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Biomedical subjects

A Castro

Publications and source records attributed to A Castro.

At least 415 records · Page 23Linked to original sources
PubMed1989

Serum IgA antibodies in HSV asymptomatic genital infections.

Cervico-vaginal swabs and serum samples from 81 women without herpes-associated clinical symptoms were examined for virus isolation and for the presence of IgA antibodies to herpes simplex virus (HSV) using the indirect fluorescent antibody technique. Nineteen of the 81 women were followed up for 2 years. Blood samples and swabs from cutaneous lesions were obtained from another group of 20 women (medical staff) with herpes labialis. By analysing the specific anti-HSV IgA antibodies, a higher geometric mean titre (GMT) was found in women with positive HSV-2 isolation (GMT = 380.03), as opposed to the GMT observed in women with negative HSV-2 (GMT = 63.43) or positive HSV-1 isolation (GMT = 55.15). Results from the longitudinal study also demonstrated that positive virus isolation always correlated with a marked rise in serum IgA antibody to HSV.

Adolescent↗
PubMed1989

Effects of age and cigarette smoking on serum concentrations of lipids and apolipoproteins in a male military population.

The effects of age and cigarette smoking on lipids and apolipoproteins were studied in men, 20-65 years old, randomly selected from a military population in the Madrid area, Spain. Subjects were classified as non-smokers, medium smokers (10-20 cigarettes/day) and heavy smokers (more than 20 cigarettes/day). Smoking prevalence was 58%. Serum apolipoprotein A-I and HDL-cholesterol (HDL-C) were not age-dependent, while total cholesterol (TC), triglycerides (TG), LDL-cholesterol (LDL-C) and the TC/HDL-C ratio increased with age. None of the variables studied was age-dependent over 30 years. The effects of smoking on TC, TG, LDL-C, HDL-C, TC/HDL-C ratio, apolipoprotein A-I, apolipoprotein B, and apo A-I/apo B ratio in the 20-29-year-old group appeared to be prominent in heavy smokers (P values less than 0.001, less than 0.05, less than 0.01, less than 0.05, less than 0.001, less than 0.05, less than 0.01 and less than 0.05, respectively) but not in medium smokers, in which only TG increased significantly (P less than 0.001). Few differences were noted between non-smokers and smokers over 30 although the TC/HDL-C ratio did increase in heavy smokers (P less than 0.05).

Adult↗
PubMed1989

The effect of acute and subchronic treatment with cicletanine on DOCA-salt hypertension in the rat.

Cicletanine, a new furopyridine derivative synthetized by the Institut Henri Beaufour (France) was found to work as an efficient antihypertensive agent in DOCA-salt rats. This compound also inhibited the development of cardiac hypertrophy characteristic of this sort of hypertension. The mechanism of antihypertensive action at nondiuretic doses of cicletanine remains to be studied.

Animals↗
PubMed1989

Normotension with decreased plasma renin activity and low serum ionic calcium levels: a prehypertensive state?

We studied the relationships between the renin-angiotensin-aldosterone system and calcium and magnesium levels in both serum and urine in 51 volunteer normotensive subjects, divided into two groups. Group 1 was made up of the 25 subjects whose levels of plasma renin activity were the lowest (1.93 +/- 0.70 ng/ml/hr). Group 2 comprised the 26 subjects with the highest plasma renin activity levels (4.80 +/- 0.84 ng/ml/hr). The following parameters were measured on all subjects: plasma renin activity and plasma and urinary aldosterone levels (by radioimmunoassay), serum ionic calcium levels (by Nova-2), total serum calcium, and serum and urinary magnesium values (by atomic absorption), serum and urinary sodium and potassium levels (by flame photometry), and creatinine clearance. In the group with low plasma renin activity (group 1), our findings included low serum ionic calcium levels (P less than .001); high coefficients of plasma aldosterone/plasma renin activity and urinary aldosterone/plasma renin activity (P less than .001); a significant correlation between the serum ionic calcium level and plasma renin activity (P less than .001); and an inverse correlation between systolic arterial tension and the serum ionic calcium level (P less than .05). These changes were more similar to change described in hypertensive patients with low plasma renin activity than to the findings in group 2 subjects. We speculate that normotensive subjects with low plasma renin activity present significant changes in the relationship between the renin-angiotensin-aldosterone system and sodium and calcium levels, and that this group is at risk for hypertension. A diet low in sodium and high in calcium could be an effective preventive measure.

