A call to action in thoracic transplant surgical training.

Thoracic organ recovery and implantation is increasing in complexity. Simultaneously the logistic burden and associated cost is rising. An electronic survey distributed to the surgical directors of thoracic transplant programs in the United States indicated dissatisfaction amongst 72% of respondents with current procurement training and 85% of respondents favored a process for certification in thoracic organ transplantation. These responses highlight concerns for the current paradigm of training in thoracic transplantation. We discuss the implications of advancements in organ retrieval and implant for surgical training and propose that the thoracic transplant community might address the need through formalized training in procurement and certification in thoracic transplantation.

Novel GP64 envelope variants for improved delivery to human airway epithelial cells.

Lentiviral vectors pseudotyped with the baculovirus envelope protein GP64 transduce primary cultures of human airway epithelia (HAE) at their apical surface. Our goal in this study was to harness a directed evolution approach to develop a novel envelope glycoprotein with increased transduction properties for HAE. Using error-prone PCR, a library of GP64 mutants was generated and used to prepare a diverse pool of lentiviral virions pseudotyped with GP64 variants. The library was serially passaged on HAE and three GP64 mutations were recovered. Single-, double- and the triple-combination mutant envelope glycoproteins were compared with wild-type GP64 for their ability to transduce HAE. Our results suggest that lentiviral vectors pseudotyped with evolved GP64 transduced HAE with greater efficiency than wild-type GP64. This effect was not observed in primary cultures of porcine airway epithelial cells, suggesting that the directed evolution protocol was species specific. In summary, our studies indicate that serial passage of a GP64 mutant library yielded specific variants with improved HAE cell tropism, yielding tools with the potential to improve the success of gene therapy for airway diseases.

Ferret lung transplant: an orthotopic model of obliterative bronchiolitis.

Obliterative bronchiolitis (OB) is the primary cause of late morbidity and mortality following lung transplantation. Current animal models do not reliably develop OB pathology. Given the similarities between ferret and human lung biology, we hypothesized an orthotopic ferret lung allograft would develop OB. Orthotopic left lower lobe transplants were successfully performed in 22 outbred domestic ferrets in the absence of immunosuppression (IS; n = 5) and presence of varying IS protocols (n = 17). CT scans were performed to evaluate the allografts. At intervals between 3-6 months the allografts were examined histologically for evidence of acute/chronic rejection. IS protects allografts from acute rejection and early graft loss. Reduction of IS dosage by 50% allowed development of controlled rejection. Allografts developed infiltrates on CT and classic histologic acute rejection and lymphocytic bronchiolitis. Cycling of IS, to induce repeated episodes of controlled rejection, promoted classic histologic hallmarks of OB including fibrosis-associated occlusion of the bronchiolar airways in all allografts of long-term survivors. In conclusion, we have developed an orthotopic lung transplant model in the ferret with documented long-term functional allograft survival. Allografts develop acute rejection and lymphocytic bronchiolitis, similar to humans. Long-term survivors develop histologic changes in the allografts that are hallmarks of OB.

Factors determining outcome after surgical resection of T3 and T4 lung cancers of the superior sulcus.

BACKGROUND: The treatment of superior sulcus lung cancers is evolving and preoperative chemotherapy is increasingly used. To establish a historical benchmark against which new therapies can be assessed, we reviewed our 24-year experience with patients undergoing thoracotomy for lung cancers of the superior sulcus. METHODS: Data were acquired through retrospective chart review. Overall survival was calculated by the method of Kaplan and Meier, and prognostic factors were examined by log rank and Cox proportional hazards modeling. RESULTS: From 1974 to 1998, 225 patients underwent thoracotomy. The patients included 144 men (64%) and 81 women with a median age of 55 years. The majority of patients (55%) received preoperative radiation, but 35% did not have any preoperative treatment. Tumor stages were IIB (T3 N0) in 52%, IIIA in 15%, and IIIB in 27% of patients. Complete resection was achieved in 64% of T3 N0 tumors, 54% of T3 N2 tumors, and 39% of T4 N0 tumors. Operative mortality was 4%. Median survival was 33 months for stage IIB and 12 months for both stages IIIA and IIIB. Actuarial 5-year survivals were 46% for stage IIB, 0% for stage IIIA, and 13% for stage IIIB. By univariate and multivariable analyses, T and N status and complete resection had a significant impact on survival. Locoregional disease was the most common form of relapse. CONCLUSIONS: Our results provide a benchmark against which new treatment regimens can be evaluated. Control of locoregional disease remains the major challenge in treating lung cancers of the superior sulcus. The potential benefit of preoperative chemotherapy or chemoradiotherapy must be assessed by whether it leads to higher rates of complete resection and a lower risk of local relapse.

