Surgical treatment of feline inductive odontogenic tumor by marginal resection in a cat.

A 1-year-old mixed-breed cat was referred for an approximately 2-cm mass centered on the upper right canine tooth. Computed tomography (CT) revealed the lesion extended to the nasal cavity and orbit, causing thinning and expansion of the adjacent cortical bone. Excisional biopsy confirmed the diagnosis of a feline inductive odontogenic tumor. Based on the findings of CT imaging, the primary alveolar bone lesion was removed with the tumor, while the adjacent bones, which had been expanded and thinned, were preserved by marginal resection including the surrounding periosteum-like membrane. No local recurrence was observed for seven years. To validate the therapeutic outcome of this case, further research in diagnostic imaging and pathology will be crucial.

Characterization of equine hyalocytes: their immunohistochemical properties, morphologies and distribution.

In horse, the characterizations of hyalocytes under the steady state are still unclear. Therefore, we investigated characterizations of hyalocytes in normal equine eyes by their immunohistochemical phenotype, histomorphology and distribution. Thirty-one eyes from 18 horses, divided into 4 groups (G) by age, were used: early (G1) and late gestation (G2) fetuses, 1- to 3-year-old (G3) and 8- to 24-year-old (G4) horses. Equine hyalocytes were histologically classified into 4 types, and they immunohistochemically expressed MHC II and CD163. Hyalocytes were detected on and/or around ciliary processes and pars plana in G2, G3 and G4, but were not located on retina and optic papilla. A significant increase in distribution was found between G2 and both G3 and G4, and the largest distribution was found at ciliary processes in these groups. Equine hyalocytes were characterized as residential ocular macrophage and MHC II antigen-bearing cell, accompanied by a pleomorphic appearance and located in the contiguous ciliary body. Our data provided characterizations of hyalocytes in normal equine eyes and may well contribute to improving the understanding of pathogenesis of equine ocular disease.

Histological and immunohistochemical evaluation of stroma variations and their correlation with the Ki-67 index and expressions of glucose transporter 1 and monocarboxylate transporter 1 in canine thyroid C-cell carcinomas.

Canine thyroid C-cell carcinomas (CTCCs) are malignant tumors derived from calcitonin-producing C-cells of the thyroid gland. This study aimed to investigate the histological diversity of CTCCs from the viewpoint of stroma variations and to investigate their components by histological and immunohistochemical analyses including semiquantitative analysis of the density of microvessels (MVs) and α-SMA-positive cell count. Moreover, we examined whether the variations correlated with the Ki-67 index and expressions of glucose transporter 1 (GLUT-1) and monocarboxylate transporter 1 (MCT-1). Three stroma types (reticular, R, nest, N, and trabecular, T) were observed in CTCCs, and 21 cases were divided into 3 variations based on their combinations: mixed R and N (R/N) (n=7), simple N (n=7) and mixed T and N (T/N) (n=7). Immunohistochemically, stroma types depended on morphological features of α-SMA/fibronectin/laminin/collagen type IV-positive stroma cells. The density of MVs in R/N tended to be highest, and the density of those in N was significantly higher than the density of those in T/N (P=0.028). The α-SMA-positive cell count for N tended to be the lowest among the 3 variations. The Ki-67 index for R/N was significantly higher than those of the other variations (vs. N, P=0.007; vs. T/N, P=0.03), and that for T/N tended to be higher than that for N. Although there were no significant differences, GLUT-1 and MCT-1 expressions tended to be low in N. We concluded that stroma variations reflect tumor cell proliferation and expressions of GLUT-1 and MCT-1 in CTCCs.

Distribution of CD163-positive cell and MHC class II-positive cell in the normal equine uveal tract.

