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991.
When pure-tone acoustic masking stimuli of various frequencies were presented simultaneously with electrical stimuli applied to cochlear nucleus, only those maskers within a limited frequency range interfered with the detection of the electrical stimuli. The form of the masking functions obtained suggest that the electrical stimulus directly activated only a small population of neurons which were functioning in a tonotopic fashion. 相似文献
992.
993.
GM O'Hanlon GJ Paterson J Veitch G Wilson HJ Willison 《Canadian Metallurgical Quarterly》1998,95(6):605-616
A series of monoclonal IgM anti-GM1 ganglioside antibodies has been cloned from peripheral blood lymphocytes of patients with multifocal motor neuropathy and Guillain-Barré syndrome. In solid-phase immunoassay, the antibodies react with GMI, and also in differing degrees to the structurally related glycolipids asialo-GM1 (GA1) and GD1b. Here we describe the binding patterns of six human anti-GM I antibodies to epitopes within the human nervous system. Antibodies were observed to bind to motor neurons and spinal grey matter, dorsal and ventral spinal roots, dorsal root ganglion neurons, nodes of Ranvier, neuromuscular junctions and skeletal muscle. The distribution of immunoreactive epitopes, which included sensory structures, extended beyond those sites conventionally regarded as pathologically affected in anti-GM1 antibody-associated motor nerve syndromes. This undermines a model of disease pathogenesis based solely on antigen distribution. Factors other than the presence or absence of antigen, such as the local ganglioside topography, antibody penetration into, and pathophysiological vulnerability of a particular site may also influence the clinicopathological outcome of anti-GM1 antibody-mediated autoimmune attack. 相似文献
994.
A Kawano HL Seldon GM Clark RT Ramsden CH Raine 《Canadian Metallurgical Quarterly》1998,118(3):313-326
Glycosyl-phosphatidylinositol (GPI) lipids have a structural role as protein anchors to the cell surface. In addition, they are implicated in hormone, growth factor and cytokine signal transduction. Their phosphodiesteric hydrolysis mediated by an activated phospholipase results in the generation of water soluble oligosaccharide species termed the inositol phosphoglycan (IPG). This product has been demonstrated to possess biological properties when added exogenously to cells mimicking the biological effects of a variety of extracellular ligands. This may be accomplished since IPG is generic for a family of closely related species which are released in a tissue-specific manner and additionally have cell-specific targets. Micro-organic synthesis has recently been able to shed new light on this topic by the introduction of defined oligosaccharide analogues of IPG for the assessment of their biological activity. These have complemented the findings observed with purified IPG from biological sources thus strengthening the belief that the GPI/IPG signalling system represents a truly novel aspect of transmembrane signalling. 相似文献
995.
WJ O'Donnell W Pieciak GM Chertow J Sanabria KC Lahive 《Canadian Metallurgical Quarterly》1998,114(5):1264-1268
STUDY OBJECTIVES: To determine the feasibility of repeat sputum induction in acute Pneumocystis carinii pneumonia (PCP) and to define the rate of clearance of P carinii cysts from the respiratory tract of HIV-seropositive patients with acute PCP. DESIGN: Prospective cohort evaluation. SETTING: University medical center. PARTICIPANTS: Twenty-four HIV-seropositive subjects with acute PCP. MEASUREMENTS: Sputum induction for P carinii 2, 3, 4, and 6 weeks after initial diagnosis, and follow-up for 1 year. RESULTS: Eighty-eight percent of subjects had residual cysts at 2 weeks, 76% at 3 weeks, 29% at 4 weeks, and 24% at 6 weeks postdiagnosis. A prior AIDS-defining illness (p = 0.033) or prior PCP (p = 0.004) predicted relapse within 6 months, but persistent cysts at 3 weeks did not; 8 of 16 sputum-positive subjects and 1 of 5 sputum-negative subjects experienced a relapse within 6 months (p = 0.34). Secondary prophylaxis with trimethoprim-sulfamethoxazole was associated with a reduced risk of relapse. CONCLUSIONS: Serial sputum induction coupled with direct fluorescent antibody staining is a feasible, noninvasive method of respiratory tract surveillance for the eradication of P carinii during and after acute PCP. Three-quarters of HIV-seropositive patients with acute PCP have persistent cysts in their lungs at the end of antimicrobial treatment, despite clinical recuperation, but only one quarter have residual cysts 6 weeks postdiagnosis. A prior AIDS-defining illness and prior PCP are positively associated, and subsequent trimethoprim-sulfamethoxazole prophylaxis is negatively associated, with relapse within 6 months, while persistent organisms at 3 weeks do not appear to be a significant predictor of relapse risk. 相似文献
996.
