- MeSH
- Cardiovascular Diseases chemistry metabolism MeSH
- Neoplasms metabolism prevention & control MeSH
- Selenium analysis metabolism MeSH
- Trace Elements MeSH
- Publication type
- Review MeSH
Selen je pro živočišný organismus nezbytný stopový prvek, který je biologicky aktivní jako selenocystein v aktivním centru enzymů. Inkorporace probíhá na základě genetické exprese a selen je tedy jediný stopový prvek s genetickou kontrolou. Současně lze konstatovat, že selenocystein je 21. aminokyselinou. Pro každou živočišnou buňku jsou nezbytné alespoň dva selenoenzymy, a to ze skupiny GSH-peroxidáz a dejodáz. První brání buňku i celý organismus před oxidačním poškozením a z toho pramenícími nemocemi a poruchami, jako jsou bakteriální a virové nákazy, svalové dystrofie, artropatie, tvorba arteriálních plátů či malignity a další. GSH-Px má celou řadu dalších regulačních funkcí, jako regulaci tvorby prostaglandinů, prostacyklinů, leukotrienů a tromboxanů. Dejodázy zajišťují regulaci buňky tvorbou a rozkladem biologicky aktivního hormonu trijodtyroninu. Selenoproteiny inaktivují některé kancerogenní organické látky a rovněž vyvazují jedovaté těžké kovy. Ve specializovaných buňkách byly zjištěny ještě další tkáňově specifické selenoproteiny, zatím ještě s neobjasněnou funkcí. Stav a příjem selenu v organismu, na kterém je závislá tvorba selenoproteinů přímo i nepřímo, se určují několika parametry, z nichž nejpoužívanější jsou obsah selenu v séru a moči. Na základě měření těchto parametrů v šesti regionech ČR lze předběžně konstatovat silný nedostatek tohoto esenciálního stopového prvku u běžného obyvatelstva a podle předběžných nálezů je pro skupiny více deficitem ohrožené (rostoucí děti, těhotné a kojící ženy, staří lidé) situace ještě horší.
Selenium is an essential trace element for animals. It is biologically active as selenocysteine in the active centre of selenoproteins with enzymatic functions. Incorporation of selenocysteine occurs on the basis of genetic expression and selenium is the only trace element under direct genetic control. Selenocysteine can be considered the 21st amino acid with regard to its biosynthesis and incorporation into proteins. At least two types of selenoproteins are necessary for each animal cell, the first from the family of GSH-peroxidases and the second from the family of deiodinases. GSH-peroxidases are the most powerful antioxidant enzymes, which defend the cell and whole organism against oxidative damage and thus from oxidative diseases and disorders such as cardiovascular diseases, malignancies, bacterial or viral diseases, muscle dystrophy, arthropathy, arterial plaques, and others. GSH-Px have many other regulatory functions such as regulation of biosynthesis of prostaglandins, prostacycline, leukotrienes, and thrombo- xans. Deiodinases regulate the metabolism of biologically active triiodothyronine and thus thyroid hormone regulation of the whole organism. Selenoproteins act against cancerogenic effects of some organic molecules and bind heavy metals. Tissue-specific selenoproteins without a known biological function have been detectes in some specialised tissues with a high priority for selenium. One of the regulators of selenoprotein synthesis is the selenium status of the organism. Its state and intake may be assessed by analyses of selenium indexes. The most often used indexes are serum selenium and urinary selenium. On the basis of its analyses in six regions of the Czech Republic, severe selenium deficiency has been found in inhabitants of this country, which is even profound for more distressed groups like growing children, pregnant and lactating women, and the elderly.
- MeSH
- Peroxidases MeSH
- Selenium blood metabolism urine MeSH
- Selenocysteine physiology deficiency MeSH
- Publication type
- Review MeSH
Selenium is a trace element that is essential for living organism. Its beneficial effect is, however, expressed in a very narrow dosage range: the high and low doses of selenium are connected with pathological manifestations. The toxicity depends on the chemical form of selenium, state of organism, interactions with heavy metals and on the stage of ontogenetic development. Whereas one dose of sodium selenite (20 micromol/kg b.w.) is lethal in adult rats, suckling rats are entirely resistant. However, within one week after administration of the same dose, cataract of eye lens developed. The highest incidence of cataract was observed in 10-day-old animals and it decreased until day 20. From postnatal day 20 to day 40 the rats were resistant to both the lethal and cataractogenic effects of selenium. The incidence of cataract may be suppressed by premature weaning, lower hydration of suckling, change of water soluble/water insoluble lens protein ratio, thyroxine treatment, and by interaction with mercury. By means of its oxidative and reduction properties, selenium is involved in the maintenance of the cell redox homeostasis. Typical example is its possible cardioprotective effect: selenium decreased number of arrhythmias, reduced infarct size and improved the contractile recovery after ischemia/reperfusion injury. Selenium supplementation may thus increase cardiac tolerance to ischemic damage.
