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1.
Br J Surg ; 96(6): 641-9, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19434658

ABSTRACT

BACKGROUND: Pancreatic fistula is traditionally suspected on the basis of increased drain amylase activity. However, some patients have a low amylase level but later manifest clinical evidence of a fistula. This study investigated the prevalence and significance of these presentations. METHODS: Severity of fistula was determined according to the International Study Group on Pancreatic Fistula criteria for 405 consecutive pancreatic resections. Latent fistulas, initially lacking amylase-rich effluent but ultimately clinically relevant (grades B or C), were examined to determine their impact and significance. RESULTS: Fistula of any extent occurred in 107 patients (26.4 per cent). Latent fistulas occurred in 20 patients (4.9 per cent of all resections, 18.7 per cent of all fistulas and 36 per cent of all clinically relevant fistulas). Initial amylase activity was consistently low (range 3-235 units/l), but these fistulas subsequently manifested clinical relevance (abdominal pain, radiographic evidence, fever, sinister effluent, wound infection). Latent presentations had twice the infection rate of evident fistulas, required more aggressive interventions, resulted in longer hospitalizations and incurred greater hospital costs. CONCLUSION: A considerable proportion of patients with pancreatic fistula do not initially demonstrate an amylase-rich effluent. These patients have significantly worse outcomes. In fistula definition, the clinical course is important as well as biochemical parameters.


Subject(s)
Amylases/metabolism , Pancreatectomy/adverse effects , Pancreatic Fistula/enzymology , Pancreatic Neoplasms/surgery , Postoperative Complications/enzymology , Cohort Studies , Drainage , Humans , Length of Stay , Pancreatic Fistula/classification , Pancreatic Fistula/etiology , Pancreatic Neoplasms/enzymology , Postoperative Complications/etiology , Risk Factors , Severity of Illness Index , Treatment Outcome
2.
Surg Endosc ; 20(11): 1654-8, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17063288

ABSTRACT

Experience alone is not sufficient to protect surgeons and their patients from biliary injury. This article suggests valuable technical considerations for the performance of laparoscopic cholecystectomy. Against the background of a widely accepted biliary injury classification system, the risk factors and causes of biliary injury are considered. The concept of the critical view exposure technique for Calot's triangle is emphasized from the practical standpoint of avoiding misidentified injuries.


Subject(s)
Bile Duct Diseases/prevention & control , Bile Ducts/injuries , Cholecystectomy, Laparoscopic/adverse effects , Intraoperative Complications/prevention & control , Bile Duct Diseases/etiology , Blood Vessels/injuries , Cholecystectomy, Laparoscopic/methods , Humans , Risk Factors
3.
Surg Endosc ; 18(10): 1411-9, 2004 Oct.
Article in English | MEDLINE | ID: mdl-15791361

ABSTRACT

The trauma of surgery evokes a variety of physiologic and immunologic alterations that should contribute to host defense. However, an exaggerated response to injury may result in immunosuppression and lead to significant postoperative morbidity and mortality. Laparoscopic surgery may result in less induced surgical trauma than conventional open surgery. Decreased postoperative pain and speedy functional recovery of laparoscopic patients may be attributable to the reduced inflammatory response and minimal immunosuppression. Inflammation, an early protective homeostatic immune response to injury, is characterized by the production of proinflammatory cytokines and by activation of cellular and humoral immune mechanisms. Postoperative levels of the inflammatory cytokines have been consistently lower after laparoscopic procedures, indicating a smaller degree of surgical insult and acute inflammatory reaction. Surgical stress derails the functions of both polymorphonuclear and mononuclear cells, which may lead to an increased risk of postoperative infection. Comparative studies of cellular immunity after laparoscopic and conventional surgery demonstrate immunologic advantage conferred by laparoscopy. Exaggerated activation of peritoneal immunity may lead to a relative local immunosuppression, resulting in ineffective intraperitoneal bacterial clearance and serious postoperative infections. Functions of the peritoneal macrophages are better preserved when laparotomy is avoided. Decreased perioperative stress may be particularly important for oncologic patients. Laparoscopic approaches may result in diminished perioperative tumor dissemination and better cancer outcomes. Although laparoscopy is "minimally invasive," systemic immune responses still are undeniably activated. However, laparoscopic surgery appears to induce a smaller injury, resulting in proportionally decreased immunologic changes. In addition to improved cosmesis and faster functional recovery, a patient undergoing laparoscopic surgery may benefit most from a net immunologic advantage.


