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Biomedical subjects

L Masana

Publications and source records attributed to L Masana.

At least 73 records · Page 4Linked to original sources
PubMed1991

Effectiveness of probucol in reducing plasma low-density lipoprotein cholesterol oxidation in hypercholesterolemia.

Oxidized low-density lipoprotein (LDL) interacts with macrophages to induce intracellular cholesterol ester accumulation and foam cell formation. Probucol is a lipid-lowering drug with a well-known antioxidant action. The thiobarbituric acid (TBA)-reacting substances were measured as an index of plasma and LDL lipid peroxidation in a group of hypercholesterolemic patients compared with a normolipidemic control group. The effect of probucol treatment on plasma and LDL lipid peroxidation in the hypercholesterolemic group was also evaluated. Twenty-five patients (10 men and 15 women) with total cholesterol levels greater than 6.5 mmol/liter were given probucol for 24 weeks. Lipid and apoprotein measurements were obtained at 0, 12 and 24 weeks. TBA-reacting substances were also measured in plasma and the LDL fraction. Twenty-five normolipidemic subjects matched for sex, age and body mass index underwent complete blood analysis for purposes of comparison at week 0. Plasma, LDL and high-density lipoprotein cholesterol, and plasma apoproteins A-I and B significantly decreased after 12 and 24 weeks of probucol treatment. Hypercholesterolemic subjects (men and women) had significantly higher TBA-reacting substances in plasma and LDL than control subjects had (p less than 0.05). The amount of TBA-reacting substances in plasma and LDL showed a very significant decrease after probucol treatment (40 and 44%, respectively, after 24 weeks; p less than 0.05). This reduction was not related to age, sex or body mass index, and was greater than the decrease in lipids. These results support a potential role for probucol as a coadjuvant drug in any lipid-lowering antiatherogenic therapy.

Adult↗
PubMed1991

[Acute myocardial infarct in a young woman addicted to cocaine].

A 28-year-old female, addict to cocaine and with acute myocardial infraction is reported. The patient was obese and smoked 17 cigarette packs per year. She had been consuming about 250 mg of cocaine daily for the last months until 2 weeks before admission. Coronary angiography showed a 100% stenosis of the left anterior descending artery. Although the vasospastic effect of cocaine on the pathogenesis of coronary ischemia in addicts is well known, most patients reported in the literature show coronary artery stenosis. This may lead to hypothesize about a likely atherogenic role of cocaine.

Adult↗
PubMed1991

Low density lipoprotein receptor levels and the response to dietary and pharmacological intervention in polygenic hypercholesterolemia.

To assess its hypolipidemic predictive value, maximally induced low density lipoprotein receptor activity was measured in vitro in peripheral blood lymphocytes from 20 polygenic hypercholesterolemic patients prior to their recruitment into a rigorous dietary and pharmacological treatment program. The patients in the diet program demonstrated significant beneficial changes in plasma, LDL and HDL cholesterol concentrations. After 12 weeks, those patients who had not had reductions in LDL cholesterol to within the reference range, had cholestyramine and/or bezafibrate supplements to the diet for a further six weeks. The beneficial trends continued. The LDL receptor values correlated well with pre-treatment LDL cholesterol and plasma apoprotein B concentrations (r = -0.472, P less than 0.01 and r = -0.526, P less than 0.01, respectively) and with the percentage change induced by diet (r = 0.510, P less than 0.01 and r = 0.480, P less than 0.01, respectively) and by diet supplemented with bezafibrate and cholestyramine (r = 0.634, P less than 0.05 and r = 0.629, P less than 0.05, respectively). In polygenic hypercholesterolemic patients in whom LDL receptor activity is high, treatment with diet alone may be sufficient whereas those with low receptor activity would require specific pharmacological intervention.

Adult↗
PubMed1991

The Mediterranean-type diet: is there a need for further modification?

The effects on plasma lipoproteins of four fat-modified diets were assessed in 11 nuns in a contemplative order in the Mediterranean region of Spain. Diet 1 [high polyunsaturated fatty acid (PUFA), low monounsaturated fatty acid (MUFA), low ratio of PUFAs to saturated fatty acids (P:S)] and diet 3 (low PUFA, high MUFA, low P:S) induced significant, directly comparable reductions in total plasma (12% and 13%, respectively) and low-density-lipoprotein (LDL) cholesterol (24% and 19%, respectively). Diet 2 [high PUFA, high MUFA, low saturated fatty acid (SFA), high P:S] induced greater decrements (23% and 30% in total plasma and LDL cholesterol, respectively). Diet 4 (low PUFA, low MUFA, high SFA, low P:S) induced a significant increase in LDL cholesterol of 11%. No significant changes in high-density-lipoprotein cholesterol were observed with these diets. Because the effects of PUFAs and MUFAs are comparable, no recommendations on modifying the habitual, high-MUFA-containing Mediterranean diet need be made other than, perhaps, a reduction in the overall intake of SFAs.

