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FM sonography - a signal-processing technique that uses frequency and phase information as well as amplitude data - shows promise in evaluation of patients with diffuse liver disease. In a prospective blinded review of 37 patients with biopsy-proved liver disease and 42 healthy volunteers, FM sonography was clearly superior to traditional amplitude-based (AM) sonography in distinguishing healthy from diseased subjects. Statistically significant differences were seen in accuracy (FM, 98.7%; AM, 84.8%), sensitivity (FM, 97.3%; AM, 70.3%), and negative predictive value (FM, 97.7%; AM, 78.8%). Our data also suggest that current FM sonographic techniques cannot differentiate among histologic findings associated with different hepatic parenchymal abnormalities. It is unclear, therefore, whether FM imaging can reduce the numbers of patients who require biopsy for diagnosis or the frequency of biopsy procedures in patients with known disease.  相似文献   
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抑制幽门螺杆菌产生的脲酶具有治疗胃炎和消化性溃疡的作用。用酚红指示剂和Berthelot试剂在96孔培养板上检测重组脲酶活性,其灵敏度指标酚红法每mg酶蛋白引起的每分钟吸光度变化。△A为6.9,而Berthelot法每mg酶蛋白引起的每分钟吸光度比值变化△A为313。结果表明用Berthelot试剂检测重组脲酶活性适宜在96孔培养板上大规模筛选天然产物中的脲酶抑制剂。  相似文献   
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While there is growing awareness for the need to examine the etiology of problem behaviors across cultural, racial, socioeconomic, and gender groups, much research tends to assume that constructs are equivalent and that the measures developed within one group equally assess constructs across groups. The meaning of constructs, however, may differ across groups or, if similar in meaning, measures developed for a given construct in one particular group may not be assessing the same construct or may not be assessing the construct in the same manner in other groups. The aims of this paper were to demonstrate a process of testing several forms of equivalence including conceptual, functional, item, and scalar using different methods. Data were from the Cross-Cultural Families Project, a study examining factors that promote the healthy development and adjustment of children among immigrant Cambodian and Vietnamese families. The process described in this paper can be implemented in other prevention studies interested in diverse groups. Demonstrating equivalence of constructs and measures prior to group comparisons is necessary in order to lend support of our interpretation of issues such as ethnic group differences and similarities.  相似文献   
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Steroid 21-hydroxylase deficiency is among the most common inborn errors of metabolism in man. Characterization of mutations in the 21- hydroxylase gene (CYP21) has permitted genetic diagnosis, facilitated by the polymerase chain reaction (PCR). The most common mutation is conversion of an A or C at nt656 to a G in the second intron causing aberrant splicing of mRNA. Homozygosity for nt656G is associated with profoundly deficient adrenal cortisol and aldosterone synthesis, secondary hypersecretion of adrenal androgens, and a severe form of congenital adrenal hyperplasia (CAH) characterized by ambiguous genitalia and/or sodium wasting in newborns. During the course of genetic analysis of CYP21 mutations in CAH families, we and others have noticed a number of relatives genotyped as nt656G homozygotes, yet showing no clinical signs of disease. A number of lines of evidence have led us to propose that the putative asymptomatic nt656G/G individuals are incorrectly typed due to dropout of one haplotype during PCR amplification of CYP21. For prenatal diagnosis, we recommend that microsatellite typing be used as a supplement to CYP21 genotyping in order to resolve ambiguities at nt656.   相似文献   
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Bovine NK cells have recently been characterized and the present study describes the interaction between NK cells, antigen-presenting cells, and secreted mycobacterial proteins. Gamma interferon (IFN-gamma) production by NK cells was seen in approximately 30% of noninfected calves in response to the Mycobacterium tuberculosis complex-specific protein ESAT-6, MPP14 from Mycobacterium avium subsp. paratuberculosis, and purified protein derivative (PPD) from M. tuberculosis. In contrast, no response was induced by MPB70, which is another M. tuberculosis complex-specific secreted antigen. The production of IFN-gamma by NK cells in whole blood in response to ESAT-6 and MPP14 was demonstrated using intracellular staining together with surface labeling for the NK cell-specific receptor, NKp46, or CD3. Furthermore, the depletion of NK cells from peripheral blood mononuclear cells completely abolished the IFN-gamma production. The response was mediated through stimulation of adherent cells and was largely independent of contact between adherent cells and the NK cells. Neutralization of interleukin-12 only partly inhibited IFN-gamma production, showing that other cytokines were also involved. The demonstration of NK cell-mediated IFN-gamma production in young cattle provides an explanation for the nonspecific IFN-gamma response frequently encountered in young cattle when using the IFN-gamma test in diagnosis of mycobacterial infections.  相似文献   
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Anthropogenic environmental change will heavily impact cities, yet associated health risks will depend significantly on decisions made by urban leaders across a wide range of non-health sectors, including transport, energy, housing, basic urban services, and others. A subset of planetary health researchers focus on understanding the urban health impacts of global environmental change, and how these vary globally and within cities. Such researchers increasingly adopt collaborative transdisciplinary approaches to engage policy-makers, private citizens, and other actors in identifying and evaluating potential policy solutions that will reduce environmental impacts in ways that simultaneously promote health, equity, and/or local economies—in other words, maximising ‘co-benefits’. This report presents observations from a participatory workshop focused on challenges and opportunities for urban planetary health research. The workshop, held at the 16th International Conference on Urban Health (ICUH) in Xiamen, China, in November 2019, brought together 49 participants and covered topics related to collaboration, data, and research impact. It featured research projects funded by the Wellcome Trust’s Our Planet Our Health (OPOH) programme. This report aims to concisely summarise and disseminate participants’ collective contributions to current methodological practice in urban planetary health research.  相似文献   
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