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  • 1
    Digitale Medien
    Digitale Medien
    Subzonal microinjection of mouse spermatozoa: Insufficient sperm motility might induce phagocytosis (1991)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 28 (1991), S. 47-54 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Spermatozoa ; Slight motility ; Microinjection ; In vitro fertilization ; Zona pellucida ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Acrosome-reacted CB6F1 mouse spermatozoa with slight flagellar motility were microinjected under the zona pellucida of CB6F1 mouse oocytes. Electron microscopy revealed the presence of swollen and decondensed sperm heads in the oocyte cytoplasm. Sixty-one percent of the microinjected oocytes reached a morphologically apparent two-cell stage, but chromosomal analysis demonstrated only haploid chromosomal complements in all cases. The exposure of microinjected oocytes to suspensions of spermatozoa of mice homozygous for a 2,4 reciprocal translocation resulted in normal fertilization and embryonic development with a maternally as well as a paternally derived haploid genome. Identical results were obtained with oocytes microinjected with medium and subjected to in vitro fertilization thereafter. Thus it can be suggested that the microinjected spermatozoa with insufficient flagellar motility are incorporated into the oocyte cytoplasm by phagocytosis. These spermatozoa do not induce a polyspermy block but induce the oocyte to parthenogenetic development.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080280108
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  • 2
    Digitale Medien
    Digitale Medien
    Germ cell-specific expression of a proacrosin-cat fusion gene in transgenic mouse testis (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 31 (1992), S. 241-248 
    Details
    ISSN: 1040-452X
    Schlagwort(e): Proacrosin gene regulation ; cis-Regulatory elements ; CAT reporter gene ; Transgenic mice ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Acrosin is a serine proteinase located in a zymogen form, proacrosin in the acrosome of the sperm. It is released as a consequence of the acrosome reaction and is believed to be the most important enzyme in the fertilization process. In the mouse, the proacrosin gene is transcribed premeiotically in spermatocytes, but protein biosynthesis starts in haploid spermatids and is restricted to the emerging acrosome. Four lines of transgenic mice harboring 2.3 kb of 5′ untranslated region of the rat proacrosin gene fused to the CAT-reporter gene were generated by microinjection of fertilized eggs. The chimeric gene was found to be present in 10-100 copies per genome in the different strains. The 5′ untranslated region of rat proacrosin gene could properly direct CAT-gene expression to spermatocytes and CAT-mRNA translation to round spermatids as it is known for mouse proacrosin gene. However, CAT protein is not restricted to the acrosome; rather, it is distributed in the spermatid cytoplasm. This could be due to the lack of DNA sequences for a hydrophobic leader peptide that have been found in all mammalian proacrosins studied until now but that was not present in transgene. It can be concluded from our results that cis-acting sequences required for tissue specific proacrosin expression reside on a 2.3-kb restriction fragment and are conserved in the proacrosin genes of mouse and rat.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/mrd.1080310403
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  • 3
    Digitale Medien
    Digitale Medien
    Ocular lens gap junctions: Protein expression, assembly, and structure-function analysis (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 31 (1995), S. 347-356 
    Details
    ISSN: 1059-910X
    Schlagwort(e): Cell-to-cell channels ; Connexins ; Membranes ; Intercellular communication ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Allgemeine Naturwissenschaft
    Notizen: Recent advances in understanding lens fiber gap junction formation are reviewed. These include studies of junctional protein expression in the embryonic lens, and of age related changes affecting gap junction structure and composition in the adult lens. An in vitro assembly system based on detergent solubilized pore complexes and endogenous lipids has been developed to provide information on the molecular interactions involved in gap junction formation and to provide material for structure analysis. Important information on the electrical properties of lens gap junction channels is obtained using electrophysiological techniques including planar lipid bilayer analysis and patch clamping. © 1995 Wiley-Liss, Inc.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jemt.1070310504
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  • 4
    Digitale Medien
    Digitale Medien
    Autonomic innervation in rabbit salivary glandsThis work was in part supported by: PHS-5-TOIGM00643, PHS-DE-02201 and PHS-DE-2636, and submitted in partial fulfillment of the requirements for the degree of Master of Science in Anatomy in the Graduate College, University of Illinois at the Medical Center, Chicago. (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 167 (1970), S. 87-105 
    Details
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Autonomic innervation of rabbit salivary glands was demonstrated by modifications of the methods of Falck for catecholamines and Koelle for the localization of cholinesterase activity. To avoid and diminish artifacts, tissues were rapidly frozen, cut in a cryostat, and freeze-dried under vacuum. Catecholamine fluorescence and cholinesterase activity were found in the serous parotid and the mainly mucous submandibular gland, strongly indicating that both glands are innervated by sympathetic and parasympathetic fibers. In the parotid gland, the sympathetic ground plexus apparently forms a denser network than that seen in the submandibular gland. Catecholamine fluorescence, indicating sympathetic nerves, is found to be closely related to most acini, blood vessels of both glands, and some ducts of the submandibular gland. Cholinesterase activity, signaling the presence of parasympathetic fibers, was observed around many acini, ducts, and some blood vessels of both glands. A theory is presented that the autonomic innervation of salivary glands influences the state of intracellular colloids, water, and electrolytes during secretion.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/ar.1091670109
