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Background Systemic endotoxaemia is implicated in the development of complications associated with obstructive jaundice. The aims of these studies were to assess the systemic immune response to intervention in patients with jaundice and to compare the effects of surgical and non-surgical biliary drainage on host immune function and gut barrier function. Methods In the first study, 18 jaundiced and 12 control patients were studied to assess systemic immune responses before and after intervention. In the second study, immune responses and gut barrier function were assessed following surgical and non-operative biliary decompression in 45 patients with jaundice. Results Endotoxin antibody concentrations fell significantly in patients with jaundice immediately after surgical intervention, but not after non-operative biliary drainage. This decrease was associated with a significant increase in serum P55 soluble tumour necrosis factor (sTNF) receptor concentration (5·3 versus 10·5 ng/ml; P < 0·001), urinary excretion of P55 TNF receptors (21·4 versus 78·8 ng/ml; P = 0·002) and intestinal permeability (lactulose : mannitol ratio 0·032 versus 0·082; P = 0·048). Intestinal permeability was significantly increased in patients with jaundice compared with controls (0·033 versus 0·015; P = 0·002). Conclusion These data suggest that obstructive jaundice is associated with impaired gut barrier function and activation of host immune function that is exacerbated by intervention. Surgery causes an exaggerated pathophysiological disturbance not seen with non-operative biliary drainage procedures.

Background Complex limb trauma often involves combined arterial and venous injury, and the resultant ischaemia–reperfusion injury (IRI) causes both local and remote organ injury. This study assessed the influence of the timing of restoration of venous drainage on IRI. Methods Male New Zealand white rabbits (n = 36) were randomized into six groups: sham operation (group 1) and unilateral hind limb arterial and venous occlusion for 1 h followed by no reflow for 2 h (group 2), arterial and venous reflow for 2 h (group 3), arterial reflow alone for 2 h (group 4), arterial reflow alone for 1 h followed by arterial and venous (delayed) reflow for a further 1 h (group 5), and pretreatment with an enteral combination antioxidant before occlusion of both artery and vein and delayed venous reflow (group 6). Plasma hydroperoxide (HPO) and glutathione peroxidase concentration, hind limb skeletal muscle and lung tissue wet: dry weight ratios and myeloperoxidase (MPO) concentration were measured. Results The plasma HPO level in the femoral vein effluent was significantly greater after delayed venous reflow (mean(s.e.m.) 2·02(0·54) μmol/l) than in control animals (0·98(0·10) μmol/l) (P < 0·05). There was also a significantly greater tissue wet: dry weight ratio after delayed venous reflow than in controls, in skeletal muscle (mean(s.e.m.) 6·89(0·14) versus 5·34(0·54); P < 0·05) and lung (9·20(1·14) versus 7·23(0·38); P < 0·05) tissue. Lung tissue MPO activity was significantly greater after delayed venous reflow compared with controls (3·20(0·28) versus 1·86(0·14) units/g; P < 0·005), and also in comparison to simultaneous arterial and venous reflow (2·40(0·24) units/g; P < 0·05). In the antioxidant pretreatment group there was no significant increase in plasma HPO concentration, tissue MPO level or tissue wet: dry weight ratio compared with the control group. Conclusion In combined major arterial and venous injury of the limb, delayed restoration of venous drainage leads to significantly greater local skeletal muscle injury and remote neutrophil-mediated lung injury. These results support the clinical rationale for early restoration not only of arterial inflow but also venous drainage by means of intraluminal shunts.

Objectives to investigate the effect of intestinal manipulation on intestinal permeability and endotoxaemia during elective abdominal aortic aneurysm (AAA) surgery. Design prospective randomised controlled study.Patients and methods fourteen patients undergoing elective infrarenal AAA repair were randomised into either the transperitoneal (n=7) or extraperitoneal approach (n=7). Intestinal permeability was measured preoperatively (PO), and at day 1 (D1) and day 3 (D3) after surgery using the lactulose/mannitol absorption test. Portal and systemic blood samples were taken before clamping, at completion of proximal and distal anastomoses and immediately before abdominal wound closure, for endotoxin measurement using the chromogenic limulus amoebocyte lysate assay. Results intestinal permeability was significantly increased at D1 (0.107±0.04 (mean±S.E.M.)) in the transperitoneal group compared to the PO level (0.020±0.004, p

