Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
2.
Nat Commun ; 12(1): 4161, 2021 07 06.
Artigo em Inglês | MEDLINE | ID: mdl-34230488

RESUMO

Given the pleiotropic nature of coding sequences and that many loci exhibit multiple disease associations, it is within non-coding sequence that disease-specificity likely exists. Here, we focus on joint disorders, finding among replicated loci, that GDF5 exhibits over twenty distinct associations, and we identify causal variants for two of its strongest associations, hip dysplasia and knee osteoarthritis. By mapping regulatory regions in joint chondrocytes, we pinpoint two variants (rs4911178; rs6060369), on the same risk haplotype, which reside in anatomical site-specific enhancers. We show that both variants have clinical relevance, impacting disease by altering morphology. By modeling each variant in humanized mice, we observe joint-specific response, correlating with GDF5 expression. Thus, we uncouple separate regulatory variants on a common risk haplotype that cause joint-specific disease. By broadening our perspective, we finally find that patterns of modularity at GDF5 are also found at over three-quarters of loci with multiple GWAS disease associations.


Assuntos
Éxons , Luxação do Quadril/genética , Luxação do Quadril/metabolismo , Osteoartrite do Joelho/genética , Osteoartrite do Joelho/metabolismo , Animais , Condrócitos , Modelos Animais de Doenças , Regulação da Expressão Gênica , Predisposição Genética para Doença , Estudo de Associação Genômica Ampla , Fator 5 de Diferenciação de Crescimento/genética , Fator 5 de Diferenciação de Crescimento/metabolismo , Humanos , Camundongos , Fenótipo , Sequências Reguladoras de Ácido Nucleico
3.
Med Eng Phys ; 93: 35-41, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34154773

RESUMO

One-in-five people suffer from chronic low back pain (LBP). The incidence of this disease has doubled since 1950s and affects not only the elderly, but also the young population. However, the mechanism of LBP is still unknown. A possible location where the LBP may develop is the facet joint and it has been revealed that the intervertebral disc (IVD) nucleotomy may be a trigger for LBP. The aim of the present study was to investigate the influence of IVD nucleotomy on the load sharing in the spinal facet joint under the loading scenarios of different postures. Finite element (FE) models of the intact and nucleotomised L4 - L5 spinal segments were generated from the clinical CT images. Seven human postures, including upright, 5° extension, 5° flexion, ± 6° lateral bending and ± 2° axial rotation, were simulated. The resultant forces in the fact joint were compared between the intact and the nucleotomised cases. It was revealed that the IVD nucleotomy significantly increased the forces in the facet joints under the loading scenarios of upright, 5° extension and 5° flexion. The IVD nucleotomy increased the force in the ipsilateral facet joint but decreased the force on the contralateral side under the loading scenarios of ± 2° axial rotation. However, the IVD nucleotomy made little influence on the resultant forces in both facet joints in the postures of ± 6° lateral bending. In conclusion, the IVD nucleotomy can cause an increase in the overall force in the facet joint, and thus may serve as a possible explanation for the LBP and a main contributing factor for the pain complaints.

4.
Rheumatol Ther ; 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33666893

RESUMO

INTRODUCTION: The objective of this study is to identify the potential risk factors for progression from subclinical to clinical psoriatic arthritis (PsA). METHODS: A retrospective, longitudinal, case-control study was conducted at a single hospital, including 25 patients with clinically confirmed PsA in the case group and 137 controls without confirmed PsA. All patients in both groups had a medical history of subclinical PsA. Various baseline covariates were collected from all patients when they had a status of subclinical PsA. Univariate, multivariate, stratified, and interaction analyses were employed to identify potential risk factors of transiting to clinical PsA from subclinical PsA. RESULTS: In multivariate logistic regression analysis, older age (OR 10.15, 95% CI 2.79-36.91, p = 0.00), alcohol drinking (OR 3.43, 95% CI 1.17-10.12, p = 0.03), elevated high-sensitivity C-reactive protein (hs-CRP) (OR 1.05, 95% CI 1.01-1.09, p = 0.03) were identified as risk factors for transition from subclinical to clinical PsA. Stratified and logistic regression analyses suggest a significant interaction between age and fatty liver. For patients aged less than 45 years old, the association between fatty liver and clinical PsA was statistically significant. CONCLUSIONS: Older age, alcohol drinking, elevated hs-CRP, and the presence of fatty liver at less than 45 years old appear to increase the risk of transition from subclinical to clinical PsA. These findings call for a need to manage these risk factors.

