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Biomedical subjects

S Bengmark

Publications and source records attributed to S Bengmark.

At least 55 records · Page 3Linked to original sources
PubMed1993

The influence of surgically induced acute liver failure on the intestine in the rat.

The influence of acute liver failure induced by 90% hepatectomy on the intestine was evaluated in the rat. Small-intestinal mucosal mass decreased 2 h after hepatectomy. Microvillous height decreased significantly from 1 h and on, and villous height and area in the distal small intestine from 2 h after operation. Ninety per cent hepatectomy resulted in a decrease in systemic arterial blood pressure and an increase in portal venous pressure. Subserosal microcirculation and small-arterial circulation in the proximal and distal small intestine and colon decreased significantly after 90% hepatectomy. Overgrowth and colonization of Escherichia coli occurred in the distal small intestine from 1 h and on after hepatectomy. Protein content in enterocytes and bile secretion from the liver remnant were markedly reduced in hepatectomized rats. Thus, the present study shows evidence of alterations in intestinal morphology and function that can contribute to explain the enteric bacterial translocation after surgically induced acute liver failure.

Animals↗
PubMed1993

Modification of reticuloendothelial function by muramyl dipeptide-encapsulated liposomes in jaundiced rats treated with biliary decompression.

Rats with 2 weeks of biliary obstruction, with and without 1 week of concomitant biliary decompression relieving the jaundice, were treated with physiologic saline, free muramyl dipeptide (MDP), placebo liposomes, or liposome-encapsulated MDP. Reticuloendothelial system (RES) function was evaluated by blood clearance of intravenously injected 125I-labelled Escherichia coli. The corrected phagocytic index (alpha) after 1 week of biliary decompression returned to normal levels in animals treated with MDP liposomes, whereas RES function was impaired (P < 0.05) in all other jaundiced and biliary-decompressed groups. In the biliary-decompressed, MDP-liposome-treated group, hepatic uptake of radiolabelled bacteria was significantly higher (P < 0.05) and renal entrapment of bacteria was significantly lower (P < 0.05) than in all other jaundiced and biliary-decompressed groups. We conclude that treatment with MDP liposomes improves the otherwise impaired RES function in rats with biliary obstruction and biliary decompression.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1993

Gastroprotective capability of exogenous phosphatidylcholine in experimentally induced chronic gastric ulcers in rats.

Phosphatidylcholine (PC) is a main component of the hydrophobic gastric mucosal barrier. Exogenously administered, it prevents acute lesions. We evaluated the gastroprotective capacity of exogenous PC in both acute (ethanol- and indomethacin-induced) and chronic (indomethacin-induced) lesions in rats. Polyunsaturated (PPC) or hydrogenated PC in different concentrations were given intragastrically, before or after the injury factor, in single or repeated doses. Mucosal lesions were significantly reduced by a single dose of PPC, given before or after the injury factor, in both acute models. In the chronic model a single dose of PPC or hydrogenated PC significantly reduced lesions evaluated 6 h after ulcer induction, whereas after 72 h no protective effect was noticed. Repeated doses of PC were ineffective. In conclusion, in acute models exogenous PC reduces lesions in a dose-dependent manner and contributes to the mucosal defense. In chronic models an incomplete and temporary protection might be due to complex pathogenesis that requires activation of all levels in the mucosal defense. Strengthening of only one level was insufficient to restrict injury.

Animals↗
PubMed1993

The effect of exogenous administration of Lactobacillus reuteri R2LC and oat fiber on acetic acid-induced colitis in the rat.

The potential beneficial effect of exogenous administration of Lactobacillus on acetic acid-induced colitis was evaluated in the rat. Colitis was induced by instillation of 4% acetic acid for 15 sec in an exteriorized colonic segment. This produced uniform colitis with a threefold increase in myeloperoxidase (MPO) activity of the colonic tissue (an index of neutrophil infiltration) and a sixfold increase in plasma exudation into the lumen of the colon (mucosal permeability) as evaluated 4 days after acetic acid administration. Intracolonic administration of L. reuteri R2LC immediately after acetic acid administration, at a dose of 5 ml of 7 x 10(7) colony-forming units (CFU)/ml in two forms: either as pure bacterial suspension or as fermented oatmeal soup, prevented the development of colitis. Thus, the morphologic score, MPO activity, and mucosal permeability were almost normalized by Lactobacillus treatment. Initiating the treatment 24 h after acetic acid administration or using lower doses of 1 ml for 3 consecutive days resulted in a smaller protective effect. We conclude that exogenous administration of L. reuteri R2LC prevents the development of acetic acid-induced colitis in the rat.

