[Effects of an increased intake of various elements, trace elements and nitrate in farm-produced feed on the health and fertility of dairy cows].
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Starting from the importance of the trace elements in basic biochemical mechanisms from the human organism, the present role of trace elements therapy, as part of allopathic therapy, is discussed. The ideal properties of trace elements, the therapeutic concepts regarding trace elements, the main pharmaceutical forms that contain them, and their most important uses are presented.
The analysis of trace elements is performed by proton-induced X-ray emission. The process is most effective if the velocity of the exciting particles--protons--is similar to the velocity of the electron on its orbit in the simple atomic model of Bohr. For K-shell electrons of the elements with 15 less than or equal to z less than or equal to 40 this requires proton energies of a few MeV, available from electrostatic van de Graaf accelerator machines. After knocking out the K-shell electron, the empty place is filled up by electrons jumping from higher orbits with simultaneous emission of characteristic X-rays, which are registered with a cooled Si (Li) detector. By a set of electrodes the beam can be swept across the specimen surface. Therefore this method yields an excellent correlation of trace element distribution within the morphological structure of organic tissue. In the present study the sweep went along a line perpendicular to the arterial wall layers (aortic, renal artery and heart muscle) of normotensive and spontaneously hypertensive rats. Along this line all elements and trace elements are recorded simultaneously. These are P, S, Cl, K, Ca, Fe, Cu, Zn, Br and Sr. The trace element content of the aortic wall and the renal artery, of 22 spontaneously hypertensive and 11 normotensive rats and of human heart muscle was investigated. The results demonstrate that Zn was only detected in the muscle-containing layers of the arteries. There was no different distribution between hypertensive and normotensive rats. However, Ca2+ was mainly detected in the smooth muscle-containing tunica media of hypertensive rats.(ABSTRACT TRUNCATED AT 250 WORDS)
Changes in the properties of the skin barrier should have correlates in the physiological status of the differentiating epidermal cells. However, the quantitative distributions of physiologically important elements and trace elements of the skin has been a neglected area of research for lack of tools to investigate this highly differentiated tissue. With the event of the particle probes, the electron microprobe and the scanning proton microprobe, it has become possible to investigate different aspects of normal skin physiology as well as pathophysiological processes. In addition penetration profiles of allergenic metals can be demonstrated with the trace element sensitive proton probe. Future approaches to the study of skin physiology in normal and pathological conditions should incorporate other techniques including immunological and biochemical tagging of particular cells to achieve a broad basis for interpretations of data.
Ten macro elements and trace elements were directly determined in the 1992 total diet study conducted in four districts of China from north to south. The intake of these elements was evaluated. The levels of intake for seasonal variation and for different age groups were reported. The results showed that the intakes of Ca, P, K, Mg, Zn, Se and Cu were low in children. The intake of Ca, P and Zn was insufficient for adults. The intakes of other seven elements reached or approached their RDA levels, but there were big differences among the 4 districts. The relationships between intakes of Ca/P and Na/K as well as Fe and Cu and iron difficiency anemia were discussed.
Routinely, the macronutrient contribution is thoroughly studied when a patient is included in a total parenteral nutrition (TPN) program. However, it must be kept in mind that along with macronutrients, micronutrients, oligoelements and vitamins are also administered, and these must be taken into account. At present, for instance, the importance of oligoelements has become evident, and clinical conditions of oligoelement deficiency have been described in many cases even when the minimum daily requirements had been met. This study centers on the importance of evaluating oligoelement and trace element levels when patients are admitted into the ICU and were included into a total parenteral nutrition (TPN) program. An assessment of the serum calcium (Ca), phosphorus (P), magnesium (Mg), zinc (Zn), copper (Cu), iron (Fe) and transferrin (Tfe) levels was done on 55 septic patients who underwent abdominal surgery was done on admission to the ICU. Transferrin was measured of serve as an indicator of metabolic damage. A description of the methods used in analytical assessment, a presentation of normal values, the statistical management of each of the elements under study and the interpretation of the results obtained has been done. The discussion is based on the changes detected in the patients' serum levels on admission to the unit, showing low iron, transferrin, zinc and calcium values and normal magnesium, phosphorus and copper figures. The conclusion arrived at suggests that the daily parenteral supplements of these elements should be higher than those recommended by the American Medical Association (AMA) and by other authors.
