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  • 1980-1984  (1,664)
  • 1975-1979
  • 1970-1974
  • 1982  (1,664)
  • Cell & Developmental Biology  (962)
  • Physics  (517)
  • Rat  (125)
  • Electron microscopy
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Years
  • 1980-1984  (1,664)
  • 1975-1979
  • 1970-1974
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Colloid & polymer science 260 (1982), S. 564-569 
    ISSN: 1435-1536
    Keywords: lin. Polyethylene ; Single crystals ; Heat of Fusion ; DSC ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Recently published results for solution crystallized PE single crystals have shown, that the experimental heat of fusionΔH * is higher, if the solvent is exchanged to silicon oil (oil suspension samples) as compared with dried mats. This has been interpreted by the collapse of the original hollow pyramids during drying, inducing lateral defects within the lamellae. The present investigation does not confirm this unexpected result.ΔH * of dried mats (T c 66 to 91 °C) and of the corresponding oil suspension samples agree within the rather small limits of experimental error. The crystallinities as derived fromΔH *, density or WAXS are in excellent agreement. SEM micrographs of cold fractured dried mats show their spongy macromorphology, but TEM micrographs of stained ultra-thin sections reveal the lamellar morphology of the walls, consisting of curved lamellae and stacked hollow pyramides. If a dried mat is sintered at room temperature, a dense transparent film is obtained with a rather regular stacked morphology of large flat lamellae.ΔH * of these films agrees with that of the original mat.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 236 (1982), S. 41-51 
    ISSN: 1434-4726
    Keywords: Prominentia spiralis cochleae ; Meerrettichperoxidase ; Elektronenmikroskopie ; Inner ear spiral prominence ; Horseradish peroxidase ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Transport of macromolecules in the spiral prominence of the guinea pig was studied after perilymphatic and intravenous horseradish peroxidase (HRP) injection. HRP was taken up by the spiral prominence epithelium from the perilymphatic space and in a much higher degree from the endolymphatic space. A highly endocytic ativity was shown by the stroma cells surrounding the spiral prominence vessel. HRP particles were stored in the cytoplasm within vesicles and vacuoles of different sizes and different contrasts. The mode of tracer storage in the spiral prominence epithelium and in the stroma cells from the morphological point of view suggests lysosomal digestion. HRP was transported from the perilymphatic space into the spiral prominence vessel lumen by means of vesicular transport through the vessel wall, while transport of the tracer from the vessel lumen into the perilymphatic space after intravenous injection was not observed.
    Notes: Zusammenfassung Nach perilymphatischer und intravenöser Applikation von Meerrettichperoxidase wurde der Transport des Makromoleküls in der Prominentia spiralis des Meerschweinchens verfolgt. Die Tracer-Partikelchen wurden aus dem perilymphatischen Raum und vornehmlich jedoch aus dem Ductus cochlearis in das Oberflächenepithel der Prominentia spiralis aufgenommen. Die das Vas prominens umgebenden Stromazellen nahmen relativ viel Meerrettichperoxidase auf, die im Zytoplasma in unterschiedlich großen und unterschiedlich kontrastreichen Vesikeln und Vakuolen abgelagert wurde. Die Art der zytoplasmatischen Ablagerung des Tracers in den Epithelzellen und den Stromazellen spricht vom morphologischen Aspekt her für einen lysosomalen Abbau. Meerrettichperoxidase wurde von der Perilymphe in das Lumen des Vas prominens transportiert. Dieser Transport erfolgte vesikulär durch das Gefäßendothel. Ein Transport des Tracers in umgekehrter Richtung wurde nach intravenöser Applikation nicht beobachtet.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European archives of oto-rhino-laryngology and head & neck 236 (1982), S. 67-79 
    ISSN: 1434-4726
    Keywords: Menière's disease ; Vestibular nerve ; Vestibular ganglion ; Pathologic alterations ; Electron microscopy ; Morbus Menière ; Nervus vestibularis ; Ganglion vestibuli ; Pathologische Veränderungen ; Elektronenmikroskopie
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Vestibularisganglien von 17 Patienten mit einem Morbus Menière wurden nach transtemporaler oder translabyrinthärer Neurektomie elektronenmikroskopisch untersucht. Als Vergleichsmaterial dienten drei Ganglien, die bei anderer Indikation entnommen wurden und vier postmortale Entnahmen von Ohrgesunden. Bei allen Menière-Präparaten zeigten sich am Bindegewebe gleichartige pathologische Veränderungen von unterschiedlich starkem Ausmaß. Sie bestanden in einer Zunahme des Kollagens, wobei sowohl unterschiedliche Kaliber des Faserquerschnittes als auch Veränderungen der Periodizität der Querstreifung beobachtet wurden. Aktive Fibroblasten und reaktive Schwannsche Zellen, die isoliert lagen, keinem Axon zugeordnet waren und deren z. T. hirschgeweihförmig verzweigte, dünne Zellausläufer Kollagenbündel umhüllten, wurden als Zeichen einer noch ablaufenden Kollagenbildung gedeutet. Die Blutgefäße wiesen häufig eine Vervielfachung der Basalmembran auf, die von einem mehrfach breiteren Saum einer homogenen Matrix umgeben war. Die Perizyten waren oft entweder nekrotisch oder teilweise nicht mehr zu beobachten. Die Endothelzellen wiesen in der Regel kein aktives Zytoplasma auf. Sie erschienen teilweise autolytisch. Die pinozytotische Aktivität erwies sich als auffallend verringert. Diese qualitativen Veränderungen im interstitiellen Gewebe könnten auf ein primär lokales pathologisches Geschehen im Bereich des Nerven und des Ganglions hinweisen.
    Notes: Summary Vestibular ganglia of 17 patients with Menière's disease, obtained by transtemporal or translabyrinthine neurectomy, were studied by electron microscopy. Three ganglia removed because of other disease and four ganglia of normal ears taken post mortem served as controls. The neuronal fibrous tissue of Menière cases showed without exception pathologic changes of various extent. The amount of collagen was increased, whereby different fiber diameters were observed as well as changes in the periodicity of cross banding. Signs of continuing collagen formation were found: active fibroblasts and an increased number of isolated Schwann cells without axons, showing deerhorn-like ramifications which enveloped collagen bundles. The blood vessels were frequently surrounded by multiple basal membranes and broad bands of homogenous matrix. The pericytes were either necrotic or nonexistent. The endothelial cell cytoplasma was usually not in an active state. Sometimes it seemed to be autolytic. The pinocytotic activity was strikingly diminished. These qualitative changes of the interstitial tissue might point to a local pathologic event in the region of the vestibular nerve and ganglion.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 231 (1982), S. 315-320 
    ISSN: 1432-0711
    Keywords: Ovarian cycle ; Physiology ; Catecholestrogens ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using highly stabilized catecholestrogen preparations-ascorbic acid added to the free alcohols or benzoic acid derivatives — 2- and 4-hydroxyestrogens were tested in simple, clearly defined animal models: As index for the peripheral action the influence on vaginal opening and uterus weight gain was monitored after continuous s.c. administration for 6 days (minipumps) in immature intact rats resulting in a relative estrogenic potency (estradiol = 100%) of 70–100% for 4-hydroxyestradiol and less than 30% for 2-hydroxyestradiol. As index for the central action LH levels were measured in adult ovx rats leading to the same relations in the relative potencies. As index for both central and peripheral actions LH levels and the formation of corpora lutea were investigated in animals with an intact but prepubertal feed-back loop, i.e. in 25-day-old immature rats. 4-Hydroxyestradiol in this model clearly triggered LH surges and induced ovulations, its potency being in the same range as that of estradiol. 2-Hydroxyestradiol, in comparable doses, again showed no significant effect. Finally, female immature animals known to ovulate 3 days after PMS injection were treated concomitantly with either primary or catecholestrogen-antibody preparations. Whereas the primary estrogen antibody significantly blocked ovulation, the 2- and 4-hydroxyestrogen antibodies were ineffective. If, however, PMS and estrogen-antibody treated animals were supplemented with 4-hydroxyestrogens, ovulations could be restored. Thereby, it was inferred that peripheral 4-hydroxyestrogens, though not essential for the physiology of reproduction, can completely replace the physiologically essential peripheral estradiol at central target sites.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 45 (1982), S. 217-229 
    ISSN: 1432-1106
    Keywords: Rat ; Thalamic reticular nucleus ; Lateral geniculate nucleus ; Electrophysiology ; HRP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electrophysiological and neuroanatomical techniques have been used to study the properties of cells in the reticular nucleus of the thalamus (RNT) responsive to photic stimuli. In the rat these cells are located in a discrete region of the nucleus lying immediately rostral to the dorsal lateral geniculate nucleus (LGNd), where the visual field is represented in a retinotopic fashion. After injections of horseradish peroxidase (HRP) into this area, neurones labelled with reaction product were found in the LGNd and not in other thalamic relay nuclei. After HRP injections into the LGNd, labelled RNT cells were found only within the region which contains neurones responsive to photic stimuli. These observations suggest that there is a precise reciprocal relation between the two areas. Studies and comparisons of the responses of relay cells (P cells) in LGNd and cells in RNT to electrical shocks lead us to conclude that RNT cells receive their excitation mainly via those relay cells in LGNd which are themselves excited by fast-conducting retinal ganglion cell axons. Such cells in LGNd have phasic responses and concentric receptive fields while RNT cells have phasic responses and on/off fields and a comparison of the receptive field sizes of P cells and RNT cells suggests that only a small number of LGNd relay cells converge on to each RNT cell. Further, although a particular functional class of relay cells in LGNd (Y-type) is shown to provide the major input to visually responsive RNT cells, both Y type and W type relay cells are subject to their inhibitory control. These results furnish evidence that cells in the RNT have an important role in modulating the flow of visual information from the LGNd to cortex.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 47 (1982), S. 270-276 
    ISSN: 1432-1106
    Keywords: Rat ; Turning ; Parafascicular nucleus ; Fasciculus retroflexus ; Apomorphine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Apomorphine, 2 mg/kg i.p., produced ipsilateral turning in rats with unilateral lesions in the parafascicular nucleus of the thalamus. The effect was completely blocked by the administration of haloperidol, 0.3 mg/kg i.p. There were no asymmetries by the lesions alone or after administration of haloperidol, 2 mg/kg i.p. to lesioned animals. In control experiments apomorphine produced a marked contralateral turning in animals with unilateral degeneration of the fasciculus retroflexus.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 78 (1982), S. 225-229 
    ISSN: 1432-2072
    Keywords: Diazepam ; Prenatal treatment ; Development ; Discrimination ; Motor behavior ; Learning retention ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In the present study the effects of chronic treatment of pregnant rats with diazepam on the physical and behavioral development of their offspring were investigated. Rats that were diazepam-exposed prenatally were compared to age-matched controls in terms of the following: number of littermates; birth weight and weight gain until weaning; motor development and coordination; simple motor learning; open field activity; performance on learning tasks of varving complexity; retention of these tasks. Nulliparous Wistar rats were injected s.c. for 16 days of their pregnancy with either 2.5, 5, or 10 mg/kg diazepam or an equal volume of vehicle. Prenatal diazepam treatment did not alter litter size, birth weight, or the righting reflex, but seemed to retard early motor development transiently. Diazepam pups showed longer latencies and less rearing in the open field. There were no differences between animals exposed to drug and vehicle in simple motor learning or in acquiring a simple successive discrimination task. However, there were significant dosedependent differences on a complex six-choice simultaneous discrimination learning task, the diazepam-exposed rats making more errors and taking more time to reach the goal. A significant difference was seen again between diazepam-and vehicle-exposed rats on the retention test 10 days later. The results indicate that diazepam administered to pregnant rats has long-range effects on the behavior of the offspring, some becoming manifest even in maturity.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 399 (1982), S. 61-78 
    ISSN: 1432-2307
    Keywords: Chordoid sarcoma ; Chondrosarcoma ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Evaluation of a series of 12 chordoid sarcomas suggests that there is a wider range of histological features in this entity then previously appreciated. Six of the lesions had a typical tumor cell organization and a mixture of cellular and myxoid stromal components, while the remaining cases were atypical because of a more solid growth pattern. Four of the 12 cases, that included both typically myxoid and more cellular examples, had small foci with hyalinized stroma segragating individual or small groups of tumor cells with and without lacunar spaces. Two atypical cases revealed more extensive and obvious chondrocytic differentiation in recurrent or metastatic lesions and in one of these, the histological pattern was that of mesenchymal chondrosarcoma. Ultrastructural examination of three cases revealed fine structural features of both the tumor cell population and extracellular matrix compatible with chondrocytic differentiation. Results of light and electron microscopy of this series of chordoid sarcoma add further support for categorizing this tumor with other malignant chondrocytic neoplasms. It is probable that chordoid sarcoma and extraskeletal myxoid chondrosarcoma represent the same entity and that this lesion has a close histogenetic relationship to mesenchymal chondrosarcoma.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 395 (1982), S. 59-68 
    ISSN: 1432-2307
    Keywords: Adenohypophysis ; Electron microscopy ; Growth hormone ; Immunocytology ; Pituitary adenoma ; Thyroid-stimulating hormone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A pituitary adenoma removed by surgery from a 22-year-old man was studied by histology, immunocytology, transmission electron microscopy and immunoelectron microscopy. Clinically, the patient had acromegaly and euthyroidism with elevated blood GH concentrations. Blood TSH and T4 levels were within the normal range. Histologically, the adenoma was chromophobic and exhibited no PAS, lead hematoxylin, aldehyde thionin or Grimelius silver positivity. By the immunoperoxidase technique GH, β-TSH and α-subunit but no PRL, ACTH, α-endorphin, β-FSH or β-LH were demonstrated in the adenoma cells. Electron microscopy revealed adenoma cells which were similar to TSH cells and showed no resemblance to GH cells of nontumorous pituitaries or GH-secreting tumors. Immunoelectron microscopy demonstrated GH and β-TSH in the secretory granules. It is concluded that pituitary adenomas composed of TSH-like cells may secrete GH, resulting in acromegaly. Production of GH by adenomatous TSH cells cannot be explained on the basis of the one cell- one hormone theory. The question is raised whether bihormonal or multihormonal clones, capable of synthesizing more than one hormone, exist in the human pituitary. These cells are apparently dormant under normal conditions, but in the course of neoplastic transformation may undergo functional dedifferentiation and acquire the ability to produce two or more different hormones.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 395 (1982), S. 133-144 
    ISSN: 1432-2307
    Keywords: Endothelium ; Permeability ; Electron microscopy ; Electrolytes ; Silver
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The significance of endothelial “silver lines” was studied by TEM in rat aortas after perfusion with glutaraldehyde followed by silver nitrate. Standard TEM technique proved unsatisfactory (coarse silver granules, imprecise localization, artefacts). Exposure of the silver-treated aortas to photographic fixer markedly improved the image of the deposits leaving fine, stable, uniform “residual granules” about 100 Å in diameter. Most of these granules were localized along the intercellular junctions; they also tended to pool in the basement membrane beneath each junction. This image suggests that the Ag+ ions pass through the junction, and react with its contents as well as with the basement membrane beyond it. A scheme is proposed to explain the reaction of Ag+ ions with anions and negatively charged radicals within the junction. It is concluded that the “silver lines” represent not only a histochemical effect, but also the visualization of a transendothelial electrolyte pathway.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 395 (1982), S. 181-199 
    ISSN: 1432-2307
    Keywords: Lung disease ; Electron microscopy ; Interstitial pneumonia ; Fibrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary This report describes the ultrastructural findings in 37 patients who underwent open lung biopsy which yielded diagnoses of fibrosing alveolitis. A spectrum of lesions are categorized for the capillary endothelium and its basement membrane, the interstitial space and its fibrocellular components, and the alveolar epithelium and its basement membrane. The findings typify the different pulmonary cellular reactions to injury. Evidence for cellular regeneration and death in both epithelial and endothelial cell populations include atypical epithelial cell proliferation, capillary basement membrane multilamination, decrease in capillary lumen size and prominent pericytic ensheathment of pulmonary capillaries. Within the interstitium of the lung, proliferation of collagen and elastic fibers are documented, but in addition, abundant myofibroblasts and smooth muscle cells are present. No ultrastructural evidence of immune complex deposition was found in this study. The morphologic findings of fibrosing alveolitis further support the widespread concept that the lung responds to various injuries in a similar manner and undergoes a common reparative response regardless of etiology.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 396 (1982), S. 91-102 
    ISSN: 1432-2307
    Keywords: Primary gallblader sarcoma ; Electron microscopy ; Histopathology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Six Swedish cases of primary sarcoma of the gallbladder from the period 1958–1973 and 1 case from 1975 were studied by light and electron microscopy. The literature was reviewed for the period after 1970. Ultrastructural features of sarcoma were investigated in order to exclude poorly differentiated carcinoma. One case was considered to be an embryonal rhabdomyosarcoma, three cases leiomyosarcoma and two were diagnosed as fibrosarcoma. One case, diagnosed as sarcoma of the gallbladder by light microscopy, was omitted because electron microscopical examination revealed a squamous cell carcinoma.
