Co-deleting Pten with Rb in retinal progenitor cells in mice results in fully penetrant bilateral retinoblastomas.

Background: Rb1 is the most frequently mutated gene in the pediatric cancer retinoblastoma, and its loss causes E2F transcription factors to induce proliferation related genes. However, high E2F levels following pRB loss also induce apoptosis-promoting genes as a safeguard mechanism to suppress emergent tumors. Although p53 accumulation and apoptosis induction is believed to be a primary mechanism to eliminate cells with excess E2F activity, p53 deletion doesn't suppress RB/E2F induced apoptosis in vivo in the retina.

Inhibition of angiogenesis and suppression of colorectal cancer metastatic to the liver using the Sleeping Beauty Transposon System.

Background: Metastatic colon cancer is one of the leading causes of cancer-related death worldwide, with disease progression and metastatic spread being closely associated with angiogenesis. We investigated whether an antiangiogenic gene transfer approach using the Sleeping Beauty (SB) transposon system could be used to inhibit growth of colorectal tumors metastatic to the liver.

Results: Liver CT26 tumor-bearing mice were hydrodynamically injected with different doses of a plasmid containing a transposon encoding an angiostatin-endostatin fusion gene (Statin AE) along with varying amounts of SB transposase-encoding plasmid.

Effect of intra-articular pressurization associated with arthroscopy on the immature physis: investigation in an animal model.

Background: Despite the increased use of arthroscopy in pediatric orthopaedics, there is a paucity of data regarding the potential long-term effects of this procedure on the immature physis. The purpose of this study was to test the hypothesis that elevated intra-articular pressures used during arthroscopic surgery do not result in growth disturbances or morphologic alterations in the epiphyseal plate.

Methods: Twenty-seven 6-week-old skeletally immature New Zealand white rabbits were divided into experimental (n=21) and control groups (n=6).

A comparative analysis of 7.0-Tesla magnetic resonance imaging and histology measurements of knee articular cartilage in a canine posterolateral knee injury model: a preliminary analysis.

Background: There has recently been increased interest in the use of 7.0-T magnetic resonance imaging for evaluating articular cartilage degeneration and quantifying the progression of osteoarthritis.

Purpose: The purpose of this study was to evaluate articular cartilage cross-sectional area and maximum thickness in the medial compartment of intact and destabilized canine knees using 7.

The 1:1 versus the 2:2 tunnel-drilling technique: optimization of fixation strength and stiffness in an all-inside double-bundle anterior cruciate ligament reconstruction--a biomechanical study.

Background: Double-bundle anterior cruciate ligament (ACL) reconstructions involve drilling 2 tibial tunnels separated by a narrow 2-mm bone bridge. The sequence of reaming and drilling the tibial tunnels for double-bundle ACL reconstructions has not been defined.

Hypothesis: Fixing a graft in the posterolateral ACL tibial tunnel before reaming the anteromedial tibial tunnel will reduce the number of complications, as compared with drilling both the anteromedial and posterolateral tunnels before graft fixation, when performing double-bundle ACL reconstructions.

Systemic correction of storage disease in MPS I NOD/SCID mice using the sleeping beauty transposon system.

The Sleeping Beauty (SB) transposon system is a nonviral vector that directs transgene integration into vertebrate genomes. We hydrodynamically delivered SB transposon plasmids encoding human alpha-L-iduronidase (hIDUA) at two DNA doses, with and without an SB transposase gene, to NOD.129(B6)-Prkdc(scid) IDUA(tm1Clk)/J mice.

A comparison between a retrograde interference screw, suture button, and combined fixation on the tibial side in an all-inside anterior cruciate ligament reconstruction: a biomechanical study in a porcine model.

Background: Effective soft tissue graft fixation to the tibial tunnel in all-inside anterior cruciate ligament reconstructions has been reported to be a problem and may lead to retrograde pullout at ultimate load testing.

Hypothesis: A combined retrograde bioabsorbable screw and cortical-cancellous suture button suspension apparatus would gain stiffness from the button and strength from the screw, thus providing for a larger pullout ultimate load, yield load, and stiffness when compared with either fixation alone in an all-inside anterior cruciate ligament reconstruction.

Study Design: Controlled laboratory study.

Assessment of a goat model of posterolateral knee instability.

The development of an in vivo animal model of posterolateral knee instability is desired for devising effective interventions for this injury. Sequential sectioning of the popliteus tendon, lateral collateral ligament, and lateral capsule was done in cadaveric goat knees to create knee joint instability, followed by in vivo studies (Studies 1 and 2) of 7 and 3 months duration, respectively. In Study 1, the popliteus tendon and lateral collateral ligament were sectioned; in Study 2, these structures as well as the lateral joint capsule were sectioned.