Islets of Langerhans are protected from inflammatory cell recruitment during reperfusion of rat pancreas grafts.

BACKGROUND: Ischemia/reperfusion (I/R) injury plays a pivotal role in the development of graft pancreatitis, with ischemia time representing one of its crucial factors. However, it is unclear, whether exocrine and endocrine tissue experience similar inflammatory responses during pancreas transplantation (PTx). This study evaluated inflammatory susceptibilities of islets of Langerhans (ILH) and exocrine tissue after different preservation periods during early reperfusion. METHODS: PTx was performed in rats following 2 h (2h-I) or 18 h (18h-I) preservation. Leukocyte-endothelial cell interactions (LEI) were analyzed in venules of acinar tissue and ILH in vivo over 2 h reperfusion. Nontransplanted animals served as controls. Tissue samples were analyzed by histomorphometry. RESULTS: In exocrine venules leukocyte rolling predominated in the 2h-I group. In the 18h-I group, additionally, high numbers of adherent leukocytes were found. Histology revealed significant edema formation and leukocyte extravasation in the 18h-I group. Notably, LEI in postcapillary venules of ILH were significantly lower. Leukocyte rolling was only moderately enhanced and few leukocytes were found adherent. Histology revealed minor leukocyte extravasation. CONCLUSION: Ischemia time contributes decisively to the extent of the I/R-injury in PTx. However, ILH have a significantly lower susceptibility towards I/R, even when inflammatory reactions in adjacent exocrine tissue are evident.

Optimisation of sample pre-treatment in the HG-AAS selenium analysis.

A fast and accurate method of pre-treatment for biological materials in the hydride generation-atomic absorption spectroscopy (HG-AAS) selenium determination is described. All procedures of sample pre-treatment were performed in closed-vessels in a microwave oven. After sample decomposition using a HNO3/H2O2 mixture, the pre-reduction and a 'denitrification' step (reduction of interfering nitrogen intermediates) with amidosulfuric acid were combined. Hence, analysis time and the risk of element losses or the emergence of possible contamination are minimised.

[Chronic fistulating wound infection after Lichtenstein repair of inguinal hernia, caused by a small colony variant of Staphylococcus aureus]. / Chronisch fistelnde Wundinfektion nach Lichtensteinreparation einer Leistenhernie, verursacht durch eine Small-colony-Variante von Staphylococcus aureus.

We report a case of chronic wound infection (abscess, fistula) after a Lichtenstein repair of inguinal hernia. After surgical treatment (mesh explantation), a small-colony variant (SCV) of Staphylococcus aureus was cultured microbiologically. SCV represent subpopulations of Staphylococcus aureus which are associated with chronic infections and which respond poorly to usual treatment regimes. In this case surgery and specific antibiotic treatment with flucloxacillin and rifampicin were successful.

B cell-deficient (mu MT) mice have alterations in the cytokine microenvironment of the gut-associated lymphoid tissue (GALT) and a defect in the low dose mechanism of oral tolerance.

Peripheral immune tolerance following i.v. administration of Ag has been shown to occur in the absence of B cells. Because different mechanisms have been identified for i.v. vs low dose oral tolerance and B cells are a predominant component of the gut-associated lymphoid tissue (GALT) they may play a role in tolerance induction following oral Ag. To examine the role of B cells in oral tolerance we fed low doses of OVA or myelin oligodendrocyte glycoprotein to B cell-deficient ( microMT) and wild-type C57BL/6 mice. Results showed that the GALT of naive wild-type and microMT mice was characterized by major differences in the cytokine microenvironment. Feeding low doses of 0.5 mg OVA or 250 microg myelin oligodendrocyte glycoprotein resulted in up-regulation of IL-4, IL-10, and TGF-beta in the GALT of wild-type but not microMT mice. Upon stimulation of popliteal node cells, in vitro induction of regulatory cytokines TGF-beta and IL-10 was observed in wild-type but not microMT mice. Greater protection against experimental autoimmune encephalomyelitis was found in wild-type mice. Oral tolerance in microMT and wild-type mice was found to proceed by different mechanisms. Anergy was observed from 0.5 mg to 250 ng in microMT mice but not in wild-type mice. Increased Ag was detected in the lymph of microMT mice. No cytokine-mediated suppression was found following lower doses from 100 ng to 500 pg in either group. These results demonstrate the importance of the B cell for the induction of cytokine-mediated suppression associated with low doses of Ag.

