Effects of low-intensity pulsed ultrasound on radiographic healing of tibial plateau leveling osteotomies in dogs: a prospective, randomized, double-blinded study.

OBJECTIVE: To determine the influence of low-intensity pulsed ultrasound (LIPUS) on radiographic healing and limb function after uncomplicated, stable osteotomies in dogs. STUDY DESIGN: In vivo, prospective, randomized, double-blinded, placebo-control study. SAMPLE POPULATION: Fifty client-owned dogs. METHODS: Fifty client-owned dogs with naturally occurring unilateral cranial cruciate ligament rupture were enrolled prior to tibial plateau leveling osteotomy. Dogs were assigned to an active (LIPUS) treatment group or a placebo control (SHAM) treatment group via block randomization on the basis of age, weight, and affected limb. Dogs in the LIPUS treatment group underwent LIPUS treatments for 20 minutes daily: 1.5-MHZ ultrasound wave pulsed at 1 kHZ with a 20% duty cycle at an intensity of 30 mW/cm2 for the duration of the study (12 weeks). Radiographic evaluation was performed at 4, 8, 10, and 12 weeks postoperatively to evaluate bone healing. Limb function was assessed with temporal-spatial gait analysis preoperatively and at 4, 8, and 12 weeks postoperatively by using a pressure-sensitive walkway system. RESULTS: Both groups had significant improvement in radiographic score and limb use over time. However, there was no significant difference in radiographic bone healing, or limb use as measured by objective gait analysis detected between the LIPUS treatment group and SHAM treatment group at any point in the study. CONCLUSION: LIPUS treatment did not improve healing in this stable osteotomy model. CLINICAL SIGNIFICANCE: This study does not provide evidence to support the clinical application of LIPUS to stimulate the healing of stable, uncomplicated osteotomies to accelerate bone healing.

Comparison of long-term outcomes associated with three surgical techniques for treatment of cranial cruciate ligament disease in dogs.

OBJECTIVE: To evaluate long-term (>1 year) outcomes with respect to function and complications in dogs undergoing TightRope (TR), tibial plateau leveling osteotomy (TPLO), or tibial tuberosity advancement (TTA) for treatment of cranial cruciate ligament (CCL) disease. STUDY DESIGN: Retrospective clinical cohort study. METHODS: Medical records from 2006 to 2009 were searched and cases included when all data were available and clients returned a completed questionnaire based on their assessment of their dog at least 1 year after surgery. Outcomes associated with TPLO, TTA, and TR were determined and compared based on medical records and questionnaires data regarding return to function, presence and degree of pain, and complications. RESULTS: Case meeting inclusion criteria were: TPLO (n = 65), TR (n = 79), and TTA (n = 18). TTA was associated with significantly (P < .03) higher rates of major complications and subsequent meniscal tears than TPLO and TR, and TPLO had significantly higher rates of major complications and meniscal tears than TR. Percent of function >1 year after surgery was 93.1% + 10.0% for TPLO, 92.7% + 19.3% for TR, and 89.2% + 11.6% for TTA. Significantly (P = 0.016) more TPLO and TR cases were classified as reaching full function than TTA. The highest levels, frequency, and severity of pain were noted in TTA cases, however, no significant differences were noted among groups. CONCLUSION: Long-term outcomes for TPLO and TR were superior to TTA based on subjective client and DVM assessments. Each technique was associated with a high long-term success rate with TR showing the highest safety-to-efficacy ratio.

Intra-Articular Umbilical Cord Derived Mesenchymal Stem Cell Therapy for Chronic Elbow Osteoarthritis in Dogs: A Double-Blinded, Placebo-Controlled Clinical Trial.

