Kazumi Nibe

Plasma anti-Müllerian hormone as a biomarker for bovine granulosa-theca cell tumors: Comparison with immunoreactive inhibin and ovarian steroid concentrations

Granulosa-theca cell tumors (GTCTs) are the most frequently reported ovarian tumors in cattle. Clinically, GTCTs could be confused with other ovarian abnormalities; therefore, the only definitive diagnosis for such tumors is histopathology of a biopsy from the affected ovary. However, this is an invasive technique and unsuitable for farm conditions. As a result, the key aim of this study was to evaluate the diagnostic value of anti-Müllerian hormone (AMH), a glycoprotein hormone that is synthesized exclusively by ovarian granulosa cells, as a sensitive noninvasive biomarker for diagnosing GTCTs in cattle. To achieve this aim, we conducted two experiments. In experiment 1, four clinically healthy Japanese Black cows had blood samples taken daily over one estrous cycle to characterize their AMH profiles throughout the estrous cycle. Additionally, single blood samples were collected from 21 cyclic cows to clarify the physiological range of AMH. In experiment 2, cows with histologically confirmed GTCT (GTCT group, n = 9) and cows affected with cystic ovarian disease (COD group, n = 8) had one blood sample taken before extraction of the tumorous ovary or therapeutic treatment for the COD. Blood samples (n = 105) from cyclic cows (n = 25) in experiment 1 were assigned as a physiologically cyclic group (PC group). Plasma AMH, immunoreactive inhibin (ir-INH), estradiol-17β (E2), testosterone (T), and progesterone (P4) concentrations were assayed in all samples. In experiment 1, the mean plasma AMH concentration was 0.09 ± 0.003 ng/mL and did not show substantial fluctuation throughout the estrous cycle. In experiment 2, plasma AMH, ir-INH, and E2 concentrations were significantly elevated in the GTCT group in comparison with the PC group; among these parameters, only the AMH concentrations were significantly higher in the GTCT group than in the COD group. The area under the receiver operating characteristic curve of AMH for diagnosis of GTCT was 0.99 and was significantly higher than that of ir-INH (P < 0.001) and E2 (P < 0.01). Moreover, the AMH at a cutoff point of ≥0.36 ng/mL had the highest diagnostic accuracy (99.2%), sensitivity (100%), and specificity (99.1%) compared with the other tested parameters. In conclusion, plasma AMH concentration is probably a more reliable and sensitive biomarker for bovine GTCTs than the concentrations of ir-INH or ovarian steroids.

Immunohistochemical Features of Dystrophic Axons in Papillon Dogs with Neuroaxonal Dystrophy

The immunohistochemical features of dystrophic axons in brain tissues of Papillon dogs with neuroaxonal dystrophy (NAD) were examined in comparison with 1 dog with cerebellar cortical abiotrophy (CCA) and a dog without neurologic signs. Histologically, many dystrophic axons were observed throughout the central nervous system of all dogs with NAD. These axonal changes were absent in the dog with CCA and in the control dog. Severe Purkinje cell loss was found in the dog with CCA, whereas the lesions were milder in all dogs with NAD. Immunohistochemically, the many dystrophic axons were positive for neurofilaments, tau, α/β-synuclein, HSP70, ubiquitin, synaptophysin, syntaxin-1, and synaptosomal-associated protein-25 (SNAP-25). A few dystrophic axons were positive for α-synuclein. In addition, these dystrophic axons, especially in the nucleus gracilis, cuneatus, olivaris, and spinal tract of the trigeminal nerve, were intensely immunopositive for the 3 calcium-binding proteins calretinin, calbindin, and parvalbumin. The accumulation of synapse-associated proteins in the dystrophic axons may indicate dysfunction of the synapse at the presynaptic portion. The accumulation of α-synuclein in the dystrophic axon and region-specific appearance of calcium-binding protein-positive spheroids are considered as unique features in NAD of Papillon dogs, providing the key to elucidate the pathogenesis.

Detection of antibodies against Fusobacterium necrophorum and Porphyromonas levii‐like species in dairy cattle with papillomatous digital dermatitis

Bovine digital epidermitis involves different pathologies, including PDD, interdigital dermatitis, and foot rot. Bacteriological and molecular biological studies suggest that these are multimicrobial infections. During our study on the isolation of treponemes from biopsies of PDD, colonies producing black pigment were isolated frequently from the primary cultures, suggesting that Porphyromonas species were present. Moreover, 16S rRNA genes of Fusobacterium necrophorum and Porphyromonas levii‐like species were detected in the lesions. We therefore determined whether an immunological response could be elicited by a P. levii‐like organism isolated from a PDD lesion, as well as two subspecies of F. necrophorum in the sera from cows with and without PDD. A total of 151 serum samples were collected from 85 cows with PDD lesions and 33 cows without lesions on 12 PDD‐positive farms and from 33 cows on two PDD‐free farms. ELISA data showed that IgG antibody levels against antigens of P. levii‐like species and F. necrophorum subsp. necrophorum were significantly higher in cows on PDD‐positive farms than in cows on PDD‐free farms, regardless of the presence of PDD lesions in the cows on the PDD‐positive farms. However, F. necrophorum subsp. funduliforme was present at low levels in both groups. The ELISA results were confirmed by western blot analysis. Furthermore, antigens of these bacteria were detected in PDD‐biopsy sections examined by immunohistochemical staining. F. necrophorum subsp. necrophorum and P. levii‐like species may be involved in the pathogenesis of PDD.