Antigen-presenting cells (APCs) in the uveal tract participate in ocular immunity including immune homeostasis and the pathogenesis of uveitis. In horses, although uveitis is the most common ocular disorder, little is known about ocular immunity, such as the distribution of APCs. In this study, we investigated the distribution of CD163-positive and MHC II-positive cells in the normal equine uveal tract using an immunofluorescence technique. Eleven eyes from 10 Thoroughbred horses aged 1 to 24 years old were used. Indirect immunofluorescence was performed using the primary antibodies CD163, MHC class II (MHC II) and CD20. To demonstrate the site of their greatest distribution, positive cells were manually counted in 3 different parts of the uveal tract (ciliary body, iris and choroid), and their average number was assessed by statistical analysis. The distribution of pleomorphic CD163- and MHC II-expressed cells was detected throughout the equine uveal tract, but no CD20-expressed cells were detected. The statistical analysis demonstrated the distribution of CD163- and MHC II-positive cells focusing on the ciliary body. These results demonstrated that the ciliary body is the largest site of their distribution in the normal equine uveal tract, and the ciliary body is considered to play important roles in uveal and/or ocular immune homeostasis. The data provided in this study will help further understanding of equine ocular immunity in the normal state and might be beneficial for understanding of mechanisms of ocular disorders, such as equine uveitis.

Identification and preservation of the parathyroid gland during total thyroidectomy in dogs with bilateral thyroid carcinoma: a report of six cases.

Simultaneous removal of bilateral thyroid tumors was performed while preserving the parathyroid gland in six dogs. At least one external parathyroid gland was identified in all dogs. In five cases, the external parathyroid gland and its blood supply were preserved intact. In one dog, the vessels supplying the external parathyroid gland had been invaded by the tumor, and the gland was thus removed and reimplanted into the sternohyoid muscle. That dog required postoperative treatment with oral calcium gluconate and vitamin D3. Local tumor recurrence was not observed in any of the cases. The mean survival time was 920 days. We found that the external parathyroid gland could be identified and preserved in most dogs undergoing total thyroidectomy.

Sustained heterozygosity across a self-incompatibility locus in an inbred ascidian.

Because self-incompatibility loci are maintained heterozygous and recombination within self-incompatibility loci would be disadvantageous, self-incompatibility loci are thought to contribute to structural and functional differentiation of chromosomes. Although the hermaphrodite chordate, Ciona intestinalis, has two self-incompatibility genes, this incompatibility system is incomplete and self-fertilization occurs under laboratory conditions. Here, we established an inbred strain of C. intestinalis by repeated self-fertilization. Decoding genome sequences of sibling animals of this strain identified a 2.4-Mbheterozygous region on chromosome 7. A self-incompatibility gene, Themis-B, was encoded within this region. This observation implied that this self-incompatibility locus and the linkage disequilibrium of its flanking region contribute to the formation of the 2.4-Mb heterozygous region, probably through recombination suppression. We showed that different individuals in natural populations had different numbers and different combinations of Themis-B variants, and that the rate of self-fertilization varied among these animals. Our result explains why self-fertilization occurs under laboratory conditions. It also supports the concept that the Themis-B locus is preferentially retained heterozygous in the inbred line and contributes to the formation of the 2.4-Mb heterozygous region. High structural variations might suppress recombination, and this long heterozygous region might represent a preliminary stage of structural differentiation of chromosomes.

Intestinal undifferentiated carcinoma in a red-crowned crane (Grus japonensis).

A 33-year-old red-crowned crane (Grus japonensis) had a diffuse intestinal thickening from the duodenum to colon. Microscopically, neoplastic cells were arranged in sheets and occasionally nests or cords without gland or squamous differentiation. Metastatic tumor cells were found in the lungs, heart, kidneys and adrenal glands. Immunohistochemically, the neoplastic cells were strongly positive for pan-cytokeratin and cytokeratin 8 and 18 and only partly positive for E-cadherin antibodies. Immunostaining for CD3 was positive in normal lymphocytes, and NSE was also positive in normal nerve fibers. But, the neoplastic cells were not immunoreactive to CD3 and NSE. Based on the histological features and the epithelial characteristics in the immunohistochemical stain, the present case was diagnosed as undifferentiated carcinoma originating from the intestine. Interestingly, the neoplastic cells showed a unique growth pattern; they never invaded the submucosa or muscularis throughout the intestine, whereas they spread lymphogenously or hematogenously to other organs.

