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G. Meyer G. Bottà G. Fedele D. Cremaschi 《Cellular and molecular life sciences : CMLS》1995,51(11):1045-1051
In intact tissue, [d-Ala2,MePhe4, Gly-ol5] enkephalin (10–5 M;-ligand), diminsihed short-circuit current (Isc) and increased water, Na+ and Cl– net fluxes in vitro under open circuit conditions; it also inhibitedL-valine absorption andL-valine-dependent variations of short-circuit current (Isc, val). Naloxone (10–6 M) antagonized these effects. In the absence of the muscularis and myenteric plexus this enkephalin or morphine (-ligand) reduced Isc and Isc, val. These enkephalin effects occurred at different times. Different concentrations of enkephalin were tested for their effects on Isc, val. [d-Ala2,d-Leu5] enkephalin (mainly a -ligand) significantly decreased Isc but not Isc, val. The reduction ofL-valine absorption does not depend on the effects on basal ion transport. Interaction of opioids with-receptors located in the submucosal plexus and/or in the epithelial cell accounts for this reduction. This enkephalin effect seems to be at least partially under the control of the myenteric plexus. 相似文献
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Bone marrow cells adopt the phenotype of other cells by spontaneous cell fusion 总被引:217,自引:0,他引:217
Terada N Hamazaki T Oka M Hoki M Mastalerz DM Nakano Y Meyer EM Morel L Petersen BE Scott EW 《Nature》2002,416(6880):542-545
Recent studies have demonstrated that transplanted bone marrow cells can turn into unexpected lineages including myocytes, hepatocytes, neurons and many others. A potential problem, however, is that reports discussing such 'transdifferentiation' in vivo tend to conclude donor origin of transdifferentiated cells on the basis of the existence of donor-specific genes such as Y-chromosome markers. Here we demonstrate that mouse bone marrow cells can fuse spontaneously with embryonic stem cells in culture in vitro that contains interleukin-3. Moreover, spontaneously fused bone marrow cells can subsequently adopt the phenotype of the recipient cells, which, without detailed genetic analysis, might be interpreted as 'dedifferentiation' or transdifferentiation. 相似文献
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Summary The purification and crystallization of bacterial -amylase are described. It is not identical with pancreas -amylase, but its action on starch is the same. 相似文献
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In this paper we demonstrate the existence of a cytoplasmic processing step, never before described, involving both the pre-ribosomal
subunits in the sea urchin Paracentrotus lividus. Northern-blot hybridization, primer extension, S1 mapping experiments and in situ hybridizations allowed us to demonstrate
that cytoplasmic processed particles are successively re-imported into the nucleus where maturation of their RNAs is completed
prior to being exported to the cytoplasm. Our findings lead to the proposal of a new model of ribosome maturation and shuttling. 相似文献
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Anita Kothari Nadia Hamel Jo-Anne MacDonald Mechthild Meyer Benita Cohen Dorothy Bonnenfant 《Systemic Practice and Action Research》2014,27(2):123-137
Social network analysis is a potentially useful reflective tool that could be used by public health practitioners to assess the overall composition of their networks, strengthen collaborations with other community partners, and evaluate network function. The purpose of this paper is to report on public health practitioners’ experiences with social network analysis. Thirteen public health practitioners, each associated with their own advocacy-oriented community collaboration, participated in the study. Specifically, the intervention consisted of social network analysis output (social network analysis measures and sociograms) and a facilitated discussion to stimulate reflection on the respondents’ professional networks. Semi-structured interviews were conducted two weeks later to solicit participants’ reactions to the sociograms and the accompanying measures, and elicit thoughts about how social network analysis might have an impact on their work. Participants commented on ways in which social network analysis could be applied in practice, such as using sociograms to raise awareness of the nature of current networks, as a planning and evaluation tool, to identify gaps, and to assess the degree of sustainability of current networks. 相似文献
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Redband trout Oncorhynchus mykiss gairdneri in the Columbia River Basin of western North America occupy desert and montane streams with variable habitat conditions. In general, desert streams are lower in gradient and elevation, contain less large substrate and more silt substrate, are less shaded by overhead vegetation, and have higher summer water temperature than montane streams. Consequently, we assessed whether the relationships between biotic and abiotic factors and the occurrence and abundance of redband trout in southwestern Idaho differed between desert and montane streams (<25 m mean width). Increased occurrence of redband trout in desert streams was most strongly related to increased stream shading and decreased amounts of silt substrate, followed by increased amounts of cobble/boulder substrate and absence of piscivorous fish (i.e., smallmouth bass Micropterus dolomieui and northern pikeminnow Ptychocheilus oregonensis ). In montane streams, increased occurrence of redband trout was most strongly related to decreased site elevation and increases in cobble/boulder substrate, followed by decreases in stream gradient and width. Furthermore, occurrence of redband trout decreased in desert streams at mean summer (June–August) water temperature (Temp smr ) >16 °C, whereas for montane streams, occurrence increased at Temp smr >9 °C. Redband trout density in desert streams was most strongly related to higher stream order (i.e., headwater streams), increased stream shading, and increased amounts of cobble/boulder substrate. In montane streams, redband trout density was not well explained by any stream conditions, but stream shading had the strongest positive relationship with density. Redband trout density was negatively related to Temp smr in desert streams, but the relationship was weak for montane streams. That environmental conditions related to the occurrence and abundance of redband trout differ between desert and montane streams is important for fisheries managers who manage these disparate populations occurring in such close proximity to each other. 相似文献