Background Gram-negative sepsis and its sequelae frequently complicate invasive procedures in patients with obstructive jaundice. In response to endotoxin, Kupffer cells secrete tumour necrosis factor (TNF), a pivotal early mediator of sepsis. An investigation was carried out into the specific role of Kupffer cell TNF secretion following endotoxin challenge in obstructive jaundice. Methods Survival following intraperitoneal administration of endotoxin (2·0, 0·02 and 0·0002 mg per 100 g) was determined in rats following bile duct ligation (BDL) or sham operation. Plasma TNF concentration was quantified following endotoxin administration (0·0002 mg per 100 g) at 1, 2 and 6 h. Subsequently, the effect of Kupffer cell blockade by gadolinium chloride on survival and plasma TNF concentration was assessed. Results Jaundiced animals showed a significantly increased mortality rate following intraperitoneal injection of endotoxin 2·0 mg per 100 g (BDL 100 per cent versus sham 0 per cent) and 0·02 mg per 100 g (BDL 70 per cent versus sham 0 per cent; P = 0·002, Fisher's exact test). Median plasma TNF concentration was significantly greater in jaundiced animals 1 h after endotoxin administration (BDL 943 (interquartile range (i.q.r.) 211–3900) pg/ml versus sham 64 (i.q.r. 47–127) pg/ml; P = 0·002, Mann–Whitney U test). Kupffer cell blockade with gadolinium chloride increased the survival rate following endotoxin administration in BDL animals (BDL-GdCl3 100 per cent versus BDL-saline 40 per cent; P = 0·0003, Fisher's exact test) and decreased median plasma levels of TNF (BDL-GdCl3 88 (i.q.r. 0–1065) pg/ml versus BDL-saline 16 550 (1255–29 360) pg/ml; P = 0·002, Mann–Whitney U test). Conclusion Kupffer cell blockade improved survival and suppressed systemic TNF activity after endotoxin challenge. In obstructive jaundice, hypersecretion of TNF by Kupffer cells may supplement systemic cytokine production and be responsible for significant complications.

Background Sepsis and endotoxaemia occur frequently in biliary obstruction. Impaired Kupffer cell endocytosis is implicated in these events. Tumour necrosis factor and interleukin 6, secreted by Kupffer cells, are important mediators of sepsis. Kupffer cell clearance of endotoxin and secretion of cytokines in experimental obstructive jaundice were investigated. Methods Wistar rats were randomized to bile duct ligation, sham operation or control. Groups (n = 8) were studied 1 and 3 weeks after operation. Kupffer cell function was assessed using in situ hepatic perfusion. Results Clearance of endotoxin was significantly depressed 1 week (median (interquartile range) 20·3 (10·5–27·1) per cent) and 3 weeks (22·1 (20·2–23·2) per cent) after bile duct ligation compared with that in respective sham animals (35·5 (29·9–41·6) and 40·9 (37·7–47·0) per cent) and controls (39·5 (37·3–46·8) per cent). Secretion of tumour necrosis factor was significantly greater 1 week (1113·7 (706·5–1436·8) pg/ml) and 3 weeks (1118·2 (775·7–1484·1) pg/ml) following bile duct ligation compared with that in respective sham animals (114·3 (0–178·5) and 107·6 (63·7–166·4) pg/ml) and controls (0 (0–20·7) pg/ml). Interleukin 6 was not secreted by sham or control animals but was present in the perfusate from jaundiced animals at 1 and 3 weeks (52·5 (9·9–89·5) and 66·2 (60·2–193·1) pg/ml). Conclusion These data demonstrate simultaneous impairment of Kupffer cell clearance of endotoxin and increased secretion of proinflammatory cytokines in experimental obstructive jaundice. These diverse responses may contribute to the development of sepsis-related complications in biliary obstruction.

Background The endotoxin–proinflammatory cytokine cascade has been implicated in the systemic complications of severe acute pancreatitis. Although systemic proinflammatory cytokine activation has been demonstrated in experimental models, the initiating event may be pancreatic inflammation and not systemic endotoxaemia. The aim of this study was to characterise the systemic tumour necrosis factor (TNF) and interleukin-6 (IL-6) response in the taurocholate model of severe acute pancreatitis and to evaluate the role of endotoxaemia, by measuring endotoxin and antiendotoxin antibodies in the systemic compartment. Methods Acute pancreatitis was induced by the retrograde infusion of 0.2 ml 5% sodium taurocholate into the pancreas of male Wistar rats. Saline infusion was used in control rats. Animals were randomised to have venous blood sampling at 1, 2, 4, 6 or 12 h after pancreatic infusion. Blood samples were assayed for endotoxin [limulus amoebocyte lysate (LAL) assay], immunoglobulin(lg)G and IgM antiendotoxin antibodies (ELISA), TNF (WEHI bioassay and ELISA) and IL-6 (B9 bioassay). Results Plasma endotoxin was not detected and there was no difference in IgG and IgM antiendotoxin antibody concentration between pancreatitis animals and controls. At 1 and 2 h, systemic TNF was detected in rats with pancreatitis using both bioassay and ELISA, but not in controls ( p p p Conclusion Systemic proinflammatory cytokine activation occurs in the taurocholate model of severe acute panceatitis. TNF activation is biphasic, occurring at 1 and 2 h following induction of pancreatitis and again at 12 h, while systemic IL-6 concentration increased throughout the period of study. These cytokine responses may be independent of systemic endotoxaemia, since endotoxin was not detected in the systemic compartment and there was no change in the concentration of antiendotoxin antibodies.