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  • 13
    ISSN: 1432-2307
    Keywords: Human malignant cells ; K-562 cell line ; Vascular arrest ; Endothelial attrition ; Extravasation ; Nude and lasat mice ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphological aspects of the arrest and extravasation of malignant cells of human origin (K-562 cell line) in the lungs of athymic (nude) and asplenic-athymic (lasat) mice were studied by electron microscopy examination of serial sections. The specimens were obtained at sequential stages after the sc inoculation into newborn mice of 107 malignant cells. K-562 cells (105) were also injected iv into control groups of nude and lasat mice to assess the influence of the route of inoculation on the in vivo behavior of K-562 cells. Our results demonstrated that K-562 cells were arrested and proliferated within the pulmonary capillaries without the participation of platelets or fibrin. The neoplastic cells extravasated by attrition and penetration of the endothelium (rather than by diapedesis) and continued to proliferate in the interstitial tissue of the lung, developing into neoplastic nodules. Following iv injection, K-562 cells induced the formation of platelet-tumor cell aggregates within the pulmonary capillaries. However, under these conditions, the neoplastic cells did not adhere to the endothelium nor did they proliferate or extravasate. These aggregates were flushed out by the circulation, restoring the permeability of the capillaries.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 396 (1982), S. 291-301 
    ISSN: 1432-2307
    Keywords: Electron microscopy ; Bladder neoplasms ; Measurement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Bladder tissues from 3 groups of patients were examined, using the light and electron microscopes (LM and TEM). One group of patients had a history of well-differentiated papillary transitional cell carcinomas and specimens were taken from cystoscopically normal areas. In a second group frank papillary carcinoma was biopsied. Finally, patients with no history of urothelial tumours and a normal cystoscopic appearance were biopsied during investigations for various benign conditions and these served as controls. In tissues from the first two groups certain differences were seen when these were compared to the controls and the frequency of these was significant. Light microscopic examination of 0.5 μ toluidine blue stained sections revealed an increased number of immature, small dark cells in the superficial layer of the epithelium (P〈0.001). Electron microscopic examination showed that in place of the characteristic asymmetric unit membrane of mature superficial cells, the surface was frequently covered with microvilli and the junctional complexes were often atypical. There was an increased number of abnormalities in the basal lamina (P〈0.001). These features were seen in the absence of cystoscopic and light microscopic changes in three out of eight patients with a history of tumours. It is, therefore, suggested that these are the earliest detectable morphological abnormalities in the pre-neoplastic urothelium.
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  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Virchows Archiv 397 (1982), S. 17-27 
    ISSN: 1432-2307
    Keywords: Ovarian tumor ; Hilus cell tumor ; Leydig cell tumor ; Virilism ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of virilizing ovarian hilus cell tumor (Leydig-cell tumor) in a 37 year old female was studied by light and electron microscopy. The ultrastructural features of this rare and almost allways benign tumor are compared with those reported in the literature and with findings in normal and neoplastic interstitial cells of the testis. Tubulovesicular hyperplasia and formation of whorl structures of the endoplasmatic reticulum together with the presence of exocytosis vesicles on the cell surface may be the morphological manifestation of endocrine activity of the tumor. The identity of ultrastructural and optical diffraction characteristics of the crystal inclusions in both cells (hilar and testicular interstitial) favours the assumption of an homology of both cells and their neoplasms.
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  • 16
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    Electronic Resource
    Springer
    Virchows Archiv 397 (1982), S. 93-101 
    ISSN: 1432-2307
    Keywords: Biphasic synovial sarcoma ; Semitendinosus bursa ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In previous studies, the origin of synovial sarcoma directly from synovium has not been satisfactorily established. This case report describes the light and electron microscopic features of a biphasic synovial sarcoma occurring within the popliteal fossa. At surgery, a cystic mass was identified in relationship to the semitendinosus tendon at the anatomical site of the semitendinosus bursa. The tumour originated from the inner surface of the bursa as multiple papillary projections with no evidence of extension beyond the capsule of the bursa. Portions of the synovial surface were hyperplastic but otherwise normal. The findings indicate that biphasic synovial sarcoma can arise directly from synovium and support the hypothesis of a mesenchymal histogenesis for this tumour.
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  • 17
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    Virchows Archiv 397 (1982), S. 335-345 
    ISSN: 1432-2307
    Keywords: Bladder neoplasm ; Mesonephric origin ; Urethral diverticulum ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A case of a rare tumor arising in a diverticulum of the urethra was studied. Light microscopy revealed the typical structures of mesonephric tumor with obvious infiltration of the muscularis. Electron microscopic appearance indicated that the tumor cells were immature and not totally characteristic of any tissue of origin. Apart from appearances suggesting rapid growth, cellular inclusions of various appearance were found.
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  • 18
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    Psychopharmacology 76 (1982), S. 66-69 
    ISSN: 1432-2072
    Keywords: Experimental epilepsy ; Kindling ; Amygdala ; Acetylcholine ; Choline uptake ; Atropine ; Muscarinic receptors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of atropine on kindling the amygdala of rats was tested by administering the drug in a dose of 25 mg/kg 1 h before each stimulus was applied. Rats tested with atropine kindled at the same rate as saline-treated controls. Cholinergic activity in the amygdala of rats was assessed, 4 weeks after the completion of kindling, by measuring both muscarinic receptor numbers and sodium-dependent high affinity choline uptake in tissue homogenates. There was no change in either of these parameters attributable to kindling. These results suggest that changes in the cholinergic system are not fundamental either to the development or the maintenance of kindling in the rat amygdala.
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  • 19
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    Psychopharmacology 76 (1982), S. 114-117 
    ISSN: 1432-2072
    Keywords: Brain ; β-Adrenoceptors ; Serotonin synthesis ; Metoprolol ; ICI 118,551 ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were treated subchronically (14 days) or acutely (single dose) with the β1-selective adrenoceptor antagonist metoprolol or the β2-selective adrenoceptor antagonist ICI 118,551. Metoprolol (350 mg/kg/day for 14 days, orally) significantly reduced the 5-hydroxytryptophan (5-HTP) accumulation when measured 30 min after inhibition of L-amino acid decarboxylase by NSD 1015 (100 mg/kg IP) in the limbic forebrain, the corpus striatum, the cerebral cortex, the brain stem, and in the cerebellum. ICI 118,551 (0.5 mg/kg, twice daily for 14 days, SC) also significantly reduced the 5-HTP accumulation in the same brain regions except in the corpus striatum and the brain stem. Simultaneously assayed tryptophan levels were largely unaffected. Thus sustained β-adrenoceptor blockade causes a decrease in the in vivo rate of tryptophan hydroxylation in various rat brain regions. The subchronic treatments with metoprolol or ICI 118,551 also significantly reduced the endogenous levels of 5-hydroxytryptamine (5-HT) in the various rat brain regions studied. Acute treatment with either metoprolol (2 mg/kg SC) or ICI 118,551 (0.5 mg/kg SC) did not affect the 5-HTP accumulation or the endogenous 5-HT levels in the brain regions studied. This inhibitory effect on brain 5-HT systems produced by sustained β-adrenoceptor blockade may be of significance both for the long-term cardiovascular action and for occasional neuropsychiatric side effects during β-blocking therapy.
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  • 20
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    Psychopharmacology 76 (1982), S. 160-162 
    ISSN: 1432-2072
    Keywords: Nicotine ; Withdrawal ; Plasma corticosterone ; Stress ; Adaptation ; 5-Hydroxytryptamine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of chronic nicotine administration (0.4 mg/kg for 40 days) and its withdrawal on the adrenocortical response to acute and repeated exposure to stress have been examined and related to changes in brain 5-hydroxyindole levels. No significant effects on the response to acute stress were observed. Repeated exposure to the stressful procedure resulted in complete adaptation of the adrenocortical response and the development of a significant (P〈0.01) positive correlation between the plasma corticosterone and hippocampal 5-HT concentrations. In nicotine-treated rats, complete adaptation did not occur and the plasma corticosterone showed a significant (P〈0.05) negative correlation with hippocampal 5-HT. Nicotine withdrawal was not associated with any reduction in plasma corticosterone, but did abolish its relationship with hippocampal 5-HT.
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  • 21
    ISSN: 1432-2072
    Keywords: Turning behaviour ; Brain lesions ; 5-MeODMT ; Dopaminergic system ; Dopamine release ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The turning behaviour induced by 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) has been investigated in rats with lesions of the dorsal raphé nucleus (DRN). 5-MeODMT caused a dose-related contralateral turning in rats with 5,7-dihydroxytrypamine (5,7-DHT) lesions of the substantia nigra and a similar effect was observed in DRN-lesioned rats. In contrast, a dose-related ipsilateral turning was observed when 5-MeODMT was injected into rats with 5,7-DHT lesions of the striatum. These results suggest that the effects of 5-MeODMT in DRN-lesioned rats are mediated via the substantia nigra. The contralateral turning induced by 5-MeODMT in rats with a 5,7-DHT lesion of the DRN was significantly reduced when a second 6-hydroxydopamine lesion was placed in the striatum, but not when it was placed in the nucleus accumbens. Thus the nigrostriatal dopaminergic system seems to be involved in 5-MeODMT-induced turning. The release of tritium from slices of substantia nigra previously labelled with [3H]-dopamine was inhibited by 5-MeODMT (10-7 to 10-5 M) and this effect was blocked by methysergide in a concentration-related manner. Tetrodotoxin (10-7M) failed to antagonise 5-MeODMT. These results suggest that 5-MeODMT can inhibit dopamine release from nigral dendrites, which could in turn enhance nigrostriatal activity by reducing the auto-inhibitory actions of dopamine, thereby causing contralateral turning in DRN-lesioned rats.
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  • 22
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    Psychopharmacology 78 (1982), S. 277-281 
    ISSN: 1432-2072
    Keywords: Conditioned taste aversion ; Scopolamine ; Prochlorperazine ; Lithium ; Amphetamine ; Morphine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two antiemetic drugs were tested on the expression of taste aversions previously conditioned in rats with lithium, amphetamine or morphine. Neither prochlorperazine nor scopolamine administered prior to testing attenuated established aversions, although both drugs are known to have antiemetic effects in other species. Negative findings were obtained with a range of doses of prochlorperazine and scopolamine, with strong and weak aversions, with one- and two-stimulus tests, in a repeated one-stimulus extinction procedure, with between- and within-group designs and with hooded, albino, male and female rats. The results do not support the widely accepted hypothesis that conditioned nausea mediates conditioned taste aversion.
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  • 23
    ISSN: 1432-2072
    Keywords: Discriminative stimulus ; Diazepam ; Morphine ; Naloxone ; Endorphins ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Male Sprague-Dawley rats were trained in a two-lever food-reinforced procedure to discriminate between the effect of saline and diazepam (2.5 mg/kg). After acquisition of this discrimination, the ability of morphine to generalize, and naloxone to antagonize the diazepam discriminative stimulus was tested. The rats did not generalized the effect of morphine, and naloxone did not antagonize the diazepam discriminative stimulus whether it was given prior or subsequent to diazepam. These data suggest a lack of involvement of endorphins in mediating the discriminative stimulus property of diazepam.
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  • 24
    ISSN: 1432-2072
    Keywords: Seizure threshold ; Ro 15-1788 ; Ro 05-3663 ; Benzodiazepine receptor ; Melatonin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Both the anticonvulsant and sedative effects of diazepam (5 mg/kg) were reversed by subsequent administration of the suggested specific benzodiazepine antagonist Ro 15-1788. In contrast neither the seizure threshold raising or sedative effect of melatonin (200 mg/kg) was reversed by Ro 15-1788. Ro 15-1788 had no effect on the convulsant action of the benzodiazepine Ro 05-3663. These data therefore argue against the suggestion that melatonin produces its sedative and anticonvulsant effects in vivo by interacting with the benzodiazepine receptor, and also strengthens the suggestion that Ro 05-3663 does not act at this site. The use of Ro 15-1788 in demonstrating whether a drug acts in vivo at the benzodiazepine site to produce a pharmacological response is discussed.
