| 1. |
- Bailey, D. L., et al.
(författare)
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Combined PET/MRI : Global Warming-Summary Report of the 6th International Workshop on PET/MRI, March 27-29, 2017, Tubingen, Germany
- 2018
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Ingår i: Molecular Imaging and Biology. - : SPRINGER. - 1536-1632 .- 1860-2002. ; 20:1, s. 4-20
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Forskningsöversikt (refereegranskat)abstract
- The 6th annual meeting to address key issues in positron emission tomography (PET)/magnetic resonance imaging (MRI) was held again in Tubingen, Germany, from March 27 to 29, 2017. Over three days of invited plenary lectures, round table discussions and dialogue board deliberations, participants critically assessed the current state of PET/MRI, both clinically and as a research tool, and attempted to chart future directions. The meeting addressed the use of PET/MRI and workflows in oncology, neurosciences, infection, inflammation and chronic pain syndromes, as well as deeper discussions about how best to characterise the tumour microenvironment, optimise the complementary information available from PET and MRI, and how advanced data mining and bioinformatics, as well as information from liquid biomarkers (circulating tumour cells and nucleic acids) and pathology, can be integrated to give a more complete characterisation of disease phenotype. Some issues that have dominated previous meetings, such as the accuracy of MR-based attenuation correction (AC) of the PET scan, were finally put to rest as having been adequately addressed for the majority of clinical situations. Likewise, the ability to standardise PET systems for use in multicentre trials was confirmed, thus removing a perceived barrier to larger clinical imaging trials. The meeting openly questioned whether PET/MRI should, in all cases, be used as a whole-body imaging modality or whether in many circumstances it would best be employed to give an in-depth study of previously identified disease in a single organ or region. The meeting concluded that there is still much work to be done in the integration of data from different fields and in developing a common language for all stakeholders involved. In addition, the participants advocated joint training and education for individuals who engage in routine PET/MRI. It was agreed that PET/MRI can enhance our understanding of normal and disrupted biology, and we are in a position to describe the in vivo nature of disease processes, metabolism, evolution of cancer and the monitoring of response to pharmacological interventions and therapies. As such, PET/MRI is a key to advancing medicine and patient care.
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| 2. |
- Keszthelyi, D., et al.
(författare)
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Revisiting concepts of visceral nociception in irritable bowel syndrome
- 2012
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Ingår i: European Journal of Pain. - : Wiley. - 1090-3801. ; 16:10, s. 1444-1454
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Forskningsöversikt (refereegranskat)abstract
- Background and Objective Irritable bowel syndrome (IBS) is a common disorder characterized by abdominal pain related to defecation with a change in bowel habit. Patients with IBS often exhibit increased visceral sensitivity, which can be tested clinically by rectal balloon distension procedures. This paper aims to give an overview of mechanisms involved in visceral hypersensitivity in IBS by reviewing recent literature. Databases and Data Treatment A literature search in the electronic databases Pubmed and MEDLINE was executed using the search terms visceral pain or visceral nociception or visceral hypersensitivity and irritable bowel syndrome. Both original articles and review articles were considered for data extraction. Results Recent advances in molecular neurophysiology provide knowledge to better understand the underlying mechanism in pain generation in the human gut, in particular, in IBS patients. Sensitization of peripheral nociceptive afferents, more specifically high-threshold afferents, has been proposed as one of the principle mechanism in the development of visceral hypersensitivity. On the other hand, central mechanisms also play an important role. In terms of clinical testing of visceral perception, considerable discrepancies remain, however, across different centres. Conclusion Alterations in the modulatory balance of pro- and antinociceptive central processing of noxious peripheral input may serve as in integrative hypothesis for explaining visceral hypersensitivity in IBS. Nevertheless, it remains troublesome to estimate the contribution of central and peripheral factors in visceral hypersensitivity, posing a challenge in determining effective therapeutic entities.
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| 3. |
- Vanhoutvin, S. A. L. W., et al.
(författare)
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Alternative procedure to shorten rectal barostat procedure for the assessment of rectal compliance and visceral perception : a feasibility study
- 2012
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Ingår i: Journal of gastroenterology. - : Springer-Verlag Tokyo Inc.. - 0944-1174 .- 1435-5922. ; 47:8, s. 896-903
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Barostat methodology is widely used for assessing visceral perception. Different barostat protocols are described with respect to the measurement of rectal compliance and visceral perception. The choice of protocols affects the duration, which is normally 60-90 min, and accuracy of the procedure. This study aimed to shorten the procedure by using the semi-random distension protocol for both compliance and visceral perception measurement and a correction based on rectal capacity (RC) instead of minimal distension pressure (MDP).METHODS: Twelve irritable bowel syndrome (IBS) patients (7 females) and 11 healthy controls (8 females) underwent a barostat procedure. Compliance was determined during both a staircase distension and a semi-random protocol. Visceral perception data were compared as a function of pressure or relative volume, corrected for MDP or RC, respectively.RESULTS: Compliance measurement using the semi-random protocol instead of the staircase distension protocol resulted in an overestimation in healthy volunteers, but not in IBS patients. The overall conclusion that IBS patients had a lower compliance compared to controls was not different between protocols. Data presentation of the visceral perception scores as a function of corrected volume instead of pressures corrected for MDP did not alter the conclusion that sensation scores in IBS patients were higher as compared to healthy controls.CONCLUSIONS: This study showed that barostat procedures may be shortened by approximately 20 min, without losing the ability to discriminate between healthy controls and IBS patients. A correction for RC instead of MDP may improve the accuracy of the procedure.
