Genetic variability in three populations of Hypostomus hermanni (Teleostei: Loricariidae) found in the basins of Ivaí River, Tietê River, and Sapucaí-Mirim River of Brazil.

The genetic variability in three populations of Hypostomus hermanni from the tributaries of the rivers Ivaí (Keller), Tietê (Piracicaba), and Sapucaí (Sapucaí-Mirim) was determined using electrophoresis on starch gel. The variability in the genes for eight enzymes, namely, aspartate aminotransferase (EC 2.6.1.1), glucose-6-phosphate isomerase (EC 5.3.1.9), glycerol-3-phosphate dehydrogenase (EC 1.1.1.8), isocitrate dehydrogenase (EC 1.1.1.42), -lactate dehydrogenase (EC 1.1.1.27), malate dehydrogenase (EC 1.1.1.37), malate dehydrogenase NADP+ (EC 1.1.1.40), and phosphoglucomutase (EC 5.4.2.2), was assessed. Three loci with seven alleles were obtained in the population of Keller River whereas eight loci with 20 alleles and six loci with 16 alleles were present in the populations of Piracicaba and Sapucaí-Mirim rivers, respectively. Individuals analyzed in the three watersheds presented all the detected polymorphic loci. The average heterozygosity was 0.0527, 0.1742, and 0.1299 in the Keller, Piracicaba, and Sapucaí-Mirim River populations, respectively. On the basis of identity values and genetic distances, all the three populations were determined to be genetically very similar.

Genetic variation of Prochilodus lineatus (Valenciennes, 1836) from Paraná, Baía, Miranda, and Corumbá rivers, Brazil.

The curimbatá (Prochilodus lineatus) is one of the migratory species in the Paraná River Basin impacted by the construction of dams. Mitochondrial DNA sequences and random amplified polymorphic DNA (RAPD) fragments were used to investigate genetic variability and geographic structure of five populations of curimbatá from the Paraná River Basin. A total of 1815 bp from seven polymerase chain reaction-amplified fragments representing five protein-coding mitochondrial genes were sequenced from 12 individuals. Estimates of nucleotide sequence divergence ranged from 0.00 to 0.95%. A total of 86 RAPD markers from 58 individuals were detected. Results from the Fisher exact test indicated that P. lineatus is not genetically subdivided, although significant differences in the frequencies of a few RAPD fragments were observed. This study provides useful information for stocking and management programs for resource planning of P. lineatus.

Does the metabolic syndrome predict subclinical atherosclerotic damage in an asymptomatic population at intermediate cardiovascular risk?

BACKGROUND AND AIMS: It is not clear whether the metabolic syndrome (MetS) is a distinct entity or a combination of risk factors. Several studies showed the association between MetS and cardiovascular disease (CVD). Subclinical target organ damage (TOD) is a recognized marker of atherosclerosis and predictor of cardiovascular events. Increased burden of subclinical atherosclerosis was detected in individuals with MetS. We thus aimed to examine the association between MetS and cumulative or specific TOD and to assess whether MetS predicts TOD better than the risk factors included in current definitions. METHODS AND RESULTS: We recorded TOD in 979 patients at intermediate cardiovascular risk with and without MetS according to IDF and NCEP criteria. We measured common carotid intima-media thickness, left ventricular mass index (LVMI), urine albumin to creatinine ratio (UACR), and ankle-brachial index. We found no correlation between having at least one TOD and being positive for MetS. A high UACR was associated with MetS using both IDF and NCEP criteria, while only NCEP identified individuals with increased LVMI. Using a multivariate logistic regression model including MetS, age, sex, waist circumference, triglycerides, HDL cholesterol, blood pressure and blood glucose levels we found no correlations between the presence of MetS and at least one TOD. The associations with high UACR and LVMI disappeared when age, blood pressure and glycemia were counted in. CONCLUSION: Although MetS showed some relation with subclinical renal and cardiac damage, it does not predict TOD any better than the risk factors specified in the definitions.

Differential expression for tissue-specific isozymes in three species of Hypostomus Lacépède, 1803 (Teleostei: Loricariidae).

The expression patterns of 14 enzymatic systems in skeletal muscle, liver and heart tissues of three species of Hypostomus from the Iguaçu River basin (Brazil) were investigated. Although the patterns were similar for the three species, different tissues showed differential expressions, and the data showed that differential tissue expressions of isoperoxidases may be due to preferential combination or association of polypeptide subunits. The detected patterns for SOD isozymes showed that the quaternary structures of these enzymes were in disagreement with the subunit number reported for the majority of other vertebrate groups. Tissue-specific restriction on heterotetramer formation also were described in LDH and MDHP isozymes. Thus, these tissue-specific gene expression character in the species of Hypostomus have the greatest potential to be recognized and applied in systematic studies among species of Hypostomus.

Nimesulide decreases superoxide production by inhibiting phosphodiesterase type IV.