6.
J Mech Behav Biomed Mater ; 112: 104080, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32927278

RESUMO

In recent years, the triply periodic minimal surface (TPMS) has emerged as a new method for producing open cell porous scaffolds because of the superior properties, such as the high surface-to-volume ratio, the zero curvature, etc. On the other hand, the additive manufacturing (AM) technique has made feasible the design and development of TPMS scaffolds with complex microstructures. However, neither the discrepancy between the theoretically designed and the additively manufactured TPMS scaffolds nor the underlying mechanisms is clear so far. The aims of the present study were to quantify the discrepancies between the theoretically designed and the AM produced TPMS scaffolds and to reveal the underlying mechanisms, e.g., the effect of building orientation on the discrepancy. 24 Gyroid scaffolds were produced along the height and width directions of the scaffold using the selective laser melting (SLM) technique (i.e., 12 scaffolds produced in each direction). The discrepancies in the geometric and mechanical properties of the TPMS scaffolds were quantified. Regarding the geometric properties, the discrepancies in the porosity, the dimension and the three-dimensional (3D) geometry of the scaffolds were quantified. Regarding the mechanical properties, the discrepancies in the effective compressive modulus and the mechanical environment (strain energy density) of the scaffolds were evaluated. It is revealed that the porosity in the AM produced scaffold is approximately 12% lower than the designed value. There are approximately 68.1 ± 8.6% added materials in the AM produced scaffolds and the added materials are mostly distributed in the places opposite to the building orientation. The building orientation has no effect on the discrepancy in the scaffold porosity and no effect on the distribution of the added materials (p > 0.05). Regarding the mechanical properties, the compressive moduli of the scaffolds are 24.4% (produced along the height direction) and 14.6% (produced along the width direction) lower than the designed value and are 49.1% and 43.6% lower than the µFE counterparts, indicating that the imperfect bonding and the partially melted powders have a large contribution to the discrepancy in the compressive modulus of the scaffolds. Compared to the values in the theoretically designed scaffold, the strain energy densities have shifted towards the higher values in the AM produced scaffolds. The findings in the present study provide important information for the design and additive manufacturing of TPMS scaffolds.


Assuntos
Osso e Ossos , Engenharia Tecidual , Porosidade , Pressão , Tecidos Suporte
7.
PLoS One ; 15(9): e0238471, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32870933

RESUMO

Bone scaffolds are widely used as one of the main bone substitute materials. However, many bone scaffold microstructure topologies exist and it is still unclear which topology to use when designing scaffold for a specific application. The aim of the present study was to reveal the mechanism of the microstructure-driven performance of bone scaffold and thus to provide guideline on scaffold design. Finite element (FE) models of five TPMS (Diamond, Gyroid, Schwarz P, Fischer-Koch S and F-RD) and three traditional (Cube, FD-Cube and Octa) scaffolds were generated. The effective compressive and shear moduli of scaffolds were calculated from the mechanical analysis using the FE unit cell models with the periodic boundary condition. The scaffold permeability was calculated from the computational fluid dynamics (CFD) analysis using the 4×4×4 FE models. It is revealed that the surface-to-volume ratio of the Fischer-Koch S-based scaffold is the highest among the scaffolds investigated. The mechanical analysis revealed that the bending deformation dominated structures (e.g., the Diamond, the Gyroid, the Schwarz P) have higher effective shear moduli. The stretching deformation dominated structures (e.g., the Schwarz P, the Cube) have higher effective compressive moduli. For all the scaffolds, when the same amount of change in scaffold porosity is made, the corresponding change in the scaffold relative shear modulus is larger than that in the relative compressive modulus. The CFD analysis revealed that the structures with the simple and straight pores (e.g., Cube) have higher permeability than the structures with the complex pores (e.g., Fischer-Koch S). The main contribution of the present study is that the relationship between scaffold properties and the underlying microstructure is systematically investigated and thus some guidelines on the design of bone scaffolds are provided, for example, in the scenario where a high surface-to-volume ratio is required, it is suggested to use the Fischer-Koch S based scaffold.


