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Biomedical subjects

D Chamberlain

Publications and source records attributed to D Chamberlain.

At least 109 records · Page 6Linked to original sources

The effect of prenylamine on the QT interval of the resting electrocardiogram in patients with angina pectoris.

Resting ECGs were recorded in 29 patients with angina pectoris before, during and after treatment with prenylamine 180 mg daily. The QT interval became significantly prolonged after one week of treatment. The prolongation persisted as long as therapy was continued, which was up to 6 months. After withdrawal of treatment the QT interval returned to normal within 2 weeks. In this study no serious problems were encountered by those patients in whom the QT interval was prolonged.

Adult↗

Isoxsuprine infusion to the pregnant rabbit and its effect on fetal lung surfactant.

Rabbit does, pregnant on the 28th day, were infused with isoxsuprine 2.5 mg/kg body weight/h in 50 ml 5% glucose, or with glucose only. The isoxsuprine caused maternal heart rate to increase and blood pressure, mean and diastolic, to decrease. The volume of fetal pulmonary fluid (FPF) and the wet lung weight/body weight ratio were significantly lowered by isoxsuprine. Lecithin/sphingomyelin ratio of FPF in isoxsuprine-infused animals was higher, compared with controls, not infused. Minimal surface tension of FPF, evaluated with pulsating bubble, was significantly lower in treated fetuses. Histologic examination of the fetal lungs after fixation with potassium dichromate and mercuric chloride showed that in isoxsuprine-treated litters FPF contained more granular and sudanophilic material. The results offer further evidence that isoxsuprine causes dehydration of fetal lungs and a release of pulmonary surfactant.

Animals↗

Oncocytic lesions of the larynx.

Eight cases of laryngeal oncocytic lesions treated at Toronto Western Hospital between 1957 and 1977 are reviewed. The typical clinical course was of a benign lesion with prolonged dysphonia. A smaller number with bulkier lesions developed symptoms of airway obstruction. The lesions were supraglottic and cystic. They were excised either endoscopically or via a laryngofissure. The pathologic features support the concept that the lesion represents a metaplasiahyperplasia, and therefore the term 'oncocytic cyst' is preferred to terms which imply a neoplastic process. Three patients with oncocytic cysts had associated squamous dysplasia of the vocal cord. Pathologically this supports the theory of tissue response to chronic irritation, since all three were heavy smokers. Clincially the finding necessitates longterm follow-up with a view to possible squamous cell carcinoma that may arise on the true cords. Follow-up in this series showed no recurrence of symptoms in six of eight cases, two being lost to follow-up.

Adult↗

Isoxsuprine-induced release of pulmonary surfactant in the rabbit fetus.

Rabbit fetuses were injected intramuscularly with 0.5 mg. of isoxsuprine on the twenty-eighth day of gestation. They were killed in utero four hours after the injection, and fetal pulmonary fluid (FPF) was collected through a tracheal catheter. The quantity of FPF and the lung weight/body weight ratio were both significantly less in the isoxsuprine-treated fetuses than in control fetuses. Surface activity, evaluated with pulsating bubble, and the lecithin/sphingomyelin (L/S) ratio were greater in FPF from isoxsuprine-treated animals than in control samples. We concluded that isoxsuprine is able to dehydrate the fetal lung and cause a release of surfactant stored in type II pneumocytes. This latter conclusion was supported by a significant decrease in the number of lamellar inclusions observed in these cells.

Amniotic Fluid↗

Purpura associated with hypergammaglobulinemia, renal tubular acidosis and osteomalacia.

Two patients with hyperglobulinemia associated with purpura were studied. One had features of Sjögren's syndrome, while the other appeared to have a primary condition -- "chronic benign purpura". Both patients also had renal tubular acidosis, osteomalacia and renal calculi, with disturbed calcium metabolism and acid-base balance. Autoantibodies were detected in the serum of both patients, and mononuclear cell infiltrates were noted in skin and kidney biopsies from both.

Acid-Base Equilibrium↗

Pulmonary hypoplasia in babies with severe rhesus isoimmunisation: a quantitative study.

Analysis of lung weights of 96 infants dying with rhesus isoimmunisation has shown that the lung is considerably retarded in its growth. Detailed analysis of the lungs of six babies after pulmonary artery injection showed in all a reduction in airway number and thus acinar and artery number, suggesting arrest in growth before the 16th week of gestation. The alveoli were also of either abnormal number, size or maturity, suggesting a continuing effect in later foetal life. Total lung volume varied from the normal value in one case to one-quarter normal in the smallest lung.

Angiography↗

Myocardial and skeletal muscle concentrations of digoxin in patients on long-term therapy.

The digoxin content was measured in samples of left ventricular papillary muscle, skeletal muscle, and plasma obtained during mitral valve replacement from eight patients on maintenance treatment with the drug. The content in papillary muscle ranged from 15.5 to 132 ng/g (mean 77.7) and in skeletal muscle from 7.5 to 23 ng/g (mean 11.3). The ratio of myocardial digoxin concentration to plasma concentration varied between patients from 39:1 to 155:1. No simple relationship exists between plasma levels of digoxin and its concentration in the heart muscle, but total myocardial concentration may not accurately reflect therapeutic activity.

Adult↗

Difficult asthma: consider all of the possibilities.

