Improvement of lung preservation -- from experiment to clinical practice

BACKGROUND: Reperfusion injury represents a severe early complication following lung transplantation. Among the pathogenetic factors, the high potassium content of Euro-Collins(reg) solution is discussed. MATERIAL AND METHODS: In a pig model of orthotopic left-sided lung transplantation we investigated the effect of Euro-Collins solution (EC: n = 6) versus low potassium dextran (LPD: Perfadex: n = 6). Sham-operated (n = 6) animals served as control. Transplant function, cellular energy metabolism and endothelial morphology served as parameters. In a clinical investigation, 124 patients were evaluated following single (EC: n = 31; LPD n = 37) or double (EC: n = 17; LPD n = 39) lung transplantation, whose organs where preserved with EC (n = 48) or LPD (n = 76). Duration of ischemia, duration of ventilation and stay on ICU were registered. Primary transplant function was evaluated according to AaDO(2) values. Cause of early death (30 days) was declared. RESULTS: Experimental results: After flush with EC and 18 h ischemia, a reduction of tissue ATP content (p < 0.01 vs inital value and LPD) was noted. Endothelial damage after ischemia was severe (p < 0.05 vs control), paO(2) was significantly decreased. Clinical results: In the LPD group, duration of ischemia was longer for the grafts transplanted first (SLTx and DLTx: p = 0.0009) as well as second (2. organ DLTx: p = 0.045). Primary transplant function was improved (day 0: SLTx: p = 0.0015; DLTx: p = 0.0095, both vs EC). Duration of ventilation and stay on ICU were shorter (n.s.). Reperfusion injury-associated death was reduced from 8% (EC) to 0 (LPD). CONCLUSION: In experimental lung preservation, LPD lead to an improved graft function. These results were confirmed in clinical lung transplantation. Clinical lung preservation, therefore, should be carried out by use of LPD.     

The femoral hernia

BACKGROUND: We designed a study to determine the rate of intra- and postoperative complications as well as the rate of recurrences in elective operated femoral hernias treated via the laparoscopic technique. METHODS: Between 1993 and 1998, we performed 1,097 operations in our department using the laparoscopic transabdominal preperitoneal (TAPP) technique. Femoral hernias amounted to only 4.6% (51 cases) of these patients. The male/female ratio was 1:2. The data concerning the operations and pre- and postoperative treatment were recorded prospectively. The patients were followed up at 2 weeks and 1 year after the operation. RESULTS: We encountered one intraoperative bladder lesion, one subcutaneous port site infection, two postoperative hematomas that required reoperation, and two nerve irritation syndromes, which disappeared spontaneously after 6 months. Two patients developed an ileus; one required laparoscopic reintervention, and the other was treated with conventional open reoperation and intestinal resection. There were no recurrences. CONCLUSIONS: The application of the laparoscopic approach to the treatment of femoral hernias using the TAPP technique in nonemergency situations is highly effective. To date, we have seen no recurrences. Although the rate of major complications is low, current surgical techniques need to be perfected to avoid the type of complication recognized in this study.     

Minimal residual disease in gastric cancer: evidence of an independent prognostic relevance of urokinase receptor expression by disseminated tumor cells in the bone marrow.

PURPOSE: To study the invasion-related molecule urokinase-type plasminogen activator receptor (u-PAR) expressed by disseminated tumor cells as a biologic predictor of poor survival in a large prospective series of patients with gastric cancer. PATIENTS AND METHODS: In 156 gastric cancer patients (prospective series), disseminated tumor cells in the bone marrow and the u-PAR expressed by these tumor cells were determined by cytokeratin (CK) 18 immunocytochemistry and u-PAR/CK18 double immunocytochemistry. RESULTS: In contrast to the mere detection of disseminated tumor cells at primary surgery, the additional evidence of u-PAR on these cells correlated significantly with pathologic T stage (P =.0474) and the expression of u-PAR (P =.0093) and plasminogen-activator inhibitor 1 (P =.0145) in the primary tumor (immunohistochemistry, chi(2)). Kaplan-Meier analysis revealed no association with prognosis for the mere detection of disseminated tumor cells. In contrast, a significant association was seen between detection of u-PAR on these cells and shorter disease-free (P <.0001) and overall survival (P <.0001). Multivariate analysis revealed that u-PAR on disseminated tumor cells at the time of primary surgery is an independent prognostic factor for disease-free (95% confidence interval [CI], 1.72 to 3.21; P =.024) and overall survival (P =.0049; relative risk, 2.89; 95% CI, 1.92 to 4.30). CONCLUSION: This is the first large study to show that u-PAR, detected on disseminated tumor cells in the bone marrow, is an independent prognostic parameter in gastric cancer, in contrast to the mere detection of minimal residual disease (MRD). u-PAR may be a promising marker to define a critical subpopulation of disseminated tumor cells and a target to eliminate MRD. Molecular phenotyping of MRD is critical for defining its individual clinical relevance.     

