Isolated lung perfusion with doxorubicin prolongs survival in a rodent model of pulmonary metastases

BACKGROUND: We developed a rodent model of unilateral pulmonary metastases to evaluate long-term survival after isolated lung perfusion with doxorubicin. METHODS: In the model development study, on day 0, two groups of F344 rats (n = 15) underwent transient right pulmonary artery occlusion for either 5 or 10 minutes at the time of intravenous injection of methylcholantrene-induced sarcoma cells. On day 14, all animals were sacrificed and lung nodules counted. In the survival study, on day 0, 21 rats received intravenous injection of sarcoma cells with concomitant 10-minute right pulmonary artery occlusion. On day 7, eight rats underwent left isolated lung perfusion with doxorubicin (6.4 mg/kg); five rats underwent perfusion with buffered Hespan; six untreated rats were studied as controls. RESULTS: Ten of fifteen animals (67%) in the model study with 5-minute pulmonary artery occlusion had right-sided tumor nodules. Ten-minute occlusion resulted in a tumor-free right lung in all animals. In the survival study, all animals in the Hespan and control groups died of massive tumor replacement of the left lung, with median survival times of 20 and 18 days, respectively. The median survival time of 36 days for the animals undergoing isolated lung perfusion with doxorubicin was significantly longer (p < 0.00001). The left lung of two of the doxorubicin perfused rats was tumor-free at 6 weeks. CONCLUSIONS: Isolated lung perfusion with doxorubicin results in a durable response and prolongs survival in the treatment of experimental sarcoma pulmonary metastases.     

Halasz syndrome revealed in the newborn infant by pulmonary arterial hypertension. Study of 4 cases

In the 4 studied patients presenting with an Halasz's syndrome, the disease was complicated since the neonatal period by pulmonary arterial hypertension and heart failure. Three out of the 4 infants rapidly died, one after pneumonectomy. The fourth is surviving and benefitted solely from medical cardiotonic treatment. The pathogenesis of early pulmonary arterial hypertension in Halasz's syndrome is complex. The possibly associated cardiac malformations, the persistance of fetal obstructive hypertension due to the increase of the flow in the left pulmonary artery, the left to right shunt induced by the abnormal venous return and predominantly by the systemic blood supply to the right lung, are responsible, at various degrees, for pulmonary hypertension. Among surgical procedures to be proposed, the simple ligation of abnormal arteries which take their origin from the aorta seems to be preferable to pneumonectomy.     

Changes of vasoactive peptides and effects of inhaled nitric oxide after pneumonectomy

To clarify the role of vasoactive peptides in the physiologic response to pneumonectomy, we investigated the changes of atrial (A-type) natriuretic peptide (ANP). C-type natriuretic peptide (CNP), and endothelin-1 (ET-1) levels in the lung and blood after pneumonectomy and the effects of inhaled nitric oxide (NO; 5 ppm) after pneumonectomy in beagle dogs. The concentrations of these peptides in the lung and blood were measured by radioimmunoassay. The dogs in group A (n = 10) were observed without NO inhaling after right pneumonectomy, and the dogs in group B (n = 5) were observed with NO inhaling from 120 to 180 min after right pneumonectomy. After the thoracotomy, right lung tissue was resected for the pre-operative histological control. Tissue from the left lung was obtained at 120 min (5 dogs in group A), at 180 min (5 dogs in group A), and after 60 min of NO inhalation (group B) for the post-operative histological material. Peripheral blood was collected from the femoral artery. The pulmonary arterial pressure (PAP) was significantly increased after pneumonectomy, but rapidly decreased to the same level as the pre-operative stage after NO inhalation. Increases of plasma ANP, lung ANP and lung CNP levels occurred after pneumonectomy, while the ET-1 level was unchanged. Inhaled NO rapidly reduced the plasma ANP, lung ANP and lung CNP. These results indicate that both ANP and CNP act to maintain normotensive homeostatic balance in the pulmonary circulation.     

