[Preventing venous thromboembolism]. / Prävention venöser Thromboembolien.

Routine antithrombotic prophylaxis today is consistently a part of surgical treatment. The indication and choice of both physical and medical prophylactic measures depend upon the individual thromboembolic risk profile of the patient. This is determined by expositional (procedure, trauma) and dispositional patient-related risk factors. Clinical thromboembolic risk can be differentiated into three risk categories (low, moderate, high) and determines the risk-adapted kind of prophylaxis. Unfractionated heparin and low molecular weight heparins have proven most effective in long-term medical treatment but are still limited in their use by some side effects. The development of new anticoagulant agents may improve antithrombotic prophylaxis and overcome some disadvantages of antithrombotic drugs used till now.

Regional chemotherapy in the treatment of advanced pancreatic cancer--is it relevant?

The treatment of pancreatic cancer is still problematic for physicians. Only 15% of patients present with resectable tumours, and systemic chemotherapy is of limited effectiveness. In order to achieve higher local drug concentrations in the tumour without causing the side-effects of a comparable level of systemic treatment, regional chemotherapy has been introduced as an alternative treatment. Several techniques have been developed over recent years, these include: celiac axis infusion (CAI), CAI with microspheres or haemofiltration, aortic stop flow (ASF) and isolated hypoxic perfusion (IHP). Whilst several authors have reported improved response rates and a prolongation of median survival time, these results have not been confirmed by others. In addition, the incidence of side-effects and the rate of technical complications have been reported to be high during regional chemotherapy. Except for a single trial containing 14 patients, no randomised trial comparing systemic and regional chemotherapy has been conducted. For these reasons, none of the reported treatment regimens can be considered to be standard treatment and in order to evaluate, if regional chemotherapy is indeed superior to systemic chemotherapy, randomised trials must be conducted.

Continuous regional treatment with fluoropyrimidines for metastases from colorectal carcinomas: influence of modulation with leucovorin.

Hepatic regional treatment represents an attempt to improve tumor response by increasing drug concentration with low systemic toxicities. Recently in vitro and clinical studies have shown that the cytotoxicity of 5-fluorodeoxyuridine (FUDR) and 5-fluorouracil (5FU) can be potentiated by high doses of leucovorin (LCV). Two pilot studies with intraarterial FUDR, 5FU, and LCV were initiated. Since 1982, 221 patients with colorectal liver metastases were treated by various forms of long-term monthly continuous regional treatment using implantable ports or pumps. FUDR (0.05 to 1.7 mg/kg/d) was administered alone or combined with 5-FU and leucovorin. In 61 patients curative liver resection was possible and was followed by adjuvant arterial treatment. Overall median survival time (MST) was 15 months and increased to 36 months after liver resection. This was influenced by the following important factors: treatment, number of metastases, extent of infiltration, tumor volume, and minimal intraoperatively diagnosed extrahepatic disease. The response rate varied from 69% to 23%. Time of development of extrahepatic progression was not delayed by additional systemic treatment. Local side effects significantly depended on the duration of arterial infusion. The rate of biliary sclerosis ranged from 19% to 0%. Occurrence of chemical hepatitis was between 7% and 38%. In contrast, after combined intraarterial treatment with LCV, systemic side effects, mainly stomatitis and diarrhea, were dose limiting. Despite the improvement of survival after regional treatment, further randomized trials are mandatory to compare regional with relevant systemic treatment.

Development of an ultrasensitive in vitro assay to monitor growth of primary cell cultures with reduced mitotic activity.