Background It has been suggested that bowel permeability is altered following abdominal aortic aneurysm surgery. The effect of ischaemia-reperfusion injury to the lower limb on the morphological structure, neutrophil infiltration and permeability of the bowel was investigated. Methods Histological assessment of the bowel was undertaken in five groups of Wistar rats: control, 3 h of bilateral hind limb ischaemia and 3 h of bilateral hind limb ischaemia followed by 1, 2 or 3 h of reperfusion. Using an everted gut sac model and 14 C-labelled polyethylene glycol, the effect of ischaemia-reperfusion on small bowel permeability was studied. Results The small bowel showed a significant decrease in mucosal thickness, villus height and crypt depth in animals subjected to ischaemia followed by 2-hr reperfusion (mean(s.e.m.) 420(15), 217(9) and 163(6) μm respectively) compared with controls (481(11), 245(6) and 195(6) μm) (P

Objectives To assess the specific host responses to systemic endotoxemia and tumor necrosis factor (TNF) activation after abdominal aortic aneurysm surgery by measuring antiendotoxin core antibodies (EndoCab) immunoglobulin (Ig)G and IgM, and soluble p55TNF receptor concentrations. The role of the gut in initiating these immune responses was evaluated by correlating the systemic markers to changes in the intramucosal pH of the sigmoid colon. Design Retrospective, reevaluation study. Setting Vascular unit of a university hospital. Patients Eleven patients who underwent abdominal aortic aneurysm repair surgery were selected from a larger patient cohort (n = 42) on the basis of their clinical outcome (four patients had fatal complications and seven patients had an uneventful recovery). Interventions After induction of anesthesia, intramucosal pH of the sigmoid colon was measured using tonometry. Blood samples were obtained from indwelling catheters or direct venipuncture preoperatively, during surgery, and daily until postoperative day 5. Measurements and Main Results Those patients who died developed intramucosal acidosis of the sigmoid colon intraoperatively. Significant consumption of both IgG and IgM EndoCab antibodies was found in all patients. By measuring the concentration of antibodies to a neutral antigen, i.e., tetanus toxoid, the consumption of IgG EndoCab antibody concentrations was shown to be a specific host response. In all patients, reciprocal changes in the serum concentrations of p55TNF receptor and interleukin (IL)-6 were observed. The percentage increase in p55TNF receptor and the concentration of IL-6 were significantly higher in the nonsurvivor group by 48 hrs. There were significant correlations between, intramucosal pH and EndoCab antibodies, intramucosal pH and p55 TNF receptor, and p55 TNF receptor and IL-6. Conclusions The development of colonic ischemia is associated with a significant consumption of IgG EndoCab antibodies and a simultaneous increase in soluble p55TNF receptor. This study provides further support for the concept that gut-derived endotoxin and the generation of TNF may play a role in the pathogenesis of complications after abdominal aortic aneurysm surgery. (Crit Care Med 1997; 25:1472-1479)

Background Tumour necrosis factor (TNF) is a pleiotropic cytokine produced largely by macrophages and T lymphocytes. It has been implicated in the pathogenesis of numerous immunoinflammatory processes. Recently, a number of studies have indicated that anti-TNF antibodies may be of value in the treatment of inflammatory bowel disease. Method The literature is reviewed regarding the role of TNF in the pathogenesis of inflammatory bowel disease and the results of administering TNF inhibitors. Results and conclusions TNF may have a role in the pathogenesis of inflammatory bowel disease. The effects of TNF inhibitors are complex and incompletely understood. Anti-TNF antibody strategies may have a role in the treatment of acute exacerbations of the disease but are unlikely to be appropriate therapies for long-term management.

BACKGROUND: Gram negative septic events are the commonest source of morbidity and mortality as a result of surgery in jaundiced patients. The large intestine provides the major source of Gram negative bacteria in mammals and is implicated in the pathogenesis of systemic endotoxaemia in obstructive jaundice. Bile salts have an important part in maintaining indigenous microecological homeostasis through their emulsifying properties. AIMS: The aim was to investigate the effects of biliary obstruction and isolated external biliary diversion on gastro-intestinal structure and caecal bacterial flora in relation to bacterial translocation. METHOD: Six groups of adult male Wistar rats were studied (no operation, sham operated, and bile duct ligated (BDL) for one and three weeks and a choledocho-vesical fistula (CDVF) for one week). At the end of the study period plasma was assayed for evidence of endotoxaemia and the animals were tested for bacterial translocation to the mesenteric lymph node complex (MLNC), liver, lungs, and spleen. Quantitative and qualitative bacteriological studies were performed on the caecal contents and segments of colon and terminal ileum were washed and prepared for histological assessment. RESULTS: Bacterial translocation was significantly increased in the BDL1 (68.8%) and BDL3 (60%) groups compared with the sham1 (6.3%), sham3 (9.1%), No operation (0%), and CDVF1 (16.7%) groups. Although translocation was more pronounced in the BDL1 group, this was almost exclusively to the MLNC compared with the more widespread translocation to other organs in the BDL3 group. The BDL3 group was the only group with significantly raised concentrations of endotoxin and anticore glycolipid. The caecal Gram negative aerobic counts were significantly increased in the BDL1 and CDVF1 groups compared with all other groups. There was evidence of structural abnormalities in the terminal ileum of rats jaundiced for three weeks, but not in the other groups. CONCLUSIONS: Biliary obstruction for one and three weeks promotes bacterial translocation although the mechanisms may be different. Absence of intralumenal bile results in a significant but self limiting increase in the Gram negative aerobic population, which may account for translocation in the early stages of biliary obstruction. As the duration of biliary obstruction increases systemic endotoxaemia is a consistent feature which, combined with factors such as immunological depression and physical disruption of gut barrier function, may promote bacterial translocation perpetuating systemic sepsis.

