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  • Ultrastructure  (5)
  • Keratinization  (3)
  • Physics  (3)
  • Purkinje cells  (3)
  • 1
    ISSN: 1432-1106
    Keywords: Purkinje cells ; Deiters neurones ; Inhibitory synapses ; GABA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1.Various drugs were applied intravenously or into the fourth ventricle and their effects upon the inhibition exerted by Purkinje cell axons were appraised by both extra- and intracellular recording from Deiters neurones. Strychnine, picrotoxin, pentamethylenetetrazol, β-methyl-β-ethylglutarimide, noradrenaline, dopamine, dibenamine and nethalide did not affect this inhibition. 2.γ-aminobutyric acid (GABA) and inhibitors of GABA transaminase were applied iontophoretically into the vicinity of Deiters neurones through an outer barrel of coaxial electrodes, the effects being observed either intra- or extracellularly through an inner barrel. 3. GABA depressed both inhibitory and excitatory postsynaptic potentials and often blocked the spike potentials, while it increased the membrane conductance. 4. GABA also produced a membrane hyperpolarization of 3–8 mV. Concomitantly both the spike potential and after-depolarization increased in amplitude and the after-hyperpolarization decreased. 5. In a few cases hydroxylamine but not amino-oxyacetic acid potentiated the inhibition, there being an increase in the inhibitory postsynaptic potentials thereby induced. 6. These effects were considered in connection with the possibility that GABA acts as a natural transmitter.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-069X
    Keywords: Inflammatory linear epidermal naevus ; Keratinization ; DACM ; Involucrin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Skin lesions of three patients with inflammatory linear verrucose epidermal naevus (ILVEN) were examined. Histologically, orthokeratosis and parakeratosis were alternately seen in the acanthotic epidermis. By N-(7-dimethylamino-4-methyl-3-coumarinyl)maleimide staining, the horny cells in the parakeratotic epidermis showed a cytoplasmic SH pattern and a weak membranous SS pattern. The orthokeratotic epidermis revealed an increased involucrin expression, whereas the parakeratotic epidermis showed almost no involucrin expression. Ultrastructurally, in the parakeratotic epidermis, the living keratinocytes had prominent Golgi apparatuses and vesicles in the cytoplasm. In the intercellular spaces in the upper spinous layer through to the lower horny layer, an electron dense, homogeneous substance was deposited. The cytoplasm of the horny cells was filled with keratin filaments and contained remnants of nucleus and cytoplasmic membrane structures, and some lipid droplets. The marginal band formation was incomplete. Most of these ultrastructural abnormalities were not found in the orthokeratotic epidermis. There are both similarities and differences in histopathogenesis of the parakeratotic epidermis between ILVEN and psoriasis. A unique finding was the lack of involucrin expression in the ILVEN parakeratotic epidermis.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 282 (1990), S. 434-441 
    ISSN: 1432-069X
    Keywords: Hair cycle ; Human hair follicle ; Connective tissue sheath ; Hyaline membrane ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Ultrastructural changes of the connective tissue sheath (CTS), including the hyaline membrane, of human hair follicles during the hair cycle, were studied in normal scalp skin specimens. In early anagen, the CTS was composed of a thin basal lamina and surrounding collagen tissue. The collagen tissue gradually thickened during the development of the hair and hair follicle. In mature anagen hair follicles, the collagen tissue was separated into three layers. The inner collagen layer, just outside the basal lamina, was thin and composed of collagen fibres running longitudinally parallel to the hair axis. The middle collagen layer was very thick with its collagen fibres running transversely against the hair axis and surrounding the inner hair tissue. Many fibroblasts were present among the collagen fibres in the middle layer, whereas the inner layer contained almost none. In the outer collagen layer, collagen fibres ran in various directions parallel to the outer surface of the outer root sheath cells. In late anagen, the basal lamina became very thick. In catagen, the basal lamine and the inner collagen layer became corrugated and showed oedematous change and degeneration. Surrounding fibroblasts showed active production of new collagen fibres, which seemed to fill the spaces left by the retraction of the hair follicle and hyaline membrane. These ultrastructural changes of the CTS show that there may be dynamic metabolic changes of the connective tissue around human hair follicles during the hair cycle.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 279 (1986), S. 112-119 
    ISSN: 1432-069X
