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Germinal Epithelium (germinal + epithelium)
Selected AbstractsGerminal epithelium, folliculogenesis, and postovulatory follicles in ovaries of rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (Teleostei, protacanthopterygii, salmoniformes)JOURNAL OF MORPHOLOGY, Issue 4 2007Harry J. Grier Abstract The rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), is a salmoniform fish that spawns once per year. Ripe females that had ovulated naturally, and those induced to ovulate using salmon gonadotropin-releasing hormone, were studied to determine whether follicles were forming at the time of spawning and to describe the process of folliculogenesis. After ovulation, the ovaries of postspawned rainbow trout were examined histologically, using the periodic acid-Schiff procedure, to stain basement membranes that subtend the germinal epithelium and to interpret and define the activity of the germinal epithelium. After spawning, the ovary contained a few ripe oocytes that did not ovulate, numerous primary growth oocytes including oocytes with cortical alveoli, and postovulatory follicles. The germinal epithelium was active in postspawned rainbow trout, as determined by the presence of numerous cell nests, composed of oogonia, mitotic oogonia, early diplotene oocytes, and prefollicle cells. Cell nests were separated from the stroma by a basement membrane continuous with that subtending the germinal epithelium. Furthermore, follicles containing primary growth oocytes were connected to the germinal epithelium; the basement membrane surrounding the follicle joined that of the germinal epithelium. After ovulation, the basement membrane of the postovulatory follicle was continuous with that of the germinal epithelium. We observed consistent separation of the follicle, composed of an oocyte and surrounding follicle cells, from the ovarian stroma by a basement membrane. The follicle is derived from the germinal epithelium. As with the germinal epithelium, follicle cells derived from it never contact those of the connective tissue stroma. As with epithelia, they are always separated from connective tissue by a basement membrane. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] Infusion of anti-nerve growth factor into the cisternum magnum of chick embryo leads to decrease cell production in the cerebral cortical germinal epitheliumEUROPEAN JOURNAL OF NEUROLOGY, Issue 2 2007F. Mashayekhi There has been considerable recent progress in understanding the processes involved in cerebral cortical development. Several mitogenic and trophic factors have been implicated in the processes of cortical cell proliferation and differentiation. Anti-nerve growth factor (NGF) antibody was administered to 15 days chick foetuses through the cisternum magnum. Control group received phosphate buffered saline (PBS). To identify cells born in the cerebral cortex at the time of antibody or PBS injection, 5,-bromo-2,- deoxyuridine was administered to the foetuses by intravenous injection into an outlying vein using micromanipulation. After injection, the foetuses were re-incubated for another 3 days. All the foetuses were collected on day 18, the brains fixed in paraformaldehyde, cut with a microtome and stained with methyl green pyronin and anti-NGF antibody. Quantitative measurements showed that the thickness of the germinal epithelium (GE) and cerebral cortex in the anti-NGF antibody injected foetuses was decreased when compared with normal control embryos. The number of cells produced in the GE of antibody injected foetuses was decreased when compared with normal control embryos. The results from this study using neutralizing antibody suggests that NGF is an important factor in cerebral cortical development, stimulating neuronal precursor proliferation. [source] The importance of cerebrospinal fluid on neural cell proliferation in developing chick cerebral cortexEUROPEAN JOURNAL OF NEUROLOGY, Issue 3 2006F. Mashayekhi Cerebrospinal fluid (CSF) is mainly produced by the choroid plexuses within the ventricles of the brain. The CSF circulates in a regular manner after the ventricular system and the choroids plexuses have developed, and the foramina in the fourth ventricle have opened to enable it to carry chemical information. CSF flows through the ventricular system passing over all regions of germinal activity. In this study, chick embryos were used to show the importance of CSF on neural cell proliferation in the developing cerebral cortex. The chick embryos were cannulated in situ with a fine capillary tube to drain CSF out of the ventricular system. At the same time, BrdU was administered to the embryos. After surgery the embryos were incubated for another 3 days. Quantitative measurements showed that the thicknesses of the germinal epithelium and cerebral cortex in CSF-drained embryos were less than those in the control group at the same age. The number of cells produced in the germinal epithelium of CSF-drained embryos was decreased when compared with the normal group. This study provides confirmatory evidence that CSF is important for neural cell proliferation and therefore normal development of the cerebral cortex. It is proposed that CSF is vital in controlling development of the cerebral cortex. [source] Fertility treatment in male cancer survivorsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue 4 2007Kirsten Louise Tryde Schmidt Summary The present study reviews the use of assisted reproductive technology in male cancer survivors and their partners. As antineoplastic treatment with chemotherapy or radiation therapy, has the potential of inducing impairment of spermatogenesis through damage of the germinal epithelium, many male cancer survivors experience difficulties in impregnating their partners after treatment. The impairment can be temporary or permanent. While many cancer survivors regain spermatogenesis months to years after treatment, some