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Träfflista för sökning "WFRF:(Håkansson Joakim 1975) "

Sökning: WFRF:(Håkansson Joakim 1975)

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1.
  • Chinga-Carrasco, Gary, et al. (författare)
  • Characterization and Antibacterial Properties of Autoclaved Carboxylated Wood Nanocellulose
  • 2021
  • Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 22:7, s. 2779-2789
  • Tidskriftsartikel (refereegranskat)abstract
    • Cellulose nanofibrils (CNFs) were obtained by applying a chemical pretreatment consisting of autoclaving the pulp fibers in sodium hydroxide, combined with 2,2,6,6-tetramethylpiperidinyl-1-oxyl-mediated oxidation. Three levels of sodium hypochlorite were applied (2.5, 3.8, and 6.0 mmol/g) to obtain CNF qualities (CNF_2.5, CNF_3.8, and CNF_6.0) with varying content of carboxyl groups, that is, 1036, 1285, and 1593 mu mol/g cellulose. The cytotoxicity and skin irritation potential (indirect tests) of the CNFs were determined according to standardized in vitro testing for medical devices. We here demonstrate that autoclaving (121 degrees C, 20 min), which was used to sterilize the gels, caused a modification of the CNF characteristics. This was confirmed by a reduction in the viscosity of the gels, a morphological change of the nanofibrils, by an increase of the ultraviolet-visible absorbance maxima at 250 nm, reduction of the absolute zeta potential, and by an increase in aldehyde content and reducing sugars after autoclaving. Fourier-transform infrared spectroscopy and wide-angle X-ray scattering complemented an extensive characterization of the CNF gels, before and after autoclaving. The antibacterial properties of autoclaved carboxylated CNFs were demonstrated in vitro (bacterial survival and swimming assays) on Pseudomonas aeruginosa and Staphylococcus aureus. Importantly, a mouse in vivo surgical-site infection model on S. aureus revealed that CNF_3.8 showed pronounced antibacterial effect and performed as good as the antiseptic Prontosan wound gel.
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2.
  • Holmbäck, Jan, et al. (författare)
  • Preclinical development of sodium fusidate antibiotic cutaneous spray based on water-free lipid formulation system
  • 2022
  • Ingår i: European Journal of Pharmaceutical Sciences. - : Elsevier BV. - 0928-0987 .- 1879-0720. ; 176
  • Tidskriftsartikel (refereegranskat)abstract
    • Topical antibiotics are a key component in the management of mild to moderate skin and soft tissue infections. There are, however, concerns about the emerging bacterial resistance against topical antibacterial agents such as fusidic acid, due to the prolonged treatment period of its marketed dosage forms. Improving the efficacy of topical formulations could potentially shorten the treatment period and avoid the resistance growth. To provide a more effective drug delivery, a water-free lipid-based formulation system (AKVANO (R)) which can be applied by spraying, has been developed. In the current paper, different formulations containing sodium fusidate were evaluated for their in vitro skin permeability using artificial skin mimicking membranes and antibacterial properties using ex vivo and in vivo skin wound infection models. The novel formulations containing sodium fusidate showed a much higher skin permeation (up to 60% of nominal amount) than the commercially available Fucidin (R) cream (3%). These formulations also gave a significantly stronger antibacterial effect than Fucidin cream showing a clear dose-response relationship for the sodium fusidate content. A spray product based on the described formulation technology would therefore require a shorter treatment time and thereby lower the risk for the development of bacterial resistance. Spray administration of these formulations provides an even layer on the skin surface from which the solvent quickly evaporates and thereby facilitates a non-touch application where no rubbing is required.
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3.
  • Landberg, Göran, 1963, et al. (författare)
  • Characterization of cell-free breast cancer patient-derived scaffolds using liquid chromatography-mass spectrometry/mass spectrometry data and RNA sequencing data
  • 2020
  • Ingår i: Data in Brief. - : Elsevier BV. - 2352-3409. ; 31
  • Tidskriftsartikel (refereegranskat)abstract
    • Patient-derived scaffolds (PDSs) generated from primary breast cancer tumors can be used to model the tumor microenvironment in vitro . Patient-derived scaffolds are generated by repeated detergent washing, removing all cells. Here, we analyzed the protein composition of 15 decellularized PDSs using liquid chromatography-mass spectrometry/mass spectrometry. One hundred forty-three proteins were detected and their relative abundance was calculated using a reference sample generated from all PDSs. We performed heatmap analysis of all the detected proteins to display their expression patterns across different PDSs together with pathway enrichment analysis to reveal which processes that were connected to PDS protein composition. This protein dataset together with clinical information is useful to investigators studying the microenvironment of breast cancers. Further, after repopulating PDSs with either MCF7 or MDA-MB-231 cells, we quantified their gene expression profiles using RNA sequencing. These data were also compared to cells cultured in conventional 2D conditions, as well as to cells cultured as xenografts in immune-deficient mice. We investigated the overlap of genes regulated between these different culture conditions and performed pathway enrichment analysis of genes regulated by both PDS and xenograft cultures compared to 2D in both cell lines to describe common processes associated with both culture conditions. Apart from our described analyses of these systems, these data are useful when comparing different experimental model systems. Downstream data analyses and interpretations can be found in the research article "Patient-derived scaffolds uncover breast cancer promoting properties of the microenvironment" [1] . (C) 2020 The Authors. Published by Elsevier Inc.
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4.