Mediators of antigen-induced gastrin release: role of antigen-antibody complexes and the complement system

That orally administered antigen was shown to induce gastrin release in immunized animals was a new aspect of gastrointestinal physiology. The mediators responsible for this immunological effect are still unclear. In an attempt to discover more about the mechanisms regarding antigen-induced gastrin release, we developed an in vitro system where fragments of rat antral mucosa were challenged. This makes it possible to determine the role of antigen-antibody complexes and the complement system in the mechanism of antigen-induced gastrin release. Wistar rats were immunized in vivo with NIP-OVA and mucosal fragments were challenged in vitro with NIP-HGG. Gastrin was determined after a preincubation and a challenged incubation period without supernatants. After antigenic challenge, supernatants were used for in vitro challenge in order to rule out the presence of a soluble mediator and activation of complement. In a second group of experiments Wistar rats were used to study in vitro the release of specific antibodies after antigenic challenge. With this experimental design we were able to show increased gastrin secretion after antigenic challenge in vitro in the presence of intact tissue. It is shown that the increased gastrin release is most probably mediated by activation of the complement system in the presence of antigen-antibody complexes. These are built up by specific anti-NIP antibodies and NIP-HGG used for the challenge. The complement system might be the final pathway of the observed in-creased gastrin release.     

Intraoperative Milzverletzung — Organerhaltung um jeden Preis?

Ohne Zusammenfassung Redaktion: J. R. Siewert Chirurgische Klinik und Poliklinik der Technischen Universität, Klinikum rechts der Isar, Ismaninger Straße 22, D-81675 München     

Dynamics of immunoglobulin synthesis after major trauma. Influence of recombinant lymphokines

Major mechanical trauma causes a severe suppression of B-cell differentiation and IgM synthesis in mononuclear leukocyte cultures. In this study the effect of recombinant lymphokines and physiologic T-cell supernatants on B-cell differentiation was investigated. The influence of potentially suppressing monocytes and positive regulatory T-lymphocytes was eliminated using purified B-cell cultures. Antigen-induced IgM synthesis was reduced on all days following trauma. Addition of recombinant interleukin 2 or T-cell supernatant enhanced but did not restore IgM synthesis. Although recombinant interleukin 4 and recombinant interferon gamma had a suppressive effect on IgM synthesis in controls, both lymphokines were ineffective in the patients' IgM synthesis. Spontaneous IgG production in patients was dramatically elevated, and the addition of lymphokines did not show any enhancing effect in patients. These results demonstrate that the IgM/IgG shift observed in peripheral blood mononuclear cell cultures also exists in purified B-cell cultures. Interleukin 2 partially restored suppressed IgM synthesis, while interleukin 4 and interferon gamma were ineffective in patients' B-cell differentiation. Interleukin 2 was the most effective lymphokine for the induction of Ig synthesis. These results lead us to conclude that the altered B-cell metabolism might also be responsible for the suppression of humoral immunity following trauma.     

Tracheoesophageal fistula after blunt thoracic trauma: recognition and treatment

Three cases of tracheoesophageal fistula as a result of nonpenetrating chest trauma were surgically repaired. Another 31 cases were found in the literature. 'Thrown against a steering wheel' was the cause of injury in the majority of patients. Though the fistula became characteristically symptomatic 3 to 7 days after the accident, the diagnosis was often delayed for several months. No patient recovered without operation. After demarcation of the area of contusion and necrosis, especially in the esophagus wall, surgical repair is the therapy of choice.     

Carboxymethylcellulose-stabilized collagenous rhOP-1 device-a novel carrier biomaterial for the repair of mandibular continuity defects

