Japan Small Animal Medical Center

This prospective study aimed to report femoro-patellar joint congruency assessed by computed tomography (CT) following block recession trochleoplasty (BRT) and tibial tuberosity transposition (TTT) in cats with medial patellar luxation (MPL).Six cats (median age 56 months; range 15-86 months) with 10 stifles with grades 2 (n = 5) and 3 (n = 5) MPL were enrolled. Standard BRT and TTT were performed. Standardized CT measurements of the trochlear groove (width, depth, and area) and patella (recessed area) were performed preoperatively (T0), immediately postoperatively (T1), and at a 6-week re-examination (T6) with stifles in extended and flexed positions.Mean femoral trochlear area and depth increased significantly between T0-T1, T1-T6, and T0-T6 (p < 0.05). Mean recessed patellar area significantly increased between all time points when the stifle was flexed and between T0-T1 and T0-T6 when the stifle was extended (p < 0.05). Mean trochlear width increased significantly between T0 and T6 (p < 0.05). No cats had MPL recurrence at the 6-week follow-up.Block recession trochleoplasty combined with TTT improved patellar congruency immediately after surgery, with further improvement documented at the 6-week postoperative re-examination.

BackgroundLimb amputation is a standard surgical procedure in dogs for the management of limb tumors such as osteosarcoma, soft tissue sarcoma, and malignant peripheral nerve sheath tumors. While many dogs adapt functionally to limb loss, altered biomechanics, compensatory strain on remaining limbs, and impaired mobility can negatively impact their quality of life. Physiotherapy is recommended to facilitate post-amputation recovery; however, objective data on its effectiveness in dogs remain limited. Furthermore, when radiotherapy is required postoperatively, the necessary daily anaesthesia and cage rest can exacerbate functional decline due to restricted activity. The impact of physiotherapy on gait function in a forelimb-amputee dog undergoing concurrent radiotherapy is described in this report.Case presentationA 14-year-old neutered male Toy Manchester Terrier underwent left forelimb amputation following the diagnosis of a malignant peripheral nerve sheath tumor at the C6–T1 spinal level. One month postoperatively, the dog began a three-week course of radiotherapy that required daily anaesthesia and prolonged cage rest, raising concerns about mobility deterioration. To mitigate these effects, a structured physiotherapy program was implemented. The program consisted of daily 30-minute sessions focusing on range of motion exercises, balance and proprioception training, weave pole exercises, and cavaletti rail walking. Gait analysis was performed on the first and last days of the physiotherapy program (pre- and post-physiotherapy) using a two-dimensional kinematic system.After three weeks of physiotherapy, a reduction in vertical head movement was observed (48.3 cm to 34.5 cm), indicating improved gait stability. Additionally, shoulder and elbow extension showed an increase during the loading response phase, which is crucial for weight-bearing and locomotor efficiency.ConclusionsThis case provides objective evidence supporting the potential benefits of physiotherapy in enhancing gait function and stability in dogs following a forelimb amputation, even when physical activity is restricted due to radiotherapy-related hospitalization. The findings suggest that integrating physiotherapy into post-amputation care may mitigate functional decline associated with prolonged cage rest and optimize recovery. Further studies are needed to investigate the long-term benefits of physiotherapy and effects of physiotherapy on compensatory musculoskeletal adaptations in amputee dogs.

