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  • 1995-1999  (11)
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Material
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Year
  • 1
    Electronic Resource
    Electronic Resource
    Comparison of whole blood, plasma and nails as monitors for the dietary intake of selenium (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 29-34 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The measurement of dietary selenium intake in a free-living population using dietary recall techniques has been shown to be spurious. Consequently, in our laboratory, we have focused on the development of biologic monitors such as blood, nails, hair and urine. In this paper, we report on the neutron activation analysis of whole blood, plasma and nail specimens collected from 285 Caucasian subjects, all permanent residents of Hawaii, participating in a malignant melanoma trial. Correlations between monitors are presented and discussed in the context of selenium determinants and integration of selenium intake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386313
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of an enriched selenium-76 supplement on dietary monitors and glutathione peroxidase activity (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 39-45 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The objective of this study was to determine if a stable enriched tracer of Se-76 could be used to establish the delay time between a dietary intake of selenium and its appearance in various matrices. Selenium, an essential trace element, has been investigated at the Missouri University Research Reactor (MURR) for several years. Several matrices have been studied to determine selenium status in humans; these include fingernails, toenails, blood, hair, and urine. A cohort of five women and seven men was utilized for this study. Each subject ingested selenium supplements which were enriched in Se-76 (96.48%). Fingernails, toenails, whole blood, and blood sera were collected as biochemical indicators. Selenium concentrations and glutathione peroxidase activities were determined in blood sera and whole blood to monitor the effect of the selenium supplement in these matrices. Selenium concentrations were determined in fingernails and toenails prior to supplementation and for several months afterward to determine the delay time for the appearance of selenium. The effects of the selenium supplement on the selenium concentrations of the fingernails, toenails, whole blood, and blood sera and the effect of the supplement on glutathione peroxidase activity will be reported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386315
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Variability in the distribution of selenium in healthy heart tissue measured by neutron activation analysis (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 57b 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Chronic dietary deficiency of selenium has been shown to be associated with degenerative heart disease in production animals in the U.S. and in the human in parts of China. In the latter, subjects in the endemic areas suffer high rates of a cardiomyopathy known as Keshan's Disease which is normally fatal in early adulthood and can be prevented, or reversed in its early stages, via selenium supplementation. Selenium, as the active moiety in the enzyme glutathione peroxidase, protects against oxidative attack of cell membranes by peroxides formed during normal metabolism. In this study, we investigated the distribution of selenium in healthy porcine and bovine heart tissue freshly collected at slaughter. The whole heart was perfused with DI water and carefully de-fatted. Representative samples of left and right atria and ventricles and the interventricular septum were collected, lyophilized and homogenized prior to preparing replicate samples for analysis. Replicates were analyzed for selenium via an INAA scheme employing a 5, 15 and 25 second irradiation (φth = 8·1013 n·cm−2·s−1), decay and real-time count (77mSe,T 1/2=17.4 s), respectively, using high-resolution gamma-ray spectroscopy with Westphal pulse pile-up correction. Selenium distribution will be discussed relative to differentiated function and oxygenation of the specific tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386318
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  • 4
    Electronic Resource
    Electronic Resource
