Rat and human aortic smooth muscle cells display differing migration and matrix metalloproteinase activities in response to dexamethasone.

OBJECTIVE: The steroid dexamethasone inhibits neointimal hyperplasia development in rats but not in humans. This study investigates the differential effects of dexamethasone on rat and human smooth muscle cell migration and matrix metalloproteinase (MMP) activity. METHODS: Rat aortic smooth muscle cells were harvested from Sprague-Dawley rats. Human aortic smooth muscle cells were obtained from Clonetics. Boyden chamber migration assays were performed with chemoattractant (platelet-derived growth factor) and varying concentrations of dexamethasone (10(-9) to 10(-5) mol/L). Zymography of culture media was used to assess MMP activity, and Western blot analysis was used for quantification of MMP-2 and tissue inhibitor of MMP-2 (TIMP-2) secretion. RESULTS: Dexamethasone inhibits rat aortic smooth muscle cell migration in a dose-dependent fashion. An increase in concentrations of dexamethasone does not effect human aortic smooth muscle cell migration. Rat aortic smooth muscle cell MMP-2 activity is inhibited with dexamethasone in a dose-dependent fashion, and human aortic smooth muscle cell MMP-2 activity is unchanged with dexamethasone. MMP-2 secretion is inhibited with dexamethasone in rat aortic smooth muscle cells but remains unaltered in human aortic smooth muscle cells. Dexamethasone increases rat aortic smooth muscle cell TIMP-2 secretion, and human aortic smooth muscle cell TIMP-2 secretion remains constant. CONCLUSION: Dexamethasone inhibits rat aortic smooth muscle cell migration, MMP-2 activity, and MMP-2 secretion and increases TIMP-2 secretion. These effects are not observed in human aortic smooth muscle cells. These findings may explain why dexamethasone inhibits neointimal hyperplasia in animal models but is ineffective in humans. Inhibition of human smooth muscle cell migration in vitro may be useful in predicting the effectiveness of future therapeutic agents for treatment of neointimal hyperplasia in humans.

Dexamethasone inhibits vascular smooth muscle cell migration via modulation of matrix metalloproteinase activity.

BACKGROUND: Dexamethasone (DEX) has been shown to inhibit development of neointimal hyperplasia in rats. We hypothesize that DEX inhibits neointimal hyperplasia by altering matrix metalloproteinase (MMP) activity, resulting in inhibition of smooth muscle cell migration. METHODS: Rat aortic smooth muscle cells (RASMC) were harvested and cultured for two to four passages. A migration assay was performed in a Boyden chamber with chemoattractant (platelet-derived growth factor) and varying concentrations of DEX (10(-9) to 10(-5) M). The number of migrated cells was counted under light microscopy. Zymography was performed on culture media to assess MMP activity, and Western blotting was performed to assay MMP and levels of tissue inhibitors of MMPs (TIMPs). RESULTS: DEX progressively inhibited RASMC migration in a dose-dependent fashion. This effect was statistically significant for concentrations of 10(-7) to 10(-5) M (P < 0.0005). Zymography showed that DEX inhibits MMP-2 activity in a dose-dependent manner. Western blots indicated that total MMP-2 secretion was inhibited and that TIMP-2 secretion was increased by DEX. CONCLUSIONS: DEX inhibits platelet-derived growth factor-induced migration of RASMCs and MMP-2 activity in vitro. Our data suggest that DEX suppresses MMP activity and secretion, resulting in the inhibition of smooth muscle cell migration. This may explain the mechanism by which DEX inhibits neointimal hyperplasia.

Platelet activating factor antagonism reduces the systemic inflammatory response in a murine model of acute pancreatitis.

