J Neurol Sci, 1975 Sep, 26(1), 99 - 105 Demonstration of enzymes related to myelinogenesis in established human brain cell cultures; Duch D et al.; CNP, CGalT and PAPS-CST, enzymes involved in myelinogenesis were demonstrated in cultures derived from human brain . Little or no CNP activity could be found in cultures derived from non-neurogenic tissue . Transformation of brain cultures by PML-SV40 virus resulted in a 3 to 10-fold increase in the specific activity of CNP. Cancer Res, 1975 Sep, 35(9), 2475 - 81 Sarcoma-negative leukemia-positive transformed cell culture established from a murine sarcoma virus-induced rat bone tumor; Chan JC et al.; Inoculation of the Soehner-Dmochowski isolate of the Moloney strain of murine sarcoma virus (MSV), designated MSV-SD, consistently leads to the development of bone tumors in the susceptible New Zealand black (NB) rats . Two separate cell cultures have been established from 2 individual MSV-SD-induced NB rat bone tumors . Cells of 1 bone tumor culture, designated RBT-E, are in early in vitro passages . These cells form colonies in agar medium and take up 2-deoxy-D-{3H}glucose at a greatly enhanced rate, 5 times that of normal nontransformed rat embryo cells . Cells of the RBT-E culture release both MSV and murine leukemia virus (MuLV) and therefore contain sarcoma-positive leukemia-positive transformed cells . The other rat bone tumor culture, designated RBT-L, produced MSV at early passages . RBT-L culture has been passaged over 130 times in vitro . Cells of the RBT-L culture form colonies in agar medium and take up 2-deoxy-D-{3H}glucose at an enhanced rate (3 times that of rat embryo cells), indicating the presence of transformed cells within the RBT-L culture . However, cells of the RBT-L culture at late passages (Passage 130 or more) produce only MuLV and no detectable MSV activity (as shown by the lack of tumor-inducing activity and the lack of focus-forming activities by direct assay or by infectious center assay) . Attempts to rescue MSV activity from RBT-L cells by cocultivation with MuLV-producing mouse cells were not successful . The MuLV found in the RBT-L cells, however, is a competent helper virus capable of rescuing the MSV genome from MSV-SD-induced hamster bone tumor cells . All the available evidence supports the notion that late passages of the RBT-L culture contain transformed cells that do not produce conventionally detectable MSV . These cells are referred to as sarcoma-negative leukemia-positive cells . The sarcoma-negative leukemia-positive cells represent a different kind of MSV-induced transformed cells and provide a unique system for studies in search of MSV markers such as MSV-specific antigens and MSV-specific nucleotide sequences. J Gen Microbiol, 1975 Sep, 90(1), 133 - 9 Some properties of the polysaccharide from cell cultures infected with TRIC agent (Chlamydia trachomatis); Garrett AJ; The polysaccharide, elaborated in trachoma-inclusion conjunctivitis (TRIC) agent inclusions, was isolated from baby hamster kidney (BHK) cells grown and infected in suspension cultures . It was characterized by physical, chemical and enzymic methods as a glycogen with an average chain length of 14 to 16 glucose units. J Virol, 1975 Sep, 16(3), 569 - 74 Interferon-directed inhibition of chronic murine leukemia virus production in cell cultures: lack of effect on intracellular viral markers; Friedman RM et al.; Extracellular murine leukemia virus (MLV) reverse transcriptase activity was decreased by interferon treatment in four interferon-sensitive mouse cell lines which were chronic MLV producers . In three cell lines which were relatively insensitive to interferon, extracellular enzyme activity remained unchanged by interferon treatment . The concentrations of interferon used had no effect on DNA synthesis or cell replication of AKR,C+ cells which were chronic producers of AKR-MLV . In AKR,C+ cultures interferon treatment also had no effect on the level of intracellular viral reverse transcriptase activity in spite of an inhibition of extracellular enzyme activity . Treatment of AKRC+ cultures with interferon for 9 days inhibited extracellular viral reverse transcriptase levels throughout the period of treatment; however, the intracellular enzyme activity remained unchanged, and concentrations of viral p30 (gs) antigen were increased in the interferon-treated cells . When the cells were washed to remove interferon, however, virus production rapidly rose and intracellular p30 antigen fell to the levels of untreated AKR,C+ cells . These and previously reported results suggested that in interferon-treated AKR,C+ cells virus production is inhibited at a late step in the MLV replication cycle, either directly or through the inhibition of the production of a protein required for virus assembly. Can Med Assoc J, 1975 Aug 23, 113(4), 289 - 94 Acute leukemia in adults: assessment of remission induction with combination chemotherapy by clinical and cell-culture criteria; Curtis JE et al.; Remission induction was assessed by clinical and cell-culture criteria for 65 patients with acute myelogenous leukemia (AML), 11 patients with chronic myelogenous leukemia (CML) in blast crisis and 19 patients with acute lymphoblastic leukemia (ALL) . Cyclophosphamide, cytosine arabinoside and vincristine (CAV) therapy resulted in complete remission in 23 of 50 previously untreated patients with AML and in 3 of the 11 patients with CML . Fourteen patients with ALL responded to vincristine-prednisone induction therapy and two to induction therapy with CAV . The median duration of survival of the responding patients was 2.2 years, compared with 4 months for the patients who did not respond to treatment . Granulopoietic colony formation, assessed by assay of colony-forming units dependent on colony-stimulating activity in culture (CFU-C), was abnormal in 37 of 42 bone marrow aspirates from patients with AML before treatement . CFU-C concentration increased when leukocyte-conditioned medium (LCM) was added to the cultures; 13 cultures had normal or elevated CFU-C concentration with LCM . Marrow cells of patients with ALL or CML in blast crisis demonstrated a similar pattern . Serial studies of marrow CFU-C concentration of 31 patients with AML demonstrated a change to a normal pattern with successful remission induction . Results of this study suggest that administration of purified LCM to leukemic patients might increase granulocyte production from potential but unstimulated granulopoietic precursors . This therapy would lessen the probability of death from infection during remission induction. J Parasitol, 1975 Aug, 61(4), 704 - 12 Effect of pyrimethamine and sulfadiazine on the fine structure and multiplication of Toxoplasma gondii in cell cultures; Sheffield HG et al.; Rhesus monkey kidney cell cultures were inoculated with Toxoplasma gondii organisms obtained from peritoneal fluid of mice infected with the RH strain . Pyrimethamine and sulfadiazine were added either singly or in combination to the cultures 4 hr after inoculation . Twenty-four hours later the effect of the drugs on the parasites were studied by light and electron microscopy . Pyrimethamine (1.0 mug/ml) inhibited multiplication of the parasites and caused striking morphological changes . Organisms were rounded and often had a fragmented nucleus . Division was inhibited as indicated by abnormal daughter membrane formation during endodyogeny . No effect was evident in sulfadiazine-treated parasites when concentrations up to 50 mug/ml were used . However, combination of ineffective levels of pyrimethamine (0.1 mug/ml) and sulfadiazine (0.5 mug/ml) produced effects similar to those seen at a higher concentration of pyrimethamine indicating a synergistic action of the 2 drugs. Aust J Exp Biol Med Sci, 1975 Aug, 53(4), 273 - 9 The isolation of bovine ephemeral fever virus in cell cultures and evidence for autointerference; Tzipori S; Bovine ephemeral fever (BEF) virus was isolated from infected fresh cattle blood directly into Vero cell cultures . One cycle of rapid freeze-thaw destroyed the infectivity of the virus to Vero cells . The infectivity to baby mice by intracerebral inoculation, on the other hand, was only reduced . The occurrence of autointerference due to the presence of defective interfering particles in cell culture was also noted . BEF virus strain 919 was propagated to some extent in bovine kidney, testis and synovial cell monolayers, producing cytopathic effect (CPE) in 24 h . However, the CPE was nonprogressive and the addition of antinomycin D to the medium improved the virus titre only slightly. Obstet Gynecol, 1975 Aug, 46(2), 227 - 30 Viral replication in human ovarian cell culture; Harris RE et al.; A method is presented for the preparation and maintenance of human ovarian cell cultures . Sections of normal ovaries removed at surgery were minced, trypsinized, and seeded as cell cultures grown in minimal essential media at 37 C . Long-term, low-passage cultures were grown in quantities sufficient to permit viral studies . Ovarian cells, of passage 23, were challenged with 57 known viruses . Of these viruses, 52 (especially viruses of the picornavirus and adenovirus groups) produced typical cytopathic effects . The significance of these studies is discussed. Lab Anim Sci, 1975 Aug, 25(4), 420 - 4 Murine virus susceptibility of cell cultures of mouse, rat, hamster, monkey, and human origin; Reed JM et al.; Studies were initiated to determine the practicality of using various tissue cultures for the propagation of murine viruses isolated from laboratory animals . The cytopathogenic effects of 10 murine viruses known to cause disease in laboratory rodents were compared in monolayer cultures of L929, BHK-21, WI-38, BSC-1, and Vero cells . The susceptibility of primary hamster embryo, hamster kidney, mouse embryo, mouse kidney, and rat embryo cell cultures was also tested . Seven of the viruses produced effects in at least 1 of the cell substrates . The remaining 3 viruses, namely H-1, K, and mouse hepatitis, produced no effects in the cell cultures tested. J Biol Chem, 1975 Jul 25, 250(14), 5455 - 8 Expression of differentiated activities in reaggregated brain cell cultures; Seeds NW; Dissociated fetal mouse brain cells are allowed to reassociate in rotation culture to form aggregates . After several weeks these reaggregated brain cell cultures show markedly increased specific activities of monoamine oxidase, lactate dehydrogenase, and the brain-specific protein S-100, while catechol-O-methyltransferase activity increases slightly . Similar changes in these activities are found during mouse brain maturation . The amounts of monoamine oxidase, catechol-O-methyltransferase, and S-100 were also determined in surface cultures of fetal mouse brain cells, as well as glioma and neuroblastoma cell lines . The fetal brain and glial cell cultures possess much higher activities than the cultured neuroblastoma cells . However, lactate dehydrogenase activity was highest in the glioma and lowest in the surface cultures of fetal brain cells. Cell Tissue Res, 1975 Jul 23, 160(4), 431 - 42 Changes in glia-neuron relationships in cell cultures of spinal ganglia caused by puromycin; Meller K et al.; Dorsal root ganglia of chick embryos were cultured for one to four weeks on Maximow-slides . Puromycin was added to cultures for a pulse of 30' in a dose of 100 mug/ml medium . Particular interest was given to the ultrastructural features of the glia-neuron relations . Puromycin caused a shrinkage of the glial processes and consequently the continous glial envelope of the spinal ganglion neurons disappeared . These changes of glia-neuron contacts were reversible after a few days when puromycin was withdrawn from the medium . The newly formed glial sheaths around the neurons were comparable to those in untreated cultures and to those in vivo . The effects of an inhibition of protein synthesis caused by puromycin are discussed in relation to the effects on the cell motility, on the renewal of cell membranes and on the formation of cell contacts in nervous tissue. C R Acad Sci Hebd Seances Acad Sci D, 1975 Jul 21, 281(2-3), 187 - 90 {Inhibition of the incorporation of tritiated thymidine in fetal rat liver in cell culture by a fractioned liver extract}; Berneman A et al.; A dialyzed rat liver extract has been chromatographed on "Sephadex G 25" and then on "Sephadex G 50" . Thus we found a fraction which inhibits the incorporation of tritiated thymidine and stimulates the incorporation of labelled orotic acid into foetal rat liver cells in culture, but has no effect on DNA synthesis in cell lines derived from lymphocytes and fibroblasts. Experientia, 1975 Jul 15, 31(7), 844 - 6 {Induced radiation resistance in cell cultures of Chinese hamster cells: induction and manner of resistance (author's transl)}; Keusch F et al.; Mutations-induction followed by selection is a suitable method for developing a cell line with resistance to low doses of X-rays . In comparison with the original cell line, the derived resistant line is characterized by an enhanced variability of the chromosome number, and no higher level of cellular repair, limited to the two repair types described. Exp Brain Res, 1975 Jul 11, 23(1), 29 - 47 Dissociated cell cultures from fetal mouse hypothalamus . Patterns of organization and ultrastructural features; Benda P et al.; Dissociated fetal hypothalamic cells mainly taken from 14 day-old mouse fetuses were grown in vitro for increasing time (9 to 60 days) . Soon after inoculation the cells partly reaggregated and attached . The small reaggregates were then interconnected by fibers bundles . After the first week the cultures were composed of a continuous basal monolayer of flat and transparent cells, over which various types of refractile cells were lying in discontinuous areas . The ultrastructural study enabled us to identify these cell types, to describe their spatial relationships, and to follow their evolution with time in culture . The basal cell formed several superimposed layers . With increasing age, they displayed typical features of astrocytes and of ependymal cells . The latter exhibited rhythmic ciliary movements in culture . The overlying cells corresponded to three types which were associated in small clumps: primitive neuro-epithelial cells, maturing as well as mature neurons and typical neurosecretory cells . The latter cells were found as early as 9 days of culture of 14 day-old fetal hypothalamic cells and retained their typical features up to two months . Neuronal processes formed very dense networks at the surface of the cultures and terminated within the basal layers . Axon and dendrites were precociously found and were still present after two months . Within axon terminals dense-core vesicles appeared at the same time as neurosecretory cells . Synaptic vesicles and synaptic junctions were found later on. Biochim Biophys Acta, 1975 Jul 7, 395(3), 337 - 46 Properties and subunit composition of RNA polymerase II from plant cell cultures; Link G et al.; The purification of DNA-dependent RNA polymerase II (EC 2.7.7.6) from plant cell cultures of Petroselinum (parsley) is described . The procedure during which enzyme I is eliminated includes initial precipitation with (NH4)2SO4, an ultracentrifugation step, gel filtration on Sepharose 4B, chromatography on DEAE-cellulose, DNA-agarose and DEAE-Sephadex . The enzyme purified almost to homogeneity exhibits maximal activity with denatured DNA, and is activated preferentially by Mn2+; alpha-amanitin acts as a strong inhibitor . Electrophoresis of the enzyme in the presence of dodecylsulphate indicates that it is composed of seven subunits with mol . wts of 200 000, 180 000, 140 000, 43 000, 26 000, 25 000 and 16 000 . The results of molecular weight and molar ratio determinations suggest that Petroselinum RNA polymerase II may exist in two active forms differing only in the composition of their high molecular weight subunits. Vopr Virusol, 1975 Jul-Aug, (4), 403 - 6 {Effect of the synchronization of cell culture chronically infected with tick-borne encephalitis virus on the synthesis of virus antigen}; Boriskin IuS et al.; A cell culture chronically infected with tick-borne encephalitis virus was synchronized by the methods of double thymidine block and mitotic selection . There was a correlation between the time at which the cells entered the S period of the cell cycle and 4-8 fold increase in the number of cells carrying the virus antigen detectable by immunofluorescence. Tsitologiia, 1975 Jul, 17(7), 797 - 802 {Inhibition by actinomycin D of ribosomal RNA synthesis in the presynthesis period of the mitotic cycle of Chinese hamster cell cultures}; Abuladze MK; Using radioautographic technique actinomycin D at a concentration of 0.08 mug/ml was shown to inhibit selectively ribosomal RNA (rRNA) synthesis in monolayer cultures of Chinese hamster cells . The treatment with actinomycin D of cells synchronized by mitotic selection in the beginning of the G1 period causes a delay in the onset of DNA synthesis . However, a similar treatment in the late G1 period does not prevent cells from entering the S-period . The same effect has been produced by 9 mug/ml lucanthone, another inhibitor of rRNA synthesis . The experiments demonstrate a pronounced difference in cell reaction to the depression of rRNA synthesis in early and late G1 period . The data imply that the formation of rRNA, essential for the initiation of DNA synthesis, is accomplished in the first half of the G1 period, while part of rRNA has been already formed in the previous cycle. J Neurol Neurosurg Psychiatry, 1975 Jul, 38(7), 710 - 2 Recovery of adenovirus type 7 from human brain cell cultures; Lord A et al.; A strain of adenovirus type 7 was recovered from cultured brain cells, taken at necropsy from a patient aged 71 years with chronic schizophrenia . This recovery may indicate the reactivation of a latent infection with one of the few adenoviruses that has regularly-if rarely-been associated with clinical encephalitis. Proc Soc Exp Biol Med, 1975 Jul, 149(3), 587 - 91 Alkaline phosphatase modulation by osmolality changes during the growth cycle of KB cell cultures; Herz F; Growing KB cells in hyperosmolar medium causes in reduction in total alkaline phosphatase activity associated with a decrease in the proportion of the heat-labile and an increase of the heat-stable enzyme components . In standard medium enzyme activity increases progressively during a 6-day growth cycle and the proportion of heat-stable activity remains constant . In hyperosmolar medium, activity increases only during the initial 24 hr after the change in osmolality and then levels off, but the heat-stable alkaline phosphatase activity increases 7-fold within 48 hr . The transmission in thermostability is discernible 24 hr after increasing the osmolality of the medium and toward the end of a growth cycle most of the activity is heat-stable. J Gen Virol, 1975 Jul, 28(1), 59 - 72 Adaptation studies with Ross River virus: laboratory mice and cell cultures; Taylor WP et al.; Ross River virus, an Australian group A arbovirus, was adapted by serial passage to cell cultures and to day old mice . The results of titrations in mice of different ages allowed the comparison of virulence between different stocks . Passage in cell cultures depressed the virulence of virus while passage in mice raised the level of virulence . Clones of original virus populations revealed heterogeneity with respect to virulence but none of the 41 clones was as highly virulent as virus passed 10 times in mice . Clones selected in sequence during serial passage in mice indicated that adaptation proceeded by the overgrowth of variants of increasingly higher virulence, and that clones from relatively hhighly passaged s strains were still heterogeneous in virulence. Acta Virol, 1975 Jul, 19(4), 299 - 304 The mutagenic effect of measles virus on cell cultures of different origin; Mustafina AN et al.; Differences between strains of measles virus in their mutagenic effect on cells of different animals and man were found . The mutagenic activity of measles virus strains was species-specific . In the process of spontaneous transformation the sensitivity of cells to the mutagen changed. Acta Virol, 1975 Jul, 19(4), 293 - 8 Marek's disease virus (Kekava strain) replication in chickens, chick embryos and cell cultures; Yakovleva LS et al.; In the course of 12 passages of Marek's disease virus (MDV) strain Kekava (MDV-Kekava) in chickens, the morbidity varied greatly (from 23 to 50 percent) . MDV-Kekava produced plaques in cultures of chick embryo kidney and adult chicken kidney cells and chick embryo fibroblasts (CEF) . The virus adaptation to the cultures was very slow . MDV-Kekava induced the formation of pocks on the chorioallantoic membranes (CAM) of chick embryos but the proportion of embryos with CAM lesions did not exceed 24 percent . Serial passaging of the virus in chick embryos beyond the 5th passage was unsuccessful . The results of virus isolation in chickens, cell cultures and chick embryos indicate the possibility of a long-term latent virus carrier state in chickens without development of tumours. Biull Eksp Biol Med, 1975 Jul, 80(7), 93 - 5 {Protective effect of thymidine in relation to the cytostatic action of cyclic adenosine-3', 5'-monophosphate in mammalian cell cultures}; Polunovskii VA; Under the action of lmM of cyclic adenosine-3',5'-monophosphate (cAMP) the survival and the rate of reproduction of the cells of Chinese hamster in the culture decreased in comparison with control to 27 and 42%, respectively . Addition of 0.02 mM thymidine together with cAMP almost completely eliminated the cytostatic action of the latter . Thymidine also prevented the cytostatic effect of noncyclic 5'-AMR, but failed to influence the death of the cells with the action of dibutyril cAMP and theophylline . Thymidine failed to prevent the inhibitory action of cAMP on the mutant strains of mouse cells defective by thymidinekinase . A conclusion was drawn that in the concentrations under study thecytostatic action of the exogenous cAMP on the cells of mammals served as the sequence of splitting to 5'-AMP in the culture medium and was realized by blocking one of the stages of TMP synthesis. Avian Dis, 1975 Jul-Sep, 19(3), 556 - 65 Avian encephalomyelitis virus in chicken pancreatic cell cultures; Kodama H et al.; Monolayer cell cultures consisting of epithelioid cells were made from pancreatic tissue of 10-to-13-day-old chicks . The maximum virus titer of the cell-culture fluid was obtained 8 days after inoculation with an embryo-adapted avian encephalomyelitis virus (AEV) . Virus titers also increased in cell cultures inoculated with a chick-pancreas-passed AEV or a field isolant . Cell cultures inoculated with 3 strains of AEV maintained virus titers of 10(2.9)-10(3.7) 50% embryo-infective doses/ml for 15-20 days . In other cell cultures from pancreatic tissues of chicks preinfected orally with the chick-pancreas-passed AEV or the field isolant, the virus titers decreased for several days after cultivation and thereafter increased and persisted until at least the 25th or 30th day . Neither a cytopathic effect nor any inclusion body was observed in the cell cultures infected with AEV . No AEV-antigen-positive cell was detected by direct fluorescent-antibody technique. Infect Immun, 1975 Jul, 12(1), 198 - 204 Growth and cytopathology of Mycoplasma synoviae in chicken embryo cell cultures; Aldridge KE; Mycoplasma synoviae was tested for its ability to grow and induce cytopathogenic changes in chicken embryo cell cultures . M . synoviae grew to high titers by day 5 in the presence of chick cells, but showed no growth in the tissue culture medium alone even though it was enriched with nicotinamide adenine dinucleotide and swine serum . Infected chick cell cultures showed a progressive cytoplasmic degeneration on successive days of examination . Early changes involved cytoplasmic granularity and mild vacuolation . On the last day of examination the cytoplasm of most cells was completely degenerated and some showed nuclear degeneration . M . synoviae was shown to be cytophilic for the chick cell membranes where the mycoplasmas reproduced and formed microcolonies which, on successive days, increased in size . The attachment site on the chick cell membrane was shown to be neuraminidase sensitive. Infect Immun, 1975 Jul, 12(1), 148 - 55 Effect of human leukocyte interferon on vaccinia-and herpes virus-infected cell cultures and monkey corneas; Neumann-Haefelin D et al.; Pretreatment of human fibroblast cultures with human leukocyte interferon (HIF, 1,000 IU/ml) resulted in a 24-h delay of virus replication after infection with vaccinia virus and herpes simplex virus type 1 and type 2 . Additional HIF treatment 24 h after infection effectively lowered the maximum yield of viral infectivity . Equal results were obtained in simian cells with 3,000 IU of HIF per ml . The spread of two cell-bound herpesviruses, varicella zoster virus and Medical Lake macaque herpesvirus, was inhibited by 2,000 IU of HIF per ml in human fibroblasts and Vero cells, respectively . Varicella zoster virus infectivity was notably reduced by HIF, whereas the latter system showed a low sensitivity . To study the effect of HIF in the infected cornea, keratitis was induced experimentally in both eyes of 12 rhesus monkeys and 12 African green monkeys by inoculation with vaccinia virus and herpes simplex virus, respectively . In each monkey one eye served as a control for the full cycle of disease . In the other eye HIF treatment was initiated prophylactically 15 h before or simultaneously with the challenge virus infection or 6 to 20 h postinfectionally or therapeutically after onset of the disease, and the treatment was continued for 2 to 7 days . Prophylactic and simultaneous administration equally resulted in inhibition of both vaccinia and herpes keratitis . Postinfectional and therapeutic administration of interferon moderated the course of keratitis slightly and shortened the period of virus shedding. Boll Ist Sieroter Milan, 1975 Jun 26, 54(2), 82 - 9 Detection of Bhanja virus in cell cultures by fluorescent antibody technique; Lopes MC et al.; The multiplication of Bhanja virus in CV-1 cells was studied both by staining the viral antigens with the FA technique and measuring the light intensity emitted by the fluorescent cells with a photomultiplier and by the simultaneous titration of intracellular and extracellular virus . The fluorescence appeared at 3 hrs post adsorption in the form of very small granules in the cytoplasm of the infected cells . Percentage of cells containing viral antigens reached its maximum at 18 hrs post adsorption . Later on the fluorescence slowly decreased . The virus in infected cells was demonstrated 9 hrs post adsorption and maximum titre was reached 48 hrs post adsorption . The cell sheet remained apparently normal and no sign of cytopathic effect was observed until 36 hrs post adsorption. Arch Microbiol, 1975 Jun 20, 104(1), 95 - 6 Defining synchrony of cell cultures; Anagnostopoulos GD; A