The presence of an alpha-adrenoceptor--mediated coronary vasoconstrictor reflex during acute systemic hypoxia was examined in thirteen chloralose-anesthetized dogs. Local vasodilator effects were avoided by perfusing the left common coronary artery (LCC) with normoxic blood, while the dogs were ventilated with 5% 02-95% N2 . Left ventricular afterload was held constant and positive cardiac inotropic responses and beta two-adrenoceptor-mediated coronary vasodilation were blocked by propranolol. Parasympatheticmediated bradycardia and coronary vasodilation were blocked with atropine. Systemic hypoxia decreased LCC flow to normoxic myocardium by 19.4+2.6 %. Although myocardial oxygen extraction increased 9.7+2.9 %, myocardial oxygen consumption decreased 16.5+2.6 %. Intracoronary prazosin prevented the reflex vasoconstriction during repeated hypoxia.

An investigation of the ratio of free to bound phenytoin in overdose cases was accomplished by three studies to answer these questions: 1. Will the free to bound ratio change with increasing total phenytoin concentration? 2. Will the free to bound ratio be altered with decreasing total protein concentration? 3. Do these results correlate with overdose cases? The results demonstrated that the ratio of free to bound phenytoin remains constant throughout the therapeutic range as long as a person has a normal total protein concentration. However, the free to bound ratio changes significantly when the total protein decreases by 25 per cent. This substantiates the importance of monitoring free and total phenytoin concentrations in hypoproteinemia.

Ten caucasian male quadriplegics were compared with eight sedentary caucasian male controls in regards to left ventricular dimensions and mass obtained from echocardiograrns. The interventricular septum (IVS), left ventricular posterior wall (LVPW) and left ventricular internal diameter (LVII) were within normal limits for both groups. However, the INS in the SCI were significantly thicker than controls (p <0.05). Myocardial thickness was larger in SCI subjects (p <0.05). Absolute left ventricular mass (LVM) and total left ventricular volume was not different ( p > 0.05), but SCI subjects had significantly greater LVM to lean body mass ratios. Echocardiographically, SCI patients demonstrate concentric hypertrophy. This suggests adaptive response to chronic increase in afterload pressure secondary to their daily activities and muscle spasticity.

A model was developed to predict the increased physiological effort of wearing a respiratory protective device. Specifically, the model was designed to predict the effects of varying ventilatory demands on eleven respiratory variables of the man-respirator system, breath frequency (f_b), tidal volume (V_t), inspiratory flow (dvi/dt), expiratory flow (dve/dt), inspiratory mask pressure (P_mi), expiratory mask pressure (P_me), inspiratory intrathoracic pressure (P_ii), expiratory intrathoracic pressure (P_ie), inspiratory mask work (W_mi), expiratory mask work (W_me), and mask leakage index (L_i). The model was tested by experiment in which three male subjects underwent maximal exercise testing with and without the "pressure-demand" respirator. The eleven variables were determined for each thirty second period utilizing on-line computer analysis. Application of the model to these experimental conditions resulted in significant (p<.001) relationships between each of the predicted and observed variables.

Wretlind, Heden, and Wadstrom found ammonium sulfate to be inhibitory for the formation of extracellular protease in Aeromonas hydrophila grown in Brain Heart Infusion medium. They demonstrated by manipulating the iron and zinc content within their medium that it is possible to differentially affect the accumulation of hemolysin and protease by A. hydrophila grown in batch culture. Further manipulation of the composition of this medium was done in the present study to determine the effect of other components on the production of protease. The purpose of this study was to determine the factors affecting the level of A. hydrophila protease produced in a chemically defined medium.

Histamine is present in the central nervous system and is believed to be derived from neurons (50 percent) and mast cells (50 percent). This experiment was designed to analyze histologically the numbers and distribution of brain-associated mast cells in normal (+/+), mast cell deficient (W/W^v) and heterozygote (W/+, W^v/+) mice of the WBB6F_1 /J strain. Significant variations in the number and distribution of mast cells between the various genotypes were found. Based on the results, a hypothesis is proposed to account for the observed genotypical differences in mast cell numbers and distribution. Based on the total number of mast cells and the content of histamine in a typical mast cell, it is apparent that the mast cell is not a major source of brain histamine, suggesting that another non-neuronal pool of histamine must be present in the brain.

Mice were exposed to diesel exhaust for 9 months prior to evaluation for benzo(a)pyrene disposition. On the last day of exposure the mice were instilled intratracheally with tritiated-benzo(a)pyrene ([3H]BP). The mice were sacrificed at intervals of 2, 24, and 168 hours. Disappearance of radioactivity from lungs and liver was rapid and essentially linear with time. In lungs, liver, and testes; [3H]BP metabolites were found mainly as conjugates, a form readily excretable. Clearance of the hydrocarbon from liver and testes in exposed mice was not markedly different from that in nonexposed mice. However, mice exposed to diesel exhaust had delayed [3H]BP clearance from lungs, possibly due to [3H]BP adsorption to diesel smoke particles.