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Biomedical subjects

I Sayek

Publications and source records attributed to I Sayek.

At least 37 records · Page 2Linked to original sources
PubMed1999

Experimental study of the effect of different meshes on bacterial translocation.

Implantation of intraabdominal biomaterials promotes bacterial translocation (BT). In this study we planned to determine the effect of different types of mesh on the induction of BT. Swiss albino mice were divided into four groups: control, polypropylene (PP), polyglactin 910 (PG), and dura mater (DM). At hour 0, an abdominal wall defect was created in all animals. In the control group the defect was closed primarily. PP, PG, and DM meshes were used to repair the defects such that the intestines were in contact with the mesh in the remaining three groups. BT was evaluated 4, 24, and 48 hours later. At 4 hours total BT increased in the PP group compared with that in the control (p = 0.0321) and DM (p = 0.0098) groups. At 24 hours the PG group had increased BT compared with the controls (p = 0.0392) and the DM group (p = 0.0274), whereas the PP group had increased BT compared with the DM group only (p = 0.0477). At 48 hours both PG and PP groups had increased BT compared with controls (p = 0.0431 and p = 0.0001, respectively); the PP group had also increased BT compared to the DM group (p = 0.001) and the PG group (p = 0.017). In the control, DM, and PP groups there was no intragroup statistical difference. In the PG group there was a significant increase in BT at 24 hours compared to that at 4 hours (p = 0.0274). Prosthetic meshes led to increased BT compared to that with the DM mesh. This effect might be attributed to the different organic and physical properties of the meshes.

Abdominal Muscles↗
PubMed1999

Effect of persistently elevated intraabdominal pressure on healing of colonic anastomoses.

BACKGROUND: The adverse effects of elevated intraabdominal pressure (IAP) on abdominal organs are realized, but its influence on anastomotic healing has not been studied. The aim of this study was to evaluate the effect of elevated IAP on healing of colonic anastomoses. METHODS: Thirty rats, which all had right colonic anastomoses, were divided into five groups. Group 1 was the control group, and group 2 had fecal peritonitis. IAP was maintained between 4 to 6 mm Hg in group 3, 8 to 12 mm Hg in group 4, and 14 to 18 mm Hg in group 5 until all rats were sacrificed on day 4. Bursting pressures and tissue hydroxyproline concentrations of anastomoses were then analyzed and compared. RESULTS: Mean +/- SEM of bursting pressures were 143+/-2.9 mm Hg in group 1, 72+/-14.4 mm Hg in group 2, 77.3+/-7.9 mm Hg in group 3, 57.5+/-11.2 mm Hg in group 4, and 40.1+/-9.6 mm Hg in group 5 (P<0.0001, one-way analysis of variance [ANOVA]). Mean +/- SEM of tissue hydroxyproline concentrations were 5.3+/-0.3 microg/mg in group 1, 4.7+/-0.5 microg/mg in group 2, 4.6+/-0.6 microg/mg in group 3, 3.6+/-0.5 microg/mg in group 4, and 2.4+/-0.2 microg/mg in group 5 (P = 0.0026, one-way ANOVA). The bursting pressure and hydroxyproline concentrations had good correlation (P<0.001, r = 0.76). CONCLUSIONS: Elevated IAP delays healing of colonic anastomoses and 4 to 6 mm Hg IAP delays healing as much as fecal peritonitis. More elevated IAP delays healing more than fecal peritonitis. These events may be clinically important and may result from local-systemic effects of IAP.

Abdomen↗
PubMed1999

Effects of adrenaline or endotoxin tolerance states on mesenteric blood flow in endotoxaemia.

BACKGROUND: Endotoxic shock is associated with release of catecholamines as well as decreased mesenteric vascular perfusion, which is thought to cause remote organ injury. Adrenaline tolerance was reported to decrease mortality in endotoxic shock and have cross-tolerance with endotoxin tolerance. Our aim was to investigate the effect of these two tolerance conditions on the lipopolysaccharide (LPS)-induced decrease in mesenteric blood flow (MBF). METHODS: Adrenaline tolerance was developed by injecting 0.03 mg/kg adrenaline to Swiss-albino mice, gradually increasing the dose to 2 mg/kg over 5 days. Endotoxin tolerance was developed by injecting saline for 4 days and LPS 1 mg/kg at the fifth day. Control animals were injected with saline for 5 days. At 72 h after completion of injections, half of the animals in each group were challenged with saline and the other half with 20 mg/kg LPS, at 0 h. Mesenteric blood flow was measured at 4 and 24 h. RESULTS: Neither endotoxin nor adrenaline tolerance prevented an LPS-induced decrease in MBF. CONCLUSION: A low dose of LPS prior to a higher dose does not prevent an LPS-induced decrease in MBF and may actually prime for a decrease. Also, catecholamines are not primary mediators of LPS-induced decreases in MBF.

