| 1. |
- Münch, Andreas
(författare)
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Collagenous colitis : The influence of inflammation and bile acids on intestinal barrier function
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background and aims: Collagenous colitis (CC) is a diarrheal disorder with an incidence rate of 5-6/100000 inhabitants, affecting mainly middle-aged women. The diagnosis is made by histology of the colonic mucosa. Classical findings are a thickened subepithelial collagenous layer and chronic inflammation in the lamina propria. In inflammatory bowel disease (IBD) the mucosal barrier function is important in pathogenesis. The main purpose of the thesis was therefore to describe the barrier function in CC. The cause of CC is uncertain but the condition seems to be associated with bile acid malabsorption. Increased faecal bile acids are known to induce diarrhea. In functional studies the influence of bile acids on mucosal permeability in biopsies of healthy human individuals and in patients with CC was investigated.Methods and patients: In the first paper a single patient with intractable CC was examined before surgery, with loop-ileostomy and after bowel reconstruction. For the other studies a total of 25 patients with CC were included (20 women, 5 men, mean age 66 years). There were three groups (14 patients in clinical remission without medical treatment, 11 with active disease, and 8 of these again after 6 weeks of budesonide treatment); 17 individuals with normal histology served as controls. Endoscopic biopsies from the sigmoid colon were mounted in modified Ussing chambers and assessed for short-circuit current (Isc), transepithelial resistance (TER), and transmucosal passage of chemically killed E. coli K12 after addition of chenodeoxycholic acid (CDCA) and deoxycholic acid (DCA). The biopsies were further investigated with confocal microscopy to assess bacterial transepithelial passage.Results: Para- and transcellular permeability was increased in active CC, but normalized with histological improvement due to faecal stream diversion. After bowel reconstruction, permeability to CrEDTA and HRP increased again.In CC, bacterial uptake in colonic biopsies was significantly higher in all groups than in controls. Despite significant alleviation of symptoms, budesonide did not normalize the increased bacterial passage. Histology was unchanged after 6 weeks of budesonide treatment. DCA augmented mucosal permeability to CrEDTA in a dose-dependent manner and even such a low dose as 100 μmol/l DCA increased bacterial uptake significantly. The combination of bile acids and E.coli K12 had additive effects on TER.100 μmol/l CDCA and DCA increased bacterial uptake in biopsies of CC patients in remission 4-fold, but had no additive effect on biopsies from patients with active disease. Furthermore, patients in clinical remission on budesonide treatment showed no bile acidinduced effects on E.coli K12 passage.Conclusion: Collagenous colitis presents with increased para/transcellular permeability and bacterial uptake, irrespective of disease activity or budesonide treatment, signifying an underlying mucosal barrier defect. Faecal stream diversion can normalize the barrier dysfunction, but budesonide does not, despite its beneficial clinical effects which alleviate diarrhea or bowel symptoms. Bile acids in physiological concentrations have the potential to augment bacterial uptake, especially in mucosa from CC patients in remission. Budesonide treatment appears to counteract the bile acid induced mucosal impairment. These detrimental effects of bile acids on mucosal barrier function might facilitate initiation and perpetuation of mucosal inflammation in CC.
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| 2. |
- Ström, Linda, 1985, et al.
(författare)
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Catalytically Active Pd–Ag Alloy Nanoparticles Synthesized in Microemulsion Template
- 2018
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 1520-5827 .- 0743-7463. ; 34:33, s. 9754-9761
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Tidskriftsartikel (refereegranskat)abstract
- This work investigates the possibility to form catalytically active bimetallic Pd–Ag nanoparticles synthesized in the water pools of a reversed microemulsion using methanol, a more environmental- and user-friendly reductant compared to hydrazine or sodium borohydride, which are commonly used for this type of synthesis. The nanoparticles were characterized with regards to crystallinity and size by X-ray diffraction and transmission electron microscopy. CO chemisorption and oxidation followed by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used for investigating the elemental composition of the surface and catalytic activity, respectively. Moreover, the structural composition of the bimetallic particles was determined by scanning transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy. The particles were shown to be crystalline nanoalloys of around 5–12 nm. CO adsorption followed by in situ DRIFTS suggests that the particle surfaces are composed of the same Pd–Ag ratios as the entire particles, regardless of elemental ratio (i.e., no core–shell structures can be detected). This is also shown by numerical simulations using a Monte Carlo based model. Furthermore, CO oxidation confirms that the synthesized particles are catalytically active.