  • Garre, Elena, 1978, et al. (författare)
  • Breast Cancer Patient-Derived Scaffolds Can Expose Unique Individual Cancer Progressing Properties of the Cancer Microenvironment Associated with Clinical Characteristics
  • 2022
  • Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 14:9
  • Tidskriftsartikel (refereegranskat)abstract
    • Simple Summary Despite huge progress in cancer diagnostics and medicine we still lack optimal cancer treatments for patients with aggressive diseases. This problem can be influenced by the biological heterogeneity of cancer cells as well as poorly understood cancer promoting effects of the cancer microenvironment being an important part of the cancer niche. In this study we have specifically monitored the activity of the cancer microenvironment in breast cancer patients using cell-free scaffolds repopulated with reporter cancer cells sensing the activity of the patient environment. The data show that scaffold induced changes in epithelial-mesenchymal transition and pluripotency markers were linked to clinical and prognostic properties of the original cancer and the information was even more precise when matching estrogen receptor status in our system. The findings highlight that patient-derived scaffolds uncover important information about varying malignant promoting properties in the cancer niche and can be used as a complementary diagnostic tool. Breast cancer is a heterogeneous disease in terms of cellular and structural composition, and besides acquired aggressive properties in the cancer cell population, the surrounding tumor microenvironment can affect disease progression and clinical behaviours. To specifically decode the clinical relevance of the cancer promoting effects of individual tumor microenvironments, we performed a comprehensive test of 110 breast cancer samples using a recently established in vivo-like 3D cell culture platform based on patient-derived scaffolds (PDSs). Cell-free PDSs were recellularized with three breast cancer cell lines and adaptation to the different patient-based microenvironments was monitored by quantitative PCR. Substantial variability in gene expression between individual PDS cultures from different patients was observed, as well as between different cell lines. Interestingly, specific gene expression changes in the PDS cultures were significantly linked to prognostic features and clinical information from the original cancer. This link was even more pronounced when ER alpha-status of cell lines and PDSs matched. The results support that PDSs cultures, including a cancer cell line of relevant origin, can monitor the activity of the tumor microenvironment and reveal unique information about the malignancy-inducing properties of the individual cancer niche and serve as a future complementary diagnostic tool for breast cancer.
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5.
  • Håkansson, Joakim, 1975, et al. (författare)
  • N-CAM exhibits a regulatory function in pathological angiogenesis in oxygen induced retinopathy.
  • 2011
  • Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 6:10
  • Tidskriftsartikel (refereegranskat)abstract
    • Diabetic retinopathy and retinopathy of prematurity are diseases caused by pathological angiogenesis in the retina as a consequence of local hypoxia. The underlying mechanism for epiretinal neovascularization (tuft formation), which contributes to blindness, has yet to be identified. Neural cell adhesion molecule (N-CAM) is expressed by Müller cells and astrocytes, which are in close contact with the retinal vasculature, during normal developmental angiogenesis.
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6.
  • Håkansson, Joakim, 1975, et al. (författare)
  • Neural cell adhesion molecule-deficient beta-cell tumorigenesis results in diminished extracellular matrix molecule expression and tumour cell-matrix adhesion
  • 2005
  • Ingår i: Tumour Biology. - : Springer Science and Business Media LLC. - 1010-4283 .- 1423-0380. ; 26:2, s. 103-112
  • Tidskriftsartikel (refereegranskat)abstract
    • To understand by which mechanism neural cell adhesion molecule (N-CAM) limits beta tumour cell disaggregation and dissemination, we searched for potential downstream genes of N-CAM during beta tumour cell progression by gene expression profiling. Here, we show that N-CAM-deficient beta-cell tumorigenesis is associated with changes in the expression of genes involved in cell-matrix adhesion and cytoskeletal dynamics, biological processes known to affect the invasive and metastatic behaviour of tumour cells. The extracellular matrix (ECM) molecules emerged as the primary target, i.e. N-CAM deficiency resulted in down-regulated mRNA expression of a broad range of ECM molecules. Consistent with this result, deficient deposition of major ECM stromal components, such as fibronectin, laminin 1 and collagen IV, was observed. Moreover, N-CAM-deficient tumour cells displayed defective matrix adhesion. These results offer a potential mechanism for tumour cell disaggregation during N-CAM-deficient beta tumour cell progression. Prospective consequences of these findings for the role of N-CAM in beta tumour cell dissemination are discussed.
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7.
  • Landberg, Göran, et al. (författare)
  • Patient-derived scaffolds uncover breast cancer promoting properties of the microenvironment
  • 2020
  • Ingår i: Biomaterials. - : Elsevier Ltd. - 0142-9612 .- 1878-5905. ; 235
  • Tidskriftsartikel (refereegranskat)abstract
    • Tumor cells interact with the microenvironment that specifically supports and promotes tumor development. Key components in the tumor environment have been linked to various aggressive cancer features and can further influence the presence of subpopulations of cancer cells with specific functions, including cancer stem cells and migratory cells. To model and further understand the influence of specific microenvironments we have developed an experimental platform using cell-free patient-derived scaffolds (PDSs) from primary breast cancers infiltrated with standardized breast cancer cell lines. This PDS culture system induced a series of orchestrated changes in differentiation, epithelial-mesenchymal transition, stemness and proliferation of the cancer cell population, where an increased cancer stem cell pool was confirmed using functional assays. Furthermore, global gene expression profiling showed that PDS cultures were similar to xenograft cultures. Mass spectrometry analyses of cell-free PDSs identified subgroups based on their protein composition that were linked to clinical properties, including tumor grade. Finally, we observed that an induction of epithelial-mesenchymal transition-related genes in cancer cells growing on the PDSs were significantly associated with clinical disease recurrences in breast cancer patients. Patient-derived scaffolds thus mimics in vivo-like growth conditions and uncovers unique information about the malignancy-inducing properties of tumor microenvironment. © 2019 The Authors
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8.
