Squash Preparation Studies of Germ Cells in Human Fetal Testes

Sun, Eric L.; Gondos, Bernard

doi:10.1002/j.1939-4640.1984.tb00798.x

Cited by 8 publications

(4 citation statements)

References 14 publications

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“…Meiotic activity does not begin until this time. Fetal and neonatal preleptotene activity has been observed in the human (Devictor et al, 1979;Sun and Gondos, 1984) and rabbit testis (Gondos and Byskov, 1981), but it has been suggested that this may represent a postmitotic phenomenon (Hilscher and Hilscher, 1981). Presperrnatogenic human male germ cells do not complete meiosis (Devictor et al, 1979) and presumably degenerate.…”

mentioning

confidence: 99%

Morphometric study of the prepubertal rabbit testis: Germ cell numbers and seminiferous tubule dimensions

1991

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Testes from rabbits aged 1-9 weeks were examined by light microscopy. Changes in seminiferous tubule dimensions, testicular volume, and volume fraction of tubules were assessed. Germ cells and Sertoli cells were counted in round tubular cross sections and total germ cell number in each testis was estimated. Mitotic, meiotic, and degenerative activities of germ cells as well as their basal or central positions within tubules were quantified. A marked, steady increase in testis volume and in tubular length and volume occurred over the prepubertal period; but diameter underwent no significant increase and in fact decreased until week 4. Overall, tubules lengthened 40-fold and testis volume increased 25-fold; the percentage volume of the testis occupied by tubules rose from one-third neonatally to three-fifths at the onset of spermatogenesis. The ratio of germ cells to total tubular (germ and Sertoli) cells was lowest at 3 weeks. However, the total number of germ cells increased little until 3 weeks, after which it rose at a sharp rate commensurate with testis volume. Percentage of germ cells in mitosis peaked sharply at 3 weeks, dropped in subsequent weeks, and then rose at 7 weeks at the initiation of spermatogenesis. Importantly, the surge in mitosis at 3 weeks was followed by a redistribution of germ cells to a predominantly basal location from 3 to 7 weeks. Meiotic activity was sparse at 7 weeks and became abundant by 9 weeks. Germ cell degeneration remained relatively constant during weeks 1 through 6, with an increase at 7 weeks.

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confidence: 99%

Morphometric study of the prepubertal rabbit testis: Germ cell numbers and seminiferous tubule dimensions

1991

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“…From there, they proceed to migrate through the hindgut during the fourth week and dorsal mesentery in the fifth week to reach the genital ridge. [70][71][72] By the end of the fifth week or early in the sixth week, ∼1000 PGCs begin to actively migrate from the dorsal mesentery to the genital ridge. [73][74][75] At this time, in the female, premeiotic PGCs begin extensive mitotic expansion until they arrest in prophase of meiosis I beginning around week 10 in gestation.…”

Section: Embryonic Germ Cellsmentioning

confidence: 99%

Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations

Swelstad

Kerr

2009

SCCAA

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Pluripotent stem cells have been derived from various embryonic, fetal and adult sources. Embryonic stem cells (ESCs) and parthenogenic ESCs (pESCs) are derived from the embryo proper while embryonic germ cells (EGCs), embryonal carcinoma cells (ECCs), and germ-line stem cells (GSC) are produced from germ cells. ECCs were the first pluripotent stem cell lines established from adult testicular tumors while EGCs are generated in vitro from primordial germ cells (PGCs) isolated in late embryonic development. More recently, studies have also demonstrated the ability to produce GSCs from adult germ cells, known as spermatogonial stem cells. Unlike ECCs, the source of GSCs are normal, non-cancerous adult tissue. The study of these unique cell lines has provided information that has led to the ability to reprogram somatic cells into an ESC-like state. These cells, called induced pluripotent stem cells (iPSCs), have been derived from a number of human fetal and adult origins. With the promises pluripotent stem cells bring to cell-based therapies there remain several considerations that need to be carefully studied prior to their clinical use. Many of these issues involve understanding key factors regulating their generation, including those which define pluripotency. In this regard, the following article discusses critical aspects of pluripotent stem cell derivation and current issues about their therapeutic potential.

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“…33,37,38 Alkaline phosphatase activity is lost just after germ cells enter meiosis. 32,39,40 EGC DERIVATION…”

Section: Human Pgc Developmentmentioning

confidence: 99%

Embryonic Germ Cells: When Germ Cells Become Stem Cells

Kerr

Gearhart²,

Elliott

et al. 2006

Semin Reprod Med

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Embryonic germ cells (EGCs) are pluripotent stem cells derived from primordial germ cells (PGCs). PGCs are progenitors of adult gametes, which diverge from the somatic lineage between late embryonic to early fetal development. First derived in the mouse, EGCs have also been derived from human, chicken, and pig. As pluripotent stem cells, EGCs demonstrate long-term self-renewal via clonal expansion in an undifferentiated state, and differentiate in vitro to form embryoid bodies containing cells that represent all three germ layers as well as mixed cell populations of less differentiated progenitors and precursors. This is also demonstrated in vivo by their formation into experimentally induced teratocarcinomas following transplantation. Furthermore, mice, pig, and chicken EGCs have also been shown to contribute to experimentally produced chimeric animals, including germline transmission. Importantly, EGCs demonstrate normal and stable karyotypes as well as normal patterns of genomic imprinting, including X-inactivation. Transplantation studies have begun in a variety of models in hopes of defining their potential use to treat a wide variety of human conditions, including diabetes and urological and neurological disorders.

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Squash Preparation Studies of Germ Cells in Human Fetal Testes

Cited by 8 publications

References 14 publications

Morphometric study of the prepubertal rabbit testis: Germ cell numbers and seminiferous tubule dimensions

Morphometric study of the prepubertal rabbit testis: Germ cell numbers and seminiferous tubule dimensions

Current protocols in the generation of pluripotent stem cells: theoretical, methodological and clinical considerations

Embryonic Germ Cells: When Germ Cells Become Stem Cells

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