| Budget Amount *help |
¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1985: ¥3,300,000 (Direct Cost: ¥3,300,000)
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| Research Abstract |
The present study attempts to investigate the mechanism and site of intravascular hemolysis in canine dirofilarial hemoglobinuria (caval syndrome). Experiments using dye-enclosed erythrocytes could not identify the site of hemolysis because of low sensitivity. Therefore, fthe erythrocytes of a diseased dog labeled with 51Cr-sodium chromate were infused into the posterior vena cava, and blood was collected from the right atrium and right ventricle of the dog. In this experiment, results suggesting hemolysis near the tricuspid valve orifice were obtained in 3 of 4 hemoglobinuria cases. However, the amounts of hemolysis for some heartbeats would be very small. Though the technique using 51Cr is the most sensitive current method for detection of hemolysis, it may be insuficient for precise determination of the hemolytics site. For more reliable confirmation of the hemolytic site, further investigation shall be performed on a greater sample of diseased and control dogs using more sophysticated procedures.
On the other hand, the contributions to intravascular hemolysis of erythrocyte ATP contents, plasma phospholipid and bile acid concentrations, serum osmolality, disseminated intravascular coagulation and immunological mechanisms have been denied. Because of the abnormal lipid metabolism, erythrocytes tend to be injured easily. When heartworms were removed from the tricuspid valve orifice, the plasma hemoglobin concentration decreased rapidly. Besides, when the worms migrated to the tricuspid valve orifice, the plasma hemoglobin concentration increased. From the results in the present study and investigations up to this time, it was considered that the erythrocytes were destroyed by a physical mechanism near the tricuspid valve orifice in which heartworms were present.
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