The effect of adenosine on histamine release from rat peritoneal mast cells induced by the calcium ionophore in buffers containing different calcium concentrations.
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Adenosine↗
Biomedical subjects
J MacMahon
Publications and source records attributed to J MacMahon.
Death from airways obstruction: accuracy of certification in Northern Ireland.
BACKGROUND: Studies of mortality from asthma and chronic obstructive pulmonary disease (COPD) have relied on death certification or registration for case finding. The aim of this study was to determine the accuracy of death certification and registration in asthma and COPD. METHODS: All death certificates in Northern Ireland for 1987 where asthma or COPD (defined as International Classification of Diseases 9th Revision (ICD9) 490, 491, 492, 496) were listed in part I or part II were identified. The following certificates were then selected for further investigation: those mentioning asthma for all ages, those mentioning COPD for ages less than 56 years, and a 50% sample of those mentioning COPD aged 56-75 years. For these selected deaths the general practitioners' case notes, hospital records, and necropsy findings were reviewed. Questionnaires detailing the clinical history and circumstances of death were completed by the general practitioner by post and by a close relative or associate of the deceased (doctor administered) if, after initial investigation, the death was likely to be due to COPD or asthma. A panel of two respiratory physicians reviewed each death and, using clinical diagnostic criteria, assessed the accuracy of the registered cause of death. RESULTS: Of 50 registered asthma deaths 43 were confirmed as being due to asthma. In nine registered deaths from COPD in cases aged less than 56 years one was confirmed as COPD, two as asthma, and six as other respiratory conditions. Of 105 registered deaths from COPD in cases aged 56-75, 42 were confirmed as COPD, 27 as asthma, eight as other respiratory conditions, and 28 as other causes. Although few errors in registration were found, 21% of certificates mentioning asthma and 38% of certificates mentioning COPD but not asthma in part I were subject to variable application of the classification rules by the registering officers. For all deaths under 75 years of age in Northern Ireland in 1987 where either asthma or COPD was mentioned anywhere on the death certificate, the estimated sensitivity and specificity of the registered cause of death in predicting the "true" cause of death were 29% and 98.6% for asthma and 69% and 70% for COPD. CONCLUSIONS: In a population of subjects where asthma or COPD was mentioned anywhere on the death certificate, the registered cause of death is a relatively poor indicator of the "true" cause of death for both asthma and COPD. Variation occurred in the application of death classification rules by registration officers. Many deaths certified and registered as COPD could have been called asthma using current standards of clinical diagnosis. In studies investigating risk factors for deaths from asthma, case finding should consider deaths registered as COPD.
Aged↗
Home ventilation in Northern Ireland.
Thirteen patients were identified as receiving assisted ventilation at home in Northern Ireland in 1994. Two patients have since died. An increasing number of patients are starting home ventilation, especially by nasal mask. Recognition of the needs of these patients and provision of care require further consideration.
Adolescent↗
Pharyngeal sensation and gag reflex in healthy subjects.
The gag reflex is often used in the assessment of swallowing, yet its absence does not predict aspiration in acute stroke. Disordered pharyngeal sensation has been found to be a sensitive predictor. The occurrence of gag reflex and pharyngeal sensation in healthy people is unknown. We studied these tests in 140 healthy subjects (half elderly and half young). Gag reflex was absent in 37% of subjects whereas pharyngeal sensation was absent in only 1. The results largely explain the low predictive value of gag reflex in the assessment of aspiration in acute stroke. Testing pharyngeal sensation would be more likely to be useful in these circumstances.
Adult↗
Transplantation for chronic pulmonary disease: referral and outcome in Northern Ireland, 1986-1990.
Eighteen patients have been referred for lung transplantations from Northern Ireland in 1986-1990. Fourteen were accepted but only four achieved transplantation. These rates are lower than for comparable regions in the North of England. The lung donation rate from Northern Ireland during the same period was similar to that for the United Kingdom as a whole. The low referral and transplant rates for Northern Ireland require reassessment of the procedures involved.
Heart-Lung Transplantation↗
The natural history and clinical consequences of aspiration in acute stroke.
