89 research outputs found
Rival's absorptive capacity and innovation performance: Mediating effect of the strategic orientation
Introduction. In the literature there are contradictory results on the effects of the evaluation of rival's absorptive capacity (RAC) on innovation performance (IP). Moreover, the incidence of strategic aspects in this relationship has not been explored. Objective. Analyze the mediating effects of the strategic orientation towards competition (SOC) and the strategic orientation towards innovation (SOI) on the RAC-IP relationship. Materials and methods. The hypothesis model was contrasted in a sample of medium and low-technology manufacturing firms and a sample of service firms. To achieve this, structural equations were used by the consistent partial least squares method. Results. It was found that only the SOC has a mediating effect, which is a total effect. Conclusions. The main contribution of this paper is the empirical evidence it provides which demonstrates that the evaluation of RAC has a positive effect on IP, although this effect is mediated by SOC. This helps to discern the controversy triggered by contradictory results yielded in previous studies. Therefore, this finding is in agreement with the theoretical stance which highlights the benefits derived from understanding RAC's strengths and weaknesses, and from the pressures exerted by rivals on their counterpart, which force the latter to be more innovativeIntroducción. En la literatura hay resultados contradictorios sobre los efectos de la evaluación de la capacidad de absorción del rival (CAR) sobre el desempeño innovador (DI). Tampoco, se ha explorado la incidencia de aspectos estratégicos sobre esa relación. Objetivo. Analizar los efectos mediadores de la orientación estratégica a la competencia (OEC) y a la innovación (OEI) en la relación entre CAR y DI. Materiales y métodos. El modelo de hipótesis se contrastó en una muestra de empresas manufactureras, de media y baja tecnología, y de servicios. Para ello, se utilizaron ecuaciones estructurales por el método de mínimos cuadrados. Resultados. Se encontró que únicamente la OEC tiene un efecto mediador el cual es total. Conclusiones. La principal contribución del artículo gira en torno al aporte de evidencia empírica que demuestra que la evaluación de la CAR tiene un efecto positivo sobre el DI, si bien está mediado por la OEC. Esto es importante porque ayuda a dilucidar la controversia suscitada por los resultados contradictorios que arrojaron estudios previos. Por lo tanto, este hallazgo concuerda con la postura teórica que resalta los beneficios que se derivan del entendimiento de las fortalezas y debilidades de la CAR, y de las presiones que ejercen los rivales sobre su contraparte, que la obligan a ser más innovadora
Leptolide improves insulin resistance in diet-induced obese mice
Producción CientíficaType 2 diabetes (T2DM) is a complex disease linked to pancreatic beta-cell failure and insulin resistance. Current antidiabetic treatment regimens for T2DM include insulin sensitizers and insulin secretagogues. We have previously demonstrated that leptolide, a member of the furanocembranolides family, promotes pancreatic beta-cell proliferation in mice. Considering the beneficial effects of leptolide in diabetic mice, in this study, we aimed to address the capability of leptolide to improve insulin resistance associated with the pathology of obesity. To this end, we tested the hypothesis that leptolide should protect against fatty acid-induced insulin resistance in hepatocytes. In a time-dependent manner, leptolide (0.1 µM) augmented insulin-stimulated phosphorylation of protein kinase B (PKB) by two-fold above vehicle-treated HepG2 cells. In addition, leptolide (0.1 µM) counteracted palmitate-induced insulin resistance by augmenting by four-fold insulin-stimulated phosphorylation of PKB in HepG2 cells. In vivo, acute intraperitoneal administration of leptolide (0.1 mg/kg and 1 mg/kg) improved glucose tolerance and insulin sensitivity in lean mice. Likewise, prolonged leptolide treatment (0.1 mg/kg) in diet-induced obese mice improved insulin sensitivity. These effects were paralleled with an ~50% increased of insulin-stimulated phosphorylation of PKB in liver and skeletal muscle and reduced circulating pro-inflammatory cytokines in obese mice. We concluded that leptolide significantly improves insulin sensitivity in vitro and in obese mice, suggesting that leptolide may be another potential treatment for T2DM.This research has been funded by Sociedad Española de Diabetes (Ayudas Investigación Básica 2014), Salud Castilla y León (BIO/VA40/15)Ministerio de Economía y Competitividad, (SAF2014-58702-C2-1-R),(SAF2014-58702-C2-2-R
Protective effects of epoxypukalide on pancreatic b-cells and glucose metabolism in STZ-induced diabetic mice
Producción CientíficaDiabetes is a consequence of a decrease on functional β-cell mass. We have recently demonstrated that epoxypukalide (Epoxy) is a natural compound with beneficial effects on primary cultures of rat islets. In this study, we extend our previous investigations to test the hypothesis that Epoxy protects β-cells and improves glucose metabolism in STZ-induced diabetic mice. We used 3-months old male mice that were treated with Epoxy at 200 μg/kg body weight. Glucose intolerance was induced by multiple intraperitoneal low-doses of streptozotocin (STZ) on 5 consecutive days. Glucose homeostasis was evaluated measuring plasma insulin levels and glucose tolerance. Histomorphometry was used to quantify the number of pancreatic β-cells per islet. β-cell proliferation was assessed by BrdU incorporation, and apoptosis by TUNEL staining. Epoxy treatment significantly improved glucose tolerance and plasma insulin levels. These metabolic changes were associated with increased β-cell numbers, as a result of a two-fold increase in β-cell proliferation and a 50% decrease in β-cell death. Our results demonstrate that Epoxy improves whole-body glucose homeostasis by preventing pancreatic β-cell death due to STZ-induced toxicity in STZ-treated mic