Distance and the presentation of visual stimuli to birds

Hemodynamic factors have profound influences on blood vessels. To test the hypothesis that hemodynamic conditions modify the pattern of remodeling in response to injury, monocrotaline (MCT) injury in Sprague-Dawley rats was followed 1 week later by left pneumonectomy to increase blood flow to the right lung. Right pulmonary artery remodeling in these MCT plus pneumonectomy animals was compared with animals receiving MCT or pneumonectomy alone. Neointimal changes developed in more than 90% of all right lung intra-acinar vessels 5 weeks after MCT injury (4 weeks after pneumonectomy). Neointimal lesions did not develop in untreated animals or in animals receiving MCT or pneumonectomy only. Animals with a neointimal pattern of remodeling developed severe right ventricular hypertrophy (RVH) whereas animals with a medial hypertrophy pattern of remodeling (MCT only) developed moderate RVH compared with control animals. Neointimal lesions and RVH were similar whether injury preceded pneumonectomy or vice versa. To exclude the possibility that neointimal lesions resulted from injury plus post-pneumonectomy compensatory lung growth, rather than injury plus increased flow, a left subclavian-pulmonary artery anastomosis was substituted for pneumonectomy. Neointimal lesions and severe RVH developed in these animals but were not seen in animals receiving either MCT or anastomosis only. These studies demonstrate an important role for hemodynamics in determining the pattern of pulmonary vascular remodeling after injury.     

Isolated lung perfusion with melphalan and tumor necrosis factor for metastatic pulmonary adenocarcinoma

BACKGROUND: Isolated left lung perfusion with melphalan and human tumor necrosis factor-alpha for pulmonary metastatic adenocarcinoma in the WAG/Rij rat was studied. METHODS: Survival was determined for melphalan, human tumor necrosis-alpha. Lung, pulmonary effluent, and serum melphalan were analyzed by chromatography after isolated lung perfusion or intravenous injection. On day 0, rats were injected with 2.0 x 10(6) CC531S cells intravenously. On day 7, rats underwent sham thoracotomy, received melphalan intravenously, or underwent isolated left lung perfusion with saline, melphalan, tumor necrosis factor, and a combination of the latter two. On day 14, tumor nodules were counted. RESULTS: For the doses of 400 microg tumor necrosis factor, 1,000 microg tumor necrosis factor, or both melphalan and tumor necrosis factor (2 mg + 200 microg), survival rates after contralateral pneumonectomy were 33%, 17%, and 80%, respectively. Survival in all other groups was 100%. Left lung melphalan level was significantly higher after isolated lung perfusion compared to intravenous administration. Significantly fewer left lung nodules were found for 0.5 mg isolated lung perfusion with melphalan (28+/-17) compared to isolated administration (200+/-0) (p = 0.001), and for 1.0 mg intravenous lung perfusion with melphalan (16+/-10) compared to controls (171+/-65) (p = 0.00047). Tumor necrosis factor showed no significant effect. CONCLUSIONS: Isolated lung perfusion with melphalan is an effective treatment for pulmonary metastases from adenocarcinoma in the rat.     

Completion right lower lobectomy for recurrence after left pneumonectomy for metastases

Resection of pulmonary recurrences on the residual lung after pneumonectomy for metastases is exceptional. A 37-year-old woman was submitted to left extended pleuro-pneumonectomy after left leg amputation for fibrosarcoma. At 43 months later, a wedge resection on the right lower lobe was performed followed 32 months later by a further wedge resection in the same lobe. A completion right lower lobectomy for a new recurrence was performed 17 months after the last pulmonary resection. The patient did not develop postoperative complications. She is still alive and free of disease 10 years and 9 months after pneumonectomy and 36 months after completion lobectomy on the residual lung. In highly selected patients, aggressive surgery for metastases on the residual lung can be successfully performed and it can improve survival.     

Flap of the musculus latissimus dorsi to prevent alveolar air leakage from sectional plane of the lung after resection of metastatic pulmonary and chest wall tumor

Alveolar air leakage after pulmonary resection usually heals with adequate pleural drainage, but must be more actively treated if leakage may be severe. If left untreated, the postresection space can lead to empyema. We used a muscle flap to prevent alveolar air leakage from a large sectional plane of the lung resected because of metastases in the lung and chest wall. A 48-year-old man complained of pain and a mass on the right side of his back. He had undergone resection and chemotherapy for clear cell sarcoma that originated on the back of the left hand when 43 years of age, wedge resection of the right lower lobe of the lung for a metastatic pulmonary tumor at 46 years, and lobectomy of the same lobe for a recurrence of the metastatic pulmonary tumor at 47 years. The diagnosis was of a metastatic tumor to the right chest wall with peripheral pulmonary tumors of the right upper and middle lobes. Resection of the chest wall and the lung including the tumors was done. Much air leakage from the extensive sectional plane of the right upper and middle lobes was seen intraoperatively, and this plane was therefore covered with a flap of the musculus latissimus dorsi. Chest tubes were removed on day 7 postoperatively when air leakage was no longer seen. Subcutaneous emphysema, which appeared on day 14 postoperatively, required redrainage of the pleural air space, but pleurodesis was effective. Use of a muscle flap was simple and effective for covering of a sectional plane of the lung, and should be considered when alveolar air leakage may be extensive.     