Sixty consecutive patients admitted to a teaching hospital with acute stroke were studied prospectively for 3 months to define the natural history and consequences of lung aspiration. Using videofluoroscopy, aspiration was identified in 25 patients (42%) within 72 h of stroke onset, and had resolved in all but three patients (8%) after 3 months. It was closely related to the presence of dysphagia, which itself resolved within 2 weeks in all but the persistent aspirators. Lower respiratory tract infection (LRTI) was more common in aspirating patients (68%) than non-aspirators (6%). The use of intravenous fluids without oral intake did not appear to prevent LRTI in aspirating patients who were also dysphagic. Pneumonia occurred after 2 weeks in the three patients subsequently found to aspirate persistently. Aspiration is a transient phenomenon in most cases of acute stroke; it is associated with a high incidence of LRTI, but mortality in this series was not significantly associated either with respiratory tract infection or aspiration itself.
Aged↗
Improved harness crutch to reduce upper limb effort in swing-through gait.
A novel crutch, the harness crutch, is described which reduces loading on the arms during the swing phase of swing-through gait. The device was fabricated by attaching a modified mountaineering harness by two side straps, to modified axillary crutches. The harness crutch was compared with the saddle crutch, described by Taylor in 1883. The saddle crutch produced pressures in excess of 500 mmHg in the perineal area; no pressures were produced in this area with the harness crutch. Ischial pressures produced by both systems were similar. In six out of eight non-impaired subjects, significantly more force was transmitted to the harness crutch (an average 47% of body weight) than to the saddle crutch (an average 40% of body weight). A comparison of the oxygen cost of swing-through gait was made between the harness crutch and unmodified axillary crutches; with the harness crutch oxygen cost was significantly lower (p < 0.01) and there were no significant differences in speed and stride length.
Arm↗
Asthma mortality and death certification in Northern Ireland.
BACKGROUND: Asthma mortality has been rising in many western countries for largely unknown reasons. One cause could be change in certification practice. This study was designed to investigate the accuracy of death certification in Northern Ireland for the years 1981-4 and, in addition, to assess the reliability of trends observed in asthma death registration from 1957 to 1985. METHODS: The following death certificates were obtained for the years 1981-4: those mentioning asthma (all age groups), chronic obstructive airway disease, emphysema, or chronic bronchitis, but only where the decreased was 55 years or less. Information was collected from medical records, questionnaires to the general practitioner, and interviews with a close relative of the decreased. Death as a result of asthma was confirmed or otherwise by a panel and the confirmed deaths were compared with those registered. The numbers of deaths from asthma for the years 1957-85 were obtained from the offices of the Northern Ireland Registrar General. RESULTS: A total of 174 deaths from asthma was identified; 123 (70.7%) had been registered, while the remainder had been coded under another diagnosis. The annual number of confirmed deaths differed little from the figures of the Registrar General. A sharp increase in the annual number of deaths from asthma was observed, beginning in 1977, following a decline in the mid 1970s. CONCLUSIONS: During the years 1981-4 death certification for asthma was found to be inaccurate. The number of false positive registrations was balanced by the number of false negatives, suggesting that the registered totals reflect actual asthma mortality.
Adolescent↗
Sleep related hypoxaemia in hypertensive and normotensive men.
BACKGROUND: An association between hypertension and obstructive sleep apnoea (OSA) has been found by some researchers but remains controversial. Since such an association would have important implications for the investigation and management of hypertension, the rate of nocturnal hypoxaemic episodes has been compared in hypertensive and normotensive men. METHODS: The study was carried out in the community in Belfast and its environs. Thirty four men with mild to moderate hypertension aged 40-64 years were identified from general practice and a hypertension clinic. Normotensive men, matched for age and body mass index, were selected from a community survey. Subjects answered a sleep questionnaire and underwent overnight pulse oximetry at home. Computer analysis of the results gave the number and magnitude of dips in oxygen saturation (SaO2 dips, 4% or greater). RESULTS: The median number of SaO2 dips/hour for hypertensives was 2.0, and for normotensives was 0.8. Lowest SaO2 and mean SaO2 levels were significantly lower in the hypertensive group. Only one subject had a rate of SaO2 dips/hour greater than five and symptoms suggestive of OSA. CONCLUSIONS: Both hypertensive and normotensive men had relatively few episodes of nocturnal hypoxaemia. The small increase in the rate of SaO2 dips in hypertensive subjects has not yet been fully explained. These results imply that OSA is not common in hypertensive subjects and is unlikely to be an important cause of hypertension.