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| 4. |
- Vanhoutvin, S. A. L. W., et al.
(författare)
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The effects of butyrate enemas on visceral perception in healthy volunteers
- 2009
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Ingår i: Neurogastroenterology and Motility. - : Wiley-Blackwell Publishing Inc.. - 1350-1925 .- 1365-2982. ; 21:9, s. 952-e76
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Tidskriftsartikel (refereegranskat)abstract
- Fermentation of dietary fibres by colonic microbes leads to the production of short chain fatty acids (mainly propionate, butyrate and acetate), which are utilized by the colonic mucosa. Previous studies showed positive effects of butyrate on parameters of oxidative stress, inflammation and apoptosis. Recent studies in rats, however, showed that butyrate increased visceral sensitivity. The aim of this study was to determine the effects of physiologically relevant concentrations of butyrate on visceral perception in healthy human subjects. Eleven healthy volunteers participated in this randomized double-blind, placebo controlled cross-over study. The study consisted of three periods of 1 week each, in which the volunteers daily self-administered rectal enemas containing 100, 50 mmol L(-1) butyrate, or placebo (saline) prior to sleeping. A rectal barostat measurement was performed at the start and the end of each test period for the measurement of pain, urge and discomfort. Butyrate treatment resulted in a dose-dependent reduction of pain, urge and discomfort throughout the entire pressure range of the protocol. At a pressure of 4 mmHg, 50 and 100 mmol L(-1) butyrate concentrations resulted in a 23.9% and 42.1% reduction of pain scores, respectively, and the discomfort scores decreased by 44.2% and 69.0% respectively. At a pressure of 67 mmHg, 50 and 100 mmol L(-1) of butyrate decreased the pain scores by 23.8% and 42%, respectively, and discomfort scores 1.9% and 5.2% respectively. Colonic administration of butyrate, at physiologically relevant concentrations, dose-dependently decreases visceral sensitivity in healthy volunteers.
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| 5. |
- Hamer, H. M., et al.
(författare)
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Analyses of human colonic mucus obtained by an in vivo sampling technique
- 2009
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Ingår i: Digestive and Liver Disease. - Amsterdam : W.B. Saunders Co. Ltd.. - 1590-8658 .- 1878-3562. ; 41:8, s. 559-564
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The mucus layer is an important dynamic component of the epithelial barrier. It contains mucin glycoproteins and other compounds secreted by the intestinal epithelium, such as secretory IgA. However, a standardized in vivo sampling technique of mucus in humans is not yet available.AIM: To assess the validity and feasibility of mucin and protein determinations in human colonic mucus collected under physiological conditions.SUBJECTS AND METHODS: Triplicate colonic mucus samples were collected in 11 healthy volunteers using cytology brushes during sigmoidoscopy. As an indication of the quantity of collected mucus, total protein and mucin concentrations were determined by measuring oligosaccharide equivalents and monosaccharides. Also secretory IgA and sialic acid concentrations were determined and proteomic analysis was performed using surface enhanced laser desorption/ionization-time of flight-mass spectrometry.RESULTS: Mean values of secretory IgA and sialic acid corrected for the amount of mucus ranged from 0.16 to 1.81g secretory IgA/mmol oligosaccharide equivalents and from 12.6 to 48.6g sialic acid/mmol oligosaccharide equivalents. Proteomic analysis of mucus is feasible and cluster analysis showed subject specific profiles. CONCLUSION: Using cytology brushes, human colonic mucus can be sampled and under physiological conditions. These samples could give information on the composition and quality of the mucus layer.
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| 6. |
- Hamer, H. M., et al.
(författare)
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Review article : the role of butyrate on colonic function
- 2008
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Ingår i: Alimentary Pharmacology and Therapeutics. - : Wiley. - 0269-2813 .- 1365-2036. ; 27:2, s. 104-119
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: Butyrate, a short-chain fatty acid, is a main end-product of intestinal microbial fermentation of mainly dietary fibre. Butyrate is an important energy source for intestinal epithelial cells and plays a role in the maintenance of colonic homeostasis. AIM: To provide an overview on the present knowledge of the bioactivity of butyrate, emphasizing effects and possible mechanisms of action in relation to human colonic function. METHODS: A PubMed search was performed to select relevant publications using the search terms: 'butyrate, short-chain fatty acid, fibre, colon, inflammation, carcinogenesis, barrier, oxidative stress, permeability and satiety'. RESULTS: Butyrate exerts potent effects on a variety of colonic mucosal functions such as inhibition of inflammation and carcinogenesis, reinforcing various components of the colonic defence barrier and decreasing oxidative stress. In addition, butyrate may promote satiety. Two important mechanisms include the inhibition of nuclear factor kappa B activation and histone deacetylation. However, the observed effects of butyrate largely depend on concentrations and models used and human data are still limited. CONCLUSION: Although most studies point towards beneficial effects of butyrate, more human in vivo studies are needed to contribute to our current understanding of butyrate-mediated effects on colonic function in health and disease.
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