The effect of low-dose dopamine administration on intramucosal pH (pHi) of the sigmoid colon and on postoperative function of various organs in patients undergoing elective abdominal aortic aneurysm repair was examined. Nineteen patients were randomized to two groups; nine received dopamine at a rate of 3 μg per kg per min for 24 h from induction of anaesthesia and ten control patients received fluids without dopamine. pHi was measured with a silicone tonometer and daily samples of blood were taken for measurement of liver transaminase activity, arterial oxygen saturation and creatinine concentration. Mean(s.e.m.) pHi fell to a significantly lower minimum value in those receiving dopamine compared with control patients (6.86(0.10) versus 7.11(0.08), P

Quantitative and qualitative disturbances in faecal flora suggest a role for enteric bacteria and their products in the pathogenesis of inflammatory bowel disease (IBD). This study investigated the hypothesis that systemically circulating endotoxins are of pathogenic significance in IBD by measuring antibody, cytokine, and acute phase protein responses. Systemic endotoxaemia was found in 88% patients with ulcerative colitis (n = 25) and 94% with Crohn's disease (n = 31) during clinical relapse. Systemic endotoxaemia correlated positively with anatomic extent and clinical activity of ulcerative colitis. Circulating tumour necrosis factor (TNF) was detected in 40% of patients with ulcerative colitis and 45% with Crohn's disease. Plasma TNF concentrations correlated with clinical and laboratory measures of disease activity and were associated with a surgical outcome to the disease episode. Plasma soluble TNF receptor p55 concentration correlated positively with disease activity and endotoxin core antibody concentrations. Plasma IgG endotoxin core antibody concentrations were significantly increased in patients with Crohn's disease and correlated with systemic endotoxaemia. The presence of systemic endotoxaemia, its correlation with disease activity, disease extent, and endotoxin core antibody concentration and the detection of circulating TNF and soluble TNF receptors all support a pathogenic role for endotoxins in IBD.

1. Infection in the neonatal period is difficult to diagnose and is a significant cause of morbidity and mortality in preterm infants. 2. We investigated prospectively the predictive value of plasma measurement of bacterial endotoxin (lipo-polysaccharide), tumour necrosis factor-α, interleukin-6, interleukin-8, intercellular adhesion molecule-1 and C-reactive protein in 60 consecutive newborn infants suspected of having neonatal infection. Plasma samples were taken at the time of acute clinical deterioration. Sixty-two cord blood samples were studied as controls taken at elective Caesarean section. 3. Forty-three infants had confirmed infections, 25 with positive blood cultures. Tumour necrosis factor-α and bacterial endotoxin levels were not significantly elevated over controls, whereas interleukin-6, interleukin-8 and intercellular adhesion molecule-1 levels were all significantly increased in the infected group compared with controls (all P < 0.001). 4. Increased plasma intercellular adhesion molecule-1 levels were a highly sensitive (88%) indicator of clinical infection and were independent of C-reactive protein. Use of these two assays in combination improved the diagnostic sensitivity to 95% and gave a negative predictive value of 97%. Addition of interleukin-6 or interleukin-8 measurements failed to further significantly enhance the prediction of infection. 5. Measurement of intercellular adhesion molecule-1 level may have a clinical role in rapidly confirming, or predicting, the likely diagnosis in cases of suspected neonatal infection.

In 30 patients undergoing elective repair of abdominal aortic aneurysm the intramucosal pH (pHi) of the sigmoid colon was measured. Blood for endotoxin assay was taken at intervals before, during and after surgery. Daily measurements were made of liver transaminase activity and of arterial partial pressure of oxygen (PaO2). The mean(s.e.m.) peak systemic endotoxin concentration in those who developed intramucosal acidosis (pHi below 7·00) was 90(14) pg/ml, compared with 42(5) pg/ml in those who did not (P < 0·01). In the 14 patients whose pHi fell below 7·00, the mean(s.e.m.) postoperative rise in aspartate transaminase activity was 346(74) per cent, compared with 181(20) per cent in those whose pHi remained above this level (P < 0·05). The mean(s.e.m.) postoperative ratio of PaO2, to the fraction of inspired oxygen was 177(11) mmHg in those with intramucosal acidosis, compared with 260(24) mmHg in those whose pHi remained above 7·00 (P < 0·01). These results demonstrate a relationship between bowel ischaemia, endotoxaemia and organ impairment following elective aneurysm repair.

