Selenium status of industrial worker

The purpose of this study was to assess the selenium status of a well-defined industrially employed population: eighty-six oil refinery workers. Plasma selenium levels and erythrocyte GSH-Px activities were significantly lower in this industrial group (86 subjects) than in non-industrial group (174 subjects). In order to evaluate whether these lower values were responsive to supplementation, ten subjects from the industrial group were further studied for 12 weeks. Five of these subjects consumed a selenium supplement, 50 μg Se as sodium selenite, once a day for eight weeks (weeks 2 to 10 of study). Diet histories revealed that these 10 workers consumed an average of 217±73 μg Se/day indicating that they were consuming selenium levels above the recommendations of the Food and Nutrition Board of the NRC. The supplemented group had significantly higher whole blood selenium levels and GSH-Px activity than the non-supplemented group and this difference was due to a drop in the levels found in the non-supplemented group at weeks 8 and 10. These data suggest that selenium supplementation prevented the decreases in blood selenium levels and GSH-Px activity experienced by the non-supplemented subjects. Also, there was a positive correlation between blood selenium levels and GSH-Px (r=0.45, p<0.001). Thus, these oil refinery workers maintained GSH-Px activity only when consuming a selenium supplement suggesting that these workers may have a higher selenium need than any previously studied populations.     

Retrograde tracing of the subset of afferent connections in mouse barrel cortex provided by zincergic neurons

Lateralization of brain functions is a widespread phenomenon in vertebrates. With the well-known lateralization in the processing of human speech and the parallels that exist between birdsong and language, songbirds are interesting for addressing such questions. In the present study, we investigated the central processing of communicative and artificial sounds in starlings, in an integrative part of the song system: the HVC. Neuronal responses to acoustic stimuli were systematically recorded in both hemispheres while the birds were awake, and then anesthetized, allowing quantitative comparisons of the responses obtained in each situation. The total proportion of responsive sites in the HVC of the left and right hemispheres of all birds revealed a significant predominance of the HVC of the right hemisphere when the birds were awake, whereas a high interindividual variability appeared when the birds were anesthetized. When neuronal responses as a whole were further examined, the responses to each type of stimulus appeared to be nonrandomly distributed over the different situations, and some specialization may appear. The results suggest a complex and state-dependent hemispheric specialization toward behaviorally relevant classes of stimuli. In awake birds, the HVC of the left hemisphere may be more involved in the processing of songs that are used in individual recognition at distance, whereas the HVC of the right hemisphere may deal with long and complex sequences of a song that is involved in short-distance communication, especially between males and females. With birds under anesthesia, this pattern is strongly modified.     

Selenium diet-supplementation improves cocaine-induced myocardial oxidative stress and prevents cardiac dysfunction in rats

Chronic cocaine abuse causes cardiac dysfunction and induces oxidative stress. The goal of this study was to evaluate whether an enhanced antioxidant pool, induced by the administration of selenium, may prevent the myocardial dysfunction induced by cocaine. Cocaine was administered for 7 days (15 mg/kg/day, i.p.) to rats pretreated for 4 weeks with selenium (1.16 mg/L/day, p.o.). Cardiac function was evaluated by cardiac index and left ventricular (LV) fractional shortening (FS) measured by echocardiography. The redox ratio and enzymatic activities of glutathione peroxidase (GPX) and superoxide dismutase (SOD) were measured in the LV myocardium. Cocaine administration induced a cardiac dysfunction, as evidenced by a decrease in cardiac index and LV FS as well as by an increase in LV diameters. Moreover, antioxidant markers and redox ratio were altered in rats after cocaine exposure. Selenite supplementation induced a significant limitation of cardiac index and FS alterations observed after cocaine administration. This improvement in cardiac function was associated with a redox ratio recovery while SOD and GPX activities remained unchanged. Thus, selenite reversed both the oxidative stress and the contractile dysfunction induced by cocaine administration. These results suggest a major role of oxidative stress in the cocaine-induced cardiotoxicity.     

