Biomedical subjects

S Bengmark

Publications and source records attributed to S Bengmark.

At least 37 records · Page 2Linked to original sources

PubMed1996

Nutritional support to prevent and treat multiple organ failure.

Enteral nutrition (EN) has several advantages over parenteral nutrition (PN) for postoperative/posttrauma patients. Modern technologies for tube-feeding have made early EN possible. Jejunal tube-feeding has advantages over gastric tube-feeding: faster metabolic recovery, less vomiting, and less risk of regurgitation and aspiration. Immediate or early EN stimulates the splanchnic and hepatic circulations, improves mucosal blood flow, prevents intramucosal acidosis and permeability disturbances, and eliminates the need for stress ulcer prophylaxis. Saliva containing important antimicrobial substances and gastric acidity are important in sepsis prevention. Chewing, saliva, and gastric acidity support gastric nitric oxide (NO) release, important for mucosal blood flow, gastrointestinal (GI) motility, mucus formation, and bacteriostasis. An oral supply of NO-donating substances and chewing of nitrate-rich food, such as lettuce or spinach, can be useful. Oral and mucosa-protective lipids are recommended. H2 blockers and saliva-inhibiting drugs are avoided. Immediate EN should be given, starting with 25 ml/hr and increasing to 100 ml/hr over 24 to 48 hours. For the immunocompromised patient special attention should be given to the purity of water. Bottled water can contain bacteria such as Pseudomonas. Food antioxidants such as glutathione, vitamin E, and beta-carotenes are important. Ingredients for the colonic mucosa are important. Approximately 10% of caloric need is satisfied by so-called colonic food (prebiotics), fermented at the level of the colonic mucosa to produce colonic mucosa nutrients and to prevent gut origin sepsis. More than 10 g of fiber per day is recommended. The fermenting flora (probiotic flora) is deranged owing to disease or antibiotic treatment, and resupply of flora is important. A new concept of ecoimmune nutrition is presented for enteral supply of mucosa-reconditioning ingredients: new surfactants, pseudomucus, fiber, amino acids such as arginine, and mucosa-adhering Lactobacillus plantarum 299.

Energy Intake↗

PubMed1996

Dynamics of bacterial translocation in acute liver injury induced by D-galactosamine in rat.

Bacterial translocation may play a role in acute liver injuries as high rates of infectious and septic complications are observed in these clinical conditions. Increased passage of endotoxin and translocating bacteria not only potentiates the extent of liver injury, but may also play a determining role in its final outcome. In this paper the incidence of bacteria] translocation in acute liver injury in rats is evaluated with other important pathological changes observed at different time points after liver injury induced by intraperitoneal administration of D-galactosamine. The bacterial translocation to the blood and other extraintestinal sites starts 3 h after induction of liver injury and is not found to be related to light microscopic changes in the liver or ileal or cecal mucosa, detectable levels of endotoxin in the portal blood, or DNA changes in the small and large intestinal mucosa, but corresponds to the release of liver enzymes in the serum.

Analysis of Variance↗

PubMed1996

Pectin-supplemented enteral diet reduces the severity of methotrexate induced enterocolitis in rats.

BACKGROUND: Administration of methotrexate (MTX) to rats fed an elemental diet results in a high mortality from severe enterocolitis. Previous studies have shown that pectin is an important precursor of substrates for intestinal structure and function and may facilitate intestinal recovery after enterocolitis. The aim of this study is to evaluate the effect of pectin on MTX-induced enterocolitis in rats. METHODS: Rats received intragastric infusion of either 1% pectin-supplemented or pectin-free elemental diet from the beginning of the study via a gastrostomy. On the 4th day animals received either MTX, 20 mg/kg intraperitoneally, or saline injection and were killed on the 7th day for sampling. RESULTS: Pectin supplementation significantly decreased body weight loss, organ water content, and intestinal myeloperoxidase levels and increased mucosal protein, DNA, and RNA content in enterocolitis rats. The intestinal permeability was increased by administration of MTX, and pectin supplementation significantly reversed the increased permeability in the distal small bowel and colon. Pectin supplementation also lowered the magnitude of bacterial translocation, decreased plasma endotoxin levels, and restored bowel microecology. CONCLUSIONS: Pectin significantly decreased MTX-induced intestinal injury and improved bowel integrity.

