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Biomedical subjects

C F Stanford

Publications and source records attributed to C F Stanford.

At least 37 records · Page 2Linked to original sources
PubMed1992

Oxygen consumption during corridor walk testing in chronic cardiac failure.

We have examined the use of a 6-min corridor walk test in the assessment of functional capacity in 16 patients with chronic cardiac failure. VO2 was determined concurrently by a portable 'Oxylog'. Three tests were performed sequentially, and although there was a significant increase in distance walked and highest VO2 achieved between the first and second tests, good reproducibility was attained between the second and third tests. Both walk test variables correlated well with previously determined peak achieved VO2, and NYHA classes were separated adequately. Corridor walk testing, with or without measurement of VO2 should be a useful adjunct to maximal exercise testing in interventional studies.

Aged↗
PubMed1992

Comparative effects of epanolol and diltiazem on exercise performance and respiratory gas exchange in angina pectoris.

The effects of epanolol (a new selective beta-adrenoceptor antagonist), diltiazem and placebo were compared in a group of 16 patients with chronic stable angina pectoris. Each patient received each treatment in random order. Diltiazem reduced weekly angina attack rate from 7.2 (95% CI 3.9-10.5) to 3.9 (1.9-5.9) (P less than 0.01), whereas a lesser reduction was observed after epanolol. Both drugs produced a small but significant (P less than 0.05) increase in treadmill exercise time (placebo 474 s (374-574), epanolol 527 s (431-623) and diltiazem 554 s (462-646). However, aerobic work capacity, assessed by peak achieved oxygen consumption, was not different from the placebo value of 21.2 (18.0-24.4) ml.min-1.kg-1, and clearly subnormal when compared to age- and sex-matched controls (33.0 (30.1-35.9) ml.min-1.kg-1). Ventilatory abnormalities and increased lactate levels on active treatment were observed at peak exercise only. We conclude that the cardiodepressant effects of both active drugs limit blood supply to working skeletal muscle, and that chest pain may be replaced by dyspnoea or fatigue as the limiting factors to exercise.

Adrenergic beta-Antagonists↗
PubMed1992

A pharmacokinetic and pharmacodynamic comparison of plain and enteric-coated prednisolone tablets.

1. Eight healthy volunteers and eight patients suffering from chronic obstructive pulmonary disease (COPD) received 30 mg prednisolone as plain (P) and enteric-coated tablets (EP) in a randomised, cross-over manner. Plasma prednisolone and cortisol and blood glucose were measured over 24 h. 2. Although absorption of prednisolone was considerably slower when administered as the enteric-coated form, peak plasma drug concentrations and total AUC (0,24 h) were equivalent for the two formulations. Malabsorption of prednisolone was not observed. 3. The administration of EP was associated with significantly less adrenal suppression in volunteers than P as judged by measurement of AUC (0,24 h) values for endogenous cortisol. However, this difference did not reach statistical significance in the patient group. 4. Plasma cortisol concentrations declined more slowly following administration of the enteric-coated form to both groups. The difference in time taken (median and range) to maximum suppression of cortisol was statistically significant (P less than 0.05) between P (2.5 h; 2-4 h) and EP (4 h; 3-12 h) preparations administered to volunteers. There was a similar significant difference (P less than 0.05) between P (2.5 h; 1-4 h) and EP (7 h; 2-12 h) in the patients. 5. Plasma cortisol concentrations were significantly lower at 24 h in patients receiving the enteric-coated product in association with higher terminal prednisolone concentrations. 6. Blood glucose concentrations increased over an 8 h period in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The effects of diuretics on nasal transmucosal potential difference.

The effects of application of frusemide, amiloride and bumetanide on nasal transmucosal potential difference (NTPD), at rest and during exercise, were studied in 8 normal subjects. In a double-blind placebo controlled study, 8 volunteers had NTPD recorded at 4-min intervals during 12-min periods of rest, before and after treatment, during 12 min of exercise, and recovery. Application of placebo, frusemide and bumetanide did not significantly alter NTPD at rest. Amiloride caused a significant reduction (P less than 0.025). During exercise there was a significant rise in NTPD with placebo (P less than 0.05), frusemide (P less than 0.05) and amiloride (P less than 0.05). There was no increase in NTPD during exercise with bumetanide.

Adult↗
PubMed1992

Comparison of immunodiffusion and enzyme linked immunosorbent assay in the detection of abnormal antibodies in pigeon breeder's disease.