  • Leiva, Maria Carmen, et al. (författare)
  • Breast cancer patient-derived scaffolds as a tool to monitor chemotherapy responses in human tumor microenvironments
  • 2021
  • Ingår i: Journal of Cellular Physiology. - : Wiley. - 0021-9541 .- 1097-4652. ; 236:6, s. 4709-4724
  • Tidskriftsartikel (refereegranskat)abstract
    • Breast cancer is a heterogeneous disease where the tumor microenvironment, including extracellular components, plays a crucial role in tumor progression, potentially modulating treatment response. Different approaches have been used to develop three-dimensional models able to recapitulate the complexity of the extracellular matrix. Here, we use cell-free patient-derived scaffolds (PDSs) generated from breast cancer samples that were recellularized with cancer cell lines as an in vivo-like culture system for drug testing. We show that PDS cultured MCF7 cancer cells increased their resistance against the front-line chemotherapy drugs 5-fluorouracil, doxorubicin and paclitaxel in comparison to traditional two-dimensional cell cultures. The gene expression of the environmentally adapted cancer cells was modulated in different ways depending on the drug and the concentration used. High doses of doxorubicin reduced cancer stem cell features, whereas 5-fluorouracil increased stemness and decreased the proliferative phenotype. By using PDSs repopulated with other breast cancer cell lines, T-47D and MDA-MB-231, we observed both general and cell line specific drug responses. In summary, PDSs can be used to examine the extracellular matrix influence on cancer drug responses and for testing novel compounds in in vivo-like microenvironments.
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9.
  • Parkinson, Gabrielle T., et al. (författare)
  • Patient-derived scaffolds as a model of colorectal cancer
  • 2021
  • Ingår i: Cancer Medicine. - : Wiley. - 2045-7634. ; 10:3, s. 867-882
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Colorectal cancer is the second most common cause of cancer-related death worldwide and standardized therapies often fail to treat the more aggressive and progressive types of colorectal cancer. Tumor cell heterogeneity and influence from the surrounding tumor microenvironment (TME) contribute to the complexity of the disease and large variability in clinical outcomes. Methods To model the heterogeneous nature of colorectal cancer, we used patient-derived scaffolds (PDS), which were obtained via decellularization of surgically resected tumor material, as a growth substrate for standardized cell lines. Results After confirmation of native cell absence and validation of the structural and compositional integrity of the matrix, 89 colorectal PDS were repopulated with colon cancer cell line HT29. After 3 weeks of PDS culture, HT29 cells varied their gene and protein expression profiles considerably compared to 2D-grown HT29 cells. Markers associated with proliferation were consistently decreased, while markers associated with pluripotency were increased in PDS-grown cells compared to their 2D counterparts. When comparing the PDS-induced changes in HT29 cells with clinically relevant tumor information from individual patients, we observed significant associations between stemness/pluripotency markers and tumor location, and between epithelial-to-mesenchymal transition (EMT) markers and cancer mortality. Kaplan-Meier analysis revealed that low PDS-induced EMT correlated with worse cancer-specific survival. Conclusions The colorectal PDS model can be used as a simplified personalized tool that can potentially reveal important diagnostic and pathophysiological information related to the TME.
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10.
  • Pasquier, Eva, et al. (författare)
  • Polysaccharides and Structural Proteins as Components in Three-Dimensional Scaffolds for Breast Cancer Tissue Models: A Review
  • 2023
  • Ingår i: Bioengineering. - : MDPI. - 2306-5354. ; 10:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Breast cancer is the most common cancer among women, and even though treatments are available, efficiency varies with the patients. In vitro 2D models are commonly used to develop new treatments. However, 2D models overestimate drug efficiency, which increases the failure rate in later phase III clinical trials. New model systems that allow extensive and efficient drug screening are thus required. Three-dimensional printed hydrogels containing active components for cancer cell growth are interesting candidates for the preparation of next generation cancer cell models. Macromolecules, obtained from marine- and land-based resources, can form biopolymers (polysaccharides such as alginate, chitosan, hyaluronic acid, and cellulose) and bioactive components (structural proteins such as collagen, gelatin, and silk fibroin) in hydrogels with adequate physical properties in terms of porosity, rheology, and mechanical strength. Hence, in this study attention is given to biofabrication methods and to the modification with biological macromolecules to become bioactive and, thus, optimize 3D printed structures that better mimic the cancer cell microenvironment. Ink formulations combining polysaccharides for tuning the mechanical properties and bioactive polymers for controlling cell adhesion is key to optimizing the growth of the cancer cells.
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11.
