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  • 1
    Electronic Resource
    Electronic Resource
    Movement of spermatozoa of Megaselia Scalaris (Diptera: Brachycera: Cyclorrhapha: Phoridae) in artificial and natural fluids (1991)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 210 (1991), S. 85-99 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In artificial fluid, the spermatozoa move as linear cells or round up and rotate, propelled by spontaneous bending of their tails. Both linear and rounded cells can move forward and backward, but usually they move forward. The tails of all cells display, simultaneously, small primary bends and fewer, much larger secondary bends. Rounded cells form single secondary bends that remain unchanged as the cells rotate. They also form “node-like” primary bends that travel posteriorly or anteriorly as the cells rotate forward or backward, respectively. Linear cells move their anterior regions into and out of focus in a cyclic fashion. They form rather prominent primary bends, as well as two to four secondary bends that travel posteriorly as the cells move forward. Secondary bends change in shape continuously and are not sinusoidal. The cells follow approximately linear trajectories, but the distances traveled per cycle, speeds, and secondary bending patterns are variable. When methyl cellulose is added to artificial fluid, linear movement is improved, and forward speeds are approximately tripled. The movement of spermatozoa in natural fluid of the female reproductive tract is remarkably less stereotyped than that of cells in artificial fluid. The cells, usually resembling straight lines or arcs, are very flexible and active. They lack obvious cyclic activity and double bending patterns. They are capable of moving both forward and backward and of adjusting their bending activity and speed within rather wide limits. Their average forward speed is about nine times faster than that of cells in artificial fluid.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1052100108
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  • 2
    Electronic Resource
    Electronic Resource
    Study of selected ions in the ammonia desorption chemical ionization mass spectra of peracetylated gentiobiose and two isotopically labelled peracetylated gentiobioses (1992)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 27 (1992), S. 31-36 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ammonia desorption chemical ionization (NH3-DCI) mass spectra of peracetylated gentiobiose (1) and two isotopically labelled gentiobioses (2 and 3) were examined. Compound 2 is labelled with trideuteroacetyl groups in the non-reducing moiety and 3 with trideuteroacetyl groups in the reducing moiety. It is shown that the [M + NH4 - 42]+ ion is not formed direct from [M + NH4]+ by loss of ketene but appears to be formed by way of a nucleophilic acyl substitution reaction resulting in a neutral species which complexes with NH4+. The disaccharides undergo cleavage at either side of the glycosidic oxygen joining the two sugar residues, a process which is accompanied by addition of H or CH3CO to afford neutral species which complex with NH4+. The structures of the ions resulting from H transfer have been inferred by comparison of their mass-analysed ion kinetic energy (MIKE) spectra with MIKE spectra of the [M + NH4]+ ions of compounds of established structure. A ring fragmentation reaction of 1, 2 and 3 is reported.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210270108
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  • 3
    Electronic Resource
    Electronic Resource
    Progesterone augments proliferation induced by epidermal growth factor in a feline mammary adenocarcinoma cell line (1991)
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 45 (1991), S. 196-206 
    Details
    ISSN: 0730-2312
    Keywords: steroids ; tyrosine kinases/phosphorylation ; RU486 ; p185 neu ; phosphatases ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Steroid hormones and peptide growth factors promote growth and development of normal mammary tissues and some types of breast cancer. Ovarian steroids may influence mammary growth directly or indirectly. The epidermal growth factor (EGF) family of proteins may also regulate mammary growth. These two pathways may function independently of each other or they may act in concert, with steroids inducing transcription of genes that encode growth factors or growth factor receptors. We used a feline mammary adenocarcinoma cell line (K12) to address whether there was an interrelation between progesterone (PGN) and EGF-associated growth pathways. K12 cells responded to EGF by a dose-dependent increase in proliferation. PGN or promegestone (R5020, a synthetic progestagen) alone did not stimulate K12 growth, but when EGF and PGN, or EGF and R5020 were combined, they were synergistic. This synergistic response was abrogated by the PGN receptor antagonist RU486 or by antibodies that blocked binding of EGF to its receptor. K12 cells expressed characteristic double-affinity EGF receptors, as well as p185 (a functionally and structurally related protein, product of the neu gene) on their surface. PGN receptors were also found on intact cells and in cleared cytosols. Stimulation of K12 cells by PGN or by R5020 induced a two- to threefold increase in the number of high-affinity surface EGF receptors after 24 h. Stimulation of these cells by PGN also affected the relative levels of phosphorylation of the EGF receptors and p185 within minutes, but not of other cellular phosphoproteins. Our results show that PGN enhances the EGF-induced growth of K12 cells and suggest that this effect may be mediated at least partly via an increase in the number or function of high-affinity EGF receptors.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcb.240450211
