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L Masana

Publications and source records attributed to L Masana.

At least 37 records · Page 2Linked to original sources

[North and south].

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Cardiovascular Diseases↗

Hepatic production of apolar aldehydes in rats with carbon tetrachloride-induced cirrhosis.

The aim of this study was to identify apolar aldehydes in liver homogenates from rats with CCl4-induced cirrhosis and, as a corollary, the antioxidant effect of zinc administration. The study was performed in five control rats and in ten cirrhotic rats which were further sub-divided into two groups to receive either a standard diet or one supplemented with zinc. The percentage of hepatic fibrosis, plasma malondialdehyde concentration and alanine aminotransferase activity were measured as well as the following aldehydes: hexanal, octanal, decanal, 2-hexenal, 2-octenal, 2-nonenal, 2,4-heptadienal and 2,4-decadienal. Of the 10 cirrhotic rats, 4 had elevated concentrations of the highly toxic 2,4-dialkenals which coincided with a higher percentage of fibrosis and plasma alanine aminotransferase activity. These aldehydes were not observed in the control group. Zinc administration was associated with a reduction of the hepatic malondialdehyde concentration and an amelioration on the degree of hepatic injury. In conclusion, this study demonstrates the presence of the highly toxic 2,4-dialkenals in hepatic tissue of rats whith CCl4-induced cirrhosis. Results obtained would suggest that these particular aldehydes may be related to the severity of the hepatic injury.

Aldehydes↗

A comparison of lifestyle, genetic, bioclinical and biochemical variables of offspring with and without family histories of premature coronary heart disease: the experience of the European Atherosclerosis Research Studies.

BACKGROUND: Lifestyle, genetic, bioclinical and biochemical factors of European university students aged 18-26 years, with and without documented paternal histories of premature coronary heart disease, have been compared in the European Atherosclerosis Research Studies (EARS) I and II. OBJECTIVE: To highlight consistencies and inconsistencies between findings in the two studies. METHODS: All measurements were made according to strict protocols, by trained technicians using validated methods. The results for men in EARS I are compared with those from EARS II which was confined to men. RESULTS: In both studies we found no differences between cases and controls in lifestyle factors and bioclinical factors except that controls were taller. We found inconsistent differences between obesity indices and antecedents of arterial hypertension. In both studies we found consistent differences between cases and controls in levels of total cholesterol and apolipoprotein B, both levels being higher in cases. The lack of any difference between levels of high-density lipoprotein cholesterol and apolipoprotein A1 was also found consistently. Inconsistent differences were found for levels of triglycerides and apolipoprotein E. For most of the candidate genes that were studied, no differences between cases and controls were found, but different polymorphisms were associated with levels of lipids, apoproteins and fibrinogen independently of case-control status. Some of these associations were potentiated by lifestyle factors. The interaction between genetic and environmental factors is further illustrated with results from the association of apolipoprotein E polymorphism with the level of apolipoprotein B and a variety of other determinants of apolipoprotein B level. CONCLUSIONS: In the EARS studies a documented family history of premature coronary heart disease was mainly expressed in terms of biochemical factors that are determined both by nature and by nurture.

Adolescent↗

Vitamin A is linked to the expression of the AI-CIII-AIV gene cluster in familial combined hyperlipidemia.

There is growing evidence of the capacity of vitamin A to regulate the expression of the genetic region that encodes apolipoproteins (apo) A-I, C-III, and A-IV. This region in turn has been proposed to modulate the expression of hyperlipidemia in the commonest genetic form of dyslipidemia, familial combined hyperlipidemia (FCHL). The hypothesis tested here was whether vitamin A (retinol), by controlling the expression of the AI-CIII-AIV gene cluster, plays a role in modulating the hyperlipidemic phenotype in FCHL. We approached the subject by studying three genetic variants of this region: a C1100-T transition in exon 3 of the apoC-III gene, a G3206-T transversion in exon 4 of the apoC-III gene, and a G-75-A substitution in the promoter region of the apoA-I gene. The association between plasma vitamin A concentrations and differences in the plasma concentrations of apolipoproteins A-I and C-III based on the different genotypes was assessed in 48 FCHL patients and 74 of their normolipidemic relatives. The results indicated that the subjects carrying genetic variants associated with increased concentrations of apoA-I and C-III (C1100-T and G-75-A) also presented increased plasma concentrations of vitamin A. This was only observed among the FCHL patients, which suggested that certain characteristics of these patients contributed to this association. The G3206-T was not associated with changes in either apolipoprotein concentrations or in vitamin A. In summary, we report a relationship between genetically determined elevations of proteins of the AI-CIII-AIV gene cluster and vitamin A in FCHL patients. More studies will be needed to confirm that vitamin A plays a role in FCHL which might also be important for its potential application to therapeutical approaches.

