Where results make sense

About us   |   Why use us?   |   Reviews   |   PR   |   Contact us

[No title] The A-1 cell becomes dedicated to spermatocytogenesis and the A-0 cell is kept in reserve for future divisions. Endogenous damage to the the genetic material (eg., base deamination, depurination, methylation, oxidative insult) is inevitable in proliferative cells - a battery of repair mechanisms assure that the DNA fidelity of gametes is sustained. Spermatocytogenesis is completely arrested at the primary spermatocyte stage in hypophysectomized animals; this step is restored by testosterone. www.uwyo.edu /wjm/repro/spermat.htm   (1768 words)

rep5 Spermatocytogenesis-This is a proliferative phase, in which spermatogonia (germ cells) multiply by mitotic divisions in order to produce primary spermatocytes. After the mitotic divisions, primary spermatocytes undergo meiosis to form secondary spermatocytes, which undergo a second meiosis to form spermatids. Spermatocytogenesis ends with the formation of round spermatids. www.vet.purdue.edu /bms/nour/production/Physiology/reproductive/rep5.htm   (367 words)

SSR 2002   (Site not responding. Last check: 2007-10-10) In prepubertal animals a distinct nuclear staining of the PR was observed in the prespermatogonia close to the basal lamina but not in the luminal ones. Expression of the PR could be demonstrated at all ages, sequenzing of the amplicons confirmed to the porcine PR. These data suggest that testicular P seems to act as a paracrine factor involved in the early phase of spermatocytogenesis, the role of the testicular E needs further investigations. abstracts.co.allenpress.com /pweb/ssr2002/document?ID=3521   (328 words)

bc_martini_eap_3| Cell Structure and Function|Embryology Atlas The first stage of spermatogenesis is spermatocytogenesis in which the spermatogonia develop into spermatocytes and then into spermatids. The second stage in the formation of spermatozoa is spermiogenesis (spermateliosis), in which the spermatids transform into spermatozoa. Spermatocytogenesis involves developmental changes of the nucleus, but spermiogenesis chiefly involves the cytoplasm. wps.aw.com /bc_martini_eap_3/0,7016,453746-,00.html   (437 words)

Spermatogenesis - Wikipedia, the free encyclopedia Spermatogenesis is the process by which stem cells develop into mature spermatozoa. There are three phases: Spermatocytogenesis (Mitosis), Meiosis, and Spermiogenesis. Stem cells (Type A spermatogonia; singular = spermatogonium) divide mitotically to replace themselves and to produce cells that begin differentiation (Type B spermatogonia). en.wikipedia.org /wiki/Spermatogenesis   (655 words)

SSR 2002   (Site not responding. Last check: 2007-10-10) Timing of first cleavage was evaluated as faster cleaving embryos are more likely to develop to the morula/blastocyst stage. The ratio of cleavage at 32/48 hr was decreased (p<0.05) for collections (days ASI) with sperm undergoing epididymal transit (day 2), spermiogenesis (day 14, 23), meiosis (days 30, 33, 35, 37, 47) and spermatocytogenesis (days 49, 61 and 66) at the time of insulation. The number of nuclei in embryos after 135 hr of culture were reduced for collections (days ASI) from 19±1 nuclei (day 0) to 13±2 (day 14) and 16±2 (day 26). abstracts.co.allenpress.com /pweb/ssr2002/document?ID=4160   (289 words)

Male Reproduction 4 Spermatogenesis There are three phases: (1) Spermatocytogenesis (Mitosis), (2) Meiosis, and (3) Spermiogenesis. Spermatocytogenesis (also called Mitosis): Stem cells (Type A spermatogonia; singular = spermatogonium) divide mitotically to replace themselves and to produce cells that begin differentiation (Type B spermatogonia). Spermatogonia have spherical or oval nuclei, and rest on the basement membrane. www.cvmalumni.okstate.edu /instruction/mm_curr/histology/MR/HiMRP4.htm   (807 words)

Efficiency of spermatogenesis.   (Site not responding. Last check: 2007-10-10) Spermatocytegenesis involves mitotic cell division to increase the yield of spermatogenesis and to produce stem cells and primary spermatocytes. Spermatogenesis and germ cell degeneration can be quantified from numbers of germ cells in various steps of development throughout spermatogenesis, and quantitative measures are related to number of spermatozoa in the ejaculate. Efficiency of spermatogenesis is related to the amount of germ cell degeneration, pubertal development, season of the year, and aging of humans and animals. www.arclab.org /medlineupdates/abstract_8563040.html   (354 words)