Macrophage major histocompatibility complex (MHC) class II antigen expression is associated with defective antigen presentation to T lymphocytes in animals and is predictive of patient outcome after major trauma or sepsis. In this study, class II antigen (HLA-DR and DQ) expression on peripheral blood monocytes was investigated in patients with inflammatory bowel disease in relation to disease activity and outcome. The percentage positivity and fluorescent intensity of expression of HLA-DR and DQ antigens on monocytes were determined in whole blood samples using dual colour immunofluorescence labelling and flow cytometry. Disease activity was assessed using clinical and laboratory indices. There was no significant difference in percentage positivity or fluorescent intensity of class II antigen expression between patients with Crohn's disease, those with ulcerative colitis, and healthy volunteers. The percentage of monocytes displaying HLA-DR positivity was significantly decreased in patients with active ulcerative colitis (active %: 49.5 (5.6); inactive %: 78.9 (6.9); p = 0.01). Data expressed as mean (SEM). In patients requiring surgical resection of diseased bowel, the percentage of monocytes displaying HLA-DR positivity (51.9 (4.0) %) was significantly reduced compared with patients receiving medical treatment alone (81.1 (3.5) %; p < 0.001). Reduced monocyte HLA-DR expression is therefore associated with disease activity and seems to predict outcome in patients with inflammatory bowel disease.

In a cohort of victims of traumatic brain injury, 18 out of 50 patients had a plasma tumour necrosis factor (TNF) concentration above 2 pg/ml within 24 h of injury (mean 12.19, SD 45.96 pg/ml). Twenty-six had CSF samples available of which 17 demonstrated TNF concentrations above 1 pg/ml (mean 3.98, SD 3.61 pg/ml). We conclude that traumatized brain parenchyma is a significant source of TNF activity and implicate the cytokine in cellular metabolic derangements following head injury.

Analyzing communication data within a social structure represented by a wholesale agricultural market demonstrates the utility of network analysis techniques for identifying systems. A representation of these data in matrix form permits exploration of the stability properties of the system. The stability analyses lend some support for theoretical arguments pertaining to the conditions leading to system equilibrium.

Jaundiced surgical patients have a high incidence of postoperative complications. Many causative factors have been identified including cachexia and immune suppression. The amino acid L-arginine has anabolic and immunostimulatory properties. It was hypothesized that dietary supplementation with L-arginine would diminish the weight loss and immune suppression of obstructive jaundice. Sixteen male Wistar rats rendered jaundiced by bile duct ligation were allocated to two groups. The test group (n = 8) received drinking water supplemented with 1·8 per cent L-arginine ad libitum and the control group (n = 8) received a solution of isonitrogenous glycine. Both groups had free access to standard chow. Body-weight, and fluid and food intake were recorded. After 21 days, delayed-type hypersensitivity to 2,4-dinitrofluorobenzene was assessed. Animals receiving L-arginine consumed more food than controls (mean(s.e.m.) 414(16) versus 360(13) g, P < 0·05) and lost less weight (mean(s.e.m.) proportion of initial body-weight lost 7·8(1·2) versus-14·8(1·4) per cent P < 0·05). The delayed-type hypersensitivity response was significantly greater in rats receiving L-arginine (mean(s.e.m.) increase in ear thickness 23·9(2·7) versus 9·4(2·1) per cent, P < 0·05). In this animal model of obstructive jaundice dietary supplementation with L-arginine diminished both weight loss and immune suppression.

Intestinal mucosal barrier dysfunction observed in patients undergoing transperitoneal abdominal aortic aneurysm (AAA) repair may contribute to the development of the systemic inflammatory response syndrome and dysfunction of various organs. The aim of this study is to investigate whether an extraperitoneal approach reduces intestinal mucosal barrier and renal dysfunction in elective infrarenal AAA repair.Twenty patients admitted for elective infrarenal AAA repair were randomized into either the transperitoneal approach (n=10) or the extraperitoneal approach (n=10). Intestinal permeability was measured preoperatively, and at day 1 and day 3 after surgery using the lactulose/mannitol test by calculating the differential urinary excretion ratio of the two sugars after oral administration. Renal dysfunction was assessed by measuring the urinary albumin/creatinine ratio (ACR) at the same time points.Intestinal permeability was significantly increased in the transperitoneal group at day 1 [0.124+/-0.035 (mean+/-s.e.m.)] compared to the preoperative level (0.020+/-0.003), (p=0.001) and to the extraperitoneal group at day 1 (0.025+/-0.008), (p0.05) which showed no change in comparison with the preoperative level (0.020+/-0.003). The ACR was also significantly increased in the transperitoneal group at day 1 (16.69+/-5.12) compared to the preoperative level (5.71+/-2.89), (p0.05) and to the extraperitoneal group at day 1 (4.33+/-1.49), (p0.05) which showed no significant change at any of the times examined. No correlation was observed between the lactulose/mannitol ratio and the albumin/creatinine ratio, or between age, operating time, aortic clamping time, amount of blood lost or blood transfused.These results support the suggestion that minimising intestinal manipulation using an extraperitoneal approach in AAA repair preserves intestinal mucosal barrier and renal glomerular functions.

