Comparisons of in vivo BrdU labeling methods and spontaneous sister chromatid exchange frequencies in regenerating murine liver and bone marrow cells

Conner, Mary K.; Boggs, Sallie S.; Turner, John T.

doi:10.1007/bf00327165

Cited by 37 publications

(6 citation statements)

References 21 publications

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“…Ceils were then incubated in 0.075 M KC1 for 10 min at 37~ and fixed in 3:1 methanol to glacial acetic acid with at least three fixative changes. The cell suspension was dropped onto coded slides, which were then processed by the fluorescence plus Giemsa technique (Conner et al 1978) for R banding.…”

Section: Methodsmentioning

confidence: 99%

X chromosome imprinting in fragile�syndrome

Wenger

Steele

1990

Hum Genet

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Laird et al. (1987) hypothesized that there are at least four cis-acting alleles or 'chromosome states' at Xq27 that increasingly delay replication at this chromosomal area resulting in its increasing fragility in vitro. When on the inactive X chromosome, the proposed third ('mutated') allele can permanently block reactivation of its cis Xq27 area as the chromosome passes through female meiosis. Males and some females who inherit such an 'imprinted' fragile X chromosome (the fourth proposed allele) will be clinically affected due to impaired transcription of genes in the 'imprinted' Xq27 area. To test this hypothesis, late replication reverse banding patterns at Xq27 were evaluated in cultured lymphoblastoid cell lines from 25 subjects. Our data suggest that DNA replication of the presumed 'imprinted' Xq27 region in affected fragile X patients is indeed later relative to Xq27 on the active X chromosome in other subjects. These results support in part Laird's hypothesis of chromosomal imprinting in fragile X syndrome.

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Section: Methodsmentioning

confidence: 99%

X chromosome imprinting in fragile�syndrome

Wenger

Steele

1990

Hum Genet

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“…We investigated the self-renewal potential of the most atrophic p53 knockout rats in this study by analyzing the BrdU labeling rate of SSCs after a long-term BrdC exposure. Upon its uptake into cells, BrdC is de-aminated to form BrdU, which is then incorporated during S-phase DNA replication and can be used to label actively proliferating cells (Conner et al 1978). In a previous study of rats exposed to 2,5-hexanedione to deplete the germ cell population, the proliferative index of SSCs was found to be approximately 0.4 after 13 days of BrdC exposure (Allard et al 1995).…”

Section: Discussionmentioning

confidence: 99%

Spontaneous testicular atrophy occurs despite normal spermatogonial proliferation in a Tp53 knockout rat

et al. 2017

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The tumor suppressor protein p53 (TP53) has many functions in cell cycle regulation, apoptosis, and DNA damage repair, and is also involved in spermatogenesis in the mouse. To evaluate the role of p53 in spermatogenesis in the rat, we characterized testis biology in adult males of a novel p53 knockout rat (SD-Tp53tm1sage). p53 knockout rats exhibited variable levels of testicular atrophy, including significantly decreased testis weights, atrophic seminiferous tubules, decreased seminiferous tubule diameter, and elevated spermatocyte TUNEL labeling rates, indicating a dysfunction in spermatogenesis. Phosphorylated histone H2AX protein levels and distribution were similar in the non-atrophic seminiferous tubules of both genotypes, showing evidence of pre-synaptic DNA double-strand breaks in leptotene and zygotene spermatocytes, preceding cell death in p53 knockout rat testes. Quantification of the spermatogonial stem cell (SSC) proliferation rate with bromodeoxyuridine (BrdU) labeling, in addition to staining with the undifferentiated type A spermatogonial marker GDNF family receptor alpha-1 (GFRA1), indicated that the undifferentiated spermatogonial population was normal in p53 knockout rats. Following exposure to 0.5 or 5 Gy X-ray, p53 knockout rats exhibited no germ cell apoptotic response beyond their un-irradiated phenotype, while germ cell death in wild-type rat testes was elevated to a level similar to the unexposed p53 knockout rats. This study indicates that seminiferous tubule atrophy occurs following spontaneous, elevated levels of spermatocyte death in the p53 knockout rat. This phenomenon is variable across individual rats. These results indicate a critical role for p53 in rat germ cell survival and spermatogenesis.

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“…All slides were stained by a modification of the fluorescence plus Giemsa (FPG) method (9). Slides were coded and scored blindly.…”

Section: Evaluation Of Slidesmentioning

confidence: 99%

Evaluation of sister chromatid exchange and cytotoxicity in murine tissues in vivo and lymphocytes in vitro following methyl isocyanate exposure.

Conner¹,

Rubinson²,

Ferguson³

et al. 1987

Environ Health Perspect

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The purpose of this study was to assess sister chromatid exchange (SCE) levels and cell cycle kinetics in various murine tissues following MIC exposure. Following exposure of mice to MIC, these parameters were measured in bone marrow and alveolar macrophages labeled with BrdUrd in vivo and in peripheral blood and spleen lymphocytes cultured in the presence of BrdUrd in vitro. Target concentrations of MIC were 2, 15, and 30 ppm (3 hr).Neither elevated SCE frequencies nor inhibition of cell cycling were evident in lipopolysaccharide (LPS)-or concanavalin A (ConA)-stimulated spleen lymphocytes, or in LPS-stimulated peripheral blood lymphocyte (PBL) cultures from mice exposed for 3 hr to MIC concentrations as high as 30.5 ppm. Inhibition of cell cycling and poor culture success rates were apparent in ConA-stimulated PBLs following MIC exposures as low as 2.3 ± 0.4 ppm for 3 hr.At the lowest MIC dose employed, the cycling characteristics of bone marrow and alveolar macrophages were not altered, and SCE frequencies were at control levels. However, severe cell cycle inhibition was observed in these tissues at MIC concentrations of 15 ppm or greater. A marker of cytotoxicity at this dose was a high frequency (approximately 33-90%) of occurrence of first division cells containing a latereplicating Y chromosome.Despite its apparent cellular toxicity, MIC is not genotoxic as measured by SCE analysis in the tissues examined in this study.

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Comparisons of in vivo BrdU labeling methods and spontaneous sister chromatid exchange frequencies in regenerating murine liver and bone marrow cells

Cited by 37 publications

References 21 publications

X chromosome imprinting in fragile�syndrome

X chromosome imprinting in fragile�syndrome

Spontaneous testicular atrophy occurs despite normal spermatogonial proliferation in a Tp53 knockout rat

Evaluation of sister chromatid exchange and cytotoxicity in murine tissues in vivo and lymphocytes in vitro following methyl isocyanate exposure.

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