Pathological and immunological findings of athymic nude and congenic wild type BALB/c mice experimentally infected with Neospora caninum.

Neospora is a cyst-forming coccidian parasite that causes abortions and neuromuscular disorders in a wide variety of mammals. Japanese bovine isolate JPA1 was inoculated intraperitoneally into BALB/c nu/ nu (athymic nude) and BALB/c (congenic wild type) female mice to examine the distribution of parasites and resistance mechanisms to Neospora infection. All the athymic nude mice died within 28 days after intraperitoneal injection of 2 x 10(5) JPA1 tachyzoites, whereas all the congenic wild type mice survived without exhibiting any clinical signs. Tachyzoites were identified in the uterus and pancreas and later spread to many other organs. Most tachyzoites identified in the necrotic foci were localized in the epithelium of the venules and capillaries. Nude mice developed high level of serum interferon-gamma and interleukin-6 as infection proceeded. Inflammatory response to Neospora infection might be mediated by Th1-type dependent cellular immunity.     

Partial bladder resection in a bitch with urinary retention following surgical excision of a vaginal leiomyoma

Ovariohysterectomy and surgical excision of a vaginal leiomyoma were performed in a bitch exhibiting continuous bleeding from the vulva. Following excision of the tumour, urine retention and urinary incontinence developed. Treatment using drugs and an indwelling catheter was unsuccessful in correcting the disorders and chronic cystitis developed after long-standing urine stagnation in the bladder. The authors resorted to undertaking partial cystectomy in order to correct the condition, which resulted in reduced urine retention and improved micturition.     

Relationship between monensin and sulphur amino acid requirements IN broiler chickens

1. Diets containing 80, 100, 125, 150, 175 or 200 mg monensin/kg were fed to broiler chickens from 0 to 28 d in cages that prevented access to excreta.

2. Growth was depressed with 125 mg monensin or more/kg and food intake tended to decrease. Feathering was adversely affected with 175 mg or more/kg.

3. In a similar experiment, diets containing 8.8, 9.1, 9.4, 9.7 or 10.1 g total sulphur amino acids (SAA)/kg were supplemented with 125 or 80 mg monensin/kg and compared with a diet containing 8.8 g SAA and 33 mg robenidine/kg.

4. With 125 mg monensin/kg, body‐weight gain was significantly less than that of birds receiving robenidine if dietary SAA content was 9.4 g or less/kg. With 9.7 g SAA or more/kg, gain in birds receiving monensin was similar to that of birds receiving robenidine.

5. Monensin at 125 mg/kg therefore appears to increase the SAA requirement.     

An experimental study of apico-aortic valved conduit (AAVC) for surgical treatment of aortic stenosis in dogs

A new valved conduit was developed using a canine aortic valve. The bioprosthetic valve was fixed with glutaraldehyde and epoxy compound (Denacol-EX313/810). A vascular graft composed of ultra-fine polyester fiber (10 mm in diameter, 200 mm in length) was used. Four dogs underwent apico-aortic valved conduit (AAVC) implantation and aortic banding (bypass group, BG), while another 4 dogs underwent aortic banding without AAVC implantation (control group, CG). Cardiac catheterization and angiocardiography were performed for assessment of hemodynamics 2 weeks and 6 months after surgery. Left ventricular systolic pressure, left ventricular end-diastolic pressure and the left ventricular-aortic pressure gradient differed significantly (P<0.01) between the BG and CG dogs. Left ventricular angiocardiography showed patency of the valved conduit in all the BG dogs. Echocardiography was performed before and 2, 4 and 6 months after surgery, and showed that while pressure overload caused concentric myocardial hypertrophy in the CG dogs, the left ventricle dilated eccentrically in the BG dogs. Furthermore, relief of left ventricular pressure overload by AAVC was maintained.     

Loss of milk yield due to Akabane disease in dairy cows

Akabane disease is an infection with clinical signs of congenital malformation and abortion in ruminants. Abnormal parturitions caused by Akabane disease result in great economic loss. The purpose of this study is to estimate the reduction in the milk yield from abnormal parturition due to Akabane disease. The data were collected from 33 Holstein cows on 11 farms. The animals had abnormal parturitions during the period from September 1998 to March 1999, and were diagnosed as having Akabane disease. The mean and standard deviation of the rate of reduction in the milk yield of 33 cows after abnormal parturition caused by Akabane disease was -11.4 +/- 14.9%. The means and standard deviations of the rate of reduction of four cows calving abnormally at 220-239 days of gestation, nine cows calving abnormally at 240-270 days of gestation, and 20 cows calving abnormally at 271-300 days of gestation were -26.6 +/- 24.7%, -14.7 +/- 11.0%, and -6.9 +/- 12.3%, respectively. In this study, we demonstrated that the rate of reduction in the milk yield in cows affected by Akabane disease was -11.4 +/- 14.9%, but values as high as -26.6 +/- 24.7% were reached in the comparison with the milk yield obtained after normal parturition.     

