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31.
Neuropeptide Y has been proposed to play a major role in the hypothalamic regulation of feeding behavior through the activation of specific, central NPY receptor(s). In an effort to design small molecule antagonists of NPY receptors, we have synthesized a series of substituted dipeptides based on defined pharmacophores, previously identified by us and others as essential for the interaction with the peptide receptors. GI264879A behaves as a functional antagonist of Y1 receptors while displaying no binding selectivity for the different NPY receptor subtypes. We demonstrate here that administration of GI264879A to rats causes a significant decrease in food intake and body weight partly through a mechanism dependent on the integrity of the vagus nerve.  相似文献   
32.
Finding small non-peptide molecules for G protein-coupled receptors (GPCR) whose endogenous ligands are peptides, is a very important task for medicinal chemists. Over the years, compounds mimicking peptide structures have been discovered, and scaffolds emulating peptide backbones have been designed. In our work on GPCR ligands, including cholecystokinin receptor-1 (CCKR-1) agonists, we have employed benzodiazepines as a core structure. Looking for ways to reduce molecular weight and possibly improve physical properties of GPCR ligands, we embarked on the search for molecules providing similar scaffolds to the benzodiazepine with lower molecular weight. One of our target core structures was 1,4-dihydro-[1,4]diazepine-5,7-dione. There was not, however, a known synthetic route to such molecules. Here we report the discovery of a simple and concise method for synthesis of 2-[6-(1H-indazol-3-ylmethyl)-5,7-dioxo-4-phenyl-4,5,6,7-tetrahydro-[1,4]diazepin-1-yl]-N-isopropyl-N-phenyl-acetamide as an example of a compound containing the tetrahydrodiazepine-5,7-dione core. Compounds from this series were tested in numerous GPCR assays and demonstrated activity at melanocortin 1 and 4 receptors (MC1R and MC4R). Selected compounds from this series were tested in vivo in Peptide YY (PYY)-induced food intake. Compounds dosed by intracerebroventricular and oral routes reduced PYY-induced food intake and this effect was reversed by the cyclic peptide MC4R antagonist SHU9119.  相似文献   
33.
For subsets of colorectal adenocarcinoma (CRC) patients, nuclear accumulation of p53 (p53(nac)) and Bcl-2 expression are prognostic indicators. To understand their role in the progression of CRC we evaluated 90 CRCs and their contiguous adenomatous components (CAdCs) for immunohistochemical expression of these markers. In general, p53(nac) and Bcl-2 expression was significantly increased when comparing normal colonic epithelia to CAdCs and CRCs. Thirteen (14%) CAdCs that demonstrated p53(nac) continued to express p53(nac) in their contiguous CRCs. A similar trend was observed in Bcl-2 expression in that the majority of CAdCs expressing Bcl-2 continued to express it in their matching CRCs (39/44). Patients whose CAdCs and their contiguous CRCs demonstrate p53(nac) had shorter median survival (35.9 months) than those patients whose CAdCs and CRCs did not (80.56 months). However, patients whose CAdCs had p53(nac) and lacked Bcl-2 expression had the lowest median survival (15.74 months) when compared with patients whose CAdCs did not demonstrate p53(nac) but had increased expression of Bcl-2 (71.77 months). These findings suggest that in those adenomas that demonstrate p53(nac) but lack Bcl-2 expression, their contiguous CRCs are more likely to be aggressive as they progress.  相似文献   
34.
Rat adrenal glands contain cell surface high-affinity receptors for several peptide hormones. Receptors for IGF-I were abundant in this tissue, but receptors for insulin were relatively scarce. The behavior of adrenal membrane IGF-I receptors in radioligand binding assays was similar to the behavior of IGF-I receptors from other tissues, with a KD congruent to 6.2 x 10(-9) M. Covalent cross-linking studies with [125I]IGF-I revealed an IGF-I receptor alpha-subunit with Mr congruent to 135,000 on dodecyl sulfate polyacrylamide gel electrophoresis under reducing conditions, as well as a smaller radiolabeled peptide, Mr = 116,000. In contrast, little binding of [125I]insulin to adrenal membranes was observed and no labeling occurred in cross-linking studies using [125I]insulin. These results contrast with the findings of whole-body autoradiographic studies that indicated substantial binding of [125I]insulin to adrenal glands and suggest that IGF-I, rather than insulin, may play a critical role in the growth and development of the adrenal gland.  相似文献   
35.
