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Hausegger KA; Cragg AH; Lammer J; Lafer M; Fluckiger F; Klein GE; Sternthal MH; Pilger E 《Radiology》1994,190(1):199
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Despite sufficient iodine supply, goiter continues to be of considerable surgical significance in formerly endemic countries. It now appears that iodine deficiency and increased thyrotropin stimulation are not the only causes of goiter. Xenotransplantation of human thyroid tissue onto nude mice allowed study of the regulation of growth and function in human goiter tissue. Grafts of human thyroid tissue growing in nude mice could be shown to react to endogenous mouse thyrotropic stimulation and suppression. 131I autoradiographs of xenotransplanted goiter tissue showed as marked a heterogeneity as did the original goitrous tissue prior to transplantation. There was no firm correlation between the morphologic appearance of a follicle and its iodine metabolism. Scintigraphically "cold" and "hot" goiter tissue differed from each other quantitatively but not qualitatively; i.e., both "hot" and "cold" tissue were composed of metabolically active and nonactive follicles. Iodine organification was not completely suppressible by thyroxine treatment; this indicates autonomous functional activity. The distribution of proliferating tissue labeled by 3-H-thymidine did not parallel the distribution of functionally active tissue labelled by 131I. Thyroxine treatment did not completely inhibit 3-H-thymidine incorporation, indicating autonomous growth. Thus, our pathogenetic concept of goiter formation is based on three mainstays: (1) goiter heterogeneity, (2) autonomy of growth and function, and (3) dissociation of growth and function in human goiter tissue. Thus, the surgeon dealing with goiter ought to remove all pathologically altered tissue, i.e., nodular tissue, irrespective of its appearance on scintiscans. 相似文献
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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
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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