[Diagnosis of acute appendicitis. Is physical examination enough to reach a surgical decision?]. / Diagnostik der akuten Appendizitis. Reicht die körperliche Untersuchung zur OP-Entscheidung aus?

In the large majority of cases, acute appendicitis can be diagnosed on the basis of the medical history and the patient's symptoms. Urine should be drawn from every patient for urinstix and bacteriological testing, as well as blood for a blood count, electrolytes and coagulation parameters. A US should be performed, in particular to exclude possible other diagnoses. Women should be examined by a gynecologist. Once the diagnosis has been established, the patient must be sent for surgery without delay. Should there be reason for doubt, further diagnostic measures (in particular CT) should be carried out as permitted by the urgency of the case. In life-threatening situations, laparoscopy should be done immediately, and preparations made for laparotomy should this be necessary. If the symptoms are such that a wait-and-see attitude is justified, continued observation and follow-up examinations are recommended. The diagnosis of acute appendicitis can be difficult, and every patient who rouses relevant suspicion, should be seen by a surgeon.

Autoantigen-responsive T cell clones demonstrate unfocused TCR cross-reactivity toward multiple related ligands: implications for autoimmunity.

It has been suggested that the cross-reaction of a single T cell receptor with multiple different peptide ligands is a mechanism for maintaining a diverse yet compact immune repertoire. In the context of autoimmune disease it is important to understand how this property is balanced against the maintenance of self-tolerance. Specifically, whether the cross-reactivity inherent in the immune system is focused or unfocused will have important consequences for the development of autoimmune disease. If cross-reactivity is "focused," then in an immune response to a foreign antigen all T cell receptors that recognize the foreign antigen will cross-react with a specific autoantigenic peptide. However, if cross-reactivity is "unfocused," an immune response to a foreign antigen will result in the activation of a small number of self-reactive cells within a larger pool of cells specific for the foreign antigen. We have tested whether cross-reactivity is focused or unfocused by generating a panel of T cell clones that respond to two closely related ligands. W144 is an autoantigenic peptide of myelin proteolipid protein, PLP 139-151 (HSLGKWLGHPDKF), and Q144 is an altered peptide of PLP 139-151 bearing a glutamine for tryptophan substitution at position 144. The Q144-responsive clones have a broad degree of cross-reactivity with other position 144 substituted peptides. We find that despite their characteristic responses to Q144 and W144, the patterns of responses of these clones to other structurally related ligands are random, demonstrating that cross-reactivity is unfocused in the absence of selection. Maintaining a diverse range of cross-reactive interactions may limit nonspecific responses to autoantigens.

Fulminant spontaneous autoimmunity of the central nervous system in mice transgenic for the myelin proteolipid protein-specific T cell receptor.

Proteolipid protein (PLP)-139-151 is the dominant encephalitogenic peptide that induces experimental autoimmune encephalomyelitis (EAE) in SJL (H-2(s)) mice. To examine the contribution of T cell receptor (TCR) specificity in the induction of EAE, we generated transgenic mice expressing the rearranged TCR genes from an encephalitogenic or a nonencephalitogenic PLP-139-151/I-A(s)-specific T cell clone. Both types of transgenic lines developed spontaneous EAE, but, remarkably, the lines expressing the TCR from the nonencephalitogenic clone showed increasingly higher frequencies of disease (60-83%) in progressive SJL backcrosses and could not be propagated on the susceptible background. The T cells from the transgenic mice were not tolerized, because they responded vigorously to the antigen in vitro and mediated EAE when the mice were immunized with antigen. Besides being the only description of a TCR transgenic mice for the PLP-139-151/I-A(s) epitope, the results demonstrate that the TCR from a nonencephalitogenic PLP-specific T cell clone can induce autoimmune disease when expressed appropriately in vivo.

Persistent wound infection after herniotomy associated with small-colony variants of Staphylococcus aureus.

