Comprehensive Mutation Analysis for Congenital Muscular Dystrophy: A Clinical PCR-Based Enrichment and Next-Generation Sequencing Panel

The congenital muscular dystrophies (CMDs) comprise a heterogeneous group of heritable muscle disorders with often difficult to interpret muscle pathology, making them challenging to diagnose. Serial Sanger sequencing of suspected CMD genes, while the current molecular diagnostic method of choice, can be slow and expensive. A comprehensive panel test for simultaneous screening of mutations in all known CMD-associated genes would be a more effective diagnostic strategy. Thus, the CMDs are a model disorder group for development and validation of next-generation sequencing (NGS) strategies for diagnostic and clinical care applications. Using a highly multiplexed PCR-based target enrichment method (RainDance) in conjunction with NGS, we performed mutation detection in all CMD genes of 26 samples and compared the results with Sanger sequencing. The RainDance NGS panel showed great consistency in coverage depth, on-target efficiency, versatility of mutation detection, and genotype concordance with Sanger sequencing, demonstrating the test''s appropriateness for clinical use. Compared to single tests, a higher diagnostic yield was observed by panel implementation. The panel''s limitation is the amplification failure of select gene-specific exons which require Sanger sequencing for test completion. Successful validation and application of the CMD NGS panel to improve the diagnostic yield in a clinical laboratory was shown.     

Endothelial progenitor cells in cardiovascular diseases

Endothelial dysfunction has been associated with the development of atherosclerosis and cardiovascular diseases. Adult endothelial progenitor cells(EPCs) are derived from hematopoietic stem cells and are capable of forming new blood vessels through a process of vas-culogenesis. There are studies which report correlations between circulating EPCs and cardiovascular risk fac-tors. There are also studies on how pharmacotherapies may influence levels of circulating EPCs. In this review, we discuss the potential role of endothelial progenitor cells as both diagnostic and prognostic biomarkers. In addition, we look at the interaction between cardio-vascular pharmacotherapies and endothelial progenitor cells. We also discuss how EPCs can be used directly and indirectly as a therapeutic agent. Finally, we evalu-ate the challenges facing EPC research and how these may be overcome.     

An integrated approach in the discovery and characterization of a novel nuclear protein over-expressed in liver and pancreatic tumors

An integrated approach in protein discovery through the use of multidisciplinary tools was reported. A novel protein, Hcc-1, was identified by analysis of the hepatocellular carcinoma (HCC)-M cell proteome. The assembled EST sequence of the 210 amino acid novel protein was subsequently confirmed by rapid amplification of cDNA ends (RACE). A total of 687 bp at the 5' untranslated region of Hcc-1 was identified. Promoter activity and several upstream open reading frames (uORFs) were demonstrated at this region. Bioinformatics prediction showed that the first 42 amino acids of the protein is a SAP domain with sequence matches to hnRNP from various vertebrate species. The Hcc-1 protein was localized to the cell nucleus while the gene was localized to chromosome 7q22.1. Hcc-1 cDNA level was increased in pancreatic adenocarcinoma. The level was also increased in well-differentiated hepatocellular carcinoma but decreases as the carcinoma progressed to a poorly differentiated stage.     

Isolation of the gene coding for Caenorhabditis elegans Rac2 homologue, a Ras-related small GTP-binding protein

When screening a Caenorhabditis elegans genomic library using the human Racl cDNA as probe, a hybridizing fragment of 2.7 kb was isolated which contained four exons with high sequence similarity to CeRacl, coding for the nematode homologue of the Ras-related small GTP-binding protein Racl. The putative translational product of 195 amino acids (aa) from the exons displayed 88% identity to the sequence of CeRacl. Interestingly, three alterations were found in the N-terminal ‘effector domain’ (residues 22–45) which hitherto was identical among all known Rac p21s, suggesting that CeRac2 might have different targets/functions for nematode development. Additionally, an insertion of 4 as was found in the hypervariable region at the C terminus of CeRac2.     

