A mycobacterial 65-kD heat shock protein induces antigen-specific suppression of adjuvant arthritis, but is not itself arthritogenic.

A recombinant (r)65-kD protein from Mycobacterium leprae, at levels far in excess of those present in whole mycobacteria, was unable to induce arthritis. Even when combined with a synthetic adjuvant, CP20961, to mimic the peptidoglycan adjuvant component of the mycobacterial cell wall, the r65-kD protein failed to induce arthritis. Pretreatment with as little as 1 microgram r65-kD protein protected rats against arthritis induced by M. tuberculosis, but this r65-kD protein was markedly less able to protect against arthritis induced by the synthetic adjuvant, CP20961, or type II collagen. The r65-kD protein appears, therefore, to produce an antigen-specific protection against arthritis induced by bacterial cell walls containing the 65-kD protein. Such protection can be overcome, however, by arthritogenic T lymphocytes, suggesting that protection occurs by preventing clonal proliferation of autoreactive T lymphocytes that are induced by the adjuvant properties of mycobacterial cell walls. How the r65-kD protein abrogates this particular adjuvant activity, and the nature of the arthritogenic self antigen(s), remain to be elucidated.

Detection of enteroviral RNA in idiopathic dilated cardiomyopathy and other human cardiac tissues.

Enteroviruses have been considered to be a possible cause of idiopathic dilated cardiomyopathy. We used a polymerase chain reaction methodology for the identification of enteroviral RNA in an attempt to provide evidence of a role for enteroviruses in the pathogenesis of idiopathic dilated cardiomyopathy. The methodology was shown to identify a wide variety of enteroviruses with a sensitivity up to 0.1-1 plaque-forming units/gram of tissue. 5 of 11 cases (45%) of idiopathic dilated cardiomyopathy, as well as 9 of 24 cases (38%) of a wide variety of other cardiac conditions (including normal heart), were positive for enteroviral nucleic acid sequences; all eight control cases of breast carcinoma tested were negative. These results suggest that both the normal and abnormal heart may represent a site of latent or low-grade persistent enteroviral infection, and that the mere presence of enteroviral nucleic acid sequences is not specifically associated with idiopathic dilated cardiomyopathy.

Antiatherogenic effects of L-arginine in the hypercholesterolemic rabbit.

The purpose of this study was to determine if chronic administration of L-arginine, the precursor of endothelium-derived relaxing factor (EDRF), normalizes endothelium-dependent relaxation and decreases atherosclerosis in hypercholesterolemic animals. Male rabbits were fed (a) normal rabbit chow; (b) 1% cholesterol diet; or (c) 1% cholesterol diet supplemented by 2.25% L-arginine HCl in drinking water. Arginine supplementation doubled plasma arginine levels without affecting serum cholesterol values. After 10 wk, the thoracic aorta was harvested for studies of vascular reactivity and histomorphometry. Endothelium-dependent relaxations (to acetylcholine and calcium ionophore A23187) were significantly impaired in thoracic aortae from animals fed a 1% cholesterol diet. By contrast, vessels from hypercholesterolemic animals receiving L-arginine supplementation exhibited significantly improved endothelium-dependent relaxations. Responses to norepinephrine or nitroglycerin were not affected by either dietary intervention. Histomorphometric analysis revealed a reduction in lesion surface area and intimal thickness in thoracic aortae from arginine-supplemented animals compared to those from untreated hypercholesterolemic rabbits. This is the first study to demonstrate that supplementation of dietary L-arginine, the EDRF precursor, improves endothelium-dependent vasorelaxation. More importantly, we have shown that this improvement in EDRF activity is associated with a reduction in atherogenesis.

Effect of verapamil on doxorubicin cardiotoxicity: altered muscle gene expression in cultured neonatal rat cardiomyocytes.

