Effects of smoking on blood pressure and proteinuria in patients with diabetic nephropathy.

OBJECTIVES: To investigate the effects of smoking on blood pressure and proteinuria in hypertensive diabetic patients with nephropathy. DESIGN: Controlled, randomized, cross-over study. SETTING: Tertiary care centre, University Hospital of Düsseldorf, Germany. SUBJECTS: A total of 25 subjects were recruited, each of whom smoked at least 20 cigarettes a day: 10 normotensive healthy volunteers and 15 hypertensive type 1 (insulin-dependent) diabetic outpatients with diabetic retinopathy and persistent micro- or macroalbuminuria; 10 diabetic patients had normal autonomic function test, whilst five patients showed signs of autonomic neuropathy. INTERVENTIONS: Controlled smoking or nonsmoking over a period of 8 h on separate days. MAIN OUTCOME MEASURES: Blood pressure was measured every 10 min with an automatic device and urine samples were collected every 3 h. RESULTS: Systolic blood pressure increased during smoking in controls (mean) (11.5 mmHg, P = 0.0001) and in diabetic patients without autonomic neuropathy (7.9 mmHg; P = 0.018), but not in patients with autonomic neuropathy (-2.4 mmHg; P = 0.792). Diastolic blood pressure increased during smoking in controls (6.2 mmHg; P = 0.019) but not in diabetic patients (2.5 mmHg; P = 0.204. 0.2 mmHg; P = 0.956). During smoking, median proteinuria and albuminuria increased in diabetic patients without autonomic neuropathy (8.1 mg mmol-1 creatinine, P = 0.002; and 2.6 mg mmol creatinine, P = 0.084). No significant changes in albuminuria or proteinuria occurred in the other two groups. CONCLUSIONS: Smoking increases blood pressure values in healthy subjects and in hypertensive patients with diabetic nephropathy and without autonomic neuropathy. This effect of smoking may be partly responsible for the faster progression of diabetic nephropathy in smoking diabetic patients.

Biotinyl-high-density lipoproteins as a probe for the determination of high-density lipoprotein turnover in humans.

A simple and reliable method has been developed for the determination of high-density lipoprotein (HDL) turnover in humans. In this method, complex formation of [14C]methylavidin with biotinyl-HDL3 and subsequent precipitation of excess [14C]methylavidin with biotinyl-silica-gel is utilized for the detection of as little as 0.1 microgram of biotinyl-HDL3 (by protein)/ml of serum with high precision and reproducibility, at 7.9 +/- 0.9% (n = 7) of the peptidyl lysine modified. In serial dilutions and quadruplicate determinations the intra- and interassay variations were less than 4.7% and 5.2%, respectively (n = 5). Recovery of biotinyl-HDL3 averaged 92 +/- 5.7% throughout the working range of the assay (n = 4). Variations in the levels of HDL or very-low-density lipoprotein (VLDL) did not interfere with the measurement of biotinyl-HDL3 in serum. Also, results were not affected by storage of serum samples at -80 degrees C for up to 4 weeks. After reinjection of autologous biotinyl-HDL3 (0.12 mg protein/kg body wt.) into five normolipidemic male volunteers, typical decay curves were obtained. The mean half-life of biotinyl-HDL3 was 5.1 +/- 0.5 days, no different from that reported for radiolabeled HDL or radiolabeled HDL apolipoproteins. Routine immunobinding analysis did not reveal formation of antibodies with specificity towards HDL 4 weeks after the reinjection studies. From this it appears that biotinyl-HDL3 is a suitable probe and a safe and reliable alternative for the determination of HDL turnover in humans when application of radiolabeled HDL is not desirable.