  • Rosendahl, Jennifer, et al. (författare)
  • 3D printed nanocellulose scaffolds as a cancer cell culture model system
  • 2021
  • Ingår i: Bioengineering. - : MDPI AG. - 2306-5354. ; 8:7
  • Tidskriftsartikel (refereegranskat)abstract
    • Current conventional cancer drug screening models based on two-dimensional (2D) cell culture have several flaws and there is a large need of more in vivo mimicking preclinical drug screening platforms. The microenvironment is crucial for the cells to adapt relevant in vivo characteristics and here we introduce a new cell culture system based on three-dimensional (3D) printed scaffolds using cellulose nanofibrils (CNF) pre-treated with 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO) as the structural material component. Breast cancer cell lines, MCF7 and MDA-MB-231, were cultured in 3D TEMPO-CNF scaffolds and were shown by scanning electron microscopy (SEM) and histochemistry to grow in multiple layers as a heterogenous cell population with different morphologies, contrasting 2D cultured mono-layered cells with a morphologically homogenous cell population. Gene expression analysis demonstrated that 3D TEMPO-CNF scaffolds induced elevation of the stemness marker CD44 and the migration markers VIM and SNAI1 in MCF7 cells relative to 2D control. T47D cells confirmed the increased level of the stemness marker CD44 and migration marker VIM which was further supported by increased capacity of holoclone formation for 3D cultured cells. Therefore, TEMPO-CNF was shown to represent a promising material for 3D cell culture model systems for cancer cell applications such as drug screening. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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12.
  • Sidstedt, Maja, et al. (författare)
  • Ultrasensitive sequencing of STR markers utilizing unique molecular identifiers and the SiMSen-Seq method
  • 2024
  • Ingår i: Forensic Science International: Genetics. - : Elsevier Ireland Ltd. - 1872-4973 .- 1878-0326. ; 71
  • Tidskriftsartikel (refereegranskat)abstract
    • Massively parallel sequencing (MPS) is increasingly applied in forensic short tandem repeat (STR) analysis. The presence of stutter artefacts and other PCR or sequencing errors in the MPS-STR data partly limits the detection of low DNA amounts, e.g., in complex mixtures. Unique molecular identifiers (UMIs) have been applied in several scientific fields to reduce noise in sequencing. UMIs consist of a stretch of random nucleotides, a unique barcode for each starting DNA molecule, that is incorporated in the DNA template using either ligation or PCR. The barcode is used to generate consensus reads, thus removing errors. The SiMSen-Seq (Simple, multiplexed, PCR-based barcoding of DNA for sensitive mutation detection using sequencing) method relies on PCR-based introduction of UMIs and includes a sophisticated hairpin design to reduce unspecific primer binding as well as PCR protocol adjustments to further optimize the reaction. In this study, SiMSen-Seq is applied to develop a proof-of-concept seven STR multiplex for MPS library preparation and an associated bioinformatics pipeline. Additionally, machine learning (ML) models were evaluated to further improve UMI allele calling. Overall, the seven STR multiplex resulted in complete detection and concordant alleles for 47 single-source samples at 1 ng input DNA as well as for low-template samples at 62.5 pg input DNA. For twelve challenging mixtures with minor contributions of 10 pg to 150 pg and ratios of 1–15% relative to the major donor, 99.2% of the expected alleles were detected by applying the UMIs in combination with an ML filter. The main impact of UMIs was a substantially lowered number of artefacts as well as reduced stutter ratios, which were generally below 5% of the parental allele. In conclusion, UMI-based STR sequencing opens new means for improved analysis of challenging crime scene samples including complex mixtures.
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13.
  • Ståhlberg, Anders, 1975, et al. (författare)
  • Properties of the reverse transcription reaction in mRNA quantification.
  • 2004
  • Ingår i: Clinical chemistry. - : Oxford University Press (OUP). - 0009-9147 .- 1530-8561. ; 50:3, s. 509-15
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: In most measurements of gene expression, mRNA is first reverse-transcribed into cDNA. We studied the reverse transcription reaction and its consequences for quantitative measurements of gene expression. METHODS: We used SYBR green I-based quantitative real-time PCR (QPCR) to measure the properties of reverse transcription reaction for the beta-tubulin, glyceraldehyde-3-phosphate dehydrogenase, Glut2, CaV1D, and insulin II genes, using random hexamers, oligo(dT), and gene-specific reverse transcription primers. RESULTS: Experimental variation in reverse transcription-QPCR (RT-QPCR) was mainly attributable to the reverse transcription step. Reverse transcription efficiency depended on priming strategy, and the dependence was different for the five genes studied. Reverse transcription yields also depended on total RNA concentration. CONCLUSIONS: RT-QPCR gene expression measurements are comparable only when the same priming strategy and reaction conditions are used in all experiments and the samples contain the same total amount of RNA. Experimental accuracy is improved by running samples in (at least) duplicate starting with the reverse transcription reaction.
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14.
  • Svanström, Andreas, et al. (författare)
  • Optimized alginate-based 3D printed scaffolds as a model of patient derived breast cancer microenvironments in drug discovery
  • 2021
  • Ingår i: Biomedical Materials (Bristol). - : IOP Publishing Ltd. - 1748-6041 .- 1748-605X. ; 16:4
  • Tidskriftsartikel (refereegranskat)abstract
    • The cancer microenvironment influences tumor progression and metastasis and is pivotal to consider when designing in vivo-like cancer models. Current preclinical testing platforms for cancer drug development are mainly limited to 2D cell culture systems that poorly mimic physiological environments and traditional, low throughput animal models. The aim of this work was to produce a tunable testing platform based on 3D printed scaffolds (3DPS) with a simple geometry that, by extracellular components and response of breast cancer reporter cells, mimics patient-derived scaffolds (PDS) of breast cancer. Here, the biocompatible polysaccharide alginate was used as base material to generate scaffolds consisting of a 3D grid containing periostin and hydroxyapatite. Breast cancer cell lines (MCF7 and MDA-MB-231) produced similar phenotypes and gene expression levels of cancer stem cell, epithelial-mesenchymal transition, differentiation and proliferation markers when cultured on 3DPS and PDS, contrasting conventional 2D cultures. Importantly, cells cultured on 3DPS and PDS showed scaffold-specific responses to cytotoxic drugs (doxorubicin and 5-fluorouracil) that were different from 2D cultured cells. In conclusion, the data presented support the use of a tunable alginate-based 3DPS as a tumor model in breast cancer drug discovery. © 2021 The Author(s). Published by IOP Publishing Ltd.
