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Biomedical subjects

W Oh

Publications and source records attributed to W Oh.

At least 253 records · Page 14Linked to original sources

The preterm small-for-gestational age infant: a two-year follow-up study.

Previous investigators have reported unfavorable neurologic and developmental outcome of small-for-gestational age (SGA) infants (birth weight less than 1,500 grams born at term or at less than 30 weeks. of gestation. Since obstetrical considerations for the delivery of a SGA fetus often arise between 30 and 38 weeks, the outcome of these survivors becomes a relevant issue. In 1975 and 1976, twenty-eight of 47 such infants survived and 21 were followed sequentially during the first two years. Their birth weight was 1,220 +/- 195 grams (mean +/- S.D.) and the gestation 33.4 +/- 2 weeks. Each SGA infant was paired with a birth weight-matched appropriate-for-gestation (AGA) infant whose birth weight was 1,195 +/- 190 grams and gestation 29 +/- 2 weeks. The weight, length, and head circumference of the SGA infants attained the tenth percentile by 6 to 8 months and were similar to the AGA group. Quarterly neurologic examinations showed similar findings during the first year in the two groups. At 2 years, two SGA (diplegia) and one AGA (hemiplegia) infants were abnormal. The quarterly Bayley scores of the SGA infants were lower during the first 18 months but at 24 months, the two groups had similar scores. The favorable outcome in preterm SGA infants weighing less than 1,500 grams may serve as useful information in making clinical decisions for the management of mothers with suspected intrauterine growth retardation.

Child Development↗

Fructose-1,6-diphosphatase and glucose-6-phosphatase in newborn rats with intrauterine growth retardation.

The activities of two gluconeogenic enzymes, glucose-6-phosphatase and fructose-1,6-diphosphatase were examined in the normal and intrauterine growth retarded (IUGR) rat during the first 5 days of life. The fructose-1,6-diphosphatase activity, 1.54 +/- 0.10 mumol/min/g liver (means +/- SEM) in control and 1.47 +/- 0.20 in the IUGR rats, increased in both groups on days 2--4 but remained significantly lower in the IUGR rats through day 4 (4.53 +/- 0.6 mumol/min/g liver in control and 3.09 +/- 0.22 mumul/min/g liver in the IUGR rats, P less than 0.01). The glucose-6-phosphatase activity increased similarly in both groups. The weight of the IUGR rats remained lower through the third postnatal day (6.47 +/- 0.42 compared to 8.64 +/- 0.27 g in control rats). Blood glucose concentrations at birth were 117 +/- 11 mg/dl in control rats and 73 +/- 11 mg/dl in the IUGR rats (P less than 0.01). Although the glucose concentrations increased in both groups on days 2--4, the IUGR rats maintained relatively lower levels (P less than 0.01). The results indicate that IUGR fetal rats do not have augmented gluconeogenesis in spite of hypoglycemia. In addition, effective gluconeogenesis in the neonatal period appears to be delayed.

Animals↗

Increase in bilirubin binding to albumin with correction of neonatal acidosis.

Twenty-six serial measurements of free bilirubin concentration and apparent association constant of bilirubin for albumin (Ka) at a bilirubin: albumin molar ratio of 0.8 were performed and compared with baseline values in 11 newborn infants with acidosis before treatment and during recovery from acidosis. When arterial pH was corrected from 7.12 +/- 0.02 (Mean +/- S.EM.) to 7.34 +/- 0.02, there was a significant decrease in serum free bilirubin concentration and a significant increase in the Ka at molar ratio 0.8. The data offer in vivo evidence that correction of acidosis in the neonate results in an improvement of the apparent bilirubin binding affinity of albumin.

Acid-Base Equilibrium↗

Phosphoenolpyruvate carboxykinase in experimental intrauterine growth retardation in rats.

This study examines the role of impaired gluconeogenesis in the pathogenesis of neonatal hypoglycemia in intrauterine growth retardation (IUGR). IUGR was produced experimentally in eight pregnant rats by ligation of uterine arteries at the 17th day of gestation. Delivery occurred spontaneously at term. Sham operations were performed in five pregnant rats at the same gestational age and the fetuses delivered at term served as controls. The body weights of newborn rats with IUGR were significantly lower than the controls (5.32 +/- 0.12 vs. 6.22 +/- 0.06 g, mean +/- SE, P less than 0.001). The fetal liver weights were also significantly smaller in IUGR than in the control animals (0.224 +/- 0.14 vs. 0.340 +/- 0.12 g, P less than 0.001). The activity of phosphoenolpyruvate carboxykinase (PEPCK) (the rate-limiting enzyme of gluconeogenesis) in liver cytosols was significantly lower in rats with IUGR (0.06 +/- 0.01 vs. 0.11 +/- 0.02 microM phosphoenolpyruvate/g liver/min when compared with controls (P less than 0.05). A direct relationship between this enzyme and the birth weight was observed, suggesting a close relationship between intrauterine nutrition and the status of gluconeogenesis. The blood glucose level was also lower in growth-retarted fetuses (36.6 +/- 4.7 vs. 69.6 +/- 4.3 mg/dl, p less than 0.001) when compared with controls. The data suggest that gluconeogenesis is impaired in IUGR and is partly responsible for the increase in the incidence of neonatal hypoglycemia in this group of subjects.

