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Biomedical subjects

B R Wilcox

Publications and source records attributed to B R Wilcox.

At least 19 recordsLinked to original sources
PubMed1992

Isolated lung transplantation for end-stage lung disease: a viable therapy.

Since January 1990, we have performed 29 isolated lung transplantations in 28 patients with end-stage lung disease (12 single, 16 bilateral). Recipient diagnoses were: cystic fibrosis (11), chronic obstructive pulmonary disease (6), pulmonary fibrosis (6), eosinophilic granulomatosis (1), postinfectious lung disease (1), adult respiratory distress syndrome (1), and primary pulmonary hypertension (2). There have been four deaths, two in patients with pulmonary fibrosis and two in patients with primary pulmonary hypertension. Four patients have undergone transplantation while on ventilatory support for respiratory failure (2 with cystic fibrosis, 1 having redo lung transplantation with cystic fibrosis, and 1 with adult respiratory distress syndrome); all of these have survived. Six patients required cardiopulmonary bypass, which was associated with increased transfusion requirement. All patients 2 months after discharge have returned to an active life-style, except for 2 patients who currently await retransplantation. Preoperative pulmonary rehabilitation has resulted in significant improvement in exercise performance in all patients. Immunosuppression consists of cyclosporine, azathioprine, and antilymphoblast globulin (University of Minnesota), withholding systemic steroids in the early postoperative period. We have employed bronchial omentopexy in all but four transplants; there has been one partial bronchial dehiscence, two instances of bronchomalacia requiring internal stenting, and one airway stenosis. Cytomegalovirus disease has been seen frequently (15 cases), but has responded well to treatment with ganciclovir. Other complication shave included one drug-related prolonged postoperative ventilation, thrombosis of a left lung after bilateral lung transplantation requiring retransplantation, five episodes of unilateral phrenic nerve palsy after bilateral lung transplantation (4 resolved), and the requirement of massive transfusion (greater than 10 units) in 5 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Single lung transplantation for eosinophilic granulomatosis.

A 26-year-old woman with end-stage lung disease due to eosinophilic granulomatosis had single right lung transplantation with an excellent function result that persists beyond 9 months of follow-up. Single lung transplantation offers excellent palliation to selected patients with end-stage lung disease.

Adult↗
PubMed1992

The surgical anatomy of ventricular septal defect.

There is still no consensus as to how best to categorize and describe interventricular communications. In a series of three reviews, a system will be described showing how the anatomical criteria chosen for categorization will also serve as a guide for surgeons as to the location of the axis responsible for atrioventricular conduction tissue. In this first review, the defects described are not complicated by overriding of arterial or atrioventricular valves and are present in hearts that have basically normal segmental connections, or have some discordant connections (complete transposition or congenitally corrected transposition). The rims of the defect categorize the boundaries to which a surgeon may place a patch. Variations in these rims produce three classes of defect: perimembranous; muscular; and doubly committed and juxtaarterial (subarterial). The second part of the classification recognizes the further variation existing with respect to the component of the morphologically right ventricle into which the defect predominantly empties. Deficient atrioventricular septation can also lead to interventricular shunting in isolation, but the morphology is then quite different from hearts with simple deficiencies of the ventricular septum. We emphasize the abnormal location of the atrioventricular node in hearts with atrioventricular, as opposed to ventricular, septal defects.

Endocardial Cushion Defects↗
PubMed1991

Enhanced pulmonary function using dimethylthiourea for twelve-hour lung preservation.

