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  • 1
    Electronic Resource
    Electronic Resource
    Mouse oocyte maturation is affected by lithium via the polyphosphoinositide metabolism and the microtubule network (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 38 (1994), S. 187-199 
    Details
    ISSN: 1040-452X
    Keywords: Mouse oocyte ; Meiosis ; Lithium ; InsP3 ; myo-inositol ; Chromatin ; Microtubules ; Cell cycle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The incubation of mechanically denuded mouse oocytes in medium containing LiCl delayed both germinal vesicle breakdown (GVBD) and polar body extrusion in a dose-dependent and reversible manner. When myo-inositol alone was added to the culture medium, we observed that it accelerated GVBD and increased the rate of polar body extrusion, whereas, when combined with LiCl, the normal timing of GVBD was recovered. In the same way, when inositol trisphosphate (InsP3) was microinjected into the ooplasma, we observed an important improvement of the rate of GVBD, as compared to control oocytes, and prevention of lithium inhibition. However, neither myo-inositol nor InsP3 were able to rescue totally the oocytes from the negative effect of lithium on polar body extrusion. Moreover, lithium induced some important changes in microtubule and chromosome organizations. Before extrusion of the first polar body, the reduction of the spindle size or the appearance of short individualized chromosomes dispersed around a large aster of microtubules were often observed, whereas, after polar body extrusion, the spindle appeared smaller and chromosomes were often trapped in the midbody. Thus lithium affects mouse oocyte maturation at two different levels: GVBD and polar body extrusion. Whereas the former seems to be affected via polyphosphoinositide turnover, the latter is InsP3-independent and seems to be influenced negatively via underdevelopment of microtubular structures. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1080380210
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  • 2
    Electronic Resource
    Electronic Resource
    Vascularization of the mouse embryo: A study of flk-1, tek, tie, and vascular endothelial growth factor expression during development (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Developmental Dynamics 203 (1995), S. 80-92 
    Details
    ISSN: 1058-8388
    Keywords: Receptor tyrosine kinases ; Vascularization ; Mouse embryo ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: We report the detailed developmental expression profiles of three endothelial specific receptor tyrosine kinases (RTKs) flk-1, tek, tie, as well as vascular endothelial growth factor (VEGF), the flk-1 ligand. We also examined the expression of the other VEGF receptor, flt-1, during placental development.flk-1, tek, and tie transcripts were detected sequentially at one-half day intervals starting at E7.0, suggesting that each of these RTKs play a unique role during vascularization of the mouse embryo. All three RTKs were expressed in the extraembryonic and embryonic mesoderm in regions that eventually give rise to the vasculature. Except for the expression of tek and flk-1 in the mesoderm of the amnion, the expression of these RTKs from E8.5 onwards was virtually indistinguishable. An abundant amount of flt-1 transcripts was found in the spongiotrophoblast cells of the developing placenta from E8.0 onwards. This cellular compartment is located between the maternal and labyrinthine layers of the placenta, which both express VEGF. VEGF transcripts were detected as early as E7.0 in the endoderm juxtaposed to the flk-1 positive mesoderm, and later in development VEGF expression displayed an expression profile both contiguous with that of flk-;1, and also in tissues found some distance from the flk-1-expressing endothelium. These results suggest a possible dual role for VEGF which includes a chemotactic and/or a cellular maintenance role for VEGF during vascularization of the mouse embryo. ©1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1002030109
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  • 3
    Electronic Resource
    Electronic Resource
    Quantitative X-ray microanalysis of P, Ca, and S in the mucus secretory granules of the cryofixed frog palate epithelium (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Microscopy Research and Technique 28 (1994), S. 141-148 
    Details
    ISSN: 1059-910X
    Keywords: X-ray microanalysis ; Respiratory epithelium ; Secretory cells ; Cryofixation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Notes: In respiratory epithelium, the mucus is densely packed inside the secretory granules (SG) of secretory cells (SC) before being released by exocytosis in the airway lumen. We have previously shown that the frog palate is a representative model of respiratory epithelium and that rapid cryofixation is a very effective technique in preserving the integrity of the mucus SG. The concentration of phosphorus (P), sulphur (S), and calcium (Ca) were analysed inside the SG of the SC of frog palate after quick freezing, cryosubstitution, and embedding in Lowicryl resin at low temperature. The experiments were carried out using X-ray microanalysis conducted with energy dispersive spectrometry (EDS) at 100 kV. The quantitation was carried out using the continuum method with reference to Agar standards. The cryofixation permitted us to distinguish two types of SG depending on whether they were electron dense (serous cells) or electron-lucent (mucous cells). A significant (P 〈 0.001) difference in the S concentration was observed between the individual serous (239 ± 79 mmol.kg-1) and the mucous SG (161 ± 48 mmol.kg-1). No significant difference could be identified in the Ca concentration between the two SG phenotypes. In the serous SG, the P content was high (41 ± 17 mmol.kg-1) compared with the mucous SG where it was not measurable. The comparison of the three element concentrations in each type of secretory cells showed that significant differences in concentration of S and Ca concentration could be observed from one SC cell to another. A significant correlation (r = 0.76, P 〈 0.01) was observed between the S concentration and the topographical position of the SG inside the SC, the more proximal to the lumen, the higher the S concentration, suggesting that the maturation of the SG involves an increase in the protein content possibly due to a maturation process before the mucus exocytosis. Therefore, these results suggest that the elemental composition of granules varies according to the phenotype of the secretory cells and that changes in the S content from one SG to another or even inside the same cell may reflect a differential state in the functional activity of the secretory cells. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jemt.1070280205