3D coupling of fibronectin fibril arrangement with topology of ventral plasma membrane

Interaction of integrins with extracellular matrices is essential for cell adhesion to substrata. Ventral surfaces of fibroblasts adhering to flat substrata are not flat but have uneven 3D topology. However, spatial relationship between the topology of the ventral cell surface and arrangement of extracellular matrix fibrils remains unclear. Here, we report a novel and simple method based on total internal reflection fluorescence microscopy to quantify the distance between the ventral plasma membrane and the glass substratum. We observe that the distance varies from < 25 nm at focal adhesions to 40-50 nm at close contacts and > 80 nm in other regions. Furthermore, by applying this novel method, we show that fibronectin fibrils are also separated from the substratum in regions where the ventral cell surface-substratum distance is > 80 nm. Our results reveal that fibronectin fibrils are not simply adsorbed to the glass substratum but follow the ventral cell surface topology.     

Altruism and Reward: Motivational Compatibility in Deceased Organ Donation

Acts of helping others are often based on mixed motivations. Based on this claim, it has been argued that the use of a financial reward to incentivize organ donation is compatible with promoting altruism in organ donation. In its report Human Bodies: Donation for Medicine and Research, the Nuffield Council on Bioethics uses this argument to justify its suggestion to pilot a funeral payment scheme to incentivize people to register for deceased organ donation in the UK. In this article, I cast a sceptical eye on the above Nuffield report's argument that its proposed funeral payment scheme would prompt deceased organ donations that remain altruistic (as defined by and valued the report). Specifically, I illustrate how this scheme may prompt various forms of mixed motivations which would not satisfy the report's definition of altruism. Insofar as the scheme produces an expectation of the reward, it stands diametrical to promoting an ‘altruistic perspective’. My minimal goal in this article is to argue that altruism is not motivationally compatible with reward as an incentive for donation. My broader goal is to argue that if a financial reward is used to incentivize organ donation, then we should recognize that the donation system is no longer aiming to promote altruism. Rewarded donation would not be altruistic but it may be ethical given a persistent organ shortage situation.     

Cardiotrophin-1 alters airway smooth muscle structure and mechanical properties in airway explants

Induction of hypertrophy and inhibition of apoptosis may be important mechanisms contributing to increased airway smooth muscle (ASM) mass in asthma. Data from our laboratory indicate that cardiotrophin-1 (CT-1) induces hypertrophy and inhibits apoptosis in isolated human ASM cells. To determine whether these novel effects of CT-1 also occur in the airway tissue milieu and to determine whether structural changes are accompanied by functional changes, matched pairs of guinea pig airway explants were treated with or without CT-1 for 7 days, and structural features as well as isometric and isotonic contractile and relaxant mechanical properties were measured. CT-1 (0.2-5 ng/ml) increased both myocyte mass and extracellular matrix in a concentration-dependent fashion. CT-1 (10 ng/ml)-treated tissues exhibited a significant increase in passive tension at all lengths on day 7; at optimal length, passive tension generated by CT-1-treated tissues was 1.72 +/- 0.12 vs. 1.0 +/- 0.1 g for control. Maximal isometric stress was decreased in the CT-1-treated group on day 7 (0.39 +/- 0.10 kg/cm(2)) vs. control (0.77 +/- 0.15 kg/cm(2), P < 0.05). Isoproterenol-induced relaxant potency was reduced in CT-1-treated tissues, log EC(50) being -7.28 +/- 0.34 vs. -8.12 +/- 0.25 M in control, P < 0.05. These data indicate that CT-1 alters ASM structural and mechanical properties in the tissue environment and suggest that structural changes found in the airway wall in asthma are not necessarily associated with increased responsiveness.     