Chloro-Furanocembranolides from Leptogorgia sp. Improve Pancreatic Beta-Cell Proliferation
Type 2 diabetes (T2DM) is a complex disease linked to pancreatic beta-cell failure and insulin resistance. Current antidiabetic treatment regimens for T2DM include insulin sensitizers and insulin secretagogues. We have previously demonstrated that leptolide, a member of the furanocembranolides family, promotes pancreatic beta-cell proliferation in mice. Considering the beneficial effects of leptolide in diabetic mice, in this study, we aimed to address the capability of leptolide to improve insulin resistance associated with the pathology of obesity. To this end, we tested the hypothesis that leptolide should protect against fatty acid-induced insulin resistance in hepatocytes. In a time-dependent manner, leptolide (0.1 µM) augmented insulin-stimulated phosphorylation of protein kinase B (PKB) by two-fold above vehicle-treated HepG2 cells. In addition, leptolide (0.1 µM) counteracted palmitate-induced insulin resistance by augmenting by four-fold insulin-stimulated phosphorylation of PKB in HepG2 cells. In vivo, acute intraperitoneal administration of leptolide (0.1 mg/kg and 1 mg/kg) improved glucose tolerance and insulin sensitivity in lean mice. Likewise, prolonged leptolide treatment (0.1 mg/kg) in diet-induced obese mice improved insulin sensitivity. These effects were paralleled with an ~50% increased of insulin-stimulated phosphorylation of PKB in liver and skeletal muscle and reduced circulating pro-inflammatory cytokines in obese mice. We concluded that leptolide significantly improves insulin sensitivity in vitro and in obese mice, suggesting that leptolide may be another potential treatment for T2DMMinisterio de Ciencia e Innovación
(SAF2009-0839 and RTA 2015-00010-C03-02). ARDM acknowledges funding from IMBRAIN project
(FP7-REGPOT-2012-CT2012-31637-IMBRAIN) and from Cabildo de Tenerife (Agustín de Betancourt Programme).
A.B.G. would like to thank Convenio Universidad de Magallanes (Chile) and CSIC, project 2009CL0031,
for financial support
Multi-anti-parasitic activity of arylidene ketones and thiazolidene hydrazines against trypanosoma cruzi and Leishmania spp.
A series of fifty arylideneketones and thiazolidenehydrazines was evaluated against Leishmania infantum and Leishmania braziliensis. Furthermore, new simplified thiazolidenehydrazine derivatives were evaluated against Trypanosoma cruzi. The cytotoxicity of the active compounds on non-infected fibroblasts or macrophages was established in vitro to evaluate the selectivity of their anti-parasitic effects. Seven thiazolidenehydrazine derivatives and ten arylideneketones had good activity against the three parasites. The IC50 values for T. cruzi and Leishmania spp. ranged from 90 nM–25 μM. Eight compounds had multi-trypanocidal activity against T. cruzi and Leishmania spp. (the etiological agents of cutaneous and visceral forms). The selectivity of these active compounds was better than the three reference drugs: benznidazole, glucantime and miltefosine. They also had low toxicity when tested in vivo on zebrafish. Trying to understand the mechanism of action of these compounds, two possible molecular targets were investigated: triosephosphate isomerase and cruzipain. We also used a molecular stripping approach to elucidate the minimal structural requirements for their anti-T. cruzi activity
Frequency of cancer in children residing in Mexico City and treated in the hospitals of the Instituto Mexicano del Seguro Social (1996–2001)
BACKGROUND: The objective of this article is to present the frequency of cancer in Mexican children who were treated in the hospitals of the Instituto Mexicano del Seguro Social in Mexico City (IMSS-MC) in the period 1996–2001. METHODS: The Registry of Cancer in Children, started in 1996 in the IMSS-MC, is an on-going, prospective register. The data from 1996 through 2001 were analyzed and the different types of cancer were grouped according to the International Classification for Cancer in Children (ICCC). From this analysis, the general and specific frequencies by age and by sex were obtained for the different groups of neoplasms. Also, the frequency of the stage of the disease that had been diagnosed in cases of children with solid tumors was obtained. RESULTS: A total of 1,702 new cases of children with cancer were registered, with the male/female ratio at 1.1/1. Leukemias had the highest frequency with 784 cases (46.1%) and, of these, acute lymphoblastic leukemias were the most prevalent with 614 cases (78.3%). Thereafter, in descending order of frequency, were tumors of the central nervous system (CNST) with 197 cases (11.6%), lymphomas with 194 cases (11.4%), germinal cell tumors with 110 cases (6.5%), and bone tumors with 97 cases (5.7%). The highest frequency of cancer was found in the group of one to four year-olds that had 627 cases (36.8%). In all the age groups, leukemias were the most frequent. In the present work, the frequency of Hodgkin's disease (~4%) was found to be lower than that (~10%) in previous studies and the frequency of tumors of the sympathetic nervous system was low (2.3%). Of those cases of solid tumors for which the stage of the disease had been determined, 66.9% were diagnosed as being Stage III or IV. CONCLUSIONS: The principal cancers in the children treated in the IMSS-MC were leukemias, CNST, and lymphomas, consistent with those reported by developed countries. A 2.5-fold reduction in the frequency of Hodgkin's disease was found. Of the children, the stage of whose disease had been determined, two thirds were diagnosed as having advanced stages of the disease
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