Predicting metastatic potential of gastrointestinal stromal tumors in dog by ultrasonography.

Gastrointestinal stromal tumor (GIST), a mesenchymal neoplasm affecting the gastrointestinal tract, shows a variety of clinical behaviors from inactive benign to aggressive malignant in dogs. In this study, the feasibility of using clinically significant ultrasonographic features to predict the metastatic potential of canine GIST was investigated through comparison with actual metastatic incidence and findings of malignancy obtained by postoperative pathological examination. Ultrasonographic features, including large tumor size, irregular margin and heterogeneous internal echogenicity with large hypoechoic areas, related closely with the presence of metastasis as well as a high-risk ranking by the human classification system according to pathological findings. Based on these ultrasonographic features, the potential of metastasis in canine GIST could be preoperatively predicted.

Contrast agent Gd-EOB-DTPA (EOB·Primovist®) for low-field magnetic resonance imaging of canine focal liver lesions.

Contrast-enhanced magnetic resonance (MR) imaging with a new liver-specific contrast agent gadolinium-ethoxybenzyl-diethylenetriamine penta-acetic acid (Gd-EOB-DTPA; EOB·Primovist®) was studied in 14 normal beagles and 9 dogs with focal liver lesions. Gd-EOB-DTPA accumulates in normally functioning hepatocytes 20 min after injection. As with Gd-DTPA, it is also possible to perform a dynamic multiphasic examination of the liver with Gd-EOB-DTPA, including an arterial phase and a portal venous phase. First, a reliable protocol was developed and the appropriate timings for the dynamic study and the parenchymal phase in normal dogs using Gd-EOB-DTPA were determined. Second, the patterns of these images were evaluated in patient dogs with hepatic masses. The optimal time of arterial imaging was from 15 s after injection, and the optimal time for portal venous imaging was from 40 s after injection. Meanwhile, the optimal time to observe changes during the hepatobiliary phase was from 20 min after injection. In patient dogs, 11 lesions were diagnosed as malignant tumors; all were hypointense to the surrounding normal liver parenchyma during the hepatobiliary phase. Even with a low-field MR imaging unit, the sequences afforded images adequate to visualize the liver parenchyma and to detect tumors within an appropriate scan time. Contrast-enhanced MR imaging with Gd-EOB-DTPA provides good demarcation on low-field MR imaging for diagnosing canine focal liver lesions.

Pathological classification of canine mammary tumor based on quantifying mRNA levels of hormonal receptors, SATB1, and Snail in tissue and fine needle biopsy samples.

Cytological diagnosis is not generally conclusive enough to identify histopathological malignancy in canine mammary tumors (CMTs). To establish cytological examination using fine needle biopsy (FNB) samples, gene expressions of hormonal receptors, human epidermal growth factor receptor 2 (HER2), and transcription regulators (Special AT-rich binding protein 1: SATB1 and Snail) were investigated in both tissue and FNB samples of CMTs. In tissue samples of malignant CMTs, especially invasive ones, low expressions of hormonal receptors and high expressions of SATB1 and Snail were detected. On discriminant analysis of tissue samples, 73.2% of CMTs were correctly classified according to histopathological examinations. In FNB samples of malignant CMTs, low expressions of hormonal receptors were detected. On discriminant analysis of FNB samples, 74.2% of CMTs were correctly classified according to histopathological examination. In conclusion, FNB gene expressions had a utility for diagnosis of CMTs malignancy in some degree. By researching more sensitive genes for malignant CMTs, the gene examination of FNB samples from CMTs will become a useful diagnostic tool that can be performed easily without anesthesia and could predict tumor malignancy and invasion prior to surgical removal.

Cutaneous lymphoplasmacytic lymphoma with systemic metastasis in a cat.

