37 results on '"Franzén LE"'
Search Results
2. Augmented increase in tight junction permeability by luminal stimuli in the non-inflamed ileum of crohn's disease
- Author
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Söderholm, Johan D, Olaison, Gunnar, Peterson, KH, Franzén, LE, Lindmark, T, Wirén, Mikael, Tagesson, Christer, Sjödahl, Rune, Söderholm, Johan D, Olaison, Gunnar, Peterson, KH, Franzén, LE, Lindmark, T, Wirén, Mikael, Tagesson, Christer, and Sjödahl, Rune
- Abstract
Background: Crohn's disease is associated with deranged intestinal permeability in vivo, suggesting dysfunction of tight junctions. The luminal contents are important for development of neoinflammation following resection. Regulation of tight junctions by luminal factors has not previously been studied in Crohn's disease. Aims: The aim of the study was to investigate the effects of a luminal stimulus, known to affect tight junctions, on the distal ileum in patients with Crohn's disease. Patients: Surgical specimens from the distal ileum of patients with Crohn's disease (n=l 2) were studied, and ileal specimens from colon cancer patients (n=l 3) served as controls. Methods: Mucosal permeability to 51Cr-EDTA and electrical resistance were studied in Ussing chambers during luminal exposure to sodium caprate (a constituent of milk fat, affecting tight junctions) or to buffer only. The mechanisms involved were studied by mucosal ATP levels, and by electron and confocal microscopy. Results: Baseline permeability was the same in non-inflamed ileum of Crohn's disease and controls. Sodium caprate induced a rapid increase in paracellular permeability - that is, increased permeation of 51Cr-EDTA and decreased electrical resistance - which was more pronounced in non-inflamed ileum of Crohn's disease, and electron microscopy showed dilatations within the tight junctions. Moreover, sodium caprate induced disassembly of perijunctional filamentous actin was more pronounced in Crohn's disease mucosa. Mucosal permeability changes were accompanied by mitochondrial swelling and a fall in epithelial ATP content, suggesting uncoupling of oxidative phosphorylation. Conclusions: The tight junctions in the non-inflamed distal ileum of Crohn's disease were more reactive to luminal stimuli, possibly mediated via disturbed cytoskeletal contractility. This could contribute to the development of mucosal neoinflammation in Crohn's disease.
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- 2002
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3. The clinical significance of slightly to moderately increased liver transaminase values in asymptomatic patients.
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Mathiesen, UL, Franzén, LE, Frydén, Aril, Foberg, U, Bodemar, Göran, Mathiesen, UL, Franzén, LE, Frydén, Aril, Foberg, U, and Bodemar, Göran
- Published
- 1999
4. Low clinical relevance of the nonalcoholic fatty liver disease activity score (NAS) in predicting fibrosis progression.
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Ekstedt M, Franzén LE, Mathiesen UL, and Kechagias S
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- Adult, Aged, Biopsy, Fatty Liver complications, Fatty Liver diagnosis, Female, Humans, Liver Cirrhosis complications, Logistic Models, Male, Middle Aged, Multivariate Analysis, Non-alcoholic Fatty Liver Disease, Predictive Value of Tests, Severity of Illness Index, Disease Progression, Fatty Liver pathology, Liver pathology, Liver Cirrhosis pathology
- Abstract
Background/aims: The nonalcoholic fatty liver disease (NAFLD) activity score (NAS) is a newly proposed system to grade the necroinflammatory activity in liver biopsies of NAFLD patients. This study evaluates the usefulness of the NAS in predicting clinical deterioration and fibrosis progression in NAFLD., Methods: One hundred and twenty-nine patients with biopsy-proven NAFLD were included in a long-term histological follow-up study. Clinical course and change in fibrosis stage were compared between nonalcoholic steatohepatitis (NASH), "borderline NASH," and "not NASH" patients. Significant fibrosis progression was defined as progression of more than one fibrosis stage or development of end-stage liver disease during follow-up., Results: Eighty-eight patients accepted reevaluation and 68 underwent repeat liver biopsy. Mean time between biopsies was 13.8 ± 1.2 years (range 10.3-16.3). At baseline, NASH was diagnosed in 2 (1.6%) patients, and at follow-up, in 1 (1.5%) patient. A trend toward higher baseline NAS was seen in patients (n = 7) who developed end-stage liver disease (3.1 ± 0.9 vs. 2.2 ± 1.0; p = 0.050). Baseline NAS was associated with progressive disease in a univariate binary logistic regression analysis (p = 0.024), but no difference was seen in the multivariate analysis including the NAS, portal inflammation, and perisinusoidal fibrosis. Moreover, 18% of patients without NASH progressed significantly in fibrosis stage., Conclusions: The ability of the NAS to predict progression of NAFLD is poor. The clinical usefulness of the score is limited due to the significant overlap in clinical development between NAS score groups. To use the NAS as endpoint in treatment trial is not justified.
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- 2012
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5. Nonselective matrix metalloproteinase but not tumor necrosis factor-α inhibition effectively preserves the early critical colon anastomotic integrity.
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Ågren MS, Andersen TL, Andersen L, Schiødt CB, Surve V, Andreassen TT, Risteli J, Franzén LE, Delaissé JM, Heegaard AM, and Jorgensen LN
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- Anastomosis, Surgical, Animals, Colon pathology, Dipeptides pharmacology, Extracellular Space drug effects, Extracellular Space enzymology, Male, Matrix Metalloproteinases metabolism, Organic Chemicals pharmacology, Rats, Rats, Sprague-Dawley, Tumor Necrosis Factor-alpha metabolism, Colon drug effects, Colon surgery, Matrix Metalloproteinase Inhibitors, Protease Inhibitors pharmacology, Protein Kinase Inhibitors pharmacology, Tumor Necrosis Factor-alpha antagonists & inhibitors
- Abstract
Background: Increased matrix metalloproteinase (MMP) activity has been implicated in the pathogenesis of colorectal anastomotic leakage. Tumor necrosis factor-α (TNF-α) induces MMPs and may influence anastomosis repair., Methods: We assessed the efficacies of the nonselective hydroxamate MMP inhibitor GM6001, the selective hydroxamate MMP inhibitor AG3340 and a TNF-α antagonist with respect to anastomotic breaking strength of left-sided colon anastomoses in male Sprague-Dawley rats., Results: Systemic GM6001 treatment effectively blocked MMP activity and maintained the initial breaking strength day 0 of the anastomoses when administered subcutaneously as daily depositions (100 mg/kg) or continuously (10 mg/kg/day). In contrast, the anastomotic biomechanic strength was lowered by 55% (p < 0.001) in vehicle-treated rats on postoperative day 3. GM6001 treatment increased breaking strength by 88% (p < 0.0005) compared with vehicle-treated rats day 3 and reduced (p = 0.003) the occurrence of spontaneous anastomotic dehiscence. Histologically, the anastomotic wound was narrower (p < 0.05) in the longitudinal direction in GM6001-treated animals whereas GM6001 had no significant effect on inflammatory cell infiltration or epithelialization. AG3340 (10 mg/kg) increased (p < 0.012) breaking strength by 47% compared with vehicle on day 3 but did not significantly prevent the reduction of the initial breaking strength on day 0. Although the increased TNF-α levels in the wound were attenuated, the anastomotic breaking strength was not improved (p = 0.62) by the TNF-α (10 mg/kg) inhibitor given systemically., Conclusions: Pharmacological nonselective MMP inhibition ought to be explored as a prophylactic regimen to reduce anastomotic complications following colorectal resection. The involvement of TNF-α was insignificant in anastomotic wound healing in an experimental model.
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- 2011
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6. Characterization of the gastric cardia in volunteers from the general population. Type of mucosa, Helicobacter pylori infection, inflammation, mucosal proliferative activity, p53 and p21 expression, and relations to gastritis.
