Human body trace elements

Applications of Activation Analysis in Human Biochemistry Trace Elements Constituents of Tissues and Body Fluids... 

Studies on element metabolism can only be meaningful if the tracer used for isotopic labeling of the element mimics dosely the tracee in the experimental setting, that is, the element or element species/compound under investigation. Similarly to the situation in the human body, essential elements are usually present in plant- or animal-derived food products in the form of functional biomolecules with a distinct biochemical function. Upon digestion in the stomach, the element may or may not be released from the biomolecule or food matrix in ionic form. The same holds true if a specific element compound/species is studied, for example, a mineral salt used for food fortification. The compound may or may not dissolve completely in the gastric juice before leaving the stomach. Dissolution, however, is a precondition for elements to be absorbed in the intestine by common pathways. 

An average of about 7 ppm of bromine is found ia terrestrial plants, and edible foods contain up to 20 ppm. Among animals the highest bromide contents are found ia sea life, such as fish, sponges, and cmstaceans (44). Animal tissues contain 1—9 ppm of bromide and blood 5—15 ppm. The World Health Organization has set a maximum acceptable bromide iatake for humans at 1 mg/kg of body weight per day. In adult males the bromine content ia semm has been found to be 3.2—5.6 p.g/mL, ia urine 0.3—7.0 p.g/mL, and ia hair 1.1—49.0 p.g/mL. Bromine may be an essential trace element as are the other hahdes (45). 

Very careful analysis of trace elements can have a major effect on human life. A notable example can be seen in the career of Clair Patterson (1922-1995) (memoir by Flagel 1996), who made it his life s work to assess the origins and concentrations of lead in the atmosphere and in human bodies minute quantities had to be measured and contaminant lead from unexpected sources had to be identified in his analyses, leading to techniques of clean analysis . A direct consequence of Patterson s scrupulous work was a worldwide policy shift banning lead in gasoline and manufactured products. 

Trace elements found in the human body serving essential biological functions include Mn,... 

After iron, zinc is the second most abundant trace element in the human body an average adult has 3 g of Zn, corresponding to a concentration of about 0.6 mM. Some 95% of zinc is intracellular. It is essential for growth and development in all forms of life, and has been proposed to have beneficial therapeutic and preventative effects on infectious diseases, including a shortening of the length of the common cold in man. 

Determination of the roles of microelements and the human daily requirements can be very difficult due to their low concentrations in the human body and problems connected with the elimination of their constant inflow. Throughout the evolution process, the human body developed mechanisms to regulate the absorption of microelements and balance their levels within required ranges. Therefore, human bodies are adjusted to the natural levels at which those elements are present in the non-polluted environment and in non-contaminated foodstuffs. However, human industrial and economic activities are frequently and widely disturbing the environmental balance and leading to contamination of the environment, including foods, with trace elements. 

Cobalt is found in most natural foods. Although a necessary trace element, it is toxic to humans if ingested in large amounts. The human body does excrete in urine excessive amounts of cobalt compounds such as found in vitamin B ... 

Although some compounds of selenium are poisonous, as an element it is essential in trace amounts for humans. It is recommended that 1.1 to 5 milligrams of selenium be included in the daily diet. This amount can be maintained by eating seafood, egg yokes, chicken, milk, and whole grain cereals. Selenium assists vitamin E in preventing the breakdown of cells and some chemicals in the human body. 

Iron (Fe) is quantitatively the most important trace element (see p. 362). The human body contains 4-5 g iron, which is almost exclusively present in protein-bound form. Approximately three-quarters of the total amount is found in heme proteins (see pp. 106,192), mainly hemoglobin and myoglobin. About 1% of the iron is bound in iron-sulfur clusters (see p. 106), which function as cofactors in the respiratory chain, in photosynthesis, and in other redox chains. The remainder consists of iron in transport and storage proteins (transferrin, ferritin see B). 

