| 1. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 2. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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| 3. |
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| 5. |
- Gurzawska-Comis, Katarzyna, et al.
(författare)
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GUIDED BONE REGENERATION IN OSTEOPOROSIS BY PLANT-DERIVED NANOPARTICLES
- 2023
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Ingår i: Tissue Engineering. Part A. - : MARY ANN LIEBERT, INC. - 1937-3341 .- 1937-335X. ; 29:11-12, s. 576-577
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: The repair and treatment of large bone defects in patients with compromised bone metabolism due to ageing and medical conditions such as osteoporosis present often a clinical challenge. Therefore, adjunctive methods to enhance bone healing are needed.Bone tissue engineering with application of nanotechnology allows to construct biomaterials with desired properties being osteoconductive, osteoinductive and osteogenic.Aim / Hypothesis: The aim of our study was to promote bone regeneration using functionalised scaffold with Rhamnogalacturonan-I pectins (RG-I) in vitro and in vivo using aging and osteoporotic rodent models.Material and Methods: The biomaterials were poly(l-lactide-co-ε-caprolactone) scaffolds and the RG-I was from potato. The chemical and physical properties of functionalised biomaterials with RG-I nanoparticles were characterised using confocal and atomic force microscopy. Functionalised scaffolds with RG-I (tested sample) were evaluated in vitro with human osteoblasts from osteoporotic patients and their response was tested using real-time PCR. In vivo evaluation was performed using critical-size calvaria bone defect model in ageing and osteoporotic rat models. Scaffolds were implanted randomly in the calvaria defects of aged female Wistar rats (11-12 months old) and osteoporotic female Wistar rats induced by ovariectomy. The control was scaffold without RG-I. After 2 and 8 weeks, animals were euthanised. Harvested samples were analysed for osteogenic and inflammatory markers using real-time PCR. Bone formation was evaluated radiographically and histologically. The data was analysed using one-way ANOVA.Results: The chemical and physical properties results indicated success of the functionalisation of scaffolds with RG-I. Osteoblasts response suggested osteogenic (upregulation osteopontin, osteocalcin, collagen1, bone sialoprotein) and anti-inflammatory properties (downregulation IL-1, IL-8, TNF-alpha) on the scaffold functionalised with RG-I. The in vivo results in aged and osteoporotic rat calvaria model of early (2 weeks) bone regeneration showed increase of osteogenic markers and decrease of proinflammatory markers and RANKL, compared to control. In osteoporotic rat model at week 2 and 8 and in aged rat model at week 8, the mean percentage of BV / TV (bone volume / tissue volume) in the defect with RG-I scaffold was significantly greater than the defect with control. The histological evaluation in both rat models revealed larger areas of new bone formation in RG-I scaffolds than in control.Conclusion and Clinical implications: In conclusion, the plant-derived nanoparticles significantly increased osteogenic and decreased pro-inflammatory response in vitro and in vivo. These finding may have a crucial impact on bone repair process especially in elderly and osteoporotic patients.
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| 6. |
- Jain, Shubham, et al.
(författare)
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Engineering 3D degradable, pliable scaffolds toward adipose tissue regeneration; optimized printability, simulations and surface modification
- 2020
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Ingår i: Journal of Tissue Engineering. - : SAGE Publications. - 2041-7314. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- We present a solution to regenerate adipose tissue using degradable, soft, pliable 3D-printed scaffolds made of a medical-grade copolymer coated with polydopamine. The problem today is that while printing, the medical grade copolyesters degrade and the scaffolds become very stiff and brittle, being not optimal for adipose tissue defects. Herein, we have used high molar mass poly(L-lactide-co-trimethylene carbonate) (PLATMC) to engineer scaffolds using a direct extrusion-based 3D printer, the 3D Bioplotter (R). Our approach was first focused on how the printing influences the polymer and scaffold's mechanical properties, then on exploring different printing designs and, in the end, on assessing surface functionalization. Finite element analysis revealed that scaffold's mechanical properties vary according to the gradual degradation of the polymer as a consequence of the molar mass decrease during printing. Considering this, we defined optimal printing parameters to minimize material's degradation and printed scaffolds with different designs. We subsequently functionalized one scaffold design with polydopamine coating and conducted in vitro cell studies. Results showed that polydopamine augmented stem cell proliferation and adipogenic differentiation owing to increased surface hydrophilicity. Thus, the present research show that the medical grade PLATMC based scaffolds are a potential candidate towards the development of implantable, resorbable, medical devices for adipose tissue regeneration.
