Is serum paraoxonase 1 ( PON1 ) lactonase activity lower in end-stage renal disease patients than in healthy control subjects and increases after hemodialysis?
ESRD patients maybe more susceptible to lipid peroxidation and to protein homocysteinylation than healthy subjects due to the decreased activity of lactonase. A lower serum lactonase activity would be coupled with delayed catabolism of oxidized phospholipids in low-density lipoprotein and oxidized macrophages, and with greater protein homocysteinylation, accelerating atherogenesis. One mechanism for lower lactonase activity in ESRD patients may be inhibition by uremic toxins and oxidative stress. The pathophysiology of reduced lactonase activity in uremia and the beneficial effects of HD need further investigation.
We demonstrate a substantial difference in the position of the aorta relative to the spine in prone and in supine position, which is most markedly seen at levels T4 to T8. The aorta is positioned posterolateral to the spine in supine position and more anteromedial in prone position. Before performing anterior thoracolumbar spine surgery, we suggest to measure vertebral body width, as well as the position of the aorta in the prone and in the supine patient to decide if his approach is technically feasible, or if an alternative (contralateral) approach is preferable.