(n.) A primitive seminal cell, occuring in masses in the seminal tubules. It divides into a mass (spermosphere) of small cells (spermoblast), which in turn give rise to spermatozoids.
Example Sentences:
(1) An Ap1 spermatogonium produces two Ap2 spermatogonia during Stage II of the cycle, Ap2 spermatogonia produce four type B spermatogonia during Stage VI of the cycle, and type B spermatogonia produce eight primary spermatocytes during Stage III of the cycle.
(2) These data suggest that the cell(s) of the seminiferous tubule involved in FSH regulation must be either the type A spermatogonium or the Sertoli cell.
(3) The relative amount of DNA in a somatic cell to that in a spermatogonium averaged 79.2%.
(4) Additionally it also inhibits the process of spermatogonium multiplication in the testis and of the progesterone multiplication in the ovary.
(5) The intermediate spermatogonium contins an ovoid nucleus characterized by one or two nuclei and heterochromatin scattered in the nuceoplasm.
(6) In the basal third of the Sertoli cell, membranous segments that faced a spermatogonium or a migrating spermatocyte displayed forming tight, gap, and adherens junctions.
(7) This finding was interpreted as the result of a single act of non-disjunction taking place in a spermatogonium.
(8) Testosterone bound to target cells initiates their division and decreases duration of spermatogonium mitosis block and delay in primary spermatocyte development increasing the number of germ cells.
(9) In some of the animals, a few isolated seminiferous tubules contained an occasional spermatogonium or primary spermatocyte.
(10) a single spermatogonium gives rise to 32 spermatozoa.
(11) The administration of exogenous testosterone was shown to stimulate DNA synthesis, inhibited by the effect of radiation, in spermatogonium populations of A1-4, intermediate, and B types, and in preleptotene primary spermatocytes; RNA synthesis was increased in the same populations of spermatogonia and pachytene primary spermatocytes.
(12) Each divides to produce a new Ad spermatogonium and a Ap1 spermatogonium during Stage IX of the cycle of the seminiferous epithelium.
(13) Repopulating spermatogenic colonies, found in the seminiferous epithelium after irradiation with fast-fission neutrons, were studied to determine the chance that a stem cell Asingle (As) spermatogonium would complete a self-renewing division (P).
(14) A preliminary report on the selective effect of Vinca rosea L. alkaloids on Type A4 rat spermatogonium is presented.
(15) The nucleus of the type "B" spermatogonium is more spherically shaped with a centrally placed nucleolus and heterochromatin associated with the nuclear envelope.
(16) The type "A" spermatogonium contains an oblong nucleus with one or two shallow infoldings of the nuclear membrane.
(17) Consequently, 32 spermatids can result from each division of an Ad spermatogonium.
(18) Various premeiotic and meiotic stages, from spermatogonium A and B to metaphase 1, were identified in the bull ejaculates.
(19) Pathological and electron microscopic examinations indicated that spermatogenic cells were damaged by MeHg especially spermatogonium and spermatocyte.
(20) Histological examination of rat testis, revealed that the spermatogenesis is arrested at spermatogonium stage in rats fed on protein free diet, and at primary and secondary spermatocyte stage in rats fed on normal but reduced diet.
Undifferentiated
Definition:
(a.) Not differentiated; specifically (Biol.), homogenous, or nearly so; -- said especially of young or embryonic tissues which have not yet undergone differentiation (see Differentiation, 3), that is, which show no visible separation into their different structural parts.
Example Sentences:
(1) The subcellular distribution of sialyltransferase and its product of action, sialic acid, was investigated in the undifferentiated cells of the rat intestinal crypts and compared with the pattern observed in the differentiated cells present in the surface epithelium.
(2) Macrophages, undifferentiated fibroblasts and highly differentiated fibroblasts can be observed.
(3) Carcinomas exhibiting atypical behavior are characteristically undifferentiated and aggressive.
(4) Because of its potential significance in human lung cancer, we investigated the expression of the CYP1A1 structural gene in 24 established human lung cancer cell lines including 15 non-small cell (eight adenocarcinomas, three large cell undifferentiated carcinomas, two bronchioloalveolar cell carcinomas, and two squamous cell carcinomas) and nine small cell lung carcinomas.
(5) All 51 undifferentiated NPCs contained significant numbers of EBV-genome copies per cell.
(6) Unfortunately, it does not contain a population of undifferentiated stem cells to supply the necessary healthy neurons.
(7) The anterior division can be further parcellated into dorsal, lateral, and ventral areas, and each of these areas, along with the posterior division, can be thought of as containing more-or-less discrete nuclei embedded within a relatively undifferentiated region.
(8) In undifferentiated glioblastomas, the reverse situation was observed, no SS receptors were found (0 of 14) but EGF receptors were present in a majority of tumors (8 of 14).
(9) The human epidermal growth factor receptor (hEGF-R) was introduced into murine P19 embryonal carcinoma (EC) cells, which do not express endogenous EGF-R. Undifferentiated stable P19 EC transfectants containing multiple copies of the hEGF-R complementary DNA were isolated.
(10) However, the tip cells are slow to differentiate, and hence immature fruiting bodies contain a small population of undifferentiated tip cells.
(11) We report on a patient with AL, which showed a very rapid switch from the lymphoblastic phenotype exhibited at presentation to a myelomonoblastic one, appeared at first relapse, and lastly progressed to an undifferentiated leukemia in the terminal phase.
(12) The pathologic diagnosis was rhabdomyosarcoma in 75% of cases, yolk sac tumor in 13% of cases, malignant mesenchymoma in two cases, clear cell carcinoma in two cases, and undifferentiated sarcoma in one case.
(13) Of 28 rats given 0.15 mg of 1,6-DNP, 21 (75%) developed squamous cell carcinomas, 2 (7%) developed undifferentiated carcinomas, and 2 (7%) had squamous metaplasias in the lung by 72 weeks.
(14) A case of large cell undifferentiated adenocarcinoma of the lung was complicated by an aggressive clinical course and documented placental metastases.
(15) In anurans, the oculomotor neurons receive a variety of visual, somatic, and vestibular afferents and appear relatively undifferentiated, whereas the nInt appears more developed.
(16) In previous specimens, solid undifferentiated carcinoma was absent or was a minor pattern.
(17) There was a nonsignificant trend toward higher MHPG levels in paranoid schizophrenic patients in comparison with patients who had undifferentiated schizophrenia.
(18) The process from the first undifferentiated stage to the second predifferentiated stage with well-developed ER and Golgi apparatus requires both collagen gels and hormones.
(19) The possibility of preventing or influencing the course of these diseases by vaccination has been advocated for a number of years [Epstein, 1976], especially in the case of undifferentiated nasopharyngeal carcinoma, which is the most common tumour of men in southern China and is prevalent in other specific regions; it therefore represents a major world cancer problem [Shanmugaratnam, 1971].
(20) Ultrastructurally, the tumor cells were composed principally of undifferentiated mesenchymal cells, and contained prominent pools of glycogen in the cytoplasm.