Anatomical variation of arterial supply to the rabbit spleen

The rabbit, which is widely used as an experimental animal and is also popular as a companion animal, has a flat and elongated spleen with the longitudinal hilus running along its visceral surface. The spleen receives via the hilus an arterial supply that is essential for splenic nutrition and normal functioning. However, the distribution and variation of the arteries to the spleen have not been studied in detail. This study investigated anatomical variations of splenic arterial supply in 33 New Zealand White rabbits with a colored latex injection into arteries. We also examined whether the length of the spleen correlated with the number of the splenic branches of the splenic artery. The splenic artery always arose as the first independent branch of the celiac artery and ran along the splenic hilus to usually provide 6 (range, 3 to 10) splenic branches to the spleen. There was a moderate correlation (R=0.6) between the number of splenic branches and the longitudinal length of the spleen. The splenic branches often arose as a trunk or trunks in common with short gastric arteries. The number of common trunk(s) was usually 1 (range, 0 to 4). The data showed that the pattern and number of arterial branches to the spleen varied according to the individual animal, suggesting that such variations should be considered when performing experimental and veterinary surgical treatments in rabbits.     

Establishment of a Method to Measure Length of the Ulnar Nerve and Standardize F-wave Values in Clinically Normal Beagles

We designed a new method of measuring the length of the ulnar nerve and determining standard values for F-wave parameters of the ulnar nerve in clinically normal beagles. Nerve length must be precisely measured to determine F-wave latency and conduction velocity. The length of the forelimb has served as the length of the ulnar nerve for F-wave assessments, but report indicates that F-wave latency is proportional to the length of the pathway traveled by nerve impulses. Therefore, we measured the surface distance from a stimulus point to the spinous process of the first thoracic vertebra (nerve length 1) and the anterior horn of the scapula (nerve length 2) as landmarks through the olecranon and the shoulder blade acromion. The correlation coefficients between the shortest F-wave latency and the length of nerves 1, 2 or the forelimb were 0.61, 0.7 and 0.58. Nerve length 2 generated the highest value. Furthermore, the anterior horn of the scapula was easily palpated in any dog regardless of well-fed body. We concluded that nerve length 2 was optimal for measuring the length of the ulnar nerve.     

Histopathological changes in the pancreas due to decreased pancreatic blood flow in a canine tachycardia-induced cardiomyopathy model

In dogs, pancreatic acinar cell injury is thought to be caused by decreased pancreatic blood flow due to heart failure. In previous our report, it demonstrated that decreased heart function causes a significant decrease in pancreatic blood flow in heart failure dog model caused by rapid ventricular pacing (RVP). However, the types of histopathological changes remain unclear. We aimed to verify the types of histopathological changes occurring in the pancreatic tissue due to decreased heart function. After RVP for 4 weeks, atrophy of pancreatic acinar cells, characterized by a decrease in zymogen granules, was observed in all areas of the pancreas. In conclusion, the result of this study suggests that attention should be paid to ischemia/hypoperfusion injury in the pancreas.     

An epidemiological survey on pigs showing symptoms of infectious enteric diseases and dyspepsia in Japan

Diarrhea in pigs has the potential to have a serious economic impact on the swine industry. Previously, we suggested that the likely cause of the presence of non-infectious diarrhea in pigs characterized by lactate accumulation was dyspepsia. In this experiment, the prevalence of enteropathogens and hyper-lactate accumulation in feces of piglets in 4 distinct growth stages was examined. The feces were collected when veterinarian experts recognized abnormalities in sporadic outbreaks. Prevalence of enteropathogens in diarrheal feces was 100% in fattening pigs (FP), 75% in weaning pigs (WP), 50% in suckling pigs (SP), and 42% in growing pigs (GP). Prevalence of enteropathogens in loose feces was 53% in WP, 50% in SP, 40% in FP, and 28% in GP. Prevalence of hyper-lactate accumulation in diarrheal feces was 33% in GP, 33% in SP, 25% in WP, and 25% in FP. Prevalence of hyper-lactate accumulation in loose feces was 40% in GP, 0% in SP, 7% in WP, and 5% in FP. Accordingly, non-infectious dyspepsia is frequent in growing pigs. In this period, pigs are potentially exposed to needless antimicrobial therapeutic treatments in sporadic cases.     

