Biomedical subjects
Publications and source records attributed to P Macfarlane.
Lower nasal swab and higher nasopharyngeal aspirate samples were compared for RSV immunofluorescence and pain score in infants hospitalised with acute bronchiolitis. The nasal swab procedure was significantly less painful but was negative in approximately one third of RSV positive cases.
BACKGROUND AND STUDY AIM: Colonoscopy is a common gastroenterological procedure for investigation of the bowel. The main side effects of colonoscopy are pain during investigation, cardiovascular complications and very rarely even death. The aim of this study was to compare the continuous fluctuation of heart rate variability (HRV) components during colonoscopy under normal conditions, analgesia/sedation, and total intravenous anesthesia. PATIENTS AND METHODS: 37 consecutive patients (aged 35 - 65), were randomly allocated to three groups: no sedation (control group 1); analgesia/sedation (group 2); and total intravenous anesthesia (group 3). Holter electrocardiography and subsequent frequency domain analysis were undertaken. The low-frequency (LF, 0.04 - 0.15 Hz) and the high-frequency (HF, 0.15 - 0.40 Hz) components were estimated using spectral analysis in the usual way. Normalized units (nu) were calculated from the following equations: LFnu = LF/(LF + HF), and HFnu = HF/(LF + HF). RESULTS: Groups 2 and 3 were found to have a significantly lower HFnu and higher LFnu than group 1 essentially throughout the procedure. A one-way analysis of variance and t-test confirmed that the differences were significant when the colonoscope reached the splenic flexure as were the LF/HF balances at the splenic and hepatic flexures and the cecum. The percentage change in LF/HF was also analyzed, and it was found that in group 3 the mean change was over 136 % when the colonoscope reached the sigmoid flexure, which was significantly higher than in the other two groups. CONCLUSION: Most changes in HRV components occurred during colonoscopy of the left side of the bowel. Analgesia/sedation and total intravenous anesthesia increased HRV by increasing the LF component.
OBJECTIVE: The pathophysiology of the decline in circulating growth hormone (GH) concentrations that may occur with ageing remains elusive. We have investigated the potential contributions of decreased endogenous GH-releasing hormone (GHRH) and increased somatostatin secretion to this phenomenon. DESIGN AND METHODS: The strategy used was to stimulate GH secretion in 8 young (20-24 years old, body mass index (BMI) 22.8 +/- 2.8 kg/m2) and 8 elderly (68-82 years old, BMI 23.4 +/- 1.6 kg/m2) male subjects on separate occasions by means of: (i) intravenous bolus 0.5 microgram/kg D-Ala2 GHRH(1-29)-NH2 alone; (ii) 0.5 microgram/kg GHRH after pre-treatment with two oral doses of 50 mg atenolol (to inhibit somatostatin secretion); (iii) 1.25 mg oral bromocriptine alone (to increase endogenous GHRH and/or inhibit somatostatin); (iv) 50 mg oral atenolol plus 1.25 mg oral bromocriptine; and (v) 0.5 microgram/kg GHRH after pre-treatment with 1.25 mg oral bromocriptine. RESULTS: The elderly men had a significantly lower peak and area under curve (AUC) GH response to intravenous GHRH when compared with 8 young men (peak 3.1 +/- 1.0 ng/ml v. 21.6 +/- 5.0 ng/ml, AUC 205 +/- 56 ng/ml/min v. 1,315 +/- 295 ng/ml/min, P < 0.05). Pre-treatment with atenolol before GHRH administration produced no significant increase in peak and AUC GH response in both groups, which remained lower in the elderly men than in their young counterparts (peak 5.5 +/- 1.8 ng/ml v. 29.3 +/- 7.0 ng/ml, AUC 327 +/- 90 ng/ml/min v. 2,017 +/- 590 ng/ml/min, P < 0.05). Bromocriptine alone did not cause a significant rise in GH concentration in either elderly or young subjects (peak 3.1 +/- 1.1 v. 8.8 +/- 3.2 ng/ml, P > 0.05). When atenolol was administered before bromocriptine, both groups responded but the elderly subjects had a significantly greater peak and AUC response (peak 3.6 +/- 0.7 v. 10.7 +/- 2.1 ng/ml; AUC 191 +/- 39 v. 533 +/- 125 ng/ml/min, P < 0.05). Bromocriptine given before GHRH failed to potentiate GHRH action on GH release in either group. Of 5 elderly men who underwent further evaluation of GH secretory ability, 2 subjects had GH levels > 10 ng/ml, either basally or after