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  • 1980-1984  (5.947)
  • Life and Medical Sciences  (4.919)
  • Rat  (616)
  • Gas chromatography  (412)
  • Nuclear reactions
Materialart
Erscheinungszeitraum
Jahr
  • 101
    ISSN: 1432-0738
    Schlagwort(e): Methyl mercury ; Toxicokinetics ; Differential toxicity ; Japanese quail ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Distribution of a single oral dose of methyl mercury (10 mg Hg/kg body weight) was followed from 90 min up to 120 h in plasma, erythrocytes, and brain of Japanese quails and rats. Significantly higher Hg concentrations were observed in plasma and brain of quails and red blood cells of rats. Blood/brain ratio decreased in quails from 6 to 2 at 24 h and 120 h respectively, whereas it increased in rats. Erythrocyte/plasma ratio in quails was about three times lower and averaged 54. The differences in Hg distribution were accompanied by a more than 3-fold higher acute toxicity in quails under adequate experimental conditions.
    Materialart: Digitale Medien
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  • 102
    Digitale Medien
    Digitale Medien
    Springer
    Archives of toxicology 55 (1984), S. 272-275 
    ISSN: 1432-0738
    Schlagwort(e): 2-Ethoxyethanol ; Teratogen ; Adsorption ; Desorption ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract A gas Chromatographic procedure for the determination of 2-ethoxyethanol (C2H5OCH2CH2OH) was developed by using the general principles of analysis of solvent vapors. 2-Ethoxyethanol was sampled by adsorbing on activated carbon. It was desorbed with carbon disulfide plus 2-propanol (0.5%). The analytical column was packed with 10% free fatty acid phase on Chromosorb-P AW. The analysis was conducted at 130° C isothermal using a flame ionization detector. Addition of 2-propanol (0.5%) to carbon disulfide improved (P≤0.01) desorption of 2-ethoxyethanol adsorbed on activated carbon. The mean desorption efficiency of carbon disulfide plus 2-propanol (0.5%) was 87.9±2.86% (n=15). Based on a 101 air sample and detector sensitivity of 2×10−10AFS, the calculated limit of detection of 2-ethoxyethanol was 0.1 ppm. The precision (coefficient of variation) for this analytical procedure was 3.34% (n=12). In conclusion, 2-ethoxyethanol adsorbed on activated carbon can be desorbed with carbon disulfide plus 2-propanol (0.5%). Subsequently the desorbed 2-ethoxyethanol can be analyzed by gas chromatographic identification on 10% FFAP using a flame ionization detector.
    Materialart: Digitale Medien
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  • 103
    Digitale Medien
    Digitale Medien
    Springer
    Journal of cancer research and clinical oncology 108 (1984), S. 56-59 
    ISSN: 1432-1335
    Schlagwort(e): DNA methylation ; Rat ; Procarbazine
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The cytostatic drug procarbazine has previously been shown to be a potent transplacental neurotropic carcinogen in rats. Following a single IP administration of (14C-methylprocarbazine (110 mg/kg) on day 22 of gestation, methylation products with cellular DNA were determined in fetal and maternal rat organs. The concentration of the major adduct N7-methylguanine was highest in the maternal liver (224 μmol/mol guanine). Fetal and nonhepatic maternal tissues exhibited significantly lower levels, but differed little from each other. In brain, lung, intestines, and placenta the O 6-methylguanine/N7-methylguanine ratio was close to 0.11, indicating that procarbazine, like other methylating carcinogens, initiates malignant transformation via methyldiazonium hydroxide as the ultimate reactant. Following a single dose of (14C-methyl)procarbazine to newborn animals, methylpurine values were 30–60 times lower than after prenatal administration. This suggests that DNA alkylation in nonhepatic tissues occurs by systemic distribution of a proximate carcinogen formed in the adult rat liver.
    Materialart: Digitale Medien
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  • 104
    Digitale Medien
    Digitale Medien
    Springer
    Journal of cancer research and clinical oncology 108 (1984), S. 114-120 
    ISSN: 1432-1335
    Schlagwort(e): Nasal cavities ; Rat ; DOPN
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Weekly SC administration of 2,2-dioxopropylnitosamine to 88 Sprague-Dawley rats resulted in the induction of 76 separate neoplasms in the respiratory region of the nasal cavities. No tumors of the olfactory region were found. Histologically there were 37 squamous papillomas, 17 transitional papillomas, and 22 squamous cell carcinomas. These tumors were compared with a selected group of 53 related human tumors of the nasal and paranasal cavities, consisting of 11 squamous cell papillomas, 13 transitional papillomas, and 29 squamous cell carcinomas. While the experimental squamous cell papillomas showed a striking histological resemblance with the squamous papillomas observed in man, none of the experimental transitional papillomas had evidence of the characteristics inverted pattern seen in humans: nevertheless, the experimental tumors showed signs of incomplete squamous metaplasia and preservation of intraepithelial secretory glands, features commonly seen in transitional papillomas of man. The squamous cell carcinomas of this experiment were very similar to the corresponding human tumors in morphology and sex incidence. In both species a significant number of squamous cell carcinomas were keretinizing and of a high grade of histological malignancy. In addition, 69% of the human squamous cell carcinomas occurred in the male sex, and 72% of the experimental carcinomas developed in males. This comparative study suggests that further studies investigating the significance of nitrosamines as suspected etiologic factors of nasal carcinogenesis in man may be useful.
    Materialart: Digitale Medien
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  • 105
    ISSN: 1432-2072
    Schlagwort(e): Diazepam ; Prenatal ; Early postnatal treatment ; Learning disabilities ; Hyperactivity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract In the present study we have investigated the effects of diazepam (DZP) (10 mg/kg) treatment of rat dams during different periods of gestation or during lactation on the development and behavior of their offspring. The results show that DZP exposure during different phases of early development has differing effects on later behavior. Exposure during mid-gestation resulted in early and transient hyperactivity, but no learning or memory deficits at 2 months of age were observed. However, both late prenatal and early postnatal exposure to DZP resulted in significant behavioral changes. Late prenatal treatment caused no hyperactivity but resulted in poor performance on the learning and retention of a choice discrimination task, while early postnatal exposure resulted in consistent and lasting hyperactivity and in substantial discrimination learning and retention deficits at 2 months of age.
    Materialart: Digitale Medien
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  • 106
    Digitale Medien
    Digitale Medien
    Springer
    Psychopharmacology 83 (1984), S. 88-92 
    ISSN: 1432-2072
    Schlagwort(e): Ethanol ; Behaviourally augmented tolerance ; Physiological tolerance ; Muscarinic receptor ; Operant conditioning ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Two groups of adult male rats were injected daily with ethanol (1.5 g/kg IP in 15% w/v solution) either before (the behaviourally augmented tolerant group) or after (the physiologically tolerant group) being placed in operant chambers. The control groups received daily isotonic saline injections either before or after the operant task. When challenged with ethanol (2.5 g/kg) on day 30 prior to the operant task, the control group was most impaired, while the behaviourally augmented tolerant group was significantly less impaired than the physiologically tolerant group. The two ethanol-treated groups were impaired to the same extent when challenged on day 60. Partial generalization of this behavioural tolerance to ethanol was observed, as the behaviourally augmented tolerant group was less impaired than the physiologically tolerant group for a tail flick response to painful stimuli after an ethanol challenge on day 30. However, the two ethanol-treated groups exhibited similar impairments of locomotor activity after an ethanol challenge on day 40. No differences in muscarinic receptor binding among the control and two ethanol-treated groups were found. These findings demonstrate that behaviourally augmented tolerance to ethanol may be partially generalizable but is unrelated to changes in muscarinic cholinergic receptors.
    Materialart: Digitale Medien
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  • 107
    Digitale Medien
    Digitale Medien
    Springer
    Pflügers Archiv 401 (1984), S. 414-417 
    ISSN: 1432-2013
    Schlagwort(e): Brown adipose tissue ; Microspheres ; Noradrenaline ; Rat ; Regional blood flow ; Xenon clearance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The xenon clearance method was adapted to continuous measurement of interscapular brown adipose tissue (ISBAT) blood flow in anaesthetized rats. The ISBAT-blood partition coefficient for xenon was determined to 3.6 ml·g−1. The blood flow values obtained by Xe clearance were compared with flow values obtained concomitantly by the microsphere technique in 17 cold acclimated rats, at ISBAT blood flows between 0.1 and 6 ml·g−1·min−1. Variations in blood flows were obtained by infusion of noradrenaline at different rates. The blood flow values obtained from the xenon clearance method showed a close correlation to the blood flow values determined with microspheres.Y=0.98.X+0.15 (r=0.96,P〈0.001). The Xe clearance method has the advantages compared to the microsphere technique that it permits continuous monitoring of the blood flow and does not require the sacrifice of the animal.
    Materialart: Digitale Medien
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  • 108
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 326 (1984), S. 248-253 
    ISSN: 1432-1912
    Schlagwort(e): Neonatal capsaicin ; Antinociceptive effects ; Adjuvant arthritis ; Substance P ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Rats were treated with capsaicin (50 mg/kg, SC) either on the second day or on the second and third days of life. A significant attenuation of the responses to noxious stimuli was obtained in the capsaicin treated animals as measured by the hot-plate or paw pressure tests but not by the tail-flick test. Furthermore, neonatal capsaicin produced a significant reduction of response in the formalin test. Capsaicin reduced the reaction latency in rats with adjuvant arthritis as measured by the hot-plate and paw pressure tests, though capsaicin did not alter the overall time course of the response to Freund's adjuvant. Capsaicin also attenuated the weight loss or the decreased ambulatory and rearing behaviour which occurred in the control animals with adjuvant arthritis. It is suggested that neonatal treatment with capsaicin may relieve the responsiveness to longlasting nociceptive stimuli by adjuvant in rats.
    Materialart: Digitale Medien
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  • 109
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 326 (1984), S. 227-232 
    ISSN: 1432-1912
    Schlagwort(e): Pentobarbital ; Benzodiazepine derivatives ; Cerebellar Purkinje cell ; Interposed nucleus cell ; Discharge pattern ; Rabbit ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The discharge of cerebellar neurons was investigated in the rabbit and the rat under the influence of pentobarbital, diazepam or medazepam. In the rabbit, these drugs are known to induce a rhythm ranging between 4 and 25 Hz in the red nucleus (RN) and the cerebellum (Cb). Purkinje cells (P cells) in the intermediate zone of the cerebellar cortex as well as neurons of the interposed nucleus (IPN) were found to discharge with burst patterns fully synchronized with the drug-induced RN rhythm. In contrast, P cells in the medial cerebellar zone responded to these drugs only with changes in their discharge rate. Since P cells of the intermediate longitudinal zone project to the RN mainly via the IPN, the present findings complement our previous results, indicating that the rhythmic electrical activity in the RN is initiated by the cerebellum. The three drugs had similar effects on the activity of cerebellar units in the rabbit and the rat. The investigation also shows that, in spite of the uniform morphological structure of the cerebellar cortex, P cells do not respond uniformly to a given drug: the diversity of findings published on the P cell response to barbiturates or benzodiazepine derivatives may be explained by differences in the recording sites.
    Materialart: Digitale Medien
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  • 110
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 327 (1984), S. 14-17 
    ISSN: 1432-1912
    Schlagwort(e): Bethanechol ; Electromyogram ; Substantia nigra pars reticulata ; Morphine ; Muscular rigidity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Bethanechol chloride (5–25 μg), when injected into the substantia nigra pars reticulata (SNR) of rats, produced muscular rigidity in a dose-dependent way, and in addition, catalepsy and ipsilateral posture. The effects of bethanechol in the dose of 25 μg were prevented by coadministration of 10 μg scopolamine hydrochloride. Injections of 25 μg betanechol or 10 μg scopolamine into the reticulata only slightly affected the muscular rigiditiy produced by 15 mg/kg i.p. morphine hydrochloride. The results suggest that muscarinic cholinergic mechanisms in the substantia nigra pars reticulata, although effective by themselves, affect by expression of at least one striatal functional alteration, the muscular rigidity, in a less effective way than GABAergic or endogenous opioid mechanisms do.
