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Biomedical subjects

T Aitchison

Publications and source records attributed to T Aitchison.

At least 37 records · Page 2Linked to original sources
PubMed1995

Prognostic models for subgroups of melanoma patients from the Scottish Melanoma Group database 1979-86, and their subsequent validation.

For the past 20 years thickness of the primary tumour has been accepted as the most important guide to prognosis for patients with primary cutaneous malignant melanoma. The changing epidemiology of melanoma with an increasing number of patients with thin tumours has necessitated a reappraisal of this, with particular reference to interactions among tumour thickness, the patients' sex and the presence or absence of ulceration of the primary tumour. All primary cutaneous malignant melanomas diagnosed in Scotland between 1979 and 1986 were used as the test group (1978 patients). The proportional hazards model was used on all potential risk factors in the database and their two-way interactions, and the resulting models based on stepwise procedures were subsequently validated on 289 melanoma patients first diagnosed in 1987 in the same geographic area. Four distinct subgroups of males and females with ulcerated or non-ulcerated lesions were identified. For females with ulcerated lesions, tumour thickness, mitotic count and anatomical site of primary all gave valuable prognostic information, whereas for females with non-ulcerated lesions only tumour thickness was of prognostic value. For males with ulcerated lesions, level of invasion was the only prognostic guide, while for males with non-ulcerated lesions both tumour thickness and level of invasion contributed significantly to prediction of prognosis. Prognosis markedly different across subgroups of the melanoma population, even to the extent that essential prognostic factors are not the same in the distinct subgroups. Verification of these prognostic guides derived from 1979-86 patients has been achieved for all patients diagnosed with melanoma in 1987 from the same geographic area. These data will therefore be useful aids for clinicians managing patients.

Adult↗
PubMed1995

A comparison of methods of predicting maximum oxygen uptake.

The aim of this study was to compare the results from a Cooper walk run test, a multistage shuttle run test, and a submaximal cycle test with the direct measurement of maximum oxygen uptake on a treadmill. Three predictive tests of maximum oxygen uptake--linear extrapolation of heart rate of VO2 collected from a submaximal cycle ergometer test (predicted L/E), the Cooper 12 min walk, run test, and a multi-stage progressive shuttle run test (MST)--were performed by 22 young healthy males (mean(s.d.) age 22.1 (2.4) years; body mass 72.4(8.9kg)) and the values compared to those obtained by direct measurement on a maximal treadmill test. All of the subjects were regular exercisers. The mean(s.d.) from the various tests in ml.kg-1.min-1 were as follows: treadmill 60.1(8.0), Cooper 60.6(10.3), MST 55.6(8.0), and predictedL/E 52.0(8.4). The Cooper test had a correlation with the treadmill test of 0.92, while the MST and the predictedL/E had correlations of 0.86 and 0.76 respectively. Both the MST and predictedL/E showed systematic underprediction of the treadmill value. On average, the MST was 4.5 ml.kg-1.min-1 (s.e. 0.9) lower than the treadmill VO2max while the predictedL/E was 7.8 ml.kg-1. min-1 (s.e. 1.4) lower than the treadmill VO2max. These findings indicate that, for the population assessed, the Cooper walk run test is the best predictor of VO2max among the three tests.

Adult↗
PubMed1994

The in vitro proteolytic and saccharolytic activity of Candida species cultured in human saliva.

The proteolytic and saccharolytic activity of 4 Candida species was investigated in batch cultures of pooled, human mixed saliva supplemented with glucose. All the Candida species investigated (Candida albicans, Candida tropicalis, Candida glabrata and Candida krusei) demonstrated a marked growth in saliva with a concomitant reduction in pH from about 7.5 to 3.3, within 72 h. Isotachophoretic analysis of the culture supernatant revealed the presence of a variety of acid anions of which pyruvate and acetate were the most abundant. Proteolysis of salivary components, evaluated by a biochemical assay and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was exhibited by all 4 Candida species, although there was inter-species variation. Despite the similarity in growth rates, C. tropicalis and C. krusei demonstrated greater proteolytic activity than C. albicans and C. glabrata. Neither candidal growth nor proteolysis was observed in glucose-free control saliva samples. In contrast, the degree of saccharolytic and proteolytic activity of a single isolate of C. albicans in glucose-supplemented parotid saliva appeared to be relatively weak compared with mixed saliva. As the oral cavity provides ideal low pH niches periodically supplemented with dietary carbohydrates, the acidic proteinases of Candida species may play a role in the pathogenesis of oral candidiasis.

Analysis of Variance↗
PubMed1993

A comparison of narrow band phototherapy (TL-01) and photochemotherapy (PUVA) in the management of polymorphic light eruption.

