Intravascular granulocyte kinetic values of normal developing calves were determined, using the chromium radioisotope 51Cr as the cell label. A total of 15 kinetic trials were conducted in the calves at 8 to 365 days of age. The clearance of labeled granulocytes from the circulation was an exponential function. The kinetic data from the oldest group of calves (7 experiments on 5 calves, 180 days of age and older) were remarkably similar to those reported for persons. Mean total blood granulocyte pool was 6.34 x 108 granulocytes/kg of body weight, of which 45.6% was in the circulating granulocyte pool. Mean clearance half life (T 1/2) was 8.9 hr, and mean granulocyte turnover rate was 12.44 x 108 granulocytes/kg of body weight/day. In the oldest calf group, there was significant correlation between the blood granulocyte count and the total blood granulocyte pool size. There was also significant correlation between the total blood granulocyte pool size and the clearance half life. The youngest group of calves (4 experiments on 4 calves, 8 to 16 days of age) had significantly larger total blood granulocyte pool and shorter intravascular half life than did the oldest group. These factors combined to yield a markedly greater granulocyte turnover rate of 39.91 x 108 granulocytes/kg of body weight/day in the youngest group of calves. Calves of an intermediate group (70 to 127 days) had kinetic values which were intermediate between those of the youngest and oldest groups of calves.
|Original language||English (US)|
|Number of pages||5|
|Journal||American Journal of Veterinary Research|
|Issue number||4 I|
|State||Published - Dec 1 1975|
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