Verapamil reverses multidrug resistance acquired by cancer cells during treatment with chemotherapeutic agents such as doxorubicin by inhibiting the function of P-glycoprotein. Verapamil has also been suggested to potentiate the cardiotoxicity of doxorubicin. We have recently demonstrated that selective inhibition of cardiac muscle gene expression is among the earliest events in doxorubicin cardiotoxicity. To explore the influence of verapamil on doxorubicin cardiotoxicity, we evaluated [14C]-doxorubicin accumulation, cardiac muscle gene expression by Northern blot analysis, and ultrastructural changes in cultured cardiomyocytes in the presence and absence of verapamil. Treatment with a combination of doxorubicin and verapamil for 24 h did not augment doxorubicin accumulation in cardiomyocytes, although substantial augmentation of doxorubicin accumulation by verapamil in cardiac fibroblasts was observed. Further, treatment with verapamil for 24 h did not augment the decrease in expression of muscle genes induced by doxorubicin (myosin light chain 2 slow, troponin I, M isoform creatine kinase). However, we found that verapamil reduced alpha-actin gene expression in a direct, doxorubicin-independent manner. Furthermore, the effect of doxorubicin plus verapamil on alpha-actin gene expression was additive over a wide range of doxorubicin and verapamil concentrations, resulting in a selective augmentation of doxorubicin-induced inhibition of gene expression for this single muscle protein gene. This was reflected in a substantial increase in cardiac myocyte damage when treatment with verapamil and doxorubicin was compared to treatment with doxorubicin alone by thin section electron microscopy. This suggests a possible mechanism by which verapamil may potentiate doxorubicin cardiotoxicity.

Transplant coronary artery disease: a novel model independent of cellular alloimmune response.

BACKGROUND: Allograft coronary atherosclerosis (TxCAD) is the leading cause of death after the first year after transplantation. TxCAD is believed to be a form of chronic rejection of the cardiac allografts. This study was undertaken to determine whether TxCAD could develop in the absence of a cellular alloimmune response. METHODS AND RESULTS: Inbred lean Zucker rats (>26 generations) served as donors and recipients of the cardiac grafts. Donor hearts were explanted at 60 or 90 days. Explanted hearts were processed for coronary artery histological analysis. Cytokine expression was determined by reverse transcription-polymerase chain reaction, and the presence of T cells within the explanted hearts was evaluated by immunohistochemistry. Forty-six transplantations were made, and TxCAD developed in all but one of the transplanted hearts. Overall, one third of the vessels examined were affected by TxCAD, and in roughly half of these vessels, the disease was severe. Native hearts were free of atherosclerosis. Interleukin-2 was absent from the transplanted hearts, and T cells were present in minimal amounts (<1 per low-power field). CONCLUSIONS: TxCAD developed in the absence of a cellular alloimmune response in these genetically similar donors and recipients. The observed TxCAD was significant and comparable to what is found in rat allografting models.

Echocardiographic recognition of paraseptal structures.

Improved echocardiographic equipment provides detailed images of the heart and shows anatomic paraseptal structures previously not well defined. Echocardiograms were analyzed from 33 patients who later underwent cardiac transplantation, and the paraseptal structures noted were correlated with the pathologic specimens. Patterns associated with right ventricular chordae tendineae, the moderator band and the posterior papillary muscle are illustrated. Hypertrophic and fibrotic right ventricular trabeculae and left ventricular paraseptal bands are noted. These structures can be specifically sought and identified using the current generation of echocardiographs, thereby avoiding potential problems of septal definition and measurement.

Evaluation of biopsy classification for rejection: relation to detection of myocardial damage by monoclonal antimyosin antibody imaging.

OBJECTIVES: This study sought to compare the histologic grades of rejection in endomyocardial biopsy specimens with the global estimate of myocardial transplant-related cardiac damage detected by myocardial uptake of monoclonal antimyosin antibodies. BACKGROUND: The diagnosis and treatment of acute cardiac allograft rejection is based on the interpretation of endomyocardial biopsies. Because allograft rejection is a multifocal process and biopsy is obtained from a small area of the right ventricle, sampling error may occur. Global assessment of myocardial damage associated with graft rejection is now possible with the use of antimyosin scintigraphy. The present study was undertaken to compare the histologic grades of rejection in endomyocardial biopsy specimens with the global assessment of transplant-related myocardial damage detected by antimyosin scintigraphy. METHODS: Biopsies (n=395) from 112 patients were independently interpreted by three pathologists in a blinded manner according to the original Stanford four-grade (normal, mild, moderate and severe) and the current International Society of Heart and Lung Transplantation (ISHLT) seven-grade (0, 1A, 1B, 2, 3A, 3B and 4) classifications. The results were correlated with 395 antimyosin studies performed at the time of the biopsies. The heart/lung ratio of antimyosin antibody uptake was used to assess the severity of myocardial damage. RESULTS: In the Stanford biopsy grade classification, significantly higher antimyosin uptake, indicating increasing degrees of myocardial damage, were associated with normal (1.78+/-0.26), mild (1.88+/-0.31) and moderate (1.95+/-0.38) biopsy classifications for rejection (p < 0.01). In the ISHLT classification, significant differences were detected only for antimyosin uptake associated with grades 0 (1.77+/-0.26) and 3A (1.98+/-0.39) but not for intermediate scores (1A, 1B and 2). In view of the similar intensity of antibody uptake among the various grades, ISHLT biopsy scores were regrouped: normal biopsies in grade A; 1A and 1B as grade B; and 2 and 3A as grade C. Antimyosin uptake in grades A, B and C was 1.78+/-0.26, 1.88+/-0.31, 1.95+/-0.38, respectively (p < 0.01). CONCLUSIONS: The current ISHLT seven-grade scoring system does not reflect the progressive severity of myocardial damage associated with heart transplant rejection. Because myocardial damage constitutes the basis of treatment for allograft rejection, there is a need to reevaluate the ISHLT grading system, given its importance for multicenter trials.

