Corrigendum: Extracorporeal Shock Wave Therapy Enhances the In Vitro Metabolic Activity and Differentiation of Equine Umbilical Cord Blood Mesenchymal Stromal Cells.

[This corrects the article DOI: 10.3389/fvets.2020.554306.].

Terminal Syme Amputation of the Great Toe in the Pediatric Population.

BACKGROUND: In the pediatric population, chronic ingrown toenails (onychocryptosis) can cause infection (paronychia), debilitating pain, and may be unresponsive to conservative treatments. Following multiple failed interventions, a terminal Syme amputation is one option for definitive treatment of chronic onychocryptosis. This procedure involves amputation of the distal aspect of the distal phalanx of the great toe with complete removal of the nail bed and germinal center, preventing further nail growth and recurrence. METHODS: A retrospective review was performed to determine outcomes of a terminal Syme amputation in the pediatric population. Inclusion criteria included treatment of onychocryptosis involving terminal Syme amputation with a minimum follow-up of 1 year. The medical record was reviewed to assess previous failed treatment efforts, perioperative complications, radiographic outcomes, and the need for additional procedures. RESULTS: From 1984 to 2017, 11 patients (13 halluces) with onychocryptosis were treated with a terminal Syme amputation. There were no intraoperative complications. One hallux had a postoperative infection requiring antibiotics as well as partial nail regrowth following the terminal Syme procedure that required subsequent removal of the residual nail. Following partial nail ablation, the patient had no further nail growth. An additional patient also developed a postoperative infection requiring oral antibiotic treatment. All patients returned to full weight-bearing physical activities within 6 weeks of surgery. CONCLUSIONS: Terminal Syme amputation was successful in treating pediatric patients who have recalcitrant onychocryptosis and paronychia. There was little functional consequence following terminal Syme amputation of the great toe in this patient population, making it an effective salvage procedure. LEVEL OF EVIDENCE: Level IV-retrospective comparative study.

Use of a surgical safety checklist after implementation in an academic veterinary hospital.

OBJECTIVE: To determine the use and barriers to uptake of a surgical safety checklist (SSC) after implementation in a veterinary teaching hospital. STUDY DESIGN: Voluntary online survey and retrospective study. SAMPLE POPULATION: All personnel actively involved in the Ontario Veterinary College Health Sciences Centre small animal surgery service between October 2, 2018 and June 28, 2019. METHODS: Surgical case logs and electronically initiated SSC were reviewed to calculate checklist use. The sample population was surveyed to identify factors and barriers associated with use of the SSC. Participants were allowed 1 month to respond, and five reminder emails were sent. RESULTS: Forth-one of 50 (82%) participants completed the survey. The SSC was used in 374 of 784 (47.7%) surgeries. Use rates declined over sequential three-month intervals (P < .0001). Twenty-six of 41 (63%) respondents overestimated checklist use. Staff attitudes were largely supportive of the SSC, with 29 of 41 respondents suggesting mandatory application. Forgetfulness, hierarchal concerns, timing issues, perceived delays in care, lack of clarity regarding roles, and inadequate training were identified as obstacles to use of the SSC. CONCLUSION: The SCC tested in this study was used in approximately half of the surgical procedures performed after its implementation. Hospital personnel were supportive of the SSC; forgetting to use the SSC was the most common barrier identified by respondents (24/41 [59%]). CLINICAL SIGNIFICANCE: The SSC implementation experience and user feedback described here should be taken into consideration to improve design and implementation of future SSC.

Extracorporeal Shock Wave Therapy Enhances the In Vitro Metabolic Activity and Differentiation of Equine Umbilical Cord Blood Mesenchymal Stromal Cells.

