Single-Nuclei Multiome (ATAC + Gene Expression) Sequencing of a Primary Canine Osteosarcoma Elucidates Intra-Tumoral Heterogeneity and Characterizes the Tumor Microenvironment.

Osteosarcoma (OSA) is a highly aggressive bone tumor primarily affecting pediatric or adolescent humans and large-breed dogs. Canine OSA shares striking similarities with its human counterpart, making it an invaluable translational model for uncovering the disease's complexities and developing novel therapeutic strategies. Tumor heterogeneity, a hallmark of OSA, poses significant challenges to effective treatment due to the evolution of diverse cell populations that influence tumor growth, metastasis, and resistance to therapies. In this study, we apply single-nuclei multiome sequencing, encompassing ATAC (Assay for Transposase-Accessible Chromatin) and GEX (Gene Expression, or RNA) sequencing, to a treatment-naïve primary canine osteosarcoma. This comprehensive approach reveals the complexity of the tumor microenvironment by simultaneously capturing the transcriptomic and epigenomic profiles within the same nucleus. Furthermore, these results are analyzed in conjunction with bulk RNA sequencing and differential analysis of the same tumor and patient-matched normal bone. By delving into the intricacies of OSA at this unprecedented level of detail, we aim to unravel the underlying mechanisms driving intra-tumoral heterogeneity, opening new avenues for therapeutic interventions in both human and canine patients. This study pioneers an approach that is broadly applicable, while demonstrating significant heterogeneity in the context of a single individual's tumor.

Outcomes and clinical features associated with surgically excised canine salivary gland carcinoma: A multi-institutional, retrospective, Veterinary Society of Surgical Oncology study.

OBJECTIVE: The objective of this study was to describe the clinical features, prognostic factors, and outcomes in dogs with surgically treated salivary gland carcinoma. STUDY DESIGN: Multi-institutional retrospective case series. ANIMALS: Seventy-two client-owned dogs from 16 institutions with surgically excised salivary gland carcinoma. METHODS: Medical records of dogs undergoing sialoadenectomy from January 1, 2000 to January 1, 2020 were reviewed for signalment, clinical signs, preoperative staging results, preoperative mass evaluation, complications, histopathologic diagnosis, local recurrence, metastatic disease, and survival times. Survival functions were estimated using the Kaplan-Meier estimator. Factors related to survival were individually tested using the log-rank test. RESULTS: The overall median survival time (MST) associated with salivary carcinoma was 1886 days. Local recurrence occurred in 29/69 (42%) dogs with an overall disease-free interval (DFI) of 191 days. Metastatic disease occurred in 22/69 (31.9%) dogs, with an overall DFI of 299 days. Lymph node metastasis was present at the time of surgery in 11/38 (28.9%) dogs in which lymphadenectomy was performed at the time of surgery; these dogs had a shorter DFI at 98 days (P = .03) and MST at 248 days (P < .001). CONCLUSION: The prognosis for dogs with salivary gland carcinoma treated surgically was more favorable than previously reported. Nodal metastasis was a negative prognostic factor for canine salivary gland carcinoma. CLINICAL SIGNIFICANCE: Surgical intervention should be considered for dogs with salivary carcinoma.

Staphylectomy in nonbrachycephalic dogs: A retrospective study of 27 cases.

Objective: To report the outcomes and complications associated with staphylectomy in nonbrachycephalic dogs. Animal: Twenty-seven nonbrachycephalic dogs with elongated soft palates and undergoing staphylectomy. Procedure: Retrospective study. Results: Increased upper airway noise (70.4%) and dyspnea (44.4%) were the most common presenting clinical signs. Concurrent upper airway abnormalities found in the study population included laryngeal collapse (25.9%) and laryngeal paralysis (14.8%). The most common staphylectomy technique used in this study was sharp excision (66.7%) with sutured oral and nasal mucosal apposition. The dogs in this study had an overall minor postoperative complication rate of 33.3%, with regurgitation/vomiting (11.1%) and coughing (11.1%) occurring most commonly. No dog required supplemental oxygen therapy or temporary tracheostomy. Conclusion: Staphylectomy was well-tolerated in nonbrachycephalic dogs and was associated with a relatively low rate of complications. Concurrent airway abnormalities were common among nonbrachycephalic dogs with elongated soft palates, similar to brachycephalic dogs. Clinical relevance: Clinicians should be aware that elongated soft palate can occur in nonbrachycephalic dogs, and surgical correction can be achieved with rare major or catastrophic complications.