Accuracy of biplane and multiplane transesophageal echocardiography in diagnosis of typical acute aortic dissection and intramural hematoma.

OBJECTIVES: The purpose of this study was to evaluate the diagnostic accuracy of biplane and multiplane transesophageal echocardiography in patients with suspected aortic dissection, including intramural hematoma. BACKGROUND: Transesophageal echocardiography is a useful technique for rapid bedside evaluation of patients with suspected acute aortic dissection. The sensitivity of transesophageal echocardiography is high, but the diagnostic accuracy of biplane and multiplane transesophageal echocardiography for dissection and intramural hematoma is less well defined. METHODS: We studied 112 consecutive patients at a major referral center who had undergone biplane or multiplane transesophageal echocardiography to identify aortic dissection. The presence, absence and type of aortic dissection (type A or B, typical dissection or intramural hematoma) were confirmed by operation or autopsy in 60 patients and by other imaging techniques in all. The accuracy of transesophageal echocardiography for ancillary findings of aortic dissection (intimal flap, fenestration and thrombosis) was assessed in the 60 patients with available surgical data. RESULTS: Of the 112 patients, aortic dissection was present in 49 (44%); 10 of these had intramural hematoma (5 with and 5 without involvement of the ascending aorta). Of the remaining 63 patients without dissection, 33 (29%) had aortic aneurysm and 30 (27%) had neither dissection nor aneurysm. The overall sensitivity and specificity of transesophageal echocardiography for the presence of dissection were 98% and 95%, respectively. The specificity for type A and type B dissection was 97% and 99%, respectively. The sensitivity and specificity for intramural hematoma was 90% and 99%, respectively. The accuracy of transesophageal echocardiography for diagnosis of acute significant aortic regurgitation and pericardial tamponade was 100%. CONCLUSIONS: Biplane and multiplane transesophageal echocardiography are highly accurate for prospective identification of the presence and site of aortic dissection, its ancillary findings and major complications in a large series of patients with varied aortic pathology. Intramural hematoma carries a high complication rate and should be treated identically with aortic dissection.

Myocardial involvement in idiopathic hemochromatosis. Morphologic and clinical improvement following venesection.

We describe a 31 year old male patient who presented with severe cardiomyopathy caused by primary hemochromatosis. After a stormy course, complicated by heart failure and severe ventricular arrythmias, improvement in clinical status and myocardial function occurred. Depletion of myocardial iron was documented by the technique of serial endomyocardial biopsy. Myocardial iron stores were not yet depleted when hypoferremia and iron deficiency anemia occurred. This is the first reported study of myocardial morphology in a successfully treated patient with hemochromatotic cardiomyopathy.

Cardiac amyloidosis. Diagnosis by transvenous endomyocardial biopsy.

Endomyocardial tissue, obtained from two patients presenting with restrictive cardiomyopathies, demonstrated amyloid infiltration. The percutaneous transvenous cardiac biopsy technic, using a modified Konno-Sakakibara cardiac bioptome, was safe and quick. Physical examination and catheterization data may not provide a definite differential diagnosis between restrictive and constrictive myocardial disease. Confirmation by biopsy of the cardiac amyloidosis assisted in providing optimum diagnostic and therapeutic care for these patients.