Canine invasive urothelial carcinoma (iUC) is a fatal malignant neoplasm that closely resembles human muscle-invasive bladder cancer in terms of histopathological features, molecular alterations, and clinical behavior. These similarities suggest that canine iUC represents a valuable spontaneous model for studying human bladder cancer. Tumor microenvironment (TME) plays a crucial role in tumor progression. Tumor-derived lactic acid has been implicated in the suppression of antitumor immunity and the promotion of tumor growth by altering the metabolic status of immune cells within the TME. However, the interaction between tumor metabolism and immune cells in the TME remains unclear in dogs. This study reanalyzed previously reported RNA-seq data to investigate the mechanisms underlying enhanced glycolysis in canine iUC. ERBB2 overexpression was found to induce AKT phosphorylation and increase extracellular lactic acid levels in vitro, activating the ERBB2-AKT-glycolysis axis and upregulating monocarboxylate transporter 4 (MCT4). MCT4 knockdown by RNA interference or pharmacological inhibition with diclofenac reduced lactic acid levels in the culture supernatant. Furthermore, MCT4 expression in canine iUC tissues was positively correlated with infiltrating regulatory T cell (Treg) counts. Functional studies revealed that lactic acid promoted Treg differentiation and suppressed IFN-γ production by effector T cells. These findings indicate that MCT4 mediates lactic acid efflux from glycolytic tumor cells, contributing to the suppression of antitumor immunity. Targeting tumor metabolism through MCT4 inhibition may represent a promising therapeutic strategy for canine iUC. Therefore, insights from the metabolic and immunological landscape of canine iUC may inform the development of translational therapies for both veterinary and human oncology.

ObjectivesTo identify dogs at risk of developing pivot-shift (PS) following tibial-plateau-leveling-osteotomy (TPLO) using a rotational-instability-test (RI-test), describe a combination of a monofilament anti-rotational suture (ARS) with TPLO and assess this technique for feasibility, compare post-operative PS-incidence in dogs receiving a standard TPLO (TPLO-only) or a TPLO with ARS (TPLO+ARS), and design a novel TPLO-plate facilitating ARS-anchoring (TPLO/ARS-plate).Study designIn this clinical pilot trial on 85 client-owned dogs and instrumentation design study, the RI-test and ARS-placement-technique were described and performed. Reporting included: anesthesia and surgery times, bone-healing, post-TPLO-PS-incidence, follow-up and complications. Significance was set as p ≤ 0.05. Comprehensive engineering of a novel TPLO plate was performed.ResultsBetween TPLO-only (n = 57) and TPLO+ARS (n = 28) groups, significant differences were found for surgery time (p = 0.01), anesthesia time (p<0.001) and bone healing scores (p = 0.03), all being longer/higher for TPLO+ARS. PS-incidence was 2/57 (TPLO-only) and 0/28 (TPLO+ARS) within the first 8 weeks post-surgery (p = 1.00). Medium follow-up was 642 days. Major complications during that time occurred in 2/57 (TPLO-only; infection and implant removal) and 1/28 (TPLO+ARS; infection, PS-development and implant removal) dogs (p = 1.00). A novel TPLO/ARS-plate was designed.ConclusionPost-TPLO-PS might be reduced following ARS placement. Additional studies are indicated to validate and refine the RI-test and assess the novel TPLO/ARS-plate in the clinical setting.

ABSTRACTHuman enteropathy‐associated T‐cell lymphoma (EATL) is a rare primary aggressive intestinal T‐cell lymphoma associated with celiac disease and is considered to be a neoplasm of intraepithelial lymphocytes (IELs) with an innate lymphoid cell (ILC)‐like immunophenotype. The lack of an animal model has delayed the elucidation of its pathogenesis. In dogs, the histopathological and immunophenotypic features of intestinal large T‐cell lymphoma (ILTCL) are similar to EATL; however, its cell of origin remains unclear. We herein performed detailed immunophenotyping, an RNA expression analysis of selected genes, and gene mutation analysis of 54 cases of ILTCL, including 27 with fresh frozen samples available and 21 of intestinal small T‐cell lymphoma (ISTCL) in dogs. Canine ILTCL was characterised by the expression of cytotoxic granules (53/54) and frequent absence of CD4/CD8 (26/27) and T‐cell receptors (14/27). The mRNA expression of CD103 (25/35) and NKp46 (15/35) was detected in ILTCL by RNA in situ hybridisation. The gene mutation analysis showed mutations in NFKBIA (ILTCL, 31/54; ISTCL, 10/21), including truncating mutations (ILTCL, 11/54; ISTCL, 3/21). Mutations in STAT3 SH2 were less frequent (ILTCL, 13/54; ISTCL, 3/21) and the hotspot JAK1 mutation of human EATL was not detected. Immunohistochemistry for p‐Stat3 showed STAT3 pathway activation in ILTCL cases. These results suggest that canine ILTCL is also a neoplasm of IEL with an ILC‐like immunophenotype and STAT3 pathway activation, and loss‐of‐function mutations in NF‐κB pathway inhibitors are associated with its neoplastic changes. Therefore, canine ILTCL has potential as a valuable model for investigating the pathogenesis of EATL.