Extracorporeal shock wave therapy (ESWT) has been shown to induce different biological effects on a variety of cells, including regulation and stimulation of their function and metabolism. ESWT can promote different biological responses such as proliferation, migration, and regenerations of cells. Recent studies have shown that mesenchymal stromal cells (MSCs) secrete factors that enhance the regeneration of tissues, stimulate proliferation and differentiation of cells, and decrease inflammatory and immune reactions. Clinically, the combination of these two therapies has been used as a treatment for tendon and ligament lesions in horses; however, there is no scientific evidence supporting this combination of therapies in vivo. Therefore, the objectives of the study were to evaluate the effects of ESWT on equine umbilical cord blood mesenchymal stromal cells (CB-MSCs) proliferative, metabolic, migrative, differentiation, and immunomodulatory properties in vitro. Three equine CB-MSC cultures from independent donors were treated using an electrohydraulic shock wave generator attached to a water bath. All experiments were performed as triplicates. Proliferation, viability, migration and immunomodulatory properties of the cells were evaluated. Equine CB-MSCs were induced to evaluate their trilineage differentiation potential. ESWT treated cells had increased metabolic activity, showed positive adipogenic, osteogenic, and chondrogenic differentiation, and showed higher potential for differentiation toward the adipogenic and osteogenic cell fates. ESWT treated cells showed similar immunomodulatory properties to none-ESWT treated cells. Equine CB-MSCs are responsive to ESWT treatment and showed increased metabolic, adipogenic and osteogenic activity, but unaltered immunosuppressive properties. In vivo studies are warranted to determine if synergistic effects occur in the treatment of musculoskeletal injuries if ESWT and equine CB-MSC therapies are combined.

Body composition of medium to giant breed dogs with or without cranial cruciate ligament disease.

OBJECTIVE: To describe the body composition of dogs with or without cranial cruciate ligament (CCL) disease. STUDY DESIGN: Cross-sectional. ANIMALS: Adult dogs in which CCL disease was diagnosed (n = 30) and adult dogs without clinical signs of orthopedic disease (n = 30). METHODS: Body weight, body condition score, and muscle condition score (MCS) were recorded. Body composition of the whole body and pelvic limbs were assessed by dual-energy x-ray absorptiometry. Body condition score, whole body, and pelvic limb body composition measurements were compared by using general linear mixed-model analysis of variance. Muscle condition score between groups was assessed by using a Mann-Whitney U test, while paired data were analyzed by using a Wilcoxon signed-rank test. RESULTS: Body fat percentage (P < .0001) was higher in affected dogs (38.78% ± 1.40) than in control dogs (27.49% ± 1.24). Affected dogs had lower MCS (1.90 ± 0.13, P < .0001) compared with control dogs (2.77 ± 0.08). The affected pelvic limb of affected dogs contained less lean soft tissues (P < .0001) but more fat (P = .0451) compared with the contralateral pelvic limb. CONCLUSION: Dogs with CCL disease were overweight compared with the control group. CLINICAL SIGNIFICANCE: Dogs that are overweight may be predisposed to developing CCL disease. Body composition changes in the pelvic limbs should be considered when managing the care of these dogs.

Contributing factors to surgical site infection after tibial plateau leveling osteotomy: A follow-up retrospective study.

OBJECTIVE: To identify factors associated with surgical site infection (SSI) after tibial plateau leveling osteotomy (TPLO). STUDY DESIGN: Retrospective case series. ANIMALS: Dogs (n = 541) that underwent TPLO (n = 659). METHODS: Medical records of dogs that underwent TPLO from 2011-2018 were reviewed. Data collected included perioperative and postoperative antimicrobial administration, stifle inspection, duration of surgery and anesthesia, comorbidities, and development of SSI including timing, microbiological investigation, and implant removal. Referring veterinarians were contacted for all dogs without a recorded return visit. Risk factors for SSI were assessed by using a multivariable logistic regression model built by using a stepwise approach. RESULTS: Surgical site infection was documented in 71 of 659 (11%) TPLO, with methicillin-resistant Staphylococcus pseudintermedius accounting for 20 of 71 (28%) infections. Protective factors against SSI included administration of postoperative antimicrobials (odds ratio [OR] 0.263; 95% CI = 0.157, 0.442) and timing of preoperative antimicrobial administration. Preoperative antimicrobial timing was protective against SSI when it was administered more than 60 minutes before the first incision compared with administration within 30 minutes (OR 0.275; 95% CI = 0.112, 0.676) or within 60 minutes (OR 0.419; 95% CI = 0.189, 0.929) of the first incision. CONCLUSION: Early administration of perioperative antimicrobials and postoperative antimicrobial administration were protective against SSI after TPLO. CLINICAL SIGNIFICANCE: Antimicrobials can influence the risk of SSI after TPLO. Perioperative and postoperative antimicrobial administration timing should be considered to reduce SSI.

