| 1. |
- Nord, Hanna, et al.
(författare)
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Differential regulation of myosin heavy chains defines new muscle domains in zebrafish
- 2014
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Ingår i: Molecular Biology of the Cell. - : American Society for Cell Biology. - 1059-1524 .- 1939-4586. ; 25:8, s. 1384-1395
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Tidskriftsartikel (refereegranskat)abstract
- Numerous muscle lineages are formed during myogenesis within both slow-and fast-specific cell groups. In this study, we show that six fast muscle-specific myosin heavy chain genes have unique expression patterns in the zebrafish embryo. The expression of tail-specific myosin heavy chain (fmyhc2.1) requires wnt signaling and is essential for fast muscle organization within the tail. Retinoic acid treatment results in reduced wnt signaling, which leads to loss of the fmyhc2.1 domain. Retinoic acid treatment also results in a shift of muscle identity within two trunk domains defined by expression of fmyhc1.2 and fmyhc1.3 in favor of the anteriormost myosin isoform, fmyhc1.2. In summary, we identify new muscle domains along the anteroposterior axis in the zebrafish that are defined by individual nonoverlapping, differentially regulated expression of myosin heavy chain isoforms.
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| 2. |
- Baeyens, Luc, et al.
(författare)
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Transient cytokine treatment induces acinar cell reprogramming and regenerates functional beta cell mass in diabetic mice
- 2014
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Ingår i: Nature Biotechnology. - : Springer Science and Business Media LLC. - 1087-0156 .- 1546-1696. ; 32:1, s. 76-83
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Tidskriftsartikel (refereegranskat)abstract
- Reprogramming of pancreatic exocrine cells into cells resembling beta cells may provide a strategy for treating diabetes. Here we show that transient administration of epidermal growth factor and ciliary neurotrophic factor to adult mice with chronic hyperglycemia efficiently stimulates the conversion of terminally differentiated acinar cells to beta-like cells. Newly generated beta-like cells are epigenetically reprogrammed, functional and glucose responsive, and they reinstate normal glycemic control for up to 248 d. The regenerative process depends on Stat3 signaling and requires a threshold number of Neurogenin 3 (Ngn3)-expressing acinar cells. In contrast to previous work demonstrating in vivo conversion of acinar cells to beta-like cells by viral delivery of exogenous transcription factors, our approach achieves acinar-to-beta-cell reprogramming through transient cytokine exposure rather than genetic modification.
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| 3. |
- Cheddad, Abbas, et al.
(författare)
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Improving signal detection in emission optical projection tomography via single source multi-exposure image fusion
- 2013
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 21:14, s. 16584-16604
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a technique to improve structural data obtained from Optical Projection Tomography (OPT) using Image Fusion (IF) and contrast normalization. This enables the visualization of molecular expression patterns in biological specimens with highly variable contrast values. In the approach, termed IF-OPT, different exposures are fused by assigning weighted contrasts to each. When applied to projection images from mouse organs and digital phantoms our results demonstrate the capability of IF-OPT to reveal high and low signal intensity details in challenging specimens. We further provide measurements to highlight the benefits of the new algorithm in comparison to other similar methods.
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| 6. |
- Davies, Wayne I. L., et al.