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  • 25
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    Psychopharmacology 78 (1982), S. 326-330 
    ISSN: 1432-2072
    Keywords: Morphine withdrawal ; Dopamine ; Lisuride ; N-n-propylnorapomorphine ; Haloperidol ; Sulpiride ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The influence of lisuride on naloxone-induced withdrawal signs (wet shakes, escape attempts) was studied in morphine-dependent rats. Lisuride, injected IP at doses of 12.5 and 25 μg/kg, inhibited wet shakes while not significantly altering escape attempts induced by naloxone (4 mg/kg IP). At higher doses (50 and 100 μg/kg IP), lisuride's inhibitory effect on wet shakes persisted while escape attempts were actually potentiated with respect to control withdrawal rats. Increases in aggressive behavior were seen at all doses, and were dose-related. Haloperidol (0.3 mg/kg IP), administered 40 min before lisuride, did not modify the antagonistic effect on wet shakes, unlike sulpiride (40 mg/kg IP 30 min before lisuride), but at the same time blocked the increase in escape attempts and aggressiveness induced by lisuride. We suggest that lisuride modulates withdrawal signs by stimulation of dopamine receptors in the CNS. The effect of the dopamine mimetic N-n-propylnorapomorphine (NPA) on the same variables is reported as well as the influence of haloperidol on NPA, and a comparison between the effects of the two drugs is made.
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  • 26
    ISSN: 1432-2072
    Keywords: d-Amphetamine ; Feeding ; Locomotion ; Stereotypy ; Striatum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of d-amphetamine over a wide range of doses (0.125–4.0 mg/kg IP) on rat unconditioned behaviour were examined in the presence of food and water (experiment 1), in their absence (experiment 2) and after microinjection (2.0 μg in 0.5 μl) directly into the striatum (experiment 3). In experiment 1 very low doses (0.125 and 0.25 mg/kg) stimulated the intake of food, but not water, and higher doses produced locomotor hyperactivity, rearing, stereotyped sniffing and anorexia. In experiment 2 all doses, including very low doses (0.125 and 0.25 mg/kg), significantly potentiated locomotor activity. In experiment 3, microinjection into the corpus striatum elicited substantial feeding, but not drinking, locomotor activity or stereotyped behaviour. The results suggest that a single graded facilitative mechanism underlies the effects on food intake and other behavioural effects of amphetamine, as implied by a general hypothesis of amphetamine action proposed in the literature, and that these effects may to a large extent by mediated by forebrain dopamine systems.
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  • 27
    ISSN: 1432-2072
    Keywords: Phencyclidine ; d-amphetamine ; Lithium ; Locomotor activity ; Stereotyped behaviors ; Ataxia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract d-Amphetamine and phencyclidine (PCP) have both been reported to produce manic-like sequela in humans, effects that are reportedly antagonized by lithium. To test the hypothesis that the acute effects of these drugs in rats may serve as models of mania, the behaviors, induced by d-amphetamine (3 mg/kg) or PCP (5 mg/kg) were quantified on behavioral rating scales subsequent to chronic dietary pretreatment with lithium carbonate or control diet. On day 14 of pretreatment, PCP-induced stereotyped behaviors and ataxia were potentiated in rats receiving lithium (plasma levels 1.0±0.23 mEq/l). PCP-induced locomotor activity was not affected by lithium pretreatment. Stereotypies and locomotion induced by d-amphetamine were also not significantly affected by lithium pretreatment. These results suggest that neither PCP nor amphetamine administered acutely to rats will be useful models to explore the manic-like symptoms produced by these drugs in humans.
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  • 28
    ISSN: 1432-2072
    Keywords: GABA ; Ventral tegmental area ; Dopamine ; Pictrotoxin ; EOS ; Enkephalin ; Locomotor activity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The spontaneous activity of rats was measured after activation or inhibition of GABA activity in the ventral tegmental area of the midbrain (VTA). Six hours after bilateral injection of ethanolamine-o-sulphate (GABA agonist) into the VTA, the behavioural activation induced either by d-amphetamine (amph) or by bilateral VTA infusion of a long-lasting enkephalin analogue was completely blocked. Bilateral infusion of picrotoxin (GABA antagonist) into the VTA elicited a short-lived (40 min) dose-dependent behavioural activation which was not reduced either by prior specific lesion of the meso-cortico-limbic dopaminergic neurones or by administration of the opiate antagonist naloxone. Moreover, the simultaneous administration of picrotoxin and amph induced complex changes in behaviour which consisted of additive effects during the first 40 min, followed by an inhibition of the activating effect of amph. Our findings indicate that GABA-mediated inhibition involves both dopaminergic and non-dopaminergic neurones within the VTA, and possible implications for human pathology are discussed.
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  • 29
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    Psychopharmacology 78 (1982), S. 85-88 
    ISSN: 1432-2072
    Keywords: Hypothalamus ; Serotonin ; Tryptamine ; Acetylcholine ; Release ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Tryptamine produced a concentration-related inhibition of potassium-evoked release of tritium from slices of rat hypothalamus preloaded with 3H-serotonin. This effect of tryptamine was blocked by a series of serotonin antagonists with a relative order of potency which suggested that tryptamine was acting on a post-junctional serotonin receptor. However, the response to tryptamine was also blocked by tetrodotoxin, indicating that tryptamine may be acting indirectly via the release of a second neurotransmitter. The finding that physostigmine enhanced, whilst atropine antagonised the effect of tryptamine suggests that the second neurotransmitter may be acetylcholine. This possibility is discussed.
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  • 30
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    Psychopharmacology 77 (1982), S. 94-97 
    ISSN: 1432-2072
    Keywords: 3H-imipramine binding site ; Imipramine ; Lithium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The specific high-affinity binding of 3H-imipramine to rat brain membranes was investigated. Five weeks of lithium treatment decreased the number of binding sites, but had no effect on the affinity constants. Long-term imipramine treatment had no effect on the number of binding sites but apparently decreased the affinity. The latter effect was probably due to imipramine remaining in the membrane preparation.
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  • 31
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    Psychopharmacology 77 (1982), S. 98-100 
    ISSN: 1432-2072
    Keywords: l-dopa ; Tryptophan ; Brain concentration ; Isoprenaline ; Carrier transport ; Blood-brain barrier ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract A small dose of isoprenaline or saline was administered intraperitoneally to rats 20 min before the administration of one of the amino acids l-dopa or l-tryptophan. Isoprenaline caused a marked increase in the brain concentration of the administered amino acid. Isoprenaline has previously been shown to cause a decrease in at least some of those plasma amino acids which compete with l-dopa and tryptophan for carrier-mediated transport into the brain. The effect of isoprenaline on the concentrations of dopa and tryptophan in the brain is suggested to be at least partly caused by a change in the relationship between endogeneous and administered amino acids. It is also possible that a direct effect of isoprenaline on the blood-brain barrier transport system contributes to the effect. The reported finding might be of clinical interest in view of the therapeutic importance of aromatic amino acids with a central site of action.
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  • 32
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    Psychopharmacology 77 (1982), S. 124-128 
    ISSN: 1432-2072
    Keywords: Chronic cannabis ; Locomotor activity ; DRL performance ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Chronic oral administration of cannabis extract to rats (daily Δ 9 dose 20 mg/kg) was examined for its residual effect on open field activity and DRL (differential reinforcement of low-rate responding) performance, following a 2–3-month drug-free period. Locomotor activity during the latter part of an open field test was markedly increased in rats previously treated for either 6 months or 3 months with the drug. The same treatments also produced a significant impairment on a DRL-20 task relative to control subjects' performance. These and other findings (impaired maze learning and facilitated two-way shuttle box avoidance) might mean that cannabis produces long-lasting hippocampal, dysfunction in rats.
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  • 33
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    Psychopharmacology 77 (1982), S. 117-123 
    ISSN: 1432-2072
    Keywords: Chronic cannabis ; Learning ; Radial-arm maze ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Chronic oral administration of cannabis extract to rats (daily Δ 9tetrahydrocannabinol dose 20 mg/kg) was examined in three experiments for its residual effect on radialarm maze learning following a 1-month drug-free period. Learning a simple eight-arm maze was significantly impaired in rats treated for either 6 months (Experiment I) or 3 months (Experiment II) with the drug. In Experiment III, animals that received the extract for 3 months exhibited significant learning deficits on a much more difficult 12-arm radial maze. The results demonstrate that the deleterious effects of cannabis on radial-arm maze learning are probably due to a tendency toward increased vigilance and perseveration, possibly combined with an impaired utilization of spatial cues.
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  • 34
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    Psychopharmacology 77 (1982), S. 134-139 
    ISSN: 1432-2072
    Keywords: Animal model ; Rat ; Tardive dyskinesia ; Oral dyskinesia ; Chronic haloperidol ; Neuroleptic ; 6-Hydroxydopamine ; Kainic acid ; Frontal cortex ; Striatum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract After 10–12 weeks of chronic haloperidol administration rats with frontal cortex ablations or lesions induced by intracerebroventricular injection of 6-hydroxydopamine developed vacuous chewing behavior at a fairly stable frequency (bifrontal ablations had 15–20, 6-hydroxy-dopamine lesioned rats 7–12 chewing movements/min). This behavior persisted for 10 weeks after the last injection of haloperidol decanoate. However, rats with frontal cortex lesions developed a low rate of vacuous chewings (4–8 chewings/min) even without haloperidol administration. Bilateral intrastriatal injections of kainic acid in combination with chronic haloperidol administration did not cause chewing movements in excess of unlesioned haloperidol-treated controls. Pharmacological tests of this animal model for tardive dyskinesia (TD) revealed similarities to human TD, but also differences. Dopamine agonists (apomorphine) and antagonists (haloperidol) both lowered chewing behavior analogous to reported effects on TD and so did gabaculine. The cholinergic drugs physostigmine and pilocarpine, however, increased chewing in rats, while anticholinergics (atropine) reduced it, in contrast to reported effects on human TD.
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  • 35
    ISSN: 1432-2072
    Keywords: Locus coeruleus ; Dorsal noradrenergic bundle ; Open-field ; Clonidine ; Prazosin ; Yohimbine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We previously showed in the rat that electrical stimulation of the nucleus locus coeruleus produced, 4 weeks later, a significant increase in the number of α1 and α1 in the cerebral cortex. In a parallel pharmacological study, we tested the effects of small doses of clonidine on the locomotor activity of stimulated rats and implanted but not stimulated animals. In stimulated rats only, clonidine had a dual effect: firstly, sedation 30 min after injection, and secondly, hyperactivity which was observed 24 h after injection. In the present study, using the same behavioral paradigm, we tested the effects of small doses of clonidine on the locomotor activity of three groups of rats: stimulated in the locus coeruleus, lesioned in the dorsal noradrenergic bundle and controls. In stimulated rats injected with clonidine, delayed hyperactivity appeared 24 h after the injection, beginning at the smallest dose used (2.5 μg/kg). This hyperactivity was not due to the stimulation per se, since it did not appear in stimulated rats injected with the vehicle. In rats with dorsal noradrenergic bundle lesions, this delayed hyperactivity was observed only after a high dose (50 μg/kg) of clonidine. In a second experiment, we tested the effect of small doses of prazosin or of yohimbine on the delayed, drug-induced, hyperactivity of stimulated or lesioned rats. In stimulated rats, prazosin (an α1-adrenoceptor antagonist) suppressed the hyperactivity produced by clonidine. Yohimbine (an α2-adrenoceptor antagonist) markedly increased the locomotor activity of stimulated rats injected with vehicle. Likewise, in lesioned rats, prazosin suppressed the hyperactivity produced by a dose of 50 μg/kg of clonidine. These results are interpreted in relation to the possible role of α-adrenoceptors in the regulation of locomotor activity.
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  • 36
    ISSN: 1432-2072
    Keywords: Anxiety ; Punishment ; Conflict ; Chlordiazepoxide ; β-Carboline carboxylic acid ethyl ester ; Ro 15-1788 ; ACTH(4–10) ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The antagonism of the anticonflict effect of chlordiazepoxide (CDP) by β-carboline carboxylic acid ethyl ester (BCCE), Ro 15-1788 and ACTH(4–10) has been evaluated in the Geller-Seifter rat conflict test in which CDP increases punished (conflict), but not unpunished responding. BCCE (0.5–10 μg ICV) produced a dose-dependent reduction in the anticonflict activity of CDP. This was also significantly reduced by Ro 15-1788 (25 mg/kg IP) and a high dose of ACTH(4–10) (5 μg ICV). None of these test compounds had a marked direct effect on punished or unpunished responding in the doses used. These experiments provide further physiological support for the suggestion from binding studies that BCCE and Ro 15-1788 act on benzodiazepine receptors. However, the ability of ACTH(4–10) to reduce the anticonflict effect of CDP may be by some other, possibly opioid, mechanism.
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  • 37
    ISSN: 1432-2072
    Keywords: Benzodiazepines ; Benzodiazepine antagonist ; Ro 15-1788 ; Barbiturates ; Depressants ; Competitive antagonism ; Mouse ; Rat ; Dog ; Squirrel monkey
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract In neurological and behavioral studies in mice, rats, dogs and squirrel monkeys, the imidazobenzodiazepinone Ro 15-1788 acted as a potent benzodiazepine antagonist. The antagonistic activity was both preventive and curative and seen at doses at which no intrinsic effects were detected. It was highly selective in that it acted against CNS effects induced by benzodiazepines but not against those produced by other depressants, such as phenobarbitone, meprobamate, ethanol, and valproate. The onset of action was rapid even after oral administration. Depending on the animal species studied, the antagonistic effects lasted from a few hours to 1 day. The acute and subacute toxicity of Ro 15-1788 was found to be very low. Benzodiazepine-like effects were not seen.
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  • 38
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    Psychopharmacology 76 (1982), S. 48-51 
    ISSN: 1432-2072
    Keywords: Imipramine ; Serum levels of IMI ; Brain levels of IMI ; Tricyclic antidepressants ; Compartmentation of IMI ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Serum and brain levels of the tricyclic antidepressant drug imipramine (IMI) were studied in the rat under a variety of conditions. IV doses (range 1 nmol kg-1 to 15 μmol kg-1, 350 ng–5mg kg-1) and administered 5 min before death, were linearly correlated with IMI levels in serum, frontal cortex, and cerebellum. In this experiment, the highest levels of IMI were achieved in the frontal and occipital cortex and the lowest levels were found in the brain stem. The regional distribution was more even in rats pretreated with thiopental or γ-hydroxybutyric acid, drugs that alter cerebral blood flow. After 20 min or more, tracer amounts of IMI injected IV to IMI-pretreated rats [1 or 17 days, daily dose 2×36 μmol kg-1 (10 mg kg-1), last dose 89 μmol kg-1 (25 mg kg-1), 2–3 h before death] exhibited a distribution pattern in serum and various brain regions similar to that of the unlabeled drug. In the latter experiments, content (per volume) of the tracer or unlabeled IMI was more than 25-fold higher in various brain areas than in serum. It is concluded that despite large differences in drug levels in serum or brain, a close relationship is maintained under the conditions studied.