In vitro elution of amikacin and Dispersin B from a polymer hydrogel.

OBJECTIVE: To characterize the in vitro elution of amikacin and Dispersin B (ß-N-acetylglucosaminidase) in a degradable hydrogel. STUDY DESIGN: In vitro, prospective study. METHODS: Amikacin (group A; 40 mg/mL), Dispersin B (group D; 70 µg/mL), or combined amikacin and Dispersin B (group AD; 40 mg/mL and 70 µg/mL, respectively) were added to a hydrogel. Ten aliquots per group were incubated in phosphate-buffered saline that was exchanged at 1, 4, 8, 12, and 24 hours and then once daily for 10 days. Eluted amikacin and Dispersin B were quantitated by using an amikacin reagent kit and a Dispersin B enzyme-linked immunosorbent assay kit, respectively. Time point drug concentrations were compared between groups by using repeated-measures analysis of variance, and total drug elution was compared by using an area under the curve calculation. RESULTS: Amikacin alone, Dispersin B alone, and amikacin and Dispersin B combined together underwent rapid elution in the first 24 hours, followed by a gradual decrease over 10 days. The concentration of Dispersin B eluted in group D was higher at 1 day and lower from day 5 to day 10 compared with that in group AD. The concentration of amikacin eluted in group A was higher at 1, 4, and 8 hours and on day 10 and lower on day 1 compared with that in group AD. The total elution of amikacin was greater from group AD compared with that from group A (P = .02). CONCLUSION: Combining amikacin and Dispersin B had an affect on the total elution of amikacin but not Dispersin B. CLINICAL SIGNIFICANCE: The combination of amikacin and Dispersin B in a degradable hydrogel could allow local treatment of complex infections without the requirement for multiple invasive procedures.

Comparison of methicillin-resistant Staphylococcus pseudintermedius adherence to 2 canine limb salvage endoprosthesis implants.

The objective of our study was to compare adhesion of methicillin-resistant Staphylococcus pseudintermedius (MRSP) to stainless steel (SS) and to tantalum (TA) canine limb salvage endoprosthesis implants in an in vitro experimental study. The median of the mean log10 colony forming units/mL for adherent MRSP was 4.96 (range: 4.63 to 6.33) for the TA endoprosthesis and 4.31 (range: 3.86 to 5.05) for the SS endoprosthesis (P = 0.009). Although the trabecular and porous design of the TA endoprosthesis provides mechanical benefits over the SS endoprosthesis, it may increase the risk of developing infection due to higher levels of bacterial adherence.

Comparaison de l'adhérence deStaphylococcus pseudintermediusrésistant à la méthicilline à deux implants d'endoprothèse pour sauver des membres canins. L'objectif de notre étude consistait à comparer l'adhésion de Staphylococcus pseudintermedius résistant à la méthicilline (MRSP) à des implants d'endoprothèse en acier inoxydable (AI) et en tantale (TA) pour sauver des membres canins lors d'une étude expérimentale in vitro. La médiane des moyennes en log10 des unités formatrices de colonies/mL pour le MRSP adhérent était de 4,96 (écart : de 4,63 à 6,33) pour l'endoprothèse TA et 4,31 (écart : de 3,86 à 5,05) pour l'endoprothèse d'AI (P = 0,009). Même si la conception trabéculaire et poreuse de l'endoprothèse de TA offre des avantages mécaniques par rapport à l'endoprothèse d'AI, elle peut accroître le risque de développer une infection en raison des taux supérieurs d'adhérence bactérienne.(Traduit par Isabelle Vallières).

Characterization and Immunomodulatory Effects of Canine Adipose Tissue- and Bone Marrow-Derived Mesenchymal Stromal Cells.