Staphylectomie chez des chiens non-brachycéphales : une étude rétrospective de 27 cas. Objectif: Rapporter les résultats et les complications associés à la staphylectomie chez des chiens non-brachycéphales. Animal: Vingt-sept chiens non-brachycéphales au palais mou allongé et subissant une staphylectomie. Procédure: Étude rétrospective. Résultats: L'augmentation du bruit des voies respiratoires supérieures (70,4 %) et la dyspnée (44,4 %) étaient les signes cliniques les plus fréquents. Les anomalies concomitantes des voies respiratoires supérieures trouvées dans la population étudiée comprenaient un collapsus laryngé (25,9 %) et une paralysie laryngée (14,8 %). La technique de staphylectomie la plus couramment utilisée dans cette étude était l'exérèse fine (66,7 %) avec apposition suturée des muqueuses buccale et nasale. Les chiens de cette étude présentaient un taux global de complications postopératoires mineures de 33,3 %, les régurgitations/vomissements (11,1 %) et la toux (11,1 %) étant les plus fréquents. Aucun chien n'a eu besoin d'une oxygénothérapie supplémentaire ou d'une trachéotomie temporaire. Conclusion: La staphylectomie a été bien tolérée chez les chiens non-brachycéphales et a été associée à un taux relativement faible de complications. Les anomalies concomitantes des voies respiratoires étaient courantes chez les chiens nonbrachycéphales avec des palais mous allongés, semblables aux chiens brachycéphales. Pertinence clinique: Les cliniciens doivent être conscients qu'un palais mou allongé peut survenir chez les chiens non-brachycéphales et qu'une correction chirurgicale peut être obtenue avec de rares complications majeures ou catastrophiques.(Traduit par Dr Serge Messier).

Ex vivo comparison of different thoracoabdominal stapler sizes for typhlectomy in canine cadavers.

OBJECTIVE: To determine the influence of staple size on leakage pressure of typhlectomy sites in canine cadavers. STUDY DESIGN: Randomized, experimental cadaveric study. ANIMALS: Twenty-four fresh canine cadavers. METHODS: Ileocecocolic segments were exteriorized following right paracostal laparotomy after euthanasia. Cecal base length and wall thickness were measured. Each cecum was randomly assigned to 1 of 3 groups (TA 30 V3 2.5 mm, TA 60 3.5 mm, and TA 60 4.8 mm). The cecal base was stapled and the cecum was removed. A 10 cm segment including the stapled cecal excision site was tested for initial leak pressure. RESULTS: The mean ± standard deviation body weights across the groups were 18.7 ± 6.1 kg, 16.2 ± 7.5 kg, and 14.2 ± 5.5 kg for the TA 30 V3 2.5 mm, TA 60 3.5 mm, and TA 60 4.8 mm groups, respectively (P = .48). There were no differences for mean cecal base length or wall thickness. Mean initial leak pressure (ILP) across groups was 182 ± 111 mmHg (TA 30 V3 2.5 mm), 112 ± 57 mmHg (TA 60 3.5 mm), and 77 ± 60 mmHg (TA 60 4.8 mm) (P = .78). CONCLUSION: Each stapler size that was evaluated resulted in a mean ILP in excess of typical intraluminal pressures under normal circumstances. There were no differences among groups. CLINICAL SIGNIFICANCE: The results of this cadaveric study support the use of any of the stapler sizes evaluated in similarly sized dogs. A prospective study is needed to be able to correlate stapler size and clinical outcome.

Partial parotid sialoadenectomy in a horse with parotid ductal carcinoma: Surgical description and case report.

