Quantitative electroencephalography of medetomidine,medetomidine-midazolam and medetomidine-midazolam-butorphanol in dogs

The purpose of this study was to evaluate the effects of the administration of an alpha2-adrenoceptor agonist alone and in combination with other derivatives on brain wave activity. In addition, the diagnostic values of the electroencephalogram (EEG) for judging the depth of the balanced anaesthesia with an alpha2-adrenoceptor agonist was evaluated. The treatments comprised 20 microg/kg medetomidine (Me-20), 80 microg/kg medetomidine (Me-80), 20 microg/kg medetomidine and 0.5 mg/kg midazolam (Me-Mi) administered intramuscularly, and 20 microg/kg medetomidine with 0.5 mg/kg midazolam and 0.1 mg/kg butorphanol (Me-Mi-Bu). The EEG was recorded continuously at pre-administration, and at 7, 10, 20, 30, 45 and 60 min after administration. The recorded data were analysed by separating the power spectrum into 1-3, 4-7, 8-13 and 14-30 Hz bands. Spectral-edge analysis was used to calculate the spectral edge frequency 90 (SEF90) and the median edge frequency (MEF). Time-related changes in power spectrum analysis showed a significant increase in the Me-80 group in the 1-3 Hz band. The power for 1-3 Hz in the Me-80 group was significantly higher than in all the other groups. In the 14-30 Hz band, there was a significant reduction of power in all groups following administration of the agents. The SEF90 frequencies were significantly reduced in all groups except for the Me-20 group after administration of the agents. The SEF90 frequencies in the Me-20, Me-Mi and Me-Mi-Bu were all significantly higher than those in the Me-80 group. However, there was no significant difference between the Me-20, Me-Mi and Me-Mi-Bu groups in any analyses. Our results demonstrated that the changes in quantitative EEG made by the Me-Mi-Bu and Me-Mi groups were similar to those made by Me-20 groups. Present results suggest that the EEG should be interpreted with caution in assessing the anaesthetic level in balanced anaesthesia in dogs.     

Effect of drug-eluting bead transarterial chemoembolization loaded with cisplatin on normal dogs

Transcatheter arterial embolization (TAE) and transcatheter arterial chemoembolization (TACE) are standard treatments for advanced hepatocellular carcinoma (HCC) and particularly for unresectable tumors or liver metastases in humans. However, reports on TACE used in veterinary medicine are few. This study aimed to evaluate the feasibility and safety of drug-eluting bead transarterial chemoembolization (DEB-TACE). We performed DEB-TACE in four clinically normal dogs and pharmacokinetically compared the results against hepatic arterial infusion (HAI) of cisplatin in two dogs. Drug-eluting beads (DEB) loaded with cisplatin were injected through a microcatheter for selective embolization of the left hepatic artery. After embolization, computed tomography (CT) images and histological examination findings were obtained during a 4-week observation period. Serum platinum concentrations were measured to evaluate cisplatin after each procedure. Biochemical analysis was performed during a 12-week observation period. Embolization was successful in all dogs, and there were no clinically apparent abnormalities. Embolization was confirmed up to 4 weeks after DEB-TACE in two of the four dogs and up to 1 week in the other two dogs using postoperative CT images. Cisplatin was not detected in peripheral veins in all dogs after DEB-TACE, but it was detected in trace amounts after HAI. DEB-TACE using cisplatin was safe and well tolerated by normal dogs. DEB-TACE may be useful in terms of determining systemic toxicity and drug concentration within tumors.     

Application of ventriculoperitoneal shunt as a treatment for hydrocephalus in a dog with syringomyelia and Chiari I malformation

A twenty-month-old Chihuahua male dog was presented to us suffering with ataxia. Based on the physical examination, X-ray and magnetic resonance imaging (MRI) examinations, we diagnosed the dog with hydrocephalus, Chiari I malformation and syringomyelia. Treatment consisted of internal medical treatment and the placement of a ventriculoperitoneal (VP) shunt. The ventricular dilatation was relieved and the dog improved neurologically; however, the Chiari I malformation and syringomyelia remained after surgically positioning the VP shunt.     

Expression of a tumor-associated antigen, RCAS1, in canine mammary tumors

Receptor-binding cancer antigen expressed on SiSo cells (RCAS1), one of novel cancer cell-surface antigens, is strongly expressed in invasive cancers. RCAS1 inhibits the in vitro growth of lymphocytes such as T cells and natural killer (NK) cells, and induces apoptotic cell death. We investigated the expression of RCAS1 in canine mammary tumor cell lines and tumor cells by immunohistochemistry, and also in situ deoxyribonucleic acid (DNA) fragmentation in tumor-infiltrating lymphocytes (TILs) by the terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate nick end labeling (TUNEL) method. All canine mammary tumor cell lines expressed RCAS1 at both the messenger ribonucleic acid (mRNA) and protein level. Immunohistochemically, RCAS1 was negative in 100% of normal mammary glands, but was expressed in 100% of malignant tumors examined. In most malignant mammary tumors, RCAS1 was localized in the cytoplasm with no polarity of expression. In benign mammary tumors, it was detected on the luminal surface of the tumor cell. RCAS1 expression or localization was significantly correlated with malignancy. In situ DNA fragmentation of CD3-positive TILs was observed in RCAS1-expressing tumors. RCAS1-expressing tumors, indicating a possible induction of apoptotic cell death in TILs through RCAS1 expression. These observations suggest that RCAS1 probably plays an important role in tumor progression and escape from immune surveillance in canine mammary tumors.     

