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PubMedDate not supplied

Increased response to cisplatin after long-term serial passage of a squamous cell carcinoma xenograft.

We have retrospectively investigated the response to cisplatin of a squamous cell carcinoma of the head and neck xenografted to nude mice during nine years of serial transplantation. Tumour growth rate decreased gradually. After nine years and over 100 passages, there was a sudden increase in cisplatin sensitivity. Histopathological examination showed that, of two histopathologically different subpopulations present in earlier passages, the predominant one was no longer detectable. The DNA-index did not change.

Animals↗
PubMed1981

Temperature-sensitive alteration in fusion activity of subacute sclerosing panencephalitis virus during serial passages in vitro and expression of hemagglutinin on the infected cells.

The Biken strain of subacute sclerosing panencephalitis (SSPE) virus, a maturation-defective variant of measles virus, was serially passed in human embryonic lung (HEL) cells at 37 C. The strain formed syncytial giant cells (GC) at both 37 C and 39 C, but the surface of infected cells did not show hemadsorption at early passages of the strain. However, GC-forming activity of the strain diminished at 39 C after 25 passages or more and hemadsorption on the infected cells became positive at both 37 C and 39 C after 40 passages or more of the strain. Hardly any infectious cell-free virus was detected in the culture fluid even after hemadsorption became positive. Possible mechanisms for the defect of SSPE virus were discussed.

Cell Fusion↗
PubMed1979

Duck virus hepatitis: serial passage of attenuated virus in ducklings.

The safety of three attenuated virus vaccines of proven efficacy against duck virus hepatitis was assessed by controlled laboratory studies which involved the serial transmission of the virus through groups of two-day-old ducklings known to be susceptible to the disease. Each vaccine was initially derived from a different source. Enhancement of virulence which resulted in deaths from the disease in test groups of ducklings occurred in each instance.

Animals↗
PubMed1967

Studies on the transmission of human viral hepatitis to marmoset monkeys. I. Transmission of disease, serial passages, and description of liver lesions.

Inoculation of human serums or plasmas obtained during the early acute phase of viral hepatitis induced chemical and morphological hepatic disease in marmosets in two out of five experimental series. The disease was transmissible in series from marmoset to marmoset with an apparent increased virulence of the causative agent in later marmoset passages. The chemical evidence for the disease was elevation of the activity of SGOT and SICD and of serum bilirubin. In serial liver biopsy specimens interpreted under code, a hepatitis, exhibiting some of the characteristics of human viral hepatitis, was readily distinguishable from nonspecific changes. The morphological changes preceded the biochemical alterations and persisted after them. The data reported in these studies indicate that marmosets may be susceptible to human hepatitis. If these observations are confirmed, these animals may provide good experimental models for this disease. Final proof that the hepatitis observed in marmosets is caused by agents of human viral hepatitis is still lacking.

Animals↗
PubMed1991

Growth characteristics and metastatic potential of seven intestinal carcinoma lines serially passaged in syngeneic rats.

Transplantable tumour lines were obtained from one duodenal carcinoma induced by N-methyl-N'-nitro-N-nitrosoguanidine in the Lewis rat and from six colonic carcinomas induced by 1,2 dimethylhydrazine in BDIX or Fisher rats. The tumours were serially transplanted by the subcutaneous route into homologous syngeneic rats. The seven tumours differ from one another in their histological structure, five of them being well or moderately differentiated adenocarcinomas, and in their capacity to produce neutral or acidic mucins. The seven tumours also differ in their growth rate. The seven lines produced metastases; the metastatic potential and the location of the metastases differed from one line to another. The seven lines kept their original differentiation characteristics through multiple passages, representing several years of transplantation into syngeneic hosts. These tumours represent a useful and diversified model of metastatic intestinal carcinoma, available for basic research and therapeutic trials.

Animals↗
PubMed1978

Loss on serial passage of rhesus monkey kidney cells of proteolytic activity required for Sendai virus activation.