Animals↗

PubMed1996

A bacteriologic and scanning electron microscope study after implantation of foreign bodies in the biliary tract in rats.

BACKGROUND: Bacterial adherence to the stent surfaces, concomitant colonization, and possible stent blockage are the main complications after the use of biliary stents. The present study was assigned to investigate bacteriologic and morphologic changes in the biliary tract after the implantation of biliary drain materials. METHODS: Rubber and silicone pieces with a surface area of 1 cm2 were implanted into the biliary tract in rats after temporary obstruction of the common bile duct by the use of a mini-occluder. The animals were killed at 4, 8 and 14 weeks, respectively, after implantation, and the implants were retrieved, cultured, and examined by scanning electron microscopy (SEM). Bacterial culture and SEM were also performed on tissue samples obtained from the mucosal surface of the biliary tract. RESULTS: Bacterial colonization and biofilm formation were found on the surfaces of the implanted materials and on the mucosal surface of the biliary tract in animals with implants but not on the biliary tract mucosa in rats without implants. CONCLUSION: Foreign bodies implanted in the biliary tract facilitate bacterial adherence not only to the surface of the implants but also to the mucosal surface in the biliary tract.

Animals↗

PubMed1996

The effect of pretreatment with endotoxin and lactobacillus on bacterial translocation in acute liver injury.

OBJECTIVE: To evaluate the effect of pretreatment with endotoxin or Lactobacillus reuteri pretreatment on bacterial translocation after acute liver injury. DESIGN: Experimental study. SETTING: University department, Sweden. SUBJECTS: 96 Sprague-Dawley rats were divided into four groups of 24 each. Three of them received intraperitoneal D-galactosamine, the fourth received pyrogen free water and was used as the normal control. Twenty-four hours later the study was terminated and samples collected. INTERVENTIONS: Endotoxin and L reuteri R2LC were injected intraperitoneally three days, one week, and two weeks before induction of liver injury. MAIN OUTCOME MEASURES: Extent of liver injury and bacterial translocation to mesenteric lymph nodes, liver, and systemic blood. RESULTS: The extent of liver injury and rate of bacterial translocation were lower three days after pretreatment with endotoxin, than after pretreatment with L reuteri. There was no other difference among the other groups. High concentrations of serum endotoxin were detected three days after pretreatment with endotoxin. There were no significant changes in small intestinal and caecal bacterial counts. CONCLUSION: Pretreatment with endotoxin effectively prevented liver injury by D-galactosamine and subsequent bacterial translocation. Pretreatment with L reuteri had no beneficial effect.

Animals↗

PubMed1995

Alterations of lipid contents in blood, hepatocytes, and enterocytes in the early stage of acute liver failure induced by 90% hepatectomy in the rat.

Potential alterations in lipid metabolism in the early stage of acute liver failure are poorly elucidated. In the present study, acute liver failure was induced by subtotal hepatectomy (90%) in the rat in order to investigate early alterations in lipid contents in blood, hepatocytes, and enterocytes. Hypocholesterolemia and hypotriglyceridemia appeared 2 and 6 hr following subtotal hepatectomy. Plasma levels of high density lipoprotein-cholesterol were significantly lower in rats with acute liver failure than in controls, which may be associated with hypocholesterolemia. An increase in erythrocyte phospholipids and triglycerides was seen from 2 hr on after hepatectomy. The content of phospholipids and triglycerides was reduced in isolated enterocytes from the proximal small intestine and increased in enterocytes from the distal small intestine. Isolated hepatocytes from the remnant liver exhibited an increase in phosphatidylethanolamine and a decrease in phosphatidylinositol. Levels of enterocyte phosphatidylserine were elevated in both the proximal and the distal small intestine, while they diminished in the distal small intestine. Sphingomyelin content increased in the proximal small intestine. The recognition of lipid alterations in the intestine-liver-systemic circulation axis in the early stage of acute liver failure may be beneficial in improving the recovery from acute liver failure.

