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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 176 (1983), S. 249-259 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development of middle-ear structures in the mouse was examined in nine groups of pups between 1 and 45 days of age. The area of the tympanic membrane (pars tensa and pars flaccida), the length of the lever arms of the malleus and incus, the surface area of the oval window, and the volume of the bulla all showed systematic changes during neonatal life. The area of the oval window reached maturity first and the lever arms achieved 90% of their adult size on day 11. The tympanic membrane achieved the same criterion on day 18. These data help us further to understand the processes that contribute to the functional ontogeny of the middle ear.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 226 (1995), S. 47-77 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Intratendinous ossification (tenostosis; Tendo ossificans) is a distinct structural form feature of the avian musculoskeletal system with different definitions in terms of morphogenesis, resultant morphology, and functional role(s). Interpretation of these structural elements and their pattern(s) among avian taxa at different systematic levels is reviewed with regard to age-related changes in tendon, form features in avian phylogeny, and adaptive features in biomechanics and kinematics of locomotion. Specific examples of patterns in the musculoskeletal elements of the head and hyolingual system, axial (vertebral) system, and the limbs in several avian taxa are given. A series of questions is formulated as a prospectus for further study. © 1995 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 106 (1981), S. 201-207 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present evidence that extends our earlier preliminary report on the stimulatory effect of saline washes on confluent cells in culture (Lacey et al., '77). That work suggested that an inhibitory substance was being removed by the washes. The present work suggests that the inhibitor is in the 10,000-30,000 MW range, is reversibly bound, is cationic and is also a protease inhibitor. It is heat stable, but is apparently degraded with time in our experimental systems.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 119 (1984), S. 341-348 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spontaneous phenotypic revertants of hypoxanthine phosphoribosyl-transferase (HPRT) temperature-sensitive V79 Chinese hamster cells were selected by plating a temperature-sensitive mutant in HAT medium at 39°C. The incidence of such revertants was approximately 2 × 10-4 per cell. The majority of the revertants examined had increases of between three- and tenfold in their specific activity of the enzyme, and they were able to grow continuously in the presence of HAT medium at 39°C. When the revertants were cultivated in the absence of HAT, they recovered their HAT-sensitive phenotype and their lowered level of HPRT. Three of the revertants were examined for their temperature inactivation profiles, and all were found to have profiles identical to the ts parent, and quite different from the V79 wild type. The kinetic properties of the cell lines were studied:the Km for both PRPP and hypoxanthine was significantly different in the temperature-sensitive cells but was not significantly altered in the revertants with respect to the ts mutants. A specific antibody to Chinese hamster brain HPRT was employed in immunoprecipitation experiments. By measuring the point at which the immunoprecipitation of the antibody to HPRT was overcome by increasing concentrations of cell supernatant, it was possible to estimate the relative amount of enzyme molecules in the cell lines. From these data, it could be concluded that the revertants overproduced an enzyme with the same immunological properties as the ts line. Southern blots of the Hind Ill restricted DNA from the ts mutant and two revertant cell lines were examined with an HPRT cDNA probe. This established that the HPRT gene was amplified twofold in one of the revertants, and threefold in the other. However, if the revertants were reintroduced into nonselective medium, the gene copy number declined to one. Finally, northern blots of RNA extracted from the various cell lines demonstrated that the HPRT mRNA was augmented 1.5-fold in one revertant and 1.4-fold in the other. Reintroduction into non-selective medium resulted in a decline in mRNA level for the second mutant, whereas the first mutant appeared to be stabilized.We conclude that gene amplification and concomitant amplification of messenger RNA and enzyme levels are mechanisms of phenotypic reversion at the HPRT locus in Chinese hamster cells.
