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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 153-158 
    ISSN: 0886-1544
    Keywords: giant smooth muscle fiber ; ctenophore ; myofilaments ; ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Bundles of giant smooth muscle fibers of the ctenophore Beröe have been stretched up to four times their initial length and then examined by transmission electron microscopy. Stretching induces the segregation of actin and thick (myosinlike) filaments into separate domains. The thick filaments domains are made of 20-30 filaments, with a regular spacing identical to that of nonstretched fibers. A moderate stretching permits the visualization of microtendons associating actin filament bundles to hyaluronidase-resistant condensations of the extracellular matrix. It is deduced from these observations that Beröe giant smooth muscle fibers possess myofibrils which attach at both ends upon the sarcolemmal membrane. Each myofibril is probably made of two long actin filament bundles (of approximately 150 filaments) and short (2-3 μm) myosinlike bundles (of approximately 30 filaments).
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 502-509 
    ISSN: 0886-1544
    Keywords: respiratory cilia ; dynein ; ATPase ; cystic fibrosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Isolated ciliary axonemes from pig trachea were exposed to increasing concentrations of purified Pseudomonas aeruginosa rhamnolipid. This is a defined ciliary system allowing observation of direct impairment of functional axonemes. Axonemal motility and ATPase activity were decreased in proportion to rhamnolipid concentrations. ATPase-associated proteins observed in sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and dynein arms seen in ultrastructural cross sections progressively disappeared from axonemes with exposure to rhamnolipid. These four independent measures establish that the rhamnolipid removes the ATPase-containing outer dynein arms from the ciliary axoneme, thereby rendering the axoneme immotile.
    Additional Material: 4 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 141 (1989), S. 653-659 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Endothelial cell (EC) motility may contribute to the regulation of microvascular perfusion and/or paracellular permeability. The experiments reported herein demonstrate that bovine pulmonary microvessel EC can reversibly deform a silicone substrate in response to agents known to contract and relax smooth muscle cells. Contracting pulmonary microvessel EC exerted a tension that created wrinkles in the underlying deformable substrate. Relaxation and loss of tension were revealed by the disappearance of these wrinkles without loss of cell adhesion to the substratum. Angiotensin II (Ang II) and bradykinin stimulated pulmonary microvessel EC to contract within 3 to 8 min in a Ca2+-dependent fashion. The peak of contraction at 10 to 20 min was followed by relaxation. Forskolin and sodium nitroprusside (SNP) initiated relaxation of the microvessel EC within 3 to 10 min respectively. Relaxed EC contracted following the addition of Ang II, also within 3 min. Dibutyryl cAMP, dibutyryl cGMP, and the photoactivated internalized “caged” cAMP and cGMP promoted EC relaxation in a manner similar to forskolin and SNP. Increases in the intracellular concentration of inositol triphosphate (IP3) with the photoactivated IP3 complex promoted EC contraction in 2 min with a peak at 7 min. The contraction was followed by relaxation, which occurred at 20-25 min. Neither bovine pulmonary artery nor retinal microvessel EC, used as controls, contracted under these experimental conditions. One could speculate that this unique contractile property of pulmonary microvessel EC as observed in vitro may play a regulatory role in vivo, in local perfusion and/or in intercellular gap regulation.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 124 (1985), S. 191-198 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Differentiatio of 3T3-L1 adipocytes, monitored by accumulation of neutral lipid and by increase in α-giycerophosphate dehydrogenase activity, is accelerated by incubation of confluent 3T3-L1 fibroblasts in media containing insulin, dexamethasone and isobutylmethylxantine (IBMX). IBMX inhibits cyclic nucleotide phosphodiesterases as well as the binding of adenosine to its recetor. Agents with relatively specific effects were utilized to examine the role of IBMX in differentiation. Ro 20-1724, a selective inhibitor of soluble cAMP phosphodiesterase activities, was as effective as IBMX in increasing α-glycerophosphate dehydrogenase activity and fat deposition. Neither cilostamide, which inhibits particulate but not soluble cAMP phosphodiesterase activities, 8-phenyltheophylline, an adenosine receptor antagonist with little inhibitory effect on phosphodiesterase activities, nor N6-(R phenyl-isopropyl) adenosine (PIA), a potent adenosine receptor agonist, were effective in promoting differentiation. In addition, we find that maximal increases in α-glycerophosphate dehydrogenase activity and lipid accumulation were observed when differentiation was initiated in the presence of 10 nM dexamethasone. These data suggest that inhibition of soluble cAMP phosphodiesterase activity and subsequent alterations in cAMP may play an important role in the mechanism whereby IBMX enhances differentiation of 3T3-L1 cells.