Animals↗
PubMed1999

Effect of intraperitoneal and extraperitoneal insertion of mesh on bacterial translocation: does it make a difference?

OBJECTIVE: To asses the effect of insertion of mesh, with or without contact with the peritoneum, on the induction of bacterial translocation. DESIGN: Open experimental study. SETTING: Surgical research laboratory, Turkey. SUBJECTS: 158 Swiss albino mice. INTERVENTIONS: A defect in the abdominal wall was created. In the control group, the defect was closed primarily. In the extraperitoneal group, polypropylene mesh was sutured over the abdominal wall after primary closure of the peritoneum and in the intraperitoneal group, polypropylene mesh was sutured to close the created defect so that it was in contact with the intestines. MAIN OUTCOME MEASURES: Bacterial translocation at 4, 24 and 48 hours. RESULTS: Insertion of mesh in contact with the peritoneum led to increased bacterial translocation to mesenteric lymph nodes at 4 (p = 0.02) and 48 (p = 0.03) hours compared with insertion without contact. CONCLUSION: Contact between a foreign body and the peritoneum is required to induce bacterial translocation.

Abdominal Muscles↗
PubMed1999

Effects of laparotomy, and carbon dioxide and air pneumoperitoneum, on cellular immunity and peritoneal host defences in rats.

OBJECTIVE: To assess the effects of laparotomy, and insufflation of carbon dioxide and air, on the immune system in rats. DESIGN: Randomised laboratory study. SETTING: Teaching hospital, Turkey. ANIMALS: 77 Wistar rats randomly allocated to 2 groups one of which was sensitised with dinitrofluorobenzene (DNFB, n = 43) and one of which was not (n = 34). INTERVENTIONS: The DNFB group was sensitised and subdivided into control (n = 8), laparotomy alone (n = 7), and insufflation with carbon dioxide (CO2) for 30 and 60 mins (n = 7 in each) or room air for 30 and 60 mins (n = 7 in each). A week later DNFB was reapplied to the ears. In the group not sensitised with DNFB the animals were subdivided similarly, the corresponding numbers in each group being, 6, 6, 6, 6, 5, and 5. MAIN OUTCOME MEASURES: Delayed type hypersensitivity (DTH) measured by ear swelling in the DNFB group, and peritoneal bactericidal activity, total free peritoneal cell counts (TPC), and cell types in the non-sensitised group. RESULTS: There were significant differences in the degree of ear swelling in the DNFB group between control and laparotomy groups (p = 0.0001) and between control and both insufflations of air (p = 0.002 and p = 0.0003, respectively). In the non-sensitised group peritoneal bactericidal activity was significantly increased after 7 hours in the 60 mins air insufflation group (p = 0.04). At 24 hours there were no differences among the groups. TPC were not affected. The number of peritoneal polymorphonuclear leucocytes (PMN) was significantly higher in the laparotomy alone group than in the control or any of the insufflation groups (p < 0.05). CONCLUSIONS: Laparotomy and air insufflation depressed cell-mediated immunity. Peritoneal bactericidal activity was affected only after 60 minutes of air insufflation.

Air↗
PubMed1999

Experimental study of the effects of splenectomy and partial splenectomy on bacterial translocation.

BACKGROUND: The aim of this study is to evaluate the effect of splenectomy and partial splenectomy in a burn-induced bacterial translocation model and to study Kupffer cell (KC) morphology and number. METHODS: Mice were divided into sham-burn and burn groups. Each group was also subdivided to sham-splenectomy, partial-splenectomy, and splenectomy subgroups. At day 0, operations were performed. At the postoperative 10th day, a sham burn or burn injury was made in all animals. Twenty-four hours later, cultures for bacterial translocation were obtained and livers were evaluated for the quantity and morphology of KCs. RESULTS: Burned-splenectomized animals had significantly decreased bacterial translocation when compared with sham-splenectomized animals (p = 0.031). Interestingly, in both the sham-burned and burned groups, splenectomy subgroups had significantly higher numbers of KCs compared with partial-splenectomy and sham-splenectomy subgroups (p<0.00000). Burn injury caused a significant decrease of KC numbers in all subgroups compared with their correspondent sham-burned subgroups (p<0.05). CONCLUSION: Results revealed that splenectomy decreases bacterial translocation and also increases the number of KCs.