OBJECTIVES: To describe the surgical findings, histopathological features, and long-term outcome for a horse with parotid salivary carcinoma. STUDY DESIGN: Case report ANIMALS: Twelve year old American Quarter Horse gelding. METHODS: The gelding was presented for a 10 × 10 cm swelling below the base of the right ear. Ultrasonographic examination revealed a mass involving the right parotid salivary gland. Incisional biopsy was consistent with parotid carcinoma. The tumor was marginally excised. The lateral wall of the guttural pouch was excised with the mass and was reconstructed with a porcine small intestinal submucosal (SIS) sheet. Cisplatin beads were implanted in the wound bed prior to closure. Firocoxib (0.1 mg/kg orally, daily, every 24 h) treatment was initiated. RESULTS: Postoperative complications included right-sided facial nerve paralysis, difficulty with deglutition of fibrous feeds, and surgical site dehiscence. Wound healing was achieved by second intention. Partial improvement in nerve function was observed within the first 6 months. At 12 months postparotidectomy, no sign of tumor reoccurrence or metastatic disease was present, and the gelding returned to work. CONCLUSION: Partial parotid sialoadenectomy was performed with a favorable long-term outcome. Regional anatomic knowledge is crucial.

Predictive ability of fine-needle aspirate cytology for incompletely resected mast cell tumor surgical sites.

The goal of this study was to evaluate whether fine-needle aspirate cytology of a previous surgical site was predictive of recurrence for incompletely excised mast cell tumors (MCTs). Electronic medical records were searched for dogs diagnosed with MCTs; those with histologically confirmed, incompletely resected MCTs evaluated by scar aspiration cytology within 60 days after surgery were included for analysis. Variables were compared between groups using Fisher's exact test and logistic regression. Twenty-nine cutaneous and 7 subcutaneous tumors were evaluated. Local recurrence, confirmed by either histopathology or cytology, occurred in 13.8% of cases. No significant differences were identified for any variables other than surgical site cytology status. The negative predictive value of surgical site aspirate cytology without residual mast cell tumor was 93.5%, with an overall predictive accuracy of 88.9%. For the dogs evaluated in this report, surgical site aspiration cytology was predictive of local disease control for incompletely resected MCTs.

Capacité prédictive de la cytologie d'aspiration à l'aiguille fine de sites de chirurgie de résection incomplète de mastocytomes. L'objectif de la présente étude était d'évaluer si la cytologie d'aspiration à l'aiguille fine d'un site chirurgical antérieur permettait de prédire une récurrence lors de l'excision incomplète d'un mastocytome (MCT). Les dossiers médicaux électroniques furent examinés pour trouver des chiens avec un diagnostic de MCT; ceux avec confirmation histologique d'un MCT avec résection incomplète évaluée par cytologie d'une aspiration de la cicatrice en dedans de 60 jours après la chirurgie furent inclus pour analyse. Les variables furent comparées entre les groupes en utilisant le test exact de Fisher et une régression logistique. Vingt-neuf tumeurs cutanées et sept tumeurs sous-cutanées furent évaluées. Une récurrence locale, confirmée par histopathologie ou cytologie, est survenue dans 13,8 % des cas. Aucune différence significative ne fut détectée pour les différentes variables autres que le statut de la cytologie du site chirurgical. La valeur prédictive négative de la cytologie d'une aspiration du site chirurgical sans cellule résiduelle du mastocytome était de 93,5 % avec une précision prédictive globale de 88,9 %. Pour les chiens examinés dans cette étude, la cytologie d'une aspiration du site chirurgical était prédictive d'une maîtrise locale de la maladie lors de résection incomplète d'un MCT.(Traduit par Dr Serge Messier).

The effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium in a simulated tumor model.