Assuntos
Transplante Ósseo/métodos , Osso e Ossos/patologia , Tecidos Suporte/química , Substitutos Ósseos/farmacologia , Força Compressiva , Análise de Elementos Finitos , Hidrodinâmica , Teste de Materiais , Permeabilidade , Porosidade , Pressão , Estresse Mecânico , Engenharia Tecidual/métodos
8.
BMC Med Res Methodol ; 20(1): 152, 2020 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-32539721

RESUMO

BACKGROUND: In meta-analyses of a binary outcome, double zero events in some studies cause a critical methodology problem. The generalized linear mixed model (GLMM) has been proposed as a valid statistical tool for pooling such data. Three parameter estimation methods, including the Laplace approximation (LA), penalized quasi-likelihood (PQL) and adaptive Gauss-Hermite quadrature (AGHQ) were frequently used in the GLMM. However, the performance of GLMM via these estimation methods is unclear in meta-analysis with zero events. METHODS: A simulation study was conducted to compare the performance. We fitted five random-effects GLMMs and estimated the results through the LA, PQL and AGHQ methods, respectively. Each scenario conducted 20,000 simulation iterations. The data from Cochrane Database of Systematic Reviews were collected to form the simulation settings. The estimation methods were compared in terms of the convergence rate, bias, mean square error, and coverage probability. RESULTS: Our results suggested that when the total events were insufficient in either of the arms, the GLMMs did not show good point estimation to pool studies of rare events. The AGHQ method did not show better properties than the LA estimation in terms of convergence rate, bias, coverage, and possibility to produce very large odds ratios. In addition, although the PQL had some advantages, it was not the preferred option due to its low convergence rate in some situations, and the suboptimal point and variance estimation compared to the LA. CONCLUSION: The GLMM is an alternative for meta-analysis of rare events and is especially useful in the presence of zero-events studies, while at least 10 total events in both arms is recommended when employing GLMM for meta-analysis. The penalized quasi-likelihood and adaptive Gauss-Hermite quadrature are not superior to the Laplace approximation for rare events and thus they are not recommended.


Assuntos
Modelos Estatísticos , Simulação por Computador , Humanos , Funções Verossimilhança , Modelos Lineares , Razão de Chances , Revisões Sistemáticas como Assunto
9.
Environ Res ; 186: 109532, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32334170

RESUMO

On March 1, 2012, the Chinese government implemented the Administrative Measures on Heatstroke Prevention (AMHP2012) to combat the occupational health impacts of extreme heat, and reducing occupational injury was one of the main purposes. This study aimed at quantifying the intervention effects of the AMHP2012 on extreme heat-related occupational injuries and subsequent insurance payouts in Guangzhou, China. Data on occupational injuries and insurance payouts were collected from March 1, 2011, to February 28, 2013, from the occupational injury insurance system of Guangzhou. A quasi-experimental design with before-after control was adopted. Interrupted time series analysis was performed to quantify the change of occupational injuries and insurance payouts after policy implementation. The distributed lag non-linear model was used to explore whether injury claims and insurance payouts due to extreme heat decreased. A total of 9851 injury claims were included in the analysis. After policy implementation, the risk of occupational injuries and insurance payouts decreased by 13% (RR = 0.87, 95%CI: 0.75, 0.99) and 24% (RR = 0.76, 95% CI: 0.58, 0.94), respectively. The attributable fraction of extreme heat-related occupational injuries decreased from 3.17% (95%eCI: 1.35, 4.69) to 1.52% (95%eCI: -0.36, 3.15), which contributed to 0.86 million USD reduction of insurance payouts. Both males and females, low-educated, young and middle-aged workers, workers at small or medium-sized enterprises, engaging in manufacturing, and with both minor and severe injuries were apparently associated with decreased rates of extreme heat-related occupational injuries. The AMHP2012 policy contributed to the reduction of extreme heat-related occupational injuries and insurance payouts in Guangzhou, China, and this research provided novel evidence for decision-makers to better understand the necessity of implementing health protection policies among laborers under climate change.


