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21.
We performed prenatal testing to predict the inheritance of choroideremia (CHM) using a linked polymorphic DNA marker, DXS95. DNA analysis of chorionic villi at the 12th week of pregnancy indicated that the allele at risk had not been passed from the heterozygous mother to the fetus. This prenatal exclusion of choroideremia was confirmed by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis. © 1992 Wiley-Liss, Inc.  相似文献   
22.
Using a newly devised 50-channel photometer which records the opacity of growing bacterial cultures, it was shown that the time taken by cultures diluted 1/1000 in fresh broth to reach 50% of the opacity of a fully grown culture was inversely related to the concentration of organisms in the original culture. This relation was used to determine the numbers of survivors after exposure to benzylpenicillin and gentamicin alone and in combination. The procedure is commended as a labour-saving and potentially rapid method of obtaining comprehensive information on the bactericidal action and interaction of antibiotics.  相似文献   
23.
Ischemia and anoxia are associated with decreased concentrations of cellular antioxidants. The hypothesis that recirculation of oxygenated blood to previously ischemic tissue may result in enhanced free-radical reactions leading to lipid peroxidation and tissue damage was investigated. Elevated hepatic conjugated diene concentrations were detected 60 min after treatment of rats with carbon tetrachloride, a positive control, but were not found after 90 min ischemia or at 5 or 60 min after reperfusion of ischemic tissue. These findings suggest that lipid peroxidation may not be an early event in ischemia-induced necrosis but do not rule out a role of other free-radical reactions in the pathogenesis of ischemic necrosis.  相似文献   
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Release of histamine (H) by ischemia-reperfusion injury was investigated in isolated rat hearts (Langendorff model). The effect of 10, 15, 20, 25, 30, 40 and 60 min ischemia (n=10 each) on H in the coronary effluent and in cardiac tissue was studied after 4 min reperfusion. Release of creatine kinase and lactate dehydrogenase in the coronary effluent increased with time of ischemia. Tissue H increased from 95±10 ng/g rat heart (mean±SEM) before ischemia to max 148±10 ng/g after 20 min ischemia (p<0.002), and increased also after 15 (p<0.01), 25 (p<0.01), 25 (p<0.01), and 30 min (p<0.045). H in the coronary effluent increased after 15 (from 16±3 to 26±2 pmol/min,p<0.044), 30 (26±6 pmol/min,p<0.027), and 60 min ischemia (47±6 pmol/min,p<0.0044). Release of H during ischemia-reperfusion is neither dependent on the severity of the ischemic insult, nor on the level of tissue H.  相似文献   
27.
The aims of this work were to measure the accuracy of one continuous speech recognition product and dependence on the speaker's gender and status as a native or nonnative English speaker, and evaluate the product's potential for routine use in transcribing radiology reports. IBM MedSpeak/Radiology software, version 1.1 was evaluated by 6 speakers. Two were nonnative English speakers, and 3 were men. Each speaker dictated a set of 12 reports. The reports included neurologic and body imaging examinations performed with 6 different modalities. The dictated and original report texts were compared, and error rates for overall, significant, and subtle significant errors were computed. Error rate dependence on modality, native English speaker status, and gender were evaluated by performing ttests. The overall error rate was 10.3 +/- 3.3%. No difference in accuracy between men and women was found; however, significant differences were seen for overall and significant errors when comparing native and nonnative English speakers (P = .009 and P = .008, respectively). The speech recognition software is approximately 90% accurate, and while practical implementation issues (rather than accuracy) currently limit routine use of this product throughout a radiology practice, application in niche areas such as the emergency room currently is being pursued. This methodology provides a convenient way to compare the initial accuracy of different speech recognition products, and changes in accuracy over time, in a detailed and sensitive manner.  相似文献   
28.
