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 ...

We examined long bones from 42 human embryos and fetuses whose gestational ages ranged from 6 to 28 weeks. Bone rudiment sections were stained using a panel of monoclonal antibodies directed at antigens expressed by hematopoietic cells, endothelial cells, smooth muscle cells, fibro-blasts, and stromal cells, to describe the events preceding and accompanying the onset of hematopoiesis in the dia...

Androgen is essential for maintenance of spermatogenesis in the testis and for maturation of spermatozoa in the epididymis. The effects of androgen are mediated through its receptor (AR), the levels of which are, in turn, regulated by androgen. Previous studies have shown that AR concentrations in Leydig and Sertoli cells are differentially regulated during development. The aim of the present s...

The long slender retinal cones of fishes shorten in the light and elongate in the dark. Light-induced cone shortening provides a useful model for stuying nonmuscle contraction because it is linear, slow, and repetitive. Cone cells contain both thin (actin) and thick (myosinlike) filaments oriented parallel to the axis of contraction. This study examines the polarities of the cone's thin filamen...

Multilocular thymic cyst (MTC) and germ cell tumors are common diseases that impact the mediastinum. Correctly diagnosing these can be difficult because several other conditions mimic them. We report a male patient with MTC associated mediastinal seminoma. A needle biopsy of tumor revealed numerous epithelioid granulomas mimicked sarcoidosis or mycobacterial infection. However, large atypical c...