method was developed for the statistical analysis of growth data from synchronized growth experiments . The analysis provided a firm basis for the recognition of synchrony and the objective graphical presentation of the growth pattern of a synchronized culture . The latter could then supply reliably the parameters required for the calculation of a synchronization index, i.e . for the synchrony evaluation. Urol Res, 1975 May 30, 3(1), 13 - 20 Ultrastructural characteristics of "aging" of human prostate cells in monolayer cell culture; RiemannJF et al.; Monolayer tissue culture cells from benign nodular hyperplasia of the prostate transferred at 1-2 weeks intervals were examined under the electron microscope after the 3rd, 9th, and 10th transfers . Changes seen after 9 to 10 transfers were interpreted as an "aging process" and consisted of the presence of lysosomes of various types and variations in the mitochondria profile . These changes were described in detail and illustrated and compared to the ultrastructural appearance of monolayer cell cultures in the early transfer stage. J Neurol, 1975 Jun 9, 209(2), 103 - 14 Monocytes and histiocytes in cell cultures of cerebrospinal fluid . Morphology of cultured CSF cells; Dommasch D; A method of CSF cell culturing, based on observations of cultured cells isolated from 700 CSF specimens obtained for routine diagnostic procedures by lumbar puncture from patients who had no proven or suspected neoplastic disease, is described which enables the demonstration of proliferating mononuclear elements even when they are present in specimens with low cell count . Spread on surfaces of plastic and glass material, monocytes and histiocytes in CSF cell cultures can appear as polygonal or crescent shaped epitheloid cells, may assume spindle shapes, or transform into multinucleated giant cells . Some cells given rise to clones with different rates of proliferation, up to the formation of a monolayer . After short term culturing the cytochemical characteristics of the cells are comparable to those of the native cells . Phagocytosis in culture is possible . Cells with a high rate of proliferation can be isolated from CSF specimens in subacute non-bacterial inflammatory processes, in chronic meningitis, in the state of repair of bacterial meningitis and subarachnoid hemorrhage, after repeated lumbar punctures and other unspecific irritations such as myelography and pneumencephalography, and in the course of intrathecal cytostatic therapy. Brain Res, 1975 Jun 6, 90(1), 1 - 21 Neurons from fetal rat brain in a new cell culture system: a multidisciplinary analysis; Godfrey EW et al.; A new culture system for cells from the mammalian brain was developed by a modification of a previously established technique . This modification involved the use of fluorodeoxyuridine and adult horse serum . The cultures contained large, easily visualized neurons both isolated from other neurons and in networks of varying complexity . These cells were large enough to permit reliable intracellular electrophysiologic recording and were often sufficiently dispersed to allow examination of membrane responses to iontophoretically applied neurotransmitter candidates . Many responses characteristic of central neurons in situ were seen, including evoked and spontaneous action potentials, complex patterns of inhibitory and excitatory post-synaptic potentials, and neurotransmitter-induced membrane responses . These preparations were examined by phase contrast microscopy, by light microscopy after silver impregnation and by Nomarski interference optics . Total choline acetyltransferase (CAT) activity was little changed and specific activity was increased in the new culture system as compared with the earilier system . Conditions which gave the highest specific activity of CAT also provided the best cultures from the standpoint of electrophysiologic and morphologic analysis . This new approach will allow, in culture, detailed multidisciplinary analyses of individual neurons and small networks of neurons from the mammalian brain. Zh Mikrobiol Epidemiol Immunobiol, 1975 Jun, (6), 35 - 8 {Conditions of development of a secondary immune response in guinea pig lymphoid cell cultures}; Pinegin BV; On addition of a specific antigen to the cell culture of the lymph nodes of the immunized guinea pigs there was seen an intensification of the synthesis of the DNA and of the antibody formation . Both processes occurred more intensively in incubation of cells on a medium with an addition of rabbit antiserum to the guinea pig erythrocytes than on a medium with a normal homologous serum . It is supposed that the optimal conditions for the initiation of antibody formation in the lymphoid cells were created in case of a combined action of a specific antigen-inductor and a nonspecific stimulant intensifying the DNA synthesis. Proc Soc Exp Biol Med, 1975 Jun, 149(2), 427 - 32 Adaptation of Mycoplasma hominis to an obligate parasitic existence in monkey kidney cell culture (BSC-1); Furness G et al.; During attempts to eliminate Mycoplasma hominis from a monkey kidney BSC-1 cell line with antibiotics, the mycoplasmas were isolated repeatedly . However, the organisms ultimately failed to grow on medium although electron microscopy confirmed that the cell culture still contained mycoplasmas . Thus, the mycoplasma had adapted to an environment in which viable cells were required for growth . Budding mycoplasmas which are indicative of replication were seen associated with viable cells extracellularly . Moreover, structures resembling cycoplasmas were observed budding from the cells which suggests that the mycoplasmas replicate within the cells and are similar to many viruses in their manner of release from the cells. J Comp Neurol, 1975 Jun 1, 161(3), 295 - 306 Human brain in tissue culture . I . Acquisition, initial processing, and establishment of brain cell cultures; Gilden DH et al.; This paper details the in vitro techniques used to establish cells in culture from the brains of 40 patients, most of whom had chronic neurologic disease . The clinical and pathologic features of these patients are given . The success in establihsing cell lines was dependent upon the origin of tissue (biopsy vs . autopsy), the site of removal from the brain, and various environmental and technical manipulations in vitro. Arch Exp Veterinarmed, 1975 Jun, 29(3), 441 - 57 {Electron microscopy studies on the proliferation of foot-and-mouth disease virus in cell cultures . III . Morphogenesis in cytoplasm}; Schulze P et al.; The previous parts have been concerned with the participation of the cell nucleus in the formation of the RNA of FMD virus . However, the actual morphogenesis of the virus takes place in cytoplasm . In BHK cells, changes attributable to virus infection were visible by the second hour, with the formation of threads and large polysome complexes near the nucleus . Viral particles soon appeared between these structures . There were no pronounced foci of viroplasma, and it seemed that they were not necessary . Simultaneously new membranes formed in the cell . Clumps of viral particles were next visible in the cxtoplasma . The clumps became enveloped and were transported in this way to the periphery of the cell . Elsewhere there was uptake of particles in autophagic vacuoles, an expression of cellular defensive processes . In ultra-thin sections the virions measured 21-25 nm . Within vacuoles the inner part of the virus, the nucleoid, showed greater contrast than the periphery, the capsid . At first there were only slight changes in mitochondria . Liberation of virus by cell rupture occurred only after severe damage to the cell, particularly the lysosome membranes. Arch Exp Veterinarmed, 1975 Jun, 29(3), 427 - 39 {Electron microscopy studies on the proliferation of foot-and-mouth disease virus in cell cultures . II . Changes in nucleic acid metabolism of the cell nucleus}; Schulze P et al.; BHK cells were infected with FMD virus and treated with tritium-labelled thymidine and uridine for examination by autoradiography under the electron microscope . Labelling of the DNA, examined by autoradiography under the optical microscope, showed inhibition of 3H-thymidine incorporation . For demonstrating RNA labelling of nuclei, some cells were treated with actinomycin D and others were left untreated . Under the lectron microscope there was no evidence of increased 3H-uridine incorporation in the untreated cells after virus infection, but actinomycin treatment increased RNA labelling in extranucleolar parts of the nucleus, evidently RNA synthesis independent of DNA . There was evidence of some synthesis of virus-specific RNA in the nuclei . The extent of virus-specific RNA synthesis in the cytoplasm was less extensive than in the nucleus. Arch Exp Veterinarmed, 1975 Jun, 29(3), 411 - 25 {Electron microscopy studies on proliferation of foot-and-mouth disease virus in cell cultures . I . Morphologic changes in cell nucleus}; Schulze P et al.; The first morphological indication of FMD infection of a cell culture was in the nucleus . Components of nucleoli became segregated and were finally present only as remnants . It was not possible to distinguish different stages of segregation, as in the case of entero-virus infections, because of the rapidity of FMD virus proliferation . Following changes in nucleoli there was margination of chromatin . Particularly striking was an increase in interchromatin granules . Changes in the nuclear membrane seemed to facilitate the transfer of nuclear material to the cytoplasm . Strongly pronounced dilatation of the peri-nuclear cleft, like that seen in aphthae and other tissues, were rarely visible in infected cell cultures. Neurobiology, 1975 Jun, 5(3), 192 - 6 Morphological changes of astrocyte-like cells induced by serum beta-lipoprotein in brain cell culture; Offner H et al.; When added to brain cell cultures of newborn rats, serum and, in particular, its beta-lipoprotein fraction caused significant morphological transformations of astrocyte-like cells present in the culture . The changes were instantaneous as they appeared within 1 min after addition of beta-lipoprotein and they were characterized by swelling and loss of cellular processes of all astrocyte-like cells present . The lipoprotein effect was reversed after a period of about 7 h . Since the blood-brain and blood-spinal fluid barrier in multiple sclerosis is decreased towards serum macromolecules, i.e . the serum beta-lipoprotein, this protein may enter the central nervous system and thereby initiate a demyelinating process. Proc Soc Exp Biol Med, 1975 Jun, 149(2), 439 - 42 Role of bovine albumin in a serum-free suspension cell culture medium; Yamane I et al.; A serum-free culture medium, supplemented with 1% bovine serum albumin, supported the growth of both primary and continuous suspension-type cultures of various mammalian tumor cells . The role of albumin added to the medium was also studied . Defatted albumin failed to support cell growth, unless reconstituted with its lipid extract . Similarly, defatted albumin when combined with oleic and linoleic acids, also supported cell growth . Therefore, albumin-bound fatty acids play an important growth-promoting role in serum-free medium. J Gen Virol, 1975 Jun, 27(3), 267 - 74 Replication of reticuloendotheliosis viruses in cell culture: chronic infection; Temin HM et al.; After an initial acute infection with cell killing, chicken or duck embryo fibroblasts infected in culture with reticuloendotheliosis viruses set up a chronic infection with no cell killing or morphological transformation . Essentially all of the chronically infected cells produced virus . The virus production was not sensitive to cytosine arabinoside or mitomycin C as was virus production in an acute infection . The chronically infected cells had a strong group-specific resistancto the c.p.e . of superinfecting reticuloendotheliosis viruses . However, they were sensitive to vesicular stomatitis virus and avian leukosis-sarcoma viruses . After double infection, single cells produced reticuloendotheliosis virus and avian leukosis-sarcoma virus. C R Acad Sci Hebd Seances Acad Sci D, 1975 May 21, 280(19), 2273 - 5 {Development and pathogenesis of an entomopoxvirus in lepidoptera cell culture}; Quiot JM et al.; Cell cultures of Lymantria dispar (Lepidoptera) have been successfully infected with the Entomopoxvirus of Amsacta Moorei (Lepidoptera) . The different steps of viral morphogenesis and pathogenesis have been precisely detailed by light and electron microscopy of infected cells. Zentralbl Bakteriol {Orig A}, 1975 May, 231(4), 508 - 13 Drying and irradiation of calf and horse serum . I . Influence on the growth of cell cultures and mycoplasmas; Veber P et al.; Gamma-irradiation of liquid and dried calf sera with 2.5 Mrads did not affect their capacity to promote the growth of chick embryo, L cell and human embryonic lung cell cultures . Drying and gamma-irradiation of horsesera did not affect their capacity to support the growth of 3 mycoplasma of the species Acholeplasma laidawii and Mycoplasma bovigenitalium. Isr J Med Sci, 1975 May, 11(5), 476 - 81 Chromosomal mosaicism in amniotic cell culture . A diagnostic Dilemma; Kohn G et al.; Chromosomal mosaicism, with supernumerary C or C group elements, was observed in the cultured amniotic fluid cells of four fetuses undergoing prenatal diagnosis . There were discrepancies in the karyotypes of cells from different culture flasts of a single fluid sample, between cultures from successive uterine