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Petersson F, Franzén LE, and Borch K
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- Adult, Aged, Cell Proliferation, Chronic Disease, Female, Gastritis metabolism, Gastritis microbiology, Gastroscopy, Helicobacter Infections metabolism, Humans, Inflammation, Ki-67 Antigen analysis, Male, Middle Aged, Cardia pathology, Gastric Mucosa pathology, Gastritis pathology, Helicobacter Infections pathology, Helicobacter pylori, Proto-Oncogene Proteins p21(ras) metabolism, Tumor Suppressor Protein p53 analysis
- Abstract
The aim of this research was to characterize the mucosa of the gastric cardia in relation to infection with Helicobacter pylori and the occurrence of chronic gastritis in other parts of the stomach in a sample of the general population. In this study, 80 adult volunteers underwent esophagogastroscopy with biopsies from the gastric cardia, corpus, and antrum. Gastritis was classified according to the Sydney system. Chronic gastritis (cardia excepted) was diagnosed in 35 subjects, 30 with H. pylori infection. Epithelial proliferative activity (Ki-67), p53- and p21 expression were examined quantitatively with cell counting after immunohistochemical stainings. Esophagitis was diagnosed macroscopically. Fourty eight subjects had cardia-type and 32 corpus-type mucosa in the anatomical cardia. The prevalence of esophagitis (nine cases) did not differ between these groups. Carditis was more prevalent among subjects with cardia-type mucosa (73 vs. 28%, P < 0.0001). H. pylori was present in 48% of those with cardia-type and 25% of those with corpus-type mucosa (P = 0.06). Of the 44 subjects with carditis, 31 had H. pylori in this location. The group with H. pylori infection had significantly higher mucosal proliferative activity when compared to uninfected subjects. Among the subjects with H. pylori-associated carditis, more p53-positive epithelial cells were detected compared to both the non-infected group (P = 0.0004) and to subjects with non-H. pylori-associated carditis (P = 0.03). In subjects with cardia-type mucosa, and both carditis and gastritis, the degree of chronic inflammation was higher in the cardia compared to the corpus and antrum and the p53 expression was significantly higher in the cardia compared to the corpus, but similar to that in the antrum. The proliferative activity was significantly higher in the antrum compared to the cardia and corpus, respectively. In conclusion, H. pylori infection, carditis, and increased p53 expression are more common in subjects with cardia- than corpus-type mucosa in the gastric cardia. Carditis is mainly related to H. pylori infection. There are some differences regarding inflammation, proliferative activity, and p53 expression between the cardia and other regions of the stomach, yet the significance of these differences remains to be clarified.
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- 2010
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7. A morphometric study of antral G-cell density in a sample of adult general population: comparison of three different methods and correlation with patient demography, helicobacter pylori infection, histomorphology and circulating gastrin levels.
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Petersson F, Borch K, Rehfeld JF, and Franzén LE
- Abstract
Helicobacter pylori infection has been linked to hypergastrinemia and either decreased or normal G-cell content in the antral mucosa. To clarify this controversial issue, we quantitatively determined antral G-cell content on the same biopsy specimens with three different methods and examined whether these methods are intercorrelated and the relation of these methods to plasma gastrin concentrations, demography, the occurrence of H. pylori infection and chronic gastritis. Gastric antral mucosal biopsy sections from 273 adults (188 with and 85 without H pylori infection) from a general population sample were examined immunohistochemically for G-cells using cell counting, stereology (point counting) and computerized image analysis. Gastritis was scored according to the updated Sydney system. Basal plasma gastrin concentrations were measured by radioimmunoassay. The three methods for G-cell quantification were poorly correlated and the results showed no correlation with basal plasma gastrin concentrations. The antral G-cell density and scores for H. pylori colonization were positively related to age. Neither the scores for chronic inflammation, nor the scores for inflammatory activity, atrophy or intestinal metaplasia were consistently related to the antral G-cell content. In conclusion, the results of three techniques for G-cell quantification in the gastric antral mucosa were poorly intercorrelated and none of the methods correlated with plasma gastrin concentrations. Age and scores for H pylori colonization seem to be determinants of the G-cell density. That common morphometric techniques correlate poorly is of utmost importance to bear in mind when quantitative morphological studies are planned, compared or interpreted.
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- 2009
8. Alcohol consumption is associated with progression of hepatic fibrosis in non-alcoholic fatty liver disease.
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Ekstedt M, Franzén LE, Holmqvist M, Bendtsen P, Mathiesen UL, Bodemar G, and Kechagias S
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- Alanine Transaminase blood, Alkaline Phosphatase blood, Aspartate Aminotransferases blood, Biopsy, Chi-Square Distribution, Disease Progression, Fatty Liver enzymology, Fatty Liver pathology, Female, Humans, Liver Cirrhosis enzymology, Liver Cirrhosis pathology, Liver Function Tests, Male, Middle Aged, Statistics, Nonparametric, Alcohol Drinking adverse effects, Fatty Liver complications, Liver Cirrhosis etiology
- Abstract
Objective: Moderate alcohol consumption has been reported to be inversely associated with cardiovascular disease and total mortality. The importance of non-alcoholic fatty liver disease (NAFLD) is increasing and many NAFLD patients suffer from cardiovascular disease. In these patients, moderate alcohol consumption could be beneficial. The aim of this study was to investigate whether low alcohol intake, consistent with the diagnosis of NAFLD, is associated with fibrosis progression in established NAFLD., Material and Methods: Seventy-one patients originally referred because of chronically elevated liver enzymes and diagnosed with biopsy-proven NAFLD were re-evaluated. A validated questionnaire combined with an oral interview was used to assess weekly alcohol consumption and the frequency of episodic drinking. Significant fibrosis progression in NAFLD was defined as progression of more than one fibrosis stage or development of endstage liver disease during follow-up., Results: Mean follow-up (SD) was 13.8 (1.2) years between liver biopsies. At follow-up, 17 patients (24%) fulfilled the criteria for significant fibrosis progression. The proportion of patients reporting heavy episodic drinking at least once a month was higher among those with significant fibrosis progression (p=0.003) and a trend towards higher weekly alcohol consumption was also seen (p=0.061). In a multivariate binary logistic regression analysis, heavy episodic drinking (p<0.001) and insulin resistance (p<0.01) were independently associated with significant fibrosis progression., Conclusions: Moderate alcohol consumption, consistent with the diagnosis of NAFLD to be set, is associated with fibrosis progression in NAFLD. These patients should be advised to refrain from heavy episodic drinking.
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- 2009
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9. Probiotics enhance pancreatic glutathione biosynthesis and reduce oxidative stress in experimental acute pancreatitis.
- Author
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Lutgendorff F, Trulsson LM, van Minnen LP, Rijkers GT, Timmerman HM, Franzén LE, Gooszen HG, Akkermans LM, Söderholm JD, and Sandström PA
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- Animals, Apoptosis drug effects, Ceruletide, Glycodeoxycholic Acid, Male, Pancreatitis chemically induced, Rats, Rats, Sprague-Dawley, Specific Pathogen-Free Organisms, Glutathione biosynthesis, Oxidative Stress drug effects, Pancreatitis drug therapy, Pancreatitis metabolism, Probiotics pharmacology
- Abstract
Factors determining severity of acute pancreatitis (AP) are poorly understood. Oxidative stress causes acinar cell injury and contributes to the severity, whereas prophylactic probiotics ameliorate experimental pancreatitis. Our objective was to study how probiotics affect oxidative stress, inflammation, and acinar cell injury during the early phase of AP. Fifty-three male Sprague-Dawley rats were randomly allocated into groups: 1) control, 2) sham procedure, 3) AP with no treatment, 4) AP with probiotics, and 5) AP with placebo. AP was induced under general anesthesia by intraductal glycodeoxycholate infusion (15 mM) and intravenous cerulein (5 microg.kg(-1).h(-1), for 6 h). Daily probiotics or placebo were administered intragastrically, starting 5 days prior to AP. After cerulein infusion, pancreas samples were collected for analysis including lipid peroxidation, glutathione, glutamate-cysteine-ligase activity, histological grading of pancreatic injury, and NF-kappaB activation. The severity of pancreatic injury correlated to oxidative damage (r = 0.9) and was ameliorated by probiotics (1.5 vs. placebo 5.5; P = 0.014). AP-induced NF-kappaB activation was reduced by probiotics (0.20 vs. placebo 0.53 OD(450nm)/mg nuclear protein; P < 0.001). Probiotics attenuated AP-induced lipid peroxidation (0.25 vs. placebo 0.51 pmol malondialdehyde/mg protein; P < 0.001). Not only was AP-induced glutathione depletion prevented (8.81 vs. placebo 4.1 micromol/mg protein, P < 0.001), probiotic pretreatment even increased glutathione compared with sham rats (8.81 vs. sham 6.18 miccromol/mg protein, P < 0.001). Biosynthesis of glutathione (glutamate-cysteine-ligase activity) was enhanced in probiotic-pretreated animals. Probiotics enhanced the biosynthesis of glutathione, which may have reduced activation of inflammation and acinar cell injury and ameliorated experimental AP, via a reduction in oxidative stress.
