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Biomedical subjects

R A Hall

Publications and source records attributed to R A Hall.

At least 145 records · Page 8Linked to original sources
PubMed1973

Tobacco and evoked potential.

Significant changes were found in two indices of the averaged visual evoked potentials in nine smokers after 12 and 36 hours of abstinence and after resumption of smoking. There was a decrease of the amplitude envelope accompanying withdrawal and an increase with resumption of smoking. These changes are consistent with the contention that tobacco increases arousal. Amplitude changes were found in a specific component of the evoked potential occurring between 100 and 125 milliseconds after the onset of the flash. The latter changes suggest the possibility that smoking selectively enhances the perceptiont of weak stimuli.

Adult↗
PubMed1972

Five- to eight-year results of truncal vagotomy and pyloroplasty for duodenal ulcer.

From January 1963 to December 1965 inclusive 192 men with duodenal ulcer were treated by elective truncal vagotomy and pyloroplasty with one death. Ten subsequent deaths were due to causes unrelated to the ulcer or operation, and 17 patients became untraceable. The remaining 164 patients have been followed up for five to eight years. The late results have been compared with those obtained in a previous study of patients five to eight years after truncal vagotomy and gastroenterostomy, truncal vagotomy and antrectomy, and subtotal gastrectomy respectively for duodenal ulcer.Of the various postgastric operation syndromes early dumping, late dumping, bilious vomiting, and diarrhoea were all less frequent, but not significantly so, after vagotomy and pyloroplasty than after vagotomy and gastroenterostomy.Recurrent ulceration was commoner after vagotomy and pyloroplasty than after all the other operations, the incidence of proved and suspected recurrent ulcers being respectively 6.7 and 7.3% after vagotomy and pyloroplasty, but only 2.5 and 5.9% after vagotomy and gastroenterostomy, 0 and 5.2% after vagotomy and antrectomy, and 0.9 and 3.7% after subtotal gastrectomy. The differences between vagotomy and pyloroplasty and vagotomy and antrectomy or subtotal gastrectomy are statistically significant, but those between vagotomy and pyloroplasty and vagotomy and gastroenterostomy are not.Overall assessment (Visick grading) of the outcome gave poorer results after vagotomy and pyloroplasty than after any other operation, with 14% of category IV cases after vagotomy and pyloroplasty, 11% after vagotomy and gastroenterostomy, 8% after vagotomy and antrectomy, and 6% after subtotal gastrectomy-differences that are significant between vagotomy and pyloroplasty and vagotomy and antrectomy or subtotal gastrectomy but not between vagotomy and pyloroplasty and vagotomy and gastroenterostomy.In the light of these findings it is suggested that truncal vagotomy and pyloroplasty has not lived up to expectations and its place as the currently most popular procedure in the elective surgical treatment of duodenal ulcer should be reconsidered.

Bile↗
PubMed1971

Barbiturate assay.

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Barbiturates↗
PubMed1970

Evoked response and behavior in cats.

Electroencephalographic averaged evoked responses to flashing lights of four different intensities were recorded in ten cats and correlated with behavior. Animals showing a high degree of exploratory behavior, aggressiveness, and activity and little withdrawal showed relatively large increases in amplitude of the averaged evoked response with increases of stimulus intensity. Those showing opposite behavioral traits had small increases or decreases of average evoked response amplitude with increases of stimulus intensity. These findings are compatible with those reported for human subjects. Inference is made about a neurophysiological mechanism for stimulus intensity modulation.

Aggression↗
PubMed1970

Adsorption of serum calcium by plastic sample cups.

Sera left overnight in plastic AutoAnalyzer sample cups may give low calcium values; the effect is attributed to adsorption of calcium onto the walls of the vessel. The adsorption is brought about by a rise in the pH of the sera, and factors which promote the rise in pH increase the adsorption. This phenomenon is of practical importance because as much as 10% of the calcium in the serum may be adsorbed. Adsorption occurs particularly onto the walls of polystyrene cups, and when polypropylene cups were used the adsorption was reduced. The phenomenon cannot be evaluated or controlled by the use of control sera. In order to avoid the sampling error, serum for calcium analysis should be used fresh or stored at 4 degrees C under conditions such that any change in pH is minimal. Sera should not be left to stand in AutoAnalyzer cups at room temperature for longer than three hours before analysis.

Adsorption↗