Humans↗
Aspiration in acute stroke: a clinical study with videofluoroscopy.
To assess the incidence of lung aspiration in acute stroke, and attempt to identify factors which render such patients at risk of aspiration, consecutive patients admitted to hospital within 24 h of their first symptomatic stroke were studied prospectively. Sixty patients who were conscious, and who did not have any preceding neurological or other cause of dysphagia, were assessed clinically and underwent a bedside water-swallowing test and videofluoroscopy within 72 h of stroke. Twenty-five patients (42%) were seen to aspirate at videofluoroscopy; of these 20% did not have overt dysphagia as detected by a simple water-swallowing test. Factors found to be significantly associated with aspiration were reduced pharyngeal sensation, dysphagia and stroke severity. Aspiration is common in the early period following acute stroke; disordered pharyngeal sensation is an important concomitant of this and should be carefully tested in each patient admitted with acute stroke.
Aged↗
Trends in the prevalence of asthma and dyspnoea in first year university students, 1972-89.
The prevalence of asthma and dyspnoeic symptoms were studied in undergraduates from Ireland, north and south, entering Queen's University Belfast in the years 1972, 1978, 1983, 1986 and 1989. The records of students' compulsory entry medical examination, including responses to questions on dyspnoeic symptoms in a health screening questionnaire, were reviewed. Between 1972 and 1989, the 12-month period prevalence of asthma increased from 1.3% to 2.84% (p < 0.001). This increase was not accounted for by the changes in the sex, or socioeconomic structure of the student body. In non-asthmatics the prevalence of dyspnoea rose from 5.49% to 8.30% (p < 0.01). In students with diagnosed asthma, the proportion with dyspnoeic symptoms did not significantly increase (p = 0.167). There was a greater than two-fold increase in the prevalence of diagnosed asthma in this population between 1972 and 1989. The prevalence of asthma was higher in rural than in urban students. There was also an increased reporting of dyspnoea in non-asthmatics, the significance of which is unclear.
Adolescent↗
The effects of flosequinan on hemodynamics and oxygen delivery in cor pulmonale.
The hemodynamic effects of a new orally active vasodilator, flosequinan, were compared with placebo (single blind) over 24 h in eight patients with pulmonary hypertension secondary to severe chronic obstructive pulmonary disease. Mean pulmonary artery pressure was reduced by 5.1 (3.4, 6.7) mm Hg (mean 95 percent CI) (p < 0.003) and pulmonary vascular resistance was reduced by 70 (23, 189) dynes.s.cm-5 (p < 0.013) by active drug compared with placebo. Cardiac output increased significantly with flosequinan by 0.47 (0.03, 0.91) L/min (p < 0.04) and systemic oxygen delivery increased by 90 (50, 120) ml/min/m2) (p < 0.05). A significant reduction in systemic vascular resistance was observed, 132 (35,230) dynes.s.cm-5 (p < 0.02) but no significant changes were seen in systemic arterial blood pressure or arterial blood gas tensions. Flosequinan favorably altered pulmonary hemodynamics relative to systemic and resulted in a significant improvement in oxygen delivery. The hemodynamic and blood gas effects of this compound suggest that it is a promising vasodilator for the treatment of pulmonary hypertension.
Adult↗
Local anaesthesia for fibreoptic bronchoscopy.
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Anesthesia, Local↗
Cardiopulmonary exercise testing in the pre-operative assessment of patients for repair of abdominal aortic aneurysm.
