In normal person, about 59% of total serum calcium is filtered into crude urine
. Then, 90% of those were reabsorbed by proximal tubules, henry loop, and early distal tubules and nearly 10% reabsorbed by early collecting ducts and late distal tubular.
The CRD test was performed using 0.45 cc of fresh crude urine
, and results were scored by trained clinical nurses at the bedside.
This may be particularly relevant for crude urine samples, which contain considerable amounts of cross-reacting substances and other structurally related compounds competing with the N45.1 antibody (i.e., 8-oxo-7,8-dihydroguanosine and 8-oxodGuo containing oligomers) (2).
(b) Recovery of 8-oxodGuo in urine was estimated by the addition of 8-oxodGuo in 5 different concentrations (2-50 [micro]g/L) to crude urine samples.
For the NMR analysis, we added 50 [micro]L of [sup.2][H.sub.2]O containing sodium-3-trimethylsilyl-[2,2,3,3 [sup.2][H.sub.4]]-1-propionate (TSP) to 0.5 mL of crude urine
as a chemical shift reference (b = 0.00).
In a 0.5-mL volume of crude urine
, 50 [micro]L of [sup.2][H.sub.2]O was added containing sodium-3-trimethylsilyl-[2,2,3,3[sup.2][H.sub.4]]-1-propionate (TSP) as a chemical shift reference (8 = 0.0).
One-dimensional spectra of the crude urine
were obtained by operating in the pulsed Fourier-transform mode with quadrature detection; there was a selective reduction in the TZ of the water protons by chemical exchange with N[H.sub.4]Cl (0.8 mol/L) and a saturation of the water signal.