Primary cell cultures, such as isolated epithelial cells, neuronal cells, or hepatocytes are characterized by a very low mitotic activity. Monitoring of small changes in cell numbers requires staining with a DNA-specific dye with an extremely high sensitivity and a low inter- and intraassay variability. For this purpose, an ultrasensitive in vitro assay has been developed based on the fluorescent nucleic acid stain PicoGreen. PicoGreen has been shown to detect as little as 0.5 ng pure DNA or 10(2) cells (interassay SD < 10%, intraassay SD < 5%). This is far above the limit of sensitivity of conventional fluorochromes, such as Hoechst 33342 or propidium iodide. To obtain optimum efficacy of PicoGreen, cells were digested with papain for 20 h at 60 degrees C prior to staining. Under these conditions, the slope factor was calculated to be 0.105 relative fluorescence units (RFU)/cell, which is far superior to the slope factor of Hoechst 33342 (0.0137 RFU/cell) or propidium iodide (0.0077 RFU/cell). Analysis of the blank values revealed a very low autofluorescence of PicoGreen, which is only 1/50th of the autofluorescence of Hoechst 33342 and 1/5th of the autofluorescence of propidium iodide. Additional coating of the culture plates with extracellular matrix proteins to prevent cellular dedifferentiation did not influence the high sensitivity of PicoGreen. In conclusion, the PicoGreen-assay seems to be the method of choice when the growth capacity of primary cell cultures needs to be analyzed with high accuracy.

Effects of proinflammatory cytokines on cultivated primary human hepatocytes. Fluorometric measurement of intercellular adhesion molecule-1 and human leukocyte antigen-A, -B, -C, and -DR expression.

Expression of adhesion molecules and human leukocyte antigens on the surface of hepatocytes (HC) may play an important role in the immune reaction in different types of infectious and noninfectious hepatitis, liver graft rejection, and autoimmune liver diseases. The aim of this study was to evaluate the influence of the proinflammatory cytokines IFN-alpha, IFN-gamma, and IL-1 alpha on the expression of intercellular adhesion molecule-1 (ICAM-1) and HLA-A, -B, -C, and -DR on highly purified primary human HC in cell culture. Expression was assessed by semiquantitative measurement of HC in cell culture by means of computer-aided fluorometry after immunofluorescent labeling. Avidin-biotin-immunoperoxidase staining was applied on parallel cultures to evaluate cell purity (> 99%) and to confirm the results obtained by fluorometry. ICAM-1 was expressed constitutively on untreated HC in vitro. Stimulation of HC with IFN-gamma and IL-1 alpha for 24 hr resulted in an increase of ICAM-1 expression. Cultured HC were moderately HLA-A, -B, and -C positive, but HLA-DR negative. Stimulation of HC with 500 U/ml IFN-gamma for 72 hr resulted in an increase of HLA-A, -B, -C, and -DR expression, whereas stimulation with 10 U/ml IL-1 alpha for 72 hr had no influence. By using 5000 U/ml IFN-alpha for 72 hr, we achieved an increase of HLA-A, -B, and -C expression; effects on the other tested antigens were not significant. In contrast to endothelial cells and transformed human hepatocytic cell lines, ICAM-1 on HC was changed more intensively by IFN-gamma than by IL-1 alpha. Furthermore, the results reveal differences in HLA and ICAM-1 expression between HC in vivo and in vitro.

Mycophenolate mofetil decreases endothelial prostaglandin E2 in response to allogeneic T cells or cytokines.

BACKGROUND: Prostaglandin E2 (PGE2) is a powerful endogenous immune suppressant and interferes with various T-cell functions. However, it is not known in detail whether immunosuppressive drugs influence the PGE2-driven immune response in transplant patients. Therefore, we investigated the effect of several immunosuppressive compounds, in particular the novel drug mycophenolate mofetil (MMF), on endothelial PGE2 release. METHODS: Endothelial cells (HUVEC) were activated by either allogeneic CD4+ or CD8+ T cells, or by the cytokines interleukin-1 or gamma-interferon. Using an enzyme-linked immunosorbent assay, we analyzed PGE2 release of the activated HWEC in the presence of MMF, cyclosporine, or tacrolimus. As verapamil and mibefradil also possess immunosuppressive properties, they were included in the study as well. RESULTS: Activation of HUVEC with interleukin-1 or T cells resulted in a drastic accumulation of PGE2 in the supernatant. Cyclosporine or tacrolimus had no effect on PGE2 release. However, Ca2+ channel blockers, when applied at higher dosages, caused a significant increase in PGE2. Interestingly, MMF strongly diminished the PGE2 level in the cell culture supernatant in a concentration-dependent manner. CONCLUSION: The results demonstrate an inhibitory effect of MMF on PGE2 production, which may lower the benefits of the PGE2-triggered immune response after organ transplantation.

In vitro analysis of verapamil-induced immunosuppression: potent inhibition of T cell motility and lymphocytic transmigration through allogeneic endothelial cells.

