Temporal memory for threatening events encoded in a haunted house.

Despite the salient experience of encoding threatening events, these memories are prone to distortions and often non-veridical from encoding to recall. Further, threat has been shown to preferentially disrupt the binding of event details and enhance goal-relevant information. While extensive work has characterised distinctive features of emotional memory, research has not fully explored the influence threat has on temporal memory, a process putatively supported by the binding of event details into a temporal context. Two primary competing hypotheses have been proposed; that threat can impair or enhance temporal memory. We analysed two datasets to assess temporal memory for an in-person haunted house experience. In study 1, we examined the temporal structure of memory by characterising memory contiguity in free recall as a function of individual levels of heart rate as a proxy of threat. In study 2, we replicated marginal findings of threat-related increases in memory contiguity found in study 1. We extended these findings by showing threat-related increases in recency discriminations, an explicit test of temporal memory. Together, these findings demonstrate that threat enhances temporal memory regarding free recall structure and during explicit memory judgments.

Comparison of Trauma in Dogs due to Direct Motor Vehicle Collision or Fall from Open Pick-up Truck Bed during Transportation (2002-2020).

OBJECTIVE: The aim of this study was to report injuries sustained by dogs following motor vehicle trauma: direct motor vehicle collision (MVC), and fall from an open pickup truck bed during transportation (PTB). STUDY DESIGN: Medical records of dogs involved in motor vehicle trauma between 2002 and 2020 were reviewed. Signalment, mode of injury, injuries sustained, and treatments performed were recorded. An owner questionnaire investigated effects of the trauma on the dog and owner. RESULTS: Six hundred and ninety-eight dogs met the inclusion criteria (569 MVC, 102 PTB). Orthopaedic trauma was significantly more common after PTB (90.2%) (MVC, 75.6%; p = 0.011). There were not any differences in the prevalence of soft tissue injuries between groups (76.4% MVC, 67.6% PTB; p = 0.058), however, MVC dogs had significantly more thoracic (26.9% MVC, 4.4% PTB) and abdominal (12.9% MVC, 0% PTB) trauma (p <0.001). Surgical treatments were performed significantly more often after PTB (71.6%) (MVC, 47.6%) (p <0.001). Discharge rate after PTB (95.0%) was significantly higher (MVC, 84.0%) (p <0.001). Aftercare was reported to be significantly more difficult after PTB (76.2%) (MVC, 34.0%; p = 0.002). CONCLUSION: MVC and PTB result in significantly different trauma. PTB causes predominantly orthopaedic and integument injuries, whereas MVC results in thoracic and abdominal trauma. Survival to discharge is greater following PTB than MVC.

Adolescent-specific memory effects: evidence from working memory, immediate and long-term recognition memory performance in 8-30 yr olds.

Working memory and recognition memory develop across adolescence, but the relationship between them is not fully understood. We investigated associations between n-back task performance and subsequent recognition memory in a community sample (8-30 yr, n = 150) using tasks from the Adolescent Brain Cognitive Development Study (ABCD Study) to cross-sectionally assess memory in an age range that will be sampled longitudinally. We added a 24-h delay condition to assess long-term recognition. Overall working memory, immediate and long-term recognition performance peaked in adolescence. Age effects in recognition memory varied by items (old targets, old distractors, and new items) and delay (0 and 24 h). For immediate recognition, accuracy was higher for targets and new items than for distractors, with accuracy for targets peaking in adulthood and accuracy for new items peaking during adolescence. For long-term recognition, adolescents' accuracy was higher for targets than distractors, while adults showed similarly high accuracy for targets and distractors and children showed low accuracy for both. This pattern appeared to be specific to recognition of items from the high working memory load condition. The results suggest that working memory may facilitate long-term recognition of task-relevant over irrelevant items and may benefit the detection of new information during adolescence.

An open-access accelerated adult equivalent of the ABCD Study neuroimaging dataset (a-ABCD).