    Materialart: Digitale Medien
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  • 111
    Digitale Medien
    Digitale Medien
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 327 (1984), S. 260-265 
    ISSN: 1432-1912
    Schlagwort(e): Amitriptyline ; Imipramine ; Clomipramine ; Demethylated metabolites ; Free fractions ; Serum ; Equilibrium dialysis ; Gas chromatography ; Binding parameters
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The plasma protein binding of amitriptyline, imipramine, clomipramine, and their primary demethylated metabolites were studied by means of a method combining dialysis and gas chromatography. Equilibrium in dialysis of serum containing amitriptyline and its metabolite nortriptyline was attained in about 0.5 h with the drug dissolved in the serum compartment, and in about 2 h with the drug passing from the buffer to the serum compartment. The calculation of free fractions was influenced by variations with dialysis time in the volumes of serum and buffer. Increase of pH in serum increased the protein binding of the weakly basic drugs studied, and made the Donnan distribution effects more pronounced. At pH 7.4, the Donnan effect was negligible. Binding parameters for the 6 tricyclic antidepressant substances studied were estimated for the binding to α1-acid glycoprotein and for total binding in serum. For α1-acid glycoprotein, the k-values ranged from 1·105 to 8·105 M−1, and for pooled serum from 0.4·105 to 8·105 M−1. The determined number of binding sites on the α1-acid glycoprotein was, on average 0.87 for the 6 substances. In serum, the binding capacity was 2–14 times the concentration of α1-acid glycoprotein.
    Materialart: Digitale Medien
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  • 112
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 373-381 
    ISSN: 1432-0878
    Schlagwort(e): Merkel cell surface ; Quinacrine fluorescence ; Lectins ; Vibrissae ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Surface carbohydrates on the Merkel cell of the outer root sheath (ORS) were investigated in 1to 4-day-old rat vibrissae by use of rhodamine isothiocyanate (RITC)-conjugated lectins. The red fluorescence of RITC provided a convenient assay for lectin binding to the Merkel cell, which is itself identified by its green fluorescence following selective uptake of the dye quinacrine. In monolayers or suspensions of freshly dissociated ORS cells, the Merkel cell showed high affinity for the α-fucose-specific lectin, Ulex europeus agglutinin I (UEA-I), thus revealing a novel feature for a basally located cell. Other high-affinity lectins included concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SBA), and Ricinus communis agglutinin I (RCA-I). In contrast, Dolichos biflorus (DBA), Bandeiraea simplicifolia I and II (BS-I and BS-II), and peanut agglutinin (PNA) virtually excluded the Merkel cell, though PNA-binding sites were unmasked after neuraminidase treatment. Other dispersed ORS cells had varying lectin affinities, and generally binding was inhibited by a competing haptenic sugar. The pattern of lectin binding seen in cryostat and paraffin sections of the vibrissa suggested that the Merkel cells share surface properties with their neighboring basal and/or spinous cells; however, unshared properties are likely to exist since ingrowing mechanosensory nerves recognize the Merkel cells, and not other epidermal cells, as their targets.
    Materialart: Digitale Medien
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  • 113
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 711-715 
    ISSN: 1432-0878
    Schlagwort(e): Gastric antral mucosa ; Caerulein ; Gastrointestinal hormones ; Cholecystokinin ; Trophic effect ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The growth-promoting effect of caerulein on antral gastric mucosa was explored using Wistar rats. Implanted osmotic minipumps were used to administer submaximal doses of either caerulein or saline to normal rats for up to 4 days. In one group, reflux of bile and pancreatic juice into the stomach was avoided by previous surgical diversion of the distal common bile duct to the jejunum. DNA synthetic and mitotic activity in the antrum epithelium were estimated by 3H-thymidine pulse labelling and autoradiography during the administration of the peptide. The rate of cell migration was determined in animals killed 1, 2 and 3 days after the 3H-thymidine pulse. Administration of caerulein to normal rats provoked significant increases in both labelling and mitotic indices, and a significant acceleration of the upward cell migration in the glandular tubes. In the animals with distal diversion of bile and pancreatic secretions both labelling and mitotic indices were also increased over control values under the effect of the peptide. These data indicate that administration of caerulein stimulates cell proliferation in the antral gastric mucosa. This effect cannot be explained through increased reflux of pancreaticobiliary secretions in the stomach.
    Materialart: Digitale Medien
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  • 114
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 699-709 
    ISSN: 1432-0878
    Schlagwort(e): Testis ; Spermatogenic cycle ; Sertoli cell ; Lipid ; Morphometry ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The volume and surface area of lipid inclusions often present in the cytoplasm of rat Sertoli cells was measured directly from semi-thin sections of perfusion-fixed testicular tissues using an image analyser linked to a light microscope. Sertoli cell nuclei were used as a reference for comparing any variations in the measured parameters of lipid inclusions during the rat spermatogenic cycle. Volume density of Sertoli cell lipid inclusions was assessed by morphometric analysis of Sertoli cells photographically reconstructed from electron micrographs. Maximum lipid content in Sertoli cells occurred during stages IX–XIV of the spermatogenic cycle, then declined at stages I–III and remained low from stages IV–VIII. The persistence and increase in number of many large Sertoli cell lipid inclusions beyond the stage where spermatid residual bodies are phagocytosed within the Sertoli cells (stage IX) suggests that the synthesis and lipolysis of Sertoli cell lipid inclusions represents an intrinsic functional cycle of the Sertoli cells. Stage-dependent variations in the lipid content of rat Sertoli cells offers morphological evidence that the metabolic duties of the Sertoli cells are synchronised with the spermatogenic cycle to provide local coordination of the proliferation and maturation of the germ cells.
    Materialart: Digitale Medien
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  • 115
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 717-724 
    ISSN: 1432-0878
    Schlagwort(e): Ovary ; Ovarian follicle ; Atresia ; Immunoregulation ; Immune tolerance ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Thy-1+ cells, producing Thy-1+ material, have been demonstrated by the indirect immunoperoxidase technique in the theca of growing ovarian follicles of the rat. OX-2 antigen, known as the minor glycoprotein of rat thymocytes, was detected in granulosa cells of non-growing follicles. Ia+ cells of dendritic type and/or activated macrophages were identified in the granulosa of advanced degenerating follicles, and remnants of the zona pellucida exhibited immunoglobulins. In some ovaries immunoglobulins were also bound to the zona pellucida of oocytes of early degenerating antral follicles. Medium-sized antral follicles with degenerating granulosa were occasionally invaded by cells carrying antigens of cytotoxic T lymphocytes or other T lymphocyte subsets, while degenerating large antral follicles were sometimes invaded by cells exhibiting antigen of cells with natural killer function (but not antigens of T lymphocytes). Granulosa cells of some degenerating antral follicles exhibited class-I antigens derived from the major histocompatibility complex. We suggest that cell-mediated control mechanisms of antigen expression and metabolism of tissue cells during their differentiation and degeneration should be considered in addition to the well-documented hormonal dependence of some tissues.
    Materialart: Digitale Medien
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  • 116
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 237 (1984), S. 245-252 
    ISSN: 1432-0878
    Schlagwort(e): Pineal organ ; Interstitial cells ; Astrocytes ; Immunocytochemistry ; Rat ; Mouse
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Antigenic markers characteristic of astrocytes and their differentiative states (i.e., glial fibrillary acidic protein (GFAP), vimentin, and M1 and C1 antigens) were investigated in the pineal gland of mouse and rat using double immunolabeling techniques. In both species the socalled interstitial cells as characterized by TEM were shown to be astrocytes, since they expressed vimentin, but neither fibronectin (a marker for fibroblasts and endothelial cells) nor the neuron-specific L1 antigen or tetanus toxin receptors. Subpopulations of vimentin-positive pineal astrocytes were also GFAP- and C1- antigen-positive. M1- antigenpositive cells were not detected. It is concluded that a considerable proportion of interstitial cells in the pineal gland of rat and mouse are immature astrocytes which, in contrast to other parts of the central nervous system, persist into adulthood.
    Materialart: Digitale Medien
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  • 117
    ISSN: 1432-0878
    Schlagwort(e): Thyroid gland, fetal ; Cytoskeleton ; Cytocha lasin B ; Vinblastine ; Colchicine ; Follicular development (thyroid) ; Tissue culture ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Thyrotropic hormone (TSH) or cAMP accelerate the formation of follicular cavities in the explanted thyroid gland of the 15-day-old rat fetus. Cytochalasin B or vinblastine and nocodazole or colchicine, which disorganize microfilamental and microtubular structures respectively, inhibit or completely block in vitro-induced folliculogenesis. Exposure of the thyroid tissue to lumicolchicine, a structural isomer of colchicine deprived of antimicrotubular activity, does not inhibit the activation of folliculogenesis induced by TSH. These results are strong evidence for the supposition that microfilaments and microtubules are involved in the TSH-stimulated mechanisms resulting in thyroid folliculogenesis. Folliculogenesis requires the integrity of both microfilaments and microtubules.
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  • 118
    ISSN: 1432-0878
    Schlagwort(e): CRF-neurons ; Hypothalamus ; Development, ontogenetic ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Appearance of immunoreactive corticotropin-releasing factor (CRF)-containing neurons was studied in developing hypothalamus of the rat by use of antisera against rat- and ovine CRF. These neurons were first recognized in the lateral and paraventricular nuclei on days 15.5 and 16.5 of gestation, respectively, when antiserum against rat CRF was employed. Antiserum against ovine CRF revealed the cells two days later exclusively in the latter nucleus. In both nuclei, the neurons increased in number with development. The neurons in the paraventricular nucleus appeared to project their immunoreactive processes to the median eminence via the periventricular and lateral pathways. In the median eminence, the immunoreaction with antiserum to rat CRF was first recognized in its anterior portion in the form of dots on day 16.5 of gestation but as beaded fibers in the external layer on day 17.5; these structures increased in amount with development in rostro-caudal direction. Although antiserum to ovine CRF was less potent in immunostainability than antiserum to rat CRF, it also revealed the beaded fibers in the median eminence on day 17.5 of gestation. Since evidence is available that the paraventricular nucleus is involved in corticotropin release, it is concluded that, in rats, the hypothalamic regulatory mechanism controlling the release of corticotropin initially appears on days 16.5–17.5 of gestation.
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  • 119
    ISSN: 1432-0878
    Schlagwort(e): Caldesmon ; Actin ; Immunocytochemistry ; Small intestine ; Smooth muscle ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of caldesmon (a calmodulin-binding, F-actin-interacting protein) (Sobue et al. 1982) and of actin was studied in the rat's small intestine by means of light-microscopic immunocytochemistry. Positive immunostaining for caldesmon was seen in smooth muscle cells of the intestinal wall, and of blood vessels, and in the apical portion of the absorptive epithelial cells. The immunoreactivity in goblet cells was difficult to recognize. The positive reaction to immunostaining for actin showed almost the same pattern as that for caldesmon. These results suggest that this calmodulin-binding protein may play an important role in the control of actin-myosin interaction in smooth muscle cells and in non-muscle cells.
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  • 120
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 235 (1984), S. 433-438 
    ISSN: 1432-0878
    Schlagwort(e): Mammary gland ; Ferritin-concanavalin A ; Concanavalin A ; Endocytosis ; Membrane reuse ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Ferritin-concanavalin A (Fer-Con A) was used to label the apical plasma membrane of the lactating cell to determine whether membrane internalization takes place. Rat glands were infused in vivo via the teat with 0.2 mg of Fer-Con A in 0.2 ml tris buffer (pH 7.0) containing 0.1% trypan blue, the latter acting as a marker of the infusate. Tissues were obtained from separate animals 5, 10 and 60 min postinfusion. Fer-Con A was seen in alveolar lumina bound to the outer surfaces of apical plasma membrane, microvilli and milk fat globules. It was observed within lactating cells on the inner membrane surfaces of endocytotic vesicles, Golgi cisternae, and secretory vesicles containing casein micelles, and in multivesicular bodies and lysosomes. Internalization of the ferritin-lectin conjugate into casein-containing secretory vesicles was detectable in the 5-min postinfusion tissue. Lysosomes were the only structures in control tissue that contained particles bearing some resemblance to Fer-Con A. The data provide evidence that apical plasma membrane is internalized and distributed to a number of intracellular compartments.
    Materialart: Digitale Medien
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  • 121
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 235 (1984), S. 449-452 
    ISSN: 1432-0878
    Schlagwort(e): Suprachiasmatic nucleus ; Morphometry ; Synapses ; Sexual dimorphism ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The suprachiasmatic nucleus (SCN) of male rats was estimated to contain 16×106 synaptic appositions (unilaterally) or 250×106 appositions in 1 mm3 tissue of the nucleus with an average of 1404 appositions per neuron. There are significantly fewer synaptic appositions in the suprachiasmatic nucleus of female rats (15×106 per SCN or 236×106 in 1 mm3 tissue of SCN with 1264 appositions per neuron on an average). Additionally, numbers of various types of synapses (axo-somatic, invaginated, dendrodendritic and optic) are estimated.