A lymphoplasmacytic lymphoma was diagnosed in a 12- year-old domestic cat that had a primary cutaneous mass involving the stomach, liver, kidneys, heart, abdominal wall, diaphragm, bone marrow and several lymph nodes. Histopathologically, the most characteristic feature of this tumor was the heterogeneity of cell components, such as small lymphocytes, well-differentiated plasma cells and plasmacytoid transformed lymphocytes. Amyloid was deposited in the skin, stomach, and several lymph nodes. Immunohistochemically, neoplastic small lymphocytes were positive for CD20, and well-differentiated plasma cells and plasmacytoid transformed lymphocytes were positive for λ-Ig light chains and MUM1/IRF-4. These results emphasize the importance of lymphoplasmacytic lymphoma as a differential diagnosis of extramedullary cutaneous plasmacytoma in cats.

Mycobacterium ulcerans infection in an Indian flap-shelled turtle (Lissemys punctata punctata).

We report an atypical mycobacterial infection in an Indian flap-shelled turtle, Lissemys punctata punctata, that died in an aquarium in Japan. At necropsy, the turtle showed multiple white nodules on the capsular surface and parenchyma of various organs such as the liver, spleen, intestine, and lung. Histologically, granulomatous inflammation surrounding a central zone of necrosis was observed. Sections stained by the Ziehl-Neelsen method revealed numerous acid-fast bacilli in the cytoplasm of macrophages and in the central area of necrosis. The organisms were identified as a mycobacterial species by PCR and nucleotide sequence analysis and revealed 98-100% homology to M. ulcerans. This is, to our knowledge, the first report of mycobacteriosis due to M. ulcerans in a turtle.

Systemic candidiasis and mesenteric mast cell tumor with multiple metastases in a dog.

A 5-year-old female miniature dachshund presenting with persistent vomiting and diarrhea had two concurrent rare pathological conditions: systemic candidiasis and mesenteric mast cell tumor with multiorgan metastases. Neoplastic mast cells formed mass in the mesentery of the cecal-colonic region and were also found in the liver, spleen, kidneys, lungs, adrenal grands, ovaries, bone marrow and other tissues. The cells had intracytoplasmic granules with metachromasia and were immunohistochemically positive for c-kit and histamine. Granulomatous lesions with fungal organisms were present in the heart, lungs, kidneys, pancreas, subserosal and surrounding adipose tissue of the duodenum, thyroid glands and mesenteric mass, and phagocytosed organisms were detected in the liver and bone marrow. Bacteriologically and immunohistochemically, the fungi were consistent with Candida albicans.

Histologic evaluation of the diversity of epidermal laminae in hooves of horses without clinical signs of laminitis.

OBJECTIVE: To evaluate the histologic diversity of epidermal laminae in hooves from horses without clinical signs of laminitis. SAMPLE POPULATION: Formalin-fixed samples of stratum internum obtained from the mid region of the dorsal aspect of the hoof wall from the forelimbs of 35Thoroughbred cadavers (including foals [n = 9], yearlings [5], 2 year olds [6], racing horses [5], and mares [10]). PROCEDURES: Paraffin-embedded laminar tissues were stained with H&E for the evaluation of architectural variety of primary epidermal laminae (PEL) and secondary epidermal laminae (SEL). For detection of cytokeratin (CK) expression in epidermal laminae, immunohisto-chemical staining was performed by use of anti-CK14 and anti-CK8.12 antibodies. RESULTS: The morphology of the PEL, SEL, and tips of PEL was classified into 3, 5, and 3 patterns, respectively. Differences in the predominant type of SEL depended on their location with respect to the laminar interface. In SEL attached to the sides of PEL, the basal cells were immunoreactive to CK14 and CK8.12, which was interpreted as a normal pattern. In some SEL at the tips of PEL, the suprabasal cells expressed CK14, CK8.12, or both, which constituted a hyperplastic pattern. CONCLUSIONS AND CLINICAL RELEVANCE: 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.