Subject(s)
Laparoscopy , Postoperative Complications/immunology , Animals , Humans , Immunity, Cellular , Peritoneum/immunology , Postoperative Complications/prevention & control
6.
Surg Endosc ; 16(4): 567-71, 2002 Apr.
Article in English | MEDLINE | ID: mdl-11972189

ABSTRACT

BACKGROUND: Gastroesophageal reflux disease (GERD) can be overlooked as the cause of chronic cough (CC) when typical gastrointestinal symptoms are absent or minimal. We analyzed the outcomes of Nissen fundoplication (NF) for patients who failed medical therapy for CC attributable only to GERD (G-CC). We performed a prospective outcome evaluation of 21 consecutive patients with G-CC undergoing NF from 1997 to 2000 at a tertiary care university hospital. MATERIALS AND METHODS: Twenty-one patients without prior antireflux surgeries had G-CC diagnosed by a clinical profile and 24-h pH monitoring showing a cough-reflux correlation. Respiratory symptoms alone were present in 53% of patients. NF was performed when G-CC persisted despite intensive medical therapy, including an antireflux diet. Preoperatively, all patients underwent 24-h pH monitoring, esophageal manometry, barium swallow, gastric emptying study, bronchoscopy, and upper endoscopy. NF was utilized in all cases, laparoscopically in 18. Before and after surgery, patients graded their cough severity using the Adverse Cough Outcome Survey (ACOS). Quality of life was measured using the Sickness Impact Profile (SIP). RESULTS: Postoperatively, 18 patients (86%) reported an improvement of their cough. G-CC considerably improved in 16/21 patients (76%), with complete resolution in 13 patients (62%). Mild to moderate improvement was found in 2 patients (10%). Patient-reported cough severity (ACOS) and quality of life (SIP) both significantly improved early (6-12 weeks) postoperatively and persisted during the long-term (1 year) follow-up. The average hospital length of stay was 1.78 +/- 0.2 (l-4) days for the laparoscopic (n = 18) and 6.3 +/- 1.2 (4-8) days for the open surgery (n = 3) groups. CONCLUSION: Twenty-four-hour esophageal pH monitoring is a valuable tool for preoperative cough-reflux correlation. Antireflux surgery is effective in carefully selected patients whose refractory CC is attributable only to GERD. NF controls the severity of cough while improving the quality of life. Outcomes are further enhanced using laparoscopic procedures with shorter hospital stays.


Subject(s)
Cough/etiology , Cough/surgery , Gastroesophageal Reflux/complications , Gastroesophageal Reflux/surgery , Chronic Disease , Cough/diagnosis , Female , Fundoplication/methods , Gastroesophageal Reflux/diagnosis , Humans , Laparoscopy/methods , Male , Middle Aged , Prospective Studies , Treatment Outcome
7.
Surg Oncol ; 10(1-2): 43-52, 2001.
Article in English | MEDLINE | ID: mdl-11719028

ABSTRACT

The degradation of most eukaryotic cells is controlled by the ubiquitin proteasome pathway. This pathway is responsible not only for the degradation of short and long-lived proteins but also tumor suppressors, transcription factors and cell cycle proteins. Altered degradation of these proteins is thought to promote cancer growth and spread. By contrast, inhibition of the proteasome would lead to cell cycle arrest and ultimately programmed cell death, or apoptosis. A structured review of the published literature examining the role of ubiquitin proteasome inhibition in cancer growth and regulation is provided. Advances in the development of proteasome inhibitors have allowed detailed investigation of this pathway in cancer growth. Relevant in vitro and in vivo studies of proteasome inhibition as pertains to cancer therapy are detailed. The ubiquitin proteasome pathway is critical in the degradation of proteins involved in cell cycle control and tumor growth. Proteasome inhibitors have been shown to arrest or retard cancer progression, by interfering with the ordered, temporal degradation of regulatory molecules. Clinical trials examining the agents have begun.


