Yngve Raab

Uppsala University Hospital, Uppsala, Uppsala, Sweden

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Publications (10)30.61 Total impact

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    Article: Steroids reduce local inflammatory mediator secretion and mucosal permeability in collagenous colitis patients.
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    ABSTRACT: To study the effect of oral steroids upon clinical response and rectal mucosa secretion of eosinophil cationic protein (ECP), myeloperoxidase (MPO), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF) and albumin in patients with collagenous colitis (CC). A segmental perfusion technique was used to collect perfusates from rectum of CC patients once before and twice (one and four weeks) after the start of steroid treatment. Clinical data was monitored and ECP, MPO, bFGF, VEGF and albumin concentrations were analyzed by immunochemical methods in perfusates and in serum. Steroids reduced the number of bowel movements by more than five times within one week and all patients reported improved subjective well-being at wk 1 and 4. At the same time, the median concentrations of ECP, bFGF, VEGF and albumin in rectal perfusates decreased significantly. MPO values were above the detection limit in only 3 patients before treatment and in none during treatment. VEGF, bFGF, ECP and albumin concentrations correlated with each other with the exception of ECP and albumin. A decrease of serum ECP and VEGF concentrations was also seen even if the overtime reduction was not significant. Oral steroid treatment in CC patients induced a simultaneous reduction of bowel movements and rectal release of ECP, bFGF, VEGF and albumin, suggesting that these polypeptides and increased mucosal permeability are important components of the pathophysiology in collagenous colitis.
    World Journal of Gastroenterology 12/2006; 12(43):7012-8. · 2.47 Impact Factor
  • Article: Abdominoperineal excision with partial anterior en bloc resection in multimodal management of low rectal cancer: a strategy to reduce local recurrence.
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    ABSTRACT: Total mesorectal excision is the gold standard in the performance of an abdominoperineal resection but little has changed in the way the perineal operation is performed. A frequent problem is anterior dissection. The aim of this study was to present the results of abdominoperineal resection using selected partial anterior en bloc resection to reduce recurrence. The data were population-based and prospectively registered. Two experienced surgeons performed the operations. In selected cases, depending on clinical and magnetic resonance imaging findings, parts of the vagina or prostate close to the tumor were resected. All specimens were examined according to Quirke. Sixty-three patients underwent abdominoperineal resection with total mesorectal excision; 56 received preoperative radiotherapy. The tumors involved the anterior bowel wall in 40 cases and in 23 (58 percent) of them, en bloc resections were performed. The distance from the tumor to the conventional resection margin (without en bloc resection) was 0 mm in ten cases. The median follow-up period was 37 months. So far, one (1.7 percent) local recurrence has been detected in 58 (92 percent) curative and indeterminate cases. The cancer-specific five-year survival in these cases was 87 percent (Kaplan-Meier). A multimodal management regimen in patients with low rectal cancer, including preoperative radiotherapy and abdominoperineal resection with a high frequency of partial en bloc resection of the vagina or prostate, resulted in excellent local control and survival. In some male patients, excenteration with urinary stoma can be avoided.
    Diseases of the Colon & Rectum 07/2006; 49(6):833-40. · 3.13 Impact Factor
  • Article: Vascular endothelial growth factor (VEGF)--a possible mediator of inflammation and mucosal permeability in patients with collagenous colitis.
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    ABSTRACT: Patients with collagenous colitis have watery diarrhea and histopathologically thickened collagen layer with discrete signs of mucosal inflammation. Vascular endothelial growth factor (VEGF) is a potent angiogenic, mitogenic, permeability, and fibrosis enhancing peptide and it was studied by segmental perfusion and immunohistochemistry in patients and controls. The concentrations of VEGF were significantly increased in perfusates from both the descending colon and the rectum in patients compared to controls but this difference was not found in serum. Immunohistochemical staining showed expression of VEGF within colon epithelial cells, inflammatory cells, and fibroblasts in the lamina propria. The intensity of staining in the surface epithelium was not different between patients and controls but in the lamina propria the intensity was significantly higher among controls. Patients with collagenous colitis have increased colorectal mucosal secretion of VEGF, which may lead to albumin leakage and promote fibrosis with deposition of collagen.
    Digestive Diseases and Sciences 02/2004; 49(1):109-15. · 2.12 Impact Factor
  • Article: Mucosal secretion and expression of basic fibroblast growth factor in patients with collagenous colitis.
