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Biomedical subjects

J D Cooper

Publications and source records attributed to J D Cooper.

At least 217 records · Page 12Linked to original sources
PubMed1990

Direct revascularization of bronchial arteries for lung transplantation: an anatomical study.

Direct revascularization of the bronchial arteries for both single-lung and double-lung transplantation would improve airway healing and reduce airway complications after transplantation. We studied the anatomical pattern of bronchial arteries in 30 autopsy cases. In 28 of 30 cases (93.3%), at least one left bronchial artery arose directly from the anterior wall of the descending thoracic aorta. In 25 of the 30 cases (83.3%), at least one right bronchial artery was related to the first right intercostal artery. Injection studies showed that this right intercostobronchial artery supplies the proximal left main bronchus and carina as well as the right bronchus. We developed a technique for extracting the lungs along with the right intercostobronchial artery and a patch of aorta at its origin and applied it to 19 of the dissections. In 17 of the 19 cases studied (89.4%), the right intercostobronchial artery pedicle obtained had a length varying from 6.5 to 8.5 cm, sufficient for attachment of its origin to the ascending aorta of the recipient after double-lung transplantation. The right intercostobronchial artery pedicle provides the possibility for direct bronchial revascularization in right single-lung, double-lung, and lung-heart transplantation. A similar technique, utilizing the left bronchial artery, can be used to revascularize a left lung transplant.

Aorta, Thoracic↗
PubMed1990

Afferent and efferent connections of the laterodorsal tegmental nucleus in the rat.

The connections of the laterodorsal tegmental nucleus (LDTg) have been investigated using anterograde and retrograde lectin tracers with immunocytochemical detection. Inputs to LDTg were found from frontal cortex, diagonal band, preoptic areas, lateral hypothalamus, lateral mamillary nucleus, lateral habenula; the interpeduncular nucleus, ventral tegmental area, substantia nigra and retrorubral fields; the medial terminal nucleus, interstitial nucleus, supraoculomotor central grey, medial pretectum, nucleus of the posterior commissure, paramedian pontine reticular formation, paraabducens and paratrochlear region; the parabrachial nuclei and nucleus of the tractus solitarius. Terminal labelling from PHA-L injections of LDTg was found in infralimbic, cingulate and hippocampal cortex, lateral septum, septofimbrial and triangular nuclei, horizontal limb of diagonal band and preoptic areas; in the anterior, mediodorsal, reuniens, centrolateral, parafascicular, paraventricular and laterodorsal thalamic nuclei, rostral reticular thalamic nucleus, and zona incerta; the lateral habenula and the lateral hypothalamus. A number of brainstem structures apparently associated with visual functions were also innervated, mainly the superior colliculus, medial pretectum, medial terminal nucleus, paramedian pontine reticular formation, inferior olive, supraoculomotor, paraabducens and supragenual regions, prepositus hypoglossi and nucleus of the posterior commissure. Also innervated were substantia nigra compacta, ventral tegmental area, interfascicular nucleus, interpeduncular nucleus, dorsal and medial raphe, pedunculopontine tegmental region, parabrachial nuclei, and nucleus of the tractus solitarius. These findings suggest the LDTg to be a highly differentiated part of the ascending "reticular activating" system, concerned not only with specific cortical and thalamic regions, especially those associated with the limbic system, but also with the basal ganglia, and visual (particularly oculomotor) mechanisms. Additional links with the habenula-interpeduncular system are discussed in this context.

Afferent Pathways↗
PubMed1990

The evolution of techniques and indications for lung transplantation.

The techniques and indications for lung transplantation have evolved significantly in the past 6 years. We initially restricted single-lung transplantation to patients with pulmonary fibrosis and developed the double-lung transplantation procedure for patients with emphysema or cystic fibrosis. However, with the double-lung procedure, a 25% mortality rate resulted from ischemic complications at the tracheal anastomosis. The technique was altered to incorporate bilateral bronchial anastomosis, with a resulting reduction in airway complications. The double-lung transplantation procedure continued to have significant drawbacks, including intraoperative and postoperative hemorrhage, and cardiac complications due to prolonged cardiopulmonary bypass, ischemic cardiac arrest, and extensive manipulation of the heart. These problems recently have been addressed with a much simplified procedure incorporating a bilateral transverse thoracosternotomy, replacement of the right lung without cardiopulmonary bypass, and replacement of the left lung with or without a short period of partial bypass. This procedure has been successfully used for emphysema and for cystic fibrosis. The technique of single-lung transplantation also has been simplified and indications have been expanded to include selected patients with emphysema and with primary pulmonary hypertension. With single-lung transplantation, each of the lungs from a donor has been successfully used for a separate recipient on several occasions, improving the supply of available donor organs.