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15.
  • Xian, Xiaojie, 1971, et al. (författare)
  • Pericytes limit tumor cell metastasis.
  • 2006
  • Ingår i: The Journal of clinical investigation. - 0021-9738. ; 116:3, s. 642-51
  • Tidskriftsartikel (refereegranskat)abstract
    • Previously we observed that neural cell adhesion molecule (NCAM) deficiency in beta tumor cells facilitates metastasis into distant organs and local lymph nodes. Here, we show that NCAM-deficient beta cell tumors grew leaky blood vessels with perturbed pericyte-endothelial cell-cell interactions and deficient perivascular deposition of ECM components. Conversely, tumor cell expression of NCAM in a fibrosarcoma model (T241) improved pericyte recruitment and increased perivascular deposition of ECM molecules. Together, these findings suggest that NCAM may limit tumor cell metastasis by stabilizing the microvessel wall. To directly address whether pericyte dysfunction increases the metastatic potential of solid tumors, we studied beta cell tumorigenesis in primary pericyte-deficient Pdgfb(ret/ret) mice. This resulted in beta tumor cell metastases in distant organs and local lymph nodes, demonstrating a role for pericytes in limiting tumor cell metastasis. These data support a new model for how tumor cells trigger metastasis by perturbing pericyte-endothelial cell-cell interactions.
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16.
  • Hansson, Mattias, et al. (författare)
  • Artifactual insulin release from differentiated embryonic stem cells.
  • 2004
  • Ingår i: Diabetes. - 0012-1797. ; 53:10, s. 2603-9
  • Tidskriftsartikel (refereegranskat)abstract
    • Several recent reports claim the generation of insulin-producing cells from embryonic stem cells via the differentiation of progenitors that express nestin. Here, we investigate further the properties of these insulin-containing cells. We find that although differentiated cells contain immunoreactive insulin, they do not contain proinsulin-derived C-peptide. Furthermore, we find variable insulin release from these cells upon glucose addition, but C-peptide release is never detected. In addition, many of the insulin-immunoreactive cells are undergoing apoptosis or necrosis. We further show that cells cultured in the presence of a phosphoinositide 3-kinase inhibitor, which previously was reported to facilitate the differentiation of insulin(+) cells, are not C-peptide immunoreactive but take up fluorescein isothiocyanate-labeled insulin from the culture medium. Together, these data suggest that nestin(+) progenitor cells give rise to a population of cells that contain insulin, not as a result of biosynthesis but from the uptake of exogenous insulin. We conclude that C-peptide biosynthesis and secretion should be demonstrated to claim insulin production from embryonic stem cell progeny.
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17.
  • Hui, I. S. B., et al. (författare)
  • Biocomposites containing poly(lactic acid) and chitosan for 3D printing - Assessment of mechanical, antibacterial and in vitro biodegradability properties
  • 2023
  • Ingår i: Journal of the Mechanical Behavior of Biomedical Materials. - : Elsevier Ltd. - 1751-6161 .- 1878-0180. ; 147
  • Tidskriftsartikel (refereegranskat)abstract
    • New bone repair materials are needed for treatment of trauma-and disease-related skeletal defects as they still represent a major challenge in clinical practice. Additionally, new strategies are required to combat orthopedic device-related infections (ODRI), given the rising incidence of total joint replacement and fracture fixation surgeries in increasingly elderly populations. Recently, the convergence of additive manufacturing (AM) and bone tissue engineering (BTE) has facilitated the development of bone healthcare to achieve personalized three-dimensional (3D) scaffolds. This study focused on the development of a 3D printable bone repair material, based on the biopolymers poly(lactic acid) (PLA) and chitosan. Two different types of PLA and chitosan differing in their molecular weight (MW) were explored. The novel feature of this research was the successful 3D printing using biocomposite filaments composed of PLA and 10 wt% chitosan, with clear chitosan entrapment within the PLA matrix confirmed by Scanning Electron Microscopy (SEM) images. Tensile testing of injection molded samples indicated an increase in stiffness, compared to pure PLA scaffolds, suggesting potential for improved load-bearing characteristics in bone scaffolds. However, the potential benefit of chitosan on the biocomposite stiffness could not be reproduced in compression testing of 3D printed cylinders. The antibacterial assays confirmed antibacterial activity of chitosan when dissolved in acetic acid. The study also verified the biodegradability of the scaffolds, with a process producing an acidic environment that could potentially be neutralized by chitosan. In conclusion, the study indicated the feasibility of the proposed PLA/chitosan biocomposite for 3D printing, demonstrating adequate mechanical strength, antibacterial properties and biodegradability, which could serve as a new material for bone repair.
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18.
  • Håkansson, Joakim, 1975, et al. (författare)
  • Adipocyte mitochondrial genes and the forkhead factor FOXC2 are decreased in type 2 diabetes patients and normalized in response to rosiglitazone.