Mammalian glial cells in culture synthesize acetylcholine

OBJECTIVE: To evaluate the postoperative outcome and long-term results of patients who underwent iterative and extended pulmonary resection leading to completion pneumonectomy for pulmonary metastases. METHODS: From January 1985 to December 1995, 12 patients (mean age 45 years) underwent completion pneumonectomy for pulmonary metastases. These patients represent 1.5% of all pulmonary metastases operated on. There were 5 sarcoma and 7 carcinoma patients. Before completion pneumonectomy, 8 patients had only one pulmonary resection (wedge resection, 2; segmentectomy, 2; lobectomy, 4), 3 patients had two operations and finally, 1 patient had multiple bilateral wedge resections and 1 lobectomy. The median interval time between the last pulmonary resection and completion pneumonectomy was 13.5 months (range 1-24 months). RESULTS: There were 10 left and two right completion pneumonectomies. Three patients had an extended resection (1 carina; 1 chest wall; 1 pleuropneumonectomy). Intrapericardial dissection was used in 3 patients. Two patients died within 30 days of the operation: 1 died of postoperative complications (8.3%) whereas the other died of rapidly evolving metastatic disease. The remaining 10 patients had an uneventful postoperative course. Only 1 patient is still alive and free of disease 69 months after completion pneumonectomy. One patient is alive with disease, another was lost to follow-up; 9 patients died of metastatic disease. The median survival time after completion pneumonectomy was 6 months (range 0-69 months). The estimated 5-year probability of survival was 10% (95% CI: 2-40%). CONCLUSIONS: Indications for both iterative and extended pulmonary resection for PM may be discussed only in highly young selected patients; the extremely poor outcome of our subgroup of patients should lead to even more restrictive indications of CP for pulmonary metastatic disease.     

How the left lung is perfused after ligating the left pulmonary artery in the pig at birth: clinical implications for the hypoperfused lung

The left pulmonary artery and ductus arteriosus were ligated in 14 pigs at birth. Animals were sacrificed at intervals from 2 to 24 weeks of age. In the right lung the pulmonary artery and in the left, either the distal pulmonary artery, bronchial arteries or both were injected. The fixed lung specimens were studied by arteriography, dissection and microscopic examination of serial and random sections of lung tissue. The bronchial arterial circulation to, and within the right lung appeared normal and was similar to that described in the human lung. In the left lung, the bronchial arterial circulation hypertrophied rapidly during the first 2 weeks, and large anastomoses between pulmonary and systemic circulations were found at the same sites as in the normal pig lung. The position and structural characteristics of the anastomosing arteries is described in the different types of broncho-pulmonary connection. In most animals aged 16 weeks or more, peripheral bronchial arteries immediately proximal to the anastomotic sites, developed intimal and medial proliferation. The left lung continued to grow although in all animals it was small. The axial pulmonary artery and its branches became smaller with age. These findings help explain how the lung is perfused and grows in children with congenital heart disease and an acquired collateral pulmonary arterial circulation.     

Chondrosarcoma: a case report with left atrial involvement and systemic embolization

A 26-year-old white man underwent amputation of the right lower extremity for a chondrosarcoma of the distal femur. Eleven years later, after a long symptom-free interval, he was hospitalized for rapidly progressive dyspnea, pleuritic chest pain, and hemoptysis resulting from a large pulmonary metastasis that had extended directly to the left atrium via the pulmonary vein. Within 24 hours of hospitalization, obstruction of the left commom iliac artery by tumor embolus necessitated embolectomy. This represents the second report of a metastatic chondrosarcoma involving the left atrium. The case presented clinically as an atrial myxoma and disseminated via the systemic circulation with a rapidly downhill course therafter.     