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  • 4
    Electronic Resource
    Electronic Resource
    Quantitative assay of electromyograms during mastication in domestic cats (Felis catus) (1980)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 163 (1980), S. 253-281 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mastication has been studied by cinematography with synchronized electromyography (computer quantified and analyzed), while unanesthetized, freely feeding cats (Felis catus) were reducing equivalent-sized chunks of raw and cooked beef and cooked chicken. Cats reduce food on one side at a time, and their chewing cycles show both horizontal and anteroposterior deflections. Food objects are shifted from side to side by lateral jerks of the head and movements of the tongue.During the opening phase, the lower jaw is rotated relatively straight downward, and the digastric muscles are active in bilateral symmetry. Near the end of opening, the head jerks upward, both zygomaticomandibulares start to fire, and opening acceleration of the mandible decreases. Closing starts with horizontal displacement of the mandibular canines toward the working side, accompanied by asymmetrical activities from the working side deep temporalis and the balancing side medial pterygoid, as well as a downward jerk of the head. As closing proceeds, the mandibular canines remain near the working side and the working side zygomaticomandibularis and deep masseter are very active. Near the end of closing, the mandibular canine on the working side moves toward the midline, and adductors, digastrics, and lateral pterygoids of both sides are active. The adductors of the working side are generally more active than those of the balancing side.During a reduction sequence, the number and shape of the masticatory cycles, as well as movements of the head, during a reduction sequence are affected significantly by food type. As reduction proceeds, the duration of bite and the muscular activity (as characterized by number and amplitude of spikes) change significantly among muscles of the working and balancing sides. The adductors of the working side are generally most active when cats chew raw beef, less for cooked beef, and least for cooked chicken. In general, the adductor activity reflects food consistency, whereas that of the digastrics and lateral pterygoids reflects more the vertical and lateral displacements of the mandible. Statistical analysis documents that the methods of electrode insertion and test give repeatable results for particular sites in different animals. Thus, it should be possible to compare these results with those produced while other mammalas are masticating.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051630304
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  • 5
    Electronic Resource
    Electronic Resource
    Cranial kinetics of the generalized colubrid snake elaphe obsoleta quadrivittata. I. Descriptive morphology (1959)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 105 (1959), S. 193-239 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051050202
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  • 6
    Electronic Resource
    Electronic Resource
    Cranial kinetics of the generalized colubrid snake elaphe obsoleta quadrivittata. II. Functional morphology (1959)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 105 (1959), S. 241-291 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051050203
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  • 7
    Electronic Resource
    Electronic Resource
    Feeding in golden hamsters, Mesocricetus auratus (1977)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 154 (1977), S. 427-458 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Simultaneous cine and electromyographic records of freely feeding, unanesthetized golden hamsters show that their motion and muscular activity during mastication differ from those of albino rats (Weijs, '75). Rats show only propalinal motion while hamsters show lateral translation as well. The masticatory muscles of hamsters and rats are generally similar, but their molar dentitions differ. The interlocking molar cusps of hamsters restrict propalinal protrusion and retrusion when the molars are in occlusion; however, hamsters readily unlock occlusion by a twisting movement in the horizontal plane. Rats may perform propalinal movements even with the teeth in occlusion.In mastication the hamstery's jaw moves laterally as well as vertically and anteroposteriorly. Chewing orbits typically reverse after one to three orbits. Reversal begins at the start of the upstroke and involves a lateral shift in the opposite direction with the mouth closed.Electromyograms show that symmetric and asymmetric activities of closing protrusive and closing retrusive muscles produce a unilateral force couple on both sides. (This couple accompanies a midline closing stroke.) When the mouth is closed, unilateral activity of closing retrusors and closing protrusors also induces lateral translation. A bilateral force