GM2 Gangliosidosis Variant 0 (Sandhoff‐Like Disease) in a Family of Toy Poodles

BACKGROUND GM2 gangliosidosis variant 0 (human Sandhoff disease) is a lysosomal storage disorder caused by deficiencies of acid β-hexosaminidase (Hex) A and Hex B because of an abnormality of the β-subunit, a common component in these enzyme molecules, which is coded by the HEXB gene. OBJECTIVE To describe the clinical, pathological, biochemical, and magnetic resonance imaging (MRI) findings of Sandhoff-like disease identified in a family of Toy Poodles. ANIMALS Three red-haired Toy Poodles demonstrated clinical signs including motor disorders and tremor starting between 9 and 12 months of age. The animals finally died of neurological deterioration between 18 and 23 months of age. There were some lymphocytes with abnormal cytoplasmic vacuoles detected. METHODS Observational case study. RESULTS The common MRI finding was diffuse T2-hyperintensity of the subcortical white matter in the cerebrum. Bilateral T2-hyperintensity and T1-hypointensity in the nucleus caudatus, and atrophic findings of the cerebrum and cerebellum, were observed in a dog in the late stage. Histopathologically, swollen neurons with pale to eosinophilic granular materials in the cytoplasm were observed throughout the central nervous system. Biochemically, GM2 ganglioside had accumulated in the brain, and Hex A and Hex B were deficient in the brain and liver. Pedigree analysis demonstrated that the 3 affected dogs were from the same family line. CONCLUSIONS AND CLINICAL IMPORTANCE The Sandhoff-like disease observed in this family of Toy Poodles is the 2nd occurrence of the canine form of this disease and the 1st report of its identification in a family of dogs.

Growth and genotypes of Echinococcus granulosus found in cattle imported from Australia and fattened in Japan

At the abattoir on study in Miyazaki, Japan, 9537 imported cattle from Australia in average were slaughtered annually in the last 5 years (2006 to 2010) and hydatid cysts were constantly detected in about 1.8% of the cattle. In order to assess the risk of Echinococcus granulosus delivered to Japan by imported cattle, 250 cysts found in 103 cattle at the abattoir were examined for their biological characteristics and genotypes. The cattle slaughtered were imported from Australia at an age of 10-12 months old and fattened for 17-18 months in Japan. The cysts showed their size ranging from 4 to 108 mm and were mainly found in the lung. Mature protoscoleces were detected in the three largest cysts, all were of the G1 genotype. Most of the other cysts contained clear cyst fluid and had thin laminated layer with no protoscoleces. The finding implies a potential risk of E. granulosus being established in Japan, thus strict and proper meat inspection and consequent offal condemnation are requisite at abattoirs that deal with imported cattle. Genotyping based on partial fragments of mitochondrial cox1, rrnS and nad1 genes were performed on the 66 cysts, showing that most of the cysts were G1 genotype (common sheep strain). However, two and four cysts were considered as G2 (Tasmanian sheep strain) and G3 (buffalo strain) genotypes, respectively. Since it has been widely recognized that G1 is the only genotype distributing in mainland Australia and that G2 genotype has been eradicated from Tasmania, the finding of those genotypes from Australian cattle indicated that certain genotypes other than G1 genotype are distributing in mainland Australia.

A case of canine apocrine sweat gland adenoma, clear cell variant

A cutaneous mass at the base of the retroauricular region of a 4-year-old, female Golden Retriever was examined pathologically. Histologically, the mass formed multiple nodules consisting of a proliferation of large clear cells with abundant cytoplasm. Mitotic figures among the neoplastic cells were very sparse. The large clear cells were intensely positive for cytokeratins (AE1/AE4, cytokeratin 8 and 18) and moderately positive for lysozyme and contained periodic acid-Schiff-positive granules in the cytoplasm. In addition, small flat cells lined the islands of neoplastic large clear cells, and these were strongly positive for alpha-smooth muscle actin and vimentin, and some were positive for cytokeratin (AE1/AE4), suggesting they were myoepithelial cells. No local recurrence or metastasis has been recognized during the 18 months since surgical excision. On the basis of these findings, the present tumor was diagnosed as apocrine sweat gland adenoma, clear cell variant. There have been few previous reports of canine apocrine adenomas showing a clear cell morphology.