Twenty-five patients suffering from severe polymorphic light eruption (PLE) were randomized to either photochemotherapy (PUVA) or narrow-band phototherapy (TL-01 UVB) treatment in early spring; patients receiving UVB were given placebo tablets to achieve a matching therapy procedure. During the 4 months following treatment, patient exposure to solar UVB was monitored with polysulphone badges. PLE occurrence, severity, and restriction of outdoor activity were recorded, using weekly diary-sheets. Analysis of covariance on this data, using the logarithm of UVB exposure as the explanatory variable, showed no significant differences between the treatments. TL-01 UVB is an effective alternative to PUVA in the management of PLE.

Adult↗
PubMed1993

Physiological and psychological responses to a university fitness session.

The purpose of this study was to examine the physiological and psychological responses to a university fitness session entitled 'popmobility'. A popmobility session consists of 20 min of aerobic activities, 5 min of local muscular endurance exercises and 5 min of flexibility exercises. Ten regular participants of these sessions, women of mean(s.d.) age 21.2(1.5) years, took part in the study. A maximal oxygen uptake (VO2max) treadmill test was performed by each subject to obtain VO2max and maximum heart rate values. In a laboratory, heart rate and VO2 were measured throughout a popmobility session for each subject. Rate of perceived exertion (RPE) was measured every 5 min throughout the session. The mean intensity of the aerobic part of the session ranged from 67.7-82.6% of the subject's VO2max (mean of 76.4% VO2max). The mean heart rate reserve for the aerobic section was 75.6%. While the relative oxygen consumption remained fairly static during the aerobic section, the RPE score rose. The mean(s.d.) total energy expenditure was 236.6(28.4) kcal (range 203-288). The popmobility session is of adequate intensity to improve the aerobic fitness of its participants. Heart rate, as used as a measure of intensity during a popmobility session, would appear to be a fairly accurate indicator of intensity. However, the use of RPE for exercise prescription in popmobility sessions is inappropriate. Popmobility could also be useful in a weight-reduction programme.

Adult↗
PubMed1992

Prospective evaluation of the Paediatric Risk of Mortality (PRISM) score.

The performance of the admission day Paediatric Risk of Mortality (PRISM) score for outcome prediction was assessed prospectively in 270 consecutive admissions, aged 3 days to 18.6 years, to a paediatric intensive care unit. Using a cut off of r = 0.00 (expected mortality = 50%), the overall sensitivity (correct prediction of death) was 48% while specificity (correct prediction of survival) was 99%, comparable with the original validation data of the score in the USA. Outcome prediction was most accurate when the stay in the paediatric intensive care unit was between one and four days. Sensitivity was appreciably lower for operative patients (17%) compared with non-operative patients (71%) because of a failure to predict deaths after cardiac surgery. The sensitivity (41%) and specificity (99%) using five variables (systolic blood pressure, Glasgow coma scale, carbon dioxide tension, and serum bicarbonate and serum calcium concentrations) was similar to that using all 14 variables. Six variable ranges related differently with non-survival compared with the score. It is concluded that the performance of the PRISM score is institution independent and good for short stay patients. It underpredicts deaths after cardiac surgery. Only five variables may be needed for satisfactory outcome prediction. Some of the variables need reweighting for paediatric intensive care units in the UK.

Adolescent↗
PubMed1992

The effects of a university fitness programme on health-related variables in previously sedentary males.

This study reports on the effects of a 10-week university fitness programme on health-related fitness variables. Twenty-one male exercisers, aged 37.0(10.3) years (mean(s.d.); range 21-58), and 22 male controls, aged 38.6(7.9) years (mean(s.d.); range 17-54), volunteered to take part. Two sample t-tests and 95% confidence intervals were used to determine if the exercise group demonstrated a greater average improvement than the control group and the average improvement in both groups separately. The exercise group showed a greater average improvement over the controls from Test 1 (before fitness programme) to Test 2 (after) in the following: steady-state heart rate (beats min-1) 95% confidence intervals (-7.8, -16.2); predicted VO2max (ml kg-1 min-1): 95% confidence intervals (3.2, 6.6); sit-ups (repetitions): 95% confidence intervals (3.1, 7.0); flexibility (cm): 95% confidence intervals (3.3, 6.9). There was no significant difference between the exercise group and control group in body weight, percentage body fat, blood pressure, total plasma cholesterol, high-density lipoprotein and triglycerides. The exercise programme improved aerobic fitness, local muscular endurance and flexibility. However, the increase in aerobic fitness did not coincide with beneficial changes in the coronary risk profile.

Adolescent↗
PubMed1991

Stage II melanoma in the west of Scotland, 1976-1985: prognostic factors for survival.

