A new species of Thelastomathidae (Nematoda) a parasite of Neocurtilla claraziana Saussure (Orthoptera, Gryllotalpidae) in Argentina

Gryllophila cephalobulata n. sp. (Nematoda, Thelastomatidae) a parasite of the mole cricket Neocurtilla claraziana (Orthoptera, Gryllotalpidae) isolated in Buenos Aires Province, is described and illustrated. It is characterized by cuticle annulated all along the length of the body; the first ring has 4 lobules, the second one has 14 lobules, the others rings are simple, the stoma is short and has 4 small teeth, the genital papillae are arranged in 5 pairs, of which 3 pairs are preanal and 2 pairs are postanal. The tail appendage of the male is long and filiform.Centro de Estudios Parasitológicos y de Vectore

A new species of Thelastomathidae (Nematoda) a parasite of Neocurtilla claraziana Saussure (Orthoptera, Gryllotalpidae) in Argentina

Gryllophila cephalobulata n. sp. (Nematoda, Thelastomatidae) a parasite of the mole cricket Neocurtilla claraziana (Orthoptera, Gryllotalpidae) isolated in Buenos Aires Province, is described and illustrated. It is characterized by cuticle annulated all along the length of the body; the first ring has 4 lobules, the second one has 14 lobules, the others rings are simple, the stoma is short and has 4 small teeth, the genital papillae are arranged in 5 pairs, of which 3 pairs are preanal and 2 pairs are postanal. The tail appendage of the male is long and filiform.Centro de Estudios Parasitológicos y de Vectore

A new species of Thelastomathidae (Nematoda) a parasite of Neocurtilla claraziana Saussure (Orthoptera, Gryllotalpidae) in Argentina

Gryllophila cephalobulata n. sp. (Nematoda, Thelastomatidae) a parasite of the mole cricket Neocurtilla claraziana (Orthoptera, Gryllotalpidae) isolated in Buenos Aires Province, is described and illustrated. It is characterized by cuticle annulated all along the length of the body; the first ring has 4 lobules, the second one has 14 lobules, the others rings are simple, the stoma is short and has 4 small teeth, the genital papillae are arranged in 5 pairs, of which 3 pairs are preanal and 2 pairs are postanal. The tail appendage of the male is long and filiform.Centro de Estudios Parasitológicos y de Vectore

Islet adaptive changes to fructose-induced insulin resistance: β-cell mass, glucokinase, glucose metabolism, and insulin secretion

β-Cell mass, hexokinase/glucokinase (HK/GK) activity, glucose metabolism and insulin secretion were studied in the islets of rats with fructose-induced insulin resistance (IR). Normal male Wistar rats were fed a standard commercial diet and water without (control, C) or with 10% fructose-rich diet (FRD) for 3 weeks. Blood glucose (strips), triglyceride (commercial kit), and insulin (RIA) levels were measured at the time of death. Glucose-induced insulin release, glucose metabolism (14CO2 and 3H2O production from D-[U-14C]- and D-[5-3H]-glucose) and HK/GK activity (G-6-P production), transcription (RTPCR), protein expression (Western blot), and cellular compartmentalization were measured in isolated islets (collagenase digestion). FRD rats presented normoglycemia but impaired glucose tolerance, hypertriglyceridemia, hyperinsulinemia, and increased HOMA-IR index. In these rats, β-cell mass decreased significantly by 33%, with a 44% increase in the percentage of apoptotic cells. Glucose-induced insulin release and islet glucose metabolism were higher in FRD rats. While GK activity (total and cytosolic fraction) and protein expression were significantly higher in FRD islets, HK showed no change in any of these parameters. Our results demonstrate that the changes induced by dietary-induced IR upon β-cell function and mass are strongly conditional on the nutrient model used. In our model (intact animals with impaired glucose tolerance), GK activity increases through mechanisms previously shown only in vitro or under highly hyperglycemic conditions. Such an increase plays a pivotal role in the adaptive increased release of insulin in response to IR, even in the presence of marked β-cell mass reduction.Centro de Endocrinología Experimental y Aplicad

Rol del estrés oxidativo en la disfunción pancreática inducida por una dieta rica en sacarosa

La dieta rica en sacarosa (DRS) induce un cuadro de alteración plurimetabólica que incluye estrés oxidativo (EO) y un aumento en la concentración sérica de ácidos grasos y de leptina, afectando la función y la masa de las células b pancreáticas. No es claro el rol del EO en la patogenia de estos cambios. Objetivo: determinar si la falla insular detectada en los animales alimentados durante 3 semanas con DRS está desencadenada por un aumento del EO.Facultad de Ciencias Médica

Impaired endocrine-metabolic homeostasis: Underlying mechanism of its induction by unbalanced diet