BACKGROUND: Cyclosporine A (CsA) and tacrolimus prevent proliferation but not transendothelial migration of alloreactive lymphocytes into donor organs. As a result, serious adverse effects, such as nephrotoxicity and neurotoxicity, have been observed under CsA/tacrolimus therapy. The incorporation of new drugs with infiltration blocking properties might enhance the efficacy of the current immunosuppressive protocol, allowing lower CsA/tacrolimus dosage. Because Ca2+ plays a critical role in cell-cell interaction, the Ca2+-channel blocker verapamil might be a good cany. didate for supporting CsA/tacrolimus-based therapy. METHODS: A T-cell endothelial cell coculture model or immobilized immunoglobulin G globulin chimeras were employed to investigate how S- and R- verapamil interfere with the lymphocytic infiltration process. The expression and arrangement of membranous adhesion receptors and cytoskeletal F-actin filaments were analyzed by fluorometric method in the presence of. verapamil. RESULTS: Both verapamil enantiomers strongly inhibited lymphocyte infiltration. CD4+ and CD8+ T-cells were influenced to a similar extent with regard to horizontal locomotion (CD4+=CD8+), but to a different extent with regard to adhesion and penetration (CD4+ > CD8+). Moreover, penetration was blocked to a higher extent than was adhesion. ID50-values were 31 microM (CD4+-adhesion) and 11 microM (CD4+-penetration). Verapamil reduced P-selectin expression on endothelial cells and effectively down-regulated binding of T-cells to immobilized P-selectin immunoglobulin G globulins (ID50=4.4 microM; CD4+). A verapamil-induced reduction of intracellular F-actin in T-lymphocytes was proven to be mainly responsible for diminished cell locomotion. CONCLUSIONS: The prevention of CD4+ T-cell penetration by verapamil might argue for its use as an adjunct to CsA/tacrolimus-based immunosuppressive therapy.

Intraoperative gamma probe detection of neuroendocrine tumors.

UNLABELLED: Previous studies of the intraoperative use of a handheld gamma probe to localize metastases and primary tumors of colorectal cancer have shown improved assessment of tumor spread and changes in surgical management based on added information gained by radioimmunoguided surgery. We conducted a prospective study to determine whether intraoperative radiodetection is able to reveal microscopic and occult disease of neuroendocrine tumors [medullary thyroid carcinomas (MTCs), gastroenteropancreatic (GEP) tumors]. METHODS: After the injection of 180 MBq [111In-diethylenetriaminepentaacetic acid (DTPA)-D-Phe1]pentetreotide and/or 500 MBq 99mTc-dimercaptosuccinic acid (DMSA) (both for double-nuclide scintigraphy), preoperative somatostatin receptor imaging (12 patients with GEP tumors) and double-nuclide scintigraphy (10 patients with relapsing MTCs were performed. The results were combined with the information obtained from conventional imaging modalities (CT and sonography). Intraoperative radiodetection was performed 24 hr after administration of [111In-DTPA-D-Phe1]pentetreotide or 4 hr after the injection of 99mTc-DMSA using a handheld gamma probe. RESULTS: Intraoperative gamma counting localized 70 somatostatin receptor-positive lesions of GEP tumors, whereas preoperative receptor imaging visualized 74%, surgical palpation visualized 44% and radiological imaging modalities localized only 43%. In 10 patients with recurrent MTCs, the surgeon was successful in localizing and removing 30 tumor lesions using the gamma probe. Twenty-seven of 30 lesions demonstrated tumor involvement, whereas 3 lesions were false-positive (lymphadenitis). Double-nuclide scintigraphy revealed 67% (Octreoscan, 7 of 20; 99mTc-DMSA, 13 of 20), surgical palpation revealed 60% and conventional imaging methods (CT, sonography) revealed only 50% of all lesions detected intraoperatively by the handheld gamma probe. The smallest lesion identified by the handheld probe (not palpated by the surgeon) was a lymph node metastasis (5-mm diameter). CONCLUSION: The preliminary data show that intraoperative handheld gamma probe detection of microscopic and occult endocrine tumors is feasible and more sensitive than external scintigraphy and conventional imaging.

