PubMed Health⌕ Search

Biomedical subjects

M T Trevisan

Publications and source records attributed to M T Trevisan.

10 recordsLinked to original sources
PubMed1995

Correlations between the intensity of fMLP-dependent respiratory burst and cellular fatty acid composition in human neutrophils.

The peripheral blood neutrophils were isolated from a group of normal subjects and their fatty acid composition determined by capillary gas-chromatography. The superoxide (O2-) release by the same cell preparation in response to formyl-methionyl-leucyl-phenylalanine was also determined following cytochrome c reduction in a microplate assay. A strong negative correlation was found between C18:2 (linoleic acid) (r = 0.703, P = 0.001) and C:16:0 (palmitic acid) (r = 0.569, P = 0.009) and fMLP-stimulated O2- release, whereas C20:4 (arachidonic acid) correlated positively (r = 0.448, P = 0.048). Other fatty acids, namely C12:0, C14:0, C16:1, C18:1, C18:3, C18:4, C20:0, C20:1, C20:2, C20:5, C22:0, C22:1, C22:6, C24:0 and C26:0, were not correlated with O2-. No correlations were found between fatty acid composition and O2- release from resting cells and from cells stimulated by phorbol-myristate acetate. These results suggest that the fatty acid composition of blood neutrophils may be a critical factor determining the capability of releasing free radicals in response to formylpeptides. Moreover, since a concomitant increase of arachidonic acid and decrease of its precursor linoleic acid has been found in high-responsive neutrophils, the rate of the enzymes of the arachidonic acid biosynthetic pathway (elongases and desaturases) appear to play an important role.

Arachidonic Acid↗
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↗
PubMed1994

Selenium status, fatty acids, vitamins A and E, and aging: the Nove Study.

To investigate the relationships between aging and selenium status, vitamins A and E, and plasma and erythrocyte fatty acids, we studied 105 healthy subjects (53 women, 52 men) living in Nove, a village near Vicenza (Veneto Region, northern Italy). The subjects were distributed equally for age and sex into four groups: group 1, 20-39 y; group 2, 40-59 y; group 3, 60-75 y; and group 4, > 75 y. A careful selection of subjects to exclude those with chronic or acute diseases was obtained with the collaboration of the three general practitioners operating in Nove. Aging was associated with a progressive decrease in selenium status and in the ratio of plasma and erythrocyte polyunsaturated to saturated fatty acids (P:S). Stepwise multiple linear analysis revealed age, vitamin A, and n-6 polyunsaturated fatty acids (PUFAs) as useful predictors of a substantial proportion of the selenium variability (R = 0.618, R2 = 0.382; P < 0.001) and age and erythrocyte oleic acid as predictors of erythrocyte glutathione peroxidase variability (R = 0.413, R2 = 0.17; P < 0.001).

Adult↗
PubMed1993

Predisposition to LDL oxidation in patients with and without angiographically established coronary artery disease.

Oxidative modification of low density lipoprotein (LDL) may play an important role in the mechanism of atherosclerotic damage to blood vessels. In the present study the LDL isolated from the plasmas of 73 coronary artery disease (CAD) patients, 28 valvular heart disease (VHD) patients, 59 subjects affected by type IIa hyperlipoproteinemia and 71 controls was oxidatively modified by incubation with copper ions. In 15 CAD and 15 Type IIa patients and 15 controls the LDL chemical composition and polyunsaturated fatty acid (PUFA) content were also measured. Differences in the LDL susceptibilities to lipid peroxidation were studied by measuring the changes of fluorescence intensity. The lag phase in the CAD patients was found to be significantly lower than in the VHD and controls (P < 0.001). The lag phase in the type IIa patients was significantly higher than in the CAD patients (P < 0.01), and significantly lower than the VHD and controls (P < 0.01). The LDL isolated from the type IIa patients had an increase in the relative content of free and esterified cholesterol (P < 0.05), while the CAD patients had a decrease in the relative content of free cholesterol (P < 0.05), and an increase in the relative content of protein (P < 0.05). The lowest value of the LDL cholesterol to protein ratio and LDL size, was found in the CAD patients (P < 0.05). When expressed in micrograms/mg LDL cholesterol, the concentration of the LDL PUFAs was significantly higher in the CAD group than in the others (P < 0.05). The LDL alpha-tocopherol concentration was quite similar in the different groups.(ABSTRACT TRUNCATED AT 250 WORDS)

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

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↗
PubMed1990

Transmembrane cation fluxes and fatty acid composition of erythrocytes in psoriatic patients.

Cation transport systems and lipid composition of erythrocyte membrane were studied in 27 psoriatic patients and in 34 healthy individuals. Whereas intracellular Na and K content, Na- and K-passive permeability and Li-Na countertransport of psoriatics did not show any statistical difference from normals, the Na/K ATPase pump activity was significantly higher and Na-K cotransport was significantly lower. Membrane lipid composition of psoriatics was different from normals: an increase in arachidonic acid and in unsaturated (poly- and total unsaturated) fatty acid content was found. A positive correlation was demonstrated between unsaturated/saturated fatty acid ratio and Na/K ATPase pump activity. These results demonstrate an alteration of erythrocyte Na/K ATPase pump and Na-K cotransport in psoriasis. These alterations of cation transport are associated with a perturbation of membrane fatty acid composition which appears a widespread phenomenon in cells of psoriatic patients.

Adult↗
PubMed1990

Cell membrane lipid composition in CAPD patients.

We analyzed the erythrocyte membrane lipid composition in 11 non-diabetic CAPD patients on treatment for 3-78 months and in a control group of 12 subjects. The mean total values of both saturated fatty acids and unsaturated fatty acids were not statistically different in CAPD patients and in controls but the composition of fatty acids of in cell membranes was altered. In fact, CAPD patients had a higher percentage of monounsaturated fatty acids and a lower percentage of polyunsaturated fatty acids than controls. This increase MUFA/PUFA ratio might reflect either a preferential cell membrane uptake of MUFA or a relative PUFA deficiency due to an increased lipid peroxidation.

Aged↗