Animals↗
PubMed1999

Epinephrine and endotoxin tolerance differentially modulate serum cytokine levels to high-dose lipopolysaccharide challenge in a murine model.

BACKGROUND: The epinephrine tolerance state has been demonstrated to increase survival in endotoxic shock and was claimed to have cross-tolerance with endotoxin tolerance. With use of these data, we aimed to determine the effect of epinephrine and endotoxin tolerance on major cytokine levels in a lipopolysaccharide challenge in mice. METHODS: Epinephrine tolerance was induced by beginning with a low dose and gradually increasing to a lethal dose. Endotoxin tolerance was induced by injecting saline solution for 4 days and lipopolysaccharide 1 mg/kg on the fifth day. After these procedures, saline solution or 20 mg/kg lipopolysaccharide was injected into animals. Peak serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin 1 beta, interleukin 6 (IL-6), interleukin 10 (IL-10), and interleukin 12 (IL-12) were assayed. RESULTS: The lipopolysaccharide injection increased the levels of all the cytokines in the control and epinephrine-tolerant animals. TNF-alpha, IL-6, and IL-10 levels were lower in endotoxin-tolerant animals compared with controls. Epinephrine-tolerant animals had higher levels of TNF-alpha, IL-6, and IL-12 than the controls did. CONCLUSION: Epinephrine tolerance primes for an exaggerated release of TNF-alpha, IL-6, and IL-12 in response to lipopolysaccharide challenge, suggesting anti-inflammatory and immunosuppressive effects by epinephrine. The anti-inflammatory effect was not mediated through increased IL-10 release. Endotoxin tolerance selectively modulated cytokine release.

Animals↗
PubMed1999

[Laparoscopic management of echinococcal cysts of the liver].

Even though echinococcal cysts have been cured by puncture and instillation of scolicidal medications, surgery is still the mainstay of the treatment of hydatid disease. The aim of the surgical treatment is the elimination of scolices, the removal of all viable parts of the cyst and the obliteration of the remaining cavity. This can be achieved by resective procedures, but also by a more conservative approach with drainage and obliteration of the cyst. The latter procedure can be done by open surgery or laparoscopically. The disadvantages of the laparoscopic approach are the increased danger of contamination of the abdominal cavity with scolices and difficulties to aspirate a highly viscous cyst content. Furthermore, cysts which are located deep in the parenchyma of the liver should not be approached laparoscopically because of the significant danger of hemorrhage. The advantage of the laparoscopic approach in selected cysts, i.e. those which are located superficially and having a liquid content, are a shorter hospital stay, lower incidence of wound infection and the ability of the surgeon to inspect the inside of the cyst more thoroughly and rule out daughter cysts and connections to the biliary tract. A review of the literature (n = 76) indicates that in most laparoscopically treated hydatid cysts of the liver a simple drainage (59%) or an unroofing (31%) is performed. The complication rate is 21%. Because there are no longterm observations after laparoscopic operations for hydatid disease the question of recurrence cannot yet be answered.

Echinococcosis, Hepatic↗
PubMed1998

An experimental study of the effect of aprotinin on intestinal adhesion formation.

BACKGROUND: Depression of fibrinolysis is known to be a major mechanism for postoperative adhesion formation. Because aprotinin inhibits fibrinolysis it may lead to an increase in adhesion formation whereas its anti-inflammatory effects may lead to a decrease in adhesion formation. Our aim is to clarify conflicting results in previous literature. METHODS: Basal levels of intestinal hydroxyproline (OHP) content and local fibrinolytic activity (LFA) were determined using naive groups. In the experiment groups, adhesions were created by scraping and creating a transient ischemia of a segment of terminal ileum. Group I and II rats were injected subcutaneous (s.c.) normal saline (NS) for 3 days and single dose intraperitoneal (i.p.) NS, respectively. Group III and IV rats were injected s.c. aprotinin for 3 days and single dose i.p. aprotinin, respectively. Group V rats were injected intramuscular methylprednisolone (MP) for 3 days. LFA and OHP levels were determined on the second and fifth postoperative days. The severity of adhesion formation was graded on the fifth day. RESULTS: Aprotinin decreased both the severity of adhesions and OHP levels whereas MP decreased only the severity of adhesions. There was an early depression of LFA at the second day in both NS and MP groups increasing to basal levels at the fifth day. OHP levels showed significant correlation with adhesion severity. CONCLUSION: Results showed that aprotinin decreased intra-abdominal adhesion formation probably by preventing early depression of LFA.