BACKGROUND: The platelet activating factor (PAF) antagonist, Lexipafant, has been used in experimental models and clinical trials to treat severe acute pancreatitis (AP). The purpose of this study was to determine whether Lexipafant reduces the local and systemic components of AP in a murine model of mild, edematous AP. MATERIALS AND METHODS: Forty-eight female Swiss-Webster mice were divided into four groups. Group 1 received 50 microl of saline ip every hour for 6 h (sham). Group 2 received saline treatment, plus Lexipafant (25 mg/kg dose ip, every 3 h starting 1 h after the first saline injection) (sham/Lex). Group 3 received cerulein (50 microg/kg dose ip, every hour for 6 h) (AP). Group 4 received AP, plus therapeutic treatment with Lexipafant (AP/Lex). Animals were sacrificed 3 h after the last injection. Serum cytokine levels were determined by ELISA. Standard assays were performed for serum amylase activity and lung myeloperoxidase activity (MPO). Histology was scored by two blinded investigators. RESULTS: Serum cytokines (TNFalpha, IL-1beta), lung MPO, and serum amylase activity were reduced by PAF antagonism. Histology showed a trend toward improvement with Lexipafant, but did not reach statistical significance. CONCLUSION: The PAF antagonism reduces the severity of systemic inflammation when given after the induction of mild AP in mice. These results suggest that Lexipafant may be useful in the treatment of mild pancreatitis after its clinical onset.

Ileocecectomy is definitive treatment for advanced appendicitis.

Although appendectomy is the most commonly performed emergency operation septic complications of appendectomy remain a major source of morbidity. Historically, advanced appendicitis has been treated by appendectomy with cecostomy and/or drainage tubes. Our objective was to evaluate the use of ileocecal resection for the immediate treatment of advanced appendicitis. We examined the cases of all patients undergoing ileocecal resection for appendicitis from August 1989 through April 2000. There were 92 patients (60 male and 32 female) with a median age of 34 (range 6-71). Abdominal pain was present in 98 per cent of patients with duration of 5.1+/-0.6 days. Right lower quadrant tenderness was present in 91 per cent with accompanying right lower quadrant mass in 30 per cent. Temperature on admission was 38.0+/-0.1 degrees C with a white blood cell count of 15,300+/-500. Preoperative radiological studies included abdominal X-rays (33), contrast enemas (two), CT scans (41), and abdominal ultrasound (17); these studies yielded a correct preoperative diagnosis in 89 per cent. Previous appendectomy had been performed in six patients with failed percutaneous drainage of intra-abdominal abscesses in five. There were 94 cecal resections performed in 92 patients. The extent of surgical resection varied between patients and ranged from partial cecectomy (34) to ileocecectomy (55) to ileocecectomy with diverting ileostomy (five). Intra-abdominal abscesses were present at operation in 46 cases (50%), and drains were placed in 38 (41%). Skin incisions were packed open in most cases (65); there was skin closure in 27. There was no mortality encountered in this period. There were 25 complications in 23 patients (25%). Complications included postoperative abscess (10; 11%), wound infection (10; 11%), partial small bowel obstruction (two) and pulmonary embolus (one). Reoperation was required in seven patients and CT-guided percutaneous drainage in five patients. Anastomic leaks occurred in two cases of partial cecectomy and required conversion to ileocecectomy. Mean hospital stay was 10.5+/-1.0 days with adjusted hospital costs of $31,689+/-3018. We conclude that definitive treatment of advanced appendicitis can be performed by resection of the involved areas of the ileocecum. This can be accomplished with a primary anastomosis obviating the need for ileostomy and secondary operation. This aggressive surgical approach may reduce infectious complications and reduce hospital costs.

Kupffer cell blockade reduces hepatic and systemic cytokine levels and lung injury in hemorrhagic pancreatitis in rats.

