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Biomedical subjects

V Defendi

Publications and source records attributed to V Defendi.

At least 73 records · Page 4Linked to original sources
PubMed1973

Effect of environmental pH on rescue of Simian virus 40.

Rescue of SV40 virus after Sendai virus-mediated fusion of transformed mouse or hamster cell lines with permissive monkey cells was strikingly dependent on pH in the range 6.4-8.8, with a maximum at pH 8.4. The titer of virus recovered at pH 8.4 was 2 logs higher than that at pH 7.6, and 4 logs higher than that at pH 6.4. The pH-sensitive step was neither the number of heterokaryocytes formed, which was essentially the same at pH 7.6 and 8.4, nor the degree of SV40 replication in the monkey cells, which was also unaffected by pH variation in the range 7.2-8.4.

Animals↗
PubMed1973

Analysis of minimal functions of simian virus 40. II. Enhancement of oncogenic transformation in vitro by UV irradiation.

After light UV irradiation (5,000 to 10,000 ergs/mm(2)) "complete" and "defective" simian virus 40 (SV40) showed an enhancement of oncogenic transformation capacity in Syrian hamster kidney cells in vitro up to 180 and 270% of the controls, respectively. Simultaneously with the enhancement of transformation, an increase in T-antigen induction was observed in CV-1 cells infected with light UV-irradiated SV40; infectivity, however, was correspondingly reduced by 1 log(10). After strong UV irradiation (10,000 to 80,000 ergs/mm(2)) of "complete" and "defective" SV40, transformation capacity in vitro proved to be the most resistant viral function. It was only slightly reduced in comparison with a 4 to 5 log(10) reduction of infectivity. T-antigen induction of SV40 was also equally resistant to strong UV irradiation. We found no evidence of "multiplicity reactivation" involved in the high resistance of transformation capacity of SV40 after UV irradiation. Syrian hamster kidney cells transformed in vitro by UV-irradiated SV40 contained the SV40-specific T-antigen and showed the same morphology and growth characteristics as cells transformed by non-irradiated "complete" or "defective" SV40. They induced malignant tumors after subcutaneous inoculation into Syrian hamsters.

Animals↗
PubMed1972

Cell aggregation: role of acid mucopolysaccharides.

Factors that induce cell aggregation are released by several types of chick embryo and mammalian cell cultures. These aggregation factors are also present in some serums. The factors in each of the preparations tested were inactivated by treatment with bovine testicular hyaluronidase. Conversely, hyaluronic acid promoted aggregation of only those cells that were aggregated by media containing the factors. These factors appear to be acid mucopolysaccharides, with hyaluronic acid being a major component.

Animals↗
PubMed1971

Infection and transformation of mouse peritoneal macrophages by simian virus 40.

The stimulation of DNA synthesis in mouse (C57BL) macrophages explanted in vitro was demonstrated after treatment with conditioned medium or infection with SV40. In the latter case, induction of SV40 T antigen was detected before TdR-(3)H incorporation. Even though all macrophages were infected (T antigen-positive), they exhibited considerable pleomorphism, accompanied by functional differences. Permanent lines of SV40-transformed macrophages were eventually established, and one clone was isolated which replicates indefinitely and has many properties of primary macrophages: high acid phosphatase and phagocytic activity, lysozyme production, and specific antigenic determinants. These cells differ from normal macrophages in that they contain the SV40 genome, can be trypsinized, and do not require conditioned medium for continued replication.

Acid Phosphatase↗