  • 2011
  • Ingår i: Diabetology & metabolic syndrome. - : Springer Science and Business Media LLC. - 1758-5996. ; 3:1
  • Tidskriftsartikel (refereegranskat)abstract
    • ABSTRACT: BACKGROUND: FOXC2 has lately been implicated in diabetes and obesity as well as mitochondrial function and biogenesis and also as a regulator of mtTFA/Tfam. In this study, the expression of FOXC2 and selected genes involved in mitochondrial function and biogenesis in healthy subjects and in a matched cohort with type 2 diabetes patients before and after treatment with rosiglitazone was determined. Quantitative real time PCR was used to analyze both RNA and DNA from biopsies from subcutaneous adipose tissue. METHODS: Blood samples and subcutaneous abdominal fat biopsies were collected from 12 T2D patients, of which 11 concluded the study, pre-treatment and 90 days after initiation of rosiglitazone treatment, and from 19 healthy control subjects on the first and only visit from healthy subjects. Clinical parameters were measured on the blood samples. RNA and DNA were prepared from the fat biopsies and gene expression was measured with real time PCR. RESULTS: The expression level of genes in the mitochondrial respiratory complexes I - IV were significantly downregulated in the diabetic patients and restored in response to rosiglitazone treatment. Rosiglitazone treatment also increased the relative number of mitochondria in diabetic patients compared with controls. Furthermore, the transcription factors FOXC2 and mtTFA/Tfam displayed a response pattern identical to the mitochondrial genes. CONCLUSIONS: FOXC2, mtTFA/Tfam and subunits of the respiratory complexes I - IV show equivalent regulation in gene expression levels in response to TZD treatment. This, together with the knowledge that FOXC2 has a regulatory function of mtTFA/Tfam and mitochondrial biogenesis, suggests that FOXC2 has a possible functional role in the TZD activated mitochondrial response.
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19.
  • Håkansson, Joakim, 1975, et al. (författare)
  • Changes in ion-channels in the dorsal root ganglion after exposure to autologous nucleus pulposus and TNF. A rat experimental study
  • 2024
  • Ingår i: Journal of Orthopaedics. - : Reed Elsevier India Pvt. Ltd.. - 0972-978X .- 2589-9082. ; 47, s. 23-27
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: It is known that contact of nucleus pulposus with the dorsal root ganglion may induce changes in nerve conduction and pain behavior. It has also been suggested that the behavioristic changes are caused by changes in voltage-gated ion channels, which in turn have been upregulated by TNF. Such upregulations have previously been shown for NaV 1.8 and NaV 1.9. In this investigation, we expanded the number of studied ion channels after the application of nucleus pulposus or TNF. Methods: Following removal of the left L4-5 fact joint, a disc puncture was performed and the dorsal root ganglion was exposed to nucleus pulposus (n = 5) and TNF (n = 5). Operated rats without disc puncture served as sham (n = 5) and 5 non-operated (naïve) rats were included. After 24 h, the DRGs were harvested and analyzed by quantitative PCR on validated pre-spotted primer plates displaying genes for 90 voltage-gated ion channels. Results: It was evident that the changes in operated animals were separate from the naïve rats. It was also apparent that gene expression changes in rats with nucleus pulposus or TNF application showed similar trends and were also separated from sham-operated animals. Conclusion: The application of nucleus pulposus and TNF onto the DRG in rats induces comparable changes in gene expression of several ion channels. Since the changes induced by TNF and NP are similar, one might also suspect that TNF mediates the NP-induced changes. However, such a mechanism needs further investigation.
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20.
  • Håkansson, Joakim, 1975, et al. (författare)
  • Effect of lactoferrin peptide (PXL01) on rabbit digital mobility after flexor tendon repair
  • 2012
  • Ingår i: Journal of Hand Surgery-American Volume. - : Elsevier BV. - 0363-5023 .- 1531-6564. ; 37:12, s. 2519-25
  • Tidskriftsartikel (refereegranskat)abstract
    • Abstract PURPOSE: Restoration of digital function after flexor tendon injuries remains a clinical challenge. Complications such as adhesion formation and tendon rupture can lead to limited hand function. The aim of this study was to compare the effects of the lactoferrin-derived peptide, PXL01, formulated in sodium hyaluronate (SH), with SH alone on joint mobility as an indirect measure of postsurgical adhesion prevention and healing strength of the tendon and to elucidate the most optimal concentration of PXL01. METHODS: Using a rabbit flexor tendon repair model, in which the deep flexor tendon was fully transected and repaired, PXL01 in SH or SH alone was administered between the repaired tendon and the tendon sheath before closure of the surgical wound. Three concentrations of PXL01 in SH (5, 20, or 40 mg/mL) were compared to determine the lowest effective concentration. The repaired tendons were evaluated 7 weeks after surgery by measuring the proximal interphalangeal joint mobility by full range of flexion assessment and the tendon repair strength. RESULTS: Treatment with PXL01 formulated in SH resulted in improved mobility of the proximal interphalangeal joint with an average of 10°, corresponding to improvement of approximately 25% to 60% of the flexion of nonoperated toes at the different measuring points compared with SH alone. The difference was statistically significant in 5 out of 6 measuring points (0.5, 1, 2, 3, and 4 N; P < .05). The dose-response study indicated that the lowest effective concentration of PXL01 was 20 mg/mL. There was no difference in healing strength of the tendon between the groups as assessed by load-to-failure breaking strength. CONCLUSIONS: PXL01 in SH significantly improved the mobility compared with the carrier SH alone, without any negative effect on healing strength, and PXL01 at 20 mg/mL was the lowest effective concentration. CLINICAL RELEVANCE: The result provides a valuable basis for a clinical trial to assess efficacy and safety of PXL01 in clinical hand surgery. Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.
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21.