Subject(s)
Cysteine Endopeptidases/physiology , Cysteine Endopeptidases/therapeutic use , Multienzyme Complexes/physiology , Multienzyme Complexes/therapeutic use , Neoplasms/drug therapy , Neoplasms/physiopathology , Signal Transduction/physiology , Ubiquitin/physiology , Ubiquitin/therapeutic use , Humans , In Vitro Techniques , Multienzyme Complexes/antagonists & inhibitors , Proteasome Endopeptidase Complex , Signal Transduction/drug effects , Ubiquitin/antagonists & inhibitors
8.
Surg Endosc ; 15(7): 729-33, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11591978

ABSTRACT

BACKGROUND: As new techniques are emerging for laparoscopic liver resections, concerns have been raised about the development of gas embolus related to the CO(2) pneumoperitoneum. We hypothesized that elevated intrahepatic vascular pressures and decreased hepatic tissue blood flow (LQB) would prevent gas embolus during laparoscopic liver resections under conventional pneumoperitoneum. METHODS: Intrahepatic vascular pressures and LQB were measured in nine pigs with varying CO(2) pneumoperitoneum. Gas embolus was determined after hepatic incision by monitoring pulmonary arterial pressure (PAP), hepatic venous PCO(2), systemic blood pressure (SBP), and suprahepatic vena cava ultrasound. RESULTS: As the pneumoperitoneum was increased from 0 to 15 mmHg, intrahepatic vascular pressures increased significantly (p < 0.05), while LQB decreased significantly (p < 0.05). A 2.0-cm hepatic incision at 4, 8, 15, and 20mmHg produced no ultrasound evidence of gas embolus and no changes in PAP, SBP, or hepatic venous PCO(2) (p = NS). CONCLUSION: These data suggest that the risk of significant embolus under conventional pneumoperitoneum is minimal during laparoscopic liver resections.


Subject(s)
Embolism, Air/prevention & control , Hepatectomy/methods , Laparoscopy/methods , Pneumoperitoneum, Artificial/methods , Animals , Blood Pressure/drug effects , Blood Pressure/physiology , Carbon Dioxide/administration & dosage , Carbon Dioxide/adverse effects , Embolism, Air/chemically induced , Embolism, Air/etiology , Laparoscopy/adverse effects , Liver/drug effects , Liver/metabolism , Liver Circulation/drug effects , Liver Circulation/physiology , Models, Animal , Pneumoperitoneum, Artificial/adverse effects , Pressure , Swine
9.
Transplantation ; 72(3): 406-12, 2001 Aug 15.
Article in English | MEDLINE | ID: mdl-11502967

ABSTRACT

BACKGROUND: Little data exist regarding the use of ischemic preconditioning before sustained hepatic cold storage. We hypothesized that ischemic preconditioning protects hepatic grafts via a tyrosine kinase-dependent pathway. METHODS: Six porcine livers underwent routine harvest (control). Five other livers underwent 15 min of in situ ischemia followed by 15 min of reflow before harvest (ischemic preconditioning). Another five livers were pretreated with a tyrosine kinase inhibitor (genistein) before preconditioning. Upon reperfusion and after 2 hours of cold storage, graft function, graft circulatory impairment, and markers of cellular damage were analyzed. Tissue cytoplasmic extracts were analyzed for tyrosine phosphorylation with Western blot. Significance was determined with t tests. RESULTS: Ischemic-preconditioned grafts demonstrated enhanced bile production, augmented responses to a bile acid challenge, and elevated O2 consumption (P<0.05) compared to controls. Also, preconditioned grafts demonstrated improved hepatic tissue blood flow and decreased hepatic vascular resistance (P<0.005) compared to controls. Endothelial cell preservation (factor VIII immunostain) was improved in preconditioned graft biopsies compared to controls. With genistein pretreatment, all observed improvements returned to control levels. Analysis of cytoplasmic extracts demonstrated an increase in tyrosine phosphorylation before cold ischemia in preconditioned grafts only, but not in control or genistein-pretreated grafts. CONCLUSIONS: The data indicate that ischemic preconditioning protects the liver from sustained cold ischemia and that tyrosine kinases are involved in preconditioning responses.


Subject(s)
Cryopreservation , Ischemic Preconditioning , Liver Transplantation , Liver/physiopathology , Protein-Tyrosine Kinases/physiology , Alanine Transaminase/metabolism , Animals , Endothelium/pathology , L-Lactate Dehydrogenase/metabolism , Liver/pathology , Phosphorylation , Swine , Tyrosine/metabolism
10.
J Cell Biochem ; 82(1): 110-22, 2001.
Article in English | MEDLINE | ID: mdl-11400168

