Hemostatic efficacy of TachoSil in liver resection compared with argon beam coagulator treatment: an open, randomized, prospective, multicenter, parallel-group trial.

BACKGROUND: The aim of this trial was to confirm previous results demonstrating the efficacy and safety of a fixed combination tissue sealant versus argon beam coagulation (ABC) treatment in liver resection. METHODS: This trial was designed as an international, multicenter, randomized, controlled surgical trial with 2 parallel groups. Patients were eligible for intra-operative randomization after elective resection of ≥ 1 liver segment and primary hemostasis. The primary end point was the time to hemostasis after starting the randomized intervention to obtain secondary hemostasis. Secondary end points were drainage duration, volume, and content. Adverse events were collected to evaluate the safety of treatments. The trial was registered internationally (Eudract number 2008-006407-23). RESULTS: Among 119 patients (60 TachoSil and 59 ABC) randomized in 10 tertiary care centers in Europe, the mean time to hemostasis was less when TachoSil was used (3.6 minutes) compared with ABC (5.0 minutes; P = .0018). The estimated ratio of mean time to hemostasis for TachoSil/ABC was 0.61 (95% confidence interval, 0.47-0.80; P = .0003). Postoperative drainage volume, drainage fluid, and drainage duration did not differ between the 2 groups. Mortality (2 vs 4 patients) and adverse reactions (24 vs 28 patients) for TachoSil versus ABC did not differ. CONCLUSION: This trial confirmed that TachoSil achieved significantly faster hemostasis after liver resection compared with ABC. Postoperative morbidity and mortality remained unchanged between both groups.

A microsurgical approach to hepatic and extrahepatic antigen presentation and its effects on the migration pattern of activated CD8(+) T cells.

CD8+T lymphocytes activated in peripheral lymphoid organs are believed to preferentially localize to the hepatic sinusoids, but the role of antigen in the process has been difficult to define. To create experimental mice in which the liver was unique in lacking the ability to present antigen, we adopted a novel microsurgical approach, in which the site of antigen presentation was restricted by orthotopic mouse liver transplantation of MHC Class I-disparate livers. We used two related mouse strains, of which the wild-type strain could present an injectable model antigen, while a mutant strain could not. By transplanting mutant-strain livers into wild type recipients, we were able to evaluate the absence of intrahepatic parenchymal antigen presentation on CD8+ T cell activation, differentiation, and migration. This illustrates that orthotopic liver transplantation is a powerful technique for addressing issues of antigen presentation.

Quantitative dynamic contrast-enhanced sonography of hepatic tumors.

Liver tumors are defined using quantitative dynamic contrast-enhanced ultrasound compared to histological diagnosis, respectively, long-term follow-ups. Forty-two focal liver lesions in 39 patients were examined by contrast harmonic imaging over a period of 2 min after bolus injection of 10-ml galactose-based contrast agent. Vascular enhancement was quantified by using a dedicated software that allowed us to place representative regions of interest (ROI) in the center of the lesion, in the complete lesion, in regular liver parenchyma and in representative liver vessels (artery, vein and portal vein). Peak enhancement was judged to be either in the arterial, portal venous or in the late phase of liver perfusion. The lesion was described as hypovascular, isovascular and hypervascular compared to liver parenchyma. Contrast uptake was described as centrifugal or centripetal and peripheral or homogenous, respectively. Characterization of the lesions was performed unenhanced and after contrast by four independent specialists unaware of histology. Diagnosis of malignancy was evaluated by using a receiver operating characteristic (ROC) analysis, also overall accuracy, average sensitivity, specificity and negative and positive predictive values were calculated. Interobserver agreement was defined by the Kappa statistics. Histologic examination revealed 29 malignant [hepatocellular carcinoma (HCC), n=11; cholangiocellular carcinoma (CCC), n=1; lymphoma, n=1; metastases, n=16)] and 7 benign [hemangioma, n=1; focal nodular hyperplasia (FNH), n=4, adenoma, n=2)] lesions. Six benign lesions (hemangioma n=1; FNH n=5) were proved by long-term follow-up. ROC analysis regarding the diagnosis of malignancy showed values from 0.43 to 0.62 (mean 0.57) before and from 0.70 to 0.80 (mean 0.75) after contrast agent, respectively. The average values for sensitivity, specificity, accuracy and negative and positive predictive values were 66, 26, 62, 45 and 73% unenhanced and 83, 49, 73, 65 and 82% after contrast, respectively. The interobserver agreement was 0.54 and 0.65 for unenhanced and enhanced examinations, respectively. Quantitative dynamic contrast-enhanced sonography improves the diagnosis of malignancy in liver lesions.

Microsurgical training course for clinicians and scientists at a German University hospital: a 10-year experience.

Microsurgical techniques are being increasingly applied in almost all surgical disciplines. However, the opportunities to learn these skills in a structured course are rare. We have conducted a 5-day microsurgical training course on a yearly basis since 1991. The course follows step-by-step training, starting with nonvital models for vascular and nerval microanastomoses. As the participants improve, exercises on laboratory animals are offered to close the gap between nonliving models and the clinical situation. Lectures provide theoretical and clinical background information. Clinical and experimental applications can be witnessed and practiced in a second part of the course. With this step-by-step curriculum, we conduct a successful training program, e.g., each participant is able to perform microvascular and nerval anastomoses on a reproducible basis. The organization, program, and execution of the training course are presented, together with an evaluation of the course concept by the participants concerning expectations, learning success, and level of satisfaction.