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  • 4
    Electronic Resource
    Electronic Resource
    Confocal imaging of dendritic Ca2+ transients in hippocampal brain slices during simultaneous current- and voltage-clamp recording (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 279-289 
    Details
    ISSN: 1059-910X
    Keywords: Fluorescence microscopy ; Ca channels ; Pyramidal neurons ; CA1 region ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Changes in the intracellular Ca2+ concentration ([Ca2+]i) within CA1 hippocampal pyramidal neurons were imaged using confocal laser scanning microscopy in conjunction with Ca2+ -sensitive fluorescent indicators. The imaging was performed in thick hippocampal brain slices while simultaneously measuring or controlling electrical activity with sharp microelectrodes or whole-cell patch-clamp electrodes. The combination of imaging and electrophysiology was essential for interpreting the changes in [Ca2+]i. We compared the increases in [Ca2+]i produced by either of two methods-direct depolarization of the cell via the somatic electrode or high-frequency stimulations of synaptic inputs. The increases in [Ca2+]i in the soma and proximal dendrites caused by both methods were of comparable magnitude and they always decayed within seconds in healthy cells. However, the spatial patterns of distal Ca2+ increases were different. Separate sets of synaptic inputs to the same cell resulted in different spatial patterns of [Ca2+]i transients. We isolated and observed what appeared to be a voltage-independent component of the synaptically mediated [Ca2+]i transients. This work demonstrates that the combination of neurophysiology and simultaneous confocal microscopy is well suited for visualizing and analyzing [Ca2+]i within neurons throughout the CNS and it raises the possibility of routinely relating subcellular [Ca2+]i changes to structural and functional modifications. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290404
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  • 5
    Electronic Resource
    Electronic Resource
    Role of alveolar macrophage chemotaxis and phagocytosis in pulmonary clearance responses to inhaled particles: Comparisons among rodent species (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 26 (1993), S. 412-422 
    Details
    ISSN: 1059-910X
    Keywords: Complement activation ; Lung clearance ; Carbonyl iron particles ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Alveolar macrophages (AM) play an important role in clearing inhaled particles from the lung. The mechanisms through which macrophages identify particles that have been deposited in the alveolar regions is not well understood, although macrophage motility and phagocytic functions appear to be prerequisites for efficient clearance of inhaled materials. In previous studies, we assessed the mechanisms of macrophage-mediated clearance of inhaled particles using a rat model. In this regard, it appears that one mechanism by which rat alveolar macrophages are recruited to sites of particle or fiber deposition is through complement activation and consequent generation of chemotactic factors by the inhaled particulates. Whether this mechanism is operative in other rodent species remains an unanswered question. The current studies were undertaken to compare pulmonary clearance responses in several rodent species exposed to carbonyl iron (CI) particles. In vitro and in vivo pulmonary clearance responses were evaluated using one strain each of mouse, hamster, rat, and guinea pig. In vitro studies showed that hamster AM had the greatest phagocytic activity and that rat AM migrated best to complement-dependent chemotactic factors. Subsequently, groups of animals from each species were exposed to CI particles for 1 or 6 hr at aerosol concentrations of 100 mg/m3. Particle deposition patterns in the distal lung were nearly identical for all species, although enhanced numbers of CI particles were deposited on alveolar duct bifurcations of either rats or mice compared to hamsters, and particle deposition in guinea pigs was substantially lower. Time course studies showed that enhanced numbers of rat AM migrated to deposition sites and phagocytized particles, and this correlated with increased numbers and percentages of phagocytic macrophages recovered by lavage (P 〈0.01). In vivo phagocytic rates were the lowest in the mouse, and this correlated with reduced phagocytic rates in vitro. It is concluded form these studies that the rat may be the most efficient rodent species in clearing inhaled iron particles. In addition, it is conceivable that hamster AM are recruited to sites of particle deposition by a noncomplement-mediated mechanism. © 1993 Wiley-Liss, Inc.