Systemic endotoxaemia contributes to the high morbidity and mortality of jaundiced patiens undergoing surgery. In this study, correlations between systemic endotoxaemia (assessed by measuring antibodies to the core-glycolipid region of endotoxin, a-CGL), bile acids and blood histamine were investigated in a bile duct ligation (BDL) animal model of obstructive jaundice. Three weeks after BDL, systemic a-CGL (p

Objective: To assess the expression of plasma lipopolysaccharide binding protein (LBP) concentrations and its relationship to markers of the systemic inflammatory response syndrome during acute pancreatitis. Design: A prospective study. Setting: General surgical units of university teaching hospitals in the Belfast area. Patients: The study included 18 patients admitted with established diagnosis of acute pancreatitis on the basis of elevated serum amylase or by contrast radiology. Patients were retrospectively stratified using the Modified Glasgow Criteria into severe (n = 7) and mild (n = 11) disease. Interventions and Measurements: Blood samples were obtained at admission (day 1) and for a further 3 days for the measurement of LBP, C-reactive protein (CRP), tumor necrosis factor, and interleukin (IL)-6. Acute Physiology and Chronic Health Evaluation (APACHE) II scores were calculated on day 1 and day 2. Main Results: LBP and CRP concentrations were significantly increased from healthy control values in acute pancreatitis patients at presentation. In the mild group LBP, CRP and IL-6 concentrations remained relatively constant throughout the study period. By comparison, severe acute pancreatitis was associated with significantly higher LBP concentrations and a marked systemic inflammatory response as evidenced by increased CRP, IL-6, and APACHE II scores. The rise in LBP occurred after the observed increase of these markers. Significant correlations were found among CRP and LBP, IL-6 and LBP, and IL-6 and APACHE II scores. There were no fatalities in the mild group, whereas four of the seven patients with severe disease died. Conclusions: LBP was significantly raised in patients with severe acute pancreatitis but would seem to be of limited use in predicting disease severity. This acute phase protein may have a role in the progression of systemic complications associated with acute pancreatitis. Further clinical studies are warranted.

Background It has been suggested that reperfusion of the acutely ischaemic lower limb alters gut permeability. The effect of lower limb ischaemia–reperfusion on systemic endotoxin and antiendotoxin antibody concentrations and the incidence of bacterial translocation was investigated. Methods Systemic endotoxin and antiendotoxin antibody concentrations were measured in five groups of male Wistar rats: control, after 3 h of bilateral hind limb ischaemia alone, and after 3 h of bilateral hind limb ischaemia followed by 1, 2 or 3 h of reperfusion. A second experiment examined translocation of indigenous bacteria following 2 h of reperfusion in a similar model. Results Ischaemia followed by reperfusion for 1, 2 or 3 h caused a significant increase in plasma endotoxin concentration to mean(s.e.m.) 10·0(3·0), 44·8(19·2) and 20·2(6·2) pg/ml compared with that in control animals (2·58(0·91) pg/ml) or animals in the ischaemia alone group (1·2(0·9) pg/ml) (P < 0·05). This was associated with a significant reduction in endogenous antiendotoxin antibody (immunoglobulin (Ig) G and IgM) concentration. No significant bacterial translocation was detected in any of the groups studied. Conclusion These results demonstrate that a remote and isolated ischaemia–reperfusion injury to the lower limb, in the absence of infection or bacterial translocation, causes endotoxaemia. Further studies are needed to evaluate the role of endogenous antiendotoxin antibodies in this situation.

It has been suggested that bowel permeability is altered following abdominal aortic aneurysm surgery. The effect of ischaemia-reperfusion injury to the lower limb on the morphological structure, neutrophil infiltration and permeability of the bowel was investigated.Histological assessment of the bowel was undertaken in five groups of Wistar rats: control, 3 h of bilateral hind limb ischaemia and 3 h of bilateral hind limb ischaemia followed by 1, 2 or 3 h of reperfusion. Using an everted gut sac model and 14C-labelled polyethylene glycol, the effect of ischaemia-reperfusion on small bowel permeability was studied.The small bowel showed a significant decrease in mucosal thickness, villus height and crypt depth in animals subjected to ischaemia followed by 2-hr reperfusion (mean(s.e.m.) 420(15), 217(9) and 163(6) microns respectively) compared with controls (481(11), 245(6) and 195(6) microns) (P0.05). Neutrophil count within the lamina propria was similar in the different groups. A significant increase in mean(s.e.m.) 14C-labelled polyethylene glycol translocation was detected in animals subjected to ischaemia-reperfusion compared with controls (760(40) versus 560(27) c.p.m. per ml per h) (P0.05).These data suggest that reperfusion of acutely ischaemic extremities produces structural and functional changes in the small intestine, although these changes are not associated with increased neutrophil infiltration within the bowel wall.

Tumour necrosis factor (TNF) is a pleiotropic cytokine produced largely by macrophages and T lymphocytes. It has been implicated in the pathogenesis of numerous immunoinflammatory processes. Recently, a number of studies have indicated that anti-TNF antibodies may be of value in the treatment of inflammatory bowel disease.The literature is reviewed regarding the role of TNF in the pathogenesis of inflammatory bowel disease and the results of administering TNF inhibitors.TNF may have a role in the pathogenesis of inflammatory bowel disease. The effects of TNF inhibitors are complex and incompletely understood. Anti-TNF antibody strategies may have a role in the treatment of acute exacerbations of the disease but are unlikely to be appropriate therapies for long-term management.