Cultured human biliary epithelial cells induce allogeneic lymphocyte activation in vitro: possible relevance in liver transplant rejection.

The biliary epithelium is a major target for allograft-directed immune responses during rejection crises after liver transplantation. This paper deals with in vitro studies on the immunogenetic potential of cultured biliary epithelial cells (BECs) to elicit an allogeneic cellular immune response. Therefore, BECs were cocultured with syngeneic and allogeneic lymphocytes in order to study lymphocyte activation. The respective lymphocytes [3H]thymidine incorporation was a measure for the proliferative activity. While syngeneic peripheral blood lymphocytes (PBL) never exhibited BEC-induced proliferation allogeneic PBL were significantly (P < 0.05) activated in all experiments (n = 6). In experiments with purified subpopulations CD8+ cells but not CD4+ cells proved to be activated by BECs. In time kinetics (n = 5) the maximum of the BEC-induced proliferation was on day 9 while the endothelial cell-induced proliferation was found to be 2 days earlier on day 7 after onset of the experiments (P < 0.05). BEC-induced proliferation was accompanied by induced IL-2 secretion (> 300 pg/ml) by activated lymphocytes as determined by ELISA. Stimulation of BECs with 500 U/ml interferon-gamma, 1000 U/ml interferon-alpha or blocking expression of HLA molecules on the surface membrane of BECs by monoclonal antibodies did not alter BEC-induced allogeneic lymphocyte proliferation. Monoclonal antibodies against CD8+ but not CD4+ suppressed proliferative activity of PBL and CD8+ cells by 40 and 45%, respectively. Overall, these results provide evidence that BECs may induce CD8+ lymphocyte activation in vivo and therefore might play a crucial role in triggering immune responses related to liver transplant rejection episodes.

Cytomegalovirus- and interferon-related effects on human endothelial cells. Cytomegalovirus infection reduces upregulation of HLA class II antigen expression after treatment with interferon-gamma.

Cultured human umbilical vein endothelial cells (HUVEs) were infected with human cytomegalovirus (HCMV) strain AD169. Up to 50% HUVEs proved to be positive for HCMV early nuclear antigens 24 hours after inoculation with virus. Following infection kinetics of surface expression of HLA class I and II, intercellular adhesion molecule (ICAM-1) and endothelial lymphocyte adhesion molecule (ELAM-1) on HUVEs were investigated by means of flow cytometry. A slight increase in HLA class I expression was observed, whereas expression of HLA class II (DR, DP, DQ) antigens was not induced by infection with HCMV. Furthermore, when compared with uninfected cells treated with interferon-gamma (IFN-gamma), reduced enhancement of HLA-DR expression was conspicuous in HCMV-infected cells treated with IFN-gamma. There is evidence that only a portion of HUVE is affected in its ability to upregulate HLA class II antigens. While expression of ICAM-1 was found to be enhanced between 8 and 20 hours after infection with a maximum at 12 hours after infection, no modulation of ELAM-1 was seen.

Lymphocytes induce enhanced expression of HLA class I antigens on cytomegalovirus-infected syngeneic human endothelial cells.

Human cytomegalovirus (HCMV) infection has been associated with enhanced expression of HLA antigens on the endothelium and with cellular infiltrates within the graft following human organ transplantation. We investigated the interactions between human cytomegalovirus-infected cultured endothelial cells and cocultured syngeneic as well as allogeneic lymphocytes. Our objective was to find out whether cocultured lymphocytes elicit HCMV-mediated immune responses. In this report we focus on the modified expression of HLA antigens on the surface membrane of human umbilical vein endothelial cells (HUVECs). Endothelial expression of HLA class I and II antigens was measured by means of flow cytometry. Cocultures of HCMV-infected HUVECs with unprimed autologous PBLs led to virus-specific lymphocyte response, resulting in enhanced expression of HLA class I on HUVECs. This effect was only observed when lymphocytes were added to HUVECs during the very early phase after virus inoculation and was due to the stimulation of the CD8+ T-cell subpopulation. The modification of endothelial HLA expression was not observed in transwell cocultures, indicating the importance of cellular contact between endothelial cells and lymphocytes to elicit this effect. We conclude that HCMV-infected endothelial cells may induce virus-specific responses of unprimed syngeneic lymphocytes that lead to upregulated HLA class I expression on the endothelium. This pathway might be of important relevance for graft rejection crises after transplantation.

