47 research outputs found

    The Roles of Standardization, Certification and Assurance Services in Global Commerce

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    In this article we examine the rapid emergence and expansion of standardized product and process frameworks and a private-sector compliance and enforcement infrastructure that we believe may increasingly be providing a substitute for public and legal regulatory infrastructure in global commerce. This infrastructure is provided by a proliferation of performance codes and standards, many of which define acceptable social and environmental behavior, and a rapidly-growing number of privately-trained and authorized inspectors and certifiers that we call the third-party assurance industry. We offer reasons for this development, evidence of its scope and scale, and then describe the phenomenon in more detail by examining supply chain arrangements in two industries, food products and apparel, where the use of third-party standards and assurance services has expanded especially rapidly. We conclude with a discussion of the implications for the make or buy decision at the core of the theory of the firm. We argue that as quasi-regulatory standards are developed within various industries, and as performance to these standards can be systematically evaluated using third-party inspectors and certifiers, the costs of moving production outside of vertical firm hierarchies drop. We believe this may be an important factor in accelerating the shift to outsourcing that has been observed over the last two decades

    The role of the peripheral and central nervous systems in rotator cuff disease

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    Rotator cuff (RC) disease is an extremely common condition associated with shoulder pain, reduced functional capacities and impaired quality of life. It primarily involves alterations in tendon health and mechanical properties that can ultimately lead to tendon failure. RC tendon tears induce progressive muscular changes that negatively impact surgical reparability of the RC tendons and clinical outcomes. At the same time, a significant base of clinical data suggests a relatively weak relationship between RC integrity and clinical presentation, emphasizing the multifactorial aspects of RC disease. This review aims to summarize the potential contribution of peripheral, spinal and supraspinal neural factors that may: (i) exacerbate structural and functional muscle changes induced by tendon tear, (ii) compromise the reversal of these changes during surgery and rehabilitation, (iii) contribute to pain generation and persistence of pain, iv) impair shoulder function through reduced proprioception, kinematics and muscle recruitment, and iv) help to explain interindividual differences and response to treatment. Given the current clinical and scientific interest in peripheral nerve injury in the context of RC disease and surgery, we carefully reviewed this body of literature with a particular emphasis for suprascapular neuropathy that has generated a large number of studies in the past decade. Within this process, we highlight the gaps in current knowledge and suggest research avenues for scientists and clinicians

    Static posterior humeral head subluxation and total shoulder arthroplasty

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    BACKGROUND: Static posterior subluxation of the humeral head (PSH) is often associated with glenohumeral arthritis. It may persist following total shoulder arthroplasty (TSA) and lead to accelerated polyethylene wear and glenoid component loosening. The factors which lead to PSH are poorly understood. The purpose of this study was to test the hypothesis that operative correction of glenoid version during shoulder arthroplasty re-centers the glenohumeral joint; therefore, glenoid replacement may be considered even in cases of osteoarthritis associated with posterior humeral head subluxation. METHODS: Thirty-three of 124 (27%) consecutive shoulders undergoing primary TSA had static preoperative PSH with a subluxation index of at least 65% determined on standardized computer tomographic scans. Twenty-three of these 33 shoulders were available for clinical and computed tomography follow-up after a minimum of 24 and average of 42 months. Mean preoperative glenoid retroversion was -18 [range, 0 degrees - (-40 degrees)], the subluxation index averaged 71% (range, 65-81%). Glenoid morphology, according to Walch et al, was type B1 in 9 patients, type B2 in 5 patients, and type C in 9 patients. A conventional total shoulder replacement was performed through a deltopectoral interval. Using corrective glenoid reaming, restoration of glenoid version to between 0 degrees and 10 degrees of retroversion was attempted in addition to standard soft tissue release. Humeral head retroversion was replicated from the diseased humeral head as closely as possible. RESULTS: PSH was reversed in 21/23 patients following TSA with an average final subluxation index of 50% (range, 40-68%; P = .001). There was no significant correlation statistically between PSH and preoperative or postoperative glenoid version, humeral torsion, glenoid morphology, or acromio-humeral distance. Mean absolute Constant scores improved from 39 to 78 points, age-adjusted Constant scores improved from 49% to 95% and subjective shoulder values improved from 40% to 89%, which were all statistically significant (P < .0001). CONCLUSION: PSH is frequently present in shoulders with osteoarthritis. It can be corrected in the majority of shoulders undergoing total shoulder replacement; however, re-centering is not correlated with glenoid version or its correction. LEVEL OF EVIDENCE: Level 4; Case series, treatment study

