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Biomedical subjects

R Corrocher

Publications and source records attributed to R Corrocher.

At least 37 records · Page 2Linked to original sources
PubMed1995

Omega-3 polyunsaturated fatty acid supplements and ambulatory blood pressure monitoring parameters in patients with mild essential hypertension.

OBJECTIVE: To evaluate the effects of low doses of omega-3 polyunsaturated fatty acids on ambulatory blood pressure monitoring parameters in a group of mild essential hypertensives. PATIENTS: We studied 24 consecutive essential hypertensive patients from our outpatient clinic with mild hypertension (diastolic blood pressure < or = 105 mmHg), no previous treatment for 4 weeks at least and no other disease. METHODS: After a 3-month run-in period, the patients entered an intervention phase and were given 3 g omega-3 polyunsaturated fatty acids (85% eicosapentaenoic and docosahexaenoic acid concentrate) daily for 4 months; this phase was followed by a 4-month washout period. Ambulatory blood pressure monitoring was performed at the end of each phase; erythrocyte membrane fatty acids were assessed to check compliance. RESULTS: After 4 months of treatment, erythrocyte omega-3 polyunsaturated fatty acids significantly increased but average systolic and diastolic blood pressure and the heart rate did not significantly change; no significant variations were recorded in blood pressure or heart rate variability (assessed as blood pressure and heart rate SD) nor in the diurnal blood pressure rhythm. After washout, a significant decrease was observed in erythrocyte omega-3 polyunsaturated fatty acids but the ambulatory blood pressure monitoring parameters were not substantially modified. CONCLUSIONS: The present data show that low doses of omega-3 polyunsaturated fatty acids as a single treatment are not effective in lowering blood pressure or the heart rate in mild essential hypertensive patients, despite a significant change in fatty acid cell membrane composition. Nor does this treatment seem likely to affect blood pressure variability or the diurnal rhythm.

Blood Pressure↗
PubMed1994

Oxidative damage and erythrocyte membrane transport abnormalities in thalassemias.

Oxidative damage induced by free globin chains has been implicated in the pathogenesis of the membrane abnormalities observed in alpha and beta thalassemia. We have evaluated transport of Na+ and K+ in erythrocytes of patients with thalassemias as well as in two experimental models that use normal human red blood cells, one for alpha thalassemia (methylhydrazine treatment, alpha thalassemia like) and one for beta thalassemia (phenylhydrazine treatment, beta thalassemia like). With the exception of the Na-K pump, similar alterations in membrane transport were observed in thalassemia and thalassemia-like erythrocytes. These were: increased K-Cl cotransport, Na-Li countertransport and reduced Na-K-Cl cotransport. The Na-K pump was reduced in thalassemia-like cells, whereas it was increased in severe alpha thalassemia and in beta thalassemia cells. The increased K-Cl cotransport activity could be observed in light and dense fractions of beta-thalassemic cells. K-Cl cotransport in thalassemic and thalassemia-like erythrocytes was partially inhibited by [(dihydro-indenyl) oxy] alkanoic acid and completely abolished by dithiothreitol. Thus, oxidative damage represents an important factor in the increased activity of the K-Cl cotransport observed in thalassemias, and of the K+ loss observed in beta-thalassemia erythrocytes.

Chlorides↗
PubMed1994

Decreased activity of scavenger enzymes in human hepatocellular carcinoma, but not in liver metastases.

To investigate the role of oxygen free radicals in hepatocellular carcinoma we assayed tissue scavenger enzymes (superoxide dismutase and selenium-dependent glutathione peroxidase) in liver homogenate, plasma concentrations of vitamins A and E and the serum selenium level from 19 control patients, 23 cases of hepatocellular carcinoma and 18 cases of metastases to liver from different carcinomas. In hepatocellular carcinoma tissue the enzyme activities were all significantly lower than in control liver and in metastases-bearing liver; the enzyme activities of the latter tissues were not different from control liver. In contrast, normal liver adjacent to the hepatocellular carcinoma had decreased activity of superoxide dismutase. Serum selenium concentrations were significantly decreased in patients with hepatocellular carcinoma and those with liver metastases, while vitamin A was significantly decreased only in the former. These findings suggest that hepatocellular carcinoma develops in liver with severe impairment of cellular antioxidant systems, since, in patients with liver metastases from different cancers, despite low selenium concentrations, cellular scavenger enzymes have normal activities.