Assuntos
Calor Extremo , Exposição Ocupacional , Traumatismos Ocupacionais , China/epidemiologia , Cidades , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Traumatismos Ocupacionais/epidemiologia , Traumatismos Ocupacionais/prevenção & controle
10.
Ann Plast Surg ; 84(5S Suppl 3): S222-S224, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32282417

RESUMO

At present, there is no uniform standard for the treatment of femoral neck fractures (FNFs) in young adults, and the current strategy is inclined to the native hip joint preservation. Femoral neck fractures in young adult are mostly caused by high-energy violence, and the blood supply of femoral head is severely damaged, which is prone to secondary femoral head avascular necrosis. In this article, we report 10 cases of young adult Garden III FNF treated with open reduction and internal fixation (ORIF) and microsurgical exploration of the superior retinacular vessels from 2015 to 2018, to more intuitively understand the involvement of superior retinacular vessels after displaced FNF in young adults. The results show that the SRA injury of Garden III FNF could be categorized into 3 types (type A-C), type A (6/10): the SRA vessels were kept intact, while they were pulled or compressed by displaced fracture fragment and could be revascularized by reduction; type B (3/10): the SRA vessels were avulsed with the superior retinaculum attachment avulsion fracture and could not be revascularized by reduction; and type C (1/10): the SRA vessels were ruptured, and the remnant of the vessel is present, which can be revascularized by vascular anastomosis. The previously mentioned results showed that the vascular damage of femoral head in Garden III FNF is quite complicated and might have the potential for being further classified into several subtypes.


Assuntos
Fraturas do Colo Femoral , Necrose da Cabeça do Fêmur , Fraturas do Colo Femoral/cirurgia , Fixação Interna de Fraturas , Humanos , Redução Aberta , Adulto Jovem
11.
Biomaterials ; 238: 119829, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32058868

RESUMO

Magnesium (Mg)-based metals can be used as next-generation fracture internal fixation devices due to their specific properties. We used vascularized bone grafting fixed by degradable pure Mg screws and obtained satisfactory results in the treatment of osteonecrosis of the femoral head. However, the mechanical properties of these screws make them weaker than those made of traditional metals. In particular, one of the main challenges of using screws made of Mg-based metals is their application in fixation at important weight-bearing sites in the human body. Femoral neck fracture is a common clinical injury. In this injury, the large bearing stress at the junction requires a fixation device with extremely high mechanical strength. Surgery and appropriate internal fixation can accelerate the healing of femoral neck fractures. Traditional internal fixation devices have some disadvantages after surgery, including stress shielding effects and the need for secondary surgery to remove screws. On the basis of previous work, we developed high-strength pure Mg screws for femoral neck fractures. In this study, we describe the first use of high-purity Mg to prepare large-size weight-bearing screws for the fixation of femoral neck fractures in goats. We then performed a 48 weeks follow-up study using in vivo transformation experiments. The results show that these biodegradable high-purity Mg weight-bearing screws had sufficient mechanical strength and a degradation rate compatible with bone repair. Furthermore, good bone formation was achieved during the degradation process and reconstruction of the bone tissue and blood supply of the femoral head and femoral neck. This study provides a basis for future research on the clinical transformation of biodegradable high-purity Mg weight-bearing screws.


Assuntos
Fraturas do Colo Femoral , Parafusos Ósseos , Fraturas do Colo Femoral/cirurgia , Seguimentos , Fixação Interna de Fraturas , Consolidação da Fratura , Humanos , Magnésio , Suporte de Carga
12.
Sci Total Environ ; 711: 135098, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32000339