As public access to longitudinal developmental datasets like the Adolescent Brain Cognitive Development StudySM (ABCD Study®) increases, so too does the need for resources to benchmark time-dependent effects. Scan-to-scan changes observed with repeated imaging may reflect development but may also reflect practice effects, day-to-day variability in psychological states, and/or measurement noise. Resources that allow disentangling these time-dependent effects will be useful in quantifying actual developmental change. We present an accelerated adult equivalent of the ABCD Study dataset (a-ABCD) using an identical imaging protocol to acquire magnetic resonance imaging (MRI) structural, diffusion-weighted, resting-state and task-based data from eight adults scanned five times over five weeks. We report on the task-based imaging data (n = 7). In-scanner stop-signal (SST), monetary incentive delay (MID), and emotional n-back (EN-back) task behavioral performance did not change across sessions. Post-scan recognition memory for emotional n-back stimuli, however, did improve as participants became more familiar with the stimuli. Functional MRI analyses revealed that patterns of task-based activation reflecting inhibitory control in the SST, reward success in the MID task, and working memory in the EN-back task were more similar within individuals across repeated scan sessions than between individuals. Within-subject, activity was more consistent across sessions during the EN-back task than in the SST and MID task, demonstrating differences in fMRI data reliability as a function of task. The a-ABCD dataset provides a unique testbed for characterizing the reliability of brain function, structure, and behavior across imaging modalities in adulthood and benchmarking neurodevelopmental change observed in the open-access ABCD Study.

Behavioral and Neural Signatures of Working Memory in Childhood.

Working memory function changes across development and varies across individuals. The patterns of behavior and brain function that track individual differences in working memory during human development, however, are not well understood. Here, we establish associations between working memory, other cognitive abilities, and functional MRI (fMRI) activation in data from over 11,500 9- to 10-year-old children (both sexes) enrolled in the Adolescent Brain Cognitive Development (ABCD) Study, an ongoing longitudinal study in the United States. Behavioral analyses reveal robust relationships between working memory, short-term memory, language skills, and fluid intelligence. Analyses relating out-of-scanner working memory performance to memory-related fMRI activation in an emotional n-back task demonstrate that frontoparietal activity during a working memory challenge indexes working memory performance. This relationship is domain specific, such that fMRI activation related to emotion processing during the emotional n-back task, inhibitory control during a stop-signal task (SST), and reward processing during a monetary incentive delay (MID) task does not track memory abilities. Together, these results inform our understanding of individual differences in working memory in childhood and lay the groundwork for characterizing the ways in which they change across adolescence.SIGNIFICANCE STATEMENT Working memory is a foundational cognitive ability that changes over time and varies across individuals. Here, we analyze data from over 11,500 9- to 10-year-olds to establish relationships between working memory, other cognitive abilities, and frontoparietal brain activity during a working memory challenge, but not during other cognitive challenges. Our results lay the groundwork for assessing longitudinal changes in working memory and predicting later academic and other real-world outcomes.

Feel the bass: Music presented to tactile and auditory modalities increases aesthetic appreciation and body movement.

Music is both heard and felt-tactile sensation is especially pronounced for bass frequencies. Although bass frequencies have been associated with enhanced bodily movement, time perception, and groove (the musical quality that compels movement), the underlying mechanism remains unclear. In 2 experiments, we presented high-groove music to auditory and tactile senses and examined whether tactile sensation affected body movement and ratings of enjoyment and groove. In Experiment 1, participants (N = 22) sat in a parked car and listened to music clips over sound-isolating earphones (auditory-only condition), and over earphones plus a subwoofer that stimulated the body (auditory-tactile condition). Experiment 2 (N = 18) also presented music in auditory-only and auditory-tactile conditions, but used a vibrotactile backpack to stimulate the body and included 2 loudness levels. Participants tapped their finger with each clip, rated each clip, and, in Experiment 1, we additionally video recorded spontaneous body movement. Results showed that the auditory-tactile condition yielded more forceful tapping, more spontaneous body movement, and higher ratings of groove and enjoyment. Loudness had a small, but significant, effect on ratings. In sum, findings suggest that bass felt in the body produces a multimodal auditory-tactile percept that promotes movement through the close connection between tactile and motor systems. We discuss links to embodied aesthetics and applications of tactile stimulation to boost rhythmic movement and reduce hearing damage. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Effects of low-level laser therapy on bone healing and signs of pain in dogs following tibial plateau leveling osteotomy.

