Biomechanical analysis of dual versus lateral locked plating in elderly bicondylar tibial plateau fractures: Does medial comminution matter?

Objective: To assess dual plating versus lateral locked plate fixation of bicondylar tibial plateau fractures in an elderly cadaveric model with and without medial bone loss PARTICIPANTS: 10 pairs of elderly (range 78-93 years of age) fresh frozen tibias.

Intervention: Bicondylar tibial plateau fractures were created reproducing AO/OTA 41 C1 (without medial bone loss) and C2 fractures (with medial bone loss). Cadavers were randomized to 4 different groups.

Hybrid screw fixation for femoral neck fractures: Does it prevent mechanical failure?

Introduction: Traditionally, femoral neck fracture fixation has been performed using three partially threaded cancellous screws. However, fracture collapse with femoral neck shortening, and varus deformation frequently occurs due to posterior medial comminution and lack of calcar support. We hypothesize replacing the inferior neck/calcar screw with a fully threaded, length stable, screw will provide improved biomechanical stability, decrease femoral neck shortening and varus collapse.

Urological Emergencies and Diseases in Wilderness Expeditions.

When considering medical emergencies that might affect an expedition, urologic emergencies are typically not included. However, the reality is that manageable and prevalent urologic disease processes can pose significant challenges for the wilderness medicine physician and warrant consideration. The purpose of this review is to identify and discuss the most commonly encountered urologic emergencies and diseases in the wilderness setting and to prepare the expedition medicine physician for management of these urgent conditions.

Biomechanical evaluation of medial malleolus fractures treated with headless compression screws.

Purpose: The gold standard for fixation of medial malleolus fractures has yet to be determined. Most agree the best results of displaced unstable ankle fractures are with open reduction and internal fixation. Hardware irritation necessitating screw removal is a known complication.

Impact of a statewide trauma system on the triage, transfer, and inpatient mortality of injured patients.

Background: In 2009, Arkansas implemented a statewide trauma system to address the high rates of mortality and morbidity due to trauma. The principal objective of the Arkansas Trauma System is to transport patients to the appropriate facility based on the injuries of the patients. This study evaluated four metrics that were crucial to system health.

Kallistatin reduces vascular senescence and aging by regulating microRNA-34a-SIRT1 pathway.

Kallistatin, an endogenous protein, protects against vascular injury by inhibiting oxidative stress and inflammation in hypertensive rats and enhancing the mobility and function of endothelial progenitor cells (EPCs). We aimed to determine the role and mechanism of kallistatin in vascular senescence and aging using cultured EPCs, streptozotocin (STZ)-induced diabetic mice, and Caenorhabditis elegans (C. elegans).

Protective Role of Kallistatin in Vascular and Organ Injury.

Kallistatin is an endogenous protein that exerts pleiotropic effects, including vasodilation and inhibition of angiogenesis, inflammation, oxidative stress, apoptosis, fibrosis, and tumor progression. Through its two functional domains – an active site and a heparin-binding site – kallistatin regulates differential signaling pathways and a wide spectrum of biological functions. Kallistatin's active site is key for inhibiting tissue kallikrein activity, and stimulating the expression of endothelial nitric oxide synthase (eNOS), sirtuin 1 (SIRT1) and suppressor of cytokine signaling 3 (SOCS3).

Nonanatomic Tibial Tunnel Placement for Single-Bundle Posterior Cruciate Ligament Reconstruction Leads to Greater Posterior Tibial Translation in a Biomechanical Model.

Purpose: To determine the effect of varying proximal-distal tibial tunnel placement on posterior cruciate ligament (PCL) laxity.

Methods: Nine matched pairs (18 total) of cadaveric knees (mean age 79.3 years, range 60 to 89), were studied.

Biomechanical Contribution of Tension-Reducing Rotator Cuff Sutures in 3-Part Proximal Humerus Fractures.

Objectives: Using a cadaveric 3-part fracture model and cyclic loading protocol, our study objectives were to quantify the stabilizing effect of tension-reducing rotator cuff sutures in terms of fracture displacement across the surgical neck and greater tuberosity compared with a control group in which no sutures were used.

Methods: Six matched pairs of fresh frozen specimens underwent a standardized, 3-part, proximal humerus fracture and were split into 2 groups. The control group had the fracture fixed with a plate and screw construct only while the experimental group had additional suture fixation through the plate to each rotator cuff tendon.

Kallistatin induces breast cancer cell apoptosis and autophagy by modulating Wnt signaling and microRNA synthesis.

Kallistatin is an endogenous protein that regulates differential signaling pathways and biological functions. Our previous studies showed that kallistatin gene therapy inhibited angiogenesis, tumor growth and metastasis in mice, and kallistatin protein suppressed Wnt-mediated growth, migration and invasion by blocking Wnt/β-catenin signaling pathway in breast cancer cells. In this study, we show that kallistatin reduced cell viability, and increased apoptotic cell death and caspase-3 activity in MDA-MB-231 breast cancer cells.

Anterior Cruciate Ligament Graft Isometry is Affected by the Orientation of the Femoral Tunnel.

Purpose: The purpose of this study was to compare anterior cruciate ligament (ACL) graft length and tension throughout knee range of motion with transtibial, anteromedial (AM) portal, and all-epiphyseal drilling techniques with suspensory and apical femoral fixation.

Methods: The three different femoral tunnel drilling techniques using the same intra-articular starting point within the center of the femoral footprint were performed on fresh-frozen cadaveric specimens. All groups underwent standard tibial drilling in the center of the ACL tibial footprint.

Kallistatin inhibits TGF-β-induced endothelial-mesenchymal transition by differential regulation of microRNA-21 and eNOS expression.