RESUMO

Diabetes is a major public health problem globally, and heat exposure may be a potential risk factor for death among diabetes. This study examines the association between heat and diabetes mortality in different regions of Thailand and investigates whether heat effects are modified by regional greenness. Daily temperature and daily diabetes deaths data were obtained for 60 provinces of Thailand during 2000-2008. A case-crossover analysis was conducted to quantify the odds of heat-related death among diabetes. Meta-regression was then used to examine potential modification effects of regional greenness (as represented by the Normalized Difference Vegetation Index) on heat-related mortality. A strong association between heat and diabetes mortality was found in Thailand, with important regional variations. Nationally, the pooled odds ratio of diabetes mortality was 1.10 (95% confidence interval (CI): 1.06-1.14) for heat (90th percentile of temperature) and 1.20 (95% CI: 1.10-1.30) for extreme heat (99th percentile of temperature) compared with the minimum mortality temperature, across lag 0-1 days. Central and northeast Thailand were the most vulnerable regions. Regional greenness modified the effects of heat, with lower mortality impacts in areas of higher levels of greenness. In conclusion, heat exposure increases mortality risk in diabetes, with large geographical variations in risk suggesting the need for region-specific public health strategies. Increasing greenness levels may help to reduce the burden of heat on diabetes in Thailand against the backdrop of a warming climate.


Assuntos
Diabetes Mellitus , Diabetes Mellitus/mortalidade , Temperatura Alta , Humanos , Temperatura , Tailândia/epidemiologia
13.
Sci Total Environ ; 708: 135096, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31806312

RESUMO

Cadmium (Cd) is one of the most hazardous trace metals, and rapeseed is a major oil crop over the world with considerable lignocellulose residues applicable for trace metal phytoremediation and cellulosic ethanol co-production. In this study, we examined that two distinct rapeseed cultivars could accumulate Cd at 72.48 and 43.70 ug/g dry stalk, being the highest Cd accumulation among all major agricultural food crops as previously reported. The Cd accumulation significantly increased pectin deposition as a major factor for trace metal association with lignocellulose. Meanwhile, the Cd-accumulated rapeseed stalks contained much reduced wall polymers (hemicellulose, lignin) and cellulose degree of polymerization, leading to improved lignocellulose enzymatic hydrolysis. Notably, three optimal chemical pretreatments were performed for enhanced biomass enzymatic saccharification and bioethanol production by significantly increasing cellulose accessibility and lignocellulose porosity, along with a complete Cd release for collection and recycling. Hence, this study proposed a mechanism model interpreting why rapeseed stalks are able to accumulate much Cd and how the Cd-accumulated stalks are of enhanced biomass saccharification. It has also provided a powerful technology for both cost-effective Cd phytoremediation and value-added bioethanol co-production with minimum waste release.


Assuntos
Brassica napus , Brassica rapa , Biodegradação Ambiental , Biomassa , Cádmio , Hidrólise , Lignina
14.
Surg Technol Int ; 35: 406-409, 2019 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-31687779

RESUMO

Tantalum rod implantation with vascularized bone transplantation has been reported to be an effective method for the treatment of osteonecrosis of the femoral head (ONFH). However, long-term follow-up results were unclear. Sixty-five patients (71 hips) with ONFH treated with this technique were retrospectively reviewed. According to the Association Research Circulation Osseous (ARCO) classification, 21 hips were stage II, 30 were stage III, and 15 were stage IV. Sixty-one patients (66 hips) were followed for more than 10 years. Fifteen hips had to be converted to total hip arthroplasty (THA), the proportion of THA conversion surgery over 10 years postoperative was 4.76% for stage II, 16.7% for stage III, and 60% for stage IV, respectively. The 10-year joint-preserving success rate of the entire group was 77.2%. The Harris Hip Score (HHS) in the patients not receiving THA therapy increased from a mean of 51.35 points (ranged from 32 to 62 points) to 90.12 points (ranged from 72 to 99 points). The technique of tantalum rod implantation with vascularized bone grafting was an effective joint-preserving method for the treatment of ARCO stage II-III ONFH.