- MeSH
- Myocardial Infarction pathology prevention & control MeSH
- Cardiotonic Agents pharmacology therapeutic use MeSH
- Cataract metabolism pathology MeSH
- Humans MeSH
- Lens, Crystalline drug effects pathology MeSH
- Oxidation-Reduction MeSH
- Myocardial Reperfusion Injury physiopathology prevention & control MeSH
- Selenium Compounds pharmacology toxicity MeSH
- Arrhythmias, Cardiac pathology prevention & control MeSH
- Age Factors MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Review MeSH
Selenium is an essential trace element important for many physiological processes, especially for the functions of immune and reproductive systems, metabolism of thyroid hormones, as well as antioxidant defense. Selenium deficiency is usually manifested by an increased incidence of retention of placenta, metritis, mastitis, aborts, lowering fertility and increased susceptibility to infections. In calves, lambs and kids, the selenium deficiency demonstrates by WMD (white muscle disease), in foals and donkey foals, it is associated with incidence of WMD and yellow fat disease, and in pigs it causes VESD (vitamin E/selenium deficiency) syndrome. The prevention of these health disorders can be achieved by an adequate selenium supplementation to the diet. The review summarizes the survey of knowledge on selenium, its biological significance in the organism, the impact of its deficiency in mammalian livestock (comparison of ruminants vs. non-ruminants, herbivore vs. omnivore) and possibilities of its peroral administration. The databases employed were as follows: Web of Science, PubMed, MEDLINE and Google Scholar.
- MeSH
- Humans MeSH
- Dietary Supplements MeSH
- Mammals metabolism MeSH
- Selenium deficiency metabolism physiology MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
Selen je esenciální stopový prvek, jehož nedostatek je spojován s četnými závažnými onemocněními včetně onkologických a diabetes mellitus. Příjem selenu byl sledován ve stravě onkologických pacientů a pacientů s diabetickou dietou v rozsahu deseti dnů letního období a deseti dnů zimního období. V analyzovaném období byla všechna jídla sestavena ze 111 potravin. Hlavními zdroji selenu u obou diet byly potravinové skupiny maso a masné výrobky, cereálie, mléko a mléčné výrobky, které dotovaly denní příjem selenu z více než 80 %. Bazální minimum bylo dosaženo u obou diet každý analyzovaný den. Doporučená denní dávka byla naplněna u diabetické diety. Nižší procento plnění bylo zaznamenáno ve stravě pacientů onkologických.
Selenium is an essential trace element the insufficiency of which is related to numerous serious disorders including oncological diseases and diabetes mellitus. Selenium intake was followed up in the food of said patients in the span of ten days during a summer period and another ten days during a winter period. In the analysed time all meals were prepared from 111 kinds of foodstuffs. The main sources of selenium in both diets were food groups of meat and meat products, cereals, and milk and dairy products which subsidized daily selenium intake by more than 80%. The basal minimum was reached in both diets on every analyzed day. The recommended daily intake was achieved in the diabetic diet. On the other hand, lower daily dose percentage was recorded in the food of oncological patients.
- MeSH
- Diabetes Mellitus, Type 2 therapy MeSH
- Financing, Organized MeSH
- Inpatients MeSH
- Menu Planning MeSH
- Humans MeSH
- Neoplasms therapy MeSH
- Nutritive Value MeSH
- Nutritional Requirements MeSH
- Eating MeSH
- Selenium analysis deficiency MeSH
- Aged MeSH
- Food Service, Hospital MeSH
- Check Tag
- Humans MeSH
- Aged MeSH
Traditional supplements of selenium generally have a low degree of absorption and increased toxicity. Therefore, it is imperative to develop innovative systems as transporters of selenium compounds, which would raise the bioavailability of this element and allow its controlled release in the organism. Nanoscale selenium has attracted a great interest as a food additive especially in individuals with selenium deficiency, but also as a therapeutic agent without significant side effects in medicine. This review is focused on the incorporation of nanotechnological applications, in particular exploring the possibilities of a more effective way of administration, especially in selenium-deficient organisms. In addition, this review summarizes the survey of knowledge on selenium nanoparticles, their biological effects in the organism, advantages, absorption mechanisms, and nanotechnological applications for peroral administration.
- MeSH
- Administration, Oral MeSH
- Drug Delivery Systems methods MeSH
- Humans MeSH
- Nanoparticles administration & dosage chemistry MeSH
- Nanomedicine methods MeSH
- Nanotechnology MeSH
- Food Additives administration & dosage chemistry MeSH
- Selenium administration & dosage pharmacokinetics MeSH
- Intestinal Mucosa drug effects MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Review MeSH
The effect is described of selenium supplemented in an inorganic and organic form on the innate immune response of goats. Though the phagocytic activity (as a marker of the immune function) was found to be lower in organic-Se-treated group than in control (54.5 +/- 4.32 vs. 60.2 +/- 9.15 %), it did not generally exhibit any significant differences; similarly, no differences were found in the phagocytic index. The production of reactive oxygen species (ROS) was determined using the luminol-enhanced chemiluminescence (CL) (estimated as peak CL, integral CL and a peak time after addition of calcium ionophore A23187, opsonised zymosan (OZP) and phorbol-12-myristate-13-acetate as effectors. A significant ROS increase reflected in integral CL and a peak time was found in the inorganic-Se-treated group when OZP was used as activator; other parameters did not exhibit significant changes. The supplementation of Se in inorganic form can thus be seen to influence positively the innate immune system of kids.
- MeSH
- Inorganic Chemicals administration & dosage MeSH
- Phagocytosis drug effects MeSH
- Financing, Organized MeSH
- Immunologic Factors administration & dosage MeSH
- Goats MeSH
- Organic Chemicals administration & dosage MeSH
- Immunity, Innate drug effects MeSH
- Reactive Oxygen Species metabolism MeSH
- Selenium administration & dosage MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
