Nobuyuki Kanemaki

Dogs and Humans Share a Common Susceptibility Gene SRBD1 for Glaucoma Risk

Glaucoma is a degenerative optic neuropathy that is associated with elevated intraocular pressure. Primary open angle glaucoma is the most common type of glaucoma in canines, and its highest incidence among dog breeds has been reported in Shiba-Inus, followed by Shih-Tzus. These breeds are known to have an abnormal iridocorneal angle and dysplastic prectinate ligament. However, the hereditary and genetic backgrounds of these dogs have not yet been clarified. In this study, we investigated the association between polymorphisms of the glaucoma candidate genes, SRBD1, ELOVL5, and ADAMTS10, and glaucoma in Shiba-Inus and Shih-Tzus. We analyzed 11 polymorphisms in these three genes using direct DNA sequencing. Three SRBD1 SNPs, rs8655283, rs22018514 and rs22018513 were significantly associated with glaucoma in Shiba-Inus, while rs22018513, a synonymous SNP in exon 4, showed the strongest association (P = 0.00039, OR = 3.03). Conditional analysis revealed that rs22018513 could account for most of the association of these SNPs with glaucoma in Shiba-Inus. In Shih-Tzus, only rs9172407 in the SRBD1 intron 1 was significantly associated with glaucoma (P = 0.0014, OR = 5.25). There were no significant associations between the ELOVL5 or ADAMTS10 polymorphisms and glaucoma in Shiba-Inus and Shih-Tzus. The results showed that SRBD1 polymorphisms play an important role in glaucoma pathology in both Shiba-Inus and Shih-Tzus. SRBD1 polymorphisms have also been associated with normal- and high-tension glaucomas in humans. Therefore, SRBD1 may be a common susceptibility gene for glaucoma in humans and dogs. We anticipate that the nucleotide sequencing data from this study can be used in genetic testing to determine for the first time, the genetic status and susceptibility of glaucoma in dogs, with high precision. Moreover, canine glaucoma resulting from SRBD1 polymorphisms could be a useful animal model to study human glaucoma.

Aquaporin 1 expression in tissues of canines possessing inherited high

We investigated the expression of aquaporin 1 (AQP1) in tissues from canines with an inherited anomaly that causes their erythrocytes to have high K+. Northern blot analysis revealed abundant AQP1 expression in lung and kidney, though little expression was found in spleen. Using anti-C-terminus for dog AQP1, abundant expression was shown in kidney, trachea, and eye, but little expression was shown in pancreas and cerebrum, indicating that AQP1 expression in canine tissues is similar to that noted in other mammals.

K^+

Cutaneous sterile pyogranuloma/granuloma syndrome (SPGS) is a locally restricted multinodular dermatitis. Affected dogs are typically healthy, but a few show systemic signs. Herein, a case of a dog presenting with generalized ulcerative dermatitis with systemic signs of mild anemia and an increased C-reactive protein level is described. Cutaneous SPGS was diagnosed by histopathology, negative staining causative organisms, and polymerase chain reaction for Mycobacterium spp. Successful treatment was achieved by immunosuppressive drugs, including prednisolone and azathioprine, administered for at least 20 mo. Recurrences of skin lesions were observed when prednisolone and/or azathioprine were discontinued. Long-term management with immunosuppressive agents may be required if the affected dog exhibits severe symptoms of cutaneous SPGS.

erythrocytes

Cationic amino acid transport activity in a canine lens epithelial cells (LEC) line was investigated. The transporter activity of arginine was 0.424 ± 0.047 nmol/mg protein min, while the presence of N-ethylmaleimide, an inhibitor of the canine cationic amino acid transporter (CAT), reduced transport activity by 30%. A full-length cDNA sequence of canine CAT1 was 2558 bp long and was predicted to encode the 629 amino acid polypeptides. The deduced amino acid sequence of canine CAT1 showed similarities of 92.1% and 88.6% to those of the human and mouse, respectively. Western blot analysis detected a band at 70 kDa in a membrane protein sample of LEC. RT-PCR analysis confirmed that CAT1 was ubiquitously detected in all tissues examined.

A Case of Cutaneous Sterile Pyogranuloma/Granuloma Syndrome in a Maltese

Unilateral (left eye) optic nerve hypoplasia was detected in a six-month-old male Beagle dog. Vision testing indicated that the left eye had poor vision and testing the pupillary light reflex showed the left eye to have an absence of the afferent pathway of the reflex but it had a normal efferent pathway. Ophthalmoscopy revealed a small-sized optic disc, winding retinal artery and dilated retinal vasculature in the left globe. Electroretinography showed no abnormal findings even in the left globe. Histopathologically, the left optic nerve was markedly hypoplastic and was composed of sparse neural elements and a moderate amount of connective and glial tissues. In the retina of the left globe, the nerve fibre layer and the ganglion cell layer were reduced in thickness, although a small number of ganglion cells were still present. There were no abnormal findings detected in the right globe and the right optic nerve. The brain appeared normal macroscopically.

