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This study investigates the contribution of body fat stores on the age-associated increase in serum cholesterol and triglyceride levels. Percentage of body fat was measured by hydrostatic weighing, and serum cholesterol, triglyceride, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol levels were determined in a sample of 472 healthy men and women ages 18-50 years. In both sexes, body fat mass was significantly correlated with serum cholesterol (r = 0.21 in men and r = 0.24 in women, P less than 0.01) and triglyceride (r = 0.33 in men and r = 0.24 in women, P less than 0.01) levels. After adjustment for the association between age and serum cholesterol, no correlation was observed between body fat mass and serum cholesterol (r = 0.01 in men and r = 0.09 in women). After correction for age, serum triglyceride levels remained significantly correlated with body fat mass (r = 0.26 and r = 0.17 in men and women, respectively, P less than 0.05). As body fat also increases with age, the possibility that a partial correlation coefficient procedure eliminated a portion of the age effect mediated by an age-related increase in fat, was addressed by performing further analyses. Within each sex subsample two sets of analyses were performed on (a) three groups of subjects individually paired for age but with different levels of body fat stores, and (b) three groups of subjects paired for the amount of body fat but differing in age.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
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Erythropoietin and oxidative stress in haemodialysis: beneficial effects of vitamin E supplementation 总被引:10,自引:7,他引:3
Cristol J; Bosc J; Badiou S; Leblanc M; Lorrho R; Descomps B; Canaud B 《Nephrology, dialysis, transplantation》1997,12(11):2312-2317
Oxidative stress can produce profound alterations to cellular membrane
lipids, impairing cell metabolism and viability. This phenomenon,
previously observed in haemodialysis patients, had been proposed as a
significant factor in regard to haemodialysis-related shortened red blood
cells (RBC) survival. In the present study, several parameters associated
with oxidative stress were evaluated in a group of haemodialysis patients
either receiving erythropoietin therapy (n=12, mean erythropoietin dose
88±24 U/kg/week) or not receiving such therapy (n=20), and in 38
controls. Malonyldialdehyde (MDA, nmol/ml), an end-product of lipid
peroxidation, and RBC anti-oxidant systems were measured, including RBC
&agr;-tocopherol (RBC vitamin E, mg/l), RBC glutathione (GSH,
nmol/mgHb), and RBC superoxide dismutase activity (SOD, U/mgHb). Plasma
vitamin E concentrations were also evaluated. Finally, oral vitamin E
supplementation (500 mg daily), an exogenous antioxidant, was administered
for 6 months to seven patients from the dialysis group receiving
erythropoietin while oxidative parameters were repeatedly evaluated and
erythropoietin requirements monitored, in order to appreciate the
therapeutic relevance of an antioxidant supplementation. An elevation of
serum MDA was observed in all haemodialysis patients and a significant
decrease in RBC vitamin E, despite normal serum vitamin E levels.
Furthermore, the reduction in RBC vitamin E was more important in patients
treated with erythropoietin. Vitamin E supplementation resulted in a
significant increase in RBC vitamin E (from 0.3±0.1 to
1.2±0.2 mg/l of pellet) and a reduction in erythropoietin dose
(from 93±24 to 74±26 U/kg/week) while maintaining
stable haemoglobin concentrations. These results suggest that the oxidative
stress could be one of the resistance factors to erythropoietin response in
haemodialysis and that vitamin E supplementation could have a sparing
effect on erythropoietin dosage requirement. Key
words: antioxidant; erythropoietin; haemodiafiltration; lipid
peroxidation; oxidative stress; vitamin E
相似文献
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The acute effect of food intake on the activity of the sympathetic nervous system (SNS) in both heart and brown adipose tissue (BAT) was investigated in mice. Upon delivery to the laboratory mice were housed singly and divided into two groups. Half the mice were accustomed to eat their daily food ration in two meals whereas the other half were given continuous access to food. SNS activity in both heart and BAT was estimated by measuring the accumulation of dopamine (DA) after having blocked the transformation of dopamine into noradrenaline (NA) with 1-cyclohexyl-2-mercapto-imidazole (CHMI). CHMI inhibits the enzyme dopamine beta-hydroxylase. On the day SNS activity was