become infertile with a-, oligo- or azoospermia. An option to secure the fertility potential of young cancer patients is to cryopreserve semen before cancer treatment for later use. A desired pregnancy may be obtained in couples where the husband has a history of cancer, using assisted reproductive technology with either fresh or cryopreserved/thawed semen. Successful outcomes have been obtained with intrauterine insemination (IUI) as well as in vitro fertilization (IVF) with or without the use of intracytoplasmic sperm injection (ICSI). In conclusion, male cancer survivors and their partners who have failed to obtain a pregnancy naturally within a reasonable time frame after end of treatment should be referred to a fertility clinic. [source] Gonadogenesis in early developmental stages of Acipenser naccarii and influence of estrogen immersion on feminizationJOURNAL OF APPLIED ICHTHYOLOGY, Issue 1 2007G. Grandi Summary Gonad development processes and the effects of a single 8-hour immersion treatment with 17, -estradiol (E2, 400 ,g L,1) on sex differentation in the Adriatic sturgeon, Acipenser naccarii, were investigated. After migration of germ cells, gonadal ridges appeared in 16- to 18-day old larvae and undifferentiated gonads in 55- to 60-day old larvae. Putative ovaries with notches in the germinal epithelium and presumed testes with smooth germinal epithelium appeared in 180,185-day old juveniles. Ovaries with proliferating oogonia and early meiotic oocytes clusters were observed in 292-day old juveniles. Testes did not exhibit germ cell mitosis until 430 days of age. Developmental stages in E2 -treated animals closely followed those of controls up to 430 days. The treatment significantly increased the percentage of ovaries when administered to embryos about 1.5 day before hatching, while did not significantly altered the normal 1/1 sex ratio when administered to 1.5-day old pre-larvae and 10-day old larvae. It is likely that in A. naccarii exogenous E2 administration may act through a feedback mechanism of self-supporting steroid production and that steroids are the physiological inducers of sex differentiation, as in most teleosts. The E2 -immersion treatment, easier than time-consuming administration through food, could be a good approach to control sex differentiation and caviar production. [source] Germinal epithelium, folliculogenesis, and postovulatory follicles in ovaries of rainbow trout, Oncorhynchus mykiss (Walbaum, 1792) (Teleostei, protacanthopterygii, salmoniformes)JOURNAL OF MORPHOLOGY, Issue 4 2007Harry J. Grier Abstract The rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), is a salmoniform fish that spawns once per year. Ripe females that had ovulated naturally, and those induced to ovulate using salmon gonadotropin-releasing hormone, were studied to determine whether follicles were forming at the time of spawning and to describe the process of folliculogenesis. After ovulation, the ovaries of postspawned rainbow trout were examined histologically, using the periodic acid-Schiff procedure, to stain basement membranes that subtend the germinal epithelium and to interpret and define the activity of the germinal epithelium. After spawning, the ovary contained a few ripe oocytes that did not ovulate, numerous primary growth oocytes including oocytes with cortical alveoli, and postovulatory follicles. The germinal epithelium was active in postspawned rainbow trout, as determined by the presence of numerous cell nests, composed of oogonia, mitotic oogonia, early diplotene oocytes, and prefollicle cells. Cell nests were separated from the stroma by a basement membrane continuous with that subtending the germinal epithelium. Furthermore, follicles containing primary growth oocytes were connected to the germinal epithelium; the basement membrane surrounding the follicle joined that of the germinal epithelium. After ovulation, the basement membrane of the postovulatory follicle was continuous with that of the germinal epithelium. We observed consistent separation of the follicle, composed of an oocyte and surrounding follicle cells, from the ovarian stroma by a basement membrane. The follicle is derived from the germinal epithelium. As with the germinal epithelium, follicle cells derived from it never contact those of the connective tissue stroma. As with epithelia, they are always separated from connective tissue by a basement membrane. J. Morphol., 2007. © 2007 Wiley-Liss, Inc. [source] Effect of Mucuna urens (horse eye bean) on the gonads of male guinea-pigsPHYTOTHERAPY RESEARCH, Issue 2 2001Paul Udoh Abstract The effect of Mucuna urens (seeds) on the gonads and sex accessory glands of male guinea-pigs was investigated. Sexually mature guinea-pigs of proven fertility were administered orally with 70,mg/kg and 140,mg/kg body weight of crude extract daily for 8 weeks respectively. Phytochemical screening of the seeds revealed the presence of alkaloids. No death or weight loss were observed during the duration of treatment. No pregnancy occurred in females mated with the treated males. Histological observations at high dose (140,mg/kg) showed complete degeneration of sperm in the testicular tubules. In some tubules, the acrosomal cap of the sperm cells was separated from the nuclei which underwent colour changes. In some tubules only the tails were left in the lumen. The spermatids, primary and secondary spermatocytes showed pycnosis while the morphology of spermatogonia and germinal epithelium appeared normal. Some epididymides were devoid of sperm while others contained degenerated spermatozoa and cell debris. In the prostate gland there was collapse of the villi and reduction of secretion in both the prostate and seminal vesicles. At low doses (70,mg/kg), there was spermatogenic arrest at spermatid stage. These observations have shown that M. urens is a potential male antifertility agent. Copyright © 2001 John Wiley & Sons, Ltd. [source] | ||||||||||