Estimation of Drug-effect in Use of Multi-tracer Autoradioqraphy - Effect of S-Adenosyl-L-Methionoie on Postischemic Brain Injury in Rat -

開始ページ、終了ページ: 冊子体のページ付

Sex of muscle stem cells does not influence potency for cardiac cell therapy

We have previously shown that populations of skeletal muscle-derived stem cells (MDSCs) exhibit sexbased differences for skeletal muscle and bone repair, with female cells demonstrating superior engrafting abilities to males in skeletal muscle while male cells differentiating more robustly toward the osteogenic and chondrogenic lineages. In this study, we tested the hypothesis that the therapeutic capacity of MDSCs transplanted into myocardium is influenced by sex of donor MDSCs or recipient. Male and female MDSCs isolated from the skeletal muscle of 3-week-old mice were transplanted into recipient male or female dystrophin-deficient (mdx) hearts or into the hearts of male SCID mice following acute myocardial infarction. In the mdx model, no difference was seen in engraftment or blood vessel formation based on donor cell or recipient sex. In the infarction model, MDSC-transplanted hearts showed higher postinfarction angiogenesis, less myocardial scar formation, and improved cardiac function compared to vehicle controls. However, sex of donor MDSCs had no significant effects on engraftment, angiogenesis, and cardiac function. VEGF expression, a potent angiogenic factor, was similar between male and female MDSCs. Our results suggest that donor MDSC or recipient sex has no significant effect on the efficiency of MDSC-triggered myocardial engraftment or regeneration following cardiac injury. The ability of the MDSCs to improve cardiac regeneration and repair through promotion of angiogenesis without differentiation into the cardiac lineage may have contributed to the lack of sex difference observed in these models. Copyright © 2009 Cognizant Comm. Corp

Photoelectric Emission from Interstellar Dust: Grain Charging and Gas Heating

We model the photoelectric emission from and charging of interstellar dust and obtain photoelectric gas heating efficiencies as a function of grain size and the relevant ambient conditions. Using realistic grain size distributions, we evaluate the net gas heating rate for various interstellar environments, and find less heating for dense regions characterized by R_V=5.5 than for diffuse regions with R_V=3.1. We provide fitting functions which reproduce our numerical results for photoelectric heating and recombination cooling for a wide range of interstellar conditions. In a separate paper we will examine the implications of these results for the thermal structure of the interstellar medium. Finally, we investigate the potential importance of photoelectric heating in H II regions, including the warm ionized medium. We find that photoelectric heating could be comparable to or exceed heating due to photoionization of H for high ratios of the radiation intensity to the gas density. We also find that photoelectric heating by dust can account for the observed variation of temperature with distance from the galactic midplane in the warm ionized medium.Comment: 50 pages, including 18 figures; corrected title and abstract field

Identification of plant genetic resources with high potential contribution to soil fertility enhancement in the Sahel, with special interest in fallow vegetation

The sandy soil in the Sahel is characterized as low inherent fertility, that is, having nutrient deficiency (total N and available P), low organic matter and high risk of erosion. Under the concept of integrated soil fertility management (ISFM), possible contribution of natural inhabitant plants to the improvement of soil fertility in the Sahel was evaluated. A broad variation in δ 15N values was observed among the plant species commonly found in cropland and fallow land of the Sahelian zone. Annual leguminous herbs, Cassia mimosoides (Caesalpiniaceae) and Alysicarpus ovalifolius (Papilionaceae), had low δ 15N values, showing their higher dependency on biological nitrogen fixation. They will be efficiently utilized as an extensive means of soil fertility management, for example, through more encouraged incorporation into the fallow vegetation. Ctenium elegans, Eragrostis tremula and Schizachyrium exile, greatly dominating annual grass species in the fallow land, though their δ 15N values were high, would contribute to the soil fertility by supplying a significant amount of organic matte

Developing cardiac and skeletal muscle share fast-skeletal myosin heavy chain and cardiac troponin-I expression

Skeletal muscle derived stem cells (MDSCs) transplanted into injured myocardium can differentiate into fast skeletal muscle specific myosin heavy chain (sk-fMHC) and cardiac specific troponin-I (cTn-I) positive cells sustaining recipient myocardial function. We have recently found that MDSCs differentiate into a cardiomyocyte phenotype within a three-dimensional gel bioreactor. It is generally accepted that terminally differentiated myocardium or skeletal muscle only express cTn-I or sk-fMHC, respectively. Studies have shown the presence of non-cardiac muscle proteins in the developing myocardium or cardiac proteins in pathological skeletal muscle. In the current study, we tested the hypothesis that normal developing myocardium and skeletal muscle transiently share both sk-fMHC and cTn-I proteins. Immunohistochemistry, western blot, and RT-PCR analyses were carried out in embryonic day 13 (ED13) and 20 (ED20), neonatal day 0 (ND0) and 4 (ND4), postnatal day 10 (PND10), and 8 week-old adult female Lewis rat ventricular myocardium and gastrocnemius muscle. Confocal laser microscopy revealed that sk-fMHC was expressed as a typical striated muscle pattern within ED13 ventricular myocardium, and the striated sk-fMHC expression was lost by ND4 and became negative in adult myocardium. cTn-I was not expressed as a typical striated muscle pattern throughout the myocardium until PND10. Western blot and RT-PCR analyses revealed that gene and protein expression patterns of cardiac and skeletal muscle transcription factors and sk-fMHC within ventricular myocardium and skeletal muscle were similar at ED20, and the expression patterns became cardiac or skeletal muscle specific during postnatal development. These findings provide new insight into cardiac muscle development and highlight previously unknown common developmental features of cardiac and skeletal muscle. © 2012 Clause et al

