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71.
Katherine A. Boyer Gary S. Beaupre Thomas P. Andriacchi 《Journal of biomechanics》2008,41(16):3360-3365
Gender differences in the incidence of symptomatic hip osteoarthritis (OA), changes in hip cartilage volume and hip joint space and rates hip arthroplasty of older people are reported in the literature. As the rate of progression of OA is in part mechanically modulated it is possible that this gender bias may be related to inherent differences (if they exist) in walking mechanics between older males and females. The purpose of this study was to examine potential mechanisms for gender differences in hip joint mechanics during walking by testing the hypotheses that females would exhibit higher hip flexion, adduction and internal rotation moments but not significantly greater normalized ground reaction forces (GRFs). Forty-two healthy subjects (21 male, 21 female), ages 50–79 yr were recruited for gait analysis. In support of the hypotheses, greater external hip adduction and internal rotation along with hip extension moments were found for females compared to males after normalizing for body size for all self-selected walking speeds. Differences in walking style (kinematics) were the main determinants in the joint kinetic differences as no differences in the normalized GRFs were found. As external joint moments are surrogate measures of the joint contact forces, the results of this study suggest the hip joint stress for the female population is higher compared to male population. This is in favor of a hypothesis that the increased joint contact stress in a female population could contribute to a greater joint degeneration at the hip in females as compared with males. 相似文献
72.
73.
Background and aimAβ1−42 is an amyloidogenic peptide found within senile plaques extracted from those who died with a diagnosis of Alzheimer’s disease. The potent neurotoxicity of this peptide is related to its propensity to form aggregated conformations in vivo, a process that is influenced by the species and concentration of metal ions present within the local environment. This study examines the impact of different metals upon the early aggregatory behaviour and size of Aβ1−42 under simulated physiological conditions.MethodsThe size and aggregatory behaviour of Aβ1−42 in the presence and absence of metal ions was monitored during the initial 30 min of fibril formation in real-time using dynamic light scattering.ResultsIntensity scattering measurements showed a clear tendency towards aggregation with regards to Aβ1−42 only solutions (10 μM). Both equimolar Al3+ & Cu2+ lowered and stabilised the dimensions of Aβ1−42 aggregates; however, a diminutive but significant increase in size was still observed over a 30-min period. While excess Al3+ continued to supress the size of Aβ1−42, a 10-fold increase in the concentration of Cu2+ accelerated peptide aggregation relative to that observed for equimolar metal but not compared to Aβ1−42 alone.ConclusionThese results infer that Al3+ ions stabilise and aid in the maintenance of smaller, toxic intermediates while excess Cu2+ facilitates the formation of larger, more inert, amorphous species exceeding 1 μm in size. Furthermore, we propose that metal-induced toxicity of Aβ1−42 is reflective of their ability to preserve smaller oligomeric species in vitro. 相似文献
74.
Rafael Bielza Galindo Jesús Llorente Gutiérrez José Luis Pérez González Asunción Mora Casado David Blanco Díaz Javier Escalera Alonso Adoración Morales Fernández Cristina Molano Ortiz Beredys Esmirla García López Nazaret del Amo del Arco Juan Pablo Barro Ordovas Estefanía Arias Muñana Marta Neira Álvarez David Sanz Rosa Jorge Fco. Gómez Cerezo 《Revista espa?ola de geriatría y gerontología》2018,53(1):38-44
Introduction
There are no previous studies evaluating the effect of intravenous iron therapy on functional and cognitive status of patients with hip fracture (HF).Material and methods
A single-centre randomised, placebo-controlled, double-blind and parallel treatment, clinical trial has been designed to assess the efficacy of intravenous iron therapy during the peri-operative period in elderly patients suffering from a HF. Blinding will be ensured by the packaging of the drug infusion system. On days 1, 3, and 5 from admission, the intervention group will receive 200 mg Venofer® (iron sucrose) diluted in 100 ml saline, and the control group 100 ml saline, also on days 1, 3 and 5. Patients will received conventional treatment in ortho-geriatric unit of the Hospital Infanta Sofia. Functional variables (activities of daily living and walking), cognitive (cognitive status and delirium), surgical, demographic and clinical characteristics will be collected during admission in order to assess the impact of treatment. A safety analysis of the treatment will also performed. Patients will be followed-up at 3, 6, and 12 months.Results
The study will attempt to provide evidence on the impact of the intravenous iron administration on functional recovery. It will be determined whether iron therapy negatively affects the incidence of post-operative delirium. Finally, report will be presented on the safety data of intravenous iron in elderly HF patients, as well as the impact on allogenic blood transfusion savings.Conclusions
The inclusion of elderly HF patients admitted to an ortho-geriatric unit, in a clinical trial, will help to improve the knowledge of the treatment impact on a usual scenario, and provide useful data for use in other units. 相似文献75.
