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Development of anti-G suits and their limitations   总被引:1,自引:0,他引:1  
Initial anti-G suits were based on the belief that decreased venous return was the critical effect of increased weight of blood during acceleration. Cumbersome water filled, pneumatic gradient or pulsatile pressure suits resulted. Subsequent centrifuge studies implicated arterial pressure, rather than venous return, as the major determinant of G tolerance in the sitting position. Consequently, methods of increasing arterial pressure were developed. Findings that the hypertensive, associated anti-blackout and discomfort effects of suit inflation all increase with bladder system pressure up to arterial occlusive levels resulted in the simplified G-suit used in W.W.II to the present. Recent +Gz loss of consciousness crashes indicate current straining maneuvers plus this suit are inadequate. Furthermore, because of very high pressures to maintain cerebral circulation in the sitting position, very high G suit protection is hazardous. If piloting is essential for full use of super performance fighters, the prone position with counter-weighted head support plus omni-directional surveilance is the surest strategem to obtain this advantage.  相似文献   
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BACKGROUND: Vitiligo is the most common pigmentary disorder with a global incidence from 0.1% to 2% in different geographical areas. Histopathology and histochemistry have shown the reduction of melanocytes in achromic patches, but microscopic changes of lesional and non-lesional skin are still not completely understood. Reflectance confocal microscopy (RCM), based on the different light reflectance index of cutaneous structures, allowed in vivo, en face microscopic evaluation of superficial skin layers with a resolution similar to skin histology. AIM: The purpose of this study was to evaluate RCM features of lesional and non-lesional skin of vitiligo patients. Moreover, re-pigmented areas were taken into consideration in order to evaluate melanocyte response to ultraviolet B (UVB) radiation. SUBJECTS AND METHODS: Sixteen patients of different phototypes affected by active non-segmental vitiligo and 10 controls were enrolled in the study. In vivo skin imaging was done using a commercially available RCM (Lucid, Vivascope 1500. Re-pigmented areas from 6 to 16 patients (after UVB narrow-band therapy) were also examined. RESULTS: Vitiligo lesions showed the disappearance of the bright rings normally seen at the dermo-epidermal junction. Moreover, non-lesional skin of vitiligo patients showed unexpected changes as the presence of half-rings or scalloped border-like features of the bright papillary rings. In re-pigmented areas after UVB narrow band therapy, the presence of activated, dendritic melanocytes was seen. CONCLUSIONS: Considering our results, and following further studies, RCM clinical applications could be used in the therapeutic monitoring and evaluation of the evolution of vitiligo.  相似文献   
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A morphological examination of synovial tissue from 25 patients with rheumatoid arthritis revealed that binucleated or multinucleated plasma cells were present in all samples and absent in synovia obtained from 16 control patients. Plasma cells containing two, three of four nuclei constitutet a mean 3% of the total plasma cell population. They were aways found amongst plasma cell infiltrates and in close association with small blood vessels. Ultrastructural analysis found no evidence of cellular membranes separating the individual nuclei in binucleated or multinucleated plasma cells, suggesting that the cells did not arise from fusion. Some of these plasma cells had a diameter approaching 100 μm, and many were in intimate contact with macrophages. The demonstration of a few cells with mitotic figures within the infiltrates suggests that the maintenance of plasma cell numbers in rheumatoid synovium may depend, in part, upon their local proliferation. Received: 25 August 1997 / Accepted: 2 October 1997  相似文献   
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A case of high grade B cell lymphoma presented with bone marrow necrosis, followed by development of extensive marrow fibrosis, the evolution of which was documented by serial magnetic resonance imaging and bone marrow trephine histology. A markedly raised anticardiolipin antibody titre at diagnosis suggests that lymphoma associated antiphospholipid syndrome may have contributed to the aetiology of the bone marrow necrosis.  相似文献   
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