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Biomedical subjects

D Viza

Publications and source records attributed to D Viza.

At least 19 recordsLinked to original sources
PubMed1992

Human immunodeficiency virus type 1 productive infection in staurosporine-blocked quiescent cells.

Staurosporine, an antibiotic known to inhibit cellular protein kinases, can reversibly block the progress of normal and tumour cells into the cell cycle. The ability of HIV-1 to infect and replicate in cells blocked by staurosporine was investigated. The results show that blocked, non-cycling cells can be productively infected by HIV-1, steadily releasing infectious progeny virus for several weeks. This suggests that at least in some cases, HIV-1 can be found in a stable and active state in resting, non-proliferating T cells.

Alkaloids↗
PubMed1992

Chemical inactivation of human immunodeficiency virus in vitro.

Most chemicals with potential virucidal activity are extremely cytotoxic even at very small concentrations, thus introducing a number of technical problems and uncertainties in the evaluation of the net virucidal effect. In the present study, an attempt was made to confirm the reported virucidal activity of certain well-known chemicals and a number of new compounds were investigated. The results suggest that HIV inactivation is dependent on the viral concentration, the time of incubation in presence of the putative disinfectant and the degree of virucidal activity of the latter. The data illustrate methodological problems arising from residual cytotoxicity of the chemical which may mask or mimic the presence of a true virucidal activity and lead to erroneous conclusions. Alcohol, the most commonly used disinfectant, was found to be ineffective for high viral concentrations, whilst sodium hypochlorite was the most efficient.

Antiviral Agents↗
PubMed1992

HHV-6 inhibition by two polar compounds.

Dimethyl sulphoxide and dimethyl formamide, two polar compounds and powerful cell differentiation inducers, inhibit HHV-6 infection when added to HHV-6-infected HSB2 cultures. This was established by a delay in the time-course of infection and in the development of virus-induced cytopathic effects. Furthermore, viral titration of supernatants showed a significant reduction (3 log10) of the number of infectious particles. Electron microscopy confirmed that viable cells and extracellular virions were present in the cultures containing the polar compounds, while in the non-treated cultures all cells were lysed and no extracellular virus was evident. The mode of action of these compounds is still unclear and warrants further investigation.

Antiviral Agents↗
PubMed1991

Dimethyl sulfoxide inhibits human immunodeficiency virus production in vitro.

LDV/7, H9, and MOLT-4, three cell lines infectible by human immunodeficiency virus were incubated with dimethyl sulfoxide, an inducer of cell differentiation. It was shown that this is a powerful inhibitor of viral production, but its effect is transient: viral production resumes when the compound is removed from the culture medium. It does not inactivate the virus, and it fails to prevent viral infection or to inhibit expression of p24 on the surface of the infected cells.

Cell Line↗
PubMed1988

Soluble extracts from a lymphoblastoid cell line modulate simian immunodeficiency syndrome (SAIDS) evolution.

Nineteen Macaca fascicularis monkeys were injected with SIV. They were subsequently divided into 5 groups. Four groups of 4 animals were injected with dialysable extracts (DLE) from a lymphoblastoid cell line which had been previously induced with DLE obtained either from the total lymphocyte population, or from the CD4 or CD8 subpopulations of mice immunized with SIV virus. The other three animals which constituted the control group received saline injections. The animals were kept under observation for a 108-day period, and the values of several biological parameters were compared in a multivariant statistical analysis. On the 108th day, the control group was significantly different from the other groups in the multivariant analysis. Furthermore, the CD4/CD8 ratio and the platelets and CD4 cell counts varied significantly between the groups in the univariant analysis. It is thus surmised that DLE obtained from CD8 cells or the total lymphocyte population of immunized animals may exert a modulating effect on the evolution of SAIDS.

Adjuvants, Immunologic↗
PubMed1988

[The regulatory role of silicon in cell division].

