首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 859 毫秒
1.
2.
3.
4.
5.
Responses to human CGRP, adrenomedullin (ADM), and proadrenomedullin NH2-terminal 20 peptide (PAMP) were studied in small human thymic arteries. CGRP, ADM, and PAMP produced concentration-dependent vasodilator responses in arteries preconstricted with the thromboxane mimic U-46619. Responses to ADM and PAMP were attenuated, whereas responses to CGRP were not altered by endothelial denudation. Inhibitors of nitric oxide synthase and guanylyl cyclase attenuated responses to ADM and PAMP but not to CGRP. The CGRP1 receptor antagonist CGRP(8-37) attenuated responses to CGRP and ADM but not to PAMP. Responses to CGRP were reduced by SQ-22536 and Rp-cAMPS, inhibitors of adenylyl cyclase and PKA. These data suggest that responses to CGRP and ADM are mediated by CGRP(8-37)-sensitive receptors and that the endothelial ADM receptor induces vasodilation by a nitric oxide-guanylyl cyclase mechanism, whereas a smooth muscle CGRP receptor signals by a cAMP-dependent mechanism. A different endothelial receptor recognizes PAMP and signals by a nitric oxide-dependent mechanism.  相似文献   

6.
Social scientists have not integrated relevant knowledge from the biological sciences into their explanations of human behavior. This failure is due to a longstanding antireductionistic bias against the natural sciences, which follows on a commitment to the view that social facts must be explained by social laws. This belief has led many social scientists into the error of reifying abstract analytical constructs into entities that possess powers of agency. It has also led to a false nature-culture dichotomy that effectively undermines the place of biology in social scientific explanation. Following the principles of methodological individualism, we show how behavioral explanations supported by data and theory from the neurosciences can be used to correct the errors of reificationist thinking in the social sciences. We outline a mechanistic approach to the explanation of human behavior with the hope that the biological sciences will begin to find greater acceptance among social scientists.  相似文献   

7.
Summary A monospecific antibody to a plasminogen Kringle 4-binding tetramer protein of human blood, tetranectin, was applied to various human endocrine tissues employing the peroxidase-antiperoxidase staining technique. Endocrine cells with a known protein or glycoprotein hormonal production such as chromophils (pituitary), follicular and parafollicular cells (thyroid), chief cells (parathyroid), hepatocytes (liver), islet cells (pancreas) and ganglion cells of the adrenal medulla displayed a convincing, positive staining reaction for tetranectin, which varied from cell to cell within the different tissues. The liver showed a distinct and universal reaction within almost all hepatocytes, thus raising suspicion of producing the bulk of tetranectin to the blood. Tetranectin has recently been characterized as a lectin-like protein with amino acid sequence homology to the core protein of a rat chondrosarcoma proteoglycan. Proteoglycans have been demonstrated in secretory granules of rat pituitary and pancreatic islet cells, where they probably serve as modulators in hormonal production. The granular, cytoplasmic immunohistochemical localization of tetranectin demonstrated in this study combined with the fact that tetranectin is known to attach to plasminogen and promote plasminogen activation catalysed by tissue plasminogen activator suggests that this protein might have a dual function, serving both as a regulator in the seretion of certain hormones and as a participant in the regulation of the limited proteolysis, which is considered important for the activation of prohormones.  相似文献   

8.
Testosterone and cortisol figure prominently in the research literature having to do with human competition. In this review, we track the history of this literature, concentrating particularly on major theoretical and empirical contributions, and provide commentary on what we see as important unresolved issues. In men and women, athletic competition is typically associated with an increase in testosterone (T) and cortisol (C). Hormone changes in response to non-athletic competition are less predictable. Person (e.g., power motivation, mood, aggressiveness, social anxiety, sex, and baseline levels of T and C) and context (e.g., whether a competition is won or lost, the closeness of the competition, whether the outcome is perceived as being influenced by ability vs. chance, provocations) factors can influence hormone responses to competition. From early on, studies pointed to a positive relationship between T and dominance motivation/status striving. Recent research, however, suggests that this relationship only holds for individuals with low levels of C – this is the core idea of the dual-hormone hypothesis, and it is certain that the broadest applications of the hypothesis have not yet been realized. Individuals differ with respect to the extent to which they embrace competition, but the hormonal correlates of competitiveness remain largely unexplored. Although rapid increases in both T and C associated with competition are likely adaptive, we still know very little about the psychological benefits of these hormonal changes. Administration studies have and will continue to contribute to this inquiry. We close with a discussion of what, we think, are important methodological and mechanistic issues for future research.  相似文献   

