Biomedical subjects

F López-Segura

Publications and source records attributed to F López-Segura.

9 recordsLinked to original sources

PubMed2000

Low-fat and high-monounsaturated fatty acid diets decrease plasma cholesterol ester transfer protein concentrations in young, healthy, normolipemic men.

BACKGROUND: Cholesterol ester transfer protein (CETP) mediates the transfer of cholesteryl esters from HDL to apolipoprotein (apo) B-containing lipoproteins. The possible atherogenic role of this protein is controversial. Diet may influence plasma CETP concentrations. OBJECTIVE: The objective was to determine whether the changes in plasma lipids observed after consumption of 2 lipid-lowering diets are associated with changes in plasma CETP concentrations. DESIGN: : We studied 41 healthy, normolipidemic men over 3 consecutive 4-wk dietary periods: a saturated fatty acid-rich diet (SFA diet: 38% fat, 20% saturated fat), a National Cholesterol Education Program Step I diet (NCEP Step I diet: 28% fat, 10% saturated fat), and a monounsaturated fatty acid-rich diet (MUFA diet: 38% fat, 22% monounsaturated fat). Cholesterol content (27.5 mg/MJ) was kept constant during the 3 periods. Plasma concentrations of total, LDL, and HDL cholesterol; triacylglycerol; apo A-I and B; and CETP were measured at the end of each dietary period. RESULTS: Compared with the SFA diet, both lipid-lowering diets significantly decreased plasma total and LDL cholesterol, apo B, and CETP. Only the NCEP Step I diet lowered plasma HDL cholesterol. Positive, significant correlations were found between plasma CETP and total (r = 0.3868, P < 0.0001) and LDL (r = 0.4454, P < 0.0001) cholesterol and also between changes in CETP concentrations and those of total (r = 0.4543, P < 0.0001) and LDL (r = 0.4554, P < 0.0001) cholesterol. CONCLUSIONS: The isoenergetic substitution of a high-saturated fatty acid diet with an NCEP Step I or a high-monounsaturated fatty acid diet decreases plasma CETP concentrations.

Adult↗

PubMed1999

[The Mediterranean diet improves the profile of male smokers compared with the diet recommended by the American Cholesterol Program (NCEP-I)].

BACKGROUND: A study of the effect of smokers' diets on their atherogenic lipidic profile. SUBJECTS AND METHODS: 41 healthy males (32 non-smokers and 9 smokers) consumed consecutively a diet low in fat and rich in carbohydrates (28% total fat content < 10% saturated fats, and 57% carbohydrates), and a diet rich in monounsaturated fatty acids (38% total fat content with 22% monounsaturated fats). At the end of each dietary period, adhesion was confirmed by quantification of LDL cholesterol esters, plasma lipids and insulin levels. RESULTS: There were no significant differences between the age or the body mass of the groups of smokers or non-smokers. After both diets tobacco was found to have a significant effect on triglyceride levels (p < 0.0007), HDLc (p < 0.007), apo A-I (p < 0.02) and the LDLc/HDLc ratio (p < 0.005), revealing an interaction between diet and both HDLc levels (p < 0.004) and LDLc/HDLc ratios (p < 0.003). With the low fat and high monounsaturated fatty acid content diets smokers presented higher triglyceride levels (both with p < 0.0002) and LDLc/HDLc ratios (p < 0.0002 and p < 0.05, respectively) and lower levels of apo A-I (p < 0.002 and p < 0.004, respectively). However, in smokers the HDLc levels were only reduced after the low fat diet (p < 0.0003) and after the diet with a high monounsaturated fat content there was a rise in HDLc levels (p < 0.02) and a drop in the LDLc/HDLc ratio (p < 0.005) compared to the group of non-smokers. There were no significant differences in the insulin levels between groups. CONCLUSION: The atherogenic lipidic profile of smokers is due to an effect of tobacco on the lipidic metabolism. This atherogenic profile is accentuated with a low fat diet rich in carbohydrates and can be rectified to some degree with a diet with a high monounsaturated fatty acid content.

Adult↗

PubMed1999

Circulating levels of endothelial function are modulated by dietary monounsaturated fat.