ABSTRACT

The 26S proteasome degrades proteins that regulate transcription factor activation, cell cycle progression, and apoptosis. In cancer, this may allow for uncontrolled cell division, promoting tumor growth, and spread. We examined whether selective inhibition of the 26S proteasome with PS-341, a dipeptide boronic acid analogue, would block proliferation and induce apoptosis in human pancreatic cancer. Proteasome inhibition significantly blocked mitogen (FCS) induced proliferation of BxPC3 human pancreatic cancer cells in vitro, while arresting cell cycle progression and inducing apoptosis by 24 h. Accumulation of p21(Cip1-Waf-1), a cyclin dependent kinase (CDK) inhibitor normally degraded by the 26S proteasome, occurred by 3 h and correlated with cell cycle arrest. When BxPC3 pancreatic cancer xenografts were established in athymic nu/nu mice, weekly administration of 1 mg/kg PS-341 significantly inhibited tumor growth. Both cellular apoptosis and p21(Cip1-Waf-1) protein levels were increased in PS-341 treated xenografts. Inhibition of tumor xenograft growth was greatest (89%) when PS-341 was combined with the tumoricidal agent CPT-11. Combined CPT-11/PS-341 therapy, but not single agent therapy, yielded highly apoptotic tumors, significantly inhibited tumor cell proliferation, and blocked NF-kappaB activation indicating this systemic therapy was effective at the cancer cell level. 26S proteasome inhibition may represent a new therapeutic approach against this highly resistant and lethal malignancy.


Subject(s)
Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Boronic Acids/pharmacology , Cyclins/drug effects , NF-kappa B/antagonists & inhibitors , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/pathology , Peptide Hydrolases/drug effects , Proteasome Endopeptidase Complex , Pyrazines/pharmacology , Adenocarcinoma/drug therapy , Adenocarcinoma/pathology , Adenocarcinoma/physiopathology , Animals , Antineoplastic Combined Chemotherapy Protocols/pharmacology , Apoptosis/physiology , Boronic Acids/metabolism , Bortezomib , Camptothecin/analogs & derivatives , Camptothecin/pharmacology , Cell Cycle/drug effects , Cell Division/drug effects , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/metabolism , Dipeptides/metabolism , Dipeptides/pharmacology , Drug Resistance, Neoplasm , Humans , Irinotecan , Mice , Mice, Nude , Mitogens/administration & dosage , Pancreatic Neoplasms/physiopathology , Peptide Hydrolases/metabolism , Protease Inhibitors/pharmacology , Pyrazines/metabolism , Tumor Cells, Cultured , Xenograft Model Antitumor Assays/methods
11.
J Surg Res ; 97(2): 123-30, 2001 May 15.
Article in English | MEDLINE | ID: mdl-11341787

ABSTRACT

BACKGROUND: FRAP-p70s6K signaling regulates mitogenic responses to growth factors in eukaryotic cells. Constitutive p70s6K activation occurs in some human malignancies and may contribute to dysregulated cell growth. We examined whether inhibition of this pathway affects mitogen-induced proliferation and cell cycle progression of human pancreatic cancer cells in vitro. METHODS: Quiescent BxPC3 and Panc-1 human pancreatic cancer cells treated with or without 20 ng/mL rapamycin (FRAP inhibitor) were repleted with 10% FCS to induce cell cycle entry. Proliferation was measured with MTT assay. Cell cycle and apoptosis were determined by FACS analysis. Phosphorylation of p70s6K, Akt, and cdc2 was evaluated by Western blot. Statistical analysis was by two-tailed t test (P < 0.05). RESULTS: Rapamycin (Rapa) inhibited the phosphorylation of p70s6K while inducing G(1) cell cycle arrest (P < 0.005). In both cell lines, Rapa inhibited serum-induced proliferation (P < 0.05) without affecting apoptosis. Cdc2 phosphorylation was inhibited by 15 min with Rapa (not shown), consistent with cell cycle arrest. Akt phosphorylation was not affected, indicating FRAP specificity of Rapa. CONCLUSIONS: FRAP-p70s6K signaling appears to be necessary for G(1)-to-S phase progression and proliferation in pancreatic cancer cells. This supports earlier work demonstrating a similar regulatory role for PI-3' kinase, an upstream activator of FRAP-p70s6K.


