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  • 1
    Electronic Resource
    Electronic Resource
    Sub-populations of melanocytes in pigmented basal cell carcinoma: a quantitative, ultrastructural investigation (2001)
    Copenhagen : Munksgaard International Publishers
    Journal of cutaneous pathology 28 (2001), S. 0 
    Details
    ISSN: 1600-0560
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Pigmentation is a characteristic clinical feature of basal cell carcinomas (BCCs) in Japanese patients. The pathogenesis of melanin pigment in pigmented BCCs is poorly understood.Methods: We have combined the techniques of morphometric analysis and electron microscopy to assess accurately the morphologic aspects of melanocytes that occurred in pigmented and non-pigmented areas of pigmented BCCs.Results: In the pigmented areas melanocytes were not only located along the basal membrane but also interspersed between tumor cells in the central parts of the tumor nest, and had large and numerous dendrites. Those in a supra-basal location displayed some degree of degeneration due to mitochondrion and melanosome swelling. In the non-pigmented areas melanocytes were only basally located, showed fewer dendrites, and frequently showed abortive melanosomes. However, melanocytes in these two different portions were in the active state of melanogenesis and proliferation. Ultrastructural cytomorphometric analysis also showed significant differences in most of the nuclear and cell parameters including nuclear and cell area, the nuclear/cell area ratio, cell perimeter and cell form factor between these two types of melanocytes. Particularly melanocytes in the pigmented areas were twice the cell size of the latter. In addition, the melanosomes remained almost completely in the apoptotic tumor cells, and the phagocytosis of the melanosome-containing apoptotic cells by the neighboring tumor cells appeared to be followed by the formation of the melanosome complexes.Conclusions: These findings suggest that different populations of melanocytes are probably present in pigmented BCCs, and repeated cycles of phagocytosis of melanosome-containing apoptotic cells may represent the predominant way of forming large melanosome complexes. The present morphological observation and quantitative analysis provide a morphological basis for further studies to interpret other pathologic changes in pigmented BCCs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1034/j.1600-0560.2001.280104.x
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  • 2
    Electronic Resource
    Electronic Resource
    Human group IIA secretory phospholipase A2 potentiates Ca2+ influx through L-type voltage-sensitive Ca2+ channels in cultured rat cortical neurons (2003)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 85 (2003), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Mammalian group IIA secretory phospholipase A2 (sPLA2-IIA) generates prostaglandin D2 (PGD2) and triggers apoptosis in cortical neurons. However, mechanisms of PGD2 generation and apoptosis have not yet been established. Therefore, we examined how second messengers are involved in the sPLA2-IIA-induced neuronal apoptosis in primary cultures of rat cortical neurons. sPLA2-IIA potentiated a marked influx of Ca2+ into neurons before apoptosis. A calcium chelator and a blocker of the L-type voltage-sensitive Ca2+ channel (L-VSCC) prevented neurons from sPLA2-IIA-induced neuronal cell death in a concentration-dependent manner. Furthermore, the L-VSCC blocker ameliorated sPLA2-IIA-induced morphologic alterations and apoptotic features such as condensed chromatin and fragmented DNA. Other blockers of VSCCs such as N type and P/Q types did not affect the neurotoxicity of sPLA2-IIA. Blockers of L-VSCC significantly suppressed sPLA2-IIA-enhanced Ca2+ influx into neurons. Moreover, reactive oxygen species (ROS) were generated prior to apoptosis. Radical scavengers reduced not only ROS generation, but also the sPLA2-IIA-induced Ca2+ influx and apoptosis. In conclusion, we demonstrated that sPLA2-IIA potentiates the influx of Ca2+ into neurons via L-VSCC. Furthermore, the present study suggested that eicosanoids and ROS generated during arachidonic acid oxidative metabolism are involved in sPLA2-IIA-induced apoptosis in cooperation with Ca2+.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2003.01712.x
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  • 3
    Electronic Resource
    Electronic Resource