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  • 5
    ISSN: 0148-7280
    Keywords: pig ; oocyte maturation ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In order to investigate whether the follicular tissue influences cumulus-oocyte interaction and, consequently, the fertilizability of the egg, four experiments were carried out. In the first, cumulus-enclosed pig oocytes were cultured for 44 h in control medium (modified TCM-199) or in follicle-conditioned medium, and the intercellular coupling was studied by measuring 3H-uridine uptake. In control medium the intercellular cooperation started to decline immediately, and at 24-32 h the uncoupling was almost complete. By contrast, in follicle, conditioned medium, it remained at high levels until 24-32 h. In the second experiment protein synthesis patterns of oocytes were studied. Oocytes cultured in conditioned medium were characterized by a 45-kD protein band, while those maturing in control medium were identifiable by a marked 56-kD band. In the third experiment mature oocytes were fertilized in vitro. The percentage of penetrated egg was higher in oocytes matured in conditioned medium than in control medium. In addition, only oocytes matured in conditioned medium could consistently decondense spermatozoa and form male pronuclei. Metabolic cooperation, protein synthesis patterns, and fertilizability were also studied in oocytes matured in control medium supplemented with either 17β-estradiol or progesterone or testosterone or dihydrotestosterone or androstenedione or ether extract of conditioned medium. Only ether extract and progesterone stimulated cumulus oocyte interaction and sperm decondensation. In the last experiment oocytes denuded at different stage of their maturation in conditioned medium were fertilized in vitro. The longer the eggs were cultured with the cumulus, the higher was their penetrability. Moreover, only oocytes denuded after 40 h of culture could, once fertilized, promote the formation of male pronuclei.These data demonstrate that follicular secretions are fundamental for the maintenance in vitro of a functional intercellular coupling between cumulus and oocyte, which is necessary for the egg to become penetrable by spermatozoa and to acquire the conditions required for the formation of male pronuclei.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 22 (1989), S. 333-338 
    ISSN: 0148-7280
    Keywords: ultrasound ; ovulation ; hyperthermia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In vitro fertilization and embryo transfer (IVF-ET) programs use ultrasound extensively for monitoring the growth of ovarian follicles and, subsequently, for confirming the presence of a fetal sac. There have been few reports of the effects of ultrasound on ovulation rates in mammals, and we report here that following exposure to continuous wave ultrasound at a spatial average intensity of 3.0 W/cm2 for five minutes, ovulation rates measured 10 days later were significantly reduced in mice. When temperature elevation of the exposed ovary was measured with a thermocouple, hyperthermia correlated with reduction in ovulation.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 18 (1987), S. 319-332 
    ISSN: 0148-7280
    Keywords: sperm membrane ; stallion spermatozoa ; spermatic maturation ; ultrastructural cytochemistry ; cellular microelectrophoresis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The structure, relative density, and distribution of anionic sites on the surface of epididymal and ejaculated spermatozoa were studied using polycationic ferritin (CF), colloidal iron hydroxide (CIH), various enzymatic treatments, methylation, and de-acetylation. Macro-molecules containing sugar residues, probably sialic acid, are part of the sperm membrane and show a characteristic distribution and density that is dependent of the sperm region and of its origin. Unlike the spermatozoa of other eutheria examined, the exposure of the stallion spermatozoa to neuraminidase treatment did not produce significant changes in the density of the negative charge of the sperm surface. The ability of purified neuraminidase to act only after saponification suggests that sialic acid may be present in the acetylated form. When CIH was used it is seen that the density of the negative charge is rather uniform within a particular segment of the spermatozoa and abruptly changes at the junction of morphologically distinct segments (Between the acrosomal and post acrosomal region of the sperm head and between the post acrosomal region and middle piece of the flagellum). The acrosome presented more negative groups dissociated at pH 1.8 than the postacrosomal region. A greater concentration of anionic sites over the flagellum was also observed when CIH and