To characterize the intrinsic mechanism by which sucrose induces β-cell dysfunction. Normal rats received for 3 weeks a standard diet supplemented with 10% sucrose in the drinking water (high sucrose (HS)) with/out an antioxidant agent (R/S α-lipoic acid). We measured plasma glucose, insulin, triglyceride, leptin, and lipid peroxidation levels; homeostasis model assessment (HOMA)-insulin resistance (HOMA-IR) and HOMA for β-cell function (HOMA-β) indexes were also determined. Insulin secretion, β-cell apoptosis, intracellular insulin and leptin mediators, and oxidative stress (OS) markers were also measured in islets isolated from each experimental group. HS rats had increased plasma triglyceride, insulin, leptin, and lipid peroxidation (OS marker) levels associated with an insulin-resistant state. Their islets developed an initial compensatory increase in glucose-induced insulin secretion and mRNA and protein levels of β-cell apoptotic markers. They also showed a significant decrease in mRNA and protein levels of insulin and leptin signaling pathway mediators. Uncoupling protein 2 (UCP2), peroxisome proliferator-activated receptor (PPAR)-α and -δ mRNA and protein levels were increased whereas mRNA levels of Sirtuin-1 (Sirt-1), glutathione peroxidase, and catalase were significantly lower in these animals. Development of all these endocrine-metabolic abnormalities was prevented by co-administration of R/S a-lipoic acid together with sucrose. OS may be actively involved in the mechanism by which unbalanced/unhealthy diet induces β-cell dysfunction. Since metabolic-endocrine dysfunctions recorded in HS rats resembled those measured in human pre-diabetes, knowledge of its molecular mechanism could help to develop appropriate strategies to prevent the progression of this metabolic state toward type 2 diabetes (T2D).Centro de Endocrinología Experimental y Aplicad

Relación entre la angiogénesis y el efecto potenciador del INGAP-PP sobre la función β pancreática

Tanto la diferenciación celular β en el embrión como el mantenimiento de su masa y función en el adulto dependen de la presencia de células endoteliales y del factor de crecimiento endotelial vascular (VEGF-A). Por otro lado, la administración del pentadecapéptido derivado del INGAP (INGAP-PP) a ratas adultas aumenta la masa y función de las células β insulares. El objetivo del trabajo fue determinar si el efecto positivo que ejerce el INGAP-PP sobre la masa y función celular β depende de un efecto primario sobre la neogénesis vascular del islote.Facultad de Ciencias Médica

Rol del estrés oxidativo en la disfunción pancreática inducida por una dieta rica en sacarosa

La dieta rica en sacarosa (DRS) induce un cuadro de alteración plurimetabólica que incluye estrés oxidativo (EO) y un aumento en la concentración sérica de ácidos grasos y de leptina, afectando la función y la masa de las células b pancreáticas. No es claro el rol del EO en la patogenia de estos cambios. Objetivo: determinar si la falla insular detectada en los animales alimentados durante 3 semanas con DRS está desencadenada por un aumento del EO.Facultad de Ciencias Médica

Relación entre la angiogénesis y el efecto potenciador del INGAP-PP sobre la función β pancreática

Tanto la diferenciación celular β en el embrión como el mantenimiento de su masa y función en el adulto dependen de la presencia de células endoteliales y del factor de crecimiento endotelial vascular (VEGF-A). Por otro lado, la administración del pentadecapéptido derivado del INGAP (INGAP-PP) a ratas adultas aumenta la masa y función de las células β insulares. El objetivo del trabajo fue determinar si el efecto positivo que ejerce el INGAP-PP sobre la masa y función celular β depende de un efecto primario sobre la neogénesis vascular del islote.Facultad de Ciencias Médica

Expression of islet neogenesis-associated protein in islets of normal hamsters

The aim of the present study was to test the possible presence and expression of islet neogenesis-associated protein (INGAP) in islet cells of normal adult hamsters. Pancreata from normal male Syrian hamsters were removed to perform the following studies. (i) Western blot analysis using the cytosolic fraction from homogenates of isolated islets, exocrine tissue and whole pancreas, and rabbit INGAP-specific antibody. (ii) Immunohistochemical identification of INGAP-positive cells in fixed sections of intact pancreata, fresh and 72 h cultured islets (isolated by collagenase digestion), and smears of exocrine pancreatic cells, using the same INGAP-specific antibody and streptavidin-biotin complex. (iii) RT-PCR using total RNA extracted from isolated islets and from exocrine tissue as template, and a specific pair of primers. (iv) Control of the sequence of the PCR products. INGAP protein was identified by Western blot in the cytosolic fraction of homogenates from fresh isolated islets, exocrine cells and whole fresh pancreas. INGAP-immunopositive cells were observed in duct, exocrine and islet cells in either fixed intact or digested pancreatic tissue. INGAP mRNA was identified in samples of total RNA from fresh and cultured isolated islets and from exocrine cells. Our data demonstrate that INGAP is present and expressed in islets and in exocrine pancreatic cells of normal hamsters. The ubiquitous localization of INGAP suggests its possible role in the physiological process of islet growth and its protective effect upon streptozotocin-induced diabetes.Centro de Endocrinología Experimental y Aplicad