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  • 122
    ISSN: 1432-0878
    Schlagwort(e): Monosodium-1-glutamate ; Neuropathology ; Rat ; Superior colliculus ; Toxicology
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Systemic administration of monosodium-1-gluta-mate by single injections of 4 mg/g body weight in infant rats (2–10 days of age) results in acute swelling of cytoplasm and nuclear pyknosis of neurons in the stratum zonale and stratum griseum superficiale of the superior colliculus. Multiple daily doses of 4 mg/g body weight monosodium-1-glutamate result in an almost complete loss of neurons in these two superficial layers. The deeper layers appear not to be affected. No pathological effects were observed in the lateral geniculate body or pretectal complex. Light-and electron-microscopic studies reveal that the optic nerves are remarkably shrunken and many myelinated as well as unmyelinated axons are lost. Injection of 3Hproline into the vitreous body of one eye results in limited transport to the suprachiasmatic nucleus, lateral geniculate body and to lateral portions of the superior colliculus. The small percentage of intact axons in the optic nerve, as well as the limited proline transport from the eye, suggest that administration of monosodium-1-glutamate leaves intact some optic fibers, a portion of which belongs to the retinohypothalamic tract.
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  • 123
    ISSN: 1432-0878
    Schlagwort(e): Exocrine pancreas ; Calcium pool ; Calcium release ; Electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In an attempt to identify a cellular Ca2+-pool, from which calcium is released when secretagogues are applied, tissue fragments of the rat exocrine pancreas were incubated and fixed with glutaraldehyde in the presence of calcium. By means of this procedure electron-dense deposits were found on plasma membranes. X-ray microanalysis showed that these deposits contain calcium. Stimulation of tissue fragments with the use of the secretagogues carbachol or cholecystokinin reduced the number of deposits by about 80%. When the antagonist atropine was applied after carbachol stimulation, deposits reappeared on cell membranes, which then disappeared again after a second stimulation with cholecystokinin. In the presence of procaine, carbachol was inhibited and only slightly reduced the Ca2+-deposits on the plasma membranes. These results suggest that a calcium pool, from which calcium is released to induce enzyme secretion on stimulation, is located in the cell membrane
    Materialart: Digitale Medien
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  • 124
    ISSN: 1432-0878
    Schlagwort(e): Somatostatin ; Ontogenesis ; Electron-microscopic immunohistochemistry ; Median eminence ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The development of immunoreactive (ir) somatostatin-containing nerve terminals in the rat median eminence (ME) has been examined electron-microscopically. Nerve fibers containing ir particles scattered throughout the axoplasm are first seen in the external layer of the ME on day 18.5 of gestation, and, on day 21.5 appear to terminate on the basement membrane of the perivascular space of the portal vessels. After birth, the fiber terminals contain several membrane-limited granules, which are labeled with ir PAP particles. Ultrathin, Epon-embedded sections of ME, treated by the protein A gold-labeling method for somatostatin, demonstrate positively labeled granules in the nerve fibers in the postnatal ME, but in the prenatal tissue, no specific gold-labeling is found. These findings show that, in the external layer of the ME, somatostatin storing occurs in the granules in the axonal terminals after birth.
    Materialart: Digitale Medien
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  • 125
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 491-493 
    ISSN: 1432-0878
    Schlagwort(e): Brain vessels ; Basal lamina ; Pericytes ; Endothelial cells ; Glial cells ; Argyrophilic staining ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Vibratome sections obtained from perfusion-fixed rat brains were stained by means of silver impregnation and physical development according to Gailyas (1970). Small pieces of the cerebral cortex were postfixed with buffered osmium tetroxide solution and processed for electron microscopy to examine the localization of the silver deposit at the cellular level. The cell surfaces of pericytes and smooth muscle cells were completely outlined by silver grains. Endothelial cells and perivascular astrocytes, however, showed an asymmetric distribution of the silver deposit, i.e., the deposit was restricted to the abluminal endothelial surface and to the astrocytic membrane adjacent to the vessel wall, respectively. The method allowed a clear-cut distinction between perikarya of endothelial cells and pericytes as well as glial cells in perivascular position, even at the light-microscopic level.
    Materialart: Digitale Medien
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  • 126
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 249-255 
    ISSN: 1432-0878
    Schlagwort(e): Oocyte ; Nucleolus ; Silver staining ; Electron microscopy ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The nucleoli of dictyate-stage growing oocytes in rat ovaries were examined both with routine electron microscopy and electron microscopy after silver nitrate and ammoniacal silver nitrate (Ag-AS) staining. The nucleoli of the unilaminar follicular oocytes consist of twisted strands of dense fibrillar components, aggregates of granular components, and small fibrillar centers. After Ag-AS staining, silver grains are numerous on the dense fibrillar strands, fewer on the fibrillar centers, and very sporadic on the granular aggregates. The same stainability of three nucleolar components with the Ag-AS method was also confirmed in the nucleoli segregated by actinomycin D. During the transition of growing oocytes from bilaminar to plurilaminar follicle stage, the nucleolar dense fibrillar strands gradually conglomerate and are transformed into large and compact spherules. The stainability of dense fibrillar components with the Ag-AS method was lost along with this nucleolar transformation. These results may provide some new clues on the functional significance of AgAS-positive proteins in the nucleoli.
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  • 127
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 237 (1984), S. 103-109 
    ISSN: 1432-0878
    Schlagwort(e): Synapses ; Synaptogenesis ; Development fetal ; Olfactory cortex ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Electron microscopy was used to study synaptogenesis in prepyriform cortex of fetal rat pups during early stages of synapse formation. Of special interest is the frequent occurrence of unapposed, developing synaptic specializations in axon and growth cone profiles. The location and morphology of the unapposed specializations suggests that thay are presynaptic in nature. These presumably immature presynaptic specializations are found in the lateral olfactory tract and subjacent cortex. Intermediate forms between uncontacted presynaptic specializations and definitive synapses suggest a synaptogenic sequence in which initial development of an immature presynaptic specialization begins without apposition of a postsynaptic element at that location. This implies that initiation of presynaptic development is not dependent upon postsynaptic contact and also raises the question of whether synaptic contacts could be established via presynaptic induction of postsynaptic formation.
    Materialart: Digitale Medien
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  • 128
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 237 (1984), S. 185-186 
    ISSN: 1432-0878
    Schlagwort(e): Gap junction ; Cytoskeleton ; Heart ; Ultrarapid freezing ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Using ultrarapid-freezing techniques and freezefracture electron microscopy, we report here a close association between cardiac gap junctions and specialized membrane domains containing regularly-spaced furrows. These specialized furrowed domains are observed only during periods of gap junction re-organisation (i.e., connexon redistribution) and may reflect the presence of underlying cytoskeletal elements controlling the position of connexons in the membrane.
    Materialart: Digitale Medien
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  • 129
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 237 (1984), S. 371-373 
    ISSN: 1432-0878
    Schlagwort(e): Endothelium ; Transport, intracellular ; Transport vesicles, channels ; Micropinocytosis ; Capillaries ; Endometrium ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Three types of transendothelial channels are described in the endothelium of blood capillaries in the endometrium of the rat. It is postulated that they may function as pores draining interstitial fluid to the venous blood.
    Materialart: Digitale Medien
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  • 130
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 237 (1984), S. 375-377 
    ISSN: 1432-0878
    Schlagwort(e): Thyroid ; Immunocytochemistry ; Caldesmon ; Actin ; Endocytosis ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of caldesmon (a calmodulin-binding, F-actin interacting protein; Sobue et al. 1982) and actin was studied in the rat thyroid gland by means of light-microscopic immunocytochemistry, and the fine-structural distribution of actin filaments was examined by use of heavy meromyosin (HMM). Caldesmon and actin were demonstrated in the apical cytoplasm of almost all the follicle epithelial cells in normal as well as TSH-treated animals. Immunoreactivities for both caldesmon and actin showed almost the same pattern in localization. The smooth muscle cells of the blood vessels were also positive for caldesmon and actin. By electron microscopy, numerous actin filaments decorated by HMM and running perpendicularly or randomly to the apical surface were recognized in the apical cytoplasm of the follicle epithelial cell. These results suggest that caldesmon and actin, in conjugation with calmodulin, play a role in the regulation of cellular activity such as exocytosis and endocytosis in the apical portion of the follicle epithelial cell.
    Materialart: Digitale Medien
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  • 131
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 235 (1984), S. 187-194 
    ISSN: 1432-0878
    Schlagwort(e): Golgi apparatus ; Monensin ; Small intestine ; Cytochemistry ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effect of short-time treatment with the ionophore monensin, administered intraluminally at concentrations of 5 and 10 μM, was studied on the Golgi apparatus of absorptive cells in the small intestine of the rat. At 2–3 min after treatment most of the Golgi stacks exhibited dilated cisternae. At 4–5 min stacked cisternae were absent; they were replaced by groups of smooth-surfaced vacuoles. Dilatation and vacuolization occurred in the entire stacks without preferential effect on any particular Golgi subcompartment. Monensin did not influence the cytochemical Golgi reaction of thiamine pyrophosphatase and acid phosphatase. The characteristic staining pattern of these two enzymes in all Golgi cisternae of absorptive cells in the proximal small intestine, and the reactivity restricted to trans cisternae in distal segments of the small intestine, were unchanged after treatment with monensin. In the distal small intestine, the cytochemical pattern allowed the monensin-induced vacuoles to be attributed to the former cisor trans-Golgi face. Further, the cytochemical results demonstrate that vacuolization is not restricted to the stacked cisternae, but includes the trans-most cisterna. The latter, usually located at some distance from the Golgi stacks, has been defined as belonging to the GERL system in several types of cells. The clear response to monensin, an agent that selectively affects the Golgi apparatus, indicates common properties between trans-most and stacked Golgi cisternae.
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  • 132
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 235 (1984), S. 485-489 
    ISSN: 1432-0878
    Schlagwort(e): Ventromedial nucleus ; Hypothalamus ; Ultra-structure ; Nucleoli ; Estrogen effects ; Chromatin ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Estrogen is accumulated from the blood by nerve cells in the ventromedial nucleus of the hypothalamus and can facilitate female reproductive behavior by acting on this region of the brain. This cell group was examined in ovariectomized female rats, given estrogen or control treatment, by use of light and electron microscopy. A significantly greater portion of the nerve cells in the estrogen-treated animals had protuberances on their nucleolar surfaces, apparent under the light microscope. The fine structure of such protuberances included dense, aggregated material, which is shown to contain DNA by the sodium tungstate staining technique. Because increased numbers of such protuberances were found in nuclei of cells of the experimental group where previous studies demonstrated a significant increase in ultrastructural signs of biosynthetic activity, they may be associated with increased RNA synthesis. Thus, they could indicate, ultrastructurally, increased synthetic rates for RNA in nerve cells through which estrogen promotes reproductive behavior.
    Materialart: Digitale Medien
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  • 133
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 235 (1984), S. 669-673 
    ISSN: 1432-0878
    Schlagwort(e): Liver-cell heterogeneity ; Hepatic venous branches ; Karyometry ; Binucleate cells ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In untreated adult male albino rats nuclear volume and the percentage of binucleate cells were determined in the first layer of hepatocytes adjacent to hepatic venous branches of varying diameters (〈40 μm, 40 μm–80 μm, 80 μm–120μm, 120 μm–160 μm, 〉160 μm), and in the third and fourth layer of hepatocytes in the remainder of the perivenous parenchyma. In the first layer of hepatocytes adjacent to the vascular structures means of nuclear volume are significantly lower and percentage of binucleate cells significantly higher than in the cells of the remainder of the perivenous parenchyma. Within each area measured distribution curves of nuclear volume classes were homogeneous but showed heterogeneity in comparison with each other. The morphometric data presented in this study strongly support the opinion of the heterogeneity of liver cells in the perivenous zone, as previously postulated on the basis of histochemical investigations.
