Friesian horses have a perceived high rate of congenital or hereditary diseases, including megaesophagus, that may lead to choke and death. A retrospective study was performed to determine the prevalence and pathologic characteristics of esophageal disease in 852 horses, including 17 Friesians, that had been necropsied over a 6-year period at the Diagnostic Center for Population and Animal Health. Forty-two horses had grossly described esophageal lesions (25 muscular hypertrophy, 7 hemorrhage, 6 megaesophagus, 4 erosion/ulceration, 3 obstruction, 2 tears, 2 secondary neoplasms, 2 lymphoid patches, 1 thin wall, 1 esophagitis). Some of these lesions occurred concurrently in the same horse. Ten of these horses died or were euthanatized because of severe esophageal disease (6 megaesophagus causing tears in 2 horses, 3 esophageal obstruction with food bolus, and 1 esophagitis). All 6 horses with megaesophagus were Friesians. No cause for megaesophagus was noted in the necropsy reports; however, 5 of these 6 Friesians had marked caudal esophageal muscular hypertrophy (wall thickness: 1.9 ± 0.3 cm). Microscopic review of the esophagus of these Friesians confirmed smooth muscle hypertrophy, with no obvious fibrosis, degeneration, or loss of myenteric plexi. Unlike the Friesians, the 4 non-Friesian horses with severe esophageal disease had esophageal obstruction with an intraluminal food bolus or severe esophagitis. None had caudal esophageal muscular hypertrophy. It is concluded that in comparison to other horse breeds, Friesians have a higher prevalence of severe esophageal disease, specifically megaesophagus, that is commonly associated with marked caudal muscular hypertrophy.

ABSTRACT. To clarify the immunohistochemical characteristics of canine ovarian cysts, 109 canine ovarian cysts (57 cysts of subsurface epithelial structures: SES, 26 graafian follicle cysts, 12 cystic rete ovarii and 14 cysts difficult to classify morphologically) were examined regarding their lining cells immunohistochemically using antibodies against placental alkaline phosphatase (PLAP), S100, inhibin α, desmin and AE1/AE3. Both cysts of SES and cystic rete ovarii had a positive immunoreaction to desmin and AE1/AE3, whereas all cysts all but graafian follicle cysts were negative for inhibin α. PLAP-positive immunoreaction was observed only in cysts of SES. Graafian follicle cysts had a positive immunoreaction to inhibin α, but were negative for PLAP, desmin and AE1/AE3. Fourteen cysts were difficult to classify morphologically because these cysts had single-squamous lining cells and lacked other morphological characteristics. However, these unclassified cysts were immunohistochemically divided into two groups, including positive and negative cysts, by the reactivity of PLAP. The PLAP-positive cysts were considered large cysts of SES. These results suggest that PLAP was a useful marker for classification of cysts of SES, although cysts originating from SES are not always positive for this antigen. KEY WORDS: canine, immunohistochemistry, ovarian cyst.

The histologic diversity of epidermal laminae from hooves of Thoroughbreds was attributable to the combined morphology of PEL and SEL. Detection of hyperplastic changes in the laminar interface does not justify a diagnosis of laminitis because such changes can develop independent of clinical disease. The classification system used here should aid investigators in making a more accurate histologic evaluation of laminae.

ABSTRACT. In this study, the expression and distribution of monocarboxyolate transporter 1 (MCT1) along the intestines (duodenum, jejunum, ileum, cecum, colon and rectum) of dogs were investigated at both the mRNA and protein levels. The expression of MCT1 protein and its distribution were confirmed by Western blotting and immunohistochemical staining using the antibody for MCT1. We identified mRNA coding for MCT1 and a 43-kDa band of MCT1 protein in all regions from the duodenum to the rectum. Immunoreactive staining for MCT1 was also observed in epithelial cells throughout the intestines. MCT1 immunoreactivity was greater in the large intestine than in the small intestine. MCT1 protein was predominantly expressed on the basolateral membranes along intestinal epithelial cells, suggesting that MCT1 may play an important role in lactate efflux and transport of short-chain fatty acids (SCFAs) to the bloodstream across the basolateral membranes of the dog intestine. KEY WORDS: canine, intestine, monocarboxylate transporter 1.

A male 25-month-old Dalmatian dog attended our veterinary hospital because of anorexia and high circulating liver enzyme activities. Abdominal computed tomography showed a slightly small liver with rounded edges, and laparoscopic examination showed that the liver was yellowish.Histopathological examination revealed multifocal necrosis of hepatocytes and severe chronic hepatitis. Rhodanine staining showed severe copper accumulation in hepatocytes and a quantitative analysis of the copper content of the liver showed substantial accumulation (10.3 mg/g dry mass), suggesting a diagnosis of copper-associated hepatitis. Previously reported canine mutation in the COMMD1, the gene responsible for the copper-associated hepatitis in the Bedlington terrier, was not identified. To our knowledge, this is the first report of copper-associated hepatitis in a Dalmatian in Japan.