We exploited the concentration dependence of hemoglobin S on its solubility in concentrated phosphate buffer to determine the percentage of hemoglobin S or hemoglobin A in whole blood or hemolysates. A sample is incubated for 1 h at 37 degrees C in "SickleQuik" (General Diagnostics) tubes, and the absorbance of the aqueous phase is then measured at 555 nm and 650 nm, the latter wavelength to correct for turbidity. The fractional hemoglobin S or hemoglobin A content is read from standard-curve data on mixtures of hemoglobin A and hemoglobin S. Such curves can be prepared with the use of hemoglobin A alone, because under our conditions all hemoglobin S is precipitated. The curve is reproducible for up to three weeks. Day-to-day CVs ranged from 1.8% at 10% hemoglobin S to 8.1% at 68% hemoglobin S. For similar concentration ranges, day-to-day CVs for electrophoresis, with densitometry, ranged from 4.9% to 18%. Results on 29 patients are presented. We recommend the method for rapid quantification of hemoglobin S percentage for patients with sickle cell disease in acute-care situations.

As an index of fetal lung maturity, the ratio of total surface-active phospholipid (phosphatidylethanolamine + phosphatidylinositol + phosphatidyglycerol + lecithin) to sphingomyelin performs as well as or better than any other indicator that we tested, showing 92% sensitivity and 98% specificity. The sensitivity and specificity, respectively, of the other methods were: (a) lecithin/sphingomyelin ratio, 92% and 95%; (b) alkaline phosphatase/glutamyltransferase ratio, 100% and 49%; (c) microviscosity, 75% and 97%; and (d) adsorbance at 650 nm, 50% and 73%. The procedure requires 2 h or less and its simplicity allows it to be offered on a 24 h/day basis without necessitating special training.

Sane , Saito H: Endogenous glucose production and glucose effectiveness in type 2 diabetic subjects derived from stablelabeled minimal model approach.

To study the effect of fatty acid chain saturation on the fluorescence polarization assay as a measure of fetal lung maturity, we used purified phospholipids isolated from human amniotic fluid and various commercial phospholipids. We found that the fluorescence polarization value decreased as the concentration of unsaturated fatty acids increased. In contrast, the lecithin/sphingomyelin ratio increases with increasing amounts of saturated lecithin, produced as the fetal lung matures. Since only saturated lecithins are surface active, the two indices of fetal respiratory status must reflect different properties of lung surfactant.

No abstract