Anthony A. Thomas

A Colorimetric Method for the Determination of Hydrazine and Monomethylhydrazine in Blood

Abstract A simple procedure is described for measuring microgram amounts of hydrazine in the blood serum of rats. The procedure, with a minor modification, can be used for measuring microgram amounts of monomethylhydrazine. Calibration ranges of 0.5 to 5.0 μg of hydrazine and 0.5 to 10.0 μg of monomethylhydrazine per milliliter are presented. Data are presented on the dose-blood-level relationship of hydrazine and monomethylhydrazine in rats after intraperitoneal injection. Minimum detectable dose levels were 0.6 mg of hydrazine and 3.0 mg of monomethylhydrazine per kilogram.

Absorption, distribution, and excretion of 1,1-dimethylhydrazine (UDMH)

Abstract The absorption, distribution, and excretion of 1,1-dimethylhydrazine (UDMH) have been studied in rats, rabbits, cats, dogs, and monkeys by use of C 14 -tracer and colorimetric methods. UDMH was rapidly absorbed into the blood regardless of route of administration and was also quite rapidly excreted by the kidneys as evidenced by early high concentrations in both blood and urine. Simultaneous tracer and colorimetric studies indicated that 30–50% of the compound was excreted in its unchanged form in the urine of hydrated cats and dogs in 5 hours. Tracer experiments have shown that UDMH is not preferentially concentrated in the vital organs of the body. Peak concentrations of UDMH in blood are found in 15–60 minutes after injection. The compound was not detectable in the blood of any species after doses of less than 10 mg/kg. Wide variations in individual levels of UDMH in blood with respect to dose and time made it extremely difficult to predict accurately the extent of exposure by examination of blood concentration. The most sensitive indication of exposure to UDMH was the presence of the compound in the urine. Urinary concentrations were found at dose levels which did not produce detectable blood concentrations. The relationships of UDMH blood and urine levels and their correlations with symptomatology have been discussed.

Pharmacology and toxicology of 1, 1-dimethylhydrazine (UDMH).

Abstract UDMH is a missile propellant which has incurred increased usage. The acute intraperitoneal LD50s in the rat, mouse, dog, and monkey were 104, 132, 60-100, and 60-100 mg/kg, respectively. All animals showed clonic-tonic convulsions, and death was by respiratory arrest. Intravenous injection of 1-50 mg/kg UDMH caused no immediate effect on carotid blood pressure, respiration or EKG of the anesthetized dog. UDMH did not effect the pharmacodynamic activity of acetylcholine, histamine, epinephrine, and norepinephrine, nor did it alter the responses caused by faradic stimulation of the peripheral or central end of the cut vagus.

Limits of detection of beryllium in tissues by microemission spectrography.

Abstract The metal beryllium has been successfully and unequivocally demonstrated by microemission spectrography on a semiquantitative basis in tissue sections 50 microns thick. The beryllium was localized in individual pulmonary granulomas in dogs exposed to beryllium. The determination of the lower limit of detection could indicate the threshold level of beryllium in tissue that can induce injury. Beryllium acetylacetonate dissolved in technical-grade xylene was used to prepare a series of working standards. Initial results indicate that as little as 1.48 × 10−12 gm of beryllium is a sample of paraffin weighing about 2.91 × 108 gm has been detected. Similar or greater quantities of beryllium have been demonstrated in similar-size samples of embedded lung tissue from dogs exposed to beryllium.