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Biomedical subjects

M S Rosa

Publications and source records attributed to M S Rosa.

7 recordsLinked to original sources
PubMed2005

Comparison of sweat rate during graded exercise and the local rate induced by pilocarpine.

Centrally stimulated sweat rate produced by graded exercise until exhaustion was compared to the local sweat rate induced by pilocarpine, often used as a sweating index for healthy individuals. Nine young male volunteers (22 +/- 4 years) were studied in temperate environment in two situations: at rest and during progressive exercise with 25 W increases every 2 min until exhaustion, on a cycle ergometer. In both situations, sweating was induced on the right forearm with 5 ml 0.5% pilocarpine hydrochloride applied by iontophoresis (1.5 mA, 5 min), with left forearm used as control. Local sweat rate was measured for 15 min at rest. During exercise, whole-body sweat rate was calculated from the body weight variation. Local sweat rate was measured from the time when heart rate reached 150 bpm until exhaustion and was collected using absorbent filter paper. Pharmacologically induced local sweat rate at rest (0.4 +/- 0.2 mg cm-2 min-1) and mean exercise-induced whole-body sweat rate (0.4 +/- 0.1 mg cm-2 min-1) were the same (P > 0.05) but were about five times smaller than local exercise-induced sweat rate (control = 2.1 +/- 1.4; pilocarpine = 2.7 +/- 1.2 mg cm-2 min-1), indicating different sudorific mechanisms. Both exercise-induced whole-body sweat rate (P < 0.05) and local sweat rate (P < 0.05) on control forearm correlated positively with pilocarpine-induced local sweat rate at rest. Assuming that exercise-induced sweating was a result of integrated physiological mechanisms, we suggest that local and whole-body sweat rate measured during graded exercise could be a better sweating index than pilocarpine.

Adult↗
PubMed2004

Variation in the loss of seed dormancy during after-ripening of wild and cultivated rice species.

BACKGROUND AND AIMS: The aim of this paper was to verify the variation in the loss of seed dormancy during after-ripening and the interspecific and interpopulation variability in the degree of dormancy of seven wild and two cultivated rice species comprising 21 populations and two cultivars. METHODS: Four wild rice species from South America, Oryza glumaepatula, O. latifolia, O. grandiglumis and O. alta, and two O. sativa cultivars were tested in one experiment. In a second experiment, five wild species, O. punctata, O. eichingeri, O.rufipogon, O. latifolia and O. glumaepatula, and one cultivated species (O. glaberrima) were evaluated. Initial germination tests were performed soon after the seeds were harvested and subsequently at 2-month intervals, for a total of six storage periods in the first experiment and three in the second. All tests were conducted in the dark at a temperature of 27 degrees C. KEY RESULTS: Different patterns of after-ripening among populations within and between species were observed. CONCLUSIONS: The cultivated species (O. sativa and O. glaberrima) and, amongst the wild species, the tetraploids O. latifolia, O. grandiglumis and the diploids O. eichingeri and O. punctata, had weak dormancy, losing it completely 2 months after harvest, while O. rufipogon and O. glumaepatula exhibited pronounced dormancy. The latter showed different patterns of after-ripening between populations indigenous to the Amazon region and those originating in the Paraguay River system. Seeds of Solimoes (Amazon) and Japura origin showed weak dormancy whereas those of Paraguay origin showed deep dormancy. Ecological differences among natural habitats may be involved in such differentiation.

Agriculture↗
PubMed2001

Platelet-activating factor (PAF) modulates peritoneal mouse macrophage infection by Leishmania amazonensis.

The effects of platelet-activating factor (PAF) on the infection of peritoneal mouse macrophages by Leishmania amazonensis were investigated. Prior to the infection, the parasites and/or the macrophages were treated with PAF and/or one of the following modulators: WEB 2086 (PAF antagonist), and the modulators of protein kinase C, phorbol-12-myristate-13-acetate (PMA), and sphingosine. The infection was inhibited when the macrophages or both the parasites and the macrophages were treated with PAF, but stimulated by PAF-treated parasites. WEB 2086 abrogated PAF effects in both systems. The infection was stimulated when the macrophages were treated with sphingosine plus PAF, but inhibited when the macrophages were treated with sphingosine and the parasites with sphingosine plus PAF. The infection was inhibited by sphingosine-treated parasites, either in the presence or in the absence of PAF. Leishmania amazonensis-macrophage infection was inhibited by PMA in all systems tested.

