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Biomedical subjects

L Viola

Publications and source records attributed to L Viola.

At least 55 records · Page 3Linked to original sources
PubMed1986

Human leukemic K562 cells: suppression of hemoglobin accumulation by a monoclonal antibody to human transferrin receptor.

The receptor for transferrin plays an important role both in tumor cell growth and in hemoglobin synthesis. In this paper, we demonstrate that the monoclonal antibody 42/6 to human transferrin receptor inhibits iron uptake in the human leukemic K562 cell line and suppresses hemoglobin accumulation in K562 cells induced to erythroid differentiation by butyric acid. In contrast, only slight inhibitory effects were observed on cell proliferation of both uninduced and erythroid-induced K562 cells treated with the 42/6 monoclonal antibody. In addition, the 42/6 monoclonal antibody to human transferrin receptor does not inhibit butyric acid-induced accumulation of gamma-globin mRNA. The effect of the 42/6 monoclonal antibody on hemoglobin synthesis appears to be restricted to human cell lines, as murine Friend erythroleukemic cells undergo erythroid differentiation when cultured in the presence of hexamethylenebisacetamide plus the 42/6 monoclonal antibody. The findings reported in this paper suggest (a) a dissociation of iron transport and accumulation of heme molecules from the expression of globin genes and (b) a different requirement of iron uptake by different iron-dependent functions such as cell proliferation and hemoglobin expression.

Antibodies, Monoclonal↗
PubMed1986

Trial of (+)-cyanidanol-3 in patients with hepatitis B chronic liver disease.

A double-blind controlled trial of 12 months' treatment with (+)-cyanidanol-3 was carried out in 26 patients with chronic hepatitis B liver disease. Treatment did not improve liver blood tests nor histological appearances of the liver, but there was a trend towards reduction of serum titres of hepatitis B surface antigen.

Catechin↗
PubMed1984

Human leukemic K562 cells: differential effects of 5-azacytidine on DNA methylation of epsilon-, gamma-globin and 7SL RNA genes.

5 Azacytidine ribonucleoside (5 Aza CR), greatly enhances erythroid differentiation of the K562(h) cell line, with a sharp increase of embryonic and fetal globin gene expression. This phenomenon is correlated with the undermethylation of gamma-globin but not of epsilon-globin, as the epsilon-globin gene is already extensively undermethylated before 5AzaCR induction. By contrast no variations in both DNA methylation and expression are observed in 7SL RNA genes.

Azacitidine↗
PubMed1984

Human leukemia K-562 cells: induction of erythroid differentiation by 5-azacytidine.

In this article we show that the cytidine analog 5-azacytidine is able to induce differentiation of the human leukemia K-562 cell line. Erythroid induction is associated with (a) an increase of the overall globin synthesis and globin mRNA accumulation, (b) a relative increase of fetal with respect to embryonic globins, and (c) a decrease of the proliferative capacity of hemoglobin-containing cells. In addition, we have analysed the DNA methylation pattern at the cleavage sites of MspI and HpaII restriction enzymes, which are known to cleave differently CCGG DNA sequences when 5-methylcytosine is present. These experiments indicate that in K-562 cells treated with 5-azacytidine, DNA becomes hypomethylated, suggesting that genetic programmes leading to an erythroid phenotype may be activated by a reduction of DNA methylation.

Azacitidine↗
PubMed1983

Platelet prostaglandin production in alcoholic liver disease.

Impaired platelet aggregation is a common finding in patients with alcoholic liver disease. This may be due to impairment of prostaglandin synthesis and alterations in the proportions of platelet membrane lipids secondary to changes in circulating lipids. Platelet prostaglandin synthesis was measured by the production of malonaldehyde (MDA), and was increased in patients with alcoholic cirrhosis compared with normal controls. Mean MDA production in cirrhotics was 3.37 nmoles MDA/10(9) platelets, and in controls 1.01 nmoles MDA/10(9) platelets (p less than 0.01). Platelet prostaglandin synthesis was significantly related to the serum cholesterol:triglyceride ratio (r = 0.73, p less than 0.005). Platelet aggregation was impaired in 12/14 cirrhotics. Five of the cirrhotics had a factor in their plasma which appeared to enhance the aggregation of normal platelets. Impaired platelet aggregation in patients with alcoholic liver disease appears to be due to a defect in intraplatelet metabolism.