Severe acute pancreatitis (AP) is associated with both the local (pancreatic) release of cytokines and an elevation in their systemic plasma concentrations. This may lead to organ dysfunction and death of the patient. The aims of this study were to investigate the source(s) of systemic cytokine production during experimental AP. Forty-two rats were allocated to five groups (control, sham operation and saline injection, sham operation and gadolinium chloride injection, intraductal sodium-taurocholate infusion and saline injection, or intraductal sodium-taurocholate infusion and gadolinium chloride injection). Blood from the iliac artery, portal vein, and hepatic vein, along with tissue from the pancreas, liver, and lung, were collected. Serum levels of TNFalpha, IL-1beta, IL-6, and IL-10 were determined by enzyme-linked immunosorbent assay. Tissue mRNA for IL-1beta and IL-10 was assessed by reverse-transcription polymerase chain reaction. In untreated animals with AP, the lowest serum cytokine levels were found in the portal vein. In the hepatic vein, the levels of TNFalpha, IL-1beta, and IL-6 were higher. The highest serum levels were detected in the systemic circulation. In the gadolinium chloride-treated group, there was no increase in hepatic or systemic cytokine levels and less lung injury was observed. Extrapancreatic cytokine production from both the liver and the lung contributed significantly to systemic levels of TNFalpha, IL-1beta, IL-6, and IL-10 in this experimental model of AP.

Luminal and systemic signals trigger intestinal adaptation in the juvenile python.

Juvenile pythons undergo large rapid upregulation of intestinal mass and intestinal transporter activities upon feeding. Because it is also easy to do surgery on pythons and to maintain them in the laboratory, we used a python model to examine signals and agents for intestinal adaptation. We surgically isolated the middle third of the small intestine from enteric continuity, leaving its mesenteric nerve and vascular supply intact. Intestinal continuity was restored by an end-to-end anastomosis between the proximal and distal thirds. Within 24 h of the snake's feeding, the reanastomosed proximal and distal segments (receiving luminal nutrients) had upregulated amino acid and glucose uptakes by up to 15-fold, had doubled intestinal mass, and thereby soon achieved total nutrient uptake capacities equal to those of the normal fed full-length intestine. At this time, however, the isolated middle segment, receiving no luminal nutrients, experienced no changes from the fasted state in either nutrient uptakes or in morphology. By 3 days postfeeding, the isolated middle segment had upregulated nutrient uptakes to the same levels as the reanastomosed proximal and distal segments, but it still lacked any appreciable morphological response. These contrasting results for the reanastomosed intestine and for the isolated middle segment suggest that luminal nutrients and/or pancreatic biliary secretions are the agents triggering rapid upregulation of transporters and of intestinal mass and that systemic nerve or hormonal signals later trigger transporter regulation but no trophic response.

Prospective evaluation of early versus delayed laparoscopic cholecystectomy for treatment of acute cholecystitis.

Although laparoscopic cholecystectomy (LC) is known to be safe in the treatment of acute cholecystitis (AC), the optimal timing of laparoscopic intervention remains controversial. The objective of this study is to prospectively compare the safety and cost effectiveness of early versus delayed LC in AC. Our study population consisted of 43 patients presenting with AC (localized tenderness, white blood cell count >10.0 or temperature >38.0 degrees C, and ultrasound confirmation) who were prospectively randomized to early versus delayed LC during their first admission. Exclusion criteria included a history of peptic ulcer disease or evidence of gallbladder perforation. All patients were treated with bowel rest and antibiotics (piperacillin 2 g intravenous piggyback every 6 hours). Early treatment patients underwent LC as soon as the operating schedule allowed. Delayed treatment patients received anti-inflammatory medication (indomethacin 50 mg per rectum every 12 hours) in addition to bowel rest and antibiotics and underwent operation after resolution of symptoms or within 5 days if symptoms failed to resolve. Early LC was performed in 21 patients, whereas 22 patients underwent delayed LC. There was no difference in age, temperature, or white blood cell count on admission between groups. Early LC slightly reduced operative time and conversion rate. There was no difference in complications. Estimated blood loss was significantly lower in those receiving early LC. There was also a significant reduction in total hospital stay and hospital charges with early LC. We conclude that delay in operation combined with anti-inflammatory medication showed no advantage with regard to operative time, conversion, or complication rate. Furthermore, early laparoscopic intervention significantly reduced operative blood loss, hospital days, and hospital charges.

