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Biomedical subjects

M B Allen

Publications and source records attributed to M B Allen.

At least 19 recordsLinked to original sources

Accuracy and significance of scoring hypopneas.

We previously reported that the best definition of hypopneas in the sleep apnea/hypopnea syndrome (SAHS) is based on reduction in thoracoabdominal movement. However, the repeatability of scoring hypopneas from thoracoabdominal movement has not been assessed, nor has the need to record flow as well as thoracoabdominal movement. Thus, two polysomnographers independently scored both apneas and hypopneas on all-night polysomnograms of patients with SAHS. There was close agreement between the polysomnographers for the number of hypopneas (r = 0.98; mean difference 11%) and for the number of apneas (r = 0.99; mean difference 8%). The agreement was similar for the durations of both hypopneas (r = 0.99; mean difference 13%) and apneas (r = 0.99; mean difference 11%). There was also close agreement between the total number of respiratory events scored with and without reference to the flow signal (r = 0.99; mean difference 1.4%) with a maximum under-recognition of 18 events per night in a subject with 237 apneas per night. Thus, hypopneas can be scored reproducibly. In addition, the value of always recording and scoring flow as well as thoracoabdominal signals is questioned.

Adult

Salmeterol rash.

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Adrenergic beta-Agonists

Obstructive sleep apnoea in adults presenting with snoring.

Snoring is a common disorder, and may be associated with obstructive sleep apnoea, although there is little published information on the incidence of apnoea in snorers. This study aimed to assess the upper airway and to relate the findings to sleep study data in a population of patients referred by their general practitioners with loud snoring. Each patient had a full history, weight and height measurements, nasal examination, rhinomanometry, peroral grading of the oropharyngeal features, and fibreoptic pharyngoscopy with a modified Muller manoeuvre, followed by a sleep study. The results in our group of 35 patients demonstrate a high incidence of obstructive sleep apnoea (46%). Factors which correlated well with apnoea were excessively loud snoring, a narrow oropharynx, and marked obesity; 94% of patients with one or more of these features had evidence of sleep apnoea.

Adult

Chemosensitivity testing of human gliomas using a fluorescent microcarrier technique.

This report describes a new fluorescent microcarrier cytostasis assay. Human glioma cell lines and primary cultures were attached to microcarrier tissue culture beads and treated with various chemotherapeutic drugs. After treatment, the cells were labelled with two vital fluorescent dyes in order to measure cellular viability. The uptake of hydroethidine and Hoechst 33342 was evaluated alone and in combination as probes for determining metabolic activity and cellular proliferation. Hydroethidine was found to be superior when compared to trypan blue and tritiated thymidine. The use of the microcarrier technique allows for the direct cellular measurement of fluorescence without the need of extensive extraction procedures. The fluorescent assay is a sensitive, rapid and an effective way to screen for potential antiproliferative compounds.

Antineoplastic Agents

The use of probenecid to increase the serum amoxycillin levels in patients with bronchiectasis.

Amoxycillin 3 g twice daily is effective in treating patients with bronchiectasis who have daily purulent sputum. However, it is a relatively expensive treatment if used for prolonged periods. This pilot study in six patients with bronchiectasis showed that the concurrent administration of probenecid with a smaller dose of amoxycillin produced similar clinical responses and pharmacokinetic profiles to those found with high dose amoxycillin alone. The amount of amoxycillin used was reduced by two thirds, producing a potential saving of approximately pound 1000 per patient per annum in those taking long term treatment.

Adult

How well do the general public read Heaf skin tests?

The ability of 550 consecutive patients attending a tuberculosis clinic to grade their own Heaf skin test reaction, using an illustrated card designed for such self-reporting, was assessed. Individuals were asked to grade their own Heaf skin reaction and at the same attendance the reaction was formally graded by a respiratory health visitor. There was overall excellent agreement with only 58 (10.5%) disparate gradings. We conclude that self-reporting of Heaf skin tests using an illustrated card is simple, usually accurate and may preclude an otherwise unnecessary early reattendance. This study also validates an often used system of self-reporting.

Adolescent

Optimal duration of radiological follow-up for tuberculosis contacts.

Eight hundred and sixty Heaf test positive contacts of cases of tuberculosis in Lothian were offered screening with chest radiographs for the recommended period of two years. In spite of the use of standard methods of encouragement to attend, only 309 (35.9%) completed the two year period of follow-up. Seven cases of tuberculosis (representing a crude rate of eight cases per 1000 contacts) were detected radiologically, all within 3 months of entering the screening programme. In view of the poor compliance with the extended period of follow-up and the detection of all cases early in the screening process, we recommend that, at least in Lothian, radiological follow-up of Heaf positive tuberculosis contacts need only be applied for a period of 6 months.

Adolescent

Respiratory symptoms and pulmonary impairment in male and female subjects with pottery workers' silicosis.

Respiratory symptoms, smoking habit, lung function and radiological category of silicosis were assessed in 276 present and former pottery workers who were receiving industrial disablement benefit for silicosis. There were 140 females and 136 males. The proportion with conglomerate disease (massive fibrosis) was similar in both sexes. The FEV1 declined with increasing X-ray category of silicosis irrespective of smoking habit and was most marked in subjects with symptomatic chronic bronchitis. In females who had never smoked the average decline of FEV1 in those with simple silicosis was 18 ml year-1 and for those with conglomerate disease 38 ml year-1. Symptomatic chronic bronchitis was common and only partly related to smoking, occurring in 69% of 101 nonsmoking female silicotic patients. No significant changes were observed in vital capacity, lung volume or transfer factor for carbon monoxide.

Aged

Peripheral nerve function in patients with chronic bronchitis receiving almitrine or placebo.

A double blind prospective study of the effect of almitrine bismesylate and placebo on peripheral-nerve function was carried out in 12 patients with chronic bronchitis and arterial hypoxaemia (mean (SD) FEV1% predicted 38 (16), arterial oxygen tension (PaO2) 7.56 (0.76) kPa). Of the seven patients who took placebo, none developed symptoms or signs of peripheral neuropathy. One patient who had abnormal lower limb sensory nerve conduction initially showed improvement of sensory conduction but deterioration in motor conduction during the 12 month study period. Two further patients developed some slowing of motor conduction velocities in their right lateral popliteal nerve. Five patients received almitrine and all showed an improvement in PaO2 (mean from 7.0 to 7.9 kPa). None had symptoms or signs of peripheral neuropathy on entry to the study; one patient had evidence of impaired nerve conduction on electrophysiological testing. Three patients developed symptoms and signs of peripheral neuropathy during the 12 months of the study and a fourth developed peripheral neuropathy at 18 months, having continued to receive almitrine. Studies of nerve physiology showed abnormalities in the lower limbs of all four patients. Recovery was poor, possibly because of the long half life of almitrine. The studies suggest that almitrine may precipitate peripheral neuropathy in patients with chronic obstructive pulmonary disease. Patients should be warned of this potential complication so that the drug can be stopped as soon as symptoms develop.

Aged

Hypercalcemia in atypical bronchial carcinoid tumors.

Atypical carcinoid tumors of the bronchial tree are uncommon. Their tendency to metastasize is well recognized, characteristically producing osteoblastic bone deposits without disturbance of calcium homeostasis. We report two patients who presented with hypercalcemia and osteolytic bone metastases following surgical removal of atypical bronchial carcinoid tumors. In one of the patients, chemotherapy induced remission and controlled the hypercalcemia.

Aged