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  • 5
    Digitale Medien
    Digitale Medien
    Changes in cells, matrix and water of calcifying turkey leg tendonsThis work was supported by grants from the United States Public Health Service, DE 01849, General Research Support Grant and Career Development Award 1-K3-DE-32,729-01 (E. Z.) and from the Graduate College Research Board. (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 120 (1967), S. 489-525 
    Details
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Alterations in morphology and composition of ossifying turkey leg tendons were followed using biophysical and histochemical procedures in combination with improved methods of tissue preparation. The principal biophysical changes accompanying calcification were loss of water, increase in shrinkage temperature, shifts in form birefringence curves and increased resistance to the disrupting effects of potassium iodide. Fibroblasts of the tendon were modified to cuboidal cells; at the same time, intracellular lipid increased and presumptive secretion of glycoproteins and lipids into the contiguous matrix was observed. As the bony tendon matured, osteocytes appeared and the stainability of the matrix with the periodic acid-Schiff reagent and dinitrofluorobenzene was markedly diminished. The matrix changes were interpreted as representing increased cross-linking of a negatively charged biological polyelectrolyte. Concurrently, diminished binding of calcium, the formation of hydrophobic lipid-containing phases and the lowering of dielectric constant favor the precipitation of bone salts. During calcification, barriers to diffusion, including low vascularity, tend to create a closed, or partially closed, system in the tissue. Then, the mineral phases form with minimal transfer of electrolytes to the circulation. According to the phase rule, the formation of insoluble bone salts stabilizes the heterogeneous biological structure.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/aja.1001200306
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  • 6
    Digitale Medien
    Digitale Medien
    Reactive dyes as vital indicators of bone growthThis work was supported by USPHS Grants DE-01468, DE-02636 and DE-01849. (1969)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 126 (1969), S. 373-391 
    Details
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Certain reactive dyes of the procion M and remazol group were effective for vital staining of growing bones. These compounds appear to form covalent bonds with the protein matrices and are preserved in situ after decalcification. Dye concentrations in sera of animals receiving one injection were followed. There was a precipitous drop in optical density in the first 24 hours; the remainder of the dye was largely cleared from the serum in 11-21 days. Dye concentrations and staining of bone were correlated. The width of the stained bone appeared to be related to rate of growth and disappearance of dye from the blood. On electrophoresis, the dyes moved with the albumin fraction. Dialysis and electrophoresis experiments favored the conclusion that they form covalent bonds with the protein. Growth of the rabbit mandible at 5-13 weeks, was studied by microscopy in decalcified sections. Using multicolored dyes, the sites of growth were marked in known sequence and sites of resorption were identified by interruption of stained zones. Principles of growth and remodelling advanced by Enlow were confirmed and the growth pattern of the rabbit mandible was elucidated.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/aja.1001260309
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  • 7
    Digitale Medien
    Digitale Medien
    Histochemical investigation of fiber type ratios with the myofibrillar ATP-ASE reaction in normal and denervated skeletal muscles of guinea pigThis study was supported in part by the Muscular Dystrophy Association of Canada. (1968)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 122 (1968), S. 145-155 
    Details
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The myofibrillar ATPase histochemical reaction was utilized to determine the proportion of the two basic histochemical fiber types in three “mixed” skeletal muscles of guinea pig after denervation. In five normal control animals, there was no significant difference in the proportion of fiber types on the two sides. In 12 experimental animals from 6-27 weeks after right sciatic neurectomy, the intensity of the myosin ATPase activity was not appreciably altered in the denervated muscle fibers but the type II (dark) fibers underwent preferential atrophy. The fiber type ratio between denervated and control sides in the experimental animals was not significantly different from the same values in the normal control animals. This allowed the conclusion that, up to 27 weeks after denervation, the histochemical typing of a fiber by the myofibrillar ATPase reaction probably reflects the original fiber type. This reaction is the preferred method for fiber typing in denervated guinea pig muscle, especially since most other histochemical reactions show markedly reduced activity of muscle enzymes after denervation and are unsuitable for fiber typing. The soleus, which normally contains only type I fibers, showed numerous type II fibers at 27 weeks after denervation and this was interpreted as a dedifferentiating process.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/aja.1001220109
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  • 8
    Digitale Medien
    Digitale Medien
