Biomedical subjects

A B Almeida

Publications and source records attributed to A B Almeida.

4 recordsLinked to original sources

PubMed2001

Gastroprotective effect of aparisthman, a diterpene isolated from Aparisthmium cordatum, on experimental gastric ulcer models in rats and mice.

Aparisthmium cordatum (Juss.) Bail. (Euphorbiaceae), known in the State of Pará, Brazil as "ariquena queimosa", is a medium-sized tree which is native to the North Brazilian coastal region. Previous phytochemical studies of the bark of A. cordatum yielded a furan diterpenoid with a clerodane skeleton, called aparisthman. Recently, we reported the antiulcerogenic activity of trans-dehydrocrotonin (DHC), a furan diterpene isolated from Croton cajucara bark, in different ulcerogenic models in mice and rats. The aim of the present study was to assess the possible antiulcerogenic activity of aparisthman. When previously administered (p.o.) at the dose of 100 mg/kg(-1), aparisthman reduced significantly (p < 0.01) gastric injury induced by the indomethacin/bethanechol (71%), ethanol (71%), pylorus ligature, (59%) and hypothermic restraint-stress models (50%), in mice and rats. In the HCl/ethanol-induced gastric ulcer model in mice, at oral doses of 100 and 250 mg/kg(-1), aparisthman from A. cordatum reduced significantly (p < 0.001) the formation of gastric lesions by 59% and 66%, respectively, as compared with control. In the pylorus-ligature model, aparisthman (p.o.) decreased the volume of gastric juice as compared with control (p < 0.001). When aparisthman (100 mg/kg(-1)) was administered intraduodenally to mice, significant modifications were found, such as a decrease in gastric acidity as compared with control. In the animals pre-treated with aparisthman, free mucus production increased by 19% in the gastric mucosa (p < 0.05). The results suggest that aparisthman from A. cordatum presents a significant anti-ulcer effect when assessed in these induced ulcer models. Although the mechanism underlying this antiulcerogenic effect remains unknown, it seems to be related to an increase of the defensive mechanisms of the stomach such as prostaglandin synthesis and mucus production. The good yield of aparisthman obtained from A. cordatum, as well as its antiulcerogenic activity, suggest that this compound should be submitted to pharmacological research as a potential new antiulcerogenic drug.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2001

Changes in the profile of lipoprotein subfractions associated with hormone replacement therapy.

OBJECTIVE: To report the effects of 2 regimens of hormone replacement therapy during the postmenopausal period on the profile of the major lipoprotein subfractions (HDL, LDL, and VLDL). METHODS: We carried out a cohort study in 38 postmenopausal patients who were starting their hormone replacement therapy due to gynecological indications, for a period of 12 weeks. Analysis of lipoprotein subclasses was performed through nuclear magnetic resonance spectroscopy. RESULTS: Hormone replacement therapy cause an increase in the proportion of larger subfractions of VLDL and HDL (p=0.008 and 0.03, respectively) and in the proportion of larger particles of VLDL due to a 36% increase in the levels of larger particles (p=0.004), concomitantly with a 15% reduction in the levels of smaller particles (p=0.04). In regard to HDL, the increase occurred only a 17% increase in the levels of larger particles (p=0.002). No significant change occurred in the distribution pattern of LDL subfractions. CONCLUSION: The proportion of larger subfractions of VLDL and HDL increases after hormone replacement therapy. The increase in the proportion of larger particles of VLDL occurs due to an increase in the levels of the larger subclasses concomitantly with a reduction in the smaller particles. However, an increase in the proportion of larger particles of HDL occurs only due to an increase in the levels of the larger subfractions.

Cohort Studies↗

PubMed1995

Hepatic enzymes' level during chronic use of anticonvulsant drugs.

We studied retrospectively 894 adult epileptic patients treated during the period from 1983 to 1992. Hepatic enzymes abnormal values were seen in 49% (n = 438). In 22.3% (n = 200), at least 2 enzyme levels in different moments were altered. They were divided in three groups: GI with alterations at transaminases (3%, n = 6), GII with alterations at GGT and AP enzymes (72%, n = 144) and GIII with alterations in both groups (25%, n = 50). No patient developed clinical symptoms of liver disease. The increase of gamma-glutamil-transferase (GGT) and alkaline phosphatase (AP) levels is frequent and not necessarily pathological. Slight increase of transaminases can occur with no clinical correlation. The routine screening of hepatic enzymes level during the chronic use of anticonvulsivant drugs in adults has a questionable value.

Adolescent↗

PubMed1992

[Not Available].

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Academies and Institutes↗