Status of selenium in prostate cancer prevention

The complete, 13 years, results of the Nutritional Prevention of Cancer Trial have been analysed, causing some speculation over the robustness of the previously reported findings of reduction of cancer risks by supplements of selenium (Se) to a cohort of older Americans. These analyses confirmed that Se supplementation was associated with marked reductions in risks to total (all-site except skin) carcinomas and to cancers of the prostate and colon-rectum. Of those deep-site treatment effects, the most robust was for prostate cancer, which was more frequent, and was confirmed by serum prostate-specific antigen level. Recent subgroup analyses showed Se supplementation reduced risk of cancer mostly among subjects who entered the trial with plasma Se levels in the bottom tertile of the cohort. Other recent findings have demonstrated that Se treatment can promote apoptosis in prostate cancer cells and, possibly, impair their proliferation through antiangiogenic effects. Thus, a body of basic understanding is developing by which one can understand and evaluate the results of the Nutritional Prevention of Cancer and future clinical trials. This understanding also requires inclusion of the mechanisms of Se transport and cellular uptake, so that appropriate inferences can be made from findings from cell culture systems, which tended to use effective Se doses much larger than relevant to cells in vivo. Also needed is information on the chemical speciation of Se in foods, so that Se delivery can be achieved in ways that are effective in reducing cancer risk and is also safe, accessible and sustainable.     

Selenium status, kwashiorkor and congestive heart failure

Selenium deficiency is associated with congestive heart failure (CHF) in geographic areas where dietary selenium intake is low and in individuals receiving total parenteral nutrition. Among 66 children with kwashiorkor (including marasmic-kwashiorkor), those who developed CHF had lower serum selenium concentrations than those who did not (32.9 +/- 8.3 vs 41.1 +/- 11.9 microg/L, mean +/- SD, p = 0.03). This association was independent of serum albumin and selenium status was not associated with severity of symptoms, anthropometric indices or HIV infection. CONCLUSION: This association raises the possibility that selenium may contribute to CHF in washiorkor.     

微量元素硒与自由基

硒是基于抗氧化酶的必需组分,它通过消除脂质氢过氧化物,阻断活性氧和自由基的致病作用,而起到防病作用,因此机体硒水平的高低直接影响了机体抗氧化能力,以及对相关疾病的抵抗能力。     

Correlation between hair selenium concentration and gastric cancer

Objective: To investigate the correlation between hair selenium (Se) level and gastric cancer. Methods: Atomic fluorescence spectrophotometer(AFS) was used to detect the Se level in hair. Results: The Se concentration in patients with gastric cancer ranged from 0.25 to 2.33μg/g(0.825±0.51μg/g), and that of health individuals ranged from 4.23 to 9.21μg/g(6.29±1.68μg/g). The results showed that the Se concentration in the patients' hair was significantly lower than that in controls (P＜0.01).Conclusion: There is a correlation between hair concentration and gastric cancer.     

SELENIUM AND VITAMIN E IN CORD BLOOD FROM PRETERM AND FULL TERM INFANTS

ABSTRACT. Selenium was determined in erythrocytes and serum, and vitamin E and β-lipoprotein in serum from cord blood samples of 31 full term and 20 preterm infants. Venous samples from 21 mothers at birth and 15 normal adult women were also analyzed. No difference for either selenium or vitamin E was found between the preterm and full term infants. The selenium concentration in red blood cells was the same for newborn, mothers at birth, and normal adult women. The serum concentration of selenium was, however, significantly lower in the newborn, the mean level in the children being 64% of that in the mothers. The level in the mothers did not differ from that in non-pregnant women. The vitamin E concentration was found to correlate very well with the β-lipoprotein concentration. This indicates that differences in the transport capacity account for the large difference in the serum tocopherol levels of mothers at birth and newborn.     

云锡工人硒摄入量与代谢研究

对云南锡矿矿工、坑上作业工人及矿区农民硒的摄入量、代谢、血硒与含硒的谷胱甘肽过氧化物酶活性的研究发现,云锡所在地为低硒区。不同人群中,以肺癌患者及高风险人群血硒较低.     

Potentially Life-Threatening Cardiac Dysrhythmia in a Child with Selenium Deficiency and Phenylketonuria

ABSTRACT. Selenium deficiency is a frequent finding in children with phenylketonuria (PKU) receiving dietary treatment. We report the occurrence of episodic ventricular tachycardia in a 9-month-old infant with PKU. Serum selenium (Se), 0.13 μmol/1 (normal range 0.28–1.12 μmol/1, mean ± 2 SD), and whole blood glutathione peroxidase (GSHPX), 16 U/g Hb (normal range 19.5–34.3 U/g Hb, mean ± 2 SD), were low. Auscultation of cardiac rhythm is recommended during the routine follow-up of young children with PKU. Se deficiency should be considered in the aetiology of a dysrhythmia and corrected with Se supplementation.