Acetates↗
PubMed1993

Enteric bacterial translocation after intraperitoneal implantation of rubber drain pieces.

To study the kinetics and mechanisms of bacterial translocation from the gut after intraperitoneal (IP) implantation of prosthetic materials, different sizes of rubber drain pieces were intraperitoneally implanted in the rat, followed by evaluation of ileal mucosal permeability after 2 days and of the occurrence of bacterial translocation and gut oxygen extraction at various time points. Enteric bacteria translocated to mesenteric lymph nodes and disseminated to systemic organs (liver, spleen, lungs, and kidneys), the portal vein, and inferior vena cava 2, 4, and 6 h after IP implantation of rubber drain pieces with 10-, 7-, and 3-cm2 areas, respectively, and subsequently to the IP rubber drain piece and the peritoneal cavity on the 2nd postoperative day. The incidence of translocation correlated with the size of the implanted material and time after implantation. The gut oxygen extraction increased significantly after IP implantation of 7- and 10-cm2 rubber drain pieces. The ileal mucosal permeability was enhanced in the groups implanted with 7- and 10-cm2 drain pieces. Thus, bacterial translocation occurs already in the early period after IP implantation of rubber drain and increased with time. The increased gut oxygen extraction implies that the gut is susceptible to IP inflammatory stimulation, and the enhanced ileal permeability suggests that the integrity of the gastrointestinal tract is compromised, which might facilitate bacterial translocation.

Animals↗
PubMed1993

Green banana protection of gastric mucosa against experimentally induced injuries in rats. A multicomponent mechanism?

The protective capacities of fresh green (unripe) sweet bananas and of phosphatidylcholine and pectin (banana ingredients) against acute (ethanol- or indomethacin-induced) and chronic (indomethacin-induced) gastric mucosal lesions were evaluated in rats. Banana pulp was mixed with saline and given by gavage, as a pretreatment in a single dose. The identical protocol was used for pectin and phosphatidylcholine solution, and the dosages were adjusted to equal the amount of ingredients in the banana mixture, but higher concentrations were also given. The banana suspension reduced acute lesions, as did pectin and phosphatidylcholine in higher concentrations, but in concentrations as in fresh fruit no protective effects were observed except by pectin against indomethacin injury. In the model of chronic ulcers the banana suspension provided an incomplete and temporary protective effect. We conclude that the protective capacity of fresh green sweet bananas cannot be confined to only one active component. Pectin and phosphatidylcholine may protect gastric mucosa by strengthening the mucous-phospholipid layer, but the mechanism of protection afforded by bananas has to be further elucidated.

Acute Disease↗
PubMed1993

Intramucosal pH and oxygen extraction in the gastrointestinal tract after major liver resection in rats.

OBJECTIVE: To assess the influence of 70% and 90% liver resection on oxygen extraction and intramucosal and intraluminal pH in the gastrointestinal tract in rats. DESIGN: Random control trial. MATERIAL: 63 adult male Sprague-Dawley rats. INTERVENTIONS: Laparotomy with separation of liver from surrounding tissue (sham operation), 70% hepatectomy, or 90% hepatectomy (n = 21 in each group). At 1, 2, and 4 hours (n = 7/timepoint), the animals in each of the three groups had the following variables studied: intestinal oxygen delivery; blood gas analysis of arterial, caval, and portal venous blood; and direct intraluminal pH together with indirect measurements of intramucosal pH of the gastrointestinal tract. RESULTS: There was a temporary increase in the pH of arterial blood two hours after 70% hepatectomy. There was a reduction in intramucosal pH after 90% hepatectomy which started two hours after operation and became significant at four hours. The intraluminal pH of the gastrointestinal tract was increased two and four hours after both 70% and 90% hepatectomy, compared with the sham operated group. Systemic oxygen extraction increased immediately after hepatectomy. Gastrointestinal oxygen extraction increased gradually in the rats that had undergone 70% hepatectomy, but was reduced in those subjected to 90% hepatectomy. CONCLUSIONS: Major liver resection induces alterations in both systemic and gut physiology. These may go some way towards explaining the disturbances in enteric bacterial ecology, the increase in bacterial adherence on the surface of the intestine, and the translocation of bacteria from the gut, after major liver resection in rats.

