Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteocond...Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteoconductivity and osteoinductivity is required for clinical therapy.Recently,the three-dimensional(3D)kagome structure has been shown to be advantageous for bone tissue regeneration due to its mechanical properties.In this study,a polycaprolactone(PCL)kagome-structure scaffold containing a hyaluronic acid(HA)-based hydrogel was fabricated using a 3D printing technique.The retention capacity of the hydrogel in the scaffold was assessed in vivo with a rat calvaria subcutaneous model for 3 weeks,and the results were compared with those obtained with conventional 3D-printed PCL grid-structure scaffolds containing HA-based hydrogel and bulk-type HA-based hydrogel.The retained hydrogel in the kagome-structure scaffold was further evaluated by in vivo imaging system analysis.To further reinforce the osteoinductivity of the kagome-structure scaffold,a PCL kagome-structure scaffold with bone morphogenetic protein-2(BMP-2)containing HA hydrogel was fabricated and implanted in a calvarial defect model of rabbits for 16 weeks.The bone regeneration characteristics were evaluated with hematoxylin and eosin(H&E),Masson’s trichrome staining,and micro-CT image analysis.展开更多
BACKGROUND Blood-brain barrier(BBB)disruption plays an important role in the development of neurological dysfunction in ischemic stroke.However,diagnostic modalities that can clearly diagnose the degree of BBB disrupt...BACKGROUND Blood-brain barrier(BBB)disruption plays an important role in the development of neurological dysfunction in ischemic stroke.However,diagnostic modalities that can clearly diagnose the degree of BBB disruption in ischemic stroke are limited.Here,we describe two cases in which the usefulness of dynamic contrastenhanced magnetic resonance imaging(DCE-MRI)in detecting BBB disruption was evaluated after treatment of acute ischemic stroke using two different methods.CASE SUMMARY The two patients of similar age and relatively similar cerebral infarction locations were treated conservatively or with thrombectomy,although their sex was different.As a result of analysis by performing DCE-MRI,it was confirmed that BBB disruption was significantly less severe in the patient who underwent thrombectomy(P=3.3×10^(-7)),whereas the average Ktrans of the contralateral hemisphere in both patients was similar(2.4×10^(-5)min^(-1) and 2.0×10^(-5)min^(-1)).If reperfusion is achieved through thrombectomy,it may indicate that the penumbra can be saved and BBB recovery can be promoted.CONCLUSION Our cases suggest that BBB disruption could be important if BBB permeability is used to guide clinical treatment.展开更多
Recently,research has been conducted to assist in the processing and analysis of histopathological images using machine learning algorithms.In this study,we established machine learning-based algorithms to detect phot...Recently,research has been conducted to assist in the processing and analysis of histopathological images using machine learning algorithms.In this study,we established machine learning-based algorithms to detect photothrombotic lesions in histological images of photothrombosis-induced rabbit brains.Six machine learning-based algorithms for binary classification were applied,and the accu-racies were compared to classify normal tissues and photothrombotic lesions.The lesion classification model consisting of a 3-layered neural network with a rectified linear unit(ReLU)activation function,Xavier initialization,and Adam optimization using datasets with a unit size of 128×128 pixels yielded the highest accuracy(0.975).In the validation using the tested histological images,it was confirmed that the model could identify regions where brain damage occurred due to photochemical ischemic stroke.Through the development of machine learning-based photothrombotic lesion classi-fication models and performance comparisons,we confirmed that machine learning algorithms have the potential to be utilized in histopathology and various medical diagnostic techniques.展开更多
Among many biomaterials,gelatin methacrylate(GelMA),a photocurable protein,has been widely used in 3D bioprinting process owing to its excellent cellular responses,biocompatibility and biodegradability.However,GelMA s...Among many biomaterials,gelatin methacrylate(GelMA),a photocurable protein,has been widely used in 3D bioprinting process owing to its excellent cellular responses,biocompatibility and biodegradability.However,GelMA still shows a low processability due to the severe temperature dependence of viscosity.To overcome this obstacle,we propose a two-stage temperature control system to effectively control the viscosity of GelMA.To optimize the process conditions,we evaluated the temperature of the cooling system(jacket and stage).Using the established system,three GelMA scaffolds were fabricated in which different concentrations(0,3 and 10 wt%)of silanated silica particles were embedded.To evaluate the performances of the prepared scaffolds suitable for hard tissue regeneration,we analyzed the physical(viscoelasticity,surface roughness,compressive modulus and wettability)and biological(human mesenchymal stem cells growth,western blotting and osteogenic differentiation)properties.Consequently,the composite scaffold with greater silica contents(10 wt%)showed enhanced physical and biological performances including mechanical strength,cell initial attachment,cell proliferation and osteogenic differentiation compared with those of the controls.Our results indicate that the GelMA/silanated silica composite scaffold can be potentially used for hard tissue regeneration.展开更多
基金supported by the Korea Health Technology R&D Project through the Korea Health Industry Development Institute(KHIDI),the Ministry of Health&Welfare,Republic of Korea(Grant Number:HI14C2143)the National Research Foundation of Korea(NRF)grant funded by the Korea government(MIST)(NRF-2021R1A2C2009665)。
文摘Osteoconductive function is remarkably low in bone disease in the absence of bone tissue surrounding the grafting site,or if the bone tissue is in poor condition.Thus,an effective bone graft in terms of both osteoconductivity and osteoinductivity is required for clinical therapy.Recently,the three-dimensional(3D)kagome structure has been shown to be advantageous for bone tissue regeneration due to its mechanical properties.In this study,a polycaprolactone(PCL)kagome-structure scaffold containing a hyaluronic acid(HA)-based hydrogel was fabricated using a 3D printing technique.The retention capacity of the hydrogel in the scaffold was assessed in vivo with a rat calvaria subcutaneous model for 3 weeks,and the results were compared with those obtained with conventional 3D-printed PCL grid-structure scaffolds containing HA-based hydrogel and bulk-type HA-based hydrogel.The retained hydrogel in the kagome-structure scaffold was further evaluated by in vivo imaging system analysis.To further reinforce the osteoinductivity of the kagome-structure scaffold,a PCL kagome-structure scaffold with bone morphogenetic protein-2(BMP-2)containing HA hydrogel was fabricated and implanted in a calvarial defect model of rabbits for 16 weeks.The bone regeneration characteristics were evaluated with hematoxylin and eosin(H&E),Masson’s trichrome staining,and micro-CT image analysis.