Surgical approach to cecal diverticulitis.

BACKGROUND: Cecal diverticulitis is a rare condition in the Western world, with a higher incidence in people of Asian descent. The treatment for cecal diverticulitis has ranged from expectant medical management, which is similar to uncomplicated left-sided diverticulitis, to right hemicolectomy. STUDY DESIGN: A retrospective chart review was conducted of the 49 patients treated for cecal diverticulitis at Olive View-UCLA Medical Center from 1976 to 1998. This was the largest-ever single-institution review of cecal diverticulitis reported in the mainland US. RESULTS: The clinical presentation was similar to that of acute appendicitis, with abdominal pain, low-grade fever, nausea/vomiting, abdominal tenderness, and leukocytosis. Operations performed included right hemicolectomy in 39 patients (80%), diverticulectomy in 7 patients (14%), and appendectomy with drainage of intraabdominal abscess in 3 patients (6%). Of the 7 patients who had diverticulectomy, 1 required right hemicolectomy at 6 months followup for continued symptoms. Of the three patients who underwent appendectomy with drainage, all required subsequent hemicolectomy for continued inflammation. Of the 39 patients who received immediate hemicolectomies, there were complications in 7 (18%), with no mortality. CONCLUSIONS: We endorse an aggressive operative approach to the management of cecal diverticulitis, with the resection of all clinically apparent disease at the time of the initial operation. In cases of a solitary diverticulum, we recommend the use of diverticulectomy when it is technically feasible. When confronted with multiple diverticuli and cecal phlegmon, or when neoplastic disease cannot be excluded, we advocate immediate right hemicolectomy. This procedure can be safely performed in the unprepared colon with few complications. Excisional treatment for cecal diverticulitis prevents the recurrence of symptoms, which may be more common in the Western population.

Paracellular glucose transport plays a minor role in the unanesthetized dog.

Traditionally, intestinal glucose absorption was thought to occur through active, carrier-mediated transport. However, proponents of paracellular transport have argued that previous experiments neglected effects of solvent drag coming from high local concentrations of glucose at the brush-border membrane. The purpose of this study was to evaluate glucose absorption in the awake dog under conditions that would maximize any contribution of paracellular transport. Jejunal Thiry-Vella loops were constructed in six female mongrel dogs. After surgical recovery, isotonic buffers containing L-glucose as the probe for paracellular permeability were given over 2-h periods by constant infusion pump. At physiological concentrations of D-glucose (1-50 mM), the fractional absorption of L-glucose was only 4-7% of total glucose absorption. Infusion of supraphysiological concentrations (150 mM) of D-glucose, D-maltose, or D-mannitol yielded low-fractional absorptions of L-glucose (2-5%), so too did complex or nonabsorbable carbohydrates. In all experiments, there was significant fractional water absorption (5-19%), a prerequisite for solvent drag. Therefore, with even up to high concentrations of luminal carbohydrates in the presence of significant water absorption, the relative contribution of paracellular glucose absorption remained low.

Resection of locally advanced pancreatic cancer after downstaging with continuous-infusion 5-fluorouracil, mitomycin-C, leucovorin, and dipyridamole.

Patients with locally advanced pancreatic adenocarcinoma who receive conventional therapy with radiation with 5-fluorouracil (5-FU) have median survivals ranging from 8 to 12 months. Here we report our experience with a four-drug chemotherapeutic regimen that resulted in sufficient downstaging of tumor in some patients to justify surgical reexploration and resection. From April 1991 through April 1994, 38 patients received 5-FU as a continuous infusion (200 mg/m2/day), calcium leucovorin weekly by intravenous bolus injection (30 mg/m2), mitomycin-C every 6 weeks (10 mg/m2 intravenously), and dipyridamole daily orally (75 mg) for locally advanced unresected pancreatic cancer. All of these patients were evaluable for response, toxicity, and survival. There were 14 partial responses and one complete response--a 39% response rate. The median survival for all patients was 15.5 months; the 1-year survival rate from time of initial diagnosis was 70%. Six of 15 responding patients had sufficient tumor regression to meet clinical criteria for resectability and reexploration, four of whom underwent a curative resection. The median survival of these six patients was 28 months from the time of original diagnosis. The 1-year survival was 83%, with one patient still alive and free of disease at 53 months. We believe this unique experience from a single institution justifies a prospective multi-institutional trial to evaluate the efficacy of this approach in a larger number of patients.

