RADIATION THERAPY COMMUNICATION: EQUINE HEMANGIOMA

A 13-month-old Standardbred Colt had a recurrent hemangioma at the level of the coronary band. Multiple excisions had led to a nonhealing skin and hoof defect. Using 14 MV electrons, a total dose of 36 Gy was administered, given as six fractions of 6 Gy twice a week. Wound healing by second intention was achieved over the next 4 months and the colt began race training 6 months after the end of therapy. Twenty months later the colt is sound and there is no evidence of tumor recurrence.     

Cardiovascular and pulmonary effects of hetastarch plus hypertonic saline solutions during experimental endotoxemia in anesthetized horses

BACKGROUND: Small volume resuscitation has been advocated as a beneficial therapy for endotoxemia in horses but this therapy has not been investigated in a prospective manner. The objective of this study was to determine the cardiopulmonary effects of small-volume resuscitation using hypertonic saline solution (HSS) plus Hetastarch (HES) during experimental endotoxemia in anesthetized horses. HYPOTHESIS: Treatment of horses with induced endotoxemia using HES-HSS does not alter the response of various cardiopulmonary indices when compared to treatment with either small- or large-volume isotonic crystalloid solutions. ANIMALS: Eighteen healthy horses were randomly assigned to 1 of 3 groups. Anesthesia was maintained with halothane. Endotoxemia was induced by administering 50 microg/kg of Escherichia coli endotoxin IV. The horses were treated over 30 minutes with 15 mL/kg of balanced polyionic crystalloid solution (control), 60 mL/kg of balanced polyionic crystalloid solution (ISO), or 5 mL/kg of HSS followed by 10 mL/kg of HES (HSS-HES). METHODS: Prospective randomized trial. RESULTS: Cardiac output (CO) after endotoxin infusion increased significantly (P < .05) from baseline in all groups, whereas mean central venous pressure increased significantly (P < .05) in the ISO group only. Mean pulmonary artery pressure increased from baseline (P < .05) in horses treated with isotonic fluids and HSS-HES. There was no effect of treatment with HSS-HES on CO, systemic vascular resistance (SVR), mean arterial pressure, blood lactate concentrations, or arterial oxygenation. CONCLUSIONS AND CLINICAL IMPORTANCE: The use of HSS-HES failed to ameliorate the deleterious hemodynamic responses associated with endotoxemia in horses. The clinical value of this treatment in horses with endotoxemia remains unconfirmed.     

TOTAL SKIN ELECTRON THERAPY TECHNIQUE FOR THE CANINE PATIENT

Cutaneous epitheliotropic T‐cell lymphoma in canine patients is a radiation sensitive tumor but total skin electron therapy is used only rarely. Our purpose was to evaluate dose distribution from a total skin electron therapy technique using 6 MeV electron beams. The treatment was comprised of 12 fields, with the dog in lateral recumbency in a stride position at an extended distance from the source. Uniformity, flatness and symmetry were determined for each beam. The composite percent depth dose profile for all beams was measured in solid water phantoms and skin dose was determined on a canine cadaver using thermoluminescent dosimeters. The resulting d_max of the composite beams was 1 mm and dose variation over the skin was 6.8%, with the extremities having the most uneven dose distribution. Dimensions of the fields were adequate to obtain an effective treatment profile for the entire thickness of canine epidermis and the technique was feasible for clinical application. Individual tailoring of the protocol to deal with hot and cold spots may be necessary and set up will likely involve a significant time commitment for the therapy team.     

Heart Rate Variability in Horses Engaged in Equine-Assisted Activities

Although there has been a recent surge in using horses to treat mental and emotional human health issues, the consequences of horse-assisted interventions on the stress response of horses have not been well documented. Assessment of the autonomic nervous system and its regulation of cardiovascular function has been used as an indicator of acute and chronic stress in human beings and horses. Heart rate variability (HRV) is a noninvasive measurement that has been used to assess autonomic nervous system regulation of cardiovascular function. There is evidence to suggest that several factors including the genotype, behavior, environment, temperament, and nutritional status of the horse play a key role in the large inter-individual variations in basal HRV. The present study determined whether 24-hour HRV recordings in horses currently working in equine-assisted therapy (EAT) differ from those previously shown in Thoroughbred horses. Findings from the present study found that in contrast to previous studies in Thoroughbred horses, diurnal and nocturnal low frequency and high frequency powers were not significantly different in horses that are currently engaged in EAT. Future studies are needed to determine the short- and long-term consequences of horses participating in EAT programs. Findings from this study will provide the basis for the development of a physiological/behavioral assessment criteria to determine the consequences of EAT on the well-being of horses as well as to help EAT Centers to improve the beneficial effects of EAT in human beings.     

Analysis of KIT expression and KIT exon 11 mutations in canine oral malignant melanomas

KIT, a transmembrane receptor tyrosine kinase, is one of the specific targets for anti-cancer therapy. In humans, its expression and mutations have been identified in malignant melanomas and therapies using molecular-targeted agents have been promising in these tumours. As human malignant melanoma, canine malignant melanoma is a fatal disease with metastases and the poor response has been observed with all standard protocols. In our study, KIT expression and exon 11 mutations in dogs with histologically confirmed malignant oral melanomas were evaluated. Although 20 of 39 cases were positive for KIT protein, there was no significant difference between KIT expression and overall survival. Moreover, polymerase chain reaction amplification and sequencing of KIT exon 11 in 17 samples did not detect any mutations and proved disappointing. For several reasons, however, KIT expression and mutations of various exons including exon 11 should be investigated in more cases.