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Biomedical subjects

H S Dang

Publications and source records attributed to H S Dang.

At least 19 recordsLinked to original sources
PubMed1998

Point prevalence of secretory otitis media in children in southern Vietnam.

Few reliable data exist on the prevalence of secretory otitis media (SOM) in the Third World. A large epidemiologic cross-sectional study was undertaken in two communes in southern Vietnam to study an urban and a rural community during two different climatic conditions: the dry and rainy seasons. The participants included 3,300 children (6,598 ears) ages 6 months to 10 years. Otolaryngological and medical histories were obtained, and an otolaryngological examination was carried out on 1,669 children in April 1995 (the dry season) and on 1,631 children in December 1995 (the rainy season). Tympanograms were obtained (n = 6,055), 429 of which were type B curves. The overall prevalence of SOM was 7.1%, the highest incidence was at the age of 2 years (with a prevalence of 22%), and there was a significantly higher prevalence of SOM during the rainy season than during the dry season. No significant difference in incidence was found in the urban district as compared to the rural district.

Acoustic Impedance Tests↗
PubMed1995

Distribution of uranium in human organs of an urban Indian population and its relationship with clearance half-lives.

This organ burdens of uranium were estimated for an urban Indian (Bombay) population living in a normal background environment, using the technique of neutron activation analysis, in combination with post-irradiation chemical separation. The total organ burdens were: skeleton > muscle > soft tissue > lungs > kidney > liver > heart. A comparison was made between the observed organ burdens of uranium for skeleton, kidney, and muscle with those obtained by applying the metabolic model of uranium as recommended by International Commission on Radiological Protection (ICRP) to its daily intake by urban population. The observed organ burdens for kidney and muscle were found to be 4 and 70 times higher than the derived burden values; however, the two estimates were similar in the case of skeleton. This observation indicated that the clearance half-lives for uranium present in kidney and muscle tissue are likely to be longer than those reported by ICRP. For skeleton, however, the clearance half-life reported by the ICRP appeared to be reasonable.

Adult↗
PubMed1995

Studies on the biological half-lives of three important radionuclides released in nuclear power reactor operations.

The four important parameters involved in the calculation of internal radiation dose to the human body, per unit intake of a radionuclide are 1) weight and size of the body organs; 2) the biological (retention) half-life of the radionuclide; 3) radiation weighting factors for the type of radiations emanating from the radionuclide; and 4) the organ weighting factors for the organs being irradiated (target organs). Whereas, for a particular radionuclide, the radiation weighting factor and the organ weighting factors may remain constant for all humans, the other two parameters, namely, the organ weights and biological half-life, are population specific and may differ from one population group to another. For a realistic dose estimation, the population specific data on organ weights and biological half-lives for various radionuclides therefore, are needed.

Adult↗
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↗
PubMed1993

Normal concentration and excretion ratio of uranium in serum of normal individuals in India.

This paper reports the normal concentration of uranium in the blood serum of 12 normal volunteers from the Bombay, India area who had no occupational exposure to uranium. Serum samples were analyzed by neutron activation, radiochemical separation, and gamma counting. The mean and median uranium concentrations obtained in the present study are 14 and 13 ng L-1, respectively. The median value was used to obtain the excretion ratio of 41% for uranium excreted in urine compared to that present in the blood serum pool.

Humans↗
PubMed1992

Determining the normal concentration of uranium in urine and application of the data to its biokinetics.

A method was developed to determine the concentration of uranium (238U) in urine. This method involved preconcentration of uranium from urine with calcium phosphate neutron activation followed by simple radiochemical separation. Using this method, it was possible to detect 0.2 ng of 238U. The average and geometric mean concentration of uranium found in urine of subjects from a normal background environment was 12.8 and 9.4 ng L-1, respectively. The concentration of uranium in the urine and the daily intake of uranium by the same population was used to arrive at the gastrointestinal absorption factor (f1) for uranium incorporated in the diet. The f1 factor was estimated to be 1.6%.

Adult↗
PubMed1989

A geochemical basis for endomyocardial fibrosis.

Analysis of hearts of patients dying from endomyocardial fibrosis showed a significantly greater concentration of cerium, a lanthanide present in leafy vegetables and root tubers, than in control hearts. This may be important in the pathogenesis of the disease and provides a geographical basis for the prevalence of the disease in the tropics.

Cerium↗
PubMed1989

A sensitive method for the determination of Th in body fluids.

A method involving neutron activation followed by simple radiochemical separation was developed and applied to determine the concentrations of Th in blood serum and urine. The method is sufficiently sensitive to detect 0.025 ng of 232Th. The average concentration of Th found in the blood serum and urine of subjects from normal environments is 7.9 ng L-1 and 2.7 ng L-1, respectively.

Humans↗
PubMed1986

Daily intake of thorium by an Indian urban population.

Thorium intake by an urban group (Bombay) has been estimated using neutron activation followed by simple chemical separation. Daily intake of thorium via all the three sources: food, water and air, is reported in this paper. The major contribution of thorium to intake is through food (2.0 micrograms), followed by water (0.02 microgram) and air (0.02 microgram). The individual food ingredients such as cereals, pulses, vegetables, milk, etc. were also analysed for their thorium content. The cereals were found to contribute most to the daily intake.

Environmental Monitoring↗
PubMed1986

A geochemical basis for endomyocardial fibrosis.

In a search for geochemical factors that could play a role in the pathogenesis of tropical endomyocardial fibrosis, endomyocardial tissue samples obtained from patients at necropsy or operation were analysed for major elements present in laterite and monazite, which are important soil constituents of Kerala State of India. Atomic absorption spectrophotometry was used for detecting iron, silicon, aluminium, zinc, magnesium, calcium, sodium, potassium, and manganese and neutron activation analysis for thorium. Compared with control samples from victims of fatal accidents, an excess of thorium, sodium, and calcium and a deficiency of magnesium were present in samples from patients. It has been shown earlier that the staple diets of people in Kerala have high concentrations of thorium, and these data show that thorium can become concentrated in cardiac tissues. It is speculated that thorium excess in conjunction with magnesium deficiency may play a role in the causation of tropical endomyocardial fibrosis.

Endomyocardial Fibrosis↗