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| 3. |
- Ström, Linda, 1985, et al.
(författare)
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Quantification of urea-spray non-uniformity effects on the H2-assisted NO reduction and NH3 slip over an Ag/Al2O3 catalyst
- 2015
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 75, s. 2317-2322
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Konferensbidrag (refereegranskat)abstract
- Selective catalytic reduction of nitrogen oxides (NOx) with ammonia (NH3-SCR) is an efficient technology for lean NOx removal in automotive applications. In the current work, a kinetic model for hydrogen-assisted NH3-SCR over a silver-alumina (Ag/Al2O3) monolith catalyst is adapted to the corresponding experimental results. The degree of non-uniformity in the NH3 dose to individual catalyst channels during operation of a urea-SCR system is also investigated and the NH3 dose probability distribution functions are derived. The effects of NH3 non-uniformity on the NO conversion and NH3 slip are studied over an otherwise optimal Ag/Al2O3 system. Above the stoichiometric point, the NH3 slip is shown to increase almost linearly with increasing NH3 dosage. Channels that receive significantly lower NH3 dose than the stoichiometric one exhibit low NO conversion, whereas there is no discernable increase in the NO conversion above an NH3 dose four times the average. These results highlight the importance of the interaction between the design of the NH3 dosing system and the performance of the catalytic system.
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| 4. |
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| 5. |
- Agebratt, Christian, et al.
(författare)
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A Randomized Study of the Effects of Additional Fruit and Nuts Consumption on Hepatic Fat Content, Cardiovascular Risk Factors and Basal Metabolic Rate
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:1, s. e0147149-
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundFruit has since long been advocated as a healthy source of many nutrients, however, the high content of sugars in fruit might be a concern.ObjectivesTo study effects of an increased fruit intake compared with similar amount of extra calories from nuts in humans.MethodsThirty healthy non-obese participants were randomized to either supplement the diet with fruits or nuts, each at +7 kcal/kg bodyweight/day for two months. Major endpoints were change of hepatic fat content (HFC, by magnetic resonance imaging, MRI), basal metabolic rate (BMR, with indirect calorimetry) and cardiovascular risk markers.ResultsWeight gain was numerically similar in both groups although only statistically significant in the group randomized to nuts (fruit: from 22.15±1.61 kg/m2 to 22.30±1.7 kg/m2, p = 0.24 nuts: from 22.54±2.26 kg/m2 to 22.73±2.28 kg/m2, p = 0.045). On the other hand BMR increased in the nut group only (p = 0.028). Only the nut group reported a net increase of calories (from 2519±721 kcal/day to 2763±595 kcal/day, p = 0.035) according to 3-day food registrations. Despite an almost three-fold reported increased fructose-intake in the fruit group (from 9.1±6.0 gram/day to 25.6±9.6 gram/day, p<0.0001, nuts: from 12.4±5.7 gram/day to 6.5±5.3 gram/day, p = 0.007) there was no change of HFC. The numerical increase in fasting insulin was statistical significant only in the fruit group (from 7.73±3.1 pmol/l to 8.81±2.9 pmol/l, p = 0.018, nuts: from 7.29±2.9 pmol/l to 8.62±3.0 pmol/l, p = 0.14). Levels of vitamin C increased in both groups while α-tocopherol/cholesterol-ratio increased only in the fruit group.ConclusionsAlthough BMR increased in the nut-group only this was not linked with differences in weight gain between groups which potentially could be explained by the lack of reported net caloric increase in the fruit group. In healthy non-obese individuals an increased fruit intake seems safe from cardiovascular risk perspective, including measurement of HFC by MRI.
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| 6. |
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| 7. |
- Almer, Sven, 1953-, et al.
