PubMed Health⌕ Search

Biomedical subjects

N M Raine

Publications and source records attributed to N M Raine.

6 recordsLinked to original sources
PubMed2001

The influence of recovery posture on post-exercise hypotension in normotensive men.

PURPOSE: Postexercise hypotension may be the result of an impaired vasoconstrictor response. This hypothesis was investigated by examining the central and peripheral hemodynamic responses during supine and seated recovery after maximal upright exercise. METHODS: After supine or seated baseline measurements, seven normotensive male volunteers completed a graded upright cycling protocol to volitional exhaustion. This was immediately followed by either supine or seated recovery. Measurements of pulsatile arterial blood pressure and central and peripheral hemodynamic variables recorded 30 min before exercise were compared with those taken throughout 60 min of recovery. RESULTS: Compared with baseline, mean arterial pressure (MAP) was reduced after exercise (P < 0.05) although the degree of change was not different between the supine (-9 +/- 4 mm Hg) and seated positions (-6 +/- 2 mm Hg). This change in MAP was associated with a reduction in diastolic blood pressure (DBP) (P < 0.05) and arterial pulse pressure (APP) (P < 0.01) for the supine and seated positions, respectively. The reduction in APP during seated recovery was accompanied by a decline in stroke volume (SV) (P < 0.05), not seen in the supine position, that limited the contribution of cardiac output (CO) to the maintenance of MAP. This effect of seated recovery was compensated by greater systemic (SVR) and regional vascular resistances in the forearm (FVR) and the forearm skin (SkVRA). There was also evidence of an augmented return of FVR and SkVRA to resting levels in the seated position after exercise. CONCLUSION: The lower peripheral resistance in the supine compared with seated recovery position suggests there is potential for greater vasoconstriction, although this is not evoked to increase blood pressure. This further suggests that the arterial baroreceptor reflex is reset to a lower operating pressure after exercise.

Adult↗
PubMed1999

A simplified paired neck chamber for the demonstration of baroreflex blood pressure regulation.

In this investigation a simplified variable-pressure paired neck chamber was developed as a practical alternative to traditional neck collar designs used to study the arterial baroreceptor reflex in humans. The purpose of this new design was to extend the use of the noninvasive neck chamber method of baroreceptor investigation to teachers of physiology. Performance tests indicate that these new chambers are capable of delineating the stimulus-response relationship for both the blood pressure baroreflex [sensitivity = 0.425 +/- 0.13 mmHg mean arterial pressure (MAP)/mmHg neck chamber pressure (NCP); range = 24.9 +/- 4.6 mmHg MAP] and the heart rate baroreflex (sensitivity 0.273 +/- 0.12 beats.min-1.mmHg NCP-1; range = 16.7 +/- 6.8 beats/min). This was achieved by applying localized positive and negative air pressures to the carotid sinuses throughout the range from +60 to -60 mmHg in steps of 20 mmHg. This simplified neck chamber method offers distinct methodological advantages over traditional neck collars, making it a valuable tool for demonstrating baroreflex regulation of the circulation.

Animals↗
PubMed1995

KTP-532 laser tonsillectomy--a potential day-case procedure?

We report the results of a prospective pilot study of 54 adult patients undergoing tonsillectomy using the KTP-532 laser, designed to assess whether the technique would facilitate day-case adult tonsillectomy. Subjective and objective assessment at six hours post-operatively showed that only 43 per cent could, in our judgement, have been discharged at this interval. Furthermore, the overall complication rate was 31 per cent with a secondary haemorrhage rate of 19 per cent. We conclude that KTP-532 laser tonsillectomy as performed in this pilot study compares unfavourably with dissection tonsillectomy and we discuss possible reasons for this.

Adolescent↗
PubMed1995

Human gastrin and vasoactive intestinal polypeptide responses to endurance running in relation to training status and fluid ingested.

1. Plasma concentrations of gastrin, glucose, vasoactive intestinal polypeptide and non-esterified fatty acid were analysed in six male endurance runners and six male hockey players before, during and 15 min after 90 min treadmill running at 65% maximum oxygen uptake under two conditions: no fluid ingestion (trial A) and ingestion of 8% maltodextrin solution (trial B). 2. Exercise resulted in significantly elevated plasma gastrin concentrations compared with resting values in both groups after trial A (endurance runners, 69.4 ng/l; hockey players 71.4 ng/l) and trial B (endurance runners, 105.5 ng/l; hockey players, 83.2 ng/l). The gastrin response was not significantly different between the trials. 3. Plasma vasoactive intestinal polypeptide levels increased significantly beyond resting levels for both groups during trial A (endurance runners, 76.1 +/- 53.7 ng/l; hockey players 155.6 +/- 41.9 ng/l) and trial B (endurance runners 47.5 +/- 21.3 ng/l; hockey players 132.9 +/- 43.9 ng/l). The vasoactive intestinal polypeptide response to trial B was significantly attenuated compared with trial A. 4. There were no significant differences between endurance runners and hockey players for plasma gastrin, although hockey players produced significantly elevated concentrations of plasma vasoactive intestinal polypeptide after both trials compared with endurance runners. 5. Plasma glucose levels throughout trial B were significantly greater than after trial A irrespective of the group. Plasma glucose concentrations were not significantly different between endurance runners and hockey players. 6. Plasma non-esterified fatty acid concentrations rose significantly for both groups throughout exercise. Trial B resulted in an attenuated non-esterified fatty acid response compared with trial A.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