Prophylactic antibiotics in acute pancreatitis: endless debate.

INTRODUCTION The development of pancreatic infection is associated with the development of a deteriorating disease with subsequent high morbidity and mortality. There is agreement that in mild pancreatitis there is no need to use antibiotics; in severe pancreatitis it would appear to be a logical choice to use antibiotics to prevent secondary pancreatic infection and decrease associated mortality. MATERIALS AND METHODS A non-systematic review of current evidence, meta-analyses and randomized controlled trials was conducted to assess the role of prophylactic antibiotics in acute pancreatitis and whether it might improve morbidity and mortality in pancreatitis. RESULTS Mixed evidence was found to support and refute the role of prophylactic antibiotics in acute pancreatitis. Most studies have failed to demonstrate much benefit from its routine use. Data from our unit suggested little benefit of their routine use, and showed that the mortality of those treated with antibiotics was significantly higher compared with those not treated with antibiotics (9% vs 0%, respectively, P = 0.043). In addition, the antibiotic group had significantly higher morbidity (36% vs 5%, respectively, P = 0.002). CONCLUSIONS Antibiotics should be used in patients who develop sepsis, infected necrosis-related systemic inflammatory response syndrome, multiple organ dysfunction syndrome or pancreatic and extra-pancreatic infection. Despite the many other factors that should be considered, prompt antibiotic therapy is recommended once inflammatory markers are raised, to prevent secondary pancreatic infection. Unfortunately, there remain many unanswered questions regarding the indications for antibiotic administration and the patients who benefit from antibiotic treatment in acute pancreatitis.

Erosion and perforation of the biliary tree by plastic biliary endoprostheses.

Biliary endoprostheses are increasingly used in the treatment of both benign and malignant pancreaticobiliary disorders. Common bile duct stones are a common clinical problem for which there now exist a range of treatment modalities. Official guidelines in the UK advocate the use of plastic biliary endoprostheses in the treatment of common bile duct stones only as a short-term measure prior to definitive endoscopic or surgical clearance. Long-term use of such stents is associated with several complications related to stent insertion, occlusion, and migration. Organ perforation resulting from plastic biliary stents is very rare and can occur either as an early complication at stent insertion or as a late complication resulting from stent migration and pressure necrosis. Although duodenal, small-bowel, and colonic perforations have been described, we have found no reports of extra-hepatic bile duct perforation occurring as a complication of plastic biliary stents. We present three cases of biliary tree erosion and perforation by plastic stents placed in patients with common bile duct stones cleared endoscopically prior to laparoscopic cholecystectomy and discuss the possible implications of this previously unreported phenomenon.

Inhibition of nitric oxide and caspase-3 mediated apoptosis by a tetrapeptide derivative (PEP1261) in cultured synovial fibroblasts from collagen-induced arthritis.

In this study, the effect of (Boc-Lys (Boc)-Arg-Asp-Ser (tBu)-OtBu), a tetrapeptide derivative (PEP1261) was examined for antiproliferative potency and apoptotic induction. Synovial fibroblasts were isolated from collagen-induced arthritic (CIA) rats and exposed to peptides viz., PEP1261, and parental peptides (KRDS and RGDS). Viability of the cells decreased in the presence of PEP1261 at a lower concentration (0.1 mM) when compared to RGDS and KRDS (1 mM). The treatment of cells with peptides showed induction of apoptosis, resulting in the cleavage of caspase-3 as well as its substrate poly-(ADP-ribose) polymerase (PARP). Pretreatment of cells with caspase-3 inhibitor prevented inhibition of [(3)H] thymidine incorporation, DNA fragmentation, and cleavage of caspase-3 and PARP as confirmed by western blotting as well as annexin-V/PI-staining using flow cytometry. However, caspase-1 and caspase-2 inhibitors did not prevent the peptides from inducing apoptosis indicating that caspase-3 might have a role in the process of apoptosis induced by peptides. Treatment of synovial fibroblasts with nitric oxide donor, S-nitroso-N-acetyl-DL: -penicillamine (SNAP) (500 microM) showed significant elevation of nitric oxide levels and resulted in absence of apoptosis by preventing the inhibition of [(3)H] thymidine incorporation. This was further evidenced by annexin V/propidium iodide (PI) staining and absence of DNA fragmentation, intra cellular caspase-3 activity and PARP cleavage. In contrast, SNAP followed by PEP1261 and parental peptides-induced apoptosis by lowering the levels of nitric oxide. These results suggested that PEP1261 suppressed the proliferation and induced apoptosis in cultured synovial fibroblasts from CIA rats. This study also confirmed that PEP1261 inhibited nitric oxide level in cultured synovial fibroblasts.