Assuntos
Transplante Ósseo , Necrose da Cabeça do Fêmur , Cabeça do Fêmur/cirurgia , Necrose da Cabeça do Fêmur/cirurgia , Seguimentos , Humanos , Estudos Retrospectivos , Análise de Sobrevida , Tantálio , Resultado do Tratamento
15.
BMC Med Res Methodol ; 19(1): 78, 2019 04 11.
Artigo em Inglês | MEDLINE | ID: mdl-30975073

RESUMO

BACKGROUND: To investigate the prevalence of protocol registration (or development) among published dose-response meta-analyses (DRMAs), and whether DRMAs with a protocol are better than those not. METHODS: Three databases were searched for eligible DRMAs. The modified AMSTAR (14 items) and PRISMA checklists (26 items) were used to assess the methodological and reporting quality, with each item assigned 1 point if it met the requirement or 0 if not. We matched (1,2) DRMAs with registered or published protocol to those not, by region and publication years. The summarized quality score and compliance rate of each item were compared between the two groups. Multivariable regression was employed to see if protocol registration or development was associated with total quality score. RESULTS: We included 529 DRMAs, with 45 (8.51%) completed protocol registration or development. We observed a higher methodological score for DRMAs with protocol than the matched controls (9.47 versus 8.58, P <  0.01); this embodied in 4 out of 14 items of AMSTAR [e.g., Duplicate data extraction (rate difference, RD = 0.17, 95% CI: 0.04, 0.30; P = 0.01). A higher reporting score (cubic transformed) for DRMAs with protocol than the matched controls was also observed (11,875.00 versus 10,229.53, P <  0.01); which embodied in 6 out of 26 items of PRISMA [e.g. Describe methods for publication bias (RD = 0.08, 95% CI: 0.01, 0.14; P = 0.02)]. Regression analysis suggested positive association between protocol registration or development and total reporting score (P = 0.012) while not for methodological score (P = 0.87). CONCLUSIONS: Only a small proportion of DRMAs completed protocol registration or development, and those with protocol were better reported than those not. Protocol registration or development is highly desirable.


Assuntos
Metanálise como Assunto , Publicações Periódicas como Assunto , Projetos de Pesquisa/normas , Relatório de Pesquisa/normas , Literatura de Revisão como Assunto , Humanos
16.
Stem Cell Res Ther ; 10(1): 72, 2019 03 05.
Artigo em Inglês | MEDLINE | ID: mdl-30837004

RESUMO

BACKGROUND: The body is unable to repair and regenerate large area bone defects. Moreover, the repair capacity of articular cartilage is very limited. There has long been a lack of effective treatments for osteochondral lesions. The engineered tissue with biphase synthetic for osteochondral repair has become one of the hot research fields over the past few years. In this study, an integrated biomanufacturing platform was constructed with bone marrow mesenchymal stem cells (BMSCs)/porous tantalum (pTa) associated with chondrocytes/collagen membranes (CM) to repair large osteochondral defects in load-bearing areas of goats. METHODS: Twenty-four goats with a large osteochondral defect in the femoral heads of the left hind legs were randomly divided into three groups: eight were treated with chondrocytes/CM-BMSCs/pTa, eight were treated with pure CM-pTa composite, and the other eight goats were untreated. The repair effect was assessed by X-ray, gross observation, and histomorphology for 16 weeks after the operation. In addition, the biocompatibility of chondrocytes/CM-BMSCs/pTa was observed by flow cytometry, CCK8, immunocytochemistry, and Q-PCR. The characteristics of the chondrocytes/CM-BMSCs/pTa were evaluated using both scanning electron microscopy and mechanical testing machine. RESULTS: The integrated repair material consists of pTa, injectable fibrin sealant, and CM promoted adhesion and growth of BMSCs and chondrocytes. pTa played an important role in promoting the differentiation of BMSCs into osteoblasts. Three-dimensional CM maintained the phenotype of chondrocytes successfully and expressed chondrogenic genes highly. The in vivo study showed that after 16 weeks from implantation, osteochondral defects in almost half of the femoral heads had been successfully repaired by BMSC-loaded pTa associated with biomimetic 3D collagen-based scaffold. CONCLUSIONS: The chondrocytes/CM-BMSCs/pTa demonstrated significant therapeutic efficacy in goat models of large osteochondral defect. This provides a novel therapeutic strategy for large osteochondral lesions in load-bearing areas caused by severe injury, necrosis, infection, degeneration, and tumor resection with a high profile of safety, effectiveness, and simplicity.