    Total shoulder arthroplasty with an uncemented soft-metal-backed glenoid component

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    BACKGROUND: Loosening associated with cemented polyethylene glenoid components is a major concern following total shoulder arthroplasty (TSA). The purpose of this study was to investigate the clinical and radiographic results associated with use of a novel uncemented soft-metal-backed glenoid component (SMBG), with a minimum follow-up of 2 years. MATERIALS AND METHODS: Twenty-two patients (19 women) underwent TSA using a uncemented SMBG. The mean age was 68.5 years (range, 49-84). Mean follow-up was 50 months (range, 24-89). Indications for TSA were primary osteoarthritis (10), post-traumatic osteoarthritis (8), steroid-induced avascular necrosis (2), crystalline arthropathy (1), and arthritis secondary to systemic lupus erythematodes (1). Subjective and objective parameters were assessed. Loosening and polyethylene wear were evaluated. RESULTS: Mean absolute Constant scores improved from 29.1 to 65.9 points (P < .001), age- and sex-adjusted Constant scores improved from 40.1 to 87.7% (P < .001), and subjective shoulder values improved from 35% to 75.2% (P < .001). Mean pain scores improved from 4.2 points to 13.1 (P < .001). Three cases had a fractured glenoid component. Only these 3 had a definite loosening. Polyethylene wear was found in 2 cases. CONCLUSION: Use of an uncemented SMBG component yields controversial results. Osteointegration appears possible and loosening signs have virtually not been observed. Conversely, the current implant can be associated with a high failure rate (13.6%) because of implant fractures despite short follow-up. As loosening seems absent or minimal but implant stability insufficient, design changes need to be performed and tested in view of solving the implant failure problem while preserving the actually excellent bone-implant interface characteristics

    Early genetic mechanisms underlying the inhibitory effects of endostatin and fumagillin on human endothelial cells

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    A tumor needs to initiate angiogenesis in order to develop its own blood supply, to grow, to invade, and to spread. Angiogenesis, under normal conditions, is a tightly regulated balance between endogenous pro- and antiangiogenic factors. In this study, we investigated, by microarray analysis, the effects of two known antiangiogenic agents (endostatin and fumagillin) on the gene expression profiles of human umbilical vein endothelial cells (HUVEC) in order to elucidate pathways common to the effects of these agents. We observed a majority of gene expression changes within 1 and 2 h of treatment. The genes demonstrating these early expression changes are involved in cell proliferation, gene transcription, and a number have unknown functions. We selected four genes (DOC1, KLF4, TC-1, ID1) from the microarray profile that showed a similar pattern of expression for both of the antiangiogenic agents we tested. We then used small interfering RNAs (siRNA) in an attempt to better understand the role of these selected genes in the inhibitory activity of these agents. Because the gene expression changes occurred within 1 and 2 h of treatment, these genes might be involved in the initial pathways of angiogenesis inhibition

    Microarray Gene Expression Analysis of Murine Tumor Heterogeneity Defined by Dynamic Contrast-Enhanced MRI

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    Current methods of studying angiogenesis are limited in their ability to serially evaluate in vivo function throughout a target tissue. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and pharmacokinetic modeling provide a useful method for evaluating tissue vasculature based on contrast accumulation and washout. While it is often assumed that areas of high contrast enhancement and washout comprise areas of increased angiogenesis and tumor activity, the actual molecular pathways that are active in such areas are poorly understood. Using DCE-MRI in a murine subcutaneous tumor model, we were able to perform pharmacokinetic functional analysis of a tumor, coregistration of MRI images with histological cross-sections, immunohistochemistry, laser capture microdissection, and genetic profiling of tumor heterogeneity based on pharmacokinetic parameters. Using imaging as a template for biologic investigation, we have not found evidence of increased expression of proangiogenic modulators at the transcriptional level in either distinct pharmacokinetic region. Furthermore, these regions show no difference on histology and CD31 immunohistochemistry. However, the expression of ribosomal proteins was greatly increased in high enhancement and washout regions, implying increased protein translation and consequent increased cellular activity. Together, these findings point to the potential importance of posttranscriptional regulation in angiogenesis and the need for the development of angiogenesis-specific contrast agents to evaluate in vivo angiogenesis at a molecular level
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