(författare)
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Leukocyte scintigraphy compared to intraoperative small bowel enteroscopy and laparotomy findings in Crohn's disease
- 2007
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Ingår i: Inflammatory Bowel Diseases. - : Oxford University Press (OUP). - 1078-0998 .- 1536-4844. ; 13:2, s. 164-174
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Tidskriftsartikel (refereegranskat)abstract
- Background: Leukocyte scintigraphy is a noninvasive investigation to assess inflammation. We evaluated the utility of labeled leukocytes to detect small bowel inflammation and disease complications in Crohn's disease and compared it to whole small bowel enteroscopy and laparotomy findings.Methods: Scintigraphy with technetium-99m exametazime-labeled leukocytes was prospectively performed in 48 patients with Crohn's disease a few days before laparotomy; 41 also had an intraoperative small bowel enteroscopy. The same procedures were performed in 8 control patients. Independent grading of scans was compared with the results of enteroscopy and with surgical, histopathologic, and clinical data.Results: In the 8 control patients leukocyte scan, endoscopy, and histopathology were all negative for the small bowel. In patients with Crohn's disease and small bowel inflammation seen at enteroscopy and/or laparotomy (n = 39) the scan was positive in 33. In 8 patients without macroscopic small bowel inflammation, the scan was positive for the small bowel in 3 patients; at histology, 2 of 3 had inflammation. When combining results for patients and controls, the sensitivity of leukocyte scan for macroscopically evident small bowel inflammation was 0.85, specificity 0.81, accuracy 0.84, positive predictive value 0.92, and negative predictive value 0.68. Scintigraphy detected inflammatory lesions not known before laparotomy in 16 of 47 (34%) Crohn's disease patients and showed uptake in 25 of 35 (71%) bowel strictures. It was diagnostic regarding 4 of 8 abscesses and 9 of 15 fistulas. In 6 patients (13%) lesions first demonstrated by leukocyte scintigraphy were treated during the surgery performed.Conclusions: Leukocyte scintigraphy reliably detects small bowel inflammation in Crohn's disease. It gives additional information on the presence of inflammatory lesions in a fraction of patients planned for surgery.
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| 8. |
- Andersson, Peter, et al.
(författare)
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Low symptomatic load in Crohn's disease with surgery and medicine as complementary treatments
- 1998
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Ingår i: Scandinavian Journal of Gastroenterology. - : Informa Healthcare. - 0036-5521 .- 1502-7708. ; 33:4, s. 423-429
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Tidskriftsartikel (refereegranskat)abstract
- Background: The treatment of Crohn's disease has changed owing to the recognition of its chronicity. Medical maintenance treatment and limited resections have evolved as major concepts of management, regarded as complementary, and both aim at reducing the symptoms.Methods: We investigated the symptomatic load in Crohn's disease as reflected in a cross-sectional study of the symptom index, physicians' assessment, and the patients' perception of health. A cohort of 212 patients from the primary catchment area and 125 referred patients were studied.Results: Of catchment area patients, 83% were receiving medication, and the annual rate of abdominal surgery was 5.7%. Corresponding figures for the referred patients were 82% and 10.3%. According to the symptom index, 87% of catchment area patients were in remission or had only mild symptoms; according to the physicians' assessment, 90% were. The patients' median perception of health was 90% of perfect health according to the visual analogue scale. The figures were similar for referred patients, except that referrals were considered more diseased by the physician.Conclusion: The great majority of patients with Crohn's disease are able to live in remission or experience only mild symptoms.
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| 9. |
- Bednarska, Olga, et al.