    Additional Material: 17 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070260509
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  • 6
    Electronic Resource
    Electronic Resource
    Determination of the glycosidic linkage in peracetylated disaccharides comprised of d-glucopyranose units by use ofr desorption electron-ionization mass spectrometry (1991)
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 5 (1991), S. 446-449 
    Details
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: An oxonium ion at m/z 317 is present in the desorption electron ionization and ammonia desorption chemical ionization mass spectra of peracetylated disaccharides, comprised of glucopyranose units linked (1 → 2), (1 → 3), (1 → 4) and (1 → 6), but is absent in the spectra of the (1 → 1)-linked isomer. The ion aat m/z 317, which is derived from the reducing moiety, has an O-formyl group at the position of linkage to the non-reducing moiety, and O-acetyl groups at each of the remaining positions. The iosmeric monoformyl, triacetyl oxonium ions (at m/z 317), derived from the (1 → 2)-, (1 → 3)-, (1 → 4)- and (1 → 6)-linked disaccharides, give distinctly different mass-analysed ion kinetic energy spectra, thereby enabling the linkage position to be assigned unambiguously.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/rcm.1290051005
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  • 7
    Electronic Resource
    Electronic Resource
    Three-dimensional reconstructions of autonomic projections to the gastrointestinal tract (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 29 (1994), S. 297-309 
    Details
    ISSN: 1059-910X
    Keywords: Dil ; Enteric nervous system ; Myenteric ganglia ; Nodose ganglia ; PHA-L ; Submucous ganglia ; Vagus ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: Three-dimensional reconstruction protocols in confocal microscopy are typically considered in terms of rendering separate stacks of optical sections. Single stacks, however, include volumes that are often too small to permit descriptions of entire neurons, complete axonal arbors, or complex neural networks. Furthermore, traditional tissue preparation protocols generally yield specimens too limited to permit reconstructions of complex neural systems. For 3-D analyses of extensive networks such as the autonomic nervous system projections within the viscera, it is critical to incorporate appropriate tissue techniques, including suitable tracer protocols, into the reconstruction strategy. This report summarizes complementary technologies, including whole mount procedures, tracer techniques for identifying single fibers in situ, and methods of examining stacks of optical images, which make it practical to describe the complete terminal field of an individual axon in the gastrointestinal tract. Such methods establish that vagal motor axons travel long distances within their target organs, collateralize frequently, and ramify extensively. Vagal afferents have extensive, complex, and, in some cases, polytopic arbors within target tissues. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070290407
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  • 8
    Electronic Resource
    Electronic Resource
    The independent stage-specific expression of the 18-kDa heat shock protein genes during microsporogenesis in Zea mays L (1993)
    Chichester [u.a.] : Wiley-Blackwell
    Developmental Genetics 14 (1993), S. 15-26 
    Details
    ISSN: 0192-253X
    Keywords: Heat shock protein ; maize ; mi-crosporogenesis ; gametogenesis ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The small (18-kDa) heat shock proteins (hsps) of maize are encoded by a complex multigene family. In a previous report, we described the genetic information from cDNAs encoding two different members of the family. In this communication, we report the isolation and characterization of cDNA and genomic clones encoding information for a third member of this hsp family (c/gMHSP18-1). DNA fragments containing nucleotide sequences common to, or specific for, each of these characterized 18-kDa genes were prepared and used as probes to assess the expression of these genes during microsporogenesis and development of the gametophyte in an inbred line of maize (Oh43). Our results demonstrate (1) that mRNA transcripts encoding the 18-kDa hsps are expressed and/or accumulate during microsporogenesis, and (2) that genes encoding two of the characterized 18-kDa hsps are expressed and/or accumulate independently, in a stage-specific manner during microsporogenesis. These observations imply that the stage-specific expression of particular 18-kDa hsp genes results from gene-specific regulation during microsporogenesis and gametophyte development rather than from an overall activation of the heat shock or stress response. © 1993Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/dvg.1020140104
