Results 201 to 210 of about 24,341 (244)

Regulation of the density of spermatogonia in the seminiferous epithelium of the Chinese hamster: I. Undifferentiated spermatogonia

The Anatomical Record, 1987
AbstractThe topographical arrangement of the clones of Asingle, Apaired, and Aaligned (As, Apr, and Aal) spermatogonia on the basement membrane of seminiferous tubules of the Chinese hamster was studied. It was found that at least some of these clones are not distributed at random as clones of similar cell number were often seen in clusters. Areas were
de rooij, D. G., Janssen, J. M.
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Renewal of spermatogonia in man

American Journal of Anatomy, 1966
AbstractThe spermatogonia of normal adult human testis were investigated in view of clarifying their mode of proliferation and renewal. Three main types of spermatogonia were identified: the dark type A spermatogonia (Ad) tentatively considered as the stem cells, the pale type A spermatogonia (Ap) and the type B spermatogonia (B), these being the more ...
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Regulation of the Differentiation of the Undifferentiated Spermatogonia

2000
In the seminiferous epithelium of adult nonprimate mammals, so-called A-single (As) spermatogonia are the stem cells of spermatogenesis (1–3). Upon division of the As spermatogonia, the daughter cells either migrate away from each other and become two new stem cells, or the cells stay together becoming A-paired (Apr) spermatogonia connected by an ...
de Rooij, D.G., Schrans-Stassen, B.H.G.J., van Pelt, A.M.M., Shuttlesworth, G.A., Meistrich, M.L., Okabe, M., Nishimune, Y.   +6 more
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Absence of spermatogonia in the Prader-Willi syndrome

European Journal of Pediatrics, 1977
Bilateral testicular biopsies in an 81/2 year old boy with the Prader-Willi syndrome showed total absence of spermatogonia. Similar findings in postpubertal cases (Wannarachue et al., 1975) suggest that testicular dysplasia is one of the reasons for hypogonadism in males with the Prader-Willi syndrome.
M L, Katcher, G J, Bargman, E F, Gilbert, J M, Opitz   +3 more
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Cytotoxicity of ethyl methanesulfonate in mice spermatogonia

Experientia, 1979
Enumeration of different types of spermatogonia, following a single i.p. administration of different doses of ethyl methanesulfonate in mice, showed a survival of A1-A4 and in spermatogonia is markedly reduced due to cell killing while the remaining types of spermatogonia were affected marginally.
D, Bhattacharjee, T K, Shetty, K, Sundaram   +2 more
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The Effect of Tritiated Thymidine on Mouse Spermatogonia

Radiation Research, 1959
is extremely complex. The theoretical prediction of the radiation effects of tritiated thymidine in vivo is particularly difficult. The concentration of tritiated thymidine into the nuclei of relatively few cells in the body and the selective intrachromosomal irradiation by short-range f-particles increase the likelihood of biologic effects from a ...
H A, JOHNSON, E P, CRONKITE
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Morphology of the reproductive system of the armadillo. The spermatogonia

Journal of Morphology, 1973
AbstractSpermatogonia of the nine‐banded armadillo, Dasypus novemcinctus mexicanus, were studied morphologically using light and electron microscopy and examined histochemically using light microscopy. Immature flat type spermatogonia have ovoid or irregular nuclei with loosely condensed chromatin.
F, Nagy, R H, Edmonds
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In Vitro Differentiation of Spermatogonia

2017
Presence of functional spermatogonial population secures continuing spermatogenesis, by repeated commencement of spermatogenic cycles from them. In vitro manipulation of spermatogonia, thus, can be divided into two aspects: proliferation of spermatogonia for their maintenance and initiation of their differentiation toward sperm formation.
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Mutagenesis in murine spermatogonia by mopp therapy

Reproductive Toxicology, 1987
Male mice were given mechlorethamine (2.0 mg/kg) followed immediately or 1, 2, 4, or 8 h later by procarbazine (100 mg/kg) and vincristine (0.67 mg/kg) in a protocol that stimulated the drugs and dosages used in a single cycle of clinical MOPP therapy.
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Gamma‐ray sensitivity of spermatogonia of the mouse

Journal of Experimental Zoology, 1957
Hybrid mule mice were given a range of doses from 5 to 100 r of Co gamma rays, killed 72 hours after irradiation, and all spermatogonia counted in 100 tubule cross sections per mouse. Young primary spermatocytes at stages VII and VIII in the cycle of the seminiferous epithelium also were counted.
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