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Biomedical subjects

I D Johnston

Publications and source records attributed to I D Johnston.

At least 19 recordsLinked to original sources
PubMed1992

Pulmonary function after spinal surgery for idiopathic scoliosis.

Respiratory function was assessed in 20 patients with idiopathic scoliosis undergoing spinal surgery (median age, 15 years; range, 11-34 years; median preoperative vital capacity, 67%; range, 28-109% predicted). Ten patients underwent anterior spinal surgery through a thoracotomy incision, seven of whom had posterior spinal surgery as a second-stage procedure. The other ten had posterior spinal surgery as their initial operation. Postoperatively, three patients had clinical evidence of respiratory complications. Daytime oxygen saturation was reduced throughout the first postoperative week, with no significant difference between anterior and posterior spinal surgery. Hypercapnia was unusual and generally mild. Vital capacity was reduced significantly 1 week after both anterior and posterior spinal surgery (P less than 0.05). The median vital capacity 1 week after anterior spinal surgery was 45% of preoperative values compared with 78% after posterior surgery (P less than 0.05). Inspiratory muscle strength, as assessed by sniff mouth pressure, was 56% of preoperative values 1 week after anterior spinal surgery (P less than 0.05) and 85% after posterior spinal surgery (not significant). Vital capacity, but not sniff mouth pressure, remained significantly reduced 6 weeks after surgery. Oxygen saturation should be monitored noninvasively during the first week after both anterior and posterior spinal surgery even in patients at low risk of developing respiratory complications.

Adolescent↗
PubMed1992

Respiratory disease in systemic lupus erythematosus: correlation with results of laboratory tests and histological appearance of muscle biopsy specimens.

BACKGROUND: In systemic lupus erythematosus, certain laboratory tests and evidence from muscle biopsy specimens of lymphocytic vasculitis reflect disease activity. A study was designed to determine if such indices predict respiratory lesions, and in particular whether the presence of vasculitis in quadriceps muscle reflects respiratory muscle function. METHODS: Twenty seven 27 patients with systemic lupus erythematosus were studied, ten of whom were consecutive untreated patients and 17 having clinically active disease and being treated. They were prospectively evaluated on the basis of erythrocyte sedimentation rate, lymphocyte count, C3 degradation products, quadriceps muscle biopsy, spirometry, lung volumes, carbon monoxide transfer factor, and mouth pressure during a maximal sniff. RESULTS: Lung function test results were abnormal in 12 patients. Vital capacity was reduced in seven, carbon monoxide transfer factor capacity in five, and mouth pressure was low (< 70% predicted) in ten. Lymphocytic vasculitis was seen in the muscle biopsy specimens of ten patients. No correlation was found between laboratory tests and lung function or mouth pressure, or between the presence of lymphocytic vasculitis and mouth pressure. In untreated patients, those with lymphocytic vasculitis had lower spirometric values. CONCLUSIONS: In systemic lupus erythematosus, evidence from muscle biopsy specimens of lymphocytic vasculitis is not predictive of impaired inspiratory muscle function as measured by mouth pressure. In untreated patients there were relationships between some laboratory test results and respiratory function, but this was not the case for the whole group. In systemic lupus erythematosus, laboratory tests and evidence from muscle biopsy specimens of lymphocytic vasculitis are therefore unlikely to be helpful in the assessment of respiratory disease.

Adult↗
PubMed1992

Dressler's syndrome presenting as acute pneumonitis.

An elderly man developed acute pneumonitis three weeks after a myocardial infarction treated with streptokinase. The differential diagnoses are discussed and a short review of lung disease in the post-myocardial infarction syndrome is presented.

Acute Disease↗
PubMed1991

Accuracy of diagnostic coding of hospital admissions for cryptogenic fibrosing alveolitis.