Adult↗
PubMed1983

Chronic liver disease: the detection and characterization of circulating immune complexes.

Circulating immune complexes containing IgG, IgM and hepatitis B surface antigen (HBsAg) in sera from groups of patients with various liver diseases were detected by both the C1q and conglutinin solid phase assays. Elevated levels of antigen non-specific immune complexes were observed in sera from all groups and complexes containing IgG were present to a greater extent than were IgM-containing complexes. Higher levels of complexes were generally obtained using the conglutinin assay than the C1q assay and the two assays were shown to preferentially bind complexes of different size ranges and antigen-antibody ratios. Only sera from HBsAg-positive patients had complexes containing HBsAg, and although serum HBsAg titres and levels of HBsAg-containing complexes were correlated, the correlation coefficient was low. The mean levels of immune complexes and the frequency of positive sera varied between different disease categories, but there was little correlation between levels of the three types of complexes detected by the two tests. Assay of immune complexes in sequential serum samples from an individual patient revealed considerable variation in the levels of the three complex types, demonstrating that the measurement of complexes in single serum samples is of limited value in assessing the potential significance of circulating immune complexes in hepatitis B.

Antigen-Antibody Complex↗
PubMed1983

Circulating immune complexes in hepatitis B: levels, immunoglobulin class of antibody and the presence of hepatitis B surface antigen.

Circulating immune complexes containing IgG, IgM and HBsAg in sera from groups of patients with various liver diseases were detected by the Clq and conglutinin solid phase assays. Elevated levels of antigen-non-specific complexes were observed in sera from all groups and complexes containing IgG were present to a greater extent than were IgM-containing complexes. However, only sera from HBsAg-positive patients had significant levels of complexes containing HBsAg.

Antigen-Antibody Complex↗
PubMed1982

Cell-mediated immunity in HBeAg-positive homosexuals with chronic liver disease.

Chronic liver disease developing after infection with the hepatitis B virus may be due to impairment of cell-mediated immunity (CMI). In a study of CMI by the lymphocyte transformation test to two mitogens and hepatitis B surface antigen (HBsAg) the response to the mitogens, phytohemagglutinin (PHA) and purified protein derivative (PPD), was normal in all of 15 male homosexuals with HBsAg-positive chronic liver disease, indicating a normal non-specific cellular immune response. By contrast, only one of the 15 patients showed a response to HBsAg, which may explain the high prevalence of chronic HBsAg carriage in these patients.

Adult↗
PubMed1982

Detecting excessive drinking among admissions to a general hospital.

A questionnaire combining items on alcohol consumption with the four CAGE questions was used by 27 housemen to detect abnormal drinking among 520 patients of all specialties admitted to a general hospital. 15.6--23.2% of patients were classified as abnormal drinkers with the largest proportions occurring among the emergency surgical, orthopaedic, psychiatric and medical patients. 95% of the abnormal drinkers were detected by the questions on consumption alone, while 22 of the 28 patients who were identified by both the consumption and CAGE questions had been admitted as a direct result of alcohol abuse. With the aid of simple questionnaire and some encouragement, junior medical staff can become quite adept at detecting abnormal drinkers in the course of their routine practice.

Alcoholism↗
PubMed1981

Histopathology and localization of viral antigens in the liver of HBsAg positive homosexuals.

In a survey of the prevalence of chronic hepatitis B in a male homosexual population, liver biopsies were done in 28 asymptomatic patients who had persistently raised aminotransferases. Four patients had active cirrhosis (AC), 13 had chronic active hepatitis (CAH) of various degrees of severity and 11 had either chronic persistent hepatitis (CPH) or minor changes of the type seen in hepatitis B virus carriers. Core associated antigens and surface antigen, were demonstrated by the PAP immunoperoxidase method in 20 cases. Core and surface antigens tended to be present in the same areas of the biopsy and quantitation showed higher core to surface antigen ratios in CAH than in CPH, the difference being statistically significant. In seven cases no core-associated antigens were demonstrated in the presence of surface antigen: most of these patients had either inactive disease or active cirrhosis. In one carrier neither antigen was demonstrated. Ten patients had two or more biopsies. Four of these had no treatment and the amounts of core and surface positive cells in the liver did not increase. Six were treated with immunosuppressants. This did not alter the degree of either inflammation or fibrosis. but the number of surface and core antigen positive cells in the liver was higher after treatment in almost every case.

Azathioprine↗