Kallistatin, an endogenous protein, consists of two structural elements: active site and heparin-binding domain. Kallistatin exerts beneficial effects on fibrosis by suppressing transforming growth factor (TGF)-β synthesis in animal models. TGF-β is the most potent inducer of endothelial-mesenchymal transition (EndMT), which contributes to fibrosis and cancer.

Kallistatin treatment attenuates lethality and organ injury in mouse models of established sepsis.

Introduction: Kallistatin levels in the circulation are reduced in patients with sepsis and liver disease. Transgenic mice expressing kallistatin are resistant to lipopolysaccharide (LPS)-induced mortality. Here, we investigated the effect of kallistatin on survival and organ damage in mouse models of established sepsis.

Kallikrein-kinin in stem cell therapy.

The tissue kallikrein-kinin system exerts a wide spectrum of biological activities in the cardiovascular, renal and central nervous systems. Tissue kallikrein-kinin modulates the proliferation, viability, mobility and functional activity of certain stem cell populations, namely mesenchymal stem cells (MSCs), endothelial progenitor cells (EPCs), mononuclear cell subsets and neural stem cells. Stimulation of these stem cells by tissue kallikrein-kinin may lead to protection against renal, cardiovascular and neural damage by inhibiting apoptosis, inflammation, fibrosis and oxidative stress and promoting neovascularization.

Novel role of kallistatin in vascular repair by promoting mobility, viability, and function of endothelial progenitor cells.

Background: Kallistatin exerts pleiotropic activities in inhibiting inflammation, apoptosis, and oxidative stress in endothelial cells. Because endothelial progenitor cells (EPCs) play a significant role in vascular repair, we investigated whether kallistatin contributes to vascular regeneration by enhancing EPC migration and function.

Methods And Results: We examined the effect of endogenous kallistatin on circulating EPCs in a rat model of vascular injury and the mechanisms of kallistatin on EPC mobility and function in vitro.

Tissue kallikrein-kinin therapy in hypertension and organ damage.

Tissue kallikrein is a serine proteinase that cleaves low molecular weight kininogen to produce kinin peptides, which in turn activate kinin receptors to trigger multiple biological functions. In addition to its kinin-releasing activity, tissue kallikrein directly interacts with the kinin B2 receptor, protease-activated receptor-1, and gamma-epithelial Na channel. The tissue kallikrein-kinin system (KKS) elicits a wide spectrum of biological activities, including reducing hypertension, cardiac and renal damage, restenosis, ischemic stroke, and skin wound injury.

No Contribution of Tension-Reducing Rotator Cuff Sutures on Locking Plate Fixation in a 2-Part Proximal Humerus Fracture Model.

Objectives: Varus failure is a well-known complication of open reduction internal fixation of proximal humeral fractures. The addition of tension-reducing sutures from the plate to the rotator cuff may attenuate the deforming forces of the rotator cuff resulting in decreased varus failure. In this study, we investigate the biomechanical contributions of tension-reducing sutures to a locked plate construct in a 2-part proximal humerus fracture model.

Biomechanical comparison of long head of biceps tenodesis with interference screw and biceps sling soft tissue techniques.

Purpose: The purpose of our study was to compare biomechanically a long head biceps tenodesis using an all soft tissue biceps sling technique versus an interference screw technique.

Methods: Six paired fresh frozen shoulder specimens were separated into 2 groups. One group used an all soft tissue biceps sling technique for tenodesis.

Tissue kallikrein-modified mesenchymal stem cells provide enhanced protection against ischemic cardiac injury after myocardial infarction.

Background: Genetically modified mesenchymal stem cells (MSCs) are a promising approach to the treatment of cardiac injury after myocardial infarction (MI).

Methods And Results: Rat MSCs were transduced with adenovirus containing human tissue kallikrein (TK) gene (TK-MSCs), and they secreted human TK into culture medium. Cultured TK-MSCs were more resistant to hypoxia-induced apoptosis and exhibited reduced caspase-3 activity compared to control GFP-MSCs.

Kallistatin antagonizes Wnt/β-catenin signaling and cancer cell motility via binding to low-density lipoprotein receptor-related protein 6.

Kallistatin, a plasma protein, exerts pleiotropic effects in inhibiting angiogenesis, inflammation and tumor growth. Canonical Wnt signaling is the primary pathway for oncogenesis in the mammary gland. In this study, we demonstrate that kallistatin bound to the Wnt coreceptor low-density lipoprotein receptor-related protein 6 (LRP6), thus, blocking Wnt/β-catenin signaling and Wnt-mediated growth and migration in MDA-MB-231 breast cancer cells.

Depletion of endogenous kallistatin exacerbates renal and cardiovascular oxidative stress, inflammation, and organ remodeling.

Kallistatin (KS) levels are reduced in the kidney and blood vessels under oxidative stress conditions. To determine the function of endogenous KS in the renal and cardiovascular systems, KS levels were depleted by daily injection of anti-rat KS antibody into DOCA-salt hypertensive rats for 10 days. Administration of anti-KS antibody resulted in reduced KS levels in the circulation but increased levels of serum thiobarbituric acid reactive substances (an indicator of lipid peroxidation) as well as superoxide formation in the aorta.

Relationship of cortical thickness of the proximal humerus and pullout strength of a locked plate and screw construct.

Background: No study to date has evaluated cortical thickness as it relates to locking plate failure or screw pullout in the proximal humerus. The purpose of this study is to determine the relationship between proximal humerus cortical thickness and locked plate hardware failure in a cadaveric proximal humerus fracture model.

Methods: Twelve humerus specimens were placed into two groups based on the proximal humerus cortical thickness on an anteroposterior radiograph: less than 4 mm and greater than 4 mm.