To determine the accuracy of diagnostic coding of cryptogenic fibrosing alveolitis, the case notes of 166 admissions to four hospitals were reviewed. These consisted of all admissions that had been coded as "idiopathic fibrosing alveolitis" (ICD code 516.3: 97 admissions) or as "postinflammatory pulmonary fibrosis" (ICD code 515.9: 69 admissions). Of 88 available records of admissions coded as idiopathic fibrosing alveolitis, 70 (80%) patients had definite cryptogenic fibrosing alveolitis, and six (7%) possible cryptogenic fibrosing alveolitis according to predetermined conventional clinical criteria. Only seven (8%) admissions were clearly coded wrongly. Sixty four records were available for patients coded as having postinflammatory pulmonary fibrosis; 16 (25%) of these patients had definite cryptogenic fibrosing alveolitis, a further 12 (19%) had possible cryptogenic fibrosing alveolitis or fibrosing alveolitis with a connective tissue disorder, and the remainder had a very wide range of diagnoses. In this study the idiopathic fibrosing alveolitis (ICD 516.3) code was relatively reliable, but a substantial proportion of admissions coded under postinflammatory pulmonary fibrosis (ICD 515.9) also had cryptogenic fibrosing alveolitis and code 515.9 was of little diagnostic value. The data are inadequate for case finding, though in respect of cryptogenic fibrosing alveolitis may be adequate for planning purposes. There continues to be a need for more medical input into the process of diagnostic coding.

Connective Tissue Diseases↗
PubMed1991

Comparison of the diagnostic yields of disposable and reusable cytology brushes in fibreoptic bronchoscopy.

Disposable rake and reusable bristle type cytology brushes have been compared in 50 patients undergoing fibreoptic bronchoscopy for suspected malignancy. Forty seven patients were eventually found to have carcinoma of the bronchus. A diagnosis of malignancy was made from the specimens taken with one or other brush in 34 patients, from the reusable brush in 28, and from the disposable brush in 31. The specimens taken with the two types of brush were of similar quality. The reusable brush is about five times less expensive per procedure but carries a risk of cross contamination and cross infection, and time is needed to clean the brush after each bronchoscopy. The diagnostic yield appears to be at least as good with the disposable brush.

Adult↗
PubMed1991

Dilemmas facing surgical research in the '90s.

Surgical research in the '90s will need to address several general problems. This paper discusses the role of informed consent in clinical trials, animal experimentation in surgical research, and the importance of research in both undergraduate and postgraduate education.

Animal Testing Alternatives↗
PubMed1990

Theophylline in the management of airflow obstruction. 2. Difficult drugs to use, few clinical indications.

The narrow therapeutic index, potential toxicity, and need to monitor plasma concentrations make theophyllines difficult to use. Other drugs provide comparable or better bronchodilator and prophylactic efficacy. In asthma theophyllines should be considered for chronic stable asthma when treatment with optimal doses of inhaled steroids and bronchodilators fails to provide adequate control; for nocturnal asthma; and for prophylaxis and relief of symptoms in children and adults when inhaled treatment cannot be given. In general, theophyllines cannot be recommended for chronic airflow obstruction. A trial of theophylline is reasonable in individual patients whose symptoms remain troublesome despite a trial of steroids and optimal doses of inhaled bronchodilators.

Acute Disease↗
PubMed1990

Thallous chloride uptake and DNA profile in parathyroid adenomas.

Thallium isotope scintigraphy is used to localize parathyroid adenomas but the mechanism underlying the technique is poorly understood. While larger adenomas are reliably localized the results are less certain for small tumours. This study explores the relationship between cellular DNA profile and thallium uptake (localization accuracy) in 24 parathyroid adenomas. The DNA profile was assessed using flow cytometry and standard subtraction thallium scintigraphy was performed before surgery. Fifteen of the 24 adenomas demonstrated excessive mitotic activity and 13 of these glands were accurately localized. Of the remaining nine glands, only five were localized accurately (P less than 0.01, chi 2 test including Yates' correction). This difference in thallium uptake could not be accounted for on the basis of gland weight. Thallium localization of parathyroid adenomas is related to mitotic activity. This may explain some of the limitations of this technique.

Adenoma↗
PubMed1990

Value of washings and brushings at fibreoptic bronchoscopy in the diagnosis of lung cancer.