Hepatic Kupffer cell blockade reduces mortality of acute hemorrhagic pancreatitis in mice.

Inflammatory cytoklines derived from the liver may cause distant organ failure and death in severe pancreatitis. To minimize liver cytokine release, we studied the effects of Kupffer cell blockade on the mortality rate and severity of inflammation in a model of that disease. Thirty mice were divided into three groups. Group I received gadolinium chloride (l mg/100 g intravenously), which blocks Kupffer cell activity, and regular food. Groups 2 and 3 were fed a choline-deficient, ethionine-supplemented diet and developed severe pancreatitis. Group 2 (control) received intravenous saline solution, and group 3 received gadolinium chloride. Animals were killed at 72 hours. Serum levels of tumor necrosis factor-alpha and interleukin-1Beta, interleukin-6, and interleukin-10 were determined by enzyme-linked immunosorbent assay. Lung neutrophil infiltration was assessed by myeloperoxidase assay. Pancreatic inflammation was scored in a blinded manner. In a separate experiment, mortality rates were determined in saline- and gadolinium-treated animals (n=100). Gadolinium reduced the levels of all the cytoklines and lung myeloperoxidase (P<0.05). Gadolinium also reduced the mortality rate (52% vs. 86%; P <0.001). However, the degree of pancreatic inflammation was unchanged by gadolinium treatment. These data support the hypothesis that mortality in severe pancreatitis may in part be related to the secondary release of hepatic cytokines.

Mechanism of increased lung injury after acute pancreatitis in IL-10 knockout mice.

BACKGROUND: IL-10 is a potent anti-inflammatory cytokine which inhibits inflammatory cytokine release from all tissue sites. Hepatic cytokine release from Kupffer cells (KC) is one important source of inflammatory cytokines and may be the main one causing lung damage in acute pancreatitis (AP). Here we studied the KC contribution to lung injury in IL-10 knockout (KO) mice, in which tissue inflammatory cytokine release from all sites is unrestrained, and AP is more severe. METHODS: Three- to 4-week-old C57BL/6J mice and KO mice on a C57BL/6J background were used. Control mice received regular chow and gadolinium chloride (GD; 1 mg/100 g iv), to inhibit KC activity, or saline. Pancreatitis mice received a choline-deficient, ethionine-supplemented diet for 66 h to induce AP and saline or GD injections iv. After 66 h, lung tissue was assessed for edema, myeloperoxidase (MPO), and superoxide dismutase (SOD). Histology was scored in a blinded fashion. RESULTS: In pancreatitis KO mice, KC blockade had no effect on the degree of lung edema, lung neutrophil infiltration, and lung histology score. As expected, each of these parameters was more severe in the KO mice than in the normal mice: lung wet/dry ratio 5.3 +/- 0.2 versus 4.3 +/- 0.13; lung MPO (U/g) 1.9 +/- 0.2 versus 1.1 +/- 0.08; histology score 7.1 +/- 0.8 versus 5.3 +/- 0.5. CONCLUSION: Endogenous IL-10 is important in reducing the lung injury in this model of AP. KC-derived cytokines were of minor importance, compared to those derived from all other tissue sites.

Diverting loop versus end ileostomy during ileoanal pullthrough procedure for ulcerative colitis.