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  • 39
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    Psychopharmacology 76 (1982), S. 75-78 
    ISSN: 1432-2072
    Keywords: THIP ; GABA ; d-Amphetamine ; Feeding behavior ; Anorexigenic agents ; GABA-receptor ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of 4,5,6,7-tetrahydroisoxazolo-[5,4-c]pyridin-3-ol (THIP) were compared with those of d-amphetamine and GABA in fasted rats. Intravenously-administered THIP produced a dose-dependent decrease in food consumption (ED50≃1.5 mg/kg) by an action that was not reversed by prior subcutaneous or simultaneous intravenous (IV) injection of bicuculline. d-Amphetamine-SO4 also produced a decrease in food consumption in this model (ED50≃0.2 mg/kg, IV). Unlike THIP, GABA (in doses up to 100 mg/kg, IV) did not produce a marked anorexigenic effect. These results provide further evidence that THIP can penetrate the “blood-brain barrier”, and that central GABA-ergic systems are involved in controlling food intake.
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  • 40
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    Psychopharmacology 76 (1982), S. 149-156 
    ISSN: 1432-2072
    Keywords: Drug discrimination ; Drug generalization ; Fentanyl ; Morphine ; Amphetamine ; Nicotine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Different groups of rats were trained to discriminate fentanyl (F) (0.03, 0.02, or 0.01 mg/kg) from saline or to discriminate 0.03 mg/kg fentanyl (F) from alternative stimulus conditions (saline, 0.15 mg/kg nicotine, or 0.01 mg/kg F). When percentage of responses on the drug lever and percentage of time spent responding on the drug lever were used as dependent variables, it was found that training dose and alternative stimulus condition both affected the ED50 and the slope of the F generalization gradient. ED50 and slope values based on group data were not significantly different from values based on individual data. Differences between the results of the first and second 2.5-min period of the extinction test were not significant. ED50 and slope values were unaffected by the preceding training session, except in the group trained to discriminate 0.03 from 0.01 mg/kg F. A lever selection measure showed a significant effect of alternative stimulus condition on ED50 values only. Training dose and alternative stimulus condition also affected the generalization to morphine. Under none of the conditions explored in this study did generalization occur to amphetamine or nicotine. The results are discussed in terms of the relative nature of drug generalization.
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  • 41
    ISSN: 1432-2072
    Keywords: d-Fenfluramine ; Morphine ; Brain serotonin ; Nociception ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of d-fenfluramine and morphine on various nociceptive responses of rats were investigated. Unlike morphine, which inhibited all the responses examined, d-fenfluramine inhibited jumping and paw licking of rats on a hot plate, but did not increase the latency of tail withdrawal from hot water. The effects of d-fenfluramine on both responses on the hot plate were prevented by pretreatment with metergoline, a serotonin antagonist, whereas this pretreatment only reduced the effect of morphine on paw licking. The inhibition of tail withdrawal by morphine was also significantly reduced by metergoline treatment. The results confirm previous findings suggesting a role of serotonin in the mechanism by which morphine inhibits some nociceptive responses in rats. They also show that d-fenfluramine, a selective releaser and uptake inhibitor of serotonin at nerve endings, does not completely reproduce the antinociceptive effects of morphine in this species.
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  • 42
    ISSN: 1432-2072
    Keywords: Gamma-hydroxybutyric acid ; Dopamine ; Stereotyped behaviour ; Food intake ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The administration of gamma-hydroxybutyric acid (GHB) initially causes a temporary “sleep-like” state during which there is an increase in forebrain dopamine levels. The present series of experiments examined whether in the period following the GHB-induced behavioural depression, when accumulated dopamine is dispersed, there is any behavioural evidence of increased dopaminergic activity. The first experiment, in which GHB was injected directly into the cerebral ventricles, demonstrated that in the immediate post-recovery period rats exhibited various forms of stereotyped oral behaviour and stereotyped sniffing. Unexpectedly, it was also observed that if food were present animals preferred to eat. The nature of this feeding response was examined in two further experiments. Firstly, it was shown that in the period following the behavioural depression animals would perform, in a dose-dependent fashion, an operant response which was rewarded by food. Secondly, the GHB-induced increase in feeding was abolished by the pre-treatment of animals with either the dopamine synthesis inhibitor alpha-methyl-p-tyrosine, or the dopamine receptor blocker haloperidol. These data indicate that (i) in the period when it is known that the GHB-induced accumulation of dopamine is dispersing, there is behavioural evidence of increased dopaminergic activity; (ii) the feeding response is not a simple oral reflex; and (iii) in addition to being essential for food intake dopaminergic transmission may play a direct role in the production of feeding.
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  • 43
    ISSN: 1432-2072
    Keywords: Systemic DSP4 ; Two-way avoidance ; Acquisition ; Spontaneous activity ; NA uptake ; Endogenous NA ; Peripheral NA ; Pain sensitivity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract N-2-chloroethyl-N-ethyl-2-bromobenzylamine (DSP4) (50 mg/kg IP), a new selective noradrenaline (NA) neurotoxin, was found to cause a severe impairment of the acquisition of a two-way active avoidance task 1 week following adminsitration, an effect that was blocked by the selective NA uptake inhibitor desipramine. In a second experiment, systemically injected 6-OHDA (2×30 mg/kg IP) was not found to cause any avoidance impairment, althogh its effects upon peripheral NA were still evident 21 days after administration: The peripheral NA depletion caused by DSP4 almost disappeared 14 days after injection. In a third experiment, the avoidance impairment induced by DSP4 was produced even 10 weeks after treatment. Data from both the shuttlebox experiment and an activity box experiment suggest that the acquisition impairment is not readily explained on the basis of some deficit in spontaneous behavior or an altered perception of pain. The present data suggest that the effect of DSP4 upon active avoidance asquisition is mediated via central, and not peripheral NA neurons.
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  • 44
    ISSN: 1432-2072
    Keywords: Atropine ; Scopolamine ; Cholinergic mechanisms ; Hippocampal complex ; Learning ; Memory ; Passive avoidance ; Ontogeny ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Passive avoidance learning was significantly impaired by atropine (5 mg/kg, IP) or scopolamine (0.5 mg/kg), but not by methyl-atropine (5 mg/kg) or methyl-scopolamine (0.5 mg/kg), from postnatal day 15 on. In contrast, an improvement was observed, not significant at 11 days and significant at 13 days, probably due to nonspecific effects. Retention of the response increased from 6 h at 13 days, to 24 h at 17 days. In treated rats, retention was abolished at 13 and 15 days, and impaired at 17 and 20 days. Acquisition of the response was also significantly impaired by bilateral injections of atropine (1, 5, and 20 μg) into the posteroventral hippocampo-entorhinal (VHE) area, from day 15 on. Concomitantly, extinction was accelerated. At 14 days, atropine had no influence. At 13 days, a facilitatory action was observed, with better acquisition and greater resistance to extinction, possibly linked to affective changes. The results conform that central muscarinic cholinergic mechanisms are involved in passive avoidance learning from postnatal day 15 on, and demonstrate that some pathways of this system are located in the VHE area, become efficient at 15 days, and improve markedly between 17 and 18 days.
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  • 45
    ISSN: 1432-2072
    Keywords: Substantia nigra ; Muscimol ; Oral stereotypy ; Haloperidol ; Collicular lesions ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract It has been suggested that the GABAergic striatonigral projection may form part of the efferent pathway responsible for the expression of dopamine-related oral behaviour. Consistent with this suggestion are reports that bilateral injection of the GABA agonist muscimol can produce stereotyped gnawing and biting. We report here two experiments on this effect: (1) A dose of the dopamine receptor blocker haloperidol (0.4 mg/kg), which effectively antagonised oral stereotypy induced by systemically administered apomorphine or intranigral carbachol, had no effect on either the latency or the intensity of the gnawing produced by intranigral muscimol (1 mM); (2) large lesions involving the superior colliculus which effectively suppressed the oral stereotypy induced by 8mg/kg apomorphine completely abolished the gnawing induced by intranigral injection of muscimol. Collicular lesions suppressed both the gnawing which occurred spontaneously and that elicited by a perioral probe. These findings are consistent with the view that the substantia nigra is a relay station between the caudate nucleus and the superior colliculus in an efferent pathway mediating dopamine-related oral behaviour. In addition, they raise the possibility that such behaviour is produced by the sensitisation of a collicular-mediated perioral reflex.
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  • 46
    ISSN: 1432-2072
    Keywords: Rolipram ; Phosphodiesterase inhibitors ; Cyclic nucleotides ; Locomotor activity ; Rectal temperature ; Forepaw shaking ; Grooming ; Head twitches ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The significance of a characteristic symptomatology (hypothermia, hypoactivity, forepaw shaking, grooming, head twitches) as a potential in vivo correlate of enhanced availability of brain adenosine cyclic 3′,5′-monophosphate (cAMP) was examined in rats following systemic administration of various doses of dibutyryladenosine cAMP (dBcAMP) or of the phosphodiesterase (PDE) inhibitors rolipram, Ro 20-1724, ICI 63-197, isobutylmethylxanthine (IBMX), theophylline, cartazolate, and papaverine. The various PDE inhibitors could be assigned to three groups according to the pattern of behavioral alterations they induced. Rolipram, Ro 20-1724, and ICI 63-197 (group 1) caused hypothermia, hypoactivity, forepaw shaking, grooming, and head twitches. All behavioral effects were mimicked by dBcAMP but not dBcGMP. The order of potency and effective dosage range to induce the behavioral alterations were, in descending order, rolipram (0.09–1453 μmol/kg IP), ICI 63-197 (0.48–119 μmol/kg IP), Ro 20-1724 (5.6-1438 μmol/kg IP), corresponding with the recently reported efficacy of the drugs to elevate rat brain cAMP in vivo. Comparatively high doses of the alkylxanthine PDE inhibitors IBMX and theophylline (group 2) caused hypothermia, forepaw shaking, grooming, and head twitches concomitantly with a decline of the motor stimulatory effect, suggesting enhanced availability of brain cAMP. The order of potency and the effective dosage range to induce the behavioral alterations were, in descending order, IBMX (28.1–113 μmol/kg IP) and theophylline (139–555 μmol/kg IP). The third group, papaverine (295–1179 μmol/kg IP) and cartazolate (21.5–345 μmol/kg IP), caused only hypothermia and hypoactivity. The differences in the behavioral pattern of the two latter groups of compounds in comparison with dBcAMP and the selective cAMP PDE inhibitors are discussed with regard to their additional interference with adenosine actions besides their nonselective PDE inhibitory action.
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  • 47
    ISSN: 1432-2072
    Keywords: α2 Receptors ; Noradrenergic receptors ; Receptor sensitivity ; Yohimbine ; Clonidine ; Tricyclic antidepressant ; Imipramine ; Growth hormone ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The α-adrenergic mechanisms exert a stimulatory influence on the secretion of growth hormone (GH) in the rat. In the present study the α receptors involved in GH regulation were characterized with respect to subtype. It was also investigated whether the GH response to α receptor agonists can be utilized to assess changes in the responsiveness of central α receptors. The experiments were performed on rats with implanted intra-aortic cannulae allowing frequent blood sampling from freely moving animals. Plasma GH was determined by radioimmunoassay. Reserpine (10 mg/kg) caused a suppression of the normal pulsatile secretory pattern of GH. The α receptor agonist clonidine (CLON) given to reserpine-pretreated animals induced a dose-dependent increase in plasma GH. The effect of CLON (0.2 mg/kg) was prevented by pretreatment with the α2 receptor antagonist yohimbine (3 mg/kg), but not by the α1 receptor antagonist phenoxybenzamine (10 mg/kg). Chronic pretreatment with CLON or imipramine, either of which can be expected to produce a reduced sensitivity of central α2 receptors, resulted in reduced GH responses to CLON. On the other hand, chronic treatment with yohimbine, which should cause denervation supersensitivity of α2 receptors, led to enhanced GH responses to CLON. The results indicate that GH release in the rat is stimulated by postsynaptic α2 receptors. They also suggest that the GH response to CLON can be used as a valid in vivo model reflecting decreased, as well as increased responsiveness of this type of receptor.
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  • 48
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    Psychopharmacology 77 (1982), S. 348-355 
    ISSN: 1432-2072
    Keywords: Brain ; Lithium ; Drug-levels ; Glucose ; Glycolysis ; Krebs cycle ; Metabolism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of lithium on several brain energy metabolites were investigated in rats. Lithium was administered by three alternative routes: 1) in food, 2) via IP injection, or 3) intracisternally via the suboccipital route. Lithium given in food induced permanent changes, mainly in glycolytic processes and in glycogen content. Lithium injected IP induced, in addition, several changes which depended on the increase in brain lithium concentration following injection of lithium. These changes in brain metabolites disappeared as brain lithium concentration stabilized. Intracisternal injection of lithium produced brain lithium concentrations between 1 and 2 mmoles/kg wet wt., with a mean of about 1.6 mmoles/kg wet wt. Lithium concentrations below about 1.6 mmoles/kg wet wt. induced changes in brain metabolites which were similar to the changes seen after IP injection of lithium. Lithium concentrations above about 1.6 mmoles/kg wet wt. induced changes in several brain metabolites which were at variance with the changes induced by lower lithium concentrations. These changes were in many respects similar to changes in brain metabolites seen in rats exposed to convulsive treatment. It is hypothesized that such metabolic changes during lithium treatment, in discrete areas of the brain with higher concentration of lithium, e.g., hypothalamus, might be related to the prophylactic effect of lithium treatment in man.