A retrospective study was performed to evaluate the diagnostic yield for lung cancer from histological biopsy specimens and from washings and brushings for cytological examination taken at fibreoptic bronchoscopy. The records of 680 bronchoscopies were analysed. Of 300 patients eventually diagnosed as having a malignant lesion, 188 had had biopsy, washing, and brushing. Of these, 125 had endoscopically visible tumour (group A) and 63 had no abnormal findings or abnormal findings that were not diagnostic of malignancy (group B). In group A biopsy specimens gave a positive result in 76% of cases, washings in 49.6%, and brushings in 52%; biopsy material gave the only positive result in 22.4% of cases, washings in 2.2%, and brushings in 4.8%. In group B biopsy specimens were positive in 36.5%, washings in 38.1%, and brushings in 28.6%; biopsy gave the only positive result in 11.1% of cases, washing in 9.5%, and brushing in 3.2%. Washing had a higher diagnostic yield than brushing in group B. Biopsy and cytological examination of either washings or brushings were found to give over 95% of all positive results in group A, but in group B the combination of biopsy and washing was more often successful (94.3%) than biopsy and brushing (82.8%). It is concluded that for the maximum diagnostic yield in the diagnosis of lung cancer biopsy should be combined with cytology using both washings and brushings.

Bronchoalveolar Lavage Fluid↗
PubMed1989

Hypertension and renal dysfunction in primary hyperparathyroidism: effect of parathyroidectomy.

1. Twenty-four patients with primary hyperparathyroidism were studied before and 18 restudied 6.5 months (mean) after parathyroidectomy, to investigate the pathogenesis of the hypertension which may accompany this condition. Comparison was made with age-matched patients with essential hypertension and with normotensive control subjects. 2. There was a significant inverse relationship between mean arterial pressure and 51Cr-labelled ethylene-diaminetetra-acetate (51Cr-EDTA) clearance in patients with hyperparathyroidism both before and after parathyroidectomy, but not in patients with essential hypertension. 3. Creatinine clearance appeared to overestimate glomerular filtration rate in some patients with hyperparathyroidism, falling significantly after surgery while 51Cr-EDTA clearance was unchanged. This observation may explain the failure of some previous studies to relate hypertension to impairment of renal function. 4. Plasma renin activity, plasma aldosterone and whole-body exchangeable sodium did not differ between normotensive and hypertensive patients with primary hyperparathyroidism and were unchanged after surgery. 5. Parathyroidectomy did not result in any change in blood pressure or in glomerular filtration rate measured by 51Cr-EDTA clearance.

Adult↗
PubMed1988

Cryptogenic bilateral fibrosing pleuritis.

We describe four patients with bilateral pleural effusions progressing to diffuse pleural thickening for which we have been unable to find any evidence of an infective, embolic or occupational aetiology. In order to avoid confusion with diffuse pleural thickening attributable to asbestos-related disease, the term cryptogenic bilateral fibrosing pleuritis is suggested. The patients differed from those with pleural shadowing due to asbestos in that none of them gave a history of asbestos exposure, all were ill, presented with chest pain which was not always pleuritic in character, and had dyspnoea, cough or malaise. They had pleural effusions of variable size, pleural shadowing radiographically and raised sedimentation rates. Computed tomography revealed bilateral extensive pleural thickening in all cases. All four were HLA B44 positive. Histology showed that in all cases the pleura was thickened by fibrous tissue. Both layers were affected and the pleural space was often obliterated. Otherwise the pleural surface was covered by organizing fibrin. Focal collections of lymphocytes were often present when the fibrous tissue abutted on the subpleural fat. No asbestos bodies were seen in any of the cases and in one patient electron microscopic fibre counts showed no excess of asbestos. Pleural decortication was successful in three patients. In one of these, contralateral disease was successfully controlled with corticosteroids, but the fourth patient has not improved on corticosteroids.

Adult↗
PubMed1988

Mycobacterium xenopi infection and aspergilloma.

In 11 patients with pulmonary disease due to Mycobacterium xenopi, definite aspergilloma subsequently developed in five and probable aspergilloma in a further three. Those patients with evidence of Aspergillus infection formed a much higher proportion (73%) than in previous reports of patients with mycobacterial disease. Patients with both Mycobacterium xenopi infection and aspergilloma appear to have a poor prognosis.

Adult↗