OBJECTIVE: To determine the effect of surgery on lymphoscintigraphy drainage patterns from the canine brachium. STUDY DESIGN: Experimental study. ANIMALS: Eight healthy research beagles. METHODS: A predefined area of skin measuring 2 × 1.5 cm in dimension was designated on either the right or left brachium. Preoperative lymphoscintigraphy was performed with technetium sulfur colloid injected into the subcutaneous tissues around the predefined anatomic location in a four-quadrant technique. Dogs underwent surgery for excision of the predefined area of skin, subcutis, and fascia of the lateral head of the triceps muscle with 1-cm margins. Eighteen days after surgery, lymphoscintigraphy was again performed with technetium sulfur colloid injected into the subcutaneous tissues around the surgical scar in a four-quadrant technique. RESULTS: Sentinel lymph nodes were identified in eight of eight dogs preoperatively and in eight of eight dogs postoperatively. Agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was identified as complete in four of eight dogs and partial in four of eight dogs. Sentinel lymph node identification occurred immediately in three of eight dogs preoperatively and in eight of eight dogs postoperatively. CONCLUSION: Sentinel lymph node identification occurred faster postoperatively. Agreement or partial agreement between the results of the preoperative and postoperative lymphoscintigraphy studies was observed in eight of eight dogs. CLINICAL SIGNIFICANCE: Surgery appears to have an effect on lymphoscintigraphy drainage patterns. Additional studies are required to compare preoperative and postoperative sentinel lymph node mapping patterns in tumor-bearing dogs. However, this study provides preliminary information regarding the effect of surgery on sentinel lymph node identification.

Sentinel lymph node detection differs when comparing lymphoscintigraphy to lymphography using water soluble iodinated contrast medium and digital radiography in dogs.

Sentinel lymph node (SLN) mapping by various means has become standard of care in certain types of human cancers and is receiving more attention in veterinary oncology. Current SLN mapping techniques can be costly and often require advanced imaging equipment. The objective of this prospective, method comparison study was to compare an SLN mapping protocol of lymphoscintigraphy to lymphography using water soluble iodinated contrast medium (WIC) and digital radiography for identification of an SLN. Lymphoscintigraphy and lymphography were performed on eight healthy purpose-bred dogs using technetium-99m sulfur colloid and WIC injected into the subcutaneous tissues in a four-quadrant technique around a predefined area of skin on the brachium. Images were obtained using a gamma camera and digital radiography at different time points post-injection. Image sequences were evaluated by one of two American College of Veterinary Radiology board-certified veterinary radiologists. Data obtained were compared between methods using descriptive statistics. An SLN was identified in all dogs with lymphoscintigraphy and seven of eight dogs with lymphography. Agreement between results of the lymphoscintigraphy and lymphography studies was a complete match in three dogs, a partial match in four dogs, and no match in one dog. The SLN detected differed based on the imaging modality used.

Outcomes and prognostic variables associated with central division hepatic lobectomies: 61 dogs.

OBJECTIVE: To determine the outcome and prognostic variables associated with long-term survival and complications in dogs undergoing hepatic lobectomy of the central division. STUDY DESIGN: Multi-institutional retrospective case series. ANIMALS: Sixty-one client-owned dogs with central division masses. METHODS: Medical records of dogs undergoing hepatic lobectomy of the central division from January 1, 2000 to January 1, 2015 were reviewed for signalment, clinical signs, preoperative staging, preoperative cytology or biopsy results, date of procedure, location of mass, surgical technique, whether cholecystectomy or cholecystopexy was performed, complications, histopathologic diagnosis and margin evaluation, date of local recurrence or detection of metastatic disease, and survival. RESULTS: Hilar resection was associated with increased intraoperative and postoperative complications. Intraoperative complications occurred in 29 dogs, with 20 dogs experiencing intraoperative hemorrhage. Nineteen dogs required transfusions. Immediate postoperative complications occurred in 20 dogs. Perioperative mortality rate was 11%, and 2-week mortality rate was 14.7%. The median survival time for dogs with hepatocellular carcinoma (HCC) was not reached. The 1- and 3-year censored survival rates for dogs with HCC was 82.1% and 82.1%, respectively. Margin status did not impact survival time. CONCLUSION: Hepatic lobectomy of the central division was associated with hemorrhage in approximately 33% of dogs, but there was a relatively low perioperative mortality rate. Hepatic lobectomy for HCC resulted in long-term survival, regardless of margin status. CLINICAL SIGNIFICANCE: Surgeons should anticipate the requirement for blood products in dogs that may require hepatic lobectomy of the central division. Long-term survival can be expected after surgical treatment of HCC, regardless of margin status.