Primary and secondary cultures of rhesus monkey kidney cells supported multiple-cycle replication of Sendai virus, but later passages lost this ability, and this was reflected in decreased plaque formation. Multiple-cycle replication also did not occur in LLC-MK2 cells, a continuous line of RMK cells. Failure of replication in serially passed cells was correlated with a decrease in proteolytic cleavage of a viral surface glycoprotein (Fo), and the ability of cells to support multiple-cycle replication and plaque formation could be restored by the addition of trypsin (0.3 microgram/ml) to the overlay medium. The use of wild-type virus, which requires trypsin, and protease activation mutants that require chymotrypsin or elastase for activation has provided evidence that the activating protease supplied by primary or secondary cells has trypsin-like activity. Inactive virus, with uncleaved Fo glycoprotein, absorbed to primary or secondary cells but did not infect them, even though such cells possess the enzyme that is capable of cleaving the Fo glycoprotein of virus synthesized in these cells. The inability of these cells to activate adsorbed virus indicates that the activating protease that they possess is inacessible to adsorbed virus, although it can act on the Fo glycoprotein during virus maturation in these cells. These data provide a biochemical explanation for the failure of later passages of a cell strain or a continuous cell line to support the replication of a paramyxovirus.

Animals↗
PubMed1985

Primary culture and serial passage of normal and carcinogen-treated rat mammary epithelial cells in vitro.

A newly developed culture system was used to examine the proliferative potential of rat mammary epithelial (RME) cells in vitro. RME cells were obtained by enzymatic dissociation of mammary tissues of 45- to 50-year-old virgin female LEW rats. The tissues were dissociated to small aggregates (10-50 cells per aggregate) separated from stromal cells and plated at a density of 10(5) cells per 60-mm tissue culture dish. The cells were grown in Ham's medium F12 supplemented with 5% fetal bovine serum, insulin, hydrocortisone, epidermal growth factor, prolactin, progesterone, and cholera toxin. Plating of 10(5) cells as small aggregates resulted in the attachment of 1,000-1,500 aggregates per plate. When grown on tissue culture plastic, approximately 1-2% of these aggregates gave rise to rapidly proliferating epithelial colonies. Individual colonies expanded with a population-doubling time of 24-34 hours and grew for about 3 weeks. Although these cells grew well in primary culture, they were not subculturable. When RME cells were plated onto dishes coated with type I collagen, the number of rapidly proliferating epithelial colonies per dish increased fivefold to tenfold. Cells grown on type I collagen-coated dishes expanded with a population-doubling time of approximately 27 hours and after 2 weeks in primary culture were nearly confluent. Unlike cells grown on plastic, RME cells grown on type I collagen were readily subculturable and serial subculture resulted in the cells undergoing 15-20 population doublings (5-6 passages) before exhibiting any loss of growth potential. Continued feeding of senescent cultures resulted in the emergence of discrete RME cell foci that retained proliferative potential and that eventually developed into rapidly growing cell strains. Exposure of primary cultures to the carcinogen N-methyl-N'-nitro-N'-nitrosoguanidine (CAS: 70-25-7) enhanced the proliferative potential of RME cells in early passages and in later passages either delayed or eliminated the "senescent" phase of cell growth. Carcinogen treatment of RME cells also facilitated the establishment of rapidly growing cell strains with long-term growth potential (greater than 20 passages).

Animals↗
PubMed1979

Neuroendocrine cells in serially passaged rat stomach cancers induced by MNNG.

Five gastric carcinomas, induced in inbred Wistar rats by oral administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) dissolved in drinking water, were successfully transplanted to isologous rats. The transplants grew to a size of 10 to 35 mm in diameter within 8 to 25 weeks of implantation. In one case, serial transplantation were maintained up to the 11th generation, with occurrence of distant metastasis in the 3rd generation. Histological histochemical, and electron microscopical comparison of the original and transplanted tumors revealed that (1) the original tumors were quite well differentiated, forming either papillary or tubular structures, whereas the transplants were more anaplastic and pleomorphic showing often solid nests; and (2) tumor cells with gastrointestinal differentiation and cells with neuroendocrine differentiation were present and evenly distributed in both the original and the serially transplanted tumors. As it is unlikely that the normal and neoplastic neuroendocrine cells are growing side-by-side with and independently of the epithelial neoplastic components in the present series of transplants, the findings strongly suggest (1) the multidirectional potency of the inbred rat stomach carcinoma cells and (2) the common neoplastic origin of the epithelial and neuroendocrine components.

Animals↗
PubMed1984

Primary isolation and serial passage of hepatitis A virus strains in primate cell cultures.