Animals↗
PubMed1993

New model of reversible obstructive jaundice in rats.

OBJECTIVE: To develop a simple, reversible, reproducible model of obstructive jaundice in rats that could also be used for studies of infection associated with foreign bodies in the biliary tract. DESIGN: Open study. SETTING: University of Lund, Sweden. MATERIAL: 18 Male Sprague-Dawley rats. INTERVENTION: Laparotomy and the placing of a "minioccluder" (developed in this laboratory) around the common bile duct. This was left in place for five days. MAIN OUTCOME MEASURES: Results of standard liver function tests measured on days 0, 5, and 12; the degree of obstruction seen on cholangiography on day 12; and changes in body weight on days 5 and 12. RESULTS: Activities of hepatic enzymes and plasma bilirubin concentrations were significantly increased on day 5 compared with day 0 (p < 0.01 in each case), but had returned to the reference range by day 12. Cholangiography (n = 10) showed that even though the part of the common bile duct proximal to the minioccluder was dilated the distal part was of normal diameter and patent. By 5 days the animals had lost 5% of their mean body weight, but this increased by 8% during the 7 days after relief of the occlusion (day 12). CONCLUSION: We have developed a reversible, reproducible model of obstructive jaundice in rats, which can be used for the study of topics related to obstructive jaundice and in particular infection associated with foreign bodies in the biliary tract.

Animals↗
PubMed1993

Morphological response of the peritoneum and spleen to intraperitoneal biomaterials.

The present study was performed to evaluate the morphological response of the peritoneum and spleen to biomaterials. Silicone elastomer, knitted dacron or rubber was implanted, respectively, into a rat's peritoneal cavity and the morphology of the peritoneum and spleen was studied at 4 hours and on the 1st, 4th, 7th and 21st day after surgery. The morphological changes were identical among groups with different implanted materials. After intraperitoneal implantation of biomaterials from 4 hours and on, an infiltration of inflammatory cells was found in the slackened edematous superficial part of the peritoneum. Also noted in the spleen were stasis, vessel dilatation and fibrin deposition. With the help of scanning electron microscopy, a marked denudation and separation of the mesothelial cells, with infiltration of inflammatory cells, were observed. Peripheral leucocytes significantly increased in number one day after intraperitoneal implantation. Three weeks after intraperitoneal implantation, the materials were completely encapsulated and the morphological aberration of the peritoneum and spleen disappeared. The findings reveal the consequence and the resolution of the host-biomaterial interaction, which could contribute to the explanation of various pathophysiological alterations, including the translocation of enteric bacteria and the development of infectious complications after intraperitoneal biomaterial implantation.

Animals↗
PubMed1993

Bacterial translocation and reticuloendothelial function after implantation of abdominal drainage in the rat.

Bacterial translocation and reticuloendothelial system (RES) function were measured in the rat after intraperitoneal (IP) implantation of rubber drain pieces (7.5 cm2). Six hours after implantation, enteric bacterial translocation was noted to mesenteric lymph nodes (MLNs), the liver, spleen, lungs, kidneys and portal and caval vein blood. RES function was evaluated in terms of blood clearance and organ uptake of intravenously injected 125I-labelled, heat-killed E. coli. A significant elevation of corrected phagocytic index (alpha) was found 24 hours after IP implantation. Localization of 125I-labeled E. coli was significantly enhanced in systemic organs (kidneys, spleen, liver and lungs) 24 hours after IP implantation, whereas it was locally impaired (MLNs and proximal jejunum) 6 hours after IP implantation and thereafter. An inverse correlation between the localization of radiolabelled E. coli in the liver, spleen and lungs and the incidence of bacterial translocation to these organs was found. The results suggest that an association exists between alterations in RES function and bacterial translocation in the early course following IP implantation of rubber drains.