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- 2008
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10. Characterization of colon carcinoma growth pattern by computerized morphometry: definition of a complexity index.
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Franzén LE, Hahn-Strömberg V, Edvardsson H, and Bodin L
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- Cell Proliferation, Cluster Analysis, Fractals, Humans, Immunohistochemistry, Colonic Neoplasms pathology, Image Processing, Computer-Assisted methods
- Abstract
The invasive front of carcinomas may vary in complexity from smooth to highly complex when the front splits up into small cell clusters or even single cancer cells. The degree of complexity is usually estimated visually and semiquantitatively by a pathologist, although more objective methods based on computer-assisted image analysis are available. In this study, we compared the visual estimation of the irregularity of the tumour invasion front of colon carcinomas to different quantitative image analytical techniques and defined a complexity index for the invasive margin. Sections from 29 archived colon carcinomas were stained immunohistochemically for cytokeratin 8. Images of the tumour invasion front were read into a computer and thresholded so that the tumour tissue became black and the background white or so that the tumour front was outlined by a single pixel line. The invasive front was visually classified into four degrees of irregularity by a pathologist. The complexity of the front was then assessed using four different image analysis techniques, i.e. the estimation of fractal dimension, tumour front length, number of tumour cell clusters and lacunarity. Fractal dimension and tumour cell clusters together gave the best correlation to visual grading using a discriminant analysis. A cluster analysis and a tree diagram analysis were then performed and were found to be superior to visual estimation. The clusters represent different degrees of complexity and the result of the tree diagram analysis can be used to assign complexity indices to colon tumours. The fractal dimension separated tumours up to a certain level (1.5-1.6) of complexity. When the tumour front split up into small cell clusters, the counting of tumour cell clusters separated the cells over and above the fractal dimension. This new technique can be used to objectively and quantitatively describe the complexity of the invasive front of tumours.
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- 2008
11. Statins in non-alcoholic fatty liver disease and chronically elevated liver enzymes: a histopathological follow-up study.
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Ekstedt M, Franzén LE, Mathiesen UL, Holmqvist M, Bodemar G, and Kechagias S
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- Adult, Enzymes blood, Fatty Liver drug therapy, Female, Follow-Up Studies, Humans, Hydroxymethylglutaryl-CoA Reductase Inhibitors therapeutic use, Liver drug effects, Male, Middle Aged, Fatty Liver enzymology, Fatty Liver pathology, Hydroxymethylglutaryl-CoA Reductase Inhibitors adverse effects, Liver enzymology, Liver pathology
- Abstract
Background/aims: The effect of statins on hepatic histology in non-alcoholic fatty liver disease (NAFLD) is not known. This study explores hepatic histology in NAFLD patients before and after initiation of statin therapy and compares histological outcome with NAFLD patients who had not been prescribed statins., Methods: Sixty-eight NAFLD patients were re-evaluated. Follow-up ranged from 10.3 to 16.3 years. Subjects were clinically investigated and a repeat liver biopsy was obtained. No patient was taking statins at baseline while 17 patients were treated with statins at follow-up., Results: At baseline, patients that later were prescribed statins had significantly higher BMI and more pronounced hepatic steatosis. At follow-up patients on medication with statins continued to have significantly higher BMI. Diabetes was significantly more common among patients on medication with statins and they had significantly more pronounced insulin resistance. However, they exhibited a significant reduction of liver steatosis at follow-up as opposed to patients not taking statins. Despite exhibiting a high risk profile for progression of liver fibrosis, only four patients on statin treatment progressed in fibrosis stage., Conclusions: Statins can be prescribed in patients with elevated liver enzymes because of NAFLD.
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- 2007
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12. Long-term follow-up of patients with NAFLD and elevated liver enzymes.
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Ekstedt M, Franzén LE, Mathiesen UL, Thorelius L, Holmqvist M, Bodemar G, and Kechagias S
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- Alkaline Phosphatase blood, Cohort Studies, Disease Progression, Fatty Liver enzymology, Fatty Liver pathology, Female, Follow-Up Studies, Humans, Liver pathology, Male, Middle Aged, Prognosis, Survival Rate, Transaminases blood, Cardiovascular Diseases mortality, Fatty Liver mortality, Liver Diseases mortality
- Abstract
Nonalcoholic fatty liver disease (NAFLD) is the most common cause of elevated liver enzymes in patients of developed countries. We determined the long-term clinical and histological courses of such patients. In a cohort study, 129 consecutively enrolled patients diagnosed with biopsy-proven NAFLD were reevaluated. Survival and causes of death were compared with a matched reference population. Living NAFLD patients were offered repeat liver biopsy and clinical and biochemical investigation. Mean follow-up (SD) was 13.7 (1.3) years. Mortality was not increased in patients with steatosis. Survival of patients with nonalcoholic steatohepatitis (NASH) was reduced (P = .01). These subjects more often died from cardiovascular (P = .04) and liver-related (P = .04) causes. Seven patients (5.4%) developed end-stage liver disease, including 3 patients with hepatocellular carcinoma. The absence of periportal fibrosis at baseline had a negative predictive value of 100% in predicting liver-related complications. At follow-up, 69 of 88 patients had diabetes or impaired glucose tolerance. Progression of liver fibrosis occurred in 41%. These subjects more often had a weight gain exceeding 5 kg (P = .02), they were more insulin resistant (P = .04), and they exhibited more pronounced hepatic fatty infiltration (P = .03) at follow-up. In conclusion, NAFLD with elevated liver enzymes is associated with a clinically significant risk of developing end-stage liver disease. Survival is lower in patients with NASH. Most NAFLD patients will develop diabetes or impaired glucose tolerance in the long term. Progression of liver fibrosis is associated with more pronounced insulin resistance and significant weight gain.
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- 2006
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13. Semiquantitative evaluation overestimates the degree of steatosis in liver biopsies: a comparison to stereological point counting.
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Franzén LE, Ekstedt M, Kechagias S, and Bodin L
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- Biopsy methods, Humans, Reproducibility of Results, Severity of Illness Index, Fatty Liver pathology, Liver pathology
- Abstract
The degree of steatosis in liver biopsies is usually assessed by a morphological semiquantitative approach in which the histopathologist uses a four-graded scale: 0-3 or none, slight, moderate and severe. Scores 1-3 are considered to correspond to fat deposition in <33, 33-66 and >66% of the hepatocytes. There is a considerable inter- and intra-individual variation in such scoring methods and a more standardized and quantitative approach is preferable. In the present study, we compare the semiquantitative technique with the stereological point counting method in the assessment of hepatic steatosis. A total of 75 archived liver needle biopsies were used. They were selected according to the original routine diagnosis of slight, moderate or severe steatosis. In all, 10 randomly selected images from each biopsy were digitized into a computer, a point grid lattice was superimposed and the number of hits on fat globules was counted. A pathologist scored the specimens in a four-graded scale as described above. The mean liver biopsy area (volume) with fat in hepatocytes was 2.2% for grade 1, 9.2% for grade 2 and 23.1% for grade 3. The kappa value for the semiquantitative estimates was 0.71 for the unweigthed kappa and 0.87 for weighted kappa. The intraclass correlation coefficient (ICC) was 0.99 for images counted twice and 0.95 when two sets of images were captured from the same biopsy. These ICCs indicate excellent agreement and above that of the semiquantitative estimates. In conclusion, the area/volume of fat content of the hepatocytes is greatly overemphasized in semiquantitative estimation. Furthermore, the point counting technique has a better reproducibility than visual evaluation and should be preferred in estimates of liver steatosis in scientific studies and in clinical contexts when the amount of steatosis is important for treatment and prognosis, such as liver transplantation.
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- 2005
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14. Helicobacter pylori-specific antibodies impair the development of gastritis, facilitate bacterial colonization, and counteract resistance against infection.