Impact of hepatic rearterialization on reperfusion injury and outcome after mouse liver transplantation.

BACKGROUND: Nonarterialized mouse liver transplantation is a well-established model for immunologic studies on rejection and tolerance mechanisms. However, the importance of graft arterialization has-in contrast to rat liver transplantation-not been thoroughly examined in the mouse model. The aim of the current study was to investigate the impact of arterial reconstruction on long-term graft survival, histologic alterations, ischemic liver damage, and early immunologic activation pathways. METHODS AND RESULTS: All recipients of arterialized (n=6) and nonarterialized (n=8) syngeneic liver grafts survived indefinitely. There were no differences in their histologic architecture, including no evidence of bile duct proliferation, periductal fibrosis, or alterations in serum transaminases, in long-term survivors from either group. Twenty-four hours after syngeneic liver transplantation, aspartate aminotransferase and alanine aminotransferase levels were increased to an equivalent extent in both groups, in agreement with early reperfusion injury and solitary traumatic injuries as assessed histologically (n=3 per group). Visualized by immunohistochemistry, intercellular adhesion molecule-1 expression was increased on sinusoidal and hepatic vein endothelium at both 1 and 100 days after transplantation, in both arterialized and nonarterialized grafts. Messenger RNA for interleukin-1, interferon-gamma, and tumor necrosis factor-alpha were measured by real-time polymerase chain reaction 24 hr after transplantation. No significant changes in the expression of cytokine mRNA levels were observed. CONCLUSIONS: Arterialization of mouse liver grafts does not appear to have a major impact on survival rate or the degree of immunologic activation. Therefore, the value of arterial reconstruction in mouse liver transplantation for experimental investigations is negligible.

Prolongation of small bowel allograft survival with a sequential therapy consisting of a synthetic MHC class II peptide and temporarily low-dose cyclosporine A.

It has been extensively documented the role of the indirect pathway of allorecognition in allograft rejection. However, recent data demonstrate that the manipulation of this pathway could be also sufficient to promote prolongation of allograft survival. In the present study we evaluated the effect of preoperative immunization with the WF-specific MHC class II peptides RT1.D2 and RT1.B2 in combination with low-dose CsA from days 0 to 7 (5 mg/kg/day) and from days 8 to 30 (1 mg/kg/day) after WF small bowel transplantation. Seven days before and on the day of transplantation, LEW recipients were immunized with the two WF MHC class II peptides RT1.B2 and RT1.D2. The CsA monotherapy induced an allograft survival of 49.3 +/- 6.1 days. MHC class II peptide immunization had a limited effect on allograft survival for RT1.D2 (47.1 +/- 3.8 days) and induced prolongation of allograft survival for RT1.B2 (73.6 +/- 34.6 days). This effect seems to be based on the absence or silence of RT1.B2-reactive T cells and rejection seems to be correlated with the presence of RT1.B2-specific T cells in the late phase. Therefore, the combination of RT1.B2 with low-dose CsA shifts the immunological response and protects small bowel allograft rejection.

Application of Molecular Adsorbent Recirculating System in patients with severe liver failure after hepatic resection or transplantation: initial single-centre experiences.

Acute liver failure after hepatic surgery is still plaqued with high mortality rate. Recently, a liver dialysis system (MARS) that allows detoxification of albumin-bound substances and may hereby support liver regeneration and patient's recovery has been developed. In the present study, we report our experiences with MARS dialysis in patients with liver failure after hepatic resection or transplantation. Between September 1999 and January 2001, five patients were treated with MARS (2-5 courses). Though beneficial effects such as improvement of encephalopathy and renal function as well as reduced bilirubin levels were recorded during MARS therapy, only one patient survived. Neither significant technical problems nor adverse effects occurred by using MARS dialysis. We conclude that in surgical patients, acute liver failure is usually part of a complicated clinical course affecting multipleorgan systems. Thus, it is difficult to determine the specific influence of MARS on patient's outcome. However, beneficial effects observed in our patients justify its continuous use and may stimulate further evaluation in controlled studies with surgical patients.

Mechanisms of tolerance induction after rat liver transplantation: intrahepatic CD4(+) T cells produce different cytokines during rejection and tolerance in response to stimulation.

Increasing evidence supports the existence of regulatory T cells that may inhibit the allogeneic immune response after transplantation by secreting regulatory cytokines. To determine whether rat liver tolerance is associated with intrahepatic regulatory T cells secreting a characteristic cytokine profile, we analyzed the cytokine production of freshly isolated intragraft CD4(+) T cells at different times postoperatively by semiquantitative reverse transcription-polymerase chain reaction and by enzyme-linked immunosorbent assay before and after in vitro stimulation. Orthotopic arterialized liver transplantation was performed in two allogeneic rat strain combinations, one with fatal acute rejection (DA-to-LEW) and one with long-lasting tolerance (LEW-to-DA) without immunosuppression despite a complete major histocompatibility complex mismatch (spontaneous liver tolerance). Liver allografts of both groups showed continuously increasing cellular infiltration between day 3 and day 7 after transplantation. In this inflammatory situation, very low levels of interleukin-13 were detectable directly after cell isolation, as well as after in vitro stimulation. However, after 30 days, intrahepatic CD4(+)T cells in the tolerance group were then able to express elevated messenger RNA levels of the anti-inflammatory cytokine interleukin-13 in response to stimulation. This result indicates the presence of an intragraft Th2-like CD4(+) T cell population, which may have a regulatory function in the induction of liver tolerance.