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  • 134
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 305-315 
    ISSN: 1432-0878
    Schlagwort(e): Hepatocytes ; Rat ; Liver ; Circadian rhythm ; Morphometry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Subcellular structures of hepatocytes in periportal and perivenous zones were examined during 24 h. The volume, surface and numerical profile densities of cytoplasmic organelles were analysed morphometrically. Most subcellular structures in periportal and perivenous hepatocytes were subject to strong circadian variations. In hepatocytes from both zones, the volume densities of smooth endoplasmic reticulum (sER), mitochondria, lysosomes, peroxisomes, polysomes and lipid droplets demonstrated peak values at 16.00 h, 20.00 h or 00.00 h; trough values were at 04.00 h, 08.00 h, or 12.00 h, except for peroxisomes (16.00 h). However, the volume densities of glycogen granules and rough endoplasmic reticulum (rER) in periportal and perivenous hepatocytes exhibited maximal values at 04.00 h, 08.00 h or 12.00 h and minimal values at 20.00 h. The surface densities of sER, mitochondria, lysosomes and peroxisomes, and the numerical profile densities of mitochondria, lysosomes and peroxisomes in periportal and perivenous hepatocytes showed similar trends. These events suggest that membranes of the rER show a partial correlation with the sER, mitochondrial and lysosomal membranes during the 24-h span. This may involve the interaction between ribosomes and rER. Almost all cytoplasmic organelles examined displayed significant differences between periportal and perivenous hepatocytes, morphometrically and in fine structure, indicating that the morphofunctional variability of hepatocytes differs depending on the location in the liver acinus.
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  • 135
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 321-325 
    ISSN: 1432-0878
    Schlagwort(e): Triiodothyronine ; Radioautography ; Mitochondria ; Liver ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary To assess the distribution of the thyroid hormone triiodothyronine (T3) within intact living cells, freshly prepared dispersed rat hepatocytes were incubated with [125I]-T3 for periods of 5 min and 30 min. Lightand electron-microscopic (EM) radioautography was carried out to determine the distribution of grains over the isolated cells. Both procedures showed the grains distributed almost entirely over the cytoplasmic matrix rather than the nucleus. Grain counts under the EM were compared with expectation based on established quantitative methods. Only the mitochondria showed obvious and statistically significant grain counts, whereas the nucleus failed to accumulate grains in excess of expectations by chance alone based on area. The findings support the existence of mitochondrial binding of T3, presumably a prerequisite for its action in direct stimulation of the mitochondria.
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  • 136
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 351-355 
    ISSN: 1432-0878
    Schlagwort(e): Lymph node ; Steroids ; Macrophages ; Intercellular junctions ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Intercellular junctions were often found between macrophages in sinuses of regional lymph nodes of the rat after injection of large doses of cholesterol, cortisone acetate, and estrone at the footpad. They were identified by subplasmalemmal densities, 20–50 nm in width, beneath the plasma membranes of apposed macrophages. No distinct filamentous structures were visible in those dense regions. Electron-dense amorphous materials are lined up at the center of the intercellular space in the junctional regions. Some macrophages form clusters with intercellular junctions. No significant difference in the effect of cholesterol, cortisone acetate, and estrone on the number of intercellular junctions betwene macrophages was found.
    Materialart: Digitale Medien
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  • 137
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 171-180 
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Ultrastructure ; Supraoptic nucleus ; Neuropil ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The neuropil located ventral to the SON was investigated by the use of immunoperoxidase staining for neurophysins, oxytocin and vasopressin, and electron miroscopy. The study was performed in six groups of rats: 1) control; 2) infusion of isotonic saline into the CSF; 3) infusion of hypertonic saline into the CSF; 4) drinking hypertonic saline for 4 days; 5) same as group 4 but injection of colchicine into the CSF on second day of dehydration; 6) salt loading for 3 months. In the control rats the ventral neuropil contained a few immunoreactive processes, the general morphology of which was completely different from that of the neurosecretory axons emerging from the SON at its dorsal aspect. In rats of groups 3 to 6 the ventral processes (VP) became loaded with neurosecretory granules, whereas the perikarya and axons were depleted. Based on their general morphology and reactivity pattern it is suggested that the VP are dendrites. Most of these “dendrites” were embedded in a glial cushion formed by the processes of a particular type of marginal glia. Some of these “dendrites” enveloped an arteriole penetrating the optic tract. All VP were rich in synaptic contacts. The possibility that the VP of neurosecretory cells may be functionally related to the subarachnoid CSF and the arteriolar blood flow is discussed.
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  • 138
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 236 (1984), S. 561-566 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland, pars intermedia ; Peptide hormones ; Dopamine ; Corticotropin-releasing hormone ; 6-Hydroxydopamine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary When rats were injected with 6-hydroxydopamine the catecholaminergic nerve terminals in their intermediate lobes exhibited distinct signs of degeneration. Morphometric examination of the Golgi apparatus in cells of the intermediate lobe of these rats showed significant enlargement of Golgi cisternae. The release of adrenocorticotropin, β-endorphin/lipotropin and α-melanotropin from intermediate-lobe cells in vitro was measured by radioimmunoassay. The high basal peptide release was inhibited by dopamine and stimulated by methyl-isobutyl-xanthine. In contrast, γ-aminobutyric acid, serotonin, histamine and noradrenaline, or corticotropin-releasing hormone, rat hypothalamic extract and vasopressin had no or only very weak effects. These observations indicate that the synthetic apparatus of intermediate-lobe cells is constantly depressed by dopaminergic nerves. We were not able to stimulate peptide release from intermediate-lobe cells by use of the abovementioned endogenous agents.
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  • 139
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 237 (1984), S. 169-179 
    ISSN: 1432-0878
    Schlagwort(e): Foetal pancreas ; β Cells ; Insulin ; Fasting mothers ; Morphometry ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary After maternal fasting for 72 h the pancreatic β cells of 18-day-old foetal rats show a conspicuous enrichment in secretory material, with an increase of pancreatic insulin concentration and a marked development of the rough endoplasmic reticulum and the Golgi apparatus. The morphometric analysis shows that the intracytoplasmic migration of the secretory granules is inhibited, principally inside the cell web. Consequently the number of secretory granules fused with plasma membrane decreases and this is associated with a decreased foetal plasma insulin. The difference in the ultrastructural aspect of the β cells of foetuses from fasting mothers and of foetuses from fed mothers is less conspicuous at 19 days of gestation and progressively disappears at 20 and 21 days. The modifications in ultrastructural aspect and in functional state are discussed.
    Materialart: Digitale Medien
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  • 140
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 238 (1984), S. 81-85 
    ISSN: 1432-0878
    Schlagwort(e): Retina ; Ibotenic acid ; Toxicity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary After 2 h intraocular injections of 19 and 190 nmoles ibotenic acid in the rat retina produced an intensive vacuolization of the inner plexiform layer and cellular alterations, in the inner nuclear layer and ganglion cell layer. These alterations consisted of either cytoplasmic swelling accompanied by clumping of the nuclear chromatin or darkening of the cytoplasm along with nuclear condensation. A week later the retinas were thinner than the controls due to the disappearance of the affected cells. Pre-treatment with diazepam prevents the morphological alterations induced by 19 nmoles ibotenic acid; mainly the swelling, which was completely prevented, while the darkening was reduced drastically, although some vacuolization of the inner plexiform layer is still present.
    Materialart: Digitale Medien
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  • 141
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 238 (1984), S. 159-163 
    ISSN: 1432-0878
    Schlagwort(e): Ovary ; Rat ; Cell division ; Luteinizing hormone
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effect of an LH pulse on the rate at which 3H-thymidine is incorporated into cultured ovaries of metestrous rats was studied. In comparison to ovaries cultured with tonic LH, an LH pulse (1) “rescued” follicles from atresia, (2) induced thecal cell proliferation, and (3) increased the rate at which granulosa cells enter mitosis. It is concluded that LH pulses increase follicular growth by first triggering thecal cell proliferation and then inducing mitotic divisions within the granulosa cells of both atretic and non-atretic follicles.
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  • 142
    ISSN: 1432-0878
    Schlagwort(e): Choroid plexus ; Immunoglobulin G ; Permeability ; Anti-HRP-IgG ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The localization of autologous antiperoxidase immunoglobulin G (IgG) was studied in the choroid plexus of Lewis rats immunized against horseradish peroxidase (HRP). This experiment was performed to study the permeability of the choroid plexus to intravascular IgG. It was shown that autologous IgG was present in the extravascular spaces. The transendothelial transfer appeared to occur mainly via the fenestrations and some interendothelial junctions. No transfer of IgG at the level of epithelial cells toward the cerebrospinal fluid was demonstrated. Interstitial spaces in contact with the connective-tissue cells of the choroid stroma were strongly labeled. The significance of these spaces remains hypothetical and raises the question of the fate of IgG from the interstitial space.
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  • 143
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 238 (1984), S. 191-195 
    ISSN: 1432-0878
    Schlagwort(e): Glial fibrillary acidic protein (GFAP) ; Pituicytes, neonatal ; Development, ontogenetic ; Immunofluorescence ; Organ culture ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The appearance and intracellular localisation of glial fibrillary acidic protein (GFAP) in pituicytes in neural lobe cultures of newborn rats aged 7 to 30 days were investigated by use of the indirect immunofluorescence method. GFAP-immunoreactive cells were observed mostly in the outgrowth zone. GFAP was localised in the perikaryal cytoplasm as well as in pituicyte processes. GFAP-positive pituicytes showed considerable morphological polymorphism. The presence of GFAP — astrocytic marker — in pituicytes in vitro and the evident morphological similarity to cultured astrocytes suggest the astroglial character of these cells.
    Materialart: Digitale Medien
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  • 144
    ISSN: 1432-0878
    Schlagwort(e): Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) ; New cytochemical method ; Retina ; Rods, outer segments ; Light perception ; 5′GMPase ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cyclic guanosine monophosphate-phosphodiesterase (cGMP-PDEase) activity was studied histo- and cytochemically in the retinal rods of the rat with the use of a newly developed technique. Intense activity of cGMP-PDEase was evenly distributed over the outer segments of the rods. Reaction product was observed on the plasmalemma and on the disk membranes of the outer segments. A weak reaction product occurred also on the plasmalemma of the inner segments; however, no precipitate was found in the perinuclear and synaptic portions of the rod cells. The enzyme activity was strongly inhibited by 2 mM theophilline and by 2 mM 3-isobutyl-1-methylxanthine (IBMX). To confirm the specificity of this new cGMP-PDEase method, the localization of 5′nucleotidase (5′GMPase) was also studied. In contrast to the activity of cGMP-PDEase, the activity of 5′GMPase was distributed on the plasma membrane of the photoreceptor cells extending over a wide range from the synaptic endings in the outer plexiform layer to the tip of the outer segments.
    Materialart: Digitale Medien
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  • 145
    ISSN: 1432-0878
    Schlagwort(e): S-100 ; Müller cell ; Astrocyte ; Development ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The rat retina was studied by immunohistochemistry with antibody to S-100 protein during the first three postnatal weeks. Immunoreactive astrocytes are first detected subjacent to the inner limiting membrane close to the optic disc. They gradually increase in number and spread toward the ora serrata along the inner surface of the retina as the development proceeds. S-100-immunostained Müller cells are first identified on the 12th postnatal day although their immunoreactivity is much weaker than that of astrocytes at the same stage. This differential intensity of the immunoreactivity of the two cell types facilitates observation of the entire shape of the astrocyte. This characteristic reveals that cellular investments of blood vessels in the inner retina are formed by astrocytic processes whereas those in the outer plexiform layer are derived from processes of Müller cells. The cellular investment becomes complete by the 18th postnatal day.
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  • 146
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 238 (1984), S. 559-564 
    ISSN: 1432-0878
    Schlagwort(e): Adrenal cortex ; Macrophages ; Ovariectomy ; Rat ; Estradiol administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Macrophages of the adrenal cortex were studied in normal male and female, ovariectomized and estradiol-injected rats. In normal male rats few macrophages with numerous granules were observed in the zona fasciculatazona reticularis border, and in the zona reticularis. Granules, identified as lysosomes, were limited by a single membrane with a heterogeneous matrix; they exhibited acid phosphatase- and aminotriazole-resistant peroxidatic activities. A larger number of macrophages had identical distributions in normal female rats. In ovariectomized and estradiol-injected rats the number and distribution of adrenal macrophages were similar to those in normal females; however, in spayed animals the number of these cells in the zona reticularis was higher than in the other experimental groups. Lysosomes in macrophages of treated animals were more numerous and their contents more complex than in normal male animals. These results indicate that the adrenal macrophage system is stimulated in experimental conditions involving high levels of circulating estrogens.
