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At least 145 records · Page 8Linked to original sources
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↗
PubMed1997

Demonstration of cellular aging and senescence in serially passaged long-term cultures of human trabecular osteoblasts.

The proliferative capacity and cellular and biochemical characteristics of human trabecular bone osteoblasts were analysed throughout their replicative lifespan in vitro. Like several other cell types, human osteoblasts demonstrated a typical Hayflick phenomenon of cellular aging comprising a period of rapid proliferation until cumulative population doubling level (CPDL) 22 to 24, followed by a phase of slow growth and the final cessation of cell division at CPDL 32 to 34. Comparing young cells (less than 20% lifespan completed) and old cells (more than 90% lifespan completed) revealed a progressive increase in population doubling (PD) time, a decrease in attachment frequency, a decrease in the number of S-phase positive cells, a decrease in the rates of DNA, RNA and protein synthesis, an increase in the protein content per cell and an increased proportion of senescence-specific beta-galactosidase positive cells. While osteoblastic production of collagen type I decreased progressively during aging, alkaline phosphatase activity dropped rapidly after the first few passages and then remained constant during the rest of the proliferative lifespan, Significant morphological changes from thin and spindle-shaped early passage young cells to large, flattened and irregularly shaped late passage old cells full of intracellular debris were observed. In comparison, osteoblasts established from an osteoporotic bone sample showed a maximum CPDL of less than 5, had a longer PD time and exhibited abnormal senescent morphology. Thus, we have demonstrated for the first time that human osteoblasts, like several other diploid cell types, have a limited proliferative capacity in vitro and undergo aging and senescence as measured by various cellular and biochemical markers. In addition, preliminary studies show that cells from osteoporotic bone have a severely reduced proliferative capacity. This model of bone cell aging facilitates study of the molecular mechanisms of osteoblast senescence as well as factors related to osteoblast dysfunction in patients with osteoporosis.

Adolescent↗
PubMed1985

Immunocompetence of chimeric rabbits. III. Serial passage and persistence of B-lymphocyte memory.

In a model consisting of noninbred rabbits matched for major histocompatibility antigens and mismatched for immunoglobulin allotypes, using cell donors and recipients unrelated to each other, B-cell memory has been demonstrated to persist through three successive transfers for a period approaching 2 years. Memory cells from the original donor are shown to dominate specific antibody responses of the primary and secondary recipients. Vigorous antibody responses by donor-derived cells are obtained even when antigenic stimulation is delayed by several months. The data suggest that B memory cells may be particularly efficient in the colonization of recipients, and the potential significance of these findings for adoptive immunization of human bone marrow recipients is discussed.

Animals↗