aspirations, and between cultures of amniotic fluid and fetal tissues obtained by pregnancy interruption . Most alarming was the finding, in one case, of identical mosaicism in different culture flasks as well as in repeated amniocenteses derived from a phenytypically normal fetus . In each instance, the aborted fetus or newborn infant proved to be phenotypically and cytogenetically normal . This suggests that mosaicism, demonstrated in cultured amniotic fluid cells, may not reflect the chromosomal constitution of the fetus and may pose a dilemma regarding an accurate diagnosis. J Med Chem, 1975 May, 18(5), 457 - 60 Porphyria-inducing activity of a series of pyridine and dihydropyridine compounds . Investigation in a cell culture system; Roomi MW; A series of analogs of 3,5-diethoxycarbonyl-1,4-dihydro-2,4,6-trimethylpyridine (DDC)was prepared and tested for porphyria-inducing activity in chick embryo liver cells . One of the analogs tested, viz.3,5-di-tert-butoxycarbonyl-1,4-dihydro-2,6-dimethylpyridine, was found to be highly active despite the absence of a 4-alkyl substituent . It was concluded that tert-butoxycarbonyl groups are resistant to enzymic hydrolysis and that compounds containing such groups are resistant to inactivation by chick embryo liver cells . Several analogs of DDC were found with considerably higher activity . These should be useful in inducing high levels of beta-aminolevulinic acid synthetase prior to undertaking the isolation of the enzyme. Clin Genet, 1975 May-Jun, 7(5), 400 - 4 Chromosomal mosaicism in amniotic fluid cell cultures; Sutherland GR et al.; Six cases of chromosomal mosaicism detected in amniotic fluid cultures are described . In five of these there was no evidence of fetal mosaicism . In one case fetal mosaicism was demonstrated but only by the study of fibroblasts since blood cultures showed only normal cells . The implications of amniotic fluid mosaicism are discussed and it is concluded that this usually does not indicate fetal mosaicism . The value of repeated amniocentesis in the diagnosis of fetal mosaicism was demonstrated by findings in three of the cases . It is recommended that amniotic fluid cultures be harvested in situ for chromosome studies and that cytogenetic results be expressed as number of colonies karyotyped rather than as number of cells analyzed. Biofizika, 1975 May-Jun, 20(3), 349 - 53 {Kinetic regularities of RNA synthesis . VI . Reverse problem of RNA accumulation in synchronous cell cultures}; Tsarev OB et al.; An algorithm is presented for determining relative nucleotide composition and rates of synthesis of some RNA fractions according to the experimental data of the change with time of mean nucleotide composition of the mixture of RNA fractions of synchroneous cell culture . Piece-linear models with voluntary number of fractures are taken as the models of accumulation of separate RNA types. Am J Vet Res, 1975 May, 36(5), 635 - 40 Propagation of Anaplasma marginale in bovine lymph node cell culture; Hidalgo RJ; Anaplasma marginale was propagated in cell cultures derived from bovine lymph node (LN) . Treatment of host cells with diethylaminoethyl dextran (DEAE-D) before inoculation and centrifugation of inoculum onto the monolayers resulted in significant numerical increases of A marginale . The direct fluorescent antibody technique (FAT) was used for detection of the organism in culture . The rat was combined with the standard microscopic count procedure to obtain numerical estimates of the organism in cell culture . Infection of LN cells was irregular, with some cells containing many organisms and others containing none . The organisms were dispersed or in inclusions in the cytoplasm of LN cells . Numerical increases of organisms occurred within 6 hours and these were greatest at 12 to 24 hours . After 24 hours, the organisms decreased rapidly, but small numbers of them were observed for at least 7 days . The average generation time in culture was approximately 17.1 hours. Shika Rikogaku Zasshi, 1975 May, 16(35), 87 - 109 {Studies on the cytotoxic action of various composite resins by means of cell culture (author's transl)}; Nishida T; In order to investigate biocompatibility of composite resin, L strain cells were brought contact either directly with mixed resin or with immersion liquid, which was obtained by replacing with fresh medium twice for 48 hours, followed by utilizing these immersed medium as the second immersion liquid or the third, and results were assessed by cell multiplication rate calculated from cell nuclei counting per milliliter of medium, morphological observation and agar diffusion method, originally used by Guess et al . (1965) and later modified . The materials used were selected from the presently available composite resins, which were classified by composition and form for use provided by manufacturers, i . e, powder, paste, or liquid . Those which were classified were as follows; Types Pa-L-L (Paste-Liquid-Liquid), Pa-L (Paste-Liquid), Pa-Pa (Paste-Paste), Po-L (Powder-Liquid) and Po-L-Pa (Powder-Liquid-Paste). Proc Natl Acad Sci U S A, 1975 May, 72(5), 1955 - 9 Formation of cholinergic synapses between dissociated sympathetic neurons and skeletal myotubes of the rat in cell culture; Nurse CA et al.; Sympathetic principal neurons, dissociated from superior cervical ganglia of newborn rats, were plated into cultures containing rat skeletal myotubes formed from previously plated primary myoblasts . Electrophysiological evidence is presented that the neurons developed cholinergic synapses with the myotubes . In addition, the neurons developed cholinergic synapses with each other as previously reported {O'Lague et al . (1974) Proc . Nat . Acad . Sci . USA 71, 3602-3606} . The acetylcholine receptors of myotubes differed from those of the neurons in their sensitivities to curare and hexamethonium, in a manner expected of adult muscle and ganglionic receptors . alpha-Bungarotoxin blocked synaptic transmission from neuron to myotube, but not from neuron to neuron in the same culture. In Vitro, 1975 May-Jun, 11(3), 117 - 29 Carcinogenesis in vitro . II . Chemical transformation of diploid human cell cultures: A rare event; Igel HJ et al.; Seventy-five diploid human cell s-rains were subjected to a number of chemical carcinogens, including urethane and polycyclic hydrocarbons . In most cases, no visible morphological alterations were induced by any treatment . Development of morphologically altered foci was noticed in urethane-treated cultures derived from a patient with von Recklinghausen's disease . This disease is transmitted by an autosomal dominant gene, and has a high rate of spontaneous transformation of neurofibromas to neurofibrosarcomas . Attempts to isolate continuous cell lines from altered foci were successful in only two of several attempts . These continuous cell lines demonstrate altered morphology, loss of contact inhibition, accelerated growth rate, and have attained over 240 generations in a period of 140 weeks . Untreated control cultures became terminal by the 20th generation . Giemsa banding procedures showed that the chromosomal complement consisted of heteroploid human chromosomes . A second diploid cell strain derived from the above patient's sibling, also suffering from von Recklinghausen's disease, likewise was morphologically altered by urethane . Chemical transformation of human cells is difficult to induce; however, selection of genetically predisposed cells and prolonged, intermittent, and repeated chemical treatment may be important factors in achieving transformation. In Vitro, 1975 May-Jun, 11(3), 130 - 41 Use of epithelial cell cultures for studies on the mechanism of transformation by chemical carcinogens; Weinstein IB et al.; Evidence is reviewed for and against four major theories of chemical carcinogenesis . The development of several normal and transformed epithelial cell lines which should be useful for the analysis of this problem is described . The detection of RNA viral particles in cells transformed with chemical carcinogens is a recurrent finding in studies from our own and other laboratories, but the significance of these particles in terms of the mechanism of chemical carcinogenesis remains to be determined . Finally, we have described the first mutants of chemically transformed epithelial cells which are temperature sensitive in the maintenance of the transformed phenotype . These mutants should be particularly useful for detecting the critical biochemical changes that distinguish a chemically induced tumor cell from its normal counterpart. Proc Soc Exp Biol Med, 1975 May, 149(1), 238 - 41 Follicle stimulating hormone stimulation of 125-I-human chorionic gonadotropin binding in porcine granulosa cell cultures; Channing CP; In order to see if FSH acts directly upon the granulosa cell to stimulate hCG binding, granulosa cells harvested from small 1-2 mm porcine follicles were grown in 250 ml flasks in chemically defined media containing 0.05 mug/ml highly purified human FSH for 2, 4, and 6 days . The defined medium consisted of culture medium 199 plus 0.4% bovine serum albumin, 0.2% lactalbumin hydrolysate and 10 munit/ml insulin . The cultures were harvested by scraping with a rubber policeman and incubated with 0.1 mug/ml 131-I- or 125-I-hCG . Binding expressed as cpm/culture or per mg protein yielded similar results . In five separate experiments addition of FSH stimulated hCG binding two- to fourfold above control cultures . In a typical experiment after 2 days of culture, the specific binding of control cultures to hCG was 962 plus or minus 45 cpm/culture (-x plus or minus SE; n = 3) and the binding in cultures grown in the presence of 0.05 mug/ml FSH was 3933 plus or minus 1787 (n = 3; P less than 0.01) . Granulosa cells harvested from large (8-12 mm) follicles grown under similar conditions bound 29,669 plus or minus 948 cpm/culture (n = 4) . These data demonstrate that FSH may have a direct stimulatory role upon induction of granulosa cell LH-hCG receptors in vitro. Cell, 1975 May, 5(1), 37 - 42 A model of cell cycle control: effects of thymidine on synchronous cell cultures; Thomas DB et al.; Further evidence is presented in support of a model for growth control in which commitment for cell division is determined by an event in the preceding cell cycle . A study was made of conditions affecting synchronous growth following treatment of murine mastocytoma cells with excess thymidine at different phases of the cell cycle . Cells were synchronized by a physical procedure involving velocity sedimentation in a zonal rotor . Pulse treatment of such cultures with thymidine at times corresponding to the S, G2, and M periods had no effect on further growth . However, addition at G1, although having no immediate effect, arrested cell growth in the next cell cycle . This temporal effect may account for the decay of synchrony observed during double thymidine blockade or thymidine-FUdR blockade . When the time interval between two such blocks was 7 hr or less, P815Y cells were arrested after one synchronous division . At this critical time a majority of cells were at, or near, G1 . It is suggested that thymidine exerts a hitherto unrecognized effect at the G1 interval. Acta Virol, 1975 May, 19(3), 250 - 4 Use of polyethylene glycol-treated calf serum for cell cultures in virus and interferon studies; Inglot AD et al.; Immunoglobulins and lipoproteins can be efficiently removed from calf serum by precipitation with polyethylene glycol (PEG) 6000 under sterile conditions . The PEG-treated serum is suitable for cell cultures used for virus growth and assays . Moreover, PEG was found to slow down the growth of L cells and to enhance the production and activity of mouse interferon. C R Acad Sci Hebd Seances Acad Sci D, 1975 Apr 21, 280(15), 1793 - 5 {Growth of Sarcocystis tenella in cell culture}; Dubremetz JF et al.; Sarcocystis tenella endozoites obtained from sheep oesophagus cysts have been cultivated in embryonic sheep kidney cells . They quickly enter the cells, become shorter and wider ("stage 2"), then grow to an ovoid shape within 24 h ("stage 3"). Nippon Yakurigaku Zasshi, 1975 Apr, 71(3), 301 - 5 {Effects of drugs on cell culture (II)}; Mukaide A et al.; The toxicity of drugs was determined using embryonic skin and muscle from humans (Flow 1,000) . The dosage causing a 50% inhibition culture growth (ID50) and minimum concentration, caused by the detachment of the cell from the vessel wall, were determined . ID50 values of ibuprofen, naproxen, Y-5554, dichlofenac and aminopyrine were found to be 150, 320,220, 110 and greater 500 mug/ml respectively . Minimum concentration, caused by the detachment of the from the vessel wall, was as follows: ibuprofen 250, naproxen 250-500, Y-5554 250-500, dichlofenac 62.50-125 and aminopyrine 1,000-2,000 mug/ml respectively. Nippon Yakurigaku Zasshi, 1975 Apr, 71(3), 295 - 300 {Effects of drugs on cell culture (I)} {Insensitivity of stationary cultures of transformed mouse fibroblasts to agents stimulating DNA synthesis in normal cell cultures} Vasil'ev IuM, Gel'fand IM, Pletiushkina OIu, Fetisova EK. Stationary cultures of the mouse transformed cells L and S-40 sensitive to topoinhibition were found to be insensitive to the action of hyaluronidase, RNAase, and colcemid in doses known to stimulate multiplication of normal mouse fibroblasts . These cultures were still insensitive to the action of medium change and removal of a part of the monolayer. J Gen Virol, 1975 Apr, 27(1), 107 - 10 The effect of interferon inducers on colony stimulating factor production