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  • 147
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 238 (1984), S. 297-305 
    ISSN: 1432-0878
    Schlagwort(e): Sympathetic ganglion ; Development, ontogenetic ; Corticosteroid treatment ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Hydrocortisone injections into rats on postnatal days 3–9 caused an increase in the number of small granulecontaining cells in the superior cervical ganglia. These cells, corresponding to the small, intensely fluorescent cells, showed an extensive rough endoplasmic reticulum, a large Golgi apparatus and a very large number of granular vesicles. In addition to the granular vesicles, 70–160 nm in diameter, in which the dense core filled most of the vesicle, most cells of the hydrocortisone-injected rats contained also larger granular vesicles, up to 350 nm in diameter, in which the dense core was eccentrically located. A minority of the cells contained only granular vesicles 70–100 nm in diameter, which was the only type seen in the saline-treated control rats. Thirty days after discontinuation of the hydrocortisone treatment, most of the cells with large granular vesicles had disappeared, and only two profiles of such cells were seen on day 40. The other small cells contained only granular vesicles 70–160 nm in diameter, and these cells could not be distinguished from the small granule-containing cells of 40-day-old control rats treated early postnatally with saline. Hydrocortisone treatment, first on days 3–9 and subsequently on days 40–46, caused reappearance of the small granule-containing cells with large granular vesicles up to 350 nm in diameter, the dense core of which was eccentrically located. Hydrocortisone treatment on days 40–46 only was not followed by appearance of such cells in rats treated with saline on days 3–9.
    Materialart: Digitale Medien
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  • 148
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 238 (1984), S. 459-474 
    ISSN: 1432-0878
    Schlagwort(e): Meningeal compartment ; Perivascular space ; Brain intercellular compartment ; Cerebral cortex ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The intercellular clefts of the brain and the leptomeninges, and the perivascular spaces were studied with reference to the results obtained in a previous study (Krisch et al. 1983). The spatial relationships of these compartments were analyzed at the electron-microscopic level. Horse-radish peroxidase (HRP) was injected into the brain or into the contralateral ventricle. The pattern of distribution of HRP depends on the boundary situation in the individual compartments. The inner and outer pial layers accompany the vessels intruding into the brain. In the Virchow-Robin space the pial funnel obliterates within a short distance. The inner arachnoid layer is continuous with the outer arachnoid layer when it covers the vessels traversing the meningeal space. The perivascular compartment is not in communication with the arachnoid space; moreover, the pial funnel within the Virchow-Robin space is sealed off against the arachnoid space. Thus, blood vessels traversing the meningeal spaces and subsequently penetrating the brain surface are exposed to the common intercellular compartment represented by the intercellular clefts of the brain and the leptomeninges; this compartment does not communicate with the other compartments. The cerebrospinal fluid located in this intercellular compartment is preferentially drained into the upper cervical lymph nodes.
    Materialart: Digitale Medien
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  • 149
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 238 (1984), S. 635-642 
    ISSN: 1432-0878
    Schlagwort(e): Liver ; Endothelium ; Kupffer cells ; Peroxidase ; Cytochemistry ; Ultrastructure ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rat liver fixed by perfusion with low glutaraldehyde concentrations was incubated in diaminobenzidine-containing medium to stain for peroxidase. Endogenous peroxidatic activity was found not only in Kupffer cells but also in the endothelial cells lining the sinusoids and central veins. The reaction product was localized in the nuclear envelope and endoplasmic reticulum. The peroxidatic activity in endothelial cells showed a concentration-dependent sensitivity to glutaraldehyde: in liver samples fixed with 0.25% glutaraldehyde, approx. 23% of the sinusoidal endothelial cells and 65% of central vein endothelium were peroxidase-positive; with 0.5% glutaraldehyde, only approx. 8% of the sinusoidal endothelial cells contained detectable amounts of the reaction product; with 1.5% glutaraldehyde all endothelial cells were consistently peroxidase-negative. No peroxidatic activity could be found in liver endothelial cells following isolation by centrifugal elutriation. Endothelial cell peroxidase may possibly be involved in defense responses of liver and/or, as a part of prostaglandin synthase system, in prostanoid production.
    Materialart: Digitale Medien
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  • 150
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of C2−C16 dicarboxylic acids ; Dicarboxylic acid analysis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary C2−C16 dicarboxylic acids were esterified in aqueous solution in the presence of sulfuric acid. Esterification in water/n-butanol mixtures with mole ratios between 0.02 and 2.53 can be utilized for the quantitative determination of the dicarboxylic acids by gas chromatography. The presence of water does not interfere at water/n-butanol mole ratios below 0.27. For mole ratios above 0.27 anhydrous sodium sulfate has been used for binding the water. The mole ratio range was 0.25–0.75 for anhydrous sodium sulfate/water, and 0.32–1.3 for sulfuric acid/anhydrous sodium sulfate.
    Materialart: Digitale Medien
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  • 151
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 663-667 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Gas solubilities ; Enthalpies of solution ; Polar solutions
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The gas-liquid chromatographic method has been used to determine the solubilities and partial molar enthalpies of solution of the gases H2S, CO2 and COS in four polar solvents. The results agree well with literature values obtained using conventional techniques, with the one exception of H2S in N-methyl-2-pyrrolidinone. In this case there is some evidence for the occurrence of adsorption at the gas-liquid interface.
    Materialart: Digitale Medien
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  • 152
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Esterification in aqueous solution ; n-Butyl esters of aromatic polycarboxylic acids
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The direct esterification and gas chromatographic analysis of aromatic carboxylic acids as n-butyl esters is described. Derivatization is performed in aqueous solution with n-butanol in the presence of sulfuric acid. The butyl esters of benzoic, phthalic, hemimellitic, trimellitic, trimesic and pyromellitic acids permit their gas chromatographic separation from each other and from fatty acids and alipatic dicarboxylic acids. At mole ratios of [H2O]/ [n-BuOH]≤0.04 the water present does not interfere with the esterification reaction. At mole ratios above 0.04 anhydrous sodium sulfate is used for binding the water, at mole ratios of [Na2SO4 anh.]/[H2O]=0.25–0.75.
    Materialart: Digitale Medien
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  • 153
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 202-204 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Polysiloxane stationary phases ; Heat of adsorption ; Heat of solution
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The changes in the heat of solution of polar compounds and xylene isomers in methylsilicone fluid OV-101 deposited on Chromosorb W AW DMCS were studied. It was shown that the heat of solution increases with an increase of the percentage loading of the OV-101 up to 10%. Solution and adsorption thermodynamic characteristics of the studied system are briefly discussed.
    Materialart: Digitale Medien
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  • 154
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Metal complexes ; Chemically bonded phase
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Packings consisting of diphenylphosphine complexes with CoCl2 and CoBr2, chemically bonded to the silica surface, were synthesized and their retention parameters determined. The packings are capable of specifically interacting with electron-donating compounds by forming π-complexes. The interaction is considerably stronger in the case of CoBr2-containing packing than in the case of CoCl2-containing packing.
    Materialart: Digitale Medien
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  • 155
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 234-238 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Open-tubular columns ; On-column injection ; Stopped-flow operation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A simple, inexpensive, on-column injector of the septum moving-needle kind is described for quantitative analysis using open-tubular columsn. when operated in the stopped-flow mode an improvement incolumn efficiency is observed combined wit a diminished tendency to produce split-top peaks, particularly for late eluting peaks. Using electronic integration a relative error of about 2.7% was observed for peaks spanning a wide range of sample concentrations and volatilities.
    Materialart: Digitale Medien
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  • 156
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 243-248 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Carrier gas ; Viscosity ; Influence of temperature
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The vicosity-temperature relationship of the three gases (helium, nitrogen and hydrogen) most frequenly used as the carrier gas in gas chromatography is studied. Based on available data, equaitions are derived to describe this relationship. Using these equations viscosity data are tabulated for the chromatographically important temperature range.
    Materialart: Digitale Medien
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  • 157
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 260-264 
    ISSN: 1612-1112
    Schlagwort(e): Parabens and their dissolution ; Pharmaceutical dosage forms ; Derivatization ; Gas chromatography
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A specific, sensitive and general applicabla gas chromatographic method is described for the determination of parabens in various liquid pharmaceutical preparations: propylparaben and butylparaben in a liquid antacid dosage form (I); methylparaben, ethylparaben and propylparaben in a syrup (II); methylparaben and propylparaben in a solution for injection (III). Each time one of the parabens is used as internal standard. The parabens are extracted with diethylether and derivatized by silylation. Different columns are used for the analysis of the parabens: 3% SE-30 column, a 3% QF-1 column for different selectivity, a 2% OV-1 column for isothermal operation. Special attention is attributed to the standard: the parabens are dissolved in a minimal amount of 0.1 M sodium hydroxide and extracted in the same way as the pharmaceutical dosage form.
    Materialart: Digitale Medien
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  • 158
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 294-296 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Configuration ; Resolution ; Alcohols
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The study of the resolution of sixteen secondary aliphatic alcohols by gas chromatography on (+)-dodecyl (2R, 3R)-tartrate, trapping the ascending part of the peak from a conventional filled column, has allowed the determination in a single operation of the sign and order of emergence of enantiomers. A correlation between the configuration of these secondary alcohols and their order of emergence has been established.
    Materialart: Digitale Medien
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  • 159
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 309-312 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Carboxylic acids ; Acetonyl derivatives
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary The preparation of the acetonyl esters of nine aliphatic carboxylic acids is described, the general formula of the derivatives being RCOOCH2COCH3 where R=alkyl or H. The derivatives show good chromatographic properties on both packed and capillary columns. The electron impact and chemical ionisation mass spectra of the derivatives are discussed.
    Materialart: Digitale Medien
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  • 160
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 449-455 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Thermodynamic relationships ; Retention index ; Peak identification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary A thermodynamic criterion, ΔQ, is suggested which permits to estimate the difference in the functional group energy of interactions for two different stationary phases. The linear dependence of ΔQ on the homolog number m of any series Rm X can be used as the thermodynamic criterion for the identification of substances by GC analysis.
    Materialart: Digitale Medien
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  • 161
    Digitale Medien
    Digitale Medien
    Springer
    Chromatographia 18 (1984), S. 477-488 
    ISSN: 1612-1112
    Schlagwort(e): Gas chromatography ; Open tubular (capillary) columns ; Sample capacity ; Column comparison ; Film thickness ; Column diameter
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Summary Wall-coated, open-tubular (capillary) columns prepared from different diameter tubing, with different liquid phase film thickness, are compared with each other and with packed and support-coated open-tubular columns. The comparison is based on the variation of the phase ratio and the capacity factor, and includes column efficiency (HETP, theoretical plate number), resolution, retention time, and sample capacity. Problems associated with the evaluation of the sample capacity are outlined. The influence of temperature on column performance is discussed in detail. Finally, the possibilities of short, wide-bore open-tubular columns prepared with a thick liquid-phase film are demonstrated.
    Materialart: Digitale Medien
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  • 162
    Digitale Medien
    Digitale Medien
    Springer
    European journal of applied physiology 52 (1984), S. 235-242 
    ISSN: 1439-6327
    Schlagwort(e): Collagen ; Fast and slow twitch fibres ; Skeletal muscle ; Rat ; Endurance training
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The appearance of collagen around individual fast twitch (FT) and slow twitch (ST) muscle fibres was investigated in skeletal muscles with different contractile properties using endurance trained and untrained rats as experimental animals. The collagenous connective tissue was analyzed by measuring hydroxyproline biochemically and by staining collagenous material histochemically in M. soleus (MS), M. rectus femoris (MRF), and M. gastrocnemius (MG). The concentration of hydroxyproline in the ST fibres dissected from MS (2.72±0.35 Μg·mg−1 d.w.) was significantly higher than that of the FT fibres dissected from MRF (1.52±0.33 Μg·mg−1 d.w.). Similarly, the concentration of hydroxyproline was higher in ST (2.54±0.51 ⧎g·mg−1 d.w.) than in FT fibres (1.60±0.43 Μg·mg−1 d.w.), when the fibres were dissected from the same muscle, MG. Histochemical staining of collagenous material agreed with the biochemical evidence that MS and the slow twitch area of MG are more collagenous than MRF and the fast twitch area of MG both at the level of perimysium and endomysium. The variables were not affected by endurance training. When discussing the role of collagen in the function of skeletal muscle it is suggested that the different functional demands of different skeletal muscles are also reflected in the structure of intramuscular connective tissue, even at the level of endomysial collagen. It is supposed that the known differences in the elastic properties of fast tetanic muscle compared to slow tonic muscle as, e.g., the higher compliance of fast muscle could at least partly be explained in terms of the amount, type, and structure of intramuscular collagen.