Modulation of adhesion molecule expression on endothelial cells by verapamil and other Ca++ channel blockers.

Cytokine-induced expression of adhesion molecules on leukocytes and endothelial cells (EC) is a crucial point in the process of organ transplant rejection. It has been shown that protein kinase C (PKC) is involved in this activation process. Verapamil and other calcium channel blockers seem to possess immunosuppressive qualities in vivo and in vitro; some authors suggested that this is due to PKC- or calmodulin-antagonism. Thus our objectives were to further investigate the second-messenger systems involved in the stimulation of EC and to analyze whether the beneficial influence of calcium channel blockers on the outcome of transplantation is due to impaired expression of adhesion molecules on EC. Our results, obtained in an in vitro model using human umbilical vein EC, show that IL-1-induced expression of intercellular adhesion molecule-1 (ICAM-1) is in part mediated by PKC and that parallel activation of calmodulin is required. Expression of ICAM-1 was reduced to 38.5% by PKC-inhibitor H7 and to 77.2% by calmodulin-inhibitor W7. In addition, data on the intracellular events in TNF-alpha-induced expression of vascular cell adhesion molecule-1 (VCAM-1) is presented, showing that both PKC and, to a higher extent, calmodulin, are involved in this process. Expression of VCAM-1 was reduced to 63.7% by H7 and to 27.7% by W7. IL-1-induced expression of endothelial leukocyte adhesion molecule-1 (ELAM-1) is PKC-dependent but insensitive to blocking of calmodulin. Though activation of adhesion molecule expression utilizes PKC and/or calmodulin as second-messenger pathways the investigated calcium channel blockers verapamil (R- and S-enantiomers), diltiazem and Ro 40-5967 failed to inhibit adhesion molecule expression. Surprisingly, higher concentrations of verapamil (> 12.5 micrograms/ml) or Ro 40-5967 (5 micrograms/ml) significantly enhanced IL-1-induced expression of ELAM-1. ICAM-1-expression was also enhanced by verapamil, but not by Ro 40-5967 or diltiazem. This enhancement was only seen if verapamil was added maximally one hour after the cytokine stimulus indicating that transcriptional modulation is responsible for the observed effects. Our findings indicate that calcium channel blockers have an immunomodulating effect independent of adhesion molecule expression.

Oxygen radical generation by emigrated, intra-abdominal, and circulating PMNLs during human secondary peritonitis.

The purpose of the study was to characterize oxygen radical generation by emigrated, intraabdominal and circulating polymorphonuclear leukocytes (ePMNLs and cPMNLs) during peritonitis, as well as to assess any differences between oxygen radical production in patients with low Mannheim peritonitis index (MPI < 26, group 1) or high Mannheim peritonitis index (MPI > or = 26, group 2). Lucigenin-enhanced chemiluminescence was used to determine spontaneous and stimulated (FMLP, PMA, and A23 187) oxygen radical generation by ePMNLs and cPMNLs. In group 1 spontaneous and stimulated oxygen radical generation by emigrated PMNLs was markedly enhanced compared to circulating PMNLs (e.g., spontaneous oxygen radical generation: 30.3 +/- 11.8 cpm/cPMNLs versus 107 +/- 46 cpm/ePMNLs, P < 0.05) . In group 2 oxygen radical generation by cPMNLs markedly increased within 48 h after diagnosis of peritonitis and surgery, contrary to radical generation by ePMNLs (e.g., A23 187-stimulated oxygen radical generation 993.7 +/- 350 cpm/cPMNLs versus 285.6 +/- 77 cpm/ePMNLs, P < 0.05. In conclusion, cPMNLs and ePMNLs exhibit marked polymorphism in their capacity to generate oxygen radicals in response to secondary peritonitis. Severe peritonitis (MPI - 26) was associated with a strong increase in oxygen radical generation by cPMNLs without a parallel activity being manifest by ePMNLs.

In vitro inhibition of human cytomegalovirus replication in human foreskin fibroblasts and endothelial cells by ascorbic acid 2-phosphate.

