Wayne V. Kessler

Effects of toluene inhalation on brain biogenic amines in the rat

The effects of toluene exposure on the biogenic amine concentrations in the central nervous system were investigated in the rat. Toluene was administered via inhalation to groups of rats at concentrations of 0, l00, 300, or 1000 ppm. After an 8-h continuous exposure, animals were sacrificed and whole brain concentrations of dopamine (DA), norepinephrine (NE), and 5-hydroxytryptamine (5-HT) were determined. The data indicated a significant increase in whole brain concentrations of DA following the 100-ppm exposure. A regional analysis of DA, NE, and 5-HT concentrations in rats exposed to 1000 ppm of toluene for 8-h indicated a significant increase in DA concentration in the striatum. A significant increase in NE concentrations was detected in the medulla and midbrain while 5-HT concentrations were significantly increase in the cerebellum, medulla, and striatum. The results indicate that toluene action results in elevated concentrations of behaviorally significant neuro-transmitters.

Fetal effects of cadmium in pregnant rats on normal and zinc deficient diets

SummaryThis investigation has shown that not only the extent of fetal resorption and malformation but also the types of malformation seen in rats depend upon the strain used and day of gestation. Furthermore, the effects of zinc deficiency and cadmium administration on the fetus can be at least additive, as was seen for malformations. For fetal resorption, zinc deficiency potentiated the action of cadmium.

Mechanisms of cadmium- and barium-induced adrenal catecholamine release☆

Abstract Different patterns of catecholamine release are produced by perfusion of isolated bovine adrenals with Cd 2+ , Ba 2+ , and Zn 2+ (5 m m ). The action of Zn 2+ is weak but prolonged. The effect of Cd 2+ is slow in onset and prolonged in duration compared to that of Ba 2+ . Neither Cd 2+ nor Ba 2+ increased release of the cytoplasmic enzyme, lactate dehydrogenase. These ions, therefore, do not disrupt adrenomedullary cells to cause catecholamine release. Neither Ba 2+ nor Zn 2+ affected 45 Ca distribution in subcellular fractions of adrenal medulla. Cadmium ion, however, decreased mitochondrial and increased microsomal and supernatant 45 Ca 2+ contents. Mitochondria accumulated relatively large quantities of both cadmium and barium, but chromaffin granules contained twice as much cadmium as barium. Zinc contents were relatively low in all subcellular fractions. It is concluded that Cd 2+ probably releases adrenal amines by mobilizing mitochondrial Ca and possibly by a direct effect on chromaffin granules. Barium ion does not affect the distribution of adrenomedullary cell Ca, but it probably mimics the action of Ca 2+ in evoking catecholamine release. The weak effect of Zn 2+ may be related to limited penetration of cells of adrenal medulla.

Effect of multiple doses of cadmium on glucose metabolism and insulin secretion in the rat.

The effect of multiple doses of cadmium on insulin secretion from the perfused pancreas was studied. In addition, urine and plasma glucose, plasma immunoreactive insulin, and the rate of evolution of respiratory 14CO2 after administration of [UL-14C]d-glucose were determined. The treated groups received two dose levels, 0.25 or 0.50 mg Cd/kg, ip every second day for 70 doses. Multiple doses of 0.50 mg/kg caused an inhibition in the amount of insulin secreted from the perfused pancreas, whereas multiple doses of 0.25 mg/kg caused a partial inhibition that was not statistically significant. With the exception of the plasma insulin concentration in animals receiving multiple doses of 0.50 mg/kg, statistically significant differences in the plasma glucose, plasma insulin, and insulinogenic index were not detected. A high glucose concentration as well as a high concentration of 14C in the urine of treated animals was found. Treated animals expired smaller amounts of 14CO2 than the controls. Animals receiving the higher dose showed significantly lower weights than either the controls or the animals receiving the lower dose, which did not differ significantly from each other.

RELATIONSHIPS BETWEEN PHYSICAL PERFORMANCE ITEMS AND BODY COMPOSITION.

Abstract The purpose of the study is: (a) to determine the relationships between body composition and physical peformance and related items; and (b) to determine whether or not certain physical performance and related items might be useful in estimating body composition in terms of total lean body mass and percent lean body mass as measured by potassium-40 determinations in adult men. Data on 19 physical performance items were obtained from 40 subjects between 21 and 57 years of age. The results are of value to researchers in general and researchers in physical education in particular for estimating gross body composition using certain physical performance items.

