Gastric restrictive procedures to treat obesity: reasons for failure and long-term evaluation of the results of operative revision.

BACKGROUND AND OBJECTIVE: Bariatric surgery has included a large number of operative procedures, some of which have become extinct and others, such as gastric restrictive procedures, which continue to be performed. While these operative procedures play an important role in the management of obesity, they are associated with significant failure rates. This study was performed to evaluate the results of operations performed on patients to revise failed gastric restrictive procedures. METHODS: During the past 15 years operative revision of gastric restrictive procedures was performed on 65 patients. The demographic, operative, and postoperative information has been prospectively collected. The patients were divided into 20 non-obese patients who weighed less than 250 pounds (range 90-247 pounds) and 45 obese patients weighing more than 250 pounds (range 256-527 pounds). The primary indications for operation on the non-obese patients were intragastric foreign body, gastric fistula, gastroesophageal reflux, and non emptying gastric pouch. The obese patients underwent revision for gastroesophageal reflux and failure to maintain weight loss. The obese patients frequently had obesity associated health problems including sleep apnea (N = 5), hypertension (N = 6), diabetes (N = 5) and ventral hernia (N = 30). The operative procedures in the non-obese patients consisted of revision of a gastroplasty in two patients, conversion of a gastroplasty to a gastric bypass in 12 patients and revision of a gastric bypass in eight patients. In the obese patient group, eight patients underwent revision of a gastroplasty, 19 patients had a gastroplasty converted to a gastric bypass and 14 patients underwent revision of a gastric bypass. The mean +/- SEM length of follow-up was 57 +/- 8 months. RESULTS: There were two postoperative deaths, one from a pulmonary embolus and one from unknown cause. There was no significant difference regarding the results of the various operations to revise gastric restrictive procedures on the weight of the non-obese patients at long-term follow-up. When obese patients underwent revision of a gastric bypass procedure, they lost 69 +/- 9 pounds which was significantly less than the 82 +/- 12 pounds lost by the patients who underwent revision of a gastroplasty. Conversion of gastroplasty operations to gastric bypass operations in obese patients resulted in the loss of 110 +/- 7 pounds at long-term follow-up. CONCLUSIONS: Revision of gastric restrictive procedures can be performed with durable control of obesity; however, revision of gastric bypass restrictive procedures in obese patients produced the least benefit.

Idiopathic megarectum complicating pregnancy: report of a case.

Pregnancy often exacerbates constipation in young women with chronic constipation syndromes. The presence of the fetus presents a challenge in both the diagnosis and treatment of these syndromes. This study was conducted to report a rare case of idiopathic megarectum complicating a pregnancy. An aggressive polyethylene glycol (PEG) regimen allowed the patient to carry the child to term and to have a normal vaginal delivery. Successful proctocolectomy was performed with coloanal anastomosis 3 months postpartum. The patient has been free of constipation for 18 months without the need for cathartics or laxatives. All efforts to avoid operative intervention should be made in constipated patients during pregnancy. This principle holds true even in the setting of dilated large bowel. Idiopathic megarectum and the management of constipation in pregnancy are discussed.

Clostridium difficile toxins influence hepatocyte protein synthesis through the interleukin 1 receptor.

HYPOTHESIS: Clostridium difficile toxins require interleukin 1 (IL-1) production or a functioning IL-1 receptor to elicit acute-phase protein production by murine hepatocytes. DESIGN: Experimental study. SETTING: Research laboratory at the DVA Medical Center, St Louis, Mo. CELLS STUDIED: Hepatocytes prepared from normal mice, from knockout mice deficient in IL-1 production due to loss of IL-1 converting enzyme, or from knockout mice deficient in the IL-1 p80 receptor. INTERVENTIONS: Cells were treated with lipopolysaccharide, a crude C difficile toxin extract, or purified C difficile toxins A or B for 24 hours in vitro, then radiolabeled with (35)S methionine. Newly synthesized acute-phase proteins were identified by electrophoresis and autoradiography. MAIN OUTCOME MEASURES: Synthesis of a 23-kd acute-phase protein in response to the various stimuli. RESULTS: Lipopolysaccharide, C difficile culture extract, and purified toxins A and B stimulated the synthesis of the 23-kd acute-phase protein by hepatocytes from normal mice and by hepatocytes from knockout mice deficient in the IL-1 converting enzyme. However, hepatocytes from knockout mice deficient in the IL-1 p80 receptor failed to produce this acute-phase protein when treated with the C difficile toxins, although they responded fully to lipopolysaccharide. CONCLUSIONS: Stimulation of acute-phase protein synthesis by C difficile toxins does not require IL-1 production, but does require a functioning IL-1 p80 receptor. This suggests that some of the actions of these toxins are mediated by this receptor.