Several reports have suggested that silicon has an activating effect on cell proliferation. In order to test this hypothesis, both peripheral human lymphocytes and LDV/7 lymphoblast cells were cultured in the presence of a compound composed of monomethylsilanetriol (silanol), a soluble organic form of silicon, and serine. This molecule stimulates peripheral lymphocyte proliferation at an optimal concentration of 10 mg of silicon per liter of culture medium; in identical conditions, it inhibits the growth of lymphoblastoïd cells (p less than 0.001). Silanol-serine also inhibits the growth of PHA stimulated lymphocytes. The effect of silicon on cell growth has a negative correlation (p less than 0.001) with the mitotic activity of cultured cells: the more intense the latter, the stronger is the inhibitory effect of silanol-serine. This would suggest a regulatory role of this compound on the cell cycle.

Cell Division↗
PubMed1988

Intra-lymphatic administration of interleukin-2 (IL-2) in cancer patients: a pilot study.

Seven patients suffering from advanced metastatic tumours, unresponsive to standard therapies, were treated with 3 to 5 intra-lymphatic injections of interleukin-2 (IL-2) and IL-2-activated-peripheral blood lymphocytes (PBL). A partial (50-70%) regression was obtained in three of the patients, and complete regression in the other four. It thus seems that intra-lymphatic injections of IL-2 and PBL can be used for the treatment of certain solid tumours (e.g., hypernephroma, adenocarcinoma, seminoma, epidermoid carcinoma) without noticeable side effects. This method could advantageously replace intravenous IL-2 administration and warrants further investigation.

Adult↗
PubMed1987

Transfer factor in prevention of Burkitt's lymphoma relapses.

Twenty-two African children with endemic Burkitt's lymphoma entered a study to evaluate the possible efficacy of a transfer factor (TF) with specific activity against Eptein-Barr virus in preventing disease relapses. Five of eleven patients have so far relapsed in the non TF-treated group as against two of eleven in the TF-treated group. The patterns of relapse and observable increased disease free remission duration in the TF-treated group strongly suggest a beneficial effect particularly in the prevention of late relapses. A larger series of patients treated with this specific TF are needed to confirm these observations in endemic Burkitt's lymphoma.

Adolescent↗
PubMed1986

Specific transfer factor protects mice against lethal challenge with herpes simplex virus.

Bovine transfer factor (TFd) specific to herpes simplex virus (HSV)1 or to HSV2 was prepared by immunizing calves with the corresponding virus. The TFd preparations were then injected into Swiss mice in an attempt to protect them against a subsequent lethal challenge with HSV1 or HSV2 virus. It was thus shown that injection of anti-HSV TFd protects the mice against the corresponding HSV virus, whereas the injection of a nonspecific TFd (anti-CMV) fails to protect against a challenge with HSV1. Furthermore, a dose-response effect was observed, since potent TFd preparations were ineffective when they were used at one-fifth of the original concentration. It seems, therefore, that animal models may be used to assay the potency of TFd preparations specific for herpes viruses.

Animals↗
PubMed1985

Transfer factor for the treatment of HBsAg-positive chronic active hepatitis.

Transfer factor was obtained from four patients having recovered from acute type-B viral hepatitis. It was replicated in vitro using the LDV/7 lymphoblastoid cell line. This in vitro-produced transfer factor specific for hepatitis B (TFdL-H) was administered to 10 randomly selected patients with biochemically and histologically proven HBsAg-positive chronic active hepatitis (CAH) at 15-day intervals over a 6-month period. In three out of four initially HBeAg-positive patients, anti-HBe antibodies appeared when the HBeAg disappeared. In one of these patients and in two other HBsAg-positive patients, the appearance of anti-HBs antibodies was noted. The improvement in several biochemical parameters of the TFdL-H patients was statistically significant when compared with those of another group of 10 randomly selected untreated CAH patients. Liver biopsies in six out of eight treated patients showed a histological improvement at the end of the treatment. These results suggest that TFdL-H may be used with beneficial effect for the treatment of HBsAg-positive CAH.

Adult↗
PubMed1985

Transfer of reactivity with in vitro produced transfer factor in rhesus and owl monkeys.

Transfer factors against two heterologous antigens, Herpesvirus saimiri and owl monkey kidney cells, were replicated in vitro in a human lymphoblastoid cell line (LDV/7) and injected into rhesus and owl monkeys. Transfer of immunity was demonstrated by the leukocyte migration inhibition assay. This study suggests that heterologous transfer factor, replicated in vitro, can transfer cellular immunity against membrane antigens in rhesus and owl monkeys.

Animals↗