Asthma is a common respiratory disease that can often be managed successfully. However, there are patients that do not respond to the maximum doses of standard therapy and subsequently have a reduced quality of life. Many factors can contribute to a failure to respond to treatment, and a comprehensive approach is important when assessing and evaluating these patients. This report describes a patient referred for 'difficult to control asthma' who had multiple emergency department visits and hospitalizations. In addition to a history of wheezing, spirometry showed impaired flow and vital capacity was reduced. Further investigation showed a normal total lung capacity, and a computed tomography scan revealed main bronchus blockage by a tumour, which was confirmed by bronchoscopy. This led to a surgical resection of a mucoepidermoid carcinoma. This case highlights the need to consider all possibilities during the evaluation of patients with difficult asthma.

Adult↗

Treatment for amblyopia: results using occlusive contact lens.

PURPOSE: Amblyopia treatment occasionally is complicated by patch intolerance, resulting in a poor outcome. Therefore, a prospective study was designed to examine the efficacy and safety of using occlusive contact lenses in the treatment of amblyopia. METHODS: Twenty-five patients, aged 2.5 to 9.5 years, who were using an opaque hydrogel contact lens for the treatment of amblyopia, were followed prospectively. RESULTS: Overall, 92% of patients improved at least one line of visual acuity. Eight patients improved > or = 2 octaves and 12 other patients improved > or = 1 octave. In three patients, the change in visual acuity was < 1 octave. Complications were seen in nine patients: contact lens irritation in five; poor contact fit in three; and peeking around the lens in one. The recurrence rate was high. In 11 of 25 patients, amblyopia rapidly returned to a reduced level when the contact lens was discontinued. CONCLUSIONS: Occlusive contact lenses can be used in treating amblyopia in children. This treatment is ideal in patients who were patch-intolerant and failed with conventional treatment. Patients should have close follow up, however, to monitor any anterior segment complications from contact lens use and to identify the patients in whom amblyopia recurs.

Amblyopia↗

Acute lung injury in lung allografts.

BACKGROUND: Acute alveolar injury is a pathologic description of a nonspecific response of the lung to an acute injury. It has been our experience that acute alveolar injury may be seen in transbronchial biopsy and open lung biopsy specimens from patients who have successfully undergone lung transplantation. Because no studies of the clinical significance of acute alveolar injury in lung transplant recipients are available in the literature, we reviewed the impact of this pathologic finding in patients who underwent transplantation in the Toronto Lung Transplant Program. METHODS: From November 1983 through December 1992, we retrospectively reviewed all transbronchial biopsies and open lung biopsies performed in lung transplant recipients. RESULTS: Of the 137 transplantations performed (53 single and 84 double) acute alveolar injury was observed in 21 single (34 of 173 transbronchial biopsy and 3 of 11 open lung biopsy) lung biopsy) and 22 double (38 of 415 transbronchial biopsy and 3 of 11 open lung biopsy) lung transplantations. We sought to explain this finding on the basis of the concurrent clinical scenario. Acute alveolar injury occurred most commonly in association with infection (52%) followed by postoperative period (19%) and acute (16%) rejection. Acute alveolar injury occurred as an isolated finding in 7% of patients. It occurred within the first 4 months after transplantation in 80% of cases. In 10 of 21 single lung transplantations and 12 of 22 double lung transplantations, acute alveolar injury was seen at least twice. However, no difference was found in mortality between such patients (6 of 10 single and 6 of 12 double lung transplantations) and patients with only one episode of acute alveolar injury. CONCLUSION: Acute alveolar injury is a relatively common finding in histologic specimens from patients with lung transplantation and is most commonly associated with infection.

Biopsy↗

Causes of death in lung transplant recipients.

Between November 1983 and September 1992, The Toronto Lung Transplant Program performed 131 lung transplantations in 122 recipients; 53 single lung transplantations and 78 double lung transplantations. Forty-five patients died, 25 (47%) in the single lung transplantation and 20 (25%) in the double lung transplantation groups. We retrospectively reviewed the hospital charts of all deceased recipients and the postmortem reports of the 35 patients (20 single lung transplantations and 15 double lung transplantations) who had autopsies. Preoperative single lung transplantation diagnoses included pulmonary fibrosis, (n = 17) obstructive disease (n = 6) and vascular disease (n = 2). Preoperative diagnosis of double lung transplantation included pulmonary fibrosis (n = 2), obstructive disease (n = 6), septic lung disease (n = 9), and vascular disease (n = 3). The most common cause of death in single lung transplantation was infection. Five patients died of bronchiolitis obliterans, and five more had bronchiolitis obliterans lesions present at autopsy that were not a direct cause of death. Diagnosis of primary disease was made in 23 of 25 single lung transplantations antemortem and 2 of 25 at autopsy. Autopsy diagnoses were disseminated Aspergillus and cytomegalovirus infection. In double lung transplantations, infection was also the primary cause of death; in three other patients, airway dehiscence preceded infection. Bronchiolitis obliterans was the second most common cause of death and was also present in four patients dying of infection. All double lung transplantation diagnoses were made antemortem. We concluded that infection and then bronchiolitis obliterans are the primary causes of death after lung transplantation. Although infection is a major cause both early and late after transplantation, bronchiolitis obliterans is an important factor in transplantation only late after the operation.

Adolescent↗