The role of cyclooxygenase enzymes in the growth of human gall bladder cancer cells.

Information suggests that the cyclooxygenase (COX) metabolites, the prostanoids, play a role in gall bladder physiology and disease. Non-steroidal anti-inflammatory drugs which inhibit COX enzymes have been shown in vivo and in vitro to alter the growth patterns of intestinal epithelial cells, and specific COX-2 inhibitors have been shown to decrease mitogenesis in intestinal epithelial cells. The present study was intended to evaluate the effect of specific COX inhibitors on the growth patterns of gall bladder cancer cells. Employing a human gall bladder cancer cell line, mitogenesis, apoptosis and prostaglandin E(2) (PGE(2)) formation were evaluated in response to serum and hepatocyte growth factor and transforming growth factor alpha stimulation in the presence and absence of specific COX-1 and -2 inhibitors. The effect of the mitogens on COX enzyme expression was also evaluated. Serum and the growth factors increased COX enzyme expression and mitogenesis, and decreased apoptosis as evaluated by the percentage of cells that were floating in culture media rather than attached. There was more DNA degradation in floating than in attached cells. The specific COX-2 inhibitor, but not the COX-1 inhibitor, decreased mitogenesis and increased gall bladder cell apoptosis as evaluated by the number of floating versus attached cells and the number of floating cells in the terminal phase of apoptosis or dead. The inhibition of mitogenesis and the increased apoptosis produced by the COX-2 inhibitor was associated with decreased PGE(2) production. The inhibition of replication of gall bladder cancer cells and the increase in apoptosis produced by the selective COX-2 inhibitor suggests that the COX enzymes and the prostanoids may play a role in the development of gall bladder cancer and that the COX-2 inhibitors may have a therapeutic role in the prevention of gall bladder neoplasms.

2,3,7,8 Tetrachlorodibenzo-p-dioxin induction of cytochrome P4501A in cultured rat and human hepatocytes.

We report here a novel observation that 2,3,7,8-tetracholorodibenzo-p-dioxin (TCDD) induced predominantly cytochrome P4501A1 (CYP1A1) in rat hepatocytes and predominantly CYP1A2 in human hepatocytes. As part of our research program to evaluate species-differences in response to CYP inducers, we studied the effects of TCDD on CYP1A activity, protein, and gene expression in primary cultures of rat and human hepatocytes. TCDD was found to induce CYP1A activity, measured as ethoxyresorufin-O-deethylase (EROD) activity, in both rat and human hepatocytes. TCDD induction of EROD activity in human hepatocytes (2-5 fold of concurrent solvent control), was significantly lower than that found in rat hepatocytes ( 20-fold of concurrent solvent control). Two structural analogs of TCDD, 2,3,7,8-tetrachlorodibenzofuran (TCDF) and 6-nitro-1,3,8-trichlorodibenzofuran (6-NCDF), were also evaluated. As observed for TCDD, human hepatocytes consistently showed a lower response than rat hepatocytes. As most TCDD-related effects are believed to be mediated via binding of the TCDD-Ah receptor (AhR) complex to DNA, nuclear AhR levels were measured in rat and human hepatocytes after TCDD treatment. We found that the nuclear AhR levels in TCDD-treated rat hepatocytes were approximately 4 times higher than found in TCDD-treated human hepatocytes. However, the estimated binding affinity of [3H]TCDD to nuclear AhR from rat hepatocytes was similar. The species difference in response to TCDD was further evaluated by analysis of CYP1A1 and CYP1A2 mRNA levels using Northern analysis, and P4501A1 and 1A2 protein levels using Western immunoblotting. Results showed that, at both gene expression and protein levels, TCDD induced predominantly CYP1A1 in rat hepatocytes and CYP1A2 in human hepatocytes.

Role of cytosolic phospholipase A2 in cytokine-stimulated prostaglandin release by human gallbladder cells.