    Materialart: Digitale Medien
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  • 163
    Digitale Medien
    Digitale Medien
    Springer
    Journal of chemical ecology 10 (1984), S. 1007-1018 
    ISSN: 1573-1561
    Schlagwort(e): Rat ; Rattus norvegicus sp. ; odorants ; stress ; behavior ; open field ; corticosterone ; fox dropping ; ketone ; sulfur ; compounds ; tans ; mercaptoketones ; repellent ; structure-activity
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The stress for 12 sulfur-containing synthetized volatiles was evaluated in male Wistar rats and compared to that for fox-dropping extract concentrate. Stress behavior was analyzed by quantifying various stress responses in a standard open field and measuring the increase in plasma corticosterone concentration. Nine compounds induced stress—a dihydrothiazole, two cyclic polysulfides, five mercaptoketones, and a mercaptan. For the mercaptoketones, the following structure-activity relationships were observed. Size can vary considerably; the mercapto group can be either alpha or beta and either secondary or tertiary. The keto group is not essential, since a structurally related mercaptan remains active. The mercapto group is essential for activity in mercaptoketones, since conversion to a methyl sulfide resulted in a neutral response. This type of odorant could function as an allomone and may have potential in rat control as an area repellent.
    Materialart: Digitale Medien
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  • 164
    ISSN: 1435-2451
    Schlagwort(e): Hyperthermia ; Induced colonic carcinoma ; Rat ; Chemotherapy ; BCNU ; Ftorafur
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Hyperthermie zur Behandlung von Tumoren wird seit längerem in In-vitro- und In-vivo-Versuchen und auch in der Klinik in verschiedenen Anwendungsformen erprobt. Bei der Kombination von Hyperthermie mit Chemotherapie wird eine überadditive cytostatische Wirkung beschrieben. In einem klinisch orientierten, kontrolliert durchgeführten Tierversuch wurde an einem durch N-Nitrosoacetoxymethylmethylamin (AMMN) induzierten autochthonen Coloncarcinom bei Sprague-Dawley-Ratten eine lokale, moderate Hyperthermie (43,5°C, 3 × 60 min) und eine Kombinationsbehandlung von Hyperthermie und Polychemotherapie (BCNU und Ftorafur) durchgeführt unter endoskopischer Diagnosestellung und Verlaufskontrolle. Es konnte keine Überlebenszeitverlängerung durch die angewendeten Therapien und keine additive Wirkung der lokalen moderaten Hyperthermie in Kombination mit der Chemotherapie bei diesem „harten”, d. h. relativ chemotherapieresistenten, Tumormodell gesehen werden.
    Notizen: Summary The use of hyperthermia for the treatment of tumors has been tested in in vitro and in vivo experiments as well as clinically for a long time. Combination of hyperthermia with chemotherapy was reported to result in overadditive cytostatic effects. In a clinically adapted, controlled animal experiment, local moderate hyperthermia (43.5°C, 3 × 60 min) alone and in combination with polychemotherapy (BCNU and Ftorafur) was used for the treatment of AMMN-(N-nitrosoacetoxymethyl-methylamine) induced autochthonous colonic carcinomas in Sprague-Dawley rats. Diagnosis and follow-up inspections were carried out endoscopically. The applied therapies did not result in prolonged survival times, nor was an additive effect seen after combined hyperthermia and chemotherapy in this “hard”, i. e. relatively chemotherapy-resistent, tumor model.
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  • 165
    ISSN: 1435-2451
    Schlagwort(e): Hyperthermia ; Yoshida sarcoma ; Chemotherapy ; BCNU ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Hyperthermie zur Cytostase von Malignomen ist in zahlreichen In-vitro- und In-vivo-Untersuchungen beschrieben worden. Die Kombination von Chemotherapie mit Hyperthermie soll zur Potenzierung der therapeutischen Wirkung führen. Ein Forschungsgegenstand ist der zeitliche Abstand zwischen beiden Therapiemodalitäten. Anhand eines Yoshida-ColonModells bei Sprague-Dawley-Ratten wurde eine lokale Hyperthermie (43°C, 60 min) im Abstand von 0, 3, 6, 9, 12 und 24 h nach einer Chemotherapie mit BCNU durchgeführt. Die Ergebnisse zeigten keine signifikante Steigerung der Heilungsrate durch die Hyperthermie. Angesichts unserer Ergebnisse sollten z.B. die mit groben Hoffnungen propagierten hyperthermen Peritoneallavagen erst im Tierexperiment einer kontrollierten Untersuchung unterzogen werden.
    Notizen: Summary There are numerous reports on in vitro and in vivo investigations of hyperthermia for cytostasis of malignant tumors. Combination of chemotherapy and hyperthermia is to potentiate the therapeutic effect. The time interval between the two types of therapy was the main subject of the present investigation. Local hyperthermia (43°C, 60 min) following BCNU chemotherapy at intervals of 0, 3, 6, 9, 12, and 24 h, respectively, was studied in a colonic Yoshida sarcoma model in Sprague-Dawley rats. No significant increase in the curing rate resulted from hyperthermic treatment. The results suggest that the highly anticipated hyperthermic peritoneal lavages should be investigated in controlled animal experiments prior to clinical use.
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  • 166
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 179 (1984), S. 229-242 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Wild-collected adults of Bombina orientalis are bright green dorsally and red to red-orange ventrally. As a prelude to an analysis of the differentiation of pigment cells in developing B. orientalis, we describe structural and chemical aspects of the fully differentiated pigment pattern of the “normal” adult.Structurally, differences between dorsal green and ventral red skin are summarized as follows: (1) Dorsal green skin contains a “typical” dermal chromatophore unit comprised of melanophores, iridophores, and xanthophores. Red skin contains predominantly carotenoid-containing xanthophores (erythrophores), and skin from black spot areas contains only melanophores. (2) In ventral red skin, there is also a thin layer of deep-lying iridophores that presumably are not involved in the observed color pattern. (3) Xanthophores of red and green skin are morphologically distinguishable from each other. Dorsal skin xanthophores contain both pterinosomes and carotenoid vesicles; ventral skin xanthophores contain only carotenoid vesicles. Carotenoid vesicles in dorsal xanthophores are much larger but less electron dense than comparable structures in ventral xanthophores.The presence of carotenes in ventral skin accounts for the bright red-orange color of the belly of this frog. Similar pigments are also present in green skin, but in smaller quantities and in conjunction with both colored (yellow) and colorless pteridines. From spectral data obtained for xanthophore pigments and structural data obtained from the size and arrangement of reflecting platelets in the iridophore layer, we attempt to explain the phenomenon of observed green color in B. orientalis.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 167
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
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  • 168
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 29-35 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: This study describes intercellular bridges in the ovaries of neonatal gerbils. Electron microscopy has revealed the presence of true intercellular bridges, connecting oogonia or oocytes, in ovaries of newborn gerbils. The cytoplasm of the intercellular channels is similar to that of the connected cells, with mitochondria, smooth and rough endoplasmic reticulum, and free ribosomes present. Lysosomes are also occasionally present in the intercellular bridges and they may be involved in early waves of oocyte atresia. An electrondense substance, 350-500 Å thick, is located immediately beneath the unit membrane of the intercellular bridges. Accumulation of electron-dense material increases the thickness of the walls of the intercellular bridges, supporting and maintaining the patency of the channels. It is suggested that the intercellular channels probably allow the interchange of nutrients, organelles, and possibly regulatory materials as well.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 169
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 55-68 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A comparative study of the forelimbs of the semifossorial prairie dog, Cynomys gunnisoni, and the scansorial tree squirrel, Sciurus niger, was focused on the musculoskeletal design for digging in the former and climbing in the latter. Based on lever arm mechanics, it was expected that the forelimb of the prairie dog would show features appropriate to the production of relatively large forces and that of the fox squirrel to relatively great velocity. Force and lever arm measurements were made of select forelimb muscles at the shoulder, elbow, and wrist joints for a series of angles in both species. Contraction time and fatigue indexes were determined for the same forelimb muscles. Contrary to expectation, in the few cases in which significant (P 〈 .05) differences were found, the forces, lever arms, and torques (force times its lever arm) were greater in the smaller fox squirrel. The observed variation in the torques produced fits the demands on the forelimb during climbing and digging as estimated from films. Several forelimb muscles of the fox squirrel show significantly higher mean contraction times than do the homologous muscles of the prairie dog. There were no significant differences between the two species in the fatigability of the selected forelimb muscles, although the mean fatigue index was always higher (less fatigable muscle) in the prairie dog. Similarities in the forelimbs of these two sciurids suggest that only minor modifications may have been required of the ancestral forelimb in order for descendent forms to operate successfully as climbers and diggers.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 170
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 105-124 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The anatomy of neurons of the stomatogastric nervous system of Ascheta domesticus was studied using heavy metal iontophoresis through cut nerve ends followed by silver intensification. Nineteen categories of neuron are described and compared with neurons known from the stomatogastric nervous system of other insects. Possible functions for the neurons are suggested. Motor neuron candidates are suggested for all parts of the gut served by the stomatogastric nervous system, and axons of sensory neurons of the anterior pharynx are located. There are four neuron types that cannot readily be assigned motor, sensory, or interneuron functions: large dorsal cells of the frontal ganglion; the two neurons of the nervus connectivus, and two categories of neurons in the median neurosecretory cell group of the pars intercerebralis, the axons of which are contained in the stomatogastric nerves.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 171
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 159-169 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: In the pedicellar segment of the fly antenna there is a large campaniform sensillum. The central projection of the sensory cell (LCC) of this large campaniform sensillum is described from labeling with horseradish peroxidase (HRP) and cobalt. The LCC projects bilaterally to several regions of the brain and subesophageal and thoracic ganglia. The LCC processes in these termination areas were analyzed in relation to other neural processes, including the remaining antennal sensory and motor projection. This analysis was aided by combining HRP labeling with Golgi silver impregnation. Based on earlier findings and the present data we suggest that the LCC, with its various outputs in, e.g., antennal and leg motor centers, serves as a multifunctional sensory path involved in control functions necessary in flight.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 172
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 173
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 173-180 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: During the long starvation period (November to June) of the lizard (Varanus exanthematicus), pancreatic B cells undergo profound modification. The degeneration of β granules observed in electron microscopy appears correlated with the diminution of the immunoreactive insulin-like content of the pancreas. The analogy between the phenomena observed here and those reported in animals treated with alloxan is discussed.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 174
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 195-211 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The structure and crystallography of the internal shell of the pulmonate gastropod slug Limax maximus were studied at the levels of light and scanning electron microscopy, revealing patterns of shell ontogeny and morphogenesis. The calcified portion of the slightly convex ovoid shell is composed of a single palisade layer of calcitic crystals. Numerous projections, 100 μm in width at the dorsal tip, are found on the dorsal surface of the shell and coincide with local nucleation sites of primordial calcium salt deposition onto the periostracum. With continued calcification these projections coalesce ventrally, forming the single crystalline shell layer. The organic portion of the shell includes the periostracum and an extensive PAS-staining conchiolin. In EDTA-etched preparations, conchiolin appears as a spongy network of fibers throughout the shell. Both horizontal and vertical components of the conchiolin are present, the former of variable thickness and occurring in an intercrystalline manner, the latter always occurring normal to the horizontal set. Macromorphogenic growth is characterized by three distinct temporal stages. Primary growth occurs radially from the umbonal region. Secondary growth is synonymous with shell thickening. Tertiary growth is characterized by both a lateral component, in which the shell extends beyond the primary growth boundaries, and a ventral component, in which the shell continues to grow in thickness. SEM of the ventral shell surface reveals a pattern of growth at the crystalmatrix interface. Proteinaceous fibers of the conchiolin occur unidirectionally in horizontal rows. Zones of incipient calcitic crystallization onto these hypostracal fiber bundles are contrasted by zones of increasing crystallization until the fibrous template (reduced hypostracum) is completely covered by crystals.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 175
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 271-296 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Electron microscopy shows that the pharyngeal lining of the larval lamprey Petromyzon marinus is a structurally complex epithelial system that can be separated into eight epithelial types: gill lamellar, gill interlamellar, goblet cell, protective, terminal (taste) bud, preciliated, ciliated in tracts, and ciliated in grooves. Furthermore, these epithelial types encompass at least sixteen different cell types based on ultrastructure and, in some cases, correlative histochemistry (PAS, Alcian blue). Common to nearly all the epithelial types are basal cells and intermediate cells. These two cell types are seen as undifferentiated. Among mature cells, structural specialization as proceeded in three directions: (1) elaboration of mitochondria, probably related to molecular transport (ion-uptake cells, chloride cells); (2) ciliogenesis (preciliated and ciliated cell types); and (3) production of mucous secretory granules (mucous-platelet cells, goblet cells, superficial protective cells, columnar mucous cells, “cobblestone” cells, and marginal and dark cells in the terminal buds). Many of the functions of the cell types relate to the process of suspension feeding in this animal.
    Zusätzliches Material: 33 Ill.