Subject(s)
Adenocarcinoma , Carrier Proteins , Immunophilins/metabolism , Pancreatic Neoplasms , Phosphotransferases (Alcohol Group Acceptor) , Protein Serine-Threonine Kinases , Ribosomal Protein S6 Kinases/metabolism , Signal Transduction/physiology , Antibiotics, Antineoplastic/pharmacology , CDC2 Protein Kinase/metabolism , Cell Division/drug effects , Cell Division/physiology , Fetal Proteins/pharmacology , Flow Cytometry , G1 Phase/drug effects , G1 Phase/physiology , Humans , Mitogens/pharmacology , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation , Protein Kinases/metabolism , Proto-Oncogene Proteins/metabolism , Proto-Oncogene Proteins c-akt , S Phase/drug effects , S Phase/physiology , Signal Transduction/drug effects , Sirolimus/pharmacology , TOR Serine-Threonine Kinases , Tumor Cells, Cultured/cytology , Tumor Cells, Cultured/enzymology
12.
J Surg Res ; 97(2): 144-9, 2001 May 15.
Article in English | MEDLINE | ID: mdl-11341790

ABSTRACT

INTRODUCTION: A transient period of warm ischemia prior to a longer ischemic episode (ischemic preconditioning) protects the hepatic graft from cold ischemia. The mechanism for this protection is unknown, as is the role of protein kinase C in ischemic preconditioning responses. METHODS: Livers from 40 kg Yorkshire pigs were harvested and subjected to 2 h of cold ischemia (n = 6) (control). Another group of harvested livers was pretreated with a 15-min ischemic period followed by 15 min of in situ perfusion with (n = 5) or without (n = 5) a protein kinase C inhibitor, chelerythrine. Following cold ischemia, all grafts were reperfused on a perfusion circuit and the following variables evaluated: (1) hepatic graft function, (2) graft circulatory impairment, (3) hepatocellular damage, and (4) endothelial cell damage. Protein kinase C levels were also evaluated by Western blot in the cytoplasm of all grafts. RESULTS AND DISCUSSION: Ischemic preconditioned grafts demonstrate improved graft function, reduced graft circulatory impairment, and reduced endothelial cell damage as compared to cold ischemia controls. When preconditioned grafts were pretreated with chelerythrine, graft function, graft circulatory impairment, and endothelial cell damage were no different than cold ischemia controls. Ischemic preconditioned grafts demonstrated decreased levels of protein kinase C prior to cold ischemia. There was no change in protein kinase C levels in cold ischemia controls or chelerythrine-pretreated grafts prior to cold ischemia. These data indicate that modulation of protein kinase C is essential for ischemic preconditioning responses in the cold preserved hepatic graft.


Subject(s)
Ischemic Preconditioning , Liver Transplantation/methods , Liver/enzymology , Protein Kinase C/antagonists & inhibitors , Alkaloids , Animals , Benzophenanthridines , Cold Temperature , Endothelium/cytology , Endothelium/enzymology , Enzyme Inhibitors/pharmacology , Graft Survival/drug effects , Graft Survival/physiology , Ischemia/drug therapy , Ischemia/metabolism , L-Lactate Dehydrogenase/metabolism , Liver/blood supply , Liver/surgery , Liver Circulation/physiology , Phenanthridines/pharmacology , Protein Kinase C/metabolism , Swine
13.
J Surg Res ; 97(1): 54-9, 2001 May 01.
Article in English | MEDLINE | ID: mdl-11319880

ABSTRACT

INTRODUCTION: Translational control of cytokine production in endotoxin (LPS)-stimulated macrophages is poorly characterized but likely important. An early step in protein translation is engagement of mRNA by eukaryotic initiation factor 4E (eIF-4E). Translation initiation can be prevented by small 4E-binding proteins (4E-BP1 or PHAS-I) which must be phosphorylated in order to disengage eIF-4E. We examined whether LPS alters 4E-BP1 phosphorylation in macrophages. MATERIALS AND METHODS: Elicited rat peritoneal macrophages and Raw 264.7 macrophages were treated with signal transduction inhibitors and then LPS. Cells were harvested and equal protein amounts were electrophoresed (SDS-PAGE). Western blots (WB) were developed with 4E-BP1 antibody. Alternatively cell lysates were exposed to 7-methyl GTP Sepharose beads in order to isolate the cap-binding protein eIF-4E. The relative amounts of 4E-BP1 associated with eIF-4E were then determined by WB. RESULTS: Macrophage 4E-BP1 is phosphorylated upon stimulation by LPS as evidenced by the appearance of a more slowly migrating gamma (hyperphosphorylated) band on gel electrophoresis. Inhibition of both the p42/p44 MAPK pathway (PD 98059) and the p38 MAPK pathway (SB 203580) failed to alter LPS-induced 4E-BP1 phosphorylation. Rapamycin (FRAP/mTOR inhibitor) blocked 4E-BP1 phosphorylation causing a predominance of the alpha (hypophosphorylated) band. This was confirmed further by 7-methyl-GTP Sepharose isolation of eIF-4E with which 4E-BP1 coprecipitates. CONCLUSION: LPS stimulates 4E-BP1 phosphorylation in macrophages through FRAP/mTOR signaling. This pathway may contribute to the translational control of cytokine gene expression in macrophages.