Animals↗

PubMed1995

Fibronectin on the surface of biliary drain materials--a role in bacterial adherence.

The present study deals with the demonstration of deposited fibronectin (Fn) on the surfaces of implanted biliary drain materials and the role of deposited Fn in promotion of bacterial adherence. Rubber pieces that had been implanted in the biliary tracts of rats for 4 weeks were retrieved and the following approaches employed for further investigations: (1) adherence of [methyl-3H]thymidine-labeled Escherichia coli to implanted and unimplanted rubber pieces; (2) blocking the adherence of radiolabeled bacteria with anti-Fn antibodies; (3) detection of deposited Fn by 125I-labeled anti-Fn IgG; and (4) immunoblotting of the surface eluate from implanted rubber pieces. The results show that in the presence of serum, plasma, or bile, the number of E. coli cells adherent to implanted rubber pieces was 10 times higher than that adherent to the unimplanted pieces (P < 0.001) and that the adherence was reduced by pretreatment of implanted pieces with anti-Fn antibodies. Furthermore, the implanted pieces appeared to have a high affinity for 125I-labeled rabbit anti-Fn IgG rather than the 125I-IgG without anti-Fn fraction. Fn was also found in the surface eluate of implanted pieces by immunoblotting of the eluate. The results in the present study suggest that Fn may be involved in implant-associated infections in the biliary tract.

Animals↗

PubMed1995

Reticuloendothelial system function in acute liver injury induced by D-galactosamine.

AIMS/METHODS: Reticuloendothelial system function, as assessed by clearance of radiolabelled bacteria, was evaluated in acute liver injury induced by D-galactosamine in rats, and compared with that after 70% liver resection model. RESULTS: Reticuloendothelial system function was significantly impaired in both instances, but the extent and the pattern of reticuloendothelial system impairment differed in the two models. While the elimination rate of the radiolabelled bacteria (k-value) decreased in both the liver resection and D-galactosamine groups (19% and 52%, respectively), the corrected phagocytic index (alpha) increased in 70% liver resection (247%), indicatine increased activity among the remaining reticuloendothelial system cells of the liver. Estimation of subserosal organ blood flow showed decreased flow to the cecum and distal small intestine (correction of intesting) in both groups, whereas it was significantly increased (477%) in the remaining parts of the liver in the liver resection group. CONCLUSIONS: These findings show that reticuloendothelial system activity is deranged in both these groups, which may explain the increased occurrence of bacterial complications observed in corresponding clinical conditions.

Animals↗

PubMed1995

Mesocaval shunt or repeated sclerotherapy: effects on rebleeding and encephalopathy--a randomized trial.

BACKGROUND: Sclerotherapy is usually effective in controlling acutely bleeding esophageal varices. It may not be as effective as shunt surgery for prevention of rebleeding; therefore we undertook a prospective study comparing interposition mesocaval shunt (MCS) and repeated sclerotherapy. METHODS: Forty-five patients (mean age, 52.6 +/- 9.8 years) with variceal bleeding were randomized after emergency endoscopic sclerotherapy either to repeat variceal obliteration followed by regular check endoscopy (n = 21) or to elective interposition mesocaval shunting by use of 14 mm polytetrafluoroethylene graft (n = 24). There was an equal distribution of Child's classes in the two groups. RESULTS: In the sclerotherapy group 12 patients had recurrent hemorrhages causing five deaths compared with the shunt group, in which four patients had postoperative bleeding but without associated death. No difference was noted in the incidence of encephalopathy despite the development of total shunting 1 year after MCS. The median hospital stay was similar; 34.5 days (MCS) and 33 days (sclerotherapy). The number of intensive care unit days was also similar in the two groups. No difference was noted in survival in patients with Child's A and Child's B disease in the treatment groups. In patients with Child's C cirrhosis there was a statistically significant longer survival in patients undergoing MCS compared with patients undergoing sclerotherapy. CONCLUSIONS: The results of the study show that the rate of rebleeding is significantly higher after sclerotherapy than after mesocaval shunting. In patients with Child's C cirrhosis MCS may be an alternative to sclerotherapy for the prevention of rebleeding from esophageal varices in patients not suitable for transplantation.

