No evidence for collateral effects of electromagnetic fields used to increase dissolved oxygen levels on the behavior and physiology of freshwater fishes.

Hypoxia in surface waters driven by warming climate and other anthropogenic stressors is a major conservation concern, and technological solutions for water quality remediation are sorely needed. One potential solution involves the use of low-intensity electromagnetic fields (EMFs) to increase dissolved oxygen levels, but potential collateral effects of the EMFs on aquatic animals have not been formally evaluated. We examined the effects of EMF exposure on wild-caught, captive sunfish (Lepomis spp.

Advances in the development of gene therapy, noncoding RNA, and exosome-based treatments for tendinopathy.

Tendinopathy is a common musculoskeletal disorder characterized by chronic low-grade inflammation and tissue degeneration. Tendons have poor innate healing ability and there is currently no cure for tendinopathy. Studies elucidating mechanisms underlying the pathogenesis of tendinopathy and mechanisms mediating the genesis of tendons during development have provided novel targets and strategies to enhance tendon healing and repair.

Cycle-dependent matrix remodeling gene expression response in fatigue-loaded rat patellar tendons.

Expression profiling of selected matrix remodeling genes was conducted to evaluate differences in molecular response to low-cycle (100) and high-cycle (7,200) sub-failure-fatigue loading of patellar tendons. Using our previously developed in vivo patellar tendon model, tendons were loaded for 100 or 7,200 cycles and expression of selected metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and collagens were quantified by real-time RT-PCR at 1- and 7-day post-loading. Expression profiles were also obtained from lacerated tendons as an acute injury model.

A knee-specific finite element analysis of the human anterior cruciate ligament impingement against the femoral intercondylar notch.

This work presents a finite element analysis of anterior cruciate ligament (ACL) impingement against the intercondylar notch during tibial external rotation and abduction, as a mechanism of noncontact ACL injuries. Experimentally, ACL impingement was measured in a cadaveric knee in terms of impingement contact pressure and six degrees-of-freedom tibiofemoral kinematics. Three-dimensional geometries of the ACL, femur and tibia were incorporated into the finite element model of the individual knee specimen.

Second harmonic generation imaging and Fourier transform spectral analysis reveal damage in fatigue-loaded tendons.

Conventional histologic methods provide valuable information regarding the physical nature of damage in fatigue-loaded tendons, limited to thin, two-dimensional sections. We introduce an imaging method that characterizes tendon microstructure three-dimensionally and develop quantitative, spatial measures of damage formation within tendons. Rat patellar tendons were fatigue loaded in vivo to low, moderate, and high damage levels.

Early response to tendon fatigue damage accumulation in a novel in vivo model.

This study describes the development and application of a novel rat patellar tendon model of mechanical fatigue for investigating the early in vivo response to tendon subfailure injury. Patellar tendons of adult female Sprague-Dawley rats were fatigue loaded between 1-35N using a custom-designed loading apparatus. Patellar tendons were subjected to Low-, Moderate- or High-level fatigue damage, defined by grip-to-grip strain measurement.

Subrupture tendon fatigue damage.

The mechanical and microstructural bases of tendon fatigue, by which damage accumulates and contributes to degradation, are poorly understood. To investigate the tendon fatigue process, rat flexor digitorum longus tendons were cyclically loaded (1-16 N) until reaching one of three levels of fatigue damage, defined as peak clamp-to-clamp strain magnitudes representing key intervals in the fatigue life: i) Low (6.0%-7.

Coordinate regulation of IL-1beta and MMP-13 in rat tendons following subrupture fatigue damage.

Mechanical overloading is a major causative factor of tendinopathy; however, its underlying mechanisms are unclear. We hypothesized mechanical overloading would damage tendons and alter genes associated with tendinopathy in a load-dependent manner. To test this hypothesis, we fatigue loaded rat patellar tendons in vivo and measured expression of the matrix-degrading enzyme MMP-13 and the inflammatory cytokine IL-1beta.

ACL impingement prediction based on MRI scans of individual knees.

Although tibial external rotation and abduction do not load the ACL strongly in cadaver-based biomechanical studies, such knee positions are associated with ACL injuries in clinical practice. We hypothesized the ACL could be injured in such knee positions because of its impingement against the intercondylar notch. We developed a three-dimensional geometric ACL impingement model through segmentation of MR images of individual knees.

Modeling of ACL impingement against the intercondylar notch.

Objective: To develop a 3-D mathematical model that accurately evaluates anterior cruciate ligament impingement against the intercondylar notch.

Design: The model simulated physical interactions between the anterior cruciate ligament and the intercondylar notch in tibiofemoral movement.

Background: Anterior cruciate ligament impingement has been evaluated through planar radiographic images, which may not characterize the complex 3-D notch shape associated with impingement.