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I Djujić

Publications and source records attributed to I Djujić.

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Selenium research in Serbia, Yugoslavia.

Data on selenium (Se) deficiency in Serbia are presented following 10 years of research. We studied the Se content in ores, stream sediment, soil, cereal crops, and garlic grown in these soils, food, and human serum and hair from 55 communities. Most of the results indicated a serious Se deficiency. In some communities, the Se content of grain, garlic, and human serum and hair approached that of the low-Se belt in China. We assume that an extremely low Se level in the human population could be a risk factor for the development of Balkan nephropathy (BN) and for the very high incidence of urinary tract tumors (UTT) in endemic areas, as well as high mortality rates of malignant diseases. On the other hand, some regions with relatively higher serum Se levels had significantly lower mortality rates of cancer and cardiovascular diseases.

Diet↗

Variation of selenium content in growing wild plants during vegetative period.

There is evidence that selenium (Se) is essential for humans, animals, and some species of microorganisms. This study examines the dynamics of the change of Se accumulation in some growing wild plants: Astragalus onobrychis var. Chlorocarpus (Gris.) Stoj. et Stef. (Leguminosae), Oxytropis pilosa (L.) DC., Salvia officinalis, L., and Simphytum ottomanum L. The influences of some ecological factors (Se content in soil, temperature, and rainfall) have also been surveyed. The Se content of plants from Serbia was 44.5 to 177.0 microg/kg of dry weight. Astragalus onobrychis var. Chlorocarpus (Gris.) Stoj. et Stef. (Leguminosae) accumulates the highest Se content in the blooming stage (161.3 microg/kg). All soils studied were deficient in selenium (< 250 microg/kg). We found a significant correlation between Se content in plants and in the soil (p = 0.88). Rainfall has an influence on Se content in Oxytropis, Salvia, and Simphytum, but not in Astragalus. Our results suggest that Se cannot have a similar role in all plants examined.

Environment↗

Selenium intake as a modulator of responsiveness to oxidative stress.

A deficiency in important components of the endogenous antioxidative defense system (AODS) against the production of reactive oxygen species, including free radicals, results in the accumulation of oxidative damage, inducing oxidative stress. A dietary deficiency in selenium (Se), an important part of AODS, can increase the sensitivity of a living system to oxidative stress. We investigated the effects of Se supplementation, in the form of Se-enriched yeast, on the AODS resistance of red blood cells (RBC) to experimentally induced oxidative stress. We analyzed the alterations in main components of the AODS, such as the amount of reduced (GSH) oxidized glutathione (GSSG), Se-dependent glutathione peroxidase (GSH-Px), Se content, catalase (CAT), and thiobarbituric acid reactive substances (TBARS), in RBC of male Wistar rats exposed to gamma rays and supplemented with Se-enriched yeast (SeY) in drinking water. The results suggested that the increased Se level generally exhibited a protective effect against whole body irradiation, reducing the expenditure of the AODS components in defense. These reductions differed depending on the time observed and the parameter investigated but, generally, SeY supplementation induced a faster restoration of the AODS after this kind of oxidative stress.

Animals↗

Effect of X-rays on selenium content in rat jaws.

It is known that X-radiation of the growing jaws results in impaired dental development. We investigated the role of selenium (Se) in radiation-induced dental growth retardation. The heads of 8-day-old female rats were irradiated with a single dose of 9.6 Gy of X-rays. Another group of animals was irradiated under the same conditions but, for radioprotective purposes, were also in deep hypothermia during radiation exposure. Nonirradiated animals served as controls. The Se content in the upper and lower jaws was analyzed by hydride generation atomic absorption spectrophotometry. In the upper jaws of the animals exposed to irradiation, the Se concentration was significantly lower than in those irradiated under conditions of hypothermia (p < 0.05), although both groups showed no significant difference in Se concentration when compared to nonirradiated controls. In the lower jaws, the concentration of Se was significantly reduced in the irradiated group when compared with controls and the rats irradiated under conditions of hypothermia (p < 0.05). There was no significant difference in Se concentration between rats irradiated under conditions of hypothermia and nonirradiated controls. There was no significant change in Se concentration in the jaws of the rats protected by hypothermia during radiation exposure compared with nonirradiated controls. Although Se loss in the irradiated bone could be prevented by hypothermia, we could not prove that Se loss per se is the cause of growth retardation nor that its retention has a radioprotective effect.

Analysis of Variance↗

Effects of cereal supplementation with selenium.

Selenium (Se) is an essential nutrient. Surveys of Se status showed that Serbia is a low Se area. To increase the Se concentration, we supplemented Se to domestic animals and humans. The latest results showed that increasing Se content in domestic animals and humans induces a small increase in mean Se level. Exceptions were residents of urban, economically developed communities in which an increase in Se level were significant. The soil-plant system is the main natural source of Se for animals and humans. We used field treatments to raise the Se level in plants to the desired level. Foliar application of Se as Na2SeO3 was tested on cereals growing on different soil types. The influence of different growth factors on the uptake and distribution of Se in plants was tested and discussed. The foliar application of 6 g Se/ha is sufficient to raise the native Se content in whole wheat to levels of 42 to 67 microg/kg and in corn to levels of 19 to 36 microg/kg. The application of 12 g Se/ha is sufficient to raise Se levels in wheat to 65 to 180 microg/kg and in corn to 31 to 46 microg/kg.

Agriculture↗

Selenium deficiency in Serbia and possible effects on health.

Ten years study of selenium status in stream sediments, rocks, soils, water, cereal crops and food, as well as in the human tissues, has shown a Se deficiency in most parts of this country. Some of the results are presented and discussed, especially in connection with etiology of Balkan nephropathy and high incidence of urinary tract tumors in endemic areas.

Deficiency Diseases↗

Selenium deficiency in Yugoslavia.

Data on selenium (Se) deficiency in Yugoslavia are presented. The results include Se content of soil, cereal crops, and garlic grown in these soils, and human serum and scalp hair from several towns and regions. All data indicate a serious Se deficiency: soil (n = 140), the mean value of 200 +/- 69.6 micrograms/kg Se; wheat, (58) mean = 20.5 +/- 12.4 micrograms/kg; corn, (79) mean = 13.7 +/- 13.6 micrograms/kg; and garlic, (66) mean = 13.7 +/- 17.1 micrograms/kg Se. Analyses of human tissue show a very low Se status of the Yugoslav population: serum, (n = 875) mean = 50.0 +/- 18.0 micrograms/L and scalp hair, (388) mean = 94 +/- 16 micrograms/kg Se. In some regions, Se contents of grain, garlic, and human serum and hair are approaching those in the low-Se belt in China. It is assumed that very low Se status of a human population could be a risk factor in the development of Balkan Endemic Nephropathy (BEN) and in a high incidence of urinary tract tumors (UTT) in endemic areas.

Balkan Nephropathy↗