(författare)
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Intraepithelial lymphocyte distribution differs between the bulb and the second part of duodenum
- 2013
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Ingår i: BMC Gastroenterology. - : BioMed Central. - 1471-230X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundEvaluation of intraepithelial duodenal lymphocytosis (IDL) is important in celiac disease (CD). There is no established cut-off value for increased number of IELs in the bulb.We therefore investigated the relation between IEL counts in the bulb and duodenal specimens in non-celiac subjects.MethodsThe number of CD3+ IELs was determined in specimens from the second part of the duodenum and from the bulb in 34 non-celiac subjects. The numbers of IELs in the villus tip and sides were counted and the quotient tip/side was calculated. HLA DQ2/DQ8 and serum antibodies against transglutaminase were analysed.ResultsThe mean number of IELs per 100 enterocytes (95% CI) in specimens was 14.7 (11.8-17.6) in the bulb, and 21.2 (17.0-25.5) in the second part of the duodenum (p<0.01). There was no difference in IEL count or distribution comparing patients carrying or lacking HLA DQ2/DQ8.ConclusionsIEL count in non-celiac, HLA DQ2/DQ8 positive or negative patients is significantly lower in the bulb than in the second part of the duodenum. These findings implicate that the site of biopsy should be taken into account when considering duodenal lymphocytosis.
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| 10. |
- Bednarska, Olga, 1973-
(författare)
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Peripheral and Central Mechanisms in Irritable Bowel Syndrome : in search of links
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Irritable bowel syndrome (IBS) is a chronic visceral pain disorder with female predominance, characterized by recurrent abdominal pain and disturbed bowel habits in the absence of an identifiable organic cause. This prevalent and debilitating disease, which accounts for a substantial economic and individual burden, lacks exact diagnostic tools and effective treatment, since its pathophysiology remains uncertain. The bidirectional and multilayered brain-gut axis is a well-established disease model, however, the interactions between central and peripheral mechanisms along the brain-gut axis remain incompletely understood. One of the welldescribed triggering factors, yet accounting for only a fraction of IBS prevalence, is bacterial gastroenteritis that affects mucosal barrier function. Altered gut microbiota composition as well as disturbed intestinal mucosal barrier function and its neuroimmune regulation have been reported in IBS, however, the impact of live bacteria, neither commensal nor pathogenic, on intestinal barrier has not been studied yet. Furthermore, abnormal central processing of visceral sensations and psychological factors such as maladaptive coping have previously been suggested as centrally-mediated pathophysiological mechanisms of importance in IBS. Brain imaging studies have demonstrated an imbalance in descending pain modulatory networks and alterations in brain regions associated with interoceptive awareness and pain processing and modulation, particularly in anterior insula (aINS), although biochemical changes putatively underlying these central alterations remain poorly understood. Most importantly, however, possible associations between these documented changes on central and peripheral levels, which may as complex interactions contribute to disease onset and chronification of symptoms, are widely unknown.This thesis aimed to investigate the peripheral and central mechanisms in women with IBS compared to female healthy controls (HC) and to explore possible mutual associations between these mechanisms.In Paper I, we studied paracellular permeability and passage of live bacteria, both commensal and pathogenic through colonic biopsies mounted in Ussing chambers. We explored the regulation of the mucosal barrier function by mast cells and the neuropeptide vasoactive intestinal polypeptide (VIP) as well as a correlation between mucosal permeability and gastrointestinal and psychological symptoms. We observed increased paracellular permeability and the passage of commensal and pathogenic live bacteria in patients with IBS compared with HC, which was diminished by blocking the VIP receptors as well as after stabilizing mast cells in both groups. Moreover, higher paracellular permeability was associated with less somatic and psychological symptoms in patients.In Paper II, we aimed to determine the association between colonic mucosa paracellular permeability and structural and resting state functional brain connectivity. We demonstrated different patterns of associations between mucosa permeability and functional and structural brain connectivity in IBS patients compared to HC. Specifically, lower paracellular permeability in IBS, similar to the levels detected in HC, was associated with more severe IBS symptoms and increased functional and structural connectivity between intrinsic brain resting state network and descending pain modulation brain regions. Our findings further suggested that this association between mucosa permeability and functional brain connectivity was mainly mediated by coping strategies.In Paper III, we investigated putative alterations in excitatory and inhibitory neurotransmission of aINS, as the brain’s key node of the salience network crucially involved in cognitive control, in IBS patients relative to HC and addressed possible connections with both symptoms and psychological factors. We found decreased concentrations of the excitatory neurotransmitter Glx in bilateral aINS in IBS patients compared to HC, while inhibitory neurotransmitter GABA+ levels were comparable. Further, we demonstrated hemisphere-specific associations between abdominal pain, coping and aINS excitatory neurotransmitter concentration.In conclusion, this thesis broadens the knowledge on peripheral and central mechanisms in IBS and presents novel findings that bring together the ends of brain-gut axis. Our results depict association between mucosal permeability, IBS symptoms and functional and structural connectivity engaging brain regions involved in emotion and pain modulation as well as underlying neurotransmitter alterations.