Animals↗

Validity of endogenous creatinine clearance in low birthweight infants.

Despite methodologic problems, endogenous creatinine clearance is commonly used as an estimation of glomerular filtration rate (GFR). Inulin clearance was compared to endogenous creatinine clearance in a group of low birthweight infants to establish the validity of the latter. Thirty-three low birthweight infants (birthweight mean = 1600 g, gestational age mean = 33 wk) were studied between 10 hr and 10 days of age to simultaneously measure GFR by inulin and endogenous creatinine clearances. Inulin and creatinine clearances correlated directly (r = 0.738, P greater than 0.001). The slope of the regression line suggested an overestimation of GFR (inulin clearance) by creatinine clearance at the low GFR range and an underestimation at the high GFR range. The data were divided into two groups by the median inulin clearance (12.5 ml/min/1.73m2). The ratio of creatinine to inulin clearance was significantly higher in the low GFR group (1.28 +/- 0.16 vs. 0.89 +/- 0.04 SEM, n = 19, P less than 0.05). There was no difference between the two groups in plasma creatinine, birthweight, gestational age, incidence of respiratory distress, or oxygen requirements at the time of the studies. Endogenous creatinine clearance represents a good estimation of GFR (inulin clearance) in low birthweight infants. However, at the low GFR range, it represents an overestimation and at the high GFR range, an underestimation.

Bilirubin↗

Fluid and electrolyte balance in very low birth weight infants.

Correct fluid and electrolyte concentrations are essential to reduce mortality in critically ill infants. The authors list considerations in calculating the necessary maintenance volumes and emphasize the importance of continuous monitoring of data and a review and retabulation every eight hours, because requirements vary from one infant to the other, and in the same infant under different circumstances.

Electrolytes↗

Anatomic confirmation of echocardiographic measurements in neonatal hearts.

Significant correlations were demonstrated between echocardiographic measurements of left ventricular wall thickness, right ventricular wall thickness, septal thickness, left ventricular mass, aortic valve excursion, pulmonary valve excursion, mitral valve excursion, and tricuspid valve excursion and the same measurements made directly on the same hearts at autopsy. A new regression formula was derived for the calculation of echocardiographic right ventricular mass in life and was found to correlate significantly with right ventricular mass measured as the sum of right ventricular wall and septal volumes at postmortem examination.

Autopsy↗

Glycohemoglobin (HbAIc): a predictor of birth weight in infants of diabetic mothers.

Hemoglobins AIa-c (fast Hb), minor variants of HbA, are elevated in patients with diabetes mellitus. Recent studies indicate a relationship of fast hemoglobins, especially HbAIc (glycosylated form), to chronic hyperglycemia. Since infant oversize has been attributed to maternal hyperglycemia and fetal hyperinsulinemia, the hemoglobin HbAIc fraction was compared to birth weight (actual and relative to gestational age) and to maternal glucose tolerance. Normal (13), probably normal (8), gestational diabetic (10), and insulin-dependent women (14) were studied in the third trimester; women with advanced diabetic vascular disease were excluded. When corrected for gestational age, relative birth weights correlated in a significant linear regression with HbAIc (n = 45, r = 0.57, P less than 0.001). Third trimester maternal glucose tolerance (Kt) of women, not insulin dependent, correlated in a signigicant manner with both HbAIc (P less than 0.05) and birth weight for gestational age (P less than 0.01).

Birth Weight↗

The pharmacologic effects of furosemide therapy in the low-birth-weight infant.

The pharmacologic effects of furosemide were studied in six infants (mean gestation 30.7 weeks; mean birth weight 1,490 gm) at ages 10 to 57 days. Furosemide (for clinical indication, standardized at 1 mg/kg) was given intravenously over one minute; data were collected over the ensuing 24 hours. For three hours following furosemide administration, a significant diuresis was observed. Sodium excretion, percent fractional sodium excretion, and potassium excretion were significantly increased and urinary pH significantly decreased for six hours following the administration of furosemide. Creatinine and free water clearances were slightly elevated, although not significantly. Furosemide is an effective diuretic, the onset of pharmacologic action was within one hour, the peak action was sustained for three hours, and the duration of action was six hours. The net fluid, sodium, and potassium losses following a 1 mg/kg single dose were 28 ml, and 3.6 and 0.3 mEq/kg, respectively.

Furosemide↗