assessed, continuously fed (CF) or meal-fed (MF) mice were injected with either saline or CHMI one hour before being killed. In order to assess the anticipatory effects of being fed, a group of mice already accustomed to the meal-feeding schedule were not allowed to eat after the injections. Additional CF and MF mice were killed without being injected in order to determine the basal levels of both DA and NA. The results show that the accumulation of DA in both heart and BAT was higher in MF than CF mice regardless of whether MF mice were or were not fed after the injection of CHMI. It therefore appears that the intake of food may increase SNS activity in various tissues in mice, and that such a response may be largely of cephalic origin. 相似文献
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A framework for evaluating image segmentation algorithms. 总被引:4,自引:0,他引:4
Jayaram K Udupa Vicki R Leblanc Ying Zhuge Celina Imielinska Hilary Schmidt Leanne M Currie Bruce E Hirsch James Woodburn 《Computerized medical imaging and graphics》2006,30(2):75-87
The purpose of this paper is to describe a framework for evaluating image segmentation algorithms. Image segmentation consists of object recognition and delineation. For evaluating segmentation methods, three factors-precision (reliability), accuracy (validity), and efficiency (viability)-need to be considered for both recognition and delineation. To assess precision, we need to choose a figure of merit, repeat segmentation considering all sources of variation, and determine variations in figure of merit via statistical analysis. It is impossible usually to establish true segmentation. Hence, to assess accuracy, we need to choose a surrogate of true segmentation and proceed as for precision. In determining accuracy, it may be important to consider different 'landmark' areas of the structure to be segmented depending on the application. To assess efficiency, both the computational and the user time required for algorithm training and for algorithm execution should be measured and analyzed. Precision, accuracy, and efficiency factors have an influence on one another. It is difficult to improve one factor without affecting others. Segmentation methods must be compared based on all three factors, as illustrated in an example wherein two methods are compared in a particular application domain. The weight given to each factor depends on application. 相似文献
8.
Brandon JC; Teplick SK; Haskin PH; Sammon JK; Muhr WF; Hofmann AF; Gambescia RA; Zitomer N 《Radiology》1988,166(3):665-667
The authors describe their experience with methyl tertiary butyl ether (MTBE) in a larger series of patients than previously reported in order to acquaint physicians with both its effectiveness for dissolution of common bile duct calculi and the limitations of its use. Ten patients with 13 biliary calculi underwent percutaneous stone dissolution treatment with the experimental cholesterol solvent, MTBE. Three stones completely dissolved within 30 minutes, seven were reduced in size, and three were visibly unaffected. All stones not completely dissolved were easily extracted by means of a stone basket except for one in a patient taken to surgery. Although MTBE perfusion is an effective technique for management of biliary calculi, practitioners should be aware that its use is quite time consuming and its odor difficult to control. 相似文献
9.
Limited-field-of-view radio-frequency receiver antennas provide improved near-field sensitivity for magnetic resonance imaging by decreasing the antenna volume. The Helmholtz-type surface coil, consisting of two flat rings, is an organ-encompassing antenna that takes advantage of this principle to yield an improved signal-to-noise ratio (S/N). The coil was tested in a group of 50 patients and 16 healthy volunteers. Images obtained with the Helmholtz coil demonstrated quantitatively superior S/N of 2.2-fold or greater than that of comparison body coil images, as well as qualitatively superior anatomic resolution. 相似文献
10.
B Bader-Meunier E Haddad P Niaudet C Loirat T Leblanc Z Amoura C Bodemer P Cochat G Deschênes I Koné-Paut M Lévy A M Prieur P Quartier B Ranchin R Salomon J C Piette 《Archives de pédiatrie》2004,11(8):941-944
Childhood-onset systemic lupus erythematosus (SLE) is often severe and has a serious long-term morbidity. Pediatric guidelines about its management do not exist. The French study group of childhood-onset SLE proposes recommendations about the investigation which are needed at diagnosis and during follow-up of SLE, in order to adjust the treatment according to the severity of the disease and to avoid unnecessary investigations. 相似文献