Bruno César Feltes Conrado Pedebos Diego Bonatto Hugo Verli 《Biochimica et Biophysica Acta (BBA)/General Subjects》2018,1862(12):2579-2589
Background
Xeroderma Pigmentosum (XP) is a disease caused by mutations in the nucleotide excision repair (NER) pathway. Patients with XP exhibit a high propensity to skin cancers and some subtypes of XP can even present neurological impairments. During NER, DDB2 (XPE), in complex with DDB1 (DDB-Complex), performs the DNA lesion recognition. However, not much is known about how mutations found in XP patients affect the DDB2 structure and complex assembly. Thus, we searched for structural evidence associated with the role of three naturally occurring mutations found in XPE patients: R273H, K244E, and L350P.Methods
Each mutant was individually constructed and submitted to multiple molecular dynamics simulations, done in triplicate for each designed system. Additionally, Dynamic Residue Interaction Networks were designed for each system and analyzed parallel with the simulations.Results
DDB2 mutations promoted loss of flexibility in the overall protein structure, producing a different conformational behavior in comparison to the WT, especially in the region comprising residues 354 to 371. Furthermore, the DDB-complex containing the mutated forms of DDB2 showed distinct behaviors for each mutant: R273H displayed higher structural instability when complexed; L350P affected DDB1 protein-protein binding with DDB2; and K244E, altered the complex binding trough different ways than L350P.Conclusions
The data gathered throughout the analyses helps to enlighten the structural basis for how naturally occurring mutations found in XPE patients impact on DDB2 and DDB1 function.General significance
Our data influence not only on the knowledge of XP but on the DNA repair mechanisms of NER itself. 相似文献76.
Dynamical stress characterization and energy evaluation of single cardiac myocyte actuating on flexible substrate 总被引:2,自引:0,他引:2
Qin L Huang J Xiong C Zhang Y Fang J 《Biochemical and biophysical research communications》2007,360(2):352-356
Contractility estimation of cardiac myocyte is important for power evaluation of the cell in heart performance. In this paper, we used digital image correlation (DIC) method to obtain dynamic deformation field of the flexible substrate distributively actuated by single cardiac myocyte, which resulted in the dynamic history of traction forces of the cell during contraction-relaxation cycles. Furthermore, the resultant work and power of the single neonatal cardiac myocyte was evaluated to show the energy characteristics of the cells and the responses to the stiffness variation of the substrate. The method provides a useful tool to study behaviors of the cardiac myocytes interacted with the substrates. 相似文献
77.
在生化实验的基础上提出了血小板在凝血中作用的动力学模型,通过定性分析和数值模拟,得到:系统的启动存在一阈值,该阈值与血小板和凝血因子作用的吸附解离常数有密切的关系,即与血小板的存在与否直接相关;血小板的激活比率对系统的正平衡点的稳定性有重要的影响,与凝血启动后的最终状态有关;当刺激强度较小时,因子Ⅷ和Ⅸ对系统的解在定性与定量上没有明显的影响;当刺激强度较大时,因子Ⅷ和Ⅸ在凝血瀑布机制中起级联放大作 相似文献
78.
79.
目的:研究人工髋关节置换术中股骨假体周围骨折的影响因素及其相关性,为人工髋关节置换术中股骨假体周围骨折的预防和诊治提供科学依据。方法:选取本院2012年11月至2013年9月施行髋关节置换手术的患者780例,搜集各研究对象的一般资料(年龄、性别等)以及随访观察其髋关节置换手术后股骨假体周围骨折的发生情况,把股骨假体周围骨折的发生情况与性别、年龄、固定类型等因素进行Logistic回归分析。结果:780例施行髋关节置换手术的患者中,有52例患者术后出现股骨假体周围骨折,总发生率为6.7%;其中A型31例,B型18例(B1型6例,B2型7例,B3型5例),C型3例。女性的发生率(8.5%)高于男性(4.7%),老年患者中股骨假体周围骨折的发生率最高(10.1%),生物型假体固定者的发生率(8.7%)高于骨水泥型假体固定者(3.8%),人工髋关节翻修术中股骨假体周围骨折的发生率最高(11.4%),股骨假体周围骨折发生的危险因素为女性、高龄、使用生物型假体固定,OR值分别为5.301、3.675和2.336。结论:人工髋关节置换术中的危险因素为女性、高龄、使用生物型假体固定,临床医生应在术前对行人工髋关节置换术手术者进行充分的评估,制定合理的手术方案及选择合适的固定方式。 相似文献
80.
Interaction between single molecules of Mac-1 and ICAM-1 in living cells: an atomic force microscopy study 总被引:5,自引:1,他引:5
The interaction between integrin macrophage differentiation antigen associated with complement three receptor function (Mac-1) and intercellular adhesion molecule-1 (ICAM-1), which is controlled tightly by the ligand-binding activity of Mac-1, is central to the regulation of neutrophil adhesion in host defense. Several "inside-out" signals and extracellular metal ions or antibodies have been found to activate Mac-1, resulting in an increased adhesiveness of Mac-1 to its ligands. However, the molecular basis for Mac-1 activation is not well understood yet. In this work, we have carried out a single-molecule study of Mac-1/ICAM-1 interaction force in living cells by atomic force microscopy (AFM). Our results showed that the binding probability and adhesion force of Mac-1 with ICAM-1 increased upon Mac-1 activation. Moreover, by comparing the dynamic force spectra of different Mac-1 mutants, we expected that Mac-1 activation is governed by the downward movement of its alpha7 helix. 相似文献