Citations

Many neck pain complaints are associated with degenerated discs in cervical spine. Disc degeneration (DD) consists of cascading stages of events with complex changes in disc tissue properties. This results in deterioration of the ability of the disc to perform its function normally. Several biomechanical and biochemical changes occur in the disc with degeneration. Increase in motion segment stiffness and peak stresses in the posterior annulus are some of the gross changes that occur in the disc with degeneration.

Meniscal attachments serve to anchor and transfer loads from menisci to the tibia. These ligamentous tissues are composed of collagen fibers, elastin, ground substance and water. Ligaments have a time- and history-dependent viscoelastic behavior due in part to the interaction of the water and the ground substance [1]. The movement of water within ligamentous tissue is limited because of charged proteoglycan molecules. It has been shown that some exudation of water is present during cyclic loading of ligamentous tissue [2]. The movement and its inhibition could lead to changes of pressure within the meniscal attachments. Therefore, the purpose of this study was to quantify the internal pressure in human meniscal attachments subjected to physiological loading. Since it is thought that the posterior attachment is subjected to both tension and compression, while the anterior attachment is primarily subjected to tension [3–5], we hypothesized that the attachments mechanical environment is dictated by the external loads, and hence, the posterior attachment would elicit higher pressures.

ABSTRACTGene‐gene interactions are increasingly being addressed as a potentially important contributor to the variability of complex traits. Consequently, attentions have moved beyond single locus analysis of association to more complex genetic models. Although several single‐marker approaches toward interaction analysis have been developed, such methods suffer from very high testing dimensionality and do not take advantage of existing information, notably the definition of genes as functional units. Here, we propose a comprehensive family of gene‐level score tests for identifying genetic elements of disease risk, in particular pairwise gene‐gene interactions. Using kernel machine methods, we devise score‐based variance component tests under a generalized linear mixed model framework. We conducted simulations based upon coalescent genetic models to evaluate the performance of our approach under a variety of disease models. These simulations indicate that our methods are generally higher powered than alternative gene‐level approaches and at worst competitive with exhaustive SNP‐level (where SNP is single‐nucleotide polymorphism) analyses. Furthermore, we observe that simulated epistatic effects resulted in significant marginal testing results for the involved genes regardless of whether or not true main effects were present. We detail the benefits of our methods and discuss potential genome‐wide analysis strategies for gene‐gene interaction analysis in a case‐control study design.

ABSTRACTIntroduction: Mitochondrial trifunctional protein deficiency is a rare autosomal recessive disorder of mitochondrial fatty acid β‐oxidation that may be due to mutations in 2 different nuclear genes, HADHA and HADHB. Perturbation of this multienzyme complex compromises the oxidation of long‐chain fatty acids, which leads to multiorgan dysfunction. Childhood‐ or adolescent‐onset recurrent rhabdomyolysis is a common muscular manifestation and is preceded frequently by clinically overt peripheral neuropathy. Methods: In this report we describe a patient with late adult‐onset recurrent rhabdomyolysis. Results: Despite normal sensory examination, nerve conduction studies showed a mild axonal peripheral neuropathy. The acylcarnitine profile showed elevated long‐chain and 3‐hydroxy long‐chain acylcarnitine species. HADHA sequencing revealed known compound heterozygous mutations c.180+3A>G (p.Thr37SerfsX6) and c.1528G>C (p.Glu510Gln). During a 10‐month follow‐up period, he had no further episodes of rhabdomyolysis after appropriate dietary modifications. Conclusions: Mitochondrial trifunctional protein deficiency should be considered in patients with adult‐onset recurrent rhabdomyolysis, especially in those with either clinically overt or subclinical peripheral neuropathy. Muscle Nerve 48: 989–991, 2013