Animals↗
PubMed1990

Radiologic correlation with early physiologic function of the transplanted canine lung.

There is no single reliable method for assessment of the transplanted lung. Multiple modes of assessment are therefore used. In a canine model designed to assess lung preservation, the reliability of information gained from chest radiographs performed in the early post-transplant period was examined. The function of 20 left lung allografts, stored for 12 hours after pulmonary artery flush preservation was studied. Radiographs graded according to disease severity were compared with physiologic function of the transplanted lung assessed immediately and at three days post-transplantation. This protocol enables study of acute preservation-related lung injury and the delayed manifestations of ischemic and reperfusion injury after a three day period of recovery, while avoiding confounding rejection and infectious episodes. The chest radiograph did not reliably reflect function of the flush-preserved transplanted lung. Thus, relying only on this modality may lead to erroneous conclusions. In this study, the progression of radiographic changes associated with the "reimplantation response" differed from previous descriptions, possibly reflecting differences in operative technique or improved lung preservation.

Animals↗
PubMed1990

Cardiopulmonary exercise testing after single and double lung transplantation.

The cardiopulmonary response to exercise was investigated in six single and six double lung transplant recipients using a three-minute incremental work rate protocol on a cycle ergometer. Maximum VO2 averaged 44.2 +/- 9.2 percent and 48.5 +/- 5.0 percent of predicted maximal VO2 in the single and double lung transplant groups, respectively. No evidence of ventilatory limitation to exercise was found in either group. Circulatory factors that may have limited exercise capacity included anemia and submaximal heart rates. There was a strong correlation between VO2/kg at venous blood lactate level of 2.2 mEq/L and vital capacity/body surface area in the single, but not in the double, lung recipients. Maximum VO2 in these lung transplant recipients was comparable to previously published values in heart-lung transplant recipients. The factors that limit maximum exercise capacity after lung transplantation deserve further study.

Adult↗
PubMed1990

Surgical aspects of single lung transplantation.

Single lung transplantation is a viable therapeutic option for selected patients with end-stage lung disease. The techniques described, in conjunction with rigorous preoperative physiotherapy, diligent postoperative care, immunosuppression with early avoidance of steroids, and postoperative rehabilitation, have resulted in a gratifying rate of success. Transplantation of the lung involves not a mere technical transfer of the organ from one body to another. It is a complex logistic undertaking requiring a large team of professionals who attend to the many essential components including patient selection, preoperative rehabilitation, donor selection, postoperative care, immunosuppression, rehabilitation, and long-term follow-up. The operation itself represents an integral, but small, component.

Adult↗
PubMed1990

Airway complications after double lung transplantation. Toronto Lung Transplant Group.

We have had success with en bloc double lung transplantation in the management of selected patients with end-stage parenchymal pulmonary disease. Airway complications have been more prevalent in our own experience with double lung transplantation than in reports of combined heart-lung transplantation from other centers. Between November 1986 and March 1989, 16 patients underwent double lung transplantation. Allografts were preserved by topical hypothermic immersion in 12 patients and by pulmonary artery flush with cold crystalloid solution in the most recent four patients. Thirteen patients underwent tracheal anastomosis and the most recent three patients underwent bilateral bronchial anastomoses. Fatal ischemic necrosis of the donor trachea and both main bronchi developed in three patients. Preterminal airway ischemia developed in a patient who had systemic sepsis. Partial anastomotic dehiscence, which went on to form fibrous strictures necessitating endoscopic placement of silicone rubber airway stents, developed in two additional patients. Two other patients had late strictures and required subsequent placement of bifurcation stents. There was no relationship between development of airway complications and gas exchange in the donor lungs, lung ischemic time, early postoperative gas exchange, early postoperative mean pulmonary artery pressure, or frequency of early postoperative rejection. Severe postoperative hypotension occurred in five of eight patients with airway complications and in three of eight patients without airway complications.

Humans↗
PubMed1990

Cardiac innervation after double lung transplantation. Toronto Lung Transplant Group.