Immunologic determinants of susceptibility to experimental glomerulonephritis: role of cellular immunity.

To identify the immunologic mechanisms that influence susceptibility to GN, we compared the severity of accelerated anti-glomerular basement membrane (GBM) nephritis between Lewis (LEW) and Brown Norway (BN) rats and analyzed differences in their immune responses to the nephritogenic immunoglobulin. Lewis (LEW) rats preimmunized with sheep IgG developed proliferative GN with marked proteinuria [peak protein excretion (mean +/- SEM) = 85.3 +/- 15.3 mg/24 hr; normal = 6.4 +/- 0.8 mg/24 hr] after receiving a subnephritogenic dose of sheep anti-rat GBM antiserum. Identically treated Brown Norway (BN) rats, on the other hand, had minimal renal pathology and minimal proteinuria (peak protein excretion = 22.6 +/- 3.1 mg/24 hr; normal = 13.0 +/- 0.6 mg/24 hr). Serum titers of rat anti-sheep IgG isotypes and intraglomerular binding of sheep IgG, rat IgG, and rat complement (C3) were comparable in both strains. In contrast, only LEW rats developed a strong cellular immune response to sheep IgG represented by intrarenal T lymphocyte (OX19+) and monocyte (ED1+) accumulation [LEW vs. BN (mean +/- SEM): OX19+ = 0.60 +/- 0.10 vs. 0.14 +/- 0.01 cells/glomerulus, control = 0.02 +/- 0.01; ED1+ = 4.0 +/- 0.4 vs. 1.0 +/- 0.2 cells/glom., control = 0.8 +/- 0.3] and a significant cutaneous delayed-type hypersensitivity (DTH) reaction [LEW versus BN (mean +/- SEM): delta ear thickness = 0.22 +/- 0.02 vs. 0.05 +/- 0.03 mm; control = 0.04 +/- 0.02 mm]. Upon rechallenge with sheep IgG in vitro, LEW splenocytes expressed a T helper 1 (Th1) cytokine pattern (IFN gamma and IL-2 mRNA, but little IL-4 mRNA) which is associated with delayed-type hypersensitivity reactions. BN splenocytes, on the other hand, expressed IL-4 in addition to IL-2 and IFN gamma mRNA that is consistent with an undifferentiated (Th0) cytokine profile. These studies suggest that humoral immunity to heterologous immunoglobulin planted in the kidney is not sufficient for full expression of accelerated anti-GBM nephritis, and that additional cellular immune mechanisms are required. We conclude that susceptibility to accelerated anti-GBM nephritis is strongly influenced by the host's propensity to mount a Th1-type response and DTH reaction to the disease-inciting immunoglobulin.

Anti-inflammatory lymphokine mRNA expression in antibody-induced glomerulonephritis.

T-helper subset 2 (Th2) lymphocytes produce interleukin 4 (IL-4) and IL-10, which exert anti-inflammatory actions on monocytes and macrophages. Th1 lymphocytes, on the other hand, secrete interferon-gamma (IFN gamma) which promotes tissue inflammation. The functional dichotomy between TH1 and Th2 lymphocyte subsets suggests that these cells play a regulatory role in inflammatory disease. The participation of Th subpopulations and their lymphokine products in experimental glomerulonephritis (GN) has not been previously evaluated. In this study, we examined renal expression of Th1 and Th2-type lymphokines in the first 48 hours of passive anti-glomerular basement membrane (anti-GBM) GN in the rate. Using the reverse transcriptase-polymerase chain reaction (RT-PCR) method, apparent increase in expression of both TH1-type (IL-2 and IFN gamma) and Th2-type (IL-4 and IL-10) lymphokine mRNA was observed in glomerular-enriched renal tissue obtained from nephritic rats. Induction of monocyte-derived IL-1 alpha and IL-1 receptor antagonist (IL-1RA) mRNA expression was also detected shorted after initiation of GN. Evidence for influx of mononuclear cells including T lymphocytes into the kidney was noted during the same time period as cytokine mRNA expression. Utilizing a monoclonal anti-rat IL-4 antibody, we also detected interleukin 4-producing cells in the renal cortex 24 hours following induction of GN. these experiments demonstrate for the first time anti-inflammatory lymphokine (IL-4 and IL-10) mRNA expression and IL-4 protein production in the kidney during antibody-mediated GN. WE hypothesize that Th lymphocyte subsets modulate glomerular inflammation by producing lymphokines with opposing actions.