A proteomic analysis of thioacetamide-induced hepatotoxicity and cirrhosis in rat livers

Thioacetamide (TAA) administration is an established technique for generating rat models of liver fibrosis and cirrhosis. Oxidative stress is believed to be involved as TAA-induced liver fibrosis is initiated by thioacetamide S-oxide, which is derived from the biotransformation of TAA by the microsomal flavine-adenine dinucleotide (FAD)-containing monooxygense (FMO) and cytochrome P450 systems. A two-dimensional gel electrophoresis-mass spectrometry approach was applied to analyze the protein profiles of livers of rats administered with sublethal doses of TAA for 3, 6 and 10 weeks respectively. With this approach, 59 protein spots whose expression levels changed significantly upon TAA administration were identified, including three novel proteins. These proteins were then sorted according to their common biochemical properties and functions, so that pathways involved in the pathogenesis of rat liver fibrosis due to TAA-induced toxicity could be elucidated. As a result, it was found that TAA-administration down-regulated the enzymes of the primary metabolic pathways such as fatty acid beta-oxidation, branched chain amino acids and methionine breakdown. This phenomenon is suggestive of the depletion of succinyl-CoA which affects heme and iron metabolism. Up-regulated proteins, on the other hand, are related to oxidative stress and lipid peroxidation. Finally, these proteomics data and the data obtained from the scientific literature were integrated into an "overview model" for TAA-induced liver cirrhosis. This model could now serve as a useful resource for researchers working in the same area.     

Adaptation to chronic length change in explanted airway smooth muscle.

It has been shown that airway smooth muscle in vitro is able to maintain active force over a large length range by adaptation in the absence of periodic stimulations at 4 degrees C (Wang L, Paré PD, and Seow CY. J Appl Physiol 90: 734-740, 2001). In this study, we show that such adaptation also takes place at body temperature and that long-term adaptation results in irreversible functional change in the muscle that could lead to airway hyperresponsiveness. Rabbit tracheal muscle explants were passively maintained at shortened and in situ length for 3 and 7-8 days in culture media; the length-tension relationship was then examined. The length associated with maximal force generation decreased by 10.5 +/- 3.8% (SE) after 3 days and 37.7 +/- 8.5% after 7 or 8 days of passive shortening. At day 3, the left shift in the length-tension curve due to adaptation at short lengths was reversible by readapting the muscle at a longer length. The shift was, however, not completely reversible after 7 days. The results suggest that long-term adaptation of airway smooth muscle could lead to increased muscle stiffness and force-generating ability at short lengths. Under in vivo condition, this could translate into resistance to stretch-induced relaxation and excessive airway narrowing.     

Mild Joint Symptoms Are Associated with Lower Risk of Falls than Asymptomatic Individuals with Radiological Evidence of Osteoarthritis

Osteoarthritis (OA) exacerbates skeletal muscle functioning, leading to postural instability and increased falls risk. However, the link between impaired physical function, OA and falls have not been elucidated. We investigated the role of impaired physical function as a potential mediator in the association between OA and falls. This study included 389 participants [229 fallers (≥2 falls or one injurious fall in the past 12 months), 160 non-fallers (no history of falls)], age (≥65 years) from a randomized controlled trial, the Malaysian Falls Assessment and Intervention Trial (MyFAIT). Physical function was assessed using Timed Up and Go (TUG) and Functional Reach (FR) tests. Knee and hip OA were diagnosed using three methods: Clinical, Radiological and Self-report. OA symptom severity was assessed using the Western Ontario and McMaster Universities Arthritis Index (WOMAC). The total WOMAC score was categorized to asymptomatic, mild, moderate and severe symptoms. Individuals with radiological OA and ‘mild’ overall symptoms on the WOMAC score had reduced risk of falls compared to asymptomatic OA [OR: 0.402(0.172–0.940), p = 0.042]. Individuals with clinical OA and ‘severe’ overall symptoms had increased risk of falls compared to those with ‘mild’ OA [OR: 4.487(1.883–10.693), p = 0.005]. In individuals with radiological OA, mild symptoms appear protective of falls while those with clinical OA and severe symptoms have increased falls risk compared to those with mild symptoms. Both relationships between OA and falls were not mediated by physical limitations. Larger prospective studies are needed for further evaluation.