Human recombinant osteogenic protein-1 (rhOP-1) is osteoinductive. Efforts are made to develop carrier biomaterials with improved space-keeping properties. Bovine collagen type I matrix charged with rhOP-1 was suggested to be an advantageous device of relative liquid quality. We hypothesized that the addition of carboxymethylcellulose (CMC) may stabilize the device and facilitate the regeneration of mandibular continuity defects without further addition of mineralized carrier materials. To test this hypothesis, the anatomical shape, functional remodeling, and mechanical stability of such bony regenerates were evaluated in the course of an animal experiment. Mandibular continuity defects of 5 cm in size were created in five G?ttingen minipigs on one side (contralateral hemimandible: control) and bridged with titanium plates. Four animals were treated with the rhOP-1 device (3000 microg rhOP-1, 2 g collagen, 1 g CMC), and one animal was treated with a placebo device omitting rhOP-1. After 12 weeks of experimental period, bony continuity was reestablished in rhOP-1-treated hemimandibles. The bony regenerates were of good anatomical shape, volume, and functional remodeling. Placebo treatment led to insufficient bony regenerates of significant lower bone volume (volume in 3D-CT scan 29.81 cm(3) vs 8.85 cm(3)). To produce 1 mm of bending, 1972 N were needed for rhOP-1-treated hemimandibles, 2617 N for control hemimandibles, and 642 N for the placebo treated hemimandible. CMC stabilization of collagen carrier biomaterials for rhOP-1 provides good plasticity as well as excellent space-keeping properties and may not interfere with osteoinduction. The results of this preliminary study suggest that the applied rhOP-1 device offers a potential option for further studies on the reconstruction of mandibular defects.     

Detrimental Immunologic Effects of Preoperative Chemoradiotherapy in Advanced Rectal Cancer

PURPOSE: Preoperative chemoradiotherapy for advanced rectal cancer has been an important therapeutic tool to improve the long-term results of curative resection. It is not known whether preoperative chemoradiotherapy for advanced rectal cancer influences the perioperative course of immune parameters. METHODS: Thirty patients with rectal cancer underwent surgery with (study group, n = 15) or without (control group, n = 15) preoperative chemoradiotherapy (2 cycles of 5-fluorouracil, 45 Gy). Blood samples were taken before neoadjuvant therapy, preoperatively, and on Days 1, 2, and 5 after surgery. Cell numbers of lymphocyte subpopulations, granulocytes, monocytes, and natural killer cells were determined by flow cytometry; tumor necrosis factor- and interleukin-6 serum levels were measured with enzyme-linked immunosorbent assay. RESULTS: Significant differences between study and control patients (P < 0.05) were detected regarding circulating interleukin-6 and tumor necrosis factor- levels, with depression of the proinflammatory response to surgery in study patients. Similarly, granulocytosis and monocytosis after surgery were significantly lower in patients after neoadjuvant therapy. Furthermore, cell counts of total T lymphocytes, T helper cells, B lymphocytes, and natural killer cells were significantly reduced after preoperative chemoradiotherapy. This depression of cell-mediated immunity in study patients was even more pronounced after surgery. CONCLUSIONS: Preoperative chemoradiotherapy for advanced rectal cancer results in a significant preoperative and postoperative immune dysfunction as indicated by depression of lymphocyte subpopulations, monocytes, granulocytes, and proinflammatory cytokine release. These findings are of importance because increased perioperative morbidity and mortality rates have been observed after preoperative chemoradiotherapy.     

MHC class I negative phenotype of disseminated tumor cells in bone marrow is associated with poor survival in R0M0 breast cancer patients

Changing the major histocompatibility complex (MHC) class I phenotype is a pivotal strategy of tumor cells to circumvent an effective immune response and is associated with tumor progression in cancer patients. Epithelial cells in bone marrow have been detected in various tumor types, but the clinical observation that only a portion of the patients with a positive bone marrow status develops solid bone metastasis suggests a certain molecular equipment of the isolated tumor cells as a prerequisite for metastatic formation. In the present study the prognostic impact of the MHC class I phenotype of disseminated epithelial cells in bone marrow was evaluated in a cohort of 30 curatively resected (R0) patients without distant metastases (M0) (designated R0M0) who had minimal residual disease. Immunocytochemical analysis using the alkaline/anti-alkaline immunogold double staining procedure revealed a heterogeneous MHC class I expression profile [monoclonal antibody (mAb) W6/32] of the epithelial cells (mAb CK2). In 16 patients (53.3%) all epithelial cells were human leukocyte antigen (HLA) class I-positive (CK2+//W6/32+ phenotype). Eight patients (26.7%) showed complete loss of the HLA class I molecules (CK2+//W6/32- phenotype) and in 6 patients (20%) partial loss of HLA class I expression was found (CK2+//W6/32+ and - phenotype). CK2+ cells with the HLA class I negative phenotype (CK2+//W6/32- phenotype and CK2+//W6/32+ and - phenotype) were often derived from poorly differentiated (G3) primary breast carcinomas (p = 0.036) and were associated with short survival of the R0M0 patients (follow-up 15-98 months, log rank p = 0.072). These findings support the necessity to develop immmunotherapeutic strategies leading to the restoration of MHC class I positive phenotype.