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  • 9
    Electronic Resource
    Electronic Resource
    Cell cycle activity and expression of prohibitin mRNA (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 157 (1993), S. 289-295 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Prohibitin, a novel intracellular antiproliferative protein, blocks entry into the S phase of the cell division cycle when its mRNA is microinjected into normal fibroblasts or HeLa cells. To learn more about the interaction between prohibitin and the cell cycle, we studied the effect of microinjecting prohibitin mRNA at different points during the transition from G0 to S phase and analyzed prohibitin mRNA and protein levels in different parts of the cell cycle. The antiproliferative activity of microinjected prohibitin mRNA is high in G0/G1 and falls as cells approach S phase. Prohibitin mRNA and protein levels are high in G1, fall with S phase, rise again in G2, and fall in M. Together, these findings suggest that endogenous prohibitin contributes to the control of the G1 to S transition in cycling cells in a complex manner, which involves both a transcriptional and posttranslational mechanism. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041570211
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  • 10
    Electronic Resource
    Electronic Resource
    Insulin-Like growth factor I and protein kinase C activation stimulate pulmonary artery smooth muscle cell proliferation through separate but synergistic pathways (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 144 (1990), S. 159-165 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Smooth muscle cell (SMC) hyperplasia is an important component of vascular remodeling in chronic hypoxic pulmonary hypertension. The mechanisms underlying SMC proliferation in the remodeling process are poorly understood, but may involve insulin-like growth factor I (IGF-I). This study investigates the potential proliferative effects of IGF-I on SMC cultured from the pulmonary arteries (PA) of neonatal calves. We hypothesized that IGF-I stimulates PA SMC proliferation through a protein kinase C (PKC)-indepenent pathway, but that PKC activation would augment this proliferative response. Incorporation of 3H-thymidine was used as an index of cellular prohteration, and was correlated with subsequent changes in cell counts. Under serum-free conditions, IGF-I (100 ng/ml) induced a 6-fold increase in thymidine incorporation by quiescent PA SMC. This stimulation was not blocked by dihydrosphingosine, an inhibitor of PKC activation. Phorbol myristate acetate (PMA) (1 nM), a membrane-permeable PKC activator, induced a 12-fold increase in thymidine incorporation which was 70% inhibited by dihydrosphingosine. Co-incubation with IGF-I and PMA caused a 60-fold increase in thymidine incorporation, which was 30% inhibited by dihydrosphingosine. This synergistic increase in thymidine incorporation was associated with a subsequent significant increase in cell number. PKC-downregulated cells (1,000 nM PMA × 30 hr) proliferated in response to IGF-I but not PMA, and did not demonstrate synergism with the combination of IGF-I and PMA. The threshold concentrations of IGF-I and PMA for synergism were approximately 1 ng/ml and 1 pM, respectively. We conclude that IGF-I stimulates neonatal PA SMC proliferation via a PKC-independent pathway, and that trace amounts of PKC activators are capable of synergistically augmenting this response. We speculate that the synergistic stimulation of SMC proliferation by IGF-I and PKC activators may play an important role in hypertensive pulmonary vascular remodeling.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041440121
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