Adult↗
PubMed1989

Studies on the mechanism of action of the antihypertensive agent cicletanine.

DOCA-salt rats have been previously shown to respond readily to the antihypertensive agent cicletanine (C). To study the mechanism of action of this drug, DOCA-salt rats were subchronically (14 d) treated with a 30 mg/kg (p.o.) dose of C and, once killed, their thoracic aortas challenged with a concentration (0.1 microM) of the vasocontractile agent noradrenaline (NA). Arteries from rats treated with C responded less to NA than the arteries from rats given placebo for the same time period. In another set of experiments, prior treatment with the inhibitor of prostaglandin synthesis indomethacin (2 x 2.5 mg/kg, s.c.) blunted the acute antihypertensive effect of C (30 mg/kg, p.o.) in this experimental model. These data suggest that C may work through a long-term induced blockade of the sympathetic tone that could be somehow related to a promotion of the formation of the vasodilator prostaglandin prostacyclin.

Animals↗
PubMed1988

Food intolerance in duodenal ulcer patients, non ulcer dyspeptic patients and healthy subjects. A prospective study.

In 50 duodenal ulcer out-patients and 50 non ulcer dyspeptic patients suffering from low to moderate epigastric painful symptoms the intolerance of 39 foods were significantly increased compared to a group of 50 healthy subjects. Food intolerance was not different between duodenal ulcer and non ulcer dyspeptic patients. Intolerance was related in the majority of nutrients to aversion and pain or to an increased incidence of aversion alone in patients and normals. In duodenal ulcer, coffee and fruit juice were associated with an elevated incidence of pain.

Adolescent↗
PubMed1988

Lymphocytes proliferation kinetics and SCE variation after rubella vaccination.

The effect of anti-rubella vaccination on lymphocyte proliferation kinetics in vitro and on SCE frequency was studied in three young women. The studies were carried out by taking blood samples before vaccination (day 0) and subsequently on days 7, 14, 28 and 42. The mitotic index (MI) shows a decrease at day 14 and 28 followed at day 42 by an increase above day 0 levels. The average cell cycle (ACC) shows a decrease at day 14 followed by an increase at day 28. Complex variations were also found in the percentage distribution of cells in the various division classes. The SCE frequency showed variations inverse to the MI. The whole picture seems to indicate the existence of changes in the lymphocyte population which can be correlated with immune response.

Antibodies, Viral↗
PubMed1988

High blood pressure induced by audiovisual stimulation in young rats: effect of antihypertensive agents.

High systolic blood pressure (BP) was induced in young Wistar rats by daily exposure for 30 mins to environmental stimuli consisting of intense (100 dB) sound of 7500 cps and flashing light (0.3 cps). Maximal BP enhancement was obtained after the application of both these stimuli for 3 consecutive days. Such a hypertensive response was detected 24 hrs, but not 1 hr after the trial. High BP backed to normal 72 hrs after discontinuation of the audiovisual stimulation trials. Clinically effective antihypertensive agents (clonidine, prazosin, propranolol, practolol and metoprolol) as well as a new compound under investigation (cicletanine) were proved active in this model. Normotensive nonstressed rats run in parallel did not show any variation in their BP after administration of the same dose of the drugs assayed. This experimental model of hypertension may be a useful tool not only to test new antihypertensive agents but also to study the intriguing question of the role of stress in the development and maintenance of essential hypertension.

Acoustic Stimulation↗
PubMed1988

The relationship between low plasma renin activity, low serum ionic calcium, and elevated systolic arterial tension in the normotensive elderly.

Plasma renin activity, plasma and urinary aldosterone, and serum and urinary calcium and magnesium were studied in forty elderly normotensive subjects and 37 normotensive young adult controls. Arterial tension was also recorded for each subject. The most important findings were significantly lower levels (P less than 0.001) of plasma renin activity, urinary aldosterone, and serum ionic calcium in the elderly group. A significant positive correlation was shown between calcium and plasma renin activity (P less than 0.001); an inverse correlation was found between systolic arterial tension and calcium (P less than 0.001). These findings indicate age-related physiological changes between the renin-aldosterone system, calcium, and systolic arterial tension. These changes are similar to those found previously in young adult hypertensives with low plasma renin activity levels, suggesting that the arterial tension of the elderly is labile, and that changes in the renin-angiotensin-aldosterone system (RAA) and calcium levels directly influence the increase of systolic arterial tension, which is frequently found in the elderly.