OBJECTIVE To assess the effect of low-level laser therapy (LLLT) on markers of synovial inflammation and signs of pain, function, bone healing, and osteoarthritis following tibial plateau leveling osteotomy (TPLO) in dogs with spontaneous cranial cruciate ligament rupture (CCLR). ANIMALS 12 client-owned dogs with unilateral CCLR. PROCEDURES All dogs were instrumented with an accelerometer for 2 weeks before and 8 weeks after TPLO. Dogs were randomly assigned to receive LLLT (radiant exposure, 1.5 to 2.25 J/cm2; n = 6) or a control (red light; 6) treatment immediately before and at predetermined times for 8 weeks after TPLO. Owners completed a Canine Brief Pain Inventory weekly for 8 weeks after surgery. Each dog underwent a recheck appointment, which included physical and orthopedic examinations, force plate analysis, radiography and synoviocentesis of the affected joint, and evaluation of lameness and signs of pain, at 2, 4, and 8 weeks after surgery. Select markers of inflammation were quantified in synovial fluid samples. Variables were compared between the 2 groups. RESULTS For the control group, mean ground reaction forces were greater at 2 and 4 weeks after TPLO and owner-assigned pain scores were lower during weeks 1 through 5 after TPLO, compared with corresponding values for the LLLT group. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the LLLT protocol used had no beneficial effects on signs of pain or pelvic limb function following TPLO. Further research is necessary to evaluate the effects of LLLT and to determine the optimum LLLT protocol for dogs with CCLR.

Pharmacokinetic Analysis of an Oral Multicomponent Joint Dietary Supplement (Phycox®) in Dogs.

Despite the lack of safety, efficacy and pharmacokinetic (PK) studies, multicomponent dietary supplements (nutraceuticals) have become increasingly popular as primary or adjunct therapies for clinical osteoarthritis in veterinary medicine. Phycox® is a line of multicomponent joint support supplements marketed for joint health in dogs and horses. Many of the active constituents are recognized anti-inflammatory and antioxidant agents. Due to a lack of PK studies in the literature for the product, a pilot PK study of select constituents in Phycox® was performed in healthy dogs. Two novel methods of analysis were developed and validated for quantification of glucosamine and select polyphenols using liquid chromatography-tandem mass spectrometry. After a single oral (PO) administrated dose of Phycox®, a series of blood samples from dogs were collected for 24 h post-dose and analyzed for concentrations of glucosamine HCl, hesperetin, resveratrol and naringenin. Non-compartmental PK analyses were carried out. Glucosamine was detected up to 8 h post-dose with a Tmax of 2 h and Cmax of 9.69 µg/mL. The polyphenols were not found at detectable concentrations in serum samples. Co-administration of glucosamine in the Phycox® formulation may enhance the absorption of glucosamine as determined by comparison of glucosamine PK data in the literature.

The effect of nail characteristics on surface bacterial counts of surgical personnel before and after scrubbing.

OBJECTIVE: To determine the influence of nail characteristics on bacterial counts on the fingers of surgery personnel. STUDY DESIGN: Randomized nonblinded controlled crossover study design. SAMPLE POPULATION: Veterinary students, small animal surgery technicians, small animal surgery interns/residents, and small animal surgery faculty in a veterinary teaching hospital (n = 21). METHODS: Subjects were randomized into one of 2 groups; group 1 wore nail polish (P) for 1 week and group 2 (control) had nonpolished (NP) fingernails. Each subject changed groups the following week. Fingernail lengths were measured each day and fingernail samples were collected before and after presurgical scrub and after surgery. Total bacterial counts (TBC) and suspected staphylococci were counted on blood agar media and mannitol salt agar. The association between bacterial counts and nail biting, position of the volunteer, duration of the surgery, whether the nail polish was chipped, duration of nail polish application, type of surgery, and handedness was tested. Log-transformed CFU counts were compared with a Student's t test and presence or absence of bacteria were compared using Fisher's exact test. RESULTS: TBC, quantities of staphylococci, other gram-positive organisms, and gram-negative bacilli did not differ between P and NP personnel. The only variable associated with higher bacterial counts consisted of nail lengths greater than 2 mm. CONCLUSION: Nail polish did not influence bacterial counts and types of isolates, but nail length is a risk factor for increased bacterial counts. Based on our results, we recommend that nail length be kept under 2 mm.

