Novel extracellular matrix wound dressing shows increased epithelialization of full-thickness skin wounds in dogs.

OBJECTIVE: To compare the differences in the healing of surgically created full-thickness wounds in dogs treated with a novel extracellular matrix (ECM) dressing as compared with a standard wound management protocol and to investigate the effect of antibiotics in these 2 populations. ANIMALS: 15 purpose-bred Beagles, 8 female spayed and 7 males neutered, operated on, and monitored between March 14, 2022, and April 18, 2022. METHODS: Four 2 X 2-cm full-thickness skin wounds were created on the trunks of each dog. The right-sided wounds were treated with the novel ECM wound dressing, and the left-sided wounds served as the controls. Wound planimetry and qualitative wound scores were obtained at 12 time points. Wound biopsies for histopathologic assessment of wound repair and wound inflammation were obtained at 6 time points. RESULTS: Wounds treated with ECM had higher percent epithelization at days 7, 9, 12, and 18 postoperatively (P < .001) and better histologic repair scores (P = .024) than wounds treated by the standard protocol. Subjective wound assessment scores of wounds treated with ECM did not differ from those treated by the standard protocol at any time point. CLINICAL RELEVANCE: Wounds treated with the novel ECM dressing epithelialized more rapidly than wounds treated by a standard protocol.

Characterizing the Ablative Effects of Histotripsy for Osteosarcoma: In Vivo Study in Dogs.

Osteosarcoma (OS) is a malignant bone tumor treated by limb amputation or limb salvage surgeries and chemotherapy. Histotripsy is a non-thermal, non-invasive focused ultrasound therapy using controlled acoustic cavitation to mechanically disintegrate tissue. Recent ex vivo and in vivo pilot studies have demonstrated the ability of histotripsy for ablating OS but were limited in scope. This study expands on these initial findings to more fully characterize the effects of histotripsy for bone tumors, particularly in tumors with different compositions. A prototype 500 kHz histotripsy system was used to treat ten dogs with suspected OS at an intermediate treatment dose of 1000 pulses per location. One day after histotripsy, treated tumors were resected via limb amputation, and radiologic and histopathologic analyses were conducted to determine the effects of histotripsy for each patient. The results of this study demonstrated that histotripsy ablation is safe and feasible in canine patients with spontaneous OS, while offering new insights into the characteristics of the achieved ablation zone. More extensive tissue destruction was observed after histotripsy compared to that in previous reports, and radiographic changes in tumor size and contrast uptake following histotripsy were reported for the first time. Overall, this study significantly expands our understanding of histotripsy bone tumor ablation and informs future studies for this application.

Histotripsy Ablation of Spontaneously Occurring Canine Bone Tumors In Vivo.

OBJECTIVE: Osteosarcoma (OS) is a devastating primary bone tumor in dogs and humans with limited non-surgical treatment options. As the first completely non-invasive and non-thermal ablation technique, histotripsy has the potential to significantly improve the standard of care for patients with primary bone tumors. INTRODUCTION: Standard of care treatment for primary appendicular OS involves surgical resection via either limb amputation or limb-salvage surgery for suitable candidates. Biological similarities between canine and human OS make the dog an informative comparative oncology research model to advance treatment options for primary OS. Evaluating histotripsy for ablating spontaneous canine primary OS will build a foundation upon which histotripsy can be translated clinically into a standard of care therapy for canine and human OS. METHODS: Five dogs with suspected spontaneous OS were treated with a 500 kHz histotripsy system guided by real-time ultrasound image guidance. Spherical ablation volumes within each tumor (1.25-3 cm in diameter) were treated with single cycle histotripsy pulses applied at a pulse repetition frequency of 500 Hz and a dose of 500 pulses/point. RESULTS: Tumor ablation was successfully identified grossly and histologically within the targeted treatment regions of all subjects. Histotripsy treatments were well-tolerated amongst all patients with no significant clinical adverse effects. Conclusion & Significance: Histotripsy safely and effectively ablated the targeted treatment volumes in all subjects, demonstrating its potential to serve as a non-invasive treatment modality for primary bone tumors.

Focused ultrasound tumour ablation in small animal oncology.

The cancer incidence rates for humans and animals remain high, and efforts to improve cancer treatment are crucial. Cancer treatment for solid tumours includes both treatment of the primary tumour and of metastasis. Surgery is commonly employed to resect primary and metastatic tumours, but is invasive, and is not always the optimal treatment modality. Prevention and treatment of metastatic disease often utilizes a multimodal approach, but metastasis remains a major cause of death for both human and veterinary cancer patients. Focused ultrasound (FUS) tumour ablation techniques represent a novel non-invasive approach to treating cancer. FUS ablation is precise, thus sparing adjacent critical structures while ablating the tumour. FUS ablation can occur in a thermal or non-thermal fashion. Thermal FUS ablation, also known as high intensity focused ultrasound (HIFU) ablation, destroys tumour cells via heat, whereas non-thermal FUS, known as histotripsy, ablates tumour cells via mechanical disintegration of tissue. Not only can HIFU and histotripsy ablate tumours, they also demonstrate potential to upregulate the host immune system towards an anti-tumour response. The aim of this report is provide a description of HIFU and histotripsy tumour ablation, with a focus on the basic principles of their ablation mechanisms and their clinical applicability in the field of veterinary oncology.

Evaluation of gastric emptying time, gastrointestinal transit time, sedation score, and nausea score associated with intravenous constant rate infusion of lidocaine hydrochloride in clinically normal dogs.

OBJECTIVE To quantify nausea and sedation scores, gastric emptying time, and gastrointestinal transit time after IV administration of a lidocaine hydrochloride bolus followed by a constant rate infusion (CRI) in clinically normal dogs. ANIMALS 6 Beagles. PROCEDURES In a crossover study, dogs were fed thirty 1.5-mm barium-impregnated spheres (BIPS) and received a saline (0.9% NaCl) solution bolus (0.05 mL/kg) IV (time 0) followed by a CRI at 10 mL/h, a lidocaine bolus (1 mg/kg) IV followed by a CRI at 25 µg/kg/min, or a lidocaine bolus (1 mg/kg) IV followed by a CRI at 50 µg/kg/min; CRIs were for 12 hours. Nausea and sedation scores were assessed and abdominal radiographs obtained immediately after feeding of BIPS and every hour for 12 hours and again 16 hours after CRI start. Percentage of BIPSs in the small and large intestines, gastric emptying time, and gastrointestinal transit time were assessed. RESULTS Gastric emptying time did not differ significantly among treatments. Significantly more BIPS were in the large intestine 4 to 7 hours after treatment start for the 50-µg/kg/min treatment than for the other 2 treatments. Six hours after treatment start, significantly more BIPS were in the large intestine for the 25-µg/kg/min treatment than for the saline solution treatment. Higher sedation and nausea scores were associated with the 50-µg/kg/min CRI. CONCLUSIONS AND CLINICAL RELEVANCE In clinically normal dogs, lidocaine CRI did not significantly affect gastric emptying. However, gastrointestinal transit time was mildly decreased and sedation and nausea scores increased in dogs administered a lidocaine CRI at clinically used doses.