    Group IB secretory phospholipase A2 induces neuronal cell death via apoptosis (2002)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 81 (2002), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Group IB secretory phospholipase A2 (sPLA2-IB) mediates cell proliferation, cell migration, hormone release and eicosanoid production via its receptor in peripheral tissues. In the CNS, high-affinity binding sites of sPLA2-IB have been documented. However, it remains obscure whether sPLA2-IB causes biologic or pathologic response in the CNS. To this end, we examined effects of sPLA2-IB on neuronal survival in primary cultures of rat cortical neurons. sPLA2-IB induced neuronal cell death in a concentration-dependent manner. This death was a delayed response requiring a latent time for 6 h; sPLA2-IB-induced neuronal cell death was accompanied with apoptotic blebbing, condensed chromatin, and fragmented DNA, exhibiting apoptotic features. Before cell death, sPLA2-IB liberated arachidonic acid (AA) and generated prostaglandin D2 (PGD2) from neurons. PGD2 and its metabolite, Δ12-PGJ2, exhibited neurotoxicity. Inhibitors of sPLA2 and cyclooxygenase-2 (COX-2) significantly suppressed not only AA release, but also PGD2 generation. These inhibitors significantly prevented neurons from sPLA2-IB-induced neuronal cell death. In conclusion, we demonstrate a novel biological response, apoptosis, of sPLA2-IB in the CNS. Furthermore, the present study suggests that PGD2 metabolites, especially Δ12-PGJ2, might mediate sPLA2-IB-induced apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2002.00800.x
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  • 4
    Electronic Resource
    Electronic Resource
    Amyloid β Protein Potentiates Ca2+ Influx Through L-Type Voltage-Sensitive Ca2+ Channels: A Possible Involvement of Free Radicals (1997)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 68 (1997), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Amyloid β protein (Aβ), the central constituent of senile plaques in Alzheimer's disease (AD) brain, is known to exert toxic effects on cultured neurons. The role of the voltage-sensitive Ca2+ channel (VSCC) in β(25–35) neurotoxicity was examined using rat cultured cortical and hippocampal neurons. When L-type VSCCs were blocked by application of nimodipine, β(25–35) neurotoxicity was attenuated, whereas application of ω-conotoxin GVIA (ω-CgTX-GVIA) or ω-agatoxin IVA (ω-Aga-IVA), the blocker for N- or P/Q-type VSCCs, had no effects. Whole-cell patch-clamp studies indicated that the Ca2+ current density of β(25–35)-treated neurons is about twofold higher than that of control neurons. Also, β(25–35) increased Ca2+ uptake, which was sensitive to nimodipine. The 2′,7′-dichlorofluorescin diacetate assay showed the ability of β(25–35) to produce reactive oxygen species. Nimodipine had no effect on the level of free radicals. In contrast, vitamin E, a radical scavenger, reduced the level of free radicals, neurotoxicity, and Ca2+ uptake. These results suggest that β(25–35) generates free radicals, which in turn, increase Ca2+ influx via the L-type VSCC, thereby inducing neurotoxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1997.68010265.x
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  • 5
    Electronic Resource
    Electronic Resource
    n-type amorphous (or microcrystalline) silicon/p-type crystalline silicon heterojunction electrodes for efficient and stable solar-to-chemical conversion (1988)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 1513-1518 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Silicon (Si) electrodes having a n-p heterojunction for hydrogen photoevolution were prepared by depositing n-type amorphous or microcrystalline Si layers on p-type single-crystal Si wafers by the plasma chemical-vapor-deposition method. Electrodes of this type, each coated with a thin platinum layer (about 1 nm) as a reaction catalyst, generated photocurrents much higher than those for Pt-coated n+ -p homojunction single-crystal Si electrodes, together with photovoltages nearly the same as those for the latter electrodes, clearly indicating the "window'' effect of the n-type amorphous or microcrystalline Si layer. A photoelectrochemical cell equipped with a Si electrode of the present type and a Pt-plate counterelectrode, separated with a cation exchange membrane, photodecomposed hydrogen iodide into hydrogen and iodine with a solar-to-chemical conversion efficiency of 10.8% (air mass 1, 100 mW/cm2 ), the highest of the efficiencies so far reported for the direct solar-to-chemical conversion without any externally applied voltage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.341826
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  • 6
    Electronic Resource
    Electronic Resource
