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  • 1
    Electronic Resource
    Electronic Resource
    Effects of static magnetic field on specific adenosine-5′-triphosphatase activities and bioelectrical and biomechanical properties in the rat diaphragm muscle (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 147-151 
    Details
    ISSN: 0197-8462
    Keywords: magnetic field ; ATPase ; resting membrane potential ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: In this study, we aimed to clarify the effects of chronically applied static magnetic field (200 Gauss) on specific ATPase activities and bioelectrical and biomechanical responses in the isolated rat diaphragm muscle. The mean activities of Na+-K+ ATPase and Ca2+ ATPase determined from the diaphragm homogenates were significantly higher in the magnetic field exposed group (n = 20), but that of Mg2+ ATPase was nonsignificantly lower compared to the control group (n = 13). Resting membrane potential, amplitude of muscle action potential, and overshoot values (mean ± SE) in the control group were found to be -76.5 ± 0.6, 100 ± 0.8, and 23.5 ± 0.6 mV, respectively; these values were determined to be -72.8 ± 0.4, 90.3 ± 0.5, and 17.2 ± 0.4 mV in the magnetic field-exposed group, respectively. The latency was determined to increase in the experimental group, and all the above-mentioned bioelectrical differences between the groups were significant statistically. Force of muscle twitch was found to decrease significantly in the magnetic field-exposed group, and this finding was attributed to the augmenting effect of magnetic field on Ca2+ ATPase activity. These results suggest that magnetic field exposure changes specific ATPase activities and, thence, bioelectrical and biomechanical properties in the rat diaphragm muscle. © 1995 Wiley-Liss, Inc.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bem.2250160302
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  • 2
    Electronic Resource
    Electronic Resource
    Introduction: Genes and development symposium: The era of transcription factors and gene knockouts (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 182-183 
    Details
    ISSN: 1040-452X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390210
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  • 3
    Electronic Resource
    Electronic Resource
    Pdha-2: A model for studying transcriptional regulation in early spermatocytes (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 194-199 
    Details
    ISSN: 1040-452X
    Keywords: Pdha-2 Promoter ; Spermatogenesis ; Transcription factors ; MEP-BF ; Mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Precise temporal and tissue-specific expression of genes during spermatocyte differentiation is crucial for the formation of functional spermatozoa. However, the mechanisms that regulate gene expression during spermatogenesis are poorly understood. One testisspecific gene, Pdha-2, is beginning to emerge as a potentially important model for the study of these events. This review focuses on our current understanding of the expression and regulation of Pdha-2 during spermatogenesis. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390212
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  • 4
    Electronic Resource
    Electronic Resource
    Role of interferons in the regulation of cell proliferation, differentiation, and development (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 226-232 
    Details
    ISSN: 1040-452X
    Keywords: Interferons ; Development ; Differentiation ; Proliferation ; Gene regulation ; Transcription factors ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: There now appears to be evidence to support the view that the type I IFNs are naturally produced negative regulators of growth that also modify cell differentiation. Consistent with this, it appears that the ability to produce and respond to IFN is suppressed in early embryonic development when cell proliferation and differentiation are essential. In the later stages of fetal development, IFN production is de-repressed, and cells show increased sensitivity to IFN, which may be important in regulating cell proliferation and/or differentiation processes or the interaction between fetal and maternal tissues. Interestingly, the IFN system can also be suppressed in disease states such as the development of tumours or in the establishment of a (chronic) viral infection. Therefore, understanding the developmental regulation of the IFN system may be important to understanding and controlling the IFN system in disease. More extensive studies of the developmental stage and tissue-specific expression of type I IFNs and their receptors are necessary, as well as more direct in vivo experiments to further elucidate the role of the IFN system in reproduction and development. © 1994 Wiley-Liss, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390216
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  • 5
    Electronic Resource
    Electronic Resource
    Regulation of gene expression by transcription factors Ets-1 and Ets-2 (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 39 (1994), S. 208-214 
    Details
    ISSN: 1040-452X
    Keywords: ETS ; Ets-1 ; Ets-2 ; DNA-binding domain ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The ETS family of transcription factors have a DNA-binding domain in common that binds a core GGA(A/T) DNA sequence. A large number of proteins have now been identified that contain an ETS DNA-binding domain (see review by Wasylyk et al., 1993). Ets-1 was first described as the cellular homolog of v-ets, which is translated as a 135-kDa gag-myb - ets fusion protein from the replication-deficient retrovirus E26 in chickens. Ets-2 was subsequently described as a closely related protein that contains the highly conserved ETS DNA-binding domain. This paper considers the manner by which the two closely related genes, Ets-1 and Ets-2, apparently play distinct roles in embryo development and in the immune system of adult mice. Although both Ets-1 and Ets-2 transform fibroblasts (Seth et al., 1989), the temporal and tissue-specific expression patterns suggest that these two proteins play distinct biological roles and consequently transactivate different downstream cellular target genes. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080390214
