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Biomedical subjects

R M Parr

Publications and source records attributed to R M Parr.

At least 19 recordsLinked to original sources
PubMed2004

Estimation of internal radiation dose to the adult Asian population from the dietary intakes of two long-lived radionuclides.

Daily dietary intakes of two naturally occurring long-lived radionuclides, 232Th and 238U, were estimated for the adult population living in a number of Asian countries, using highly sensitive analytical methods such as instrumental and radiochemical neutron activation analysis (INAA and RNAA), and inductively coupled plasma mass spectrometry (ICP-MS). The Asian countries that participated in the study were Bangladesh (BGD), China (CPR), India (IND), Japan (JPN), Pakistan (PAK), Philippines (PHI), Republic of Korea (ROK) and Vietnam (VIE). Altogether, these countries represent more than 50% of the world population. The median daily intakes of 232Th ranged between 0.6 and 14.4 mBq, the lowest being for Philippines and the highest for Bangladesh, and daily intakes of 238U ranged between 6.7 and 62.5 mBq, lowest and the highest being for India and China, respectively. The Asian median intakes were obtained as 4.2 mBq for 232Th and 12.7 mBq for 238U. Although the Asian intakes were lower than intakes of 12.3 mBq (3.0 ug) 232Th and 23.6 mBq (1.9 ug) 238U proposed by the International Commission on Radiological Protection (ICRP) for the ICRP Reference Man, they were comparable to the global intake values of 4.6 mBq 232Th and 15.6 mBq 238U proposed by the United Nation Scientific Commission on Effects of Radiation (UNSCEAR). The annual committed effective doses to Asian population from the dietary intake of 232Th and 238U were calculated to be 0.34 and 0.20 microSv, respectively, which are three orders of magnitude lower than the global average annual radiation dose of 2400 microSv to man from the natural radiation sources as proposed by UNSCEAR.

Adult↗
PubMed2004

Dietary intakes of seven elements of importance in radiological protection by asian population: comparison with ICRP data.

Within the framework of a Coordinated Research Project (CRP) organized by the International Atomic Energy Agency, Vienna, the daily dietary intakes of seven elements by adult populations living in nine Asian countries were estimated. The countries that participated in the study were Bangladesh, China, India, Indonesia, Japan, Pakistan, Philippines, South Korea (Republic of Korea, ROK), and Vietnam and together they represented more than half of the world population. The seven elements studied were calcium, cesium, iodine, potassium, strontium, thorium, and uranium. These elements have chemical and biological similarity to some of the radionuclides abundantly encountered during nuclear power production and therefore data on these elements could provide important information on their biokinetic behavior. Analyses of diet samples for these seven elements were carried out using highly sensitive and reliable analytical techniques. One thousand one hundred and sixty analytical determinations were made on two hundred and twenty samples of typical diets consumed in these countries to estimate the daily intakes of these elements by the adult Asian population. The median daily dietary intakes for the adult Asian population were found to be 0.45 g calcium, 7 microg cesium, 90 microg iodine, 1.75 g potassium, 1.65 mg strontium, 1 microg thorium, and 1 microg uranium. When compared with the intakes proposed for ICRP Reference Man by International Commission for Radiological Protection, these intakes were lower by factors of 0.41 for calcium, 0.7 for cesium, 0.45 for iodine, 0.53 for potassium, 0.87 for strontium, 0.33 for thorium, and 0.52 for uranium. The lower daily intakes of calcium, cesium, and iodine by Asian population could be due to significantly lower consumption of milk and milk products, which are rich in these elements. The significantly lower intake of calcium in most of the Asian countries may lead to higher uptake of fission nuclide 90Sr and could result in perhaps higher internal radiation dose. The use of highly sensitive and reliable analytical methods resulted in accurate and lower intake values obtained for thorium and uranium, which suggest that radiation dose from their ingestion at natural background levels is likely to be lower than what may be concluded from ICRP data.

Asia↗
PubMed2004

Contents of cesium, iodine, strontium, thorium, and uranium in selected human organs of adult asian population.

Contents of cesium, iodine, strontium, thorium, and uranium in some selected human organs were estimated for adult Asian population using data obtained in four Asian countries: China, India, Philippines, and Republic of Korea, as part of a Coordinated Research Program of the International Atomic Energy Agency on "Ingestion and Organ contents of elements of importance in radiation protection." These countries together represent more than 40% of the world population. Highly sensitive analytical techniques were employed to measure cesium in skeletal muscle, iodine in thyroid, strontium in skeleton, thorium and uranium in skeleton, liver, kidneys, and lungs where, in comparison to other organs, these elements are present in higher concentrations. The organ contents for adult Asian population, when compared with the corresponding data proposed for Reference Man by International Commission on Radiological Protection (ICRP), showed about 40 times lower kidneys content and about 10 times lower skeleton content of uranium. The content of thorium in skeleton for Asian population was also half of the ICRP Reference Man value. Interestingly, organ contents for the other elements such as iodine in thyroid, cesium in skeletal muscle, and strontium in skeleton were comparable for Asian and the Caucasian population (represented by ICRP Reference Man). Organ contents for these elements were also calculated by applying the new ICRP models of these elements to their daily intakes. The comparison of the calculated and measured organ contents showed that despite uncertainties in the organ content values arising due to the inter-country variations in daily dietary intakes, the contents were within a factor of two to three. This observation is significant since human data both on organ contents and ingestion were obtained at environmental level of intakes. The study suggests that currently available ICRP models for these elements are quite realistic.