    The study of human nails as an intake monitor for arsenic using neutron activation analysis (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 51-57 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Arsenic is toxic to humans with the lethal dose being approximately 1 mg/kg/day. At much lower long-term exposures, arsenic is hypothesized to increase the risk of certain cancers. We have developed an irradiation position for the neutron activation analysis (NAA) of nail specimens for arsenic, in support of a case-control study involving New Hampshire residents consuming well water above the EPA Safe Drinking Water Standard of 0.050 ppm. Arsenic is bound to nail keratin through sulfhydryl groups proportional to intake providing a convenient means of integrating arsenic intake in population-based studies. Our objective was to develop the necessary facilities and procedures by which relatively small samples (i.e. 20 to 100 mg) could be accurately analyzed for arsenic, so that affordable nutritional epidemiology investigations, requiring large numbers of samples (〉1000 in this case), could be undertaken. A high-flux reflector position, with minimal axial variation throughout the fuel cycle, suitable for pneumatic-tube irradiations, was characterized by measurement of the neutron flux distribution (thermal and epithermal) within the irradiation capsule over time. Results from application of the method to a case-control study of basal and squamous cell skin cancer will be presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386317
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  • 5
    Electronic Resource
    Electronic Resource
    Longitudinal study of iodine in market milk and infant formula via epiboron neutron activation analysis (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 65-69 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Iodine is an essential nutrient in the human diet. Its primary role is expressed as a component of thyroxine (T4) and the corresponding deiodinated triiodothyronine (T3) hormones produced by the thyroid as part of the system that regulates growth, mental development and metabolism. The recommended daily allowance (RDA) for iodine ranges from 50 μg/day for infants to 150 μg/day for adults. Reports over the last 15 years have indicated that the U.S. diet provides 2 to 7 times the iodine RDA and that dairy products typically provide 20 to 60 percent of the dietary iodine intake. Measurements of iodine in dietary components and composites reported in FDA studies have been done calorimetrically. These studies have, according to the authors, both under reports (by up to −50%) and over reports (by up to +80%) the iodine, depending on food type, compared to a radiochemical NAA reference method. Milk is typically under reported by −20%. The objective of this study was to utilize epiboron neutron activation analysis (EBNAA) to study the iodine concentrations, and seasonal variations of iodine, and market milk and infant formula, collected 15 years apart, in comparison with the Food and Drug Administration (FDA) market-basket reports.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386319
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  • 6
    Electronic Resource
    Electronic Resource
    Longitudinal study of iodine in toenails following IV administration of an iodine-containing contrast agent (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 71-77 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The literature on the relationship between diet and thyroid cancer (TC) risk and the higher incidence of TC among Asian immigrants to the US compared to second and third generation subgroups has prompted epidemiologists to hypothesize that increased levels of iodine consumption may be associated with TC risk, particularly among persons with a history of clinical or subclinical thyroid dysfunction. At the University of Missouri Research Reactor (MURR), we have applied epiboron neutron activation analysis to investigate human nails as a dietary monitor for iodine. Preliminary studies have indicated a positive correlation between dietary iodine intake and the concentration of iodine in toenails. However, these studies are confounded by high iodine levels (up to 30 ppm) in approximately 5% of the nails studied. We hypothesize that, in the subjects we have studied, the high iodine levels may be due to iodine-containing medications, in particular contrast-agents containing iopamidol. This paper will report on longitudinal studies using contrast agent subjects who were followed-up for almost two years compared to a longitudinal control and a population mean. Based on this study, we suggest that iodine-containing contrast agents contaminate nail samples via non-specific binding in the short term followed by incorporation in the nail as a result of absorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386320
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Investigation of the appearance of supplemental enriched Se-76 using the human nail as a dietary monitor (1995)
    Springer
    Journal of radioanalytical and nuclear chemistry 195 (1995), S. 97-108 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract The principal objective of this study was to determine if the use of a stable enriched tracer of Se-76 could be used to determine the delay time between a dietary intake of selenium and its appearance in fingernails and toenails. Selenium is an essential trace element in human nutrition. It has been studied at the Missouri University Research Reactor (MURR) for the past 15 years using an Instrumental Neutron Activation Analysis (INAA) technique. The principal route of human exposure to selenium is through the diet. Selenium concentrations of nails, blood, hair, and urine have been used as indicators of dietary selenium intake. In this study, a cohort consisting of seven men and five women ingested three selenium supplements of 150 μg each over a three day period. The selenium was enriched in Se-76 (96.48%) and ingested as selenite in orange juice following an overnight fast. Fingernails and toenails were collected prior to the selenium supplementation and for several months afterward to be used as biochemical indicators. The peak76Se concentration in the fingernails and toenails occurred at 19–23 and 16–32 weeks after supplementation, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02036478