Adult↗

Effect of malabsorption on nutritional status and resting energy expenditure in HIV-infected patients.

OBJECTIVE: To assess the influence of malabsorption on nutritional status and energy expenditure in patients at different stages of HIV infection. DESIGN AND METHODS: Fifty HIV patients were classified into three groups: Group 1, HIV asymptomatic patients (n=17); Group 2, AIDS without opportunistic infection (n=16); Group 3, AIDS patients with active infection (n=17). Clinically-healthy subjects (n=19) were used as controls. Parameters measured were: anthropometry, body composition by tetrapolar bioelectrical impedance; resting energy expenditure (REE) by open-circuit indirect calorimetry; malabsoption by D-xylose absorption and triolein breath tests. RESULTS: Malabsorption (defined as abnormality of xylose and/or fat absorption test) was found in 34 (68%) of patients: 9 (53%) Group 1; 11 (69%) Group 2; 14 (82%) Group 3. Twenty-seven (54%) had sugar malabsorption and 21 (42%) fat malabsorption. A significant relationship was observed between malabsorption and weight loss. REE measured was significantly lower in malabsorptive patients than in non-malabsorptive patients and controls (6006.3+/-846.5 versus 6443.4 + 985.5 versus 6802.1+/-862.7 kJ/day, respectively; P < 0.05). The REE adjusted for fat-free mass was lower in malabsorptive than in non-malabsorptive patients and slightly higher than in controls, although the differences were not statistically significant. CONCLUSIONS: The results suggest that malabsorption is a frequent feature in HIV infection and is related to the HIV-related weight loss. Hypermetabolism is not a constant phenomenon in HIV infection since, in the presence of malabsorption, our patients show an appropriate metabolic response with a compensatory decrease in REE.

Adult↗

Evidence against alterations in Lecithin:cholesterol acyltransferase (LCAT) activity in familial combined hyperlipidemia.

Elevated concentrations of plasma cholesterol and triglycerides are characteristic of familial combined hyperlipidemia (FCHL) which may also present with reduced high density lipoprotein (HDL) cholesterol concentrations. Lecithin:cholesterol acyltransferase (LCAT) plays a key role in reverse cholesterol transport by converting unesterified cholesterol to cholesterol ester in the process of maturation of HDL in the presence of its activator, apolipoprotein (apo) A-I. We hypothesised that alterations in LCAT activity or plasma concentrations or gene sequence of apo A-I could influence HDL metabolism in these patients. We studied cholesterol concentrations of high density lipoprotein subfractions and LCAT activity in 25 FCHL subjects and 48 controls. Total HDL (p=0.018) and HDL2 (p=0.008) were significantly decreased in the FCHL group compared with controls. After analyses with adjusted data only HDL2 remained significantly decreased in the FCHL group (p=0.050). The LDLc/HDLc and A-I/HDLc ratios were significantly elevated in the FCHL group (p <0.0001), the latter suggesting the existence of compositional differences in the HDL particles of the FCHL individuals. LCAT activity assessed in the FCHL (19.94+/-3.95 nmol/ml per h) and control (20.13+/-6.86 nmol/ml per h) groups showed no statistically significant differences. A significant positive correlation of LCAT activity with total HDL (r=0.42), HDL3 cholesterol (r=0.46) and apolipoprotein A-I (r=0.47) was observed in affected subjects but not in controls. An association between a Ga(-75)-A variation in the promoter region of the apo A-I gene and elevated concentrations of apo A-I (p=0.009) and apo C-III (p=0.041) was observed. This association was strongly influenced by the status of the subject providing further evidence for a regulatory role of this genetic region in the expression of FCHL. Our data suggests that LCAT activity is normal in FCHL and, therefore, does not account for the abnormalities observed in these patients essentially with regard to the HDL2 subfraction.