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  • 49
    ISSN: 1432-2072
    Keywords: Neural development ; Brain amines ; Prenatal administration ; Amitriptyline ; Amphetamine ; Locomotor activity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract d-Amphetamine and amitriptyline (AT) were administered daily to female rats from day 7 of pregnancy until birth of the litters. Changes in the concentration of the biogenic amines, some of their metabolites, GABA, and the activities of glutamate decarboxylase, acetylcholinesterase (AChE), and choline acetyltransferase were determined in the whole brain of the offspring. The offspring of the amphetamine-treated rats showed a marked increase in serotonin concentration and that of its metabolite on postnatal day 1. Changes in the concentration of GABA were apparent on days 15 and 21 and were inversely correlated with changes in the activity of the synthesizing enzyme: Choline acetyltransferase and AChE activities were also increased at this time. Changes in neurotransmitter metabolism were not so evident in the offspring of rats treated with AT. The locomotor activity of the 8-, 15-, and 21-day offspring was also assessed. The offspring of the amphetamine-treated rats showed enhanced locomotor activity initially, but the activity decreased relative to the age-matched controls in the 21-day group. Offspring from the AT-treated group showed reduced locomotor activity.
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  • 50
    ISSN: 1432-2072
    Keywords: Drug discrimination ; Ethylketocyclazocine ; Bremazocine ; Nalorphine ; Pentazocine ; Buprenorphine ; Etorphine ; Dextrorphan ; Phencyclidine ; Ketamine ; Haloperidol ; Diazepam ; Pentobarbital ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to evaluate the discriminative stimulus properties of some narcotic and nonnarcotic drugs in rats trained to discriminate the effect of the proposed opiate ϰ-receptor agonists ethylketocyclazocine and bremazocine. Male Sprague-Dawley rats were trained in a two-lever food-reinforced paradigm to discriminate between the effect of ethylketocyclazocine (0.32 mg/kg) or bremazocine (0.04 mg/kg) and saline. Both groups of trained rats showed dose-dependent generalization to the effect of the proposed ϰ-agonist MRZ-2033 and some animals generalized the effect of nalophine and pentazocine. Some ethylketocyclazocine — but no bremazocine — trained rats generalized the effect of buprenorphine. The effect of dextrorphan, phencyclidine, and ketamine was generalized by some bremazocine-, but no ethylketocyclazocine-trained rats. Neither group of rats generalized the effect of etorphine, haloperidol, diazepam, or pentobarbital. These data suggest the usefulness of this procedure to evaluate the ϰ-like properties of opioid drugs.
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  • 51
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    Psychopharmacology 78 (1982), S. 190-191 
    ISSN: 1432-2072
    Keywords: Electroconvulsive shock ; β-Adrenergic receptors ; Lithium ; Chronic treatment ; Depression ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Electroconvulsive shock (ECS) reduces the number of rat cortical β-adrenergic receptors. Lithium has been reported in several systems to prevent receptor changes induced by other agents. However, the present experiment reports that chronic lithium does not prevent the reduction in dihydroalprenolol binding induced by ten daily ECS treatments.
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  • 52
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    Psychopharmacology 77 (1982), S. 268-271 
    ISSN: 1432-2072
    Keywords: Radial maze ; Working memory ; Physostigmine ; Amphetamine ; Scopolamine ; Apomorphine ; Piracetam ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effect of physostigmine (0.2 mg/kg), scopolamine (0.1 mg/kg), d,l-amphetamine (1 mg/kg), apomorphine (0.05 mg/kg), and piracetam (100 mg/kg) on working memory was examined in 12 rats that were highly overtrained in the radial maze. In experiment 1, drugs administered 10 min before the trial did not worsen performance of rats in the 12-arm maze. In experiment 2, insertion of a 5-min delay between the sixth and seventh choices increased the number of errors over choices 7–12. Performance was unaffected by pretreatment with physostigmine or apomorphine, but was significantly impaired by scopolamine, amphetamine, and piracetam. In experiment 3, performed in a 24-arm maze, the number of errors and trial duration increased, but performance was not decreased by amphetamine or piracetam. It is concluded that the uninterrupted radial maze task is relatively resistant to pharmacological disruption, but that scopolamine, amphetamine, and piracetam enhance the effect of stimuli interfering with the storage of spatial information over delays.
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  • 53
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    Psychopharmacology 78 (1982), S. 234-238 
    ISSN: 1432-2072
    Keywords: Morphine ; Tolerance ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The development of a differential tolerance to morphine was investigated with respect to the mean effective dose, the threshold dose of tolerance, the degree of tolerance after a fixed dose, and the speed of tolerance loss. The mean effective doses, the threshold doses of tolerance, and the degree of tolerance differed considerably from effect to effect, whereas in all tests tolerance loss remained the same. The mean effective doses were not correlated to threshold doses of tolerance, degree of tolerance, or to the loss of tolerance, but a strong correlation exists between threshold doses of tolerance and degree of tolerance to all effects measured. Consequences of these results upon current theories of tolerance are discussed.
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  • 54
    ISSN: 1433-8580
    Keywords: Simulated altitude, adaptation ; Hypoxia ; Normoxia ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The haemoglobin (Hb), red blood cell count (RBC) and haematocrit (Hct) of 11 male rabbits were measured at weekly intervals during a 5-week exposure period to hypobaric hypoxia (simulated altitude, 4,500 m) and the following 4 weeks after restoring normoxic conditions in a climatic chamber at constant temperature. RBC showed the slowest response, Hct the fastest during adaptation to hypoxia and readaptation to normoxia. The body weight decreased during the 1st week at hypoxia and remained at a reduced level for 2 weeks after the return to normoxia. In female rabbits exposed up to 43 days to hypoxia the heart ventricle quotient (HVQ) (weights of left ventricle + septum/right ventricle) was determined. There was a gradual decrease of HVQ expressing the development of right heart hypertrophy which was not stabilised within the observation period.
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  • 55
    ISSN: 1434-0879
    Keywords: Human ; Bladder urothelium ; Electron microscopy ; Hyperthermia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary An electron microscopic study of normal bladder urothelium of elderly subjects treated by hyperthermic perfusions has shown that the tissue responds, sooner or later, in every instance by desquamation. There is no evidence of cell death prior to desquamation although various organelles undergo structural alterations. Mitochondria are especially prone to suffer varying degrees of damage. A short heat shock has revealed differences in the initial response of the thick and thin regions of bladder urothelium known to occur in elderly subjects. After a long, fractionated treatment, regeneration is evident within 3 daysof the end of treatment, and follow-up biopsies have revealed a hyperplastic urothelium within 10 to 12 weeks. The constituent cells show signs of cytodifferentiation at this time but it remains unknown when an ultrastructurally normal urothelium with characteristic cell layers will be restored. The various treatments in this study suggest that the stem cells in the epithelium are unaffected by the levels of hyperthermia employed and that their unimpaired proliferative capacity ensures regeneration of the urothelium.
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  • 56
    ISSN: 1432-0568
    Keywords: Visceral afferents ; Hypogastric nerve ; Preganglionic sympathetic neurons ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The central projections of visceral primary afferents of the inferior mesenteric plexus and hypogastric nerve of the rat were investigated using the transganglionic transport of horseradish peroxidase (HRP). In addition, the location of the corresponding spinal ganglion cells as well as the preganglionic sympathetic neurons is demonstrated. Labelled afferent axons were found in dorsal roots, dorsal root entry zone (preferentially in its lateral part), in all parts of the tract of Lissauer, and in the dorsolateral funiculus. Preterminal axons and/or terminals were distributed mainly to laminae I, IIa and the nucleus of the dorsolateral funiculus. Fewer afferents reached laminae IIb, III–V and X. Afferent projections are densest at L1 and 2 and the caudal T13, but extend up to T10 rostrally, and at least down to L4 caudally. A few visceral afferents ascend to the nucleus gracilis. The great majority of sensory and preganglionic sympathetic cell bodies is located at levels L1 and 2 bilaterally. A few cells are found in decreasing numbers rostrally up to T11. Preganglionic sympathetic neurons (PSN) are located in nucleus intermediolateralis (IML), n. intercalatus (IC) and n. commissuralis dorsalis (DCN). Axons of DCN and IC neurons run laterally, joining those of IML neurons on their way to the ventral roots. Dendrites of IML neurons ramify in all directions but preferentially to the dorsal horn and dorsolateral funiculus. Dendrites of IC and DCN neurons are distributed mainly mediolaterally, the latter also ventrally around the canalis centralis.
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  • 57
    ISSN: 1432-0568
    Keywords: Anterior pituitary cells ; Mitosis ; Rat ; Immunohistochemistry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Mitotic rates of the six types of immunohistochemically identifiable adenohypophysial cells were histometrically calculated in colchicine-pretrated male rats 5, 17, 30 and 70 days old. Sections were stained with the antisera against rLH, rFSH, rTSH, oGH, rPRL and pACTH1–39. The mitotic growth rate of the anterior pituitary gland at 30 days of age was much higher than at other times. Mitotic growth rates of GH and PRL cells increased with advancing age, while those of ACTH-, TSH- and immunonegative cells decreased with advancing age. LH/FSH cells showed no variation in mitotic growth rate with age. Mitotic cells can be classified into six cell types based on their fine structural properties: (1) agranular cells associated with the folliculo-stellate cells; (2) ambiguous cells with scanty minute secretory granules (50–150 nm in diameter); (3) basophils with a number of small secretory granules (130–200 nm); (4) immature acidophils whose large secretory granules (130–300 nm) are sporadically scattered; (5) acidophils with numerous spherical larger secretory granules (200–300 nm); and (6) prolactin cells with large polymorphic granules. At day 5 there was a high mitotic rate of the agranular and ambiguous cells [types (1) and (2)]; at day 70 a high mitotic rate was found in immature and mature acidophils [types (4) and (5)]. The mitotic rate of basophils (type 3) was high only at day 17 and low at all other times. The mitotic rate of prolactin cells (type 6) showed a slight increment with advancing age. It is concluded that the mitotic rates of the six cell types are age-dependent.
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  • 58
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    Anatomy and embryology 165 (1982), S. 81-95 
    ISSN: 1432-0568
    Keywords: Kidney ; Connecting tubule ; Differentiation ; Growth and development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary At the start of its morphogenesis the tubule of an S-shaped body always attaches to the terminal ampulla of the collecting duct. It remains attached there for some time while the terminal ampulla sprouts toward the renal capsule. The most distal part of the tubule that rises to the ampulla forms the connecting tubule, morphogenically the oldest segment of the tubulus nephroni. When younger S-shaped bodies join the same terminal ampulla, 2 to 3 connecting tubules are temporarily attached side by side to a single ampulla. Soon, however, the connecting tubule of the older nephron shifts its point of attachment away from the ampulla to the connecting tubule of the younger nephron. This process is repeated through successive nephron generations. Thus an arcade develops which at the close of morphogenesis includes the connecting tubules of the 3 to 4 oldest juxtamedullary and midcortical nephrons of the collecting duct and is always situated close to interlobular veins. The connecting tubules of the 2 youngest subcapsular nephrons are not incorporated into arcades, but join directly and permanently the collecting duct. — At the start of histogenesis, the undifferentiated tubule epithelium of the S-shaped body has a uniform structure over its entire length. At the junction of the connecting tubule and the terminal ampulla there is a cytologically sharp boundary between cuboidal, dark-stained connecting-tubule epithelium of the nephron and cylindrical, light-stained ampullary epithelium of the collecting duct. The epithelial differentiation begins in the oldest, juxtamedullary connecting tubules of an arcade and progresses upward to the terminal ampulla, so that immature connecting-tubule epithelium and immature ampullary epithelium are temporarily interposed between mature connecting-tubule epithelium and mature collecting-duct epithelium. The mature epithelium of the connecting tubule stains light, in which respect it behaves like the epithelium of the distal tubule. However, it also contains individual cells that are more strongly basophilic, stain dark and, though of nephrogenic origin, cannot be distinguished from the dark cells of the collecting duct by light microscopy. — Morphogenically and histogenically, the arcade-forming connecting tubules and the subcapsular connecting tubules arise from the nephrogenic blastema.
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  • 59
    ISSN: 1432-0568
    Keywords: Ovary ; Oocyte ; Follicles ; Rat ; Syrian Hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Serial sections of 62 rat ovaries and 66 ovaries from Syrian hamsters (Mesocricetus auratus) have been examined by light microscopy. The relative and absolute percentage of preantral intra-ovarian oocyte release (PIOR) was recorded. PIOR was incomplete when the rupture of the basal membrane was not followed by the release of the oocyte from its preantral follicle into the ovarian stroma; conversely, a PIOR was regarded to the complete if the oocyte was released from the preantral follicle into the adjacent stroma. PIOR occurred in 23% of rat ovaries and in 32% of hamster ovaries; meiosis was not resumed. In rat ovaries the frequency of complete PIOR was 71%; the oocyte disappeared quickly after its release and herniated granulosa cells could invade capillaries. By contrast, incomplete PIOR was prevalent in hamster ovaries (67%); oocytes survived in the interstitial cortical tissue after the disappearance of their granulosa and theca cells (“free oocytes”). It is concluded that PIOR reflects the onset of follicular atresia and that different local factors are probably responsible for species differences.
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  • 60
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    Acta neuropathologica 56 (1982), S. 201-206 
    ISSN: 1432-0533
    Keywords: Muscle end-plates ; Porphyric neuropathy ; Electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Motor end-plates were studied in mice at various intervals after a single injection of a synthetic porphyrin, tetraphenylporphinesulfonate (TPPS). Ultrastructurally, excess accumulation of neurofilaments constituted the earliest abnormality. These were followed by atrophy of many nerve terminals and their separation from the postsynaptic area by interposed separation from the postsynaptic area by interposed Schwann cells. Five to 8 months after the injection some postsynaptic areas showed denervation and atrophy. These progressive changes in the nerve terminals were accompanied by secondary changes in the subneural apparatus. Morphometric analysis revealed marked atrophy of the end-plates and significant swelling of preterminal axons. The present findings are suggestive of partial denervation of muscle, occurring after the injection of a synthetic porphyrin.
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  • 61
    ISSN: 1432-0533
    Keywords: Cytochemistry ; Electron microscopy ; Polyglucosan bodies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A cytochemical procedure for polysaccharides was carried out on a brain biopsy specimen, the thin-section study of which had shown excess glucogen granules and the corpora amylacea variety of polyglucosan bodies. Both granules and amyloid bodies were stained positively in contrast to the remaining structures of the brain tissue which remained unstained. This demonstrates that β-granules as well as filamentous and amorphous components of amyloid bodies are just different aspects of the polysaccharide molecule. Up to now the same kind of cytochemical evidence has been supplied for Lafora bodies of human material and Lafora-like bodies of rat material. The present study on corpora amylacea of human material shows that amyloid. Lafora, and Lafora-like bodies all behave the same way when stained for polysaccharides.