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| 11. |
- Bednarska, Olga, et al.
(författare)
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Vasoactive Intestinal Polypeptide and Mast Cells Regulate Increased Passage of Colonic Bacteria in Patients With Irritable Bowel Syndrome
- 2017
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Ingår i: Gastroenterology. - : W B SAUNDERS CO-ELSEVIER INC. - 0016-5085 .- 1528-0012. ; 153:4, s. 948-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND amp; AIMS: Irritable bowel syndrome (IBS) is associated with intestinal dysbiosis and symptoms of IBS develop following gastroenteritis. We aimed to study the passage of live bacteria through the colonic epithelium, and determine the role of mast cells (MCs) and vasoactive intestinal polypeptide (VIP) in barrier regulation in IBS and healthy individuals. METHODS: Colon biopsies from 32 women with IBS and 15 age-matched healthy women (controls) were mounted in Ussing chambers; we measured numbers of fluorescently labeled Escherichia coli HS and Salmonella typhimurium that passed through from the mucosal side to the serosal side of the tissue. Some biopsies were exposed to agents that block the VIP receptors (VPAC1 and VPAC2) or MCs. Levels of VIP and tryptase were measured in plasma and biopsy lysates. Number of MCs and MCs that express VIP or VIP receptors were quantified by immunofluorescence. Biopsies from an additional 5 patients with IBS and 4 controls were mounted in chambers and Salmonella were added; we studied passage routes through the epithelium by transmission electron microscopy and expression of tight junctions by confocal microscopy. RESULTS: In colon biopsies from patients with IBS, larger numbers of E coli HS and S typhimurium passed through the epithelium than in biopsies from controls (P amp;lt;.0005). In transmission electron microscopy analyses, bacteria were found to cross the epithelium via only the transcellular route. Bacterial passage was reduced in biopsies from patients with IBS and controls after addition of antibodies against VPACs or ketotifen, which inhibits MCs. Plasma samples from patients with IBS had higher levels of VIP than plasma samples from controls. Biopsies from patients with IBS had higher levels of tryptase, larger numbers of MCs, and a higher percentage of MCs that express VPAC1 than biopsies from controls. In biopsies from patients with IBS, addition of Salmonella significantly reduced levels of occludin; subsequent addition of ketotifen significantly reversed this effect. CONCLUSIONS: We found that colonic epithelium tissues from patients with IBS have increased translocation of commensal and pathogenic live bacteria compared with controls. The mechanisms of increased translocation include MCs and VIP.
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| 12. |
- Bergeron, Tor, et al.
(författare)
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'Fimbulvinter'
- 1956
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Ingår i: Fornvännen. - 0015-7813 .- 1404-9430. ; 51, s. 1-18
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 13. |
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| 14. |
- Bernin, Diana, 1979, et al.
(författare)
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Microstructure of polymer hydrogels studied by pulsed field gradient NMR diffusion and TEM methods
- 2011
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 7:12, s. 5711-5716
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Tidskriftsartikel (refereegranskat)abstract
- The microstructure of various alginate gels have been studied by pulsed field gradient NMR (PFG NMR) and transmission electron microscopy (TEM). The reduced diffusivity of dendrimer diffusion within the gels has been obtained from PFG NMR diffusion experiments. The polymer strand radius, an important microstructural property, has been extracted from various diffusion models. The results agree well with the polymer strand radii obtained from image analysis of the corresponding TEM micrographs.
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| 15. |
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| 16. |
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| 17. |
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| 18. |
- Daferera, Niki, et al.