Adult↗

Lipoprotein(a) and the significance of the association between platelet glycoprotein IIIa polymorphisms and the risk of premature myocardial infarction.

Platelet glycoprotein IIb/IIIa may be involved in the pathogenesis of myocardial infarction as the key element in platelet aggregation and as the binding site of lipoprotein(a) to platelets, inhibiting plasminogen binding and activation. Recently, a strong association between the P1A2 polymorphism of the glycoprotein IIIa gene and acute coronary thrombosis has been reported. although this has not been confirmed. In an associated study, we determined plasma lipoprotein levels, the apo E genotype and the P1A genotype in 250 males under 55 years with myocardial infarction and they were compared with 250 age- and sex-matched controls. Patients showed an over-representation of the epsilon3/4 genotype with respect to the control group. We found that there were no differences in the allelic frequency of P1A2 between case patients and age-matched controls (chi2 = 0.05, P = 0.92) and that subjects bearing the P1A2 allele showed higher plasma lipoprotein(a) concentration than p1A1/P1A1 individuals. Therefore, in this population there is no association between carriage of p1A2 allele and increased risk of myocardial infarction but the carriage of P1A2 is associated with higher plasma Lp(a) concentration.

Adult↗

[Familial combined hyperlipidemia: detection and characterisation of the hyperlipidemic profile among children and adolescents].

BACKGROUND: Familial combined hyperlipidemia is the commonest genetic form of hyperlipidemia among survivors of myocardial infarction and, therefore, its early detection is crucial for the prevention of coronary artery disease. The aim of the study was to establish the prevalence of hyperlipidemia in the offspring of affected families and to characterize their lipid, lipoprotein and apolipoprotein profile. PATIENT AND METHODS: Forty five subjects below the age of 19 were studied from which 30 were from affected families and 15 from healthy control families. Cholesterol and triglycerides in plasma, VLDL, IDL, LDL and HDL as well as apolipoproteins AI, B, C-II and C-III were measured. RESULTS: Hyperlipidemia was detected in 13 children (43%) from affected families. They also presented significantly elevated concentrations of cholesterol in plasma (p < 0.0001), LDL (p < 0.0001) and HDL (p < 0.05); triglycerides in plasma (p < 0.007), VLDL (p < 0.05) and LDL (p < 0.008), together with significantly increased concentrations of apolipoproteins AI (p < 0.02), B (p < 0.0004), C-II (p < 0.0005) and C-III (p < 0.03). No changes were observed in the IDL fraction. CONCLUSIONS: There is an elevated prevalence of hyperlipidemia among the offspring of patients with familial combined hyperlipidemia. On the contrary to that observed in adults, no alterations of the IDL fraction are present among affected children.

Adolescent↗

Oleic acid rich diet protects against the oxidative modification of high density lipoprotein.

Oxidative modifications of lipoproteins could contribute to the development of atherosclerosis, but the influence of dietary fats on high density lipoprotein (HDL) oxidative modification is unknown. This study was designed to determine whether a diet rich in oleic acid could modulate the oxidative modification of HDL3. Twenty two healthy men were randomly placed on a 32-wk crossover study of an oleic acid rich diet supplied by a variant of sunflower oil vs a linoleic acid rich diet provided by conventional sunflower oil. Plasma HDL3 obtained after the diet rich in oleic acid showed a significantly higher oleic acid content in the phospholipid than lipoprotein isolated after the linoleic acid rich diet. HDL3 isolated after the oleic acid rich diet had lower values of thiobarbituric acid reactive substances (TBARS) than HDL3 obtained after the linoleic acid rich diet both for native (mean +/- SE; 0.24 +/- 0.02 vs 0.42 +/- 0.08 nmol MDA/mg protein; p < 0.01) and copper oxidized HDL3 (0.75 +/- 0.06 vs 0.95 +/- 0.07 nmol MDA/mg protein; p < 0.01). Indeed, TBARS for native HDL3 were negatively correlated with the oleic acid to linoleic acid ratio and positively with the percentage of linoleic acid in their phospholipids. Interestingly, HDL3 after both diets had similar antioxidant vitamins A and E content. HDL3 overall composition and fluidity were similar after the two diets. Moreover, HDL3 obtained after both diets produced identical [3H] free cholesterol efflux from human monocyte-derived macrophages (29%) and fibroblasts (26%). In conclusion, HDL3 rich in oleic acid was less easily oxidized regardless of the content of antioxidants such as vitamins A and E. Therefore, dietary monounsaturated fatty acid prevent the oxidative modification of lipoproteins.