Double lung transplantation has been successfully introduced for patients with end-stage pulmonary disease and preserved cardiac function. An advantage of this operation compared with heart-lung transplantation is retention of the recipient's heart. The operative dissection, however, may lead to interruption of sympathetic and parasympathetic pathways to the heart and consequent denervation of the native heart. The cardiac innervation of seven double lung transplant recipients was investigated by the heart rate response to carotid sinus massage, the Valsalva maneuver, intravenous injection of atropine, and exercise. Five single lung and two heart-lung transplant recipients were studied for comparison. Of the seven double lung transplant recipients, three had abnormal responses to carotid sinus massage, six to the strain phase of the Valsalva maneuver, and five to the release phase of the Valsalva maneuver. Three of six double lung transplant recipients tested had no response to intravenous injection of atropine, and five of seven patients had an abnormal recovery of heart rate after maximal exercise. No patient had a normal response to all interventions, and three patients had responses compatible with complete cardiac denervation. It is concluded that cardiac denervation may occur after double lung transplantation, most likely caused by surgical interruption of sympathetic and parasympathetic pathways during dissection of the recipient's trachea.

Adult↗
PubMed1989

Automation of liquid chromatographic techniques for biomedical analysis.

The complete automation of liquid chromatographic (LC) techniques increases their work capacity and makes them more acceptable for biomedical applications. The ability to analyse priority specimens is also advantageous. The areas to be considered in a fully automated LC are reviewed in terms of the analytical operations, the types of processing and the various control systems that can be adopted. In particular, sample preparation and liquid handling are described in detail together with techniques and equipment that can be utilised for their automation. Strategies are given for the rational design of a fully automated LC that can analyse raw samples completely unattended.

Autoanalysis↗
PubMed1989

Record performances at the Boston Marathon: biometeorological factors.

Air temperature and relative humidity have long been suspected of affecting the performance of marathon runners. Though these factors are important in their extremes, we show that other factors are even more indicative of race performances. Performances of the top 3 finishers in the last 30 Boston Marathons were correlated with hourly meteorological data for each race day. These 90 individual performances were classified as: record breaking performances (31), average performances (35), and unusually slow performances (24). The factors that help predict record breaking and unusually slow performances are: (i) wet bulb temperature, (ii) percent sky cover, and (iii) presence or absence of a light precipitation. Record breaking performances are characterized by a wet bulb temperature of less than 7.8 degrees C, and 100% sky cover. A light drizzle is also conducive to better performances. On the other hand, unusually low performances are accompanied by a wet bulb temperature of greater than 7.8 degrees C, and a sky cover of 50% or less. No light precipitation was recorded on any of the unusually slow race days. A graphic analysis clearly shows these relationships to exist. In addition, a multiple regression analysis confirms the importance of these variables. The authors advise that these are reliable predictors; however, when considering marathon races held in various geographical regions and differing climatic regimes, the exact numerical thresholds used here may not apply.

Boston↗
PubMed1989

Closure of chronic postpneumonectomy bronchopleural fistula using the transsternal transpericardial approach.

Thirteen patients with postpneumonectomy bronchopleural fistula occurring 4 months to 10 years after the initial operation have been treated with a transsternal transpericardial approach after the associated empyema had been treated by either tube thoracostomy or open-window thoracostomy. In 10 patients, there were contraindications to using an ipsilateral transthoracic approach. In 10 of the 13 patients, the procedure was successful. Three fistulas recurred; two were quite small, one of them closing spontaneously within 6 months. There were no deaths or clinically significant morbidity related to the transsternal approach. We have found this technique to be most applicable in those patients in whom other procedures have failed to resolve the problem. The technique is relatively simple and safe.

Adult↗
PubMed1989

Use of silicone stents in the management of airway problems.

We report the use of a silicone rubber T tube for the management of complex airway problems in 47 patients during the past 15 years. The tube has been used for palliation in 11 patients with malignant obstruction of the airway, and as the sole treatment or as an adjunct to operation in 36 other patients. Based on the satisfactory results with the use of these tubes, we have utilized silicone stents in the bronchus and bifurcation prostheses at the carina. In the past, we have inserted the T tubes through a tracheostomy stoma. More recently, we have used a technique for endoscopic placement of the T tubes in which the horizontal limb is pulled out through the tracheostomy stoma. This technique facilitates introduction of the tube and maintains the airway during insertion. The use of silicone stents provides an important tool in the management of complicated airway problems, and we anticipate their increased use in the future.

Bronchi↗
PubMed1989

Lung transplantation.