Adult↗
PubMed2002

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.

Absorptiometry, Photon↗
PubMed1999

Acquisition of improved reference values for cesium, iodine, strontium, thorium, and uranium in selected NIST reference materials.

As part of a study on the ingestion and organ content of some trace elements of importance in radiological protection, additional work has been undertaken to acquire improved reference values for cesium, iodine, strontium, thorium, and uranium in four selected reference materials provided by the US National Institute of Standards and Technology. The materials are SRM-1548 Total Diet, SRM-1548a Typical Diet, SRM-1486 Bone Meal, and RM-8414 Bovine Muscle. A coordinated study was undertaken with the help of seven selected laboratories in five countries. Instrumental and radiochemical neutron activation analysis and inductively coupled plasma-mass spectrometry were the analytical main techniques used.

Animals↗
PubMed1999

IAEA Internet database of natural matrix reference materials.

The International Atomic Energy Agency maintains a database on internationally available certified reference materials of natural origin. The database was updated in 1998 and prepared for an Internet implementation. A user-friendly structure was created, providing two main pathways for browsing, either according to the matrix classification or the producer's name. The database presently contains over 20,000 values for 480 measurands and 1085 reference materials from 43 different producers. Most of the materials entered contain values for trace and minor elements (66%).

Database Management Systems↗
PubMed1999

Health-related monitoring and assessment of airborne particulate matter. An overview of recent IAEA programs.

Since 1992, the International Atomic Energy Agency (IAEA) has been promoting studies of air pollution using a standard design of air sampler that provides separation on filters into two size fractions with cutoffs of 2.5 and 10 microns (approximately). These are the size ranges presently considered to have the most important health consequences. Such filter samples are highly amenable to analysis using nuclear and related techniques. After reviewing some of the health effects of airborne particulate matter and current air quality standards and guidelines, this article provides an overview of current and recent IAEA programs in this area, which involve collaborative activities with participants in more than 40 countries.

Air Pollutants↗
PubMed1999

Biomonitoring of air pollution as exemplified by recent IAEA programs.

Biomonitoring is an appropriate tool for assessing the levels of atmospheric pollution, having several advantages compared with the use of direct measurements of contaminants (e.g., in airborne particulate matter, atmospheric deposition, precipitation), related primarily to the permanent and common occurrence of the chosen organisms in the field, the ease of sampling, and trace element accumulation. Furthermore, biomonitors may provide a measure of integrated exposure over an extended period of time and are present in remote areas and no expensive technical equipment is involved in collecting them. They accumulate contaminants over the exposure time and concentrate them, thus facilitating analytical measurements. Based on large-scale biomonitoring surveys, polluted areas can be identified, and by applying appropriate statistical tools, information can be obtained on the type of pollution sources and on the transboundary transport of atmospheric pollutants. The International Atomic Energy Agency is including the research on biomonitors in its projects on health-related environmental studies. Biomonitoring activities from several coordinated research projects on air pollution are presented, and results from an international workshop are discussed. In addition, activities in supporting improvement quality in the participating laboratories are outlined.

Air Pollutants↗
PubMed1998

A review of radiologically important trace elements in human bones.

The authors recently compiled and reviewed the literature for minor and trace elements in human bones and teeth as a part of an International Atomic Energy Agency (IAEA) study. Various aspects of elemental composition, analytical methodologies, quality assurance and quality control methods for hard tissue analysis were evaluated. Important data on selected radiologically important elements (Cs, Pu, Ra, Sr, Th, and U) in calcified tissue from various countries are discussed. The results of this compilation study suggest a need for new reference materials with matrix properties similar to bones including one with separated cortical and trabecular segments.

Adult↗
PubMed1994

Toxic heavy metals and other trace elements in foodstuffs from 12 different countries. An IAEA coordinated research program.

A research program related to the assessment of toxic heavy metals and essential trace elements in foodstuffs has been carried out in 12 countries under the auspices of the IAEA. The main purpose of this program was to obtain data on the elemental concentrations of potentially toxic elements in foodstuffs in various countries, and to compare them with the maximum permissible levels specified in national legislation and international guidelines. High-priority elements for this study were As, Cd, Cr, Pb, Hg, and Se. Also of interest, but of lower priority, were Sb, Cu, and Zn. Emphasis was placed on the use of nuclear and nuclear-related analytical techniques, complemented by conventional methods, and on quality assurance.

Food Analysis↗
PubMed1994

Trace element contents in food determined by neutron activation analysis and other techniques.