The outcome of 142 patients undergoing therapeutic lymphadenectomy for clinical stage II malignant melanoma was retrospectively assessed. 5 year survival was 26%, and survival was not altered in the 25 patients who received two courses of adjuvant combination chemotherapy after lymphadenectomy. On univariate analysis, the most significant determinants of survival were the number of malignant nodes removed at lymphadenectomy (P = 0.00004), the age of the patient (P = 0.009) and the disease-free interval between primary and stage II disease (P = 0.01). The following features were not significantly related to survival: sex, site, histogenetic type of primary tumour, tumour thickness and level of invasion. The number of malignant lymph-nodes was confirmed on multivariate analysis as the single most useful and significant predictor of survival, with the patient's age providing an additional significant contribution. In future adjuvant trials in stage II melanoma after therapeutic lymphadenectomy, patients should be stratified for both age and number of malignant nodes.

Adolescent↗
PubMed1991

Malignant melanoma occurring in those aged under 30 in the west of Scotland 1979-1986: a study of incidence, clinical features, pathological features and survival.

The study population consisted of the 95 patients who presented with cutaneous malignant melanoma in the west of Scotland between 1979 and 1986 and who were aged under 30 at the time of diagnosis. Over this 7-year period, 1299 melanomas were diagnosed in all age groups in this geographical area, increasing in incidence by 82% from 135 in 1979 to 246 in 1986. The proportion of melanomas diagnosed before the patients' thirtieth birthday remained constant at 6%. None were diagnosed in the under-15 age-group, and none developed on giant congenital naevi. Forty-two of the 95 melanomas (44%) in the under-30 group developed on a small naevus present either from birth or early childhood. These melanomas were thicker than those apparently developing on normal skin, but once controlled for tumour thickness and sex the presence of a pre-existing naevus did not affect 5-year survival. The overall 5-year survival was 76% with poorer survival associated with thicker tumours and male sex. This study suggests that small early onset naevi may have a higher potential for post-pubertal malignant change than has been previously recognized.

Adolescent↗
PubMed1990

Reproducibility of measurements of cardiac output in newborn infants by Doppler ultrasound.

Interobserver reproducibility in deriving cardiac output by measuring aortic blood flow velocity and diameter with imaging and Doppler ultrasound was investigated in 20 healthy infants born at full term. Aortic diameter was measured in three ways. Mean blood flow velocity was measured at three sites with both continuous wave and pulsed Doppler. Two observers carried out each study independently. Intraobserver reproducibility was investigated in 12 infants using the suprasternal site for measuring blood flow velocity. The most reproducible determination of cardiac output was found when the suprasternal site with continuous wave Doppler was used for measurement of blood flow velocity and M mode trailing edge to leading edge echocardiography was used for diameter. Normal mean (2 SD) cardiac output is 231 (77) ml/kg/min. Technical difficulties in measuring aortic diameter accurately limit direct comparison between infants.

Cardiac Output↗
PubMed1989

Normal limits of the high-fidelity pediatric ECG. Preliminary observations.

A study of more than 1,780 neonates, infants, and children was carried out, using a digital electrocardiograph with a sampling rate of 500 per second, to revise the normal limits of the pediatric ECG. The 12-lead ECG was used with V4R replacing V3. All leads were recorded simultaneously off-line in digital form on magnetic tape and were subsequently analyzed using well-established computing techniques. The results showed that the upper 98 percentile limit of normal amplitudes could be up to 46% higher than previously published limits. Differences in some mean values were very much higher, though these are of less clinical significance. In addition, QRS durations were found to be wider than previously published data. Sex-related differences could be demonstrated in both amplitude and duration measurements, particularly in the early adolescent years. This study confirms that to record pediatric ECGs with high fidelity, it is necessary to use equipment that converts the ECG from analog to digital form at a rate of 500 samples/sec. Significant errors in amplitude and duration measurements may be expected if a much lower sampling rate is utilized.

Adolescent↗
PubMed1988

A comparison of isometric exercise, cold pressor stimulation and dynamic exercise in patients with coronary heart disease.

Isometric exercise and cold pressor stimulation have been proposed as alternatives to dynamic exercise in the evaluation of patients with coronary heart disease. We evaluated all three, by gated radionuclide ventriculography, in 13 male controls and 44 male patients with coronary heart disease. In controls, mean left ventricular ejection fraction did not change during isometric exercise or cold pressor stimulation (64 +/- 2 to 63 +/- 2 and 63 +/- 3) but fell significantly in patients (56 +/- 1 to 53 +/- 1 and 53 +/- 1, both P less than 0.001). During dynamic exercise, mean left ventricular ejection fraction rose in controls (64 +/- 2 to 84 +/- 2, P less than 0.001) but did not change in patients (56 +/- 1 to 56 +/- 2). There was considerable overlap between the groups in the left ventricular ejection fraction response to isometric exercise and cold pressor stimulation; only dynamic exercise discriminated between them. Isometric exercise and cold pressor stimulation are of little value in the diagnosis of coronary heart disease by radionuclide ventriculography.

