Assessing diastolic function with Doppler echocardiography using a novel index: ratio of the transmitral early diastolic velocity to pulmonary diastolic velocity

We developed a novel index to assess left ventricular (LV) relaxation as the ratio of transmitral early diastolic velocity to pulmonary diastolic velocity (E/D ratio). Mixed breed dogs (n=7) were anesthetized and their respiration was controlled. A 3.5-Fr micromanometer-tipped catheter was placed into the left ventricle. Dobutamine (5.0 or 10 microg/kg/min) or esmolol (100 or 500 microg/kg/min) was administered via the cephalic vein. The transmitral flow (TMF) and pulmonary venous flow (PVF) were recorded using transthoracic echocardiography from the apical long-axis view. The heart rate, systolic LV pressure, +dP/dt, and -dP/dt were significantly elevated by dobutamine, but significantly reduced by esmolol. Dobutamine significantly decreased tau, whereas esmolol significantly increased tau. The TMF-derived E and PVF-derived D wave velocities increased significantly with dobutamine, but decreased significantly with esmolol. A significant correlation was detected between the E and D wave velocities (r=0.92). Consequently, the E/D ratio was decreased significantly with dobutamine, and increased significantly with esmolol. Furthermore, the E/D ratio was significantly correlated with -dP/dt (r= -0.64) and tau (r=0.84). Our results suggest that the E/D ratio reflects LV relaxation, and may potentially provide further information on LV relaxation.     

Comparison of behavioral characteristics of dogs in the United States and Japan

This study examined the difference in dog owning between Japan and the United States, and the effect of these differences on dogs’ behavioral characteristics. Behavioral evaluations of privately-owned dogs were obtained by using online questionnaire. We compared background and demographic information from the two countries and analyzed the effects of these differences on behavioral characteristics in dogs. The results indicated that there was a bias in the dog breeds kept in Japan compared to the United States and that Japanese dogs’ body weight was lower than the US dogs. The main source of dog acquisition was pet stores in Japan and breeders and/or shelters in the United States. Multiple linear regression analysis found that Japanese dogs showed more aggression to household members and higher energy, restlessness and fear of non-social stimuli than US dogs, while US dogs showed more fear of unfamiliar persons, separation-related behavior and excitability. US dogs also showed higher levels of trainability and attachment to owners. The lower dog’s body weight was, the higher the behavioral scores except for trainability were. When dogs that were obtained under 3 months of age were analyzed, the younger the dogs were when their owners obtained them, the higher the scores on some behavioral problem factors were. The higher rates of problem behaviors among Japanese dogs compared with US dogs suggest that the preference for small breed dogs and poor early development environment influenced the behavioral characteristics of dogs.     

Epidural spinal myelolipoma in a dog

Epidural spinal myelolipoma was diagnosed in a 13-year-old, male Siberian husky that was referred for evaluation of progressive pelvic limb paresis and urinary incontinence. An epidural mass was detected by magnetic resonance imaging and computed tomography. The mass was removed and identified histopathologically as an epidural myelolipoma. Pelvic limb paresis improved after surgery, but urinary retention associated with neurological bladder dysfunction persisted.     

Estimation of heritability of vertebral number in chum salmon <Emphasis Type="Italic">Oncorhynchus keta</Emphasis>

Hereditary causes of variation in the vertebral number of chum salmon were analyzed to estimate heritability for populations in the Chitose and Shikiu Rivers, Hokkaido Island, northern Japan. A total of 70 families were produced by diallel cross mating and then heritability was estimated using two statistical tests: a two-way ANOVA and a parent-offspring regression. Heritability estimates ranged from 0.26 to 1.91 and showed a strong correlation between the values from the two different tests. Estimates from female components were substantially higher than those from male components, which can be attributed to the maternal effect. Heritability in the Shikiu River population was shown to be higher than that in the Chitose River population. These results indicate that the heritability of vertebral number in chum salmon is generally high, and also that vertebral number is controlled by hereditary causes.     

Evaluation of the air sac volume of penguins with respiratory diseases using computed tomography

Captive penguins with respiratory diseases exhibit advanced pathological conditions upon the appearance of clinical signs. Therefore, the successful treatment of respiratory diseases remains difficult after the onset of clinical signs, leading to high mortality rates. In this study, we measured air sac volume using computed tomography (CT) to evaluate the respiratory condition of penguins. In a regular quarterly health checkup, blood samples were collected from 45 penguins housed at an aquarium in Hokkaido, Japan. A total of 12 penguins with abnormal blood parameters underwent CT. The air sac volumes were calculated in three-dimensional CT, and the scatter plots of the air sac volumes and body weights were analyzed. No correlation was found between the air sac volume and body weight in both the gentoo and king penguins. Two gentoo penguins with infiltration and one king penguin with multiple nodules on CT were tentatively diagnosed with aspergillosis and treated with oral administration of itraconazole. Follow-up CT examination was performed until the outcome: healed or died. The mean air sac volumes of the two gentoo penguins, which recovered after treatment, increased from 273.9 and 329.0 cm³ before healing to 449.0 and 424.6 cm³ after healing, respectively. Meanwhile, the air sac volume of the king penguin, which subsequently died, decreased from 1,556.9 to 920.6 cm³ despite treatment. Changes of the air sac volume in the same individual could be useful for evaluating the respiratory condition of penguins.     

A comparison between injection speed and iodine delivery rate in contrast-enhanced computed tomography (CT) for normal beagles

The purpose of this study was to compare between the injection speed and iodine delivery rate in order to establish a concept for reproducible contrast timing in contrast-enhanced computed tomography (CT) for small animals. Clinically healthy beagle dogs were administered a nonionic iodinate contrast medium at a dose of 800 mgI/kg; they were divided into 3 groups (n=5, crossover method): in one group, the injection speed was fixed at 1.0 ml/sec, and in the second and third groups, the iodine delivery rate was fixed (the injection durations were 30 and 60 sec, respectively). The variation in scatter of the time to aortic and hepatic peak enhancement in the fixed iodine delivery groups was lower than that in the fixed injection speed group. These results suggest that in contrast-enhanced CT for small animals, the contrast medium should be injected at a fixed iodine delivery rate in order to provide reproducible contrast timing.     

Brain abscess in a Japanese black calf: utility of computed tomography (CT)

Computed tomography (CT) was used for diagnosis of brain abscess in a 6-month-old, Japanese black calf presented with neurological dysfunction, compulsive circling and vision disturbance. CT images showed asymmetric lateral ventricles, and presence of intra-cranial multiple low absorption lesions surrounded by capsule suggestive of abscess in the right cerebral hemisphere. Postmortem examination revealed marked swelling of right cerebral hemisphere and olfactory bulb. Multilocular large abscess containing creamy pus was found to occupy most area of periventricular and lateral ventricle. Fusobacterium necrophrum was isolated from the abscess contents as the causative agent. These results demonstrate that CT is useful tool for tentative diagnosis of bovine brain abscess.