    Additional Material: 5 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 241 (1995), S. 563-578 
    ISSN: 0003-276X
    Keywords: Substantia nigra ; Basal ganglia ; Cytoarchitecture ; Light microscopy ; Electron microscopy ; Opossum ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: The substantia nigra has been divided into three subdivisions. However, the cytoarchitecture of one of these subdivisions, the pars lateralis (SNI), has not been previously examined in detail at the light and electron microscopic levels in any species. In the adult opossum, the three nigral subdivisions can be easily distinguished as distinct, rostrocaudally oriented cell groups separated by neuron-free zones. Thus it was possible to determine the boundaries of the SNI unambiguously. This report covers the results of an examination of the morphology and organization of the SNI in the opossum.Methods: Material from 13 opossums was used for this study. Eight of the animals had been previously stained for Nissl substance (n=4) or impregnated by the Golgi technique (n=4). The remaining five animals were prepared for electron microscopic studies using standard procedures.Results: Two cell types were identified on the basis of morphological differences, small and medium-large neurons. Small neurons (10-18 μm long axis) have large nuclei with moderate amounts of heterochromatin and a thin rim of cytoplasm. They have long (up to 500 μm), spine-free dendrites. Medium-large neurons (18-54 μm long axis) have rounded nuclei with electron-lucent nucleoplasm. Few indentations of the nuclear envelope were observed. The surrounding cytoplasm has dense arrays of organelles. Nissl bodies are particularly prominent in the form of pyramids with their bases at juxtanuclear positions and their apices directed toward emerging dendrites. Dendrites of medium-large neurons are long (some〉1 mm in length), are primarily oriented in the frontal plane, and extend along the dorsal surface of or into the cerebral peduncle. Some cells have dendrites that are moderately spinous, whereas other neurons possess sparsely spinous dendrites. Relatively few synaptic profiles are observed to contact somata and proximal dendrites.Conclusion: This report provides added morphological support for the idea that the SNI is a distinct subdivision of the substantia nigra, a distinction previously made on the basis of the physiologically characterized relationship between the lateral substantia nigra and orienting behaviors and seizure-related function. © 1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 241 (1995), S. 439-450 
    ISSN: 0003-276X
    Keywords: Golgi ; TGN ; Inflammation ; Acute phase response ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Background: During the acute phase response to inflammation, the Golgi apparatus of rat hepatocytes processes an increased quantity of glycoproteins, in the form of acute phase reactants.Methods: The compartmental organization of the hepatocyte Golgi of control and 24 hour inflamed rats was studied, using transmission electron microscopic techniques, including cytochemistry, to detect nicotinamide adenine dinucleotide phosphatase (NADPase), thiamine pyrophosphatase (TPPase), and cytidine monophosphatase (CMPase) activity.Results: In inflamed rats, individual Golgi stacks were enlarged, but retained their organization into four compartments:1) a phosphatase negative, perforated cis-element, 2) two mid-saccules which sometimes were positive for NADPase, 3) one or occasionally two NADPase and TPPase positive trans-saccules, and 4) a tubulovesicular trans-Golgi network (TGN) which was NADPase reactive and contained a spotty TPPase reaction product. Two of these compartments were noticably altered in response to inflammation. The two mid-saccules were consistently and uniformly dilated. The TGN was altered to the point of being difficult to recognize and had acquired CMPase reactivity. In control rats the TGN consisted of anastomosing tubules forming cage-like structures; secretory granules containing lipoprotein particles pinched off from these. In inflamed rats, most of the cage-like TGN structures had been replaced with an extensive vesicular syncytium which produced secretory granules with a granulofilamentous content.Conclusions: In hepatocytes from inflamed rats an apparent switch had occured in the type of secretory material processed by the Golgi apparatus. Furthermore, the inflammation-induced increase in the size of individual Golgi stacks apparently was not due to a parallel increase in size of all Golgi saccules. Rather, saccules within given Golgi compartments responded in a characteristic and specific manner to the increase in glycoprotein processing that occurs during inflammation. © 1995 Wiley-Liss, Inc.
    Additional Material: 17 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 197 (1980), S. 205-211 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Studies of Sertoli cell structure, maturation, and function have been aided by the use of in vitro systems. Although numerous papers have appeared that utilize the Sertoli cell culture model, few papers have dealt with the characterization of these cells under various culture environments. Recently, it has been reported that the addition of serum to the culture medium prevents induction of long cytoplasmic appendages in cultured Sertoli cells that have been treated with FSH, TSH, or c-AMP. The purpose of this investigation was to determine which serum components, obtained by gel filtration, are capable of inhibiting the morphological response induced by FSH, TSH, or c-AMP. Sertoli cell-enriched cultures were prepared using collagenase and trypsin digestion, each followed by gravity sedimentation. Untreated cells grown on plastic or glass substrates assumed an epithelioid appearance after several days. Cells treated with FSH, TSH, or c-AMP formed long cytoplasmic appendages after 1-2 days. This response was prevented or reversed by the addition of fetal calf serum (10%), crystallized bovine serum albumin (0.25%-2%), or purified albumin obtained by gel filtration of whole serum (0.25%). It was also found that fractions that elute between the void volume and the initial albumin fractions (molecular weights of approximately 50,000 and greater) mimic the hormone-induced response after only 10-12 hours. The results of this investigation indicate that albumin is the primary serum component responsible for inhibiting morphological alterations induced by FSH, TSH, and c-AMP. Furthermore, it is apparent that the production of long filamentous cytoplasmic appendages in Sertoli cells can be induced by a wide variety of substances.