Animals↗
PubMed1999

Elevated basal insulin secretion and normal dynamic insulin sensitivity in borderline hypertension.

BACKGROUND AND AIM: Borderline hypertension is often the initial stage of stabilized hypertension. This study aimed to provide insight on insulin behavior and its relationship with glucose metabolism by investigating insulin secretion and hepatic clearance in non-steady-state conditions in borderline hypertensive patients. METHODS AND RESULTS: We studied 15 patients (6 F, 9M, 44 +/- 2 yr, 78 +/- 2 kg, systolic pressure 155 +/- 10 mmHg, diastolic 93 +/- 5) and 15 comparable healthy controls. All underwent an intravenous glucose test, with minimal model analysis to measure insulin sensitivity S1, glucose effectiveness SG, insulin pre-hepatic release, hepatic extraction, and insulin appearance rate in the systemic circulation. Basal glucose (3.98 +/- 0.12 vs 3.94 +/- 0.11 mmol/L, hypertensive vs control subjects respectively), i.v. glucose tolerance factor KG (2.0 +/- 0.2 vs 2.2 +/- 0.1% min-1), SG (0.035 +/- 0.004 vs 0.032 +/- 0.007 min-1) and S1 [3.5 +/- 0.5 vs 3.8 +/- 0.3 10(4) min-1 (microU/mL)] were similar, both basal insulin and C-peptide exhibited a marked increase (87 +/- 8 vs 46 +/- 6 pmol/L, p = 0.0003; 637 +/- 62 vs 381 +/- 76 pmol/L, p < 0.03) demonstrating insulin resistance in basal conditions. Insulin secretion per unit volume was greater in patients, both at basal (43 +/- 5 vs 24 +/- 5 pmol/L/min, p = 0.01) and after stimulation (total hormone released = 18 +/- 2 vs 11 +/- 2 nmol/L in 4 h, p = 0.022). Post-hepatic insulin delivery was also elevated (basal = 11 +/- 1 vs 6 +/- 1 pmol/L/min, p < 0.002, total = 5 +/- 1 vs 3 +/- 0.3 nmol/L in 4 h, p = 0.02), while no difference was detected in hepatic extraction (66 +/- 4% vs 66 +/- 3). CONCLUSION: Borderline hypertensive patients display normal glucose tolerance with basal insulin resistance and normal dynamic insulin sensitivity. Peripheral hyperinsulinemia derives from the combination of normal hepatic extraction with an overproduction of hormone, mostly due to the basal component. Because borderline hypertension often degenerates into overt disease, our results point to a progression that leads to the well-known insulin resistance proper to sustained hypertension.

Adult↗
PubMed1994

Beta-cell response and insulin hepatic extraction in noncirrhotic alcoholic patients soon after withdrawal.

A decreased tolerance to carbohydrates has been reported in several studies of liver diseases, whereas only a few investigations have been performed in chronic noncirrhotic alcoholic patients with and without alcohol abstinence. The aim of this study was to evaluate in detail the metabolic portrait of six noncirrhotic alcoholics during the early phase of alcohol withdrawal by quantifying the main processes involved in glucose disappearance. Data from frequently sampled intravenous glucose tolerance tests (FSIGTs) were analyzed by means of the minimal model (MINMOD) approach, which provided measurements of the (prehepatic) beta-cell secretion and of insulin degradation in the liver, along with indexes of insulin sensitivity and glucose effectiveness. Plasma insulin levels were lower in the patients (basal, 3.5 +/- 0.2 v 8.0 +/- 1.8 in matching controls, P < .05; area under the curve, 1.41 +/- 0.07 mU/mL in 240 minutes v 4.06 +/- 0.37, P < .001), and C-peptide concentrations were higher (basal, 107 +/- 3.5 v 36 +/- 9 ng/dL in controls, P < .05; area under the curve, 492 +/- 118 ng/mL in 240 minutes v 245 +/- 66, P = .05). The model analysis confirmed the absence of a decrease beta-cell release; in fact, in the alcoholics there was a basal secretion of 19 +/- 5 versus 9 +/- 2 pmol/L/min in controls (P < .05) and a total release of 9.5 +/- 1.8 nmol/L in 240 minutes versus 6.5 +/- 1.4.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