A vitamin and trace element supplement containing recommended dietary amounts or "safe and adequate" levels was given to ten healthy subjects for 12 to 35 weeks. Plasma levels of selenium and zinc, activity of glutathione peroxidase in plasma and platelets, whole blood manganese, activity of superoxide dismutase in hemolysate, activity of alkaline phosphatase in serum, iron status indices and urinary excretion of zinc and selenium were measured. A small but significant change in plasma selenium from 1.01 +/- 0.14 mumol/L to 1.08 +/- 0.10 mumol/L was observed after two weeks. However, at the end of the supplementation plasma selenium levels did not differ from the initial levels. Plasma glutathione peroxidase levels showed a similar trend and changes in glutathione peroxidase activity in platelets were also transient. A small increase in serum zinc values was observed after 30 weeks of supplementation. No significant changes were observed in the other blood and urine parameters studied. In seven of the subjects absorption of zinc, manganese and selenium was measured after 30-31 weeks of supplementation by a radionuclide technique. The absorption of selenium and manganese after long term supplementation was 30-50% lower than observed previously in non-supplemented subjects. In conclusion, present available indices of trace element status are only to a limited extent affected by 30 weeks of a doubling of the normal dietary intake.
The trace element status of nine households from the Wosera subdistrict of Papua New Guinea was assessed. Individual weighed three-day dietary intakes were carried out in April during the hungry season when yams were not eaten and in July when yams were available. Representative staple food items analyzed 'as eaten' for energy, protein, Ca, Mn, Cu and Zn and mean daily energy and nutrient intakes calculated. Hair samples were also collected in July, washed, and analyzed for Zn, Cu and Mn by INAA. Seasonal differences in energy, protein, Ca, Fe and Mn intakes were related to changes in yam consumption. The Zn status of the male (M) and female (F) adults and children (Ch) was sub-optimal based on low median hair Zn levels (microgram/g): -F = 78, n = 8; M = 108, n = 8; Ch2-4yrs = 79, n = 8; Ch5-10yrs = 94, n = 7 and inadequate intakes of readily available Zn (mean + SD): - April M + F = 7.0 + 1.6 mg/day; July M + F = 8.2 + 1.5 mg/day; less than three percent Zn from animal products. In contrast their Mn status, as indicated by elevated median hair Mn levels (microgram/g) (F = 25.1; M = 26.3; Ch2-4yrs = 21.5; Ch5-10yrs = 15.2) was high, attributed to elevated Mn intakes (April M + F = 11.0 + 2.2 mg/day; July M + F = 7.5 + 1.4 mg/day). Median hair Cu levels (microgram/g) (F = 7.6; M = 7.5; Ch2-4yrs = 8.6; Ch5-10yrs = 7.8) and mean Cu intakes (April M + F = 2.2 + 0.4 mg/day; July M + F = 3.0 + 0.6 mg/day) were within the range noted for persons consuming predominantly plant-based diets.
Evidence for the influence of trace elements on disease resistance in ruminants is reviewed with emphasis on susceptibility to infection in vivo during the more common deficiencies (copper, selenium and cobalt). Copper deficiency associated with increases in pasture molybdenum increased the susceptibility of lambs to microbial infections. Under experimental conditions, dietary molybdenum decreased the establishment of abomasal and intestinal nematodes but not their pathogenicity to lambs. Molybdenum may enhance inflammatory responses leading to parasite rejection by the host. Decreased incidence of metritis in selenium-treated dairy cows provides a rare example of an association between selenium deficiency and decreased disease resistance. Improved antibody responses following selenium administration have also been found in sheep. Cobalt deficiency has reduced lamb survival and increased susceptibility to parasitic infection transiently in cattle and lastingly in sheep. In copper-, selenium- or cobalt-deficient sheep and cattle, there are many reports of impaired leucocyte and lymphocyte responses to in vitro challenges, but their relevance to disease resistance in vivo is unproven. Disease resistance may have priority for limited micronutrient supplies, leaving other processes vulnerable.
The human placenta as a body component is exposed to several harmful substances, depending upon the environmental conditions encountered. In the case of toxic metals, placental tissue can be regarded as a dual biomarker to assess maternal and fetal health. The average range of concentrations for toxic trace elements in placenta based on wet weight are found to be: cadmium 1-6 ng/g; total mercury 2-13 ng/g; methyl mercury 1-14 microg/g; and lead 5-60 ng/g. The placenta appears to be at least a partial barrier for Cadmium. Cadmium transport includes a broad variety of mechanisms. Once in circulation, it mainly interferes with Ca and Zn transportation. On the other hand, placenta appears to be a weaker harrier for Pb than for Cd. In the case of Hg, predominantly the organic form is absorbed and readily crosses the placenta. In fetal blood, the organic mercury content is equal or even greater than in maternal blood, raising questions on normal fetal development. Placenta as a biomarker could be taken as an alternative to repeated maternal blood sampling for assessing lead exposure in utero. Placenta samples are usually obtained at the time of parturition, a one-time event. Hence, each pregnancy has to be looked upon as an RTM (real time monitoring) process since the affected species is exposed to the placental source of pollutants only during the course of that particular pregnancy.