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of vitamin A deficiency on the inter - Sertoli cell tight junctions and on the germ cell population (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 20 (1992), S. 43-49 
    Details
    ISSN: 1059-910X
    Keywords: Vitamin A deficiency ; Blood-testis barrier ; Seminiferous epithelium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: When 20-day-old rats are placed on a vitamin A deficient diet (VAD) for a period of 10 weeks, the seminiferous tubules are found to contain only Sertoli cells, a few residual A0, A1 spermatogonia, and preleptotene spermatocytes (PL). The type A1 spermatogonia and PL spermatocytes are arrested in their G2 phase. In VAD rats type A2-A4, intermediate (In) and B spermatogonia and all types of spermatocytes (except PL spermatocytes) and spermatids are eliminated from the seminiferous tubules. Two questions were raised in this investigation: (1) Is there, in VAD rats, any correlation between a breakdown of the blood-testis barrier (e.g., Sertoli cell tight junctions) and germ cell loss? (2) Is the disappearance of most germinal cells due to their degeneration during spermatogenesis or to a maturation depletion process resulting from an arrest of spermatogenesis at the spermatogonial stage? To investigate these questions four groups of male Sprague-Dawley rats (20-days old) were fed a VAD diet for 7 to 12 weeks. The testes were fixed by perfusion with 2.5% glutaraldehyde in 0.1 M sodium cacodylate containing 2% lanthanum nitrate, an electron opaque tracer used to test the patency of Sertoli cell tight junctions. The lanthanum permeated the intercellular space of the basal compartment but was arrested by normal inter - Sertoli cell tight junctions. The seminiferous epithelium showed numerous degenerating germ cells, some being internalized by Sertoli cells as membrane-bound phagosomes. Thus, these results indicate firstly that inter - Sertoli cell tight junctions remain intact during vitamin A deficiency, and secondly that in a first phase nonviable germinal cells degenerate during spermatogenesis and their residues are actively phagocytosed by Sertoli cells followed by a second phase where the regressed state of the seminiferous epithelium is maintained by a maturation depletion condition resulting from an arrest of spermatogonial proliferation and differentation.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070200106
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  • 7
    Electronic Resource
    Electronic Resource
    Thermolability of mouse oocytes is due to the lack of expression and/or inducibility of Hsp70 (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 1-8 
    Details
    ISSN: 1040-452X
    Keywords: Heat shock proteins ; Thermotolerance ; Temperature sensitivity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Eukaryotic and prokaryotic cells have been shown to respond to physical and chemical stress by the induction of proteins called heat shock proteins. Heat shock protein 70 (Hsp70), is the most ubiquitous of these proteins. Although heat shock proteins are generally thought to protect cells from physiologically stressful stimuli, it cannot be assumed that this is so, because several cases exist in which thermotolerance is acquired without the production of heat shock proteins, and in several other cases the hyperproduction of these heat shock proteins does not produce thermotolerance. In this study we show that unfertilized mouse oocytes are sensitive to elevated temperatures, and that the synthesis of Hsp70 cannot be induced in these oocytes. Furthermore, our data demonstrate that the expression of Hsp70 in mouse oocytes is sufficient for the acquisition of thermotolerance. Mouse oocytes were injected with mRNA for Hsp70, and the viability of these oocytes was determined after heating. The number of viable oocytes was significantly higher in the group injected with Hsp70 mRNA and then heated compared with oocytes injected with Hsp70 antisense mRNA and sham-injected controls treated in an identical manner. No significant differences in the number of viable oocytes were found between the group that had been injected with Hsp70 mRNA, heated, and then allowed to recover for 3 hr and the group maintained at 37°C throughout. This study demonstrates that the injection of Hsp70 mRNA into unfertilized mouse oocytes significantly enhances their thermotolerance, indicating that the thermolability of mouse oocytes is due to the lack of expression of Hsp70. This study provides direct evidence for the role of Hsp70 in the enhancement of thermotolerance of mammalian cells.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080280102
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  • 8
    Electronic Resource
    Electronic Resource
    Preimplantation embryo biopsy: Detection of trisomy in a single cell biopsied from a four-cell mouse embryo (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 29 (1991), S. 16-21 
    Details
    ISSN: 1040-452X
    Keywords: Metaphase spreads ; Blastomeres ; Karyotyping ; Down syndrome ; Micromanipulation ; Mouse trysomy 16 ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This paper describes an efficient technique for the production of metaphase spreads from single blastomeres biopsied from four-cell preimplantation mouse embryos. The karyotype obtained by chromosomal analysis of single biopsied cells is shown to be fully predictive of subsequent fetal karyotype. The data in this study also demonstrate that the entire process of embryo biopsy and karyotypic analysis of biopsied blastomeres does not adversely affect the ability of biopsied embryos to form fetuses after transfer into pseudopregnant recipients. This study has potential clinical relevance in that it demonstrates that chromosomally defective embryos can be accurately identified before implantation. In addition, the techniques developed in this study may facilitate more efficient procedures for the genesis of animal models for human disorders such as Down syndrome and Alzheimers disease.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080290104
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