Although several primate cell types have been reported to support replication of hepatitis A virus, optimal conditions for the isolation and production of quantities of virus have not been defined. We therefore examined seven different primate cell types for their ability to support replication of primate-passaged and wild-type virus as reflected by intracytoplasmic accumulation of viral antigen (direct immunofluorescence and radioimmunoassay) and propagation of cell culture-adapted virus. Of the cells tested, low-passage African green monkey kidney (AGMK) cells were most sensitive for initial isolation. Viral replication was documented after inoculation of AGMK cells with seven of nine hepatitis A virus antigen-positive fecal specimens (from seven epidemiologically distinct sources). With six inocula, virus was successfully passed in serial cultures. AGMK-adapted virus was readily propagated in continuous AGMK (BS-C-1) cells. The optimal temperature for the growth of virus in BS-C-1 cells was 35 degrees C. Viral release into supernatant fluids was documented in the absence of any cytopathic effect, and infectivity titers in supernatant fluids 21 days after inoculation (50% tissue culture infective does [TCID50], 10(6.0)/ml) equalled or exceeded those in the cell fraction (TCID50, 10(5.5)/ml). Cells maintained in serum-free media readily supported viral growth, with yields of virus (TCID50, 10(6.5)/ml) equal to or greater than those obtained with cells maintained in 2% fetal bovine serum.

Animals↗
PubMed1984

Growth and serial passage of Pneumocystis carinii in the A549 cell line.

Pneumocystis carinii obtained from infected rats and patients was cultured in the A549 cell line, a presumptive alveolar type 2 cell line derived from a human lung carcinoma. Standard criteria were established for organism sampling, quantitation, and growth. The trophozoite form of P. carinii was a more sensitive indicator of growth than was the cyst. Rat P. carinii increased 10-fold in primary culture and could be serially passed three additional times to new cultures; success in growing human P. carinii was limited and appeared to be related to the quality of the specimen received for culture. Growth pattern experiments suggested that close interaction of P. carinii with the cell monolayer is an important step in the life cycle of the organism. Thus, the A549 culture system should be useful for in vitro studies of the immunobiology of P. carinii.

Animals↗
PubMed1980

Effect of serial passage in female nude athymic mice on androgen dependency of Shionogi carcinoma 115.

When Shionogi carcinoma 115 (SC115, an undifferentiated medullary carcinoma showing a compact cell pattern and containing androgen receptor) was transplanted into male and female DS mice, it grew only in males. In contrast with this strict androgen dependency in DS hosts, SC115 tumors grew in male and female nude athymic (BALB/c-nu/nu) mice. Although most of the tumors developing in female nude mice were composed of spindle-shaped cells and did not contain androgen receptor, about 5% of tumors in female nude mice retained morphological and biochemical characteristics of the original SC115 tumor. Such a tumor was serially transplanted in female nude mice. Although no significant changes were detectable in histological and chromosomal features and in androgen receptor values, the growth speed in female nude mice accelerated and became comparable to the growth speed of the original SC115 tumor in intact male DS mice. However, this subline of SC115 tumor showed a marked androgen dependency when reinoculated into male and female DS mice after 14 passages in female mice nude mice in spite of its relative androgen independency in nude hosts. Therefore, the present results seem to suggest that the immunological status of the hosts may affect the hormone dependency of tumors.

Androgens↗
PubMedDate not supplied

Stability of ras oncogene mutation in the human tumor xenografts through serial passages.

We examined the Ki-ras oncogene point mutation in primary tumors and tumor xenografts as a marker of genetic stability. We detected point mutations at codon 12 of the Ki-ras oncogene in 21.3% (17/80) of the tumor xenografts as well as 21.0% (17/81) of the primary human neoplasms. The mutation from GGT (glycine) to GAT (aspartic acid) was the most frequent mutation in the tumor xenografts (64.7%, 11/17) as well as in the primary human neoplasms (64.7%, 11/17). The point mutation at codon 12 of the Ki-ras gene showed no discrepancy between the original human neoplasms and their xenografts in all 19 cases. The findings suggested that the point mutation at codon 12 of the Ki-ras gene was very stable in human neoplasms and their tumor xenografts through serial transplantation.

Adenocarcinoma↗
PubMed1990

Serial passage of west-European sporadic non-A non-B hepatitis in rhesus monkeys by inoculation with fecal extracts.