Chrono-Autoradiographic Method - Evaluation of Sequential Glucose Metabolism -

開始ページ、終了ページ: 冊子体のページ付

Validation of soil organic carbon dynamics model in the semi-arid tropics in Niger, West Africa

The fertility of sandy soils in the Sahelian zone (SZ) is extremely low. This poor soil fertility is one of the limiting factors of crop production in the SZ. Therefore, it is imperative to improve or to maintain soil fertility through various agricultural management methods. Further, it is well known that soil organic matter plays an important role in improving the physicochemical properties of these sandy infertile soils. Therefore, it is essential to develop a suitable tool for the appropriate evaluation of soil organic carbon (SOC) dynamics in the SZ. Therefore, the Rothamsted carbon model (Roth-C) was verified in 32 treatments of two long-term field experiments with and without crop residue application. These experiments were performed by ICRISAT. The performance of the model was evaluated by statistical methods using four indices (RMSE: root mean square error, LOFIT: lack of fit, r: correlation coefficient, and M: mean difference). As a result, the predicted SOC values in the casewithout crop residue management decreased with time in approximately 10 cultivated years. In contrast, in the case with crop residue application, the predicted SOC remained roughly equal to the initial SOC value during the term observed. Mostly, the Roth-C-modelled values agreed well with the actual value. RMSE and LOFIT, the statistical indicators of agreement between predicted and observed values, showed a significant conformity between the predicted and observed SOC values in all the 32 treatments. This fact means that Roth-C can estimate long-term SOC dynamics of several technical options that developed with short-term trials. Moreover the annual carbon requirement for SOC maintaining can be calculate if enough number of cases was estimated. And also analysis of regional carbon dynamics was made possible with using Roth-C model. It will contribute to show the sustainable development in SZ against global warming and other climatic changes

Rothamsted carbon model reveals technical options to maintain soil organic carbon under semi-arid climate

Soil organic matter in the Sahel is severely reduced by continuous cultivation. Reductions of soil organic matter decrease in turn soil productivity. Nonetheless, reports show that organic matter application in the Sahel improves crop yield. However, long-term effects of organic matter application on soil fertility have not been fully studied. In particular, it is essential to get information on organic matter decomposition and annual carbon requirement. Model simulation is suitable for evaluating long-term sustainability. The Rothamsted carbon model is convenient and has been recently validated for use in Sahelian conditions. Here, we studied the annual carbon requirement for sustainable soil organic carbon management in the Sahelian zone using datasets of short-term trials conducted in the Sahel. We estimated the long-term effect of various agricultural managements on soil organic carbon dynamics as one of the soil fertility indices. The 10-year soil organic carbon value changes were predicted by the Rothamsted carbon model for 59 treatments. Results show that, contrary to previous short-term experiments that indicated crop yield enhancement, these technical options also cause a decline in soil organic carbon if enough organic resource is not applied. Soil productivity should therefore decrease. The annual carbon requirement to maintain the soil organic carbon level is approximately 0.8 tons of carbon per hectar

Estimation of nitrogen flow within a village-farm model in Fakara region in Niger, Sahelian zone of West Africa

To determine the efficiency of utilization of organic matter in agricultural production, nitrogen flow was estimated within a village-farm model in the west of Niger, West Africa. Nitrogen was focused on in this study as it is known to be a major nutrient component of organic matter and one of the limiting nutrients in Sahelian soil. Local practices regarding the use of organic matter and pertinent information on traditional practices for soil fertility management were determined by interviews with local farmers. To estimate nitrogen flow in farmlands and consumption in the village through various activities, quantitative measurements of crop yield and organic amendment were carried out. Data on human and livestock excreta were taken from published reports. The size and classification of farmlands were as follows: 0.5 ha adjacent farmland, 1.6 ha threshing farmland, 6.0 ha transported-manure farmland, 5.5 ha corralling farmland, and 86.5 ha extensively managed farmland (EMF). Levels of nitrogen flow from these farmlands to the studied villages were 0.9, 2.9, 9.6, 15.2, and 94.2 Mg, while the flows to these farmlands were 14.6, 6.3, 13.7, 17.5, and 26.3 Mg, respectively. Upon calculation of nitrogen balance −8 kg ha−1 year−1 was estimated in EMF, but there was a positive balance in other types of farmland, which ranged from 4 to 262 kg ha−1 year−1, indicating inefficient use of nitrogen in the study area for crop production. The results indicated that nutrient flow in the study site was unequally distributed and nitrogen was not recycled. Therefore, efforts should be made to establish efficient utilization of available nutrients by reducing the loss from livestock feed and human consumption. At the same time, more research is needed to improve the management of EM