BACKGROUND: Mesenchymal stromal cells (MSC) hold promise for both cell replacement and immune modulation strategies owing to their progenitor and non-progenitor functions, respectively. Characterization of MSC from different sources is an important and necessary step before clinical use of these cells is widely adopted. Little is known about the biology and function of canine MSC compared to their mouse or human counterparts. This knowledge-gap impedes development of canine evidence-based MSC technologies. HYPOTHESIS AND OBJECTIVES: We hypothesized that canine adipose tissue (AT) and bone marrow (BM) MSC (derived from the same dogs) will have similar differentiation and immune modulatory profiles. Our objectives were to evaluate progenitor and non-progenitor functions as well as other characteristics of AT- and BM-MSC including 1) proliferation rate, 2) cell surface marker expression, 3) DNA methylation levels, 4) potential for trilineage differentiation towards osteogenic, adipogenic, and chondrogenic cell fates, and 5) immunomodulatory potency in vitro. RESULTS: 1) AT-MSC proliferated at more than double the rate of BM-MSC (population doubling times in days) for passage (P) 2, AT: 1.69, BM: 3.81; P3, AT: 1.80, BM: 4.06; P4, AT: 2.37, BM: 5.34; P5, AT: 3.20, BM: 7.21). 2) Canine MSC, regardless of source, strongly expressed cell surface markers MHC I, CD29, CD44, and CD90, and were negative for MHC II and CD45. They also showed moderate expression of CD8 and CD73 and mild expression of CD14. Minor differences were found in expression of CD4 and CD34. 3) Global DNA methylation levels were significantly lower in BM-MSC compared to AT-MSC. 4) Little difference was found between AT- and BM-MSC in their potential for adipogenesis and osteogenesis. Chondrogenesis was poor to absent for both sources in spite of adding varying levels of bone-morphogenic protein to our standard transforming growth factor (TGF-ß3)-based induction medium. 5) Immunomodulatory capacity was equal regardless of cell source when tested in mitogen-stimulated lymphocyte reactions. Priming of MSC with pro-inflammatory factors interferon-gamma and/or tumour necrosis factor did not increase the lymphocyte suppressive properties of the MSC compared to untreated MSC. CONCLUSIONS/SIGNIFICANCE: No significant differences were found between AT- and BM-MSC with regard to their immunophenotype, progenitor, and non-progenitor functions. Both MSC populations showed strong adipogenic and osteogenic potential and poor chondrogenic potential. Both significantly suppressed stimulated peripheral blood mononuclear cells. The most significant differences found were the higher isolation success and proliferation rate of AT-MSC, which could be realized as notable benefits of their use over BM-MSC.

Internal hemipelvectomy for treatment of obstipation secondary to pelvic malunion in 3 cats.

Pelvic fractures are a common injury in cats, and both surgical and conservative management approaches have been described. One of the major complications of pelvic fractures managed conservatively is narrowing of the pelvic canal. Severe pelvic canal narrowing can result in constipation and subsequent megacolon. The purpose of this case series is to describe the long-term outcome for 3 cats with obstipation treated with internal hemipelvectomy because of megacolon secondary to pelvic canal narrowing after conservative management. All cats had a good functional outcome of the affected limb. Two cats required ongoing medical management for recurrent constipation. Overall, internal hemipelvectomy offers good long-term limb function; however, its success in relieving clinical signs of constipation requires additional research.

Hémipelvectomie interne pour le traitement de la constipation opiniâtre secondaire à un cal vicieux pelvien chez 3 chats. Les fractures pelviennes sont une blessure commune chez les chats et les approches chirurgicales et prudentes ont toutes deux été décrites. L'une des complications majeures des fractures pelviennes gérées de manière prudente consiste à raccourcir le canal pelvien. Un rétrécissement sévère du canal pelvien peut se traduire par la constipation et un mégacôlon subséquent. Le but de cette série de cas consiste à décrire le résultat à long terme pour 3 chats souffrant de constipation opiniâtre traitée par une hémipelvectomie interne en raison d'un mégacôlon secondaire au rétrécissement du canal pelvien après une gestion prudente. Tous les chats ont obtenu de bons résultats fonctionnels du membre affecté. Deux chats ont nécessité une gestion médicale permanente pour une constipation opiniâtre. En général, l'hémipelvectomie interne offre une bonne fonction du membre, mais son succès dans le soulagement des signes cliniques de la constipation exige de la recherche additionnelle.(Traduit par Isabelle Vallières).

Evaluation of the Impact of Methicillin-Resistant Staphylococcus pseudintermedius Biofilm Formation on Antimicrobial Susceptibility.