(författare)
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Collagenous Colitis Mucosa Is Characterized by an Expansion of Nonsuppressive FoxP3(+) T Helper Cells
- 2021
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Ingår i: Inflammatory Bowel Diseases. - : OXFORD UNIV PRESS INC. - 1078-0998 .- 1536-4844. ; 27:9, s. 1482-1490
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Tidskriftsartikel (refereegranskat)abstract
- Background and Aim: Increased frequencies of T regulatory (Treg) cells, key players in immune regulation, have been reported in inflammatory bowel diseases, including collagenous colitis (CC). However, traditional Treg identification techniques might have misinterpreted the frequencies of Treg cells in CC. Thus, we investigated the presence of genuine Treg cells in CC. Methods: Treg cells were analyzed in mucosal and peripheral blood samples of CC patients before and during treatment with the corticosteroid drug budesonide and in healthy controls. Samples were analyzed by flow cytometry by classifying CD3(+) CD4(+) cells as activated FoxP3(high)CD45RA. Treg cells, resting FoxP3(dim)CD45RA(+) Treg cells, and nonsuppressive FoxP3(dim)CD45RA-T helper cells. Traditional gating strategies that classified Treg cells as CD25(high)CD127(lo)(w), FoxP3(+)CD127(low), and CD4(+)CD25(+)FoxP3(+) were also used to facilitate comparison with previous studies. Results: Activated and resting Treg cell frequencies did not change in active CC mucosa or peripheral blood and were not affected by budesonide treatment. Instead, nonsuppressive FoxP3(dim)CD45RA-T helper cells were increased in active CC mucosa, and budesonide helped restore them to normal levels. In contrast, traditional Treg cell gating strategies resulted in increased Treg cell frequencies in active CC mucosa. No alterations were found in peripheral blood samples, independently of patient treatment or gating techniques. Conclusion: Previously reported increase of Treg cells is a result of incomplete Treg phenotyping, which included nonsuppressive FoxP3(dim)CD45RA - T helper cells. Because budesonide did not affect Treg percentage, its therapeutic effect in CC might involve alternative mechanisms.
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| 19. |
- Daferera, Niki, et al.
(författare)
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Fecal stream diversion and mucosal cytokine levels in collagenous colitis : A case report
- 2015
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Ingår i: World Journal of Gastroenterology. - Pleasanton, USA : Baishideng Publishing Group Inc.. - 1007-9327 .- 2219-2840. ; 21:19, s. 6065-6071
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Tidskriftsartikel (refereegranskat)abstract
- In this case report, we examined the levels of cytokines expressed before and during fecal stream diversion and after intestinal continuity was restored in a patient with collagenous colitis. We report the case of a 46-year-old woman with chronic, active collagenous colitis who either failed to achieve clinical remission or experienced adverse effects with the following drugs: loperamide, cholestyramine, budesonide, methotrexate and adalimumab. Due to the intractable nature of the disease and because the patient was having up to 15 watery bowel movements per day, she underwent a temporary ileostomy. Colonic biopsies were analyzed for mucosal cytokine protein levels before and during fecal stream diversion and after intestinal continuity was restored. Mucosal protein levels of interleukin (IL)-1β, IL-2, IL-6, IL-12, IL-17 A, IL-23, TNF, IFN-γ, IL-4, IL-5, IL-10 and IL-13 were all higher during active disease and decreased to non-detectable or considerably lower levels during fecal stream diversion. One month after the restoration of bowel continuity, when the patient experienced a relapse of symptoms, IL-2, IL-23 and IL-21 levels were again increased. Our results indicate that fecal stream diversion in this patient suppressed the levels of all cytokines analyzed in colonic biopsies. With the recurrence of clinical symptoms and histological changes after bowel reconstruction, the levels of primarily proinflammatory cytokines increased. Our findings support the hypothesis that a luminal factor triggers the inflammation observed in collagenous colitis.
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| 20. |
- Daferera, Niki, et al.