    Materialart: Digitale Medien
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  • 176
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 243-252 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A small short muscle frequently acts across a joint in parallel with a vastly larger and longer muscle; therefore it should play a minimal role in the mechanical control of that joint. This study provides evidence suggesting that the small member of such a “parallel muscle combination” (PMC) may serve an important sensory feedback role. The spindle densities of large and small members of PMCs in man and the dog were determined and compared. Epaxial PMCs controlling canine intervertebral joints were dissected and tissue samples were embedded in paraffin, sectioned transversely to the muscles' long axis and, stained with hematoxylin-periodic acid-Schiff (PAS). Representative tissue sections were projected on to stereological grids and the percentage volume of spindles was determined. Data existing in the literature were used to ascertain spindle densities in human PMCs controlling joints in the cervico-occipital region and the extremities. The spindle density for each muscle in a group of PMCs controlling a particular motion was listed, and the mean spindle densities were determined for both the large and the small members of the group. Student's unpaired t test was used to determine the significance of the differences between mean spindle densities. Linear regression was calculated and the data were plotted graphically.In all PMCs examined, the spindle density of the small muscles was significantly higher than that of their large counterparts. It is therefore proposed that the small muscles of PMCs may function as “kinesiological monitors” generating important proprioceptive feedback to the central nervous system.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 177
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 1-8 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The internal reproductive apparatus of female Platynotus punctatipennis is composed of the paired ovaries, paired lateral oviducts, common oviduct, spermatheca associated with its accessory gland, and a bursa copulatrix. The accessory (colleterial) glands are absent. The ovary is made up of a large number of telotrophic ovarioles which are covered by a double-layered peritoneal sheath. The terminal filament is separated from the germarium by the basement membrane of the latter and consists of a syncytial core surrounded by the peritoneal sheath. Nutritive cords are absent. The pedicel shows highly eosinophilic and PAS-positive secretion of obscure origin. The spermatheca reveals a number of interesting features. It is composed of a pair of sperm-storing tubules, enclosed in a very thin muscle layer. A winecup-like structure, provided with a thick coat of circular muscles, connects the spermathecal gland with thespermathecal duct. Four types of intimal linings occur in the spermatheca and its associated structures. The wine-cup-like connection and four types of intima are entirely new features observed. Histology of the various parts of the reproductive apparatus is described.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 178
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 29-47 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The formation of somites, coelomic sacs, splanchnic mesoderm, fat bodies, circular system, gonads, and musculature in the embryo of the primitive moth, Neomicropteryx nipponensis Issiki, is described. The following paired somites are formed: the labral, antennal, intercalary, mandibular, maxillary, labial, three thoracic, and 11 abdominal. Small but distinct coelomic cavities appear in all these somites. Labral somites differentiate into the labral muscles, stomodaeal muscles, and dorsal dilator muscles of the pharynx. Antennal somites differentiate into the antennal muscles, aorta, and the ventral dilator muscles of the pharynx. Intercalary somites are short-lived, disintegrating to liberate many free cells into the yolk. The suboesophageal body is not formed. Mandibular somites differentiate into the mandibular flexor and extensor muscles. Maxillary and labial somites differentiate into the splanchnic mesoderm, fat bodies, and into muscles of the maxillolabial region. Three pairs of thoracic and ten pairs of abdominal somites split into the splanchric and somatic mesoderm. The 11th abdominal somites merge into the proctodaeal mesoderm, and differentiate into the musculature of the hindgut. The heart is formed by the fusion of the cardioblasts derived from the first thoracic to the tenth abdominal segment. The aorta arises from the antennal median mesoderm. Blood cells are derived from the median mesodermal cells of the maxillary to the tenth abdominal segment. Germ cells appear at the mediodorsal corner of each somite in the fifth abdominal segment. They become enclosed with a mesodermal sheath to form a pair of rudimentary gonads in this segment. Major muscles in the head, thorax, and abdomen of the fully grown embryo are described.
    Zusätzliches Material: 40 Ill.
    Materialart: Digitale Medien
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  • 179
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 180
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 155-160 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The architectural and histochemical properties of the anatomically distinct compartments of the semitendinosus muscle (ST) of mice, rats, guinea pigs, and rabbits show that the ST is composed of two separate compartments aligned in series - a destal compartment (STd) and a proximal one (STp). The STp is further subdivided into a ventral head (STpv) and a dorsal head (STpd). The muscle fibers were arranged in parallel to the line of muscle pull within each compartment. The STd has the longest and the STpv the shortest fibers in all species. The physiological cross-sectional area and the estimated tetanic tension was greatest in the STd. Based on the staining pattern for myosin ATPase (alkaline preincubation) and an oxidative indicator (NADH or SDH), the STpv has the highest percentage of slow-oxidative (SO) or SO plus fast-oxidative-glycolytic (FOG) fibers of any portion of the muscle. The differences in fiber-type distributions and architectural designs of the separate compartments suggest a specialization of function of the individual compartments.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 181
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 97-131 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The three-dimensional structure of the organ of Bellonci in the marine amphipod Gammarus setosus and the relationship between its sensory cells and concretion are described using light, transmission, and scanning electron microscopy, with chemical treatment for cell lysis, calcium chelation, glycogen staining, and lanthanum labelling. The organ is encapsulated and has three units called fuselli. Each is enclosed by two fusellar cells which generate and release calcium granule strands into the cores of the fusellar concretions, which are united in the center of the organ. The surface of each fusellus is traversed by spiral dendrites entering dorsally and ending ventrally. The spiral dendrites arise from sensory neurons contained in a palm-shaped ganglion in the center of the capsule, beyond which they are twisted like a rope before reaching the concretion. The spiral dendrites are linked in pairs by gap and tight junctions and each gives origin to two pairs of 9+0 sensory cilia 30 μm apart. The ciliary distal segments give rise to long tubules which are in contact with the calcium granule strands. The ciliary proximal segments are expanded by many long mitochondria which interdigitate with the branched striated ciliary rootlets. The concretion is suspended in the capsule cavity by axons originating from four neurons of a remote mechanoreceptor. The structure of the organ suggests that it is a sensory organ involved in the reception and integration of a variety of stimuli.
    Zusätzliches Material: 86 Ill.
    Materialart: Digitale Medien
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  • 182
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The fine structure of the kidney and the bladder of the bullfrog (Rana catesbeiana), the bullfrog tadpole, and the mudpuppy (Necturus maculosus) were studied with special attention to the innervation of renal tubule cells and bladder epithelial cells. In the bullfrog kidney, nerve terminals and varicosities were frequently associated with the tubule cells, apparently in an increasing order from the proximal tubule to the connecting tubule. Although these terminals and varicosities did not directly contact the tubular cell membrane, an aggregation of synaptic vesicles on the side facing the tubule was considered as morphological evidence that neurotransmitter can be released here and can affect the transport activity of the tubule cells. The association of nerve varicosities with canaliculi cells in the connecting tubule was also demonstrated. In the bullfrog tadpoles, renal tubule cells were occasionally innervated. In the mudpuppy, renal tubule cells were only poorly innervated. The epithelium of the bullfrog bladder was commonly innervated. Nerve terminals with synaptic vesicles were located very near basal cells and even contacted them directly on rare occasions. In the mudpuppy, the innervation of the bladder epithelium was observed infrequently. The bullfrog tadpoles did not possess an apparent bladder. In all materials studied, renal arterioles and bladder smooth muscle cells were innervated.
    Zusätzliches Material: 16 Ill.
    Materialart: Digitale Medien
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  • 183
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 184
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 179 (1984) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 185
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 179 (1984), S. 13-19 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Cytoplasmic microtubules can be divided into two subpopulations: (1) those adjacent to the nucleus (perinuclear), and (2) those distributed between the myofilament bundles (nonperinuclear). Previous observations (Cartwright and Goldstein, '83) indicate total cytoplasmic microtubule numeric density increases to a maximum at 5-9 days and decreases to the steady value of the adult muscle. We have examined the numeric density (mean numbers of microtubule profiles per μm2 cross-sectional area) of the perinuclear subpopulation and compared it to the numeric density of the total cytoplasmic microtubule population in postnatally developing rat papillary muscle ages 1, 3, 5, 9, 21, and 42 days, and adult. The perinuclear region was defined as the area around the nucleus which extends to the 0.273 μm from the nuclear envelope. The density of perinuclear microtubules did not change with postnatal development. Our study suggests that perinuclear microtubules are a separate and relatively stable subpopulation of the total population of cytoplasmic microtubules and may serve a function different from that of the more variable nonperinuclear microtubules.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
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  • 186
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 19-28 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Each antenna of both sexes of adult Rhodnius prolixus has approximately 570 mechanosensitive neurons that innervate five morphologic types of cuticular mechanosensilla: campaniform sensilla, tapered hairs, trichobothria, and type I and type II bristle sensilla. Each campaniform sensillum and tapered hair is presumably innervated by one mechanosensitive bipolar neuron and probably functions in proprioception. The campaniform sensilla being located at the base of the scape could monitor the position of the antenna. Tapered hairs are found at the distal margin of flagellar segment I and projecting laterally from the bases of the pedicel and scape. They probably provide information about the relative positions of the antennal segments. Seven trichobothrium are located on the pedicel and three on flagellar segment I. Each trichobothrium has a long filamentous hair inserted into the base of a socket that extends inwardly as a cuticular tube and is innervated by one bipolar neuron with a tublar body, a parallel arrangement of microtubules associated with electron-dense material. The trichobothria may respond to small variations in air currents.Type I bristles occur at the base of the antenna and are the most numerous type of mechanosensillum; an average of 452 occur on each antenna of females and 440 on males. The bristle is curved toward the antennal shaft and is serrated distally. Type II bristles are located distally and are the second most numerous type of mechanosensillum; an average of 88 were counted on each antenna of females and 94 on males. The type II bristle is straight with small, longitudinal, external grooves and projects laterally from the antennal shaft. Each type I and II bristle sensillum is innervated by a bipolar neuron whose dendrite is divided into an inner and outer segment. The outer segment is encased by a dendritic sheath which may be highly convoluted and distally contains a tubular body. Two sheath cells are associated with each sensillum. Both types of bristle sensilla have a tactile function.The tubular bodies of both types of bristle sensilla have a complex structure indicating that they are very sensitive. Variations in the amount and arrangement of the electron-dense material at the tip of the tubular bodies may reflect differences in viscoelastic properties that underlie functional characteristics.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
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  • 187
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 69-79 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Fine structural study indicates that the neuromuscular system of stage I polyps of Aurelia aurita is exclusively ectodermal.The three major muscle fields are the radial muscles of the oral disc, the longitudinal muscles of the tentacles, and the muscle cords of the septae and the column; the muscle fields are in physical continuity at the peristomial pits and share a common innervation and type of myofibril. The myofibril is striated in the tentacle base, in the outer oral disc, and in the upper part of the muscle cord; it grades into a smooth muscle toward the tentacle tip, the mouth, and the lower part of the cord. There is a fourth field of longitudinal smooth muscle in the pharynx.The nervous system consists of an epithelial sensory cell in the tentacle and a single type of neuron found in the subepithelial layer of the tentacle, oral disc, and muscle cord. The lack of gap junctions suggests that there is no nonnervous conduction system. The subepithelial layer also contains three types of fibers and a type of soma which cannot be characterized as neuronal. The soma is identified as the “neurosecretory cell” described in Chrysaora. The absence of neuromuscular elements in the column and stolon distinguishes the Aurelia aurita collected from Washington, USA, from English polyps previously described.
    Zusätzliches Material: 28 Ill.
    Materialart: Digitale Medien
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  • 188
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 125-144 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The structure and interrelationships of the mouthparts and of the food canal and its accessory cephalic structures of the females of Simulium venustum are described through microscopic observations. The mouthparts that enter the would during feeding are the mandibles, maxillary laciniae, hypopharynx, and labrum and collectively form a “syntrophium.” The labium and labellar lobes, which do not enter the wound, ensheathe the syntrophium distally and must be retracted to allow biting.We present an interpretation of mouthpart function during biting that emphasizes how biting steps are accomplished and what sensory structures are used to monitor the process. Four phases of biting are identified: (1) initial penetration of the skin effected by the mandibles; (2) consolidation of mouthpart position involving anchoring the syntrophium into the wound by means of the barbed laciniae; (3) diet sampling and active feeding - food (blood) is pumped by three groups of muscles forming two functional pumps, one located in the cibarium, the other in the pharynx. These pumps are separated from each other and from surrounding regions of the food canal by valve muscles making the pumping process a complex and highly coordinated series of muscular contractions; and (4) mouthpart disengagement involving removal of the laciniae, thus releasing the syntrophium from the wound.