An experimental model of sporadic non-A non-B hepatitis involving a Fab nonimmune binding activity in stools was established in the rhesus monkey. The first animal was inoculated intravenously with a stool extract from a French patient who had never left the country and in whom post-transfusion hepatitis was excluded. Four passages were performed, and the infection was transmitted by parenteral as well as the oral routes by inoculation of stools or liver extracts. Infection led in three monkeys to reversible hepatocyte injury manifested by a transitory increase in serum aminotransferases. The other three animals, in which persistently high levels of aminotransferases was observed, were sacrificed on day 60 after inoculation. The incubation period, as evidenced by elevation of aminotransferases was about 3 to 4 weeks. The infectious agent was transitorily present in the stools before aminotransferase elevation. The presence of the infectious agent in the stools was correlated with the nonimmune Fab binding activity.

Adult↗
PubMed1991

Serial passage of embryonic human astrocytes in serum-free, hormone-supplemented medium.

We applied serum-free cell culture methods that allow extended proliferation of mouse astrocyte precursor cells to the multipassage culture of embryonic human brain cells. Cells were cultured in nutrient medium supplemented with insulin, transferrin, epidermal growth factor, fibroblast growth factor, heparin, high-density lipoprotein, and fibronectin. Cultures were maintained for a maximum of 70 population doublings before proliferation ceased. The cells synthesized glial fibrillary acidic protein, an astrocyte marker, and expression of this protein was increased by incubation of the cells with transforming growth factor beta or serum. These results identify extracellular factors important for proliferation and differentiation of embryonic human astrocytes and provide a controlled system for multipassage culture.

Astrocytes↗
PubMed1987

DNA cross-linking following exposure to cis-platinum in primary and serially passaged cultured cells derived from two murine fibrosarcomas.

We compared the kinetics of the repair of total (ISC plus DPC) cross-links and of proteinase-resistant (ISC) cross-links in cultured cells derived from two murine fibrosarcoma tumors, FSA and NFSA, after treatment with cis-platinum (cis-DDP), using a modification of the alkaline elution technique. The two tumors had previously been characterized for their response to cis-DDP in vivo; FSA cells gradually removed cross-links from their genome, whereas the NFSA cells showed no capacity to repair these lesions. The aim of the present study was to establish whether treatment of cells from these same two tumors grown under controlled culture conditions would affect either the nature of the lesions induced by cis-DDP or the kinetics of repair of these lesions when compared with tumors treated with cis-DDP in vivo. The culture conditions represent two situations: in the first, the cells in culture approximated the proportion of tumor and normal host cells present in vivo, and in the second, the normal host cells had been eliminated by subculturing to produce cultures composed entirely of tumor cells. All cells were exposed to cis-DDP (either 10 or 20 micrograms/ml) for 1 h. The relative amounts of total cis-DDP-induced DNA crosslinks and of ISCs were then determined at various times after treatment. The results show that there was little difference in the behavior of these cultured cells compared to the in vivo response of the tumor from which they were derived. For FSA, each cell culture exhibited a capacity to repair DNA cross-links comparable to that of the tumor in vivo. For NFSA, the passaged cells again paralleled the behavior of that tumor in vivo, although in this case by showing no measurable capacity to repair cross-links. The absence of a significant repair response in the NFSA tumor therefore appears to be an intrinsic characteristic of these tumor cells.

Animals↗
PubMed1978

Serial passages of larval Echinococcus granulosus from equine origin in mice. II. Infections with sterile cysts.

Sterile secondary E. granulosus cysts less than or equal to 1 mm in diameter, collected from mice 6-13 months after experimental infection were transferred to helminth-free mice. They developed into larger cysts showing fertility and daughter cyst formation at autopsy 9--14 months p.i. Average growth of the largest cyst per mouse, expressed in log volume (microliter), amounted to 0.30 +/- 0.03 per month; average growth of all cysts per mouse, expressed in log weight (mg) amounted to 0.27 +/- 0.02 per month. An inversed ratio was found between total parasite weight and number of cysts injected. The practical importance of these observations is discussed.

Animals↗
PubMed1978

Serial passages of larval Echinococcus granulosus from equine origin in mice. III. Infections with sterile daughter cysts.

Daughter cysts 0.2-3.0 mm in diameter from secondary Echinococcus granulosus cysts, collected from mice one year after experimental infection, were transferred to fresh mice. The metacestodes developed into larger cysts showing fertility and daughter cyst formation at autopsy 9-14 months post infection. The average total growth of all cysts per mouse expressed in log weight (mg) amounted to 0.25 +/- 0.03 per month. Thus, for the maintenance of the parasite in mice, daughter cysts can be used as successfully as protoscolices and small 'latent' cysts.

Animals↗