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Akhiani AA, Schön K, Franzén LE, Pappo J, and Lycke N
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- Administration, Oral, Animals, Antibodies, Bacterial biosynthesis, Cell Fractionation, Cholera Toxin administration & dosage, Cholera Toxin immunology, Colony Count, Microbial, Cytokines biosynthesis, Gastritis genetics, Gastritis pathology, Helicobacter Infections genetics, Helicobacter Infections microbiology, Helicobacter Infections pathology, Immunity, Innate genetics, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Stomach immunology, Stomach microbiology, Stomach pathology, Th1 Cells immunology, Th1 Cells metabolism, Th2 Cells immunology, Th2 Cells metabolism, Antibodies, Bacterial physiology, Antibody Specificity, Gastritis immunology, Gastritis prevention & control, Helicobacter Infections immunology, Helicobacter pylori growth & development, Helicobacter pylori immunology
- Abstract
In recent years, Abs have been considered a correlate rather than an effector of resistance against Helicobacter pylori infection. However, it is still poorly understood to what extent Ab production correlates with gastric immunopathology. Here we report that Abs not only are dispensable for protection, but they are detrimental to elimination of the bacteria and appear to impair gastric inflammatory responses. We found that the initial colonization with H. pylori bacteria was normal in the B cell-deficient (microMT) mice, whereas at later times (>8 wk) most of the bacteria were cleared, concomitant with the development of severe gastritis. In contrast, wild-type (WT) mice exhibited extensive bacterial colonization and only mild gastric inflammation, even at 16 wk after inoculation. Oral immunizations with H. pylori lysate and cholera toxin adjuvant stimulated comparable levels of protection in microMT and WT mice. The level of protection in both strains correlated well with the severity of the postimmunization gastritis. Thus, T cells were responsible for the gastritis, whereas Abs, including potentially host cell cross-reactive Abs, were not involved in causing the gastritis. The T cells in micro MT and WT mice produced high and comparable levels of IFN-gamma to recall Ag at 2 and after 8 wk, whereas IL-4 was detected after 8 wk only, indicating that Th1 activity dominated the early phase of protection, whereas later a mixed Th1 and Th2 activity was seen.
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- 2004
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15. Protection against Helicobacter pylori infection following immunization is IL-12-dependent and mediated by Th1 cells.
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Akhiani AA, Pappo J, Kabok Z, Schön K, Gao W, Franzén LE, and Lycke N
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- Animals, Antibodies, Bacterial biosynthesis, Antibodies, Bacterial blood, Epitopes, T-Lymphocyte immunology, Gastritis genetics, Gastritis immunology, Helicobacter Infections genetics, Immunization, Secondary, Immunoglobulin A biosynthesis, Immunoglobulin A blood, Immunoglobulin G biosynthesis, Immunoglobulin G blood, Interferon-gamma biosynthesis, Interferon-gamma deficiency, Interferon-gamma genetics, Interleukin-12 deficiency, Interleukin-12 genetics, Lymphopenia genetics, Lymphopenia immunology, Mice, Mice, Inbred C57BL, Mice, Knockout, Th1 Cells metabolism, Th1 Cells pathology, Th2 Cells immunology, Helicobacter Infections immunology, Helicobacter Infections prevention & control, Helicobacter pylori immunology, Interleukin-12 physiology, Th1 Cells immunology, Vaccination
- Abstract
The regulatory roles of Th1 and Th2 cells in immune protection against Helicobacter infection are not clearly understood. In this study, we report that a primary H. pylori infection can be established in the absence of IL-12 or IFN-gamma. However, IFN-gamma, but not IL-12, was involved in the development of gastritis because IFN-gamma(-/-) (GKO) mice exhibited significantly less inflammation as compared with IL-12(-/-) or wild-type (WT) mice. Both IL-12(-/-) and GKO mice failed to develop protection following oral immunization with H. pylori lysate and cholera toxin adjuvant. By contrast, Th2-deficient, IL-4(-/-), and WT mice were equally well protected. Mucosal immunization in the presence of coadministered rIL-12 in WT mice increased Ag-specific IFN-gamma-producing T cells by 5-fold and gave an additional 4-fold reduction in colonizing bacteria, confirming a key role of Th1 cells in protection. Importantly, only protected IL-4(-/-) and WT mice demonstrated substantial influx of CD4(+) T cells in the gastric mucosa. The extent of inflammation in challenged IL-12(-/-) and GKO mice was much reduced compared with that in WT mice, indicating that IFN-gamma/Th1 cells also play a major role in postimmunization gastritis. Of note, postimmunization gastritis in IL-4(-/-) mice was significantly milder than WT mice, despite a similar level of protection, indicating that immune protection is not directly linked to the degree of gastric inflammation. Only protected mice had T cells that produced high levels of IFN-gamma to recall Ag, whereas both protected and unprotected mice produced high levels of IL-13. We conclude that IL-12 and Th1 responses are crucial for H. pylori-specific protective immunity.
- Published
- 2002
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16. Gastric epithelial proliferation and p53 and p21 expression in a general population sample: relations to age, sex, and mucosal changes associated with H. pylori infection.
- Author
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Petersson F, Borch K, and Franzén LE
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- Adult, Aged, Aged, 80 and over, Cell Division, Epithelium metabolism, Female, Gastritis metabolism, Humans, Immunohistochemistry, Ki-67 Antigen metabolism, Male, Middle Aged, Gastric Mucosa metabolism, Helicobacter Infections metabolism, Helicobacter pylori, Proto-Oncogene Proteins p21(ras) metabolism, Tumor Suppressor Protein p53 metabolism
- Abstract
Helicobacter pylori infection is the main cause of chronic gastritis. The infection has been linked to altered proliferative activity and changes in various cell cycle regulating proteins. To determine, in a general population sample, the proliferative activity and expression of p53 and p21 in males and females of different age groups with and without H. pylori-associated chronic gastritis, gastric biopsies from 273 subjects (188 with and 85 without H. pylori infection) randomly selected from a general population were examined immunohistochemically for Ki-67, p53, and p21. One thousand epithelial cells, including the surface, neck, and glandular areas, were counted in both the corpus and the antrum. Results are expressed as the percentage of positive cells. Subjects with H. pylori infection showed significantly increased proliferative activity and expression of p53 compared to uninfected individuals. Regarding the expression of p21, no difference was detected. Multiple linear regression analysis showed significant associations between chronic inflammation or inflammatory activity, on the one hand, and the degree of proliferation in both the corpus and the antrum, on the other hand. In the antrum, the degree of H. pylori colonization was related to the expression of p53. H. pylori seems to cause increased proliferation and increased expression of p53 (but not p21) in the gastric mucosa, neither of which is age or sex dependent. The proliferative activity is related mainly to events associated with inflammation, while the expression of p53 in the antrum is associated with the degree of H. pylori infection. The action of p53 appears to be independent of p21 activity.
- Published
- 2002
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17. Increased liver echogenicity at ultrasound examination reflects degree of steatosis but not of fibrosis in asymptomatic patients with mild/moderate abnormalities of liver transaminases.
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Mathiesen UL, Franzén LE, Aselius H, Resjö M, Jacobsson L, Foberg U, Frydén A, and Bodemar G
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- Adult, Aged, Biomarkers blood, Biopsy, Body Mass Index, Diagnosis, Differential, Fatty Liver complications, Female, Humans, Liver pathology, Liver Cirrhosis complications, Male, Middle Aged, Obesity complications, Obesity diagnosis, Obesity enzymology, Predictive Value of Tests, Sensitivity and Specificity, Severity of Illness Index, Statistics as Topic, Sweden, Fatty Liver diagnosis, Fatty Liver enzymology, Liver diagnostic imaging, Liver enzymology, Liver Cirrhosis diagnosis, Liver Cirrhosis enzymology, Transaminases metabolism, Ultrasonography, Interventional
- Abstract
Aims: To investigate whether hyperechogenicity of liver can reliably be interpreted as liver steatosis and if any concomitant or isolated fibrosis can be disclosed., Patients and Methods: A series of 165 patients with no signs or symptoms of liver disease referred because of slightly to moderately raised aminotransferases (alanine aminotransferase and/or aspartate aminotransferase 0.7-5.0 microkat/l) for more than 6 months were prospectively investigated with a comprehensive laboratory profile, ultrasound examination of liver and percutaneous liver biopsy Fibrosis was assessed quantitatively and according to Metavir. Steatosis was graded as none, mild, moderate or severe., Results: Of 98 (59.4%) patients with raised echogenicity, 85 (86.7%) had liver steatosis of at least moderate degree, 9 patients with same degree of steatosis had normal echogenicity and 13 patients with no or only mild steatosis had a hyperechogenic liver (sensitivity 0.90, specificity 0.82, positive predictive value 0.87, negative predictive value 0.87). About the same relations were found regardless of body mass index and degree of fibrosis. With increased echogenicity together with high attenuation (n = 591 and reduced portal vessel wall distinction (n = 79), positive predictive value increased to 0.93 and 0.94, respectively. Quantitatively assessed fibrosis (mean +/- SD) was 3.2 +/- 4.6% of biopsy area with normal and 2.3 +/- 1.8% with raised echogenicity (ns). Echogenicity was normal in 5 out of 9 patients with septal fibrosis and in 4 out of 6 patients with cirrhosis. Any structural, non-homogenous findings at ultrasound were not associated with architectural fibrotic changes and none had nodular contours of liver surface., Conclusions: Assessment of liver echogenicity is of value for detection or exclusion of moderate to pronounced fatty infiltration (correct classification 86.6%) but cannot be relied upon in diagnosing fibrosis, not even cirrhosis in asymptomatic patients with mild to moderately elevated liver transaminases.
