Biomedical subjects
Publications and source records attributed to J Peries.
This preliminary study shows, for the first time to our knowledge, decreased whole blood serotonin levels in AIDS patients as compared to healthy controls and cancer patients. The lowest serotonin levels were found in AIDS patients with neuropsychiatric symptoms. Finally the present data suggest an inverse relationship between serotonin level and AIDS severity.
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Dexamethasone treatment enhances expression of transposable intracisternal type A particles (IAP) at RNA and proteins levels in a murine retrovirus-transformed cell line (Ki-BALB). This effect was ascertained by electron microscopic numeration of IAP. By sequence comparison, we located glucocorticoid-responsive elements in IAP long terminal repeats. Their regulatory potential was tested on the promoter activity of an IAP long terminal repeat construct coupled with the chloramphenicol acetyltransferase gene. Our findings suggest that the IAP activation by dexamethasone occurs at the level of transcription.
Significantly (p less than 0.001) decreased whole blood unconjugated serotonin levels were detected in AIDS patients as compared to patients with advanced cancers and to healthy individuals.
Embryonal carcinoma (EC) cells are malignant components of murine teratoma tumors. To extend our earlier findings concerning c-Ki-ras amplification in the embryonal carcinoma PCC4 cell line, we examined the c-Ki-ras protooncogene and its expression in other EC cell lines. We report here that c-Ki-ras amplification is not a general feature of EC cell lines since neither PCC3, PCC6, nor F9 cell lines have an amplified copy number of this protooncogene. Furthermore, molecular analysis of three independently passaged PCC4 cell lines showed marked heterogeneity for c-Ki-ras amplification. Two PCC4 cell lines showed amplified copy number and elevated expression of c-Ki-ras whereas the original one does not, suggesting that this gene amplification occurred through laboratory passage. Malignancy in syngeneic mice of PCC4 with or without an amplified c-Ki-ras gene was also examined. Our results indicate that c-Ki-ras amplification alone is not a determining factor in the malignant behavior of EC cells.
We demonstrate that Simian Foamy viruses (SFV) types 1, 2, 4 and 10 do not induce Interferon (IFN) production in mouse and primate (simian and human) cell lines, but that their cytopathogenic effect is blocked by this viral inhibitor. The mechanisms of action of IFN seems to be different from that of other Retroviridae. No trapping of virions appears in treated cells examined by ectron microscopy. Moreover, neither precursor nor mature virus particles were observed in infected cultures submitted to IFN treatment.
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Three cell lines tera I, tera II, and PA1, derived from human teratocarcinomas were tested for their capacity to produce interferon (IFN) and for their sensitivity to both human IFN-alpha and IFN-beta. When treated with Newcastle disease virus or Sendai virus, or a synthetic polyribonucleotide, poly(rI):poly(rC), tera I cells produced no IFN and the 2',5'-oligoadenylate (2-5A) synthetase enzymatic pathway was not activated, although there was an increase in protein kinase. In contrast, tera II and PA1 cells produced IFN and both enzymatic activities were detected. IFN treatment has no effect on the growth of any of the cell lines. Tera I and PA1 cells did not develop resistance to challenge with vesicular stomatitis virus or encephalomyocarditis virus, but the growth of a type-C baboon retrovirus was inhibited. Tera II cells were protected against all three viruses. It appears that human teratocarcinoma cell lines can thus differ greatly in their ability to produce IFN and to respond to it.
Simian Spumavirinae serotype, SFV10, of a Papio cynocephalus baboon, was used to infect a human lymphoblastoid cell line, LV2. Permanent growth and morphological alterations of infected cells occurred, even though no viral particles were detected. Evidence for the presence of viral genomes in the modified cell line is provided indirectly from immunological studies and induction experiments followed by coculture procedures. The permanently modified cell line obtained (LV2-FB10) is an interesting model for the investigation of the possible integration of foamy viruses into the host genomes.
The present study concerns the purification and partial characterization of simian foamy virus type 1 (SFV 1) structural core polypeptides. The obtention of SFV 1 cores separated from envelope components after viral disrupture was verified by electron microscopy (EM), density gradient, and polyacrylamide gel electrophoresis (PAGE). Multistep purification by column chromatography, verified by PAGE, enabled us to separate the structural core polypeptides from the 80,000 molecular weight reverse transcriptase. Two species of structural core polypeptides were identified with apparent molecular weights of 51 and 15 kd. By affinity chromatography on a double-stranded DNA-cellulose column, the main internal protein, p51, was shown to be composed of a major 30 kd protein and a minor 19 kd polypeptide, which binds to double stranded DNA. The p15 internal protein was shown to have a ribonucleotide binding nature.
