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Abstract  

A procedure developed for separating and quantifying non protein and protein fractions of aluminum species in urine was applied to four consecutive 24 hr collections of five healthy subjects. The total Al content of urine was determined by a chemical neutron activation analysis technique reported elsewhere. Results from the analysis of all subjects indicate that the majority of aluminum is bound to protein (>88%) with minor fractions as citrate complexes. These data are comparable with other speciation experiments with blood plasma indicating 90% of the aluminum was bound to plasma proteins.

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Abstract  

The radiochemistry of aluminum was reviewed for the Sub-Committee on Radiochemistry, National Research Council of the United States National Academy of Sciences. The focus of the review is on nuclear and instrumental methods for analysis of Al in biological and environmental samples. Aluminum is a neurotoxin. Continuing controversy about environmental Al and Alzheimer's Disease has motivated development of ultra-sensitive and precise analysis of samples, since the first review on the radiochemistry of aluminum in 1961. Examples and selected procedures of particular interest to radiochemists are given. Selected topics include tracer applications of28Al and29Al; and AMS for determination of26Al relative to questions asked by cosmochemists and geochemists. Extensive tables provide physical data, stability constants of Al complexes, comparison of analytical methods of analysis of biological samples, and a compilation of results obtained by various techniques for Standard Reference Materials. The literature search was through August, 1995.

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Abstract  

This study determined trimethylselenonium ion [TMSe, (CH3)3Se+] and total organic selenium cationic species urinary excretion values for healthy human subjects and Sprague-Dawley rats fed regular diets. The only source of TMSe was from the endogenous selenium body pool. Total selenium concentration, in urine was determined by instrumental neutron activation analysis. TMSe and total selenium cationic species concentrations and percent of total selenium urine excretion were determined by chemical neutron activation analysis and coupled anion-cation exchange chromatography and anion-exchange chromatography, respectively. Within experimental error, mean values for TMSe and cationic species as percent selenium were comparable for both human subjects and Sprague-Dawley rats. This study suggested that TMSe excreted in urine by healthy human subjects and Sprague-Dawley rats fed a normal diet is not a minor but a general metabolite of selenium ingested in a normal diet.

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Abstract  

A radiometric recoil130Im+130I atom tracer technique was developed for determining iodide ionbiomolecule association in liquid and frozen aqueous solutions of slightly soluble biomolecule solutes. It was found that the iodide ion associates with 5-iodouracil and 3-iodo-L-tyrosine, but exhibits no association with uracil and 3,5-diiodo-L-tyrosine.

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Abstract  

Mercury, a known neurotoxin, has been implicated in the etiology and pathogenesis of such disease states as Alzheimer's and Parkinson's diseases. There is concern that the exposure to mercury vapor released from dental amalgam restorations is a potential health hazard. Measurement of mercury concentrations in blood or urine may be useful in diagnosis of mercury poisoning and in assessing the extent of exposure. This study describes the optimization of pre-neutron activation analysis procedures such as sampling, selection of irradiation and counting vials and acid digestion in order to minimize mercury loss via volatilization and/or permeation through containers. Therefore, the determination of mercury can be complicated by these potential losses. In the optimized procedure 20 mL of urine was spiked with three different concentrations of mercury, digested with concentrated nitric acid, and placed in polypropylene vials for irradiation and counting. Analysis was performed by subtracting the Se-75 photopeak contribution to the 279 keV Hg-203 photopeak and applying the method of standard additions. Urinary mercury concentrations in normal human subjects were determined to be of the order of 10 ng/mL.

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Abstract  

Trinethylselenonium (TMSe) ion was separated by dual-column ion-exchange chromatography and assayed by neutron activation analysis. The TMSe content of the selenium in human urine was found to be (14±2)%, consistent with literature values. An altemate, published, multi-step procedure employing Reineckate precipitation followed by decomposition/volatilization conversion of selenium into dimethylselenide, perchloric acid digestion into selenite and subsequent analysis employing inductively coupled plasma mass spectrometry (ICP-MS) was evaluated. A maximum recovery of TMSe was estimated at 32%. It has been suggested that losses in each step of a multi-step procedure yield low recoveries as reported in the literature.

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Abstract  

A new and simple method for the labelling of halogenated organic molecules and biomolecules is described. Dilute aqueous solutions of the halogenated molecule are irradiated with neutrons in the frozen state. The labelling yields are generally high for the 18 compounds investigated and constant over a large concentration range. The major observed labelled organic product is the radiohalogen labelled parent molecule with the halogen at its original site. Unlike neutron-irradiated liquid aqueous solutions of the same compounds no radiation damage to the molecules is observed for the irradiation times employed.

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Abstract  

A destructive neutron activation analysis procedure was developed for determining trace aluminum content in bone. It was found that soil contamination can influence the aluninum bone levels in prehistoric bone specimens. These maximum aluninum content values for prehistoric bone are larger than those of modern bone and comparable to aluminum levels present in bone from renal patients.

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Abstract  

A method is described for determination of vanadium in biological tissues. This method consists of a wet digestion of the tissue with nitric acid followed by anion exchange chromatography, neutron irradiation, and radioassay. The chromatographic separation will allow the decontamination of vanadium from radioactivatable sodium and chlorine which are present in large quantities in biological tissues. The validity of the method is evaluated by employing NBS-SRM 157 and 157a Bovine Liver employing the method of standard additions. The method is successfully applied to human, cow and rat liver specimens. The detection limit of the method is one ppb.

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Abstract  

Vanadium in serum was investigated by pre-irradiation chemistry neutron activation analysis employing anion exchange chromatography and post-irradiation neutron activation employing solvent extraction techniques. From a comparison of these techniques it is concluded that vanadium is present in human serum in the sub-ppb range.

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