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151.
DNA replication is completed in Saccharomyces cerevisiae cells that lack functional Cdc14, a dual-specificity protein phosphatase 总被引:2,自引:0,他引:2
A 35-year-old man affected with pulmonary sarcoidosis had a 12-year history of fatigue and pain in the limbs, with normal neurological examination, except for diffusely absent deep tendon reflexes. Muscle biopsy samples showed multiple noncaseating granulomas, most prominent around the intramuscular nerves, with predominance of CD4+ cells. Intramuscular nerve bundles surrounded by granulomas were immunolabelled with laminin alpha1, alpha2, beta1 and gamma1 chain, and collagen IV. Sural nerve biopsy samples were normal. This patient showed a unique histopathological pattern of sarcoid neuromyopathy characterized by distribution of granulomas or infiltrating cells around intramuscular nerve fibers. The clinical picture, restricted to nonspecific symptoms of fatigue and myalgia, and loss of deep tendon reflexes, correlated well with the selective localization of sarcoid lesions in contiguity with the intramuscular nerves. To our knowledge, this peculiar clinico-pathological correlation has not been reported previously. 相似文献
152.
J Wong B Johnston SS Lee DC Bullard CW Smith AL Beaudet P Kubes 《Canadian Metallurgical Quarterly》1997,99(11):2782-2790
A two-step paradigm for leukocyte recruitment has been established in a number of tissues including the mesentery, skin, and muscle, and necessitates an initial rolling step via the selectins before firm leukocyte adhesion via the integrins. In view of the many inflammatory diseases that involve the liver, we investigated the importance of rolling and the selectins in the hepatic microvasculature and compared the responses to that of the commonly used mesentery or cremaster microvasculature. We visualized the liver microvasculature using intravital microscopy and we determined that within the liver the majority of leukocytes adhere within the sinusoids (80%) in response to a chemotactic stimulus such as FMLP (20% in postsinusoidal venules) whereas leukocytes adhere exclusively within postcapillary venules in tissue like the mouse cremaster. In the sinusoids, the adhesive response to FMLP is not dependent upon selectins inasmuch as adhesion was not reduced in the sinusoidal vessels of P-selectin-deficient mice or E-selectin/P-selectin- deficient animals in the presence or absence of L-selectin antibody. No rolling or adhesion was detected in response to FMLP in the selectin-deficient cremaster microvasculature. Immunoneutralization of selectins with fucoidan in wildtype mice eliminated rolling and adhesion in the cremaster but failed to affect adhesion in the liver sinusoids in response to FMLP. More long-term leukocyte recruitment with lipopolysaccharide (4 h) was also impaired in the cremaster but not the liver microvasculature in selectin-deficient animals. Leukocyte adhesion in the sinusoids was reduced in P-selectin-deficient mice also lacking intercellular adhesion molecule-1 (ICAM-1). This study for the first time demonstrates that selectins are not an essential step for leukocyte recruitment into the inflamed liver microvasculature. 相似文献
153.
Building on the huge success of its homegrown cellular system, Europe is planning a next-generation wireless system to handle data as well as voice, and-it is hoped-lay the foundation for universal roaming. The system being developed in the framework of the European Telecommunications Standards Institute (ETSI) is called UMTS (Universal Mobile Telecommunication System). In parallel, the International Telecommunication Union, based in Geneva, is formulating IMT (International Mobile Telecommunications) 2000, which is to be a family of systems that will let users roam worldwide with the same handset, and which will include UMTS as a subset 相似文献
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157.
The purpose of this study was to describe the physiological responses of premature infants to an acute tissue-damaging stimulus and to determine how severity of illness and behavioral state influenced these responses. The physiological responses (heart rate, oxygen saturation, and intracranial pressure) of a convenience sample of 124 premature infants between 32 and 34 weeks gestational age were described during four phases of a routine heel stick procedure. Analysis of the results showed a significant multivariate main effect of phase on the group of physiological responses. Behavioral state was found to influence the physiological responses, but severity of illness did not. 相似文献
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159.
Observation learning in day-old chicks using a one-trial passive avoidance learning paradigm 总被引:1,自引:0,他引:1
The ATP-binding cassette (ABC) transporters belong to a large superfamily of proteins which share a common function and a common nucleotide-binding domain. The CvaB protein from Escherichia coli is a member of the bacterial ABC exporter subfamily and is essential for the export of the peptide antibiotic colicin V. Here we report that, surprisingly, the CvaB carboxyl-terminal nucleotide-binding domain (BCTD) can be preferentially cross-linked to GTP but not to ATP at low temperatures. The cross-linking is Mg2+ and Mn2+ dependent. However, BCTD possesses similar GTPase and ATPase activities at 37 degrees C, with the same kinetic parameters and with similar responses to inhibitors. Moreover, a point mutation (D654H) in CvaB that completely abolishes colicin V secretion severely impairs both GTPase and ATPase activities in the corresponding BCTD, indicating that the two activities are from the same enzyme. Interestingly, hydrolysis activity of ATP is much more cold sensitive than that of GTP: BCTD possesses mainly GTP hydrolysis activity at 10 degrees C, consistent with the cross-linking results. These findings suggest a novel mechanism for an ABC protein-mediated transport with specificity for GTP hydrolysis. 相似文献
160.
A two-story, steel moment frame building that was severely damaged during the Northridge earthquake (1994) is studied in detail. Immediately following the earthquake, the building was judged unsafe for occupancy due to a residual displacement of 7.6 cm (3 in.) in the first story. Opening of the exterior facade revealed severe cracking in the moment connections. All connections contained cracks that started in the weld at the bottom flange of the beam and propagated across the column flange and into the column panel zone. Four welded, beam-to-column, moment connections were taken from the building for additional cyclic testing under controlled conditions in the laboratory to evaluate their residual strength and deformation capacity. Results indicate that the badly damaged specimens still have significant residual strength and deformation capacity. All damaged specimens were tested to 3% rotation. 相似文献