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R Amyot

Publications and source records attributed to R Amyot.

At least 37 records · Page 2Linked to original sources
PubMed1984

Dopamine effect on bronchomotor tone in vivo.

The effect of increasing doses of dopamine (inhaled or infused) on pulmonary resistance (RL) was measured in 4 normal and in 4 asthmatic subjects. Dopamine, in doses sufficient to raise systolic blood pressure 25 mmHg, did not change RL. However, dopamine, inhaled and infused, significantly decreased histamine-induced bronchoconstriction both in normal and in asthmatic subjects. Thus, we conclude that if dopamine is released by the adrenal medulla during an asthmatic attack, it should have a beneficial rather than a deleterious effect.

Adult↗
PubMed1983

Influence of chronic obstructive lung disease on the disposition of an acidic drug (sulfamethazine).

The influence of chronic respiratory failure (CRF) on the pharmacokinetics of an acidic drug has been studied in 11 patients and in eight normal volunteers who received 10 mg/kg of oral sulfamethazine. Blood and urine samples were collected for 24 and 48 hours, respectively. No differences were observed in the rate of sulfamethazine absorption, but bioavailability was decreased when compared with control subjects. Sulfamethazine volume of distribution (Vd) was larger in patients than in control subjects. These differences in Vd may be secondary to an increase in sulfamethazine unbound fraction. No differences were observed in sulfamethazine elimination. It is concluded that in patients with CRF sulfamethazine bioavailability decreases, and Vd increases secondary to a decrease in binding. Despite the fact that plasma concentrations of the test drug will be decreased, the administration of higher doses may not be advisable.

Absorption↗
PubMed1977

In vivo gas trapping induced by nitrous oxide.

Repeated vital capacity (VC) breaths in 17 anesthetized and curarized dogs induced a small but significant increase in residual volume (RV). This trapping was greatly enhanced when a mixture of 80% N2O and 20% O2 (N2O-O2) was used instead of air. VC breaths with N2O-O2 also increased closing volume, closing capacity and closing pressure determined with 133Xe. Successive quasi-static pressure volume (PV) curves of the lung showed a shift to the right at high lung volume and to the left at low lung volume. Again these changes were more impressive with N2O-O2). The PV curve of the chest wall was unchanged. Insufflations from RV were necessary to produce the gas trapping. Increase in RV was positively related to the size of the inspired volume, to N2O concentration, and inversely related to the inspiratory flow rate. Vagotomy, intravenous isoproterenol, and intravenous propanolol did not alter the phenomena. We propose that these observations can be explained by the presence of foam in the airways and that N2O leads to an increase of foam by osmotic liquid shift into the bronchioli, and/or to an increase in bubble's size by gas diffusion.

Animals↗
PubMed1967

J.A.

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Canada↗