Animals↗
PubMed1998

Experimental study of the effect of adrenaline tolerance on intestinal ischaemia-reperfusion.

BACKGROUND: Adrenaline tolerance improves survival in animal models of shock. The purpose of this study was to determine the effects of adrenaline tolerance on intestinal ischaemia-reperfusion in a mouse model. METHODS: Adrenaline tolerance was developed by injecting intravenous adrenaline, gradually increasing the dose to 2 mg/kg over 5 days. In experimental animals the superior mesenteric artery was clamped for 120 min and then released. Evans blue dye was given intravenously to all animals to quantify pulmonary microvascular injury. Some 60 min after clamp release, the animals were killed and the effects of reperfusion assessed on tissue samples. RESULTS: Evans blue dye concentrations were significantly higher in animals with intestinal ischaemia-reperfusion than in those having sham intestinal ischaemia-reperfusion or in adrenaline-tolerant mice having intestinal ischaemia-reperfusion or sham ischaemia-reperfusion (P< 0.01). Malonyldialdehyde levels increased significantly in the lung in the intestinal ischaemia-reperfusion group compared with those in the sham ischaemia-reperfusion group (P< 0.001 for liver, lung and small intestine), whereas there was no difference in adrenaline-tolerant animals. There was no significant change induced by adrenaline tolerance in myeloperoxidase levels in any organ. CONCLUSION: Adrenaline tolerance reduced the lung permeability caused by intestinal ischaemia-reperfusion. Catecholamines may play a role in free radical generation induced by ischaemia-reperfusion.

3,4-Methylenedioxyamphetamine↗
PubMed1998

Evidence that aminoguanidine inhibits endotoxin-induced bacterial translocation.

BACKGROUND: The role of inducible nitric oxide synthase (iNOS) in endotoxin-induced bacterial translocation was investigated by using its specific blocker aminoguanidine in 46 albino mice (25-35 g) allocated into four groups. METHODS: The first group received intraperitoneal saline (control; 0.9 per cent w v(-1) sodium chloride 1 ml kg(-1); n=6), the second group intraperitoneal endotoxin (Escherichia coli lipopolysaccharide 055:B5 20 mg kg(-1); n=19), the third group intraperitoneal aminoguanidine (20 mg kg(-1), 20 min before and 12 h after saline; n=6) and the fourth group both endotoxin and aminoguanidine intraperitoneally (n=15). Some 24 h later, the animals were anaesthetized with ether and blood samples were collected by cardiac puncture together with mesenteric lymph node (MLN), spleen and liver specimens under aseptic conditions. Specimens were then cultured to determine the presence of colony-forming units as an index of bacterial translocation. RESULTS: No bacterial growth was detected in samples from the first and third groups. Colony-forming bacteria were found in ten of 14 MLN samples, eight of 14 spleens, four of 14 livers and three of 14 peripheral blood samples in the second group, with E. coli being the predominant pathogen. In contrast, in the fourth group, colony-forming bacteria were found in only three of 14 MLN samples (P=0.02 versus the second group), three of 14 spleens and one of 14 liver specimens. None of the values in the fourth group was significantly different from those in the saline control group. CONCLUSION: The inhibition of iNOS during endotoxaemia by its specific blocker aminoguanidine attenuates the incidence of bacterial translocation in mice. These results may be exploited clinically for the prophylaxis and treatment of septic states.

Animals↗
PubMed1998

Arterial thrombosis leading to intestinal infarction in a patient with Behçet's disease associated with protein C deficiency.

