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排序方式: 共有3435条查询结果,搜索用时 22 毫秒
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Mr S. B. Bidiwala M. S. Mansour C. K. Stengel S. A. Klein S. M. Carroll S. C. Koenig A. H. Desoky G. R. Tobin C. Maldonado J. H. Barker 《Medical & biological engineering & computing》1998,36(5):621-626
Investigations into the changes that occur in microvasculature following the surgical procedure called delay have brought
about the need for a computer system capable of quantifying the morphological features of a full microvascular network in
terms of average vessel length, diameter, and tortuosity. Both the formulaic conventions that have been developed to measure
these quantities as well as their implementation in the form of a HP-9000/UNIX based computer software system that we developed
specifically for this purpose are discussed. Reliability studies performed using the final system to measure the microcirculatory
network of a mouse latissmus dorsi muscle (LDM) showed 95% confidence intervals within 5% of means and coefficients of variability
within 7% of means for all quantities measured in large (150–300 μm), medium (50–150 μm), and small (<50 μm) diameter vessels.
These variations were significantly smaller than the changes that were observed in a preliminary study comparing these microvascular
network parameters before and after delay in the hairless mouse LDM, showing the proposed quantification methods to be well
suited to the study of the microvascular changes following delay. It is hoped that the formulaic conventions, implementation
process and reliability data will provide a useful comparison for other researchers interested in measuring similar features
of microcirculatory networks. 相似文献
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Frataxin is reduced in Friedreich ataxia patients and is associated with mitochondrial membranes 总被引:17,自引:8,他引:17
Campuzano V; Montermini L; Lutz Y; Cova L; Hindelang C; Jiralerspong S; Trottier Y; Kish SJ; Faucheux B; Trouillas P; Authier FJ; Durr A; Mandel JL; Vescovi A; Pandolfo M; Koenig M 《Human molecular genetics》1997,6(11):1771-1780
Friedreich ataxia is a progressive neurodegenerative disorder caused by
loss of function mutations in the frataxin gene. In order to unravel
frataxin function we developed monoclonal antibodies raised against
different regions of the protein. These antibodies detect a processed 18
kDa protein in various human and mouse tissues and cell lines that is
severely reduced in Friedreich ataxia patients. By immunocytofluorescence
and immunocytoelectron microscopy we show that frataxin is located in
mitochondria, associated with the mitochondrial membranes and crests.
Analysis of cellular localization of various truncated forms of frataxin
expressed in cultured cells and evidence of removal of an N-terminal
epitope during protein maturation demonstrated that the mitochondrial
targetting sequence is encoded by the first 20 amino acids. Given the
shared clinical features between Friedreich ataxia, vitamin E deficiency
and some mitochondriopathies, our data suggest that a reduction in frataxin
results in oxidative damage.
相似文献
25.
CP Schaecher KA Groesch 《American journal of reproductive immunology (New York, N.Y. : 1989)》2006,55(6):405-405
Background: Control of mRNA stability is an essential regulatory process in eukaryotic gene expression. HuR, a 3'UTR mRNA binding protein, can protect AU-rich mRNA from degradation in response to stresses. PlGF, an angiogenic growth factor, contains two consensus AU-rich sites suggesting that under normal conditions HuR may protect PlGF mRNA from degradation. Trophoblast expression of PlGF is significantly decreased in preeclampsia and by hypoxia in vitro . We hypothesize that decreased levels of cytoplasmic HuR may contribute to decreased PlGF expression in hypoxic and preeclamptic trophoblast.
Methods: Western blots were used to determine relative effects of in vitro hypoxia on HuR protein expression and subcellular localization in trophoblast. Immunohistochemistry was used to compare HuR expression patterns in trophoblast of preeclamptic and normal placentae.
Results: Cytoplasmic expression of HuR was decreased 1.4 fold in the cytoplasm and 1.2 fold in the nucleus of JEG3 cells. A shift in HuR was more apparent in primary trophoblast with a greater than 2-fold decrease in the cytoplasm and a 1.4 fold decrease in the nucleus following 24 hr of hypoxia. Immunohistochemical analyses detected HuR expression in near term trophoblast in situ . However, this technical approach did not detect a significant change in HuR expression between normal and preeclamptic trophoblast.
