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Biomedical subjects

A Chatt

Publications and source records attributed to A Chatt.

13 recordsLinked to original sources
PubMed1999

Correlation between total and EDTA/DTPA-extractable trace elements in soil and wheat.

Wheat and wheat products are more important sources of energy and nutrients in diets of people in many cultures compared to other foods. The daily consumption of wheat is about 200 g/d/person in Western Europe and North America. On the other hand, 400-450 g of wheat and wheat products are consumed daily by average Turkish people. Wheat samples collected from the Iskenderun region in 1995 and 1996 and Ankara and Istanbul regions in 1995 were analyzed for their trace element content by instrumental neutron activation analysis (INAA). In addition, 13 soil samples were collected from the Iskenderun region in 1996. Total soil samples were analyzed by INAA and atomic absorption spectrometry (AAS), EDTA-extractable elements by INAA, and DTPA-extractable elements by AAS. Correlation analysis and enrichment factor calculations were applied to the trace element results. In wheat samples, a strong correlation was found between the elements such as Sc, La, Sm, Rb, and K whose main source is soil. The concentration of Se appeared to show larger variations among different regions. No significant correlation was observed for elements such as As and Se whose main sources in the atmosphere are anthropogenic activities.

Edetic Acid↗
PubMed1999

Spatial distribution of extractable organohalogens in northern pink shrimp in the north Atlantic.

Extractable organohalogens (EOX) are organic compounds that contain chlorine, bromine and/or iodine, which can be separated from the matrix by liquid/liquid or liquid/solid extraction. A combination of instrumental neutron activation analysis (INAA) and solvent extraction methods has been developed for the determination of EOX from the shrimp Pandalus borealis. Levels of EOX were evaluated for spatial trends for shrimp caught in several areas off the Labrador coast, off the coast of Nova Scotia, and off the coast of Maine. Muscle contained 1.09-6.05 micrograms EOCl/g tissue and 105-498 micrograms extractable organochlorine (EOCl)/g lipid; 0.0607-0.288 microgram extractable organobromine (EOB)r/g tissue and 4.74-10.5 micrograms EOBr/g lipid; and 0.014-0.048 microgram extractable organoiodine (EOI)/g tissue and 1.03-1.76 micrograms EOI/g lipid, respectively. The levels of EOCl in roe were 1.60-12.34 micrograms/g tissue and 39.0-146 micrograms/g lipid. In roe, the EOBr levels were 0.707-1.03 micrograms/g tissue and 6.96-13.5 micrograms/g lipid; and EOI levels were 0.123-0.349 microgram/g tissue and 1.42-4.11 micrograms/g lipid. The EOCl, EOBr, and EOI levels in roe increased noticeably from north to south along the coast of Labrador. Samples taken from the coast of Maine and from Canso Hole were typically higher in EOCl levels than those taken from Labrador. The results for EOBr and EOI were in the same range as those from Labrador.

Animals↗
PubMed1999

Determination of selenium in Canadian food items by cyclic instrumental neutron activation analysis.

Instrumental neutron activation analysis (INAA) and pseudocyclic INAA (PCINAA) have been used to determine the selenium content of a variety of Canadian food items. Use of the 162-keV gamma ray of short-lived 77mSe in INAA allowed relatively simple and rapid determinations and was suitable for many of the foods. PCINAA was found to give lower detection limits and was used for the low-selenium food samples. Both internal and external quality assessments were used to evaluate and assure the accuracy and precision of the methods developed.

Food Analysis↗
PubMed1997

Extractable organohalogens in tissues of beluga whales from the Canadian Arctic and the St. Lawrence estuary.

Samples of blubber, brain, kidney, liver, and muscle of individual beluga whales were extracted and analyzed for extractable organic Cl (EOCl), Br (EOBr), and I (EOI) by neutron activation analysis. The highest levels of EOCl (554 microg g(-1) lipid) were found in the kidney of Arctic beluga and the lowest (24 microg g(-1) lipid) in the blubber. Levels in brain and liver lipids were on average of equal magnitude. The unequal distribution of EOCl in tissue lipids is in marked contrast to the equal distribution, in lipid, demonstrated for organochlorines such as DDTs and PCBs by a number of investigations. The distribution of brominated (EOBr) and iodinated (EOI) compounds was similar and markedly different from that of EOCl. The tissue distribution of EOCl seems to be related to the proportion to polar lipids in the tissues. Beluga from St. Lawrence had significantly higher brain EOCl levels than the Arctic samples whereas the levels of EOCl in liver and kidney were higher in the Arctic whales.

Journal Article↗
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

Determination of nanogram amounts of iodine in foods by radiochemical neutron activation analysis.