Adult↗

PubMed1995

Effect of bile obstruction on liver regeneration following major hepatectomy: an experimental study in the rat.

The regeneration of the liver following resection is regulated by a variety of factors and it might be expected that jaundice influences the process. We therefore evaluated the regenerative response to major hepatectomy in bile-obstructed rats. Two weeks after ligation of the common bile duct, a standardized 77% hepatectomy was undertaken. The jaundiced animals showed an augmented liver regeneration compared to nonjaundiced individuals (p < 0.01). However, blood clearance of radiolabelled Escherichia coli bacteria was impaired (p < 0.01) in animals with bile obstruction at 7 days after the hepatectomy, accompanied by reduced bacterial uptake in the liver as a sign of impaired reticuloendothelial system function.

Animals↗

PubMed1995

Experimental foreign-body infection in the biliary tract in rats.

BACKGROUND: Biomaterials used for biliary drainage may potentially result in biomaterial-associated infections. METHODS: Foreign-body infection in the biliary tract was investigated in rats. Rubber drain pieces were implanted in the biliary tract in rats for 1-4 weeks, followed by challenges with 10(2) to 10(4) colony-forming units (cfu) Escherichia coli injected into the common bile duct. The rate of infection was calculated, the bacterial growth in the biliary tract was observed over 72 h after challenges, and the opsonic activity in bile and in sera was assessed. RESULTS: In the group with drain material, inocula as small as 10(2) cfu produced persisting infection in the common bile duct in 90% of animals, whereas the same number of E. coli infected only 30% of rats in the control and sham implantation groups (p < 0.01, chi-square test). Complement-mediated opsonic activity in bile of animals with implanted drain pieces gradually decreased with time, whereas opsonic activity in sera from the same animals remained unchanged. CONCLUSIONS: Implants in the biliary tract impair local host defense, resulting in an increased susceptibility to microbial infection.

Animals↗

PubMed1995

Exogenous phospholipid reduces postoperative peritoneal adhesions in rats.

OBJECTIVE: To find out if the previously described ability of phosphatidylcholine to reduce peritoneal adhesions is specific to it, or if other phospholipids such as phosphatidylinositol (PI) or DL-phosphatidylcholine dilauryl (DL-PC) have similar effects. DESIGN: Laboratory experiment. SETTING: University hospital, Sweden. MATERIALS: 160 rats which had had intraperitoneal adhesions induced at laparotomy by peritoneal defects repaired in one of two models. INTERVENTIONS: PI was given intraperitoneally either once in a dose of 20 or 40 mg/rat at the end of the operation, or at the end of the operation and repeated on the second and third postoperative days. DL-PC was given once at the end of the operation in a dose of either 20 or 40 mg/rat. MAIN OUTCOME MEASURES: Adhesions were assessed a week after operation by an observer who was unaware of the treatment given. RESULTS: PI given on three consecutive days significantly reduced adhesions formed postoperatively in both models (p < 0.05). Neither PI nor DL-PC given in a single dose of 20 mg/rat had any effect, whereas both PI and DL-PC given in single doses of 40 mg/rat significantly reduced adhesions (p < 0.05). CONCLUSION: Both PI and DL-PC are effective in the prevention and limiting of postoperative adhesions in rats.

Animals↗

PubMed1994

Influence of dearterialization on distribution of absolute tumor blood flow between hepatic artery and portal vein.