Systemic tumour necrosis factor (TNF) is present in jaundiced mice. Two soluble TNF receptors, sTNFr-P55 and sTNFr-P75 are reported to play a part in the natural defence against TNF. This study investigated the properties of circulating TNF and sTNFr in jaundiced mice. The data show that TNF in these mice is biologically inactive and that an increase of both sTNFr is seen (p0.001). Surgical trauma in jaundiced mice is known to be accompanied by a high mortality (36%) and increased TNF concentrations. This study shows that both systemic TNF and sTNFr concentrations are increased after surgical trauma in jaundiced mice and that sTNFr concentrations rather than TNF concentrations were found to be correlated with mortality. In line with this finding this study showed that lactulose pretreatment before a surgical trauma in these mice significantly reduces postoperative concentrations of sTNFr-P75 (p0.005) and mortality (0%; p0.05) without reducing TNF concentrations, while anti-TNF antibodies were ineffective. In conclusion, these data suggest that TNF in biliary obstruction is rapidly inactivated by increased concentrations of sTNFr. Furthermore, sTNFr concentrations rather than TNF concentrations show a good correlation with mortality after surgery in obstructive jaundice. The positive effect of lactulose on mortality could be caused by a decreased inflammatory status.

Tumour necrosis factor (TNF) is a cytokine with multiple biological activities which plays a pivotal role in the response of the body to infection. TNF is secreted in the the monomeric form and associates to yield a biologically active oligomeric molecule. Bioactive TNF can be measured in plasma using cytotoxic assays which employ the murine cell-lines L929 or WEHI 164 clone 13. However, it has become clear that inactive TNF also circulates in vivo, which is not detected by bioassay. These inactive forms may play an important role in the regulation of TNF activity. The rat is often used as a model for the study of acute infection and its systemic effects. Our aim was to develop an ELISA for rat TNF which would provide a convenient and cost effective method of assay. The assay employs two commercially available antibodies raised against recombinant murine TNF (rMuTNF) which exhibit cross-reactivity with rat TNF. The lower limit of detection for this assay was determined to be 39.0 pg/ml rMuTNF. The inter and intra-assay coefficients of variation were12.0%. Specificity of the assay was shown by the high degree of parallelism obtained between rMuTNF and commercially available rRatTNF. The assay described measures rat TNF in both plasma and tissue culture supernatant. The measurement of plasma concentrations of TNF using both the ELISA and bioassay may help elucidate more fully the biological importance of TNF.

Bacterial translocation from the gut is implicated in the pathophysiology of complications associated with obstructive jaundice. Absence of intraluminal bile salts and their antiendotoxic effects may result in overgrowth of bacteria, promoting bacterial translocation. The large bowel is the largest source of gram negative bacteria but the small bowel is more permeable. This study investigated the effect of obstructive jaundice on bacterial translocation and on the indigenous luminal microflora at 3 sites in the gastrointestinal tract. Significant bacterial translocation was demonstrated following 7 d of bile duct ligation compared with control or sham operated groups. A qualitative disturbance of the caecal indigenous microflora was demonstrated in jaundiced rats. There was no 'site-to-site' variation in the indigenous microflora at the 3 intestinal sites studied. We conclude that experimental obstructive jaundice for 1 wk promotes bacterial translocation without significant quantitative disturbance of the intestinal microflora in the small intestinal or caecum.

The efficacy of lactulose as an antiendotoxin was studied and the effect of lactulose or colistin on faecal flora was investigated in a hapten-induced rat model of colitis. Enteral administration of lactulose to rats with colitis was associated with a significant reduction in the systemic concentration of endotoxin (median (range) 5.4 (0–19.9) versus 23.7 (0–145.0) pg/ml in colitic rats treated with water; 4.6 (0–10.8) pg/ml in healthy animals). Enteral administration of colistin significantly reduced the faecal count of aerobic Gram-negative bacilli (median (range) 2.84 (1.40–8.43) versus 8.26 (4.50–10.40) log10 colony-forming units per g faeces after treatment with water) but not the faecal load of endotoxin. Patients with inflammatory bowel disease may benefit from enteral treatment with lactulose to prevent systemic endotoxaemia and/or with colistin to modify enteric bacteria.

The indigenous intestinal flora and an intact mucosa are vital components of body defences against luminal pathogenic bacteria. Disruption of these defences in inflammatory bowel disease may permit bacterial translocation and contribute to disease severity. Support for this hypothesis comes from this study of a hapten-induced rat model of colitis. Induction of colitis was associated with a significantly increased colonic Gram-negative aerobic bacilli count. The results, expressed as log10 [colony-forming units per gram tissue] were: colitic 6.97–8.86 versus control 4.90–6.69 (P < 0.05). Colitis was also associated with a decreased Gram-positive cocci count at 4.00–8.04 versus control 6.45–8.30 (P < 0.05). Bacteria translocated to the mesenteric lymph nodes in five of eight colitic rats (P = 0.01), to the spleen in four (P = 0.04) and to the liver in five (P = 0.01) but to these organs in none of the eight control animals. There was a positive correlation between the severity of colonic inflammation and extent of bacterial translocation in colitic animals (rS = 0.86, P = 0.007).