Subject(s)
Carrier Proteins , Lipopolysaccharides/pharmacology , Macrophages/metabolism , Phosphoproteins/metabolism , Animals , Cell Line , Cells, Cultured , Enzyme Inhibitors/pharmacology , Eukaryotic Initiation Factor-4E , Flavonoids/pharmacology , Imidazoles/pharmacology , Intracellular Signaling Peptides and Proteins , Macrophages/drug effects , Mitogen-Activated Protein Kinase 1/antagonists & inhibitors , Mitogen-Activated Protein Kinase 3 , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Models, Biological , Peptide Initiation Factors/metabolism , Phosphorylation , Protein Biosynthesis , Pyridines/pharmacology , Rats , Sirolimus/pharmacology , p38 Mitogen-Activated Protein Kinases
15.
J Surg Res ; 96(1): 114-9, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11181004

ABSTRACT

Early recognition of hepatic function during initial graft reperfusion is important in beginning hepatic support perfusions as well as in liver transplantation. We hypothesized that both hemodynamic and metabolic perfusion variables obtained immediately after reperfusion predict eventual function during liver support or transplantation. Specific hemodynamic variables, i.e., portal vein pressure and hepatic vascular resistance, as well as metabolic variables, i.e., O(2) consumption and P(CO(2)) gradients, were compared with indices of hepatic function and damage, i.e., aqueous bile production, bile lipid outputs, lactate dehydrogenase levels, and histopathology, during an ex vivo support perfusion. O(2) consumption during early reperfusion correlated directly with unstimulated bile flows (P < 0.02) and histopathology scores (P < 0.05). Hepatic venous P(CO(2)) gradients correlated inversely with unstimulated bile flows (P < 0.05). Hemodynamic variables, i.e., portal vein pressure and hepatic vascular resistance, were inversely related with taurocholate-stimulated bile flows (P < 0.05). Hemodynamic and metabolic variables of early reperfusion are useful parameters in predicting eventual effectiveness of the harvested liver for ex vivo hepatic support perfusions.


Subject(s)
Graft Survival/physiology , Liver Circulation/physiology , Liver Transplantation , Liver/metabolism , Animals , Bile/physiology , Cholagogues and Choleretics/pharmacology , Graft Survival/drug effects , L-Lactate Dehydrogenase/metabolism , Liver/blood supply , Oxygen Consumption , Portal Vein/physiology , Predictive Value of Tests , Swine , Taurocholic Acid/pharmacology , Vascular Resistance/physiology
16.
Transplantation ; 71(2): 193-8, 2001 Jan 27.
Article in English | MEDLINE | ID: mdl-11213058

ABSTRACT

BACKGROUND: The role of nitric oxide (NO) in ischemia reperfusion (I/R) injury is controversial as both beneficial and harmful effects have been reported. We explored the potential role of a pharmacological agent recently shown to generate NO metabolically in the liver in an animal model of transplantation. METHODS: The effect of a selective hepatic NO donor, O2-vinyl 1-(pyrrolidin-1-yl)diazen-1-ium-1,2-diolate (V-PYRRO/NO), on hepatic hemodynamics and biliary function was evaluated in both the in situ and I/R pig liver. RESULTS: V-PYRRO/NO significantly reduced in situ hepatic vascular resistance (HVR) without altering systolic blood pressure. Portal vein flow was essentially unchanged during in situ infusions while hepatic artery flow nearly doubled (P=0.03). After I/R, V-PYRRO/NO infusions significantly reduced both portal vein pressure (PVP) and HVR (P=0.04). Also, serum bile acid clearance increased from 15% when taurocholate (TC) was infused alone to 46% (P=0.007) when infused simultaneously with V-PYRRO/NO. Aqueous bile production tripled with TC and V-PYRRO/NO as compared to TC alone (P=0.04). Analysis of bile outputs revealed a significant increase in biliary cholesterol, biliary phospholipid, and biliary bile acid (P<0.05) with V-PYRRO/NO infusion. CONCLUSIONS: The hepato-selective nitric oxide donor, V-PYRRO/NO, reduced hepatic resistance parameters of the pig liver both before and after I/R and improved the plasma clearance of bile acid and biliary outputs of bile acid-dependent compounds. The augmented function observed after I/R may be due to improvements in hepatic blood flow secondary to altered hepatic hemodynamics.