Percutaneous transcatheter coil embolization of a ventricular septal defect in a dog

A 4-month-old male French Bulldog weighing 5.0 kg (11 lb) was referred for a heart murmur. A grade 3/6 systolic murmur was detected at the left heart base and a grade 4/6 systolic murmur was detected at the right heart base. By use of color-flow Doppler ultrasonography and cardiac catheterization, a diagnosis of supracristal ventricular septal defect (VSD) with accompanying aortic regurgitation was made. Percutaneous transcatheter coil embolization was used to close the VSD. Because residual shunt was detected via echocardiography after coil implantation, the residual shunt was followed periodically via echocardiography to detect spontaneous closure of the VSD. Volume overload in the left ventricle was detected in the dog 131 days after admission. Additional coils were placed 137 days after admission. Hemolysis resulting in hemoglobinuria was detected, but this complication was mild. In the dog of this report, results of coil occlusion for correction of VSD were promising. Thus, coil occlusion should be considered as an alternative treatment for VSD in dogs.     

A quantitative assessment of the risk of exposure to bovine spongiform encephalopathy via meat-and-bone meal in Japan

The feeding of meat-and-bone meal (MBM) derived from cattle infected with bovine spongiform encephalopathy (BSE) is a major source of BSE infection. The risks of BSE infection via MBM in Japan were examined quantitatively to estimate infectivity to cattle via MBM derived from a single clinically infected animal being rendered. Three routes of exposure were modeled: (i) feeding cattle concentrates containing MBM as an ingredient, (ii) feeding cattle concentrates contaminated with MBM from non-ruminant feed at feed plants and (iii) directly feeding MBM in supplemental form to cattle on farms. The effectiveness of measures designed to restrict the feeding of ruminants with ruminant MBM (feed restriction) as well as differences in the risk of exposure among regions were examined using the model.

The model revealed that the median total infectivity fed to dairy cattle via MBM derived from one infected animal was approximately 0.49 cattle oral ID₅₀ (5th percentile = 0.43 ID₅₀, 95th percentile = 0.54 ID₅₀). This value was reduced by 55% after the addition of MBM to cattle concentrates was restricted in 1996. The risk of exposure in dairy cattle was twice that in beef cattle. Comparisons of regional differences in exposure risk indicated that the risk was highest in a region where 14 of the 20 BSE cases reported to date were born. Our model suggested that the routes of exposure via MBM were unlikely to result in increased propagation of BSE in Japan. Furthermore, despite some regional variation, the risk of exposure declined further after the feed restriction was imposed in 1996.     

Cardiac remodeling and angiotensin II-forming enzyme activity of the left ventricle in hamsters with chronic pressure overload induced by ascending aortic stenosis

Cardiac remodeling and angiotensin II-forming enzyme activity of the left ventricle on chronic pressure overload were studied in male Syrian hamsters, whose chymase activity is similar to that of dogs. Pressure overload was achieved by banding at the ascending aorta (aortic stenosis). Echocardiography, histological analysis, and analysis of cardiac angiotensin-converting enzyme and chymase-like activities were performed. At 10 weeks after banding, concentric hypertrophy of the left ventricle was evident. At 20 weeks after banding, the ventricular weight-to-body ratio, cardiac fibrosis, and cardiac chymase-like activity were significantly increased, while cardiac angiotensin-converting enzyme activity was significantly decreased. This suggests that cardiac chymase, compared with cardiac angiotensin-converting enzyme, was activated against the chronic pressure overload and was responsible for the cardiac remodeling through the formation of angiotensin II. Considering the utility of the rodents, the interspecies similarity of the Ang II-forming pathway, and the effect of chymase in the hamsters, the present model is considered useful for studies evaluating the effect of Ang II and chymase in the canine heart with chronic pressure overload.     

Increases in pig major acute-phase protein in wasting pigs brought to the abattoir

Plasma proteins of wasting pigs were quantitatively and qualitatively compared with those of normal fattening pigs. Higher expression of a 120 kDa protein was observed in the plasma of wasting pigs by SDS-PAGE. This protein was identified as pig major acute-phase protein (Pig-MAP) by proteomic analysis using two-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The plasma concentration of Pig-MAP in wasting pigs was 7-fold higher than that of normal ones.