in L cell cultures; Havredaki M et al.; Bone marrow colony-stimulating activity in the culture media of L cell mono-layers treated with Newcastle disease virus or polyriboinosinic:polyribocytidylic acid showed an early increase followed by a marked fall fo activity when compared with non-induced cultures. Am J Vet Res, 1975 Apr, 36(4 Pt.1), 407 - 12 Propagation of bovine viral diarrhea viruses in bovine fetal lung cell cultures; Goldsmit L et al.; A procedure to prepare and maintain bovine fetal lung (BFL) cell cultures was established . These cell cultures grew abundantly and readily and were easy to handle . Monolayers could be kept in satisfactory condition in maintenance medium for 14 days . The yield from the lungs of one fetus was 15 to 30 primary culture Roux bottles, and 40,000 5th-generation test tubes . The BFL cells were satisfactorily kept at minus 70 C with the addition of dimethyl sulfoxide (DMSO) . When the BFL cell cultures were infected with cytopathic bovine viral diarrhea (BVD) viral strains, the cytopathic effect (CPE) was clear and distinct and was first seen on postinoculation (PI) day 1 . The end points for viral titrations and serum-neutralization (SN) tests were readily determined . The BFL cells were satisfactory for supporting replication of the BVD viral strains . The titer of the virus propagated in the cells was 10-7.0 to 10-8.0 median tissue culture infective doses (TCID50)/1ML . Growth curves of the BVD viruses are reported. Pathol Biol (Paris), 1975 Apr, 23(4), 333 - 8 {Use of the plastic "Terphane" for the maintenance and the study of cell cultures}; Gueguen C et al.; Terphane plastic used as substrate for tissue culture, facilitates both cytochemcial, biochemical and ulstratructural studies of cells in situ . Particularly pliable, thin and resistant, the sheet of Terphane plastic is held tense by a system of two plaques of Petri dish type . This apparatus is perfectly waterproof, sterilisable and may be used indefinitely . Growth, morphology, ultrastructure and enzyme activities of primary or subcultures of rat and human liver maintained on terphane plastic are comparable with those of cells cultivated on Falcon polystyrene . Furthermore, terphane offers several advantages over the Melinex plastic: its thinness, resistance and plasticity render easy all manipulations. Tsitologiia, 1975 Apr, 17(4), 458 - 63 {Cytogenetic characteristics of suckling mouse brain cell cultures, chronically infected with Japanese encephalitis virus}; Mikhailova GR et al.; The brain cells of the suckling mice line MSB-1-K-33 chronically infected by an attenuated variant of the Japanese encephalitis virus and of cell clones isolated from the later, had mainly a neartetraploid keryotype (the modal class 70-71 chromosomes) . In metaphases of cloned cell populations, an increase of number of the chromosomes was especially obvious in clones 3 and 4 (modal classes in both cases were 76-77 chromosomes) . Cell population of clone 1 differed insignificantly from that of the parental line MSB-1-K-33 in respect of its cytogenetic characteristics . In metaphases of the line MSB-1-K-33 and clones 1, 3, and 4, a high frequency of chromosomal damages was observed . The most frequent type of structural chromosome aberrations were chromatid breaks . The karyotypes of clones 3 and 4 were characterized by presence of a large marker metacentric chromosome in 50-53% of the cells . The data obtained suggest a continuous effect of the Japanese encephalitis virus on the karyotype of cells in infected culture. Infect Immun, 1975 Apr, 11(4), 698 - 703 Neutralization of Chlamydia trachomatis in cell culture; Howard LV; Neutralization of Chlamydia trachomatis was assayed by the decrease in inclusion-forming units in baby hamster kidney cells grown in culture . Five percent fresh guinea pig sera increased neutralization titers of rabbit antisera 100- to 1,000-fold but had no effect when normal rabbit sera were tested . Neutralization of a type A or B trachoma isolate was strain specific . Neutralization by human eye secretions and sera also was demonstrated when guinea pig sera were included in the test . All of the six human sera tested showed strain specificity against types A or B, in agreement with typing by the fluorescent antibody technique. Aust J Biol Sci, 1975 Apr, 28(2), 109 - 14 Osmotic effects of sorbitol accumulation in monkey kidney epithelial cell cultures; Hutton JC et al.; It has been observed that primary monolayer cell cultures derived from monkey kidney cortex behave in a similar manner to the mammalian lens in that they accumulate high concentrations of sorbitol when they are incubated in medium containing a high glucose concentration (33 mM) . An investigation was undertaken to determine whether the accumulation of sorbitol by these cultures results in cellular damage by an osmotic mechanism similar to that which has been proposed to occur in the lens . Phase-contrast microscopy and histochemical investigations revealed that no changes in the cell size, cell growth rate, or cell staining properties occurred as a result of exposure of the cell cultures to a glucose concentration of 33mM for up to 4 days . The cell protein and myo-inositol concentrations and fatty acid composition were also unaffected, as was the incorporation of radioactivity from {U-14C}leucine into cell protein . The rate of 86Rb influx of the cell cultures was decreased and the rate of 86Rb efflux was increased by incubation in medium containing a glucose concentration of 33 mM . Frome these observations it was concluded that the accumulation of sorbitol by monkey kidney epithelial cell cultures did not exert a pathabolic influence upon their growth and metabolism, and that these cells, unlike the lens, have the capacity to compensate adequately for changes in transmembrane osmotic gradients induced by sorbitol accumulation. Acta Pathol Microbiol Scand {B}, 1975 Apr, 83(2), 71 - 8 Studies on the growth of feline panleukopaenia virus in cell cultures; Flagstad A; The growth of feline panleukopaenia virus was examined in relation to various cell growth curves of secondary feline kidney cells . In cell cultures with a high mitotic index, the manifestation of virus infection, expressed as percentage number of cells with inclusion bodies, was correspondingly high . In cultures with low mitotic index, the percentage number of cells with inclusion bodies was low . A cytopathic effect was seen by inoculation of virus with a titre of 10-3-5TCID-50/ML . This effect was most pronounced using cell cultures seeded in a quantity of 1 million cells per ml to 500,000 cells per ml with inoculation made during the first 24 hours after seeding when the mitotic index was high . Both the cytopathic effect and the occurrence of inclusion bodies were of transient nature . The peak of infection, both with regard to the cytopathic effect and the percentage number of cells with inclusion bodies, was seen three days after inoculation. Proc Natl Acad Sci U S A, 1975 Apr, 72(4), 1584 - 8 Induction of growth in resting fibroblastic cell cultures by Ca++; Dulbecco R et al.; Of all the components of the culture medium, only CaCl2 induces DNA replication when added to resting cultures of Balb/c 3T3 cells . The effect is present even in a serum-free medium . Increasing the Ca++ concentration above the standard 1.8 mM in the medium of a new culture increases the total number of cells ultimately produced, without affecting the initial cell growth rate . This effect is synergistic with that of serum . The elevated Ca++ concentration also induces striking morphological changes . The Ca++ effect could not be reproduced by a Ca++ ionophore . These observations afford a new tool for studying how the various intracellular events following the addition of growth factors to resting cultures are involved in the control of cellular growth. Infect Immun, 1975 Apr, 11(4), 770 - 82 Bovine parainfluenza type 3 virus infection: virus replication in bovine embryonic cell cultures and virion separation by rate-zonal centrifugation; Tsai KS et al.; Replicative sequences of a bovine strain of parainfluenza type 3 virus in bovine embryonic kidney and spleen cell cultures were investigated by light and fluorescence microscopy and by ultrathin section and negative-contrast electron microscopy . Observations from light and fluorescence microscopy showed that intracytoplasmic inclusions were detected as small granules surrounding the nuclei of more than 90 percent of the cell population by day 2 postinoculation . With the increase of postexposure times, these inclusions coalesced into larger bodies which occupied large portions of the cell . Ultrastructurally, the first sign of virus development was the appearance of aggregates of viral nucleocapsids in the vicinity of the nucleus . With the concomitant accumulation of viral nucleocapsids in the cytoplasm, the virus maturation was expressed by budding processes through the cell membrane into round, oval, or elongated forms . Eosinophilic inclusions were demonstrable in many mitotic cells . Ultrastructurally, these cells were observed to produce virus particles by a process identical to that of resting cells . Virions, prepared from infected culture fluid and negatively stained, appeared to be pleomorphic and their diameter ranged from 200 to 600 mm . The virions were separated, by rate-zonal centrifugation, into two subclasses in a sucrose gradient (15 to 60 percent, wt/wt) . The slowly sedimenting virions had a density approximately 1.20 gm/cm3 and an average size of 200 nm in diameter, whereas the faster-sedimenting virions had a density of 1.24 gm/cm3 and average diameter of 400 nm. J Infect Dis, 1975 Apr, 131(4), 452 - 5 Differential action of deoxynucleosides on mammalian cell cultures infected with herpes simplex virus types 1 and 2; Kelman AD et al.; Cytopathic effects induced by eight serologically defined isolates of herpes simplex virus type 2 (tested on human amnion cells) were markedly inhibited by thymidine at a concentration of 5 mM; eight serologically defined isolates of herpes simplex virus type 1, however, were not significantly inhibited . A similar effect was seen with thymidine, deoxyguanosine, and deoxycytidine at 1-mM concentrations in tests with rabbit kidney cultures . The inhibitory effect of thymidine was not blocked by the simultaneous presence of deoxycytidine, which has been shown by others to release mammalian cells from thymidine suppression . Differential suppression of herpes simplex cytopathic effects by these deoxynucleosides provides further evidence of biochemical differences between herpes simplex types 1 and 2 . This phenomenon offers a basis for rapid differentiation of type 1 from type 2. Tsitologiia, 1975 Apr, 17(4), 470 - 2 {Localization of the fluorescent portion of the Y-chromosome in interphase nulcei of human embryonic kidney cell cultures}; Ganin AF et al.; The localization and frequency of accurrence of Y-chromosome fluorescent bodies in interphase nuclei in the cellular culture of 4-months male and female human embryos, were studied with fluorochromine method with quinacrine dehydrochloride . In cellular cultures of male embryonic kidney the frequency of Y-chromatin was about 50% . The Y-chromosome structural connection with nuclear membrane and nucleolus was demonstrated. Science, 1975 Mar 7, 187(4179), 847 - 9 Beta cell culture on synthetic capillaries: an artificial endocrine pancreas; Chick WL et al.; Beta cells from neonatal rats were cultured on bundles of artificial capillaries perfused with tissue culture medium . Cells continued to release insulin and remained responsive to changes in glucose concentration . The quantity of insulin released was similar to that of conventional flask cultures. Br J Dermatol, 1975 Mar, 92(3), 305 - 9 Primary cell culture for biochemical studies of human keratinocytes . A method for production of very large numbers of cells without the necessity of subculturing techniques; Flaxman BA et al.; Starting with large numbers of small split-thickness explants of human skin, it is possible to grow ample numbers of keratinocytes in vitro as primary cell cultures to permit biochemical studies without the need of subculturing techniques. Br J Cancer, 1975 Mar, 31(3), 329 - 37 Spontaneous and chemically induced transformation of rat embryo cell cultures; Kirkland DJ et al.; The transformation of Wistar rat embryo cells in vitro has been studied in passaged cultures using two criteria for transformation: (1) the ability of cells to form colonies in soft agar and (2) the ability of cells to form tumours in young syngeneic animals . In general there was good correlation between the two criteria . Spontaneous transformation was observed in all untreated cultures by 44 weeks although, by not allowing the cells to become confluent, the tendency was for cultures to transform earlier (i.e . 