The effect of lysophosphatidic acid using a hydrogel or collagen sponge carrier on bone healing in dogs.

OBJECTIVES: The purposes of this study were to determine: 1) the efficacy of polycaprolactone-g-polyethylene glycol (PCL-g-PEG) and polylactic-co-glycolic acid (PLGA-g-PEG) hydrogels and an absorbable collagen sponge (ACS) as carriers for lysophosphatidic acid (LPA), 2) the effect of LPA on bone healing in dogs, and 3) the ideal dose of LPA to maximally stimulate bone healing. METHODS: Bilateral ulnar ostectomies were performed on purpose bred dogs. Control defects were filled with a PCL-g-PEG or PLGA-g-PEG hydrogel, or a saline soaked ACS. Contralateral defects were filled with a PCL-g-PEG or PLGA-g-PEG hydrogel, or an ACS with each carrying differing concentrations of an LPA solution. Dual-energy X-ray absorptiometry (DXA) was performed. Total bone area (TBA), mineral density (BMD), and mineral content (BMC) were determined at each time point. Relationships between the effect of treatment over time on TBA, BMC and BMD were determined. RESULTS: Phase 1 - There was no significant difference in DXA-based TBA (p = 0.09), BMC (p = 0.33), or BMD (p = 0.74) over time between LPA treatments, or between the LPA treated and control groups TBA (p = 0.95), BMC (p = 0.99), or BMD (p = 0.46). Phase 2 - There was no significant difference over time between LPA treatments in DXA-based TBA (p = 0.33), BMC (p = 0.45), or BMD (p = 0.43), or between the LPA treated and control groups TBA (p = 0.94), BMC (p = 0.38), or BMD (p = 0.17). Phase 3 - There was no significant difference over time between LPA treatments in DXA-based TBA (p = 0.78), BMC (p = 0.88), or BMD (p = 0.35), or between the LPA treated and control groups TBA (p = 0.07), BMC (p = 0.85), or BMD (p = 0.06). There was a significant increase in TBA (p <0.0001) and BMC (p = 0.0014), but a significant decrease in BMD (p <0.0001) was noted over time when all groups were combined. CLINICAL SIGNIFICANCE: Although LPA has shown promise as an osteoinductive agent in research, its performance as a bone graft substitute, as utilized in this study, is unsupported. Further studies are necessary to determine the incorporation and elution kinetics of LPA from the PLGA-g-PEG hydrogel and from an ACS. Hydrogels may have clinical applications for delaying or preventing bone formation.

Pharmacological effects of a C-phycocyanin-based multicomponent nutraceutical in an in-vitro canine chondrocyte model of osteoarthritis.

Multicomponent nutraceuticals are becoming increasingly popular treatments or adjunctive therapies for osteoarthritis in veterinary medicine despite lack of evidence of efficacy for many products. The objective of this study was to evaluate the anti-inflammatory and antioxidant activities of a commercially available C-phycocyanin-based nutraceutical and select constituent ingredients in an in-vitro model of canine osteoarthritis. Normal canine articular chondrocytes were used in an in-vitro model of osteoarthritis. Inflammatory conditions were induced using interleukin-1ß. The nutraceutical preparation as a whole, its individual constituents, as well as carprofen were evaluated at concentrations of 0 to 250 µg/mL for reduction of the following inflammatory mediators and indicators of catabolism of the extracellular matrix: prostaglandin E2 (PGE2), tumor necrosis factor-α (TFN-α), interleukin-6 (IL-6), metalloproteinase-3 (MMP-3), nitric oxide, and sulfated glycosaminoglycans (sGAGs). Validated, commercially available assay kits were used for quantitation of inflammatory mediators. The antioxidant capacities, as well as cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and lipoxygenase (LOX) inhibitory activities of the whole nutraceutical preparation and select constituents, were also assessed using validated commercially available assay kits. The antioxidant capacity of the nutraceutical and constituents was concentration-dependent. The nutraceutical and constituents appear to display anti-inflammatory activity primarily through the inhibition of COX-2. The nutraceutical displayed similar strength to carprofen in reducing TNF-α, IL-6, MMP-3, nitric oxide, and sGAGs at select concentration ranges. The C-phycocyanin (CPC)-based nutraceutical and constituents may be able to mediate 3 primary pathogenic mechanisms of osteoarthritis: inflammation, chondral degeneration, and oxidative stress in vitro. The nutraceutical may be clinically useful in veterinary medicine and its efficacy should be further investigated in vivo.