OBJECTIVE: To compare the minimum inhibitory concentration (MIC) of four antimicrobials in planktonic vs. biofilm-associated Staphylococcus pseudintermedius. STUDY DESIGN: In vitro study. SAMPLE POPULATION: 78 isolates from dogs colonized or infected with methicillin-resistant S. pseudintermedius (MRSP, n=39) or methicillin-susceptible S. pseudintermedius (MSSP, n=39). METHODS: Agar dilution was used to determine the MIC of amikacin, cefazolin, enrofloxacin, and gentamicin for planktonic bacteria. A modified broth microdilution assay was used to assess the MIC of biofilm-associated bacteria. RESULTS: MIC were significantly higher in biofilm-associated vs. planktonic bacteria for all antimicrobials; amikacin (median MIC: biofilm >2,000 µg/mL vs. planktonic 3 µg/mL, P<.0001), cefazolin (>1,000 vs. 0.5 µg/mL, P<.0001), enrofloxacin (>1,000 vs. 0.25 µg/mL, P<.0001), and gentamicin (>1,000 vs. 0.3 µg/mL, P<.001). For all antimicrobials, there were significant differences in planktonic MIC for MRSP and MSSP (all P<.0001) but no differences between biofilm MIC for MRSP and MSSP (P=.08-1.0). CONCLUSION: The MIC for biofilm-associated S. pseudintermedius are significantly higher than for planktonic bacteria. Standard methods for determining MIC are not appropriate for biofilm-associated infections. This must be considered when determining treatment regimens for infections that potentially involve biofilms, and further study of methods to control biofilm-associated infections is needed.

An in vitro method to test the safety and efficacy of low-level laser therapy (LLLT) in the healing of a canine skin model.

BACKGROUND: Low-level laser therapy (LLLT) has been used clinically as a treatment modality for a variety of medical conditions including wound-healing processes. It is an attractive and emerging method to enhance wound healing and improve clinical outcomes both in human and veterinary medicine. Despite the fact that the use of LLLT continues to gain in popularity, there is no universally accepted theory that defends all its cellular effects and beneficial biological processes in tissue repair. The present study was designed to evaluate the effect of LLLT on cellular migration and proliferation of cultured canine epidermal keratinocytes (CPEK) in an in vitro wound healing model. RESULTS: Keratinocyte migration and proliferation were assessed using a scratch migration assay and a proliferation assay, respectively. Fifteen independent replicates were performed for each assay. Canine epidermal keratinocyte cells exposed to LLLT with 0.1, 0.2, and 1.2 J/cm(2) migrated significantly more rapidly (p < 0.03) and showed significantly higher rates of proliferation (p < 0.0001) compared to non-irradiated cells cultured in the same medium and cells exposed to the higher energy dose of 10 J/cm(2). Irradiation with 10 J/cm(2) was characterized by decreased cellular migration and proliferation. These results revealed that LLLT has a measurable, dose-dependent effect on two different aspects of keratinocyte biology in vitro. CONCLUSION: In this in vitro wound-healing model, LLLT increased cellular migration and proliferation at doses of 0.1, 0.2, and 1.2 J/cm(2) while exposure to 10 J/cm(2) decreased cellular migration and proliferation. These data suggest that the beneficial effects of LLLT in vivo may be due, in part, to effects on keratinocyte behavior.

Biofilm-Associated Gene Expression in Staphylococcus pseudintermedius on a Variety of Implant Materials.

OBJECTIVE: To evaluate the expression of biofilm-associated genes in Staphylococcus pseudintermedius on multiple clinically relevant surfaces. STUDY DESIGN: In vitro experimental study. SAMPLE POPULATION: Two strains of methicillin-resistant S. pseudintermedius isolated from clinical infections representing the most common international isolates. METHODS: A quantitative polymerase chain reaction (qPCR) assay for expression of genes related to biofilm initial adhesion, formation/maturation, antimicrobial resistance, and intracellular communication was developed and validated. S. pseudintermedius biofilms were grown on 8 clinically relevant surfaces (polymethylmethacrylate, stainless steel, titanium, latex, silicone, polydioxanone, polystyrene, and glass) and samples of logarithmic and stationary growth phases were collected. Gene expression in samples was measured by qPCR. RESULTS: Significant differences in gene expression were identified between surfaces and between bacterial strains for most gene/strain/surface combinations studied. Expression of genes responsible for production of extracellular matrix were increased in biofilms. Expression of genes responsible for initial adhesion and intracellular communication was markedly variable. Antimicrobial resistance gene expression was increased on multiple surfaces, including stainless steel and titanium. CONCLUSION: A method for evaluation of expression of multiple biofilm-associated genes in S. pseudintermedius was successfully developed and applied to the study of biofilms on multiple surfaces. Variations in expression of these genes have a bearing on understanding the development and treatment of implant-associated biofilm infections and will inform future clinical research.