Antiviral activity of L-ascorbic acid-2-phosphate (ASC-2P), a long-acting derivative of L-ascorbic acid, against several human cytomegalovirus (CMV) strains was examined in cultures of human foreskin fibroblasts (HFF) and endothelial cells (EC). ASC-2P at concentrations ranging from 0.2 to 2 mM had no effect on the number of cells expressing 72 kDa CMV immediate early antigen (IEA) while it inhibited expression of 68 kDa late antigen (LA) in infected cultures of both cell types (30% and 55% reduction for EC and HFF, respectively). In HFF cells, virus yield was reduced up to 4-fold, when ASC-2P was added after CMV infection. Antiviral effects were significantly increased in cultures pretreated with ASC-2P. In HFF and EC pretreated for three subcultures (18 days) with 0.2 mM ASC-2P, a significant reduction of cells expressing IEA (75% and 80% reduction in EC and HFF, respectively) and LA (92% and 90% reduction for EC and HFF, respectively) was observed. Pretreatment for three subcultures with ASC-2P inhibited virus yield 50- to 100-fold in EC and 100- to 1000-fold in HFF. The continuous presence of ASC-2P was not required for its antiviral activity. A significantly higher reduction of virus replication with ganciclovir and foscarnet was obtained in ASC-2P pretreated cells than in untreated controls. The results showed that ASC-2P provides L-ascorbic acid with long-lasting antiviral activity against CMV. ASC-2P may be of benefit for the adjunctive treatment of CMV infection.

Evidence of survival benefit of extended (D2) lymphadenectomy in western patients with gastric cancer based on a new concept: a prospective long-term follow-up study.

BACKGROUND: The use of extended (D2) lymph node dissection in gastric cancer achieves better locoregional tumor control than limited (D1) lymphadenectomy, but its influence on survival is controversial. The value of D2 resection is unproven in randomized trials. However, a survival benefit in favor of D2 resection has been shown in reports from some specialized centers. This study was undertaken to assess whether D2 resection improves survival. We evaluated the efficacy of D2 resection on the basis of a new concept that eliminates the stage migration phenomenon. METHODS: D2 resection achieved with a standardized technique in this prospective study included dissection of the perigastric lymph nodes (stations 1 through 6, D1 resection), as well as those at the celiac axis (stations 7 through 11) and at hepatoduodenal ligament (station 12, N2 level). We evaluated survival data of patients with involved nodes at stations 7 through 12 (N2 disease) because these nodes are left behind in a D1 resection. RESULTS: D2 resection resulted in a resection of cure in 31 patients with N2 disease, a 25% (31 of 125) increase of the curative resection compared with a supposed D1 resection. The 5-year survival rate for N2 patients was 17%, which demonstrates the therapeutic benefit of the D2 resection. In patients with pN0 and pN1 disease, the 5-year survival rates were 71% and 53%, respectively. Overall hospital mortality and morbidity were 1.3% (2 of 146) and 33.4% (40 of 146), respectively. CONCLUSIONS: D2 resection can be performed safely and is of therapeutic value in patients with advanced lymph node metastases. Furthermore, the survival data suggest indirectly a possible beneficial effect for patients with node-negative disease (N0) or early node metastases (N1).

Effects of desferrioxamine on human cytomegalovirus replication and expression of HLA antigens and adhesion molecules in human vascular endothelial cells.

Desferrioxamine (DFO), commonly used in therapy as a chelator of ferric ion in disorders of iron overload, is a potent inhibitor of human cytomegalovirus (HCMV) replication in cultured fibroblast cells. Moreover, DFO has immunomodulatory activity both in vitro and in vivo. We studied DFO effects on HCMV replication in cultured human endothelial cells and on the expression of several cell surface molecules, which mediate interactions of endothelial cells with other cell types in the immune system. The concentrations of DFO required for 50% reduction in the number of endothelial cells expressing HCMV late antigen, ranged for several HCMV strains from 5.2 to 8.8 microM. DFO concentrations ranging from 5 to 40 microM inhibited cellular DNA synthesis in a dose-dependent manner without any significant effects on the cell viability. DFO at 10 microM concentration suppressed expression of intercellular adhesion molecule-1 (ICAM-1) and endothelial leucocyte adhesion molecule-1 (ELAM-1), while it had no significant effect on the expression of vascular cell adhesion molecule-1 (VCAM-1). Expression of HLA class I and class II was not influenced by DFO treatment. The results showed that DFO is both effective in inhibition of HCMV replication and expression of ICAM-1 and ELAM-1 in endothelial cells, a combination that warrants attention to its potential use to prevent HCMV-induced allograft rejection in transplant recipients.