Clinical features and their course of pituitary carcinoma with distant metastasis in a dog

An 11-year-old male toy poodle with neurological symptoms was diagnosed with a macroscopic pituitary tumor, which produced adrenocorticotropic hormone. Radiation therapy with a linear accelerator was performed for the pituitary tumor, and resulted in good local tumor control. However, serum endogenous adrenocorticotropic hormone concentrations were uncontrollable even after the tumor disappeared. Abdominal computed tomography revealed splenic masses, and splenectomy was performed. Histopathological examination of the surgical specimen showed tumor cells with eosinophilic and finely granular cytoplasm suggestive of endocrine origin. Since these cells were positive for adrenocorticotropic hormone, the case was diagnosed as a pituitary carcinoma with distant metastasis. Necropsy revealed multiple metastases to the abdominal organs. This is the first case report describing canine pituitary carcinoma with distant metastasis.     

TRANSORBITAL ECHOENCEPHALOGRAPHY IN CATTLE

The purpose of this study was establishment of the criteria of transorbital echoencephalography in cattle and experimental applications to bovine practice. Quantitative investigations using magnetic resonance (MR) imaging revealed that this examination could be applied to cattle under 3 months of age. The method of transducer positioning was established in Japanese Black (J.B.) and filial (F1) cattle (turning caudally at an angle of about 16 degrees and dorsally at an angle of about 23 degrees) or in Holstein cattle (turning caudally at an angle of about 20 degrees and dorsally at an angle of about 21 degrees). Examinations in clinical calves revealed that the cerebral parenchyma and the lateral ventricle could be detected antemortem or postmortem. In this study, the diagnoses of hydrocephalus or hydranencephaly was possible using antemortem transorbital echoencephalography. Transorbital echoencephalography was especially useful as the imaging method for bovine hydranencephaly.     

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.     

Usefulness of an early diagnosis for the favorable prognosis of fibrocartilaginous embolism diagnosed by magnetic resonance imaging in 10 Small- to Middle-Sized Dogs

Fibrocartilaginous embolism (FCE), a disorder of rapid onset featured by nonprogressive paralysis and paresis of four legs, shows clinical symptoms very similar to those of other disorders, e.g., disk herniation. We examined 10 animals diagnosed with FCE based on clinical symptoms and magnetic resonance imaging (MRI) findings in a retrospective study to examine the relationship between onset-to-diagnosis/treatment initiation time and prognosis of FCE. Statistical procedures, including Fisher’s exact probability test, were conducted. All animals in a group, in which the diagnosis was made and treatment was initiated after an elapse of <15 days after onset, showed improved symptoms; the group showed a positive correlation (r = 0.76) between “onset-to-symptom improvement time” and “onset-to-diagnosis/treatment initiation time”. Furthermore, the mean onset-to-diagnosis/ treatment initiation times were 2.67 days and 10.25 days in groups without and with sequelae, respectively; the time was significantly (P < 0.02) shorter in the group without sequelae. A significant difference was found between the groups in early diagnosis and treatment initiation. Our study indicates that the early precise diagnosis for acutely developed paralysis and paresis of four legs through testings including MRI, as well as the early onset of their treatment are important to obtain a favorable prognosis.     

Effects on the Local Immunity in the Testis by Exposure to Di-(2-ethylhexyl) Phthalate (DEHP) in Mice

Exposure to di-(2-ethylhexyl) phthalate (DEHP) has been reported to induce spermatogenic disturbance through oxidant stress and affect the immune system as an adjuvant. However, the effect of DEHP on the testicular immune microenvironment has not yet been investigated. In the present study, we examined the testicular immune microenvironment after exposure to doses of DEHP, previously identified as no-observed-adverse-effect levels. Adult male mice were administered food containing 0%, 0.01% or 0.1% DEHP and then testes were analyzed. The results showed that a slight but significant spermatogenic disturbance appeared in the 0.1% DEHP group but not in the 0.01% DEHP group at 8 weeks. It was also demonstrated that lymphocytes and F4/80- and MHC class II- positive cells were significantly increased with the elevation of IL-10 and IFN-γ mRNA expressions in the testes of not only the 0.1% DEHP group but also the 0.01% DEHP group at 8 weeks. Histochemical analyses involving horseradish peroxidase (HRP) as a tracer showed that a little blood-borne HRP had infiltrated into the lumen of a few seminiferous tubules beyond the blood-testis-barrier in both the 0.1% and 0.01% DEHP groups at 8 weeks. This indicates that a dose of DEHP that has little effects on spermatogenesis can change the testicular immune microenvironment with functional damage of the blood-testis barrier.     

Magnetic resonance imaging of syringomyelia in five dogs

This report describes the use of magnetic resonance imaging (MRI) in five dogs to diagnose spontaneous syringomyelia. Four of the dogs had cervical syringomyelia associated with hydrocephalus, and one of these cases was analogous to the Dandy-Walker syndrome in humans. The fifth dog had thoracic syringomyelia without hydrocephalus. It was possible to diagnose the condition antemortem in all of the dogs by MRI. It is suggested that MRI is a straightforward and effective tool for the antemortem diagnosis of syringomyelia in dogs.