AIMS: To compare the sensitivity of two methods for the detection of serum antibodies to pigeon faecal antigens in patients with pigeon breeder's disease. METHODS: Serum samples stored at -20 degrees C from 50 patients with pigeon breeder's disease, 50 control samples from patients with other respiratory diseases, and 50 healthy blood donors were examined for the precipitating antibodies and IgG antibodies to antigens present in extract of pigeon droppings by immunodiffusion and enzyme linked immunosorbent assay (ELISA), respectively. RESULTS: Both antigen preparations of pigeon dropping extract were equally effective. A positive immunodiffusion reaction gave one or more precipitin lines and these antibodies were detected only in undiluted sera from 80% of the patients with pigeon breeder's disease. In the ELISA the sera were tested at a starting dilution of 1 in 100 because positive reactions were observed with sera from healthy blood donors at lower dilutions. All sera which gave optical density readings above 3 SD of the control value were considered to have IgG antibodies. These antibodies were detected in sera from all the patients with pigeon breeder's disease. The antibody titres were much higher in those patients who had precipitating antibodies (range 800-51,200) than those without (range 100-800). The antibodies were not detected in the sera of patients with respiratory diseases or healthy blood donors by either method. CONCLUSIONS: Antibodies to pigeon dropping antigens were detected by immunodiffusion and ELISA in sera from patients with pigeon breeder's disease but not in control sera. ELISA was a more sensitive method for detecting antibodies and therefore seems to have considerable potential as a routine technique in the serological diagnosis of pigeon breeder's disease.

Adolescent↗
PubMed1992

Lung function testing in adults with preferential nasal breathing.

Three adult patients with asthma with preferential nasal breathing were found to have a typical pattern of lung function test results with substantial between test variation. This condition can be identified as a cause of unsatisfactory performance in respiratory tests by observing the patient's reaction after the nostrils have been occluded.

Aged↗
PubMed1992

The parasympathetic system in exercise-induced rhinorrhoea.

The present study demonstrates that ipratropium bromide significantly reduces normal resting nasal secretion (p less than 0.05) and also significantly reduces exercise induced rhinorrhoea compared with a placebo (p less than 0.01). It also demonstrates that there may be another non-parasympathetic cause for the increase in nasal secretion with exercise.

Adult↗
PubMed1991

Resting energy expenditure in chronic cardiac failure.

1. Resting energy expenditure has previously been shown to be elevated in the acute phase of heart failure, but the situation in the compensated state of chronic cardiac failure is unclear. Resting energy expenditure was assessed in 14 patients with stable chronic cardiac failure and 14 matched control subjects by using indirect calorimetry. 2. Resting energy expenditure was significantly elevated in the patients with chronic cardiac failure (112.6 +/- 18.1 versus 87.1 +/- 12.2 kJ day-1 kg-1 total body weight, P less than 0.0002; mean +/- SD) as were resting O2 consumption (3.88 +/- 0.64 versus 3.00 +/- 0.43 ml min-1 kg-1, P less than 0.0002), ventilation (164 +/- 40.3 versus 104 +/- 16.2 ml min-1 kg-1, P less than 0.0001) and heart rate (85.8 +/- 16.9 versus 66.6 +/- 6.9 beats/min, P less than 0.001). Both the resting plasma concentration of noradrenaline (4.48 +/- 1.52 versus 2.28 +/- 0.96 nmol/l, P less than 0.0001) and the serum concentration of free fatty acids (0.78 +/- 0.21 versus 0.57 +/- 0.27 mmol/l, P less than 0.03) were greater in the patients with chronic cardiac failure. Analysis of covariance indicated that most of the difference in resting energy expenditure could be accounted for by the elevated ventilation in the patients with chronic cardiac failure. Arm muscle area, an index of wasting, was lower in the patients with chronic cardiac failure (39.1 +/- 13.1 versus 50.5 +/- 9.4 cm2, P less than 0.02) and resting energy expenditure was found to account for some of this difference. 3. We conclude that an elevated basal metabolism occurs in chronic cardiac failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Magnesium status and digoxin toxicity.