Nimesulide, the prototype of a new class of anti-inflammatory drugs, dose-dependently decreases the production of the superoxide anion (O2-.) in N-formyl-methionyl-leucyl-phenylalanine (fMLP)- and in phorbol myristate acetate (PMA)-stimulated polymorphonuclear leukocytes. The inhibition of O2-. is possibly related to its inhibitory effect on polymorphonuclear leukocyte cytosolic phosphodiesterase type IV (IC50 = 39 +/- 2 microM), to the related increase in cAMP (P < 0.01 at 1 microM) and the subsequent increase in protein kinase A activity. In fact H-89, a specific protein kinase A inhibitor, counteracts the inhibitory effect of nimesulide on O2-. production by fMLP and PMA. The activation of protein kinase A may prompt the phosphorylation of a number of substrates, thus inhibiting the assembly of NADPH-oxidase in the plasma membrane. Accordingly, nimesulide decreases PMA-induced assembly of NADPH-oxidase in polymorphonuclear leukocytes plasma membranes by about 35%. Protein kinase A activation may also interfere with chemotaxis. Nimesulide inhibits stimulated chemotaxis and the effect is decreased by H-89. Inhibition of phosphodiesterase type IV may explain many of nimesulide's effects.

Beta-adrenergic receptors and reflex tachycardia after single and repeated felodipine administration in essential hypertension.

To verify the possible contribution of beta-adrenergic receptor down-regulation to the reversal of reflex tachycardia during chronic treatment with a dihydropyridine calcium antagonist, 11 hypertensive patients were studied with noninvasive blood pressure (BP) and heart rate (HR) monitoring after a placebo period, and on the first and seventh day of felodipine administration, 5 mg twice daily. Plasma catecholamines and neutrophil beta-adrenergic receptors were measured on the first and seventh day of treatment, immediately before and 2 h after drug administration. The first administration of felodipine was followed by a significant drop in BP (peak reduction in mean BP 24 +/- 7 mm Hg), lasting 6 h and mirrored by reflex tachycardia (peak increase in HR 14 +/- 9 beats/min). On the morning of the seventh day, 12 h after the previous felodipine administration, mean BP (MBP) was 16 mm Hg lower than on the last placebo day, while HR was unchanged. The next administration of felodipine was followed by a smaller drop in BP (MBP - 15 +/- 7 mm Hg; NS vs. placebo), while reflex tachycardia was the same as after acute felodipine (HR 13 +/- 8 beats/min; p less than 0.05 vs. placebo, NS vs. acute administration). Plasma noradrenaline concentration increased after both acute and chronic administration (p less than 0.0001), and preadministration values were highest on day 7 (p less than 0.05). Neutrophil beta-adrenergic receptor density and affinity did not change either acutely or chronically. This study gives both indirect and direct evidence that beta-adrenoceptor down-regulation does not occur during repeated felodipine administration in hypertension. Reflex tachycardia is not abolished, but is reset to lower BP levels.

[Captopril and hydrochlorothiazide combined in the treatment of mild-to-moderate hypertension. Evaluation of sugar and lipid metabolism in a long-term study]. / Captopril e idroclorotiazide associati nel trattamento della ipertensione lieve-moderata. Valutazione del metabolismo glucidico e lipidico in uno studio a lungo termine.

Ten hypertensive patients (I-IIWHO) were treated for a period of three months with captopril 50 mg + hydrochlorothiazide 25 mg once or twice daily, with the aim of evaluating the antihypertensive effectiveness of this association and the lack of influences on lipid and mainly glucose metabolism. Blood pressure and heart rate were evaluated every month, while chemical tests were performed at the beginning and at the end of the trial. Besides before and after treatment were studied blood glucose and insulin levels during oral glucose tolerance test, at times 0, 15', 30', 60', 90', 120', 180'. Our data show that captopril combined with hydrochlorothiazide has a good antihypertensive action, and doesn't alter lipid and glucose metabolism either after oral glucose tolerance test.

Acute and long-term haemodynamic effects of propranolol and indenolol in hypertension.

The haemodynamic effect of indenolol, a beta-adrenoceptor blocker with intrinsic sympathomimetic activity (ISA) in animals, has been evaluated in a double-blind cross-over randomized trial after acute (3 days) and long-term treatment (28 days), in 12 hypertensive patients in comparison with that of propranolol. Patients were evaluated at rest and during isometric exercise (hand grip). The overall acute effect of both beta-adrenoceptor blocking drugs was to decrease mean blood pressure, heart rate and cardiac output, while total peripheral resistance increased. In the long-term studies the haemodynamic effect of propranolol was still characterized by cardiodepression and unchanged peripheral resistance. Patients on the long-term treatment with indenolol showed normal cardiac output and reduced total peripheral resistance. The data are compatible with a relatively strong ISA of indenolol, which would be responsible for the haemodynamic pattern observed during chronic treatment.

Role of blood osmolality in the regulation of vasopressin secretion in man: application of a new radioimmunoassay method for vasopressin.

A radioimmunoassay for plasma arginine vasopressin (AVP) has been developed based on R2 antibody of Thomas and Lee, synthetic standard (Ferring) and extraction on Sep-Pak column. High recovery of AVP (approximately 79%) was achieved with a detection limit of 0.25 pg/ml. By improving the technique of measurement of plasma osmolality an intraassay coefficient of variation less than 1% was obtained. Physiological studies performed with this method demonstrated that AVP becomes undetectable after water loading 20 ml per Kg of water po; (N = 6) and increases in response to hypertonic saline infusion (0.05 ml/kg/min; N = 15) with a linear relationship between plasma osmolality and AVP in individual subjects; this relationship is maintained when the test is repeated in the same subjects. However when pooling all data together, the relationship between plasma osmolality and AVP is best expressed by an exponential relationship. This implies that after AVP release is initiated, the concentration of the hormone increases more rapidly than plasma osmolality and the release is continuous possibly due to recruitment of increasing number of neuronal units whose osmotic threshold varies from individual to individual.