The intestinal mucosa protects the body from a large reservoir of intraluminal pathogenic bacteria and endotoxins. This mucosal barrier is disrupted by the inflammation and ulceration of inflammatory bowel disease and may permit the absorption of toxic bacterial products. Systemic endotoxaemia has been demonstrated in ulcerative colitis and Crohn's disease and correlates with the extent and activity of disease. In this study the efficacy of absorbents as antiendotoxin agents in a hapten induced rat model of colitis is investigated. Induction of colitis was associated with systemic endotoxaemia. Enteral administration of terra fullonica and kaolin, but not of charcoal, significantly reduced systemic endotoxaemia (terra fullonica 4.2 (1.40) pg/ml; kaolin 5.29 (1.86) pg/ml; charcoal 32.7 (16.6) pg/ml; water 39.8 (12.6) pg/ml). Data expressed as mean (SE). With increasing severity of colitis, there was a decreasing ability of adsorbent therapy (terra fullonica) to control systemic endotoxaemia. Enteral administration of adsorbents controls gut derived systemic endotoxaemia in experimental colitis in animals and may be a useful antiendotoxin treatment in patients with inflammatory bowel disease.

Enteric bacteria and their products (endotoxins) have attracted attention as luminal antigens that may initiate or contribute to the enterocolitis and associated systemic illness of inflammatory bowel disease (IBD). It has been proposed that endotoxins originating from these intestinal flora cross the disrupted intestinal mucosal barrier of patients with IBD to enter the portal circulation [1]. If the hepatic capacity to eliminate endotoxins is exceeded, spillover into the systemic circulation occurs (Fig. 1). Systemic endotoxaemia has been demonstrated in ulcerative colitis and Crohn’s disease and shown to correlate positively with disease activity [1, 2].

Background: Clinical experience of the early use of intraluminal shunts in major limb trauma at this centre aimed at restoring arterial inflow and venous outflow has been shown to reduce amputation rates and morbidity. In a model of combined arterial and venous limb vessel trauma, ischaemia–reperfusion injury caused by delayed restoration of venous drainage locally on skeletal muscle and remotely on lung was studied. Furthermore, using antioxidant pretreatment the possibility of reversing these detrimental effects was investigated. Methods: New Zealand white rabbits (n = 36) were randomized into six groups: (1) sham operation; unilateral hind limb arterial and venous occlusion for 1 h followed by (2) no reflow for 2 h; (3) arterial and venous reflow for 2 h; (4) arterial reflow alone for 2 h; (5) arterial reflow for 1 h followed by arterial and venous (delayed) reflow for a further 1 h; (6) pretreatment with an enteral combination antioxidant before combined arterial and venous occlusion with delayed venous reflow. Plasma hydroperoxide (HPO) concentration in the femoral vein was a measure of lipid peroxidation. Hindlimb skeletal muscle and lung wet-to-dry weight ratio reflected tissue oedema, and myeloperoxidase (MPO) tissue levels estimated neutrophil sequestration. Plasma glutathione peroxidase (GPx) levels in systemic vein (SV) and femoral vein effluent (FV) reflected antioxidant status. Hindlimb skeletal muscle injury was graded histologically. Results: Femoral vein HPO (µmol l−1) GPx (units l−1) Lung MPO (units g−1) Skeletal muscle histological injury grade SV start SV end FV end Values are mean(s.e.m.). * P < 0·05 versus groups 1, 3 and 6 † P < 0·01 versus groups 1–5 ‡ P < 0·05 versus group 1 1 1·0(0·1) 414·9(31·7) 391·4(33·4) 440·1(47·2) 1·7(0·1) None 2 1·8(0·5) 291·7(10·9) 363·2(62·4) 488·6(45·6) 2·3(0·2) None 3 1·2(0·4) 423·1(68·3) 398·6(63·9) 409·1(63·9) 2·4(0·2) Mild 4 1·7(0·3) 408·8(26·4) 399·0(35·4) 397·3(26·4) 1·9(0·2) Moderate 5 2·0(0·5)* 468·0(40·8) 412·2(35·6) 358·4(22·0) 3·2(0·3)‡ Severe 6 0·9(0·2) 607·9(36·3)† 562·3(40·7)† 547·2(24·9)† 2·1(0·3) Mild Conclusion: In combined major arterial and venous vessel injury of the limb, delayed venous repair leads to significantly greater local skeletal muscle injury and remote neutrophil-mediated lung damage. Reversal of these detrimental effects with antioxidant pretreatment suggests that failure of antioxidant scavenging systems may be central to the injury accentuated by delayed venous drainage. These results support the clinical rationale for early restoration of not only arterial inflow but also venous drainage by intraluminal shunts. © 2000 British Journal of Surgery Society Ltd