A small-colony variant (SCV) of Staphylococcus aureus was cultured from a patient with a persistent wound infection (abscess and fistula) 13 months after herniotomy. The strain was nonhemolytic, nonpigmented and grew only anaerobically on Schaedler agar. As it was coagulase-negative, it was initially misidentified as a coagulase-negative Staphylococcus. In further analysis, however, the microorganism was shown to be an auxotroph that reverted to normal growth and morphology in the presence of menadione and hemin (Schaedler agar) and could be identified as a SCV of Staphylococcus aureus. Surgery and antibiotic treatment of the patient with flucloxacillin and rifampicin for 4 weeks resulted in healing of the chronic wound infection.

Emergency laparoscopy for abdominal stab wounds.

BACKGROUND: Management strategies for abdominal stab wounds (ASW) in initially asymptomatic patients range from mandatory explorative laparotomy (EL) to conservative approaches with observation alone. Emergency diagnostic laparoscopy (DL) may play a potential role between these two extremes-hence lowering the rate of unnecessary laparotomies and keeping the rate of missed injuries to a minimum. PATIENTS AND METHODS: At our institution mandatory EL was carried out in every patient with ASW until 1992. In a retrospective study the charts of 43 patients with ASW were reviewed in terms of initial diagnostic procedures, intraabdominal injuries, and course and length of hospital stay. Between 5/1993 and 4/1995 DL was performed in a prospective study in 15 patients with suspected peritoneal penetration (PP) after ASW according to a standardized diagnostic and therapeutic algorithm. RESULTS: In 17 patients (40%) EL showed no PP; 15 (35%) had significant intraabdominal injuries, while 11 patients with PP didn't have lacerations of intraabdominal organs, resulting in an overall rate of nontherapeutic laparotomy of 65%. Mortality was 6% (n = 3), average hospital stay 8 days. Primary DL could exclude PP in 10 out of 15 patients (66%). The remaining five patients (33%) showed PP: In two patients with ASW to the right upper quadrant, intraabdominal injuries could be excluded by DL, and in one patient a low-grade liver injury was treated laparoscopically, thus avoiding laparotomy in a total of 87% (n = 13). In two patients with PP laparoscopy was converted to laparotomy: no pathological finding in one case, splenectomy for spleen laceration in the second patient, resulting in a rate of nontherapeutic laparotomies of 7%. All patients in this series had an uneventful course; average hospital stay was 2.4 days. CONCLUSIONS: DL offers an important diagnostic tool in excluding peritoneal penetration in ASW, hence lowering the rate of unnecessary laparotomies. Given experience and skills, laparoscopy may be used therapeutically in selected cases of ASW.

Heteroclitic proliferative responses and changes in cytokine profile induced by altered peptides: implications for autoimmunity.

Productive engagement of T cell receptors (TCRs) by cognate ligand (major histocompatibility complex plus peptide) leads to proliferation, differentiation, and the elaboration of effector functions. Altered peptides generated by single amino acid substitutions in the antigenic peptide have diverse effects on the outcome of the T cell response. We have generated an altered peptide (Q144) from an autoantigenic peptide of myelin proteolipid protein 139-151 by a single amino acid substitution (from tryptophan to glutamine) in the primary TCR contact at position 144 that is capable of inducing CD4(+) T cell responses in H-2(s) mice. By using a Q144-specific T cell clone (Q1.1B6), we see a hierarchy in T cell proliferation and cytokine production with various position 144 substituted peptides and have identified a peptide (L144) that hyperstimulates this T cell clone. In contrast to Q144, L144 induces maximal proliferation at 7 logs lower antigen concentration, induces greater cell death at higher antigen dose, and induces the secretion of cytokines not detected following stimulation with the cognate ligand. This heteroclitic T cell response associated with changes in cytokine profile was observed with several other T cell clones of different specificities. The L144 peptide also induces costimulation independent proliferation and cytokine production from the Q1.1B6 T cell clone. We describe this as a superagonist response. Such responses may have a role in the initiation of autoimmunity by promoting a proinflammatory environment following ligation of a cross-reactive TCR on autoreactive T cells.