BACKGROUND: For the most part, the benefits of monounsaturated-rich diets (MUFA-diet) have been related to their action on plasma lipid levels. However other non-lipidic effects could also be involved in their protective effects. One of these involves the decrease in plasma levels of plasminogen activator inhibitor type 1 (PAI-1), the main inhibitor of fibrinolysis. Given that the PAI-1 is of endothelial origin, one hypothesis is that the MUFA-diet could protect against CHD by modulating some endothelial components. METHODS AND RESULTS: Healthy male subjects (n = 25) received three different consecutive diets, each lasting 28 days: a low fat NCEP-I-diet, with 28% calories as fat, 10% saturated fat (SAT), 12% monounsaturated (MUFA) and 6% polyunsaturated (PUFA); a MUFA-diet, with 38% calories as fat, 10% SAT, 22% MUFA and 6% PUFA; and a SAT rich-diet (SAT-diet), with 38% calories as fat, 20% SAT, 12% MUFA and 6% PUFA. After each dietary period, the plasma lipid profile was determined, including total cholesterol, HDL cholesterol, LDL cholesterol, total triglyceride, apo A1, apo B plasma levels and conjugated diene formation, after incubation of LDL particles with Cu 5 microM/l. Endothelial products measured in plasma were von Willebrand factor (vWF), E-selectin, Thrombomodulin and Tissue Factor Pathway Inhibitor (TFPI) levels. We observed a decrease in vWF, PAI-1 and TFPI plasma levels and an increase in lag time of conjugated diene formation after the MUFA-diet. There was a positive correlation between the decreases in TFPI and vWF and the changes in total cholesterol, LDL-C, apo B plasma levels. The decrease in TFPI was negatively correlated with the increase in lag time of conjugated diene formation. PAI-1 plasma levels were positively correlated with total cholesterol, LDL-C and triglycerides and negatively correlated with HDL-C. CONCLUSIONS: Consumption of a Mediterranean-type MUFA-diet produces a decrease in plasma levels of vWF, TFPI and PAI-1 plasma levels in young healthy males. Given that these substances are of endothelial origin, one could suggest that the MUFA of the diet has a beneficial effect on endothelial function resulting in protective changes against thrombogenesis.

Adult↗

PubMed1998

The SstI polymorphism of the apolipoprotein C-III gene determines the insulin response to an oral-glucose-tolerance test after consumption of a diet rich in saturated fats.

The S2 allele of the SstI polymorphism of the apolipoprotein (apo) C-III gene has been associated with elevated triacylglycerol concentrations, high blood pressure, and increased risk of coronary artery disease, all of which are characteristic of an insulin-resistant state. To study the effect of this mutation on carbohydrate metabolism in healthy persons, we gave 41 male subjects 3 consecutive diets. The first was rich in saturated fat [15% protein, 47% carbohydrate, 38% fat (20% saturated)], the second was a National Cholesterol Education Program Step 1 diet [15% protein, 57% carbohydrate, 28% fat (< 10% saturated)], and the last was rich in monounsaturated fat [15% protein, 47% carbohydrate, 38% fat (22% monounsaturated, < 10% saturated)]. At the end of each dietary period, subjects received an oral-glucose-tolerance test (OGTT). Apo C-III genotype significantly affected basal glucose concentrations (P < 0.045) and insulin concentrations after the OGTT (P < 0.012). APOC3*S1/APOC3*S2 subjects (n = 13) had higher insulin concentrations after the OGTT than APOC3*S1/APOC3*S1 subjects (n = 28) in the 3 periods (diet 1: P < 0.0004; diet 2: P < 0.01; diet 3: P < 0.008). Multiple regression analysis showed that this polymorphism predicted the insulin response to the OGTT (P < 0.031) and the difference between basal insulin concentrations and insulin concentrations after the OGTT (P < 0.002) with the saturated fat diet. In summary, our results suggest that the mutation in the apo C-III gene affects insulin response to an OGTT, which could result in reduced sensitivity to insulin, especially when persons consume diets rich in saturated fat.

Administration, Oral↗

PubMed1998

Effects of different dietary cholesterol concentrations on lipoprotein plasma concentrations and on cholesterol efflux from Fu5AH cells.

BACKGROUND: The fatty acid composition of the diet can modulate the effect of dietary cholesterol on plasma lipoproteins. However, HDL composition and its capacity to promote cholesterol efflux can be influenced by the diet. OBJECTIVE: Modifications in plasma lipids and in the capacity of serum to stimulate the cholesterol efflux induced by a low-fat diet [National Cholesterol Education Program (NCEP) Step I diet], by a monounsaturated fatty acid (MUFA)-rich diet, and by addition of cholesterol to both diets was studied. DESIGN: Fifteen young, healthy men followed 2 NCEP Step I diets (<30% of fat as energy, with <10% saturated fat and 14% MUFAs) for 24 d, providing 0.027 or 0.068 mg cholesterol x kJ(-1) x d(-1), and 2 oleic acid-enriched diets (38% of energy as fat, with 24% MUFAs) providing the same amount of dietary cholesterol as the NCEP Step I diets. RESULTS: Total cholesterol, LDL cholesterol, apolipoprotein (apo) B, and apo A-I concentrations decreased after the NCEP Step I and MUFA diets compared with the usual diet. HDL cholesterol also decreased after the NCEP Step I diet. Total:HDL cholesterol, apo B, and apo B:apo A-I were lower after the MUFA diets than after the NCEP Step I diets. There were no significant differences between the lipid profiles obtained after the NCEP Step I and MUFA diets were enriched with cholesterol. The capacity of serum to promote cholesterol efflux was significantly higher after the cholesterol-enriched NCEP Step I diet than after the NCEP Step I diet. CONCLUSIONS: The MUFA diet induced a better lipid profile than the NCEP Step I diet; however, the increase in the cholesterol content of both diets produced similar plasma lipid changes. The cholesterol in the NCEP Step I diet increased the cholesterol efflux induced by total serum.

