19 research outputs found
Analisi dei ricoveri per dermatosi professionale nell'istituto di medicina del lavoro di siena nel periodo 1989-2001
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Alteration in the redox state of plasma in heart transplanted patients with moderate hyperhomocisteinemia
No full textHyperhomocysteinemia has recently been suggested to contribute to the progression of the so-called chronic rejection or cardiac allograft vasculopathy (CAV) in heart-transplant patients in which the major determinant of the increase in homocysteine (Hcy) was the progressive decline of renal function. The exact mechanisms of tissue injury by Hcy is unknown, but some aspects of its toxicity have been related to its capacity for altering the redox state of plasma and forming protein adducts by intermediate lactone. To study the relationships between Hcy levels and variations in the redox state governed by thiols, plasma levels of Hcy, cysteine, glutathione, cysteinylglycine, and corresponding disulfides and protein-mixed disulfides were evaluated in subjects with moderate hyperhomocysteinemia represented by heart-transplant patients with (HTRF) and without (HT) renal failure, as well as patients with renal failure of different origin (RF), and compared with those of a control group (C) of normal subjects matched for age and sex. Plasma levels of Hcy and the corresponding protein mixed disulfides increased progressively in HTs, Us, and HTRFs with respect to control. These changes were correlated with cysteine variations (as cystine and protein-mixed disulfides) but not with glutathione or cysteinylglycine that varied only as disulfides with a similar tendency. Moreover, an alteration in the plasma redox was evidenced by the decrease in thiol/disulfide ratios of cysteine, Hcy, and cysteinylglycine. In all groups, cysteine was directly correlated with Hcy but not with glutathione or cysteinylglycine, which in turn were correlated each other. Therefore levels of plasma cysteine were more linked to Hcy than to metabolism of glutathione. The clinical meaning of cysteine changes remains undefined and requires further study
Two sporadic cases of idiopathic multiple minute digitate hyperkeratosis
No full textMultiple minute digitate hyperkeratosis (MMDH) is a skin disease of unknown aetiology characterized clinically by multiple minute asymptomatic keratotic lesions with spiky horny projections. The disorder has been classified into early (congenital) and late (acquired) onset forms, the latter occurring as a presenting sign of concomitant inflammatory, metabolic or malignant disease. Here we report two cases of late onset MMDH without any associated patholoyg. These cases emphasize that some cases of late-onset MMDH may be idiopathic
Minor thiols cysteine and cysteinylglycine regulate the competition between glutathione and protein SH groups in human platelets subjected to oxidative stress
No full textChanges in the concentrations of protein-mixed disulfides (XS-SP) of glutathione (GSH), cysteine (CSH), and cysteinylglycine (CGSH) were studied in human platelets treated with diamide and t-BOOH in timecourse experiments (time range, 1-30 min) in order to understand the contribution of minor thiols CSH and CGSH to the regulation of glutathione-protein mixed disulfides (GS-SP). Diamide was much more potent than t-BOOH in altering the platelet thiol composition of XS-SP (threshold dose: diamide, 0.03 mM; t-BOOH, 0.5 mM) and caused reversible XS-SP peaks whose magnitude was related to the concentration of free thiols in untreated cells. Thus maximum levels of GS-SP (8 min after 0.4 mM diamide) were about 16-fold higher than those of controls (untreated platelets, GS-SP = 0.374 nmol/109 platelets), whereas those of CS-SP and CGS-SP were only 4-fold increased (untreated platelets, CS-SP = 0.112 nmol/109 platelets; CGS-SP = 0.024 nmol/109 platelets). The greater effects of diamide with respect to t-BOOH were explained on the basis of the activities of fast reactive protein SH groups for diamide and glutathione reductase (GR) and glucose-6-phosphate dehydrogenase (G-6-PDH) for t-BOOH. The addition of cysteine (0.3 mM, at 4 min) after treatment of platelets with 0.4 mM diamide increased the rate of reversal of GS-SP peaks to normal values, but also caused a relevant change in CGS-SP with respect to that of platelets treated with diamide alone. An increased γ-glutamyltranspeptidase activity was found in platelets treated with diamide. Moreover, untreated platelets were found to release and hydrolyze GSH to CGSH and CSH. Ratios of thiols/disulfides (XSH/XSSX) and activities of GR and G-6PDH were also related to a high reducing potential exerted by GSH but not by minor thiols. The lower mass and charge of minor thiols is a likely requisite of the regulation of GS-SP levels in platelets. (C) 2000 Academic Press
The use of non-invasive diagnostic techniques for the advanced diagnosis of skin cancer among agricultural workers
No full textAdministration of minor polar compound-enriched extra virgin olive oil decreases platelet aggregation and the plasma concentration of reduced homocysteine in rats
No full textWe investigated the effect of extra virgin olive oil (EVOO) on platelet aggregation and plasma concentrations of homocysteine (Hcy) redox forms in rats in relation to the minor polar compound (MPC) concentration of EVOO. We used 3 olive oil samples with similar fatty acid but different MPC concentrations: refined olive oil (RF) with traces of MPC (control oil), native EVOO with low MPC concentration (LC), and EVOO with high MPC concentration (HC) enriching LC with its own MPC. Oil samples were administered to rats by gavage (1.25 mL/kg body weight) using 2 experimental designs: acute (24-h food deprivation and killed 1 h after EVOO administration) and subacute (12-d treatment, a daily dose of oil for 12 d, and killed after 24 h of food deprivation). Platelet aggregation was induced by ADP (ex vivo tests) and a reduction in platelet reactivity occurred in cells from rats given LC in the subacute study and in cells from rats administered HC in both studies as indicated by an increase in the agonist half maximal effective concentration. HC inhibited platelet aggregation induced by low ADP doses (reversible aggregation) in cells of rats in both the acute and subacute studies, whereas LC had this effect only in the subacute experiment. Moreover, in rats administered HC in both experiments, the plasma concentration of free reduced Hcy (rHcy) was lower and Hcy bound to protein by disulfide bonds (bHcy) was greater than in RF-treated rats. bHcy was also greater in rats given LC than in RF-treated rats in the subacute experiment. Plasma free-oxidized Hcy was greater in rats given LC and HC than in those administered RF only in the subacute experiment. In conclusion, these results show that MPC in EVOO inhibit platelet aggregation and reduce the plasma rHcy concentration, effects that may be associated with cardiovascular protection. © 2008 American Society for Nutrition
A new surgical approach for the treatment of severe epithelial skin sun-induced damage
No full textBackground. Cutaneous photoageing is a complex biological process affecting all layers of the skin. Skin damage resulting from intrinsic ageing and extrinsic photoageing may trigger skin cancer. In patients with advanced photoageing and/or diffuse actinic damage, local therapy is often inadequate and the possibility of combined therapy needs to be assessed. Subjects. Here we report three cases of patients over 75 years of age with advanced diffuse epithelial skin damage of photoexposed areas consisting of several superficial actinic keratoses, ipermelanotic lesions and multiple skin cancers. Methods. Neoplastic lesions and damaged skin were removed by superficial erbium laser ablation and the epidermis reconstructed with autologous epidermal sheets expanded in vitro from healthy cells obtained from unexposed areas of the body. Results. Our initial studies show that this procedure is very effective in the short term for treating and preventing the UV-induced skin cancer and precancerous lesions, and also suggest good long-term control of the disease with very interesting aesthetic results
