Uremia causes endothelial progenitor cell deficiency

BACKGROUND: Circulating bone marrow-derived endothelial progenitor cells (EPCs) promote vascular repair. Their number in peripheral blood correlates with endothelial function and cardiovascular risk in humans. We explored whether uremia influences the number of EPCs. METHODS: We assessed circulating CD34+ hematopoietic progenitor cells in whole blood using flow cytometry and EPCs (in vitro assay) in 46 patients with advanced renal failure and in 46 age- and gender-matched healthy subjects. Further, the effect of uremia on EPC differentiation was studied in vitro and in vivo. RESULTS: Both in renal patients (r= 0.34, P < 0.02) and in healthy subjects (r= 0.32, P= 0.04) the number of EPCs was significantly correlated to the absolute number of CD34+ hematopoietic progenitor cells. Renal patients had significantly fewer EPCs than healthy subjects, however (167 +/- 15 cells/high power field vs. 235 +/- 17 cells/high power field; P < 0.05). Uremic serum significantly (P < 0.05) inhibited EPC differentiation and functional activity in vitro. Amelioration of uremia after institution of renal replacement therapy in patients with terminal renal failure also significantly (P < 0.05) increased the number of EPCs. CONCLUSION: Uremia inhibits differentiation of EPCs. This may impair cardiovascular repair mechanisms in patients with renal failure.     

Clinical nerve conduction and needle electromyography studies

The electrodiagnostic study, consisting of nerve conduction studies and needle electromyography, is a useful adjunct to the clinical examination of the peripheral nervous system. The three types of nerve conduction study are motor, sensory, and mixed, of which motor is the least sensitive. Electromyography records the intrinsic electrical activity of muscle fibers, thus providing the physiologic status of muscle function. To interpret the electrodiagnostic study results, the clinician must understand the anatomic and physiologic basis of the studies. Peripheral nerve entrapment initially results in focal demyelination; thus, nerve conduction velocity slows across the site. However, with radiculopathy and nerve root compression, the nerve conduction study may be normal. Both nerve trauma and polyneuropathy show marked differences in their effect on the results of electrodiagnostic studies.     

Fibrinogen and high molecular weight fibrinogen during and after normal pregnancy

INTRODUCTION: Pregnancy has recently been described as a generalized intravascular inflammatory response to the conceptus. Total fibrinogen concentrations increase during pregnancy. The percentage high molecular weight fibrinogen (HMW-Fg) of the concentration total fibrinogen is known to increase during acute-phase conditions like inflammation. Therefore, we investigated whether the percentage high molecular weight fibrinogen increases during normal pregnancy. MATERIALS AND METHODS: Eighteen healthy nulliparous women with uncomplicated pregnancies with normal course and outcome participated in this study. Five blood samples were drawn from every woman in the gestational age periods 9 to 16, 17 to 24, 25 to 33 and 34 to 42 weeks and at 12 to 20 weeks after delivery. Total fibrinogen concentrations were determined according to Clauss and the percentage high molecular weight fibrinogen was assessed by SDS-electrophoresis and densitometry after isolation of fibrinogen by precipitation. One-way analysis of variance (ANOVA) was used to evaluate differences between gestational age periods and correlation coefficients were calculated by Pearson's method. RESULTS: Total fibrinogen concentrations increased with advancing gestational age and decreased after delivery. The percentage high molecular weight fibrinogen of the total fibrinogen remained unaltered during and after pregnancy. CONCLUSIONS: During normal pregnancy, there is an increase of total fibrinogen concentrations with advancing gestational age, without a rise in percentage high molecular weight fibrinogen. After delivery, the total fibrinogen returns to baseline concentrations.