Adult↗
PubMed1994

Factors affecting the thiobarbituric acid test as index of red blood cell susceptibility to lipid peroxidation: a multivariate analysis.

The relationship between formation of thiobarbituric acid reactive substances (TBARS) in red blood cells (RBC) after exposure to H2O2 and factors potentially able to modulate it was investigated by a multivariate analysis in 92 healthy volunteers. The independent covariates considered were: RBC membrane fatty acids and cholesterol, RBC antioxidant enzymes and zinc, plasma vitamins A and E and serum selenium, zinc and copper. The stepwise multiple-linear-regression analysis revealed RBC membrane fatty acids and cholesterol as predictors of a consistent proportion of the RBC-TBARS variability whereas none of the antioxidants entered the equation. The unsaturation index was the most important individual predictor; RBC-TBARS increased with increasing concentrations of total omega-3 polyunsaturated fatty acids, C 20:5 omega-3 and cholesterol, whereas they decreased with increasing concentrations of total monounsaturated fatty acids, saturated fatty acids, C 16:0 and C 18:0. It is suggested that formation of TBARS, at least in currently used conditions, reflects mainly the lipid composition of the tissue under investigation, without giving sufficient information about the status of the antioxidant defences.

Adult↗
PubMed1993

Activation of K+/Cl- cotransport in human erythrocytes exposed to oxidative agents.

Activation of K+/Cl- cotransport was studied after exposure of normal human erythrocytes to the oxidative action of acetylphenylhydrazine (APH), menadione sodium bisulfite (MSB), hydrogen peroxide (H2O2) or phenazine metasulfate (PMS). In order to better define the relative contributions of K+/Cl- cotransport on ouabain and bumetanide-resistant (OBR) K+ efflux induced by oxidation, we used (dihydroindenyl)oxyalkanoic acid (DIOA) and carbocyanine as specific inhibitors, respectively, of cotransport system and Ca(2+)-activated K+ channel. APH, MSB and - to much less extent - H2O2 promoted a K+ efflux pathway with features corresponding to those of K+/Cl- cotransport. This pathway showed: (i) kinetics of efflux compatible with a specific cation transport system; (ii) requirement for chloride anion; (iii) resistance to ouabain, bumetanide and carbocyanine inhibition; (iv) stimulation by hypotonic challenge; (v) susceptibility to inhibition by DIOA. Dithiothreitol (DTT) or 2-mercaptoethanol (2-ME) decreased K+/Cl- cotransport activation, suggesting that oxidative mechanisms affected crucial SH groups of the transporter. These data suggest that oxidation represents a factor capable of modulating activation of K+/Cl- cotransport. Its possible contribution in situations with high oxidative risk, such as sickle-cell anaemia or beta thalassemia, is discussed.

Biological Transport↗
PubMed1993

alpha-Interferon in the treatment of chronic viral hepatitis: effects on fibrogenesis serum markers.

Forty patients with chronic viral hepatitis or active cirrhosis (33 anti-HCV positive) entered a recombinant human alpha 2A interferon randomized trial. Twenty-one subjects were treated with 6 million units (MU) three times per week for 6 months. Nineteen were not treated. Six months later in 12 patients of the treated group (60% of the evaluable 20) with normalized serum aminotransferases levels (responders), fibrogenesis serum markers (NPIIIP and laminin) were significantly lower than baseline. In the untreated patients and in non-responders NPIIIP and laminin were unchanged. Semi quantitative histological evaluation (allotting scores for inflammation, necrosis and fibrosis) confirmed a significant improvement of necro-inflammation in the responders. These data suggest that alpha-IFN treatment may decrease stimuli for fibrogenesis by reducing liver inflammation and necrosis, thus preventing evolution to cirrhosis.

Adult↗
PubMed1993

Low platelet glutathione peroxidase activity and serum selenium concentration in patients with chronic renal failure: relations to dialysis treatments, diet and cardiovascular complications.

