Stabilization of the CORA based leveling osteotomy for treatment of cranial cruciate ligament injury using a bone plate augmented with a headless compression screw.

OBJECTIVE: To report the effectiveness of a bone plate/headless compression screw (HCS) construct in preventing tibial plateau angle (TPA) shift postoperatively and to describe radiographic healing of the osteotomy. STUDY DESIGN: Case series. ANIMALS: Dogs (n = 31). METHODS: Records of dogs diagnosed with cranial cruciate ligament (CCL) injury treated with the center of rotation of angulation (CORA) based leveling osteotomy (CBLO) stabilized with a bone plate augmented with a HCS were reviewed. Breed, age, weight, and gender were recorded. Radiographs were reviewed for determination of preoperative tibial plateau angle (PreTPA), postoperative TPA (PostTPA), patellar tendon angle (PTA) postoperatively, and TPA at final evaluation (FinalTPA). Difference between PostTPA and FinalTPA was used to define any TPA shift. Radiographic healing at final evaluation was graded based on a 5-point scale. RESULTS: Mean time to final recheck was 88 days (range 49-237 days) with mean ± SD PreTPA = 28.6 ± 4.8°; PostTPA = 9.2 ± 2.2°; FinalTPA = 9.7 ± 2.6°; and TPA Shift = 0.52 ± 1.61°. There was no significant difference between PostTPA and FinalTPA (P = .084, power > 0.80). Mean postoperative PTA was 89.9 ± 1.7°. There were 2 implant related complications; 1 HCS migration and 1 HCS failure. CONCLUSION: Stabilization of the CBLO using a bone plate augmented with a HCS was effective in maintaining PostTPA and achieving satisfactory radiographic healing.

Transfection of the DNA for the receptor KDR/flk-1 attenuates neointimal proliferation and luminal narrowing in a coronary stent angioplasty model.

BACKGROUND: Neointimal proliferation resulting in luminal renarrowing is the major cause of restenosis limiting the long-term success of coronary angioplasty in 20 to 30% of patients. Local transfection of the DNA encoding for VEGF has been shown to enhance re-endothelialization and reduce neointimal proliferation in an experimental model. We tested the hypothesis that transfection of the DNA for the receptor of vascular endothelial growth factor VEGF, KDR-flk-1, reduces neointimal proliferation after angioplasty. METHODS: In a minipig model, we performed coronary stent implantation, followed by injection of either KDR/flk-1 DNA (200 microg of linearized DNA in a CMV-promotor) or LacZ control in two coronary artery segments per animal in a randomized, blinded protocol (n = 22 animals). Expression of KDR/flk-1 was analyzed using in situ hybridization after 4, 7, and 14 days. RESULTS: In KDR-transfected coronary segments, expression of KDR/flk-1 occurred earlier and to much stronger extent compared to LacZ-transfected segments. After 4 weeks (n = 10) neointimal proliferation and luminal narrowing was significantly reduced in KDR/flk-1 transfected animals. No expression of locally transfected DNA was detected in other organs. CONCLUSION: The hypothesis is supported, that expression of the VEGF-receptor KDR/flk-1 can be rate-limiting for endothelial regeneration and that its transient overexpression at the time angioplasty can prevent excessive neointimal proliferation resulting in restenosis.

Evaluation of 99MTC-diethylenetriaminepentaacetic acid renal scintigram curves in normal dogs after induction of diuresis.

The normal 99mTc-diethylenetriaminepentaacetic acid (DTPA) renal scintigram curve has 3 distinct phases; an arterial phase followed by progressive uptake and subsequent excretion from the kidney. In dogs with X-linked hereditary nephritis, a distinct flattening of the renal scintigram curve has been observed prior to any decline in glomerular filtration rate (GFR). The cause of this shape change is not known, however, it coincided with decreased urine-specific gravity and thus might be related to polyuria. To further evaluate this possibility, we assessed whether diuresis without concurrent renal disease could flatten the 99mTc-DTPA renal scintigram curve. GFR scintigraphy was performed in six healthy dogs once as a baseline, and again after induction of diuresis by each of four different methods. Scintigram curves were evaluated subjectively as well as quantitatively by calculation of GFR estimates, mean renal transit times, time to peak activity and half-time clearance. Complete flattening of the renal scintigram curve did not occur with diuresis alone, and therefore, flattening of the scintigram curve may serve as an early indicator of renal dysfunction. However, during diuresis after intravenous saline administration, alterations in time to peak activity and mean renal transit time may create inaccuracies in GFR estimates based on the conventional regression formula that cause a false lowering of the resultant global GFR value.