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  • 62
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    Acta neuropathologica 56 (1982), S. 146-150 
    ISSN: 1432-0533
    Keywords: Alzheimer's disease ; Creutzfeldt-Jakob disease ; Spongiform changes ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural study of the cortex of four patients with sporadic or familial AD, of two agematched controls without dementia, and of one normal pressure hydrocephalus, revealed in all the cases in the neuropil only occasional vacuoles which had a morphology similar to those observed in CJD. The degree of spongiform-like changes was, however, far less prominent than in CJD and considered mild in all the cases examined. Moreover, curled fragments of membranes within the vacuoles were not observed. It is suggested that the mild vacuolization of the neuropil occasionally observed in cortical biopsies of AD is a non-specific finding and cannot be considered a neuropathologic link between AD and CJD.
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  • 63
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    Acta neuropathologica 56 (1982), S. 151-156 
    ISSN: 1432-0533
    Keywords: Central neuronal tumor ; Third ventricle tumor ; Synapses ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The authors report two cases of a rare tumor in adults which were inserted on the fornix and caused a frontal syndrome. By light microscopy, the tumors, highly calcified, were composed of small clear cells forming dense areas in a patchy fibrillary stroma. Electron microscopy revealed a striking neuronal differentiation with numerous synapses. These tumors, for which the term neurocytomas was proposed, were compared with the other CNS neuronal tumors described in the literature.
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  • 64
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    Acta neuropathologica 57 (1982), S. 1-6 
    ISSN: 1432-0533
    Keywords: Rat ; Malnutrition ; Protein deprivation ; Peripheral nervous system ; Ultrastructure ; Degeneration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In a previous study the occurrence of nerve fibre degeneration with a distribution as in dying-back neuropathies was described in young rats subjected to severe protein deprivation (Oldfors 1981). In this study the ultrastructural appearance of the degeneration of the nerve fibres at different levels of the longitudinal tail nerves in severely protein-deprived rats has been investigated. Various structural changes were noted, the most common being bands of Büngner indistinguishable from those seen in Wallerian degeneration. In nerve fibres which were less severely affected the most common finding was shrinkage of the axon with concomitant folding of the myelin sheath. Other structural changes included axonal accumulation of 10 nm filaments or mitochondria and other cell organelles, areas of demyelination, and projections of axolemma and Schwann cell membrane into the axon. Signs of axonal regeneration occurred but were infrequent. The degenerative changes seen at various levels of the nerves support the view that the neuropathy is of distal axonal type, but the structural appearance differs from several of the toxic dying-back neuropathies.
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  • 65
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    Acta neuropathologica 57 (1982), S. 7-12 
    ISSN: 1432-0533
    Keywords: Oculopharyngeal muscular dystrophy ; Electron microscopy ; Pectoral and psoas muscles ; Myofibrillar degeneration ; A band fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The pectoral and psoas muscles from a 72-year-old man afflicted with oculopharyngeal muscular dystrophy were processed at autopsy for electron microscopy. The ultrastructural analyses of the pectoral muscle showed myofibrils which exhibited Z line streaming and a general breakdown in the organization of the sarcomere. In addition, some of the myofibrils displayed sites of degeneration at the center of the A band. The changes in the psoas muscles which are distant from the primary myopathic loci of oculopharyngeal muscular dystrophy were more extensive than that seen in the pectoral muscle. Control tissues showed intact myofibrils and little postmortem alteration.
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  • 66
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    Acta neuropathologica 57 (1982), S. 23-36 
    ISSN: 1432-0533
    Keywords: Muscle spindle ; Electron microscopy ; Nerve endings ; Denervation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The nerve endings in muscle spindles from lumbricalis muscles of the hindpaw of the rat were studied by electron microscopy from 10 h to 7 days after section of the sciatic nerve. No sensory endings were found after 5 days and no motor endings after 3 days. Early changes in sensory endings included accumulation of lamellar bodies, mitochondrial swelling or shrinkage, an edematous appearance of the cytoplasm and disruption of membranes. The predominant way of removal was phagocytosis by activated mesenchymal cells; other endings were incorporated into the sarcoplasm as electrondense bodies. Early changes in motor endings included aggregation or swelling of synaptic vesicles, swelling or shrinkage of mitochondria, edematous change of the cytoplasm and disruption of membranes. The predominant way of removal was incorporation into the cytoplasm of adjacent Schwann cells and degradation to phagolysosomes. Sites of removed sensory endings could be identified by basement membrane reduplication, while the intact subsynaptic apparatus of removed motor endings was either loosely covered by Schwann cell processes, or by fibrillar material, or appeared empty. The differences in the removal of motor and sensory endings are explained by the differences in their anatomic structure.
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  • 67
    ISSN: 1432-0533
    Keywords: Radiation effects ; Nervous system ; Drosophila melanogaster ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fruit flies (Drosophila melanogaster) were exposed to high-LET krypton (84Kr) ions at low (4.2 rad) and high (1,584 rad) doses and killed to assess acute (36 h post-exposure) and late (35 days post-exposure) effects in the brain by means of electron microscopy. The main findings were: (a) glycogen granules appeared in the neuroglial compartment 36 h after exposure to either dose and were no longer present in flies killed 35 days later, (b) neuronal alterations (swelling and membrane disruption) were observed 35 days after exposure to both doses, (c) changes in the neuroglia (electron-dense masses of concentrically arranged membranous structures) were seen 35 days after exposure. The data are discussed in relation to previous research in the fruit fly using argon (40Ar) charged particles and to other radiation studies performed in the mammalian brain with the view of using the insect brain as a model for detailed study of radiation effects on neurons, neuroglia, and the neuron-neuroglia unit.
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  • 68
    ISSN: 1432-0533
    Keywords: Ependymoma ; Rat ; Ethylnitrosourea ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Tumors of the central nervous system (CNS) in Sprague-Dawley and Lewis rats were induced transplacentally by a single intraperitoneal (IP) injection of 10–25 mg/kg ethylnitrosourea (ENU) on days 16–20 of gestation. Light-microscopic examination revealed that 22% of these tumors could be diagnosed as ependymomas, anaplastic ependymomas (ependymoblastomas), or mixed tumors revealing both oligodendroglioma and anaplastic ependymoma tissues if the criteria of accepted classifications were followed. Electron-microscopic examination, however, demonstrated that the ependymoma and the anaplastic ependymoma-like tissue in ENU-induced tumors lacked ependymal features, such as basal bodies, cilia, complicated junctional complexes, microvilli, etc. This tissue type was repetitious, always being composed of cells arranged in groups, cords, and rosette-like (pseudorosette) formations. In the pseudorosettes, the cell nuclei were polarized at the periphery and the cytoplasm contained numerous polyribosomes, occasional short microtubules and usually a few small dense-core vesicles. The center of the pseudorosettes showed numerous slender interdigitating processes interconnected by maculae adherens. The tips of these processes showed vesicular degeneration. The cells arranged in groups or cords and perivascular rosettes revealed identical ultrastructure, but they were not polarized. The present findings indicate that the socalled ENU-induced ependymomas and anaplastic ependymomas are not true ependymal tumors, but rather primitive neuroepithelial neoplasms with some features of oligodendroglioma.
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  • 69
    ISSN: 1432-0533
    Keywords: Architectonic anomalies ; Rat ; Telencephalon ; Micrencephaly ; Methylazoxymethanol acetate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Graded degrees of micrencephaly were produced in the progeny of rats given 0, 14, 22, or 30 mg methylazoxymethanol acetate (MAM Ac) per Kg b.wt. on gestation day (GD) 15. Brains of animals from five litters were examined at each dose level. Golgi-Cox-stained sections prepared from brains of progeny of rats given 25 mg MAM Ac/kg on GD 15 were also evaluated for four micrencephalic and four control animals. Each increase in dosage of MAM Ac resulted in significantly greater loss in brain weight in the progeny. The largest effect was on the telencephalon. In the low dose group the telencephalon, though noticeably smaller, was structurally normal. The two higher doses resulted in easily visualized neuropathologic lesions in both the cerebral cortex and hippocampus. The external layers of the cerebral cortex were most severely affected. Layers V and VI were much better preserved but measurements on pyramidal cells in layer VI in the Golgi-Cox-stained sections showed them to have significantly fewer dendrites and spines than the normal animals. In addition to an intrinsic disorganization of the neocortex, periventricular nodular heterotopias and hippocampal ectopias were common. All the structural anomalies were most severe at the highest dose, though they were also readily apparent at the intermediate dose. The findings suggest to us that MAM Ac treatment during gestation not only produces an acute lesion resulting in the destruction of many proliferating neuroblasts, but that many of the surviving neuroblasts may sustain a chronic lesion altering their subsequent development.
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  • 70
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    Acta neuropathologica 58 (1982), S. 307-310 
    ISSN: 1432-0533
    Keywords: Hirano body ; Hepatic encephalopathy ; Oligodendroglia ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Inclusions, essentially identical to Hirano bodies, were observed in the substantia nigra, dentate nuclei, and frontal lobes in three autopsy cases of hepatic encephalopathy. Similar inclusions were not observed in these areas in nine controls. The inclusions were mainly seen in the inner loops of the myelinated fibers, between the myelin lamellae, and among degenerated myelin sheaths. The same inclusions were rarely observed in postsynaptic terminals.
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  • 71
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    Acta neuropathologica 57 (1982), S. 151-157 
    ISSN: 1432-0533
    Keywords: Experimental ; Hematogenic ; Metastases ; Schwannoma ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study development, growth patterns and morphology of metastatic schwannomas in an animal model, adult Lewis rats were injected intravenously with tissue culture cells derived from a malignant schwannoma induced in a female LEW/mai rat by transplacental administration of ethylnitrosourea (LNU). Groups of animals received a single injection of 0.1×105; 0.5×105; 1.0×105; 5.0×105; 10×105 or 100×105 cells via the femoral vein. The injections resulted in the development of metastatic tumors, primarily involving the lung in all animals. Lung metastases were observed in the form of microscopic and macroscopic peripheral subpleural tumors, central peribronchial and perivascular tumors, parenchymal tumors, diffuse intraalveolar infiltrates and intravascular tumor emboli which were growing. Animals receiving high dosages had a greater variety of forms of the metastatic growth in the lungs than those given low dosages. The animals which received the highest dose had the greatest degree of total lung tumor burden. In 36 of the 60 animals injected, metastatic tumors also developed in the pericardium. Thirteen animals developed metastatic tumors in the kidney, heart, ovary, adrenal, intestine or skeletal muscles. As the cell dosages were increased, more organs became involved, but no tumors developed in the brain.
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  • 72
    ISSN: 1432-0533
    Keywords: Decompression sickness ; Hypertonic solutions ; Blood-brain barrier ; Blood-spinal cord barrier ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The permeability of microvasculature in the cerebral cortex, neostriatum, and spinal cord to i. v. injected horseradish peroxidase (HRP) has been investigated in rats following experimental compression to 6.1 bars (abs.) air for 90 min, and subsequent decompression to the ambient pressure in 1 min. For comparison, 1 ml of 2.0 M urea was injected into the right common carotid artery of rats during 15 s. After exposure to compression-decompression, under the light microscope focal leaky areas were found in all the regions examined. The leakage was most prominent in the grey matter of the spinal cord, and the cerebral cortex. In decompressed rats, arterioles were most often the site of peroxidase extravasation, whereas extravasation of HRP was less frequently displayed by capillaries and venules. In urea-treated rats, capillaries and venules frequently displayed extravasation of HRP as well. Parenchymal cells accumulated the trace adjacent to the leaky areas. Under the electron microscope, the extravasation of HRP was associated with peroxidase-containing pleomorphic vesicular structures in the endothelium, both in decompressed and urea-injected rats. Moreover, in contrast to decompressed rats, the junctions between endothelial cells were penetrated by the trace in urea-treated rats. Accordingly, the results indicate that during decompression sickness the pathway for the extravasation of proteins is through vesicular transfer, whereas the injection of hyperosmolar urea induces extravasation, both through vesicular transfer and junctions between the endothelial cells.
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  • 73
    ISSN: 1432-0533
    Keywords: Skeletal muscle ; Paraplegia ; Complete spinal cord lesion ; Histopatology ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Biopsies of the rectus femoris muscle of 22 paraplegic patients with complete acute spinal cord transection due to trauma were taken for enzyme-histochemical and electron-microscopic studies in successive stages starting from the occurrence of the accident (1–17 months). Ingravescent muscular atrophy was demonstrated with a progressive decrease in the fiber diameter and changes in the fiber type distribution with predominant type II atrophy in the first stage and type I atrophy in the later stage of the cord transection. Muscular “neurogenic” changes, such as angular dark atrophic fibers, targetoid fibers, and type predominance are frequently observed. Myopathic alterations are observed in a low percentage in the later stages of the lesion. The ultrastructural findings are characterized by myofibrillar alterations and by dilatation and proliferative phenomena of the sarcoplasmic reticulum and T-system. There are ingravescent accumulation of lipid, interstitial fibrosis and microcirculatory alterations. The possible mechanism of “central” muscle atrophy is reviewed and discussed with reference to the morphological findings.
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  • 74
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    Anatomy and embryology 164 (1982), S. 9-18 
    ISSN: 1432-0568
    Keywords: Ovariectomy ; Growth ; Bone ; Rat ; Tetracycline
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of ovariectomy on longitudinal bone growth was studied in growing rats. The operation was performed at ages 20, 40, and 60 days. Sham operations were made at age 40 days. At different postoperative intervals, the growth rate was determined with the tetracycline technique, and the width of the growth plate was registered. After a slight initial retardation, the growth rate after ovariectomy was significantly greater than in normal rats during a 40–60 day period. During the same period, the growth plate was wider. The increase in growth rate was greater and more rapid if ovariectomy was performed in older animals. The results indicate that ovariectomy increases longitudinal bone growth and that longitudinal bone growth and skeletal maturation depend less on ovarial function in young animals than that in more mature animals.
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  • 75
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    Anatomy and embryology 164 (1982), S. 19-41 
    ISSN: 1432-0568
    Keywords: Human kidney ; Nephron development ; Distal segments ; Electron microscopy ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ultrastructural development of the human distal nephron was studied in fetuses 14–18 weeks of gestational age. The three-dimensional course of the nephrons was traced in serial semi-thin sections. Single semi-thin sections containing defined distal nephron segments were then reembedded, thin-sectioned and analyzed by electron microscopy. In stage I (renal vesicle) and stage II (S-shaped body) epithelial cells were essentially similar in ultrastructure. In stage III there were only minor variations in cell ultrastructure between distal nephron segments, but distinct differences were observed between proximal and distal tubule cells, the former being the most differentiated. The segments which are present in nephrons of adult kidneys could be identified in stage IV and some ultrastructural differences recognized between the cells. However, the amplification of the baso-lateral membrane, which is prominent in iontransporting mature distal segments, was almost absent and the baso-lateral membrane area per unit tubule length was similar in all distal segments. Intercalated cells were present towards the end of the distal convoluted and in the connecting tubule in stage IV but the ampulla of the collecting tubule was composed of cells with a uniform ultrastructure. Cell ultrastructure varied again to some extent in the collecting tubule. The present observations demonstrate that distal nephron segments in the human kidney are structurally undifferentiated in the early fetal development and suggest that they only to a limited extent are capable of modifying the composition of the tubular fluid.