- Published
- 2002
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18. Augmented increase in tight junction permeability by luminal stimuli in the non-inflamed ileum of Crohn's disease.
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Söderholm JD, Olaison G, Peterson KH, Franzén LE, Lindmark T, Wirén M, Tagesson C, and Sjödahl R
- Subjects
- Actins analysis, Adult, Aged, Aged, 80 and over, Colonoscopy, Crohn Disease pathology, Decanoic Acids pharmacology, Diffusion Chambers, Culture, Electrophysiology, Enterocytes ultrastructure, Female, Follow-Up Studies, Humans, Ileum ultrastructure, Intestinal Absorption physiology, Intestinal Mucosa physiopathology, Intestinal Mucosa ultrastructure, Male, Middle Aged, Mitochondria ultrastructure, Permeability drug effects, Tight Junctions ultrastructure, Crohn Disease physiopathology, Ileum physiopathology, Tight Junctions physiology
- Abstract
Background: Crohn's disease is associated with deranged intestinal permeability in vivo, suggesting dysfunction of tight junctions. The luminal contents are important for development of neoinflammation following resection. Regulation of tight junctions by luminal factors has not previously been studied in Crohn's disease., Aims: The aim of the study was to investigate the effects of a luminal stimulus, known to affect tight junctions, on the distal ileum in patients with Crohn's disease., Patients: Surgical specimens from the distal ileum of patients with Crohn's disease (n=12) were studied, and ileal specimens from colon cancer patients (n=13) served as controls., Methods: Mucosal permeability to 51Cr-EDTA and electrical resistance were studied in Ussing chambers during luminal exposure to sodium caprate (a constituent of milk fat, affecting tight junctions) or to buffer only. The mechanisms involved were studied by mucosal ATP levels, and by electron and confocal microscopy., Results: Baseline permeability was the same in non-inflamed ileum of Crohn's disease and controls. Sodium caprate induced a rapid increase in paracellular permeability--that is, increased permeation of 51Cr-EDTA and decreased electrical resistance--which was more pronounced in non-inflamed ileum of Crohn's disease, and electron microscopy showed dilatations within the tight junctions. Moreover, sodium caprate induced disassembly of perijunctional filamentous actin was more pronounced in Crohn's disease mucosa. Mucosal permeability changes were accompanied by mitochondrial swelling and a fall in epithelial ATP content, suggesting uncoupling of oxidative phosphorylation., Conclusions: The tight junctions in the non-inflamed distal ileum of Crohn's disease were more reactive to luminal stimuli, possibly mediated via disturbed cytoskeletal contractility. This could contribute to the development of mucosal neoinflammation in Crohn's disease.
- Published
- 2002
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19. Prevalence of subtypes of intestinal metaplasia in the general population and in patients with autoimmune chronic atrophic gastritis.
- Author
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Petersson F, Borch K, and Franzén LE
- Subjects
- Biopsy, Needle, Case-Control Studies, Chronic Disease, Comorbidity, Culture Techniques, Female, Gastric Mucosa microbiology, Gastritis, Atrophic microbiology, Helicobacter Infections pathology, Helicobacter pylori isolation & purification, Humans, Intestinal Neoplasms microbiology, Intestinal Neoplasms pathology, Male, Precancerous Conditions pathology, Prevalence, Probability, Reference Values, Sampling Studies, Severity of Illness Index, Statistics, Nonparametric, Gastric Mucosa pathology, Gastritis, Atrophic epidemiology, Gastritis, Atrophic pathology, Helicobacter Infections epidemiology, Intestinal Neoplasms epidemiology, Precancerous Conditions epidemiology
- Abstract
Background: Gastric intestinal metaplasia (IM) is seen mostly in association with chronic gastritis, induced either by Helicobacter pylori infection or autoimmune mechanisms. IM can be categorized into three subtypes, where type III is associated with gastric carcinoma of intestinal type., Methods: Gastric biopsies from 475 subjects randomly selected from the general population and from 27 patients with autoimmune gastritis associated with pernicious anaemia were used. The criteria of Filipe & Jass were applied using different histochemical techniques in combination with haematoxylin and eosin stained material., Results: Twenty-three percent (109/475) of the subjects from the general population and 88% (24/27) in the group with autoimmune gastritis had IM. Type III IM occurred in 4% in both populations. Type III IM was located in the antrum in 90% in the general population. In the group with autoimmune gastritis, only one patient had type III IM, which was located in the corpus., Conclusions: This study reveals for the first time the prevalence and distribution of subtypes of IM in a general population from the Western world. The comparatively high prevalence of type III IM in the general population (4%) indicates that its role as a precursor of gastric carcinoma may have been overemphasized. A similar prevalence of type III IM in patients with autoimmune gastritis may be considered low and suggests that mechanisms for gastric carcinogenesis other than the atrophy-metaplasia-dysplasia sequence could also operate in this condition.
- Published
- 2002
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20. Carrageenan-induced subacromial bursitis caused changes in the rat's rotator cuff.
- Author
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Tillander B, Franzén LE, Nilsson E, and Norlin R
- Subjects
- Acromion pathology, Animals, Bursitis pathology, Carrageenan administration & dosage, Female, Fibrinogen analysis, Fibronectins analysis, Fluorescein-5-isothiocyanate, Fluorescent Antibody Technique, Injections, Intra-Articular, Rats, Rats, Sprague-Dawley, Rotator Cuff chemistry, Rotator Cuff pathology, Single-Blind Method, Acromion drug effects, Bursitis chemically induced, Carrageenan pharmacology, Rotator Cuff drug effects
- Abstract
This study was designed to investigate the histologic expression of the rat's supra- and infraspinatus tendons in carrageenan-induced subacromial bursitis. Thirty-two rats received subacromial injections with carrageenan (n = 28) or saline (n = 4). The tendons were analysed microscopically after staining with hematoxyline eosin, Van Giesons hematoxyline and immunofluorescent staining of fibronectin and fibrinogen. In the controls (saline x 10) and group A (carrageenan x 5) there were no changes in the tendons. In group B (carrageenan x 10) 3/8 rats showed macrophages between the collagen fibres and an increased staining of fibronectin. In group C (double dosis carrageenan) all rats had signs of fibrocartilaginous metaplasia in the supraspinatus tendon. In eight of these specimens even bony metaplasia was seen. The infraspinatus tendon showed fibrosis but no fibrocartilaginous metaplasia. The results showed that iatrogenic bursitis after carrageenan subacromial injections was associated with marked changes of the supraspinatus tendon.
- Published
- 2001
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21. Prevalence of gastroduodenitis and Helicobacter pylori infection in a general population sample: relations to symptomatology and life-style.
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Borch K, Jönsson KA, Petersson F, Redéen S, Mårdh S, and Franzén LE
- Subjects
- Adult, Aged, Anti-Inflammatory Agents, Non-Steroidal therapeutic use, Duodenitis complications, Esophageal Diseases complications, Female, Gastritis complications, Gastrointestinal Diseases complications, Helicobacter Infections complications, Humans, Life Style, Male, Middle Aged, Prevalence, Sweden, Duodenitis epidemiology, Gastritis epidemiology, Helicobacter Infections epidemiology, Helicobacter pylori
- Abstract
Some benign and malignant diseases develop on the background of chronic gastritis or duodenitis. The present study was performed in order to determine the magnitude of these background changes with relations to symptomatology and life style in the general population. Examinations were performed in 501 volunteers (age 35-85 years). Fifty percent had gastritis; this was associated with H. pylori in 87%. H. pylori-negative gastritis was associated with regular use of NSAIDs [odds ratio 3.8 (1.6-9.9)]. Duodenitis, observed in 32%, was associated with H. pylori infection [odds ratio 2.3 (1.3-4.6)], previous cholecystectomy [odds ratio 3.6 (1.1-16.1)], and regular use of NSAIDs [odds ratio 3.0 (1.4-7.1)]. Neither gastritis nor duodenitis was associated with smoking or alcohol consumption. The rate of digestive symptoms did not differ between subjects with and without uncomplicated gastritis or duodenitis. In conclusion, half of this adult population had gastritis strongly associated with H. pylori infection. Gastritis without H. pylori infection was frequently associated with regular NSAID intake. One third had duodenitis, which was associated with H. pylori infection as well as with regular use of NSAIDs and previous cholecystectomy. Digestive symptoms were not overrepresented in uncomplicated gastritis or duodenitis.