    Zusätzliches Material: 30 Ill.
    Materialart: Digitale Medien
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  • 189
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 37-54 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: The external morphology of contact-chemoreceptive hairs (taste hairs) of six fly species, Calliphora vicina, Lucilia caesar, Musca domestica, Phormia terranovae, Sarcophaga carnaria and Stomoxys calcitrans, is described. The species can be distinguished by the differences between the patterns of taste hairs at the ventral side of their prothoracic tarsi. Taste hairs can be subdivided into morphological types, using the shape of the cuticle around the apical pore as criterion, even though this shape changes slightly on opening and closing of the pore. Light microscopical studies reveal that the nature and osmolarity of stimuli are decisive for the effect stimuli have on the shape of the top of the labellar hairs. The motions of the apical cuticle appear to be reversible.Gentle ultrasonic treatment preserves the shape of the cuticle of the top and the diameter of the pores on fluid stimulation. This technique makes it possible to study the effect of a previous stimulation on both tarsal and labellar hairs with the scanning electron microscope. It is supposed that stimuli can affect cuticular components around the pore, producing volume changes in that cuticle which alter the diameter of the pore.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
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  • 190
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984) 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Materialart: Digitale Medien
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  • 191
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 180 (1984), S. 297-308 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: During the breeding season, male anurans display clasping behavior by holding females with their forelimbs. This behavior is peculiar to males, and may require specializations in forelimb musculature. The present study revealed that five kinds of forelimb muscles were heavier in the male Japanese toad than in the female: the flexor carpi radialis (FCR), the flexor antibrachii medialis caput superius (FAMsup), the abductor indicis longus (AIL), the extensor carpi radialis caput superius (ECRsup), and the flexor antibrachii lateralis superficialis caput superius (FALSsup). In addition, one breast muscle, the coracoradialis (CR), was also heavier in males than in females. A quantitative analysis of muscle fibers processed for myosin ATPase activity showed that, in such “sexually dimorphic muscles” of the female, both fast (twitch) and slow (tonic) muscle fibers were of smaller diameter than in other forelimb muscles of both sexes (all male muscles plus “nondimorphic muscles” of the female). Moreover, both types of fibers were less numerous than in the corresponding muscles of the male. These results suggest that the “sexually dimorphic muscles” are used especially for clasping by the male and are degenerative or subnormal in the female. Slow muscle fibers were neither peculiar to, nor abundant in, these clasping muscles, although they may well be necessary for tonic and prolonged contractions of the forelimb muscles during clasping. The mechanism of sexual dimorphism may be a direct action of androgens on clasping muscles or an indirect action on clasping muscles via the innervating motoneurons.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
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  • 192
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 21-28 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Shells from eggs of the turtle Kinosternon flavescens were examined during different stages of development with light and scanning electron microscopy. Prior to initiation of the calcareous layer, organic spheres or cores appear on the outer surface of the shell membrane. Presumably, these cores nucleate deposition of the mineral layer of the eggshell. Growing shell units of the mineral layer are rounded and nodular in shape, crystallites of adjacent shell units do not interlock, and numerous spaces occur between shell units. As growth continues, most of the spaces between shell units are obliterated, and shell units become more elongate in form. The calcareous layer of partially shelled eggs resembles the calcareous layer of flexible-shelled eggs of emydids and chelydrids. Eggshells assume the morphology typical of rigidshelled chelonian eggs only at an advanced stage of shell formation. These observations indicate that rigid and flexible eggshells may form by fundamentally similar mechanisms, with length of shell growth being the primary determinant of whether shells are flexible or rigid.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
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  • 193
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 69-86 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Hymenopteran venom glands are epidermal glands that have evolved from female accessory reproductive glands. In the honey bee, Apis mellifera L., the venom gland shows many of the fine structural features of primitive glands. A honey bee venom gland is a simple, long, thin, distally bifurcated structure, opening into an ovoid reservoir. Along most of the length of the gland are similar secretory units that have four major components (secretory cells, duct cells, ducts, and end apparatuses), except in the part of the gland proximal to the venom reservoir, where the secretory units resemble those around the venom reservoir. In the latter secretory units a funnel structure occurs between the duct (which is shorter than that of the secretory units of the gland) and the end apparatus. This funnel may be important in protecting the secretory cells around the reservoir from the cytolytic activity of the complex chemical mixture constituting the venom.
    Zusätzliches Material: 18 Ill.
    Materialart: Digitale Medien
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  • 194
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 175-204 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Anatomical studies of cephalic bones and muscles combined with cine and high-speed videographic analyses of feeding demonstrate that Amphiuma tridactylum uses two distinct types of suction feeding. Small or relatively immobile prey generally elicit a stationary capture mode in which mouth opening precedes buccal expansion and there is no forward movement of the head of the salamander. Actively moving prey are captured by a rapid strike during which mouth opening and buccal expansion are synchronous and the extent of buccal expansion is greater than in stationary feeding. Differences between these feeding modes may be due to differences in the timing of contraction of the rectus cervicis muscle. Synchronous hyoid and mandibular excursions during the strike are probably generated by simultaneous contractions of the depressor mandibulae and rectus cervicis, whereas delay of hyoid excursions during stationary capture suggests sequential contraction of the depressor and rectus cervicis.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
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  • 195
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 161-173 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Silver impregnation of serial histological sections of the tubeworm Chaetopterus variopedatus revealed the presence of a subepidermal nervous system. The anterior nervous system is delimited by the first 11 segments and comprises (1) two dorsolateral cerebral ganglia and lateral instead of ventral nerve cords which are widely separated and thus connected by unusually long commissures, (2) a pharyngeal ganglion in the fourth segment which is connected to the cerebral ganglia by pharyngeal nerves and constitutes along with the pharyngeal plexus a stomatogastric or enteric nervous system, and (3) small, presumably segmental ganglionic swellings along the lateral nerve cords from which emerge commissures and parapodial nerves. No subesophageal ganglion or periesophageal connective could be identified. The lateral nerve cords converge toward the midline in the 12th segment to form the posterior nervous system comprising a pair of ventromedian nerve cords with their repetitive segmental ganglia from which emerge numerous short commissures and three segmental nerves coursing toward the dorsal and ventral regions of parapods and toward the neuropod. Light and electron microscopic investigations of cerebral and segmental ganglia showed an arrangement of inner neuropile and of unipolar neuron somata at the periphery. The neuropile comprises numerous neurites ranging in diameter from 0.5 to 10 μm and making polarized or symmetrical synaptic junctions with each other. The pharyngeal ganglion consists of a similar neuropile and of a large mass of cell bodies which is traversed by an elaborate network of sinuses and harbors three types of neurosecretory cells in addition to the conventional neuron somata. These findings are interpreted in the framework of the highly specialized morphological features and habits of Chaetopterus, and the welldeveloped stomatogastric system is considered to be related to control of the feeding activities.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
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  • 196
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 297-303 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Whenever individuals of the freshwater sponge Ephydatia fluviatilis belonging to different strains come into contact, they reject each other by building a nonmerging front. The present work describes the development, the structure, and the nature of the barrier secreted between two individuals. The observations reported give unequivocal data about the collagen nature of the incompatibility barrier. First, ultrastructural investigations reveal the presence of fibrils and microfibrils which are, respectively, typical of collagen and spongin. Second, incorporation of tritiated proline, a characteristic precursor of collagen and related products, is particularly intense in the front. The involvement of several cell types in the barrier formation is discussed. The allogeneic incompatibility reaction between E. fluviatilis individuals appears very close to the process of allograft chronic rejection that we formerly described for some marine sponges. Both phenomena are basically analogous to the process which fixes to and isolates the sponges from their substrate.
    Zusätzliches Material: 9 Ill.
    Materialart: Digitale Medien
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  • 197
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 305-317 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Motor units of the medial gastrocnemius (MG) and the single lateral gastrocnemius/soleus (LG/S) muscles of the opssum (Didelphis virginiana) were found to have uniformly slow contraction times relative to homologous muscles of the cat. Though a broad range of peak tetanic tensions was found among motor units from both muscles, most of the motor units were quite large relative to tension of the whole muscle. Comparison of the relative sizes of motor units showed that those of LG/S are significantly larger and slower than the units of MG. This suggests that the motor units of the two muscles may be differentially recurited during different behaviors.All of the MG and LG/S motor units were highly or moderately resistant to fatigue. Histochemical staining for NADH-diaphorase activity indicated consistently high levels of the enzyme in all of the fibers of both muscles. Apparently, all of the fast motor units consist of fast oxidative/glycolytic (FOG)-type muscle fibers. Our data provide functional evidence that the types of myofibrillar ATPase demonstrated by Brooke and Kaiser ('70), are not necessarily correlated to physiological classification of fiber types as slow oxidative (SO), fast oxidative/glycolytic (FOG), and fast glycolytic (FG) (Peter et al., '72).Perhaps compartmentalization of muscle fiber types may be a first step in the separation of muscles into multiple heads during the evolution of specialization to diverse locomotor habits among the mammals.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
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  • 198
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 181 (1984), S. 333-347 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Sensory epithelia of the oral tube, a fungiform body anterior to the tentacles and of the terminal knob of tentacles, were studied in Ovatella myosotis by electron microscopy. All three epithelia consist of columnar support cells, sensory cells, and, except in the oral tube, numerous goblet cells. The epithelia differ significantly in their apical differentiations. In the oral tube an outer layer is formed by irregularly bent villi of support cells completely embedded in a surface coat. Cilia and cytofila of the dendrites of sensory cells intertwine throughout the entire depth of the villous layer. In the fungiform sensory body some of the villi of support cells are singly branched. Their basal region is free of a surface coat. In this region cytofila and cilia of dendrites form a spongy layer, some cytofila extending into the surface coat. In the tentacular terminal knob the villi of the support cells branch dichotomously once or twice, a single villus thus ending with 2-4 tips. Only these terminal twigs are invested with the surface coat. The cytofila and dendritic cilia are confined to a broad spongy layer underneath. Three types of dendrites are present. They differ in their number of cilia, structure of basal bodies and occurrence in the three epithelia. Dendritic cytofila are most abundant in the tentacular terminal knob and least numerous in the oral tube. The observations are discussed with respect to corresponding epithelia in other pulmonates, the homology of the fungiform body, and possible functional correlates of structural features.
    Zusätzliches Material: 28 Ill.
    Materialart: Digitale Medien
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  • 199
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 182 (1984), S. 63-69 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Renal tubules in the dog shark, leopard shark, and red skate were examined histologically and analyzed histochemically for enzymes. Cells of the distal and collecting tubules exhibit extensive interdigitations and large intercellular spaces, suggesting that these tubules are sites of sodium reabsorption. Although Na-K-ATPase is very scarce to nonexistent in the distal and collecting tubules, very intense carbonic anhydrase activity in these segments indicates that they secrete large amounts of hyrogen ion and reabsorb sodium by H+/Na+ exchange process. Epithelial cells of the necks are not interdigitated, tightly join adjacent cells, and have low enzyme activities. They seem to be passively permeable to the water. Necks are attached to the distal tubules with scant intervening stroma. It seems likely that the stroma has a high osmotic pressure resulting from absorption of solutes in the distal tubules. Water may be reabsorbed from necks to stroma because of a concentration gradient of the solutes distributed between these sites.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 200
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Light and electron microscopy were used to examine the morphology of the mucosa of the diverticulum, anterior intestine, and transition zone in prefeeding and spontaneously feeding adult lampreys (Petromyzon marinus L.). Absorptive (either types A or B), ciliated, and enteroendocrine cells are present in all regions but the diverticulum and anterior intestine also possess zymogen (secretory) cells. Type A absorptive cells are restricted to the diverticulum and the rostral one-third of the anterior intestine and are characterized by abundant mitochondria and an extensive smooth tubular network. Type B absorptive cells, in the remainder of the anterior intestine and the transition zone, possess small numbers of these organelles but in the transition zone also have inclusion bodies. During feeding, abundant lipid droplets and lipoprotein (VLDL) accumulate in the cytoplasm of both types of absorptive cells and in the lateral intercellular and the perivascular spaces. Lipid is present to a limited extent in ciliated cells and is encountered only rarely in enteroendocrine and zymogen cells. Although the animals are obligate sanguivores, there is little evidence of iron within these mucosal cells. It is suggested that intestinal efficiency displayed by this animal is due in part to ion transport in osmoregulation in type A cells, lipid absorption in types A and B cells, and digestion through enzymes in zymogen cells.
    Zusätzliches Material: 31 Ill.
    Materialart: Digitale Medien
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