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Biomedical subjects

A A Conlan

Publications and source records attributed to A A Conlan.

At least 19 recordsLinked to original sources
PubMed1996

Biotransformation of aflatoxin B1 in human lung.

In addition to being a potent hepatocarcinogen, aflatoxin B1 (AFB1) is a pulmonary carcinogen in experimental animals, and epidemiological studies have shown an association between AFB1 exposure and lung cancer in humans. This study investigated AFB1 bioactivation and detoxification in human lung tissue obtained from patients undergoing clinically indicated lobectomy. [3H]AFB1 was bioactivated to a DNA binding metabolite by human whole lung cytosols in a time-, protein concentration-, and AFB1 concentration-dependent manner. Cytosolic activation of [3H]AFB1 correlated with lipoxygenase (LOX) activity and was inhibited by the LOX inhibitor nordihydroguaiaretic acid (NDGA; 100 microM), indicating that LOXs were largely responsible for the observed cytosolic activation of AFB1. In whole lung microsomes, low levels of indomethacin inhibitable prostaglandin H synthase (PHS)-mediated [3H]AFB1-DNA binding and cytochrome P-450 (P450)-mediated [3H]AFB1-DNA binding were observed. Cytosolic glutathione S-transferase (GST)-catalyzed detoxification of AFB1-8,9-epoxide, produced by rabbit liver microsomes, was minimal at 1 and 10 microM [3H]AFB1. With 100 microM [3H]AFB1, [3H]AFB1-8,9-epoxide conjugation with reduced glutathione was 0.34 +/- 0.26 pmol/mg/h (n = 10). In intact, isolated human lung cells, [3H]AFB1 binding to cellular DNA was higher in cell fractions enriched in macrophages than in either type II cell-enriched fractions or fractions containing unseparated cell types. Indomethacin produced a 63-100% decrease in [3H]AFB1-DNA binding in macrophages from five of seven patients, while NDGA inhibited [3H]AFB1-DNA adduct formation by 19, 40 and 56% in macrophages from three of seven patients. In alveolar type II cells, NDGA decreased [3H]AFB1-DNA binding by 30-100% in cells from three patients and indomethacin had little effect. SKF525A, an isozyme non-selective P450 inhibitor, enhanced [3H]AFB1 binding to cellular DNA in unseparated cells, macrophages, and type II cells, suggesting that P450-mediated bioactivation of AFB1 is not a major pathway by which AFB1-8,9-epoxide is formed in human lung cells. Overall, these studies suggest that P450 has a minor role in the bioactivation of AFB1 in human lung. Rather, LOXs and PHS appear to be important bioactivation enzymes. Co-oxidative bioactivation of AFB1, in combination with the low conjugating activity displayed by human lung cytosolic GSTs, likely contributes to human pulmonary susceptibility to AFB1.

Aflatoxin B1↗
PubMed1996

Mechanisms of relief of exertional breathlessness following unilateral bullectomy and lung volume reduction surgery in emphysema.

STUDY OBJECTIVE: To explore mechanisms of relief of exertional breathlessness following surgery to reduce thoracic gas volume in patients with emphysema. MATERIALS AND METHODS: We studied 8 patients with emphysema (FEV1 = 39 +/- 3% predicted; residual volume [RV] = 234 +/- 12% predicted; mean +/- SEM) who were severely breathless despite optimal pharmacotherapy and who underwent unilateral bullectomy for giant bullae (greater than one third hemithorax); 4 of these also had ipsilateral lung reduction (pneumectomy). Pulmonary function and cycle exercise performance (n = 6) were evaluated before and 13 +/- 3 weeks after surgery. Chronic breathlessness was measured with the Baseline Dyspnea Index and the Medical Research Council dyspnea scale. Exertional breathlessness was measured using Borg ratings at a standardized work rate (BorgSTD). RESULTS: FEV1, FVC, and maximal inspiratory pressures increased postsurgery by 29 +/- 7% (p < 0.05), 24 +/- 10% (p = 0.06), and 39 +/- 12% (p < 0.01), respectively. Plethysmographic total lung capacity, RV, and functional residual capacity fell by 14 +/- 2%, 30 +/- 4%, and 18 +/- 3%, respectively (p < 0.001). All measures of chronic breathlessness improved significantly (p < 0.05). During exercise at a standardized work rate, BorgSTD fell 45% (p < 0.05), end-expiratory lung volume (EELV) fell 22% (p < 0.01), and breathing frequency (F) fell 25% (p = 0.08). By multiple stepwise regression analysis, 99% (p = 0.007) of the variance in symptom relief (delta BorgSTD) was explained by the combination of decreased ratio of the end-expiratory lung volume to total lung capacity, decreased F, and diminished mechanical constraints on tidal volume (tidal volume to vital capacity ratio). CONCLUSION: Reduced exertional breathlessness at a given workload after volume reduction surgery was attributed to a combination of reduced thoracic hyperinflation, reduced F, and reduced mechanical constraints on lung volume expansion.