  • Håkansson, Joakim, 1975, et al. (författare)
  • In vitro and in vivo antibacterial properties of peptide AMC-109 impregnated wound dressings and gels
  • 2021
  • Ingår i: Journal of Antibiotics. - : Springer Science and Business Media LLC. - 0021-8820 .- 1881-1469. ; 74, s. 337-345
  • Tidskriftsartikel (refereegranskat)abstract
    • Synthetic mimics of antimicrobial peptides (AMPs) is a promising class of molecules for a variety of antimicrobial applications. Several hurdles must be passed before effective systemic infection therapies with AMPs can be achieved, but the path to effective topical treatment of skin, nail, and soft tissue infections appears less challenging to navigate. Skin and soft tissue infection is closely coupled to the emergence of antibiotic resistance and represents a major burden to the healthcare system. The present study evaluates the promising synthetic cationic AMP mimic, AMC-109, for treatment of skin infections in vivo. The compound is evaluated both in impregnated cotton wound dressings and in a gel formulation against skin infections caused by Staphylococcus aureus and methicillin resistant S. aureus. Both the ability to prevent colonization and formation of an infection, as well as eradicate an ongoing infection in vivo with a high bacterial load, were evaluated. The present work demonstrates that AMC-109 displays a significantly higher antibacterial activity with up to a seven-log reduction in bacterial loads compared to current clinical standard therapy; Altargo cream (1% retapamulin) and Fucidin cream (2% fusidic acid) in the in vivo wound models. It is thus concluded that AMC-109 represents a promising entry in the development of new and effective remedies for various skin infections.
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22.
  • Håkansson, Joakim, 1975, et al. (författare)
  • Individualized tissue-engineered veins as vascular grafts: A proof of concept study in pig
  • 2021
  • Ingår i: Journal of Tissue Engineering and Regenerative Medicine. - : Hindawi Limited. - 1932-6254 .- 1932-7005. ; 15:10, s. 818-830
  • Tidskriftsartikel (refereegranskat)abstract
    • Personalized tissue engineered vascular grafts are a promising advanced therapy medicinal product alternative to autologous or synthetic vascular grafts utilized in blood vessel bypass or replacement surgery. We hypothesized that an individualized tissue engineered vein (P-TEV) would make the body recognize the transplanted blood vessel as autologous, decrease the risk of rejection and thereby avoid lifelong treatment with immune suppressant medication as is standard with allogenic organ transplantation. To individualize blood vessels, we decellularized vena cava from six deceased donor pigs and tested them for cellular removal and histological integrity. A solution with peripheral blood from the recipient pigs was used for individualized reconditioning in a perfusion bioreactor for seven days prior to transplantation. To evaluate safety and functionality of the individualized vascular graft in vivo, we transplanted reconditioned porcine vena cava into six pigs and analyzed histology and patency of the graft at different time points, with three pigs at the final endpoint 4-5 weeks after surgery. Our results showed that the P-TEV was fully patent in all animals, did not induce any occlusion or stenosis formation and we did not find any signs of rejection. The P-TEV showed rapid recellularization in vivo with the luminal surface covered with endothelial cells. In summary, the results indicate that P-TEV is functional and have potential for use as clinical transplant grafts.
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23.
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24.
  • Olmarker, Kjell, 1958, et al. (författare)
  • Model for assessment of mobility of toes and healing of tendons in rabbits.
  • 2010
  • Ingår i: Journal of plastic surgery and hand surgery. - 2000-6764 .- 2000-656X. ; 44:6, s. 266-71
  • Forskningsöversikt (refereegranskat)abstract
    • Repair of a transected flexor tendon will, despite careful technique and early rehabilitation, usually result in a restricted range of movement. This is mainly because adhesions form between the tendon and the surrounding structures. Our aim was to establish an experimental model in rabbits for future studies on new techniques to reduce the formation of adhesions after zone II repair of flexor tendons. In rabbits' hind paws the metatarsal bones II, IV, and V were removed and the flexor tendon was freed to the metatarsophalangeal (MTP) joint. The digits were secured in a specifically-designed biomechanical testing device comprising a servo-hydraulic actuator that was designed to apply controlled force or displacement. The tests were videotaped with a digital force-monitor behind the tested digit. Paper printouts from the recordings were obtained for 0, 0.5, 1, 2, 3, 4, and 5 Newton (N) and metatarsophalangeal, proximal interphalangeal, and distal interphalangeal, angles and distances between metatarsophalangeal joints and claws were measured. The tensile strength of the tendon was evaluated by a load-to-failure test. The continuous data obtained from the experiments were used to calculate functional stiffness at the selected forces. The model allows for unique continuous recordings of mobility of toes, thereby indirectly quantifying the presence of adhesions and the assessment of tensile strength. The data are reproducible, and there is little variation between the digits tested. The model is primarily intended to compare data among treated and non-treated digits of methods to limit the formation of adhesions after tendons have been repaired.
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25.
  • Rosendahl, Jennifer, et al. (författare)
  • Gene-Expression Analysis of Human Fibroblasts Affected by 3D-Printed Carboxylated Nanocellulose Constructs
  • 2023
  • Ingår i: Bioengineering. - : MDPI AG. - 2306-5354. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Three-dimensional (3D) printing has emerged as a highly valuable tool to manufacture porous constructs. This has major advantages in, for example, tissue engineering, in which 3D scaffolds provide a microenvironment with adequate porosity for cell growth and migration as a simulation of tissue regeneration. In this study, we assessed the suitability of three cellulose nanofibrils (CNF) that were obtained through 2,2,6,6-tetramethylpyperidine-1-oxyl (TEMPO)-mediated oxidation. The CNFs were obtained by applying three levels of carboxylation, i.e., 2.5, 3.8, and 6.0 mmol sodium hypochlorite (NaClO) per gram of cellulose. The CNFs exhibited different nanofibrillation levels, affecting the corresponding viscosity and 3D printability of the CNF gels (0.6 wt%). The scaffolds were manufactured by micro-extrusion and the nanomechanical properties were assessed with nanoindentation. Importantly, fibroblasts were grown on the scaffolds and the expression levels of the marker genes, which are relevant for wound healing and proliferation, were assessed in order to reveal the effect of the 3D-scaffold microenvironment of the cells.