BACKGROUND: Conflicting results have been obtained regarding blood flow distribution to liver tumors. The emphasis on portal vein perfusion has had a great impact on the design of treatment protocols. METHODS: Double microsphere technique with reference organ sampling was used for the measurement of hepatic artery and portal vein blood flow of an implanted liver tumor in 42 rats after permanent dearterialization and repeated dearterialization (2 hours/day) compared with untreated sham-operated controls. RESULTS: Portal venous blood flow constituted 16% of total tumor blood flow and slightly increased after permanent and repeat dearterializations, though the elevation was not statistically significant as compared with sham-treatment (P > 0.05). In another 3 groups, the treatment was extended to 10 days, and tumor blood flow was measured in central and peripheral parts separately. Arterial blood flow further decreased in tumor periphery and was still lower in the tumor center (P < 0.01 versus tumor periphery), and portal blood flow declined concomitantly to 4% of total tumor blood perfusion. However, no difference in portal blood flow between the tumor center and periphery could be demonstrated (P > 0.05). Furthermore, portal supply increased neither in tumor periphery nor in tumor center after both permanent and repeated dearterialization (P > 0.05). CONCLUSION: The authors' results showed that portal blood flow did contribute to tumor circulation, but made up only 16% of blood flow when tumors were small and declined to 4% of entire tumor blood supply when tumors became large. Portal perfusion also declined as tumors grew larger and did not compensate for the withdrawal of tumor arterial blood supply after dearterialization.

Animals↗

PubMed1994

Bacterial translocation, intestinal ultrastructure and cell membrane permeability early after major liver resection in the rat.

The process and route of bacterial translocation from the gut after major liver resection remain unclear. In the present study enteric bacterial translocation, enterocyte ultrastructure in the ileum and colon, the process and route of bacterial invasion and the permeability of the cell membrane system and blood-tissue barrier were evaluated in rats receiving sham operation, and 70 or 90 per cent hepatectomy. The incidence of bacterial translocation to mesenteric lymph nodes was 80-100 per cent in rats 6 h after 70 per cent and 2-4 h after 90 per cent hepatectomy, and 80-100 per cent to the systemic circulation 2-4 h after 90 per cent hepatectomy but only 20 per cent to the portal vein. An increase in bacterial adherence to the intestinal surface, damage to the permeability of the cell membrane system and blood-tissue barrier, and pathological alterations in the ileum and colon developed, correlating with the extent of liver removed and the time that had passed after hepatectomy. Most translocating bacteria appeared in morphologically intact enterocytes with increased membrane permeability, in antigen-presenting cells and in submucosal lymphatics, but some bacteria were also seen within damaged enterocytes 4h after 90 per cent hepatectomy. These results indicate that altered permeability of the cell membrane system may be one of the earliest characteristics of challenged enterocytes, and that enteric bacteria translocate through both morphologically normal and abnormal enterocytes. Translocation occurred mainly into the lymphatics, bacteria either being 'carried' by antigen-presenting cells or entering by active invasion.

Animals↗

PubMed1994

Enhanced Kupffer cell activity after repeated hepatic arterial ischaemia in an experimental model.

Kupffer cells are important for host defence against both foreign invaders and neoplasia. Several studies have demonstrated that ischaemia and reperfusion activates Kupffer cells. The effect of hepatic arterial ischaemia on Kupffer cell function was assessed using blood clearance and organ uptake of radiolabelled Escherichia coli. Transient ischaemia for 1 h did not alter Kupffer cell function in comparison with sham operation. However, prolonging arterial ischaemia for 2 h stimulated Kupffer cell function; both the phagocytic index and liver uptake of radiolabelled E. coli increased significantly (P < 0.01). Furthermore, this enhanced Kupffer cell activity was achieved each time the ischaemia was induced over a period of 5 days compared with repeated sham procedures (P < 0.05). Serum tumour necrosis factor (TNF) was significantly released after both single and repeated arterial occlusion for 2 h (P < 0.01). These observations show that transient arterial ischaemia enhances Kupffer cell function and induces TNF production.

Animals↗

PubMed1994

Influence of portal branch ligation on the outcome of repeat dearterializations of an experimental liver tumor in the rat.