15-21 weeks) . It was noticeable that despite untreated cultures having been in vitro for different lengths of time, most cultures transformed after a similar number of passages (42-50) . Treatment of the embryo cells with the alkylating agent nitrosomethylurea (NMU) or benzo(alpha)pyrene (BP) sometimes resulted in transformation after a shorter period in vitro than the controls (minimum 12 weeks) although some treated cultures took longer . Transformed cells produced transplantable fibrosarcomata in syngeneic hosts and those arising from NMU transformed cells were histologically different from those arising from spontaneously transformed cells . The significant of spontaneous transformation in in vitro rat cell transformation systems is discussed. In Vitro, 1975 Mar-Apr, 11(2), 69 - 77 Physiological and biochemical effects of the mycotoxin patulin on Chang liver cell cultures; Schaeffer WI et al.; Patulin exhibits both cytotoxic and cytopathic effects on cultured Chang liver cells . The LD50 found was 1.85 mug per ml of patulin . Effects on growth were observed with as little as 0.1 mug per ml of patulin; a 50% reduction in growth was observed at 0.38 mug per ml of patulin . Using a challenge dose of 2.5 mug per ml of patulin, the cytotoxic effect was reversible after an exposure of 10 min, but was not reversible after 20 min . Protein synthesis was depressed after 60 min and RNA synthesis after 20 min of contact with patulin . Neither protein nor RNA synthesis was completely inhibited after 260 min. Endocrinology, 1975 Mar, 96(3), 637 - 43 Pancreatic beta cell culture: preparation of purified monolayers; Chick WL et al.; Procedures were developed for preparing partially purified beta cell monolayer cultures . Neonatal rat pancreases were dissociated with a trypsin-collagenase solution . Beta cells were separated from denser acinar cells by centrifuging the initial suspension in a two layer discontinous Ficoll gradient (20, 25%) . Resultant cultures, highly enriched in beta cells, were further purified by incubation with cystine-free medium . This caused necrosis of the majority of fibroblastoid cells within two days, while beta cells were considerably less affected . The resultant cultures contained an average of 72% beta cells compared to 10% in untreated control cultures . Insulin release by purified monolayers remained responsive to changes in the glucose concentration of the culture medium. Vopr Virusol, 1975 Mar-Apr, (2), 235 - 8 {Chronic infection of VERO cell cultures with Japanese encephalitis virus . 2 . Certain characteristics of variability of persistent viruses}; Deriabin PG et al.; Japanese encephalitis virus contained in the medium of chronically infected VERO-K43 cell cultures was shown to be sensitive to the effect of RNA-ase, resistant to treatment with urea, to have no hemagglutinating activity . After 2 passages in suckling mouse brain the virus lost its sensitivity to RNA-ase, was inactivated by urea, and its hemagglutinating activity was restored . The importance of Japanese encephalitis virus variability in the mechanism of chronic infection of cell cultures is discussed. Tsitologiia, 1975 Mar, 17(3), 332 - 6 {Cytomorphological characteristics of continous lymphoid cell culture invaded by Theileria}; Golobova MT et al.; Cell types and morphological characteristics of Theileria annulate-invaded cell lines from spleen, thymus, and lymph nodes were studied . Parasites in the form of macroschizonts were shown to invade three main cell groups: small lymphocyte type, monocyte type, and large reticulum cell type . Theilerias were found in the cytoplasm of these cells . Fibroblast-like cells present in the culture were free from Theileria . During mitotic division of a host cell, parasites were found to be distributed between daughter cells . Continuous cell lines invaded with Theileria can be used as a laboratory model to study some aspects of parasite-host cell interaction. Vopr Virusol, 1975 Mar-Apr, (2), 215 - 20 {Detection of persistent infection of stable cell culture with an agent related to lymphocytic choriomeningitis virus}; Sheinbergas MM; The presence of a persisting agent related to lymphocytic choriomeningitis virus has been detected in a number of stable cell cultures of human and animal origin by means of the indirect immunofluorescence procedure. Am J Vet Res, 1975 Mar, 36(3), 247 - 50 Isolation and characterization of an adenovirus and isolation of its adenovirus-associated virus in cell culture from foals with respiratory tract disease; Dutta SK; An adenovirus was isolated from a foal with respiratory tract disease . The virus produced cytopathic effects (CPE) in equine embryo kidney (EEK) cell culture, contained deoxyribonucleic acid (DNA), was resistant to chloroform and pH 3, and was moderately resistant to heat . The virus caused hemagglutination of human (type O) erythrocytes . Viral density was 1.34 g/cm,3 and diameter was 75 nm . An adenovirus-associated virus (AAV) isolated from the infected cell culture was 22 nm in diameter . These viruses are classified as equine adenovirus and equine AAV. Vopr Virusol, 1975 Mar-Apr, (2), 183 - 6 {Dynamics of production and various properties of interferon-like inhibitors formed under the influence of AET and cystaphos in vivo and in cell cultures}; Khaitovich AG et al.; Interferon-like virus inhibitors appeared in the blood serum of animals and in the culture fluid 15 min.--1 hour and 4-6 hours after administration of AET (S, beta-amino-ethylisotiuronium) and cystaphos (monosodium salt of beta-aminoethylthiophosphorus acid) . These inhibitors showed species-specificity, were inactivated by trypsin and by heating at 37 degrees C for 2 hours and at 56 degrees C for 1 hour, did not sediment at 100,000 g . It is assumed that these are two different inhibitors of which the one forming the early peak pre-exists in the cell . It is probably associated with cell membranes and is released as a result of chemical effect of aminothyols . The late peak of inhibitor is synthesized de novo as inducated by its sensitivity to the effect of puromycin and cycloheximide. Biochim Biophys Acta, 1975 Feb 13, 381(2), 443 - 7 Synthesis of a fluorogenic mucopolysaccharide by chondrocytes in cell culture with 4-methylumbelliferyl beta-D-xyloside; Fukunaga Y et al.; Culture of chondrocytes in the presence of 4-methylumbelliferyl beta-D-xyloside resulted in a synthesis of protein-free, fluorogenic chondroitin sulfate which was heterogeneous on DEAE-cellulose chromatography . Degradation of the major chromatographic fraction with chondroitinase-ABC yielded, in addition to a large quantity of delta4-glucuronic acid-containing disaccharides, two fluorogenic oligosaccharides of different size . Quantitative analysis showed that delta4-glucuronic acid, galactose, xylose, and 4-methylumbelliferone were present in the small oligosaccharide fragment in a molar ratio of 1:2:1:1 . Since these analytical data are analogous to those reported for glycopeptides derivedfrom proteochondroitin sulfates, it may be suggested that 4-methyl-umbelliferyl beta-D-xyloside replaces the need for xylosyl protein core in the normal synthesis of proteochondroitin sulfate with a resultant production of the unusual polysaccharide bearing the added xyloside at the reducing end. J Parasitol, 1975 Feb, 61(1), 31 - 42 Ultrastructure of cytoplasmic and nuclear changes in Eimeria tenella during first-generation schizogony in cell culture; Pacheco ND et al.; Eimeria tenella sporozoites were inoculated into primary cultures of chick kidney cells . Cells fixed from 1 1/2 to 54 hr later were examined with the electron microscope . At 1 1/2 and 24 hr, most intracellular sporozoites were fusiform and retained organelles typical of extracellular sporozoites . However, at 35 hr, rounded trophozoites were present without these structures; only a refractile body, nucleus, mitochondria, and endoplasmic reticulum remained . Binucleate parasites were also present at that time, but at 48 hr many multinucleate schizonts were present . Nuclei, with adjacent conoids, were at the periphery of these schizonts . Partly developed merozoites, each containing a conoid and a nucleus, protruded into the parasitophorous vacuole . At 54 hr, fully developed merozoites were separated from the residual body . Merozoites resembled sporozoites but lacked the large refractile bodies seen in sporozoites . Linear inclusions were present near the merozoite nucleus and in the residual body . Round vacuoles and ribosomes were also found in the residuum . Nucleoli were first seen in sporozoite nuclei at 1 1/2 hr . They were also present in merozoites but were more prominent in trophozoites and schizonts . Peripheral and scattered nuclear heterochromatins were prominent in intracellular sporozoites and diminished in trophozoites, but increased after several nuclear divisions and were again prominent in the merozoite . Small, distinct interchromatin granules were found in all stages . Intranuclear spindles, centrocones, and centrioles were found in connection with nuclear divisions . Ultrastructure of first-generation schizogony in cell culture was similar to that described for second-generation E . tenella in the chicken and to schizogony of other species of Eimeria. J Gen Virol, 1975 Feb, 26(2), 205 - 8 Micromethod for the titration of lymphocytic choriomeningitis virus in cell cultures; Gschwender HH et al.; A quantal microassay for the titration of LCM virus strains is described . It is based on the detection of virus-specific complement-fixing antigen in the medium of infected L cell microcultures. J Dairy Sci, 1975 Feb, 58(2), 159 - 63 Effect of cell density on lactose synthesis in bovine mammary cell cultures; Rao DR et al.; The ability to synthesize lactose was studied in despersed cell cultures of lactating bovine mammary tissue under conditions of varying cell density, time, glucose, and lactose concentrations . The observable rate of lactose synthesis at a given time in an adequate medium is dependent on individual animal, length of time in culture, and density of cells . Rate of loss with time in the ability to synthesize lactose followed first order kinetics (half-time 11 h) . Rate of synthesis per cell at a given time was an inverse function of the cell density following a linear relationship expressed by plotting the inverse of the amount accumulated versus the inverse of the cell number . A cell density for such experimental studies of about 2.5 times 10-6 cells per ml was ideal . The medium concentration of lactose and, above a minimum, that of glucose did not affect production of lactose. J Protozool, 1975 Feb, 22(1), 107 - 10 Growth of Nosema algerae in pig kidney cell cultures; Undeen AH; Nosema algerae, a microsporidan parasite of mosquitoes, can infect pig kidney cell cultures . Sores germinated in the culture medium, infected the cells within 30 min of germination, multiplied, and produced spores . The early developmental stages in the N . algerae life cycle are discribed. Z Erkr Atmungsorgane, 1975 Feb, 142(2), 219 - 24 {Cell-culture-tests (oncobiograms) in 105 bronchial carcinomas (author's transl)}; Marzotko F et al.; Thirty-six oncobiograms (cell culture tests) of bronchial carcinomas are reported . One hundred forty-eight single tests showed a predominant cytostatic sensibility of the different squamous cell carcinomas and alluded to a special effectiveness of the alkylating chemotherapeutical agents, so that the oncobiogram may be able at the same time to support the polychemotherapy to day discussed and realized in all special branches. Pathol Biol (Paris), 1975 Feb, 23(2), 101 - 5 A cytochemical study of some enzyme activities in biliverdin-treated cell cultures; Paradisi F et al.; The authors studied the modifications of the activities of some enzymes in cell cultures submitted to the action of biliverdin . This biliary pigment rapidly induces a remarkable increase in alkaline phosphatase and ATP-ase activities and subsequently, an activation of acid phosphatase and beta-glucuronidase . On the contrary, 5'-nucleotidase and glucose-6-phosphatase activities remain unchanged . These results are discussed and compared with those obtained in our and other laboratories by using unconjugated bilirubin on different biological substrates. J Periodontol, 1975 Feb, 46(2), 86 - 9 Studies of herpes simplex virus and interferon in human gingival cell cultures; Gordon GD et al.; Cultures of human gingival fibroblast cells from patients with a positive or negative history of recurrent herpes simplex virus (HSV) infection were compared with respect to susceptibility to HSV infection and interferon activity . There was a possible inverse relationship between interferon sensitivity of gingival fibroblast cells and a clinical history of recurrent disease . No correlation was found between prior infection and other parameters of interferon activity or susceptibility of the cells to HSV. Proc Natl Acad Sci U S A, 1975 Feb, 72(2), 535 - 8 Induction of endogenous murine C-type virus in spleen cell cultures treated with mitogens and 5-bromo-2'-deoxyuridine; Moroni C et al.; In short-term cultures of BALB/c spleen cells, treatment with a combination of 5-bromo-2'-deoxyuridine (BrdU) and either lipopolysaccharide W . Escherichia coli or concanavalin A resulted in release of C-type virus into the medium . Only lipopolysaccharide induced virus release when given alone . This could be potentiated by a combined treatment with BrdU . In contrast, phytohemagglutinin at mitogenic concentration had no effect with or without BrdU, suggesting that inducibility may vary between various mitogen-responsive spleen cell populations . In AKR mice, spontaneous virus release was detectable in nonstimulated spleen cell cultures . This could be potentiated by lipopolysaccharide, whereas no further increase occurred upon additional BrdU treatment . The induced viruses had C-type characteristics in that they contained reverse transcriptase that could be distinguished from cellular enzymes by template-primer preference experiments . Furthermore, the enzyme activities were particle-associated, banding in isopycnic sucrose gradients at 1.15-1.17 g/cm-3 . The presence of C-type viruses was confirmed by electron microscopy. J Biol Chem, 1975 Jan 10, 