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| 7. |
- Jain, Shubham, et al.
(författare)
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Understanding of how the properties of medical grade lactide based copolymer scaffolds influence adipose tissue regeneration : Sterilization and a systematic in vitro assessment
- 2021
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Ingår i: Materials science & engineering. C, biomimetic materials, sensors and systems. - : Elsevier BV. - 0928-4931 .- 1873-0191. ; 124
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Tidskriftsartikel (refereegranskat)abstract
- Aliphatic polyesters are the synthetic polymers most commonly used in the development of resorbable medical implants / devices. Various three-dimensional (3D) scaffolds have been fabricated from these polymers and used in adipose tissue engineering. However, their systematic evaluation altogether lacks, which makes it difficult to select a suitable degradable polymer to design 3D resorbable implants and / or devices able to effectively mimic the properties of adipose tissue. Additionally, the impact of sterilization methods on the medical devices, if any, must be taken into account. We evaluate and compare five different medical-grade resorbable polyesters with l-lactide content ranging from 50 to 100 mol% and exhibiting different physiochemical properties depending on the comonomer (d-lactide, ε-caprolactone, glycolide, and trimethylene carbonate). The salt-leaching technique was used to prepare 3D microporous scaffolds. A comprehensive assessment of the physical, chemical, and mechanical properties of the scaffolds was carried out in PBS at 37 ° C. The cell-material interactions and the ability of the scaffolds to promote adipogenesis of human adipose tissue-derived stem cells were assessed in vitro. The diverse physical and mechanical properties of the scaffolds, due to the different composition of the copolymers, influenced human adipose tissue-derived stem cells proliferation and differentiation. Scaffolds made from polymers which were above their glass transition temperature and with low degree of crystallinity showed better proliferation and adipogenic differentiation of stem cells. The effect of sterilization techniques (electron beam and ethylene oxide) on the polymer properties was also evaluated. Results showed that scaffolds sterilized with the ethylene oxide method better retained their physical and chemical properties. Overall, the presented research provides (i) a detailed understanding to select a degradable polymer that has relevant properties to augment adipose tissue regeneration and can be further used to fabricate medical devices / implants; (ii) directions to prefer a sterilization method that does not change polymer properties. the presented research provides (i) a detailed understanding to select a degradable polymer that has relevant properties to augment adipose tissue regeneration and can be further used to fabricate medical devices / implants; (ii) directions to prefer a sterilization method that does not change polymer properties. the presented research provides (i) a detailed understanding to select a degradable polymer that has relevant properties to augment adipose tissue regeneration and can be further used to fabricate medical devices / implants; (ii) directions to prefer a sterilization method that does not change polymer properties.
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| 8. |
- Munir, Arooj, et al.
(författare)
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Efficacy of copolymer scaffolds delivering human demineralised dentine matrix for bone regeneration
- 2019
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Ingår i: Journal of Tissue Engineering. - : SAGE PUBLICATIONS INC. - 2041-7314. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Poly(L-lactide-co-epsilon-caprolactone) scaffolds were functionalised by 10 or 20 mu g/mL of human demineralised dentine matrix. Release kinetics up to 21 days and their osteogenic potential on human bone marrow stromal cells after 7 and 21 days were studied. A total of 390 proteins were identified by mass spectrometry. Bone regeneration proteins showed initial burst of release. Human bone marrow stromal cells were cultured on scaffolds physisorbed with 20 mu g/mL and cultured in basal medium (DDM group) or physisorbed and cultured in osteogenic medium or cultured on non-functionalised scaffolds in osteogenic medium. The human bone marrow stromal cells proliferated less in demineralised dentine matrix group and activated ERK/1/2 after both time points. Cells on DDM group showed highest expression of IL-6 and IL-8 at 7 days and expressed higher collagen type 1 alpha 2, SPP1 and bone morphogenetic protein-2 until 21 days. Extracellular protein revealed higher collagen type 1 and bone morphogenetic protein-2 at 21 days in demineralised dentine matrix group. Cells on DDM group showed signs of mineralisation. The functionalised scaffolds were able to stimulate osteogenic differentiation of human bone marrow stromal cells.
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| 9. |
- Rashad, Ahmad, et al.