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  • 76
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    Anatomy and embryology 165 (1982), S. 63-70 
    ISSN: 1432-0568
    Keywords: Pancreatic islet ; Cytogenesis ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Chronological development of immunoreactive, pancreatic endocrine cells was immunohistochemically studied in rats. The first immunoreaction occurs for glucagon on day 11.5 and for insulin on day 12.5 of gestation, respectively, in the cells located within the cap-like or tubular pancreatic primordium derived from the gut wall. Immunoreactive somatostatin cells appear first at the periphery of primitive islets on day 15.5. On day 18.5, the cells of the primitive islets obtain their definitive arrangement and the islets are now separated from the tissue of the exocrine pancreas. Decapitation or encephalectomy performed on day 16.5 embryos fails to influence the ensuing further development of endocrine pancreas. This suggests that the hypothalamus or pituitary does not play an essential role in the histogenesis of the pancreatic islets.
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  • 77
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    Anatomy and embryology 165 (1982), S. 213-232 
    ISSN: 1432-0568
    Keywords: Callosal connections ; Neocortex ; Columnar organization ; Rat ; Degeneration techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary After complete callosotomy the distribution of degeneration products was re-investigated in adult albino rats. Three to seven days post operation, coronal, horizontal and “flattened” sections were impregnated according to the new methods of Gallyas et al. (1980) which stain degenerating axons and terminals, respectively. The regional distribution patterns of callosal terminals were directly visualized with dark field illumination at low magnification. With this technique the distribution pattern of axons and terminals could be compared between different cortical regions and individuals. Callosal terminals tend to accumulate in patches or bands along the borders of cortical regions and areas. The concentration of callosal terminals was especially high at the common corners of more than two cortical areas. The callosal system shows a rather constant distribution pattern which is composed of column shaped subunits. Considerable individual variations were recognized concerning the number, position, shape, density and contiguity of the columnar units either occupied by callosal connections or empty. Although the laminar distribution of callosal terminals shows some similarities in different areas of the cortex, there is no common laminar pattern characteristic either for the whole neocortex or for any cortical region. The comparison between consecutive sections stained either for degenerating fibers or degenerating axon terminals revealed that the callosal axons do not determine directly the arrangement and packing density of callosal synapses. Whatever determines the position and amount of callosal synapses this influence seems to be exerted via translation into the columnar organization.
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  • 78
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    Anatomy and embryology 165 (1982), S. 345-359 
    ISSN: 1432-0568
    Keywords: Lateral reticular nucleus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The synaptic relationships and the distribution of the afferent terminals of the spinal pathway to the lateral reticular nucleus (LRN) of the rat were examined following induced degeneration. After high cervical hemisections, the spino-LRN projection was first examined with the Fink-Heimer silver impregnation method. Degeneration was confined primarily to the ipsilateral LRN and all three divisions of the nucleus were involved. Maximum degeneration was observed in the caudal regions of the parvocellular division. The magnocellular division, except for the extreme dorsomedial area, showed substantial degeneration as well. The subtrigeminal division throughout its entire length contained only sparse degeneration. Electron microscopic examination following spinal cord lesions revealed both round and pleomorphic-vesicle terminals in various stages of electron dense degeneration. The majority of the degenerating terminals were of the round-vesicle variety. Both types of terminals contacting somata were also observed to degenerate but their number was small in comparison to those on dendritic profiles. Terminals in synaptic contact with two dendritic profiles were also observed to degenerate. Some of the large terminals belonging to synaptic configurations (glomeruli) underwent degeneration and were therefore of spinal origin as well.
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    Anatomy and embryology 164 (1982), S. 243-256 
    ISSN: 1432-0568
    Keywords: Lateral reticular nucleus ; Golgi ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The organization of the lateral reticular nucleus (LRN) of the rat was investigated by using the Golgi technique. Golgi-Cox preparations revealed neurons with shapes similar to those observed in Nissl-stained preparations. Fusiform cells possess rectilinear dendrites with secondary dendrites which are longer than the parent stem. The remaining cell types have short dendrites which branch for three or four generations and follow a tortuous course. These two types of neurons are similar to the isodendritic and allodendritic neurons which have been reported in the reticular formation. The neurons throughout the LRN form cell clusters. In Golgi preparations five to ten cells are seen in each cluster but counterstaining reveals that the clusters are made up of many more cells than the Golgi preparations suggest. Many cells lie in close apposition and the dendrites of the cells in each cluster intertwine to form dendritic plexuses. Dendritic input from both neighbouring and distant cell clusters also contributes to the plexus formations within each cell cluster. Under high magnification, the dendrites show irregularities in their contours, including warty excrescenses, bumps and an array of spines, some of which are pedunculated. The appendages are confined primarily to distal portions of the dendrites, with few spines observed on the somata and proximal dendrites. Varicosed dendrites are also in common occurrence throughout the nucleus.
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  • 80
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    Anatomy and embryology 164 (1982), S. 315-330 
    ISSN: 1432-0568
    Keywords: Kidney ; Loop of Henle ; Differentiation ; Growth and development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The epithelial differentiation of the loop of Henle was investigated in the kidneys of Wistar rats between embryonic day 15 and postnatal day 30. Three stages can be distinguished in the development of the loop of Henle: (1) the primitive loop, (2) the immature loop and (3) the mature loop. The primitive loop of Henle is composed of thick undifferentiated tubule epithelium and is divided into a strongly basophilic proximal tubule anlage that stains dark in the semithin section, and a weakly basophilic, light-staining distal tubule anlage. The two anlages are separated by a cytologically sharp boundary located in the descending limb just before the bend of the loop. The immature loop of Henle is present when differentiation of the tubule epithelium begins. The shorter initial portion of the proximal tubule anlage develops into proximal straight tubule epithelium with brush border, brush border enzymes and lysosomal enzymes, while the longer, more distal portion of the proximal tubule anlage develops into thin undifferentiated epithelium that is a transitory feature of the immature loop stage. The primitive epithelium of the distal tubule anlage develops into distal straight tubule epithelium. The cytologically sharp boundary of the thin undifferentiated epithelium and distal tubule epithelium is located just before the bend of the loop. The loop of Henle matures as the thin undifferentiated epithelium in the medullary ray and outer stripe of the outer medulla becomes transformed into proximal straight tubule epithelium. At the point where this descending differentiation ends, the borderline of the inner and outer stripe of the outer medulla arises. The thin undifferentiated epithelium in the inner stripe and the inner medulla differentiates into the thin epithelium of the descending limb of Henle's loop. In the bend and ascending limb of long loops, the thick distal tubule epithelium is trans-formed by an ascending autophagous process into the thin epithelium of the ascending limb of Henle. The termination of this process marks the borderline between the inner and outer medulla. The thin descending and thin ascending limb of Henle arise from 2 different anlages; between them lies the histogenetic boundary of the proximal and distal renal tubule.
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  • 81
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    Anatomy and embryology 165 (1982), S. 19-37 
    ISSN: 1432-0568
    Keywords: Auditory system ; Inferior colliculus ; Cell migration ; Neuronal differentiation ; Radial glial fibers ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The early histogenesis of the inferior colliculus from embryonic day 11 to 18 (E11 to E18) has been studied in the rat by analysis of Golgi impregnated material and plastic sections. This analysis has shown that the pseudo-stratified columnar neuroepithelium observed at E11 is followed by the appearance at E12 of three zones: marginal, intermediate and ventricular. Signs of cell differentiation are first observed in the intermediate zone. Secondary rearrangements occur within this zone, and by E16 a thin cortical plate (the cortex of the inferior colliculus) develops at the junction of the intermediate and marginal zones giving rise to the external and pericentral nuclei of this structure, which has a cortical organization in adults. The remainder of the intermediate zone (the nucleus of the inferior colliculus), invaded by axons, expands dramatically by E16–E17 and gives rise to the central and dorso-medial nuclei of the inferior colliculus which have a nuclear organization in adults. The morphogenetic events which take place in these two regions differ and can be identified by the study of cell migration and differentiation. In the nucleus of the inferior colliculus, neuronal migration begins with detachment of the ventricularly directed process, or trailing process, of the primitive epithelial cell from the ventricular surface. This is followed by the ascent of the cell nucleus through the pially directed, or leading, process by a mechanism identical to the perikaryal translocation already described in other regions of the nervous system. This mechanism of cell migration is characteristic of a first type of migratory young neuron (type I). Axons initiate from the leading process of these cells during migration and dendrites grow out in various directions giving these cells a bipolar or a multipolar appearance. Dendritic differentiation occurs first in the outermost cells of the nucleus and proceeds inwards. In the cortex of the inferior colliculus, neuronal migration also begins with detachment of the ventricular process, which occurs by E12, immediately followed by the detachment and retraction of the apical or leading process. Within the intermediate zone, migratory cells become rounded and sprout numerous processes. One of these processes is tipped by a growth cone and displays all the characteristics of an axon. It is directed tangentially in the intermediate layer. Dendritic growth and differentiation starts when the cells reach their final position in the cortical plate, and proceeds from the innermost cells outward. Due to the inadequacy of our methods for identifying radial glial fibers, the mechanism of migration of this type of cell (type II) remains unclear. Our results confirm that the inferior colliculus of the rat is organized as a central nuclear mass surrounded by a thin cortex. As previously observed in other regions of the nervous system, the modes of cell migration and differentiation in the cortical and non-cortical structures of the inferior colliculus appear different.
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  • 82
    ISSN: 1432-0568
    Keywords: Inferior vena cava ; Autonomic nervous system ; Adrenergic nerves ; Cholinergic nerves ; Mouse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The innervation pattern of rat and mouse inferior vena cava was studied using catecholamine fluorescence and cholinesterase histochemical methods. Adrenergic nerve fibers innervate only abdominal protions of the inferior vena cava, while cholinergic nerves are chiefly distributed to the thoracic inferior vena cava and show a gradual decrease in the abdomen. Chemical sympathectomy performed with the neurotoxin 6-hydroxydopamine does not alter the pattern of cholinergic innervation of the inferior vena cava, suggesting the parasympathetic nature of cholinergic nerves.
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    Anatomy and embryology 165 (1982), S. 329-344 
    ISSN: 1432-0568
    Keywords: Lateral reticular nucleus ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A systematic study of the normal synaptic patterns within the lateral reticular nucleus (LRN) of the rat revealed various synaptic relationships. Two types of axon terminals were identified according to the morphology of the synaptic vesicles contained within them. Axon terminals with round vesicles established asymmetrical synaptic contacts with the somata and all areas of the dendritic trees including somatic and dendritic appendages. Pleomorphic-vesicle terminals established symmetrical synaptic contacts on somata and their appendages and on all sizes of dendrites and their appendages. Both round and pleomorphicvesicle terminals were infrequently seen to synapse upon the somata and proximal dendrites. The round-vesicle terminals outnumbered the pleomorphic-vesicle terminals on the dendritic trees. Terminals of the en passant type were also common throughout the LRN. Both round and pleomorphic-vesicle terminals were observed simultaneously contacting the soma and one or more dendritic profiles, or two different dendritic profiles. Synaptic configurations (glomeruli) were also observed in all three divisions of the nucleus. They consisted of a large, central, round-vesicle terminal contacting a number of small-calibre dendritic processes. This arrangement was surrounded by one or more sheets of glial lamellae. Puncta adherentia were observed on the apposed membranes of adjacent cells, adjacent dendrites and adjacent axon terminals.
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  • 84
    ISSN: 1432-0584
    Keywords: Multiple myeloma ; Immunoglobulin ; Electron microscopy ; Fluorescent antibody technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Using our electron microscopic method for polysome analysis and an immunofluorescent technique we studied Ig production and secretion by tumor cells in seven BJP myeloma patients and seven “nonsecretory” myeloma patients. In BJP myeloma Ig production and secretion is of three types: Type 1, only L-chains are synthesized and secreted; Type 2, the myeloma cells show fluorescence for H-chains, but upon polysome analysis there is no peak at polysomes corresponding to H-chain production; Type 3, the myeloma cells show fluorescence for H-chains, and polysome analysis shows two peaks corresponding to L- and H-chain production. Polysome analysis of “nonsecretory” myelomas show the presence of only very few membrane-bound polysomes and their distribution curves are entirely different from those of “ordinary” myeloma. Furthermore, the distribution patterns vary among seven cases. Results obtained by polysome analysis and immunofluorescent technique suggest that the “nonsecretory” myeloma could be divided into several subtypes.
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    Acta neuropathologica 56 (1982), S. 250-254 
    ISSN: 1432-0533
    Keywords: Skeletal muscle ; Chronic alcoholism ; Tubular aggregates ; Histochemistry ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The presence of tubular aggregates (TA) in type II muscle fibers in two of 20 alcoholic patients with chronic liver disease, and with no apparent neuromuscular disorder, is reported. The localization, histochemical reactions, and ultrastructural features of the TA are similar to those previously described in other conditions. In one of the two cases TA were demonstrated by E/M observations only and not by histochemistry. No correlations were found between the biochemical changes and the presence of tubular aggregates. We believe that TA are long-standing structures since the muscle biopsies were performed 12 and 13 days after the ingestion of alcohol had been discontinued. They may represent a non-specific response of the sarcoplasmic reticulum to compensate for the deficient calcium uptake reported in alcoholic patients.
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    Acta neuropathologica 58 (1982), S. 177-182 
    ISSN: 1432-0533
    Keywords: Cerebral vessels ; Telencephalon ; Looptail mutant mouse ; Pathogenesis ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cerebral capillaries in the telencephalon of normal (+/+;Lp/+)_and abnormal (Lp/Lp) loop-tail mutant mice were studied chronologically by means of electron microscopy at stages ranging from 15 through 18 days of gestation. In the abnormal tissue, neural rosettes were common, and cellular material and red blood cells were often contained within the lumen of the rosettes. The endothelial cells of telencephalic blood vessels in the abnormal brains showed a persistence of cellular projections, subluminal vacuoles, and swollen mitochondria beyond the stage when these features ordinarily disappear in normal embryonic cerebral vessels. The endothelial cells in the abnormal brains also failed to become fully invested with pericytes, and red blood cells gradually infiltrated the neural tissue, particularly in subependymal regions, at 16–18 days of gestation.