Recognition of Gram-positive bacteria by Toll-like receptor 2 (TLR2) induces activation of proinflammatory pathways. In mice, sensitization with the Gram-positive Propionibacterium acnes followed by a challenge with the TLR4 ligand, lipopolysaccharide (LPS), results in fulminant hepatic failure. Here, we investigated the role of TLR2 in liver sensitization to LPS-induced injury. Stimulation of Chinese hamster ovary cells and peritoneal macrophages with heat-killed P. acnes required expression of TLR2 but not of TLR4, suggesting that P. acnes was a TLR2 ligand. Cell activation by P. acnes was myeloid differentiation primary-response protein 88 (MyD88)-dependent, and it was augmented by coexpression of CD14 in mouse peritoneal macrophages. In vitro, P. acnes behaved as a TLR2 ligand and induced TLR4 hetero- and TLR2 homotolerance in peritoneal macrophages. In vivo priming of wild-type mice with P. acnes, but not with the selective TLR2 ligands peptidoglycan and lipotheicoic acid, resulted in hepatocyte necrosis, hyperelevated serum levels of tumor necrosis factor alpha (TNF-alpha), interleukin (IL)-6, interferon-gamma (IFN-gamma), and IL-12 (p40/p70), and increased RNA expression of proinflammatory cytokines (IL-12p40, IL-1alpha, IL-6, IL-1beta, IL-18, IFN-gamma) in the liver after a LPS challenge. Furthermore, P. acnes priming sensitized TLR2-deficient (TLR2-/-) but not MyD88-/- mice to LPS-induced injury, evidenced by hepatocyte necrosis, increased levels of serum TNF-alpha, IFN-gamma, IL-6, and liver proinflammatory cytokine mRNA expression. IFN-gamma, a cytokine sensitizing to endotoxin, was induced by P. acnes in splenocytes of TLR2-/- and TLR9-/- but not MyD88-/- mice. These results suggest that although P. acnes triggers TLR2-mediated cell activation, TLR2-independent but MyD88-dependent mechanisms mediate in vivo sensitization by P. acnes for LPS-induced liver injury.  相似文献   
29.
The hypothesis that acute ethanol uptake plus trauma can synergize to increase immunosuppression was tested. We found that, unlike non-alcohol-exposed patients, patients with acute alcohol use prior to trauma have a transient decrease in monocyte tumor necrosis factor (TNF) production during the very early postinjury (0–3 days) period. However, TNF production by these alcoholexposed patients' monocytes (MØ) became hyperelevated late postinjury (>9 days). Consequently, these massively elevated MØ TNF levels can contribute to posttrauma immunosuppression after acute alcohol use. We also demonstrate that normal monocyte activation with the superantigen,Staphylococcus enterotoxin B (SEB), results in a preferential induction of cellassociated MØ TNF production, described as characteristic of immunosuppressed trauma patients. Acutein vitro ethanol treatment down-regulated the elevated TNF production by trauma patients' MØ after either SEB, muramyl-dipeptide (MDP), interferon- plus MDP, or lipopolysaccharide (LPS) stimulation. Both SEB- and LPS-induced TNF mRNA induction was inhibited by acute alcohol treatment in normal MØ, indicating that ethanol can regulate cytokine gene expression. An additional immunosuppressive effect of acute ethanol's stimulation was suggested by its induction of elevated transforming growth factor production in trauma patients' activated MØ.  相似文献   
30.
Summary: The age-associated changes in humoral Immunity affect the quality more than the quality of the antibody response. Changes in the quality of the antibody response with age include shifts in antibody specificities from foreign to autoantigens. in antibody isotypes from IgG to IgM, in antibody affinities from HIGH to low and in the antibody idiotypic repertoire. These changes can be traced to an impaired capacity of T cells to facilitate: (a) the maturation of B cells respect to isotype and affinity maturation in the periphery and (b) the development of a diverse B-cell repertoire from precursors within the bone marrow. In contrast, there is no evidence that the amount of immunoglobulin produced before or after immunization diminishes with age. Nonetheless, the impaired responses of the elderly to most vaccines and the greater susceptibility of the elderly to infections has fostered a view that immune senescence leads to a state of immune deficiency. However, it is more precise to describe immune senescence as leading to a state of immune dysregulation. The dysregulation of the humoral immunity is manifested by a shift from adaptive humoral Immunity, characterized by the production of a highly specific, high-affinity, IgG antibody response to foreign antigens, to a process of natural antibody-mediated immunity, dominated by low-affinity, polyreactive, IgM antibodies which react with autoantigens, Age-associated T-cell impairments appear to be the basis for the shift from adaptive to natural humoral immunity and their reversal should permit the restoration of an adaptive antibody response in the elderly.  相似文献   
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