Abdomen↗
PubMed1993

Bioreduction of RSU 1069 and mitomycin C after dearterialization.

RSU 1069 (1-(2-nitro-1-imidazolyl)-3-(1-aziridinyl)-2-propanol) and Mitomycin C (MMC) have both been shown to be directly cytotoxic to hypoxic cells. Repeat and transient dearterializations of a liver tumour would cause its cells to become intermittently hypoxic. In this experiment the therapeutic gain of RSU 1069 and MMC was evaluated when combined with either a single or repeat dearterializations of a transplanted liver tumour. The tumour growth during the first 6 days was significantly delayed when the administration of RSU 1069 (40 mg kg-1, i.p.) was followed 15 minutes later by a single dearterialization for 2 hours compared with sham operation (P = 0.0369) or either treatment alone (P = 0.0142 vs RSU 1069 alone and P = 0.0031 vs a single dearterialization for 2 hours alone). Furthermore, RSU 169 administered 15 min prior to a single dearterialization for 2 hours is more effective to retard tumour growth than MMC either alone (P = 0.0198) or with the same period of dearterialization (P = 0.0326). Repeat dearterializations (2 hours/day) during 5 days effectively retarded the growth of the tumour by itself (P = 0.015 vs sham operation). A larger growth delay was obtained when RSU 1069 was administered 15 min before the first dearterialization (P = 0.009 vs sham operation), though the growth delay between those two groups was not significant (P = 0.07). Survival time was significantly prolonged when repeat dearterializations were combined with RSU 1069 (P = 0.007 vs sham operation; P = 0.0009 vs RSU 1069 and P = 0.003 vs repeat dearterialization alone).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Inhibitory effect of 2-deoxy-D-glucose on liver tumor growth in rats.

Since tumor cells are more dependent on glycolysis for energy supply than other cells, we tested whether its inhibition by 2-deoxy-D-glucose (2-DG) affects tumor growth. Male Wistar rats were inoculated in the liver with tumor cells from a chemically induced colonic adenocarcinoma. From day 5 after inoculation 2-DG (400 mg/kg/24 h) was continuously infused into the hepatic artery for 5 days; controls received saline in the same fashion. Seven days after the end of infusion, the animals were sacrificed. A second experimental group of rats was treated with isolated liver perfusion for 30 min with oxygenated blood through the portal vein and hepatic artery simultaneously. In the perfusate, 400 mg/kg 2-DG were added, and the rats were sacrificed at 10 days after perfusion. A first control group underwent perfusion without 2-DG, and a second control group received i.v. infusion of 2-DG (400 mg/kg/30 min) for 30 min over 5 days. A nontreated control group was also added. All animals survived the procedures. The concentration of blood glucose increased in the rats receiving 2-DG i.v. and intraarterially but was unchanged in the other groups. The tumor growth was significantly reduced by 2-DG in all experimental groups, with no difference between the groups. It is therefore concluded that 2-DG is of potential interest in the treatment of malignancies. Since local application of 2-DG avoids the risk for systemic side effects, this approach should be explored further.

Animals↗
PubMed1992

Bacterial translocation after major hepatectomy in patients and rats.

Bacterial infections are frequent complications after liver resection. Of 138 patients who underwent major hepatectomy, 11 patients (8%) developed intra-abdominal sepsis in the postoperative period. Seven bacterial strains of gut origin were isolated from the abdominal cavity. Eight patients had multiple bacteria cultured. In the experimental studies on rat models, positive mesenteric lymph node cultures were seen 2 hours after removal of 70% and 90% of the total weight of the rat liver, and 12 hours after 50% hepatectomy, persisting for 3 and 4 days after 50% and 70% hepatectomy, respectively. The incidences of bacteremia 2 and 4 hours after 90% hepatectomy were 80% and 100%, respectively; 6 hours after 70% liver resection, the incidence of bacteremia was 33%. Blood cultures were positive in only 6% of the rats following 50% hepatectomy, and in none of the controls. Thus, bacterial translocation occurs in the early course after hepatectomy, the incidence being proportional to the amount of liver tissue removed.