基金Supported by the National Research Foundation of Korea grant,No.2019M3E5D1A02069399
文摘BACKGROUND Blood-brain barrier(BBB)disruption plays an important role in the development of neurological dysfunction in ischemic stroke.However,diagnostic modalities that can clearly diagnose the degree of BBB disruption in ischemic stroke are limited.Here,we describe two cases in which the usefulness of dynamic contrastenhanced magnetic resonance imaging(DCE-MRI)in detecting BBB disruption was evaluated after treatment of acute ischemic stroke using two different methods.CASE SUMMARY The two patients of similar age and relatively similar cerebral infarction locations were treated conservatively or with thrombectomy,although their sex was different.As a result of analysis by performing DCE-MRI,it was confirmed that BBB disruption was significantly less severe in the patient who underwent thrombectomy(P=3.3×10^(-7)),whereas the average Ktrans of the contralateral hemisphere in both patients was similar(2.4×10^(-5)min^(-1) and 2.0×10^(-5)min^(-1)).If reperfusion is achieved through thrombectomy,it may indicate that the penumbra can be saved and BBB recovery can be promoted.CONCLUSION Our cases suggest that BBB disruption could be important if BBB permeability is used to guide clinical treatment.
基金This research was supported by grants from the Korea Health Technology R&D Project through the Korea Health Industry Development Institute(KHIDI)funded by the Ministry of Health&Welfare(Hl17C1501)from Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science&ICT(NRF-2020R1C1C1012230)S.H,Cho was supported by the semester internship program between Daegu Catholic University and Daegu-Gyeongbuk Medical Innovation Foundation.
文摘Recently,research has been conducted to assist in the processing and analysis of histopathological images using machine learning algorithms.In this study,we established machine learning-based algorithms to detect photothrombotic lesions in histological images of photothrombosis-induced rabbit brains.Six machine learning-based algorithms for binary classification were applied,and the accu-racies were compared to classify normal tissues and photothrombotic lesions.The lesion classification model consisting of a 3-layered neural network with a rectified linear unit(ReLU)activation function,Xavier initialization,and Adam optimization using datasets with a unit size of 128×128 pixels yielded the highest accuracy(0.975).In the validation using the tested histological images,it was confirmed that the model could identify regions where brain damage occurred due to photochemical ischemic stroke.Through the development of machine learning-based photothrombotic lesion classi-fication models and performance comparisons,we confirmed that machine learning algorithms have the potential to be utilized in histopathology and various medical diagnostic techniques.
基金This research was supported by Priority Research Centers Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2018R1D1A1B07049434)supported by the Technology development Program(S2839376)funded by the Ministry of SMEs and Startups(MSS,Korea)also was supported by Priority Research Centers Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF-2020R1F1A1056503).
文摘Among many biomaterials,gelatin methacrylate(GelMA),a photocurable protein,has been widely used in 3D bioprinting process owing to its excellent cellular responses,biocompatibility and biodegradability.However,GelMA still shows a low processability due to the severe temperature dependence of viscosity.To overcome this obstacle,we propose a two-stage temperature control system to effectively control the viscosity of GelMA.To optimize the process conditions,we evaluated the temperature of the cooling system(jacket and stage).Using the established system,three GelMA scaffolds were fabricated in which different concentrations(0,3 and 10 wt%)of silanated silica particles were embedded.To evaluate the performances of the prepared scaffolds suitable for hard tissue regeneration,we analyzed the physical(viscoelasticity,surface roughness,compressive modulus and wettability)and biological(human mesenchymal stem cells growth,western blotting and osteogenic differentiation)properties.Consequently,the composite scaffold with greater silica contents(10 wt%)showed enhanced physical and biological performances including mechanical strength,cell initial attachment,cell proliferation and osteogenic differentiation compared with those of the controls.Our results indicate that the GelMA/silanated silica composite scaffold can be potentially used for hard tissue regeneration.