Doxorubicin cardiac toxicity manifesting seven years after treatment. Case report and review.

This report describes a patient treated for lymphoma who had development of doxorubicin (Adriamycin) cardiotoxicity proved by endomyocardial biopsy seven years after treatment. Doxorubicin cardiotoxicity is reviewed with emphasis on the implications of the long latency period for anthracycline cardiotoxicity in patients treated with this widely used antineoplastic agent.

Diverticulum of the left ventricle in hypertrophic cardiomyopathy.

An unusual case of diverticulum of the left ventricle is presented. The most distinctive feature was the presence of a circumferential mid-ventricular contraction ring with histologic abnormalities similar to those described in patients with asymmetric septal hypertrophy. This abnormal ring of tissue obstructed emptying of the ventricular apex and isolated it from the rest of the ventricle. The obstructed apex assumed the appearance of a muscular diverticulum, and the residual portion of the ventricle was markedly diminished in volume. In addition, the abnormal mid-ventricular hypertrophy interfered with papillary muscle function, producing mitral valve prolapse and mitral regurgitation. The patient's age was equally unusual; she was 65 at the time of diagnosis, probably the oldest known patient with ventricular diverticulum. She was treated surgically by transapical myotomy and myectomy of the mid-ventricular contraction ring, in order to increase effective ventricular volume. The relationship of this entity to other types of ventricular deiverticula and aneurysms, and to hypertrophic cardiomyopathy, is discussed.

Early anthracycline cardiotoxicity.

Eight patients in whom cardiac dysfunction developed within four weeks of receiving their first or second course of daunorubicin or doxorubicin are described. Four patients presented with pericarditis; three of these four had evidence of myocardial dysfunction. Histopathologic analysis of these patients was consistent with an acute myocyte damage and secondary inflammatory process. An additional group of four patients presented with symptoms and signs of heart failure. These patients were either elderly or had evidence of previous cardiac disease. One of these patients suffered a myocardial infarction 24 hours after receiving 60 mg/m2 of daunorubicin; earlier doses in the same course had been associated with evidence of myocardial ischemia. We conclude that anthracycline antibiotics may manifest clinically significant cardiotoxicity at total cumulative doses much less than have been associated with chronic cardiomyopathy.

Leukocytic infiltrates in idiopathic dilated cardiomyopathy. A source of confusion with active myocarditis.

The histologic criteria for the endomyocardial biopsy diagnosis of idiopathic dilated cardiomyopathy (IDCM) and active idiopathic/viral myocarditis are unclear. The present study was undertaken to characterize the nature of the inflammatory cell infiltrates in IDCM and thereby refine the differential diagnostic criteria for distinguishing IDCM from myocarditis using endomyocardial biopsy. We examined a mean of 6.2 large random sections from excised hearts of all cardiac transplant recipients at Stanford University with a diagnosis of IDCM, from June 1968 through June 1984. The 108 cases were evaluated for inflammatory cell type, extent, and location. Thirteen percent had no infiltrate, 32.5% had 1-5 foci of at least five inflammatory cells, 47% had 6-30 foci, and 7.5% had 30 or more foci. The infiltrates were primarily lymphocytic; while they were usually in the myocardial parenchyma, infiltrates were also located in zones of fibrosis, the endocardium, the epicardium, and surrounding vessels. Pretransplant biopsies in 56 of the 108 cases were available for review, and 55% of these contained inflammatory cell infiltrates. Agreement between the presence of infiltrates in the biopsy and the resected heart was obtained in 64%. This study highlights the high incidence of inflammatory cell infiltrates in the hearts of patients with IDCM. It reinforces the need for interpreting lymphocytic infiltrates in an endomyocardial biopsy with caution, as their mere presence does not necessarily imply a diagnosis of active myocarditis.

Adriamycin cardiotoxicity: endomyocardial biopsy evidence of enhancement by irradiation.