Conclusions: HuR expression is decreased in hypoxic trophoblast, at least in vitro , which may provide a causal link to decreased PlGF mRNA expression. Down regulation of trophoblast PlGF expression is thought to contribute to the pathophysiology associated with preeclampsia including the relative lack of perfusion of the placenta and systemic renal effects. 相似文献
Methods: Western blots were used to determine relative effects of in vitro hypoxia on HuR protein expression and subcellular localization in trophoblast. Immunohistochemistry was used to compare HuR expression patterns in trophoblast of preeclamptic and normal placentae.
Results: Cytoplasmic expression of HuR was decreased 1.4 fold in the cytoplasm and 1.2 fold in the nucleus of JEG3 cells. A shift in HuR was more apparent in primary trophoblast with a greater than 2-fold decrease in the cytoplasm and a 1.4 fold decrease in the nucleus following 24 hr of hypoxia. Immunohistochemical analyses detected HuR expression in near term trophoblast in situ . However, this technical approach did not detect a significant change in HuR expression between normal and preeclamptic trophoblast.
Conclusions: HuR expression is decreased in hypoxic trophoblast, at least in vitro , which may provide a causal link to decreased PlGF mRNA expression. Down regulation of trophoblast PlGF expression is thought to contribute to the pathophysiology associated with preeclampsia including the relative lack of perfusion of the placenta and systemic renal effects. 相似文献
26.
J I Koenig 《Toxicologic pathology》1989,17(2):256-265
The hypothalamus receives neuronal afferents from numerous sources including inputs from limbic structures, such as the amygdala and hippocampus, and from brainstem regions involved in the regulation of the cardiovascular system and other autonomic functions. These afferents using a vast array of neurotransmitters and neuropeptides influence the activity of the hypothalamic neurons which synthesize and secrete the hypothalamic releasing and release-inhibiting factors into the hypophyseal portal circulatory system. The afferents can modulate the activity of the hypothalamic neurons by forming synapses on the neuronal cell body, on the nerve terminals in the median eminence or both. The chemicals most frequently used as neurotransmitters are the biogenic amines, including the catecholamines (norepinephrine, dopamine and epinephrine), serotonin, acetylcholine and gamma-aminobutyric acid (GABA). The stimulatory influence of norepinephrine, serotonin, and acetylcholine on the secretion of corticotropin (ACTH) in rodents and man will be discussed, whereas GABA exerts an inhibitory effect on the secretion of ACTH in both man and rodents. These effects appear to be mediated by changes in the secretion of the corticotropin-releasing hormone (CRH) and vasopressin into the hypophyseal portal circulation. Numerous neuropeptides appear to alter the secretion of ACTH in the rat. We will discuss the stimulatory actions of neuropeptide Y (NPY), angiotensin II, and peptides of immune cell origin on the secretion of ACTH and CRH. The opioid peptides inhibit the secretion of CRH into the portal blood, however, they exert a potent stimulatory effect on prolactin secretion in the rat and man.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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A new method to assess attachment representations in children by applying a story completion procedure in doll play (SCPDP) is presented. Transmission and continuity of attachment were tested in 28 German families by using the Strange Situation procedure (SS) with the mother and her infant, the Adult Attachment Interview (AAI) with the mother when the child is 5 years old, and the attachment representations (SCPDP) of the 6-year-olds. Relying on the twofold distinction (secure/insecure), results revealed a significant continuity of attachment from 1 to 6 years of age, and a correspondence between maternal AAI and child's attachment quality in SS, as well as a correspondence between maternal AAI and the 6-year-olds' attachment representations. Using configural frequency analysis, we found continuity in patterns of security and insecurity when looking across the measures of infant and pre-school attachment and maternal adult attachment. Processes underlying the high match of mothers' and children's attachment representations are discussed. 相似文献
29.
目的:探讨物理课程在高等医药类专业教育中的作用与地位。方法:对全国部分城市不同类别医院从业医务工作者进行调查,综合国际医学教育标准和我国现实医学教育以及医疗服务行业状况进行分析。结果:探讨了我国高等医药类专业教育中物理课程的设置及目标与定位问题,给出了明确的课程定位与设置标准。结论:现代医学高等教育不应忽视或淡化物理课程在医学人才培养中素质教育和专业水平提高的积极作用与基础地位,在有限的学时空间内合理安排基础性内容和与专业素质培养相关的应用内容。 相似文献