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    ABSTRACT: Collagenous colitis (CC), a condition of unknown ethiology and pathophysiology, is characterized by watery diarrhea and increased amounts of collagen in the colonic mucosa. Basic fibroblast growth factor (bFGF) is a potent multifunctional growth factor that stimulates proliferation and differentiation of fibroblasts that was recently detected in high intraluminal concentrations in patients with ulcerative colitis. In this study we examined the secretion and expression of bFGF in the colorectal mucosa of patients with CC. Ten CC patients and 10 control patients underwent colonoscope-based segmental perfusion of the descending colon and rectum. The concentrations of bFGF in perfusate and serum were determined by immunochemical methods, and the expression of bFGF was analyzed immunohistochemically in biopsy samples from colonic mucosa. The median concentrations of bFGF in perfusates from the descending colon and rectum were increased 4-fold in CC patients compared with control patients. The median concentration of bFGF in serum was not significantly different in patients and controls. Immunohistochemical staining of bFGF was located in the colorectal epithelial cells and in exsudate on the luminal side of these cells. In the lamina propria, inflammatory cells and fibroblasts contained bFGF. There were no differences in the intensity of bFGF staining in surface epithelium or lamina propria between patients and controls. Local investigation of the colorectal mucosa seems to be crucial when studying the pathophysiology of CC. Increased colorectal mucosal secretion of bFGF in patients with CC may promote differentiation of fibroblasts and thereby lead to increased subepithelial collagen deposition.
    The American Journal of Gastroenterology 10/2003; 98(9):2011-7. · 7.28 Impact Factor
  • Article: [Self-expanding stent in obstructing colorectal cancer. A new technique to avoid abdominal surgery].
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    ABSTRACT: Emergency operations for obstructing colorectal cancer are associated with high morbidity and mortality rates and often result in a temporary or permanent colostomy. A colorectal stent can be used both for palliation and as a "bridge to surgery". Twenty-three patients with obstructive sigmoid or rectal cancer were selected for stenting. Self-expanding metal mesh stents were placed under endoscopic and flouroscopic guidance. Stent placement was technically successful in 19 patients and clinical success was seen in 18. There were only three minor complications, no major and no procedure related mortality. Four patients were later resected without a diverting stoma, two with rectal cancer had preoperative MRI and radiotherapy. In 15 patients the procedure was regarded as palliative. Stent migration was noted in four patients but symptomatic reobstruction did not occur, no patient needed later surgery. Colorectal stenting procedure is effective and safe and can be used in obstructing cancers both as a temporary relief before elective resection and as a definitive treatment in palliative cases.
    Lakartidningen 06/2003; 100(22):1982-6.
  • Article: Local release of human neutrophil lipocalin (HNL), IL-8, and TNF-alpha is decreased as response to topical prednisolone treatment in distal ulcerative colitis and proctitis.
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    ABSTRACT: The local release of human neutrophil lipocalin, considered to be highly specific for neutrophil granulocyte activation, and interleukin-8 and tumor necrosis factor-alpha were studied in 11 patients with distal ulcerative colitis and proctitis before and during treatment with steroid enemas. A rectal perfusion technique for sampling and specific immunoassays for analysis were used. In responders (N = 8) the concentrations of all proteins decreased during the study. There was a close correlation between human neutrophil lipocalin concentrations and treatment response. Tumor necrosis factor-alpha showed an initial decline in concentrations irrespective of treatment outcome and preceded the decline of human neutrophil lipocalin and interleukin-8. We conclude that decreased neutrophil degranulation is correlated with treatment outcome. Furthermore, an important role of tumor necrosis factor-alpha in the process of stimulating neutrophil activation and degranulation in ulcerative colitis is suggested.
    Digestive Diseases and Sciences 10/2002; 47(9):2064-9. · 2.12 Impact Factor
  • Article: A new method for the quantification of neutrophil and eosinophil cationic proteins in feces: establishment of normal levels and clinical application in patients with inflammatory bowel disease.
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    ABSTRACT: The aims of this study were 1) to develop a valid method for the measurement of the eosinophil proteins eosinophil cationic protein (ECP) and eosinophil protein X (EPX) and neutrophil proteins myeloperoxidase and human neutrophil lipocalin (HNL) in feces and 2) to investigate their potential role as disease activity markers in inflammatory bowel disease (IBD). Feces samples were obtained from 44 apparently healthy individuals (HIs), 18 patients with IBD (11 with ulcerative colitis [UC] and seven with Crohn's disease [CD]), and three with collagen colitis. The granulocyte markers were measured using immunoassays in supernatants from processed feces. ECP, myeloperoxidase, and, to a lesser degree, EPX and HNL were bound to the solid part of feces. However, feces homogenized in an extraction buffer containing the cationic detergent N-cetyl-N,N,N-trimethylammonium bromide allowed an efficient recovery of the proteins (i.e., up to 100-fold increased levels compared to homogenization in saline). All four proteins were stable for at least 7 days at +6 degrees C and at least 3 days at +22 degrees C. The normal fecal geometric mean (95th percentile) levels of ECP, EPX, myeloperoxidase, and HNL were estimated to be, respectively, 1.69 microg/g (6.41), 0.57 microg/g (1.72), 3.54 microg/g (8.77), and 1.97 microg/g (4.91). Markedly increased feces levels of all markers (p < 0.0002), compared to HIs and CD patients, were observed in UC. However, the marker levels in CD patients were significantly increased relative to HIs (p < 0.05 to p < 0.0002). Increased levels of HNL and myeloperoxidase were also observed in the three collagen colitis patients. The discriminative capability between UC patients and HIs was somewhat superior for EPX and myeloperoxidase. The method described here takes into account the molecular properties of the granule proteins and the heterogeneity in feces consistency, which is a prerequisite for a valid and reproducible measurement of cationic granule proteins. We suggest that EPX and myeloperoxidase, when applied in IBD, are the best eosinophil and neutrophil markers for studying GI inflammation.
