Publications by authors named "Yasuhiko Okamura"

Background: Intracranial histiocytic sarcoma (HS) is uncommon in dogs, and no standard treatment has yet been defined for this disease. Herein, we describe a case of intracranial HS that responded favorably to nimustine treatment.

Case Description: A 9-year-old, castrated Welsh Corgi Pembroke presented with a 2-month history of quadriplegia.

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Article Synopsis
  • * The dog, which showed no clinical symptoms, underwent surgery to remove a pulmonary mass that exhibited unusual contrast patterns on a CT scan, raising concerns during the operation.
  • * Histopathological analysis and urinary tests confirmed the diagnosis of primary paraganglioma, highlighting the need to consider catecholamine-producing tumors in asymptomatic lung tumors with specific imaging characteristics.
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Canine pulmonary adenocarcinoma (PAC) resembles human lung tumors in never-smokers, but it is rarer than human pulmonary adenocarcinoma. Therefore, research on canine PAC is challenging. In the present study, we successfully established various novel canine PAC cell lines from a single lesion in a dog, including two parent cell lines and fourteen cloned cell lines, and characterized their cellular properties in vitro.

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Cancers utilize a variety of molecules to escape host immune responses. Better understanding the immune environment surrounding cancer may facilitate application of innovative cancer immunotherapies, such as immune checkpoint inhibitors, to dogs as well as humans. In this study, we screened the expression of 20 immune regulatory molecules in diverse canine tumors (n = 59).

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A three-year-old male Pug presented with a three-year history of urolithiasis and repeated urethral obstruction. Biochemical analysis, ultrasonography, and retrograde urethrocystography revealed probable portosystemic shunt and incomplete urethral obstruction due to uric acid ammonium calculi. Enhanced computed tomography (CT) revealed portosystemic shunt and proliferation of the osseous tissue of the os penis, which was surgically removed.

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A 9-year-old male intact domestic cat weighing 4.6 kg was referred for tachypnea. A large mass was visible in computed tomography (CT) scans of the thoracic cavity.

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An 11-year-old male Miniature Dachshund was referred for acute neurological deficits in the pelvic limbs. T2-weighted magnetic resonance imaging revealed that the spinal cord at the L1-2 intervertebral disc space was heterogeneously hyperintense in the sagittal plane and was mildly compressed from the ventral side by a small hypointense mass in the transverse plane. However, the lesion showed mass enhancement and severe spinal cord compression on post-contrast T1-weighted imaging.

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Objectives: The aim of this study was to investigate the antiemetic, behavioural and physiological effects of oral maropitant treatment before the administration of brimonidine ophthalmic solution in healthy cats.

Methods: Five cats received oral maropitant 8 mg or no treatment (control) 18 h before the administration of one drop of brimonidine solution in both eyes. Each cat was administered each of the two treatments, with a washout period of 1 week.

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Objectives: This study aimed to investigate the effects of intramuscular medetomidine and xylazine on tear flow in healthy cats.

Methods: Five cats each received medetomidine 10, 20, 40 and 80 µg/kg IM; xylazine 1.0, 2.

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Circulating microRNAs in the blood may provide diagnostic and prognostic information about canine neoplastic diseases, and their profiles may be conserved between human and canine species. We performed RT-qPCR to obtain the profiles of circulating plasma microRNA-214 and -126 in total 181 cases of canine neoplastic diseases and healthy controls. MicroRNA-214 levels were high in 2 epithelial tumours (thyroid and mammary carcinomas) and 4 non-epithelial tumours (osteosarcoma, histiocytic sarcoma, chondrosarcoma, and hemangiosarcoma).

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A 10 yr old intact female German shepherd dog presented with a large peripheral odontogenic fibroma and malignant melanoma on her lower jaw. The tumor was resected with a unilateral subtotal rostral hemimandibulectomy. After the mandible was removed, it was devitalized intraoperatively by freezing it in liquid nitrogen.

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Background: Leukemia/lymphoma cell lines have been critical in the investigation of the pathogenesis and therapy of hematological malignancies. While human LL cell lines have generally been found to recapitulate the primary tumors from which they were derived, appropriate characterization including cytogenetic and transcriptional assessment is crucial for assessing their clinical predictive value.

Results: In the following study, five canine LL cell lines, CLBL-1, Ema, TL-1 (Nody-1), UL-1, and 3132, were characterized using extensive immunophenotyping, karyotypic analysis, oligonucleotide array comparative genomic hybridization (oaCGH), and gene expression profiling.