Adult↗

PubMed1997

Influence of the SstI polymorphism at the apolipoprotein C-III gene locus on the plasma low-density-lipoprotein-cholesterol response to dietary monounsaturated fat.

The plasma lipid response to changes in dietary fat and cholesterol can vary between individuals. The SstI polymorphism, arising from a cytosine to guanosine substitution in the 3' untranslated region of the APOC3 gene distinguishes between two alleles--S1 and S2. The S2 allele has been associated with elevated plasma triacylglycerol, cholesterol, and apolipoprotein (apo) C-III concentrations. In 90 young men we examined the effect of the same mutation on the response of low-density-lipoprotein (LDL) cholesterol to dietary monounsaturated fat. The frequency for the S2 allele was 0.14. Subjects were fed a low-fat diet for 25 d, followed by a diet rich in monounsaturated fatty acid (22% MUFA, 38% total fat) for 28 d; lipoproteins were measured at the end of each diet. There were no significant differences in initial total cholesterol between subjects with the APOC3*S1/APOC3*S1 (S1/S1) and APOC3*S1/APOC3*S2 (S1/S2) genotypes. After consumption of the diet high in MUFA, significant increases in LDL cholesterol (0.13 mmol/L, P < 0.027) were noted in the S1/S1 subjects whereas a significant decrease was observed in the S1/S2 subjects (-0.18 mmol/L, P < 0.046). Significant genotypic effects were seen for diet-induced changes in LDL cholesterol (P < 0.00034), total cholesterol (P < 0.009), and apo B (P < 0.0014). A study of the effect of the interaction between this mutation with that present in position -76 of the APOA1 gene promoter region (G/A) revealed that both mutations had an additive effect on changes in total cholesterol, LDL cholesterol, and apo B induced by diets. Plasma LDL-cholesterol responsiveness to the diet may be explained, at least in part, by variation at the APOC3 gene locus.

Adult↗

PubMed1991

The effect of cyclosporine on exocrine function of the rat pancreas--an in vitro study.

We have studied the effect of cyclosporine on the exocrine pancreas of rats submitted to treatment with different parenteral doses (15, 30, 50 mg/kg/day) for different time periods (7 and 30 days). Serum amylase levels, pancreas weight, and total pancreatic amylase and protein content showed a dose-dependent decrease. Basal amylase secretion from isolated lobules remained unchanged. Furthermore, the pancreatic lobules from animals under cyclosporine treatment exhibited a decreased response to bethanechol stimulation. Our data suggest that cyclosporine produces a toxic effect on exocrine pancreatic function.

Amylases↗

PubMed1991

Evidence of a direct TRH effect on the rat exocrine pancreas.

In the present study, the effect of TRH on amylase secretion was determined both in vivo, by cannulating the pancreatic duct of rats, as well as in vitro, by using isolated lobules and dissociated acini. The results show that TRH inhibited both basal and stimulated in vivo amylase secretion. Nevertheless, the in vitro experiments failed to show a TRH-related inhibitory effect when TRH was used alone, although the hormone did blunt the secretion elicited by CCK8 and bethanechol from isolated lobules and dissociated acini. Results suggest that TRH can inhibit stimulated amylase secretion in rats through a direct effect on acinar cells.

Amylases↗

PubMedDate not supplied

[Treatment compliance and follow-up of arterial hypertension in an urban environment].

We have studied ambulatory hypertensive patients by means of a survey protocol, in order to observe the possible causes of inadequate control. In 8% of patients, hygienic and dietetic measures were applied, specially low-salt diet and weight loss. This percentage is very low compared to that reported by other authors. A 67% of our patients received monotherapy, being diuretics the most frequently used drug. A 71% of patients fulfilled (correctly) the prescribed drug treatment, independently of its complexity and the arterial hypertension evolution time. The degree of good treatment fulfillment, in relation to the scarce fulfillment of hygienic and dietetic measures, make us believe that in our environment patients trust drugs effects more than that of the diet. We believe that this is due, in part, to the fact that health professionals do not insist sufficiently in its fulfillment. Patient follow-up was satisfactory in only 46% of them, which conditioned the fact that hypertension control was efficient in only 39% of total. We suggest the importance of treatment and control programs in primary assistance given the better results claimed by other authors who worked with patients following protocols. Only thus the Internal Medicine Departments could be relieved from problems derived from these patients.

Antihypertensive Agents↗