intravenous GHRH. The remaining 3 had an initially impaired GH response to bolus intravenous GHRH. After 100 micrograms GHRH subcutaneously twice daily for up to 2 weeks the GH responses to intravenous bolus GHRH (0.5 microgram/kg) were reassessed. One exhibited a normal response (> 10 ng/ml) after 1 week of daily GHRH treatment, another had a near-normal response after 2 weeks (9.7 ng/ml), while the third still had an impaired response by the end of the 2-week treatment period (3.2 ng/ml). CONCLUSIONS: The restoration of endogenous GH secretion in these elderly subjects by means of GHRH priming, and the failure of manipulation of somatostatinergic tone to restore a normal GH response to GHRH suggests that somatotroph atrophy due to a reduction in endogenous GHRH secretion is the principal cause of the diminished GH secretion with ageing.
OBJECTIVES: To determine the impact of socioeconomic status (SES) on coronary heart disease (CHD) mortality in people with and without prevalent CHD at baseline. DESIGN: Cohort study with 25 year follow up; prevalent CHD was defined by Q, ST or T wave electrocardiographic (ECG) abnormalities or symptoms (defined by the Rose chest pain questionnaire and self reported doctor diagnosis) or both. SES was defined by four civil service employment grades. SETTING: London. PARTICIPANTS: 17 907 male civil servants aged 40-69 years. MAIN OUTCOME MEASURES: CHD mortality (n=2695 deaths). RESULTS: The lowest versus highest employment grade was associated with increased CHD mortality (age adjusted hazard ratio 1.56 (95% CI 1.2, 2.1)), prevalence of symptoms and, among symptomatic participants only, the prevalence of Q, ST or T abnormalities. Thirty one per cent of CHD deaths occurred in participants with prevalent CHD at baseline. Among participants without Q, ST or T abnormality employment grade was associated with CHD mortality; the hazard ratios (lowest v highest grade) adjusted for age, systolic and diastolic blood pressure were 1.72 (95% CI 1.4, 2.1) for asymptomatic and 1.52 (95% CI 1.1, 2.1) for symptomatic participants; among participants with Q, ST or T abnormality the corresponding hazard ratios were 1.46 (95% CI 0.7, 2.9) and 1.14 (95% CI 0.6, 2.0) respectively. CONCLUSIONS: SES was inversely associated with CHD mortality in civil servants with and without prevalent CHD at baseline. Further distinguishing the relative contribution of SES to the initiation and progression of CHD requires repeated measures studies of pre-clinical and clinical measures of CHD.
The West of Scotland Coronary Prevention Study (WOSCOPS) showed that pravastatin reduced the risk of coronary heart disease (CHD) events in 6,595 middle-aged hypercholesterolaemic men aged 45-64 years without prior myocardial infarction followed for an average of 4.9 years. We hypothesised prospectively (a) that baseline levels of haemorheological variables were related to baseline and incident CHD and to mortality; and (b) that reduction in lipoproteins by pravastatin would lower plasma and blood viscosity, a potential contributory mechanism to CHD events. We therefore studied plasma and blood viscosity, fibrinogen, haematocrit, and blood cell counts at baseline and 1 year. At baseline, plasma and blood viscosity were related to risk factors, CHD measures, and claudication. On univariate analysis, baseline levels of all rheological variables (except platelet count) were related to incident CHD; CHD mortality; and total mortality. On multivariate analysis including baseline CHD and risk factors, plasma and blood viscosity, haematocrit and white cell count each remained significantly associated with incident CHD; while fibrinogen remained an independent predictor of mortality (all p < 0.03). After one year, lipoprotein reduction by pravastatin was associated with significant reductions (about one quarter of a standard deviation) in plasma viscosity (mean difference 0.02 mPa.s, p <0.001) and in blood viscosity (mean difference 0.06 mPa.s, p<0.001), but was not associated with significant changes in other rheological variables. We therefore suggest that pravastatin therapy, which reduces elevated lipoproteins in hypercholesterolaemic men, may lower risks of CHD and mortality partly by lowering plasma and blood viscosity. Further studies are required to test this hypothesis.
