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Biomedical subjects

A L Chapman

Publications and source records attributed to A L Chapman.

At least 37 records · Page 2Linked to original sources

Growth of a heterologous tumor cell line in neonatal rats with graft-versus-host disease.

The ability of a hamster tumor cell line (T20) to grow and exhibit type H virus particles was significantly enhanced in neonatal DA rats with graft-versus-host disease (GVHD). Tumor growth peaked on days 4 and 7 in control littermates receiving adult syngeneic cells or no cells at birth, respectively, and then subsequently disappeared. However, tumor nodules in animals with GVHD became significantly larger than those in controls by day 7 and continued to grow until death. In addition, a marked plasma cell infiltration was noticed in such rapidly growing tumors from animals with GVHD only. In the light of previous studies, evidence is discussed for an environment within animals with GVHD conducive for tumor cell growth because of a depletion of T-cell areas within their tissues.

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Human and primate poxviruses: I. Growth characteristics of cytolytic and tumor variants.

The dual potential of poxviruses to be cytolytic and tumorgenic has been extended. Yaba monkey tumor virus formed foci on monkey and human embryonic cells. Cytolytic or plaque-forming virus was isolated from Yaba tumor homogenates by selective sucrose centrifugation and passage through monkey or human embryonic cells. Monkey pox virus (MPV) was cytolytic for monkey cells or human embryonic cells, but upon passage onto young monolayers of human carcinoma cells, HeLa, produced a restricted cytopathic effect on first transfer, foci on second transfer and cytolysis after the fourth transfer. If HeLa monolayers were compact, the rapid growth precluded overt expression of cytolytic MPV. Electron micrographs of cytolytic Yaba indicated that Yaba development was similar to vaccinia and MPV but not totally organized. Growth curves of vaccinia, MPV and cytolytic Yaba were essentially identical in monkey and human embryonic cell lines.

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Aberrant viruses in cells infected with murine sarcoma virus-feline leukemia virus.

This study describes an unusual type of virus seen when a feline leukemia virus (FeLV) pseudotype of murine sarcoma virus (MuSV) obtained by cocentrifugation procedures infected feline embryo cells (FEF) and two Crandell cat cell lines (CrFK1, CrFK2). When all three cell cultures were infected with MuSV-FeLV, only FEF and CrFK2 were transformed and only these showed normal and aberrant virus. The CrFK1 infected with MuSV-FeLV did not transform but did replicate normal type-C virus with a 50-A intermediate coat. The virus replicated in the two transformed lines showed three particles; a normal particle with a 50-A intermediate coat, a normal particle with a 100-A intermediate coat, and an aberrant particle with a 100-A intermediate coat.

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Establishment of two canine sarcoma cell lines: productive infection with feline leukemia virus.

Two canine sarcoma cell lines (11028, 11031) were established in vitro and have been transferred 213 and 306 times, respectively, since 1970. These cell lines had a chromosome pattern consistent with their canine origin. Both cultures were infected with feline leukemia virus (FeLV), which caused a morphologic and karyotypic changes. The cells became rounded after infection with FeLV and both cultures showed the presence of a single, large, acrocentric chromosome considered to be a marker chromosome. All tumors were transplanted into newborn beagle pups, but only the 11028-FeLV formed metastatic tumors. No helper or focus-forming activity or virus particles were found in the uninfected cultures. Helper activity and virus were demonstrated in both sarcoma lines after infection with FeLV, though no focus-forming activity was noted. Helper activity of progeny virus could be assayed on either cat or dog embryo cells.

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