[Effect of hypothermic preservation on ICAM-1 mRNA induction, leukocyte-endothelium interaction and microvascular perfusion after pancreas transplantation in the rat]. / Einfluss hypothermer Konservierung auf ICAM-1 mRNA Induktion, Leukozyten-Endothel Interaktion und mikrovaskuläre Perfusion nach Pankreastransplantation bei der Ratte.

A prolonged period of 18 h hypothermic preservation in pancreas grafts led to a significant induction of ICAM-1 mRNA, enhanced leukocyte-adherence/-extravasation and compromised microvascular perfusion upon 2 h of reperfusion when compared to a 2 h preservation period. Therefore, during the period of prolonged cold ischemia changes within the graft must take place causing a reinforced ICAM-1 mRNA-induction already early after the onset of reperfusion. These results underline the relevance of the ischemia/reperfusion injury for the development of complications arising in the early course following pancreas transplantation.

Fas- and FasL-deficient mice are resistant to induction of autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is an organ-specific autoimmune disease inducible in susceptible animals by myelin Ag-specific CD4+ Th1 cells. The mechanisms by which these cells induce inflammation and demyelination in the central nervous system (CNS) are incompletely understood. To determine the roles of Fas and FasL in the involvement of CNS autoimmune injury, we determined susceptibility to EAE of Fas-or FasL-deficient mice. Compared with wild-type mice, mice expressing lpr (Fas) and gld (FasL) mutations were relatively resistant to the development of clinical EAE, and this correlated with fewer inflammatory infiltrates and cells undergoing apoptosis in the CNS of the mutant mice. The gld and lpr mice, however, developed significant T cell responses with production of Th1 cytokines in response to the encephalitogenic myelin peptide. These results suggest that the Fas/FasL pathway plays a critical role in the development of EAE probably by mediating apoptosis within the target tissue.

[Perioperative standards for prevention of anastomotic insufficiency]. / Perioperative Standards zur Vermeidung von Anastomoseninsuffizienzen.

Anastomotic leakage is a major cause of morbidity and mortality in gastrointestinal surgery. Its incidence varies in the different segments of the GI tract being highest in the distal rectum. The rate of anastomotic leakages was reduced considerably within the last 20 years. Perioperative measures have contributed to this reduction in addition to improvements and standardization in operative technique. Perioperative nutrition, perioperative antibiotic prophylaxis and mechanical bowel preparation are widely used in colorectal surgery. Therefore they can be considered as standards. High-caloric parenteral feeding is used commonly perioperative. Its efficiency to reduce postoperative septic complications has been proven until now only for malnourished patients. The aim of perioperative antibiotic prophylaxis is to reduce the bacterial count after intraoperative contamination. Therefore tissue levels must be in the therapeutic range to cover for the expected bacteria. The efficiency to reduce postoperative wound infection has been proven, however the influence on the rate of anastomotic leakages is still controversial. Mechanical bowel preparation can reduce the bowel load but not bacterial concentration inside the bowel. Orthograde lavage with polyethylenglycol solution is feasible unless bowel obstruction is present, but its influence on anastomotic healing is still under discussion. Although all of these procedures are widely used, their influence on anastomotic healing has still to be proven by prospective, controlled trials.

[Laparoscopic versus open cholecystectomy in therapy of acute cholecystitis]. / Laparoskopische versus offene Cholezystektomie bei der Therapie der akuten Cholezystitis.

In patients with acute cholecystitis, hospital stay, blood loss, operative time and perioperative risk are compared for open and laparoscopic operations. There is a trend to wards a reduced hospital stay without any increased risk for patients with laparoscopy if critical patients are operated open.

[Management of large abdominal wall hernias with foreign implant materials (Gore-Tex patch)]. / Versorgung grosser Bauchwandbrüche durch Fremdmaterial (Gore-Tex-Patch).

