The acute pulmonary function response to graded levels of a low toxicity dust was studied in guinea pigs. Four groups of five male guinea pigs each were exposed to mean concentrations of 0, 0.25, 1.01 and 5.39 mg Foundry Hill Clay l-1 air with mass median aerodynamic diameters of 2.6, 4.6 and 6.7 microns, respectively. There was a 15-min pre-exposure period to clean air, a 1-h exposure to the test atmosphere and then a 1-h recovery period with exposure to clean air. Concentration-related changes, compared to the pre-exposure period, occurred with a rapid onset in a number of parameters. Generally, the severity of observed effects increased with exposure time and, therefore, with inhaled dose. Statistically significant changes (P < 0.05) were observed in tidal volume, dynamic compliance, dynamic resistance, flow, pressure and minute volume during the last 15 min of exposure. The observed changes were consistent with acute bronchoconstriction. These effects reversed rapidly and there were no significant changes 1 h post-exposure. These results suggest that adverse physiological responses of short duration can occur when animals are exposed via inhalation to low-toxicity materials in the concentration range 0.25-5 mg l-1.

Administration, Inhalation↗

PubMedDate not supplied

Use of a head dome system to compare i.v. methacholine-induced bronchoconstriction in conscious vs anesthetized rhesus monkeys.

The use of a newly developed head dome system has allowed measurement of pulmonary function in conscious monkeys. Such information is often desired, so that pharmacological or toxicological effects of administered compounds can be measured in the absence of effects from anesthetic agents. The current study was conducted to gain experience with this method and to allow the determination of the effects of sodium pentobarbital anesthesia (30 mg kg-1 i.v.) on the bronchoconstriction seen during i.v. infusion of methacholine in rhesus monkeys. Bronchoconstriction was measured as changes in respiratory resistance using a Buxco LS20 pulmonary mechanics computer. Four male rhesus monkeys (4.2-5.1 kg) were used. For the anesthetized exposures, the animals were intubated with a 4.0-mm cuffed endotracheal tube attached to a size 'O' Fleisch pneumotachograph. For the conscious exposures, the animals sat in restraining chairs with a custom-built head dome attached to the same pneumotachograph. In both cases, transthoracic pressure was monitored with an intrapleural catheter. Each monkey was infused with methacholine in stepwise doses, while anesthetized and conscious, until a 75% increase in respiratory resistance was seen. The ED50 values of 0.134 and 0.180 mg ml-1 methacholine were not significantly different in anesthetized vs conscious monkeys, respectively.

Airway Resistance↗

PubMedDate not supplied

Comparison of solid-phase extraction and supercritical fluid extraction for the analysis of morphine in whole blood.

A comparative study of the quantitative determination of morphine in whole blood using solid-phase extraction (SPE) and supercritical fluid extraction (SFE) is described. Comparative studies were made of the two techniques for the extraction of morphine from authentic forensic blood specimens. Quantitative results indicate that morphine levels measured using SPE correspond well to morphine levels produced using SFE. The two techniques are therefore comparable, although SFE is faster and cleaner and extracts may be produced with higher analyte recoveries than with SPE. This paper presents a comparison of the two techniques and the morphine concentrations determined in blood.

Analgesics, Opioid↗

PubMedDate not supplied

Accurate occlusal bite guards.

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Bruxism↗

PubMedDate not supplied

The University of Florida general practice residency program.

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Curriculum↗