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D Cottalasso

Publications and source records attributed to D Cottalasso.

67 records · Page 4Linked to original sources
PubMedDate not supplied

Scanning force microscopy reveals structural alterations in diabetic rat collagen fibrils: role of protein glycation.

BACKGROUND: The main functional property of collagen is to provide a supporting framework to almost all tissues: the effects of non-enzymatic glycation on this protein are deleterious and in diabetes mellitus contribute to the mechanism of late complications. The aim of this work is to provide evidence by scanning force microscopy of modifications in collagen structure caused by high glucose concentration, in vivo and in vitro, and to correlate the data with markers of non-enzymatic glycation. METHODS: Tendon fibrils were obtained from the tails of 8-month-old rats (BB/WOR/MOL¿BB) which developed diabetes spontaneously at least 12 weeks before they were killed, and from diabetes-resistant rats of the same strain (BB/WOR/MOL¿WB). A scanning force microscope (SFM; Nanoscope III) equipped with a Contact Mode Head was used for imaging. Band interval, diameter and depth of D-band gap were measured in non-diabetic and diabetic tail tendon fibrils and in fibrils incubated with glucose (0.5 M for 2 weeks). Fructosamine was determined in the tendon fibrils by a colorimetric method and pentosidine was evaluated in acid-hydrolyzed samples by coupled reverse phase-ionic exchange column HPLC. RESULTS: Incubated fibrils revealed modifications in radius (228+/-5 nm) and gap depth (3.65+/-0.10 nm) that closely reproduce diabetes-induced damage (236+/-3 and 3.20+/-0.04 nm respectively) and were significantly different from the pattern seen in non-diabetic fibrils (151+/-1 and 2.06+/-0.03 nm; p<0.001). Both fructosamine and pentosidine were higher in diabetic (3.82+/-1.43 nmol/mg and 2.23+/-0.24 pmol/mg collagen respectively) and in glucose-incubated fibrils (9.27+/-0.55 nmol/mg and 5.15+/-0.12 pmol/mg collagen respectively) vs non-diabetic tendons (1.29+/-0.08 nmol/mg and 0.88+/-0.11 pmol/mg collagen respectively; p<0.01); during the time course of incubation, an early increase in fructosamine was seen, whereas pentosidine increased later. The D-band parameter was similar in all three groups, indicating that axial organization is not modified by non-enzymatic glycation. CONCLUSION: This is the first description obtained with SFM of diabetes-induced ultrastructural changes in collagen fibrils. Moreover, the data presented are consistent with the concept that chronic exposure of collagen to glucose in vivo or in vitro leads to similar structural modifications in collagen fibrils, probably through crosslinks. The correlation between morphologic parameters and both markers of glycation provides strong evidence for a crucial role of this non-enzymatic modification.

Animals↗
PubMedDate not supplied

Orthotopic liver transplantation in a young adult (33 years old) using an 84-year-old donor.

Shortage of liver donors and the increasing number of patients on the waiting list for liver transplantation have led to a widening of the definition of liver donor suitability. Although the age limit for liver donors is controversial, current opinion is towards using liver allografts from donors older than 60 years. However, to date only a few cases that showed a good performance of liver graft by donors older than 60 years have been described. In this case report, orthotopic liver transplantation in a 33-year-old patient who received a graft from an 84-year-old donor is presented. A careful evaluation of the conventional donor-related risk factors (hemodynamics, hepatic function and histologic features) was carried out. Moreover, free radical scavenger glutathione was measured before cold ischemia and at the time of reperfusion in hepatic biopsies. After a 1-year follow-up, the recipient exhibits good general conditions and normal liver function values.

Adult↗
PubMedDate not supplied

[Toxicity of 4-chloro-2-nitroaniline and 2-chloro-4-nitroaniline to isolated rat hepatocytes].