Adult↗
PubMed1987

Cardiovascular effects of training for a marathon run in unfit middle aged men.

The effects of a 30 week exercise programme on serum lipid values, blood pressure, and cardiac function were assessed in a group of sedentary men aged 35-50 training for their first marathon. Mean serum cholesterol concentration (n = 33) fell by 12% from 6.54 (SE 0.18) to 5.76 (0.15) mmol/l (mean fall 0.78 mmol/l; 95% confidence interval 0.52 to 1.04 mmol/l), serum triglyceride concentration (n = 33) by 22% from 1.56 (0.17) to 1.21 (0.09) mmol/l (mean fall 0.34 mmol/l; 95% confidence interval 0.12 to 0.56 mmol/l), and mean blood pressure (n = 27) by 10% from 102 (2) to 92 (2) mm Hg (mean fall 10 mm Hg; 95% confidence interval 7 to 13 mm Hg). These changes were not explained by changes in body composition. Peak exercise left ventricular end diastolic volume (n = 16) increased with training; as a result of this and an increased exercise left ventricular ejection fraction peak exercise cardiac output increased from 19.9 (1.2) to 23.1 (3.0) l/min (mean rise 3.2 l/min; 95% confidence interval 1.5 to 5.0 l/min). Maximum oxygen consumption increased from 33.9 (1.6) to 39.0 (1.3) ml/kg/min (mean rise 5.0 ml/kg/min; 95% confidence interval 1.8 to 8.2 ml/kg/min). This study showed favourable effects on coronary risk factors and cardiac function and supports the place of regular exercise in coronary prevention programmes.

Blood Pressure↗
PubMed1987

A double blind placebo controlled comparison of verapamil, atenolol, and their combination in patients with chronic stable angina pectoris.

The efficacy and effect on cardiac function of verapamil 120 mg three times a day and atenolol 100 mg once a day, singly and in combination, were evaluated in 15 patients with angina pectoris. While they were on the combination treatment four patients withdrew from the study. Episodes of angina pectoris and glyceryl trinitrate consumption were significantly reduced only on the combination. On the combination only four patients developed evidence of ischaemia during exercise compared with seven on verapamil and ten on atenolol. ST segment depression at peak exercise, assessed by 16 point precordial mapping, was reduced by all active treatments from 7.1 on placebo to 2.7, 0.9, and 0.6 mm on atenolol, verapamil, and the combination respectively. Mean left ventricular ejection fraction fell significantly from 60% on placebo to 53% on the combination but was unchanged on verapamil and atenolol. Verapamil was an effective alternative to atenolol; the combination was the most effective treatment but was associated with a significant morbidity.

Aged↗
PubMed1987

A case-control study of possible causative factors in mycosis fungoides.

A detailed case control study was carried out on 53 patients (33 males and 20 females) with histologically proven mycosis fungoides and on an age- and sex-matched control population. Possible causative factors investigated included occupation, recreation, and exposure to petrochemicals, pesticides, insecticides, and potential carcinogens. Exposure to plants of the Compositae family, tanning history, and chronic sun exposure were also investigated, as were smoking history, drug ingestion history, and other skin disease. Personal and family histories of other malignancies were also investigated. The only statistically significant difference to emerge was that the patients with mycosis fungoides had significantly more family history of atopic dermatitis. In view of the absence of any significant difference between patients and controls with regard to personal history of atopic dermatitis, this difference may be the result of multiple statistical testing rather than a phenomenon of true biological significance.

Adolescent↗
PubMed1986

Is homoeopathy a placebo response? Controlled trial of homoeopathic potency, with pollen in hayfever as model.

The hypothesis that homoeopathic potencies are placebos was tested in a randomised, double-blind, placebo-controlled trial. The study model chosen compared the effects of a homoeopathic preparation of mixed grass pollens with placebo in 144 patients with active hayfever. The homoeopathically treated patients showed a significant reduction in patient and doctor assessed symptom scores. The significance of this response was increased when results were corrected for pollen count and the response was associated with a halving of the need for antihistamines. An initial aggravation of symptoms was noted more often in patients receiving the potency and was followed by an improvement in that group. No evidence emerged to support the idea that placebo action fully explains the clinical responses to homoeopathic drugs.

Adolescent↗