As the human body is able to store many minerals, deviations from the daily ration are balanced out over a given period of time. Minerals stored in the body include water, which is distributed throughout the whole body calcium, stored in the form of apatite in the bones (see p. 340) iodine, stored as thyroglobulin in the thyroid and iron, stored in the form of ferritin and hemosiderin in the bone marrow, spleen, and liver (see p. 286). The storage site for many trace elements is the liver. In many cases, the metabolism of minerals is regulated by hormones—for example, the uptake and excretion of H2O, Na, ... 

Over 99% of the human body is composed of only seven elements (Table 6.3), yet trace amounts of a number of elements are essential for vital functions, for example, iron in hemoglobin or zinc in enzymes. 

Selenium is an essential trace element in the human body. This nutrient is an important part of antioxidant enzymes that protect cells against the effects of free radicals that are produced during normal oxygen metabolism. Selenium is also essential for normal functioning of immune system and thyroid gland. 

An accurate determination of copper and zinc traces in human serum samples from the International Measurement Evaluation Programme-17 launched by IRMM (Geel) has been made by isotope dilution TIMS.38 An analytical method for the multi-element determination of metals (Ti, V, Cr, Co, Ni and Mo) potentially released from dental implants and prostheses into human body fluids (in blood and urine) by ICP-MS (double-focusing sector field instrument and quadrupole instrument with octopole collision cell) for medical studies was developed in Sanz-Medel s group.39 The Cr and Co concentrations found in blood samples of patients with chromium-cobalt based alloy varied in the sub-p,gl 1 range and were not significantly higher than the basal levels found by other authors.40... 

Parsons et al.66 reported on the determination of total mercury as a toxic element in urine at the trace level using ICP-MS. The main sources of exposure in the human body are inhalation of Hg vapour released from dental amalgams and the consumption of fish species that accumulate, for example, methyl mercury (MeHg). 

Water accounts for over half the body mass (55%) of the average human. Of the remaining 45%, 19% is protein, 19% is lipid, less than 1% is carbohydrate, and 7% is inorganic material. Nutrients must contain the raw materials that go into the construction of the components of the human body. In addition, nutrients must supply the necessary chemical energy and enzyme cofactors (vitamins and trace metal elements) that are required for the maintenance and growth of the human body. The human body requires nutrients such as water, amino acids, fats, carbohydrates, and major minerals in large amounts. Vitamins and trace metal elements are required in smaller amounts. 

Toulsen et al. (1994) appear to use the term reference interval as synonymous with reference range. In a paper titled Trace element reference values. . . , the authors emphasize that knowledge of the reference intervals (baseline data) for the trace elements in human body fluids and tissues is of paramount importance. ... 

The standard patient has a mass of 70 kg, and the density of the human body is very close to 1 g/mL. What is the body volume of the standard patient in liters Based on this volume and using the data in Table 3.1, determine the molar concentration of iron in the body. Assume all the iron in the body is evenly distributed throughout all tissues. Repeat the calculation on selenium, an element involved in certain oxidation-reduction processes in the body. The lesson of this question is that trace elements can be very trace indeed. 

Yukawa M, Suzuki-Yasumoto M, Amano K, et al. 1980. Distribution of trace elements in the human body determined by neutron activation analysis. Arch Environ Health 35 36-44. 

Lim TH, Sargent T, Kusubov N. 1983. Kinetics of trace element chromium(III) in the human body. 

VersieckJ. 1985. Trace elements in human body fluids and tissues. CRC Crit Rev Clin Lab Sci 22 97-184. 

The evolution of life in a highly aluminum-rich biosphere did not result in a known physiological role of Al3+, which is considered a non-essential trace element of low toxicity in healthy humans. According to various authors, aluminum levels in the human body range from 35 to 40 mg [4]. 

The concentrations in body fluids of trace elements with no known biological functions for maintaining optimal human health, and which are toxic at relatively low concentrations are listed in Table 3. Measurements of these concentrations can be important in monitoring the health of populations occupationally exposed to these elements and in surveys to determine the extent of possible environmental contamination. 

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