    Collagen distribution in the rat demonstrated by a specific anti-collagen antiserumThe work was supported in part by grants DE 02636-01 to -05 from the U.S. Public Health Service. (1972)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 134 (1972), S. 23-39 
    Details
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A specific anti-collagen antiserum was prepared in rabbits using as antigen a rat tail collagen preparation free of serum protein reactants. This antiserum reacted with several forms of isolated collagen and with rat urine, but not with rat serum. It was coupled to fluorescein and used to label sites of collagen in frozen and dried cryostat sections of rat tissues. The indirect method, with uncoupled serum, was also used routinely.Tubular and glomerular basement membranes, Bowman's capsule, basement membrane of skin and lung, reticular fibers of spleen and the connective tissue framework of muscle were strongly stained, as was also new bone on trabecular borders and around osteocytes.The supporting fibers of normal hyaline cartilage, calcified bone, most tendons and the deeper fibers of skin were less stained or unstained under identical conditions and are presumably masked or blocked in situ.Cytoplasm or cytoplasmic processes in some fibroblasts of skin and tendon, cytoplasm of osteocytes and some cartilage cells in elastic cartilage were stained.Reaction and masking in fibers are presumably related to the modes of collagen linkage both within the fiber and externally with the ground substance matrix. Activity could be elicited in tendon by a brief heating at 60°C sufficiently to abolish the collagen birefringence. These collagen linkages are believed to be of importance in determining its behavior in overall processes of tissue disaggregation.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/aja.1001340104
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  • 9
    Digitale Medien
    Digitale Medien
    MAPKAP kinase 2 is activated by heat shock and TNF-α: In vivo phosphorylation of small heat shock protein results from stimulation of the MAP kinase cascade (1995)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 57 (1995), S. 321-330 
    Details
    ISSN: 0730-2312
    Schlagwort(e): mitogen activated protein kinases ; heat shock ; TNF-α ; small heat-shock proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: The activation of MAPKAP kinase 2 was investigated under heat-shock conditions in mouse Ehrlich ascites tumor cells and after treatment of human MO7 cells with tumor necrosis factor-α (TNF-α). MAPKAP kinase 2 activity was determined using the small heat-shock proteins (sHsps) Hsp25 and Hsp27 as substrates. In both cell types, about a threefold increase in MAPKAP kinase 2 activity could be detected in a time interval of about 10-15 min after stimulation either by heat shock or TNF-α. Phosphorylation of MAPKAP kinase 2, but not the level of MAPKAP kinase 2 mRNA, was increased after heat shock in EAT cells. It is further shown that activation of MAPKAP kinase 2 in MO7 cells is accompanied by increased MAP kinase activity. These data strongly suggest that increased phosphorylation of the sHsps after heat shock or TNF-α treatment results from phosphorylation by MAPKAP kinase 2, which itself is activated by phosphorylation through MAP kinases. Hence, we demonstrate that MAPKAP kinase 2 is responsible not only for phosphorylation of sHsps in vitro but also in vivo. The findings link sHsp phosphorylation to the MAP kinase cascade, explaining the early phosphorylation of sHsp that is stimulated by a variety of inducers such as mitogens, phorbol esters, thrombin, calcium ionophores, and heat shock.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1002/jcb.240570216
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  • 10
    Digitale Medien
    Digitale Medien
    Signal transduction by transforming growth factor-β: A cooperative paradigm with extensive negative regulation (1998)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 72 (1998), S. 111-122 
    Details
    ISSN: 0730-2312
    Schlagwort(e): TGF-β cooperative signaling ; SMADs ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Transforming growth factor-β (TGF-β) represents an evolutionarily conserved family of secreted factors that mobilize a complex signaling network to control cell fate by regulating proliferation, differentiation, motility, adhesion, and apoptosis. TGF-β promotes the assembly of a cell surface receptor complex composed of type I (TβRI) and type II (TβRII) receptor serine/threonine kinases. In response to TGF-β binding, TβRII recruits and activates TβRI through phosphorylation of the regulatory GS-domain. Activated TβRI then initiates cytoplasmic signaling pathways to produce cellular responses. SMAD proteins together constitute a unique signaling pathway with key roles in signal transduction by TGF-β and related factors. Pathway-restricted SMADs are phosphorylated and activated by type I receptors in response to stimulation by ligand. Once activated, pathway-restricted SMADs oligomerize with the common-mediator Smad4 and subsequently translocate to the nucleus. Genetic analysis in Drosophila melanogaster and Caenorhabditis elegans, as well as TβRII and SMAD mutations in human tumors, emphasizes their importance in TGF-β signaling. Mounting evidence indicates that SMADs cooperate with ubiquitous cytoplasmic signaling cascades and nuclear factors to produce the full spectrum of TGF-β responses. Operating independently, these ubiquitous elements may influence the nature of cellular responses to TGF-β. Additionally, a variety of regulatory schemes contribute temporal and/or spatial restriction to TGF-β responses. This report reviews our current understanding of TGF-β signal transduction and considers the importance of a cooperative signaling paradigm to TGF-β-mediated biological responses. J. Cell. Biochem. Suppls. 30/31:111-122, 1998. © 1998 Wiley-Liss, Inc.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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