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26.
  • Scheidl, Stefan Johannes, 1972, et al. (författare)
  • mRNA expression profiling of laser microbeam microdissected cells from slender embryonic structures.
  • 2002
  • Ingår i: The American journal of pathology. - 0002-9440. ; 160:3, s. 801-13
  • Tidskriftsartikel (refereegranskat)abstract
    • Microarray hybridization has rapidly evolved as an important tool for genomic studies and studies of gene regulation at the transcriptome level. Expression profiles from homogenous samples such as yeast and mammalian cell cultures are currently extending our understanding of biology, whereas analyses of multicellular organisms are more difficult because of tissue complexity. The combination of laser microdissection, RNA amplification, and microarray hybridization has the potential to provide expression profiles from selected populations of cells in vivo. In this article, we present and evaluate an experimental procedure for global gene expression analysis of slender embryonic structures using laser microbeam microdissection and laser pressure catapulting. As a proof of principle, expression profiles from 1000 cells in the mouse embryonic (E9.5) dorsal aorta were generated and compared with profiles for captured mesenchymal cells located one cell diameter further away from the aortic lumen. A number of genes were overexpressed in the aorta, including 11 previously known markers for blood vessels. Among the blood vessel markers were endoglin, tie-2, PDGFB, and integrin-beta1, that are important regulators of blood vessel formation. This demonstrates that microarray analysis of laser microbeam micro-dissected cells is sufficiently sensitive for identifying genes with regulative functions.
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27.
  • Svanström, Andreas, et al. (författare)
  • The Effect of Hypoxic and Normoxic Culturing Conditions in Different Breast Cancer 3D Model Systems
  • 2021
  • Ingår i: Frontiers in Bioengineering and Biotechnology. - : Frontiers Media S.A.. - 2296-4185. ; 9
  • Tidskriftsartikel (refereegranskat)abstract
    • The field of 3D cell cultures is currently emerging, and material development is essential in striving toward mimicking the microenvironment of a native tissue. By using the response of reporter cells to a 3D environment, a comparison between materials can be assessed, allowing optimization of material composition and microenvironment. Of particular interest, the response can be different in a normoxic and hypoxic culturing conditions, which in turn may alter the conclusion regarding a successful recreation of the microenvironment. This study aimed at determining the role of such environments to the conclusion of a better resembling cell culture model to native tissue. Here, the breast cancer cell line MCF7 was cultured in normoxic and hypoxic conditions on patient-derived scaffolds and compared at mRNA and protein levels to cells cultured on 3D printed scaffolds, Matrigel, and conventional 2D plastics. Specifically, a wide range of mRNA targets (40), identified as being regulated upon hypoxia and traditional markers for cell traits (cancer stem cells, epithelial–mesenchymal transition, pluripotency, proliferation, and differentiation), were used together with a selection of corresponding protein targets. 3D cultured cells were vastly different to 2D cultured cells in gene expression and protein levels on the majority of the selected targets in both normoxic and hypoxic culturing conditions. By comparing Matrigel and 3DPS-cultured cells to cells cultured on patient-derived scffolds, differences were also noted along all categories of mRNA targets while specifically for the GLUT3 protein. Overall, cells cultured on patient-derived scaffolds closely resembled cells cultured on 3D printed scaffolds, contrasting 2D and Matrigel-cultured cells, regardless of a normoxic or hypoxic culturing condition. Thus, these data support the use of either a normoxic or hypoxic culturing condition in assays using native tissues as a blueprint to optimize material composition. Copyright © 2021 Svanström, Rosendahl, Salerno, Jonasson, Håkansson, Ståhlberg and Landberg.
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28.
  • von Kieseritzky, J., et al. (författare)
  • DendroPrime as an adhesion barrier on fracture fixation plates: an experimental study in rabbits
  • 2020
  • Ingår i: Journal of Hand Surgery-European Volume. - : SAGE Publications. - 1753-1934 .- 2043-6289. ; 45:7, s. 742-747
  • Tidskriftsartikel (refereegranskat)abstract
    • We tested the anti-adhesional effect of a new thiol-ene-based coating in a rabbit model. In 12 New Zealand white rabbits, the periosteum and cortex of the proximal phalanx of the second toe of both hind paws was scratched. Stainless steel plates were fixated with screws. One plate was coated with DendroPrime and the other left bare. The non-operated second toes of both hind paws of an additional four rabbits served as controls. Seven weeks after surgery, the soft tissue adhesion to the plates was evaluated macroscopically, and joint mobility was measured biomechanically. Toe joint mobility was about 20% greater and statistically significant in specimens with coated plates compared with the bare plates. Soft tissue overgrowth and, in some cases, synovitis or adhesions between the plate and the tendon were observed on all bare plates but not on any of the coated plates. We conclude that the thiol-ene-based coating can improve joint mobility by about 20%. This material has a potential to reduce adhesion around plates in fracture surgery.
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