KANAI Takao SCHOOL OF MEDICINE, TOKYO WOMENS MEDICAL UNIVERSITY, ASSISTANT PROFESSOR, 医学部, 講師 (60104642)
WATANABE Toshifumi SCHOOL OF VET. MED. AZABU UNIVERSITY, ASSOCIATE PROFESSOR, 獣医学部, 助教授 (10191777)
MUTO Makoto SCHOOL OF VET. MED. AZABU UNIVERSITY, ASSOCIATE PROFESSOR, 獣医学部, 助教授 (90130898)
|Budget Amount *help
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1999: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1998: ¥2,100,000 (Direct Cost: ¥2,100,000)
Canine mitral regurgitation(MR) is a high incident as aquired heart disease in small size aged dogs. Especially, Cavalier King Charles Spaniels(CKCS) is the most affected dog to the MR in US and Europe. The other hand, valvular changes of the human mitral value prolapse(MVP) is known as the myxomatous atrioventricular valvular degeneration by pathological findings. Those degeneration should also be the same findings in the dogs. In these circumstances, we tried to know the incidents of MR of CKCS as the first purpose of this study(1998). In the next step(1999), we also tried to know the difference of the collagen type of the canine mitral valve by using immunopathological methods.
[Results] In the first study(1998), 114 CKCS which were selected randomly were used to know the MR incidents.
1) 32 in 114 cases(28.1%) were diagnosed as MR, and it's ratio was a little higher than Maltese dogs of our previous data.
2) In the appearance age of MR, young CKCS which were under two years old, five
in 57 cases(8.8%) were diagnosed as MR(the youngest one was one year and eight months old). In up to 4 years old, 60% of CKCS were affected as the MR. It was found that CKCS had high incidents to the MR compared with the other small sized dogs(Maltese dogs).
3) In ECG findings, the higher amplitude of Q and R waves were found more than the other normal middle sized dogs.
4) In spite of the no murmurs, in echocardiogram, it was found that there were many morphological changes of the mitral valve. It's suggested that these cases will tend to change to the MR in the future. In the study of the next year(1999) in morphology and immunopathological findings of the mitral valve, 1) the breeding dogs, Pomeranian, Maltese, Beagle, CKCS and Shiba dogs were classified damages as light, middle and heavy. It's seemed that one Beagle and Pomeranian have had no change of the valves, and one Maltese and two Beagle had the light damages of the valve. Two Beagles and one CKCS were found the middle damages, and one Shiba dog had heavy damages of the valve by morphological findings. 2) From the light to middle damage groups of the mitral valve, in general pathological findings, a little desmoplasia of the valve was found, and the myxomatous valvular degeneration were also found a little in the same group. In the immunopathological findings, there was the collagen type III and IV in Pomeranian and CKCS, and type V in Beagle a little. Less