Call number: LD2668 .T4 1934 W61

Seven prospective biological indicators of systemic toxicity were examined at time points ranging from 15 minutes to 24 hours using male Sprague-Dawley rats, B6C3F1 mice, Golden-Syrian hamsters and Hartley guinea pigs following intraperitoneal dosing with 0.1 mg/kg and 1.0 mg/kg sodium arsenite. Rats and mice were also dosed with 1.0 mg/kg sodium arsenate. Pyruvate dehydrogenase (PDH) activity was significantly depressed at early time points in mice, hamsters and guinea pigs and at later time points in rats dosed with arsenic (III). Rats and mice dosed with arsenic (V) also exhibited PDH depression at early time points. Uroporphyrin and coproporphyrin excretion was elevated in mice following arsenic (III) dosing. Coproporphyrin excretion was elevated in rats following arsenic (V) dosing. Blood glucose, creatinine, urea nitrogen and creatinine were unchanged by arsenic dosing. Based upon the amount and types of biological responses observed, the mouse appears to be the most sensitive animal model for the further study of arsenic toxicity.

published_or_final_version / abstract / Medicine / Master / Master of Philosophy

Recorded use of pesticides in the conservation of artifacts dates back to the 16th century. Museums today are faced with a tremendous task of identification and remediation of pesticides from artifacts in order to protect museum workers and the general public. In addition, artifacts are being repatriated by Native American tribes for use in cultural ceremonies which may subject the practitioner to health risks. Arsenic and mercury salts are among the pesticides that were used that are highly persistent and toxic. The primary challenge lies in removing these hazardous and persistent metals without damaging the materials or pigments on the objects.Concentrated aqueous alpha-lipoic acid solutions were developed for removing arsenic and mercury pesticides from materials commonly used in museum artifacts. The alpha-lipoic acid solutions were reduced using natural sunlight or laboratory ultraviolet lamps to enhance the binding of arsenic. The solubility of alpha-lipoic acid in various organic and inorganic solutions was determined and environmental parameters that impact the reduction and solubility, such as pH and temperature, were examined. The kinetics of the reaction of arsenic (III) with reduced lipoic acid was examined by varying the reduced lipoic acid, base and arsenic concentration as well as temperature and stirring conditions. The results indicated that the reaction occurs at a moderate rate primarily within 8 seconds in air. The reaction is chemically rate limited enhanced at higher temperatures and lower pH. Aerobic conditions significantly decreased the extent of the reaction with increased stirring rate. This impact was minimized by using a nitrogen environment or by limiting agitation during the reaction step.The methods developed were capable of removing up to 1000 µg/cm2 arsenic (of sodium arsenite) from simulated artifacts to levels near the lower detection limit of the X-ray Fluorescence Spectrometer (1 µg/cm2) without leaving detectable residues according to Attenuated Total-Reflection Fourier Transform Infrared Spectroscopy. Similar results were achieved in removing mercury (of mercuric chloride) from non-sulfur containing materials; however, the solutions and processes developed were not capable of removing mercury from sulfur-containing materials such as wool and feathers.

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This thesis describes a series of experiments, firstly into mammalian arsenic urinary metabolites and secondly into the use of phospholipase enzymes as a tool to assist in the characterisation of lipids extracted from the seaweed, <i>Laminaria digitata</i>. HPLC-ICP-MS has been used as the principal analytical instrument, often coupled with ES-MS. The ICP-MS. Provides a ‘hard’ ionisation process and yields data specific to arsenic. ES-MS (electrospray mass spectrometry) is a ‘soft’ ionisation technique that allows analysis of the intact molecules. Analysis of the urine from Scottish Blackface sheep that had been the subjects of a feeding trial in which the sheep routinely ate <i>Laminaria</i> <i>digitata</i> as part of their normal diet revealed the presence of the short chain fatty acids, dimethylarsenopropionic acid and dimethylarsenobutanoic acid. These had previously only been seen in the urine of human volunteers following ingestion of cod liver oil. Further controlled feeding trial experiments were performed in which cod liver oil, <i>Laminaria digitata</i> and aqueous extract of <i>Laminaria digitata</i> was ingested by human volunteers. Similarities and differences in the arsenic urinary metabolites resulting from the different feeding trial regimes were investigated. The continual presence of arsenobetaine in the urine produced by the volunteers, including the control samples, raised questions concerning the accepted retention time of arsenobetaine in the body that were answered by performing another feeding trial, the results of which have been published. Phospholipase D, C, and A2 were used to cleave arsenic containing phospholipids extracted from freeze dried <i>Laminaria digitata</i>. Some valuable information was gained and the technique shows great promise for future study.