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    Acta neuropathologica 57 (1982), S. 306-308 
    ISSN: 1432-0533
    Keywords: Blood vessel ; Brain ; Development ; Neuro-active ; Drugs ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The morphological effects of two chemically different neuroactive drugs (chlorpromazine and phenobarbital) on vasculogenesis in rat cerebellum were examined to determine the presence of vascular alterations. Therapeutic dosages of both drugs were chronically administered to separate groups of maternal rats beginning on days 10, 13, 15, 18, and 21. In chlorpromazine-treated animals the specific length of blood vessels was most severely reduced in the Purkinje cell layer. Animals treated with phenobarbital demonstrated an initial reduction in specific length in the Purkinje cell layer but returned to control values by day 21 postnatal (p.n.). Blood vessels in the molecular and granular layers showed little change. The observed changes have been discussed in relation to possible mechanisms and and their relationship to neurogenesis.
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    Archives of dermatological research 274 (1982), S. 373-375 
    ISSN: 1432-069X
    Keywords: Merkel cell ; PUVA ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
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    Development genes and evolution 191 (1982), S. 205-207 
    ISSN: 1432-041X
    Keywords: Chitin inhibition ; Nikkomycin ; Cuticle ; Electron microscopy ; Epilachna varivestis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The nucleoside antibiotic nikkomycin has proved to be an effective inhibitor of chitin synthesis in the Mexican bean beetleEpilachna varivestis. Ultrastructural investigations show defects in the procuticular area after nikkomycin application which suggest the complete absence of chitin. A cuticle like this is inflexible and too brittle to satisfy its normal function as an exoskeleton. The individuals are not able to free themselves from the exuvia and finally die. Therefore nikkomycin seems to be a potential insecticide with high specifity.
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  • 90
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    Calcified tissue international 34 (1982), S. 211-213 
    ISSN: 1432-0827
    Keywords: Rat ; incisor ; ameloblasts ; enamel ; 45Ca autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Rats were injected with45Ca and horseradish peroxidase to determine the patterns of45Ca incorporation into incisor enamel and the morphological types of the overlying maturation ameloblasts.45Ca autoradiography showed no differences in the patterns of incorporation into enamel between routinely embedded and freeze-dried specimens. Enamel overlaid by ruffle-ended ameloblasts was much more heavily labeled while that overlaid by smooth-ended ameloblasts showed only moderate labeling. The observations lend further support to the hypothesis that the ruffle-ended cells are very active in mineralizing enamel and that the smooth-ended cells are in a passive, restorative phase.
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  • 91
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    Calcified tissue international 34 (1982), S. 376-381 
    ISSN: 1432-0827
    Keywords: Matrix vesicles ; Bone ; Actin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Preliminary indications of the occurrence of actin and myosin in crude matrix vesicle preparations have been reported previously. In the present study extracellular matrix vesicles from rat alveolar bone were isolated. They were further purified by a sucrose density gradient. SDS-polyacrylamide gel electrophoresis of the purified vesicles revealed the presence of a polypeptide with a molecular weight of 43 K daltons and with electrophoretic mobility identical to that of blood platelet actin. The limited proteolysis of both 43 K dalton vesicular polypeptide and actin byStaphylococcus aureus-V8-protease revealed three fragments with identical electrophoretic mobility. In addition, the vesicular preparations inhibited the activity of DNase I, a property typical of actin monomers. Filamentous material extracted from matrix vesicles showed ultrastructural features of F-actin. Reaction of this material with heavy meromyosin resulted in arrowhead formation, which is characteristic of acto-heavy meromyosin. The occurrence of actin in extracellular matrix vesicles may account for their budding from the osteoblastic plasma membrane, their possible motility in the matrix, and maintenance of the spherical shape.
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  • 92
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    International archives of occupational and environmental health 49 (1982), S. 305-314 
    ISSN: 1432-1246
    Keywords: Polycyclic aromatic hydrocarbon ; Liver ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Female NMRI mice aged 9–12 weeks were each given a single subcutaneous injection of 0.5 ml of a suspension containing either the total extracts or the polycyclic aromatic hydrocarbon (PAH) fraction of airborne particles. Both the total extracts and PAH fractions contain 3 Vg benzopyrene. After about 15 months the livers were removed from the animals, which had by that time developed tumors at the injection site, and were subjected to ectronmicroscopical study. The essential alterations were observed in the nucleoli and the cell nuclei, which had greatly proliferated and exhibited irregular nuclear membranes. Advanced fibrosis was observed in central liver specimens of all groups. Marked alterations were also observed in the mitochondria and the mitochondria) cristae as well as in the bile canaliculi. Intracytoplasmic glycogen usually occurred densely clustered along the periphery of the cell. It may be concluded from the observations that both the total extract of atmospheric suspended particulate matter and the PAH fraction cause hematogenic damage to the liver following subcutaneous injection, a finding which cannot be interpreted as metastatic carcinoma.
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  • 93
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    Journal of cancer research and clinical oncology 104 (1982), S. 171-180 
    ISSN: 1432-1335
    Keywords: Ewing's sarcoma ; Type IV collagen ; Factor-VIII-associated protein ; Endothelial differentiation ; Electron microscopy ; Immunofluorescence microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Six cases of Ewing's sarcoma were investigated by electron and immunofluorescence microscopy. A layer of basement membrane-like deposits was found between typical principal and secondary tumor cells. To clarify the nature of these ultrastructural deposits, antibodies against collagen type IV were applied to frozen sections of corresponding tumor tissue. This reaction revealed type IV collagen as a regular component of basement membranes in nonneoplastic tumor capillaries, but it was equally able to localize collagen type IV between single tumor cells in capillary-free areas. With the same method, factor-VIII-associated protein, predominantly found in endothelial cells, could be demonstrated in some tumor cells. These results demonstrate that, in addition to anaplastic cells, some tumor cells are found in Ewing's sarcoma that share certain differentiating features with the endothelial cell.
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  • 94
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    Experimental brain research 46 (1982), S. 315-323 
    ISSN: 1432-1106
    Keywords: Rat ; Dentate granule cells ; Volumetric analysis ; Adult ; Neurogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The total number of granule cells in the dentate gyrus was estimated in 17 male rats, four each aged 30, 120, and 200 days, and five aged 365 days. There is a substantial 35–43% linear increase between 1 month and 1 year. Two parameters of the granular layer are involved in the numerical change. First, total granular layer volume grows linearly with age. Second, average volume of a single granule cell nucleus in the ventral dentate gyrus decreases with age. Older rats tend to have a larger granular layer filled with more and smaller cells. In another group of 21 male rats, 3H-thymidine injections were given on four consecutive days during juvenile (30–33, n = 6) and adult life (60–63, n = 5; 120–123, n = 6; 180–183, n = 4). All animals survived to 200 days of age. The proportion of labeled mature granule cells and labeled presumptive granule cell precursors were determined in anatomically-matched slices. With older ages at injection, there is a decline in labeled mature granule cells and a concurrent increase in labeled precursors. These data are compatible with the constant level of granule cell increase determined volumetrically. Most of the late granule cells originate nearly simultaneously along the base of the main bulk of the granular layer; very few are found in the dorsal tip (septal extreme) and ventral tip (temporal extreme). This study is the first demonstration of a net numerical gain in a neuronal population during adulthood in the mammalian brain. Since the granule cells play a pivotal role in hippocampal function, these data suggest that their influence grows with age.
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    Experimental brain research 48 (1982), S. 420-428 
    ISSN: 1432-1106
    Keywords: ADH-neurone ; Amygdala ; Rat ; Supraoptic nucleus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of amygdala stimulation on the discharge activity of antidromically identified supraoptic neurosecretory neurones were studied in male rats anaesthetized with urethane. Stimulation of the medial and the basal amygdala produced excitation or inhibition of discharge activity both in phasically firing (“phasic”) and in continuously firing (”continuous”) neurones. More “phasic” neurones were excited than were inhibited after medial amygdala stimulation. On the other hand, fewer “continuous” neurones were excited by stimulation of the either amygdala area than were inhibited. This difference of responsiveness between “phasic” and “continuous” neurones is statistically significant. Synaptic inputs to supraoptic neurosecretory neurones after amygdala stimulation were also observed in rats with a lesion of the stria terminalis. Supraoptic nucleus stimulation activated antidromically 14 of the 336 amygdala neurones tested. Since “phasic” neurones have been identified as ADH-secreting neurones, it is concluded that ADH-secreting neurones in the rat supraoptic nucleus receive predominantly excitatory synaptic inputs from the medial amygdala and these amygdalar synaptic inputs are mediated by pathways which are at least in part monosynaptic and are not included in the stria terminalis.
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  • 96
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    Experimental brain research 46 (1982), S. 383-392 
    ISSN: 1432-1106
    Keywords: Electrophysiology ; Hypothalamus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The responses of 700 single neurons in the hypothalamus to electrical stimulation of the preoptic area, limbic structures, and midbrain were studied to determine the location of neurons with multiple inputs and to identify by antidromic activation the projection areas of those neurons. Converging excitatory inputs, observed in 134 responsive hypothalamic neurons, were principally derived from the preoptic, limbic, and midbrain areas. Inputs from separate nuclei of the amygdala were noted in the response of individual hypothalamic neurons. Two classes of short latency transsynaptic responses to amygdala stimulation were defined, indicating either separate pathways from the amygdala to the medial hypothalamus or two types of fibers conducting at different velocities. Stimulation of single or multiple sites in the preoptic and limbic areas, as well as in the arcuate nucleus and medial forebrain bundle produced inhibition of hypothalamic neuronal activity. Most antidromically identified medial hypothalamic neurons projected to the preoptic area, median eminence (tuberoinfundibular neurons), or midbrain. Evidence is presented for collateral projections of tuberoinfundibular neurons to the preoptic area and reticular formation. Medial hypothalamic neurons received inputs from the preoptic area, lateral septal nucleus, amygdala, ventral hippocampus (subiculum), and fornix. These findings illustrate a pattern of reciprocal connections between the medial hypothalamus and limbic and midbrain structures. It was concluded that the hypothalamus contains a type of neuron that is equipped to perform complex integrations and to coordinate directly the behavior of neurons in a diversity of anatomical regions.
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    Experimental brain research 47 (1982), S. 437-445 
    ISSN: 1432-1106
    Keywords: Rat ; Tectal transplants ; Host afferents ; Functional innervations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Fetal tectal tissue was transplanted adjacent to the superior colliculus of neonatal rats. In mature recipient animals, ultrastructural studies provided evidence of host cortical synapses on cells within the transplants. To determine whether these synapses were functionally effective in driving transplant cells, tungsten in glass microelectrodes were used to record from single units in the transplants and the host cerebral cortex was electrically stimulated. Of the 214 tested units which were shown histologically to be within the transplants, 25 (11.7%) were orthodromically excited from host cortex at latencies of 15 ms or less (mean 7.3 ms). A further four transplant units were activated at relatively long latencies (40–300 ms). The presence of a functional host retinal input was also tested by electrically stimulating the host optic nerves. No transplant units were activated from these sites, apparently because very few electrode penetrations passed through the localized zones of optic axon distribution. The possible functional interrelationships between transplant and host are discussed.
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    Experimental brain research 45 (1982), S. 84-88 
    ISSN: 1432-1106
    Keywords: Rat ; vLGN ; Geniculo-tectal relay cells ; HRP ; Golgi-method
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In the rat's ventral lateral geniculate nucleus (vLGN), geniculo-tectal relay neurons (GTR-neurons) could be identified by the retrograde transport of horseradish peroxidase (HRP) after injection in the superior colliculus (SC). GTR-neurons correspond to class III cells described by Brauer and Schober (1973) in Golgi preparations of the rat's vLGN. The distribution of GTR-neurons is restricted to the lateral subnucleus of vLGN. According to Swanson et al. (1974), the axons of these cells terminate in lower Stratum griseum superficiale and in Stratum opticum, Stratum griseum intermedium and Stratum album intermedium of SC. The GTR-neurons are characterized by very thick and long proximal dendritic segments which have a smooth surface. Dendrites branch preponderantly in their distal regions and only in this part form many multiform protrusions. There is some evidence that retinal axons terminate on these dendritic surface structures. The supposed differences in the afferent patterns between GTR-neurons in the vLGN and geniculo-cortical relay neurons in the dorsal lateral geniculate nucleus are discussed.
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    Experimental brain research 47 (1982), S. 286-294 
    ISSN: 1432-1106
    Keywords: Semicircular canal ; Vestibular ; Primary afferent neuron ; Rat ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In rats and guinea pigs, primary afferent neurons from the horizontal semicircular canal were divided into two categories, regular and irregular, on the basis of the regularity of their resting activity. Regular neurons tend to have higher average resting rates than irregular neurons and in response to a constant angular acceleration stimulus of 16.7 deg/s2 regular neurons tended to have lower sensitivity and longer time constants than irregular cells. Some irregular neurons are more sensitive to incremental accelerations than to decremental accelerations of the same magnitude, whereas regular neurons tend to show symmetrical sensitivity. In response to sinusoidal angular acceleration stimuli (fixed frequencies) in the range 0.01–1.5 Hz, cells which fired regularly at rest tended to have smaller gain and longer phase lag re acceleration at most frequencies than irregular cells. Transfer functions were obtained for averaged data for regular and irregular neurons separately in both species. In both species there is evidence of systematic variation between neurons within each category, and this systematic variation is obscured by averaging across neurons.
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    Experimental brain research 47 (1982), S. 295-300 
    ISSN: 1432-1106
    Keywords: Semicircular canal ; Vestibular ; Primary afferent neuron ; Development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary At birth primary horizontal semicircular canal afferent neurons in the albino Wistar rat have slow, irregular spontaneous activity and insensitive, sluggish, variable responses to sinusoidal angular acceleration stimuli. There are rapid changes in the gross morphology of the rat semicircular canal in the first 4–5 days after birth, and during this time there is a rapid increase in neural gain re acceleration. Irregular neurons in rats about 6 days old have gains in the same range as irregular neurons in adult rats. However, after the gross morphological growth is complete, there continues to be a decrease in phase lag re acceleration. The causes of this developmental change in phase are unknown. It could be produced by changes in the receptor-afferent-efferent complex or by changes in the cupula or cupula-hair-cell attachment. These results with sinusoidal accelerations confirm the developmental increase in sensitivity and decrease in time constant found with constant angular accelerations (Curthoys 1979b).
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