1. Eighty-one hospital patients receiving digoxin were separated into groups with and without digoxin toxicity using clinical criteria. Serum digoxin, sodium, potassium, calcium, creatinine, magnesium and monocyte magnesium concentrations were compared. 2. Subjects with digoxin toxicity had impaired colour vision (P less than 0.0001, Farnsworth-Munsell 100 hue test) and increased digoxin levels (1.89 (1.56-2.21) vs 1.34 (1.20-1.47) nmol l-1, P less than 0.01) (mean (95% confidence limits], though there was considerable overlap between two groups. 3. Subjects with digoxin toxicity had lower levels of serum magnesium (0.80 (0.76-0.84) vs 0.88 (0.85-0.91) mmol l-1, P less than 0.01) and monocyte magnesium (6.40 (5.65-7.16) vs 8.76 (7.81-9.71) mg g-1 DNA, P less than 0.01), but there were no significant differences in other biochemical parameters. A greater proportion of toxic subjects were receiving concomitant diuretic therapy (20/21 vs 37/60, P less than 0.05). 4. Magnesium deficiency was the most frequently identified significant electrolyte disturbance in relation to digoxin toxicity. In the presence of magnesium deficiency digoxin toxicity developed at relatively low serum digoxin concentrations.

Adult↗
PubMed1991

Non-arterial assessment of blood gas status in patients with chronic pulmonary disease.

Assessment of blood gas status is important in the management of patients with chronic pulmonary disease. Arterial puncture is often painful and may damage the arterial wall. Measurement of oxygen saturation by transcutaneous oximetry offers a non-invasive alternative to arterial methods but does not allow assessment of partial pressure of carbon dioxide. We have examined the value of oximetry and dorsal hand venous carbon dioxide as an alternative to arterial puncture. Transcutaneous oxygen saturation correlated with arterial oxygen saturation (r = 0.76, p less than 0.001) with an error of 2.1% and dorsal hand venous carbon dioxide tension correlated with the arterial tension (r = 0.84, p less than 0.001) with an error of 8%. Changes in oximetric oxygen saturation and venous carbon dioxide tension following oxygen therapy reflected arterial values. Assessment of blood gas status using oximetry and dorsal hand venous carbon dioxide tension is a useful alternative to arterial puncture.

Aged↗
PubMed1990

Transcutaneous oxygen tension in the leg during exercise in patients with chronic cardiac failure.

The transcutaneous partial pressure of oxygen measured in the lower limb was compared in 16 patients with chronic cardiac failure and seven normal subjects. At rest, there was no significant difference between patients and normals. At peak exercise, the partial pressure of oxygen fell significantly in those in heart failure, whereas no change was observed in normal subjects. No changes in arterial oxygen saturation (oximetry) were observed. These changes are likely to reflect abnormalities of peripheral perfusion of the skin.

Blood Gas Monitoring, Transcutaneous↗
PubMed1990

Zoonotic infections in Northern Ireland farmers.

Evidence of past zoonotic infection was investigated serologically in randomly selected Northern Ireland farmers. The percentage of farmers with antibody was: Brucella abortus (0.7), Leptospira interrogans serovars (8.1), Borrelia burgdorferi (14.3), Toxoplasma gondii (73.5), Coxiella burnetii (28.0), Chlamydia psittaci (11.1) and Hantavirus (1.2). The results show that Northern Ireland farmers have been exposed in the past to zoonotic infections. It is not known if these infections contributed to ill health in farmers but it is now time for the health of farm workers and their medical services to be reassessed.

Adult↗
PubMed1990

Substrate utilization during exercise in chronic cardiac failure.

1. Skeletal muscle metabolism in chronic cardiac failure may be influenced by the many circulatory and neurohumoral adaptations in the condition. We investigated aerobic metabolism during exercise using indirect calorimetry in 15 patients with chronic cardiac failure and in 14 control subjects. Subjects exercised on a treadmill for 20 min at a steady-state submaximal workload. 2. Venous lactate levels were relatively constant throughout the exercise, although they were slightly greater in the patients with chronic cardiac failure than in the control subjects. The respiratory exchange ratio was lower in patients with chronic cardiac failure (0.777 +/- 0.021 vs 0.833 +/- 0.037, means +/- SD; P less than 0.0002, Mann-Whitney U-test). Relative fat utilization, expressed as a percentage of total energy expenditure, was therefore greater in patients with chronic cardiac failure (71.8 +/- 7.0 vs 54.1 +/- 12.3%, P less than 0.0005) and this was mirrored in a lower carbohydrate utilization (24.7 +/- 6.5 vs 43.3 +/- 12.1%, P less than 0.0002). Levels of free fatty acids, glycerol and noradrenaline were greater in patients with chronic cardiac failure. 3. We conclude that there is an increased reliance on fat, as opposed to carbohydrate, metabolism during exercise in chronic cardiac failure, and that this may relate to the elevated catecholamine and free fatty acid levels present. This may be a compensatory mechanism to preserve muscle glycogen stores, but as fat utilization is less efficient in terms of oxygen consumed, this shift may further impair exercise capacity.