Eicosanoids are involved in gallbladder inflammation, epithelial water transport, and mucous secretion. Phospholipase Asubscript2 enzymes liberate arachidonic acid from membrane phospholipids for the synthesis of eicosanoids. The purpose of this study was to determine the effect of selective cytoplasmic and secretory phospholipase A2 inhibitors on basal and stimulated arachidonic acid and prostaglandin E2 release in gallbladder cells. Western immunoblotting was employed to evaluate both cytosolic and secretory phospholipase A2 enzymes in human gallbladder cells. Cells were incubated for 22 hours with (3)H-labeled arachidonic acid. Arachidonic acid and prostaglandin E2 release was then measured in the supernate after 2 hours of exposure to human interleukin-1beta, alone or after pretreatment for 1 hour with the inhibitors. Unstimulated gallbladder cells express both 85 kDa cytosolic and 14 kDa secretory phospholipase A2++. The 85 kDa phospholipase A2 was induced by interleukin-1beta, whereas there was no apparent change in secretory phospholipase A2 enzyme concentrations. Both the secretory phospholipase A2 inhibitor p-bromophenylacyl bromide and the cytosolic phospholipase A2 inhibitor arachidonyl trifluoromethyl ketone decreased basal and interleukin-1beta-stimulated arachidonic acid release. In contrast, only inhibition of cytosolic phospholipase A2 led to a decrease in interleukin-1beta-stimulated prostaglandin E2 release. Basal and interleukin-1beta-stimulated arachidonic acid release appears to be the result of the activity of both cytosolic and secretory phospholipase A2. Interleukin-1beta-stimulated prostaglandin E2 release appears to be dependent on the activity of cytosolic phospholipase A2.

Clostridium difficile toxin: cytoskeletal changes and lactate dehydrogenase release in hepatocytes.

BACKGROUND: We have found that Clostridium difficile toxins can evoke hepatocyte acute-phase protein synthesis, and that this effect is dependent on a functioning interleukin-1 (IL-1) receptor. The present study was undertaken to determine if C. difficile toxicity, as determined by actin rearrangement and lactate dehydrogenase (LDH) release, also requires a functioning IL-1 receptor. METHODS: Primary hepatocyte cultures were prepared from normal mice, knockout mice deficient in the IL-1-converting enzyme (ICE), and knockout mice deficient in the IL-1 p80 receptor. Hepatocytes were treated for 24 h with C. difficile culture extract, purified C. difficile toxin A, or purified C. difficile toxin B. The actin cytoskeleton was examined using confocal microscopy, and LDH release was measured by spectrophotometric analysis. RESULTS: C. difficile culture extract, toxin A, and toxin B induced collapse of the actin cytoskeleton in hepatocytes from normal mice. Hepatocytes from both the ICE-deficient mice and the IL-1 p80 receptor-deficient mice demonstrated similar responses to both toxins. These toxins also induced significant LDH release in a concentration-dependent fashion in the normal hepatocytes and the ICE-deficient hepatocytes. However, no significant increase in LDH release was observed in hepatocytes from IL-1 p80 receptor-deficient mice. CONCLUSIONS: C. difficile toxins induce actin cytoskeletal collapse independent of IL-1 or the IL-1 receptor. In contrast, toxin-stimulated LDH release was dependent on the presence of the IL-1 receptor. Thus, separate pathways appear to mediate toxic effects as manifested by actin rearrangement and LDH release.

The role of gastric restrictive procedures in treating ventral hernias in morbidly obese patients.

INTRODUCTION: Ventral hernia repair in severely obese patients represents a therapeutic challenge associated with the potential of recurrence. It was our intention in the management of patients with symptomatic ventral hernias in the presence of severe obesity to ascertain the role of weight loss produced by a gastric restrictive procedure (GRP) in the management of the hernias. METHODS: Thirty-three patients underwent ventral hernia repair and a primary GRP while 37 patients underwent ventral hernia repair and revision of a failed GRP associated with unsatisfactory weight loss. Patients were followed to ascertain the effect of the GRP on body weight and the incidence of recurrent hernia. RESULTS: The mean +/- SEM weight in the patients undergoing primary GRPs and ventral hernia repair was 378 +/- 13 lbs (range 604 to 299 lbs) and the weight of the patients undergoing revision of GRPs and ventral hernia repair was 309 +/- 12 lbs (range 505 to 240 lbs). Mean length of follow-up was 79 +/- 18 months (range 180 to 11 months). Mean +/- SEM weight loss following the primary GRP or the GRP revision was 157 +/- 28 lbs (range 82 to 294 lbs). Repair of recurrent ventral hernia was required following stabilization of weight loss in 11 patients (16%). Long term evaluation of all patients following weight loss identified a 5% incidence of recurrent ventral hernia in those patients who had a body weight less than 200 lbs compared to a 19% incidence of recurrent ventral hernia in patients who weighed between 200 and 250 lbs. Patients who stabilized with a body weight greater than 250 lbs had a ventral hernia recurrence rate of 33%. CONCLUSION: GRPs have the potential to decrease body weight and contribute to the control of ventral hernias; however, it appears to be necessary to reach a body weight of less than 200 lbs to significantly decrease recurrent hernia formation.

Role of cytoplasmic and secretory phospholipase A2 in intestinal epithelial cell prostaglandin E2 formation.