Effect of a derivatized tetrapeptide from lactoferrin on nitric oxide mediated matrix metalloproteinase-2 production by synovial fibroblasts in collagen-induced arthritis in rats.

Matrix metalloproteinases (MMPs) constitute a family of zinc-dependent proteolytic enzymes, which degrade several components of extracellular matrix, in arthritic synovial cells. In cultured synovial fibroblasts, both nitric oxide (NO) and reactive oxygen species (ROS) are potent inducers of MMPs production. PEP1261, a tetrapeptide derivative used in this study, corresponds to residues of 39-42 human lactoferrin. The parent protein lactoferrin is able to inhibit the production of free radicals in rheumatoid joints and it regulates many aspects of inflammation. This study is aimed to examine the effects of PEP1261 on MMP-2 production in the presence of nitric oxide donor in cultured synovial fibroblasts from collagen-induced arthritic rats. PEP1261 affects a significant reduction in nitrite levels as well as in MMP-2 production in SNAP stimulated synovial fibroblasts and this is validated by gelatin zymography and immunoblot analysis. Furthermore, RTPCR analysis has demonstrated that PEP1261 inhibits MMP-2 mRNA expression in SNAP treated synovial fibroblasts. The results of this study suggest that PEP1261 possesses antiarthritic activity by inhibiting nitrite levels as well as MMP-2 expression better than control peptides viz., KRDS and RGDS.

A novel peptide derivative exhibits anti inflammatory and antioxidant activity in adjuvant induced arthritis in rats.

A tetrapeptide derivative PEP1261 [Boc-Lys-(Boc)-Arg-Asp-Ser-(tBu)-OtBu], corresponding to residues 39-42 of human lactoferrin, was tested for its antiinflammatory action in adjuvant induced arthritis in rats. Administration of heat killed Mycobacterium tuberculosis (500 microg/0.1 ml of paraffin oil) intradermally into the foot pad of right hind paw resulted in an increased paw volume and an increase in the levels of reactive oxygen species and beta-glucuronidase as well as a decrease in the antioxidants levels. PEP1261, at an effective dose of 10 mg/kg body wt., exhibited a significant antiarthritic activity as evidenced by lowering of paw volume and inhibited the free radicals toxicity by increasing the antioxidants levels. This peptide derivative was also shown to have a membrane stabilizing action by significantly decreasing the total and free activity of beta-glucuronidase and inhibiting the rate of release of the enzyme from lysosomal rich fraction. Histopathological studies confirmed the above results by showing a decrease in mononuclear cell infiltration, hypertrophy, hyperplasia and pannus formation after PEP1261 treatment in arthritic rats.

Acute changes in endothelin-1 after hemodialysis for chronic renal failure.

Endothelin is a recently described, potent renal vascular and systemic vasoconstrictor peptide. To evaluate the response of this peptide to volume contraction, we measured eight baseline and posthemodialysis samples from seven children, aged 14.5 +/- 3 years, with chronic renal failure. Plasma was extracted and endothelin-1 was measured by radioimmunoassay. Dialysis was performed for a 3- to 3 1/2-hour period, and body weight decreased from 38.0 +/- 14.3 to 36.2 +/- 13.8 kg (p < 0.01) during this time. There were no significant changes in heart rate or respiratory rate after dialysis, but blood pressure fell from 127/80 +/- 22/16 to 114/72 +/- 20/21 mm Hg (p = 0.05 for the systolic pressure). Plasma endothelin-1 concentration increased from 1.5 +/- 1.2 pg/ml at baseline to 7.3 +/- 8.9 pg/ml (p = 0.06) after dialysis; the fall in body weight from dialysis correlated with the increase in endothelin (r = -0.75; p = 0.05). Thus volume contraction from hemodialysis is associated with a rise in plasma endothelin-1, which is related to the acute change in body weight.