- Published
- 2000
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22. Epithelial permeability to proteins in the noninflamed ileum of Crohn's disease?
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Söderholm JD, Peterson KH, Olaison G, Franzén LE, Weström B, Magnusson KE, and Sjödahl R
- Subjects
- Adult, Aged, Colonic Neoplasms metabolism, Crohn Disease physiopathology, Dextrans pharmacokinetics, Edetic Acid pharmacokinetics, Electrophysiology, Female, Humans, Macromolecular Substances, Male, Microscopy, Confocal, Middle Aged, Ovalbumin pharmacokinetics, Permeability, Crohn Disease metabolism, Ileum metabolism, Intestinal Mucosa metabolism
- Abstract
Background & Aims: Crohn's disease (CD) is associated with a disturbed intestinal barrier. Permeability studies have focused on inert molecules, but little is known about transepithelial transport of macromolecules with antigenic potential in humans. The aim of this study was to quantify permeation and to characterize passage routes for macromolecules in ileal mucosa in CD., Methods: Noninflamed and inflamed ileal mucosa specimens from patients with CD (n = 12) and ileal specimens from patients with colon cancer (n = 7) were studied regarding transmucosal permeation of ovalbumin, dextran (mol wt, 40,000), and 51Cr-EDTA for 90 minutes in vitro in Ussing chambers. Transepithelial passage routes for fluorescent ovalbumin and dextran 40,000 were investigated by confocal microscopy., Results: Noninflamed ileum from CD patients showed increased permeation of ovalbumin compared with ileum from colon cancer patients (P < 0.05). Dextran permeation was equal in the three groups, whereas 51Cr-EDTA permeability was increased in inflamed ileum. Ovalbumin passed both transcellularly and paracellularly, but dextran followed a strictly paracellular route. Both markers were subsequently endocytosed by cells of the lamina propria., Conclusions: Noninflamed ileal mucosa from patients with CD shows increased epithelial permeability to ovalbumin, probably by augmented transcytosis. This increase in antigen load to the lamina propria could be an initiating pathogenic event in CD.
- Published
- 1999
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23. Effect of steroid injections on the rotator cuff: an experimental study in rats.
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Tillander B, Franzén LE, Karlsson MH, and Norlin R
- Subjects
- Animals, Anti-Inflammatory Agents administration & dosage, Female, Joint Diseases complications, Pain drug therapy, Rats, Rats, Sprague-Dawley, Rotator Cuff drug effects, Shoulder Joint pathology, Tendons drug effects, Tendons pathology, Triamcinolone administration & dosage, Anti-Inflammatory Agents adverse effects, Rotator Cuff pathology, Triamcinolone adverse effects
- Abstract
The aim of this study was to evaluate the effects of repeated steroid injections into the subacromial space. Thirty rats were injected either 3 or 5 times with triamcinolone in a dosage equivalent to that given to human beings or 3 or 5 times with saline into the subacromial space. One rat received no injection. The supraspinatus and infraspinatus tendons were evaluated macroscopically and microscopically. Two different staining methods were used on each sample including hematoxylin eosin and Miller's elastin/van Gieson's solution. After 5 steroid injections, we found focal inflammation, necrosis, and fragmentation of collagen bundles in the tendon in 4 of 7 rats. The tendons of the controls showed a normal structure (P < .05). There were no pathologic changes among the rats that were injected with triamcinolone 3 times. These results show that repeated subacromial injections of triamcinolone may cause damage to the rotator cuff of the rat. This finding may indicate cautious use of subacromial steroid injections in human beings.
- Published
- 1999
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24. The clinical significance of slightly to moderately increased liver transaminase values in asymptomatic patients.
- Author
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Mathiesen UL, Franzén LE, Frydén A, Foberg U, and Bodemar G
- Subjects
- Autoantibodies blood, Fatty Liver diagnosis, Fatty Liver enzymology, Female, Hepatitis C, Chronic diagnosis, Hepatitis C, Chronic enzymology, Hepatitis, Alcoholic diagnosis, Hepatitis, Alcoholic enzymology, Hepatitis, Autoimmune blood, Hepatitis, Autoimmune diagnosis, Hepatitis, Autoimmune enzymology, Hepatitis, Chronic diagnosis, Hepatitis, Chronic enzymology, Humans, Liver Cirrhosis diagnosis, Liver Cirrhosis enzymology, Liver Cirrhosis, Biliary diagnosis, Liver Cirrhosis, Biliary enzymology, Male, alpha 1-Antitrypsin Deficiency diagnosis, alpha 1-Antitrypsin Deficiency enzymology, Alanine Transaminase metabolism, Aspartate Aminotransferases metabolism, Liver Diseases diagnosis, Liver Diseases enzymology
- Abstract
Background: Our aim was to study liver disorders in asymptomatic patients with slightly to moderately increased liver transaminase values in a population living in an area with a low prevalence of viral and hereditary liver diseases., Methods: One hundred and fifty consecutive patients with slightly to moderately increased liver transaminases for at least 6 months without symptoms or signs of liver disease were included. Median (range) was 0.75 microkat/l (0.24-2.9) for aspartate aminotransferase (ASAT) and 1.18 microkat/l (0.28-4.5) for alanine aminotransferase (ALAT). A percutaneous liver biopsy was performed, and blood was sampled for a detailed biochemical and serologic profile., Results: Chronic viral hepatitis C was found in 15.3% of the patients, autoimmune hepatitis in 1.3%, primary biliary cirrhosis in 1.3%, and heterozygotic alpha-1-antitrypsin deficiency in 0.7%. Presumed alcoholic liver disease was diagnosed in 8%, and non-alcoholic steatohepatitis in 2%. Chronic hepatitis with no obvious etiology was diagnosed in 24%, of whom 39% had interface hepatitis (piecemeal activity). Seventy-one per cent of these 39% had measurable levels of autoantibodies, but IgG levels within normal limits prevented the 'clinical' diagnosis of autoimmune hepatitis. Liver steatosis was the diagnosis in 40%. Most were overweight and had increased serum triglyceride levels. However, in 13.3% the fatty infiltration was considered 'essential', as both body mass index (BMI) and triglyceride levels were normal. Other diagnoses were liver fibrosis with no obvious inflammatory activity (3.3%), cirrhosis of unknown etiology (0.7%), and for the remaining (3.3%) patients histopathologic findings were considered 'normal'. Cirrhosis was found in five biopsy specimens: hepatitis C (n = 2), autoimmune hepatitis (n = 1), primary biliary cirrhosis (n = 1), and cryptogenic cirrhosis (n = 1). No concomitant disease was of importance for the diagnosis and/or histopathologic findings. No obvious drug-related increased liver test results were found with any single drug. However, patients with chronic hepatitis of unknown etiology, especially with interface hepatitis, significantly more often than the rest of the population were receiving drug treatment., Conclusion: Most transaminitis patients had steatosis, and some had defined diseases including chronic hepatitis C. Chronic hepatitis of unknown etiology was found in a substantial proportion (24%) of a population living in an area with a low burden of hepatic viruses and genetic disorders.
- Published
- 1999
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25. Fibroblast movements during contraction of collagen lattices--a quantitative study using a new three-dimensional time-lapse technique with phase-contrast laser scanning microscopy.