Association between methicillin-resistant Staphylococcus pseudintermedius carriage and the development of surgical site infections following tibial plateau leveling osteotomy in dogs.

OBJECTIVE: To evaluate the association between preoperative carriage of methicillin-resistant Staphylococcus pseudintermedius (MRSP) and the development of surgical site infections (SSIs) following tibial plateau leveling osteotomy (TPLO) in dogs. DESIGN: Prospective multicenter study. ANIMALS: 549 dogs. PROCEDURES: At 7 veterinary hospitals, swab specimens were obtained from the pharynx, nares, rectum, and skin of dogs admitted for TPLO. Specimens were submitted for culture of MRSP. For each dog, information regarding preoperative and postoperative antimicrobial administration, comorbidities, contact with other dogs, and whether the dog developed an SSI was obtained. Univariable and multivariable analyses were performed to identify variables associated with preoperative and postoperative MRSP colonization and the development of an SSI. RESULTS: Of the 549 study dogs, 24 (4.4%) were identified as MRSP carriers before TPLO and 37 (6.7%) developed an SSI after TPLO. Bacteriologic culture was performed on specimens obtained from 32 of the 37 SSIs, and MRSP was isolated from 11 (34%). Carriers of MRSP (OR, 6.72; 95% confidence interval [CI], 2.12 to 21.4) and Bulldogs (OR, 11.1; 95% CI, 2.07 to 59.3) were at risk for development of an SSI after TPLO, whereas postoperative administration of antimicrobials (OR, 0.36; 95% CI, 0.15 to 0.91) appeared to protect against development of an SSI. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that carriage of MRSP were a risk factor for development of an SSI after TPLO and measures to rapidly identify and treat MRSP carriers are warranted. Postoperative administration of antimicrobials protected against development of an SSI after TPLO.

Canine Platelet Lysate Is Inferior to Fetal Bovine Serum for the Isolation and Propagation of Canine Adipose Tissue- and Bone Marrow-Derived Mesenchymal Stromal Cells.

BACKGROUND: Mesenchymal stromal cells (MSC) are increasingly investigated for their clinical utility in dogs. Fetal bovine serum (FBS) is a common culture supplement used for canine MSC expansion. However, FBS content is variable, its clinical use carries risk of an immune response, and its cost is increasing due to global demand. Platelet lysate (PL) has proven to be a suitable alternative to FBS for expansion of human MSC. HYPOTHESIS AND OBJECTIVES: We hypothesized that canine adipose tissue (AT) and bone marrow (BM) MSC could be isolated and expanded equally in PL and FBS at conventionally-used concentrations with differentiation of these MSC unaffected by choice of supplement. Our objectives were to evaluate the use of canine PL in comparison with FBS at four stages: 1) isolation, 2) proliferation, 3) spontaneous differentiation, and 4) directed differentiation. RESULTS: 1) Medium with 10% PL was unable to isolate MSC. 2) MSC, initially isolated in FBS-supplemented media, followed a dose-dependent response with no significant difference between PL and FBS cultures at up to 20% (AT) or 30% (BM) enrichment. Beyond these respective peaks, proliferation fell in PL cultures only, while a continued dose-dependent proliferation response was noted in FBS cultures. 3) Further investigation indicated PL expansion culture was inducing spontaneous adipogenesis in concentrations as low as 10% and as early as 4 days in culture. 4) MSC isolated in FBS, but expanded in either FBS or PL, maintained ability to undergo directed adipogenesis and osteogenesis, but not chondrogenesis. CONCLUSIONS/SIGNIFICANCE: Canine PL did not support establishment of MSC colonies from AT and BM, nor expansion of MSC, which appear to undergo spontaneous adipogenesis in response to PL exposure. In vivo studies are warranted to determine if concurrent use of MSC with any platelet-derived products such as platelet-rich plasma are associated with synergistic, neutral or antagonistic effects.