Assuntos
Cartilagem Articular/crescimento & desenvolvimento , Condrócitos/efeitos dos fármacos , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/efeitos dos fármacos , Animais , Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Regeneração Óssea/efeitos dos fármacos , Cartilagem Articular/efeitos dos fármacos , Condrócitos/metabolismo , Colágeno/química , Colágeno/farmacologia , Cabras/crescimento & desenvolvimento , Membranas Artificiais , Porosidade , Tantálio/química , Tecidos Suporte/química
17.
PeerJ ; 7: e6295, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30697486

RESUMO

Objective: In evidence synthesis practice, dealing with binary rare adverse events (AEs) is a challenging problem. The pooled estimates for rare AEs through traditional inverse variance (IV), Mantel-Haenszel (MH), and Yusuf-Peto (Peto) methods are suboptimal, as the biases tend to be large. We proposed the "one-stage" approach based on multilevel variance component logistic regression (MVCL) to handle this problem. Methods: We used simulations to generate trials of individual participant data (IPD) with a series of predefined parameters. We compared the performance of the MVCL "one-stage" approach and the five classical methods (fixed/random effect IV, fixed/random effect MH, and Peto) for rare binary AEs under different scenarios, which included different sample size setting rules, effect sizes, between-study heterogeneity, and numbers of studies in each meta-analysis. The percentage bias, mean square error (MSE), coverage probability, and average width of the 95% confidence intervals were used as performance indicators. Results: We set 52 scenarios and each scenario was simulated 1,000 times. Under the rule of three (a sample size setting rule to ensure a 95% chance of detecting at least one AE case), the MVCL "one-stage" IPD method had the lowest percentage bias in most of the situations and the bias remained at a very low level (<10%), when compared to IV, MH, and Peto methods. In addition, the MVCL "one-stage" IPD method generally had the lowest MSE and the narrowest average width of 95% confidence intervals. However, it did not show better coverage probability over the other five methods. Conclusions: The MVCL "one-stage" IPD meta-analysis is a useful method to handle binary rare events and superior compared to traditional methods under the rule of three. Further meta-analyses may take account of the "one-stage" IPD method for pooling rare event data.

18.
J Clin Epidemiol ; 107: 1-11, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30445166

RESUMO

OBJECTIVES: To investigate methodological quality of published dose-response meta-analysis (DRMA) and explore study characteristics associated with the quality. STUDY DESIGN AND SETTING: We searched three databases for published DRMAs and used a modified AMSTAR (15 items) checklist to assess the methodological quality. We summarized the compliance of those DRMAs to the AMSTAR items and used multivariable regression analysis to explore the association between prespecified study characteristics with the overall methodological quality. RESULTS: We identified 529 DRMAs. Of the methodological quality items, six were well complied (80% or more) and six poorly complied (30% or fewer) by these DRMAs. The median score was nine points [first and third quartile: 7, 10] and only 64/529 had score over 10 points. Regression analysis suggested that studies with more authors (ß = 0.19; 95% confidence interval [CI]: 0.05, 0.33), published more recently (ß = 0.29; 95% CI: 0.21, 0.36), with financial support (ß = 0.41; 95% CI: 0.13, 0.70), conducted by authors from European (other regions vs. European, ß = -0.68; 95% CI: -1.05, -0.31) were associated with better methodological quality. CONCLUSION: The methodological quality of published DRMAs was suboptimal. Substantial efforts are warranted to improve the quality, including developing methodology guideline, involving more methodological trained authors, and so forth.


