Biomedical subjects

A D Barbosa

Publications and source records attributed to A D Barbosa.

6 recordsLinked to original sources

PubMed2001

Influence of neurosteroids on the development of rapid tolerance to ethanol in mice.

Our recent study demonstrated that neurosteroids might either facilitate or block chronic tolerance to the incoordinating effects of ethanol. The present study investigated the effects of neurosteroids on the development of rapid tolerance to ethanol-induced motor impairment using the N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine [(+)-MK-801] or the gamma-aminobutyric acid (GABA) type A (GABA(A)) receptor agonist muscimol. Male Swiss mice were pretreated with pregnenolone sulfate (0.03 to 0.15 mg/kg) or dehydroepiandrosterone sulfate (0.05 to 0.20 mg/kg) before administration of ethanol (1.9 or 2.25 g/kg) and tested with the rota-rod apparatus. Twenty-four hours later, all animals were re-tested with the rota-rod after receiving the same dose of ethanol. Pretreatment with pregnenolone sulfate or with dehydroepiandrosterone sulfate significantly facilitated the acquisition of tolerance. However, the administration of (+)-MK-801 reversed the stimulatory action of pregnenolone sulfate but did not affect the actions of dehydroepiandrosterone sulfate on ethanol tolerance. Pretreatment with pregnenolone sulfate or dehydroepiandrosterone sulfate prevented the inhibitory action of muscimol on tolerance development. Taken together, our results suggest that neurosteroids may stimulate the development of rapid tolerance to ethanol and that GABA(A) and NMDA receptor systems may be involved in these actions.

Animals↗

PubMed2000

Effect of epipregnanolone and pregnenolone sulfate on chronic tolerance to ethanol.

The aim of the present study was to investigate the influence of neurosteroids on the development of tolerance to ethanol. Male Swiss mice were injected daily with the positive allosteric modulator of the gamma amino butyric acid-A (GABA(A)) receptor epipregnanolone (5beta-pregnan-3beta-ol-20-one; 0.15 mg/kg i.p.) or pregnenolone sulfate (5-pregnen-3beta-ol-20-one sulfate sodium; 0.08 mg/kg i.p.) - considered a negative allosteric modulator of this receptor and/or positive allosteric modulator of the N-methyl-D-aspartate (NMDA) receptor - 30 min before ethanol (2.5 g/kg i.p.). They were tested on the rota-rod apparatus, under continuous acceleration (1rpm/s), at 30, 60 and 90 min after ethanol injections for 5 days. The results showed that tolerance to the motor incoordinating effect of ethanol occurred on the fifth day of treatment when this effect was blocked by pretreatment with epipregnanolone. On the other hand, ethanol tolerance was enhanced by pretreatment with pregnenolone sulfate from the second to the fifth days of treatment. Taken together, our results suggest that neurosteroids can either stimulate or block the development of chronic tolerance to ethanol. Moreover, since neurosteroids can interact with GABA(A) or NMDA receptor systems, our results suggest the involvement of these systems in the actions of neurosteroids upon ethanol tolerance.

Animals↗

PubMedDate not supplied

Cellulose acetate as solid phase in ELISA for plague.

Antigen from Yersinia pestis was adsorbed on cellulose acetate discs (0.5 cm of diameter) which were obtained from dialysis membrane by using a paper punch. ELISA for human plague diagnosis was carried out employing this matrix and was capable to detect amount of 1.3 microg of antigen, 3,200 times diluted positive serum using human anti-IgG conjugate diluted 1:4,000. No relevant antigen lixiviation from the cellulose acetate was observed even after washing the discs 15 times. The discs were impregnated by the coloured products from the ELISA development allowing its use in dot-ELISA. Furthermore, cellulose acetate showed a better performance than the conventional PVC plates.

Antigens, Bacterial↗

PubMedDate not supplied

[Effect of malnutrition and chronic use of nicotine during pregnancy on lung phospholipid concentration in neonate rats]

OBJECTIVE: The aim of the present study was to determine whether lung phospholipid concentration is affected in neonate rats "Wistar EPM-1" following a continuous 21-day gestational exposure to nicotine. METHODS: Eighty rats "Wistar EPM-1" were randomly divided in four control (diet free and water "ad libitum") groups (10 rats each): 1 - Control, 2 - Physiologic Solution (infused with 0.15ml of NaCl 0.9%), 3 - Nicotine 1 (infused with 900 micro g/kg/day of nicotine bitartrate 95%), and 4 - Nicotine 2 (infused with 2.700 micro g/kg/day of nicotine bitartrate 95%), and four undernourished (diet 13g/day and water ad libitum) groups (10 rats each), that received the same kind of treatment as the control groups. The infusion of nicotine was subcutaneous. The offspring were divided in eight groups according to their origin. RESULTS: A significant high lung phospholipid concentration was observed in the non-undernourished nicotized group which was injected with a high dose of nicotine. In the other groups, there was no alteration in that concentration. CONCLUSION: We conclude that gestational exposure to nicotine increases lung phospholipid concentration in neonate rats, and that the nutritional state also influences this lung phospholipid concentration.

Journal Article↗

PubMedDate not supplied

[Tissue weight and histologic alterations in pregnant rats submitted to malnutrition and chronic nicotine distress, and in their neonates].

The effects of a gestational exposure of 80 rats Wistar EPM-1 to nicotine and undernutrition was examined. The weight and histological alterations on the liver and lungs was evaluated on the rats and their offspring. A significantly lower weight gain, including liver and lung weight, was observed in nicotine exposed groups. There was no alteration of the placental weight. Decidual necrosis and hepatic congestion was frequent in the rats. Lung emphysema was found in the neonates.

English Abstract↗

PubMedDate not supplied

[Appendicitis in the premature newborn]

OBJECTIVE: To present a case of acute appendicitis in a premature infant. METHODS: Retrospective review of the literature using Medline and Lilacs databases, as well as the necropsy report. CLINICAL REPORT: A white male preterm infant born at 34 weeks of gestation weighing 1,750g to a primiparous mother. The Apgar score was 4 and 8 at 1st and 5th minutes, respectively. The physical exam was normal until the 9th day of life when the child developed clinical features suggestive of acute abdomen, possibly due to necrotizing enterocolitis with perforation. He was submitted to exploratory laparotomy, which leaded to the diagnostic of acute appendicitis. CONCLUSION: Acute appendicitis must be discarded on the differential diagnostic when there is a suspicion of necrotizing enterocolitis with perforation, and risk factors are not present.

Journal Article↗