Dyspnea↗
PubMed1996

Left hilar mass with obstruction of the main bronchus due to localized pseudoaneurysm of the thoracic aorta.

The left hilum is an anatomically complex region. It is poorly imaged on conventional chest roentgenography and even on tomography. A wide range of diagnoses must be considered upon discovery of a hilar mass. In this report, the authors discuss their experience with a potentially hazardous hilar mass found in a 61-year-old man with a 40 pack-year smoking history. The mass, which was identified as an aortic pseudoaneurysm, caused near-total obstruction of the left main bronchus. The aneurysm was successfully repaired and patency of the bronchus restored. Radiographic features that suggest an aortic aneurysm as a cause of a hilar mass include posterior location and lack of associated mediastinal or contralateral hilar adenopathy. Computer tomography with contrast will readily define a vascular hilar mass. If cancer or lymphoma are suspected as the cause of a hilar mass, mediastinal lymph-node imaging, and aspiration or biopsy are indicated.

Aneurysm, False↗
PubMed1995

Elective pneumonectomy for benign lung disease: modern-day mortality and morbidity.

This retrospective study of elective pneumonectomy for complicated inflammatory lung disease was done to define modern-day mortality and morbidity. One hundred twenty-four patients received elective pneumonectomy. Patient ages ranged from 6 months to 71 years. Past, recurrent, or new pulmonary tuberculosis was present in 107 patients (86.3%). Clinical presentation involved recurrent infections or severe suppurative sequelae (abscess, empyema). Forty-seven patients had chronic hemoptysis and 25 patients had past or recent massive hemoptysis (> 600 ml of hemoptysis fluid within 24 hours). Nutritional deficiencies were common. One hundred six patients (85.5%) had end-stage destroyed lungs. Evaluative bronchoscopy showed inflammatory endobronchial changes in 106 patients (85.5%), bronchial strictures in 4, and indolent endobronchial tumor in 2. Lung separation was by double-lumen tube in 96 patients, single lung-single tube in 6, bronchus blocker in 6, and prone posture in 9. Extrapleural pneumonectomy was done in 83 patients (66.9%). Fifty-seven of these procedures were left sided and 26 were right sided. Standard transpleural pneumonectomy was done in 41 patients (33.1%): 30 left sided and 11 right sided. Nine pneumonectomies were conducted with the patient in the prone position. Four patients had completion pneumonectomy. Hospital mortality was three deaths (2.4%). Morbidity included postpneumonectomy empyema in 19 patients (15.3%). Seven postoperative bronchopleural fistulas occurred. Empyema in most patients was managed by open pleural drainage (thoracostoma) and later space closure. Pneumonectomy proved effective therapy with low mortality but postpneumonectomy empyema posed serious morbidity.

Adolescent↗
PubMed1994

Unusual site of spontaneous first-rib fracture: case report.

Spontaneous fractures of the first rib are uncommon and are usually thought to be associated with a malignant process. However, fatigue fractures of the first rib are being encountered increasingly in association with various physical activities. Typically, the fractures occur at the subclavian groove, but in the 48-year-old woman described in this report the fracture was unexpectedly situated in the posterior portion of the rib and was the result of snow shovelling, which was a new activity for the patient.

Female↗
PubMed1990

Surgical management of the redundant transposed colon.

Redundancy of the transposed thoracic colon is not uncommon. Rarely, however, when accompanied by severe symptoms, it may necessitate surgical correction. We describe herein a surgical technique that allows the stretching and straightening of the redundant transposed organ.

Anastomosis, Surgical↗
PubMed1987

Pulmonary aspergilloma--indications for surgical intervention. An analysis of 22 cases.

Surgical resection of aspergillomas has generally been associated with excess mortality and morbidity; 22 patients who had a resection of complicated mycetomas were studied retrospectively. Indications for surgery were serious haemoptysis (14), massive haemoptysis (6), and recurrent infection (2). Extrapleural pneumonectomy was required in 9 patients and extrapleural lobectomy in 12; thoracoplasty alone was done in 1 patient. There was 1 hospital death (4.5%); 4 patients developed postoperative empyemas (18%), 2 with associated bronchopleural fistulas. Two further patients (9%) had stable postresectional spaces. Surgery for complicated aspergilloma was associated with significant postoperative morbidity.

