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INTRODUCTION:Gynura procumbens has been shown to decrease blood pressure via inhibition of the angiotensin‐converting enzyme. However, other mechanisms that may contribute to the hypotensive effect have not been studied.OBJECTIVES:To investigate the cardiovascular effects of a butanolic fraction of Gynura procumbens in rats.METHODS:Anaesthetized rats were given intravenous bolus injections of butanolic fraction at doses of 2.5–20 mg/kg in vivo. The effect of butanolic fraction on vascular reactivity was recorded in isolated rat aortic rings in vitro.RESULTS:Intravenous administrations of butanolic fraction elicited significant (p<0.001) and dose‐dependent decreases in the mean arterial pressure. However, a significant (p<0.05) decrease in the heart rate was observed only at the higher doses (10 and 20 mg/kg). In isolated preparations of rat aortic rings, phenylephrine (1×10‐6 M)‐ or potassium chloride (8×10‐2 M)‐precontracted endothelium‐intact and ‐denuded tissue; butanolic fraction (1×10‐6–1×10‐1 g/ml) induced similar concentration‐dependent relaxation of the vessels. In the presence of 2.5×10‐3 and 5.0×10‐3 g/ml butanolic fraction, the contractions induced by phenylephrine (1×10‐9–3×10‐5 M) and potassium chloride (1×10‐2–8×10‐2 M) were significantly antagonized. The calcium‐induced vasocontractions (1×10‐4–1×10‐2 M) were antagonized by butanolic fraction concentration‐dependently in calcium‐free and high potassium (6×10‐2 M) medium, as well as in calcium‐ and potassium‐free medium containing 1×10‐6 M phenylephrine. However, the contractions induced by noradrenaline (1×10‐6 M) and caffeine (4.5×10‐2 M) were not affected by butanolic fraction.CONCLUSION:Butanolic fraction contains putative hypotensive compounds that appear to inhibit calcium influx via receptor‐operated and/or voltage‐dependent calcium channels to cause vasodilation and a consequent fall in blood pressure.

A new method was established for the simultaneous determination of Sn(II) and Sn(IV) using differential pulse polarography (DPP). Among several electrolytes, 0.1 M NaOH in the presence of 0.1 M KNO 3 was found to be the most suitable one. In this medium, Sn(II) had 2 peaks, at -0.74 and -1.17 V, which were sharp and very sensitive. Sn(IV), on the other hand, had a very small peak at -0.92 V when its concentration was higher than 4.0 × 10 −4 M. Thus, it was decided to determine Sn(IV) after reduction into Sn(II). In the presence of both Sn(II) and Sn(IV), Sn(II) was first determined from the peak at -1.17 V, and then Sn(IV) was determined after its reduction with NaBH 4 into Sn(II). The detection limit was 5.5 × 10 −7 M and 8.2 × 10 −7 M for Sn(II) and Sn(IV), respectively. The interference effect of the most common ions, Fe(III), Cu(II), Pb(II), Cd(II), and Zn(II), was investigated. Only copper and iron had an interfering effect during the speciation procedures, since they oxidized Sn(II), which was formed after reduction of Sn(IV) for its determination. This effect of Cu(II) and Fe(III) ions could be eliminated by the reducing agent NaBH 4 , which was used for the reduction of Sn(IV). Since Pb(II) and Cd(II) peaks overlap with the first peak of Sn(II) at -0.74V, Sn(II) was determined using the second peak, at -1.17 V. In a synthetic sample containing Sn(II), Sn(IV), and all common ions, the total content of tin (2.0 × 10 −5 M) was found to be (2.07 ± 0.38) × 10 −5 M (90% CI, N = 3). This method was applied for the determination of tin in canned tomato sauce.

Skin grafts are indicated when there is a major loss of skin. Full-thickness skin graft is an ideal choice to reconstruct defect of irregular surface that is difficult to immobilize. Full-thickness mesh grafts can be applied to patch large skin defect when there is less donor site in extensively traumatized and burned surgical patients. The concept of using natural biomaterials such as keratin, basic fibroblast growth factor is slowly gaining popularity in the field of medical research to achieve early healing. The main objective of this study is to evaluate the efficacy of gelatin conjoined with keratin processed from the poultry feather and commercially available basic fibroblast growth factor (bFGF) as a sandwich layer in promoting the viability of full-thickness skin mesh grafts. The efficacy was assessed from the observation of clinical, bacteriological, and histopathological findings in three groups of experimental dogs. The clinical observations such as color, appearance and discharge, and hair growth were selected as criteria which indicated good and early acceptance of graft in keratin-gelatin (group II). On bacteriological examination, Staphylococcus aureus and Proteus was identified in few animals. Histopathological study of the patched graft revealed early presences of hair follicles; sebaceous gland, and normal thickness of the epidermis in keratin-gelatin in group II treated animals compared with other group (group I-control, group III-bFGF-gelatin).