Adult↗
PubMed1990

Abnormalities of lipoprotein metabolism in patients with the nephrotic syndrome.

BACKGROUND AND METHODS: Patients with the nephrotic syndrome characteristically have multiple abnormalities of lipoprotein metabolism, but the cause and exact nature of these abnormalities are uncertain. In this study, we measured serum lipids and apoproteins in 57 patients with the nephrotic syndrome. We also determined the kinetic indexes of low-density lipoprotein (LDL) metabolism in six patients, and again in three of the six after recovery. RESULTS: The patients with the nephrotic syndrome had elevated serum concentrations of cholesterol, triglycerides, and phospholipids, which were confined to the lipoproteins containing apoprotein B. The serum concentrations of high-density lipoproteins and the associated A-I and A-II apoproteins were similar in the patients with the nephrotic syndrome and normal subjects. The relative proportions of lipids and their positive association with the increased serum concentrations of apoproteins B, C-II, C-III, and E suggest quantitative rather than qualitative differences in the lipoproteins. All the patients had lipiduria, which probably reflected the excretion of high-density lipoproteins, although no intact immunoreactive apoprotein A-I was found in urine. Serum albumin concentrations were inversely related to serum lipid concentrations in the patients, the severity of the hypoalbuminemia corresponding to the degree of change in serum lipoprotein concentrations. The kinetic studies of lipoprotein metabolism revealed an overproduction of LDL apoprotein B that returned to normal after recovery. CONCLUSIONS: The elevated serum concentrations of LDL cholesterol, other lipids, and apoprotein B in patients with uncomplicated nephrotic syndrome are due to reversible increases in lipoprotein production.

Adolescent↗
PubMed1990

[Changes in lipoproteins and hormones induced by diet and drugs in patients with polygenic hypercholesterolemia. Predictive value of the determination of low density lipoprotein receptor activity].

To assess its hypolipidemic predictive value, maximally induced low density lipoprotein receptor activity was measured in vitro in peripheral blood lymphocytes from 20 polygenic hypercholesterolemic patients prior to their recruitment into a rigorous dietary and pharmacological treatment program. The subjects in the diet program demonstrated significant beneficial changes in plasma, LDL and HDL cholesterol concentrations. After 12 weeks, those patients who had not had reductions in LDL cholesterol to within the reference range had cholestyramine and/or bezafibrate supplements to the diet for a further 6 weeks. The beneficial trends continue. The initial LDL receptor values correlated well with pre-treatment LDL cholesterol and plasma cholesterol and apoprotein B concentrations, and with the percentage change induced by diet and by diet supplemented with bezafibrate and cholestyramine. During the trial the only significant variations in plasmatic hormones were observed in TSH and T3 concentrations, but always within the reference range. In polygenic hypercholesterolemic patients in whom LDL receptor activity is high, treatment with diet alone may be sufficient whereas those with low receptor activity would require specific pharmacological intervention.

Adult↗
PubMed1990

[Polymorphisms of the Apo B gene in a healthy population and its association with hyperlipidemia].

The apoprotein B gene restriction fragment length polymorphism are studied using the endonuclease XbaI, and the pAB3.5C probe was studied in 128 healthy males aged 20-62 years (39.2 +/- 7.6). The genotypic prevalence was X1X1 26.6%; X1X2 47.7% and X2X2 25.7%. The allelic frequency was 50.3% X1 and 49.7 for X2. No differences in prevalence were observed related to age or body mass index. The genotype X2X2 was statistically associated with a 10% increase in total plasma cholesterol, LDL cholesterol and LDL Apo B levels (p less than 0.05). Up to 6% of the total plasma cholesterol levels were dependent on X2X2 genotype as shown by multivariate regression analysis. The X2X2 genotype may be a candidate marker in assessing increased risk for coronary heart disease.

Adult↗
PubMed1990

Toxicity of lovastatin in rats with experimentally induced nephrotic syndrome.

The effect of lovastatin on the hyperlipidemia induced in rats with experimental nephrotic syndrome was investigated; toxicity and the effects on common blood chemistry parameters were also assessed. Hyperlipoproteinemia in this particular model is associated with an increase in hepatic synthesis of lipoproteins, and treatment with lovastatin could be the most suitable, since the drug inhibits cellular cholesterol synthesis. Lovastatin treatment resulted in a considerable reduction in plasma cholesterol and triglyceride levels. The decrease in cholesterol levels with treatment was mainly confined to the low-density lipoproteins (LDL) although there was a reduction in the nephrotic-syndrome-induced incremental level of high-density lipoprotein cholesterol. Other lipoprotein fractions were unaffected by lovastatin. LDL apoprotein B was increased in both groups of rats, but to a lesser degree in the lovastatin-treated group, suggesting a double effect, inhibition of both, cholesterol and apoprotein synthesis. Both groups of rats showed a certain degree of renal impairment as shown by significant elevations in plasma urea and creatinine levels. Hepatic damage was also observed, chemically and microscopically, in both groups of rats, being more pronounced in those rats treated with lovastatin in which a 50% mortality ensued after 2 weeks of treatment. At the dosage used this may have some implications in its therapeutic use in certain conditions.