It has been suggested that the portal vein should be occluded during intermittent hepatic dearterialization in order to induce a more complete ischemia of the tumor. In this experiment the influence of portal branch ligation in combination with repeat dearterializations on a liver tumor was investigated. Twenty-seven rats were randomly allocated to sham treatment (n = 6); portal branch ligation (PBL) (n = 7); 120 min of repeat dearterialization (n = 7); and portal branch ligation (PBL) in combination with 50 min of repeat dearterialization (n = 7) (once a day during 5 days). The results showed that portal branch ligation alone did not alter the tumor growth compared with sham treatment (P > 0.05), nor did portal branch ligation in combination with repeat dearterializations for 50 min (P > 0.05). However, tumor growth delay was achieved following 120 min of repeat dearterializations without occlusion of the portal branch (P < 0.01 versus all the other groups). There was a significant weight loss of the lobe undergoing PBL, whether dearterialization was added or not (P < 0.001). The liver nucleotide/DNA and RNA/DNA ratio significantly decreased as well. Histological examination showed that > 50% of tumor cells became necrotic after repeat dearterializations for 2 hr indicating a significant damage to tumor tissue. In contrast, PBL in combination with repeat dearterializations for 50 min induced extensive liver necrosis without having any influence on tumor growth.

Analysis of Variance↗

PubMed1994

Repeated dearterializations of an experimental liver tumor: short- and long-term results.

Intermittent dearterialization, as compared to permanent dearterialization, is preferably used in palliative ischemic treatment of liver tumors because collaterals seem to be avoidable. In this study the most efficient time period of hepatic arterial occlusion was assessed and short- and long-term effects of repeated daily dearterializations on the growth of a transplanted liver tumor was evaluated. In five groups of inbred Wistar/Furth rats bearing metastatic liver tumors the hepatic arterial circulation was repeatedly and transiently blocked for 0 (n = 8), 30 (n = 8), 60 (n = 8), 120 (n = 8), and 180 (n = 8) min daily for 5 days, respectively, with an implanted minioccluder. Another group (n = 6) was permanently dearterialized for 5 days. In addition, one group (n = 6) was intermittently dearterialized 120 min/day for 18 days and compared to the no treatment (n = 6) and permanent dearterialization (n = 6) groups. We found that repeated arterial occlusions for 120 and 180 min as well as permanent dearterialization for 5 days almost retarded the liver tumor growth completely. Collaterals developed in all rats subjected to permanent dearterialization and in one of the rats that were dearterialized repeatedly for 180 min. However, prolonged intermittent dearterializations for 180 days significantly delayed the tumor growth compared to permanent dearterialization (P < 0.05) yet collaterals did not develop. Therefore, we conclude that repeated arterial occlusions for 120 min are the optimal method of dearterialization that effectively retards the growth and prevents collateral circulation of this liver tumor. It may have implications in the palliative treatment of human liver tumor when dearterialization is considered.

Angiography↗

PubMed1994

Obstructive jaundice impairs reticuloendothelial function and promotes bacterial translocation in the rat.

Septic complications and renal insufficiency following biliary tract surgery are frequently seen in patients with obstructive jaundice. The precise mechanisms for understanding the susceptibility of the jaundiced patients to sepsis are, however, not clear. The present study aimed at investigating the influence of biliary obstruction on the reticuloendothelial function and bacterial translocation at various time intervals in the rat. Reticuloendothelial system (RES) function, as evaluated by measuring blood clearance of intravenously injected 125I-labeled Escherichia coli, and bacterial translocation were studied 3 days and 1, 2, and 3 weeks following either sham operation or common bile duct ligation (CBDL) and transection in the rat. RES function was significantly impaired and renal uptake of radiolabeled E. coli was significantly higher in jaundiced animals from Day 3 and on after CBDL (P < 0.01) concomitant with elevation of plasma levels of bilirubin and liver enzymes (P < 0.001) compared with their corresponding controls. The incidence of bacterial translocation 3 days and 1 and 2 weeks after biliary obstruction significantly increased (P < 0.05). We conclude that RES phagocytic function is impaired and the incidence of bacterial translocation is increased in jaundiced rats. These findings might contribute to explain the high susceptibility of postoperative septic complications and renal dysfunction in patients with obstructive jaundice.

Acute Kidney Injury↗