3-Hydroxybutyric Acid↗
PubMed1990

Reproducibility of cardiopulmonary parameters during exercise in patients with chronic cardiac failure. The need for a preliminary test.

To examine the reproducibility of cardiopulmonary exercise testing in patients with heart failure, three consecutive tests were performed in 30 such patients. The first test underestimated treadmill exercise time by about 20% when compared with the second and third tests, which were not significantly different. Peak achieved VO2, VCO2 and VE were also less during the first test, but blood pressure, heart rate and respiratory rate responses were similar in the three tests. When cardiopulmonary exercise tests are used to assess functional capacity in either individual patients or groups (as in a therapeutic trial), at least two tests should be performed, as a single test is likely to underestimate exercise capacity.

Aged↗
PubMed1990

The effects of flosequinan on submaximal exercise in patients with chronic cardiac failure.

1. Twenty patients with moderate to severe chronic cardiac failure were entered into a double-blind parallel group study comparing flosequinan 100 mg daily with matching placebo. 2. After at least three prior exercise tests, cardiopulmonary parameters were assessed at rest and during submaximal exercise before and after 2 and 8 weeks of active drug or placebo. 3. Resting minute ventilation and respiratory rate were reduced by flosequinan compared with placebo, but oxygen uptake was unchanged. 4. Comparison of minute ventilation, carbon dioxide production and venous lactate levels at the end of the exercise stage approximating to 50% of peak oxygen uptake demonstrated significant reductions in the flosequinan group compared with placebo at week 2 and week 8 (P less than 0.05). 5. Flosequinan increased the oxygen uptake at anaerobic threshold from 13.2 +/- 2.8 ml min-1 kg-1 to 15.9 +/- 3.4 ml min-1 kg-1 at week 2 and 15.8 +/- 3.7 ml min-1 kg-1 at week 8. These increases were significant when compared with placebo (P less than 0.05). 6. We conclude that flosequinan improves submaximal exercise performance in patients with chronic cardiac failure, probably by enhancing skeletal muscle blood flow.

Adult↗
PubMed1990

Farmer's lung in Northern Ireland.

A total of 381 farmers in Northern Ireland were studied using a questionnaire, pulmonary function tests, and antibody levels to Micropolyspora faena to assess the incidence of farmer's lung. Twenty (4.9%) had a history of a previous diagnosis of farmer's lung by their doctor. Forty four (10.4%) had delayed onset symptoms compatible with farmer's lung, 32 (7.9%) had precipitant antibody, and 61 (15%) had raised antibody by the enzyme linked immunosorbent (ELISA) method. Restricted lungs were present physiologically in 40 (9.8%). A confirmation of delayed symptoms and precipitant antibody was present in seven (1.7%) whereas delayed symptoms and ELISA antibody was present in nine (2.2%). Using either antibody method only two (0.5%) had a combination of antibody to M faenae, delayed onset symptoms, and restricted pulmonary physiology.

Antibodies, Bacterial↗
PubMed1990

Circulating immune complexes in sarcoidosis, a clinical role for the Raji assay?

Many immunological abnormalities, including circulating immune complexes (CICs), have been described in patients with sarcoidosis. The relationship of these abnormalities to clinical states is uncertain. In 31 proven cases of sarcoidosis we used the Raji assay in the investigation of the relationship between disease activity and the presence of CICs. Circulating immune complexes (greater than 49 micrograms.ml-1) were found in 11 of 14 patients with evidence of recent significant disease deterioration, whereas only one of 17 patients with chronic stable sarcoidosis demonstrated CICs (p less than 0.001). At follow-up, it was found that eight of the 11 cases with active disease and detectable CICs had resolved clinically. Resolution was accompanied by normalization of CICs in seven and persistence in one. The remaining three patients did not improve clinically and continued to demonstrate CICs. Measurements of complement levels did not demonstrate any significant difference between the two groups of patients. It is concluded that elevated levels of CICs, as detected by the Raji assay, are commonly found in association with significantly deteriorating sarcoidosis, often normalize following disease improvement and, consequently, may have a useful clinical role as a marker of activity.

Acute Disease↗