A two-stage ileoanal pullthrough procedure (IAPP) is often used for patients with ulcerative colitis (UC) requiring proctocolectomy. We analyzed the recent University of California at Los Angeles experience with diverting end and loop ileostomies in patients undergoing a two-stage IAPP. A retrospective analysis of 21 patients with UC undergoing loop ileostomy between March 1992 and March 1995 was performed. Comparison was made with 21 age- and gender-matched patients undergoing end ileostomy between January 1991 and December 1995. There was no mortality or major septic complications. A second laparotomy was required in all patients with end ileostomies, whereas loop ileostomies were closed without abdominal exploration. During ileostomy closure, operative time and mean hospital stay were significantly reduced with the use of loop ileostomy. The time to oral feeding was not significantly different between end and loop ileostomy groups after ileostomy closure. The complication rate after IAPP was similar between groups. However, after ileostomy closure, the complication rate was significantly reduced with the use of loop ileostomy. We conclude that loop ileostomy is a desirable option for UC patients undergoing intestinal diversion during IAPP. Loop ileostomies can be created easily and without an increase in operative time. Subsequent ileostomy closure can be performed as a local procedure, which may shorten operative time and length of hospital stay.

p21 expression is increased by irradiation in esophageal squamous cell carcinoma.

The p21 cyclin-dependent kinase inhibitor blocks cell cycle transition and replication in response to DNA damage. Although required for p53-mediated cell cycle arrest, p21 expression can also be initiated via p53-independent pathways. This study examines the postirradiation expression of p21 in squamous cell carcinoma (SCC) of the esophagus to determine whether this p21 production is p53-dependent or independent. We sequenced p53 exons 5-8 and the exon-intron junctions of four esophageal SCC lines, KYSEs 30, 150, 410, and 960. We exposed these same lines to increasing doses of radiation (3 to 24 Gy) and subsequently extracted their total protein. The p21 content of the protein was then determined via p21 ELISA. The same cell lines were also irradiated for determination of clonogenic survival over the course of 7 days. Cells were counted via a Coulter machine. KYSE 30 and 410 were found to have mutations in their p53 genes, while KYSEs 150 and 960 had wild-type p53 genomes. All cell lines produced basal levels of p21 (from 3.2 to 7.8 ng/ml) and all lines increased production in response to radiation (6.4 to 16.8 ng/ml at 3 Gy, P < 0.05 for all lines vs. their controls). Cells displayed dose-dependent mortality in response to radiation, with only minor differences in survival between two of the lines. All of the esophageal SCC lines studied produced basal p21 and increased p21 with irradiation. p21 production was independent of p53 status. Previous reports have failed to detect elevation of p21 expression in esophageal SCC, and this is the first report of radiation-induced p21 expression in esophageal cell lines.

Seatbelt sign following blunt trauma is associated with increased incidence of abdominal injury.

The use of seatbelts has reduced the overall mortality associated with motor vehicle accidents. The use of lap belts has, however, been associated with a constellation of abdominal injuries, which has been termed "the seatbelt syndrome." Previous studies have shown no increase in overall rates of abdominal injury but an increase in intestinal injury with the use of lap belts. Retrospective reviews suggest that the presence of a "seatbelt sign" may further increase the risk of intestinal injury. The purpose of this study is to prospectively evaluate the incidence of abdominal and intestinal injuries in patients with a "seatbelt sign." A consecutive sample of 117 adult motor vehicle accident victims were studied between July 1993 and January 1994. The use of seatbelts and the presence or absence of a seatbelt sign were determined on admission. Patients were evaluated with computed tomography scan of the abdomen, diagnostic peritoneal lavage, serial abdominal examinations, and operative findings. On arrival, 14 of 117 (12%) had an abdominal seatbelt sign. Of these 14, 9 (64%) had abdominal injury, 5 (36%) required operative intervention, and 3 (21%) had small bowel perforation. In contrast, the 103 patients without a seatbelt sign had significantly fewer abdominal injuries (9; 8.7%), laparotomies (4; 3.8%), and small intestine perforations (2; 103; 1.9%). We conclude that the presence of a seatbelt sign is associated with an increased likelihood of abdominal and intestinal injuries and mandates a heightened index of suspicion.