(författare)
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Mucosa associated invariant T and natural killer cells in active and budesonide treated collagenous colitis patients
- 2022
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Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionCollagenous colitis (CC) is an inflammatory bowel disease, which usually responds to budesonide treatment. Our aim was to study the immunological background of the disease. MethodsAnalyses of peripheral and mucosal MAIT (mucosa associated invariant T cells) and NK (natural killer) cells were performed with flow cytometry. Numbers of mucosal cells were calculated using immunohistochemistry. We studied the same patients with active untreated CC (au-CC) and again while in remission on budesonide treatment. Budesonide refractory patients and healthy controls were also included. The memory marker CD45R0 and activation marker CD154 and CD69 were used to further study the cells. Finally B cells, CD4(+) and CD8(+) T cells were also analysed. ResultsThe percentages of circulating CD56(dim)CD16(+) NK cells as well as MAIT cells (CD3(+)TCRVa7.2(+)CD161(+)) were decreased in au-CC compared to healthy controls. This difference was not seen in the mucosa; where we instead found increased numbers of mucosal CD4(+) T cells and CD8(+) T cells in au-CC. Mucosal immune cell numbers were not affected by budesonide treatment. In refractory CC we found increased mucosal numbers of MAIT cells, CD4(+) and CD8(+) T cells compared to au-CC. DiscussionPatients with active collagenous colitis have lower percentages of circulating MAIT and NK cells. However, there was no change of these cells in the colonic mucosa. Most mucosal cell populations were increased in budesonide refractory as compared to au-CC patients, particularly the number of MAIT cells. This may indicate that T cell targeting therapy could be an alternative in budesonide refractory CC.
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| 21. |
- Dahle, Charlotte, et al.
(författare)
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Antibodies against deamidated gliadin peptides identify adult coeliac disease patients negative for antibodies against endomysium and tissue transglutaminase
- 2010
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Ingår i: Alimentary Pharmacology and Therapeutics. - : Blackwell Publishing Ltd. - 0269-2813 .- 1365-2036. ; 32:2, s. 254-260
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Tidskriftsartikel (refereegranskat)abstract
- Background This study was done to evaluate the diagnostic utility of antibodies against deamidated gliadin peptides compared to traditional markers for coeliac disease. Aim To evaluate diagnostic utility of antibodies against deamidated gliadin peptide (DGP). Methods Sera from 176 adults, referred for endoscopy without previous analysis of antibodies against tissue transglutaminase (tTG) or endomysium (EmA), were retrospectively analysed by ELISAs detecting IgA/IgG antibodies against DGP or a mixture of DGP and tTG, and compared with IgA-tTG and EmA. Seventy-nine individuals were diagnosed with coeliac disease. Results Receiver operating characteristic analyses verified the manufacturers cut-off limits except for IgA/IgG-DGP/ tTG. In sera without IgA deficiency, the sensitivity was higher for IgA/IgG-DGP (0.85-0.87) compared with IgA-tTg (0.76) and EmA (0.61). All tests showed high specificity (0.95-1.00). Eighteen coeliac disease-sera were negative regarding IgA-tTG, nine of which were positive for IgA/IgG-DGP. Sera from coeliac disease-patients greater than70 years were more often negative for IgA-tTG (50%) and IgA/IgG-DGP (36%) than younger patients (15% and 8% respectively) (P less than 0.01). Three of the four IgA-deficient patients were positive in the IgA/IgG-DGP assay. Conclusions In this study of patients unselected regarding IgA-tTg/EmA, thus unbiased in this respect, IgA/IgG-DGP identified adult coeliac disease patients negative for antibodies against endomysium and tissue transglutaminase. Serology is often negative in elderly patients with coeliac disease; a small bowel biopsy should therefore be performed generously before coeliac disease is excluded.
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| 22. |
- Edgren, Aina, 1995, et al.