Cross-sectional data from the Whitehall II study baseline were used to identify factors that may lead to the high levels of Rose angina reporting in women. 134 (4.0%) of 3350 women and 164 (2.4%) of 6830 men reported angina (P<0.001). Women with Rose angina had a poorer cardiovascular risk profile (degree of obesity, serum cholesterol and apolipoprotein B, blood pressure) and more electrocardiogram abnormalities (ST and T changes) than women without angina, but the associations were generally weaker than in men. Women who reported many other physical symptoms had a high prevalence of Rose angina (9.7%). Adjustment for symptom reporting reduced the age-adjusted gender difference to odds ratio (OR) = 0.93 (95% confidence interval [CI]: 0.56-1.56) for subjects with no symptoms, and to OR = 1.42 (95% CI = 1.05-1.90) for subjects at the upper quartile of symptom score. Among women a high level of general symptom reporting was associated with General Health Questionnaire (GHQ) minor psychiatric morbidity (51.9% prevalence), but GHQ caseness does not appear to be a predictor of Rose angina (OR 1.22 [0.67-2.21]) in this group. Coronary artery disease risk is raised in women with Rose angina, and this remains true in groups with high levels of general symptom reporting.
OBJECTIVE: The purpose of our study was to evaluate the clinical efficacy of a new self-expanding metallic endoprosthesis in the management of distal colonic obstruction in seven patients. CONCLUSION. The Wallstent enteral endoprosthesis is safe and effective in relieving obstruction in patients with resectable colonic tumors. Once in place, the Wallstent permits planned elective surgery and avoids a temporary stoma. In addition, the Wallstent can palliate patients with obstruction due to advanced colonic neoplasms. The results of our preliminary study are promising and show a low incidence of complications.
Critical events including hypoxaemia, arrhythmias and myocardial ischaemia may occur more frequently during endoscopic procedures than during anaesthesia. A study was undertaken to assess the cardiovascular changes and to evaluate suitable monitoring techniques to detect critical events during sedation and endoscopy. Twenty patients scheduled to undergo a prolonged endoscopic procedure which required deep sedation were studied. Continuous recordings of electrocardiogram, heart rate and arterial oxygen saturation were made and arterial pressure was recorded at one-minute intervals. The study commenced immediately before administration of sedatives, continued for the duration of the examination and for one hour following the examination. Oxygen saturation decreased in all patients during the examination to a mean of 82.9% (SD 11.9), and remained below baseline for the duration of the examination and into the recovery period. Statistically significant increases and reductions of systolic arterial pressure and rate-pressure product were found during the procedures compared with baseline values recorded before administration of sedatives. Sixteen of the 20 patients developed tachycardia during the examination. Ten patients developed ectopic foci which were supraventricular, ventricular or both in origin. Electrocardiogram changes resolved during the recovery period. Myocardial ischaemia was assessed by S-T segment depression and a significant correlation was found between S-T segment depression and hypoxaemia, although the magnitude of the S-T depression was small and may not have been detected clinically. No correlation was found between S-T segment depression and arterial pressure, heart rate or rate-pressure product.(ABSTRACT TRUNCATED AT 250 WORDS)
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