Interleukin-10 reduces the systemic inflammatory response in a murine model of intestinal ischemia/reperfusion.

BACKGROUND: Intestinal ischemia/reperfusion (I/R) is known to increase systemic cytokine levels, as well as to activate neutrophils in distant organs. This study was designed to investigate the effect of interleukin-10 (IL-10) on cytokine release, pulmonary neutrophil accumulation, and histologic changes in a murine model of I/R. METHODS: Forty female Swiss-Webster mice were divided into four groups. Group 1 underwent 45 minutes of superior mesenteric artery occlusion followed by 3-hour reperfusion (I/R). Group 2 underwent laparotomy alone (Sham). Group 3 underwent I/R, but was treated with IL-10, 10,000 units IP every 2 hours, starting 1 hour before reperfusion (Pretreatment). Group 4 was treated with an equal dose of IL-10, starting 1 hour after reperfusion (Posttreatment). All animals were killed at 3 hours, standard assays were performed for serum cytokine levels, and lung myeloperoxidase activity and intestinal histology were scored. RESULTS: Serum cytokines (TNF-alpha and IL-6), lung myeloperoxidase levels, and histologic score were significantly reduced when IL-10 was administered either before or after reperfusion. CONCLUSIONS: IL-10 reduced the severity of local and systemic inflammation in a murine model of intestinal I/R when given before or after reperfusion injury. These observations suggest that IL-10 may exert its effect by blocking cytokine production and distant organ neutrophil accumulation.

An ETa/ETb endothelin antagonist ameliorates systemic inflammation in a murine model of acute hemorrhagic pancreatitis.

BACKGROUND: Endothelin peptides are polykines with strong vasoconstrictor properties. We have previously shown that endothelin antagonism (PD145065) reduces the local severity of acute pancreatitis. We now investigated the effect of endothelin antagonism on systemic inflammation in a model of acute hemorrhagic pancreatitis. METHODS: Forty-two mice were divided into four groups. Group 1 was fed standard food plus PD145065 every 8 hours. Group 2 was fed a choline-deficient ethionine (CDE) supplemented diet and given saline every 8 hours. Group 3 was fed a CDE diet and treated with PD145065 every 8 hours from initiation of diet. Group 4 was fed a CDE diet and given PD145065 from 48 hours after initiation of diet. Animals were killed at 70 hours. Serum was collected. Pancreata and lung tissue were harvested. RESULTS: Histology score, serum amylase level, lung myeloperoxidase, and interleukin (IL)-10 were all significantly reduced in both treatment groups (groups 3 and 4) (p < 0.05). IL-6 levels were reduced in group 3 only (p < 0.05). The mortality rate did not differ among any of the groups. CONCLUSIONS: Endothelin antagonism decreased the severity of acute pancreatitis and reduced markers of systemic inflammation. Late treatment at 48 hours failed to prevent the rise in IL-6. Mortality rates were unaffected by treatment.

Perfluoro-n-decanoic acid: induction of peroxisomal beta-oxidation by a fatty acid with dioxin-like toxicity.

Perfluoro-n-decanoic acid (PFDA) produces toxic effects in rodents similar to those caused by 2,3,7,8-tetrachloro-dibenzo-p-dioxin. A single, intraperitoneal dose (50 mg/kg) of PFDA to Sprague-Dawley rats caused disruption of the endoplasmic reticulum, mitochondrial swelling and increases in intracellular lipid droplets in hepatocytes similar to effects reported previously in dioxin toxicity. PFDA treatment led to large decreases in the activity of plasma membrane alkaline phosphodiesterase and mitochondrial cytochrome c oxidase without affecting lysosomal N-acetyl-beta-glucosaminidase, endoplasmic reticulum NADPH-cytochrome c reductase or peroxisomal catalase activities. PFDA treatment led to moderate peroxisome proliferation and to very large (20-40-fold) increases in the activity of fatty acyl-CoA oxidase, the rate-limiting enzyme in the peroxisomal system of fatty acid beta-oxidation.