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排序方式: 共有7251条查询结果,搜索用时 15 毫秒
31.
J M Reilly G H Ballantyne F X Fleming K A Zucker I M Modlin 《The American surgeon》1990,56(3):119-123
Survival rates from colorectal cancer will rise only when polyps and cancers are found at an earlier, curable stage. Consequently, the purpose of the present study was to compare the yield of colonic neoplasms from flexible sigmoidoscopy and colonoscopy with that from occult blood testing. Results from 474 flexible sigmoidoscopies and 1,115 colonoscopies were prospectively recorded during a four-year study period. Colorectal polyps were found in 111 (23.4%) patients undergoing flexible sigmoidoscopy and 325 (29.1%) patients undergoing colonoscopy. Among the 436 patients with polyps, the occult blood test was negative in 282 (64.7%). Among the 51 patients with colorectal cancers, the occult blood test was negative in 20 (39.1%). Thus, testing for occult blood missed the majority of polyps and a large percentage of the carcinomas. These data indicate that lower gastrointestinal endoscopy is superior to occult blood testing as a screening test for detecting colorectal polyps or cancers. Furthermore, given the high incidence of neoplasia in this patient population, the authors suggest that colonoscopy become the screening test of choice for colorectal cancer. 相似文献
32.
Uroscopy in the 21st century: high-field NMR spectroscopy 总被引:1,自引:1,他引:0
Neild GH; Foxall PJ; Lindon JC; Holmes EC; Nicholson JK 《Nephrology, dialysis, transplantation》1997,12(3):404-417
From the experiments described, it can be seen that there are different
research approaches that can be taken and these are summarized in Table 1.
Whereas much scientific research is principally hypothesis led, there
remains, nevertheless, an important place for exploratory research. High
resolution NMR can measure, directly and simultaneously, a wide range of
endogenous metabolites in biological fluids and has the unique capability
of providing structural information on the metabolites detected. It has
proved to be a powerful research tool with which to study inherited
metabolic diseases, renal disease, drug metabolism, and toxicity, and can
be used to monitor the effects of drug therapy. For instance, by using a
library of experimental toxins one can map the metabolic profile of
site-specific nephron injury. With this approach in man one could
eventually take an unknown disease such as Balkan nephropathy and predict
the initial site of tubular injury, the mode of injury and therefore the
kind of toxin capable of producing that injury. NMR spectroscopic
techniques are still advancing rapidly, with ever increasing sensitivity
and sophistication of NMR pulse sequences to enhance structural elucidation
in complex mixtures. Given the advances in directly coupled HPLC-NMR and
even HPLC-NMR-mass spectroscopy it is likely that these technologies in
conjunction with pattern recognition will make major contribution to our
understanding of renal processes and provide new diagnostic insights in the
21st century.
相似文献
33.
Leukotriene B4 (LTB4) and the protein kinase C activator, 4-beta-phorbol dibutyrate (PDBu), both induced a pronounced and concentration-dependent stimulation of hydrogen peroxide (H2O2) generation by purified guinea pig peritoneal eosinophils in the concentration range 1 nM-1 microM. The LTB4 response was inhibited competitively by the specific LTB4 receptor antagonist, U-75302, with a KB of 25 nM, while the concentration-response curves for both stimuli were shifted rightwards (3.8-fold and 2.8-fold for LTB4 and PDBu, respectively) by the competitive protein kinase C inhibitor, 1-O-hexadecyl-2-O-methylglycerol at a concentration of 300 microM. LTB4 appears, therefore, to induce respiratory burst in eosinophils via a receptor-mediated mechanism involving protein kinase C. 相似文献
34.
Background
The efficacy of academic detailing in changing physicians' knowledge and practice has been the subject of many primary research publications and systematic reviews. However, there is little written about the features of academic detailing that physicians find valuable or that affect their use of it. The goal of our project was to explore family physicians' (FPs) perceptions of academic detailing and the factors that affect their use of it. 相似文献35.
Tumours of the kidney with sarcomatoid elements are uncommon. The radiological findings in 11 patients with such lesions are presented. It is important to separate pure sarcomas from lesions with sarcomatous and carcinomatous elements since they have different radiological appearances and prognosis. These tumours often show calcification on radiographs and on angiography appear predominantly avascular with a blood supply from capsular vessels. Because of their rarity and the overlap of radiographic findings with more common tumours the diagnosis cannot be made by current imaging methods alone. 相似文献
36.