TA King GJ Cederbom JL Champaign DH Smetherman JS Bolton GH Farr WM McKinnon RR Kuske GM Fuhrman 《Canadian Metallurgical Quarterly》1998,176(6):497-501
To evaluate whether the type of weight-bearing loading subjected to the skeleton during horseback-riding was associated with differences in bone mass and muscle strength of the thigh, we investigated bone mass and isokinetic muscle strength in 20 female horse riders (age 17.9 +/- 0.6 years) who were riding 7.0 +/- 3.4 hours/week, and 20 nonactive females (age 17.8 +/- 1.1 years). The groups were matched according to age, weight, and height. Areal bone mineral density was measured in total body, head, lumbar spine, right femoral neck, Ward's triangle, and trochanter, the whole dominant and nondominant humerus, and in specific sites in the right femur diaphysis, distal femur, proximal tibia, and tibia diaphysis using dual X-ray absorptiometry. Isokinetic concentric and eccentric peak torque of the quadricep and hamstring muscles were measured using an isokinetic dynamometer. There were no significant differences in bone mass between the horseback riders and nonactives at any site measured. The horse riders were significantly (P < 0.05-0.01) stronger in concentric hamstrings strength at 90 degrees/second and 225 degrees/second and in eccentric quadricep and hamstring strength at 90 degrees/second. Horseback riding in young females is associated with a high muscle strength of the thigh, but not with a high bone mass. 相似文献
997.
A task force of periodontists established clinical and histologic outcomes (goals) for the treatment of intrabony defects and researched the literature for techniques that would most predictably achieve these goals. The group also identified factors that could influence predictability. The treatment outcomes selected by the task force included regeneration of a true attachment apparatus; gain in bone and probing attachment levels; reduction in probing pocket depth; minimal gingival recession; increased patient comfort; esthetic appearance and state of wellness; and maintenance of health, comfort, and function over time. Based on evidence, it was concluded that guided tissue regeneration, guided tissue regeneration combined with the use of decalcified freeze dried bone allografts and freeze-dried bone allografts alone are the most predictable regenerative procedures for achieving selected treatment outcomes. Various factors, such as patient characteristics, the morphology of the defect, and the surgical technique can influence the healing response of intrabony defects. Patient factors, such as plaque control, compliance, and cigarette smoking, can directly affect predictability of periodontal regeneration. Defect selection is critical, and deep and narrow defects are the most predictable response to regenerative procedures. The number of remaining bony walls is important in grafting procedures, but their influence is questionable in guided tissue regeneration. Various technical procedures, such as flap design, defect debridement, and wound protection, may influence the predictability of regeneration. 相似文献
998.
Is elderly care nursing a specialty? This paper reports results from an interview-based study which aims to uncover the distinctive elements of nursing work with elderly people. Within the context of sociological literature on specialism it is concluded that a case for seeing elderly care nursing as a specialty area can be made. However, that case has implications for the continued marginalization of elderly people in society. 相似文献
999.
GM Janssen HT van Damme J Kriek R Amons W M?ller 《Canadian Metallurgical Quarterly》1994,269(50):31410-31417
Elongation factor 1 (EF-1) regulates the specific interaction of aminoacyl-tRNA with the ribosome during the elongation phase of protein biosynthesis. Although individual functions of its separate chains have been well defined, to date there is hardly information about the structure and function of the whole complex. We describe here the complete subunit structure of elongation factor 1, and discuss its change during development of Artemia. Elongation factor 1 consists of a pentameric complex, composed of four different subunits alpha, beta, gamma, and delta in a molar ratio of 2:1:1:1. Although one molecule of EF-1 alpha dissociates easily from the complex EF-1 alpha 2 beta gamma delta under the influence of aminoacyl-tRNA and GTP, the second molecule of EF-1 alpha was found to remain firmly attached. Thus, in eukaryotic protein synthesis, movement of transfer RNAs to the ribosome seems under the influence of two distinct molecules of EF-1 alpha, a result possibly related to the presumed consumption of two molecules of GTP by EF-Tu during the elongation step of prokaryotic protein synthesis. 相似文献
1000.