Respiratory insufficiency and absent left radial pulse after hemicolectomy

A 65 year old female developed right thoracic pain, productive cough and fever four weeks after hemicolectomy because of a cancer of the sigmoid. In spite of antibiotic treatment the condition of the patient deteriorated and she was admitted to the hospital with pneumonia of an upper lobe. Chest X-ray visualized prominent proximal pulmonary arteries. Progressive respiratory failure developed and blood gas analysis revealed hypocapnic hypoxemia. The patient had to be intubated and ventilated mechanically. Later, left arm blood pressure measurements could no longer be taken and the radial pulse was missing. Thereafter, an ischemic syndrome of the right leg developed. Embolectomy from the superficial femoral artery was carried out the same day. The patient died five days later. Autopsy revealed an almost complete occlusion of the pulmonary arteries. The organization of thrombotic material indicated recurrence. Emboli were also found in the systemic circulation. A large patent foramen ovale together with signs of pulmonary arterial hypertension are indicative of paradoxical thromboembolism.     

Cancer resection on the residual lung after pneumonectomy for bronchogenic carcinoma

BACKGROUND: After pneumonectomy for bronchogenic carcinoma, the residual lung may be the site of a new lung cancer or metastatic spread. METHODS: From 1989 to 1995, 13 patients with carcinoma on the residual lung after pneumonectomy for lung cancer were operated on. Three segmentectomies and 7 simple wedge resections were performed, 2 patients had multiple wedge resections, and 1 patient had an exploratory thoracotomy. Nine patients had a primary metachronous bronchogenic carcinoma, 3 had metastases from bronchogenic carcinoma, and no definite conclusion was reached in 1 case. RESULTS: No postoperative mortality was observed. Four patients had postoperative complications. The mean postoperative hospital stay was 14 days. Seven patients are alive, including 5 patients without evidence of disease. Six patients died of their disease, all with pulmonary recurrences. The overall median survival was 19 months, with a probability of survival at 3 years (Kaplan-Meier) of 46% (95% confidence interval, 22% to 73%). CONCLUSIONS: Limited pulmonary resection for lung cancer after pneumonectomy for bronchogenic carcinoma is feasible with very low morbidity. In highly selected patients, surgical resection might prolong survival.     

Prolonged survival following cerebral metastasis from pulmonary cancer

A case is reported of prolonged survival after pneumonectomy for anaplastic carcinoma of the left lung and excision of metastatic anaplastic carcinoma of the brain. The patient has survived for 8 years, 6 months after the lung surgery and 7 years after the brain surgery.     

Cardiopulmonary adaptations to pneumonectomy in dogs. IV. Membrane diffusing capacity and capillary blood volume

Lung diffusing capacity for carbon monoxide (DLco) and its components, membrane diffusing capacity (Dmco) and capillary blood volume (Vc), as well as pulmonary blood flow (Qc), were measured at rest at several lung volumes and during treadmill exercise by a rebreathing technique in four adult dogs after right pneumonectomy (R-PNX) and in six matched control dogs (Sham) 6-12 mo after surgery. In both groups, lung inflation at rest was associated with a small increase in DLco and Dmco but not in Vc. After R-PNX, total DLco was lower by 30% at peak exercise compared with control values. When compared with DLco in a normal left lung, DLco in the remaining lung continued to increase along the normal relationship with respect to Qc up to a cardiac output equivalent to 34 l/min through both lungs of the Sham dog. There was no evidence of an upper limit of DLco being reached. The augmentation of DLco from rest to exercise was associated with corresponding increases in Dmco and Vc; after R-PNX, both Dmco and Vc continued to increase with respect to Qc along similar relationships as in control dogs without reaching an upper limit, suggesting a much larger alveolar-capillary reserve for gas exchange by diffusion than previously recognized. At higher levels of blood flow through the remaining lung, DLco was greater in adult dogs after R-PNX than after left pneumonectomy (Carlin et al. J. Appl. Physiol. 70: 135-142, 1991), suggesting that additional sources of compensation, e.g., lung growth, exist after removal of > 50% of lung.     