Les neutraceutiques à composés multiples deviennent de plus en plus populaires en médecine vétérinaire comme traitement ou thérapie alternative pour soigner l'ostéoarthrite, et ce malgré le manque d'évidence de l'efficacité de plusieurs produits. L'objectif de la présente étude était d'évaluer l'activité anti-inflammatoire et anti-oxydante d'un neutraceutique à base de C-phycocyanine disponible commercialement, et d'ingrédients constitutifs sélectionnés dans un modèle in vitro d'ostéoarthrite canine. Des chondrocytes articulaires canins normaux furent utilisés dans un modèle in vitro d'ostéoarthrite. Des conditions inflammatoires ont été induites en utilisant de l'interleukine-1ß. La préparation neutraceutique complète, ses constituants individuels, de même que du caprofène furent évalués à des concentrations de 0 à 250 µg/mL pour la réduction des médiateurs de l'inflammation suivants et des indicateurs du catabolisme de la matrice extracellulaire: prostaglandine E2 (PGE2), facteur-α nécrosant des tumeurs (TNF-α), interleukine-6 (IL-6), métalloprotéinase-3 (MMP-3), oxyde nitreux, et les glycosaminoglycans sulfatés (sGAGs). Des trousses commerciales validées furent utilisées pour la quantification des médiateurs de l'inflammation. Les capacités anti-oxydantes, de même que l'activité inhibitrice envers la cyclo-oxygénase 1 (COX-1), la cyclo-oxygénase-2 (COX-2), et la lipoxygénase (LOX) de la préparation neutraceutique complète et de constituants sélectionnés furent également évaluées au moyen de de trousses commerciales disponibles commercialement. La capacité anti-oxydante du neutraceutique et des constituants était dépendante de la concentration. Le neutraceutique et les constituants semblent manifester leur activité anti-inflammatoire principalement via l'inhibition de COX-2. Dans des écarts de concentrations sélectionnés, le neutraceutique a démontré une capacité similaire au carprofène en réduisant TNF-α, IL-6, MMP-3, oxyde nitreux, et sGAGs. Le neutraceutique à base de C-phycocyanine (CPC) et ses constituants peuvent être en mesure de médier trois mécanismes pathogéniques primaires de l'ostéo-arthrite: l'inflammation, la dégénération chondrale, et le stress oxydatif in vitro. Le neutraceutique pourrait être cliniquement utile en médecine vétérinaire et son efficacité devrait être investigué plus à fond in vivo.(Traduit par Docteur Serge Messier).

Evaluation of the drawer test and the tibial compression test for differentiating between cranial and caudal stifle subluxation associated with cruciate ligament instability.