Cholesterol↗

Oxidized lipoproteins including HDL and their lipid peroxidation products inhibit TNF-alpha secretion by THP-1 human macrophages.

It has been established that oxidized LDL (ox-LDL) modifies cytokine secretion by macrophages, for example, by reducing tumor necrosis factor alpha (TNF-(alpha) m-RNA. However, little is known about the effects of oxidized high density lipoprotein (ox-HDL). This study reports the effects of ox-HDL subfractions 2 and 3 (ox-HDL2, ox-HDL3) compared with that of ox-LDL and some products of oxidation (hydroperoxides and aldehydes) on the secretion of TNF-alpha from THP-1 human monocytes derived macrophages in vitro. HDL2, HDL3 and LDL were oxidized with 10 microM Cu++ for 12 h and/or 24 h. Native and oxidized HDL and LDL were incubated for 24 h with macrophages with or without LPS (10 ng/ml) after which TNF-alpha secretion was measured in the culture medium. Lipid hydroperoxides and apolar aldehydes were also incubated with the cells for 2 h following which the medium was replaced and TNF-alpha secretion measured after a further 22 h of incubation. An inhibition of TNF-alpha by ox-HDL2 (p < .05), ox-HDL3 (p < .05) and ox-LDL (p < .05) from THP-1 macrophages was observed in the presence and absence of LPS. This inhibition remained the same after incubation with ox-HDL 12 h and 24 h. Hydroperoxides of linoleic acid did not modify TNF-alpha secretion by cells while five out of eight aldehydes analyzed (2,4-heptadienal, hexanal, 2-nonenal, 2-octenal, 2,4-decadienal) inhibited TNF-alpha secretion (p < .05). These findings demonstrate that ox-HDL, and some of its lipid peroxidation products, plays a role in the modulation of the inflammatory response by macrophages as previously observed for ox-LDL.

Aldehydes↗

Physicochemical changes in HDL3 after bezafibrate treatment: influence on free cholesterol efflux from human fibroblasts.

The effects of bezafibrate, a well-used fibric acid hypolipidemic agent, were investigated in 10 moderately hypertriglyceridemic patients. The aim was to quantify the physico-chemical modifications to high-density lipoprotein subfraction 3 (HDL3) induced by treatment and to assess, in vitro, the alterations in its principal physiological function, the efflux of intracellular free cholesterol. Treatment (200 mg/thrice/d for 3 months) resulted in a 48% decrease in plasma triglycerides, with an increase in the HDL cholesterol, due mainly to an increase in the HDL3 (P < 0.01). Composition analysis of HDL3 indicated an increase in cholesterol esters (P < 0.01), free cholesterol (P < 0.01), and phospholipids (P < 0.01), coupled with a decrease in the protein content of the molecule compared with pretreatment values. Fluorescence anisotropy at 24 degrees C was significantly higher post-treatment than pretreatment (P < 0.01). The cholesterol effluxing capacity of pretreatment HDL3 was 28%, and post-treatment this increased to 50% (P < 0.01). Multivariate analyses indicated that the increased capacity of HDL3 to promote free cholesterol efflux was, in part, due to increased HDL3 phospholipid content and a more adequate fluidity of the molecule. These findings suggest that bezafibrate induces a lowering of plasma triglycerides and that the resultant physico-chemical alterations of the HDL3 molecule make it more efficient as an acceptor of intracellular free cholesterol.

Adult↗

A variation in the apolipoprotein C-III gene is associated with an increased number of circulating VLDL and IDL particles in familial combined hyperlipidemia.