Animals↗
PubMed1989

Treatment of diet-resistant polygenic hypercholesterolaemic patients with a new nicotinate derivative; in vivo and in vitro low density lipoprotein metabolic studies.

Six patients (four women and two men) with mild to moderate hypercholesterolemia, but with no clinical evidence of the disease being monogenic familial hypercholesterolaemia and who, over the previous 3 months on a rigidly controlled hypolipidaemic diet therapy, showed no reduction in plasma cholesterol levels, were recruited into a study to assess the metabolic effects of Pirozadil, a new nicotinic acid derivative. After a 3 month treatment period, a significant reduction in plasma cholesterol from 299.8 +/- 31.2 mg/dl (mean +/- SD) to 256.8 +/- 18.1 mg/dl (P less than 0.02) and Low Density Lipoprotein (LDL) cholesterol from 211.7 +/- 44.9 mg/dl to 168.8 +/- 19.0 mg/dl (P less than 0.05) was observed. Although there was a trend toward decreased plasma and Very Low Density Lipoprotein (VLDL) triglyceride, the differences did not reach statistical significant. High Density Lipoprotein (HDL) cholesterol was unchanged. The drug was well tolerated with no side effects noted. To assess the mode of action, autologous125I-labelled LDL was injected and apoprotein B (apo B) kinetic parameters were measured; production rate (PR) and fractional catabolic rate (FCR). An in vitro measurement of the in vivo catabolism (LDL-apo B receptor activity in freshly isolated lymphocytes) was also measured pre- and post-treatment. The pharmacological intervention resulted in a significant decrease of 19.9% in PR from 10.5 +/- 1.81 mg/kg/d to 8.41 +/- 1.13 mg/kg/d (P less than 0.05) while the FCR remained relatively unchanged (0.260 +/- 0.042 vs 0.248 +/- 0.040 pools/d) as did the LDL receptor activity (78.2 +/- 20.9 vs 69.3 +/- 21.4 ng LDL/mg cell protein/hr).(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoproteins B↗
PubMed1989

Low density lipoprotein metabolism in rats with puromycin aminonucleoside-induced nephrotic syndrome.

With puromycin aminonucleoside-induced nephrotic syndrome (NS) in rats, twofold elevated levels of lipoproteins were observed. These levels were not related to proteinuria or to plasma albumin levels. Ultrastructural lesions induced in the kidneys by puromycin aminonucleoside were consistent with NS, while there was little or no hepatic involvement. Apolipoprotein B (apo B) kinetic measurements using homologous 125I-labeled low density lipoproteins (LDL) demonstrated a higher synthetic rate in nephrotic rats relative to controls (6.18 +/- 1.86 micrograms x g-1 x d-1 v 3.94 +/- 0.66 micrograms x g-1 x d-1 respectively, P less than .005), while the fractional catabolic rate was only marginally reduced (1.64 +/- 0.28 pools x day-1 in NS v 1.83 +/- 0.37 pools x day-1 in controls, P less than 0.4). These results indicate that in rats with experimentally induced NS, the expanded apo B-LDL pool results from increased synthesis of this apoprotein while no significant role can be ascribed to alterations in its catabolism. These data are consistent with our preliminary findings in NS in humans.

Animals↗
PubMed1989

Concentrations of lipids and apolipoproteins in patients with clinically well-controlled insulin-dependent and non-insulin-dependent diabetes.

The triglyceride and cholesterol content of total, very-low-, intermediate-, low-, and high-density lipoproteins, and of apolipoproteins (apo) Al, All, B, Cll, Clll, and E were determined in plasma from 107 patients with clinically well-controlled diabetes and from 66 age- and weight-matched healthy normal subjects. The diabetic patients were separated into two groups: those with insulin-dependent diabetes mellitus (IDDM, type 1, n = 24) and those with non-insulin-dependent diabetes mellitus (NIDDM, type 2, n = 83). The latter group contained two subgroups: those treated by diet (type 2d, n = 42) or by insulin (type 2i, n = 41). High-density lipoprotein cholesterol was increased in IDDM patients, and decreased in NIDDM patients relative to control subjects. Mean apo Al values in IDDM patients were higher than in their respective controls and in NIDDM patients. Concentrations of apo B, Clll, and E were higher in all diabetic patients than in the healthy controls, but those of apo Cll did not differ statistically between diabetics and nondiabetics. Although total plasma cholesterol and triglyceride concentrations were apparently near normal values in patients with good glycemic control, we found a persistent increase of intermediate-density lipoproteins (remnants) in all the diabetic groups studied. This factor may be related to the perceived increased cardiovascular risk in these individuals.

Adult↗