250(1), 55 - 60 Altered ganglioside biosynthesis in mouse cell cultures following transformation with chemical carcinogens and x-irradiation; Coleman PL et al.; Chemicaly and x-ray-transformed subclones of BALB/c 3T3 mouse embryo cells were found to have reduced amounts of the mono- and disialogangliosides galactosyl-N-acetylgalactosaminyl-{N-acetylneuraminyl}-galactosylglucosylceramide (Gm1) and N-acetylneuraminylgalactosyl-N-acetylgalactosaminyl-{N-acetylneuraminyl}-galactosylglucosylceramide (Gd1a), and increased amounts of N-acetylgalactosaminyl-{N-acetylneuraminyl}-galactosylglucosylceramide (Gm2) . The activity of the enzyme UDP-Gal:Gm2 galactosyltransferase was reduced to between 2.7 and 14.3% of normal in the transformed clones . Other ganglioside glycosyltransferase activities were unaffected . This enzymatic change was consistent with the observed alteration in ganglioside pattern in the transformed cells . The residual galactosyltransferase activity in the transformed cells was kinetically similar to the normal enzyme, suggesting that transformation alters ganglioside biosynthesis by blocking enzyme synthesis at the translational or transcriptional levels. J Biol Chem, 1975 Jan 10, 250(1), 231 - 9 Effects of 6- and 8-substituted analogs of adenosine 3':5'-monophosphate on phosphoenolpyruvate carboxykinase and tyrosine aminotransferase in hepatoma cell cultures; Wagner K et al.; A variety of 6- and 8-substituted analogs of cAMP (cyclic adenosine 3:5-monophosphate) have been tested for their ability to increase activity of tyrosine aminotransferase (EC 2.6.1.5) in cultured Reuber H35 hepatoma cells . Some analogs, particularly the 8-thio-substituted ones, produced effects approximately equivalent to those generated by N-6, O2'-dibutyryl cAMP . In contrast, cAMP and its O-2-monobutyryl derivative were relatively ineffective even at very high concentrations, whereas three other analogs actually depressed the activity of the aminotransferase . Changes in enzyme activity generated by the various analogs were paralleled closely by changes in the relative rate of aminotransferase synthesis . An excellent correlation was found to exist between the ability of any given analog to influence the activity of tyrosine aminotransferase and that of phosphoenolpyruvate carboxykinase (EC 4.1.1.32) . A similar correlation was found to exist between the ability of various analogs to evelate the activity of these enzymes and to inhibit reversibly the growth of H35 cells . Only one of five inhibitors of cAMP phosphodiesterase activity tested produce any increase in aminotransferase activity when added alone . All of the 6- and 8-substituted analogs tested, including noniducers, stimulated f1 histone phosphorylation in crude rat liver extracts with approximately equal potencies . On the other hand, dibutyryl cAMP was only a weak activator of protein kinase in vitro, even though it is a potent enzyme inducer . A possible resolution of this apparent discrepancy has been provided by preliminary analyses of site-specific f1 histone phosphorylation in whole cells . Only compounds active as aminotransferase inducers are capable of stimulating phosphorylation of the serine-37 residue of endogenous f1 histone (3- to 10-fold). Tissue Cell, 1975, 7(4), 747 - 62 Purification of monolayer cell cultures of the endocrine pancreas; Braaten JT et al.; Experimental use of primary cultures of endocrine pancreas is constrained by early, vigorous proliferation of fibroblastoid cells . The addition of heavy metals, sodium ethylmercurithiosalicylate, phenyl mercuric acetate, phenyl mercuric nitrate and sodium aurothiomalate to the culture media selectively destroys these fibroblastoid cells yielding highly enriched, morphologically intact, functionally competent endocrine cells that are capable of cell replication . This action of heavy metals appears to be due to reversible inhibition of sulfhydryl enzymes since glutathione and thioglycolate were demonstrated to completely inhibit the cytotoxic effects of the mercury and gold containing agents, respectively . Certain variables in the application of the mercurial agents to pancreatic endocrine cell cultures were defined, most notably the enhanced sensitivity of fetal vs . neonatal tissue, and in inverse relationship of cell density to effective toxicity . After removal of the heavy metal agent from the culture media, many pancreatic islets send out cytoplasmic projections, containing large numbers of oriented microtubules which serve as bridging units to adjacent endocrine cells . The sustained availability of virtually pure pancreatic endocrine cell cultures, which results from the application of mercury to the culture media will undoubtedly permit many aspects of the cell biology of the endocrine pancreas to be directly and sequentially assailed. Curr Top Mol Endocrinol, 1975, 2, 293 - 309 Androgen binding in the testis: in vitro production of androgen binding protein (ABP) by Sertoli cell cultures and measurement of nuclear bound androgen by a nuclear exchange assay; Sanborn BM et al.; Androgen binding activity in the testis has two components . One component, ABP, has been shown to be produced by Sertoli cell cultures for at least 9 days in the absence of exogenously added hormones . FSH (10-100 microgram/ml) markedly enhances the secretion of ABP . MIX has a potentiating effect after long treatment intervals (7 days) . In order to study the second component, intracellular androgen receptor, a nuclear exchange assay was developed . Competition for exchange activity using 3H-dihydrotestosterone was significant for a 500 fold excess of testosterone, dihydrotestosteron, progesterone, and cyproterone acetate . The exchange activity was increased 2-10 fold by prior treatment in vitro or in vivo with testosterone . Significant exchange activity was found in long-term hypophysectomized adult and immature animals and in tubule and germ cell fractions . In isolated germ cell fractions, the highest concentration of exchange activity was associated with the most mature elements . These data suggest that androgen exchange activity may exist in both Sertoli cell and germ cell fractions and suggest that the mechanism of action of androgens in the testis is quite complex. Virologie, 1975, 26(2), 81 - 86 Variations in Coxsackie virus pathogenicity in the course of routine isolations in suckling mice and cell cultures; Ciugarin-Brailoiu M; From 1961 to 1973 416 Coxsackie viruses were isolated, most of the isolations (303) being done in the last 5 years . Most of the isolates belong to a group A, with a predominance of types A6 and A8 . Many variations were observed in strains belonging to the same type, as concerns their isolation in human embryo cell cultures and suckling mice; many Coxsackie A5, A6 and A8 strains showed a low pathogenicity for these animals. Eksp Med Morfol, 1975, 14(4), 207 - 13 {Acid phosphatase and beta-glucuronidase in the peripheral blood leukocytes and in blast transformation in cell cultures stimulated with phytohemagglutinins (PHA)}; Popova L; The author examined the enzymic content of lymphocytes and the changes, which occurred after stimulation with phytohemaglutinins (PHA) . There was a difference in the reaction of lymphocytes in healthy persons, in patients with virus diseases and in persons with malignant lympholeucosis. Vopr Onkol, 1975, 21(6), 83 - 8 {A comparative study of primary human cell cultures of diffuse goiter and cancer of the thyroid gland}; Demidova SA et al.; Cells obtained from non-malignified tissues (diffuse struma) in 83 of 100 cases formed a continuous layer consisting of monomorphous epithelioid cells possessing a high adhesive capacity . Cells obtained from thyroid adenocarcinoma (in 5 of 7 cases) showed lowered adhesiveness and did not form a monolayer . The culture consisted of polymorphous cells . Gigantic multinuclear cells and these with spheroid colorless inclusions in nuclei were encountered . In tripsinization of the tumor tissue obtained from patients, subjected to x-ray therapy, no growth of cell cultures was detected . Electron microscopic studies of nonradiated tumor tissue revealed light and dark cells, while these were light and degenerating in the irradiated tissue. Folia Histochem Cytochem (Krakow), 1975, 13(3-4), 151 - 9 Karyometric observations of WISH cell cultures irradiated with 3 GHz microwaves; Szmigielski S et al.; WISH cell cultures 24 hours after passage were irradiated with 3 GHz microwaves (10 cm) at far field conditions in free space (anechoic chamber) for 30 minutes, at field power density 5 or 20 mW/cm2 . Within 1,24 and 48 hours of the exposure to microwave fields the volumes of nuclei and nucleoli were measured with the use of a micrometer, and logvolumes and nucleo-nucleolar ratios were calculated . Under the applied irradiation conditions the culture medium temperature did not exceed 37 degrees C . In cultures irradiated at field power density 20 mW/cm2 increased number of cells with small nuclei and enlarged nucleoli was noted within 1 hour of the exposure . Within 24 and 48 hours after irradiation the nucleolar volume showed a slight decrease, whereas the nuclear volume increased . In cultures irradiated at field power density 5 mW/cm2 increased numbers of cells with enlarged nuclei and nucleoli were found . Analysis of the distribution curves of nuclear and nucleolar volumes suggests that non-thermal power densities of microwaves stimulate the metabolism of cell cultures . However, at higher power densities (20 mW/cm2) the stimulation phase is preceded by a period of reduced viability of cell cultures. Acta Biol Med Ger, 1975, 34(6), 941 - 9 {Effect of the replication of rubella virus on the protein biosynthesis of BHK 21 cell cultures}; Hermsdorf S et al.; The protein biosynthesis of BHK-21/C 13 cell cultures under the influence of multiplying rubella virus was studied by the uptake and incorporation of 14C leucine . The uptake of 14C leucine by the cells of virus-infected cultures was found to increase up to the third day after infection; no further increase was detectable on the fourth day . Control cultures maintained under the same conditions showed a similar behaviour up to the second and on the fourth day . On the third day, the virus-infected cultures exhibited significantly higher uptake than the controls . It may be that the virus infection causes damage to the cellular wall, the nature of which has yet to be elucidated . The protein incorporation of 14C leucine slightly increases in the virus-infected cultures 36 hrs after infection . This increase is not equally pronounced in the control cultures, but the differences were not significant. Vet Med Nauki, 1975, 12(7), 74 - 80 {Sensitivity of different cell cultures to 1-aminoadamantan}; Dimitrov P; Studies were carried out on the sensitivity of primary cell cultures of pig kidney (PK), pig thyroid gland (PTG), and chick embryo fibroblasts (CEF) to the synthetic viral inhibitor 1-amino adamantane (1-AA) . The 1-amino adamantane was shown to have no effect on the cell growth in the cultures of PK and PTG in a concentration of up to 50 micrograms per cu . cm, and the CEF culture in a concentration of up to 25 mcg/cu . cm . When the cultures were treated after the cellular monolayer had been formed a concentration of 50 mcg/cu . cm initiated no cytotoxic effects in PK and CEF cultures in the course of 6-days while in PTG there were no such effects for twelve days . The cytotoxic changes consisted in the appearance of rounded and swollen cells, vacuolization of the cytoplasm, and deformation of the nuclei. J Gen Virol, 1975 Jan, 26(1), 15 - 20 The multiplication of Nodamura virus in insect and mammalian cell cultures; Bailey L et al.; Nodamura virus multiplied in mosquito cell lines, as determined by infectivivity assays in adult honey bees (Apis mellifera) and wax moth larvae (Galleria mellonella) . Titres of more than 10-7 and 10-5 bee LD50 /ml were obtained in culture fluids of Aedes albopictus and Aedes aegypti cells respectively after 10 days . Comparable titres were obtained after several months, during which the cultures were subdivided up to six times . Nodamura virus also multiplied in BHK cells and yielded titres of 10-4-8 to 10-6-6 mouse LD50/ml and 10-5-1 to 10-7-1 wax moth LD50/ml in culture fluid 1 to 4 days after infection . No c.p.e . was observed in infected cells. Boll Ist Sieroter Milan, 1975, 54(1), 1 - 4 Nonvirionic inhibitor of DNA synthesis in human embryo fibroblast cell cultures infected with rubella virus; Gerna G et al.; Human embryo fibroblast cell cultures (RU-I) infected with virulent and attentuated strains of rubella virus of treated with a cell extract form infected and from control cultures have been studies in respect of their mitotic activity by evaluating the (3-H) thymidine uptake by autoradiography . The results show the presence in infected cell cultures of a nonvirionic inhibitor of DNA synthesis, which is detectable in control cell cultures too, though to a lesser degree . The relation of this inhibitor to the chalone system is so far unclear . No effect of the extracts on human chromosome pattern was observed . Attempts of biochemical characterization by fractionation of 14-C-labeled extracts on polyacrylamide gel followed by autoradiography were unsuccessful. Avian Dis, 1975 Jan-Mar, 19(1), 6 - 11 Characterization of a new infectious bronchitis virus isolate . III . Cell-culture adaptation of Clark 333; Cowen BS et al.; The Clark 333 strain of infectious bronchitis virus (IBV) was substantially resistant to primary chicken