morphology and ultrastructure of each preparation . These agents induced astroglial process formation without any apparent morphological effect on oligodendrocytes . Collectively, the results indicate that essentially pure cultures of astrocytes and of oligodendrocytes can be prepared and maintained . These preparations should significantly aid in efforts to examine the biochemistry, physiology, and pharmacology of these two major classes of central nervous system cells. Prostaglandins, 1980 Jun, 19(6), 865 - 71 Prostaglandin induced shape changes in fibroblasts grown in cell culture; Gotlieb AI; PGE2 induced shape changes in porcine adventitial fibroblasts grown on glass in low density monolayer cell cultures . Incubation of the cells with PGE2 at concentrations of 100 ng/ml and 1000 ng/ml induced rounding of flat fibroblasts within one hours . The rounded cells had a small rim of cytoplasm around the nucleus and from one to several long thin arborizing cytoplasmic processes extending outward along the substratum . Removal of the PGE2 resulted in transient blebbing of the cell membrane of both the cell body and the processes as the cells returned to their flat normal morphology within one hour . The effect could be inhibited by 1% fetal calf serum . PGF2 alpha did not however induce similar changes . This difference between PGE2 and PGF2 alpha is similar to a report on spreading and migration of mouse peritoneal macrophages, and suggests that under certain conditions PGE2 may have the ability to induce shape changes in cells. Cancer Res, 1980 Jun, 40(6), 1990 - 4 Activities of L-dopa decarboxylase and diamine oxidase (histaminase) in human lung cancers and decarboxylase as a marker for small (oat) cell cancer in cell culture; Baylin SB et al.; The neuroendocrine {amine precursor uptake (decarboxylase)} properties of small (oat) cell lung cancer (SCC) have suggested that this neoplasm may have a separate histogensis from the other major types of human lung tumors . We now report that a key element of this concept, L-dopa decarboxylase activity, is present in surgical and autopsy tissues from all forms of lung cancer . Values are highest in SCC lesions; however, lung adenocarcinoma tissues can have considerable activity, and values overlap those for SCC and fall between values for SCC and large cell and squamous cell carcinoma . The distribution of diamine oxidase activity is identical except that even more overlap occurs between the major tumor types . These data may provide further evidence that SCC and other human lung cancers could share a common origin in the bronchial mucosa . In cell cuture, the distribution of the two enzyme activities is different . The average L-dopa decarboxylase activity is much higher (seven separate culture lines) than in the in vivo specimens, and it completely separates these cell lines from non-SCC lung tumors (four lines) . Diamine oxidase is generally low in both SCC cells and non-SCC cells in culture and does not separate the various cell types . L-Dopa decarboxylase activity thus does appear to be a valuabe marker for separating SCC cells from other lung cancer cells in vitro. Antibiotiki, 1980 Jun, 25(6), 464 - 6 {Effect of oxygen on the antiviral activity of human interferon in cell culture}; Krivokhatskaia LD et al.; Antiviral activity of human lymphocytic interferon under conditions of increased oxygen levels in the cell culture was studied . It was found that oxygen had a capacity for increasing the antiviral effect of human interferon in homologous cells . When 20-80% air was replaced by oxygen the interferon titers on an average amounted to 1:113.4-1:124.8 against 1:29.1 in the control . This means that the average titer of interferon in the experiments with oxygen was 4 times higher than that in the control . On the basis of these data it is recommended using interferon in the form of aerosols in conjunction with oxygen for the treatment of viral respiratory infections. Brain Res, 1980 May 19, 190(1), 111 - 21 Physiological identification of GABA as the inhibitory transmitter for mammalian cortical neurons in cell culture; Dichter MA; (1) Rat cortical neurons grown in dissociated cell culture exhibit IPSPs which appear to be generated by an increase in membrane conductance to chloride . (2) The neurons are all sensitive to GABA in micromolar concentrations and GABA mimics the inhibitory transmitter . (3) The neurons are much less sensitive to glycine and insensitive to taurine . (4) Bicuculline and strychnine both block essentially all IPSPs and at the same concentrations block GABA effects . (5) It is concluded that GABA is the main, or only, inhibitory transmitter utilized by the cortical neurons in vitro . The relevance of this conclusion to in situ transmitter identification is discussed. Vopr Virusol, 1980 May-Jun, (3), 323 - 7 {Comparative study of the persistence of 3 RNA-containing viruses in a continuous cell culture of human origin}; Andzhaparidze OG et al.; A comparative study of chronic infecton of HEp-2 cells with tick-borne encephalitis (TBE), rabies (RV), and rubella (RuV) viruses was carried out . Throughout the entire period of chronic infection (CI) no signs of specific cell destruction by these viruses were observed . The infectious virus was regularly demonstrated in the culture fluid and chronically infected cells . The antigenic properties of the persisting viruses did not differ from those of the original strains . The persisting TBE and rabies viruses replicated in the susceptible cells at a higher temperature and formed plaques of a smaller size than the original virus . The number of chronically infected cells producing infectious virus was always less than the number of cells containing the virus-specific antigen . In all three types of chronic infection the cells supported virus persistence at 40 degrees C . In TBE and RuV chronically infected cells interference with heterologous viruses was marked while in HEp-2-RV homologous interference caused by formation of defective interfering particles was observed . Treatment of the cells with BUDR resulted in activation of the infection only in the HEp-2-TBE system . Experiments on transfection of the sensitive cells by using DNA from HEp-2-RV and HEp-2-RuV gave negative results . The importance of various factors in the mechanism of virus persistence in the chronically infected cells under study is discussed. Vopr Virusol, 1980 May-Jun, (3), 315 - 8 {Properties of the rabies virus long persisting in cell cultures}; Bogomolova NN et al.; Properties of rabies virus (RV) persisting in chronically infected cultures (CIC): HEp-2--RV and BHK-RV were studied . RV from the HEp-2-RV system retained its pathogenicity for mice for more than 3 years of observation . RV from the BHK-RV system lost this property after 50 passages in CIC . Both RV variants from CIC formed plaques in CER cells, showed marked immunogenic activity in mice, had no interferon-inducing activity in BHK-21 cells, and were not temperature-sensitive . Electron microscopic examinations of CIC culture fluids showed virions of bullet-like, oval, or spherical shapes. Br J Cancer, 1980 May, 41(5), 800 - 8 Analysis of cell cultures of 3,4-benzpyrene-treated subcutis and subsequent growth in semi-solid medium; Westwood FR et al.; An in vivo-in vitro implantation model has been used to investigate further the early stages of chemically induced s.c . neoplasia in the mouse . Cell cultures of implant-site tissues from control and 3,4-benzpyrene (BP)-treated animals were found to mirror the in vivo tissue reactions occurring at the time of explantation (Westwood et al., 1979) . Cells were classified into 6 different types . The most abundant cell type in later control cultures was of a typical fibroblast morphology . However, a suppression of growth of fibroblast-like cells occurred when BP-treated tissues were explanted, and a selection of growth in favour of the large polygonal Type 5 cells was observed . When grown from BP-treated tissues Type 5 cells were found to be capable of