In this article we review some of the hormonal, sensory and experiential factors that regulate the onset and early maintenance of maternal responsiveness in rat and human mothers. We discuss data suggesting that, in humans, pregnancy is associated with changes in feelings and attitudes that may bear on adjustment to motherhood postpartum. Preliminary studies indicate that these changes are probably not hormonally mediated but are associated with a variety of psychosocial factors. Once women give birth, there is some suggestion that they undergo a period of elevated "responsiveness" which may be influenced by puerperal hormones and during which experiences with the newborn take on a special salience. Following the early postpartum period, a variety of factors influence maternal responsiveness, including the mother's affective state, her social relationships, and experiences caring for young. We discuss the relative contributions of psychological and physiological influences to maternal responsiveness at different stages of the maternity cycle. 相似文献
37.
Maxillary resection defects have traditionally been technically difficult to treat with conventional radiation therapy. The irregular contours of the defect lead to an uneven distribution of the radiation doses. The potential to undertreat defects of microscopic involvement may leave residual disease. Tissue morbidity is high at isolated "hot spots" or at locations of excessive dose distribution. The use of a water-filled balloon bolus in conjunction with a balloon-retaining stent can significantly improve treatment efficacy and decrease tissue morbidity. This article describes a technique for the fabrication of a balloon-retaining stent for an orocutaneous defect. 相似文献
38.
The Pall LG6 arterial line filter has been designed to remove free circulating leukocytes from the arterial line of the extracorporeal circuit employed in openheart surgery. The filter was evaluated and compared to a control filter (Pall Stat-Prime) in terms of its general blood handling characteristics, particularly with regard to the associated level of leukocyte removal. The gross air handling characteristics of the filters were also assessed together with pressure drop. It was found that the filters differed little in terms of all factors studied other than the level of leukocyte depletion. The LG6 filter was associated with substantial levels of leukocyte depletion, particularly the depletion of neutrophils. Over the 90 minute perfusion period the LG6 filter was found to be associated with a neutrophil depletion rate of around 70% while preferentially sparing lymphocytes. This compared to a 10-20% depletion rate in the control filter. This was achieved without apparently compromising the performance of the filter in terms of the other factors studied. 相似文献
39.
Emery M Rodgers MM Boerman J Fleming BC Howe J Pope M 《The Journal of orthopaedic and sports physical therapy》1989,10(11):441-447
This research was supported by a grant from The Foundation for Physical Therapy, Alexandria, VA. The purpose of this study was to determine the reliability of a quantitative measure of knee ligament laxity in vivo. The testing device simultaneously measures applied forces and resulting displacement at the knee through use of a multidimensional electrogoniometer, dynamometer, and a computer-assisted analysis system. Subjects were 30 females and 20 males, ranging in age from 18-32 years. Laxity tests were performed in the anterior/posterior (A/P) plane at 90 and 30 degrees of knee flexion, and the varus/valgus (V/V) plane at 20 and 0 degrees of knee flexion. Test-retest (N = 41) and intertester (N = 18) repeatability was assessed in all test positions by ANOVA and by coefficients of correlation and variability. No significant differences were found within testers for A/P or V/V tests 1 week apart at any angle tested. There were significant differences between testers for A/P and V/V tests. No significant differences were found between left and right sides, or between male/female values. Comparisons to other in vitro and in vivo studies are made. J Orthop Sports Phys Ther 1989;10(11):441-447. 相似文献
40.
The present study examined the withdrawal process for adolescents who had attempted to quit smoking. A sample of 622 6th through 12th graders were interviewed. Smoking status was reported prior to attempting to quit and its relationship with the withdrawal experience was evaluated. Although over half of those who smoked regularly reported trying to quit, 78% of the "quitters" were smoking six months after their quit attempt. Experiencing adverse withdrawal symptoms was related to smoking at daily levels before quitting; delaying trying to quit was associated with initiation of smoking at an early age; and quitting success was predicted by early quitting age, lower pre-quitting smoking levels, a lack of a prior quitting failure, and peer smoking. The results suggest that smoking intervention programs for adolescents should include components facilitating the quitting process that take into consideration youngsters' smoking and quitting histories. 相似文献