Progression of interproximal caries in the primary dentition

In the patients with invasion to the aortic window, we performed operation via median sternotomy combined with anteroaxillar thoracotomy. In such patients with T4 invasion, conventional pneumonectomy could not be performed because of the extensive invasion near the main pulmonary artery trunk. In these patients in this study, complete resection of the involved pulmonary artery could be performed using a vascular clamp without CP bypass. Operative technique was as follows: first, the pericardium was opened and taping of the aorta was applied. When the uninvolved part of the intrapericardial pulmonary artery was long enough to cut, we could use a stapling device, but the stapling device could not be used in many cases because the length of the uninvolved segment was too short to cut the left pulmonary artery. In order to carry out complete resection, it was necessary to clamp the central part of the main pulmonary artery diagonally from the left lower side to the right upper side. The pulmonary arterial stump was closed with continuous 4-0 monofilament mattress and over and over suture. We recommend an aggressive surgical approach for the tumor with invasion to the aortic window, because the prognosis is dismal in nonresected locally advanced lung cancer.     

Ischemic preconditioning enhances donor lung preservation in the rat

BACKGROUND: Ischemic preconditioning achieved by brief periods of ischemia and reperfusion before a prolonged period of ischemia can significantly reduce the extent of cardiac damage in many mammalian species and human beings. In this study we used a rat model of single lung transplantation to show that ischemic preconditioning also occurs in the lung. METHODS: Rats randomly selected for ischemic preconditioning had their left main bronchus and pulmonary artery occluded for 5 minutes, followed by 10 minutes of reperfusion and ventilation. Lungs of control rats were ventilated for 15 minutes. The lungs were perfused with University of Wisconsin solution, then heart and lungs were excised en bloc and stored in University of Wisconsin solution at 0 degree C for 6 or 12 hours. After left pneumonectomy, the left lung of the donor was then implanted into the recipient via left thoracotomy. After 1 hour of ventilation and reperfusion, a right pneumonectomy was performed making the animal completely dependent on the transplanted lung. Samples of arterial blood from the left ventricle were then taken for arterial oxygen tension and arterial carbon dioxide tension determination. Water contents of the donor lungs were measured before and after reperfusion. Thiobarbituric acid reactive substances were measured in the right donor lung after storage. RESULTS: Lungs transplanted after 12 hours of storage had profoundly impaired gas exchange (arterial oxygen tension = 34 +/- 5; arterial carbon dioxide tension = 69 +/- 7 mm Hg) compared with the normal levels in the 6-hour storage group (arterial oxygen tension = 308 +/- 22; arterial carbon dioxide tension = 17 +/- 1 mm Hg). Ischemic preconditioning significantly improved gas exchange in the 12-hour storage group (arterial oxygen tension = 83 +/- 11; arterial carbon dioxide tension = 40 +/- 4 mm Hg). Ischemic preconditioning also significantly decreased thiobarbituric acid reactive substances formation at both 6- and 12-hour storage. CONCLUSIONS: These results show that the phenomenon of ischemic preconditioning occurs in the lung and that it may reduce injury to the donor lung during prolonged cold ischemic storage.     

Complete occlusion of all three main coronary arteries, with survival dependent on two septal arteries

A 68-year-old Asian gentleman presented with limiting angina pectoris following myocardial infarction. Coronary angiography demonstrated complete occlusion of the left anterior descending artery after the first septal, the proximal right coronary artery and also the proximal part of the circumflex. The myocardial blood supply was wholly dependent on two septal arteries.     

Cardio-pulmonary function during acute unilateral occlusion of the pulmonary artery in broilers fed diets containing normal or high levels of arginine-HCl

Cardio-pulmonary function was measured in male broilers reared on diets formulated to contain 1.5% arginine (NORMAL group) or 2.5% arginine (ARGININE group). A snare placed around the right pulmonary artery permitted acute shunting of the entire cardiac output (CO) through the left pulmonary artery, resulting in sustained increases in blood flow (BF) through the left lung in both groups. The unilateral increase in BF was accompanied by sustained increases in pulmonary arterial pressure (PAP) and pulmonary vascular resistance (PVR) in the NORMAL group. However, following initial transient increases in PAP and PVR in the ARGININE group, subsequent pulmonary vasodilation gradually reduced PVR, and thus PAP, in spite of the ongoing elevation of BF through the left lung. The capacity of the pulmonary vasculature in the ARGININE group to accommodate an increased BF at a normal PAP accounts for the previously reported lower incidence of pulmonary hypertension syndrome (PHS, ascites) in cold-stressed broilers fed supplemental dietary arginine. Hypoxemia and respiratory acidosis ensued rapidly in both groups after tightening the pulmonary artery snare, in spite of a compensatory increase in the respiratory rate. The gradual return of PVR and PAP to presnare levels in the ARGININE group did not eliminate the concurrent ventilation-perfusion mismatch caused by the increased rate of BF through the left lung. Tightening the pulmonary artery snare caused mean systemic arterial pressure (MAP) to drop from control levels of approximately 98 mm Hg to sustained hypotensive levels of approximately 65 mm Hg in both groups. This systemic hypotension was caused by decreases in CO and total peripheral resistance (TPR). The reduction in CO were caused by reduction in stroke volume (SV) rather than heart rate (HR), suggesting that acutely tightening the pulmonary artery snare increased PVR sufficiently to impede left ventricular filling. Accordingly, the maximum increment in PAP attainable by the right ventricle during acute increases in PVR apparently was inadequate to propel the entire CO through the pulmonary vasculature, setting the stage for the congestive right-sided pooling of blood routinely associated with PHS in broilers.     