Abstract Background: Limb amputation is a standard surgical procedure in dogs for the management of limb tumors such as osteosarcoma, soft tissue sarcoma, and malignant peripheral nerve sheath tumors. While many dogs adapt functionally to limb loss, altered biomechanics, compensatory strain on remaining limbs, and impaired mobility can negatively impact their quality of life. Physiotherapy is recommended to facilitate post-amputation recovery; however, objective data on its effectiveness in dogs remain limited. Furthermore, when radiotherapy is required postoperatively, the necessary daily anaesthesia and cage rest can exacerbate functional decline due to restricted activity. The impact of physiotherapy on gait function in a forelimb-amputee dog undergoing concurrent radiotherapy is described in this report. Case presentation: A 14-year-old neutered male Toy Manchester Terrier underwent left forelimb amputation following the diagnosis of a malignant peripheral nerve sheath tumor at the C6–T1 spinal level. One month postoperatively, the dog began a three-week course of radiotherapy that required daily anaesthesia and prolonged cage rest, raising concerns about mobility deterioration. To mitigate these effects, a structured physiotherapy program was implemented. The program consisted of daily 30-minute sessions focusing on range of motion exercises, balance and proprioception training, weave pole exercises, and cavaletti rail walking. Gait analysis was performed on the first and last days of the physiotherapy program (pre- and post-physiotherapy) using a two-dimensional kinematic system. After three weeks of physiotherapy, a significant reduction in vertical head movement was observed (48.3 cm to 34.5 cm, p &lt; 0.05), indicating improved gait stability. Additionally, shoulder and elbow extension increased during the loading response phase, which is crucial for weight-bearing and locomotor efficiency. Conclusions: This case provides objective evidence supporting the potential benefits of physiotherapy in enhancing gait function and stability in dogs following a forelimb amputation, even when physical activity is restricted due to radiotherapy-related hospitalization. The findings suggest that integrating physiotherapy into post-amputation care may mitigate functional decline associated with prolonged cage rest and optimize recovery. Further studies are needed to investigate the long-term benefits of physiotherapy and effects of physiotherapy on compensatory musculoskeletal adaptations in amputee dogs.

Spontaneous pneumothorax in dogs is predominantly caused by the rupture of air-filled lesions, such as bullae or blebs. The efficacy of Computed Tomography (CT) in detecting these lesions has been deemed limited due to its reportedly low sensitivity. This retrospective, cross-sectional study investigates the utility of CT in eight dogs diagnosed with recurrent pneumothorax, all of which had surgical confirmation of the cause of the pneumothorax. Thoracic radiographs were obtained before and the day following the CT studies. Initially, a CT study was conducted without positive pressure ventilation (pre-PPV CT). Subsequent CT studies were performed post-evacuation of pneumothorax and with positive pressure ventilation of 15 cmH2O until lung atelectasis was resolved (post-PPV CT). The pre-PPV CT and post-PPV CT images were anonymized and reviewed by two board-certified radiologists. The presence and morphology of air-filled lesions were evaluated on all images. Surgical findings were recorded and compared to the CT findings. Air-filled lesions were detected in 5 out of 8 dogs in the pre-PPV CT studies and in all 8 dogs in the post-PPV CT studies. The CT findings of air-filled lesions were consistent with surgical findings. None of the dogs showed increased severity of pneumothorax in radiographs taken the day following the CT studies. The study concludes that the resolution of lung atelectasis by evacuation of pneumothorax and positive pressure ventilation during CT studies is feasible and enhances the detection of air-filled lesions in dogs with recurrent spontaneous pneumothorax. This could potentially aid in improving surgical planning.

