共查询到20条相似文献,搜索用时 31 毫秒
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Culture, Medicine, and Psychiatry - 相似文献
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《生物化学与生物物理学报:癌评论》2001,1552(1):1-13
Breast carcinoma is one of the most common neoplasms in women and is a leading cause of cancer related deaths worldwide. In recent years improved diagnostic tools have made it possible to detect breast cancers at early, even pre-invasive stages leading to a significant decrease in breast cancer mortality rates over the past decades. The increased number of patients diagnosed with pre-invasive breast tumors opened up new avenues in research and new dilemmas in clinical practice, since our understanding of the pathophysiology of such lesions is just beginning to emerge. Part of the delay and difficulty with analyzing pre-invasive tumors including ductal carcinoma in situ has been due to the lack of appropriate techniques suitable for studies of small, frequently microscopic size tumors. Recently developed technologies such as DNA microarrays and SAGE (serial analysis of gene expression) have made it possible to obtain comprehensive gene expression profiles of breast carcinomas of all stages. The application of these genomics approaches in combination with the complete sequence of the human genome and extensive molecular epidemiological studies is likely to further our understanding of the molecular basis of mammary tumorigenesis and will identify targets for risk prediction, cancer prevention and treatment. 相似文献
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V M Dowding 《BMJ (Clinical research ed.)》1981,282(6265):683-686
A survey of the 20 698 singleton births occurring in one year to women resident in the Greater Dublin area provided information on birth weight, birth order, and social class. Low (less than or equal to 2500 g), suboptimal (less than or equal to 3000 g), and optimal (3001-4499 g) birth weights all showed a linear relation with social class. The incidence of low and suboptimal birth weight was highest in first, fifth, and subsequent births, and conversely optimal weight was commonest in second, third, and fourth births. Analysis indicated that a major part of the birth-order effect was attributable to social class. Birthweight categories give information which may be distorted when using mean weight alone. The ue of suboptimal and optimal weight offers the possibility of more accurate assessment of trends in performance, particularly in small samples, than does the conventional sole use of low birth weight. Low and suboptimal birth weights are uncommon in Dublin. 相似文献
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In Canadian society the influence of first birth timing on the subsequent birth interval has been eroded over time, as shown by the Canadian Fertility Survey of 1984. The influence of first birth timing is significant for second births among women married during the baby boom period, but not for those married thereafter. Religiosity, marital status, and place of residence are significant factors in second birth timing in Canada. 相似文献
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Meisetz and the birth of the KRAB motif 总被引:3,自引:0,他引:3
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SCAN is a protein domain frequently found at the N termini of proteins encoded by mammalian tandem zinc finger (ZF) genes, whose structure is known to be similar to that of retroviral gag capsid domains and whose multimerization has been proposed as a model for retroviral assembly. We report that the SCAN domain is derived from the C-terminal portion of the gag capsid (CA) protein from the Gmr1-like family of Gypsy/Ty3-like retrotransposons. On the basis of sequence alignments and phylogenetic distributions, we show that the ancestral host SCAN domain (ESCAN for extended SCAN) was exapted from a full-length CA gene from a Gmr1-like retrotransposon at or near the root of the tetrapod animal branch. A truncated variant of ESCAN that corresponds to the annotated SCAN domain arose shortly thereafter and appears to be the only form extant in mammals. The Anolis lizard has a large number of tandem ZF genes with N-terminal ESCAN or SCAN domains. We predict DNA binding sites for all Anolis ESCAN-ZF and SCAN-ZF proteins and demonstrate several highly significant matches to Anolis Gmr1-like sequences, suggesting that at least some of these proteins target retroelements. SCAN is known to mediate protein dimerization, and the CA protein multimerizes to form the core retroviral and retrotransposon capsid structure. We speculate that the SCAN domain originally functioned to target host ZF proteins to retroelement capsids. 相似文献
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Regulation of the hypothalamic-pituitary-adrenal axis in birth 总被引:1,自引:0,他引:1
In sheep an increase in fetal pituitary-adrenal function, reflected in rising concentrations of plasma ACTH and cortisol, is important in relation to fetal organ maturation and the onset of parturition. This review presents evidence that implicates the hypothalamic-pituitary-adrenal axis in the control of parturition and describes recent experiments that explore in detail the maturation of the fetal hypothalamus and pituitary in relation to fetal adrenal function. Recent improvements for the measurement of ACTH in unextracted plasma and the ability to maintain vascular catheters in chronically catheterized fetal sheep have enabled subtle changes in fetal ACTH concentrations to be detected. As a result of these advances it has now been established that the terminal rise in cortisol, which is responsible for the onset of parturition in sheep, is preceded by an increase in fetal plasma ACTH concentrations. This has led to the hypothesis that birth results from the sequential development of the fetal hypothalamic-pituitary-adrenal axis with the signal originating from the fetal brain. This increase in trophic drive to the fetal adrenal may result from changes in the responsiveness of the fetal pituitary gland to factors that stimulate the release of ACTH. Corticotropin releasing factor (CRF) and arginine vasopressin are two such factors that stimulate the secretion of ACTH and cortisol secretion in the chronically catheterized fetal sheep. The response to these factors increases with gestational age and is sensitive to glucocorticoid feedback. Furthermore, repeated administration of CRF to immature fetal sheep results in pituitary and adrenal activation and in some cases may lead to premature parturition.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Xylogenesis is a complex developmental process culminating in programmed cell death as a truly terminal differentiation event. In Arabidopsis, the availability of vascular-patterning mutants, and the identification of genes and their products that are involved in cell specification, secondary-wall deposition and lignification, are providing clues to the functions of some of the sequences in the large expressed sequence tag databases derived from the xylem-rich tissues of trees. An in vitro system, the Zinnia mesophyll cell system, provides an alternative system for those cell-biological experiments that are difficult to tackle in intact plants. In particular, a combination of molecular-genetic and cell-biological approaches has made possible the elucidation of some of the features of plant programmed cell death. 相似文献
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Freshwater MF 《Plastic and reconstructive surgery》2008,121(3):1071-2; author reply 1072