Adult↗
PubMed1988

Changes in calcium and magnesium metabolism in essential arterial hypertension.

We studied 60 hypertensive patients (35 men and 25 women with an average age of 40 years) for signs of metabolic changes, with special emphasis on the relationship between the calcium and magnesium levels. The control group comprised 37 normotensive subjects (19 men and 18 women with an average age of 39 years). We studied the total serum calcium level (measured by atomic absorption), the ionized serum calcium level (by Nova 2 testing), and the plasma protein level, and we did coefficiency studies of the creatinine clearance and calcium and magnesium levels in 24-hour urine collections. In the hypertensive group, the ionized calcium level was significantly lower than that of the control subjects (P less than .001); the total serum calcium level was also lower, but the difference was of less statistical significance (P less than .05). There was no difference in serum magnesium levels between the two groups. There was a highly significant correlation between the total serum calcium level and the serum magnesium level (P less than .001) in the normal subjects; this correlation was not found in the hypertensive group. An increase in calcium and magnesium excretion was found in the 24-hour urine collections of the hypertensive group (P less than .001) (coefficient expressed as fractionated excretion of calcium and magnesium). There was also a high correlation between urinary excretion of calcium and magnesium (P less than .001) in the hypertensive subjects. Thus, the hypertensive subjects had changes in calcium metabolism that were related to magnesium levels. We suggest, therefore, that these two factors be studied simultaneously in evaluating patients with essential arterial hypertension.

Adult↗
PubMed1988

Aldosterone and magnesium in essential arterial hypertension.

Thirty mildly hypertensive patients and 27 patients with severe essential hypertension and high levels of aldosterone were selected for a study of the relationship between plasma aldosterone and magnesium in essential arterial hypertension; levels of calcium and potassium were also studied. Thirty-six individuals were used as a control group. Our findings indicate that as plasma aldosterone levels increase, serum magnesium levels decrease correspondingly: in mild hypertensives with low levels of plasma aldosterone p less than 0.05 and in the most severely hypertensive patients with high levels of plasma aldosterone p less than 0.001. In this latter group we also found an inverse correlation between serum magnesium and systolic arterial pressure (p less than 0.001) and diastolic pressure (p less than 0.01). In these patients a significant increase in urinary excretion of magnesium was found, with levels 3 times higher than in the control group. These findings suggest a close relationship between changes in plasma aldosterone and magnesium. Possibly the aldosterone contributes through this mechanism to maintaining the hypertensive state in essential arterial hypertension. This action is exercised directly through the kidney, leading to a small but constant urinary loss of magnesium. This in turn leads to a chronic depletion of magnesium in hypertensives who have high levels of plasma renin activity and highly elevated plasma aldosterone.

Adult↗
PubMed1988

Antihypertensive effect of non-diuretic doses of cicletanine on a stress-induced model in the rat.

Cicletanine was tested at different doses (7.5, 10 and 30 mg/kg, p.o.) on young rats showing high blood pressure readings after social deprivation for 7 consecutive days. At all dose levels, the compound produced a statistically significant decrease in systolic blood pressure of isolated but not group-housed rats. In contrast, the drug did not affect the heart rate in any of the cases. Interestingly, cicletanine was only found to enhance urinary excretion at the highest dose assayed. The putative mechanism of the antihypertensive action of the drug at non-diuretic doses is discussed.

Animals↗
PubMed1987

Effect of hypoglycin A on insulin release.

Thirty experimental and fifteen control Wistar rats were studied to determine whether hypoglycin A influences insulin levels in the body to contribute to the state of hypoglycemia usually observed in Jamaican vomiting sickness, a condition arising after ingestion of unripe ackees. This fruit also grows in other Caribbean islands, as well as North and Central America. Hypoglycin A is one of the toxic compounds found in unripe ackees and is capable of inducing hypoglycemia. A fall in blood glucose occurred after administration of hypoglycin A. The lowest level of 42.60 +/- 4.84 mg/dl was attained 3 hr after administration of the drug. This alteration of blood glucose from the fasting level of 80.31 +/- 5.20 mg/dl was significant (P less than 0.01). The blood glucose level in the control rats showed no significant change from the fasting level. The insulin level in portal and peripheral blood showed no significant change. Results showed that, although hypoglycin A induced severe hypoglycemia after intravenous application, there was no significant change in insulin levels. This observation suggests that hypoglycin A has a mechanism of action other than an alteration in insulin levels to induce hypoglycemia.

Animals↗