    Additional Material: 3 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 164 (1982), S. 175-186 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The disappearance of the characteristic supranuclear vacuole and extensive apical canalicular system from enterocytes of the ileal villi occurs during the third postnatal week in rats. This phenomenon is associated with loss of permeability of these cells to macromolecules and is therefore termed closure. The present study was designed to analyze the influence of neonatal guanethidine (GTN)-induced sympathectomy on the morphology of the pre- and postclosure ileum of the rat. Light and electron microscopy of control and GTN-sympathectomized rats demonstrated the retention of immature, vacuolated cells on ileal villi as late as 23 days postnatally in GTN-treated rats. Villi from control rats contained only adultlike nonpermeable cells. Electron microscopy further demonstrated no structural differences in the apical canalicular system or storage vacuoles of the delayed cells in GTN rats when compared to the ileal epithelium from preclosure time periods (7 and 15 days) in both GTN-sympathectomized and control rats. Goblet cells were counted on Periodic-Acid-Schiff-stained sections of ileum from 7, 15, and 23-day GTN and control rats. The percentage of goblet cells in the total epithelial cell population of the villus was significantly higher in control versus GTN rats at all time periods. The percentage of goblet cells increased in both groups from day 7 to 15. However, closure in the control group (approximately day 18) was coincident with a steep increase in the percentage of ileal goblet cells which was not evident in the goblet-cell population of the GTN villus. This pattern of change in control versus GTN goblet-cell production was correlated with a similar pattern of variation in the number of crypt cell mitoses between the two groups over the same time period.
    Additional Material: 11 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 63 (1996), S. 349-357 
    ISSN: 0730-2312
    Keywords: hypercholesterolemia ; nuclear membrane ; NTPase ; hyperlipidemia ; obesity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: A nuclear pore complex-associated nucleoside triphosphatase (NTPase) activity is believed to provide energy for nuclear export of poly(A)+ mRNA. This study was initiated to determine if nuclear membrane lipid composition is altered during chronic hyperlipidemia, and what effect this has on NTPase activity. The JCR:LA-cp corpulent rat model is characterized by severe hypertriglyceridemia and moderate hypercholesterolemia, and thus represents an ideal animal model in which to study nuclear cholesterol and NTPase activity. NTPase activity was markedly increased in purified hepatic nuclei from corpulent female JCR:LA-cp rats in comparison to lean control rats as a function of assay time, [GTP], [ATP], and [Mg2+]. Nuclear membrane cholesterol and phospholipid content were significantly elevated in the corpulent animals. Nuclei of corpulent animals were less resistant to salt-induced lysis than nuclei of lean animals, suggesting a change in relative membrane integrity. Together, these results indicate that altered lipid metabolism in a genetic corpulent animal model can lead to changes in nuclear membrane lipid composition, which in turn may alter nuclear membrane NTPase activity and integrity. © 1996 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 163 (1995), S. 532-537 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hepatocyte growth is regulated by various growth factors, including epidermal growth factor (EGF) and insulin. Recently, several additional peptide hormones have been shown to stimulate growth of hepatocyte only in the presence of EGF or insulin and are thus termed secondary mitogens. Gastrin regulates growth of normal and neoplastic gastrointestinal tissues, but the effect on growth of hepatocyte is unknown. We examined the effect of gastrin on growth of a normal mouse hepatocyte (NMH) line established in our laboratory. Effect of gastrin-17 (G-17) (10-8 to 10-6 M) on growth of NMH cells was examined in either the presence or absence of EGF in the culture medium. Growth of NMH cells was evaluated by incorporation of either bromodeoxyuridine (BrdU) or 3H-thymidine and by counting cells. Presence of a cell-surface receptor for G-17 was determined by Scatchard analysis using 125I-G-17. In the presence of EGF, gastrin stimulated growth of NMH cells; in the absence of EGF, gastrin did not affect growth. The stimulatory effect of gastrin on NMH cells was blocked by JMV 320, a CCK-B type receptor antagonist. NMH cells possess a single, high affinity binding site for gastrin (Kd = 1.2 nM); EGF increased the gastrin binding capacity compared to non-treated cells (3.5 ± 0.4 vs. 2.2 ± 0.6 fmol/106 cells). G-17 stimulated growth of NMH cells through a single high affinity receptor for G-17 which pharmcologically appears to be the CCK-B type only in the presence of EGF and thus can be considered a secondary mitogen. © 1995 Wiley-Liss, Inc.
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