    Effect of microscopic discontinuity of metal overlayers on the photovoltages in metal-coated semiconductor-liquid junction photoelectrochemical cells for efficient solar energy conversion (1988)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 92 (1988), S. 2316-2324 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100319a043
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  • 7
    Electronic Resource
    Electronic Resource
    Novel approach to efficient photoelectrochemical solar cells using electrolyte/discontinuous metal/semiconductor junctions (1986)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 90 (1986), S. 5495-5496 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100280a001
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructure of Trichoepithelioma Papulosum Multiplex (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cutaneous pathology 8 (1981), S. 0 
    Details
    ISSN: 1600-0560
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The following features of trichoepithelioma papulosum multiplex (TPM) were revealed by electron microscopy: 1. Proliferation of basaloid cells similar to that in basal cell epithelioma (BCE). 2. Abortive hair shafts and hair papillae. 3. Keratinous cysts surrounded by flat keratinocytes, the cytoplasm of which had small-sized keratohyalin and Odland's bodies. 4. Glycogen deposition near the nuclei, vacuoles filled with amorphous materials and lipid droplets in the cytoplasm of tumor cells. 5. Extracellular compartments, in which fibrous materials, cell fragments, and mucinous substance were found. 6. Melanocytes containing melanosomes in stage 11, Langerhans cells involving Birbeck's granules, Merkel cells and other dendritic cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0560.1981.tb00998.x
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  • 9
    Electronic Resource
    Electronic Resource
    The pathogenesis of the transepithelial elimination of the collagen bundles in acquired reactive perforating collagenosis (1996)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cutaneous pathology 23 (1996), S. 0 
    Details
    ISSN: 1600-0560
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Two cases of acquired reactive perforating collagenosis with poorly controlled diabetes mellitus were studied by histochemistry and by electron microscopy. In excoriated wounds, the necrotic mass on the bottom of the ulcer contained the collagen bundles which were continuous with the collagen bundles in the reticular layer. In the developing stage, the epidermis regenerated between the necrotic mass and the reticular dermis, and the collagen bundles in the reticular dermis were in continuity with those in the necrotic mass through the epithelial tunnels. The collagen in the epidermal channels did not degenerate ultra-structurally. In the mature lesion, collagen bundles being eliminated through the epidermis were surrounded by the fibroblasts at the basal cell layer. Collagen fibers were seen in the cytoplasm of these fibroblasts. From these findings, the mechanisms of the formation of the eruption in acquired reactive perforating collagenosis might be as follows: 1) In the developing stage, the regeneration of epidermis progresses between the necrotic mass and the reticular dermis, and among the collagen bundles. As a result, the collagen bundles remain in the channels of the epidermis. And then, 2) the regenerated epidermis makes the thick horny layer. As a result, the necrotic masses are lifted up and the collagen bundles are pulled up from the dermis through the epidermal channels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0560.1996.tb01429.x
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  • 10
    Electronic Resource
    Electronic Resource
    Electron microscopic investigation of transplanted squamous cell carcinoma in nude mice (1993)
    Springer
    Medical molecular morphology 26 (1993), S. 191-194 
    Details
    ISSN: 1860-1499
    Keywords: Squamous cell carcinoma ; Nude mice ; Transplantation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Extirpated specimens of a squamous cell carcinoma from a human thigh were transplanted to the subcutaneous tissue of nude mice. Fourteen days later, the transplanted tumor masses were, again, extirpated from the nude mice. The transplanted chimera of the squamous cell carcinoma as seen with the electron microscope resembled the tumor cells before transplantation. It is concluded that ultrastructural investigation of transplanted chimera from squamous cell carcinoma cases may be useful for examining the site of action and clinical effects of anticancer drugs on this kind of tumor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02347999
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