Inhibition of endothelial receptor expression and of T-cell ligand activity by mycophenolate mofetil.

The novel immunosuppressive drug mycophenolate mofetil (CellCept, MMF) blocks DNA-synthesis by the inhibition of the enzyme inosine monophosphate dehydrogenase (IMDH). IMDH is also involved in the synthesis of adhesion receptors which are known to play an important role in the regulation of cell-cell contacts. Therefore, application of MMF might lead to a reduction of cellular infiltrates in the course of transplant rejection. To evaluate the therapeutic value of MMF, we investigated to what extent MMF blocks T-lymphocyte infiltration in vitro with regard to (a) adhesion to endothelial cells, (b) horizontal migration along these cells and (c) penetration through the endothelial cells. The results demonstrated a strong inhibition of both CD4+ and CD8+ T-cell adhesion and penetration by MMF. The ID50 value for CD4+ T-cell adhesion was calculated to be 0.03 microM and the ID50 value for CD4+ T-cell penetration 1.21 microM. MMF did not significantly influence the horizontal migration of T-lymphocytes along the human vascular endothelial cell (HUVEC) borders. FACS-analysis revealed a diminished E-selectin and P-selectin expression on endothelial cell membranes in the presence of MMF. Although MMF did not interfere with the synthesis of T-cell adhesion ligands, the binding activity of lymphocytic leucocyte function associated antigen 1 (LFA-1), very late antigen 4 (VLA-4) and PSGL-1 (P-selectin glycoprotein ligand 1) to immobilized intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and P-selectin was impaired. Moreover, MMF prevented VLA-4 and PSGL-1 receptor accumulation on the membranes of T-cell pseudopodia. It can be concluded that MMF possesses potent infiltration blocking properties. MMF evoked down-regulation of specific endothelial membrane molecules and the loss of protein localization in the lymphocyte protrusions might be predominantly responsible for the observed blockade of cell adhesion and penetration.

Adenocarcinoma of the gastric antrum: does D2 total gastrectomy with splenectomy improve prognosis compared to D1 subtotal gastrectomy? A long-term survival analysis with emphasis on Lauren classification.

AIMS: The purpose of this retrospective study was to evaluate whether a more radical resection, including total gastrectomy (TG), D2 lymphadenectomy and splenectomy, or subtotal gastrectomy (SG), improves the prognosis of patients with an adenocarcinoma located on the distal third of the stomach. PATIENTS AND METHODS: Seventy-four consecutive patients with an antral carcinoma underwent gastric resection. Forty-three had a TG and 31 an SG. D2 lymph node dissection was carried out in 70% of all patients (30/43) and 100% (21/21) of patients with curative resection in the TG group, whereas in the SG group the patients had only a standard D1 lymph node dissection. Splenectomy was carried out in 84% (36/43) of patients in the TG group, whereas in the SG group the spleen was preserved in all patients. Follow-up was complete for 100% of the patients, with a median follow-up time of 74 months. MAIN END-POINTS OF INTEREST: Overall survival rates, mortality and morbidity rates. RESULTS: The postoperative 30-day mortality rate was 7% in the TG group and 3.2% in the SG group. The overall morbidity rate was increased from 19% after SG to 37% after TG. There was no microscopic evidence of involvement of proximal resection margins in any of 31 subtotal resected gastric specimens. Lymph node metastases to the splenic hilus (no. 10 nodes) or along the splenic artery (no. 11 nodes) were not found in any of 36 patients who underwent splenectomy and lymphadenectomy. The 5- or 10-year survival rates did not differ significantly between both groups. Analysis of survival showed no significant difference between the TG and SG groups when related to subgroups of patients with curative resection (UICC-RO resection), nodal status (pN), tumour depth (pT-category), tumour stage (pTNM), or Lauren classification (intestinal or diffuse type of carcinoma). The survival rates for patients with curative resection after 5 or 10 years were 58% in the TG group and 66% or 51% in SG group, respectively (P = 0.66). CONCLUSION: Since D2 total gastrectomy carried an increased overall morbidity risk and did not improve survival in patients with intestinal or diffuse type carcinoma, it seems that with regard to luminal gastric resection, SG is the treatment of choice for carcinomas located in the distal third of the stomach. Whether extensive radical D2 lymphadenectomy should be routinely performed in addition to SG is still controversial.The spleen should be preserved in most cases.