The supply of donor organs remains extremely limited, and improved methods of maintaining the lungs of potential donors to allow for transplantation must be developed. Currently the upper limit of donor lung ischemic even with our "best" preservation techniques is approximately 4 to 6 hours. Improved methods for preservation will increase the supply of suitable lungs and will considerably simplify the logistics of transplantation just as has occurred with liver transplantation. Efficient use of donor organs remains of paramount importance. We recently performed two single-lung transplants utilizing lungs from one donor. Likewise, there is no reason why a lung could not be sent to another center for transplantation if the harvesting group uses only one lung. Sufficient progress has been achieved to date to warrant continued application of lung transplantation for end-stage pulmonary disease. With increasing experience, one can anticipate refinement of techniques and broader application of these procedures. Single lung transplantation, initially restricted to patients with end-stage pulmonary fibrosis, has now been successfully applied to patients with emphysema, pulmonary hypertension, and other conditions. Although transplantation currently can offer real benefit only to a limited number of persons, it serves to create hope for many others. An additional benefit may prove to be the interest and attention that transplantation focuses on patients with end-stage lung disease and on the pathophysiology of chronic respiratory failure. Knowledge gained may ultimately result in the prevention of many of the disorders for which lung transplantation currently offers the only hope.

Graft Rejection↗
PubMed1989

Recovery of elevated atrial natriuretic peptide in pressure-overload right heart failure.

Elevation of the plasma concentrations of immunoreactive atrial natriuretic peptide (ANP) was observed in canine chronic right heart failure (RHF) secondary to right ventricular (RV) pressure overload. Pressure overload on the right heart was gradually increased using an inflatable cuff. The interval between banding and the onset of RHF was 152 +/- 52 days. Seventeen RHF dogs were produced and divided into Group I (n = 11) and Group II (n = 6). At the onset of RHF, Group I dogs were either sacrificed for study of the heart, or unbanded to allow recovery from RHF. The dogs in Group II were maintained in RHF for 3 additional months before being either sacrificed or unbanded. Following unbanding, the ANP level of Group I recovered from 108 +/- 36 (n = 11) to 20 +/- 6 pg/ml (n = 6) at 1 month and was maintained at 27 +/- 7 pg/ml (baseline, 21 +/- 5 pg/ml, n = 11) at 4 months. ANP levels of Group II declined from 165 +/- 55 (n = 6) to 87 +/- 2 pg/ml (n = 3) at 1 month and further decreased to 42 +/- 14 pg/ml (n = 3) 4 months after unbanding. Thus, compared to Group I, Group II had a high ANP level before unbanding and a delay in recovery of the ANP levels despite normalization of the right atrial pressure (RAP). Four months after release of pressure overload, the right atrial hypertrophy persisted in the unbanded dogs; however, Group I unbanded dogs showed a better reversal of the right atrial hypertrophy than Group II unbanded dogs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Single-lung transplantation: imaging features.

The imaging studies obtained after single-lung transplantation in 14 patients were reviewed. The reimplantation response occurred in 13 patients and was an early, transient process, which varied in its manifestations from a subtle perihilar haze to dense consolidation with air bronchograms. Nine episodes of acute rejection, an imprecise clinical diagnosis, occurred in eight of the patients. The associated chest radiographic changes were variable and included basal or diffuse reticular interstitial disease in three cases and basal and/or perihilar consolidation in three cases; no change was detected in three cases. On four occasions, the radiographic changes resolved within 24 hours of intravenous corticosteroid administration. The radiographic findings associated with the reimplantation response and rejection were nonspecific and could have been mistaken for those of fluid overload, atelectasis, mucous plugging, and pneumonia. Bronchial dehiscence was well demonstrated by the finding at computed tomography of extraluminal air adjacent to the bronchial anastomosis. One patient developed multiple pulmonary nodules due to cyclosporine-induced lymphoma.

Acute Disease↗
PubMed1989

Double-lung transplant for advanced chronic obstructive lung disease.

We have achieved repeated success with unilateral lung transplantation for pulmonary fibrosis and have developed an en bloc, double-lung transplant procedure for patients with advanced lung disease of an obstructive or infective nature. Six such procedures have now been performed for end-stage emphysema, and all recipients are alive and well 5 to 15 months later. A seventh transplant for primary pulmonary hypertension was unsuccessful. All recipients were judged to have a life expectancy of 12 to 18 months on the basis of the degree of disability and the documented rate of disease progression. We feel the double-lung procedure is more appropriate than the combined heart-lung transplant for patients requiring replacement of both lungs when right heart function is adequate or deemed recoverable. With this procedure, the recipient is able to retain his or her own heart, avoiding the liabilities associated with cardiac transplantation. Furthermore, the donor heart is available for a separate recipient, and this sharing of the heart and lungs greatly increases the supply of transplantable lungs for patients with end-stage lung disease. Ischemia of the donor airway has been a source of complication, including the one death to date, but this appears to be a surmountable problem.

Adult↗