OBJECTIVE: Incisional hernia repair with conventional techniques (simple closure, Mayo) is associated with high recurrence rates in the range of 30-50%. Surgical repair using different prosthetic biomaterials gains more and more acceptance. Therefore we wanted to evaluate our own results of hernia repair and analyze the results of a mesh hernioplasty using an expanded polytetrafluoroethylene patch (ePTFE). PATIENTS AND METHODS: 1. During the study period (1984-1992) a total of 205 hernia repairs (148 primary repairs, 57 repairs for recurrent hernia) were done in 173 patients at our institution using the following techniques: Mayo technique n = 90, simple one layer suture n = 56, absorbable mesh n = 25, ePTFE n = 17, other mesh techniques n = 17. In a retrospective study 135 of these patients (78%) could be examined clinically. The average follow up time was 44 months (10-105). 2. Since 1988 we used the ePTFE patch (Gore-tex Soft Tissue Patch) in selected cases for incisional hernia repair. In a second retrospective analysis the course of 26 patients, who were operated between 1988 and 1994, is reported. RESULTS: 1. Local wound complications occurred in 3-6% with conventional techniques and in 11-13% after different types of mesh repair (n.s.). Overall recurrence rates were 30% for primary hernia repair and 38% for recurrent hernia repair without statistically different rates for the various techniques. The presence of two or more patient dependent risk factors (obesity, obstructive lung disease etc.) (p < 0.05) and hernia diameter > 5 cm (p < 0.05) were identified as risk factors for hernia recurrency. 2. In the ePTFE group one patient (4%) developed a superficial wound complication, in another three patients (12%) the patch had to be removed due to deep wound infections. All three patients had revealed septic wound complications after previous surgery. The recurrence rates (17% for primary repair and 20% for repeated repair) were clearly lower compared to conventional techniques. CONCLUSIONS: The use of prosthetic mesh should be considered for repair of large or recurrent incisional hernias, especially in high risk patients (obesity, obstructive lung disease). Beside the most often used polypropylene mesh, the ePTFE patch (Gore-tex-Soft-Tissue-Patch) represents a valuable alternative in selected cases with direct contact of the prosthesis to abdominal viscera. Any previous septic wound complication or a contaminated operating field (e.g. colostomy) seems to be a contraindication for its use.

The bradykinin antagonist CP-0597 can limit the progression of postischemic pancreatitis.

Bradykinin mediates the inflammatory process of acute pancreatitis characterized by an increase of microvascular permeability, vasodilation and leukocyte activation. These phenomena are characteristic also for the ischemia/reperfusion injury of the pancreas, which in time is considered a causative factor in the pathogenesis of acute pancreatitis. The aim of this study was to investigate the influence of the bradykinin B2 receptor antagonist CP-0597. After complete ischemia/reperfusion of the pancreas in rats there is progression from postischemic acute edema to necrotizing pancreatitis over a reperfusion period of 5 days. In 8 Sprague-Dawley rats (treatment group) 18 micrograms/kg/h CP-0597 was administered intraperitoneally over 5 days with an osmotic minipump starting 15 min before release of 2 h ischemia. Animals of the placebo group (n = 8) were identically treated, but received the solvent, phosphate buffer. Animals of a control group (n = 7) underwent sham operation without ischemia. After 5 days the animals were sacrificed for histology. No morphological changes of the pancreatic gland were observed in the control group. Ischemia for 2 h resulted in necrotizing pancreatitis with high mortality (4/8 animals) during the reperfusion period of 5 days. In contrast, all animals in the treatment group survived without clinical or histological signs of necrotizing pancreatitis.

Determinants of pancreatic microcirculation in acute pancreatitis in rats.

The aim of the study was to evaluate the effects of arterial hypotension, high-volume crystalloid resuscitation, and isovolemic hemodilution on pancreatic microvascular perfusion during acute pancreatitis. Using intravital microscopy, pancreatic functional capillary density was analyzed in rats 1 and 2 hr after onset of acute pancreatitis. Pancreatic microvascular perfusion in acute pancreatitis was characterized by a (-62%) significant reduction of functional capillary density predominantly in perinecrotic but also in nonnecrotic tissue (-43%). Pancreatic microvascular perfusion failure was aggravated by arterial hypotension but attenuated by treatment with high-volume crystalloid resuscitation. Isovolemic hemodilution was found superior to high-volume crystalloid resuscitation in maintaining pancreatic functional capillary density and therefore has the best potential in preserving tissue integrity and thereby limiting progression of disease. This study underlines the importance of early fluid resuscitation/hemodilution in patients presenting with acute pancreatitis.