Abdomen↗
PubMed1992

Effect of phosphatidylcholine on postoperative adhesions after small bowel anastomosis in the rat.

The possibility of preventing postoperative adhesions using phosphatidylcholine (PC) was studied in rats. A small bowel anastomosis was created using continuous or interrupted 5/0 silk sutures. Adhesions were measured by recording the maximal length of adhesions around the anastomosis and the number of organs involved in the adhesions. PC was administered intraperitoneally either as a single dose or as three separate doses. Postoperative adhesions developed in all animals; the degree of adhesion was independent of the suture technique used. PC given once at a dose of 20 mg significantly decreased adhesion formation (P less than 0.01). The mechanism underlying this effect may be that the exogenous PC provides a lubricant layer replacing endogenous hydrolysed phospholipid. The result with repeated PC administration was not different from that after a single dose. Increasing the single dose of PC to 40 or 60 mg resulted in anastomotic dehiscence and subsequent peritonitis. It is concluded that PC in a single dose of 20 mg reduces adhesion formation after small bowel anastomosis in the rat.

Anastomosis, Surgical↗
PubMed1992

Effect of biliary decompression on reticuloendothelial function in jaundiced rats.

The recovery of reticuloendothelial system (RES) function following decompression of obstructive jaundice was studied using a rat model with bile duct ligation and side-to-side choledochoduodenostomy. Histopathological changes in the liver were still present 5 weeks after relief of jaundice, while results of liver function tests had returned to normal. RES function evaluated by the blood clearance and organ uptake of radiolabelled Escherichia coli using a corrected phagocytic index gradually returned to normal following biliary decompression. The severely impaired RES activity noted 1 week after operation may explain the increased incidence of sepsis and renal insufficiency in the early period after biliary surgery in jaundiced patients.

Animals↗
PubMed1992

Endothelialization of microporous polytetrafluoroethylene grafts in the infrarenal aorta and caval vein of the rat.

To study healing and endothelialization of vascular grafts, microporous polytetrafluoroethylene (PTFE) prostheses 2 mm in inner diameter and 5 mm long were implanted into the infrarenal aorta or caval vein of the rat. Patency was assessed in six rats from each group at days 3, 7, 14, 28, and 56 after implantation. Four grafts were occluded, two in the aorta (56 days) and two in the caval vein (3 and 14 days). The prostheses were examined via scanning electron and light microscopy for evaluation of endothelialization. At 3 days, the inner surface of the aortic grafts was covered by a plasma proteinaceous layer and that of the caval vein grafts by a thin mural thrombus. Endothelial cells then migrated from aorta/caval vein edges over the graft. At 14 days, the caval vein grafts were completely re-endothelialized, and, at 28 days, the mural thrombus in these grafts was replaced by neointima. In contrast, endothelialization of the aortic grafts had advanced only 1 mm at about 56 days, never forming a complete endothelial layer. We conclude that endothelialization of microporous PTFE prostheses is more rapid and complete in the caval vein than in the aorta of the rat.

Animals↗
PubMed1992

Effect of fermented oatmeal soup on the cholesterol level and the Lactobacillus colonization of rat intestinal mucosa.

Rats were fed with freeze-dried oatmeal soup fermented by six different Lactobacillus strains from rat and man; the formula is intended for enteral feeding. The serum cholesterol levels after 10 d were lower for rats eating oatmeal as compared to a commercial product, Biosorb Sond. Colonizing ability of the administered strains were evaluated in vivo. Only Lactobacillus reuteri R21c were able to, effectively, colonizing the mucosa; it represented about 30% of the Lactobacillus population 24 d after termination of the administration. L. reuteri R21c was easily recognized by the ability to produce a yellow pigment on agar plates. The identity was confirmed by carbohydrate fermentations (API 50CH), plasmid pattern and endonuclease restriction analysis of the chromosomal DNA.

Animals↗