Tubulopapillary carcinoma with spindle cell metaplasia of the mammary gland in a cat.

Sarcomatous proliferation of spindle cells was present in the mammary gland and many metastatic sites in a 10-year-old female domestic cat with tubulopapillary carcinoma in the mammary gland. Transition from neoplastic tubular structures to spindle cells in the primary site and fascicular proliferation of the spindle cells with or without coexistance of tubulopapillary carcinoma in the primary and metastatic sites were observed. Most of spindle cells were positive for cytokeratin CAM5.2 as well as the normal luminal epithelium but not the myoepithelium. From these results, this case was diagnosed as tubulopapillary carcinoma with spindle cell metaplasia and it was clarified that neoplastic luminal epithelial cells can transform to sarcomatous appearence.

Aldosterone-, corticosterone- and cortisol-secreting adrenocortical carcinoma in a dog: case report.

A 12-year-old, intact female beagle exhibited symptoms of polyuria-polydipsia and hyperorexia for two months. Blood tests showed elevated asparate aminotransferase, alanine aminotransferase, alkaline phosphatase and creatine kinase levels, as well as marked hypokalemia. The results of adrenocorticotropic hormone stimulation test showed elevated cortisol, aldosterone and corticosterone concentrations. Abdominal ultrasonography confirmed a mass in the left adrenal gland. Masses were also seen in the liver and caudal vena cava. Diagnosis was a tumor of the adrenal cortex with metastases. Trilostane administration was initiated. The dog initially showed improved demeanor as a result of regulating hormone secretion. However, after 88 days, the dog weakened rapidly, before dying on the 117th day. Pathological findings confirmed a diagnosis of adrenocortical carcinoma.

Immunohistochemical evaluation of canine ovarian cysts.

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 alpha, 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 alpha. PLAP-positive immunoreaction was observed only in cysts of SES. Graafian follicle cysts had a positive immunoreaction to inhibin alpha, 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.

Immunohistochemical evaluation of canine ovarian tumors.

Canine ovarian tumors (epithelial tumor, sex-cord stromal tumor, germ cell tumor) classifying into 9 histological types were examined immunohistochemically using placental alkaline phosphatase (PLAP), cytokeratin7 (CK7), desmin, S100, AE1/AE3, inhibin alpha, vimentin, and alfa feto-protein (AFP). The papillary and tubular types observed in epithelial tumors were immunoreactive for desmin and AE1/AE3. The papillary type was also immunoreactive for PLAP and CK7. The solid type, nest type, cord type, palisade type, cystic type and spindle type, which were observed in sex-cord stromal tumors, showed a positive immunoreaction for S100 but little or no positive immunoreaction for inhibin alpha with an exception of positive result in the palisade type. Most of the sex-cord stromal tumors were AE1/AE3-positive except for the palisade type. In the cobblestone type observed in germ cell tumors, only vimentin and AFP were positive. The present study elucidated the detailed histological and immunohistochemical characteristics of canine ovarian tumors.

Expression of monocarboxylate transporter 1 (MCT1) in the dog intestine.

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.

Culture of Ciona intestinalis in closed systems.

Improvements in closed-system culturing methods for marine invertebrates are important prerequisites for the generalized use of transgenic lines. We discuss here the effects of several closed-system conditions on the growth and survival of the solitary ascidian, Ciona intestinalis. In Shimoda, close to the sea, a small-tank system was used to ensure that tanks and systems were reasonably equipped, water exchange was rapid, and animals separated to minimize the risk of infection. In Gif-sur-Yvette, an inland site, we tried to determine the optimal conditions to limit handling operations, and to save artificial seawater by avoiding water pollution. A mixture of at least two types of live algae was better than any single-organism diet. With these maintenance protocols, we were able to obtain several generations of Ciona intestinalis, including several transgenic lines. Because these systems make it easier to rear Ciona intestinalis in laboratories, they increase the potentialities of this model organism for research.