Biomedical subjects
Publications and source records attributed to R M Jones.
The anaesthetized, heparinized health adult dogs were infused with protamine sulphate 3 mg X kg-1 and plasma ionized calcium was measured. A significant (p less than 0.01) decrease in ionized calcium occurred which preceded the maximal reduction in cardiac output and systemic arterial pressure. The clinical implications of these results are discussed.
The external nares rarely close completely during positive pressure lung filling in Bufo marinus. Simultaneous measurement of airflow at the nares and transnarial pressure revealed continuous airflow (out) during lung emptying (nares open) and the subsequent lung filling (nares partially closed). Expiratory minute volume (VE) measured at the nares is consistently greater than VE from the lungs because the buccal contents are being simultaneously forced into the lungs and out the partially closed nares. The relation between narial resistance and ventilatory parameters during hypercapnia was investigated to determine if control of the narial aperture is an important variable related to the volume of air transferred to and from the lungs and buccal chamber. Buccal frequency decreased (from 73 to 30/min) and buccal TE (time for expiratory air flow at the nares) increased (from 0.28 to 0.41 sec) when breathing 2% CO2. Mean narial resistance was 0.40 cm H2O/L . min, maximum narial resistance was 0.44 cm H2O/L . min, and both were uninfluenced by CO2. Lung ventilation frequency increased with 2% CO2 (from 5.3 to 20.8/min). TE of lung ventilation cycles remained constant (about 0.45 sec) while VTE (expiratory tidal volume at the nares) increased from 0.73 to 0.90 ml/100 g. Mean narial resistance during lung ventilations decreased from 3.80 to 1.76 cm H2O/L . min with 2% CO2. Maximum narial resistance during lung ventilations was unchanged. It is concluded that the nares may remain open for a longer proportion of each lung ventilation cycle during hypercapnic hyperpnea.
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When six normal men took probenecid with ketoprofen in a two-treatment crossover study, steady-state plasma concentrations of ketoprofen and ketoprofen conjugates rose, but plasma protein binding of ketoprofen and urinary excretion of ketoprofen conjugates decreased. Probenecid decreased protein binding of ketoprofen by 28 +/- 7%, total ketoprofen clearance by 67 +/- 11%, clearance of unbound ketoprofen by 74 +/- 10%, clearance of unbound ketoprofen by conjugation by 91 +/- 5%, and renal clearance of ketoprofen conjugates by 93 +/- 4%. An apparent decrease (22 +/- 29%) in unbound ketoprofen clearance by mechanisms other than conjugation might have been established in a study of more than six subjects. Probenecid, which reaches plasma concentrations that approach 100 times those of ketoprofen or its conjugates, appears to inhibit both the conjugation of ketoprofen and the renal excretion of ketoprofen conjugates. An alternative explanation to inhibition of conjugation involves cumulation and subsequent hydrolysis of ketoprofen conjugates as a result of the renal action of probenecid. In addition to the advantages of obtaining simultaneous uricosuric and anti-inflammatory effects, there may be clinical kinetic advantages of administration of probenecid with ketoprofen, because the large interdose concentration swings of ketoprofen are then substantially reduced.
A case of multiple endocrine adenopathy type I associated with a solitary carcinoid tumour is described. During anaesthesia and characteristic syndrome consisting of hypertension, tachycardia and flushing occurred. The possible mechanism for this are discussed.
Terbutaline sulphate (0.25 mg) was given intravenously to 10 recumbent patients with severe irreversible airflow obstruction and pulmonary hypertension who were undergoing right heart catheterisation. Alveolar ventilation index, cardiac index, and mean pulmonary artery pressure all rose significantly at 5 minutes and then fell by 35 minutes, although the first two remained higher than control levels. This was accompanied by a small but significant rise in arterial oxygen tension at 5 minutes. There were no significant changes in ventilation-perfusion relationships at either 5 or 35 minutes.
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In a set of isogenic strains, three out of four different dnaB(ts) mutations reduced surface exclusion between F' plasmids. In further studies with a strain carrying one of these mutations (dnaB43), surface exclusion remained reduced in the presence of a recombinant plasmid carrying only the region of F that encodes the surface exclusion proteins TraSp and TraTp. The dnaB analog specified by bacteriophage P1 but not that specified by P7 increased the surface excluding ability of the strain carrying dnaB43 to the same level as the isogenic dnaB+ strain. The possible role of the dnaB gene in surface exclusion is discussed.
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To assess an interaction between ketoprofen and aspirin we gave both drugs orally, to steady state, to healthy men. Although ketoprofen did not alter salicylate absorption and disposition, we observed that concurrent administration of aspirin decreased ketoprofen protein binding and increased its plasma clearance. Salicylate also appeared to reduce metabolic ketoprofen conversion to conjugates and their renal elimination. The data suggested that salicylate also enhanced the metabolic conversion of ketoprofen to nonconjugate metabolites (p = 0.091). Our findings indicate that the drug-drug interaction between aspirin and ketoprofen is complex.
Five patients with systemic arterial hypertension occurring in the postoperative period and resistant to sodium nitroprusside are described. The hypertension was associated with evidence of increased activity of the autonomic and renin-angiotensin systems. Sympathetic blockade using the ganglion blocking agent, pentolinium, enabled the arterial pressure to be controlled adequately in all patients. This was associated with a decrease in catecholamine concentrations, plasma renin activity and angiotensin II concentrations.
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The organisation of research in the Department of Anesthesiology at the University of Michigan is described and the comments of a British Senior Registrar working within the system are recorded.
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A 61-year old woman with severe coronary artery disease underwent three-vessel coronary bypass surgery. Difficulty was encountered in terminating cardiopulmonary bypass, but there was dramatic improvement following the administration of intravenous insulin. The use of insulin to facilitate termination of cardiopulmonary bypass is discussed.