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Biomedical subjects

D J Stone

Publications and source records attributed to D J Stone.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Determination of the adsorption of tramadol hydrochloride by activated charcoal in vitro and in vivo.

Although tramadol is one of the most widely used centrally acting analgesics worldwide, no literature is available regarding adsorption of tramadol HCl powder or tablets (Ultram; 50 mg tramadol HCl per tablet) by activated charcoal (AC) for use as potential adjunct treatment of overdose. The present study incorporated a novel combination of in vitro and in vivo methods to investigate this question. Based on a binding curve of tramadol UV absorbance (UV(a); 225 nm) plotted against the amount of AC, the ratio of amount of tramadol completely adsorbed by AC was 0.05 mg/mg. Also based on UV(a), no tramadol was detected in filtrate of slurries in which up to 62 tablets of Ultram were mixed with 50 g AC; 4.6% of unbound tramadol was detected when 100 tablets of Ultram were mixed with AC. The ratio of amount of tramadol completely adsorbed by AC in this test was 0.10. In vivo, co-administration of 0.1 g/ml of AC produced a 13- to 14-fold rightward shift in tramadol's antinociceptive dose-response curve and a 1.6-fold rightward shift in tramadol's lethality dose-response curve.

Adsorption↗
PubMedDate not supplied

The effects of proprandolol and histamine on the ventilation response to carbon dioxide inhalation in normal subjects.

A method was developed to measure the oxygen cost of ventilation during CO2 rebreathing. In 20 healthy normal subjects SGaw, MMEF, and FEV1 were measured prior to and following the infusion of propranolol. In five of the same subjects airway constriction was induced by inhalation of histamine. The use of both agents was followed by a significant decrease in the ventilation response to carbon dioxide inhalation. Even more significantly, the oxygen cost of the increase in ventilation measured during CO2 rebreathing rose significantly following either propranolol or histamine.

Adult↗
PubMedDate not supplied

Comparison of the ventilation response to CO2 rebreathing in healthy smokers and nonsmokers and subjects with bronchitis.

A comparison of ventilatory tests and the response to carbon dioxide rebreathing was made in healthy smokers, nonsmokers, and in subjects with bronchitis. The response to carbon dioxide (CO2) rebreathing was the same in the healthy population but diminished in the bronchitic group. Effects of smoking on maximal expiratory flow rates did not correlate with the results of carbon dioxide rebreathing. A consistent pattern of relationship of ventilation response to carbon dioxide and age of the subject was apparent.

Adult↗
PubMedDate not supplied

Vascular effects of 2-chloroprocaine and sodium metabisulfite on isolated rat aortic rings.

Neurologic deficits have followed the intrathecal injection of 2-chloroprocaine 3% (10(-1) M) with sodium metabisulfite 0.2% (10(-2) M) as a preservative. This study evaluated the effects of varying concentrations of 2-chloroprocaine and sodium metabisulfite, as well as the combination of the two, on the vascular reactivity of isolated rings of rat thoracic aorta. Isolated Sprague-Dawley rat thoracic aortic rings were prepared and connected to force transducers for measurement of isometric tension. The tension produced by log-arithmically increasing concentrations of 2-chloroprocaine, sodium metabisulfite, and their paired combination was measured. Sodium metabisulfite concentrations below 0.2% (10(-2) M) caused a maximum of 40% vasoconstriction compared to control followed by vasodilation with a maximum of 80% at 10(-2) M (the concentration in the former clinical preparation). 2-chloroprocaine alone produced a progressive relaxation at 10(-3) M or higher concentration with a maximum of 130%. The effects of the mixture of sodium metabisulfite and 2-chloroprocaine were identical to the effects produced by 2-chloroprocaine alone. The relaxation effects of 2-chloroprocaine dominate the vasoconstricting effects of sodium metabisulfite when the two drugs are combined.

Anesthetics, Local↗