Perioperative complications and outcome after surgery for treatment of gastric carcinoma in dogs: A Veterinary Society of Surgical Oncology retrospective study of 40 cases (2004-2018).

OBJECTIVE: To describe the clinical characteristics, perioperative complications, and outcomes in dogs surgically treated for gastric carcinoma. STUDY DESIGN: Multi-institutional retrospective case series. ANIMALS: Forty client-owned dogs with histologically confirmed gastric carcinoma. METHODS: Medical records were reviewed for preoperative diagnostics, surgery, histopathology, postoperative complications, adjuvant chemotherapy, disease progression, and survival. Variables were assessed for associations with outcome by using Cox proportional hazards regression analysis. RESULTS: Surgical treatment included partial gastrectomy (28 dogs), Billroth I (9 dogs), subtotal gastrectomy (2 dogs), and submucosal resection (1 dog). Major postoperative complications occurred in 8 of 40 dogs, including septic peritonitis secondary to dehiscence in 4 dogs. The median progression free interval was 54 days, and the median survival time (MST) was 178 days (range, 1-1902). According to multivariable analysis results, experiencing an intraoperative complication was associated with an increased risk of death (hazard ratio [HR] 3.5, 95% CI 1.1-9.8, P = .005), and administration of adjuvant chemotherapy correlated with an improved survival (HR 0.4, 95% CI 0.2-0.9, P = .03). CONCLUSION: In this population of dogs, MST exceeded historically reported data, major postoperative complication rates were comparable to established literature, and administration of adjuvant chemotherapy was associated with improved survival. CLINICAL SIGNIFICANCE: Results from this study may be used to counsel owners more accurately regarding prognosis for dogs undergoing surgical excision for gastric carcinoma.

Sentinel lymph node mapping of the canine anal sac using lymphoscintigraphy: A pilot study.

Sentinel lymph node mapping and biopsy are important parts of oncologic staging in human medicine. Sentinel lymph node mapping enables identification of the first lymph node to receive lymphatic drainage while avoiding unnecessary lymph node dissection. Anal sac adenocarcinoma is the most common malignant neoplasm of the canine perineal area. For dogs with anal sac adenocarcinoma, lympadenectomy and metastasis to the iliosacral lymphocentrum are negative prognostics indicators. The objectives of this prospective, two by two, crossover pilot study were to establish the feasibility of lymphoscintigraphy using Technetium-99 sulfur colloid of the canine anal sac of healthy dogs, compare two injection techniques, and the time for identification of sentinel lymph nodes using each technique. We hypothesized that both intramural and perimural injections of the canine anal sac would identify similar sentinel lymph node drainage. The sentinel lymph node was identified in all dogs using either technique. Intramural injection of the canine anal sac showed radiopharmaceutical uptake faster than perimural injection technique (P = 0.040). There was concordance between intramual and perimural techniques for the sentinel lymph node identified in 50% of cases. A sacral lymph node was identified as sentinel in three of eight dogs (37.5%). Lymphoscintigraphy of the canine anal sac is safe and feasible in normal dogs; however, the method of injection technique seems to have a significant effect on the sentinel lymph node identified.

Partial splenectomy for incidentally detected non-ruptured splenic lesions in dogs: 18 cases (2004-2018).

The objective of this retrospective study was to describe the outcome and incidence of splenic malignancy in 18 dogs undergoing partial splenectomy for incidentally detected, non-ruptured splenic lesions. Incidence of splenic malignancy in the present study was 5.6% [95% confidence interval (CI): 0.14% to 27.65%]. Median diameter of splenic nodules was 2 cm (range: 1.5 to 4 cm). Splenic hemangiosarcoma was diagnosed in 1 dog, while the remaining 17 dogs had benign splenic lesions. There was a higher incidence of non-splenic malignancy (50%) than splenic malignancy (5.6%) in the study population. Overall median survival time after surgery was 300 days (range: 4 to 1332 days). Median survival time in dogs with malignant disease (splenic and non-splenic) was 67 days (range: 4 to 425 days) and for non-malignant disease was 727 days (range: 8 to 1332 days). In conclusion, partial splenectomy may be appropriate for small, incidental non-ruptured splenic lesions in dogs.

