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Biomedical subjects

J Tinker

Publications and source records attributed to J Tinker.

At least 37 records · Page 2Linked to original sources

Continuous tissue pH and transcutaneous PO2 measurement as an index of tissue perfusion in critically ill patients.

Measurements of transcutaneous PO2 (tcPO2) and tissue pH (pHt) were compared with arterial values in 28 critically ill patients. Eleven of the patients were undergoing continuous flow cardiopulmonary bypass and the other 17 were admitted to the Intensive Therapy Unit (ITU) suffering from a variety of medical and surgical disorders. A total of 135 observations were made on the 28 patients. The overall correlation between the two sets of measurements was poor. The correlation coefficient (r) between arterial PO2 (Pa,O2) and tcPO2 was 0.41 (P less than 0.01) and between arterial pH (pHa) and pHt 0.67 (P less than 0.01). However, the value varied greatly in different groups of patients. In those patients with cardiopulmonary failure, the tcPO2 and pHt measurements rapidly and accurately reflected changes in peripheral tissue perfusion, by contrast the core-peripheral temperature deficit did not change significantly. It is concluded that the technique can be used as a sensitive index of peripheral blood flow and may have prognostic significance

Adult

Relating mutagenicity to chemical structure.

A computer program correlating chemical structure with mutagenesis activity has been developed as a predictive test for hazard evaluation. Sets of substructural units are derived from complete structure, and the probability that a structure containing a given unit will have a designated category of activity is calculated. The program, validated by bacterial mutagenesis testing, is capable of identifying similar structures, showing why they are similar, and estimating the activity of a structure.

Computers

Amino acid acylation: a mechanism of nitrogen excretion in inborn errors of urea synthesis.

Treatment of a patient deficient in carbamyl phosphate synthetase with benzoate or phenylacetic acid resulted in an increase in urinary nitrogen, which could be accounted for by the respective amino acid acylation product, hippurate or phenylacetylgultamine. Benzoate treatment of four hyperammonemic comatose patients led to clinical improvement and a return of plasma ammonium levels toward normal.

Adolescent

Inotropic drugs in acute circulatory failure.

The use of inotropic drugs in patients requiring acute circulatory support is reviewed. A knowledge of their various peripheral effects is essential if the appropriate drug is to be used. The place or pressor amines, digitalis, salbutamol and glucagon in the treatment of patients with poor tissue perfusion is limited. Of the catecholamines, adrenaline causes excessive renal vasoconstriction and peripheral gangrene, noradrenaline increase myocardial work and diminishes peripheral perfusion and isoprenaline distributes blood away from the vital organs, namely: brain, kidneys, heart and mesentery. Dopamine is a useful agent as it enhances renal blood flow in low doses and is not excessively chronotropic. Dobutamine has not yet been shown to have significant advantages over other inotropes and requires further examination.

Adrenergic alpha-Agonists

Continuous tissue pH measurement in critically ill adults with a miniaturised glass electrode.

A continuously reading subcutaneous pH electrode has been developed which gives relatively stable readings when applied to any well perfused part of the body. The results obtained with this electrode have been compared with the actual pH of the arterial blood measured by conventional methods. Thirty patients were studied and one hundred and sixty three observations were made. The correlation coefficient (r) between tissue pH (pHt) and arterial pH (pHa) was 0.76 (P less than 0.01). The response time of the electrode in vitro was less than one minute and, in vivo, stabilization of the recording occurred in less than three minutes. It was found that the discrepancy between pHa and pHt gave a good indication of the adequacy of tissue perfusion.

Adult

Characteristics of transcutaneous oxygen tension monitors in normal adults and critically ill patients.

The performance characteristics of two transcutaneous PO2 monitors were detailed in eleven healthy adults and eighteen critically ill patients (twelve following cardiopulmonary bypass). There was no significant difference in their performance when blood was used as the calibrating medium. In critically ill patients they proved to be of value for recording short term trends in arterial PO2 rather than for measuring absolute values.

Adult

The measurement and control of myocardial infarct size.

Direct, chemical, electrocardiographic and radio-isotopic methods are described for the estimation of myocardial infarct size in animals and man. Their relative points and failings are discussed. The effects of interventions, physical, metabolic and pharmacological, upon the size of myocardial infarcts, are examined and work attempting to reduce myocardial infarct size in man reviewed.

Animals