Background: Intra-articular stem cell therapy may help alleviate lameness caused by osteoarthritis in dogs. Umbilical cord-derived stem cell (UMSC) therapy has not yet been investigated in a veterinary clinical study. We hypothesized that dogs treated with intra-articular UMSC will have improved limb function and quality of life when compared to dogs treated with a saline placebo injection. Methods: This was a prospective, double-blinded, placebo-controlled clinical trial in client-owned dogs with chronic elbow osteoarthritis with a follow-up time of 6 months. Dogs were assigned to receive intra-articular UMSC (n = 38) or a saline placebo intra-articular injection (n = 30). Outcome measures included the Canine Brief Pain Inventory score (CBPI) and peak vertical force (PVF) from force-platform gait analysis. Treatment was considered successful when there was a decrease in the Pain Severity Score of at least one and a decrease in the Pain Interference Score of at least one from baseline. Success rates and PVF were compared between groups. Results: No adverse effects associated with UMSC were noted. Of the dogs completing the study, treatment success in the UMSC (n = 28) vs. placebo groups (n = 23) was observed in 54 vs. 28% of dogs at 1 month, 50 vs. 27% at 3 months, and 46 vs. 14% at 6 months, respectively. Success rate in the UMSC group was significantly higher than the placebo group at 1 and 6 months after treatment. However, no differences in PVF of the affected limb over time was observed in either group. Conclusions: Intra-articular UMSC for osteoarthritis may improve clinical signs based on owner observations.

Methylthioadenosine phosphorylase, a gene frequently codeleted with p16(cdkN2a/ARF), acts as a tumor suppressor in a breast cancer cell line.

The human methylthioadenosine phosphorylase (MTAP) gene is located on 9p21 and is frequently homozygously deleted, along with p16(cdkN2a/ARF), in a wide variety of human tumors and human tumor-derived cell lines. The function of MTAP is to salvage methylthioadenosine, which is produced as a byproduct of polyamine metabolism. We have reintroduced MTAP into MCF-7 breast adenocarcinoma cells and have examined its effect on the tumorigenic properties of these cells. MTAP expression does not affect the growth rate of cells in standard tissue culture conditions but severely inhibits their ability to form colonies in soft agar or collagen. In addition, MTAP-expressing cells are suppressed for tumor formation when implanted into SCID mice. This suppression of anchorage-independent growth appears to be because of the enzymatic activity of MTAP, as a protein with a missense mutation in the active site does not exhibit this phenotype. MTAP expression causes a significant decrease in intracellular polyamine levels and alters the ratio of putrescine to total polyamines. Consistent with this observation, the polyamine biosynthesis inhibitor alpha-difluoromethylornithine inhibits the ability of MTAP-deficient cells to form colonies in soft agar, whereas addition of the polyamine putrescine stimulates colony formation in MTAP-expressing cells. These results indicate that MTAP has tumor suppressor activity and suggest that its effects may be mediated by altering intracellular polyamine pools.

Biomechanical evaluation of adjunctive cerclage wire fixation for the prevention of periprosthetic femur fractures using cementless press-fit total hip replacement.

Periprosthetic femoral fractures are a common complication associated with cementless press-fit total hip arthroplasty. The use of prophylactic cerclage wire fixation has been advocated to reduce this complication. The objective of this study was to evaluate whether a double loop cerclage wire, used as adjunctive fixation, increased the peak torsional load to failure in femora implanted with press-fit cementless stems. Peak torsional load to failure was compared between femora without adjunctive fixation and femora receiving a 1 mm double loop cerclage wire placed proximally to the lesser trochanter. Femora treated with adjunctive cerclage wire fixation failed at 20% greater peak torque (P = 0.0001). In conclusion, a double loop cerclage wire may aid in the prevention of periprosthetic fractures associated with press-fit cementless femoral stems.

Outcomes and complications following surgical correction of grade IV medial patellar luxation in dogs: 24 cases (2008-2014).

OBJECTIVE To determine short- and long-term outcomes and complications of dogs undergoing surgical correction of grade IV medial patellar luxation (MPL). DESIGN Retrospective case series. ANIMALS 24 dogs (29 stifle joints) that underwent surgical correction of grade IV MPL between March 2008 and April 2014. PROCEDURES Medical records of all dogs were reviewed. When available, long-term follow-up information was obtained for each dog via the orthopedic surgeon (results of orthopedic examination and radiographic interpretation) and the dog's owner (responses to a questionnaire regarding postsurgical outcomes). Types of postsurgical complications and intervals to follow-up data collection were recorded. Recurrence of MPL was recorded separately. Successful outcome was defined as one without catastrophic complication, with owner-reported full or acceptable return to function and a surgeon- and owner-assigned pain or lameness score < 3. RESULTS 24% (7/29) of stifle joints had major complications, and 21% (6) of joints required surgical revision. Grade II to IV recurrence of MPL was identified in 21% (6) of stifle joints. One dog had a catastrophic complication requiring limb amputation. For all other dogs, owner-reported return to function was full or acceptable. Surgeon-assigned pain and lameness scores for all dogs at the final follow-up evaluation were < 2/5 (0 = pain or lameness free). Surgical correction of grade IV MPL had an overall success rate of 93% (27/29). CONCLUSIONS AND CLINICAL RELEVANCE Surgical correction of grade IV MPL in dogs had a favorable overall success rate; however, owners should be counseled regarding the high rate of complications associated with surgery.

