Murine hepatic stellate cells veto CD8 T cell activation by a CD54-dependent mechanism

The liver has a role in T cell tolerance induction, which is mainly achieved through the functions of tolerogenic hepatic antigen-presenting cells (APCs) and regulatory T cells. Hepatic stellate cells (HSCs) are known to have various immune functions, which range from immunogenic antigen presentation to the induction of T cell apoptosis. Here we report a novel role for stellate cells in vetoing the priming of naive CD8 T cells. Murine and human HSCs and stromal cells (but not hepatocytes) prevented the activation of naive T cells by dendritic cells, artificial APCs, and phorbol 12-myristate 13-acetate/ionomycin by a cell contact-dependent mechanism. The veto function for inhibiting T cell activation was directly correlated with the activation state of HSCs and was most pronounced in HSCs from fibrotic livers. Mechanistically, high expression levels of CD54 simultaneously restricted the expression of interleukin-2 (IL-2) receptor and IL-2 in T cells, and this was responsible for the inhibitory effect because exogenous IL-2 overcame the HSC veto function. CONCLUSION: Our results demonstrate a novel function of HSCs in the local skewing of immune responses in the liver through the prevention of local stimulation of naive T cells. These results not only indicate a beneficial role in hepatic fibrosis, for which increased CD54 expression on HSCs could attenuate further T cell activation, but also identify IL-2 as a key cytokine in mediating local T cell immunity to overcome hepatic tolerance.     

Studies on the oxygen radical mechanism involved in the small intestinal reperfusion damage

Characteristic mucosal lesions develop in the small intestine during ischaemia and hypotension. This tissue damage can be further aggravated in the immediate reperfusion phase, presumably secondary to the generation of oxygen free radicals which have been proposed to be generated in this situation through the hypoxanthine-xanthine oxidase system. This was further investigated in the cat small intestine using a standardized regional intestinal hypotension model in which the effects of allopurinol (a xanthine oxidase inhibitor) were compared to those of an exogenous supply of inosine. The grade of mucosal damage, the nucleotide levels, the concentrations of hypoxanthine, total and oxidized glutathione, and of conjugated dienes were measured in the intestinal tissue. The results indicate that oxygen radicals generated by xanthine oxidase are very important, but not the only significant factor in the small intestinal reperfusion damage.     

Intravenous administration of glutathione protects parenchymal and non-parenchymal liver cells against reperfusion injury following rat liver transplantation

AIM:To investigate the effects of intravenous administration of the antioxidant glutathione (GSH) on reperfusion injury following liver transplantation.METHODS:Livers of male Lewis rats were transplanted after 24 h of hypothermic preservation in University of Wisconsin solution in a syngeneic setting. During a 2-h reperfusion period either saline (controls,n=8) or GSH (50 or 100μmol/(h·kg),n=5 each) was continuously administered via the jugular vein.RESULTS:Two hours after starting reperfusion plasma ALT increased to 1 457±281U/L (mean±SE) in controls but to only 908_+187 U/L (P<0.05) in animals treated with 100μmol GSH/(h·kg).No protection was conveyed by 50μmol GSH/(h·kg).Cytoprotection was confirmed by morphological findings on electron microscopy:GSH treatment prevented detachment of sinusoidal endothelial cells (SECs) as well as loss of microvilli and mitochondrial swelling of hepatocytes. Accordingly, postischemic bile flow increased 2-fold. Intravital fluorescence microscopy revealed a nearly complete restoration of sinusoidal blood flow and a significant reduction of leukocyte adherence to sinusoids and postsinusoidal venules. Following infusion of 50μmol and 100 μmol GSH/(h·kg),plasma GSH increased to 65±7mol/L and 97±18μmol/L,but to only 20±3mol/L in untreated recipients.Furthermore, plasma glutathione disulfide (GSSG) increased to 7.5±1.0mol/L in animals treated with 100μmol/(h·kg) GSH but infusion of 50μmol GSH/(h·kg) did not raise levels of untreated controls (1.8±0.5mol/L vs 2.2±0.2mol/L).CONCLUSION:Plasma GSH levels above a critical level may act as a “sink” for ROS produced in the hepatic vasculature during reperfusion of liver grafts.Therefore, GSH can be considered a candidate antioxidant for the prevention of reperfusion injury after liver transplantation, in particular since it has a low toxicity in humans.     

Comparative analyses of bone marrow micrometastases in breast and gastric cancer

This study is a comparative analysis of the prevalence, absolute number and aggregation status of bone marrow micrometastases (BMM) between breast (n = 234) and gastric (n = 102) cancer patients based on a standardized number of 1 × 10⁶ bone marrow-derived cells per patient. Additionally, expression of the epithelial cell adhesion molecule E-cadherin was analyzed on disseminated tumor cells. A positive BMM status was demonstrated in 88/234 breast and 45/102 gastric cancer patients. The presence of CK18⁺ cells positively correlated with parameters of advanced tumor progression in breast, but not in gastric cancer. Interestingly, 25.2% of the node-negative patients already had micrometastatic cells in the bone marrow at diagnosis. Regarding the absolute number of CK18⁺ cells and the frequency of CK18⁺ cell clusters, no significant difference was found between the 2 tumor types. However, clusters consisting of more than 10 CK18⁺ cells (type II clusters) were present exclusively in breast cancer patients. Additionally, co-expression of CK18 and E-cadherin was detectable in 15/21 micrometastases-positive breast but in only 1/9 gastric cancer patients. While prevalence of micrometastatic cells in bone marrow is discussed as an early indicator for systemic disease, aggregation status and a certain antigen profile might be indicative for site-specific differences in the manifestation pattern of solid metastases. © 1996 Wiley-Liss, Inc.     