Body composition: relative in vivo determinations from potassium-40 measurements.

Measurements of body composition from serial, in vivo determinations of potassium-40 were made on 51 obese human subjects who were placed on a low calorie diet. Weight losses in the group averaged from 12 to 36 pounds. There was no change in potassium content or in lean body weight. Weight loss resulted from the loss of excess body fat.

Placental Transfer and Teratology of Pentachlorophenol in Rats

Pentachloro[U-14C]phenol was administered orally to Charles River CD strain pregnant rats on day 15 of gestation. Concentrations found in the placentas and fetuses up to 32 hr remained very small indicating that the amount that passes through the placental barrier is negligible. Unlabeled compound was administered on days 8, 9, 10, 11, 12, and 13 of gestation. The incidence of resorptions in the treated animals was not significantly greater than that in the controls. Although malformations were observed, the number was minimal and could have been due to the toxic effects of the compound on the maternal rat.

A 2π liquid scintillation counter for determining the radioactivity of large samples including man and animals

Abstract The design and operating characteristics of a 2 π large-volume liquid scintillation counter are described. The counter is used for measuring natural and tracer amounts of added radioactivity in people, animals and large samples. The detector tank, containing more than 90 gal of scintillator solution, is mounted in a horizontal position and is shielded by 6 in. of steel. The tank has a semicircular center well in which the samples are placed. This well is 72 in. long and has a 20-in. diameter. Six 16-in. dia. photomultiplier tubes provide good light collection efficiency. A conveyor system permits rapid and convenient loading and unloading of samples. The counter is currently being used to count Cs 137 and K 40 simultaneously. The counting efficiency for a Cs 137 point-source is 30.5 per cent with an average background of 13,300 counts/ min, and the counting efficiency for a 3.32 kg potassium chloride standard is 18.6 per cent with an average background of 8600 counts/min. The natural K 40 level in humans can be determined with an error of less than 2.5 per cent in a counting time of 4 min.

Radionuclide content of and 222Rn emanation from building materials made from phosphate industry waste products.

The radionuclide content and 222Rn emanation coefficients of selected construction materials were determined. The materials were analyzed for 226Ra, 228Ra and 40K by gamma-ray spectrometry. Mineral wool insulation, which is made from Tennessee phosphate slag, and commonly used insulation, which is made from blast furnace slag, had similar concentrations of these radionuclides. Concrete blocks made with phosphate slag had enhanced 226Ra and 228Ra contents when compared to ordinary concrete block. The mineral wool insulation materials which were examined had emanation coefficients that were a few (2-6) times 10(-3). All other materials had emanation coefficients that ranged from 6 X 10(-4) to 4 X 10(-2).

The pharmacokinetics of inhaled chlorobenzene in the rat

Male rats were exposed for 8 hr/day to 100, 400, or 700 ppm of [14C]chlorobenzene vapor for either 1 or 5 days for the purpose of examining the dose dependency of parameters indicative of the toxicity process and the effect of repeated exposure. 14C burdens in the blood, liver, kidneys, lungs, and fat were measured at 0, 16, and 48 hr after exposure. The labeled material excreted in the urine and expired air was collected for 48 hr. Analysis was performed on both the rats and total amounts eliminated. The mercapturic acid percentage of the urinary metabolites excreted in the first 24 hr was measured. The 14C burdens of all tissues increased in proportion to increased exposure concentrations, except for adipose tissue burdens, which increased more than 30-fold between 100 and 700 ppm. Respiratory elimination of 14C also increased disproportionately. The urinary metabolite profile was altered, with a dose-dependent decreased in the mercapturic acid percentage from 68% at 100 ppm to 51% at 700 ppm. Changes due to multiple versus single exposures were higher tissue burdens 48 hr after exposure, less total excretion of label, a lesser percentage of the total excreted through respiration, and a change in the rate of respiratory excretion. The dose-dependent changes are postulated to be due to saturation of the metabolic elimination of chlorobenzene. The effect of multiple exposure is apparently some stimulation of metabolism.