Increased pulmonary blood flow produces endothelial cell dysfunction in neonatal swine

BACKGROUND: The mechanisms by which increased pulmonary blood flow results in pulmonary hypertension have not been determined. METHODS: To determine if increased pulmonary blood flow produces endothelial dysfunction that precedes vascular remodeling and smooth muscle proliferation, neonatal swine (n = 12) (age, 6.1+/-0.5 days) underwent ligation of the left pulmonary artery (LPA) to increase blood flow to the right lung. At 12 weeks of age, endothelium-dependent vasodilatation was assessed by acetylcholine infusion and endothelium-independent vasodilatation by inhaled nitric oxide (NO) in the LPA group and age-matched controls (CON) (n = 11). RESULTS: Mean pulmonary artery pressure was 24.1+/-3.0 mm Hg in the LPA group and 20.8+/-1.9 mm Hg in the CON group (p < 0.1). Pulmonary vascular resistance was 13.2+/-2.2 Wood units in the LPA group and 5.8+/-0.8 Wood units in the CON group (p = 0.001). Acute occlusion of the left pulmonary artery in the CON group increased pulmonary vascular resistance to 6.9+/-3.9 Wood units (p = 0.04). Administration of acetylcholine in the CON group after preconstriction with the thromboxane A2 analogue U46619 resulted in a 30.6%+/-5.4% decrease in pulmonary vascular resistance. In the LPA group, acetylcholine produced paradoxical vasoconstriction and a 15.4%+/-4.1% increase in pulmonary vascular resistance (p < 0.001 versus CON) indicating loss of endothelium-dependent vasodilatation. Nitric oxide decreased pulmonary vascular resistance by 41.9%+/-3.3% in the CON group and 30.8%+/-2.7% in the LPA group (p = 0.04 versus CON), indicating preserved endothelium-independent vasodilatation in both groups. Morphometric analysis was performed in 4 animals from each group. Medial wall thickness as percent of external diameter of small arteries (<100 microm) was the same in both groups (6.4%+/-0.4% in the LPA group versus 6.6% +/-0.4% in the CON animals; p > 0.1). CONCLUSIONS: Increased pulmonary blood flow in immature animals produces endothelial cell dysfunction with loss of endothelium-dependent vasodilatation before the onset of pulmonary vascular remodeling. Subsequent smooth muscle proliferation may be mediated by endothelium-derived factors.     

Natriuretic peptides in the lung modulated by pneumonectomy

BACKGROUND: Natriuretic peptides are vasodilator hormones involved in the regulation of blood pressure and volume homeostasis. However, the mechanism of these peptides after pneumonectomy remains obscure. METHODS: We investigated changes in the pulmonary arterial pressure and the localization and changes in the atrial (A-type) natriuretic peptide (ANP) and the C-type natriuretic peptide (CNP) in the lung, using immunohistochemistry and radioimmunoassay (RIA) in anesthetized dogs. Furthermore, we examined guanosine 3', 5'-monophosphate (cGMP) levels in plasma and in the contralateral lung. RESULTS: Pulmonary arterial pressure was significantly increased after pneumonectomy. The immunoreactivities of both ANP and CNP were detected in the endothelium of the pulmonary artery. In the contralateral lung, the concentrations of ANP and CNP were both significantly increased. In plasma, only ANP levels were significantly increased. In contrast, the plasma and lung cGMP levels were significantly reduced after pneumonectomy. CONCLUSIONS: We postulate that the processes from secretion in the vascular endothelial cells to the action via ANP and CNP receptors are effected in the contralateral lung tissue at the acute stage of pneumonectomy.