Subject(s)
Pyrrolidines , Animals , Hemodynamics/drug effects , Liver/physiology , Prodrugs/pharmacology , Pyrrolidines/pharmacology , Reperfusion Injury/physiopathology , Swine
17.
J Gastrointest Surg ; 5(5): 490-8, 2001.
Article in English | MEDLINE | ID: mdl-11985999

ABSTRACT

Hemodynamic properties of a donor liver, during initial reperfusion, are associated with the degree of graft preservation injury and have been proposed to correlate with subsequent markers of liver function. In the present study, hepatic hemodynamics, that is, portal venous pressure, hepatic vascular resistance, and compliance (vascular distensibility), were characterized (1) in situ before porcine livers were manipulated, (2) after these same livers were isolated and perfused within a bypass circuit, and (3) on reperfusion after 2 hours of cold ischemia. Hepatic vascular resistance was determined in each of these three states from the portal vein pressure response to differing hepatic blood flows. In addition, the response of the same livers to norepinephrine and nitroprusside was evaluated in each condition. In the in situ and isolated perfused liver, portal venous pressure increased only modestly despite doubling of hepatic flows. After cold ischemia, the pressure response to higher flows was significantly greater and much less of a reduction in hepatic vascular resistance was noted than in studies prior to cold ischemia. Unlike livers prior to cold ischemia, the pressure response to norepinephrine was attenuated following cold ischemia. The response to nitroprusside, however, remained intact reducing the portal pressure to that of in situ livers. Therefore the portal hypertension that follows cold ischemia appears to be largely provoked by the preservation injury and not by surgical manipulation or the bypass circuit. This increment in portal pressure is responsive to a nitric oxide donor.


Subject(s)
Liver Circulation , Liver Transplantation , Animals , Nitroprusside , Norepinephrine , Organ Preservation , Swine , Tissue and Organ Harvesting
18.
J Gastrointest Surg ; 5(6): 603-12; discussion 612-3, 2001.
Article in English | MEDLINE | ID: mdl-12086898

ABSTRACT

Because tumor necrosis factor-alpha (TNF-alpha) and some chemotherapeutic agents activate both apoptosis and NF-kappaB-dependent antiapoptotic genes, they may neutralize their own antitumor effects. The cell-signaling mechanisms for such chemoresistance are not clear but may involve phosphotidylinositol-3' kinase (PI3K). To clarify this we examined whether cross-signaling between PI3K and NF-kappaB enhances the antitumor effect of TNF-alpha in human pancreatic cancer cells. Quiescent pancreatic cancer cells (Panc-1, MiaPaCa-2) with TNF-alpha, Ly294002 (PI3K inhibitor), alone or combined, were restimulated with mitogen (10% fetal calf serum [FCS] to induce cell cycle entry). Proliferation (monotetrazolium), cell cycle progression (ApoBrDU and fluorescence-activated cell sorter analysis), and apoptosis (PARP cleavage; caspase-3 activation) were measured. Akt activation (Akt kinase assay) and IkappaBalpha degradation were determined by Western blot analysis. Translocation of NF-kappaB into the nucleus was examined by EMSA, whereas an NF-kappaB/luciferase reporter gene was used to quantify NF-kappaB-dependent gene expression. Statistical analysis was carried out by means of two-tailed t test (P <0.05). PI3K inhibition significantly enhanced the antiproliferative and proapoptotic effects of TNF-alpha in both cell lines, Ly294002 also blocked TNF-alpha-induced Akt activation but failed to alter cytoplasmic IkappaBalpha degradation or subsequent NF-kappaB nuclear translocation. NF-kappaB-dependent gene expression, however, was ultimately suppressed by Ly294002, suggesting that PI3k-dependent activation of NF-kappaB is IkappaBalpha independent. PI3K inhibition can block NF-kappaB-dependent gene expression regardless of cytoplasmic IkappaBalpha/NF-kappaB activation. Because it also regulates the antitumor effects of TNF-alpha, PI3K may in part determine NF-kappaB-induced chemoresistance in human pancreatic cancer.


