Postnatal change of renal artery blood flow velocity and its relationship with urine volume in very low birth weight infants during the first month of life.

Although the renal artery blood flow velocity has been investigated recently using the ultrasound Doppler method, little is known about the longitudinal change of renal artery blood flow velocity and its relationship with urine volume in very low birth weight infant. Thus, we measured renal artery blood flow velocities by means of the pulse Doppler method in 28 very low birth weight infants. Maximum, minimum, and mean blood flow velocities were determined at postnatal days 0, 1, 2, 3, 4, 5, 6, 13, 20, and 27. The resistance index was also calculated. The maximum and mean blood flow velocities increased gradually after birth, and were significantly higher at 13, 20, and 27 days after birth. The minimum blood flow velocity and the resistance index were relatively constant during the study period. The mean blood flow velocities were also analyzed for any correlation with urine volume. There was a poor correlation between urine volume (ml/kg/day) and mean blood flow velocity (cm/s) (Y = 2.38X + 57.4, Y: urine volume, X: mean blood flow velocity, n = 161, r = 0.338, P < 0.01). However, if the mean renal artery blood flow velocity was less than 10 cm/s, oliguria was observed in most cases. The measurement of the renal artery blood flow velocities appears to be useful in understanding the background condition of renal function in very low birth weight infants.

[Enzyme immunoassay of 17-hydroxyprogesterone in dried blood spot on filter paper using specific antibody for 17-hydroxyprogesterone].

Specific antiserum for 17-hydroxyprogesterone (17-OH-P) was prepared by immunizing 7 alpha-(2-carboxyethylthio)-17-OH-P conjugated bovine serum albumin (BSA) in rabbits. Using this antiserum, 17-OH-P enzyme immunoassay for dried blood spots on filter paper was established. As a label, alkaline phosphatase was coupled covalently with 7 alpha-carboxy-methylthio-17-OH-P by carbodiimide method. B/F separation was carried out by the addition of anti-rabbit IgG goat antiserum. All specimens used were punched out with a paper puncher of 3mm diameter. The assay sensitivity was 2pg/tube, which was estimated by two standard deviation at zero concentrations of the calibration curve. Cross reactivities of this antibody were as follows: 11-deoxycortisol (8.21%), 17-OH-pregnenolone (3.33%), progesterone (1.67%), 11-deoxycorticosterone (0.31%), cortisol (0.16%), pregnenolone-3-sulfate Na salt (0.03%), dehydroepiandrosterone (DHEA) (less than 0.03%), 16 alpha-OH-DHEA (less than 0.03%), DHEA-3-glucuronide (less than 0.03%), DHEA-3-sulfate Na salt (less than 0.03%), pregnenolone (less than 0.02%). Intra- and inter-assay coefficient of variations were 4-14% and 9-18%, respectively. In normal babies, 17-OH-P concentrations measured directly (without sample extraction) were below 23pg/disk (n=204). The histogram of 17-OH-P level in normal babies obtained by the direct method was distributed lower than that obtained by the enzyme immunoassay system (range: 4-79pg/disk, n=268) which used antibody raised against 17-OH-P-3-O-carboxymethyloxime conjugated BSA (Enzaplate, Sapporo Diagnostic Laboratory).(ABSTRACT TRUNCATED AT 250 WORDS)