The prevention and treatment of vascular graft infection with a Triclosan (Irgasan)-bonded Dacron graft: an experimental study in the pig.

Objectives: to evaluate the role of Triclosan (Irgasan(R)) in the prevention of prosthetic graft infection. Material and methods: fifty-one pigs were assigned randomly to six groups. Group I (graft) and II (graft and Triclosan) were control groups. Groups III (graft) and IV (grafts and Triclosan) were contaminated with 2 x 10(7)CFU/ml S. aureus. Groups V (graft) and VI (graft and Triclosan) were intraoperatively contaminated with 2 x 10(7)CFU/ml S. aureus and reoperated on after 7 days. Remaining animals were sacrificed on day 28. The end point of the investigation was vascular graft infection, defined as the bacteriological and/or histological proof of infection. Results in both control groups no vascular graft infections were detected in Groups I and II. All of the group III animals presented but none of the group IV developed a graft infection (p <0.02). All of the group V animals presented and 10 of 12 animals developed a graft infection. Conclusion: in this animal model Triclosan bonding appears effective in preventing prosthetic graft infection. However, the in situ replacement of Triclosan-protected grafts was not successful in the treatment of graft infection.     

181. Beeinflusst die Ätiologie die Prognose des Multiorganversagens?

Zusammenfassung An 63 Sepsiskranken waren wichtige Ausgangsherde: Peritonitis 24, Verbrennungswunden 12, Bronchopneumonie 10, Cholangitis 5, Venenkatheter 3. Sepsisfrühzeichen: Fieber 39 °C 55, Schüttelfrost 48, Tachycardie 63, Hypotension 47, Psychosen 35, Magen-Darm-Atonie 12, Thrombocytensturz 30, Leukocytose 53, Leukopenie 12, positive Blutkultur 13, ZVD-Anstieg 33. Unter Organversagen (52 Kranke) führt Atemsuffizienz 39. 40 der 63 Kranken starben (63,5%), 2 von 11 ohne, 7 von 18 mit Mono-, 16 von 18 mit 2-Organ-, 11 von 12 mit 3-Organ-, 4 von 4 mit mehr als 3-Organ-Versagen.     

Intraoperative, endoscopic lithotripsy of pancreatic duct calculi. A contribution to the surgical treatment of chronic calcifying pancreatitis

The problem of chronical calcifying pancreatitis is demonstrated in two female patients. Resection of the pancreas is necessary, if prepapillar concrements cannot be extracted. By two new techniques, ultrasound-lithotripsy and laser-induced shock-wave-lithotripsy, it is possible to destroy concrements and to remove them. These new techniques are now used primarily in surgery.     

Different techniques of laparoscopic end-to-end small-bowel anastomoses

The aim of the study was to prove that laparoscopic stapling devices can be used to create a bowel anastomosis. Three groups with n=6 pigs each were subjected to different techniques of small-bowel anastomoses. In groups I and II anastomosing of the bowel ends was carried out with singly placed staples using a hernia stapler. (Group I: Two-thirds of the circumference became inverted and one-third everted. Group II circumferentially everted). In group III triangular everted anastomoses were produced using a linear noncutting stapler. All animals survived the observation period of 14 days and were postmortally examined. Average construction time was 59 min for groups I and III and 47 min for group II. Average diameters were 14 mm, 16 mm, and 18 mm for groups I, II, and III, respectively. There were no significant differences between the techniques concerning the stability of the anastomoses as expressed by bursting pressures. There were two stenoses in group I animals caused by electrocautery during preparation of the bowel ends prior to anastomosing. Anastomotic insufficiencies or fistulas were not observed clinically or with Gastrografin studies. We conclude that anastomoses in the pig can laparoscopically be constructed by employing singly placed staples as well as a linear stapler. Further investigations of these techniques on large bowel and human specimens are required prior to their clinical use in humans.     

Laser vaporization of leiomyoma of the esophagus

We present the case of a 67-year-old man with a stenosing leiomyoma of the esophagus, which led to dysphagia. Because of severe concomitant diseases, thoracotomy was not possible in this patient. Endoscopic laser ablation was a fast and successful treatment; more than 2 years have passed without any sign of recurrence.     

Transcranial Doppler curve analysis. On the pathophysiology of unilateral carotid stenoses

Vascular reactivity to changes in arterial CO2 content can be measured by analysis of Doppler curves in the middle cerebral artery (MCA). Vascular reactivity indicates the capability of the cerebrum of controlling peripheral resistance. In patients with threatening cerebrovascular disease (CVD) vascular autoregulation may be reduced. The circle of Willis plays a central role in the pathophysiology of unilateral high-grade ICA-stenosis. Previous classification of the degree of stenosis or of the clinical stage does not allow to describe the actual pathophysiology or prognosis of CVD sufficiently.