    Keywords: Innermost cell layer ; Outer root sheath ; Anagen hair follicle ; Keratinization ; Light and electron microscopes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate cell differentiation in the outer root sheath (ORS) of the human anagen hair follicle, scalp skin specimens from individuals with normal hair were examined using light and electron microscopes. In the bulbar portion, the ORS was composed of two cell layers. The cells in the outer layer gradually increased in number upwards and finally underwent so-called trichilemmal keratinization, which proceeded toward the hair canal. On the other hand, the inner cells in the bulb formed a single cell layer along the outside of Henle's layer during cell differentiation; this unique layer was referred to as the innermost cell (IMC) layer of the ORS. With the use of hematoxylin and eosin stain, at the suprabulbar portion, where Henle's cells were keratinizing, an eosinophilic substance was deposited in the inner (Henle's) side of the IMC cytoplasm. The IMCs gradually became entirely eosinophilic and often produced keratohyaline granules. Ultrastructurally, the IMCs of the ORS showed an oblong shape forming a regularly arranged single-cell layer along the keratinizing Henle's layer and accumulated tonofilaments in the cytoplasm. They produced a few small electron-dense keratohyaline granules and were keratinized at the level at which Henle's layer still preserved its cell structure. From these findings, it is suggested that there are two types of keratinization of the ORS: trichilemmal keratinization and IMC keratinization.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 280 (1988), S. 308-318 
    ISSN: 1432-069X
    Keywords: Pili annulati ; Ultrastructure ; DACM staining ; Hair cortex ; Protein metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Plucked scalp hairs and hair roots of pili annulati were examined to understand their pathogenesis. Stereoscopic examinations of hairs in transmitted light and/or reflected light and light microscopic surveys of the cross-sections of hairs confirmed that the cortical empty spaces appeared to be responsible to the unique dotted shiny appearance of the hairs seen by the unaided eyes under a refracted light. By transmission electron microscope, small vacuoles and dense bodies were observed in the cytoplasm of the differentiating cortical cells; subsequently, with increasing number of tonofilaments, an uneven distribution of free ribosomes occurred and abnormal spaces containing fine granular substances were formed in the cytoplasm of the cortical cells. Occasionally, extremely large cortical trichohyaline granules were found. In the keratinized hair, irregular empty spaces were present in the cortex of the abnormal hair segments. Histochemically, the keratinized cortex of the affected hairs always had more residual SH groups than the controls. Pili annulati may be a disorder of protein metabolism involving a partial dysfunction of cytoplasmic ribosomes, resulting in a lack of cortical keratin formation.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 284 (1992), S. 95-99 
    ISSN: 1432-069X
    Keywords: Chromoblastomycosis ; Host-fungus relationship ; Morphometry ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the histological distribution and the morphology of the fungi and the tissue reactions in chromoblastomycosis, especially in the process of trans-epidermal elimination, cutaneous lesions of two patients with this disease were studied morphometrically and ultrastructurally. In the dermis, most of the fungal elements appeared as sclerotic cells and their cell wall showed an irregular, worm-eaten leaf-like appearance; they seemed to be continuously attacked by polymorphonuclear neutrophils. The epidermis eliminated 10–20% of all the organisms in the skin lesions, and the hypha-forming activity tended to be higher in the epidermis than in the dermis. Ultrastructurally, basal keratinocytes facing the dermal abscess containing fungal elements frequently appeared as dark cells, suggesting an increased proliferation activity. Spinous keratinocytes facing intraepidermal microabscesses containing fungal elements showed an abnormal accumulation of tonofilaments and further early keratinization in the spinous cell layer. All of the morphological changes of the dermis and epidermis are regarded as defence reactions against the fungi existing in the skin lesions. There is a close relationship between tissue reactions and morphological changes of fungi in chromoblastomycosis.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archives of dermatological research 283 (1991), S. 141-148 
    ISSN: 1432-069X