Endomyocardial biopsies were examined in 12 patients receiving total doses of Adriamycin from 90 to 445 mg/M2. These patients had also received previous mediastinal irradiation (from less than 600 to 5700 rad) over periods varying from 6 months to 14 years prior to the endomyocardial biopsy. Severity of pathological change in these 12 patients was compared with that of dose-matched control patients who had not received mediastinal radiation. The severity of the histopathologic changes was scored on a scale from 0 (normal) to 3 (marked abnormality). The mean score of the group receiving irradiation (2.0 +/- 0.89) was significantly higher than the score in those not irradiated (1.18 +/- 0.23) (p less than 0.001). Morphological demonstration of a "recall phenomenon" of latent radiation changes by Adriamycin was demonstrated in small intramyocardial vessels. This study indicates that radiation, even if remote, enhances Adriamycin-induced cardiomyopathy. Therefore, Adriamycin must be given cautiously in patients who have received previous mediastinal radiotherapy.

Rapamycin inhibits arterial intimal thickening caused by both alloimmune and mechanical injury. Its effect on cellular, growth factor, and cytokine response in injured vessels.

The effect of rapamycin (RPM) on the extent of arterial intimal thickening was determined in rat recipients of orthotopic femoral artery allografts or in rats that had undergone balloon catheter injury to carotid arteries. In untreated rats, neointima comprised approximately 50% of the arterial wall area in both models. Although treatment of allograft recipients for 40 days with 1.5 mg/kg/day RPM was ineffective, a dose of 6 mg/kg/day (days 0-7) followed by 3 mg/kg/day (days 8-39) reduced intimal thickening by 98% (P < 0.0001). The higher RPM dose reduced T cell and macrophage infiltration significantly and decreased the expression of IL-2 receptor, class II Ag, and mRNAs for growth factors and cytokines. Treatment with 1.5 mg/kg/day RPM (days 0-13) after balloon-catheter injury reduced intimal thickening by 45% (P = 0.0254) and substantially decreased macrophage infiltration and expression of class II Ag in the adventitia. Within the neointima, however, mRNAs for platelet-derived growth factor-alpha, basic fibroblast growth factor, and transforming growth factor-beta were still expressed. In summary, we have shown that RPM inhibits not only the vascular response to injury caused by allograft rejection, but also the response to balloon catheter injury. This new information is important to our understanding of: (1) the fundamental processes responsible for intimal thickening regardless of the cause of vascular injury, (2) mechanisms of action of RPM that explain its effects on the response to very different types of vascular injury, and (3) the potentially diverse therapeutic applications of drugs, like RPM, that inhibit the actions of both immune and nonimmune cytokines and growth factors.

Pharmacodynamics of mycophenolic acid in heart allograft recipients: correlation of lymphocyte proliferation and activation with pharmacokinetics and graft histology.

BACKGROUND: Assays of drug blood levels are used for therapeutic immunosuppressive drug monitoring (pharmacokinetics, PK). We monitored lymphocyte functions (pharmacodynamics, PD) in allograft recipients treated with mycophenolic acid (MPA) to determine its mechanisms and the relationships among dose levels, PK, PD, and histological severity of graft rejection. METHODS: Lewis rats transplanted with Brown Norway (BN) rat hearts were treated with different dose levels of MPA for 8, 15, or 29 days at which times grafts were removed and scored for rejection grade. Blood was analyzed (high-performance liquid chromatography) for MPA plasma concentrations (area under the concentration-time curve0-24 hr, C6 hr, trough) and for lymphocyte functions using concanavalin A-stimulated whole blood assays to measure lymphocyte proliferation (tritium labeled thymidine incorporation and flow cytometric bivariate proliferating nuclear cell antigen/DNA analysis) and activation (percent lymphocytes expressing CD25 or CD134). PD values were AUE0-24 hr (area under the PD effect-time curve), maximum inhibition and trough. RESULTS: MPA equipotently suppressed (by flow cytometry) both proliferation and activation and these effects correlated with MPA plasma levels (r2=0.80-0.91). Relationships among MPA dose levels, PK and PD were clear, direct, and reproducible. Correlation coefficients after 8 days of MPA treatment were: 0.90, 0.87, and 0.49 for MPA PK (AUC0-24 hr, C6 hr and trough) versus rejection scores; 0.80-0.89, 0.86-0.92, and 0.25-0.52 for PD flow cytometric assays (AUE0-24 hr, maximum inhibition, and trough) versus rejection scores. CONCLUSIONS: MPA inhibits both lymphocyte proliferation and activation. PD by flow cytometry (FCM) correlates highly with severity of graft rejection, showing that PD of MPA measured in peripheral blood predicts immune cell activity in graft tissue.

Airway pathology in the transplanted rat lung.