cell-culture adaptation . More than 40 serial embryo passages were required before the virus would produce cytopathic alterations upon cell-culture inoculation . The cytopathic effect was characteristic of the effect of reported for IBV . Adaptation was not accomplished by alternating serial passages in embryo and cell-cultured systems . A careful monitoring of cell-culture fluid infectivity by embryo inoculation was found to be essential because absence of adaptation is accompanied by a loss in virus titer (3 to 5 serial passages) . Helpful additional aids were immunofluorescence and cytopathology. J Virol, 1975 Jan, 17(1), 254 - 68 Replication of nuclear polyhedrosis virus in a continuous cell culture of Spodoptera frugiperda: microscopy study of the sequence of events of the virus infection; Knudson DL et al.; A microscopy study of the sequence of morphogenic events of Spodoptera frugiperda nuclear polyhedrosis virus infection of S . frugiperda cells is presented which orders the sequence of replication and establishes the time scale within which the events occur . The virus entered the cell by 1 h postinfection and was uncoated . The eclipse period was 9 h and the latent period was 12 h . Polyhedron formation was detected by 18 h postinfection and continued until the deposition of the polyhedron membrane was completed by 48 h postinfection . Aberrant morphogenic characteristics of virus repeatedly passaged in the cell culture were also recorded . Adsorption, envelope morphogenesis, and release mechanisms are discussed in light of other data on in vivo and in vitro baculovirus infections. Zentralbl Bakteriol {Orig A}, 1975, 231(1-3), 31 - 41 {Laboratory procedures in adenoviruses . II . Sensitivity of various cell cultures as determined by endpoint titration (author's transl)}; Wigand R et al.; The sensitivity of human embryonic kidney (HEK), human amnion (HAm) and HeLa cells for human adenoviruses was investigated by means of endpoint titrations of 13 prototype strains and numerous original specimens from patients . Prototypes and original specimens showed the same behavior . Adenoviruses of subgrouppp III produced nearly identical titers in all 3 cell cultures, while for subgroup I HAm cells showed a 10- to 100-fold lower titer . On the other hand, HAm cells are nearly as sensitive as HEK cells for type 8, whereas HeLa cells are less sensitive . For other viruses of subgroup II and for subgrou IV, HAm (for type 12 also HeLa) cells are less sensitive than HEK cells . Out of three HeLa cell strains tested the Bristol strain was inferior to the other two in its sensitivity . Concerning the speed of the CPE development, HEK cells are superior for all types, the difference being greatest for subgroup I towards HAm and HeLa and for type 8 towards HeLa cells . The length of incubation necessary for the appearance of CPE even with minimal amounts of virus is 40 days for type 8 in all kinds of cell cultures, whereas for adenoviruses of sub-groups I and III, which are predominantly isolated in the routine laboratory, 25 days for HEK and 30 days for HAm and HeLa cells may suffice in most cases . When endpoint titrations are compared with titers obtained by immunofluorescence, it appears that this technique may be applied as a screening method; thus long incubation periods of negative specimens can be saved . The amounts of infectious virus present in original specimens are reported; the highest quantity was found in specimens containing subgroup I viruses. Ann N Y Acad Sci, 1975, 266, 241 - 50 Arbovirus infection of vertebrate and insect cell cultures, with special emphasis on Mokola, Obodhiang, and kotonkan viruses of the rabies serogroup; Buckley SM; Multiplication of rabies serogroup viruses, Obodhiang and kotonkan (two presumptive arboviruses), was induced in vertebrate cell cultures with Singh's A . albopictus cell cultures used as "helper cells" in cocultivation experiments . Plaque formation without prior in vitro adaptation was induced in Vero cell cultures with eight rabies serogroup viruses: in all five instances by cocultivation of either infected BHK-21 or A . albopictus cells with Vero cells under agar overlay and in three of eight instances by direct plaque assay of infected mouse brain suspensions . In cross-plaque reduction neutralization tests with cloned viruses that represented human pathogens, rabies, Duvenhage, and Mokola, on the one hand, and the presumptive arboviruses Obodhiang and kotonkan, on the other hand, Mokola virus shared common antigenic components with both the nonarboviruses and the arboviruses . Biologically, Mokola virus was different from the other two human pathogens, rabies and Duvenhage, in that it multiplied in both vertebrate and invertebrate cell cultures . Mokola virus thus appears to be the biologic and serologic bridging agent. Ann N Y Acad Sci, 1975, 266, 204 - 13 In vivo behavior of a Sindbis virus mutant isolated from persistently infected Aedes aegypti cell cultures; Peleg J; A mutant of the Sindbis virus SV-S was found to interfere with the regular course of infection by the wild strain of the virus SV-W in A . aegypti mosquitoes and in suckling mice . In mosquitoes, this result was manifested by a reduced titer of SV-W in the presence of SV-S and by a failure of the mosquitoes to transmit SV-W . In the brains of suckling mice, in the presence of SV-S, the growth of sc inoculated SV-W was suppressed, and as a result, the usually lethal course of infection by this virus was converted into a nonlethal one. Adv Exp Med Biol, 1975, 53, 529 - 42 Proliferation and morphology of ascitic cells as a function of age in cell culture; Balazs A et al.; Ascitic cells in the logarithmic growth phase increase the accumulation of glycogen particles in the course of explantation into suspension culture, probably due to the increasing arrest of glycogenolytic enzymes . At this age, a part of the cells are capable of restitution by exopinocytosis of the glycogen-containing vacuoles ia formation of cytoplasmic buds . Older cells, taken from the plateau-phase, pass atypical differentiation and ageing, are less capable of hindering the abnormal accumulation of glycogen and the hypervacuolisation . As a consequence, the cells finally degenerate and die. J Dent Res, 1975 Jan-Feb, 54(1), 131 - 9 Effect of exogenous lipid on lipid synthesis by bone and bone cell cultures; Schuster GS et al.; Newborn rat calvaria and isolated calvaria cells are capable of de novo lipid synthesis when grown in the presence or absence of exogenous lipid sources . Synthesis decreases when exogenous lipids are supplied . Several cholesterol precursors were found in these tissues and the presence of dihydrocholesterol was established for the first time. Exp Pathol (Jena), 1975, 10(5-6), 318 - 32 The establishment of continuous lymphoblastoid suspension cell cultures from hematopoietic organs of baboon (Papio hamadryas) with malignant lymphoma; Agrba VZ et al.; Two continuous suspension lymphoblastoid cell cultures designated as SPG-1 and KMPG-1 have been established from the bone marrow and spleen cells of the hamadryas baboon no . 9386 with malignant lymphoma . Virus particles morphologically characterized as herpes-like have been revealed in KMPH-1 and SPG-1 cultures in 2-10% of cells . The paper describes the establishment of these suspension cultures. Zahn Mund Kieferheilkd Zentralbl, 1975, 63(2), 134 - 41 {Tissue compatiblity of stomatologic materials in cell cultures}; Neupert G et al.; The paper contains results of investigations on the suitability of cell cultures for biological testing of soluble substances from dental cements and their components . The preparation of the specimens as well as the elution process are described . Furthermore the culture system of cell populations in vitro and representative biological parameters are reported. Acta Virol, 1975 Jan, 19(1), 73 - 7 Synergic action of distamycin A and hydroxyurea on the reproduction of DNA viruses in cell cultures; Pancheva-Golvinska S; The antiviral activity of the combination of distamycin A (DA) Pand hydroxyurea (HU) on the reproduction of vaccinia and pseudorabies viruses was investigated . The drug combination exerted a significant synergic inhibitory effect on the vaccinia virus yield and on the plaque formation in chick embryo cells . Similar experiments on pseudorabies virus showed an additive effect . The possible mechanism of the mutual enhancement of the antiviral activity is discussed. Intervirology, 1975, 5(6), 342 - 53 Morphological changes in chick embryo cell cultures induced by avian leukosis viruses; Oker-Blom N et al.; Morphological alterations were observed after 5-15 serial passages of cells infected with three different strains of avian leukosis virus: OK 10, an A subgroup virus isolated from a natural infection; RAV-1, an established laboratory strain of the A subgroup, and RAV-2, a laboratory strain of the B subgroup . The infected cells had a prolonged lifespan of approximately 28 passages, compared to 14 passages for control cells . However, the altered cells had none of the attributes of transformed cells, such as growth in soft agar, loss of contact inhibition, tumor formation in chickens, or loss of fibroblast surface antigen . Therefore, we refer to the changes as conversion rather than transformation . The morphological changes differed depending upon the subgroup of the inducing virus . Cells converted with the A subgroup viruses were uniformly epitheloid whereas cells converted with the B subgroup virus were less uniform in size and shape . We speculate that an event similar to conversion may take place in vivo and contribute to the oncogenicity of leukosis viruses. Vet Med Nauki, 1975, 12(4), 10 - 5 {Localization of viral antigen in cell cultures infected with the IBR-IPV virus}; Karadzhov I; Using the immunofluorescence method and fluorescein-isothiocyanate-labelled antibodies against the IBR-IPV virus the dynamics was followed up of the production of the viral antigen in primary cell cultures of calf kidney and a permanent cell line of calf kidney infected with IBR-IPV strains isolated in this country . To avoid nonspecific reactions in the fluorescence-and-serologic demonstration of the viral antigen a method was employed for the contrast staining with Evans blue . A positive reaction consisting in the specific fluorescence of the membrane enveloping the nucleus appeared at the earliest four hours after the infection of the cell cultures . No differences were found between the studied IBR-IPV virus strains so far as the place and time of appearance and the development of the viral antigen in the infected cell were concerned with the use of the two types of cell cultures. Arch Virol, 1975, 49(4), 307 - 15 The influence of substances changing the intracellular concentration of cyclic adenosine 3'5'-monophosphate on interferon synthesis in chick embryo cell culture; Reizin FN et al.; The influence of cyclic 3'5'-adenosine monophosphate (cAMP), adrenalin and theophylline on interferon synthesis induced by influenza B virus (Lee strain) in chick embryo cell cultures was studied . In 5-day-old cell culture, theophylline was shown to enhance the inhibiting effect of exogenous cAMP and adrenalin on interferon synthesis and in 1-day-old culture, on the contrary, to enhance interferon production whereas adrenaline under these conditions had no effect on interferon synthesis at all . In 5-day-old cultures the activity of adrenalin and theophylline was manifested when they were added to the maintenance medium not later than 4 hours postinfection, and was not associated with the influence on interferon inducer adsorption on to cells or on virus multiplication in sensitive systems . Treatment of cells with these substances had no effect on interferon release from the cells . In the concentration used, adrenalin and theophylline exerted no cytotoxic effect . Theophylline inhibited incorporation of 3H-uridine and 14C-leucine into the acid insoluble fraction of the infected cells in 1-day-old cultures, while in 5-day-old cultures this was observed only when adrenalin and theophylline were used together . It is suggested that endogenous cAMP is essential for control of interferon synthesis and that different cAMP levels in cells of different ages may be one of the causes of the varying potency for interferon synthesis in young and old cell cultures. Arch Exp Veterinarmed, 1975, 29(4), 483 - 9 {Enzyme activity in cell cultures infected with herpesvirus suis}; Tatarov G et al.; The activity of succinate dehydrogenase (SDH) and lactage dehydrogenase (LDH) was studied in chick-embryo fibroblast cultures after inoculation of the virulent strain "A2" and the avirulent strain "MK" of herpesvirus suum . Strain "A2" reduced SDH activity, and so did strain MK, but here the decrease of enzyme activity was slower, and it did not become evident until the 24th hour . LDH activity fluctuated after "A2" infection but was generally increased, while there was no change in LDH activity, compared with uninfected control cells, after "MK" infection . When interaction of cell and virus took place in the presence of 5-iodo-2-desoxyuridine (IUDR), strain "A2" produced little change in the enzymes, but "MK" infection was accompanied by a definite fall in SDH and a slight increase in LDH . The presence of IUDR inhibited the proliferation of the virulent strain but had no apparent effect on proliferation of the attenuated strain "MK" . Investigation of the enzyme activity of cells infected with Aujeszky's disease virus has revealed new biological properties