    Keywords: Sjögren ; Larsson syndrome ; Ichthyosis ; Ultrastructure ; Lamellar body ; Keratinization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The ichthyosiform skin and the uninvolved skin of a 5-year-old Japanese female with Sjögren — Larsson syndrome were examined by light and electron microscopy to elucidate the keratinization disorder. Light microscopically, the epidermis of the ichthyosiform skin showed acanthosis, papillomatosis and hyperkeratosis. The horny cells had a basket-weave appearance. The granular cell layer was slightly thickened. Slight round cell infiltration and vascular dilatation were seen in the upper dermis. The uninvolved skin was histologically normal. Electron microscopically, in both ichthyosiform and uninolved skin, abnormal lamellar or membranous inclusions were present in the cytoplasm of horny cells of the epidermis. These inclusions appeared to be derived from some of the lamellar bodies and/or abnormal membranous structures found in the cytoplasm of spinous and granular cells. Mitochondria in the epidermal basal cells were more numerous in the ichthyosiform skin than in the uninvolved skin. These findings indicate that, whether the skin is involved or not, the epidermis of the patient with this disorder may always have a structural abnormality, which may be genetically determined. Local environmental factors may play a role in inducing the acanthosis and papillomatosis of the epidermis.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 10 (1970), S. 64-80 
    ISSN: 1432-1106
    Keywords: Intracerebellar nuclei ; Purkinje cells ; Inhibition ; Excitation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In anaesthetized cats, synaptic events in cerebellar nuclei neurones were investigated with intracellular microelectrode techniques. These cells were identified by their antidromic activation along their axons and/or by their location in histological sections. In the cells of lateral nucleus IPSPs were induced monosynaptically during stimulation of the overlying hemispheral cortex of the cerebellum. In the cells of nuclei interpositus and fastigii, similar IPSPs were produced from the paravermal and vermal cortices, respectively. The postulate that the Purkinje cells exert an inhibitory action upon their target neurones thus applies not only to Deiters neurones, as previously proposed, but also to cells in the cerebellar nuclei. Stimulation of the cerebellar afferents at the inferior olive, the pontine nucleus and the lateral reticular nucleus produced EPSPs in cerebellar nuclei cells with relatively brief latencies, probably through axon collaterals of these afferents. The EPSPs were followed by IPSPs and slow depolarizations of disinhibitory nature, which, as studied previously in Deiters neurones, might be caused respectively by activation and subsequent depression of Purkinje cells through the cerebellar intracortical mechanisms.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Experimental brain research 2 (1966), S. 330-349 
    ISSN: 1432-1106
    Keywords: Deiters neurones ; IPSP ; Monosynaptic ; Purkinje cells ; Inhibitory neurones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary During stimulation of the anterior lobe of the cerebellum, postsynaptic potentials were recorded intracellularly from ipsilateral Deiters neurones of the cat. In the majority of examined cells, the inhibitory postsynapic potentials were induced with short latency; 1.06 msec on the average from lobule III or IV. The latency was longer (1.23 msec) when the lobule V was stimulated, while it was shorter (0.86 msec) from the juxtafastigial region. It follows that the IPSP was produced via a monosynaptic pathway at a conduction velocity of 15 to 20 m/sec. Recording of the extracellular field potentials and focal stimulation within and around Deiters' nucleus further indicated that the inhibitory impulses propagated out of the cerebellum along a remarkable bundle of fibres which terminated within Deiters' nucleus. These results are all explicable by assuming that the cerebellar Purkinje cells are inhibitory in nature and so produce IPSPs monosynaptically in Deiters neurones via the long corticofugal fibres. Monosynaptic EPSPs were also detected in some Deiters neurones. They are considered to be mediated by the other pathways formed of axon collaterals of the cerebellar afferents.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Physics Edition 15 (1977), S. 605-616 
    ISSN: 0098-1273
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Molecular motions in a series of linear aliphatic polyesters [poly(ethylene adipate), poly(ethylene sebacate), poly(hexamethylene sebacate), and poly(decamethylene 1,16-hexadecanedicarboxylate)] were studied by dielectric measurements. Two loss maxima were observed for each polymer in the temperature range from -196 to about 60°C and in the frequency range from 110 to 105 Hz. The loss maxima of these polyesters, lying between -17 and -38°C at 110 Hz (β-relaxation), are due to the micro-Brownian motions of amorphous main chains. It was found that these β-relaxations are well described by the WLF equation. The loss maxima in the range from -88 to -109°C at 110 Hz (γ-relaxation), are attributed both to local mode motions of main chains in the amorphous region and to motions of the polar groups involved at the chain ends. For the β-relaxation, no simple relation between the methylene sequence length and the loss peak temperature was found. Furthermore, as the methylene sequence length decreased, the effective dipole moment of the polyesters increased gradually. These facts were explained in terms of interchain dipole attraction.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
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