(författare)
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Coating 3D Printed Polycaprolactone Scaffolds with Nanocellulose Promotes Growth and Differentiation of Mesenchymal Stem Cells
- 2018
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 19:11, s. 4307-4319
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Tidskriftsartikel (refereegranskat)abstract
- 3D printed polycaprolactone (PCL) has potential as a scaffold for bone tissue engineering, but the hydrophobic surface may hinder optimal cell responses. The surface properties can be improved by coating the scaffold with cellulose nanofibrils material (CNF), a multiscale hydrophilic biocompatible biomaterial derived from wood. In this study, human bone marrow-derived mesenchymal stem cells were cultured on tissue culture plates (TCP) and 3D printed PCL scaffolds coated with CNF. Cellular responses to the surfaces (viability, attachment, proliferation, and osteogenic differentiation) were documented. CNF significantly enhanced the hydrophilic properties of PCL scaffolds and promoted protein adsorption. Live/dead staining and lactate dehydrogenase release assays confirmed that CNF did not inhibit cellular viability. The CNF between the 3D printed PCL strands and pores acted as a hydrophilic barrier, enhancing cell seeding efficiency, and proliferation. CNF supported the formation of a well-organized actin cytoskeleton and cellular production of vinculin protein on the surfaces of TCP and PCL scaffolds. Moreover, CNF-coated surfaces enhanced not only alkaline phosphatase activity, but also collagen Type-I and mineral formation. It is concluded that CNF coating enhances cell attachment, proliferation, and osteogenic differentiation and has the potential to improve the performance of 3D printed PCL scaffolds for bone tissue engineering.
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| 10. |
- Shanbhag, Siddharth, et al.
(författare)
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Characterization of Human Gingiva- and PDL-derived Progenitor Cells in Xeno-free Conditions
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Objectives: Periodontal tissues represent a clinically relevant and less invasive source of progenitor cells compared to bone marrow, for periodontal- and/or alveolar bone-tissue engineering (P-/BTE). The safety and efficacy of clinical-grade stem cells can be enhanced via substitution of xenogeneic supplements and three-dimensional (3-D) cell culture, respectively, to simulate the in vivo microenvironment more closely. The objective of this study was to comprehensively characterize progenitor cells derived from human gingiva (GPCs) and periodontal-ligament (PDL; PPCs) in xeno-free conditions for use in P-/BTE. Methods: In preliminary experiments, pooled human platelet lysate (PL) was identified as the optimal xeno-substitute for fetal bovine serum (FBS) in stem cell cultures. Primary GPCs and PPCs were isolated and expanded as monolayers in PL- and FBS-supplemented media; passage 3-5 cells were used in experiments. Bone marrow mesenchymal stem cells (BMSCs) were used as a reference. Growth kinetics were compared via cell proliferation and colony forming-unit (CFU) assays. GPCs and PPCs were characterized via cytometric expression of stromal markers, multi-lineage (osteogenic, adipogenic and chondrogenic) differentiation potential, and secretory cytokine profiles. 3-D sphere cultures of GPCs and PPCs were established, and the expression of stemness- and osteogenesis-related markers in 3-D and monolayer cultures was evaluated via gene expression and immunocytochemistry. Results: GPCs and PPCs in both FBS and PL showed characteristic fibroblastic morphology and stromal phenotype (highly positive for CD105/CD90/CD73 and negative for CD34/CD45/HLA-DR). Cell proliferation and CFU efficiency were superior in PL compared to FBS. GPCs and PPCs expanded in both PL and FBS showed multi-lineage differentiation comparable to BMSCs; notably, osteogenic differentiation was enhanced in GPCs expanded in PL. 3-D spheres of GPCs and PPCs were formed and maintained for up to 7 days in xeno-free suspension culture. Notably, expression of stemness- (Sox2, Oct4, Nanog) and osteogenesis-related markers (Runx2, Osx, BMP2) was significantly upregulated in GPC- and PPC-derived spheres vs. monolayers. Conclusions: PPCs and particularly GPCs, due to easy access, cultured in 3-D xeno-free conditions represents a promising strategy for P-/BTE. Student Presenter This abstract is based on research that was funded entirely or partially by an outside source: International Team for Implantology (117/2015), Helse Vest Norway (912048) Disclosure Statement: The submitter must disclose the names of the organizations with which any author have a relationship, the nature of the relationship, and the clinical or research area involved. The following is submitted: NONE
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| 11. |
- Suliman, Salwa, et al.