Pathological and immunohistochemical features of 45 cases of feline meningioma

Meningioma is the most common primary brain tumor in cats, although there are few reports about their pathological features. To investigate the histopathological subtypes and immunohistochemical features including expression of cytokeratin and cell adhesion molecules, 45 cases of feline meningioma were examined. The mean age was 12.5 years (range 6–21 years). No statistically significant sex predilection was observed. Regarding the anatomical location of meningioma, tumors mostly developed in the cerebrum, followed by spinal cord and cerebellum, and multiple meningioma was observed in one cat. Microscopically, linear or focal mineralization was observed in 40 cases and cholesterol cleft was observed in 14 cases. Based on histopathological subtypes, there were 15 fibrous, 22 transitional, 2 meningothelial, 5 atypical, and 1 anaplastic meningiomas. These subtypes are classified into grade 1 (39 cases), grade 2 (5 cases), and grade 3 (1 case). There was no significant difference in the Ki-67 index among histological subtypes or grades. Immunohistochemically, the tumor cells were positive for cytokeratin in 5 cases (12.8%), vimentin in 17 cases (43.6%), E-cadherin in 36 cases (92.3%), β-catenin in 21 cases (53.8%), and N-cadherin in 1 case (2.6%), demonstrating the utility of E-cadherin-immunohistochemistry for the diagnosis of feline meningiomas.     

Color vision, accommodation and visual acuity in the largemouth bass

The largemouth bass is a sight feeder and one of the most popular freshwater fish for lure fishing. While lures a have variety of colors and forms, there is no information on the color vision and form perception in the largemouth bass. We recorded S-potentials from the isolate retinae of the largemouth bass to examine color vision electrophysiologically. The occurrence of the C-response provided direct evidence for the possession of color vision. L-responses recorded indicated a high spectral sensitivity to red. The direction and distance of lens movement of a specimen of 43 cm in fork length indicated a horizontal visual axis and the near point at 13.5 cm, respectively. The visual acuity calculated from the cone density and the focal distance of the lens was 0.10. Histological characteristics of the retina indicated that the eyes are well adapted to both form and movement perceptions.     

Methane emission from stored dairy manure slurry and slurry after digestion by methane digester

To examine the effect of storage temperature on the emission of methane (CH₄) and carbon dioxide (CO₂) and on recovery of nutrients from raw dairy manure slurry (RS) and slurry digested in a methane digester (DS), both slurries were stored in closed 100 L steel tanks under psychrophilic conditions (5, 10, 15 and 20°C) for a 150 day period. As the storage temperature increased, total methane emission increased in both types of slurry. The amount of methane emitted per unit of volatile solids of the RS and DS was 0.19 L/g and 0.10 L/g, respectively. The respective carbon dioxide emissions were 0.20 L/g for RS and 0.12 L/g for DS at 20°C of storage temperature. At temperatures greater than 15°C, the methane concentration in the emitted gas remained more than 40% of the total gas. During the experimental period, in excess of 90% of the total Kjeldahl nitrogen in these slurries was recovered (91.4–93.7% for RS and 93.7–98.4% for DS) after storage, and ammonium nitrogen was recovered in excess of 100% (100.1–143.2% for RS and 106.7–143.2% for DS storage tanks) because of the mineralization of organic nitrogen in the influent. These results indicate that manure slurry characteristics and storage temperature have significant impacts on methane emission. It can be concluded that on typical farms located in northern Japan, methane emission from manure storage tanks during late fall, winter and early spring may be negligible, because of manure temperatures less than 10°C. During late spring, summer and early fall, methane emissions can be substantially reduced by using underground storage to maintain lower manure temperatures.     

VIRTUAL ENDOSCOPY OF DOGS USING MULTI-DETECTOR ROW CT

Virtual endoscopy uses CT data to display hollow viscera such as the stomach, duodenum and colon as if by real endoscopic observation. The results are independent of the operator skill because virtual endoscopy does not require direct manipulation of endoscopic equipment. The purpose of this study was to evaluate the utility of virtual endoscopy in small animals. Ten beagles were examined by conventional endoscopy and virtual endoscopy using multidetector CT. Virtual images were image-processed at a workstation designed for depicting virtual endoscopy using CT data. Virtual images were visually comparable with conventional endoscopic images, especially in the area of the angular incisure and pylorus. The advantages of virtual endoscopy are observation from any viewing angle, a reduced learning curve for diagnostic interpretation, quantification of lesion size in three dimensions and a potential for reducing anesthesia time. The disadvantages of virtual endoscopy are a lack of color recognition information, an inability to retrieve biopsy samples, limited visualization of the duodenum, artifacts from respiration/peristalsis motion and an inability to observe function. Based on our results, we suggest that conventional endoscopy is still superior to virtual endoscopy in dogs. However, as technology improves, virtual endoscopy may emerge as a suitable alternative or adjunctive diagnostic tool for certain digestive disorders in small animals.