Antidiabetic activities of Tecoma stans (L.) Juss. ex Kunth.

ETHNOPHARMACOLOGICAL RELEVANCE: Tecoma stans aqueous extract (TAE) is widely used as a traditional antidiabetic remedy in Mexico; its rational use is controversial. We provide evidence of its main antidiabetic activities. AIM OF THE STUDY: To evaluate in vivo and in vitro intestinal alpha-glucosidases inhibition as the possible mode of action of TAE on type 2 diabetes mellitus (DM2) animal models, and to test the effects of its sub-chronic administration on lipids and glucose blood levels. MATERIALS AND METHODS: In healthy and streptozotocin (STZ)-induced diabetic male Sprague-Dawley rats, glucose or cornstarch was administered after an oral dose of TAE, acarbose, tolbutamide or vehicle, in order to build starch and glucose tolerance curves (STC and GTC). An intestinal brush border preparation was used to evaluate the TAE alpha-glucosidases inhibitory activity. Moreover, in STZ-induced diabetic rats TAE, tolbutamide or vehicle was administered for 21 days for evaluate their effects on fasting glucose cholesterol and triglycerides. Also, TAE total phenolic compounds were quantified. RESULTS: In STC, TAE decreased hyperglycemic peak values in both healthy and STZ-treated rats, in a magnitude similar to that of acarbose. The in vitro preparation showed a dose-dependent inhibition of glucose release from starch. Sub-chronic administration of TAE significantly reduced cholesterol and triglycerides levels. Moreover, we confirmed that acute and sub-chronic administration of TAE (500mg/kg) in both rat models did not diminish fasting glucose and did not modify the GTC. CONCLUSIONS: The study present evidence that the main antidiabetic effect of TAE is due to intestinal alpha-glucosidase inhibition by decreasing the postprandial hyper-glycaemia peak; in addition, TAE sub-chronic administration reduces triglycerides and cholesterol, without modifying fasting glucose.

[Risk stratification and prevention of sudden death in patients with heart failure]. / Estratificación del riesgo y prevención de la muerte súbita en pacientes con insuficiencia cardíaca.

Patients with heart failure can die of progressive refractory heart failure or sudden cardiac death. This article reviews the major clinical predictors of sudden death in patients with heart failure due to left ventricular systolic dysfunction. Although earlier studies have identified many independent univariate predictors of reduced survival in these patients, the positive predictive value of most of them is low. Cardioverter defibrillator implantation has been shown to be the most effective therapy in patients resuscitated after cardiac arrest caused by ventricular fibrillation or poorly tolerated ventricular tachycardia. Low left ventricular ejection fraction, low New York Heart Association functional class, unsustained ventricular tachycardia and inducibility of ventricular arrhythmia in electrophysiological studies may also identify high-risk patients who are candidates for cardioverter defibrillator implantation. The role of amiodarone in preventing sudden death in high-risk patients with heart failure seems to be small. Further studies are needed to improve risk stratification criteria to select patients with heart failure who are candidates for cardioverter defibrillator implantation.

[Learning process for transseptal puncture guided by intracardiac echocardiography]. / Resultados de la curva aprendizaje de la punción transeptal guiada mediante ecografía intracardíaca.

We prospectively analyzed the learning process for transseptal catheterization guided by intracardiac echocardiography, in 50 patients who underwent radiofrequency ablation for left atrial arrhythmias. In 20 patients the intracardiac echocardiography catheter was positioned in the right atrium to visualize the fossa ovalis and the tenting of the fossa caused by the Brockenbrough needle. In the other 30 patients, the intracardiac echocardiography catheter was positioned so that it impinged upon the fossa ovalis, and the needle was advanced alongside the intracardiac echocardiography catheter under fluoroscopic guidance in two orthogonal projections. In all but one patient, transseptal catheterization was performed successfully on the first attempt. The learning process for transseptal puncture guided by intracardiac echocardiography was uncomplicated, resulting in a procedure that is safe and effective. The intervention is simplified by positioning the echocardiography catheter at the fossa ovalis and using this as a reference point for fluoroscopic monitoring of the progress of the Brockenbrough needle.

Recent progress in biotechnology of Mexican medicinal plants.

Based on traditional medicinal knowledge, it was possible to identify the plant species Solanum chrysotrichum as the source of a new antimycotic agent designated SC-1. Cell suspension batch cultures from this plant were established in shake flasks, in which the production of SC-1 was optimized, reaching values fifty times higher than those registered in field grown plants. Large-scale cultivation of the active biomass from S. chrysotrichum was established in 10 l airlift bioreactors, and productivity levels of SC-1 were increased by 60% when using a draw-fill mode in the bioreactors.

Large-scale cultivation ofSolanum chrysotrichum cells: Production of the antifungal saponin SC-1 in 10-I airlift bioreactors.

Cells of two different cell lines:ccvx (cotyledon derived) andccvz (hypocotyl derived) ofSolanum chrysotrichum were cultivated in 10-1 airlift bioreactors for the production of the human antimycotic compound SC-1. When using 3 g l-1 dry weight inoculum in a batch culture, higher levels of biomass were achieved with theccvx cell line (14.6 g l-1) than withccvz (7.7 g l-1), resulting in 23 and 12 mg g-1 of SC-1 after 17 days in culture forccvx andccvz, respectively. The maximum productivity of SC-1 in bioreactors was 0.025 g l-1 day-1 after 9 days in culture. When using a draw-fill mode, the productivity increased by 60% to a value of 0.041 g l-1 day, 4 days after 50% of the cell suspension was removed and replaced with fresh medium. This latter bioreactor system is a feasible alternative for the production of the antimycotic metabolite ofS. chrysotrichum on a large scale.

Effects of Mimosa tenuiflora bark extracts on WI38 and KB human cells in culture.

The effects of three extracts from barks of Mimosa tenuiflora (Willd) Poir, Leguminosae, on the growth rate of two human cell lines were investigated. The plant material was extracted with petroleum ether, ethylacetate and butanol, and the obtained products were evaluated in their ability to modify growth of WI38 normal embryonic fibroblasts, and KB cells from a nasopharyngeal carcinoma in tissue culture conditions. The ethylacetate and butanol extracts produced growth rate inhibition with a different pattern depending on the cell line studied; in contrast, the petroleum ether extract markedly increased proliferation of the same cells in vitro.