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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Summary:

Twenty horses with 30 lesions were studied to evaluate the effects of intratumoral chemotherapy with cisplatin in sesame oil on equine sarcoids (n = 19), squamous cell carcinomas (n = 7), and squamous cell papillomas (n = 4). Treatment consisted of 4 sessions of intratumoral cisplatin chemotherapy at 2-week intervals. A controlled-release formulation of cisplatin in sesame oil was used to limit drug egress from the injection site. Mean dosage per session was 0.97 (±0.17, sem) mg of cisplatin/cm3 of tumor tissue treated for tumor volumes ranging from 10 to 20 cm3. Dosage tended to be slightly higher for smaller tumors and slightly lower for larger tumors. Tumor regression was observed in all horses. Complete response was observed in 18 of the sarcoids, 5 of the squamous cell carcinomas, and 4 of the squamous cell papillomas. The mean relapse-free interval was 21.6 and 14 months in horses with sarcoid and carcinoma/papilloma, respectively. The 1-year relapse-free rates were 87 and 65% for equine sarcoid and carcinoma/papilloma, respectively. In horses with relapse, 70% had tumor recurrence outside the treated field. Cisplatin-related local toxicosis was minimal. Intratumoral cisplatin chemotherapy was found to be a practical and effective treatment of sarcoid and squamous cell carcinoma/papilloma in horses.

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in Journal of the American Veterinary Medical Association

SUMMARY

In this preliminary investigation, various hematologic variables potentially influential in determining the degree of blood viscosity were evaluated in 10 Thoroughbred horses subjected to competitive acute running exercise. Following completion of sprints over a distance of 1.25 miles, mean percent (± sd) increases in pcv (38.3 ± 12.9%), rbc (47.8 ± 15.3%), and rouleaux index (232.7 ± 176.8%) were recognized. Simultaneous increases in total plasma protein (28.3 ± 5.31%), serum albumin (26.7 ± 6.80%), α1-globulin (60.0 ± 49.0%), α2-globulin (25.5 ± 27.9%), β1-globulin (46.7 ± 21.1%), (32-globulin (35.0 ± 50.6%), γ1- and 2-globulins (38.7 ± 29.6%), and plasma fibrinogen (12.5 ± 10.4%) concentrations increased simultaneously. Horses also had consistent decreases in albumin:globulin ratio (- 10.0 ± 7.43%). Alterations in these hematologic values after acute running exercise in Thoroughbred horses accompanied increases in serum (69.3 ± 39.7%), plasma (39.7 ± 11.9%), and blood (134.7 ± 55.3%) viscosity.

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in American Journal of Veterinary Research

Objective—

To characterize history, clinical signs, and pathologic findings in horses with histologically confirmed acute hemorrhagic pulmonary infarction and necrotizing pneumonia.

Design—

Retrospective study.

Animals—

21 horses.

Results—

19 of the 21 horses were Thoroughbred racehorses in training. Eighteen horses had had strenuous exercise immediately prior to onset of illness. Fifteen horses had a serosanguineous nasal discharge during hospitalization. Seventeen horses had radiographic evidence of pulmonary consolidation and pleural effusion. Nine of 14 horses had ultrasonographic evidence of large pulmonary parenchymal defects consistent with consolidation. Pleurocentesis yielded a suppurative, serosanguineous effusion in the 14 horses in which it was performed. Bacteria were isolated from all transtracheal aspirates (14) and from 6 of 12 pleural fluid samples. Actinobacillus suis-like organisms and Streptococcus equi subsp zooepidemicus were most commonly isolated. Nineteen horses were hospitalized and treated, Mean duration of treatment was 5 days, and most horses were euthanatized because of secondary complications, continued costs of medical treatment, or poor prognosis for future performance. Pathologic lesions included well-demarcated regions of hemorrhagic pulmonary infarction with necrosis and a serosanguineous pleural effusion. Thrombosis of pulmonary vessels was found in 11 horses.

Clinical Implications—

An acute or peracute onset of severe respiratory distress, with serosanguineous nasal discharge, ultrasonographic and radiographic evidence of severe pulmonary consolidation, and serosanguineous suppurative pleural effusion, is strongly suggestive of pulmonary infarction in horses. Horses with pulmonary infarction responded poorly to conventional treatment for pleuropneumonia and had a poor prognosis for recovery. (J Am Vet Med Assoc 1997;210:1774–1778)

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in Journal of the American Veterinary Medical Association

Summary

To determine whether body direction in a trailer affects the degree to which a horse is excited (and presumably stressed) during transport, heart rates were measured in 8 Thoroughbred geldings transported over a 32-km route of county roads while tethered facing forward or backward in a 4-horse stock trailer. Heart rates also were measured on the horses while they were tethered facing forward or backward in the same trailer while it was parked. Heart rates decreased during the first 10 minutes for both groups, and remained stable after the first 15 minutes. Heart rates were not significantly different between horses facing forward or backward during transport or while parked. Heart rates were significantly (P < 0.05) higher for horses during transport, compared with those of horses in a parked trailer whether facing forward or backward.