(författare)
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Distinct opsin 3 (Opn3) expression in the developing nervous system during mammalian embryogenesis
- 2021
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Ingår i: eNeuro. - : Society for Neuroscience. - 2373-2822. ; 8:5
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Tidskriftsartikel (refereegranskat)abstract
- Opsin 3 (Opn3) is highly expressed in the adult brain, however, information for spatial and temporal expression patterns during embryogenesis is significantly lacking. Here, an Opn3-eGFP reporter mouse line was used to monitor cell body expression and axonal projections during embryonic and early postnatal to adult stages. By applying 2D and 3D fluorescence imaging techniques, we have identified the onset of Opn3 expression, which predominantly occurred during embryonic stages, in various structures during brain/head development. In ad-dition, this study defines over twenty Opn3-eGFP-positive neural structures never reported before. Opn3-eGFP was first observed at E9.5 in neural regions, including the ganglia that will ultimately form the trigeminal, facial and vestibulocochlear cranial nerves (CNs). As development proceeds, expanded Opn3-eGFP expression coincided with the formation and maturation of critical components of the central and peripheral nervous systems (CNS, PNS), including various motor-sensory tracts, such as the dorsal column-medial lemniscus (DCML) sensory tract, and olfactory, acoustic, and optic tracts. The widespread, yet distinct, detection of Opn3-eGFP already at early embryonic stages suggests that Opn3 might play important functional roles in the developing brain and spinal cord to regulate multiple motor and sensory circuitry systems, including proprio-ception, nociception, ocular movement, and olfaction, as well as memory, mood, and emotion. This study presents a crucial blueprint from which to investigate autonomic and cognitive opsin-dependent neural development and resultant behaviors under physiological and pathophysiological conditions.
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| 7. |
- Grong, Eivind, et al.
(författare)
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Sleeve gastrectomy, but not duodenojejunostomy, preserves total beta-cell mass in Goto-Kakizaki rats evaluated by three-dimensional optical projection tomography
- 2016
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Ingår i: Surgical Endoscopy. - : Springer Science and Business Media LLC. - 0930-2794 .- 1432-2218. ; 30:2, s. 532-542
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Tidskriftsartikel (refereegranskat)abstract
- Background In type 2 diabetes mellitus, there is a progressive loss of beta-cell mass. Bariatric surgery has in recent investigations showed promising results in terms of diabetes remission, but little is established regarding the effect of surgery on the survival or regeneration of pancreatic beta-cells. In this study, we aim to explore how bariatric surgery with its subsequent hormonal alterations affects the islets of Langerhans.Methods Twenty-four Goto-Kakizaki rats were operated with duodenojejunostomy (DJ), sleeve gastrectomy (SG) or sham operation. From the 38th week after surgery, body weight, fasting blood glucose, glycosylated hemoglobin, mixed meal tolerance with repeated measures of insulin, glucagon-like peptide 1, gastrin and total ghrelin were evaluated. Forty-six weeks after surgery, the animals were euthanized and the total beta-cell mass in all animals was examined by three-dimensional volume quantification by optical projection tomography based on the signal from insulin-specific antibody staining.Results Body weight did not differ between groups (Pg = 0.37). SG showed lower fasting blood glucose compared to DJ and sham (Pg = 0.037); HbA1c levels in SG were lower compared to DJ only (p\0.05). GLP-1 levels were elevated for DJ compared to SG and sham (Pg = 0.001), whereas gastrin levels were higher in SG compared to the two other groups (Pg = 0.002). Beta-cell mass was significantly greater in animals operated with SG compared to both DJ and sham (p = 0.036).Conclusion Sleeve gastrectomy is superior to duodenojejunostomy and sham operation when comparing the preservation of beta-cell mass 46 weeks after surgery in Goto-Kakizaki rats. This could be related to both the increased gastrin levels and the long-term improvement in glycemic parameters observed after this procedure.
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| 8. |
- Grong, E., et al.