1. Selenium status was investigated in patients with chronic renal failure, with special regard to its relations to the dialysis treatments, dietary habits and clinical signs of atherosclerosis. 2. Serum selenium concentration and platelet glutathione peroxidase activity were measured in 45 patients with chronic renal failure subdivided into three groups according to the type of treatment: 15 non-dialysed, 15 on haemodialysis, 15 on continuous ambulatory peritoneal dialysis. A 7-day diet history was carried out in all patients. Seventeen of the patients with chronic renal failure had clinically overt cardiovascular disease. Forty-five age-matched healthy subjects were considered as controls. 3. Both serum selenium concentration and platelet glutathione peroxidase were significantly reduced in all patients with chronic renal failure compared with control subjects; a direct and significant correlation was found between the two parameters. No differences in selenium status were observed among the non-dialysed, haemodialysis and continuous ambulatory peritoneal dialysis groups. No correlation between total calorie or protein intakes and selenium indices were observed. The chronic renal failure patients with cardiovascular complications showed a further significant reduction in both serum selenium concentration and platelet glutathione peroxidase activity as compared with the patients without cardiovascular complications; these two groups were similar with respect to the other well-known cardiovascular risk factors (age, smoking, plasma lipids, hypertension, body mass index). 4. It is concluded that a low selenium concentration is present in chronic renal failure, which is independent of dialysis and is accompanied by biological repercussion in terms of reduced platelet glutathione peroxidase activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Potassium loss and cellular dehydration of stored erythrocytes following incubation in autologous plasma: role of the KCl cotransport system.

We studied the regulation of cell volume and cation content in erythrocytes stored at 4 degrees C under blood bank conditions for various lengths of time and subsequently incubated in autologous plasma at 37 degrees C for 4 or 24 h. Cell swelled during storage at 4 degrees C whereas marked K+ loss and cell shrinkage were observed when erythrocytes were incubated at 37 degrees C in autologous plasma. The cell shrinkage was inhibited only by the K+ Cl- cotransport-specific inhibitor, [(dihydroindenyl)oxy] alkanoic acid, and not by other specific inhibitors of cation transport systems such as ouabain (Na(+)-K+ ATPase pump), bumetanide (Na(+)-K(+)-Cl- cotransport) or carbocyanine (Ca+(+)-activated K+ channel). Acidification and swelling of the erythrocytes are well known to be able to activate the K+ Cl cotransport; such conditions, which were demonstrated to occur during the storage, could lead to activation of the K+ Cl- cotransport in reinfused cells. These data strongly support the evidence that K+ Cl- cotransport plays a role in K+ loss and dehydration of stored erythrocytes, when incubated in autologous plasma.

Adult↗
PubMed1993

[Effectiveness of loratadine vs. placebo in the treatment of urticaria-angioedema syndrome in patients with food allergy].

Loratadine is a new, highly selective, non sedating, H 1-receptor antagonist, without central nervous system activity. In a randomized double-blind, crossover study, we evaluated the effects of loratadine and placebo administered once daily in 184 food intolerant patients affected by urticaria-angioedema. The difference between loratadine and placebo treatment was significant in relieving symptoms. Adverse reactions reported in the treatment were mild, in fact somnolence was reported by 3.4%, dry mouth by 2.2% of patients.

Adult↗
PubMed1992

Red blood cells and platelet membrane fatty acids in non-dialyzed and dialyzed uremics.

Three groups of patients with chronic renal failure (CRF), 16 non-dialyzed, 16 undergoing haemodialysis (HD), 16 undergoing continuous ambulatory peritoneal dialysis (CAPD), and 48 controls were examined. We analyzed the fatty acid composition in membranes from erythrocytes and platelets and the platelet malondialdehyde (MDA) production as an index of thromboxane metabolism. Marked differences in erythrocytes fatty acid composition were observed between patients with CRF and controls and, particularly, among the three groups of patients with CRF. Patients on CAPD were characterized by an increase in oleic acid, while haemodialyzed had a marked increase in arachidonic acid. Platelet fatty acid composition showed similar differences, suggesting a 'systemic' membrane abnormality. Platelet MDA was increased in haemodialyzed and positively correlated with the platelet arachidonate content.

Adult↗
PubMed1992

Effects induced by olive oil-rich diet on erythrocytes membrane lipids and sodium-potassium transports in postmenopausal hypertensive women.