OBJECTIVE: To determine the sensitivity and specificity of the drawer test (DT) alone and in combination with the tibial compression test (TCT) to detect stifle subluxation after transection of the cranial cruciate (CrCL), caudal cruciate (CdCL) or both cruciate ligaments (total cruciate ligament or TCL). STUDY DESIGN: Experimental study. SAMPLE POPULATION: Cadaveric, skeletally mature canine pelvic limb pairs (n = 8). METHODS: Pelvic limbs disarticulated at the coxofemoral joint were randomly assigned to the following 1 of 4 groups: (1) limbs had complete transection of the CrCL; (2) limbs had complete transection of the CdCL; (3) limbs had complete transection of both ligaments; and (4) both ligaments were left intact. Participants performed the DT and the TCT and a diagnosis was given based on the DT and on the combination of these tests. RESULTS: DT had a poor sensitivity for correctly identifying CrCL (69%), CdCL (45%), and TCL (26%) rupture, but had a high sensitivity when identifying intact limbs (97%). Specificity for DT was greatest when identifying limbs with CdCL (97%) and TCL (92%) rupture, and the lowest when palpating limbs with CrCL rupture (75%). Combining DT and TCT did not increase sensitivity or specificity values, nor did an increased level of evaluator training. CONCLUSIONS: Independent of evaluator training, the DT alone or combined with the TCT poorly differentiates the cause of stifle instability associated with CrCL, CdCL, and TCL rupture.

Heat generation by two different saw blades used for tibial plateau leveling osteotomies.

During tibial plateau leveling osteotomy (TPLO) the saw blade produces frictional heat. The purpose of this study was to evaluate and compare heat generated by two TPLO blade designs (Slocum Enterprises [SE] and New Generation Devices [NDG]), with or without irrigation, on cadaveric canine tibias. Thirty-six paired tibias were used to continuously measure bone temperatures during osteotomy through both cortices (i.e., the cis and trans cortices). Each pair was assigned to either an irrigation or nonirrigation group during osteotomy, and each tibia within a pair was osteotomized using a different saw blade design. Saw blade temperatures were recorded and temperatures were compared for all combinations of blade type, cortex, and irrigation. In the cis cortex group, the SE blade generated more bone heat than the NGD blade (P=0.0258). Significant differences in temperature generation between saw blade types were seen only when the osteotomy site was not irrigated (P=0.0156). For all variables measured, bone and saw blade temperature generation was lower with irrigation (P<0.05). None of the osteotomies performed with either saw blade produced a critical duration of damaging temperature ranges in this study. Although saw blade design and irrigation influence heat generation during the TPLO, the potential for bone thermal damage during TPLO is low. The use of the NGD blade with irrigation is recommended.

Effects of 6% hetastarch (600/0.75) or lactated Ringer's solution on hemostatic variables and clinical bleeding in healthy dogs anesthetized for orthopedic surgery.

OBJECTIVE: To evaluate and compare hemostatic variables and clinical bleeding following the administration of 6% hetastarch (600/0.75) or lactated Ringer's solution (LRS) to dogs anesthetized for orthopedic surgery. STUDY DESIGN: Randomized blinded prospective study. ANIMALS: Fourteen, healthy adult mixed-breed hound dogs of either sex, aged 11-13 months, and weighing 20.8±1.2 kg. METHODS: The dogs were randomly assigned to receive a 10 mL kg(-1) intravenous (i.v.) bolus of either 6% hetastarch (600/0.75) or LRS over 20 minutes followed by a maintenance infusion of LRS (10 mL kg(-1)  hour(-1)) during anesthesia. Before (Baseline) and at 1 and 24 hours after bolus administration, packed cell volume (PCV), total protein concentration (TP), prothrombin time (PT), activated partial thromboplastin time (APTT), von Willebrand's factor antigen concentration (vWF:Ag), factor VIII coagulant activity (F VIII:C), platelet count, platelet aggregation, colloid osmotic pressure (COP) and buccal mucosal bleeding time (BMBT) were measured. In addition a surgeon who was blinded to the treatments assessed bleeding from the incision site during the procedure and at 1 and 24 hours after the bolus administration. RESULTS: Following hetastarch or LRS administration, the PCV and TP decreased significantly 1-hour post-infusion. APTT did not change significantly compared to baseline in either treatment group, but the PT was significantly longer at 1-hour post-infusion than at 24 hours in both groups. No significant change was detected for vWF:Ag, FVIII:C, platelet aggregation or clinical bleeding in either group. The BMBT increased while platelet count decreased significantly at 1-hour post-infusion in both groups. The COP decreased significantly in both treatment groups 1-hour post-infusion but was significantly higher 1-hour post-infusion in the hetastarch group compared to the LRS group. CONCLUSIONS AND CLINICAL RELEVANCE: At the doses administered, both hetastarch and LRS can alter hemostatic variables in healthy dogs. However, in these dogs undergoing orthopedic surgery, neither fluid was associated with increased clinical bleeding.

