Myasthenia gravis (MG) is an autoimmune disease targeting the skeletal muscle acetylcholine receptor (AChR). Although the autoantigen is present in the thymus, it is not tolerated in MG patients. In addition, the nature of the cell bearing the autoantigen is controversial. To approach these questions, we used two lineages of transgenic mice in which the beta-galactosidase (beta-gal) gene is und...

introduction: the morphology and ultrastructure of germinal epithelum basement memberane (bm) in patients with non-obstructive azoospermia was studied by means of transmision electron microscipy. materials and methods: 10 biopsies of testis tissue from patients with non-obstructive azoospermia referred to royan institute as patients group and 5 biopsies from patients with prostatic cancer as co...

BACKGROUND The thymus provides an optimal cellular and humoral microenvironment for cell line committed differentiation of haematopoietic stem cells. The immigration process requires the secretion of at least one peptide called thymotaxine by cells of the reticulo-epithelial (RE) network of the thymic stromal cellular microenvironment. The thymic RE cells are functionally specialised based on t...

Myopericytomas are rare, slow-growing benign perivascular tumors most commonly arising within the superficial subcutaneous soft tissues of the lower extremity. They represent one of several related perivascular tumors of myoid lineage with similar morphology and shared immunohistochemical profile including positive staining for smooth muscle actin. Histologically, myopericytoma exhibit concentr...

Using a quantitative enzyme immunoassay, Thy-1 antigen expressed by a rat myoid cell line R615B2 was detected mainly on the cell surface at a single cell stage, whereas at the stage of forming myotubes, Thy-1 was found predominantly in the cytoplasm. The muscle specific creatine kinase activity also increased in association with the shift of Thy-1 from the cell surface to the cytoplasm, suggest...

Androgens act to stimulate spermatogenesis through androgen receptors (ARs) on the Sertoli cells and peritubular myoid cells. Specific ablation of the AR in either cell type will cause a severe disruption of spermatogenesis. To determine whether androgens can stimulate spermatogenesis through direct action on the peritubular myoid cells alone or whether action on the Sertoli cells is essential,...

The immunohistochemical localization of actin, vimentin and tubulin in adult ovine and bovine seminiferous tubules was studied at both the light and electron microscopical levels, using an improved methodical protocol. alpha-smooth muscle actin and structural F-actin were found to be present in myoid peritubular cells. Structural F-actin also occurs in Sertoli cells at three localizations; 1) A...

In human long-term marrow cultures connective tissue-forming stromal cells are an essential cellular component of the adherent layer where granulomonocytic progenitors are generated from week 2 onward. We have previously found that most stromal cells in confluent cultures were stained by monoclonal antibodies directed against smooth muscle-specific actin isoforms. The present study was carried ...

Background: Nicotine as a toxic agent in cigarette has detrimental effects on reproduction. The aim of this study was to evaluate effects of of nicotine on germ and somatic cells in adult mouse testis. Materials and Methods: Male mice were divided into four groups. Group A or controls, groups of B, C and D were treated with nicotine intraperitoneally in doses of 0.1, 0.2 and 0.4 mg/100 g body w...