Subject(s)
Apoptosis/drug effects , NF-kappa B/metabolism , Phosphatidylinositol 3-Kinases/metabolism , Tumor Necrosis Factor-alpha/pharmacology , Adenocarcinoma/pathology , Analysis of Variance , Humans , Pancreas/cytology , Pancreatic Neoplasms/pathology , Probability , Sensitivity and Specificity , Signal Transduction , Tumor Cells, Cultured
19.
Surg Endosc ; 14(7): 617-21, 2000 Jul.
Article in English | MEDLINE | ID: mdl-10948296

ABSTRACT

BACKGROUND: Systemic inflammatory response syndrome (SIRS) and sepsis of unknown origin are common complications of critically ill patients in the ICU. These patients frequently have unreliable clinical exams and are candidates for exploratory laparotomy. Although abdominal CT is commonly used because it is less invasive than laparotomy, it is often unreliable or unobtainable. Bedside laparoscopy is an alternative technique that may be more accurate than CT in selected patients and less invasive than laparotomy. METHODS: We performed diagnostic laparoscopy (DL) in a series of ICU patients with SIRS/septic state of unknown origin between May 1997 and June 1998. All patients were unstable and required significant respiratory and hemodynamic support. Laparoscopy was either performed in the ICU at the patient's bedside or in the operating room. CT scan of the abdomen had been performed on most of the patients who were stable enough to transport. Confirmation of diagnosis was obtained either by laparotomy, autopsy, or clinical recovery. RESULTS: Among the 17 eligible patients, 16 underwent successful DL. Insufflation was impossible in one patient because of high intraabdominal pressure. Bedside evaluations were performed in 14 of the 17 patients. There were no complications from the laparoscopy. Six patients were identified as positive (four intestinal ischemia, two cholecystitis); the other 10 had negative explorations. Follow-up on two patients with negative laparoscopy was incomplete due to denied postmortem. Laparoscopic diagnoses were confirmed in the remaining 14 patients by laparotomy (six cases), postmortem (three cases), or recovery (five cases), with an accuracy of 100%. The overall accuracy of abdominal CT obtained in nine of the 14 patients was 33%. CONCLUSIONS: DL in a select group of critical ICU patients is safe and accurate, whereas CT scan tends to be inaccurate and is often unobtainable due to patient instability. Performing the procedure at the bedside can expedite the diagnosis, eliminate the burden for transfer, and save on anesthesia and operating room charges.


Subject(s)
Laparoscopy , Systemic Inflammatory Response Syndrome/diagnosis , Feasibility Studies , Humans , Intensive Care Units , Prospective Studies , Reproducibility of Results , Systemic Inflammatory Response Syndrome/etiology
20.
J Surg Res ; 93(1): 35-40, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10945941

ABSTRACT

In liver transplantation, activation of NFkappaB occurs upon reperfusion, yet few data exist regarding NFkappaB activation during cold ischemia. We hypothesized that activation of NFkappaB may initially occur during cold ischemia, prior to reperfusion, and serve as an important determinant of postreperfusion function. To test this hypothesis, serial biopsies during porcine liver harvest were obtained immediately upon laparotomy, upon completion of dissection, after 45 and 120 min of cold ischemia, and 60 and 180 min after reperfusion. Nuclear extracts were isolated for Western blot analysis of NFkappaB. Hepatic function was assessed through bile output and sorbitol dehydrogenase (SDH) activity. NFkappaB expression was maximal at 45 min of cold ischemia and decreased by 120 min. The expression at 120 min of cold ischemia correlated with markers of postreperfusion function, namely bile flow and SDH activity. During reperfusion a second distinct peak occurred at 180 min. Increased expression of NFkappaB at 180 min of reperfusion correlated directly with prior expression at 120 min during cold ischemia and with increased SDH activity. These data indicate that nuclear expression of NFkappaB demonstrate two distinct peaks of activity, one during cold ischemia and one after reperfusion. Enhanced expression of NFkappaB during cold ischemia not only correlates directly with NFkappaB expression during reperfusion, but also correlates inversely with postreperfusion graft function.


Subject(s)
Ischemia/metabolism , Liver Transplantation , Liver/blood supply , NF-kappa B/analysis , Animals , Bile/physiology , Blotting, Western , Cold Temperature , Liver/physiopathology , NF-kappa B/physiology , Reperfusion , Succinate Dehydrogenase/metabolism , Swine
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