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A 10-year-old castrated male Beagle dog was presented with a 2-month history of intermittent vomiting and abdominal pain. The dog was referred to the Veterinary Teaching Hospital at Iwate University for further evaluation, and a splenic tumour was suspected on the basis of ultrasonography and computed tomography. Surgery identified a large, solid, light-pink mass on the greater omentum with blood-coloured ascites in the abdominal cavity, and resection was performed.

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Malignant endothelial proliferative diseases including human angiosarcoma (AS) and canine hemangiosarcoma (HSA) are serious diseases with a grave prognosis. Establishing liquid biopsy-based biomarkers for screening has definite clinical utility; however, plasma miRNAs up- or down-regulated in these sarcomas have been unclear. For identifying possible diagnostic plasma miRNAs for these sarcomas, we investigated whether plasma miR-214 and miR-126, which miRNAs play important roles in angiogenesis and tumorigenesis, were elevated in malignant endothelial proliferative diseases.

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The pathogenesis of intervertebral disc (IVD) degeneration is not fully understood. The biomolecular signaling pathways involved in the IVD degeneration require further investigation. The aim of this study was to investigate the expression of NG2 proteoglycan in the degenerated IVD.

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Graft perfusion with cold heparinized saline has known to induce ischemia and reperfusion injury in feline kidney transplantation. In this study, the effects of phosphate-buffered sucrose solution and heparinized saline solution on early kidney graft function were compared in feline kidney autotransplantation. Perfusion of grafts with or without hypothermic storage with chilled phosphate-buffered sucrose solution prevented ischemia and reperfusion injury despite a very short ischemic time.

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Tacrolimus (Tac) is a core immunosuppressive drug in human organ transplantation. In feline kidney transplantation, however, the cost of Tac therapy is a significant obstacle. Clarithromycin (CLM) increases the blood trough level of Tac, effectively reducing the Tac dosage in human transplant patients.

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A 13-year-old castrated male miniature dachshund dog was presented with chronic vomiting and diarrhea. Contrast radiography and surgical exploration revealed an ileal cyst, which was excised. A diagnosis of epidermoid cyst was made from a combination of the clinical findings and histological examination of the surgical specimen.

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Phosphate-buffered sucrose (PBSc) solution is effective for short-term hypothermic preservation of tissue during feline kidney transplantation. A high-molecular-weight polyethylene glycol (35,000 Da, PEG35) reportedly enhanced the protective effects against cold-induced tubular injuries in animal kidney transplantation models. We investigated the ability of PBSc solution containing PEG35 to preserve cultured feline kidney cells using in vitro WST-8 cell proliferation assays.

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Clarithromycin (CLM) has been known to increase the cyclosporine (CsA) trough level in human and feline organ transplant patients. However, the interaction of CLM with CsA has not been reported in dogs. In this study, the effects of multiple dosing of CLM on the pharmacokinetics of CsA in three healthy beagles were investigated.

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A 12-year-old, 3.5-kg spayed female domestic shorthair cat had a tracheal mass identified as malignant B-cell lymphoma. The cat had tracheal resection and subsequently developed laryngeal paralysis.

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Methylxanthine derivatives increase cAMP and are known to have diuretic, cardiac, and central nervous system stimulatory effects. Moreover, caffeine inhibits the development of tumors induced by various carcinogens. The aim of this work was to elucidate the anticancer effects on apoptosis of xanthine derivatives alone and with doxorubicin in canine hemangiosarcoma cells.

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In humans, increased levels of GFAP in the CSF and blood have been reported with various neural diseases. However, there has been no study describing the usefulness of GFAP in the blood for disease of the spinal cord in dogs. The aim of this study was to describe the utility of GFAP in serum for a diagnosis of progressive myelomalacia.

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Five novel, canine lymphoma cell lines (Ema, CLC, CLK, Nody-1 and UL-1) were established from dogs suffering from lymphoma and characterized in vitro and in vivo. All cell lines, except CLC, were characterized with T-cell phenotypes, by flow cytometric analysis and polymerase chain reaction for antigen receptor rearrangement. Cell proliferation rates and transcriptional levels of MYC, PTEN, KIT and FLT3 varied between each cell line.

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Clarithromycin (CLM) has been known to increase the cyclosporine (CsA) trough levels in human transplant patients. However, the interaction of CLM with CsA has not been reported in cats. In this study, the effects of oral dosing of CLM on the pharmacokinetics and dosing of CsA in cats were investigated.

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