Behçet's disease may be a possible cause of both occlusive and aneurysmal arterial involvement as well as recurrent venous thrombosis. A case of Behçet's disease complicated with vascular involvement leading to intestinal infarction is presented. A 41-yr-old man suffering from Behçet's disease for 15 yr presented with a 2-day history of severe abdominal pain and bloody diarrhea. Intestinal infarction secondary to thrombosis of the superior mesenteric artery had been diagnosed during surgical exploration 3 yr previously. He was started on anticoagulation with nutritional support. The patient was readmitted with severe diarrhea and malabsorption symptoms 3 yr after intestinal resection. A thrombus located in the posterior wall of the infrarenal portion of aorta was detected by aortography and ultrasonography. Although thrombosis is a relatively common complication of Behçet's disease caused by vasculitis, protein C deficiency, which is a pertinent laboratory finding in this case, might be a secondary factor in the thrombotic event. This is the first case reported of mesenteric artery thrombosis leading to bowel infarction and abdominal aorta thrombosis associated with protein C deficiency.

Adult↗
PubMed1998

Influence of the heterogeneity of P-glycoprotein expression on technetium-99m-MIBI uptake in breast cancer.

UNLABELLED: We prospectively studied a total of 30 patients with breast cancer to evaluate the relationship between the degree of accumulation of 99mTc-sestamibi (MIBI) and the heterogeneity of p-glycoprotein expression in tumor tissues. METHODS: Twenty patients during initial presentation and 10 patients during post-therapy evaluation underwent contemporaneous 99mTc-MIBI imaging and surgery or biopsy. Immunohistochemical studies were performed on multiple nonconsecutive sections of the same tumor using a p-glycoprotein-specific monoclonal antibody, JSB-1. Tumor-to-background (T/B) ratios were correlated with the level and heterogeneity of p-glycoprotein expression determined by immunohistochemical studies. RESULTS: The T/B ratios were lower for those tumors with strong p-glycoprotein expression (Group 1) than those with strong-to-weak expression (Group 2) or those with weak-to-no expression (Group 3) (1.32 +/- 0.19 and 1.85 +/- 0.56 and 2.86 +/- 1.06, respectively). There was statistically significant difference in T/B ratios between all 3 groups (p < 0.005). Although T/B ratios for Group 1 and Group 3 were clearly distinct from one another with no overlapping values, the values for Group 2 overlapped with those of Group 1 and Group 3. When we evaluated the entire patient group with excluding those with strong-to-weak expression, although the p value remained the same (p < 0.001), we obtained a stronger correlation between T/B ratios and p-glycoprotein expression (r = 0.808 versus 0.735). CONCLUSION: Due to the heterogeneous expression of p-glycoprotein, both immunohistochemistry and 99mTc-MIBI scintigraphy may yield confounding results by contrasting with one another if the presence or absence of p-glycoprotein is not extensively explored. Although our data confirmed that 99mTc-MIBI imaging is useful in the determination of the presence of multidrug resistance in patients with breast cancer, the issue of heterogeneous expression of the antigen should be further investigated when unexpected results are obtained.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Role of endotoxin and nitric oxide in the pathogenesis of renal failure in obstructive jaundice.

BACKGROUND: There is an increased incidence of postoperative renal failure in patients with obstructive jaundice. The purpose of this study was to investigate the role of endotoxaemia and nitric oxide in this association. METHODS: In bile duct-ligated, sham-operated and control rats, plasma total bilirubin levels, creatinine clearance and plasma endotoxin were determined. Endothelium-dependent vasodilatation to acetylcholine, and endothelium-independent vasodilatation to nitroglycerine and forskolin were evaluated in isolated perfused rat kidney. RESULTS: Twenty-one of 27 bile-duct ligated rats had endotoxaemia. Plasma bilirubin levels were higher and creatinine clearance was significantly reduced in the bile duct-ligated endotoxin-positive group compared with values in the other groups. Furthermore, in the isolated perfused rat kidney from rats with endotoxaemia, basal perfusion pressure and renal vascular relaxation to acetylcholine and nitroglycerine which is mediated by guanosine cyclic 3',5'-cyclic monophosphate (cGMP) were significantly reduced, but relaxation to forskolin mediated by adenosine cyclic 3',5'-cyclic monophosphate did not change. CONCLUSION: Endotoxaemia in obstructive jaundice may induce overproduction of nitric oxide that may lead to impairment of cGMP-associated vasodilatation and disrupt autoregulation of the renal vascular bed. This may contribute to renal failure in obstructive jaundice.

Acetylcholine↗