Although chemotherapy using CHOP-based protocol induces remission in most cases of canine multicentric high-grade B-cell lymphoma (mhBCL), some cases develop early relapse during the first induction protocol. In this study, we examined the gene expression profiles of canine mhBCL before chemotherapy and investigated their associations with early relapse during the first whole CHOP-based protocol. Twenty-five cases of mhBCL treated with CHOP-based protocol as first induction chemotherapy were included in this study. Sixteen cases completed the first whole CHOP-based protocol without relapse (S-group), and nine developed relapse during the chemotherapy (R-group). RNA-seq was performed on samples from neoplastic lymph nodes. Differentially expressed genes (DEGs) were extracted by the comparison of gene expression profiles between S- and R-groups, and the differences in the expression levels of these genes were validated by RT-qPCR. Extracted 179 DEGs included the genes related to chemokine CC motif ligand, T-cell receptor signaling pathway, and PD-L1 expression and PD-1 checkpoint pathway. We focused on chemokine CC motif ligand, and CCL4 was confirmed to be significantly downregulated in the R-group (P=0.039). We also focused on the genes related to T-cell signaling pathway, and CD3E (P=0.039), ITK (P=0.023), and LAT (P=0.023) genes were confirmed to be significantly upregulated in the R-group. The current results suggest that both changes in tumor cells and the interactions between tumor cells and immune cells are associated with the efficacy of the chemotherapy for first remission induction.

Abstract Background &amp; ObjectivesThe TactiFlexTMSE irrigation catheter installs a laser-cut flexible tip with a thermocouple embedded 0.3mm from the tip, being used with temperature-control mode. We aimed to elucidate a safer method to enlarge the lesion size using this catheter.MethodsRF-applications were performed at a range of powers (35W, 40W, and 45W), CFs (10g/20g), and durations (60s, 120s, and 180s) using perpendicular/parallel catheter orientation with normal saline irrigation (NS-irrigation) and Half NS-irrigation (HNS-irrigation) in an ex-vivo model (Step 1). Further, similar RF-applications of 35W/40W/45W for 60s/120s/180 in NS-irrigation and 35W/40W for 60s/120s/180s in HNS-irrigation) were performed in 4 swine (Step 2). Lesion characteristics and the incidence of steam-pops were assessed.ResultsIn this ex-vivo experiment, 47(16.3%) steam-pops (13 in NS-irrigation vs 34 in HNS-irrigation, p=0.001) were observed in 288 lesions. In NS-irrigation group, the most aggressive setting (45W/180s, n=7/13, 54%) played a large part of steam-pop occurrence. Lesion size proportionally increased with longer ablation duration, but not with HNS-irrigation. The optimal cut-off of %impedance-drop to predict steam-pops was 20% with the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 78.3%, 80.6%, 43.4%, and 95.1%, respectively. In the in-vivo experiment, steam-pops were not observed with NS-irrigation (n=0/35), but were with HNS-irrigation (6/21, 29%). Lesion size proportionally increased with longer ablation duration, but not with HNS-irrigation partially because of the higher incidence of temperature-guard use (p=0.07). The optimal cut-off of %impedance-drop to predict steam-pops was 24% with the sensitivity= 83.0%, specificity=52.0%, PPV= 17.2%, and NPV= 96.3%, respectively, but 20% may be used with a safety margin.ConclusionsAlthough this novel catheter is generally safe, increasing ablation duration instead of using HNS-irrigation may be recommended for larger lesions.