The eastern oyster (Crassostrea virginica), has experienced dramatic declines throughout its range, and most U.S. states along the Atlantic and Gulf of Mexico coasts have restoration programs. Oyster restoration in the Hudson River Estuary has been a focus of management agencies for over two decades. The present project was initiated in 2013 after sampling for replacement of the Tappan Zee bridge determined live oysters would be lost during bridge construction, thus requiring mitigation measures. Preliminary studies identified three areas for pilot studies to inform the design of full-scale efforts. A pilot study involving deployment of oyster shell-filled gabions and two styles of Reef Balls, found all substrates supported oyster recruitment and growth but there were higher oyster densities on gabions. Some of the gabions, however, failed structurally necessitating a need for new design. For full-scale restoration, a total of 422 modified gabions and 881 Mini-Bay style Reef Balls were deployed across three sites which totaled approximately 2.4 ha (6 ac) in seafloor area. Both substrate types were heavily colonized by oysters and several other species at all three sites, essentially duplicating the findings of the pilot study. The final monitoring event in 2020 indicated a total of approximately 5.8 million live oysters were on the substrates deployed in 2018. This mitigation effort was the largest oyster habitat restoration project in, or north of, the New York Harbor region in recent decades based on restoration area and several oyster metrics of early success.  相似文献   
36.
An important characteristic of tumors is that they at some point in their development overcome the surveillance of the immune system. Tumors secrete exosomes, multivesicular bodies containing a distinct set of proteins that can fuse with cells of the circulating immune system. Purified exosomes from TS/A breast cancer cells, but not non-exosomal fractions, inhibit (at concentrations of nanograms per ml protein) IL-2-induced natural killer (NK) cell cytotoxicity. The dietary polyphenol, curcumin (diferuloylmethane), partially reverses tumor exosome-mediated inhibition of natural killer cell activation, which is mediated through the impairment of the ubiquitin-proteasome system. Exposure of mouse breast tumor cells to curcumin causes a dose-dependent increase in ubiquitinated exosomal proteins compared to those in untreated TS/A breast tumor cells. Furthermore, exosomes isolated from tumor cells pretreated with curcumin have a much attenuated inhibition of IL-2 stimulated NK cell activation. Jak3-mediated activation of Stat5 is required for tumor cytotoxicity of IL-2 stimulated NK cells. TS/A tumor exosomes strongly inhibit activation of Stat5, whereas the tumor exosomes isolated from curcumin-pretreated tumor cells have a lowered potency for inhibition of IL-2 stimulated NK cell cytotoxicity. These data suggest that partial reversal of tumor exosome-mediated inhibition of NK cell tumor cytotoxicity may account for the anti-cancer properties of curcumin.  相似文献   
37.
38.
In this study we describe the sociodemographic characteristics of people participating in a clinical trial on the safety and immunogenicity of a H5N1 influenza vaccine and we identify the main motivations for joining it.  相似文献   
39.
Involvement of rabphilin-3A-like (RPH3AL), or Noc2, the potential effector of Ras-associated binding proteins Rab3A and Rab27A in the regulation of exocytotic processes in the endocrine pancreas has been demonstrated in experimental models. Noc2 expression together with other regulatory molecules of the exocytotic machinery in human tissues, however, has not been studied. We evaluated immunohistochemical expression of the key molecules of the exocytotic machinery, Noc2, Rab3A, Rab27A, and RIM2, together with the characteristic islet cell hormones, insulin and glucagon in normal and endocrine tumor tissues of human pancreas. Normal pancreatic islets were stained for all of these proteins and showed strong cytoplasmic localization. A similar pattern of strong cytoplasmic expression of these proteins was observed in the majority of endocrine tumors. By contrast, the exocrine portions of normal appearing pancreas completely lacked Rab27A staining and showed decreased expression of the proteins, Noc2, Rab3A, and RIM2. The staining pattern of Noc2 and Rab27A was similar to the staining pattern of glucagon-producing cells within the islets. The concomitant expression of Noc2 with these molecules suggests that Noc2 may serve as an effector for Rab3A and Rab27A and that it is involved in the regulation of exocytosis of the endocrine pancreas in humans.  相似文献   
40.
Phylogenetic analysis of cichlid fishes using nuclear DNA markers   总被引:7,自引:2,他引:5  
The recent explosive adaptive radiation of cichlids in the great lakes of Africa has attracted the attention of both morphologists and molecular biologists. To decipher the phylogenetic relationships among the various taxa within the family Cichlidae is a prerequisite for answering some fundamental questions about the nature of the speciation process. In the present study, we used the random amplification of polymorphic DNA (RAPD) technique to obtain sequence differences between selected cichlid species. We then designed specific primers based on these sequences and used them to amplify template DNA from a large number of species by the polymerase chain reaction (PCR). We sequenced the amplified products and searched the sequences for indels and shared substitutions. We identified a number of such characters at three loci-- DXTU1, DXTU2, and DXTU3--and used them for phylogenetic and cladistic analysis of the relationships among the various cichlid groups. Our studies assign an outgroup position to Neotropical cichlids in relation to African cichlids, provide evidence for a sister-group relationship of tilapiines to the haplochromines, group Cyphotilapia frontosa with the lamprologines of Lake Tanganyika, place Astatoreochromis alluaudi to an outgroup position with respect to other haplochromines of Lakes Victoria and Malawi, and provide additional support for the monophyly of the remaining Lake Victoria haplochromines and the Lake Malawi haplochromines. The described approach holds great promise for further resolution of cichlid phylogeny.   相似文献   
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