- Author
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Tarpila E, Ghassemifar RM, and Franzén LE
- Subjects
- Connective Tissue physiology, Humans, Microscopy, Confocal, Microscopy, Phase-Contrast, Cell Movement, Collagen, Fibroblasts physiology
- Abstract
In this study we assessed the behavior of fibroblasts during contraction of collagen lattices. We applied a new technique for three-dimensional time-lapse studies of movements of living cells using phase-contrast laser scanning microscopy. Five anchored and five floating collagen lattices were studied regarding the activity of cells during a 7-h period of active contraction. Three-dimensional reconstructions of the fibroblasts and their extensions were made from datasets of 16-26 "optical sections" 5 microm apart recorded hourly during the period of measurements. The distance between fibroblast nuclei in the floating lattices decreased by a mean of 6.8 microm, but remained constant in the anchored group. Only minor variations were found in the angle between a line connecting any two nuclei and the tangent of the lattice margin. The lengths of the cellular extensions continuously changed by shortening and extending, and an increasing number of intercellular contacts were established with time. The angle between the extensions and the periphery of the lattice varied continually, and no distinct pattern of arrangement of the extensions was seen. In conclusion, we have shown in living cells in vitro that fibroblasts do not appear to move around within lattices during contraction but rather send out and withdraw cellular extensions continuously. This speaks against cellular locomotion or movement as a main feature of contraction. Time-lapse scanning laser microscopy has also been shown to be a suitable method to study cellular behavior quantitatively in three dimensions during lattice contraction.
- Published
- 1998
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26. Alpha-smooth muscle actin expression in rat and mouse mesenteric wounds after transforming growth factor-beta1 treatment.
- Author
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Ghassemifar R, Schultz GS, Tarnuzzer RW, Salerud G, and Franzén LE
- Abstract
Rat mesenteric perforations heal by contraction within 5 to 7 days, whereas mouse mesenteric perforations seldom close within 3 weeks unless stimulated by transforming growth factor-beta1. In this article, we quantified the expression of alpha-smooth muscle actin by quantitative-reverse transcription-polymerase chain reaction and the orientation of actin filaments at the wound margin by Fourier transformation image analysis after treatment with transforming growth factor-beta1. The expression of transforming growth factor-beta1 and its type II receptor was also assessed. Actin filaments were shown to increase with time at the wound margin in both species and the expression of alpha-smooth muscle actin mRNA increased simultaneously. Transforming growth factor-beta1 enhanced the alpha-smooth muscle actin expression four to five times in rats and three to four times in mice on day 5, but the number of copies expressed per cell was 15-fold higher in rats than in mice. Transforming growth factor-beta1 was down-regulated after wounding in free peritoneal cells of rats, but maintained until day 5 in transforming growth factor-beta1-treated mice. The main finding of this study was that untreated, normal rats expressed substantially more alpha-smooth muscle actin than mice. After treatment with transforming growth factor-beta1, this expression increased similarly in both species. It can be hypothesized that normal closure of mesenteric perforations requires a minimum level of actin expression. This level is not reached in normal mice, but is exceeded after stimulation. Perforations in the rat always close, because the alpha-smooth muscle actin expression is always above this level.
- Published
- 1997
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27. Stimulation of protracted connective tissue repair in normal mice by transforming growth factor beta 1.
- Author
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Franzén LE, Ghassemifar MR, Lönnberg B, Schultz GS, and Tarpila E
- Subjects
- Animals, Male, Mice, Mice, Inbred Strains, Mitotic Index, Connective Tissue physiology, Mesentery pathology, Transforming Growth Factor beta physiology, Wound Healing physiology
- Abstract
The repair and contraction during connective tissue repair of mesenteric perforations is prolonged in mice compared with rats. In the present study the stimulating effect of transforming growth factor beta 1 (TGF-beta 1) on different aspects of such repair of the mouse mesentery was assessed. The number of closed mesenteric perforations were counted on different days after operation and the free peritoneal cells were counted, the mitotic index was assessed, and actin distribution of fibroblasts around the perforation was studied with laser scanning confocal microscopy. TGF-beta 1 significantly increased the speed of closure and seemed to induce more actin in fibroblasts at the wound margin. It did not significantly influence the mitotic index, but fewer free peritoneal cells were obtained in mice treated with TGF-beta 1. We conclude that TGF-beta 1 is a potent stimulator of connective tissue repair and contraction in mice. The different methods of closure in rats and mice implicate different molecular responses in wounds and further studies on the stimulating effect of TGF-beta 1 may indicate basic fibroblastic cellular mechanisms that are active during contraction in connective tissue repair.
- Published
- 1996
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28. Actin fiber orientation in connective tissue contraction: a quantitative study with the perforated rat mesentery model.
- Author
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Franzén LE, Reza Ghassemifar M, Salerud G, and Tarpila E
- Abstract
Numerous fibroblasts with long cytoplasmic protrusions containing F-actin appear during closure by contraction of rat mesenteric perforations. These protrusions are predominantly arranged parallel to the wound margin. In the present study, the spatial and temporal organization of such protrusions was quantitated during normal and retarded healing in zinc-deficient animals. An orientation index, which gives the global orientation of the F-actin fibers, was calculated after Fourier transformation of images generated in a laser confocal microscope. Actin-rich fibroblasts began to accumulate at the wound margin on the first postoperative day, and the amount of actin gradually increased with time. The orientation index of the F-actin in unperforated mesenteric membranes was low, whereas the orientation index around perforations increased significantly (p < 0.001) with time and reached a maximum level on postoperative days 5 to 7. The orientation index was significantly lower (p < 0.02) in membranes with retarded healing in zinc-deficient animals than in controls. The findings show that image analysis can give valuable information about fibroblast organization during tissue repair and indicate that the spatial organization of the fibroblasts is an important factor in connective tissue contraction.
- Published
- 1996
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29. The perforated mesentery of the rat: a novel model for the study of genuine connective tissue contraction.
- Author
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Franzén LE
- Subjects
- Actins metabolism, Animals, Connective Tissue pathology, Connective Tissue ultrastructure, Disease Models, Animal, Fibroblasts metabolism, Fibroblasts ultrastructure, Male, Membranes injuries, Membranes pathology, Mesentery injuries, Mesentery pathology, Mice, Microscopy, Confocal, Microscopy, Electron, Rats, Rats, Sprague-Dawley, Connective Tissue injuries, Connective Tissue physiopathology, Wound Healing
- Abstract
The rat and mouse mesenteries consist of an array of thin, mesenchymally derived, connective tissue membranes. Perforations of rat membranes heal by closure within a week and the perforated rat mesentery has earlier been shown to be a very suitable model of true connective tissue repair. In the present study, the closure of perforations in the rat was studied by light and transmission electron microscopy as well as confocal microscopy after actin staining with phallacidin in order to better understand the cellular mechanisms of healing in this model. The healing of different sized mesenteric perforations was also quantitatively assessed and compared in rats and mice. Closure occurred rapidly between Days 5 and 7 in rats, the velocity of healing being dependent on the size of the wounds. During closure, fibroblasts close to the wound margin ultrastructurally showed long slender cytoplasmic processes that contained actin filaments as shown by fluorescence confocal microscopy. In mice, larger perforations of mesenteries decreased in size during the 3-week observation period, but very seldom closed completely. In conclusion, the data gathered now and earlier indicate that a contraction phenomenon is of major importance in the closure of rat mesenteric perforations. Until now, good models for genuine connective tissue contraction have been lacking and it is suggested that the perforated rat mesentery may be used as such a model system in the future. The finding that mouse mesenteric perforations normally do not heal will make comparative studies intriguing, but it also indicates basic differences between rats and mice with respect to connective tissue repair mechanisms.
- Published
- 1996
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30. Mechanisms of TGF-beta action in connective tissue repair of rat mesenteric wounds.
- Author
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Franzén LE, Ghassemifar N, Nordman J, Schultz G, and Skogman R
- Abstract
We have recently reported that transforming growth factor-beta stimulates genuine connective tissue repair in the perforated rat mesentery and that this stimulation is not caused by increased macrophage chemotaxis. To further characterize the effect of transforming growth factor-beta(1) on the enhanced rate of wound closure, we performed a series of morphometric analyses with determination of mitotic index, fibroblast labeling index, cellular density, neovascularization, and scar tissue formation. Actin expression close to the wound margin was also evaluated morphologically. Fibroblast cell proliferation was not stimulated by transforming growth factor-beta(1) in either wounded or unwounded tissue. Transforming growth factor-beta(1) did, however, significantly increase the formation of healing tissue postoperative days 5 to 10 (p < 0.05) and angiogenesis was significantly stimulated by transforming growth factor-beta(1) postoperative days 7 and 10 (p < 0.005). The mean cellular density was significantly increased in unperforated, transforming growth factor-beta(1)-treated membranes from days 3 to 10, and increased expression of actin with time was observed close to the wound margin. Transforming growth factor-beta(1) was thus shown to be a potent stimulator of angiogenesis and healing tissue formation in connective tissue repair, but this stimulation mainly occurred after closure of perforations. The increased cellular density in the absence of stimulated proliferation and increased actin expression in wound cells indicate that contraction may be an important mechanism of connective tissue repair in the perforated rat mesentery.