Current preservation techniques for lung transplantation limit ischemic time to 6 hours. The purpose of this study was to evaluate the ability of dimethylthiourea, a low molecular weight free radical scavenger, to prolong this interval. An in vivo canine transplantation model was used to assess lung function. At harvest and after circulatory arrest, the donor lung was flushed with modified Euro-Collins solution (50 mL/kg). In a blinded fashion, dimethylthiourea (5 g) or saline solution was added to the flush solution at harvest and also infused (20 g over 2 hours) at reimplantation. Harvested lungs were stored for 12 hours at 4 degrees C. Allotransplantation was performed in recipient dogs ventilated with 40% O2. After 1 hour, the contralateral pulmonary artery was ligated, forcing the dog to be dependent on the transplanted lung. Twelve dogs were studied, with 6 randomly assigned to each treatment group in a blinded fashion. Measurements were recorded for 8 hours, keeping the inspired oxygen fraction constant at 0.40. All dimethylthiourea-treated dogs survived the observation period, whereas one third of the dogs that received saline solution died. Dimethylthiourea-treated dogs had significantly greater arterial oxygen tension and significantly less pulmonary vascular resistance compared with control animals. These results suggest that treatment of the lung with a free radical scavenger (dimethylthiourea) improves pulmonary function after reimplantation in a canine model after 12-hour hypothermic storage.

Animals↗
PubMed1991

A strategy to increase the donor pool: use of cadaver lungs for transplantation.

A shortage of suitable donors is a serious obstacle to the widespread application of isolated lung transplantation for end-stage lung disease. We hypothesized that lung tissue likely remains viable for a sufficient period of time to allow for safe postmortem retrieval of lungs for transplantation. Studies were conducted in a nonsurvival model of canine lung allotransplantation. Donor animals were sacrificed, and subsequent lung harvest was delayed for 1 hour, 2 hours, or 4 hours. Pulmonary retrieval was then performed in a standard fashion, flushing the lung block with modified Euro-Collins solution. Lungs were then stored for 4 hours before single allotransplantation. Recipient animals were maintained anesthetized, and followed up for 8 hours. By occlusion of the pulmonary artery and bronchus to the native lung, recipient animals were forced to survive solely on the transplanted lung, with a constant inspired oxygen fraction of 0.40. All 5 recipient animals of 1-hour cadaver lungs survived the 8-hour observation period with excellent hemodynamics and gas exchange. Two of 5 recipients of 2-hour cadaver lungs survived the observation period, whereas a third animal survived for 5 hours with excellent gas exchange. One of 4 animals transplanted with a 4-hour cadaver lung survived the observation period. Retrieval of lungs from cadavers whose hearts are not beating may prove to be a safe and effective method to increase the pulmonary donor pool.

Animals↗
PubMed1990

Unusual opening of coronary sinus in atrioventricular septal defects.

The coronary sinus is an important landmark for the position of the atrial component of the atrioventricular conduction axis and, thus, assumes special relevance to the surgeon in the operating room. We describe here 2 patients with atrioventricular septal defect characterized by an unusual termination of the coronary sinus within the left atrium. We discuss the potential importance of this finding to the disposition and surgical avoidance of the conduction tissues.

Abnormalities, Multiple↗
PubMed1990

Oxygen free radical scavengers decrease reperfusion injury in lung transplantation.

An in vivo canine model was used to assess the ability of an oxygen free radical scavenger to decrease reperfusion injury in lung transplantation. In 12 dogs, the left lungs were transplanted after they had been preserved for 24 hours at 4 degrees C after pulmonary artery flushing with modified Eurocollins solution. In 6 dogs, dimethylthiourea, a potent oxygen free radical scavenger, was added to the flush solution and was also given to the recipients just before reperfusion. In all animals, the contralateral pulmonary artery and bronchus were ligated and lung function was assessed for 12 hours or until death. Three dogs died prematurely in the control group, whereas only 1 dog died prematurely in the dimethylthiourea group. This resulted in a statistically significant difference in the average length of survival (p less than 0.05). Pulmonary artery and right atrial pressures were significantly lower in the dimethylthiourea group during the first 6 hours (p less than 0.05). Treatment with dimethylthiourea resulted in a significantly higher arterial oxygen tension at 4 hours, and intrapulmonary shunt tended to be lower. Thus, it would appear that dimethylthiourea has a protective effect on lungs preserved for 24 hours before transplantation in dogs.

Animals↗
PubMed1989

Improved lung preservation using a dimethylthiourea flush.