Assuntos
Metanálise como Assunto , Relatório de Pesquisa/normas , Estudos Transversais , Relação Dose-Resposta a Droga , Humanos , Análise de Regressão
19.
BMC Med Res Methodol ; 18(1): 157, 2018 11 29.
Artigo em Inglês | MEDLINE | ID: mdl-30497389

RESUMO

BACKGROUND: Dose-response meta-analysis (DRMA) is a useful tool to investigate potential dose-response relationship between certain exposure or intervention and the outcome of interest. A large number of DRMAs have been published in the past several years. However, the standard of reporting for such studies is not known. METHODS: Medline, Embase, and Wiley Library were searched for systematic reviews with DRMAs (SR-DRMAs) published from January 2011 to July 2017. We used the combination of PRISMA and MOOSE statements, containing 33 items, to assess the reporting of included SR-DRMAs. The adherence of reporting was defined as the proportion of SR-DRMAs meeting the reporting requirement of an item. We explored the association between five pre-specified variables with the total score of reporting on both fully as well as each domain of the checklist. RESULTS: In total, 529 SR-DRMAs were eligible. Ten out of 33 items were under reported, and this mainly refers to the methods domain: only a small proportion of SR-DRMAs stated whether a review protocol existed (45, 8.5%); clarified the qualifications of searchers (1.7%); presented full electronic search strategy (25.9%); described any effort to include all available studies (22.9%), described methods for languages other than English (27.4%), and stated the process for selecting studies (20.2%). Multiple regression analysis suggested that studies with more authors (regression coefficient = 0.78; 95% CI: 0.35, 1.20; P <  0.001), published more recently (regression coefficient = 0.38; 95% CI: 0.28 to 0.47; trend P <  0.001), used reporting guideline (regression coefficient = 0.98; 95% CI: 0.68 to 1.32; P <  0.001), and involvement of methodologist (regression coefficient = 0.86; 95% CI: 0.42 to 1.32; P <  0.001) were associated with higher score of reporting. Further regression suggested that the improvement on the quality mainly concentrated on the methods and results domains. CONCLUSIONS: The reporting of SR-DRMAs needs to be further improved, particularly in the issues refer to the methods. The quality of reporting may improve when involving more authors and methodologists and employing any reporting guidelines.


Assuntos
Metanálise como Assunto , Publicações Periódicas como Assunto/normas , Relatório de Pesquisa/normas , Revisões Sistemáticas como Assunto , Estudos Transversais , Confiabilidade dos Dados , Coleta de Dados/métodos , Coleta de Dados/normas , Relação Dose-Resposta a Droga , Humanos , Avaliação de Resultados em Cuidados de Saúde/métodos , Avaliação de Resultados em Cuidados de Saúde/normas
20.
Medicine (Baltimore) ; 97(38): e12400, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30235709

RESUMO

The aim of this study was to investigate the relationship between femoroacetabular impingement (FAI) and superior retinacular artery interruption using plain radiographs and digital subtraction angiography (DSA).Sixty-one patients included in this study were divided into 2 groups based on the superior retinacular artery integrity as evaluated on DSA images. Group A included intact arteries: 33 patients (24 men, 9 women,); group B included interrupted arteries: 28 patients (21 men, 7 women). The parameters of abnormal radiographic findings thought to be associated with FAI, including positive crossover or figure-of-eight sign of acetabulum, lateral center edge angle (LCEA) >40°, Tönnis angle <0°, positive posterior wall sign, alpha angle >50°, and coxa profunda, were evaluated in all patients through plain radiographs.The cross-over sign (Group A: 0, Group B: 8, P = .0035), LCEA (Group A: 1, Group B: 7, P = .0190), Tönnis angle (Group A: 3, Group B: 13, P = .0026), and alpha angle (Group A: 7, Group B: 17, P = .0039) differed significantly between both groups. However, there were no statistically significant differences in posterior wall sign (Group A: 9, Group B: 12, P = .3143) or coxa profunda (Group A: 12, Group B: 8, P = .7096).Patients with interrupted blood supply of the superior retinacular arteries displayed more parameters of abnormal radiographic findings associated with FAI thereby indicating potential correlation between FAI and the interruption of superior retinacular arteries.


Assuntos
Angiografia Digital/métodos , Impacto Femoroacetabular/diagnóstico por imagem , Artéria Femoral/diagnóstico por imagem , Acetábulo/irrigação sanguínea , Acetábulo/diagnóstico por imagem , Adulto , Estudos Cross-Over , Feminino , Impacto Femoroacetabular/patologia , Artéria Femoral/patologia , Quadril/irrigação sanguínea , Quadril/diagnóstico por imagem , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia/métodos , Estudos Retrospectivos , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...