Since we have observed that monounsaturated fatty acids (MUFA) enriched diet modifies red cell membrane lipids and cation transport systems in normotensive subjects, we similarly evaluated a group of hypertensive patients undergoing an analogous dietary modification. In a group of 18 moderately hypertensive women, the diet was supplemented for two months with olive oil (about 45 g/day), which replaced an equal amount of seasoning fats. Before and after this period, red cell fatty acid composition was evaluated by gas-chromatography in order to verify diet compliance: a significant increase in oleic acid was observed, while the content of saturated and polyunsaturated fatty acids remained unchanged. After olive oil, maximal rates of Na-K pump (5580 +/- 329 vs 6995 +/- 390, p less than 0.001) and Na-K cotransport (Na-COT 544 +/- 52 vs 877 +/- 46, p less than 0.001: K-COT 790 +/- 76 vs 1176 +/- 66, p less than 0.001), cell Na content (9.58 +/- 0.4 vs 10.61 +/- 0.6, p less than 0.03) and passive permeability for Na (936 +/- 74 vs 1836 +/- 102, p less than 0.001) rose significantly. Although the reduction in maximal rate of the Li-Na CT after olive oil was not significant, it was the only cation transport parameter being correlated with the variations of membrane lipids, namely negatively with UFA (r = -0.528, p less than 0.05) and positively with SFA (r = 0.482, p less than 0.005). The change in maximal rate of Li-Na CT was also correlated with the variation of systolic and diastolic BP (r = 0.50, p less than 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1992

[Food allergy and asthma].

The prevalence of asthma in patients suffering from food allergy or food intolerance had been studied in 1339 subjects. Of them, 165 patients (12.8%) were affected by asthma. However only 77 (5.7%) had positive prick tests for food antigens and 52 of these have a significant benefit when a suitable oligoallergenic diet was introduced. 35 out of patients were positively tested with a double-blind food challenge. The most frequent food antigen involved were milk and its derivatives and cereals, but some importance have also the additives to the food. In conclusion, in our patients suffering from food allergy or food intolerance asthma was present in 12.8% of the cases, but in only 77 (5.7%) the symptoms might be due to diet. When tested with oligoallergenic diet or with food challenge the percentage of positivity fall to 3.9% and 2.6% respectively.

Adult↗
PubMed1992

Red blood cell susceptibility to lipid peroxidation, membrane lipid composition, and antioxidant enzymes in continuous ambulatory peritoneal dialysis patients.

OBJECTIVE: To investigate the overall susceptibility of red blood cells (RBC) to lipid peroxidation from patients on continuous ambulatory peritoneal dialysis (CAPD). METHODS: The following parameters were measured: RBC malondialdehyde (MDA) production after oxidative stress with H2O2, RBC antioxidant enzymes glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), and RBC membrane lipid composition. The levels of plasma vitamin E and serum selenium were also assayed. PATIENTS: Eleven patients on continuous ambulatory peritoneal dialysis. Twenty-one healthy blood donors of similar age were used as normal controls. RESULTS: The MDA formation after H2O2 stimulation was normal in CAPD patients (0.79 +/- 0.1 mumol/gHb versus 0.78 +/- 0.1 in the control group). RBC from CAPD patients also showed a normal SOD activity, a more than adequate vitamin E status, and a peculiar pattern of membrane lipids, with reduced polyunsaturated fatty acids (p less than 0.001) and increased monounsaturated fatty acids (p less than 0.001). Both RBC GSH-Px activity, a selenium-dependent enzyme, and serum selenium levels were significantly lower in CAPD patients, and a significant positive correlation (r = 0.68; p less than 0.02) between the two parameters was found. CONCLUSIONS: This study found a normal sensitivity to oxidant stress in RBC from a group of CAPD patients, despite an impaired GSH-Px activity. The peculiar lipid pattern of RBC membrane, characterized by reduced PUFA and increased MUFA content, may contribute, in addition to adequate SOD activity and vitamin E status, to normal RBC lipid peroxidation.

Aged↗
PubMed1991

Erythrocyte and platelet fatty acids in retinitis pigmentosa.

The fatty acid composition and the glutathione-peroxidase activity (GSH-Px) of erythrocytes and platelets, the production of malondialdehyde (MDA) by platelets and the activity of the main systems of transmembrane cation transport in erythrocyte have been studied in 12 patients (5 males and 7 females) affected by retinitis pigmentosa (RP). A remarkable increase of saturated fatty acids (SFA), particularly of stearic acid (C18:0), has been noted in these patients. The reduced unsaturated/saturated fatty acids ratio (PUFA/SFA) observed in both erythrocytes and platelets and the decrease of arachidonic acid in platelets may depend by an active peroxidation process as documented by the increase of MDA. Platelet glutathione-peroxidase (PTL-GSH-PX) and plasma retinol were in the normal range, whereas erythrocyte glutathione-peroxidase (E-GSH-PX), MDA and plasma alfa-toco-pherol were increased in patients with RP. The activities of Na(+)-K+ pump, cotransport and Na(+)-Li+ countertransport were normal in RP erythrocytes.

Adult↗