Advances in analytical methodology and sophisticated instrumentation introduced during the last few decades have not only helped to recognize the presence of a large number of essential and toxic trace elements in biological materials and food stuffs, but also added a new dimension in our understanding of their role in health and disease. In deficiency states, most essential trace elements cause health problems. The trace element problem as a public health issue has a very low priority in developing countries. Daily dietary intake data based on well-conducted studies are limited in many parts of the world. The present authors are in the process of generating data for the intake levels of a number of major and minor inorganic elements both in developed and developing countries. The results so far obtained show wide variations. The intake levels of several elements, including potassium, magnesium, zinc, copper, and selenium, are below the current recommended levels. The concentration of toxic metals, such as aluminum, cadmium, lead, and mercury, are within acceptable limits in most of the diets analyzed.

Adolescent↗
PubMed1994

Programs of the IAEA utilizing nuclear analytical techniques in the life sciences.

Nuclear analytical techniques have an important role in the IAEA in life sciences programs relating to human health. A major effort has recently been devoted to the determination of dietary intakes of trace elements, including studies in some countries affected by the Chernobyl accident. The same accident stimulated interest in using 129I (as determined by NAA and other techniques) to trace the distribution of fission products in the environment. Other research topics concern solid wastes, air pollution, exposure to mercury in selected human populations, and osteoporosis (including NAA studies of trace elements in human bone). Much of the IAEA's work is concerned with analytical quality control; new reference materials in preparation include lichen (for trace elements) and human hair (for total and methyl mercury).

Animals↗
PubMed1991

Minor and trace elements in human milk from Guatemala, Hungary, Nigeria, Philippines, Sweden, and Zaire. Results from a WHO/IAEA joint project.

Concentrations of As, Ca, Cd, Cl, Co, Cr, Cu, F, Fe, Hg, I, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sb, Se, Sn, V, and Zn were determined in human whole milk samples from Guatemala, Hungary, Nigeria, Philippines, Sweden, and Zaire; in most of these countries, three groups of subjects representing different socioeconomic conditions were studied. Analytical quality control was a primary consideration throughout. The analytical techniques used were atomic absorption spectrophotometry, atomic emission spectrometry with an inductively coupled plasma, colorimetry, electrochemistry, using an ion-selective electrode and neutron activation analysis. The differences between median concentrations of Ca, Cl, Mg, K, Na, and P (minor elements) were lower than 20% among the six countries. Among trace elements, concentrations observed in Filipino milk for As, Cd, Co, Cr, Cu, F, Fe, Mn, Mo, Ni, Pb, Sb, Se, and V were higher than for milk samples from other countries. The remaining five countries showed a mixed picture of high and low values. In the case of at least some elements, such as, F, I, Hg, Mn, Pb, and Se, the environment appears to play a major role in determining their concentrations in human milk. The nutritional status of the mother, as reflected by her socioeconomic status, does not appear to influence significantly the breast milk concentrations of minor and trace elements. Significant differences exist between the actual daily intakes observed in this study and current dietary recommendations made by, for example, WHO and the US National Academy of Sciences. These differences are particularly large (an order of magnitude or more!) for Cr, F, Fe, Mn, and Mo; for other elements, such as, Ca, Cu, Mg, P, and Zn, they amount to at least a factor 2. In the opinion of the present authors, these findings point to the need for a possible reassessment of the dietary requirements of young infants with respect to minor and trace elements, particularly for the elements Ca, Cr, Cu, F, Fe, Mg, Mn, Mo, P, and Zn.

Democratic Republic of the Congo↗
PubMed1989

Trace element analysis in environmental and occupational health: box plot representation of elemental composition results.

Box plots are used in the visual representation of large data sets and in exploratory data analysis. They display batches of data with five values being used to describe the data set. These are the median, the upper and lower extremes of the range of values and the 75 and 25 percentiles. A notch about the median, e.g. at the 95 percent level of significance, can be incorporated in the display allowing the difference between the medians of different sets to be established. The method, although not recently established, has so far found little application in the analytical field. Hence, in an effort to strengthen its applicability, the features and capabilities of box plots, in terms of data reporting and insight into the data set, are here described through elemental composition studies in relation to environmental and occupational health.

Cobalt↗
PubMed1988

Concentrations of some trace elements in hair, liver and kidney from autopsy subjects--relationship between hair and internal organs.

Autopsy samples of hair, liver and kidney cortex from 30 Swedish subjects (Caucasian) were analysed for Ag, Co, Cr, Hg, Sb, Se and Zn by neutron activation analysis (NAA). The following elements were observed to have higher concentrations in hair than in liver and kidney cortex: Ag, (Co), Cr and Hg (on a dry weight basis). Selenium was highly concentrated in kidney cortex, and Fe in liver. The observed concentrations of most of the elements were very variable for each tissue. In particular, Co values for hair showed more than a 5000-fold difference. However, Se values for hair were relatively constant. A highly significant positive correlation was observed between Hg concentrations in hair and kidney cortex. Somewhat weaker correlations were found between Hg in kidney cortex and liver and Se in hair and kidney cortex. The concentration of Co in liver correlated with that in kidney cortex. It was concluded that, with the exception of mercury, and to a lesser degree selenium, hair analysis did not provide a useful measure of the trace element status of the subjects included in this study.

Autopsy↗