While the concept that physical forces such as tension and compression are involved in mature tissue modeling is widely accepted, role of these specific types mechanical loading differentiation maturation uncommitted cell like human mesenchymal stem cells (hMSCs) currently unknown. We observed hMSCs have fundamental ability to distinguish between dynamic tensile compressive by regulating distinct gene expression patterns differences can be related conformational changes shape volume. Dynamic...

In Brief Study Design. vivo experiments to examine physiologic consequences and in vitro tests determine immediate biomechanical effects of anular injury by needle puncture. Objective. To whether a relationship exists between induction degenerative changes anulus fibrosus (AF) compromised disc function according size. Summary Background Data. Various studies intervertebral mechanics, degeneration, regeneration involve the creation defect (AF). However, impact puncture, itself, on health are...

To compare the biomechanical performance of a cephalomedullary nail (CMN), proximal femoral locking plate, and 95° angled blade plate in comminuted subtrochanteric fracture model.A model was created with 2-cm gap below lesser trochanter 15 pairs human cadaveric femora confirmed to be nonosteoporotic. The were randomized treatment one previously mentioned 3 devices. Each tested under incrementally increasing cyclic load up 90,000 cycles from 50% 250% body weight simulate progressive bearing...

Abstract Numerous studies have demonstrated the capacity of mechanical strains to modulate cell behavior through several different signaling pathways. Understanding response ligament fibroblasts mechanically induced may provide useful knowledge for treating injury and improving rehabilitation regimens. Biomechanical that quantify in anterior cruciate medial collateral ligaments shown these are subjected 4–5% during normal activities can be strained 7.7% external application loads knee joint....

Pneumonia is common among patients with artificial airways in place. Most prior studies of such pneumonia involve a heterogeneous group patients, usually major medical or surgical illnesses. We studied the incidence isolated closed head injury (CHI) an effort to determine pattern problem absence other injuries and whether development these was comparable that more groups mechanically ventilated patients. 109 initially comatose CHI who were 24 h more. The mean age 30.3 ± 20.2 yr, 72% male,...

An established in vivo mouse model of compression-induced disc degeneration was used to investigate the effects load on matrix catabolism.To determine whether metalloproteinase-2 expression discs is modulated by mechanical and characterize regulation activity.We have previously shown that static compression elicits changes tissue architecture consistent with those seen degeneration. Evidence literature demonstrates existence metalloproteinases both healthy pathologic suggests may influence...

Abstract Introduction Degeneration of the intervertebral disc (IVD) is characterized by marked degradation and restructuring annulus fibrosus (AF). Although several matrix metalloproteinases (MMPs) have been found to be more prevalent in degenerate discs, their coordination function within context disease process are still not well understood. In this study, we sought determine whether MMP-2 associated with degenerative changes AF identify manner which cells use MMP-2. Methods Two...

The defining characteristic of the annulus fibrosus (AF) intervertebral disc (IVD) has long been lamellar structures that consist highly ordered collagen fibers arranged in alternating oblique angles from one layer to next. However, a series recent histologic studies have demonstrated AF lamellae contain elastin- and type VI collagen-rich secondary "cross-bridge" across lamellae. In this study, we use optical coherence tomography (OCT) elucidate three-dimensional (3-D) morphologies these...

Abstract Cells of the nucleus pulposus (NP) in intervertebral disc are derived directly from embryonic notochord. In humans, a shift NP cell population coincides with beginning age‐related changes extracellular matrix that can lead to spinal disorders. To begin identifying bases these changes, manner by which relevant environmental factors impact function must be understood. This study investigated roles biochemical, nutritional, and physical regulating immature cells. Specifically, we...

Allograft tendons are frequently used for ligament reconstruction about the knee, but they entail availability and cost challenges. The identification of other tissues that demonstrate equivalent performance to preferred would improve limitations. Hypothesis/Purpose: We compared biomechanical properties 4 soft tissue allograft tendons: tibialis anterior (TA), posterior (TP), peroneus longus (PL), semitendinosus (ST). hypothesized be similar when standardized by looped diameter.Controlled...

We developed a miniature fiber optic pressure sensor system and utilized it for in vitro intradiscal measurements rodents. One of the unique features this work is design fabrication element with multilayer polymer-metal diaphragm. This diaphragm consists base polyimide layer (150 nm thick), metal reflective (1 µm another protection isolation thick). The biocompatible can be fabricated by simple, batch-fabrication methods non-cleanroom environment good device-to-device uniformity. has an...

Objective: It has been proposed that 2.5 cm of diastasis the symphysis pubis corresponds with injury to anterior sacroiliac ligament and differentiates Young-Burgess anteroposterior compression Type I II pelvic ring injuries. We hypothesized if a pelvis greater than diastasis, ligaments are disrupted floor failed. Methods: Pure torsional moment was applied cadaveric human pelves hemipelvis either unconstrained (n = 10) or constrained move only in plane rotation 10). recorded displacement...

Objectives: The 95° angled blade plate is an accepted standard for plating subtrochanteric femoral fractures but can be technically demanding and often requires extensive soft tissue exposure. Proximal locking plates (PFLPs) have been developed pertrochanteric are potentially easier to apply with less dissection. Clinical experience has raised concerns regarding the strength of PFLP. purpose our study was compare relative stability two designs PFLP under loads simulating first 3 months...

Objectives: The purpose of this study is to determine if recent innovations in olecranon plates have any advantages stabilizing osteoporotic fractures. Methods: Five (Acumed, Synthes-SS, Synthes-Ti, US Implants/ITS, and Zimmer) were implanted stabilize a simulated comminuted fracture pattern 30 cadaveric elbows. Specimens randomized by bone mineral density per dual-energy x-ray absorptiometry scan. Three-dimensional displacement analysis was conducted assess fragment motion through...