(författare)
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The effect of hypergastrinemia following sleeve gastrectomy and pantoprazole on type 2 diabetes mellitus and beta-cell mass in Goto-Kakizaki rats
- 2018
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Ingår i: Journal of Endocrinological Investigation. - : Springer. - 0391-4097 .- 1720-8386. ; 41:6, s. 691-701
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Metabolic surgery alters the secretion of gastrointestinal hormones that influence glycemic control. Elevated gastrin has been suggested to benefit patients with type 2 diabetes and has been reported following sleeve gastrectomy in rats. The present study compares the effect of hypergastrinemia following sleeve gastrectomy with proton-pump inhibitor therapy on glycemic control and beta-cell mass in lean, diabetic animals.Methods: Thirty-three diabetic Goto-Kakizaki rats were randomized into pantoprazole + sham operation (GK-PPI), sleeve gastrectomy (GK-SG) and vehicle + sham operation (GK-V). Body weight, glucose parameters, HbA1c, glucagon-like peptide 1, gastrin, insulin and lipids were evaluated for eighteen postoperative weeks. Total beta-cell mass was quantified by optical projection tomography.Results: After surgery, body weight development was equal among groups (Pg = 0.75). Fasting and stimulated gastrin increased for GK-PPI and GK-SG vs. GK-V (p < 0.05 for all). Fasting blood glucose was decreased for GK-PPI and GK-SG vs. GK-V (p < 0.05 and p = 0.052). HbA1c was lower for GK-SG vs. GK-V at 6 weeks and for GK-PPI vs. GK-V at twelve- and eighteen weeks postoperative (p < 0.05 for all); a borderline difference was observed for GK-SG vs. GK-V at 18 weeks (p = 0.054). Total- and LDL cholesterol was elevated for GK-PPI compared to the other two groups (p < 0.05 for all). Beta-cell mass did not differ among groups (p = 0.35).Conclusions: Hypergastrinemia following sleeve gastrectomy and pantoprazole has a similar, modest effect on glycemic control in Goto-Kakizaki rats but does not enhance beta-cell mass after 18 weeks. Hypergastrinemia in the setting of T2DM might be of clinical relevance.
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| 9. |
- Hahn, Max, et al.
(författare)
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3D imaging of human organs with micrometer resolution - applied to the endocrine pancreas
- 2021
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Ingår i: Communications Biology. - : Springer Nature. - 2399-3642. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- The possibility to quantitatively study specific molecular/cellular features of complete human organs with preserved spatial 3D context would have widespread implications for pre-clinical and clinical medicine. Whereas optical 3D imaging approaches have experienced a formidable revolution, they have remained limited due to current incapacities in obtaining specific labelling within large tissue volumes. We present a simple approach enabling reconstruction of antibody labeled cells within entire human organs with preserved organ context. We demonstrate the utility of the approach by providing volumetric data and 3D distribution of hundreds of thousands of islets of Langerhans within the human pancreas. By assessments of pancreata from non-diabetic and type 2 diabetic individuals, we display previously unrecognized features of the human islet mass distribution and pathology. As such, this method may contribute not only in unraveling new information of the pancreatic anatomy/pathophysiology, but it may be translated to essentially any antibody marker or organ system.
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| 10. |
- Hahn, Max, et al.
(författare)
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Mesoscopic 3D imaging of pancreatic cancer and Langerhans islets based on tissue autofluorescence
- 2020
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Ingår i: Scientific Reports. - : NATURE RESEARCH. - 2045-2322. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- The possibility to assess pancreatic anatomy with microscopic resolution in three dimensions (3D) would significantly add to pathological analyses of disease processes. Pancreatic ductal adenocarcinoma (PDAC) has a bleak prognosis with over 90% of the patients dying within 5 years after diagnosis. Cure can be achieved by surgical resection, but the efficiency remains drearily low. Here we demonstrate a method that without prior immunohistochemical labelling provides insight into the 3D microenvironment and spread of PDAC and premalignant cysts in intact surgical biopsies. The method is based solely on the autofluorescent properties of the investigated tissues using optical projection tomography and/or light-sheet fluorescence microscopy. It does not interfere with subsequent histopathological analysis and may facilitate identification of tumor-free resection margins within hours. We further demonstrate how the developed approach can be used to assess individual volumes and numbers of the islets of Langerhans in unprecedently large biopsies of human pancreatic tissue, thus providing a new means by which remaining islet mass may be assessed in settings of diabetes. Generally, the method may provide a fast approach to provide new anatomical insight into pancreatic pathophysiology.
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