BACKGROUND: Prostanoid production is dependent on the enzymatic activity of phospholipase A2 enzymes to produce the precursor, arachidonic acid. Two principle phospholipase A2 enzymes play a major role in arachidonic acid production, 85kDa cytoplasmic phospholipase A2 (cPLA2) and 14kDa secretory phospholipase A2 (sPLA2). The purpose of this study was to determine the PLA2 enzyme involved in prostanoid formation in intestinal epithelial cells. METHODS: Employing a human and murine intestinal epithelial cell line, cells were exposed to the stimulants lipopolysaccharide (LPS), interleukin 1beta (IL-1) and calcium ionophore (Ca Ion) in the presence and absence of cPLA2 and sPLA2 inhibitors. The expression of both PLA2 enzymes and prostaglandin E2 (PGE2) formation were determined. RESULTS: Western blotting demonstrated that the cPLA2 enzyme was constitutively expressed in the human cell lines and not evidently increased by exposure to any of the stimulants. In murine cells the cPLA2 enzyme was also constitutively expressed and not induced by the stimulants evaluated. The sPLA2 enzyme was constitutively expressed in both cell lines and appeared to be induced by LPS and IL-1 in human enterocytes but not by Ca Ion. In murine enterocytes sPLA2 was induced by all three stimuli. PGE2 production by the human cell line was increased by LPS, IL-1 and Ca Ion. IL-1 and Ca Ion stimulated PGE2 formation was inhibited by the cPLA2 enzyme inhibitors while LPS stimulated PGE2 production was not inhibited by the cPLA2 inhibitor; but was inhibited by the sPLA2 enzyme inhibitor. Murine epithelial cells increased PGE2 formation in response to IL-1 and Ca Ion, but not LPS and the increased PGE2 was significantly decreased by cPLA2 enzyme inhibitors. CONCLUSIONS: The metabolic pathway of PGE2 formation is variable and the PLA2 enzyme involved in producing PGE2 is dependent on the stimulus and the cell line. In human intestinal epithelial cells, LPS production of PGE2 proceeds through a pathway associated with sPLA2 generated arachidonic acid while IL-1 stimulated PGE2 is produced by arachidonic acid generated by cPLA2. The physiologic significance of the various metabolic pathways of PGE2 formation is unknown.

The effect of phospholipase A2 inhibitors on proliferation and apoptosis of murine intestinal cells.

BACKGROUND: Group II phospholipase A2 (PLA2) enzymes, the rate controlling enzymes in arachidonic acid metabolism, have been well characterized and subdivided into secretory 14-kDa PLA2 (sPLA2) and cytoplasmic 85-kDa PLA2 (cPLA2). Previous research has demonstrated increased PLA2 in colorectal tumors. The present study was performed to determine the effect of specific PLA2 inhibitors on the proliferation and induction of apoptosis of intestinal epithelial cells. METHODS: A continuously proliferating rat small intestinal cell line (IEC-18) and a mouse colon cancer cell line (WB-2054-M4) were utilized for these experiments. The cells were placed in microwells with serum-free or serum-supplemented media. The effects of serum on proliferation were then evaluated in the presence of the cPLA2 inhibitor, methylarachidonyl fluorophosphate (MAFP), or the sPLA2 inhibitor p-bromophenacyl bromide (BPB). The sPLA2 and cPLA2 protein was estimated by Western blotting. Proliferation of intestinal cells was quantitated by incorporation of [3H]thymidine into DNA and PLA2 activity was evaluated by quantitating arachidonic acid formation and prostaglandin E2 production. RESULTS: Western blotting of IEC-18 and WB-2054 cell protein demonstrated sPLA2 and cPLA2 enzyme in cells incubated in media containing 10% serum. Spontaneous DNA synthesis was present in both cell lines and serum consistently increased proliferation. In IEC-18 cells [3H]thymidine incorporation stimulated by serum was inhibited by MAFP and BPB, while in the malignant cell line, proliferation was inhibited only by BPB. BPB, but not MAFP, produced a dose-dependent increase in apoptotic ratios in both cell lines. Arachidonic acid and PGE2 formation, stimulated by serum, was inhibited by MAFP and BPB. CONCLUSIONS: A differential effect on intestinal cell mitogenesis was seen with different PLA2 inhibitors. The sPLA2 inhibitor, but not the cPLA2 inhibitor, significantly inhibited [3H]thymidine incorporation in the malignant cell line. This occurred with an induction of apoptosis. sPLA2 inhibitors may be specific inhibitors of growth of malignant cells. The inhibition of arachidonic acid and PGE2 production did not correlate with the inhibition of proliferation, suggesting that the two processes may be unrelated.