- Published
- 1995
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31. Impaired function of postoperative macrophages from zinc-deficient rats decreases collagen contraction. Brief report.
- Author
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Ghassemifar MR, Olsson MG, Agren MS, and Franzén LE
- Subjects
- Acetylglucosaminidase metabolism, Animals, Cell Degranulation, Male, Rats, Rats, Sprague-Dawley, Surgical Procedures, Operative, beta-Galactosidase metabolism, Collagen physiology, Connective Tissue physiology, Macrophages physiology, Mesentery physiology, Zinc deficiency
- Abstract
Zinc deficiency impairs connective tissue contraction in the perforated rat mesentery model. Since the rat mesentery is almost avascular, free peritoneal macrophages are important for mesenteric repair. Impairment of contraction may thus be caused either by a direct effect of zinc deficiency on tissue cells or by hampered macrophage function. To further elucidate the role of macrophages in tissue contraction, we studied their effect on lattice contraction. A number of typical functions of macrophages in zinc deficiency were also investigated. Lattice contraction was significantly impaired by conditioned medium from zinc-deficient macrophages. Zinc deficiency did not influence peripheral blood leukocyte number, but postoperatively the number of peritoneal macrophages increased on days 7 and 10. A significant release of lysosomal enzymes from macrophages was recorded during phagocytosis, whilst no difference was observed between controls and zinc-deficient macrophages. Superoxide anion generation during phagocytosis was not significantly increased in zinc deficiency. Conditioned medium from zinc-deficient macrophages was shown to impair lattice contraction in vitro and the results are compatible with impaired macrophage function as a cause of decreased connective tissue contraction in vivo.
- Published
- 1995
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32. Impaired connective tissue repair in streptozotocin-induced diabetes shows ultrastructural signs of impaired contraction.
- Author
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Franzén LE and Roberg K
- Subjects
- Animals, Male, Mesentery injuries, Mesentery pathology, Mesentery physiopathology, Microscopy, Electron, Rats, Rats, Sprague-Dawley, Wounds, Penetrating pathology, Wounds, Penetrating physiopathology, Connective Tissue physiopathology, Diabetes Mellitus, Experimental pathology, Diabetes Mellitus, Experimental physiopathology, Wound Healing
- Abstract
Streptozotocin-induced diabetes mellitus is known to impair connective tissue repair in the perforated rat mesentery. The aim of the present investigation was to study quantitatively by morphometrical techniques the influence of diabetes on some aspects of the cellular ultrastructure related to connective tissue contraction in such healing. The cellular volume density increased significantly with time, presumably as a consequence of disappearance of interstitial edema. No difference was found in the amount of healing tissue formed between controls and diabetics. The surface volume density of the plasma membrane was significantly higher in control animals on Days 1-10, indicating an increased number of cellular protrusions and spikes which relate to the motility of the cells. The volume density of contractile filaments did not differ between controls and diabetics. The results suggest a reduced surface density of plasma membrane in diabetic cells, a finding which is compatible with reduced wound contraction in diabetes.
- Published
- 1995
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33. Macrophage-conditioned medium without serum enhances collagen gel contraction.
- Author
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Ghassemifar MR, Ghassemifar N, and Franzén LE
- Subjects
- Gels, Humans, Kinetics, Macrophages metabolism, Blood, Collagen physiology, Culture Media, Conditioned
- Published
- 1995
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34. Transforming growth factor-beta enhances connective tissue repair in perforated rat mesentery but not peritoneal macrophage chemotaxis.
- Author
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Franzén LE and Schultz GS
- Abstract
The perforated rat mesentery model was used to study the effect of transforming growth factor-beta (TGF-beta) on connective tissue repair and influx of macrophages into the peritoneal cavity during such repair. Sprague-Dawley rats were laparotomized, and mesenteric wounds were made with a scalpel. A daily intraperitoneal injection of 0.5 microg TGF-beta was given for either 2 or 4 days. After 1 to 10 days, the animals received an intravenous injection of tritium-labeled thymidine before decapitation. Macrophages were collected by peritoneal washing, and the number of closed perforations was counted. Peritoneal cells were quantitated and a labeling index was determined by autoradiography. TGF-beta given for either 2 (p < 0.001) or 4 (p < 0.004) days accelerated closure of perforations on days 3 to 7 after injury. Laparotomy as such significantly increased leukocyte influx (p < 0.004), as well as macrophage-labeling index (p < 0.02). However, TGF-beta did not significantly influence either leukocyte influx or macrophage-labeling index. We concluded that TGF-beta significantly enhances connective tissue repair in this perforated rat mesentery model and that TGF-beta-induced stimulation of repair is not caused by an increased influx of macrophages into the peritoneal cavity.
- Published
- 1993
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35. Connective tissue repair in zinc deficiency. An ultrastructural morphometric study in perforated mesentery in rats.
- Author
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Franzén LE and Ghassemifar MR
- Subjects
- Animals, Cell Membrane ultrastructure, Connective Tissue injuries, Connective Tissue ultrastructure, Male, Mesentery injuries, Mesentery physiopathology, Mesentery ultrastructure, Microscopy, Electron, Random Allocation, Rats, Rats, Sprague-Dawley, Connective Tissue physiopathology, Endoplasmic Reticulum ultrastructure, Wound Healing physiology, Zinc deficiency
- Abstract
Objective: To quantify measures of healing in zinc-deficient and healthy rats., Design: Randomized study., Material: 30 male Sprague-Dawley rats., Interventions: Zinc deficiency was induced in half the rats. All rats underwent laparotomy and standard perforations were made in the small intestinal mesentery with a scalpel. At 1, 3, 5, 7 and 10 days after operation 6 rats were killed by overdose of anaesthetic agents and the specimens of the mesentery were fixed., Main Outcome Measures: Measurement of cellular volume density, surface density of the rough endoplasmic reticulum, and surface density of the plasma membrane., Results: Perforations started to close on day 4, and most were closed by day 10. Cellular volume density reached its peak between days 3 and 5, as did surface density of rough endoplasmic reticulum. There were no significant differences between the two groups for either measurement. The surface density of the rough endoplasmic reticulum, however, was significantly higher in controls than in zinc deficient animals on days 3-10 (p less than 0.001). The surface density of the plasma membrane was significantly higher in zinc-deficient animals on days 1-3 (p less than 0.04), and in control animals on days 5-10 (p less than 0.01)., Conclusions: Protein synthesis and formation of scar tissue were slightly lower in the zinc-deficient animals, and the higher plasma membrane surface density implies that contraction may be an important part of healing in the small intestinal mesentery in rats.
- Published
- 1992
36. Structural studies on the carbohydrate portion of human antithrombin III.
- Author
-
Franzén LE, Svensson S, and Larm O
- Subjects
- Carbohydrate Conformation, Carbohydrate Sequence, Humans, Trifluoroacetic Acid, Antithrombin III
- Abstract
Human antithrombin III has been shown to contain four identical N-glycosidically linked carbohydrate chain per molecule. These carbohydrate chains have been investigated by sugar and methylation analysis before and after removal of N-acetylneuraminic acid residues. The chains have been further investigated by Smith degradation, trifluoroacetolytic degradation, and degradation after chromium trioxide oxidation. As a result of these studies, the following structures is proposed for the carbohydrate chains in human antithrombin III: (formula: see text). NeuNAc, N-acetylneuraminic acid; Galp, galactopyranose; GlcNAcp, 2-acetamido-2-deoxyglucopyranose; Manp, mannopyranose are the abbreviations used in the structure.
- Published
- 1980
37. Structural analysis of complex carbohydrates using high-performance liquid chromatography, gas chromatography, and mass spectrometry.
- Author
-
McNeil M, Darvill AG, Aman P, Franzén LE, and Albersheim P
- Subjects
- Alkylation, Chromatography, Gas methods, Chromatography, High Pressure Liquid methods, Magnetic Resonance Spectroscopy, Mass Spectrometry methods, Molecular Conformation, Oligosaccharides analysis, Polysaccharides analysis, Rhizobium analysis, Sugar Alcohols analysis, Carbohydrate Sequence, Carbohydrates analysis
- Published
- 1982
- Full Text
- View/download PDF
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