Three different neutron activation analysis methods have been developed for the determination of ppb levels of iodine in food samples. The methods are based on the separation of iodine using (i) toluene extraction followed by bismuth sulfide coprecipitation; (ii) bismuth sulfide coprecipitation followed by radiochemical purification with palladium iodide; and (iii) radiochemical isolation by bismuth sulfide coprecipitation. The accuracy of these methods was evaluated by analysing replicate samples of reference materials. The measured values of iodine in A-11 Milk Powder, H-4 Animal Muscle and H-9 Mixed Human Diet from the International Atomic Energy Agency (IAEA) are statistically indistinguishable from the IAEA recommended values, and those for the Standard Reference Materials 1571 Orchard Leaves and 1577 Bovine Liver from the National Institute of Standards and Technology (NIST) are in good agreement with the NIST information values. The precision, in terms of relative standard deviation, is 5% at 50-100 ppb and 10% at 5-20 ppb levels of iodine. The absolute detection limits of these methods vary between 0.5 and 10 ng of iodine. All three methods were used to measure the iodine content of several food samples. The method involving bismuth sulfide coprecipitation followed by radiochemical purification provides the best detection limit and highest precision.

Food Analysis↗
PubMed1991

Microwave acid digestion and preconcentration neutron activation analysis of biological and diet samples for iodine.

A simple preconcentration neutron activation analysis (PNAA) method has been developed for the determination of low levels of iodine in biological and nutritional materials. The method involves dissolution of the samples by microwave digestion in the presence of acids in closed Teflon bombs and preconcentration of total iodine, after reduction to iodide with hydrazine sulfate, by coprecipitation with bismuth sulfide. The effects of different factors such as acidity, time for complete precipitation, and concentrations of bismuth, sulfide, and diverse ions on the quantitative recovery of iodide have been studied. The absolute detection limit of the PNAA method is 5 ng of iodine. Precision of measurement, expressed in terms of relative standard deviation, is about 5% at 100 ppb and 10% at 20 ppb levels of iodine. The PNAA method has been applied to several biological reference materials and total diet samples.

Food Analysis↗
PubMedDate not supplied

Studies on zinc- and cadmium-bound proteins in bovine kidneys by biochemical and neutron activation techniques.

Bovine kidneys were found to contain about 78 ppm Zn and 0.78 ppm Cd. Approximately 45% of Zn and 60% of Cd were present in the cytosol fraction. More than 95% of these two metals were bound to macromolecules. Both Zn- and Cd-protein complexes were observed to be stable between pH 7 and 10.5. Separation and characterization of these proteins were carried out using several chromatographic and electrophoretic techniques in conjunction with instrumental neutron activation analysis (INAA). The results showed the presence of at least four Zn-binding proteins with mol wt greater than 300,000, 260,000, 89,000, and 27,000 and at least three Cd-binding proteins of mol wt greater than 300,000, 32,000, and 13,000.

Animals↗
PubMedDate not supplied

Metabolic deposition of selenium and cadmium into the hair and other tissues of the guinea pig.

To better understand the significance of hair trace-element measurements and their relationships with the trace-element levels in body organs and fluids, a series of controlled animal experiments were conducted in which several trace elements were periodically measured during a 90-day chronic exposure to selenium and cadmium. Chronic selenium exposure appeared to be reflected by elevated selenium levels in the hair, kidneys, and liver. Chronic cadmium exposure, although reflected by kidney and liver elevation, appeared not to be reflected by corresponding increases in its concentration in the hair.

Animals↗
PubMedDate not supplied

Determination of selenium in duplicate diets of residents of Pinhel, Portugal, by neutron activation.

A rapid cyclic instrumental neutron activation analysis (CINAA) method has been used to determine the selenium content of 27 duplicate diet samples from each of the 27 districts surrounding Pinhel, Portugal. The accuracy and precision of the CINAA method have been evaluated by analyzing certified reference materials and observed to be within +/- 5-10% for samples containing at least 40 ppb of selenium. The detection limit has been found to vary between 26-42 ppb selenium depending on the sample composition. The average daily dietary intake has been calculated as 37 micrograms of selenium per day.

Diet↗
PubMedDate not supplied

Total organochlorine content of fish from the Great Lakes.

Residues of polychlorinated biphenyls (PCBs) and organochlorine pesticides were determined in several species of commercial fish from the Great Lakes and compared to the total organic chlorine determined by neutron activation analysis. The mean organochlorine contents ranged from 44 to 138 ppm (lipid basis) and were 5 to 72 times higher than the contents of PCBs and organochlorine pesticides. Marine fish also contained a large proportion of unidentified organic chlorine. The unknown material in the Great Lakes fish was found to chromatograph with the high molecular weight lipid fraction by gel permeation chromatography.

Animals↗