Boundary conditions for excitation propagation equations which do not distort the picture of impulse movement

New boundary conditions for the equations of excitation propagation are suggested. These conditions prescribe in the point in the end of the fiber the action potential which would be developed there, if half-infinite fiber would proceed further. The conditions suggested 1) in a number of cases allow to obtain an undistorted picture of excitation propagation, e.g. the picture when impulses fall out when a chain of impulses moves along the fiber; 2) save computer time and memory. Boundary conditions for syncitium and flat medium are considered.     

The ultrasonic diagnosis of acute thrombophlebitis of the vena saphena magna

A total of 321 patients with suspected acute thrombophlebitis were examined. There were 92 men (30%) and 229 women (70%). For control 15 patients without lower limb vein abnormalities and 19 ones with uncomplicated varicose disease were examined. Ultrasonic examinations using Ultramark-8 (Medata, Sweden) device were carried out in all the patients. Of the 313 cases (in 8 patients the diagnosis of acute thrombophlebitis was not confirmed by ultrasonic examination) ultrasonography results were erroneous in only 6 cases when assessing the proximal borderline of the great subcutaneous femoral vein thrombosis. Hence, the accuracy of duplex scanning in assessment of the proximal border of thrombosis in acute thrombophlebitis was 98.6% in our study. Ultrasonic angio-scanning in patients with superficial thrombophlebitis give reliable and valuable information about the presence, type, and extension of the pathologic process. This helps to optimally solve the therapeutic policy problems and adequately plan surgical intervention.     

Inhibition of mammalian protoporphyrinogen oxidase by acifluorfen

We have studied the kinetics of the inhibition of mitochondrial protoporphyrinogen oxidase (PPO) from liver and placenta of 3 mammalian species by the diphenyl ether herbicide acifluorfen (AF). AF competitively inhibited PPO from human liver and placenta, mouse liver and pig placenta with respect to its substrate protoporphyrinogen. In contrast, mixed-type inhibition was shown for pig liver. The differing results shown in pig liver may point to structural differences in PPO derived from different species and tissues. We have also compared the effects of AF on the function of PPO in human lymphoblasts from normal subjects and those with variegate porphyria, an inherited disorder of PPO. Competitive inhibition was shown for both and there were no significant differences in the values of Ks or Ki.