The effect of selective cyclooxygenase inhibitors on intestinal epithelial cell mitogenesis.

INTRODUCTION: Previous research has demonstrated that nonsteroidal anti-inflammatory agents alter the incidence of colorectal cancer. It has been postulated that the response may be due to the effect of these agents on the activities of the cyclooxygenase (COX) enzymes. The COX enzymes catalyze the conversion of arachidonic acid to biologically active prostanoids. Two forms of COX have been identified. COX-1 is a constitutive enzyme, generally involved in cell functions, while COX-2 is commonly an enzyme which is inducible in response to various stimuli, including mitogens. Recently, specific inhibitors of COX-1 and COX-2 enzymes have been developed. PURPOSE: The present study was undertaken to determine the effects of specific COX-1 and COX-2 inhibitors on the proliferation and the induction of apoptosis of intestinal epithelial cells. METHODS: A continuously proliferating rat small intestinal cell line (IEC-18) and a mouse colon cancer cell line (WB-2054) were utilized for these experiments. The cells were placed in microwells with serum-free or serum-supplemented media. The effects of serum on proliferation were then evaluated in the presence of the COX-1 inhibitor, valerylsalicyclic acid (VSA), the COX-2 inhibitor, SC-58125, or indomethacin. The presence of COX-1 and COX-2 protein was evaluated by Western blotting. Proliferation of intestinal cells was quantitated by incorporation of [3H]thymidine into DNA and cell counting, and apoptosis was determined by evaluating cell attachment. COX activity was evaluated by prostaglandin E2 production measured by enzyme-linked immunoabsorbent assay (ELISA). RESULTS: Western blotting of IEC-18 and WB-2054 cell protein demonstrated COX-1 enzyme in cells incubated in serum-free media with increased COX-1 expression produced by incubation in media supplemented with 10% serum. COX-2 enzyme was not demonstrated in serum-free media; however, it was present in cells maintained in 10% serum-supplemented media. Spontaneous DNA synthesis was present in both cell lines and serum increased proliferation. In both cell lines [3H]thymidine incorporation stimulated by serum was inhibited by the COX-2 inhibitor SC-58125, but not by the COX-1 inhibitor VSA. Both indomethacin and SC-58125 produced a dose-dependent increase in apoptotic ratios in both cell lines. PGE2 formation, stimulated by serum, was inhibited by SC-58125, VSA, and indomethacin. CONCLUSION: A differential effect on intestinal cell mitogenesis was seen with different COX inhibitors. The COX-2 inhibitor, but not the COX-1 inhibitor, significantly inhibited [3H]thymidine incorporation in both cell types, suggesting COX-2 inhibitors may be specific inhibitors of normal epithelial cell proliferation and growth of malignant cells. SC-58125, a selective inhibitor of COX-2, has a potent apoptosis inducing effect. The inhibition of PGE2 production did not correlate with the inhibition of proliferation, suggesting the two processes are unrelated.

The role of cyclooxygenase-1 and cyclooxygenase-2 in lipopolysaccharide and interleukin-1 stimulated enterocyte prostanoid formation.

Lipopolysaccharide is an inflammatory agent and interleukin-1 is a cytokine. Their pro-inflammatory effects may be mediated by prostanoids produced by inducible cyclooxygenase-2. The aim of this study was to determine the prostanoids produced by lipopolysaccharide and interleukin-1 stimulated enterocytes through the cyclooxygenase-1 and 2 pathways. Cultured enterocytes were stimulated with lipopolysaccharide or interleukin-1beta with and without cyclooxygenase inhibitors. Low concentrations of indomethacin and valerylsalicylic acid (VSA) were evaluated as cyclooxygenase-1 inhibitors and their effects compared with the effects of a specific cyclooxygenase-2 inhibitor, SC-58125. Prostaglandin E2, 6-keto prostaglandin F1alpha, prostaglandin D2 and leukotriene B4 levels were determined by radioimmunoassay. Immunoblot analysis using isoform-specific antibodies showed that the inducible cyclooxygenase enzyme (COX-2) was expressed by 4 h in LPS and IL-1beta treated cells while the constitutive COX-1 remained unaltered in its expression. Interleukin-1beta and lipopolysaccharide stimulated the formation of all prostanoids compared with untreated cells, but failed to stimulate leukotriene B4. Indomethacin at 20 microM concentration, and VSA inhibited lipopolysaccharide and interleukin 1beta stimulated prostaglandin E2, but not 6-keto prostaglandin F1alpha formation. SC-58125 inhibited lipopolysaccharide and interleukin-1beta stimulated 6-keto prostaglandin F1alpha but not prostaglandin E2 release. The specific cyclooxygenase-2 inhibitor also inhibited lipopolysaccharide produced prostaglandin D2 but not interleukin-1beta stimulated prostaglandin D2. While SC-58125 inhibited basal 6-keto prostaglandin-F1alpha formation it significantly increased basal prostaglandin E2 and prostaglandin D2 formation. As SC-58125 inhibited lipopolysaccharide and interleukin-1beta induced 6-keto prostaglandin F1alpha production but not prostaglandin E2 production, it suggests that these agents stimulate prostacyclin production through a cyclooxygenase-2 mediated mechanism and prostaglandin E2 production occurs through a cyclooxygenase-1 mediated mechanism. Prostaglandin D2 production appeared to be variably produced by cyclooxygenase-1 or cyclooxygenase-2, depending on the stimulus.