Quantification of human spermatogenesis: germ cell degeneration during spermatocytogenesis and meiosis in testes from ... Quantification of human spermatogenesis: germ cell degeneration during spermatocytogenesis and meiosis in testes from younger and older adult men. Germ cell degeneration during spermatocytogenesis and meiosis was investigated to explain the age-related decline in daily sperm production (DSP). Testes obtained within 15 h of death (largely due to trauma or heart failure) were perfused vascularly with glutaraldehyde. www.arclab.org /medlineupdates/abstract_3676417.html   (262 words)

spermatogenesis The purpose of this section is to examine the subcategories of spermatogenesis: spermatocytogenesis, meiosis and spermiogenesis. A description of the abbreviations for this section may be helpful to check if you can not figure out what something is labeled. Identify the Sertoli cells which regulate spermatogenesis and are often refered to as nurse cells. www.wisc.edu /ansci_repro/lab/lab8/spermatogenesis/spermatogenesis.html   (351 words)

Title page for ETD   (Site not responding. Last check: 2007-10-10) The normal developmental process of spermatocytogenesis is investigated as the first application. As the second application, the spermatocytogenesis model is then altered to demonstrate a modeling strategy for hormesis. The direct Lyapunov method for linear differential equations without delay is modified to establish delay-dependent stability conditions for delay differential equations with multiple delays. www.lib.ncsu.edu /etd/public/etd-222015201010013240/etd-title.html   (440 words)

Seasonal differences in equine spermatocytogenesis -- Johnson 44 (2): 284 -- Biology of Reproduction   (Site not responding. Last check: 2007-10-10) Seasonal differences in equine spermatocytogenesis -- Johnson 44 (2): 284 -- Biology of Reproduction Spermatocytogenesis plays a pivotal role in regulation of spermatogenesis; Copyright © 1991 by the Society for the Study of Reproduction. www.biolreprod.org /cgi/content/abstract/44/2/284   (350 words)

Exploring the Biological Contributions to Human Health: Usually any cell of a multicellular organism that will not contribute to the production of gametes, i.e., most cells of which an organism is made; not a germ cell. The process of formation of spermatozoa, including spermatocytogenesis and spermiogenesis. Relationship between the desired and undesired effecters) of a drug, that is, the benefit/risk ratio. newton.nap.edu /books/0309072816/html/239.html   (2013 words)

Newly Approved Drug Therapies (895): Myozyme (alglucosidase alfa), Genzyme Genzyme commits to submit the data from the third Segment I. reproductive/toxicology study in mice. If necessary, Genzyme commits to submit an additional protocol for the study of the effects of Myozyme on spermatocytogenesis and spermiogenesis in male rabbits. In any future protocols, animals should be treated for a minimum of 90 days. www.centerwatch.com /patient/drugs/dru895.html   (2037 words)

[No title]   (Site not responding. Last check: 2007-10-10) The cytoplasmic bridge formed between germ cells due to their incomplete division persists until the moment of release from the Sertoli cells. No, the answer is E. Spermatogenesis involves three processes 1) spermatocytogenesis, 2) meiosis, and 3) spermiogenesis. Meiosis provides the haploid number of chromosomes in the spermatid. www.kumc.edu /research/medicine/pharmacology/CAI/webCAI/anatomy/to19.wbc   (709 words)

handout 5 - testes and spermatogenesis Of the cells resulting from these mitotic divisions, some spermatogonia stay in the "resting" pool, while the remaining type A spermatogonia proliferate several times and undergo 1 to 5 stages of division and differentiation. After the last division, the resulting cells are termed primary spermatocytes and this ends spermatocytogenesis. The primary spermatocytes then undergo the first of the two division that constitute meiosis. www.wisc.edu /ansci_repro/lec/handouts/hd5.html   (1489 words)

Prolactin Induces Apoptosis in the Penultimate Spermatogonial Stage of the Testes in Japanese Red-Bellied Newt (Cynops ... causes the cessation of spermatocytogenesis from late autumn Newts were transferred from cold room to room temperature and kept time, spermatogonia proliferated and then active spermatocytogenesis occurred. endo.endojournals.org /cgi/content/full/141/6/2027   (3306 words)

Try your search on: Qwika (all wikis)

About us   |   Why use us?   |   Reviews   |   Press   |   Contact us   Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.