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Biomedical subjects

R Strong

Publications and source records attributed to R Strong.

70 records · Page 4Linked to original sources

Impact of a cardiology data bank on physicians' prognostic estimates. Evidence that cardiology fellows change their estimates to become as accurate as the faculty.

To determine whether physicians would be influenced by the prognostic information in a large coronary artery disease data bank, cardiology faculty and fellows made initial estimates of the prognoses of their patients and then made revised final estimates after seeing the outcome of matched patients (OMP) from the data bank. The faculty cardiologists' original estimates proved to be as accurate as those of the data bank's OMP, and the faculty revised their estimates minimally in response to the data bank's OMP. Conversely, the cardiology fellows' original estimates were less accurate than the data bank's OMP, and under all observed circumstances the fellows responded more to the data bank's OMP than did the faculty. As a result, the accuracy of the fellows' final estimates was similar to the accuracies of both the faculty cardiologists and the data bank's OMP. Computerized data banks seem more likely to have impact when their information is provided to physicians who are relatively inexperienced with the disease in question.

Cardiology

Age-related alterations in the rodent brain cholinergic system and behavior.

Pre- and postsynaptic cholinergic markers were studied in various brain regions of mice and rats aged 6 to 30 months in an attempt to determine whether alterations in this transmitter system occur during the normal aging process. Reliable decreases in cholinergic receptor binding and choline acetyltransferase (CAT) activity were found in the cerebral cortex and corpus striatum. These alterations in the cholinergic system were typically more consistent and robust than changes involving glutamic acid decarboxylase, and enzyme marker for GABA neurons. No statistically significant changes in any markers were found in the hippocampus of either species. Significant age-related changes in retention of passive avoidance learning and locomotor activity were also observed in these same animals. These findings demonstrate that changes in the cholinergic system occur naturally in aged mice and rats and that both the loss of cholinergic receptors and decrease in cat activity may contribute to the motor and mental impairments that often accompany old age.

Aging

Phasic vagal influence on inspiratory motor output in anesthetized human subjects.

Vagal influence on inspiratory motor output was assessed in 20 normal subjects and in 12 patients with respiratory disorders under enflurane anethesia using the method of airway occlusion. The change in inspiratory duration during occlusion (delta TI) was measured from mechanical parameters (respiratory flow and tracheal pressure). In eight of the subjects, however, the effect of occlusion and augmentation of tidal volume was further evaluated from diaphragmatic electromyogram. In normal subjects delta TI (mechanical) averaged 0.15 s (range -0.1 to +0.77 s) and correlated with the duration of inspiration during occlusion. Electromyographic observations indicated that the change in neural TI exceeds the change in mechanical TI by approximately 0.2 s and that augmentation of tidal volume shortens TI with no apparent volume threshold. There was a tendency for vagal influence to be higher with restrictive lung disease and lower with obstructive airway disease. These observations indicate that a majority of humans display a significant vagal influence on TI in the spontaneous tidal volume range under anesthesia.

Aged

A simple electrophoretic technique for the estimation of complement C3 conversion: specific application to the investigation of anaphylactoid response to I.V. agents.

A simple electrophoretic technique employing commercially available agarose films is described for the routine estimation of plasma complement C3 conversion. This technique has particular value in the investigation of anaphylactoid responses in patients following the administration of intravenous hypnotic drugs, plasma substitutes or radio-contrast media.

Alfaxalone Alfadolone Mixture

Comparison between a microdiffusion and an ion exchange method for the determination of plasma ammonium.

The results of plasma-ammonium determinations by an ion-exchange method and by a microdiffusion method were compared on the same specimens with each other and with ammonium determinations carried out on the corresponding whole-blood specimens by the microdiffusion method. The plasma-ammonium levels of whole-blood specimens were higher than those of the corresponding plasma specimens, but the difference was not constant. Recoveries of added NH(4) from plasma by the microdiffusion method ranged from 65 to 144%. Recoveries of NH(4) from the same specimens by the ion-exchange method ranged from 93 to 96%. Of the two, the ion-exchange method was the only one of value.

Adolescent

Pre-operative nutritional support in children with end-stage liver disease accepted for liver transplantation: an approach to management.

Pre-operative nutritional support was studied in 28 children with end-stage liver disease awaiting orthotopic liver transplantation. Nasogastric supplemental administration of a standard semi-elemental enteral nutritional formula was compared with a similar formula enriched with branched chain amino acids, and with a group receiving oral nutrition only. The duration of treatment in all groups was similar (mean 90 days). Energy intakes in the supplemented groups were 120-150% of recommended daily intakes (RDI), whereas ad libitum intakes in the oral group ranged 58-100% RDI. A significant improvement in mean Z-score for body weight (denoting catch-up) was noted only in those children who received nasogastric supplements enriched with branched-chain amino acids. The standard enterally-fed group maintained their body weight and Z-scores did not change significantly. In contrast, body weight Z-scores in those fed orally declined significantly. Nutritional supportive therapy of malnourished children with end-stage liver disease can minimize or improve nutritional status in children awaiting liver transplantation. The use of nutritional formulae rich in branched-chain amino acids may have nutritional advantages in children with chronic liver disease which require further study and evaluation.

Amino Acids, Branched-Chain