Splénectomie partielle pour des lésions spléniques non-rupturées détectées de manière fortuite chez des chiens : 18 cas (2004­2018). L'objectif de cette étude rétrospective était de décrire l'issue et la fréquence de malignité splénique chez 18 chiens soumis à une splénectomie partielle pour des lésions spléniques non-rupturées détectées de manière fortuite. La fréquence de malignité splénique dans la présente étude était de 5,6 % [intervalle de confiance de 95 % (CI) : 0,14 % à 27,65 %]. Le diamètre médian des nodules spléniques était de 2 cm (écart : 1,5 à 4 cm). Un hémangiosarcome splénique fut diagnostiqué chez un chien, alors que les 17 autres chiens avaient des lésions spléniques bénignes. Il y avait une plus grande fréquence de malignité non-splénique (50 %) que de malignité splénique (5,6 %) dans la population étudiée. Globalement, le temps de survie médian après la chirurgie était de 300 jours (écart : 4 à 1332 jours). Le temps de survie médian chez les chiens avec une condition maligne (splénique et non-splénique) était de 67 jours (écart : 4 à 425 jours) et pour ceux avec une condition non-maligne il était de 727 jours (écart : 8 à 1332 jours). En conclusion, une splénectomie partielle peut être appropriée pour des petites lésions spléniques secondaires non-rupturées.(Traduit par Dr Serge Messier).

Total prostatectomy as a treatment for prostatic carcinoma in 25 dogs.

OBJECTIVE: To describe the complications and outcome after total prostatectomy in dogs with histologically confirmed prostatic carcinoma. STUDY DESIGN: Multi-institutional retrospective case series. ANIMALS: 25 client-owned dogs. METHODS: Medical records of dogs undergoing total prostatectomy were reviewed from 2004 to 2016. Data retrieved included signalment, presenting signs, preoperative clinical findings, laboratory data, diagnostic imaging, surgical technique, histologic diagnosis, postoperative complications, occurrence of postoperative metastasis, and survival. RESULTS: Twenty-five dogs underwent total prostatectomy for prostatic carcinoma. Urinary anastomotic techniques included urethrourethral anastomosis in 14 dogs, cystourethral anastomosis in 9 dogs, ureterocolonic anastomosis in 1 dog, and anastomosis between the bladder neck and penile urethra in 1 dog. All dogs survived to discharge. Fifteen dogs were diagnosed with transitional cell carcinoma, 8 dogs with prostatic adenocarcinoma, 1 with prostatic cystadenocarcinoma, and 1 with an undifferentiated carcinoma. Permanent postoperative urinary incontinence was present in 8 of 23 dogs. The median survival time was shorter in dogs with extracapsular tumor extension compared with those with intracapsular tumors. The overall median survival time was 231 days (range, 24-1255), with 1- and 2-year survival rates equal to 32% and 12%, respectively. CONCLUSION AND CLINICAL SIGNIFICANCE: Total prostatectomy, combined with adjunct therapies, prolongs survival and lowers complication rates compared to previous reports of dogs with prostatic carcinoma. It should be noted, however, that case selection likely played a significant role in postoperative outcome.

Agreement Between Cytology and Histopathology for Regional Lymph Node Metastasis in Dogs With Melanocytic Neoplasms.