Analysis of Cationic Amino Acid Transport Activity in Canine Lens Epithelial Cells

OBJECTIVE To introduce a simple method for fundus photography of dogs and cats using a smartphone and indirect ophthalmoscopy lenses. METHODS Fundus photographs of dogs and cats with transparent ocular media were obtained with 15D, 20D, 28D, and 40D indirect lenses and an iPhone-6, in a dark room and after pharmacologic pupil dilation. The photographs were recorded as still images using a video application and a video-to-still image application. Two types of neutral density (ND) filters were used as required for reduction of the torch illumination power of the iPhone. RESULTS The images obtained in this study were upside-down as a result of the optics used. A 180-degree rotation was used to show their natural anatomical orientation. The image field of view varied with the diopter strength of the indirect lens used. The 40-diopter lens offered the widest field. CONCLUSION Still images obtained with a smartphone, and indirect lenses may be useful for client communication and teaching in small animal ophthalmology.

Unilateral optical nerve hypoplasia in a Beagle dog

Purpose Many studies have investigated the relationship of paired box 6 (PAX6) gene polymorphisms with the risk of high myopia, but the results across studies remain inconsistent and ambiguous. In the present work, we investigated whether PAX6 polymorphisms are associated with high myopia in a Japanese population. Methods A total of 1,585 Japanese patients with high myopia (spherical equivalent [SE] <−9.00 diopters [D]) and 1,011 Japanese healthy controls (SE≥−1.00 D) were recruited. To compare genotype frequencies between cases and controls, we genotyped five single nucleotide polymorphisms in the PAX6 gene that are reportedly associated with high/extreme myopia: rs662702, rs3026393, rs644242, rs3026390, and rs667773. Results For rs662702, rs644242, and rs667773, odds ratios (ORs) for their risk alleles tended to increase with the progression of SE and axial length in the additive and recessive models. Of these, rs644242 had the highest OR (2.56) in patients with SE<−15 D in both eyes in the recessive model. On the other hand, for rs3026393 and rs3026390, the ORs for their risk alleles tended to increase according to the progression of SE and axial length in the dominant model. Of the two, rs3026393 had the highest OR (2.32) in patients with SE<−15 D in both eyes in the dominant model. However, no significant associations were identified in this study. Conclusion We found that these PAX6 single nucleotide polymorphisms were associated with an increased risk of extreme myopia. Although the results, which are in agreement with some previous studies, did not reach statistical significance, PAX6 single nucleotide polymorphisms may be important risk factors for the development of extreme myopia. Further genetic studies with larger sample sizes and taking into account the degree of myopia are needed to clarify the contribution of PAX6 variants in myopia development.

Fundus photography with a smartphone in indirect ophthalmoscopy in dogs and cats.

ABSTRACT The cystine transport activity of a lens epithelial cell line originated from a canine mature cataract was investigated. The distinct cystine transport activity was observed, which was inhibited to 28% by extracellular 1 mM glutamate. The cDNA sequences of canine cysteine/glutamate exchanger (xCT) and 4F2hc were determined. The predicted amino acid sequences were 527 and 533 amino acid polypeptides, respectively. The amino acid sequences of canine xCT and 4F2hc showed high similarities (>80%) to those of humans. The expression of xCT in lens epithelial cell line was confirmed by western blot analysis. RT-PCR analysis revealed high level expression only in the brain, and it was below the detectable level in other tissues.

Study of association of PAX6 polymorphisms with susceptibility to high myopia in a Japanese population.

We describe for the first time the diagnosis of Schizophyllum commune infection in a captive cheetah. Eosinophilic plasmacytic conjunctivitis was detected histopathologically in a biopsy specimen. Both a second surgical specimen and drainage fluid from a gingival mass and fistula contained fungal hyphae in giant cells with granulomatous inflammation. Allergic S. commune mycosis was suspected at this point. A monokaryotic isolate was characterized morphologically, and then identified genetically. Treatment with itraconazole and pimaricin was effective.

Canine Amino Acid Transport System Xc–: cDNA Sequence,Distribution and Cystine Transport Activity in Lens Epithelial Cells

Objective To detect antibodies for lens βH-crystallins in the serum from the American Cocker Spaniel (ACS) presenting with and without cataracts and with and without uveitis. Animal Studied Seventy-three American Cocker Spaniels and six normal Beagles. Procedures Sera were collected from 73 ACSs, including those with normal lenses and those with cataracts, or uveitis. Fractionated, normal Beagle lens βH-crystallins were separated by one- or two-dimensional electrophoresis. The separated lens βH-crystallins were used on immunoblots as sentinel substrates against which the ACS sera were tested for the presence of antibodies against βH-crystallins. Results Sera from approximately two-thirds of study animals contained antibodies to some βH-crystallin polypeptides, but reactivity varied among patients. Contrary to some hypotheses, serum antibodies to groups of βH-crystallins did not relate to the stages of cataract. However, detailed analysis by two-dimensional immunoblotting and mass spectrometry showed that three spots originating from βA1-crystallin were detected only in sera from cataract patients. Conclusion Serum antibodies to βA1-crystallin may be associated with the development of cataract.