9.
Microbes, warfare, religion, and human institutions   总被引:1,自引:0,他引:1  
A significant number of practicing microbiologists are not aware of the historical impact of infectious agents on the development of human institutions. Microbes have played a profound role in warfare, religion, migration of populations, art, and in diplomacy. Boundaries of nations have changed as a result of microbial diseases. Infectious agents have terminated some kingdoms and elevated others. There is a need for microbiologists to have a historical perspective of some of the major ways in which a pathogen may influence civilized populations. Conditions may exist in contemporary society for a repeat of some of the kinds of plagues suffered by previous societies. The purpose of this paper is to review examples of situations where pathogenic microbes have forced societal modifications on centers of human population.  相似文献   

10.
There appears to be only one possible site for the production of an amidated peptide in the human proenkephalin sequence; this will give rise to the peptide named metorphamide. Since amidation of peptides is commonly an activation step in the synthesis of regulatory peptides, we have examined the levels and form of immunoreactivity to metorphamide in human post-mortem adrenal and phaeochromocytoma extracts. In three out of four post-mortem adrenal extracts, and in each of the two phaeochromocytoma extracts examined, there was 3-4 times more immunoreactivity to the carboxy-terminus of pro-enkephalin, Met-enkephalin(Arg6,Phe7), than to metorphamide. The metorphamide immunoreactivity was shown in each extract to measure only the amidated octapeptide according to gel exclusion and reverse-phase chromatography data. The implications for processing of proenkephalin in human adrenal are indicated.  相似文献   

11.
A human IAP-family gene, apollon, expressed in human brain cancer cells.   总被引:17,自引:0,他引:17  
IAP is a family of protein that has baculovirus IAP repeat (BIR) domains and inhibits apoptosis. We found a human IAP family gene, which we named Apollon, encoding a huge protein (530 kDa) that contains a single BIR domain and a ubiquitin-conjugating enzyme domain, that is a human homolog of BRUCE. Apollon protein was expressed in four of six brain cancers (gliomas), and one of five ovarian cancers in 38 human cancer cell lines that we examined. Among the brain cancer cell lines, SNB-78 expressed a high level of Apollon, and this cell line shows resistance against various anticancer drugs. Treating SNB-78 cells with antisense oligonucleotide against Apollon reduced the expression of Apollon protein, and significantly sensitized the cells to apoptosis induced by cisplatin and camptothecin. These results suggest that Apollon protects SNB-78 cells from undergoing apoptosis and, at least in part, plays a role in tumorigenesis and drug resistance of this cell line.  相似文献   

12.
Polycystins, calcium signaling, and human diseases   总被引:9,自引:0,他引:9  
Autosomal dominant polycystic kidney disease (ADPKD) is a major, inherited nephropathy affecting over 1:1000 of the worldwide population. It is a systemic condition with frequent hepatic and cardiovascular manifestations in addition to the progressive development of fluid-filled cysts from the tubules and collecting ducts of affected kidneys. The pathogenesis of cyst formation is currently thought to involve increased proliferation of epithelial cells, mild dedifferentiation, and fluid accumulation. In the past decade, study of ADPKD led to the discovery of a unique family of highly complex proteins, the polycystins. Loss-of-function mutations in either of two polycystin proteins, polycystin-1 or polycystin-2, give rise to ADPKD. These proteins are thought to function together as part of a multiprotein complex that may initiate Ca2+ signals, directing attention to the regulation of intracellular Ca2+ as a possible misstep that participates in cyst formation. Here we review what is known about the Ca2+ signaling functions of polycystin proteins and focus on findings that have significantly advanced our physiological insight. Special attention is paid to the recently discovered role of these proteins in the mechanotransduction of the renal primary cilium and the model it suggests.  相似文献   

13.
Peroxisomes, lipid metabolism, and human disease   总被引:2,自引:0,他引:2  
In the past few years, much has been learned about the metabolic functions of peroxisomes. These studies have shown that peroxisomes play a major role in lipid metabolism, including fatty acid β-oxidation, etherphospholipid biosynthesis, and phytanic acid α-oxidation. This article describes the current state of knowledge concerning the role of peroxisomes in these processes, especially in relation to various peroxisomal disorders in which there is an impairment in peroxisomal lipid metabolism.  相似文献   