The toxicity of 4-chloro-2-nitroaniline (4C2NA) and 2-chloro-4-nitroaniline (2C4NA) was investigated on isolated rat hepatocytes following 1-3 hours of exposure to 0.2 and/or 2 mM of these xenobiotics. The higher of the two concentrations appeared to induce a statistically significant loss of cellular viability (p less than 0.01 compared to control), judged by Trypan Blue staining, after 3 hours of incubation with these substances means = 58, SD = 7%; and means = SD = 7%; for 4C2NA and 2C4NA, respectively). Furthermore, both chloronitroanilines produced an hepatocellular and microsomal damage demonstrated by conspicuous changes in LDH and G-6-Pase activities (p less than 0.01). The exposure to 2 mM of both 4C2NA and/or 2C4NA produced a marked depletion of the intracellular pool of GSH after 3 hours (13 mM/10(6) and 10 mM/10(6) cells, respectively; p less than 0.01). Thus it seems possible that 2C4NA may induce a more severe cellular damage than that induced by 4C2NA.

Aniline Compounds↗
PubMedDate not supplied

Study of proteins, phospholipids and cholesterol of rat bile during chronic drainage.

Glycerophospholipids, cholesterol and proteins of rat bile were analyzed at different time-intervals during the bile duct cannulation over a period of 24 hr, to study a possible association between the secretion of these bile components. Glycerophospholipids and cholesterol decreased between the 16th-24th hrs, then rose again, showing a bile acid synthesis dependence. In contrast, during the entire collection period, protein concentration was normal. On gel electrophoresis bile proteins give a spectrum of fifteen discrete bands, three of them being Sudan black positive. Some, but not all bile protein bands, show a pattern similar to serum proteins both by means of SDS disc electrophoresis and of immunological techniques. According to the bile composition in GPL and cholesterol and the presence in bile of lipoproteins with SDS electrophoresis migration superimposable to apo-A-IV of serum high density lipoproteins, the following hypothesis is suggested to explain the origin and pathway that some fractions of bile can follow to reach biliary canalicula: some serum or membrane components (that is GPL, cholesterol and possibly apo-A-IV) might insert themselves into the outer leaflet of hepatocyte plasmamembranes at the sinusoidal side; from here they may slip over the inner plasmamembrane monolayer, through the junctions, to the canalicular region of the membrane to give rise, by the action of bile salts, to micelles of bile, together with components coming from other subcellular compartments, following different pathways.

Animals↗
PubMedDate not supplied

[CoQ10 blood levels and erythrocyte concentration of GSH in ischemic heart patients during exercise test (effects of vitamin E)].

During exercise there is an increase of oxygen consumption with production of superoxide anion. Tocopherols and ubiquinones are intrinsic lipid components involved in antioxidant protection and also glutathione reduced is an important water soluble antioxidant. The authors take into consideration 28 patients with ischemic heart disease coming in a rehabilitation center. In a group of 14 of them we studied the effects on the exercise ergonometer test of administration of 1200 mg of tocopherol on the behaviour of ubiquinone plasmatic levels and GSH. In this group CoQ10 after exercise increase significantly (0.762 SD 0.134 g/ml before vs 0.827 SD 0.89 after). GSH doesn't increase after (2.5 SD 0.459 mM/l vs 2.492 SD 0.457). In the group of patients without tocopherol after exercise CoQ10 decrease significantly (-39%) and also GSH has the same behaviour (-15%). Our study shows that the administration of tocopherol prevents lipoperoxidation occurring during exercise test.

Adult↗
PubMedDate not supplied

Effects of simvastatin on liver and plasma levels of cholesterol, dolichol and ubiquinol in hypercholesterolemic rats.

Increased levels of blood cholesterol are considered as a major factor in the development of atherosclerosis. Simvastatin, a drug which blocks hydroxymethylglutaryl coenzyme A reductase (HMGCoAR), reduces plasma cholesterol and increases HDL-cholesterol in rats fed a hypercholesterolemic diet. Moreover, simvastatin produces a significant decrease of ubiquinol and dolichol in plasma and in liver.

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