Effects of osteogenic inducers on cultures of canine mesenchymal stem cells.

OBJECTIVE: To examine age-related efficacy of bone morphogenetic protein (BMP)-2, ascorbate, and dexamethasone as osteogenic inducers in canine marrow-derived stromal cells (MSCs). SAMPLE POPULATION: Samples of femoral bone marrow obtained from 15 skeletally immature (< 1 year old) and 4 skeletally mature (> 1.5 years old) dogs. PROCEDURE: First-passage canine MSC cultures were treated with 100 microg of ascorbate phosphate/mL, 10(-7)M dexamethasone, 100 ng of BMP-2/mL, or a combination of these osteoinducers. On day 6, cultures were harvested for quantitation of alkaline phosphatase (ALP) activity and isolation of RNA to prepare cDNA for real-time polymerase chain reaction analyses of osteoblast markers. RESULTS: Early markers of osteogenesis were induced in canine MSCs by BMP-2 but not dexamethasone. In young dogs, the combination of BMP-2 and ascorbate yielded the highest ALP mRNA concentrations and activity. This combination also induced significant increases in mRNA for osteopontin and runt-domain transcription factor 2. In comparison to MSCs from immature dogs, those from mature dogs had diminished ALP activity in response to BMP and ascorbate. Results for cultures treated with 3,4-dehydroproline suggested that ascorbate-induced production of extracellular matrix was important for maximal BMP-2 response in canine MSCs. CONCLUSIONS AND CLINICAL RELEVANCE: BMP-2 was capable of inducing markers of osteogenesis in short-term cultures of canine MSCs. In MSCs obtained from skeletally immature dogs, ascorbate was required for maximal effects of BMP These results define optimal conditions for stem cell osteogenesis in dogs and will facilitate development of stem cell-based treatments for dogs with fractures.

S-adenosylhomocysteine, but not homocysteine, is toxic to yeast lacking cystathionine beta-synthase.

Elevated plasma homocysteine is associated with a variety of diseases in humans including coronary heart disease, stroke, peripheral vascular disease, and birth defects. However, the mechanism by which plasma homocysteine affects cells is unknown. We have examined the growth of isogenic wild-type and cystathionine beta-synthase (CBS) deficient yeast in response to homocysteine and its immediate metabolic precursor, S-adenosylhomocysteine (SAH). CBS deficient yeast export significantly more homocysteine into the media than wild-type yeast and have elevated internal pools of homocysteine and SAH. We found that 5 mM homocysteine added to the media had very little effect on the growth of wild-type or CBS deficient yeast, although intracellular homocysteine concentrations increased five- to tenfold. In contrast, as little as 25 microM S-adenosylhomocysteine inhibited the growth of CBS deficient yeast, but had no effect on wild-type yeast. Measurements of the intracellular S-adenosylmethionine (SAM) and SAH indicate that CBS deficient yeast contain reduced SAM/SAH ratios relative to wild-type, and this ratio is further reduced by adding SAH to the media. Growth inhibition by SAH in CBS deficient yeast can be totally reversed by addition of SAM to the media, indicating that the ratio and not absolute level is critical for cell growth. These results suggest that CBS plays a key role in the regulation of the SAM/SAH ratio inside cells and that excessive perturbations of this ratio can inhibit growth. We hypothesize that elevated extracellular homocysteine present in humans may reflect an altered intracellular SAM/SAH ratio and that this may be related to disease pathogenesis.