MRI-based relationships between spine pathology, intervertebral disc degeneration, and muscle fatty infiltration in chondrodystrophic and non-chondrodystrophic dogs.

BACKGROUND CONTEXT: Human studies have revealed a link between muscle degeneration and low back pain, although the cause and effect of this relationship is not clear. Dogs provide a naturally developing model of intervertebral disc (IVD)-related low back pain that may provide insight into relationships between IVD and muscle degeneration. PURPOSE: This study aimed to quantify, via magnetic resonance imaging (MRI), the magnitude and location of fatty infiltration in spine muscles of chondrodystrophic (CD) and non-chondrodystrophic (NCD) dogs suffering from both intervertebral disc herniation (IVDH) and non-disc-related spinal disorders, and relate this to intervertebral disc degeneration (IVDD). STUDY DESIGN: This study used retrospective MRI-based analysis of IVDD and muscle fatty infiltration in CD and NCD dogs. METHODS: A portion of this study was funded ($1,000) by the Pet Trust Fund, Ontario Veterinary College. Magnetic resonance imaging from 180 dogs were separated into four groups: (1) CD with IVDH; (2) CD with non-IVDH spinal pathology; (3) NCD with IVDH; (4) NCD with non-IVDH spinal pathology. For each dog at intervertebral levels T12-T13 to L6-L7, IVDD was subjectively graded and muscle-fat indices (MFIndices) were quantified for multifidus, erector spinae, and psoas muscle groups. RESULTS: Intervertebral disc degeneration grade was higher (p<.0001) for CD compared with NCD dogs, and for dogs diagnosed with IVDH compared with dogs with non-IVDH pathology. Muscle-fat indices of multifidus and psoas were higher (p<.01), indicating greater fatty infiltration, for NCD compared with CD dogs, and for dogs with non-IVDH pathology compared with dogs with IVDH. Erector spinae demonstrated higher (p<.0001) MFIndices compared with multifidus and psoas; however, this level of fatty infiltration was not dependent upon breed or pathology. CONCLUSIONS: Dog groups with higher average IVDD grades demonstrated less fatty infiltration within their multifidus and psoas muscles, compared with groups with lower IVDD grades. This finding was consistent across both CD and NCD breeds as well as across dogs presenting with IVDH and those presenting with a non-IVDH spinal pathology. Thus, the presence or severity of IVDD is not uniquely related to fatty infiltration in these muscles, but rather the presence, or possibly severity or chronicity, of general spine pathology is likely a better predictor of fatty infiltration.

Evaluation of hepatic contrast enhancement with a hepatocyte-specific magnetic resonance imaging contrast agent (gadoxetic acid) in healthy dogs.

OBJECTIVE: To determine, by means of MRI, the time to maximal contrast enhancement in T1-weighted images following IV administration of gadoxetic acid in healthy dogs and assess the impact of gadoxetic acid on the signal intensity of T2-weighted images. ANIMALS: 7 healthy dogs. PROCEDURES: No hepatic abnormalities were detected during ultrasonographic examination. Each dog was anesthetized and positioned in dorsal recumbency for MRI. Transverse T1- and T2-weighted images of the liver were acquired prior to and following (at 5-minute intervals) IV injection of 0.1 mL of gadoxetic acid/kg. Signal intensity of the liver parenchyma was measured in 3 regions of interest in the T1- and T2-weighted images before and at various times point after contrast agent administration. Time versus signal-to-noise ratio curves were plotted to determine time to maximal contrast enhancement and contrast agent-related changes in signal intensity in T2-weighted images. RESULTS: Analysis of T1-weighted images revealed that mean ± SD time to maximal enhancement after gadoxetic acid injection was 10.5 ± 3.99 minutes. Signal intensity of T2-weighted images was not significantly affected by gadoxetic acid administration. No injection-related adverse effects were observed in any dog. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that gadoxetic acid can be used for hepatic MRI in healthy dogs and the resultant hepatic enhancement patterns are similar to those described for humans. Maximal contrast enhancement occurred between 10 and 15 minutes after contrast agent injection; thus, T2-weighted images may be obtained in the interval between injection and maximal enhancement for a more time-efficient clinical protocol.

Identification of appropriate reference genes for qPCR studies in Staphylococcus pseudintermedius and preliminary assessment of icaA gene expression in biofilm-embedded bacteria.

