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排序方式: 共有485条查询结果,搜索用时 29 毫秒
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P F Ludman M Darby N Tomlinson P A Poole-Wilson S Rees 《Journal of computer assisted tomography》1992,16(5):795-803
To gauge the accuracy of ultrafast CT in measuring cardiac output and myocardial perfusion in humans, measurements of continuous and pulsatile flow were made in a large asymmetrical phantom. The variation in the relationship between Hounsfield number and contrast concentration was assessed in a human thorax phantom. Radiopaque contrast medium was injected during perfusion of the phantom at a range of flow rates between 1.5 and 8 L/min. The phantom was scanned in two modes (50 and 100 ms) during continuous and pulsatile flow and with the phantom surrounded by air and by water. Flow in the tubes was calculated using indicator dilution theory, and flow in the tissue-equivalent chamber was calculated by applying first-pass distribution principles. The standard deviation of the difference between calculated and measured flow varied from 0.2 to 0.6 L/min, giving 95% limits of agreement from 0.4 to 1.2 L/min. The constant (K) relating Hounsfield unit number to iodine concentration varied widely both in different locations within the phantom and under different scan conditions (17.2-27.6 HU/mg I). Within a human thorax phantom, K varied from 14.15 to 23.18 HU/mg I and was dependent on location within the thorax phantom, the scan mode, and the cross-sectional diameter of the phantom. These data suggest that though the ultrafast CT scanner can measure continuous and pulsatile flow accurately in tubes, precise measurements of cardiac output in humans will require K to be assessed for each subject. Measurements of flow in tissue should be possible. 相似文献
3.
4.
Ludman E Katon W Bush T Rutter C Lin E Simon G Von Korff M Walker E 《Psychological medicine》2003,33(6):1061-1070
BACKGROUND: A randomized trial of a primary care-based intervention to prevent depression relapse resulted in improved adherence to long-term antidepressant medication and depression outcomes. We evaluated the effects of this intervention on behavioural processes and identified process predictors of improved depressive symptoms. METHOD: Patients at high risk for depression recurrence or relapse following successful acute phase treatment (N=386) were randomly assigned to receive a low intensity 12-month intervention or continued usual care. The intervention combined education about depression, shared decision-making regarding use of maintenance pharmacotherapy and cognitive-behavioural strategies to promote self-management. Baseline, 3, 6, 9 and 12-month interviews assessed patients' self-care practices, self-efficacy for managing depression and depressive symptoms. RESULTS: Intervention patients had significantly greater self-efficacy for managing depression (P<0.01) and were more likely to keep track of depressive symptoms (P<0.0001), monitor early warning signs (P<0.0001), and plan for coping with high risk situations (P<0.0001) at all time points compared to usual care control patients. Self-efficacy for managing depression (P<0.0001), keeping track of depressive symptoms (P=0.05), monitoring for early warning signs (P=0.01), engaging in pleasant activities (P<0.0001) and engaging in social activities (P<0.0001) positively predicted improvements in depression symptom scores. CONCLUSIONS: A brief intervention designed to target cognitive-behavioural factors and promote adherence to pharmacotherapy in order to prevent depression relapse was highly successful in changing several behaviours related to controlling depression. Improvements in self-efficacy and several self-management behaviours that were targets of the intervention were significantly related to improvements in depression outcome. 相似文献
5.
Glycoproteins present in human follicular fluid that inhibit the zona- binding capacity of spermatozoa 总被引:1,自引:0,他引:1
Previous studies have suggested that human follicular fluid contains
factors that reduce the zona-binding capacity of spermatozoa. The present
study provides further evidence of the existence of such factors. Using the
hemizona binding assay (HZA), we have shown that the inhibitory effect of
human follicular fluid on the zona-binding capacity of spermatozoa is
concentration-dependent, an inhibitory effect being detected when the
concentration of human follicular fluid was > or = 10%. A 1%
concentration of human follicular fluid did not possess this inhibitory
activity. Heating human follicular fluid at 56 degrees C for 30 min did not
affect its inhibitory properties; treatment with proteinase-K abolished
such inhibition. Human follicular fluid was fractionated sequentially by
concanavalin-A affinity chromatography, Mono Q ion-exchange chromatography
and Superose-12 gel filtration. The zona binding inhibitory activity
resided in the fraction which bound to the lectin and Mono Q column and
contained molecules with native molecular weights of 32 and 192 kDa. Sodium
dodecyl sulphate-polyacrylamide gel electrophoresis analysis suggested that
the 192 kDa glycoprotein was a tetramer, while the 32 kDa glycoprotein
remained as a single molecular species under denaturing conditions. We
conclude that two glycoproteins were responsible for the zona binding
inhibitory activity of human follicular fluid. The physiological role of
these factors remains unclear.
相似文献
6.
We describe a mother and daughter with a distinct phenotype that is different from previous reports. This is likely to constitute a new syndrome for which we propose the mnemonic GMS for G goniodysgenesis, M mental deficiency, and S short stature. The pattern of occurrence is compatible with either autosomal dominant or X-linked inheritance. 相似文献
7.
To increase mammography participation, the authors implemented an outreach intervention translating concepts from expectancy value theory into a motivational interviewing telephone intervention that included the opportunity to schedule a screening appointment. Process data are presented from 491 women who had not scheduled a mammogram within 2 months of receiving a mailed invitation from a managed care organization's centralized breast cancer screening program. A total of 83% of targeted women accepted the counseling calls. Counselors rated 84% of completed calls as either receptive or neutral in tone. Women with prior mammography experience were more likely to be receptive and to schedule a screening appointment during the calls than were women with no prior experience. Topics discussed during the calls also differed between women with and without prior mammography experience. Implications for dissemination of counseling interventions in health care organizations are discussed. 相似文献
8.
MW Lieberman R Barrios G Kala SV Kala ED Lykissa CN Ou 《Environmental health perspectives》1999,107(9):A444-A445
Respond on comments on Lieberman's article: Cyclosiloxanes Produce Fatal Liver and Lung Damage in Mice. Environ Health Perspect 107:161-165 相似文献
9.
C M McBride D Scholes L C Grothaus S J Curry E Ludman J Albright 《Preventive medicine》1999,29(2):133-138
OBJECTIVE: This study was undertaken to evaluate a smoking cessation intervention provided to women smokers as follow-up to cervical cancer screening. METHODS: Women who had had a Pap test in the prior month (N = 4,053) were called to complete a survey that assessed smoking status; 580 identified smokers were randomized to receive Usual care (n = 292) or a Self-help intervention (n = 288) that included a self-help booklet, a smoking and reproductive health information card, and three telephone counseling calls. Women were followed up at 6 and 15 months post-base line. RESULTS: Cessation rates in the Usual care (UC) and Self-help (SH) groups did not differ at the 6-month (UC 10.5% vs SH 10.9%, P = 0.56) or 15-month follow-up (UC 15.5% vs SH 10.6%, P = 0.17). Among women with an abnormal Pap test result there were no differences by study group in cessation rates at 6-month (UC 9.8% vs SH 11.0%, P = 0.71) or 15-month follow-up (UC 14.6% vs SH 13.4%, P = 0.96). CONCLUSION: Integrating interventions into the clinical setting and involving providers at the point of care may have greater potential for capitalizing on this "teachable moment." Copyright 1999 American Health Foundation and Academic Press. 相似文献
10.
Kangaroo Care with a ventilated preterm infant 总被引:4,自引:0,他引:4