We have investigated the value of cardiopulmonary exercise testing in the pre-operative assessment to patients for abdominal aortic aneurysm repair. Thirty-six patients were entered into the study. All had a pre-operative clinical assessment and investigations including chest radiograph, electrocardiograph, spirometry and echocardiogram with measurement of left ventricular ejection fraction. Each patient performed a symptom limited treadmill exercise test using a STEEP protocol with on-line measurement of respiratory gas exchange. Patients were followed up for 12 months post-operatively by review of casenotes. Thirty out of 36 patients had surgical repair of abdominal aortic aneurysm. There was 1 death in the perioperative period and 2 deaths in the following 12 months. Seven other patients suffered post-operative complications. There were no significant differences in left ventricular ejection fraction, spirometry and peak achieved oxygen consumption (PVO2) between those patients who died or who had post-operative complications and those who had not. However, PVO2 < 20 ml/min/kg was found in 70 per cent of patients who had complications compared with 50 per cent of those who had not. Also 4 patients considered medically unfit for surgery all had PVO2 < 20 ml/min/kg. Cardiopulmonary exercise testing with measurement of PVO2 may be helpful in identifying patients more at risk of post-operative complications but should not be used in isolation without through clinical assessment.
Aged↗
Stenting and superior vena caval syndrome.
The use of intravascular stents in the management of Superior Vena Caval Obstruction is a relatively recent development. We describe our experience with six patients, aged between 64 and 85 years who developed SVC obstruction secondary to malignant disease and who had one or more intravascular stents inserted. Five of the patients had lung cancer and one metastatic breast carcinoma. Positive histology was available in three cases. A partial or complete clinical response was seen in all patients and two patients developed recurrent symptoms. Stenting appears to provide effective palliation of SVC obstruction symptoms.
Aged↗
Effect of once weekly pulmonary rehabilitation on exercise tolerance in patients with chronic lung disease.
BACKGROUND: Pulmonary rehabilitation (PR) programmes improve exercise tolerance and reduce breathlessness in patients with chronic obstructive pulmonary disease. AIM: A retrospective audit was undertaken to assess the effectiveness of the pulmonary rehabilitation programme at Belfast City Hospital (BCH). METHODS: Data from 74 patients who completed a six-week PR programme were reviewed. Exercise tolerance was assessed by the shuttle walk test (SWT), and breathlessness by the BORG scale. Paired t-tests were used for within group analysis. RESULTS: The mean (SD) exercise tolerance assessed by the SWT improved significantly as did duration of individual exercises. Patients were able to exercise more without increasing their breathlessness or heart rate. CONCLUSIONS: This paper highlights the effect of PR on exercise tolerance and breathlessness in patients with chronic lung disease. The results compare favourably with published literature where more frequently supervised exercise sessions were provided.
Exercise Tolerance↗
The current physiotherapy management of patients with bronchiectasis: a UK survey.
The purpose of this survey was to ascertain which physiotherapy techniques are currently used, how interventions are assessed and to determine the views of physiotherapists in the UK on the need for further research. Senior physiotherapists in 100 randomly selected hospitals providing respiratory care in the UK were sent a previously piloted questionnaire on their bronchiectasis practice. The response rate was 82%. A variety of physiotherapy treatment techniques and outcome measures are used, and there are no national guidelines on the physiotherapy management of patients with bronchiectasis. There is a clear need for research into the effectiveness of physiotherapy techniques in bronchiectasis including a cost-benefit analysis which would enable targeting of resources and the development of evidence-based practice guidelines.
Attitude of Health Personnel↗
A retrospective survey of diagnosis and management of patients presenting with chronic cough to a general chest clinic.
Respiratory physicians often encounter patients with chronic cough. The evaluation and outcome of such patients by centres with established diagnostic protocols has been well described. By contrast, little is known about patients referred to general respiratory clinics where no such protocol exists. We describe the findings of a retrospective survey of all new patient referrals with chronic cough to a general respiratory clinic over a 12-month period. A diagnosis of asthma or chronic airflow obstruction was made in 43% of patients. Gastro-oesophageal reflux and postnasal drip syndrome, together accounting for over 60% of diagnoses in specialist clinics, were infrequently identified in our study (4% and 2% respectively). At follow-up, 43% of patients reported persistent symptoms, contrasting the excellent treatment response reported by specialist clinics. In general respiratory clinics where a specific diagnostic protocol is not in place, these differences in diagnosis and outcome may be due to inadequate investigation or may reflect a different patient population.
Adolescent↗