Potential iatrogenic medial meniscal damage during tibial plateau leveling osteotomy.

OBJECTIVE: To evaluate potential iatrogenic medial meniscal (MM) damage during tibial plateau leveling osteotomy (TPLO) and to establish a safe zone (SZ) for hypodermic needle (HN) identification of the medial aspect of the stifle joint. STUDY DESIGN: Prospective cohort. ANIMALS: Cadaveric canine stifles (n=40). METHODS: HN (20 or 25 G) were inserted through the medial collateral ligament (MCL) of the femorotibial joint and through the SZ insertion points. The medial meniscus was inspected for iatrogenic damage. Statistical comparison of MM damage caused by different needle sizes and insertion sites was performed using Fisher's exact test with significance at P< .05. RESULTS: Twenty-gauge group: 65% of stifles had minor MM damage with MCL insertion compared with 35% of stifles with SZ insertion (P=.0049). Severe MM damage occurred in 25% of stifles with MCL insertion compared with 0% of stifles with SZ insertion (P=.0014). Twenty-five-gauge group: 85% of stifles had minor MM damage with MCL insertion compared with 30% after SZ insertion (P=.0011); however, no severe MM injury was noted. CONCLUSIONS: HN insertion though the MCL can produce iatrogenic damage to the MM. Use of a 25 G HN and SZ site for insertion reduced the frequency and severity of MM damage. CLINICAL RELEVANCE: HN insertion into the medial aspect of the femorotibial joint during TPLO can cause gross iatrogenic MM damage, which may contribute to the incidence and misdiagnosis of latent MM injuries after TPLO.

Surgical treatment of mineralized and nonmineralized supraspinatus tendinopathy in twenty-four dogs.

OBJECTIVE: To report and compare the clinical diagnosis, surgical treatment, histopathologic changes, and outcomes of dogs with mineralized and nonmineralized supraspinatus tendinopathy (ST). STUDY DESIGN: Case series. ANIMALS: Dogs (n=24) with ST. METHODS: Medical records (1995-2006) of dogs with ST that had surgical treatment were reviewed. Results of clinical examination, diagnostic imaging, surgery, histopathology of resected tendon tissue, and outcome were compared between dogs with mineralized and nonmineralized ST. RESULTS: There were 15 dogs with mineralized ST and 9 with nonmineralized ST. Chronic, unilateral, intermittent or waxing-waning lameness, and pain elicited on palpation of the cranial aspect of the shoulder were the most consistent findings. On ultrasonographic or magnetic resonance imaging (MRI) of 35 shoulders, enlargement of the supraspinatus tendon (54%), increased fluid content (63%), and medial displacement of the biceps tendon (60%) were observed. Eleven of 12 dogs with bilateral abnormalities only had unilateral lameness. Surgery was performed in 30 shoulders. Resected tendon specimens had myxomatous degeneration and/or cartilaginous metaplasia in 11 of 13 dogs in the mineralized group and all 9 dogs in the nonmineralized group. Functional outcome after surgery was poor in 3 dogs and good-to-excellent in 16. CONCLUSIONS: Mineralized and nonmineralized ST have many similarities. Although lameness is usually unilateral, the supraspinatus tendon may be affected bilaterally. CLINICAL RELEVANCE: Ultrasonography and MRI are good imaging techniques for detection of ST especially the nonmineralized form. Surgical treatment results in good recovery of limb function. Nonmineralized ST is a recently described disorder in dogs and evaluation of more cases is necessary to determine outcome after surgical or medical treatment.

Arthropathy caused by a lead bullet in a dog.