The purpose of this study was to evaluate the ability of dimethylthiourea (DMTU), a low molecular weight hydroxyl free radical scavenger, to improve preservation of the lung for transplantation. Following preservation, 15 isolated canine left lower lobes were reperfused for 90 min with autologous blood. Five group I lobes served as controls and were not subjected to ischemia prior to reperfusion. Five group II lobes were flushed and submerged in a cold Euro-Collins solution and stored for 4 hr at 4 degrees C prior to reperfusion. Group III lobes were flushed with a 20 mM DMTU-enhanced Euro-Collins solution, stored for 4 hr, and then reperfused. The isogravimetric method was utilized to determine the capillary permeability coefficient (Kfc) for the reperfused lobes. The Kfc values were 0.10 +/- 0.01, 0.17 +/- 0.01, and 0.10 +/- 0.008 ml/min/mm Hg/100 g lung for groups I, II, and III, respectively (P less than 0.01 II vs I, III). Extravascular lung water values in the reperfused lobe were 4.44 +/- 0.45, 6.57 +/- 0.38, and 5.23 +/- 0.22 ml/g blood free dry lung weight for groups I, II, and III (P less than .05, II vs. I, III). Lung lipid peroxidation, measured as thiobarbituric acid-reactive material, was higher in group II, 146 +/- 6 nmole/g, than in either group I, 90 +/- 5 nmole/g, or group III, 91 +/- 4 nmole/g (P less than 0.01). The results indicate that the addition of DMTU improves hypothermic lung preservation by reducing lipid peroxidation and edema formation upon reperfusion.

Animals↗
PubMed1979

The effects of early pneumonectomy on the remaining pulmonary parenchyma.

To determine the age-related response of the remaining pulmonary parenchyma to lung resection, a matched set of 24 purebred beagle dogs underwent pneumonectomy at 6 to 10 weeks of age (group I) or at 1 year of age (group II). Eight unoperated adult beagles served as controls (group III). One year after pneumonectomy, pulmonary hemodynamics in group I were the same as those in older animals shortly after pneumonectomy and in normal control animals. Functional residual capacity, total lung capacity, single breath diffusing capacity for carbon monoxide, and static lung compliance were measured in all three groups while anesthetized and intubated. Lung volumes and diffusion capacity for carbon monoxide in group I did not differ significantly from those of control animals. Group I animals did have a lower lung compliance than the control group, but significantly greater than the group II adult pneumonectomy dogs. The adult pneumonectomy dogs (group II) had significantly lower values for lung volumes, diffusion capacity, and compliance when compared to the control group. Arterial blood gases were not significantly different among the groups. It is concluded that beagles undergoing early pneumonectomy have an increase of alveoli beyond the normal complement in the remaining lung with concomitant remodeling of the pulmonary capillary bed resulting in normal lung volumes, diffusing capacity, and gas exchange.

Age Factors↗
PubMed1977

The assessment of operability of esophageal carcinoma.

The extremely poor outlook for patients with esophageal cancer necessitates careful definition of the extent of disease prior to the selection of treatment. Evaluation of regional lymph node involvement may avoid excessive morbidity and identify favorable candidates for aggressive excisional therapy. The role of combined mediastinoscopy and celiotomy in assessing the operability of epidermoid carcinoma of the thoracic esophagus was examined in 30 consecutive candidates for esophageal resection at the North Carolina Memorial Hospital. The prognostic value of combined mediastinoscopy and celiotomy in assessing the operability of epidermoid value in assessing mediastinal extension of carcinoma of the upper thoracic and midthoracic esophagus.

Abdominal Neoplasms↗
PubMed1977

The role of transbronchial lung biopsy in diffuse pulmonary disease.

Forty consecutive patients underwent flexible fiberoptic transbronchial lung biopsy for diagnosis of diffuse nodular or infiltrative lung disease. Biplane fluoroscopic examination with image intensification greatly facilitated accurate placement of the biopsy forceps near the pleura; Specimens of lung parenchyma were obtained for culture and histological study in every case. A pathological diagnosis was correctly established in 34 of 40 patients. Transbronchial biopsy was helpful in the clinical management of an additional 4 patients. Biopsy results were not accurate in 2 patients. No significant morbidity was associated with the procedure. Fiberoptic transbronchial lung biopsy is a safe and useful adjunct to the diagnosis of parenchymal lung disease.

Adolescent↗