Michael B. Sporn

Bio: Michael B. Sporn is an academic researcher from Dartmouth College. The author has contributed to research in topics: Transforming growth factor & Transforming growth factor beta. The author has an hindex of 157, co-authored 559 publications receiving 94605 citations. Previous affiliations of Michael B. Sporn include Cornell University & Reata Pharmaceuticals.

Biological Activity and Metabolism of the Retinoid Axerophthene (Vitamin A Hydrocarbon)

Abstract: Biological properties of axerophthene, the hydrocarbon analog of retinol, have been studied both in vitro and in vivo . In tracheal organ culture axerophthene reversed keratinization caused by deficiency of retinoid in the culture medium; its potency was of the same order of magnitude as that of retinyl acetate. Axerophthene supported growth in hamsters fed vitamin A-deficient diets although less effectively than did retinyl acetate. Axerophthene was considerably less toxic than was retinyl acetate when administered repeatedly in high doses to rats. Administration of an equivalent p.o. dose of axerophthene caused much less deposition of retinyl palmitate in the liver than did the same dose of retinyl acetate, while a greater level of total retinoid was found in the mammary gland after administration of axerophthene.

Localization of Benzo]a]pyrene-3H and Alterations in Nuclear Chromatin Caused by Benzo[a]pyrene-Ferric Oxide in the Hamster Respiratory Epithelium

Abstract: The intratracheal instillation of benzo[α]pyrene (BP)-Fe2O3 in the Syrian golden hamster caused a number of changes in nuclear structure. A selective increase in the cross-sectional area of nuclei of basal cells was observed in multiple focal areas in the tracheal epithelium. This increase represented an enlargement in the cross-sectional area of euchromatin and a dispersion of the heterochromatin. In short-term organ culture of tracheas, incubation with BP-3H caused labeling of nuclear and cytoplasmic sites in mucous, basal, and ciliated cells. Quantitative light microscopic autoradiography revealed that prior in vivo administration of unlabeled BP caused a subsequent increase in the in vitro binding of BP-3H to epithelial cells. The total binding of BP-3H to epithelial cells was inhibited either by the addition of 7, 8-benzoflavone to the incubation medium or by incubation at 0°. These results suggest that enzymatic activation of BP must occur before BP can be bound. The nuclear localization of BP-3H was primarily in the heterochromatin, as determined by electron microscopic autoradiography.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

The pathogenesis of atherosclerosis: a perspective for the 1990s

Abstract: Atherosclerosis, the principal cause of heart attack, stroke and gangrene of the extremities, is responsible for 50% of all mortality in the USA, Europe and Japan. The lesions result from an excessive, inflammatory-fibroproliferative response to various forms of insult to the endothelium and smooth muscle of the artery wall. A large number of growth factors, cytokines and vasoregulatory molecules participate in this process. Our ability to control the expression of genes encoding these molecules and to target specific cell types provides opportunities to develop new diagnostic and therapeutic agents to induce the regression of the lesions and, possibly, to prevent their formation.

TGF-beta signal transduction.

Abstract: The transforming growth factor beta (TGF-beta) family of growth factors control the development and homeostasis of most tissues in metazoan organisms. Work over the past few years has led to the elucidation of a TGF-beta signal transduction network. This network involves receptor serine/threonine kinases at the cell surface and their substrates, the SMAD proteins, which move into the nucleus, where they activate target gene transcription in association with DNA-binding partners. Distinct repertoires of receptors, SMAD proteins, and DNA-binding partners seemingly underlie, in a cell-specific manner, the multifunctional nature of TGF-beta and related factors. Mutations in these pathways are the cause of various forms of human cancer and developmental disorders.