In mice, adriamycin (l7.5mg/kg, ip ) produced heart peroxida-tion abnormality including increased TBA value & decreased gluta-thione peroxidase activity, respectively. But the change of former was not parallel to the latter. The drug also produced early pathological change of the heart i.e. more D-PAS positiveness. The results suggested that the early heart pathological change produced by adriamycin may be related to increased accumulation of pero-xi dative products.

Objective To further confirm the role of lipid-peroxidation caused by oxygen free radicals injury played in the pathogenesis of dilsted cardiomypathy. Methods The superoxide dismutase activities and lipids composi tion of erythrocytes in 18 patients with dilated cardiomyopathy and 16 healthy controls were measured. Results ① Su peroxide dismutase(SOD) activites of erythrocytes were lower in dilated cardiomyopathy(DCM) patients than that in healthy controls (P ＜0. 001). ②The lipids composition of erythrocytes has changed in the DCM patients compared with healthy controls: total lipids changed little (P＞0. 05); total phospholipids were lower, but not significantly (P ＞0.05); total cholesterol increased significantly (P ＜0. 05). The cholesterol to phospholipids molecular ratio of erythrocyte membrane has increased remarkably (P＞0. 05). Conclusion It can be supposed that decreased SOD ac tivities play an important role in the damage of membrane system and the pathogensis of DCM.

The changes of skeletal muscle mitochondral monoamine oxidase (MAO) activity in rats fed with low Se grains from a Keshan-disease area were observed. The rats were killed at the time for feeding 30, 60 and 90 days respectiely. The mitochondrium of skeletal muscle was isolated MAO activity was determined with fluorescent methed. The results showed that in low-Se group the mitochondrial MAO activity was significantly decreased only at the time for 90 days feeding however GSH-px activity in red blood cells and Se content in plasma were significantly decreased at all experimental period as compared to Se-supplemented or stock died group.

The protective effect of selenium (So) on the subacute cardiomyopathy was investigated in the mouse given a single dose of adriamycin (ADR 17. 5mg/kg ip). Se pretreatment (80?g/kg?10 ip) produced protection against the ADR-induced early myocardial damage associated with increased permcability of cell membranes as evidenced by apparent D- PAS (diastase- periodic acid-Schiff) staining material noted in the sarcolemma. The protective effect of Se could be partially explained as the detoxication of lipid peroxides via the action of enhanced cardiac Se-glutathione peroxidase.

Abstract To evaluate the bioavailability of selenium (Se) in Se-yeast to residents with low-Se status, fifty-two youth in a Keshan disease area were randomly divided into three groups, and they were given orally 200 ?g Se daily as So-yeast or sodium selenite, or ordinary yeast for 12 weeks, respectively. Se contents and activities of glutathione peroxidase (GSHpx) in blood were measured at wk 4 and 8 of supplements and 8wk alter the supplements were discontinued. The results show that: 1. the retention of Se in either plasma or erythrocyte is sigificantly higher in Se-yeast than in sodiurn selenite; 2 the effect of Se in Se-yeast is superior to that of sodium selenite for maintaining GSHpx activities; and 3. the relative bioavailabilities of Se in Se-yeast are 556% and 178% when using erythrocyte and plasma Se contents as the response critria, as well as 158% and 116% when estimated by platelet and plasma GSHpx activities. The results indicate that the bioavailability of Se to the residents in a low-Se Keshan disease area is greater when supplemented Se-yeast than selenite.

In the present study the bioavailability of selenium in Se-yeast was compared with that in sodium selenite to rats fed on low-Se diet from a keshan discaes area. The bioavailability of selenium in Se-yeast when estimated by heart, liver kidney and erythrocyte Se contents was significantly greater than that in selenite at wk 2 and 4 of supplement, indicating that selenium in Se-yeast is more cfficiently retained in tissues than selenite selenium. When the criterion used was either platelet or liver glutathione peroxidase (GSH_(?)) activity, the bioavailability was lower for selenium in Se-yeast than for in selenite at wk 2, but higher at wk 4, showing that selenium from both selenite and Se-yeast is clearly available for GSH_(?), synthesis, "although Se-yeast restores GSH_(?) activity more slowly. In addition, the effect of selenium in Se-yeast in maintaining cither Se levels in heart and erythrocyte or GSH_(?) activities in platelets and liver was superior to that of selenite after the selenium supplements were withdrawn.