Adult↗
PubMed1986

Avoidance of jejunostomy. A reliable method of naso-enteral tube placement after oesophageal surgery.

Nutritional maintenance after oesophageal surgery and during treatment of oesophageal disease is given high priority. A method of naso-enteral feeding tube placement suitable for these patient groups was evolved and studied prospectively. A standard nasogastric tube is used as a conduit for a guide-wire over which a soft, small-bone naso-enteral tube is threaded into position. Thirty patients underwent placement of such tubes postoperatively or during treatment of oesophageal disease. Placement and feeding was successful in all. Six patients developed controllable diarrhoea.

Enteral Nutrition↗
PubMed1986

Resectable pulmonary nephroblastoma metastases presenting as chest wall lesions on radiography. A report of 2 cases.

Two children with pulmonary metastases from nephroblastomas showed the radiological features of chest wall tumour involvement. Diagnostic surgical exploration subsequently revealed pedunculated and fully resectable peripheral lung metastases. The mechanism by which these pedunculated lesions mimicked the classic 'D sign' of an extrapulmonary (pleural or chest wall) tumour is explained.

Child, Preschool↗
PubMed1986

Pulmonary resection in the prone position for suppurative lung disease in children.

Lung resection for suppurative inflammatory disease is hazardous in children whose small airway diameter precludes the use of standard methods of bronchial separation. A prospective evaluation of the prone position for thoracotomy in 17 children referred for operation with severe inflammatory disease was done. Bronchography showed whole lung bronchiectasis eight, destroyed lung in three, and lobar bronchiectasis five. Pulmonary resections performed with the child prone included left pneumonectomy (nine), right pneumonectomy (four), lingulectomy with lower lobectomy (two), and other lobectomy (two). No endobronchial or intrapleural spillage occurred. One child required reexploration for bleeding and one child developed a postoperative empyema that ultimately caused death. The remaining 16 children were discharged within 8 days of operation, and follow-up of 1 to 18 months records favorable progress.

Bronchiectasis↗
PubMed1985

The microflora of chronic pleural empyema. An analysis of 89 patients.

Bacteriological cultures from 89 patients with chronic pleural empyema were studied. Seventy-nine patients had positive and 10 negative culture results. Forty-eight patients had a single isolate--pyogenic cocci in 32 and Gram-negative enteric bacilli in 16--and multiple organisms were grown in 31 patients. Anaerobic organisms were recovered in 6,2%. Our negative culture rate of 11,2% may reflect failure to recover anaerobes, but could represent sterilization of the empyema by prior use of antibiotics. The results of antibiotic sensitivity tests and the pathogenicity of the organisms recovered suggest that the choice of antibiotic combinations for chronic pleural empyema requires careful consideration.

Adolescent↗
PubMed1985

Bronchiectasis in urban black children.

From July 1979 to July 1982, 29 cases of childhood bronchiectasis were encountered at Leratong Hospital. They were retrospectively divided into two groups: 16 patients underwent surgical intervention and the other 13 patients received medical treatment only. Symptoms and signs were reviewed and findings on bronchography were studied. The left lower lobe was the most common site of involvement, and the lingular segment was invariably also affected by bronchiectatic changes. Ten of the surgical patients (63%) underwent pneumonectomy. In 75% of the surgical group there was an excellent or good result after surgery, while a good result was achieved in 40% of those receiving medical treatment only. We have reviewed other large series to compare surgical and medical management, and discuss factors that may influence the outcome of surgical treatment.

Adolescent↗
PubMed1985

Normovolaemic haemodilution using dextran 70 in thoracic surgery.

Normovolaemic haemodilution was undertaken in 10 patients requiring elective thoracic surgery. The resultant blood loss, cell loss, use of donor blood and acid-base changes were compared with those in 10 patients undergoing similar procedures who were anaesthetized in the standard manner. Normovolaemic haemodilution reduces the use of donor blood and provides more satisfactory acid-base status than that in controls. The known antithrombotic effect of dextran 70 (Macrodex; Saphar) did not affect the crude clotting time. The technique is a feasible alternative to use of donor blood, especially when difficulties in supply exist or there is a high risk of disease transmission.

Adolescent↗
PubMed1985

Pleural sinography in the management of thoracic empyema. A study of 52 cases.

Pleural sinography is indicated in the management of empyema thoracis. The factors influencing the successful completion and interpretation of this procedure are discussed. A retrospective study of 86 sinograms from 52 patients with pleural empyema was undertaken to identify how the information obtained influenced management decisions and affected therapy. Pleural sinography is a valuable study within the limitations of correct performance and interpretation.

Adolescent↗