نتایج جستجو برای: mature gonads
تعداد نتایج: 71376 فیلتر نتایج به سال:
Fragmented 18-day chick embryo gonads were explanted on synthetic media in the presence of hCG added to 24 h cultures at the beginning (0 h) and to 48 h cultures, only after 24 h or at 0 and 24 h. The production of seven steroids was assayed by RIA and compared to that of control cultures containing no hCG. The levels were expressed as in vitro production per gonad (after deduction of the non-e...
A unique acid-soluble basic protein was detected in the testes of sexually mature rats and a number of other mammalian species. This protein was not found in comparable acid extracts prepared from many other rat organs or from the testes of juvenile rats. It makes its appearance only after spermatids are evident in normally developing testes and is absent from the gonads of male rats rendered a...
Effects are examined of chronic exposure to cadmium sulfate(5, 1, 0.5 and 0.1 mg Cd 1-l) on gametogenesis of mature sea urchins Strongylocentrotus intermedius, and on the development of their offspring. Embryogenesis in uncontaminated sea water (33 %O S) was observed up to the early pluteus. At 5 mg Cd I-', test animals died within several h; at 1 mg Cd 1-l within several d; at 0.5 mg Cd I-' wi...
Bone is a peculiar connective tissue which functionally interacts with many other organs and tissues, including bone marrow, lymphoid tissue, kidney, adipose tissue, endocrine pancreas, brain and gonads. Bone functions are accomplished by three principal cell types: the osteoblasts, cells of mesenchymal origin having osteogenic functions, the osteoclasts, giant multinucleated cells arising from...
Introduction The term teratoma, derived from the Greek teraton meaning “a monster”, was coined by Virchow in 1869 for a tumour originating in the sacrococcygeal region. Teratomas are composed of multiple tissues foreign to the organ or site in which they arise. Although teratomas are sometimes defined as having the three embryonic layers (endoderm, mesoderm, and ectoderm), recent classification...
Teratoma is a rare tumor, containing structures originating from all three germinal layers. The most frequent location of teratoma is the gonads. Orbital teratoma is extremely rare. In 1969, Jensen reported that only 40 cases of orbital teratoma existed in the world. We describe a rare case of orbital teratoma in a 15-day girl who presented with marked proptosis of the left eye. The eyeball was...
Germ cells are the precursors of the sperm and oocytes and hence are critical for survival of the species. In mammals, they are specified during fetal life, migrate to the developing gonads and then undergo a critical period during which they are instructed, by the soma, to adopt the appropriate sexual fate. In a fetal ovary, germ cells enter meiosis and commit to oogenesis, whereas in a fetal ...
Phytoestrogens are produced by plants and may cause endocrine disruption in vertebrates. The present study hypothesizes that phytoestrogen exposure of female Siamese fighting fish (Betta splendens) may disrupt endogenous steroid levels, change agonistic behavior expression, and potentially also disrupt oocyte development. However, only the pharmacologic dose of β-sitosterol had a significant ef...
Self-renewing stem cells are pools of undifferentiated cells, which are maintained in cellular niche environments by distinct tissue-specific signalling pathways. In Drosophila melanogaster, female germline stem cells (GSCs) are maintained in a somatic niche of the gonads by BMP signalling. Here we report a novel function of the Drosophila kinase Bällchen (BALL), showing that its cell autonomou...
Cellular infiltrations forming lymphoid-like aggregates were previously observed in gonads of two turtle species exhibiting temperature-dependent sex determination (TSD): at hatching in Chelydra serpentina; at and after hatching in Emys orbicularis. We show here that such aggregates are also present in gonads of Testudo graeca by the end of embryonic development, suggesting that their occurrenc...
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