BACKGROUND: Quantitative PCR is rapidly becoming the standard method for analyzing gene expression in a wide variety of biological samples however it can suffer from significant error if stably expressed reference genes are not identified on which to base the analysis. Suitable reference genes for qPCR experiments on Staphylococcus pseudintermedius have yet to be identified. RESULTS: Three reference genes in S. pseudintermedius were identified and validated from a set of eight potential genes (proC, gyrB, rplD, rho, rpoA, ftsZ, recA, sodA). Two strains of S. pseudintermedius were used, and primer specificity and efficiency were confirmed and measured. Ranking of the genes with respect to expression stability revealed gyrB, rho and recA as the best reference genes. This combination was used to quantify expression of a single biofilm associated gene, icaA, in logarithmic, stationary and biofilm growth phases, revealing that expression was significantly upregulated in the biofilm growth phase in both strains. CONCLUSION: Three reference genes, gyrB, rho and recA, were identified and validated for use as reference genes for quantitative PCR experiments in S. pseudintermedius. Also, the biofilm associated gene icaA was shown to be significantly upregulated in biofilm samples, consistent with its role in biofilm production.

Investigation of incidence and risk factors for surgical glove perforation in small animal surgery.

OBJECTIVE: To identify incidence and risk factors for surgical glove perforation in small animal surgery. STUDY DESIGN: Observational cohort study. SAMPLE POPULATION: Surgical gloves (n = 2132) worn in 363 surgical procedures. METHODS: All gloves worn by operative personnel were assessed for perforation at end-procedure using a water leak test. Putative risk factors were recorded by a surgical team member. Associations between risk factors and perforation were assessed using multivariable multi-level random-effects logistic regression models to control for hierarchical data structure. RESULTS: At least 1 glove perforation occurred in 26.2% of procedures. Identified risk factors for glove perforation included increased surgical duration (surgery >1 hour OR = 1.79, 95% CI = 1.12-2.86), performing orthopedic procedures (OR = 1.88; 95% CI = 1.23-2.88), any procedure using powered instruments (OR = 1.93; 95% CI = 1.21-3.09) or surgical wire (OR = 3.02; 95% CI = 1.50-6.05), use of polyisoprene as a glove material (OR = 1.59, 95% CI = 1.05-2.39), and operative role as primary surgeon (OR = 2.01; 95% CI = 1.35-2.98). The ability of the wearer to detect perforations intraoperatively was poor, with a sensitivity of 30.8%. CONCLUSIONS: There is a high incidence of unrecognized glove perforations in small animal surgery.

Intra-articular pharmacokinetics of a gentamicin impregnated collagen sponge in the canine stifle: an experimental study.

OBJECTIVE: To investigate local and systemic pharmacokinetics of gentamicin after intra-articular implantation of a gentamicin impregnated collagen sponge (GICS) in the inflamed canine joint. STUDY DESIGN: Descriptive repeated measures experimental study. ANIMALS: Dogs (n = 9). METHODS: Stifle joint inflammation was caused by urate injection. Twenty-four hours later a GICS (gentamicin dose, 6 mg/kg) was arthroscopically implanted. Synovial fluid and plasma gentamicin concentrations were measured for 14 days after implantation, and pharmacokinetic parameters modeled using statistical moment analyses. RESULTS: Intra-articular gentamicin concentrations fell to sub-MIC for Staphylococcus sp. (4 µg/mL) by 22.4 hours (95% CI: 18.6-26.2) after sponge implantation. Cmax synovial was 2397 µg/mL (95%CI: 1161-3634 µg/mL) at 1.2 hours (95%CI: 0.5-1.8 hours). Plasma gentamicin concentrations achieved levels of Cmax plasma = 8.0 µg/mL (95%CI: 6.1-10.0 µg/mL) at 1.5 hours (95%CI: 0.8-2.1) after GICS placement and fell below target trough of 2.0 µg/mL by 5.6 hours (95%CI: 4.7-6.5 hours) after GICS placement. CONCLUSIONS: Intra-articular gentamicin concentration after GICS placement at an IV-equivalent dose reached high levels and declined rapidly. The maximum plasma levels attained were ∼1/3 of the recommended sub-toxic target for people after parenteral gentamicin administration.