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Biomedical subjects

A Angeloni

Publications and source records attributed to A Angeloni.

8 recordsLinked to original sources
PubMed1992

Infection by human herpesvirus 6 (HHV-6) of human lymphoid T cells occurs through an endocytic pathway.

We have analyzed by immunoelectron microscopy the early events of binding and internalization of human herpesvirus 6 (HHV-6, strain GS) on a susceptible T-lymphoblastoid cell line, HSB-2. The virions bound to the cell surface at 4 degrees C were tightly associated with the plasma membrane. Gold immunolabeling of the viral envelope proteins was strong and specific. Warming at 37 degrees C for different times showed viral internalization through smooth surfaced pits and vesicles. Fusion events of the virions with the cell plasma membrane were never observed. Gold immunolabeling performed in parallel experiments before or after viral internalization showed: (1) absence of viral envelope proteins on the cell plasma membranes at all times of internalization, again excluding fusion events; (2) entry of the virions with their envelopes. Treatment of the cells with chloroquine, a drug known to affect the endocytic pathway, led to an almost complete inhibition of viral infectivity, suggesting that the endocytosed virions are responsible for a successful infection. Comparable results were obtained using a second strain of HHV-6 (BA92), with biologic and molecular characteristics similar to the prototype strain Z29. The chloroquine inhibition was effective on two different T cell lines (HSB-2 and J-Jhan), as well as on phytohemagglutinin-stimulated peripheral blood mononuclear cells.

Cell Line↗
PubMed1991

[24-hour blood pressure: effects of sports in aged subjects].

The present study deals with the blood pressure (BP) and heart rate (HR) 24-h pattern in aged people of both sexes ranging in age from 66 to 75 years. 20 subjects were active in agonistic sports (running and swimming), 20 others had sedentary habits. BP and HR were studied by non-invasive monitoring along with chronobiometric analysis. The BP and HR 24-h pattern was seen to preserve its circadian rhythm in both aged athletes and sedentary elderly. The analysis reveals that the aged athletes show a higher mesor for systolic BP and a lower mesor for diastolic BP and HR. The daily pressure load, as the integral of the BP 24-h values multiplied by the HR mesor, is lower in aged people practising sport as compared to age-matched individuals with sedentary habits. The spectral analysis reveals that physical exercise acts to change the time structure of BP and HR 24-h patterns. The conclusion is drawn that active sport plays beneficial effects in aged people because of a lower pressure load.

Aged↗
PubMed1990

Epstein-Barr virus internalization and infectivity are blocked by selective protein kinase C inhibitors.

Selective protein kinase C inhibitors can either block or significantly reduce Epstein-Barr virus infectivity: inhibition of transformation and decreased 3H-thymidine (3H-TdR) incorporation in human B lymphocytes infected with B95-8 EBV, as well as a significant reduction in the induction of early antigens in Raji cells superinfected by P3HRI EBV was achieved by pre-treating the cells with the inhibitors. The inhibitors do not act by blocking binding of the virus to its cellular receptor CR 2, but rather are effective in the viral internalization process. Our results suggest that protein kinase C may be involved in the process of viral entry into cells.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

The role of calcium precipitation in the sulfoglycolithocholate-induced cholestasis of the bile fistula hamster.

Sulfate glycolithocholic acid (SGLC) has been shown to be highly cholestatic in the rat. This study was performed in order to gain understanding of the mechanisms of SGLC-induced cholestasis and the aim of the investigation was to explore the hypothesis that SGLC could cause a precipitation of calcium in bile. We studied the effects of intravenously administrated SGLC on bile flow, biliary lipids secretion and calcium excretion in the female bile fistula hamster. We also performed in-vitro studies with a Ca2(+)-selective electrode in order to measure the calcium binding capacity of SGLC. The results showed that after 1 h of infusion of 8 mumol/100 g body weight [14C]SGLC bile flow dropped to zero. During the infusion period a fine white sludge was visible in the test tube used for bile collection. TLC and HPLC analysis of both the supernatant and the precipitate showed that unchanged SGLC was excreted into bile. Up to 20% of biliary SGLC and more than 50% of the total Ca2+ present in bile was precipitated. The SGLC/Ca2+ molar ratio in the precipitate was 1.12 +/- 0.3 (mean +/- S.D. of four experiments). Light and electron microscopy of the liver did not show any specific abnormalities. The Ca2+ binding activity of SGLC in vitro, was highest among the bile acids tested at a concentration of 0.1 mM, when almost 100% of bile acids are in the monomeric (non-micellar) form. This suggests that among the bile acids, SGLC exerts the strongest binding activity on free calcium ions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Lymphocyte function tests in cirrhotic patients under treatment with spironolactone and potassium canrenoate.

This controlled study in cirrhotic patients investigated whether two antialdosteronic steroids, spironolactone (100-200 mg/day; n = 12 patient pairs) and potassium canrenoate (50-100 mg/day, n = 32 patient pairs) which are reported to bind to intracellular membranes and modify cytochrome P-450, could also produce nuclear changes. The model used was the response of peripheral lymphocytes to blastogenic agents by studying lymphocyte sub-populations. No changes occurred in the B- and T-lymphocyte sub-populations or in the helper and suppressor sub-types. The response to the blastogenic agents, phytohaemagglutinin and purified protein derived from mycobacteria, did not change significantly from before entry into the study to the follow-up (18.1 +/- 2.9 months). All control patients (n = 44 patient pairs) had slightly greater mitogenic activity compared with patients treated with spironolactone; no difference was found when control patients were compared with patients given potassium canrenoate. The difference between spironolactone and potassium canrenoate might be due to toxicity caused by the thio group of spironolactone. Overall, however, both drugs may be regarded as safe, in terms of effects on lymphatic tissue, occurring during the course of cirrhosis.

B-Lymphocytes↗