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  • 8
    Electronic Resource
    Electronic Resource
    The determination of48Ca,46Ca, and44Ca by chemical and radiochemical neutron activation analysis (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 113-119 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A chemical and radiochemical neutron activation analysis (CNAA/RNAA) method has been developed for the determination of three calcium isotopes (48Ca,46Ca, and44Ca) in a single sample derived from urine. This method was developed in support of clinical research using a dual enriched stable isotope methodology to study bone mineralization in premature infants, juvenile rheumatoid arthritics, and cystic fibrosis. In these studies, one enriched isotope of calcium is administered orally, and one is administered intravenously. By making determinations of three isotopes (two enriched, one unenriched) within the same sample, the perturbation from natural isotopic ratios can be determined and used to calculate true absorption of calcium. In our method,48Ca is determined via the48Ca(n,γ)49Ca reaction and 3084 keV gamma-ray,46Ca via the46Ca(n,γ)47Ca reaction and 1296 keV gamma-ray, and44Ca via the44Ca(n,γ)45Ca reaction and 256 keV (max) beta-particle. A pair of chemical separation steps are employed to separate calcium from urine as calcium oxalate with a yield in the range of 80–90%, and a radiochemical step is employed prior to the measurement of45Ca to remove interfering radionuclides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386327
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    Paper (German National Licenses)
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  • 9
    Electronic Resource
    Electronic Resource
    Whole body analysis of the knockout gene mouse model for cystic fibrosis using thermal and fast neutron activation analysis (1998)
    Springer
    Journal of radioanalytical and nuclear chemistry 236 (1998), S. 107-112 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A genetically engineered “knockout gene” mouse model for human cystic fibrosis (CF) has been utilized to study bone mineralization. In CF, the so-called cystic fibrosis transmembrane conductance regulator (CFTR) protein, a chloride ion channel, is either absent or defective. To produce the animal model the murine CFTR gene has been inactivated producing CF symptoms in the homozygotic progeny. CF results in abnormal intestinal absorption of minerals and nutrients which presumably results in substandard bone mineralization. The objective of this study was to determine the feasibility of using whole-body thermal and fast neutron activation analysis to determine mineral and trace-element differences between homozygote controls (+/+) and CF (−/−), murine siblings. Gender-matched juvenile +/+ and −/− litter mates were lyophilized and placed in a BN capsule to reduce thermal-neutron activation and irradiated for 10 seconds at φfast ≈ 1·1013 n·cm−2·s−1 using the MURR pneumatic-tube facility. Phosphorus was measured via the31P15(n,α)28Al13 reaction. After several days decay, the whole-body specimens were re-irradiated in the same facility, but without thermal-neutron shielding, for 5 seconds and the gamma-ray spectrum was recorded at two different decay periods allowing measurement of77mSe,24Na,27Mg,38Cl,42K,49Ca,56Mn,66Cu and80Br from the corresponding radiative-capture reactions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02386326
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  • 10
    Electronic Resource
    Electronic Resource
    Determination of iodine in human nails via epithermal neutron activation analysis (1995)
    Springer
    Journal of radioanalytical and nuclear chemistry 195 (1995), S. 21-30 
    Details
    ISSN: 1588-2780
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract An epithermal instrumental neutron activation analysis (EINAA) method, using a boron nitride irradiation capsule compatible with use in the University of Missouri Research Reactor pneumatic-tube irradiation facility, has been developed for the analysis of iodine in human nails. The principal objective was to determine if the nail could be used as a means of monitoring dietary intake of iodine. The EINAA method was used to analyze nails from subjects having iodine intakes that could be qualitatively differentiated. Iodine concentrations in nails from these subjects were positively correlated with apparent iodine intake.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02036469
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    Paper (German National Licenses)
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