Biology ETDs

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The use of nuclear generated power increases the risk that human accidental exposure to radionuclides will occur. Chelation therapy has been used to remove internally deposited radionuclides primarily by intravenous injection of diethylenetriaminepentaacetic acid (DTPA). Recently, inhalation of aerosolized DTPA has been shown to be both a convenient and effective means of treatment. Inhalation of aerosolized OTPA through the nose and mouth results in a significant deposition in the nasopharyngeal region of the respiratory tract. This study was designed to determine the fate of OTPA deposited in the nasopharyngeal region of the respiratory tract of rats and Beagle dogs, particularly as it related to absorption of OTPA into the general circulation.

Rats and Beagle dogs were administered 111InDTPA by injection, gavage or inhalation. Injection studies mimicked complete absorption of DTPA into the circulatory system. Gavage experiments provided data on the gastrointestinal absorption of OTPA. Inhalation studies involved the exposure of animals to two 111 InDTPA aerosols with mean activity median aerodynamic diameters of 0.68 um and 10.4 um, respectively. The latter aerosol resulted essentially in total nasal deposition while the former was deposited throughout upper and lower regions of the respiratory tracts of each species.

Significant quantities of DTPA were absorbed from the nasopharyngeal regions of both rats and dogs. Greater amounts of DTPA were absorbed by the rats (68%) relative to the dogs (23%). Absorption of DTPA entering the gastrointestinal tract was 4% and 8% for rats and dogs, respectively. After exposure to the small particle OTPA aerosol, neither rats nor dogs showed retention of DTPA in the lung at sacrifice indicating rapid and complete absorption of DTPA from the pulmonary region of the respiratory tract.



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Level of Degree


Department Name

UNM Biology Department

First Committee Member (Chair)

Roger O. McClellan

Second Committee Member

Marvin L. Riedesel

Third Committee Member

Gordon Verle Johnson

Fourth Committee Member

Bruce A. Muggenburg

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Biology Commons