14.
The evolution of human speech and syntax, which appear to be the defining characteristics of modern human beings, is discussed. Speech depends on the morphology of the mouth, tongue, and larynx which yield the human «vocal tract», and neural mechanisms that facilitate the perception of speech and make possible the control of the articulatory gestures that underly speech. The neural mechanisms that underly human syntax may have derived by means of the Darwinian process of preadaption from the structures of the brain that first evolved to facilitate speech motor control. Recent data consistent with this theory are presented; deficits in the comprehension of syntax of normal aged people are correlated with a slowdown in speech rate.  相似文献   

15.
This paper examines some of the philosophical and scientific relationships involving self-control, voluntary control, and psychophysiologic self-regulation. The role of biofeedback in mediating conscious and unconscious processes is explored. Demonstrations of superior voluntary control and its relationship to belief, confidence, and expectation are examined. Biofeedback demonstrates the potential of control to oneself, creating confidence in one's ability to establish enhanced and peak performance in athletics, education, and psychophysiologic therapy. Emphasis is placed on the power of images in all human functioning, and in enhancing human potential.Presidential address presented at the meetings of the Biofeedback Society of America, March 23, 1986, San Francisco.  相似文献   

16.
The authors analyse and assess the Universal Draft Declaration on Bioethics and Human Rights published by UNESCO. They argue that the Draft has two main weaknesses. It unnecessarily confines the scope of bioethics to life sciences and their practical applications. And it fails to spell out the intended role of human dignity in international ethical regulation.  相似文献   

17.
18.
Fc receptors for IgA on human B, and human non-B, non-T lymphocytes.   总被引:6,自引:0,他引:6  
Recently, receptors for IgA were demonstrated on subpopulations of human T lymphocytes. In this report, TNP-modified ox erythrocytes coated with the IgA myeloma MOPC-315 were used to detect IgA receptor-bearing lymphocytes within the human non T cell lymphocyte population. A mean of 5.3% (range 2.9 to 12.4%) of E-rosette negative human lymphocytes bound IgA-coated indicator cells. Blocking studies with soluble IgA, IgG, and IgM demonstrated that the IgA receptors on the non-T cell populations were separate and distinct from the Fc-receptors for IgG and IgM. Fractionation of the non-T lymphocytes on anti-human (Fab)2 columns into sIg+ and sIg- populations or by rosetting with EAC to provide CRL+ and CRL- populations demonstrated that Fc-IgA receptors were present on a subpopulation of sIg+, CRL+ lymphocytes, and also on sIg- (non-T, non-B) lymphocytes.  相似文献   

19.
20.
I describe an integrative social‐evolutionary model for the adaptive significance of the human oxytocinergic system. The model is based on a role for this hormone in the generation and maintenance of social familiarity and affiliation across five homologous, functionally similar, and sequentially co‐opted contexts: mothers with offspring, female and male mates, kin groups, individuals with reciprocity partners, and individuals within cooperating and competing social groups defined by culture. In each situation, oxytocin motivates, mediates and rewards the cognitive and behavioural processes that underlie the formation and dynamics of a more or less stable social group, and promotes a relationship between two or more individuals. Such relationships may be positive (eliciting neurological reward, reducing anxiety and thus indicating fitness‐enhancing effects), or negative (increasing anxiety and distress, and thus motivating attempts to alleviate a problematic, fitness‐reducing social situation). I also present evidence that testosterone exhibits opposite effects from oxytocin on diverse aspects of cognition and behaviour, most generally by favouring self‐oriented, asocial and antisocial behaviours. I apply this model for effects of oxytocin and testosterone to understanding human psychological disorders centrally involving social behaviour. Reduced oxytocin and higher testosterone levels have been associated with under‐developed social cognition, especially in autism. By contrast, some combination of oxytocin increased above normal levels, and lower testosterone, has been reported in a notable number of studies of schizophrenia, bipolar disorder and depression, and, in some cases, higher oxytocin involves maladaptively ‘hyper‐developed’ social cognition in these conditions. This pattern of findings suggests that human social cognition and behaviour are structured, in part, by joint and opposing effects of oxytocin and testosterone, and that extremes of such joint effects partially mediate risks and phenotypes of autism and psychotic‐affective conditions. These considerations have direct implications for the development of therapies for alleviating disorders of social cognition, and for understanding how such disorders are associated with the evolution of human cognitive‐affective architecture.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号