Biomedical subjects
K M Joos
Publications and source records attributed to K M Joos.
Flow field mapping in the anesthetized rat.
This study measured the hemodynamics of peripheral arterial sites in the rat, using 20 MHz pulsed ultrasonic Doppler velocimeter (PUDVM) methods. The lower extremities of 14 male Sprague-Dawley rats were studied. The targeted sites included the abdominal aorta, external iliac, proximal femoral, mid-femoral, and saphenous arteries. The hemodynamic variables of pulse period, maximum centerline velocity, lumen diameter, and mean volumetric flow were calculated interactively from temporal-spatial plots of local velocity distributions. An analysis of variance revealed significant differences between right and left sides for lumen diameter (P = 0.028) and mean volumetric flow (P less than 0.0001). The analysis showed no statistical difference for pulse period (P = 0.0836) among sites. However, three distinct groupings of sites: 1) abdominal aorta, 2) external iliac, proximal femoral, and mid-femoral arteries, and 3) saphenous artery were noted for the remaining hemodynamic variables (P less than 0.05). These results indicate that three hemodynamically distinct regions are available for microvascular research in the rat lower extremity arterial tree.
Microarterial synthetic graft repair: interstitial cellular components.
Although the histologic changes occurring during healing on the lumen surface of large vessel synthetic vascular grafts have been well characterized, the cells populating the interstices of microvascular grafts have not been examined in detail. Since microvascular grafts are required to provide vascular continuity under quite different physiological and hemodynamic conditions as compared with large vessel grafts, these interstitial cells within the synthetic graft material may also vary as a function of graft size. Monoclonal antibodies, light microscopy, and scanning and transmission electron microscopy were used in this study to identify the cells present within the 30-microns pores of 1-mm diameter polytetrafluoroethylene and replamineform silicone rubber grafts. Identified cells included few capillary endothelial cells enclosing erythrocytes, rare proliferating endothelial cells, few macrophages, rare foreign body giant cells, and a majority of fibroblasts. There was no evidence of smooth muscle cells or myofibroblasts within the interstices of these microvascular prostheses 12 weeks after implantation in the rabbit central ear artery. The graft types differed by the presence of foreign body giant cells and more densely packed collagen between cells in the replamineform silicone rubber graft interstices.
Peripheral hemodynamic stability during prolonged anesthesia in the rat.
The present study tests the hypothesis that peripheral hemodynamics in the rat femoral artery remain relatively stable during 3 hours of general anesthesia. Hemodynamic variables (pulse period, maximal centerline velocity, lumen diameter, and mean volumetric flow) were measured by the 20 MHz-pulsed ultrasonic Doppler velocimeter method at 30-minute intervals. The hemodynamic variables were not statistically different during the duration of the study. The mean values were pulse period 160 +/- 2 msec, maximal centerline velocity 37.0 +/- 1.9 cm/sec, lumen diameter 0.94 +/- 0.03 mm, and mean volumetric flow 1.92 +/- 0.19 cc/min.