Clinical and Pathologic Features of Neuronal Ceroid-Lipofuscinosis in a Ferret (Mustela putorius furo)

Clinical and pathologic features of neuronal ceroid-lipofuscinosis in a 4-month-old ferret are reported. Clinical signs including neurological symptoms appeared at 3 months of age and progressed rapidly. By magnetic resonance imaging, severe cerebral atrophy was recognized. Histopathologically, there was severe neuronal loss and diffuse astrogliosis with macrophage accumulations; lesions were found predominantly in the cerebral cortex. Intracytoplasmic pigments were observed in surviving neurons and macrophages throughout the brain. The pigments were intensely positive for periodic acid–Schiff, Luxol fast blue, and Sudan black B and exhibited a green autofluorescence. Electron microscopic examination revealed the accumulation of electron-dense granular material within lysosomes of neurons and macrophages. Immunohistochemically, a large number of saposin-positive granules accumulated in the neuronal cells, astrocytes, and macrophages of the lesions, but significant immunoreactivity for subunit c of mitochondrial adenosine triphosphate synthase was not observed. Based on these findings, the animal was diagnosed as affected by neuronal ceroid-lipofuscinosis.

Adaptation of wild-type measles virus to cotton rat lung cells: E89K mutation in matrix protein contributes to its fitness.

Wild-type measles virus (wtMeV) adapted well to cotton rat lung (CRL) cells after serial passages. In order to evaluate the contributions of the individual genes of wtMeV for adaptation, whole genome sequences of the adapted and original viruses were determined and analyzed. The results showed that there were two mutations in the whole genome of the adapted virus. One mutation was located at the 265th nucleotide in the open reading frame (ORF) of the M gene, resulting in the substitution of the 89th amino acid from E (glutamate) to K (lysine). The other was a silent mutation located at the 4182nd nucleotide in the ORF of the L gene. It was demonstrated that the E89K mutation in the M protein is responsible for the adaptation of wtMeV MV99Y in CRL cells. Cotton rats were infected with adapted virus and the original strain via intranasal inoculation. Virus titer results showed that adapted strain replicated better than the original strain in cotton rat lungs. It is suggested that the E89K mutation also contributes to the enhancement of wtMeV replication in a cotton rat model infected intranasally. The results revealed that the E89K mutation in the M protein plays a key role in wtMeV adaptation in cotton rat and CRL cells.

Identification of the PLA2G6 c.1579G>A Missense Mutation in Papillon Dog Neuroaxonal Dystrophy Using Whole Exome Sequencing Analysis

Whole exome sequencing (WES) has become a common tool for identifying genetic causes of human inherited disorders, and it has also recently been applied to canine genome research. We conducted WES analysis of neuroaxonal dystrophy (NAD), a neurodegenerative disease that sporadically occurs worldwide in Papillon dogs. The disease is considered an autosomal recessive monogenic disease, which is histopathologically characterized by severe axonal swelling, known as “spheroids,” throughout the nervous system. By sequencing all eleven DNA samples from one NAD-affected Papillon dog and her parents, two unrelated NAD-affected Papillon dogs, and six unaffected control Papillon dogs, we identified 10 candidate mutations. Among them, three candidates were determined to be “deleterious” by in silico pathogenesis evaluation. By subsequent massive screening by TaqMan genotyping analysis, only the PLA2G6 c.1579G>A mutation had an association with the presence or absence of the disease, suggesting that it may be a causal mutation of canine NAD. As a human homologue of this gene is a causative gene for infantile neuroaxonal dystrophy, this canine phenotype may serve as a good animal model for human disease. The results of this study also indicate that WES analysis is a powerful tool for exploring canine hereditary diseases, especially in rare monogenic hereditary diseases.

The Origin and Role of Autophagy in the Formation of Cytoplasmic Granules in Canine Lingual Granular Cell Tumors

Granular cell tumors (GCTs) are histologically characterized by polygonal neoplastic cells with abundant eosinophilic cytoplasmic granules. In humans, these cells are considered to be derived from Schwann cells, and the cytoplasmic granules are assumed to be autophagosomes or autophagolysosomes. However, the origin and nature of the cytoplasmic granules in canine GCTs have not been well characterized. The present study examined 9 canine lingual GCTs using immunohistochemistry, transmission electron microscopy (TEM), and cell culture and xenotransplantation experiments. In some cases, the tumor cells expressed S100, CD133, and desmin. The cytoplasmic granules were positive for LC3, p62, NBR1, and ubiquitin. TEM revealed autophagosome-like structures in the cytoplasm of the granule-containing cells. The cultured GCT cells were round to spindle shaped and expressed S100, nestin, Melan-A, CD133, LC3, p62, NBR1, and ubiquitin, suggesting that they were of neural crest origin, redifferentiated into melanocytes, and exhibited upregulated autophagy. The xenotransplanted tumors consisted of spindle to polygonal cells. Only a few cells contained cytoplasmic granules, and some had melanin pigments in their cytoplasm. The xenotransplanted cells expressed S100, nestin, Melan-A, and CD133. P62 and ubiquitin were detected, regardless of the presence or absence of cytoplasmic granules, while LC3 and NBR1 were detected only in the neoplastic cells containing cytoplasmic granules. These findings suggest that some xenotransplanted cells redifferentiated into melanocytes and that autophagy was upregulated in the cytoplasmic granule-containing cells. In conclusion, canine lingual GCTs originate from the neural crest and develop cytoplasmic granules via autophagy. In addition, the microenvironment of GCT cells affects their morphology.