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Biomedical subjects

R D Taylor

Publications and source records attributed to R D Taylor.

49 records · Page 3Linked to original sources

Elimination of the hazards from hazardous wastes.

The "hazard" associated with a waste essentially controls the overall engineering approach to finding suitable alternatives for solving potential disposal problems. It should be recognized that all factors affecting environmental equilibrium must be considered, including product sales, process design, financing, pre- and end-of-pipe treatment, residuals management, and ultimate bioaccumulation of residuals. To meet this challenge, a systems approach to waste treatment and residuals disposal provides a logical approach, but this management concept requires a thorough understanding of the important physical and chemical aspects of the problem, as well as many social implications of the resulting decisions. Thus waste management within a plant necessarily involves process control, pretreatment and end-of-pipe treatment. Further, it follows that residuals management from a disposal point-of-view must ultimately embrace what is called the "multi-barrier concept." In essence, hazard elimination occurs in varying degrees during each phase of a properly engineered system.

Adsorption↗

Spontaneous drainage of a large cystic tumor.

A case is described of a 58 year old male who presented with a large mass on the left side of the abdomen which was found to be cystic by ultrasound. A presumptive diagnosis of pancreatic pseudocyst was made. Shortly thereafter, the mass drained spontaneously further suggesting this diagnosis. At surgery a month later, however, the mass was found to be a metastic leiomyosarcoma with cystic degeneration that had eroded into the gastric wall. This case serves to illustrate that cystic abdominal masses, even ones that drain spontaneously into the gastrointestinal tract, may not be pancreatic pseudocysts.

Diagnosis, Differential↗

Diagnosis of hepatic hemangioma using multiple-radionuclide and ultrasound techniques.

Two cases of heptatic hemangioma are reported in which multiple-radionuclide and ultrasound techniques were combined in the diagnostic process. Blood pool imaging rather than perfusion imaging proved to be the most definitive diagnostic procedure. The application of radionuclide and ultrasound studies in the differential diagnosis of focal lesions of the liver is discussed.

Adult↗

Radionuclide scanning in the evaluation of Kaposi sarcoma.

A patient with Kaposi sarcoma showed increased uptake of sodium pertechnetate Tc 99m over both clinically evident and occult regions of involvement. The clinically negative but scan-positive regions showed pathologic lesions by biopsy. Gallium citrate Ga 67 and bleomycin sulfate labeled with indium 111 (111In) did not concentrate in the lesions, which suggest that Kaposi sarcoma, despite its resemblance to lymphoma, differs from lymphoma substantially with reference to raionuclide uptake. This report confirms that sodium pertechnetate Tc 99m is the most sensitive agent for diagnostic and therapeutic evaluation of patients with Kaposi sarcoma and suggests taht gallium citrate Ga 67 or bleomycin 111In may be useful in the differentiation of Kaposi sarcoma from lymphoma.

Animals↗

Preparation of mixtures of humidified air with CO, SO2, NO2, NH3, NH2CH3, Cl2, and HCl to measure respirator cartridge and canister service life.

Four systems have been fabricated to measure the effective service life of respirator cartridges and canisters. The four systems employ carbon monoxide, sulfur dioxide/nitrogen dioxide, ammonia/methylamine, and chlorine/hydrogen chloride as contaminants. Each system produces test concentrations in the low percentage range (typically 0.05 to 3.0%) at flow rates of 32 and 64 liters/min and at relative humidities between 20 and 95%. Suitable anlyzers have been provided to measure the downstream concentration from 1 to 500 ppm as a function of time. Holders have been designed to accommodate the wide size variation of commercially available cartridges and canisters.

Air↗

Disulfiram as a radiation modifier.

The radiation modifying effect and toxicity of tetraethylthiuram disulfide (disulfiram) have been studied. Disulfiram (DSM) inhibits aldehyde dehydrogenase, dopamine-beta-oxygenase, microsomal mixed-function oxidases and cytochrome P-450 enzymes. It is widely used for aversion therapy in alcoholism. Disulfiram also inhibits tumor formation by several known carcinogens. A biphasic toxicity pattern of DSM is reported in the L-929 mouse fibroblast culture system. Disulfiram is 100 percent toxic at 2 X 10(-7) M (0.05 micrograms per ml), 23 percent toxic at 3 X 10(-7) M (0.1 microgram per ml), and 100 percent toxic again at 3.4 X 10(-6) M (1.0 microgram per ml). The pattern is similar to the biphasic toxicity pattern of DMS's major metabolite, sodium diethyldithiocarbamate (DTC). Reports of both radiation protection and radiation enhancement by DTC exist. Previously, a radioprotective effect by 2 X 10(-6) M DTC (dose modifying factor = 1.26) has been demonstrated in the L-929 cell system. To date, no radiation modifying properties of DSM have been reported. Our investigation of DSM as a radiation modifier at 3 X 10(-7) M (0.1 microgram per ml) did not show significant improvement in survival of irradiated cells treated with DSM relative to the irradiated control group, as determined by absence of a difference in the Do of the two groups. Considering DSM's close structural relationship to DTC, it is possible that DSM may exhibit a radioprotective effect when applied in a different concentration than what was used in our research.

Animals↗