Bronchiolitis obliterans has emerged as the most significant long-term complication of human heart-lung transplantation. Possible causes include rejection, infection, altered bronchial circulation, and denervation. We attempted to assess the role of some of these possibilities by reviewing the airway histology in nonimmunosuppressed orthotopic rat left lung allografts in three strain combinations: BN-to-LEW (major histocompatibility complex [MHC]-incompatible) n = 27; (LEW X BN)F1-to-LEW, n = 11; and F344-to-LEW (minor loci-incompatible) n = 18. Fifteen syngeneic transplants (LEW-to-LEW) served as controls. After assigning the lungs to a rejection phase (latent, vascular, alveolar, or destructive), the airway pathology was specifically examined. In the latent phase, only changes attributable to transplantation per se were identified. In the vascular phase in the BN-to-LEW rats and (LEW X BN)F1-to-LEW rats, the bronchioles were surrounded by dense cuffs of activated lymphocytes. The lymphocytic infiltrate then progressively involved the lamina propria and epithelium, where it became associated with focal epithelial cell necrosis. Eventually the epithelium became ulcerated (alveolar phase), and the submucosa and luminal surface became replaced by granulation tissue, which frequently protruded into the lumen in a bronchiolitis obliterans pattern. In the destructive phase the changes were similar to those in the alveolar phase, but were more severe. In the F344-to-LEW rats the airway changes were less prominent, although the remainder of the lungs was at comparable phases of rejection. These changes were not observed in the right (nontransplanted) lungs or the control (LEW-to-LEW) lungs. The findings in these animals suggest that the process of rejection affects the airways and may result in posttransplantation bronchiolitis obliterans.

Myocyte hypertrophy in the transplanted heart. A morphometric analysis.

In order to better define long-term changes in the transplanted heart with respect to the effects of cyclosporine and the ischemic time of the donor heart, endomyocardial biopsies were examined ultrastructurally from 20 cardiac transplant recipients three years posttransplantation. The biopsies were divided into four groups of five based on the donor heart ischemic time in "on-site" versus "distantly procured" hearts and on the immunosuppression protocol: group A: "on site" donor hearts and cyclosporine-based immunosuppression; group B: "on site" donor hearts with conventional immunosuppression (azathioprine-based immunosuppression without cyclosporine); group C: distantly procured donor hearts treated with cyclosporine; and group D: distantly procured donor hearts treated with conventional immunosuppression. All four groups showed a significant increase in the average width of myocytes when compared with normal myocardium, (group A, P less than 0.05; groups B, C, D, P less than 0.01). Also, there was a significant difference between the average widths of myocytes from on-site donor hearts and distantly procured donor hearts (P less than 0.04). There was no significant difference between the average myocyte widths of groups treated with cyclosporine and those with conventional immunosuppression. This study shows that despite the hypertension induced by cyclosporine, myocyte hypertrophy at 3 years posttransplantation does not appear to be significantly greater than in patients treated with conventional immunosuppression. Distantly procured donor hearts have more hypertrophy. Due to the increasing evidence that cardiac hypertrophy per se may predispose to serious ventricular arrhythmias, this study supports the use of on-site as opposed to distantly procured donor hearts.

Combined heart-lung transplantation in the rat. Comparison of thoracic and abdominal operation techniques.

Recently, we developed two techniques for the combined transplantation of heart and the left lung into the left hemithorax of rats. One technique, with two vessel anastomoses, comprised the microsurgical repair of aorta, anterior vena cava, and left main bronchus. With the other, single vessel technique, only the aorta and bronchus were anastomosed. In this study, we determined the function and histology of syngeneic and cyclosporine (CsA)-treated allogeneic grafts transplanted with both techniques, and compared the results with those of heterotopic heart-lung grafts transplanted with a previously described technique for transplantation into the rat's abdomen. The survival rate of rats operated with either of the thoracic transplantation techniques was high (83%). Lungs and hearts of the grafts functioned well for over two months and had normal morphology when the double vessel technique was used. With the single vessel technique, the function of the lungs started to deteriorate from the third postoperative week onward, probably secondary to congestion. The results of thoracic grafts were superior to those of abdominal transplants, where the nonventilated lungs--especially during immunosuppression--were frequently infected. We conclude that these new techniques for thoracic transplantation are most suitable for research of combined heart-lung transplantation.