(författare)
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Immune-instructive copolymer scaffolds using plant-derived nanoparticles to promote bone regeneration
- 2022
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Ingår i: Inflammation and Regeneration. - : Springer Nature. - 1880-8190. ; 42:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Age-driven immune signals cause a state of chronic low-grade inflammation and in consequence affect bone healing and cause challenges for clinicians when repairing critical-sized bone defects in elderly patients. Methods Poly(l-lactide-co-e-caprolactone) (PLCA) scaffolds are functionalized with plant-derived nanoparticles from potato, rhamnogalacturonan-I (RG-I), to investigate their ability to modulate inflammation in vitro in neutrophils and macrophages at gene and protein levels. The scaffolds' early and late host response at gene, protein and histological levels is tested in vivo in a subcutaneous rat model and their potential to promote bone regeneration in an aged rodent was tested in a critical-sized calvaria bone defect. Significant differences were tested using one-way ANOVA, followed by a multiple-comparison Tukey's test with a p value <= 0.05 considered significant. Results Gene expressions revealed PLCA scaffold functionalized with plant-derived RG-I with a relatively higher amount of galactose than arabinose (potato dearabinated (PA)) to reduce the inflammatory state stimulated by bacterial LPS in neutrophils and macrophages in vitro. LPS-stimulated neutrophils show a significantly decreased intracellular accumulation of galectin-3 in the presence of PA functionalization compared to Control (unmodified PLCA scaffolds). The in vivo gene and protein expressions revealed comparable results to in vitro. The host response is modulated towards anti-inflammatory/ healing at early and late time points at gene and protein levels. A reduced foreign body reaction and fibrous capsule formation is observed when PLCA scaffolds functionalized with PA were implanted in vivo subcutaneously. PLCA scaffolds functionalized with PA modulated the cytokine and chemokine expressions in vivo during early and late inflammatory phases. PLCA scaffolds functionalized with PA implanted in calvaria defects of aged rats downregulating pro-inflammatory gene markers while promoting osteogenic markers after 2 weeks in vivo. Conclusion We have shown that PLCA scaffolds functionalized with plant-derived RG-I with a relatively higher amount of galactose play a role in the modulation of inflammatory responses both in vitro and in vivo subcutaneously and promote the initiation of bone formation in a critical-sized bone defect of an aged rodent. Our study addresses the increasing demand in bone tissue engineering for immunomodulatory 3D scaffolds that promote osteogenesis and modulate immune responses.
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| 12. |
- Yassin, Mohammed A., et al.
(författare)
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3D and Porous RGDC-Functionalized Polyester-Based Scaffolds as a Niche to Induce Osteogenic Differentiation of Human Bone Marrow Stem Cells
- 2019
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Ingår i: Macromolecular Bioscience. - : WILEY-V C H VERLAG GMBH. - 1616-5187 .- 1616-5195. ; 19:6
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Tidskriftsartikel (refereegranskat)abstract
- Polyester-based scaffolds covalently functionalized with arginine-glycine-aspartic acid-cysteine (RGDC) peptide sequences support the proliferation and osteogenic differentiation of stem cells. The aim is to create an optimized 3D niche to sustain human bone marrow stem cell (hBMSC) viability and osteogenic commitment, without reliance on differentiation media. Scaffolds consisting of poly(lactide-co-trimethylene carbonate), poly(LA-co-TMC), and functionalized poly(lactide) copolymers with pendant thiol groups are prepared by salt-leaching technique. The availability of functional groups on scaffold surfaces allows for an easy and straightforward method to covalently attach RGDC peptide motifs without affecting the polymerization degree. The strategy enables the chemical binding of bioactive motifs on the surfaces of 3D scaffolds and avoids conventional methods that require harsh conditions. Gene and protein levels and mineral deposition indicate the osteogenic commitment of hBMSC cultured on the RGDC functionalized surfaces. The osteogenic commitment of hBMSC is enhanced on functionalized surfaces compared with nonfunctionalized surfaces and without supplementing media with osteogenic factors. Poly(LA-co-TMC) scaffolds have potential as scaffolds for osteoblast culture and bone grafts. Furthermore, these results contribute to the development of biomimetic materials and allow a deeper comprehension of the importance of RGD peptides on stem cell transition toward osteoblastic lineage.
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