Evaluation of benzalkonium chloride chemoneurolytic proximal gastric vagotomy.

BACKGROUND: Transmucosal chemoneurolytic injection of benzalkonium chloride (BAC) has previously been shown to duplicate operative proximal gastric vagotomy (PGV) in controlling gastric acid secretion. In this study, BAC was evaluated as to efficacious dose, methods of delivery, and systemic toxicities. METHODS: Sham celiotomy, operative PGV controls, transmucosal injections through a gastrotomy, and transserosal injections of BAC (saline controls, 0. 625, 1.25, 2.5, 5.0, 10 mg BAC/kg body wt) were administered to Sprague-Dawley rats. After 3 months the rats underwent Congo red testing (CRT), horseradish peroxidase (HRP) neuronal staining, and necropsy. The color density change of the gastric mucosa from basic to acidic demonstrated by the CRT at the time of necropsy was used to calculate the residual anatomic acid-secreting area. Prior to necropsy, subserosal HRP injections into the anterior and posterior stomach walls assayed vagal neuronal viability via retrograde axonal flow. Results were compared by an ANOVA. RESULTS: The results demonstrated that 1.25-10 mg/kg transmucosal BAC replicated the results of operative PGV; 2.5 mg/kg was found to be the most effective dose. All injection groups including saline controls demonstrated similar diminished vagal retrograde axonal flow by HRP testing consistent with local BAC chemoneurolytic effects. No systemic toxic symptoms were observed after tail vein intravenous BAC 1.25, 2.5, and 5.0 mg/kg. CONCLUSIONS: These efficacy studies have demonstrated BAC's potential utility in the performance of endoscopic transmucosal chemoneurolytic PGV.

Management and outcome of patients with combined bile duct and hepatic artery injuries.

BACKGROUND: Major bile duct injury is an important therapeutic problem that can be associated with simultaneous injury to the hepatic artery. Limited information exists regarding the course of patients who have combined bile duct and arterial injuries. OBJECTIVE: To compare the management and outcome of isolated bile duct injuries with bile duct and hepatic artery injuries. PATIENTS AND METHODS: Since 1991, 13 patients have undergone reconstruction of right and left hepatic confluence or proximal bile duct injuries. At the time of bile duct injury, 4 of these patients had simultaneous occlusion or extirpation of the right hepatic or common hepatic artery. All patients underwent reconstruction of the biliary tract with hepaticojejunostomies. The immediate and long-term outcomes of the patients with and without hepatic artery injury were compared. RESULTS: In the immediate postoperative period, 3 of 4 patients with combined injuries had hepatic necrosis and/or abscesses with 2 patients requiring transcutaneous or operative drainage. This problem was not diagnosed in patients with isolated bile duct injuries. None of the biliary anastomoses have failed in the patients with isolated bile duct injuries while 50% of the anastomoses in patients with combined injuries have caused recurrent problems following reconstruction. CONCLUSION: Patients with major bile duct injuries should be evaluated for concomitant hepatic arterial injury as management and outcome may be influenced by the absence of arterial blood flow to the injured bile ducts and to the liver.

Contribution of cyclooxygenase-1 and cyclooxygenase-2 to prostanoid formation by human enterocytes stimulated by calcium ionophore and inflammatory agents.