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in American Journal of Veterinary Research

Abstract

Objective—To evaluate the use of multifrequency bioelectrical impedance analysis (MF-BIA) for estimating total body water (TBW), extracellular fluid volume (ECFV), and intracellular fluid volume (ICFV) in horses.

Animals—9 healthy mares.

Procedure—TBW and ECFV were measured by use of deuterium oxide and sodium bromide dilution techniques, respectively. Intracellular fluid volume was calculated as the difference between TBW and ECFV. Concurrently, MF-BIA recordings were obtained by use of 4 anatomic electrode positions and 3 measurements of length. Models for MF-BIA data were created for all combinations of length and anatomic electrode position. Models were evaluated to determine the position-length configuration that provided the most consistent estimates of TBW, ECFV, and ICFV, compared with values determined by use of the dilution techniques.

Results—Positioning electrodes over the ipsilateral carpus and tarsus and use of height at the tuber sacrale for length provided the closest estimate between values for TBW, ECFV, and ICFV predicted by use of MF-BIA and measured values obtained by dilutional techniques. This model had the narrowest 95% limits of agreement.

Conclusions and Clinical Relevance—MF-BIA techniques have been used to predict changes in TBW, ECFV, and ICFV in healthy and diseased humans. Results reported in this study provide an equine-specific model to serve as the basis for further evaluation of MF-BIA in horses with altered fluid states. The MF-BIA techniques have a number of potential applications for use in horses, including evaluation of exercise physiology, pharmacologic studies, and critical-care management. ( Am J Vet Res 2004;65:320–326)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To apply the principle of sodium dilution to calculate the changes in the extracellular fluid (ECF) volume (ECFV) and intracellular fluid volume (ICFV) that occur during dehydration and rehydration in horses.

Animals—8 healthy horses of various breeds.

Procedures—Horses were dehydrated over 4 hours by withholding water and administering furosemide. Saline (0.9% NaCl) solution was administered IV during the next 2 hours (20 mL/kg/h; total 40 mL/kg). Horses were monitored for an additional hour following IV fluid administration. Initial ECFV was determined by use of multifrequency bioelectrical impedance analysis, and serum sodium concentration was used to calculate total ECF sodium content. Sodium and fluid volume losses were monitored and calculated throughout the study and used to estimate changes in ECFV and ICFV during fluid balance alterations.

Results—Changes during dehydration and rehydration primarily occurred in the ECFV. The sodium dilution principle estimated an overexpansion of the ECFV beyond the volume of fluid administered, indicating a small contraction of the ICFV in response to fluid administration. Serum and urinary electrolyte changes were recorded and were consistent with those of previous reports.

Conclusions and Clinical Relevance—The sodium dilution principle provided a simple method that can be used to estimate the changes in ECFV and ICFV that occur during fluid administration. Results suggested an overexpansion of the ECFV in response to IV saline solution administration. The sodium dilution principle requires further validation in healthy and clinically ill horses, which could provide clinical applications similar to those in other species.

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in American Journal of Veterinary Research

Summary:

Four Quarter Horses (1 stallion, 3 mares) with hyperkalemic periodic paralysis were mated to unaffected horses to determine the genetic basis of the disease. The affected stallion was bred to 11 unaffected mares (4 Quarter Horses, 1 Arabian, 2 Standardbreds, and 4 Thoroughbreds). The 3 affected mares were bred to an unaffected Quarter Horse stallion.

Of the 15 offspring obtained from these matings, 9 were affected with hyperkalemic periodic paralysis, and 6 were unaffected, consistent with an autosomal dominant mode of inheritance. Diagnosis was established by results of oral administration of potassium chloride and demonstration of characteristic clinical signs accompanied by hyperkalemia. Oral administration of potassium chloride resulted in marked increases in plasma potassium concentrations in affected and unaffected foals, although hyperkalemia was associated with clinical signs of hyperkalemic periodic paralysis in the affected foals. Evaluation of blood samples from affected and unaffected offspring revealed no linkage with erythrocyte and serum markers at 24 loci.

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in Journal of the American Veterinary Medical Association