(författare)
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High temperature compression of Mo(Si,Al)2-Al2O3 composites
- 2023
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Ingår i: Materials Science & Engineering. - : Elsevier. - 0921-5093 .- 1873-4936. ; 865
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the effect on high temperature of mechanical properties of adding Al2O3 particles to polycrystalline Mo(Si,Al)2. Mo(Si,Al)2-Al2O3 composites, containing 0–25 wt% Al2O3 particles have been compression tested at 1300 °C, and the microstructure after deformation was studied using electron backscatter diffraction. It was shown that even small amounts (5 wt%) of Al2O3 particles resulted in a grain-refined material through inhibition of grain growth during sintering, which lead to lower flow stresses compared to the coarse-grained Al2O3-free material. The inverse grain size effect and post-test microstructure investigations suggest that creep-like deformation mechanisms dominate in fine grained Mo(Si,Al)2-Al2O3 composites at 1300 °C. In the materials containing 5–15 wt% Al2O3, the maximum stress decreased with increasing Al2O3 content. In materials with higher Al2O3 additions, the maximum stress increased with the Al2O3 addition, but did not reach the strength levels in the Al2O3-free reference material. It is suggested that the deformation behaviour is affected by electroplasticity effects as resistive heating was used. Electroplasticity contributes to the decrease in maximum stress observed in the lower Al2O3 containing materials, while this is outweighed by particle strengthening at higher Al2O3 contents.
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| 23. |
- Edgren, Aina, et al.
(författare)
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High temperature deformation of polycrystalline C40 Mo(Si,Al)2
- 2022
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Ingår i: Materials Science & Engineering. - : Elsevier. - 0921-5093 .- 1873-4936. ; 849
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Tidskriftsartikel (refereegranskat)abstract
- Polycrystalline Mo(Si,Al) with C40 crystal structure was deformed in compression with a strain rate of 10−4 s−1 at 1300 °C. The specimens were deformed to a strain of 10%–15% and showed maximum stresses around 150 MPa prior to pronounced softening. No crack formation or significant increase in porosity could be observed. Post-test microstructure analysis revealed that the material was inhomogeneously deformed on both inter- and intragranular levels. Dynamic recrystallization occurred alongside low angle grain boundary formation in highly deformed grains. Furthermore, complex intragranular deformation fields suggest that slip systems other than ⟨2̄1̄10⟩ [0001] may be active during deformation.
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| 24. |
- Ekstrom, Magnus, et al.
(författare)
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Trends in Cause-Specific Mortality in Oxygen-dependent Chronic Obstructive Pulmonary Disease
- 2011
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Ingår i: American Journal of Respiratory and Critical Care Medicine. - 1535-4970. ; 183:8, s. 1032-1036
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: Since the introduction of long-term oxygen treatment (LTOT) in chronic obstructive pulmonary disease (COPD) with chronic hypoxia, the proportion of women and the age of patients starting LTOT have increased markedly. We hypothesize that this might have led to shifts in the causes of death over time. Objectives: To test for time trends in cause-specific mortality in COPD with LTOT. Methods: Patients starting LTOT for COPD in Sweden between January 1, 1987 and December 31, 2004 were included in a national prospective study and monitored until withdrawal of LTOT, death, or December 31, 2004. The primary end point was cause of death obtained from the Swedish Causes of Death Register. Measurements and Main Results: A total of 7,628 patients (53% women) were monitored for a median of 1.7 years (range, 0-18.0 yr). No patient was lost to follow-up and 5,457 patients died during the study. The crude overall mortality increased by 1.6%/year (95% confidence interval [CI], 0.9-2.2%/yr; P < 0.001). The absolute risk of death increased for circulatory disease by 2.8%/year (95% CI, 1.3-4.3%/yr; P < 0.001) and for digestive organ disease by 7.8%/year (95% CI, 1.9-14.0%/ yr; P = 0.009). The absolute risk of death decreased for respiratory disease by 2.7%/year (95% CI, 2.0-3.3%/yr; P < 0.001) and for lung cancer by 3.4%/year (95% CI, 1.1-5.7%/yr; P = 0.004). Conclusions: In oxygen-dependent COPD, mortality has increased over time both overall and of nonrespiratory causes, including cardiovascular disease. This highlights the importance of optimized diagnostics and treatment of comorbidities to decrease morbidity and mortality.
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