CF were used. This assymetry probably represents different domains that may be related to specific functions.The cytochemical observations and the cellular electrophoretic mobility measurements did not show striking differences on the negative charge of sperm obtained from different regions of epididymis and ejaculates in contrast to previous results in other species. The spermatozoa collected from caput epididymidis bind CIH but not all population present equal response. In corpus and cauda region of epididymis the population displaying the capacity to bind CIH or CF significantly over the head and tail surface was the majority.This study corroborates that the distribution and density of terminal oligosaccharide residues on the sperm plasma membrane has species specific characteristics. The surface charge of the spermatozoa obtained either during the breeding or nonbreeding season, determined by measurements of cellular electrophoretic mobility and by the binding pattern of CIH and CF, does not show significant differences.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 138 (1989), S. 579-585 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dipeptide transport was studied in chicken enterocytes and its properties compared with those of Na+-dependent sugar transport. Results showed that 1) isolated cells were capable of accumulating glycylsarcosine (Gly-Sar) against a concentration gradient (2.5- to 3.0-fold accumulation). This uptake was maximal at pH 6.0, and it was inhibited by Na+-free medium and by ouabaine; 2) uptake of Gly-Sar was not affected by methionine and was competitively inhibited by carnosine, with a Ki of 12 mM; 3) the protonophore FCCP inhibited both Gly-Sar and 3-oxy-methyl-D-glucose (3-OMG) uptake by the cells; 4) amiloride, a well-known inhibitor of the Na+/H+ exchanger system stimulated 3-OMG uptake and inhibited Gly-Sar uptake, its effects being greater at pH 7.4; 5) and monensine prevents the effects of amiloride on both sugar and dipeptide uptake. In summary, Gly-Sar uptake depends on extracellular Na+ in an indirect manner via its effect on H+ efflux, and it appears to be dependent on an inward H+ gradient.
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  • 9
    Publication Date: 1986-04-25
    Description: The Syrian cardiomyopathic hamster has a hereditary disease in which a progressive myocardial necrosis mimics human forms of cardiac hypertrophy. Lesions are associated with calcium overload and can be prevented with the calcium antagonist verapamil. Numbers of receptor binding sites for calcium antagonists in heart, brain, skeletal muscle, and smooth muscle were markedly increased in cardiomyopathic hamsters. The uptake of calcium-45 into brain synaptosomes was also increased in cardiomyopathic hamsters. The increase in calcium antagonist receptors and related voltage-sensitive calcium channels may be involved in the pathogenesis of this cardiomyopathy.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Wagner, J A -- Reynolds, I J -- Weisman, H F -- Dudeck, P -- Weisfeldt, M L -- Snyder, S H -- HL-17655/HL/NHLBI NIH HHS/ -- MH-18501/MH/NIMH NIH HHS/ -- NS-16375/NS/NINDS NIH HHS/ -- etc. -- New York, N.Y. -- Science. 1986 Apr 25;232(4749):515-8.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3008330" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Brain/metabolism/physiopathology ; *Brain Chemistry ; Calcium/metabolism ; Calcium Channels ; Cardiomyopathy, Hypertrophic/*physiopathology ; Cricetinae ; Disease Models, Animal ; Female ; Heart/physiopathology ; Male ; Mesocricetus ; Muscle, Smooth/analysis/metabolism ; Muscles/*analysis/metabolism/physiopathology ; Myocardium/*analysis/metabolism ; Nifedipine/analogs & derivatives/metabolism ; Nitrendipine ; Receptors, Nicotinic/*analysis/metabolism/physiology ; Synaptosomes/metabolism ; Verapamil/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 10
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1987-12-04
    Description: 〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Dunn, A J -- Powell, M L -- Gaskin, J M -- MH25486/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1987 Dec 4;238(4832):1423-5.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Neuroscience, College of Medicine, University of Florida, Gainesville 32610.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3685987" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Corticosterone/*blood ; Female ; Hypophysectomy ; Lymphocytes/physiology ; Male ; Mice ; Mice, Inbred Strains ; Models, Biological ; Newcastle Disease/*blood ; Pituitary-Adrenal System/*physiopathology ; Postoperative Complications/blood ; Stress, Physiological/blood
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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