Sprague—dawey rats were fed for one to three months with Se—deficient grains from Keshan disease area, Se—supplemented diet and stock diet,respectively. Changes of Na~+ ,K~+ ATPase and 5'—nucleotidase activities in cardiac sarcolemma ,Se Contents in liver and plasma and GSH—px activities in Liver and red blood cells of rats were observed. The results showed that Na~+ ,K~+—ATPase. and 5'—nucleotidase activities in cardiac sarcolemma in Se-deficient group rats were significantly decreased,hepatic and plasma Se contents as well as hepatic and erythrocyte GSH—px activities were also significantly decreased at of feeding 30,60 and 90 d as compared to Se—supplemented or stock diet group. There was no significant difference in these parameters between Se—supplemented or stock diet groups There was no significant difference in these paramefers between Se—supplemented and stock diet groups。

In the present study, platelet GSH_(px), SOD activities and cAMP contents, as well as whole blood, erythrocyte, plasma and hair selenium levels were comparatively measured in children from Keshan disease endemic and non-endemic areas. The results showed that blood and hair selenium contents were significantly lower in children of the endemic area than in those of the non-endemic area; children in the endemic area had a signifi cantly lower platelet GSH_(px) activities as compared to those in the non-endemic area, but no remarkable difference of platelet SOD activities and cAMP contents between children in the two areas was observed. The results indicate that the reduced GSH_(px) activity of low-selenium children in the endemic area may result in alterations in platelet functions and arachidonic acid metabolism.

Objective To study the difference of image quality and radiation dose between different exposure modes with full-field digital mammography (FFDM).Methods The Fluke18-220mammographic phantom was exposed by FFDM system with different exposure modes at automatic exposure control ( AEC ) ,including contrast mode,standard mode and dose mode,and the exposure factors and radiation dose were recorded.The images on monitor with the best window width and window level were read by four independent radiologists.The images of specks groups,nylon fibers and masses was assessed by the four experienced readers at the criterion of American College of Radiology.Results The detection of specks groups,nylon fibers and masses were statistically different at the contrast mode and standard mode (F =41.321,P ＜ 0.05),further at the contrast mode and dose mode.The detection of specks groups、nylon fibers and masses were not statistically different( P ＞ 0.05 ) at standard mode and dose mode,but the radiation doses were different.The ESD at standard mode and dose mode was 4.5 and 3.15 mGy,respectively.The AGD of standard mode and dose mode was 1.18 mGy and 0.78 mGy,respectively.Conclusions The standard mode and dose mode of FFDM might be fit for most patients,especially at the dose mode.Contrast mode of FFDM should be strictly controled in use.

A three-phase depletion/repletion/depletion feeding study was designed to investigate the changes of Se levels and glutathione peroxidase (GSH-Px) activities in tissues and blood in rats fed for 6 weeks low-Se diet (6 ppb Se) from a Keshan disease area during the supplementations of Se as Ziyang high-Se wheat (1.175 ppm Se) or sodium selenite (dietary Se 219 and 223 ppb respectively) and after the supplements were discontinued, and to evaluate the relative bioavailability of Se in the wheat. The resalts showed that the average bioavailability of Se in high-Se wheat derived from the values at wk 2, 4 and 6 of supplement was close to that in selenite when plasma, erythrocyte, kidney, liver and cardiac Se contents were used as the response criteria, the relative bioavailabilities being 98%, 104%,100%,96% and 101% (sodium selenite = 100%) respectively. The bioavailability was lower for Se in high-Se wheat (70% or 90%) than for selenite when estimated by erythro-cyte or cardiac GSH-Px activities. However, the bioavailabilities of high-Se wheat Se in various tissues were not all the same at different stages of supplement. In addition, the effect of Se in high-Se wheat in maintaining either Se levels in heart, liver and erythrocyte or GSH-Px activity in heart was superior to that of selenite 3 weeks after the Se supplements were withdrawn.