    The American Journal of Gastroenterology 07/2002; 97(7):1755-62. · 7.28 Impact Factor
  • Article: IL-5 and TNF-α Participate in Recruitment of Eosinophils to Intestinal Mucosa in Ulcerative Colitis
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    ABSTRACT: There is an increased influx of activated eosinophils to the intestinal mucosa in active ulcerative colitis, and an increased release of eosinophil-derived proteins, such as ECP, has also been observed. These findings indicate that eosinophils may contribute to tissue damage and intestinal inflammation in this disease. The relative importance of different chemotactic factors and the impact of steroid treatment on their effect in active ulcerative colitis are not known. We measured the eosinophil chemotactic activity in perfusion fluids from 11 patients with ulcerative colitis before and after steroid treatment and from 7 control patients. The effect of neutralizing antibodies to IL-5 and -8, RANTES, eotaxin, MCP-3, TNF-, GM-CSF was investigated. The chemotactic activity was higher in perfusion fluids from patients than from controls (P = 0.0043). Anti-IL-5 (P = 0.005) and -TNF- (P = 0.017) inhibited the activity in perfusion fluids obtained before treatment. Steroid treatment prevented the effect of all antibodies but had no significant effect on the chemotactic activity. The chemotactic activity correlated with the levels of eosinophil granule proteins in the perfusion fluids. In conclusion, in ulcerative colitis, eosinophils are attracted to the intestinal tissue by chemotactic factors, of which IL-5 and TNF- may be the most prominent steroid-sensitive ones. The steroid-insensitive chemotactic activities remain unidentified.
    Digestive Diseases and Sciences 08/2001; 46(9):2004-2009. · 2.12 Impact Factor
  • Article: Regional Rectal Perfusion: A New in Vivo Approach to Study Rectal Drug Absorption in Man
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    ABSTRACT: Background: In vivo permeability measurements of drugs in the colonic/rectal region in humans are difficult. A new instrument for the perfusion of a defined and closed segment in the colon/rectum was developed. The objective of this study was to evaluate its use for studying drug absorption mechanisms in the human rectum and to investigate the effect of transmucosal water absorption on drug permeability. Six healthy subjects participated at 2 separate occasions by using a modified system for segmental rectal perfusion. The system consisted of a multichannel tube with inflatable balloons and was endoscopically introduced into the rectum. The technique was considered acceptable by the following criteria; (a) high and reproducible recovery of PEG 4000, (b) stable residence time of the solution within the test segment, (c) flux of electrolytes that agrees with previous reports, (d) mass-balance absorption of antipyrine across the rectal barrier, (e) and good acceptability to the subjects. The permeability of antipyrine in the rectal region was increased by inducing net water absorption. D-glucose was not absorbed during any study periods. The present technique is valuable for studying drug absorption from the human rectum.
    Pharmaceutical Research 02/1995; 12(3):426-432. · 4.09 Impact Factor
  • Article: Neutrophil and eosinophil granule proteins as markers of response to local prednisolone treatment in distal ulcerative colitis and proctitis
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    ABSTRACT: OBJECTIVE:The pathophysiological role of neutrophil and eosinophil granulocytes in relation to steroid enema treatment was studied in patients with distal ulcerative colitis and proctitis.METHODS:The rectal release of the neutrophil (myeloperoxidase, MPO), and eosinophil (eosinophilic cationic protein, ECP and eosinophil peroxidase, EPO) granule constituents were measured in 11 patients using intraluminal segmental perfusion of the rectum. The released amounts of MPO, ECP, and EPO in the perfusion fluids were determined by radioimmunoassays before and during prednisolone enema treatment and related to clinical, endoscopical, and histopathological data in addition to treatment outcome.RESULTS:Clinical activity and particularly endoscopic activity correlated well with intraluminal MPO concentrations both before and during treatment. At the end of the study, eight of 11 patients fulfilled predefined response criteria; all responding patients had significant decrease of MPO concentrations (p < 0.01). This decline of MPO concentration was seen after 7 days of treatment (p < 0.05) in the response group and often occurred before clinical improvement. There was a nonsignificant trend toward a decrease in the concentrations of ECP and EPO at the end of treatment in responders.CONCLUSIONS:In patients with distal ulcerative colitis and proctitis, neutrophil activation determined, as a release of MPO is an early marker of treatment response. Eosinophil activation measured as a release of ECP and EPO correlates with endoscopic activity, but the relationship to treatment outcome is less clear.
    The American Journal of Gastroenterology.