We examined the expression of four cellular proto-oncogenes in two teratocarcinoma cell lines, one undifferentiated and malignant (PCC4), one differentiated and non malignant (PCD1). In this paper we report that transcript levels of c-Ki-ras, c-myc and c-fos are significantly higher in PCC4 cells whereas transcripts of c-Ha-ras are unchanged. Southern blot analysis does not reveal any structural alteration of c-myc and c-fos in PCC4 cells. On the contrary, the c-Ki-ras proto-oncogene is amplified 10 to 20 fold in PCC4 cells.
Long-term treatment of a murine retroviral-transformed cell line (Ki-Balb) with 50 units/ml of interferon (IFN) resulted in a morphological reversion. The effects of IFN on myc and Ki-ras oncogene expression were examined after 6 months of treatment. mRNA dot and Northern blots hybridization analysis reveal that the expression of c-myc at the RNA level decreases by about fourfold. This reduction in the c-myc mRNA appears to be selective since in the same cells v-Ki-ras and an endogenous retroviral gene, intracisternal A particles (IAP), are increased four- and threefold, respectively. No significant inhibition of cellular growth and cell-cycle distribution was observed in IFN-Ki-Balb-treated cells.
Two stable monoclonal hybridoma cell lines secreting type-specific antibodies against the human papillomavirus type 1 (HPV-1) were isolated. The monoclonal antibodies detected HPV-1 antigens in frozen sections of HPV-1-induced warts, using immunofluorescence or immunoperoxidase techniques, and they reacted with HPV-1 particles in an immunodiffusion test. The two monoclonal antibodies recognized the major structural viral polypeptide, with a molecular weight of 54 000, and a minor polypeptide, with molecular weight of 76 000, in both the dissociated viral particles and in the wart extracts.
5-Azacytidine activates the production of intracisternal A particles (IAPs) in mouse Ki-BALB cell line as ascertained by electron microscopy scanning and numeration. Efficiency of the activation is higher than that obtained with iododeoxyuridine. The increase in particle production is concentration and time dependent. The results obtained in our system correlate the high IAP expression after drug treatment with a demethylation of IAP-related genes sequences.
In a study concerning five CMV-infected bone-marrow-transplant recipients, five congenital CMV diseases and appropriate controls, presence of high levels of circulating interferon (IFN) was demonstrated exclusively during the course of CMV disease. This interferon was predominantly "immune" or gamma interferon (gamma-IFN). These results suggest that during CMV disease the interferon compartment of the immune response is modified.
A study was made on the effect of human interferon (HuIFN) on the synthesis and release of type D viruses (MPMV and SMRV) by chronically infected human lines. Interferon at concentrations of 50 IU/ml lead to an inhibition of the extracellular virus production by about 50%-80% as measured by virus-associated reverse transcriptase activity, by metabolic labeling of the virus with (3H) uridine or (3H) amino acids, or by electron microscopy counting of particles. The profiles of intracellular viral proteins, as visualized by radioimmunoprecipitation and electrophoresis, were not different in control or IFN-treated cells and the yield of intracellular protein p27 stayed unchanged or was slightly increased. Electron microscopy of thin sections taken from the control and IFN-treated cells revealed no difference in any subcellular structures including that of the viruses. However, electron microscopic examination of IFN-treated cells showed an increased number of either budding particles and intracytoplasmic precursors (two- to five-fold) or mature virus particles (four- to ten-fold) on the cell surface of the IFN-treated cells. These results indicate that IFN inhibits further developments of MPMV and SMRV replication as was described for type C and B retroviruses.
Five monoclonal hybridoma cell lines secreting antibodies against bovine rotavirus have been produced and four of them characterized by immunostaining of structural polypeptides electrophoretically transferred on to nitrocellulose sheets. Three hybridomas appeared to be directed against the major structural polypeptide (VP39) of the virion. These three monoclonals cross-reacted with the major polypeptide of simian rotavirus and human rotavirus. A fourth hybridoma appeared to react specifically with the high-molecular weight external polypeptide (VP89) and its cleavage products. A cross-reaction was observed with human Wa strain but not with SA11. The fifth hybridoma, even though reacting in an immunofluorescent test, did not show any reactivity by immunostaining. None of the monoclonals neutralized the infectivity of bovine rotavirus.
Two main intracisternal-A-particle-specific RNA species (29 to 30S and 35 to 36S) are variably expressed in particle-producing and particle-nonproducing murine teratocarcinoma cell lines. An analysis of DNA methylation patterns after hybridization with an intracisternal-A-particle-specific probe showed an apparent direct correlation between DNA methylation and RNA expression. However, when the methylation assay was performed on the excised intracisternal A particle genes in one of the particle-rich cell lines (PCC6), some undermethylated sequences were detectable. These results are consistent with the concept that only few of the genes are transcriptionally active.