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Autopsy tissue samples from the brain front lobe, cerebellum, heart, kidney (cortex and medulla), liver, pancreas, spleen and ovary were analysed for AL, B, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr and Zn in 30 (17 women and 13 men) subjects ranging in age from 17 to 96 years at Haukeland University Hospital in Norway. The tissues were selected from macroscopically normal organs and samples were handled according to guidelines recommended to avoid contamination in the pre-analytical phase. Concentration of the trace elements were determined by the inductively coupled plasma atomic emission spectrometry technique (ICP-AES). In most tissues the concentrations of the essential trace elements followed the order Fe> Zn> Cu> Mn> Se> Cr> Co except in the ovary where Se was higher than Mn. The liver was the major site of deposition for Co, Cu and Mn as well as the spleen for Co, brain front lobe for Cu and pancreas for Mn. Ba, Sr and Ni built up in the ovary foLLowed by the kidney. Older subjects accumulated Ba and Sr in most tissues, whereas Al accumulated in the kidney cortex and Cd in the brain cerebellum. Generally males had higher concentrations of trace elements in the different tissue sampLes than females with the exception of Mn in the brain front lobe and heart and Sr in the liver. ICP-AES is a useful method to assess the concentration and the profiLe of trace elements in human autopsy tissues.
Neutron activation analysis was used to determine the distribution of trace elements in human hair. Hair samples were obtained from five infants (two to seven years of age) with hair length ranging from 15 to 40 cm. The hairs were divided into segments, each of 2.5 cm, starting from the scalp end and trace elements were analysed in each segment. Concentrations of I, Mg, Ca and Cu increased from the scalp end to the tip. Concentrations of Cl and Br decreased inversely. Different profiles of the concentrations of Hg, Se, Ca and Mn were seen in each sample. These results were discussed with reference to the indication of environmental pollution.
For human beings trace elements are essential nutrients with a gamut of functions. They are for instance indispensable components of many enzymes, so they have some regulatory functions and they may affect immune reactions and free radical generation. Abnormalities of trace elements are primarily the result of uremia, and they may be further modified and sometimes greatly exacerbated by the dialysis procedure. The role of trace elements in hemodialysis (HD) patients has not yet been fully characterized. To prevent some complications in chronic HD patients, it is very important to regulate the levels of trace elements by adequate water treatment. Reverse osmosis is able to prevent the accumulation of the majority of trace elements in the patients. Zinc supplementation may be recommended for patients with proven zinc deficiency, but for all chronic renal failure patients it is questionable. Selenium deficiency is to be suspected in dialyzed patients and selenium supplementation may be beneficial (increasing glutathione peroxidase activity, cardioprotective effect, immunostimulatory properties) for chronic renal failure patients. Supplementation with a trace element may be indicated when its depletion was unequivocally documented and when there is evidence of the positive effects of this element on the quality of life of the dialyzed patients.
Essential trace elements are required by man in amounts ranging from 50 micrograms to 18 milligrams per day. Acting as catalytic or structural components of larger molecules, they have specific functions and are indispensable for life. Research during the past quarter of a century has identified as essential six trace elements whose functions were previously unknown. In addition to the long-known deficiencies of iron and iodine, signs of deficiency for chromium, copper, zinc, and selenium have been identified in free-living populations. Four trace elements were proved to be essential for two or more animal species during the past decade alone. Marginal or severe trace element imbalances can be considered risk factors for several diseases of public health importance, but proof of cause and effect relationships will depend on a more complete understanding of basic mechanisms of action and on better analytical procedures and functional tests to determine marginal trace element status in man.
Trace elements levels in tissues show changes in various diseases including inborn errors of metabolism. Such changes may be primary or secondary due to stress or diseases of the liver and gastrointestinal tract. Measurement of trace elements in these cases may be essential both for diagnostic and therapeutic purposes. Trace element measurements can also be useful in other areas of clinical interest including nutrition, toxicity and therapy with inorganic pharmaceutical agents. The available techniques for measuring trace elements in tissues are summarized and the various problems of each are discussed.
The bioavailability of the trace elements iron, zinc, copper and manganese from human milk is high compared to cow's milk and infant formulas. This high bioavailability may be explained by the presence of lactoferrin in human milk, which may facilitate iron and manganese uptake via an intestinal receptor for this protein. High concentrations of ascorbate and citrate may also facilitate uptake of trace elements from human milk and milk formulas, while a high concentration of casein in cow's milk and cow's milk formulas may limit trace element absorption from these diets. Trace element absorption from soy formula is low, mostly due to the presence of phytate but possibly also due to some protein fraction. Trace elements sharing absorptive pathways compete for uptake, and imbalances in the ratios between trace elements (Fe/Zn, Zn/Cu, Fe/Mn) in formulas may impair trace element absorption. These factors need to be taken into consideration when setting upper limits for trace elements in formulas. With our present knowledge, an upper limit for iron of 14 mg/l, for zinc, 12 mg/l, copper, 1.2 mg/l, and manganese, 0.6 mg/l are suggested. The capacity of infants to homeostatically adapt to varying intakes of trace elements needs to be further evaluated.