Contribution of calcium and other dietary components to global variations in bone mineral density in young adults.

A research project on comparative international studies of osteoporosis using isotope techniques was organized by the International Atomic Energy Agency (IAEA) with the participation of 12 countries (Brazil, Canada, Chile, China, Croatia, Hungary, Philippines, Russia, Singapore, South Africa, Turkey, and the United Kingdom). Participating centers in 11 countries (all but the UK) made measurements and collected data on men and women aged 15 to 49 years. In addition to studies of bone mineral density (BMD) at the femoral neck and lumbar spine using DEXA, anthropometric, lifestyle, and nutritional data were also collected. The results of the nutritional studies are reviewed in this paper. Overall, about 8% of the observed variability in spine BMD could be attributed to nutritional factors in men and women; in men, no such relationship could be determined. No single nutritional component (not even calcium) stood out as being of particular importance across all participating centers.

Fluorine determination in human and animal bones by particle-induced gamma-ray emission.

Fluorine was determined in the iliac crest bones of patients and in ribs collected from post-mortem investigations by particle-induced gamma-ray emission based on the 19F(p,p'gamma)19F reaction, using 2.0/2.5 MeV protons. The results indicate that for 68% of the human samples the F concentration is in the range 500-1999 microg g(-1). For comparison purposes fluorine was also determined in some animal bones; in some animal tissues lateral profiles of fluorine were measured.

In vivo energy dispersive X-ray fluorescence for measuring the content of essential and toxic trace elements in teeth.

The calibration and application of a facility, based on energy dispersive X-ray fluorescent analysis (EDXRF) using 109Cd as an excitation source, for in vivo and in vitro estimation of Ca, Pb, Sr and Zn in tooth enamel is described. During the in vivo measurements, the device ensures tissue protection of face and mouth cavity from radiation, and only a small part of tooth surface under study is irradiated. To calibrate the facility, the contents of Ca, Sr and Zn were analyzed simultaneously in the enamel of 50 teeth by EDXRF and instrumental neutron activation analysis (INAA). Standards prepared from powdered tooth enamel with additions of chemically pure lead compounds were used to calibrate for lead graduation. Enamel calcium is suggested as an internal standard during in vivo EDXRF of teeth. The content of enamel Sr, Zn and Pb was determined by EDXRF in 35 permanent intact teeth of teenagers and adults. It was shown that lead concentration didn't exceed 3 micrograms/g for all the teeth.

X-ray fluorescence analysis of bromine for the estimation of extracellular water.

Three methods for extracellular water (ECW) estimation via analysis of the corrected bromine space (CBS) are presented. The methods are based on the application of stable bromine as an indicator and X-ray fluorescence analysis (XRF). The content of stable bromine can be determined in samples of ulna vein blood and daily urine (the first method) as well as in microsamples of finger blood (the second method) and mixed non-stimulated saliva (the third method). The precision and accuracy of the methods were compared using the results of both repeated analysis and CBS estimation by different procedures including the routine method with 82Br as indicator. A device for XRF with a Si(Li) detector and 109Cd sources was developed for bromine determination in biological fluids.

Normal human intrathyroidal iodine.

Excessive or deficient iodine intake results in a variety of human thyroid dysfunction and disorder. The main part in the etiology of these disorders relates to the concentrations of intrathyroidal iodine which is important to regulate thyroid function and state. Instrumental neutron activation and X-ray fluorescent analyses were used to study the age dynamics of intrathyroidal iodine. Concentration and the total content of iodine in the thyroid were estimated in necropsy samples of 70 men and 20 women aged 2-87. Both thyroid lobes were weighed, lyophilised and homogenised. Iodine was analysed in approximately 50-mg samples. The mean intrathyroidal iodine concentration (mean +/- S.E.) of a normal subject aged 26-65 averaged 345 +/- 21 micrograms g-1 dry tissue in non-endemic goitre region with no obligatory salt iodination. Maximum iodine concentration was found to be 494 +/- 65 micrograms g-1 (P < 0.05) for the age of 16-25. A statistically reliable second increase of iodine was shown for the elderly which was 668 +/- 60 micrograms g-1 (P < 0.001) for the age over 65. Human intact thyroid weight for the age over 15 does not change and averages 14.2 +/- 0.4 g. Both left and right lobes of intact thyroid do not differ in weight, iodine concentration and the total content. An inverse correlation was found between thyroid weight and intrathyroidal iodine concentration (-0.32, P < 0.01). The range of intrathyroidal iodine parameters is wide enough to provide a possible explanation for the particular sensitivity of some population to both excessive and deficient iodine intake. Similarity of intrathyroidal iodine age dynamics and incidence of new cases of thyroid carcinoma were to confirm the hypothesis of intrathyroidal iodine importance in cancer etiologies suggested before.

Instrumental neutron activation analysis of essential and toxic elements in child and adolescent diets in the Chernobyl disaster territories of the Kaluga Region.

The main etiologic factor of various diseases, syndromes and pathologic conditions is an excess, deficiency or imbalance of trace element intake into the human body. Children seem to be the most sensitive to each change of trace element homeostasis. An inadequate essential trace element intake may result in an undesirable consequence that can apparently multiply against a background of additional unfavourable environmental influence such as high levels of radiation, organic and inorganic toxins, etc. Thus, the quality control of children's diets assumes urgent importance within the regions covered by the Chernobyl disaster. Instrumental neutron activation analysis was used to estimate contents of Ag, Br, Ca, Cl, Co, Cr, Cs, Fe, Hg, K, Mg, Mn, Na, Rb, Sb, Sc, Se, Sr, and Zn in the diets of children and adolescents. Diets were chosen from day care centre, boarding school and technical college cafeterias situated within the south and south west territories of the Kaluga Region, where radionuclide contamination ranges up to 15 Ci/km2. Ca and Zn deficiencies were found in the diets of children and adolescents aged 7-18. The Ca intake is only 212 mg/day, 5 times lower than that in developed countries. The Zn intake is 6.8 mg/day, 2 times lower than the level recommended by the WHO.

Zinc concentration in human prostatic fluid: normal, chronic prostatitis, adenoma and cancer.

Radionuclide induced energy dispersive X-ray fluorescence was used to estimate zinc content in prostatic fluid in normal, chronic prostatitis, adenoma and cancer cases, Groups of patients suffering from chronic prostatitis, adenoma and malignant tumours consisting of 28, 28 and 13 men, respectively, were examined. The control group included 22 healthy volunteers. Expressed prostatic fluid was obtained by digital rectal massage. The zinc concentration of intact prostatic fluid was 590 +/- 45 (SE) micrograms/ml. Almost no difference was found between the zinc concentration for chronic prostatitis and for adenoma, and those for normal levels being 455 +/- 60 (SE) and 540 +/- 50 (SE) micrograms/ml, respectively. Prostatic neoplasm resulted in a significant decrease of zinc secretion, with the concentration averaging 34.7 +/- 9.6 micrograms/ml, p < 0.000001.