Detailed plasma lipoprotein analyses were conducted on 16 familial combined hyperlipidemic (FCHL) probands, all their available family members (n = 106) together with 12 normolipidemic control families (n = 68), and the results were assessed in relation to a C1100-T polymorphism in exon 3 of the apoC-III gene. The frequency of the T1100 genotype (CT+TT) was significantly elevated in the probands relative to control subjects (0.64 vs. 0.36; P < 0.01) and was associated with elevated concentrations of plasma triglyceride (P < 0.02) and apoC-III (P < 0.03), VLDL cholesterol (P < 0.005), VLDL triglyceride (P < 0.009), IDL cholesterol (P < 0.01). and IDL triglyceride (P < 0.007). The T1100 genotype was also associated with elevations in VLDL-apoB (P < 0.005) and IDL-apoB (P < 0.04) indicating a relationship between this variation and an increased number of triglyceride-rich particles. These findings were confined to the hyperlipidemic members of the FCHL families and showed a strong genotype-status interaction (P < 0.001). It is considerable clinical relevance that the apoC-III gene may be acting as a modifier gene that is only expressed in the presence of other factors (e.g., increased VLDL flux, low LPL activity) and therefore may predispose those members of FCHL families carrying the T1100 allele to express the FCHL phenotype.

Adolescent↗

Low plasma vitamin A concentrations in familial combined hyperlipidemia.

As many as 20% of the survivors of acute myocardial infarction present with the heritable form of hyperlipidemia, termed familial combined hyperlipidemia (FCHL). Some of the genes reported to be involved in this disorder, such as those for lipoprotein lipase (LPL) and apolipoprotein (apo) C-III, are controlled by a peroxisome proliferator-activated receptor (PPAR)/retinoic acid receptor X (RXR) regulatory system, which is retinoic acid dependent. If, as we hypothesized, the availability of retinoic acid or its precursor retinol (vitamin A) could be altered in FCHL, this could help explain some aspects of the phenotypic expression of the disease. We therefore measured plasma retinol concentrations in 30 FCHL subjects and 56 controls. Plasma retinol concentrations in FCHL subjects were significantly lower than that of control subjects (1.96 +/- 0.83 mumol/L vs 2.91 +/- 1.23 mumol/L, respectively; P < 0.0001). This novel finding of significantly decreased concentrations of plasma retinol in FCHL relative to control subjects gives support to the hypothesis that vitamin A might be involved in the expression of this disorder.

Adult↗

Blood pressure in young adults with and without a paternal history of premature coronary heart disease in Europe: the EARS Study. European Arteriosclerosis Study.

OBJECTIVE: The European Arteriosclerosis Study (EARS) was designed to identify variables which discriminate subjects with a paternal history of premature coronary heart disease (CHD) from controls and to study the distribution of these variables across Europe. In this article we report on the blood pressure (BP) data. DESIGN: Comparison of young individuals (18 to 26 years) from 14 different European universities with and without paternal history of premature (before 55) myocardial infarction (MI). SUBJECTS AND METHODS: 1994 university students were recruited, 682 with a positive paternal history of premature MI (cases) and 1312 age and sex-matched controls. Following a rigid fieldwork and analyses protocol, data on life style, BP, anthropometric and analytical measurements were obtained. RESULTS: Only diastolic BP in female patients was different between cases and controls (P < 0.05). A significantly higher prevalence of high BP personal history in male cases than in controls was observed (P < 0.02). BP means showed significant regional differences with higher values in the northern and middle European countries respect to southern regions (P < 0.0001). BP values were positively correlated to body mass index (BMI) and waist to hip (W/H) ratio, no correlations were observed with alcohol consumption in this age group. Tobacco showed a negative independent correlation with both systolic and diastolic BP (P < 0.0001). The use of contraceptive pills was associated with higher systolic (P < 0.0001) and diastolic (P < 0.05) BP levels. After adjustment for covariants, only weak correlations were observed between BP, lipids and apolipoproteins. Apo E showed a positive correlation with BP. Lp(a) and fibrinogen showed no significant regression coefficients with BP. Among cholesterylesters, oleic acid percentages were negatively correlated to BP values (mainly diastolic BP: P < 0.001), while the correlation with linoleic acid was positive (P < 0.001). Fasting glucose levels showed an independent correlation with systolic BP (P < 0.0001) in a multiple regression analysis. CONCLUSIONS: In the group with paternal history of premature MI, the higher prevalence of personal history of high BP in males and the higher diastolic BP values in females suggest that high BP could play a role in the elevated CHD risk of this group. Epidemiological observations on BP distribution and its relation with anthropometric and biochemical covariants in a young group of age from different European countries are reported.

Adolescent↗