Melanocytic neoplasms are common in dogs and frequently occur within the oral cavity or in haired skin. The behavior of melanocytic neoplasms is variable and depends on tumor location, size, and histopathologic features. This study compared cytopathology and histopathology of 32 lymph nodes from 27 dogs diagnosed with melanocytic neoplasms. Agreement between the original cytology report, cytology slide review, original histopathology report, and histopathology slide review was determined for each lymph node. A subset of lymph nodes was subjected to immunohistochemistry (Melan-A) and additional histochemical stains/techniques (Prussian blue, bleach) to assist in differentiation of melanocytes and melanophages. Agreement ranged from slight to fair for each of the variables evaluated with weighted kappa (κw) or kappa (κ) analysis (original cytology vs cytology review κw = 0.24; original cytology vs original histopathology κw = 0.007; original cytology vs histopathology review κw = 0.23; cytology review vs original histopathology κw = 0.008; cytology review vs histopathology review κw = 0.006; and original histopathology vs histopathology review κ = 0.18). The diagnoses (metastatic, equivocal, or negative for metastasis) of the original report and slide review for both cytology and histopathology were not significantly correlated with survival in this population of patients. Overall, agreement between cytology and histopathology was poor even with a single clinical or anatomic pathologist performing slide review. Consensus between routine cytology and histopathology for staging of lymph nodes in patients with melanocytic neoplasms is poor and does not correlate with survival.

Effect of vascular seal configuration using the LigaSure on arterial challenge pressure, time for seal creation, and histologic features.

OBJECTIVE: To determine the effectiveness of a vascular sealing technology on canine carotid arteries using various seal configurations to achieve maximal vessel security. STUDY DESIGN: Ex-vivo study. ANIMALS: Dogs (n = 20). METHODS: Carotid arteries (n = 40) were removed from the mid-cervical region of recently euthanatized dogs. Harvested vessels were closed with 2 circumferential ligatures (Group 1) or a vascular sealing device using 1 of 4 seal configurations of 1 or 2 seals combined with 1 or 2 machine activations/seal. The artery was instrumented to measure intraluminal pressure to evaluate the security of each seal during saline infusion. Maximum intraluminal pressure was recorded for each group, and time for application of each sealing protocol was compared using 1-way ANOVA and Tukey's test for multiple comparisons. Histologic features of the sealing protocols were evaluated. RESULTS: Arterial closures for each group were effective in preventing leakage up to 300 mmHg. There was no significant difference in maximum intraluminal pressure between any group. A significant difference (P ≤ .001) was observed for time to seal creation between the groups using 1 and 2 seals. Histologic evaluation showed no differences between the different sealing protocols. CONCLUSION: Vessel sealing using a single seal created with a single activation cycle was adequate for sealing canine carotid arteries. Histologic examination did not demonstrate any disadvantages to multiple seals or multiple cycle activations.

Effect of enteric biopsy closure orientation on enteric circumference and volume of saline needed for leak testing.

This study describes the effect of enteric biopsy closure orientation on circumference and volume of saline needed for leak testing. There were significant differences in circumference measurements at baseline, central circumference of longitudinally closed sites, and volume of saline for leak testing.

Effet de l'orientation de la fermeture de la biopsie entérique sur la circonférence entérique et le volume de solution saline requis pour l'essai d'étanchéité. Cette étude décrit l'effet de l'orientation de la fermeture de la biopsie entérique sur la circonférence et le volume de solution saline requis pour l'essai d'étanchéité. Il y avait des différences importantes dans les mesures de la circonférence pour les données de référence, la circonférence centrale des sites fermés longitudinalement et le volume de solution saline pour l'essai d'étanchéité.(Traduit par Isabelle Vallières).

Evaluation of zoledronate for the treatment of canine stage III osteosarcoma: A phase II study.

BACKGROUND: Greater than 90% of dogs with appendicular osteosarcoma will develop pulmonary metastasis despite the standard of care. Available treatments have limited efficacy for stage III disease. Zoledronate, a bisphosphonate, induces apoptosis of canine osteosarcoma cells and appears to modulate the tumour microenvironment. OBJECTIVES: This prospective, single institutional phase IIa trial investigated the use of single agent zoledronate in dogs with pulmonary metastases from osteosarcoma. METHODS: Zoledronate was administered once monthly, and thoracic radiographs were used to assess response. RESULTS: Eleven dogs were enrolled. Stable disease was achieved in two of eight dogs available for response assessment. The median progression-free survival was 28 days (range: 4-93 days). The median stage III-specific survival time was 92 days. Adverse events were reported in four dogs; two dogs developed grade III or higher toxicities. Notable adverse events included conjunctivitis, fever, hypocalcaemia, and hypophosphatemia. CONCLUSIONS: Zoledronate appears to have limited efficacy as a single agent for stage III osteosarcoma and may be associated with unexpected toxicity in this population. This clinical trial was registered on the AVMA Animal Health Studies Database (AAHSD004396).