The stimulation of intestinal epithelial cell cyclooxygenase (COX) enzymes with inflammatory agents and the inhibition of COX-1 and COX-2 enzymes has the potential to increase understanding of the role of these enzymes in intestinal inflammation. The aim of this study was to determine the contributions of COX-1 and -2 to the production of specific prostanoids by unstimulated and stimulated intestinal epithelial cells. Cultured enterocytes were stimulated with lipopolysaccharide (LPS), interleukin-1 (IL-1)beta (IL-1 beta), and calcium ionophore (Ca Ion), with and without COX inhibitors. Valerylsalicylic acid (VSA) was employed as the COX-1 inhibitor, and SC-58125 and NS398 were used as the COX-2 inhibitors. Prostanoids were quantitated by Elisa assay. Western immunoblotting demonstrated the presence of constitutive COX-1 and inducible COX-2 enzyme. Unstimulated prostanoid formation was not decreased by the COX-1 inhibitor. All of the stimulants evaluated increased prostaglandin E2 (PGE2) production. Only Ca Ion stimulated prostaglandin D2 (PGD2) production while IL-1 beta, and Ca Ion, but not LPS, increased prostaglandin F2 alpha (PGF2 alpha) formation. Ca Ion-stimulated prostanoid formation was uniformly inhibited by COX-2, but not COX-1, inhibitors. IL-1 beta-stimulated PGE2 and PGE2 alpha formation was significantly decreased by both COX-1 and COX-2 inhibitors. VSA, in a dose-dependent manner, significantly decreased IL-1 beta-stimulated PGE2 and PGF2 alpha production. Unstimulated prostanoid formation was not dependent on constitutive COX-1 activity. The stimulation of intestinal epithelial cells by Ca Ion seemed to uniformly produce prostanoids through COX-2 activity. There was no uniform COX-1 or COX-2 pathway for PGE and PGF2 alpha formation stimulated by the inflammatory agents, suggesting that employing either a COX-1 or COX-2 inhibitor therapeutically will have varying effects on intestinal epithelial cells dependent on the prostanoid species and the inflammatory stimulus involved.

The role of selective cyclooxygenase isoforms in human intestinal smooth muscle cell stimulated prostanoid formation and proliferation.

Intestinal smooth muscle plays a major role in the repair of injured intestine and contributes to the prostanoid pool during intestinal inflammatory states. Cyclooxygenase (COX), which catalyzes the conversion of arachidonic acid to prostanoids exists in two isoforms, COX-1 and COX-2. The purpose of this study was to determine the relative contributions of COX-1 and COX-2 in the production of prostanoids by human intestinal smooth muscle (HISM) cells when stimulated by interleukin-1beta (IL-1beta) and lipopolysaccharide (LPS). Furthermore the effects of specific COX-1 and COX-2 inhibitors on the proliferation of smooth muscle cells was also evaluated. Confluent monolayer cultures of HISM cells were incubated with IL-1beta or LPS for 0-24h while control cells received medium alone. PGE2 and PGI2 as 6-keto-PGF1alpha and LTB4 were measured by a specific radioimmunoassay. COX enzymes were evaluated by Western immunoblotting. Unstimulated and stimulated cells were exposed to the specific COX-1 inhibitor valerylsalicylic acid (VSA) and the COX-2 inhibitors NS-398 and SC-58125. The effects of serum on proliferation were then evaluated in the presence of each of the specific COX inhibitors by incorporation of 3H-thymidine into DNA. IL-1beta and LPS increased both PGE2 and 6-keto-PGF1alpha in a dose dependent fashion with enhanced production detected two hours following exposure. Neither stimulus stimulated LTB4 release. Immunoblot analysis using isoform-specific antibodies showed that both COX-1 and COX-2 were present constitutively. Furthermore, COX-1 was upregulated by each inflammatory stimulus. In a separate set of experiments cells were pretreated with either the selective COX-1 inhibitor VSA or the selective COX-2 inhibitors NS-398 or SC-58125 prior to treatment with IL-1beta or LPS. The COX-1 and COX-2 inhibitors decreased both basal and IL-1beta and LPS stimulated prostanoid release. Spontaneous DNA synthesis was present and serum consistently increased proliferation. 3H-thymidine incorporation, stimulated by serum, was inhibited by both COX-1 and COX-2 inhibitors. This study suggests that the prostanoid response stimulated by proinflammatory agents of gut-derived smooth muscle cells appears to be mediated by both COX-1 and COX-2 enzymes. Proliferation of smooth muscles cells also appears to be influenced by both COX-1 and COX-2.

Primary human hepatocytes as a tool for the evaluation of structure-activity relationship in cytochrome P450 induction potential of xenobiotics: evaluation of rifampin, rifapentine and rifabutin.

