Biological Trace Element Research Articles

Trace Elements in Medicine and Biology

Trace Elements in Medicine and Biology

Trace elements in some wild plants from the shores of the high dam lake and the adjacent desert, as determined by atomic absorption spectroscopy

Fifteen biological trace elements essential to plants, man and animals: silver, gold, cobalt, copper, chromium, nickel, lead, iron, magnesium, manganese, potassium, sodium, strontium, zinc and calcium, were estimated and analysed in some wild plants from near the shores of the High Dam Lake and the adjacent desert at Aswan (Egypt). These plants are: Panicum coloratum, Astragalus vogehi, Echinochloa colonum, Glinus lotoides, Tamarix nilotica, Fagonia indica, Salsola imbricata and Aerva javanica. The element content of the analysed plants can be classified into three groups viz. major, minor and trace based on the conventional classification of 1–5·8% as major, 1–650 p.p.m. as minor and 1–900 p.p.b. as trace. The results show Ca as major element in all plants, with Fe, Mg, Mn, Na, Sr and Zn as minor, while the remainder are present in trace amounts. It was observed that Glinus lotoides contained higher concentrations of Ag, Au, Co, Cu, Ni, Pb, Fe and Sr than the others while Echinochloa colonum contained higher concentrations of Cr, Fe, K and Mn than the others. The present study gives a new picture about the ion antagonism in these plants and also their uses as therapeutic agents for man and in the treatment of mineral deficiency in animals. flame atomic absorption spectroscopy was used to detect the limits of the elements; the method was sensitive to 3 p.p.b.

Developments in tomographic methods for biological trace element research.

Neutron-induced gamma-ray emission tomography for quantitative determination of concentration and distribution of elements in a selected plane through a biological specimen is briefly explained and applied by way of illustration to the analysis of gallstones. A system capable of carrying out studies of the binding site of 75Se is different matrices using time differential perturbed angular correlation spectroscopy is also briefly described. Developments in the detector technology of positron emission tomography have allowed small-diameter imaging devices to be built for in vivo preclinical evaluation of new tracers in small animals and are discussed in the context of a proposed experiment combining the techniques mentioned above.

Zinc, copper and selenium in reproduction.

Of the nine biological trace elements, zinc, copper and selenium are important in reproduction in males and females. Zinc content is high in the adult testis, and the prostate has a higher concentration of zinc than any other organ of the body. Zinc deficiency first impairs angiotensin converting enzyme (ACE) activity, and this in turn leads to depletion of testosterone and inhibition of spermatogenesis. Defects in spermatozoa are frequently observed in the zinc-deficient rat. Zinc is thought to help to extend the functional life span of the ejaculated spermatozoa. Zinc deficiency in the female can lead to such problems as impaired synthesis/secretion of (FSH) and (LH), abnormal ovarian development, disruption of the estrous cycle, frequent abortion, a prolonged gestation period, teratogenicity, stillbirths, difficulty in parturition, pre-eclampsia, toxemia and low birth weights of infants. The level of testosterone in the male has been suggested to play a role in the severity of copper deficiency. Copper-deficient female rats are protected against mortality due to copper deficiency, and the protection has been suggested to be provided by estrogens, since estrogens alter the subcellular distribution of copper in the liver and increase plasma copper levels by inducing ceruloplasmin synthesis. The selenium content of male gonads increases during pubertal maturation. Selenium is localized in the mitochondrial capsule protein (MCP) of the midpiece. Maximal incorporation in MCP occurs at steps 7 and 12 of spermatogenesis and uptake decreases by step 15. Selenium deficiency in females results in infertility, abortions and retention of the placenta. The newborns from a selenium-deficient mother suffer from muscular weakness, but the concentration of selenium during pregnancy does not have any effect on the weight of the baby or length of pregnancy. The selenium requirements of a pregnant and lactating mother are increased as a result of selenium transport to the fetus via the placenta and to the infant via breast milk.

Effective tools for the trace element characterization of tissues: neutron activation analysis and voltammetry

The National Biomonitoring Specimen Bank at the National Institute of Standards and Technology applies a variety of techniques for extensive characterization of banked samples. To determine a large number of trace elements in small samples at low levels, instrumental neutron activation analysis has been combined with voltammetry. The two methods produce high quality data for thirty pollutant and biological trace elements. Results on archived specimens of human livers and intercomparisons of the two methods are reported.

Presence and significance of naturally occurring chemical elements of the periodic system in the plant organism and consequences for future investigations on inorganic environmental chemistry in ecosystems

After acceptance of the “Element Concentration Cadasters in Ecosystems” (ECCE) programme as an international project sponsored by the International Union of Biological Sciences (IUBS) at the 24th General Assembly of IUBS in Amsterdam in Sept 1991, the present status of “Biological Trace Element Research” (BTER) is presented here from the biological point of view. Especially information on occurrence, essentially, toxicity and uptake form of all 88 naturally occurring chemical elements is presented. In addition an estimated annual production of each element in the year 2000 and examples of their technical application is given. A scientific proposal for further research work on a local, regional and global scale has been discussed.