Influence of stapler type on in vitro leakage pressures and location of functional end-to-end stapled anastomoses.

The objective of this study was to compare maximal leakage pressures and locations of 2 functional end-to-end stapled anastomosis (FEESA) constructs. Grossly normal jejunum was harvested from 4 large breed dogs. Thirty-two 8-cm segments of bowel were used to construct 16 FEESA. Construct type was divided into 2 groups: traditional FEESA (tFEESA) and modified FEESA (mFEESA). Leakage pressures and locations were recorded and compared for the 2 groups. There was no difference in the leakage pressures of the tFEESA and the mFEESA. However, 1 tFEESA did leak at subphysiologic intestinal peristaltic pressures. Although no difference in maximal leakage pressure was detected between the 2 constructs, mFEESA is an attractive alternative to tFEESA, as it requires less equipment and none of the mFEESA constructs leaked at subphysiologic pressures.

L'objectif de cette étude était de comparer les pressions de fuite maximales et les emplacements de deux assemblages fonctionnels d'anastomose agrafée bout à bout (FEESA). Du jéjunum macroscopiquement normal a été prélevé sur quatre chiens de grande race. Trente-deux segments de 8 cm d'intestin ont été utilisés pour produire 16 FEESA. Le type d'assemblage a été divisé en deux groupes : FEESA traditionnel (tFEESA) et FEESA modifié (mFEESA). Les pressions et emplacements des fuites ont été enregistrés et comparés pour les deux groupes. Il n'y avait aucune différence dans les pressions de fuite du tFEESA et du mFEESA. Cependant, un tFEESA a fui à des pressions péristaltiques intestinales sous-physiologiques. Bien qu'aucune différence de pression de fuite maximale n'ait été détectée entre les deux types d'assemblage, mFEESA est une alternative attrayante à tFEESA, car elle nécessite moins d'équipement et aucun des assemblages mFEESA n'a fui à des pressions sous-physiologiques.(Traduit par Docteur Serge Messier).

Pathology in Practice.

In collaboration with the American College of Veterinary Pathologists.

Dogs ≥ five years of age at the time of congenital extrahepatic portosystemic shunt diagnosis have better long-term outcomes with surgical attenuation than with medical management alone.

OBJECTIVE: To determine the outcome in dogs diagnosed with congenital extrahepatic portosystemic shunts (EHPSS) at ≥ 5 years of age treated with medical management only (M) or with surgical attenuation (S). The hypothesis was that dogs undergoing surgical attenuation would have a longer survival time than dogs undergoing medical management only. ANIMALS: 351 dogs definitively diagnosed with EHPSS at ≥ 5 years of age. PROCEDURES: Medical records from 2009 to 2019 at 16 veterinary teaching hospitals were evaluated. Data collected included signalment, clinical signs at diagnosis, clinicopathologic data, surgical and medical treatments, shunt morphology, clinical signs and medical treatments at 6 to 12 months after diagnosis, and survival time. RESULTS: 351 dogs (M, 119 [33.9%]; S, 232 [66.1%]) were included in the study. Survival time was longer with surgery than medical management (hazard ratio, 4.2; M, 3.4 years; S, 10.9 years). Continued clinical signs at 6 to 12 months after diagnosis were more common with medical management (M, 40% [33/88]; S, 14% [21/155]). Continued medical treatments at 6 to 12 months after diagnosis were more common in the medical management group (M, 78% [69/88]; S, 34% [53/155]). Perioperative mortality rate was 7.3%. CLINICAL RELEVANCE: Dogs diagnosed at ≥ 5 years of age with EHPSS have significantly better survival times and fewer clinical signs with surgical attenuation, compared with medical management. Older dogs have similar surgical mortality rates to dogs of all ages after surgical EHPSS attenuation.