Mitochondria and Heart Disease

Mitochondria play a key role in the normal functioning of the heart and in the pathogenesis and development of various types of heart disease. In addition, specific mitochondrial cardiomyopathies due to mutations in mitochondrial DNA have been identified. Increasing studies demonstrate that mitochondrial function has emerged as a therapeutic target in heart disease. This chapter addresses the recent studies of the role and the mechanism of mitochondria in the development of heart disease, and the progress in clinical diagnosis and treatments on a mitochondrial basis. Consequently, the aim of this chapter is to outline current knowledge about mitochondria in the heart disease

CG-DIQA: No-reference Document Image Quality Assessment Based on Character Gradient

Document image quality assessment (DIQA) is an important and challenging problem in real applications. In order to predict the quality scores of document images, this paper proposes a novel no-reference DIQA method based on character gradient, where the OCR accuracy is used as a ground-truth quality metric. Character gradient is computed on character patches detected with the maximally stable extremal regions (MSER) based method. Character patches are essentially significant to character recognition and therefore suitable for use in estimating document image quality. Experiments on a benchmark dataset show that the proposed method outperforms the state-of-the-art methods in estimating the quality score of document images.Comment: To be published in Proc. of ICPR 201

Heterogeneous data fusion for three-dimensional gait analysis using wearable MARG sensors

Gait analysis has become a research highlight. In this paper, we propose a computing method using wearable magnetic angular rate and gravity (MARG) sensor arrays with wireless network, which calculates absolute and relative orientation and position information of human foot motion during level walking and stair climbing process. Three-dimensional foot orientation and position were estimated by a Kalman-based sensor fusion algorithm and validated by ground truth provided by Vicon system. The repeatability of the alignment procedure and the measurement errors were evaluated on healthy subjects. Experimental results demonstrate that the proposed method has a good performance at both motion patterns. No significant drifts exist in the overall results presented in the paper. The measured and estimated information can be transmitted to remote server through internet. Moreover, this method could be applied to other cyclical activity monitoring

Using Distributed Wearable Sensors to Measure and Evaluate Human Lower Limb Motions

This paper presents a wearable sensor approach to motion measurements of human lower limbs, in which subjects perform specified walking trials at self-administered speeds so that their level walking and stair ascent capacity can be effectively evaluated. After an initial sensor alignment with the reduced error, quaternion is used to represent 3-D orientation and an optimized gradient descent algorithm is deployed to calculate the quaternion derivative. Sensors on the shank offer additional information to accurately determine the instances of both swing and stance phases. The Denavit-Hartenberg convention is used to set up the kinematic chains when the foot stays stationary on the ground, producing state constraints to minimize the estimation error of knee position. The reliability of this system, from the measurement point of view, has been validated by means of the results obtained from a commercial motion tracking system, namely, Vicon, on healthy subjects. The step size error and the position estimation accuracy change are studied. The experimental results demonstrated that the extensively existed sensor misplacement and sensor drift problems can be well solved. The proposed self-contained and environment-independent system is capable of providing consistent tracking of human lower limbs without significant drift

Vascular Smooth Muscle Cell

Vascular smooth muscle cells (VSMCs) are the stromal cells of the vascular wall and are responsible for regulating arterial tone, blood pressure, and blood supply of the tissues. VSMCs display diversity in function and phenotype depending on their location within the arterial tree (large conduit vs. small resistance vessels), their embryologic origin, and their organ-dependent microenvironment. The heterogeneity of VSMCs is regulated by multiple mechanisms including intracellular signaling and changes in the VSMC microenvironment. Genetic disorders and extrinsic stimuli-induced dysfunction in VSMCs are associated with age-related vascular pathogenesis and vascular diseases, and thus are considered as a potential therapeutic target

Applications of MEMS Gyroscope for Human Gait Analysis

After decades of development, quantitative instruments for human gait analysis have become an important tool for revealing underlying pathologies manifested by gait abnormalities. However, the gold standard instruments (e.g., optical motion capture systems) are commonly expensive and complex while needing expert operation and maintenance and thereby be limited to a small number of specialized gait laboratories. Therefore, in current clinical settings, gait analysis still mainly relies on visual observation and assessment. Due to recent developments in microelectromechanical systems (MEMS) technology, the cost and size of gyroscopes are decreasing, while the accuracy is being improved, which provides an effective way for qualifying gait features. This chapter aims to give a close examination of human gait patterns (normal and abnormal) using gyroscope-based wearable technology. Both healthy subjects and hemiparesis patients participated in the experiment, and experimental results show that foot-mounted gyroscopes could assess gait abnormalities in both temporal and spatial domains. Gait analysis systems constructed of wearable gyroscopes can be more easily used in both clinical and home environments than their gold standard counterparts, which have few requirements for operation, maintenance, and working environment, thereby suggesting a promising future for gait analysis

Role of Macrophages in Early Host Resistance to Respiratory Acinetobacter baumannii Infection

Acinetobacter baumannii is an emerging bacterial pathogen that causes nosocomial pneumonia and other infections. Although it is recognized as an increasing threat to immunocompromised patients, the mechanism of host defense against A. baumannii infection remains poorly understood. In this study, we examined the potential role of macrophages in host defense against A. baumannii infection using in vitro macrophage culture and the mouse model of intranasal (i.n.) infection. Large numbers of A. baumannii were taken up by alveolar macrophages in vivo as early as 4 h after i.n. inoculation. By 24 h, the infection induced significant recruitment and activation (enhanced expression of CD80, CD86 and MHC-II) of macrophages into bronchoalveolar spaces. In vitro cell culture studies showed that A. baumannii were phagocytosed by J774A.1 (J774) macrophage-like cells within 10 minutes of co-incubation, and this uptake was microfilament- and microtubule-dependent. Moreover, the viability of phagocytosed bacteria dropped significantly between 24 and 48 h after co-incubation. Infection of J774 cells by A. baumannii resulted in the production of large amounts of proinflammatory cytokines and chemokines, and moderate amounts of nitric oxide (NO). Prior treatment of J774 cells with NO inhibitors significantly suppressed their bactericidal efficacy (P<0.05). Most importantly, in vivo depletion of alveolar macrophages significantly enhanced the susceptibility of mice to i.n. A. baumannii challenge (P<0.01). These results indicate that macrophages may play an important role in early host defense against A. baumannii infection through the efficient phagocytosis and killing of A. baumannii to limit initial pathogen replication and the secretion of proinflammatory cytokines and chemokines for the rapid recruitment of other innate immune cells such as neutrophils