Low-density-lipoprotein peak particle size in a Mediterranean population.

BACKGROUND: The predominance of small, dense low-density lipoprotein (LDL) particles ('LDL phenotype B') has been associated with a three-fold increased risk of myocardial infarction, but the feasibility of the identification of small, dense LDL as independent predictors of coronary artery disease risk in population studies remains questioned. Design We evaluated the LDL peak particle size and its relation with other established risk factors for coronary heart disease in a group of 156 randomized subjects living on the Mediterranean island of Ustica (71 males and 85 women, range of age 20-69 years), representing approximately 30% of the total population. RESULTS: The prevalence of LDL phenotype B subjects was low (approximately 15% in both men and women) and there was a clear trend for both genders in reducing the LDL peak particle size with age. Moreover, LDL phenotype B subjects had higher BMI values, prevalence of diabetes and plasma triglyceride (TG) levels and lower plasma HDL-C concentrations in comparison with LDL phenotype A individuals; in a multivariate analysis, plasma TG levels were the only variable independently associated with LDL peak particle size. CONCLUSIONS: In this population, which appears to be somewhat protected by premature coronary artery disease, a low prevalence of the LDL pattern B was found in both men and women, and plasma TG could have a key role in regulating the LDL peak particle size. The follow up, still ongoing, will provide useful information on the predictive role of LDL peak particle size on cardiovascular risk, at least in a low-risk population.

Distribution of risk factors, plasma lipids, lipoproteins and dyslipidemias in a small Mediterranean island: the Ustica Project.

BACKGROUND AND AIM: The populations of the Mediterranean area have a low incidence of cardiovascular disease (CHD). The aims of this paper are: 1) to present demographic data of the population of Ustica, a small island in the southern part of the Tyrrhenian sea that has reduced communications with the mainland and a diet presumably rich in fish; and 2) to evaluate the distribution of risk factors, plasma lipids, lipoproteins and dyslipidemias in this population. METHODS AND RESULTS: We invited all of the free-living resident population aged more than 14 years (about 800 individuals) to participate in the study; 576 responded, for a participation rate of about 73%. The distribution of cardiovascular risk factors, plasma lipids, lipoproteins and dyslipidemias were evaluated in all of the subjects. More than 60% of the population was out of the normal weight range. Total and low-density lipoprotein cholesterol levels were respectively 207.4 +/- 46.7 and 141.7 +/- 42.4 mg/dL, and similar in males and females. Lipoprotein (a) (Lp[a]) levels presented the classical "skewed" distribution and, among the apolipoprotein(a) isoforms, there was a clear predominance of intermediate-sized kringle IV repeats. Overall, 43% of the subjects had a lipid disorder: the prevalence of hypercholesterolemia was 22.8% (3.2% with severe hypercholesterolemia terolemia > or = 300 mg/dL); low high-density lipoprotein cholesterol levels were found in 22.5%; the so-called lipid triad in 2.1%; and high Lp(a) levels in 6.2%. Large familial clusters were found for some lipid disorders. CONCLUSIONS: A large prevalence of body weight disturbances and high frequency of dyslipidemias are the main characteristics of this population. Ongoing data and future longitudinal studies will better clarify the relative influence of each parameter on CHD risk and total mortality.

ApoE polymorphism in a small Mediterranean island: relationships with plasma lipids, lipoproteins and LDL particle size.

Polymorphisms of apoE gene are able to modulate lipoprotein metabolism at different steps and to influence LDL-cholesterol (LDL-C) levels and also other lipoproteins features. Population studies documented large differences in the frequency of apoE alleles which could be even related to the prevalence of cardiovascular disease. In this study we evaluated the apoE genotypes and allele frequency in 576 subjects living in a small island in the Tyrrhenian Sea and the relative contribution of apoE polymorphism on plasma lipid and lipoprotein profile, including LDL particle size. We found a cumulative frequency of 0.073, 0.866 and 0.061 for epsilon2, epsilon3 and epsilon4 alleles respectively. Moreover epsilon3 subjects had only triglyceride levels significantly lower and LDL-C and lipoprotein (a) (Lp(a)) levels higher than epsilon2 carriers. LDL-particle size was significant smaller in epsilon2 subjects than both epsilon3 and epsilon4 carriers, but the difference disappeared when data were adjusted for triglycerides. In conclusion we have provided further evidence of a low prevalence of epsilon4 allele in a Mediterranean population which may represent a genetic protective factor of these populations. Environmental factors, such as diet, occurring in this area may have attenuated the influence of this gene on plasma lipoproteins.

[Effects of ranitidine on regenerating parietal cells. A stereologic study]. / Efectos de la ranitidina sobre células parietales en regeneración. Estudio estereológico.

In this work, we have carried out a stereological and morphological study in order to verify the effects of Ranitidine on regenerating parietal cells. We have used a control group and operated or non-operated groups treated with 2, 10 and 50 mg/kg/day Ranitidine. In operated groups an ulcer was provoked by cauterization with a metallic plate in the gastric fundus. Groups treated with high doses of Ranitidine showed an increase in the connective tissue of the gastric mucosa. The stereological study in treated groups shows a decrease in the parietal volume density, and an increase in the cellular profile. Changes detected in the parietal volume density would originate a decrease in the production of CIH.

[The effects of pirenzepine on regenerating parietal cells]. / Efectos de la pirenzepina sobre células parietales en regeneración.

In this work, we have carried out a stereological and ultrastructural study in order to verify the action of pirenzepine on regenerating parietal cells. We have used a control group and operated or nonoperated groups treated with 1, 5 and 25 mg/kg/day pirenzepine. In operated groups an ulcer was provoked by cauterization with a metallic plate in the gastric fundus. Parietal cells in operated groups showed mitochondria with altered crests, a fine granular matrix and a large number of tubulo-vesicles. The comparative stereological analysis demonstrates a generalized decrease in the mitochondria, canaliculi and lysosomal volume density, and an increase in the tubulo-vesicle volume density. Changes detected in these cellular structures would originate a decrease in the production of HCl [correction of ClH].

Clonal variation in paramecium. II. A comparison of stable and unstable clones of the same serotype.

Paramecium generally expresses only one antigen on its surface from among an array of antigens. This mutual exclusion of antigens now has been shown in certain instances to be illusory. Unstable clones which will give rise to subclones with new serotypes possess several antigens. Unstable clones, even though they manifest only one serotype, continually manufacture an antigen other than the surface antigen characteristic of the serotype.