4th International meeting on trace elements in medicine and biology

4th International meeting on trace elements in medicine and biology

Emerging Concepts in Bioanalytical Chemistry of Trace Elements

The emerging discipline of Biological Trace Element Research (BTER) demands that adequate considerations be given to both biological and analytical standardization while planning an investigation. Unfortunately, the “bio” dimension of the analytical problem in the BTER area, has been rather slow in unfolding. This lack of appreciation has been a major setback since the early days of BTER, delaying the onset of multidisciplinary approaches that are vital for conceiving meaningful investigations. The presampling factors e.g., biological variations, environmental influences, post-mortem changes and intrinsic (e.g. differences in residence times of various elements in the blood stream) and inadvertent situations (e.g. medico-legal restrictions), are potential sources of serious errors, and require careful evaluation and data interpretation. Yet, these are poorly identified and currently, very little effort is expended to evaluate them. Concerning analytical standardization, progress in technical aspects of sampling are preparation, instrumentation, calibration procedures, increased awareness of matrix interferences and preparation of primary standards have collectively contributed to several improvements. However, information on long-term storage (several years) and its impact on the validity of the stored biomaterial, and experimental findings on the quantitative recovery of biominerals during acid decomposition of different types of sample matrices are still scarce.

4th International Meeting on Trace Elements in Medicine and Biology

4th International Meeting on Trace Elements in Medicine and Biology

Milestones in biological trace element research

Over 100 years ago, macro-scale analytical techniques were used to discover the roles of special compounds (especially of metallic elements) in living organisms, and investigations were focussed on selected proteins and pigments suspected of containing percentage quantities of metals. In contrast, present-day analytical techniques are capable of detecting extremely small quantities and have become routine ultra-trace measurement tools to probe elemental interactions at cellular levels. The scientific achievements connecting these two boundaries are punctuated with an array of analytical developments; some highlighting the phenomenal advances in the measurement technology and others reflecting the exceptional bioanalytical perception and the multi-disciplinary outlook of trace element investigators. An account of the events that contributed to the overall progress in biological trace element research is the essence of this communication.

January 15–18, 1991 3rd congress on trace elements in medicine & biology

January 15–18, 1991 3rd congress on trace elements in medicine & biology

3rd international congress on trace elements in medicine and biology

3rd international congress on trace elements in medicine and biology

Third international congress on trace elements in medicine and biology

Third international congress on trace elements in medicine and biology

Announcements: Third Congress on Trace Elements in Medicine and Biology

Announcements: Third Congress on Trace Elements in Medicine and Biology

Third international congress on trace elements in medicine and biology

Third international congress on trace elements in medicine and biology

In-house biological trace element quality control materials

In-house biological trace element quality control materials

Application of nuclear analytical techniques in the study of trace element role in biology and medicine

The possible applications of nuclear techniques in the study of the role of trace elements in biology and medicine are described. Several examples of the measured variations of trace elements in individual organs and tissue and the interpretation of these data are presented.

Carcinogenesis as the result of the deficiency of some essential trace elements

“Energetic” biological trace elements [gallium (III), germanium (IV), silicon (silica), arsenic (V) and selenium (IV)] occurring in DNA of eukaryotic cells may improve the semiconductor properties of DNA and may influence the mechanisms that control genetic expression at the electronic level. Their roles are postulated as follows: (i) to maintain the level and direction of free sliding electrons in DNA, (ii) to modulate the electron conductivity and hole conductivity of DNA. This specific electronic nature of DNA take the form of magnetic pigeonholes in which an electric pulse is (0), or is not (1) stored as an area of local magnetisation. These types of conductivity occurring in different parts of DNA of different cells could participate in the switch on and switch off of genetic information in gene expression. This model may help to elucidate the mechanism of action of these naturally occurring antitumor agents and may help in understanding the role of trace elements in charge transport of DNA and in carcinogenesis.

The inorganic biochemistry of molybdoenzymes

Molybednum-containing enzymes (Coughlan, 1980; Spiro, 1985) occupy a significant place in the development of the field now termed inorganic biochemistry. The importance of the metal as a biological trace element depends on its involvement in the known, and perhaps other as yet unknown, molybdoenzymes. That it plays a role in biological nitrogen fixation, the process whereby the enzyme nitrogenase in the root nodules of plants converts atmospheric nitrogen into ammonia, was recognized in the 1930s. The metal is also a constituent of a variety of other enzymes, having first been found in a mammalian enzyme, xanthine oxidase, in the 1950s.

Biological trace element research: A multidisciplinary science

The last decade may be regarded as a crucial turning point in new developments in many areas of biological trace element research. It is slowly being recognized as a multidisciplinary science which requires a combination of biological insight and analytical awareness in planning the studies. It is also acknowledged that the complexities involved in dealing with the requirements of trace element research studies in the life sciences demand comprehensive planning of the investigations and use of a variety of techniques, thus bringing together a variety of talents. It cannot be emphasized enough that accurate analytical measurements on biologically and analytically “valid” samples hold the key for success in future biological trace element research studies. These aspects are illustrated.