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Jan A. E. Stenson Mats O. G. Eriksson 《Archives of environmental contamination and toxicology》1989,18(1-2):201-206
We describe some mechanisms behind the biotic changes in acidified lakes in Scandinavia. Besides direct effects, such as reduced reproduction or survival of fish and invertebrates due to low pH or exposure to toxic metals, we emphasize the importance of indirect effects. Mechanisms involved are of an ecological character; such as a shift of top predatores from fish to invertebrates and a reduced decomposition rate due to decreased abundance of detrivores, as well as feed-back effects on the abiotic environment; such as reduced productivity and turnover rate of nutrients and an increase in water transparency. We include the aspects of how bird species in aquatic habitats may be indirectly affected. 相似文献
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Mewissen MW; Erickson SJ; Foley WD; Lipchik EO; Olson DL; McCann KM; Schreiber ER 《Radiology》1989,173(1):155-157
Color Doppler flow imaging or compression ultrasound (US) was used to prospectively determine frequency of thrombosis at 54 venous insertion sites (47 in common femoral veins, seven in right internal jugular veins) after percutaneous placement of Greenfield filters for interruption of the inferior vena cava. Fifty-one filters were successfully placed in 51 patients with a dilator set or a balloon angioplasty catheter. Nine focal thrombi were detected in the common femoral vein (19%) and one in the right internal jugular vein (14%). Use of dilators induced eight thrombi (24%), compared with two (10%) from balloon catheters. The left common femoral vein had a high frequency of thrombosis, regardless of dilation technique (five of nine). Of nine patients with acute common femoral vein thrombosis, four became symptomatic within 10 days after the procedure. Patients may remain asymptomatic or have delayed symptoms; thus, US is valuable for determining patients at risk of thrombosis of the common femoral vein. 相似文献
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B Stenson L Syhakhang C S Lundborg B Eriksson G Tomson 《International journal of technology assessment in health care》2001,17(4):579-589
OBJECTIVES: The objective of this study was to assess the effectiveness of government regulation of private pharmacy practice in a low-income country. METHODS: The intervention comprised inspections of the pharmacies, information, and distribution of documents to drug sellers and sanctions. It was implemented at two different intensity levels, active and regular intervention. The methods used to assess the effect of the interventions were interviews with the district drug inspectors, drug sellers and customers, inspection of drug purchases, and indicator surveys of pharmacies. Indicators for pharmacy-specific quality as well as for dispensing quality were developed. RESULTS: The main finding was one of strong overall improvements from initially low levels. The improvements were particularly marked by increases in the availability of essential materials for dispensing by 34% and in order in the pharmacy by 19%. Information given to customers increased from 35% to 51% and the mixing of different drugs in the same package went down from 17% to 9%. The pharmacies in the active intervention districts showed greater improvements for four of the six indicators, although statistically significant compared with the regular intervention districts only for the essential materials indicator. CONCLUSIONS: It was concluded that the regulatory activities have probably been an important factor behind the service quality improvements. It appeared feasible as well as effective to regulate private pharmacy practice in this particular low-income setting. 相似文献
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Maggie KM Ma Helen KW Law Kin Sun Tse Kwok Wah Chan Gary CW Chan Desmond YH Yap Maggie MY Mok Lorraine PY Kwan Sydney CW Tang Bo Ying Choy Tak Mao Chan 《International journal of urology》2018,25(5):450-455
Objectives
To evaluate the use of shear wave elastography in assessment of kidney allograft tubulointerstitial fibrosis.Methods
Shear wave elastography assessment was carried out by two independent operators in kidney transplant recipients who underwent allograft biopsy for clinical indications (i.e. rising creatinine >15% or proteinuria >1 g/day). Allograft biopsies were interpreted by the same pathologist according to the 2013 Banff Classification.Results
A total of 40 elastography scans were carried out (median creatinine 172.5 μmol/L [interquartile range 133.8–281.8 μmol/L]). Median tissue stiffness at the cortex (22.6 kPa [interquartile range 18.8–25.7 kPa] vs 22.3 kPa [interquartile range 19.0–26.5 kPa], P = 0.70) and medulla (15.0 kPa [interquartile range 13.7–18.0 kPa] vs 15.6 kPa [interquartile range 14.4–18.2 kPa]) showed no significant differences between the two observers. Interobserver agreement was satisfactory (intraclass correlation coefficient of the cortex 0.84, 95% CI 0.70–0.92 and intraclass correlation coefficient of the medulla 0.88, 95% CI 0.78–0.94). The areas under the receiver operating characteristic curves for detection of tubulointerstitial fibrosis were estimated to be 0.75 (95% CI 0.61–0.89), 0.85 (95% CI 0.75–0.95) and 0.65 (95% CI 0.53–0.78) for cortical, medullary tissue stiffness and serum creatinine, respectively.Conclusions
Shear wave elastography can be used as a non‐invasive tool to evaluate kidney allograft fibrosis with reasonable interobserver agreement and superior test performance to serum creatinine in detecting early tubulointerstitial fibrosis. 相似文献67.
Metabolism of arachidonic acid in ionophore-stimulated neutrophils. Esterification of a hydroxylated metabolite into phospholipids. 总被引:5,自引:0,他引:5 下载免费PDF全文
[14C]Arachidonic acid incubated with human neutrophils was esterified into phospholipids and triglycerides. Stimulation of these labeled neutrophils with ionophore A23187 (2 microM) results in release of [14C]arachidonate from phospholipid and its metabolism to prostaglandin E2 and 5-hydroxy-6,8,11,14-eicosatetraenoic acid (5-HETE), a lipoxygenase product. The released arachidonate is also metabolized to a polar lipid of unknown composition here disignated compound A. 5-HETE was found to be released into the medium and then taken up again by the cells. To determine its metabolic fate, [14C]5-HETE was prepared biosynthetically, purified, and incubated with stimulated, unlabeled neutrophils. Most of the radioactivity entered the cells and was esterified into phospholipids and triglycerides. The radiolabeled complex lipids were saponified, and the released fatty acids cochromatographed with authentic 5-HETE. The esterification of 5-HETE, a hydroxylated fatty acid, into membrane phospholipids may be an example of a more generalized mechanism for altering membrane characteristics. 相似文献
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