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Biomedical subjects

M Viti

Publications and source records attributed to M Viti.

At least 37 records · Page 2Linked to original sources
PubMed1984

Cooperative effect of exogenous heparin-like compounds and secreted glucocorticoid-induced inhibitor on plasminogen activator in 3T3 cell cultures.

Balb/c 3T3 cultures grown in the absence of serum release both plasminogen activator and plasminogen activator inhibitor in the culture medium. Cellular transformation with SV-40 virus increased the level of the activator, whereas dexamethasone increased the level of the inhibitor. Heparin added to the medium potentiated the glucocorticoid-induced inhibitory activity, strongly decreasing or completely abolishing the activity of plasminogen activator. Heparin sulfate showed similar effects to heparin, although at higher concentrations. It is suggested that heparin-like compounds are involved in the regulation of plasminogen activator, acting as inhibitory cofactors.

Animals↗
PubMed1984

Structure and properties of an under-sulfated heparan sulfate proteoglycan synthesized by a rat hepatoma cell line.

A rat hepatoma cell line was shown to synthesize heparan sulfate and chondroitin sulfate proteoglycans. Unlike cultured hepatocytes, the hepatoma cells did not deposit these proteoglycans into an extracellular matrix, and most of the newly synthesized heparan sulfate proteoglycans were secreted into the culture medium. Heparan sulfate proteoglycans were also found associated with the cell surface. These proteoglycans could be solubilized by mild trypsin or detergent treatment of the cells but could not be displaced from the cells by incubation with heparin. The detergent-solubilized heparan sulfate proteoglycan had a hydrophobic segment that enabled it to bind to octyl-Sepharose. This segment could conceivably anchor the molecule in the lipid interior of the plasma membrane. The size of the hepatoma heparan sulfate proteoglycans was similar to that of proteoglycans isolated from rat liver microsomes or from primary cultures of rat hepatocytes. Ion-exchange chromatography on DEAE-Sephacel indicated that the hepatoma heparan sulfate proteoglycans had a lower average charge density than the rat liver heparan sulfate proteoglycans. The lower charge density of the hepatoma heparan sulfate can be largely attributed to a reduced number of N-sulfated glucosamine units in the polysaccharide chain compared with that of rat liver heparan sulfate. Hepatoma heparan sulfate proteoglycans purified from the culture medium had a considerably lower affinity for fibronectin-Sepharose compared with that of rat liver heparan sulfate proteoglycans. Furthermore, the hepatoma proteoglycan did not bind to the neoplastic cells, whereas heparan sulfate from normal rat liver bound to the hepatoma cells in a time-dependent reaction. The possible consequences of the reduced sulfation of the heparan sulfate proteoglycan produced by the hepatoma cells are discussed in terms of the postulated roles of heparan sulfate in the regulation of cell growth and extracellular matrix formation.

Animals↗
PubMed1981

Binding of the basement-membrane glycoprotein laminin to glycosaminoglycans. An affinity-chromatography study.

The binding of the basement-membrane glycoprotein laminin to glycosaminoglycans (aggregating and non-aggregating subsets of heparan sulphates and dermatan sulphates, as well as heparin, chondroitin sulphates and hyaluronic acid) was studied by affinity chromatography. Partially periodate-oxidized chains of glycosaminoglycans were coupled to adipic acid dihydrazide-substituted agarose. Co-polymeric glycosaminoglycans reveal high affinity for laminin, whereas hyaluronic acid does not. Competitive-release experiments indicate that glycosaminoglycans share a common binding site on the laminin molecule.

Animals↗
PubMed1980

[Postoperative acute pancreatitis (PAP). Direct personal experience].

Eight different cases of APP observed after intervents made near the pancreas (partial gastrectomy for ulcer, papillosphincteroplasty, DCP) are presented. The clinical stage, the therapeutic attempts, the results are studied. The clinical stage, the therapeutic attempts, the results are studied. In order to value the role of the pancreatic trauma in causing the APP the Authors have checked in addition 14 cases in which a direct action on the pancreas was present. In these cases noticeable amylasemic increases have not been observed except one cases of APP after DCP. Hypothesizing the role of a duodenal hyperpressure in causing the reflux of duodenal juice into the Wirsung then in causing an APP, the Authors report the results obtained after the introduction of a catheter into the duodenum in order to make it empty untily the renewal of peristalsis, during the papillosphincteroplasty and partial gastrectomy for ulcer. The Authors suggest that the duodenal emptying could be a method to prevent the APP. The prevention by the usually adopted drugs as aprotininum and glucagonum was ineffective, as well as other surgical techniques. High mortality: 5 cases on 8.

Adult↗
PubMed1980

[Study of postoperative amylasemia. Its diagnostic value in postoperative acute pancreatitis (PAP)].

A study of the postoperative amylasemia levels on 375 different intervents is presented. Three different behaviours have been observed: 1) in 44 cases there has been a rapid increase of the amylasemia gone on for less than 4 days without any clinical sign of pancreatitis; 2) in 6 cases the increase, sometimes less marked than the previous cases, developed and continued for longer time, showing oscillations with a slow return to the normality. At the same time there was a slow recovery in the general conditions; the cause of that has been interpreted as a pancreatic affection; 3) in 8 cases the amylasemia increase developed for many days with large and long oscillation and clinical signs of APP. The opinion of Authors is that the APP is characterised by amylasemia increases presenting large oscillations life times exceeding 4 days, and that they are joined with clinical signs of pancreatitis (pain, sickness, hypotension, ec.). The study of the amylasemia plotting is considered to be a rather good method to emphasize a pancreatic disease.

Acute Disease↗