ABSTRACTIntroduction: Needle electromyography (EMG) of the diaphragm carries the potential risk of pneumothorax. Knowing the approximate depth of the diaphragm should increase the test's safety and accuracy. Methods: Distances from the skin to the diaphragm and from the outer surface of the rib to the diaphragm were measured using B mode ultrasound in 150 normal subjects. Results: When measured at the lower intercostal spaces, diaphragm depth varied between 0.78 and 4.91 cm beneath the skin surface and between 0.25 and 1.48 cm below the outer surface of the rib. Using linear regression modeling, body mass index (BMI) could be used to predict diaphragm depth from the skin to within an average of 1.15 mm. Conclusions: Diaphragm depth from the skin can vary by more than 4 cm. When image guidance is not available to enhance accuracy and safety of diaphragm EMG, it is possible to reliably predict the depth of the diaphragm based on BMI. Muscle Nerve 49: 666–668, 2014

Object The authors' objective was 2-fold: 1) to compare outcomes of microsurgical resection for vestibular schwannoma (VS) between patients aged 70 years or older and patients younger than 70 years and 2) to test the hypothesis that symptomatic tumors in elderly patients represent a more aggressive variant of VS than those in younger adults, resulting in increased morbidity and a higher rate of recurrence after subtotal resection (STR). Methods A retrospective matched cohort study was conducted. Patients aged 70 years or older who had undergone microsurgical resection of VS were matched to adult patients younger than 70 years; the matching was performed on the basis of surgical approach, completeness of resection, and tumor size. Associations between clinical, radiographic, and surgical data and postoperative outcome were analyzed using conditional logistic regression. Results Twenty patients aged 70 years or older (mean age ± SD 75.9 ± 5.3, range 70–86 years) were identified and matched to a cohort of younger adult patients (mean age ± SD 55.7 ± 13.8, range 25–69 years). The mean tumor size in both groups was approximately 3 cm. Overall, the elderly patients had a poorer preoperative American Society of Anesthesiology physical status score (p = 0.038), were more likely to report imbalance (OR 9.61, p = 0.016), and more commonly exhibited compromised balance and coordination (OR 9.61, p = 0.016) than patients in the younger cohort. There were no differences between the 2 cohorts in perioperative complications (p = 0.26) or facial nerve function (p > 0.5) at any time. The elderly patients were 13 times more likely to have long-term postoperative imbalance (OR 13.00, p = 0.013) than the younger patients. Overall, 9 tumors recurred among 32 patients undergoing STR; 6 of these patients underwent additional interventions (stereotactic radiosurgery in 5 patients and microsurgery in 1) and showed no evidence of tumor progression at the last follow-up. The median growth rate of the recurrent tumor in the 6 elderly patients was 4.8 mm/year (range 2.1–14.9 mm/year) and, in the 3 control patients, 2.2 mm/year (range 1.9–4.0 mm/year). Overall, the mortality data showed a trend toward statistical significance (p = 0.068) with a higher risk of death in the elderly. Conclusions As the number of elderly patients with VS increases, microsurgical resection will remain an important management option for these patients. Despite a poorer preoperative physical status in elderly patients, their morbidity profiles are similar to those in adult patients younger than 70 years. However, elderly patients may require longer convalescence due to prolonged postoperative imbalance. Not surprisingly, overall diminished functional reserve and advanced comorbidities may increase the mortality risk associated with surgical intervention in the elderly patients. Finally, there was a high risk of further tumor growth following STR in the elderly patients (6 [37.5%] of 16), underscoring the need for close postoperative radiological surveillance and consideration of early stereotactic radiosurgery for the tumor remnant following the STR.

The American Society for Apheresis (ASFA) JCA Special Issue Writing Committee is charged with reviewing, updating and categorizating indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence‐based approach in the grading and categorization of indications. This Sixth Edition of the ASFA Special Issue has further improved the process of using evidence‐based medicine in the recommendations by consistently applying the category and GRADE system definitions, but eliminating the “level of evidence” criteria (from the University HealthCare Consortium) utilized in prior editions given redundancy between GRADE and University HealthCare Consortium systems. The general layout and concept of a fact sheet that was utilized in the Fourth and Fifth Editions, has been largely maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. This article consists of 78 fact sheets (increased from 2010) for therapeutic indications in ASFA categories I through IV, with many diseases categorized having multiple clinical presentations/situations which are individually graded and categorized. J. Clin. Apheresis 28:145–284, 2013. © 2013 Wiley Periodicals, Inc.