Antioxidant Properties and Protective Effects of Some Species of the Annonaceae, Lamiaceae, and Geraniaceae Families against Neuronal Damage Induced by Excitotoxicity and Cerebral Ischemia.

This study aimed to compare the antioxidant activities of extracts obtained from three plant families and evaluate their therapeutic effect on strokes. Ethanol extracts were obtained from either the leaf or the aerial parts of plants of the families Annonaceae (Annona cherimola, A. diversifolia, A. muricata, A. purpurea, and A. reticulata), Lamiaceae (Salvia amaríssima and S. polystachya), and Geraniaceae (Geranium niveum and G. mexicanum). Extracts were analyzed in terms of hydroxyl radical (OH•), peroxyl radical (ROO•), and superoxide anion (O2•-). The efficiency of the extracts to prevent neuronal death induced by excitotoxicity was tested with the tetrazolium assay, the O2•- scavenging capacity was evaluated with the dihydroethidium dye, and the protective effect of the extracts with the highest antioxidant activity was tested on a stroke experimental model. The extracts' IC50 values (µg/mL) of scavenging varied from 98.9 to 155.04, 4.5 to 102.4, and 20.2 to 118.97 for OH•, ROO•, and O2•-, respectively. In the excitotoxicity model, Annonaceae extracts were highly cytotoxic while Lamiaceae and Geraniaceae reduced intracellular O2•- production and protect neurons against oxidative stress. Salvia polystachya reduced cerebral damage, as well as improved survival and behavior after ischemia. Our results encouraged the use of plant extracts as natural antioxidants to minimize neuronal injury following stroke.

Gestational undernourishment modifies the composition of skeletal muscle transverse tubule membranes and the mechanical properties of muscles in newborn rats.

BACKGROUND/AIMS: [corrected] Skeletal muscle (SM) constitutes more than 40% of the body weight in adulthood. Transports dietary glucose mainly through the insulin-dependent glucose transporter (Glut-4) located in the Transverse tubule membrane system (TT). The TT development ends shortly after birth. The TT membrane hosts the proteins involved in excitation-contraction coupling and glucose uptake. Glycaemic regulation through movement is a key function of fully developed skeletal muscle. In this study, we aimed to characterize the effect of gestational undernourishment (GUN) in rats GLUT-4 expression and on the protein/lipid content of the TT membranes. We also examined the effect of GUN on the mechanical properties of muscles as an indication of the metabolic condition of the SM at birth. METHODS: Isolated TT membrane from SM of GUN rats were used to study lipid/protein content and protein stability by differential scanning calorimetry. The effect of GUN on the SM mechanical properties was determined in isolated Extensor Digitorum Longus (EDL) muscle. RESULTS: We demonstrate that compared to control, GUN in the new-born produces; i) decreases body weight; ii) diminution in SM mass; iii) decreases the formation of TT membranes; iv) expresses TT membrane proteins with higher thermal stability. The TT membrane expression of GLUT-4 in GUN offspring was twice that of controls. The isolated EDL of GUN offspring was 20% stronger as measured by contractile force and more resistant to fatigue relative to controls. CONCLUSION: These results provide the first evidence of adaptive changes of the SM in new-borns exposed to severe gestational food restriction. The effects of GUN on muscle at birth are the first step toward detrimental SM metabolic function, contributing to the physiopathology of metabolic diseases in adulthood.

Detección de entermotoxina termolabil de Escherichia coli por nefelometrímia de rayo láser / Detection of thermolabile enterotoxin of Escherichia coli by laser ray nephelometry

Uno de los agentes etiológicos más frecuentes en la producción de diarrea es Escherichia coli enterotoxígena, que produce dos tipos de toxinas, la termolábil (ETL) y la termoestable (ETS). Ambas ejercen su acción por estímulo de la adenilciclasa, la cual produce alteraciones en la absorción y secreción de agua y electrólitos en las células del intestino. Para poder detectar la presencia de las toxinas se han empleado pruebas que presentan dificultades para su empleo sistemático en un laboratorio clínico, como son ensayo en asa ligada de intestino de conejo, cultivo de tejidos, hemólisis pasiva, etc. En este trabajo se presenta un método de aplicación más sencilla y que a la vez parece confiable, y en el que se recurre a un nefelómetro de rayo láser. El desarrollo del método incluyó: producción de antisuero antitoxina termolábil en conejos a partir de una cepa toxígena conocida (H-10407); titulación de niveles óptimos de toxina y anticuerpo, y ensayo de temperaturas y tiempos más convenientes para el sistema de reacción inmunoquímico. Se describen en detalle las etapas del método y se presentan los resultados obtenidos con el aparato utilizado. Se compararon los resultados con un método considerado de referencia, que es el asa aislada de conejo. Se concluye que el método es accesible y más sencillo que varios de los métodos descritos anteriormente, y que además es confiable y reproducible