CASE DESCRIPTION: A 3-year-old spayed female Labrador Retriever was evaluated for progressive lameness of the left forelimb 21 months after being shot in the elbow with a lead bullet. CLINICAL FINDINGS: Physical examination findings were consistent with moderate osteoarthritis of the left elbow joint. Orthogonal radiographic views of the elbow revealed multiple metallic fragments in and around the joint space as well as signs of osteoarthritis. TREATMENT AND OUTCOME: The elbow joint was evaluated arthroscopically. A lead-based bullet fragment was seen in the lateral synovial compartment and removed in multiple pieces. Excess fibrin and synovium were removed, and microfractures were created in exposed subchondral bone to stimulate neovascularization and fibrocartilage formation. In a follow-up telephone conversation 4 months after surgery, the owner reported a marked improvement in the lameness. CLINICAL RELEVANCE: Removal of lead intra-articular foreign bodies may be indicated even if the material is not believed to mechanically interfere with joint motion.

Augmentation of intertransverse process lumbar fusion.

Spinal fusion surgery for alleviation of intractable lower back pain in humans is currently a primary therapeutic technique, with failure rates averaging between 5 to 35%. Implanted and external source-based electrical stimulation devices have been investigated in an attempt to increase osteogenesis at the fusion site in an attempt to reduce spinal fusion failure rates. The purpose of our study was to evaluate the efficacy of two co-processor systems and an additional system with an SIS generation field at 15.8 mA (rms) using biomechanical, dual-energy X-ray absorptiometry (DXA), and histomorphometric analyses, in rabbits following dorsolateral (= posteriolateral [in humans]) spinal fusion. Fifty-six male New Zealand White underwent bilateral lumbar spinal fusion by performing decortication of the transverse processes of lumbar vertebrae four and five with placement of autogenic cancellous bone graft harvested from the ilial wings. Four study groups were designated based on the type of IES device used for stimulation or as a control. Eight weeks after surgery all subjects were sacrificed and the quality and strength of the fusion masses were compared using radiographic, biomechanical, histomorphometry, and qualitative histological evaluation. While some variation existed within and between groups, Group 2 showed a significant improvement in all parameters measured as compared to the control group (P < 0.05). The use of adjunct non-invasive surface IES for improving bony fusion rates for patients undergoing lumbar spinal fusion is supported by this study.

Prevalence of cranial cruciate ligament rupture in a population of dogs with lameness previously attributed to hip dysplasia: 369 cases (1994-2003).

OBJECTIVE: To determine the prevalence of cranial cruciate ligament rupture (CCLR) in dogs with lameness previously attributed to canine hip dysplasia (CHD). DESIGN: Retrospective study. ANIMALS: 369 client-owned dogs. PROCEDURES: Hospital medical records from 1994 to 2003 were reviewed for dogs in which the referring veterinarian had diagnosed hip dysplasia or hip pain. Dogs were designated as having hind limb lameness because of partial or complete CCLR or CHD. RESULTS: 8% of dogs were sexually intact females, 43% were spayed females, 14% were sexually intact males, and 35% were castrated males. Mean age was 3.8 years (range, 3 months to 15 years). The most common breeds were the Labrador Retriever (21%), German Shepherd Dog (13%), and Golden Retriever (11%). The prevalence of CCLR as the cause of hind limb lameness was 32% (95% confidence interval, 27.2% to 36.8%). The distribution of CCLR among hind limbs was left (29%), right (28%), and bilateral (43%). Of 119 dogs with CCLR, 94% had concurrent radiographic signs of CHD, 92% had stifle joint effusion, and 81% had a cranial drawer sign. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of the high prevalence of CCLR in dogs referred for lameness because of CHD, it is important to exclude other sources of stifle joint disease before making recommendations for treatment of CHD.

Synovial T-cell lymphoma of the stifle in a dog.

A 6-year-old, 43-kg, spayed female rottweiler was presented for a 1-month history of progressive, left hind-limb lameness. Upon physical examination, a cranial drawer sign and joint distention were present in the left stifle. Radiographically, the stifle had evidence of effusion, remodeling of the patella, and an enlarged popliteal lymph node. Marked synovial thickening and an intact cranial cruciate ligament were noted during surgery. Despite finding a nonspecific, mixed inflammatory response on joint fluid cytopathology, histopathology demonstrated T-cell lymphoma of the synovium. Lameness may be the sole presenting clinical sign in canine lymphoma.