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.

Murine cysticercosis model: influence of the infection time and the time of treatment on the cysticidal efficacy of albendazole and praziquantel.

In the search of new alternatives for neurocysticercosis treatment, Taenia crassiceps ORF strain cysticerci have been used instead of T. solium for in vitro studies. Up to date, the main criteria for the use of the murine cysticercosis model for drug efficacy evaluation have not been assessed. The aim of the present study was to evaluate the influence of two of the main variables related to the in vivo efficacy: the length of drug treatment and the starting time of treatment after experimental infection, using albendazole (ABZ) and praziquantel (PZQ) as test drugs. Additionally, the relationship between the number of cysts and the parasite weight was assessed. For the study, female BALB/c mice were experimentally infected with T. crassiceps cysts. Three different post-infection periods (10, 20 and 30 days) and three different lengths of treatment with ABZ or PZQ (10, 20 and 30 days) were selected. The efficacy of each treatment was evaluated by comparison with a control group. Our results show that for in vivo efficacy studies, the best time to start the drug treatment is 10 days post-infection and that a minimum of 20 days of treatment is required when ABZ or PZQ are used as positive control. Moreover, in this model the parasite weight can be used as a rapid tool to measure the in vivo drug activity.

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.

Connexin 36 is expressed in beta and connexins 26 and 32 in acinar cells at the end of the secondary transition of mouse pancreatic development and increase during fetal and perinatal life.

To identify when during fetal development connexins (Cxs) 26 (Cx26) 32 (Cx32), and 36 (Cx36) begin to be expressed, as well as to characterize their spatial distribution, real time polymerase chain reaction and immunolabeling studies were performed. Total RNA from mouse pancreases at 13 and 18 days postcoitum (dpc) and 3 days postpartum (dpp) was analyzed. In addition, pancreatic sections of mouse at 13, 14, 15, 16, 18 dpc and 3 dpp and of rat at term were double labeled with either anti-insulin or anti-α-amylase and anti-Cx26 or -Cx32 or -Cx36 antibodies and studied with confocal microscopy. From day 13 dpc, Cxs 26, 32, and 36 transcripts were identified and their levels increased with age. At 13-14 dpc, Cxs 26 and 32 were localized in few acinar cells, whereas Cx36 was distributed in small beta cell clumps. From day 14 dpc onwards, the number of labeled cells and relative immunofluorescent reactivity of all three Cxs at junctional membranes of the respective cell types increased. Cxs 26 and 32 colocalized in fetal acinar cells. In rat pancreas at term, a similar connexin distribution was found. Relative Cxs levels evaluated by immunoblotting also increased (two-fold) in pancreas homogenates from day 18 dpc to 3 dpp. The early cell specific, wide distribution, and age dependent expression of Cxs 26, 32, and 36 during fetal pancreas ontogeny suggests their possible involvement in pancreas differentiation and prenatal maturation.

Functional expression and subcellular localization of the taurine transporter TauT in murine neural precursors.

Taurine addition to cultured embryonic neural precursor cells (NPC) significantly increased cell proliferation [Hernández-Benítez et al., 2010]. The medium used for NPC growing and proliferation is a fetal serum-free medium, and therefore, NPC become taurine depleted. Addition of taurine to the cultured medium fully replenished the cell taurine pool, suggesting the functional expression of a taurine transporter (TauT) in these cells. In the present study, TauT in NPC was functionally characterized and its protein expression and the subcellular distribution of immunoreactivity were determined. ³H-taurine uptake in NPC could be separated into a non-saturable component and a Na(+)/Cl⁻-dependent, saturable component. The saturable component showed an apparent 2:1:1 Na(+)/Cl⁻/taurine stoichiometry, a V(max) of 0.39 ± 0.04 nmol/mg protein/min, and a K(m) of 21.7 ± 2.6 µM. TauT in NPC was strongly inhibited by hypotaurine and ß-alanine (92 and 79%, respectively) and reduced (71%) by γ-aminobutyric acid. TauT protein is expressed in NPC as a single band of about 70 kDa. Essentially all (98.8%) of the neurosphere-forming cells were positive to TauT immunoreactivity. Immunolocalization visualized by confocal microscopy localized TauT predominantly at the cell membrane. TauT was also found at the cytosol and only occasionally at the nuclear membrane. This study represents the first characterization of TauT in NPC.

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