couple pits the retrusors of one side against the protrusors on the opposite side. Simultaneous with lateral excursion to the opposite side of midline and the action of these closing muscles, the anterior digastric and lateral pterygoid muscles of one side fire asymmetrically.The mandible moves downward coincidently with bilateral activity of the digastrics and lateral pterygoids. As the jaw opens further, activity differences of the lateral pterygoids accompany a shift of the mandible toward midline. At the end of the downstroke, all masticatory muscles studied are silent. The jaw returns to midline when the adductors fire asymmetrically at the start of closing.Trituration appears to coincide with an initial simple protrusion, which is subsequently accompanied by lateral translation. Different food types are reduced by distint chewing patterns with the differences clearest when the teeth are near occlusion. During gnawing the lateral pterygoids and digastrics fire longer, and the closing muscles fire less strongly. Chewing patterns in golden hamsters appear more generalized than those of rats; the differences may be directly associated with the ability of hamsters to store food in their cheek pouches.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051540305
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  • 8
    Electronic Resource
    Electronic Resource
    Putrescine dependent growth of mycoplasma infected mammalian cells (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 114 (1983), S. 16-20 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The aliphatic diamine putrescine, a metabolic precursor of the polyamines spermidine and spermine, markedly stimulated the growth of a murine lymphoblastoid cell line (R 1.1) infected with Mycoplasma orale, under conditions of arginine limitation. The diamine acted by suppressing the growth of the mycoplasma, which use arginine as a major energy source, and thereby prevented the depletion of arginine from the medium. The antimycoplasmal effects of putrescine occurred at concentrations that were neither stimulatory nor toxic to uninfected cells.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041140104
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  • 9
    Electronic Resource
    Electronic Resource
    Regulation of deoxyglucose uptake by adrenocorticotropic hormone in cultured neurons (1985)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 124 (1985), S. 75-80 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The influence of ACTH and some of its N-terminal related peptides was investigated on the uptake of (3H)-2-deoxy-D-glucose in pure cultures of neurons from chick embryo cerebral hemispheres. ACTH influences deoxyglucose uptake in a time and dose-dependent fashion. The stimulation of deoxyglucose uptake is observed after a delay of 6-8 h and requires active protein synthesis. ACTH does not affect deoxyglucose in non-neuronal cells (astroglial cells, hepatocytes, myoblasts, fibroblasts). The effect of various peptide hormones, neuropeptides and growth factors, active in the central nervous system or other tissues, has also been examined. None of these were able to stimulate deoxyglucose uptake, suggesting that the regulation of hexose uptake in neurons is specific for the ACTH-related peptides.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041240113
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  • 10
    Electronic Resource
    Electronic Resource
    Mitogenic stimulation of human breast cancer cells in a growth factor-defined medium: Synergistic action of insulin and estrogen (1988)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 134 (1988), S. 101-108 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cooperative action of 17β-estradiol (E2) and polypeptide growth factors in stimulating proliferation of human breast cancer cells in vitro was investigated. To prevent background estrogenic stimulation, only phenol red-free media were used. When cultured in media supplemented with steroid-stripped serum in which all polypeptide growth factor activity had been chemically inactivated, MCF7 cells were unable to proliferate and became virtually quiescent. In the additional presence of insulin, epidermal growth factor (EGF), and E2, however, cells proliferated as rapidly as did cells cultured in media supplemented with fetal calf serum. Analysis by DNA flow cytometry showed that in the absence of external growth factors, MCF7 cells became arrested predominantly in the G1/G° phase of the cell cycle. Upon addition of insulin in combination with EGF and E2, however, cells reentered the cell cycle with a high degree of synchrony. When added alone, E2 induced only slight mitogenic effects under these growth factor-defined conditions. In contrast, this steroid induced optimal proliferation in conventional steroid-stripped serum, which in itself contained considerable mitogenic activity. Insulin (at 10 μg/ml) was the most potent stimulator of MCF7 cell proliferation under growth factor-defined conditions, resulting in a more than sixfold increase in cell number after 96 hours. Other growth factors such as platelet-derived growth factor (PDGF), transforming growth factor β (TGFβ), and EGF had little effect by themselves and only slightly influenced insulin-induced proliferation. At suboptimal concentrations of insulin (10-100 ng/ml), however, strong synergism was observed between E2 and insulin in inducing MCF7 proliferation. Using the CG5 cell line, a highly E2-sensitive MCF7 variant, synergism with E2 was already observed at 1 ng/ml insulin. It is concluded that MCF7 cells require insulin (or insulin-like growth factors) for proliferation. At suboptimal insulin concentrations, E2 acts synergistically with insulin, possibly by inducing autocrine production of polypeptide growth factors by these cells.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041340112
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