Primary gastric lymphomas: a clinicopathologic study with literature review.

Prognostic factors and treatment results were analysed in 28 consecutive patients with primary gastric lymphoma (PGL) diagnosed and treated, all by surgery and in many cases with additional chemotherapy (CT) and/or radiotherapy (RT), between 1977 and 1988. There were 13 patients in stage IE, 5 in IIE, and 10 in stage IV. The resection rate was 96.4% (27/28). Sixteen patients underwent an extended total and 11 a subtotal gastrectomy. Seventeen out of 25 cases (68%) were diagnosed by endoscopic biopsies. In 10 endoscopically diagnosed PGL cases the clinical staging and separation between stages IE and IIE from stage IV, due to ultrasonographic scan, computed tomography and bone marrow biopsy, was correct and the same with the surgical-pathological staging information. According to the Kiel-classification 18 patients had a low-grade and 9 patients a high-grade lymphoma. One patient could not be classified. All patients were completely followed-up, in an average time of 52 months. The probability of overall 5-year survival was 92% in stage IE, 75% in stage IIE, 88% in stages IE+IIE together, and 35% in stage IV. Extent of surgery (total vs. subtotal gastrectomy), Kiel-classification (low-grade vs. high-grade malignant histologic subtypes) and adjuvant CT in patients with stage IE (all 11 patients without CT remain in complete remission after an average of 45 months) did not significantly influence survival. The sole prognostic factor with proven impact on survival was the stage of disease (IE+IIE vs. IV: P = 0.001). For the Kiel-classification in particular there was no significant difference between low-grade and high-grade lymphomas with regard to the sex, symptomatic, extent of surgery, and stage at operation. These findings, together with data from the literature, suggest that gastric resection seems to be the optimal primary treatment in clinically assessed stages IE or IIE. In patients with stage IE disease, surgical resection can result in a cure, with no need for further therapy. The CT and/or RT can be effective in unresected and even bulky cases. Because of the difference in primary treatment, a preoperative clinical staging and separation between early stages from stage IV is always indicated.

Isolated hypoxic perfusion with mitomycin C in patients with advanced pancreatic cancer.

AIMS: Chemotherapy as a palliative therapy option for patients with advanced pancreatic cancer remains disappointing. Some authors have recently claimed high response rates and a prolongation of median survival after regional chemotherapy. Isolated perfusion may result in the highest drug concentrations within the target tissue without causing systemic side-effects. An established, commercially available system of isolated hypoxic perfusion (IHP) was therefore evaluated in patients with unresectable or recurrent pancreatic cancer. PATIENTS AND METHODS: IHP was performed in 17 patients with unresectable pancreatic cancer. Five women and 12 men with a median age of 61 years were treated. A 20-min isolated hypoxic perfusion was performed after 40 mg of mitomycin C (MMC) had been instilled into the running perfusion system over 5 min. Tumour response was evaluated by CT-scan 6 weeks after IHP. RESULTS: Twenty perfusions were carried out in 17 patients. Within 10 min of perfusion, the perfusate's PO2 decreased to 13% of the baseline value. Five minutes after the infusion of MMC a local concentration of 15.2 mg/litre was observed. Toxicity-related deaths did not occur. Nausea and vomiting (NCI> or =II: 12 episodes) were the most frequently observed toxicities after IHP. In five patients (29%) a deep vein thrombosis occurred. None of the treated patients responded to the regimen used in this trial. The median survival time after IHP was 4.2 months (range 1.3-21). CONCLUSIONS: The overall rate of side-effects and complications after IHP was high. In spite of some hopeful reports on this treatment in recent years, IHP did not show any benefit in terms of tumour response or median survival. On the basis of these experiences, this procedure should no longer be used as treatment for patients with unresectable or recurrent pancreatic cancer.