In our laboratory, primary human hepatocytes are being investigated as an in vitro experimental system for the evaluation of pharmacokinetic drug-drug interactions. Our study here represents the first reported study that directly compares the cytochrome P450 isozyme 3A (CYP3A) induction potential of three antimicrobials derived from rifamycin B, namely, rifampin, rifapentine and rifabutin. Two endpoints of CYP3A activity, testosterone 6 beta-hydroxylation and midazolam 1-hydroxylation have been used. Results obtained with hepatocytes from four different human donors show consistently that rifampin and rifapentine are potent inducers of CYP3A, while a significantly lower induction potential is observed for rifabutin. The relative induction potency of the three antimicrobials (rifampin > rifapentine >> rifabutin) is consistent with the available human in vivo data. For CYP1A measured as ethoxyresorufin O-deethylase activity, CYP2C8/9 measured as tolbutamide 4-hydroxylation activity, CYP2D6 measured as dextromethorphan O-demethylation, and AZT glucuronidation, there is either no effect or, where induction is found to be statistically significant in these other endpoints, the maximum induction values are consistently < 100% of the control. Our results suggest that CYP3A is the major CYP induced by these rifamycin B derivatives. These studies illustrate the application of human hepatocytes in the evaluation of the structure-activity relationships in CYP induction for this class of chemicals and as an in vitro screen for drug-drug interaction potential via CYP induction.

Prospective evaluation of a new through-the-scope nasoduodenal enteral feeding tube.

BACKGROUND: With present techniques, transpyloric feeding tube placement is unreliable. This study evaluated a new nasoduodenal tube placed through a gastroscope. METHODS: A therapeutic gastroscope was advanced into the distal duodenum, and through the 3.7-mm channel this feeding tube was advanced under direct vision into the small bowel. The tube/guidewire combination was then advanced with the concomitant equidistant retraction of the scope until the wire could be grasped at the lips and exchanged to the nose using a nasal transfer tube. The guidewire was removed, and a "Y" connector was then attached to the end of the tube. RESULTS: Successful tube placement in all 21 patients (14M/7F) required an endoscopy time of 31 +/- 3.3 min and the tubes were utilized for 9.24 +/- 0.94 days. Tube tips were confirmed in the distal duodenum (10) or proximal jejunum (11) by radiographic contrast injection. CONCLUSION: This new through-the-scope tube can be placed in the distal duodenum quickly, safely, and consistently.

The effect of trinitrobenzene sulfonic acid on gut-derived smooth muscle cell arachidonic acid metabolism: role of endogenous prostanoids.

The contribution of smooth muscle cells as a potential source of eicosanoid production during inflammatory states remains to be elucidated. We investigated the effect of trinitrobenzene sulfonic acid (TNB), a known pro-inflammatory agent, on jejunal smooth muscle cell eicosanoid production. Human gut-derived smooth muscle cells (HISM) were incubated with TNB for 1 hour. Additionally, some cells were preincubated with either dimethylthiourea, or indomethacin for 1 hour before exposure to identical concentrations of TNB. Incubation with TNB led to significant increases in PGE(2) and 6-keto PGF-1(alpha) release, but not leukotriene B(4) release; responses which were both inhibited by dimethylthiourea and indomethacin treatment. Our results suggest that gutderived smooth muscle cells may represent an important source of proinflammatory prostanoids but not leukotrienes during inflammatory states of the intestine. The inhibition of prostanoid activity by thiourea may be mediated by suppression of cyclooxygenase activity in this cell line.

Outcome of patients with total colonic ischemia.

PURPOSE: In this study, we sought to determine the outcome of patients with ischemic colitis, comparing patients with segmental disease with those with total colonic ischemia. METHODS: Patients with the diagnosis of ischemic colitis over the past six years were selected and reviewed for demographics, presenting symptoms, diagnosis, and treatment. RESULTS: Forty-three consecutive patients with ischemic colitis were identified and were grouped into those with segmental ischemic colitis and total colonic ischemia. Mean age was 68.8 years; 28 of 43 patients (65 percent) were males. Diagnosis was established by colonoscopy in 31 of 43 patients (72 percent), whereas in the remainder, diagnosis was made in the operating room. Ischemic colitis developed in the hospital in 17 of 43 patients (40 percent) during admission for an unrelated illness. In 6 of 43 (14 percent) of these patients, ischemic colitis developed following surgery. Thirty-one of 43 patients (72 percent) were found to have segmental colitis; 11 of 31 patients (35 percent) were successfully managed nonoperatively. Segmental colitis was present in 31 of 43 patients (72 percent), and 12 of 31 (35 percent) of these patients were successfully managed nonoperatively. In the patients with segmental colitis who required surgery, the 30-day mortality rate was 22 percent. Among 12 of 17 patients (71 percent) with segmental ischemia treated by resection and stoma, 9 of 12 (75 percent) underwent eventual stoma closure. All 12 patients with total colonic ischemia required surgery, and 9 of 12 patients (75 percent) died. CONCLUSION: Ischemic colitis occurs commonly during an unrelated hospital admission and following previous surgery. Most patients treated by resection and stoma undergo stoma closure. Total colonic ischemia carries a worse prognosis than segmental colonic ischemia.