[Relationship between the time of day of trauma infliction and the dynamics of endothelial mitotic activity].

Endothelial mitotic activity of the rabbit jugular veins depending on the daytime of trauma infliction was studied. In the first series of experiments (I), the operations were performed from 8 to 10 a. m., and in the second (II)-- from 8 to 10 P. M. After the operation one animal was killed every 3 hour, for 5 days. Mitotic activity (MK %) was studied continuously 8 mm from the wound edge in flat film preparations. The data obtained were statistically treated using approximation of the process course by the method of weighed sliding averages. Independently of the time of trauma infliction, the first mitoses in the endothelium appear after 21 h. Further, mitotic proliferation has a wavy character of different intensity in different tissue areas. Lack of similarity in the organism circadiam phase at the time of operation, produces distinct differences in the course of the process which are seen in asynchronity of the daytimes when the rise and recession of mitotic activity occur and in different length of these waves. In I series the length of these waves equals to 36, and in II series-- to 48 h. After the evening operation, 24-hour rhythm superimposed on its aliquat 48-hour activity is slearly seen. After the morning operation, daily rhythm is not observed. After the evening operation the process is more intense and has a greater length along the endothelial layer.