Biomedical subjects

W Oh

Publications and source records attributed to W Oh.

At least 163 records · Page 9Linked to original sources

PubMed1986

The Apgar score revisited: influence of gestational age.

We tested the hypothesis that Apgar scores are in part related to the newborn infant's level of maturity. Seventy-three pregnant women with normal fetuses of gestational age 22 to 42 weeks were studied. Fetal well-being was documented by a prospectively designed recording of pregnancy history, labor complications, and birth outcome, including cord blood pH and base deficit measurements. The 1- and 5-minute Apgar scores were directly related to gestational age. Respiratory efforts, muscle tone, and reflex were the major determinants for a decreasing Apgar score with declining gestational age. We conclude that the 1- and 5-minute Apgar scores are influenced by the infant's level of maturity and that our data may be useful in evaluating the true value of Apgar scores in assessing the fetal and neonatal condition of low birth weight infants.

Apgar Score↗

PubMed1986

Neonatal polycythemia and hyperviscosity.

The combination of polycythemia and hyperviscosity in the newborn is a common problem. The incidence will vary depending on the environment and population involved because factors such a high altitude and high-risk pregnancies will markedly influence the incidence of this complication. The timing of the cord clamping at birth in a vaginally delivered infant also will make a difference with regard to the incidence of polycythemia and hyperviscosity. The pathogenesis of polycythemia and hyperviscosity is probably multifactorial and may involve events occurring during prenatal, intrapartum, and the immediate postnatal period. Polycythemia and hyperviscosity affect many organ systems. Therefore clinical manifestations are frequently nonspecific. All infants with symptomatic polycythemia and hyperviscosity should receive a partial exchange transfusion. The management of asymptomatic cases is controversial and must be individualized. The prognosis of infants with polycythemia and hyperviscosity depends heavily on the primary cause of polycythemia and hyperviscosity. Those neonates with symptoms that may or may not be related to polycythemia and hyperviscosity itself generally will have less favorable outcomes if partial exchange transfusions are not performed. The outlook of the asymptomatic polycythemia and hyperviscosity is less certain and remains to be explored.

Animals↗

PubMed1986

Growth and fatty acid metabolism in experimental intrauterine growth retardation: effect of postnatal nutrition in rat.

Rats, 3 1/2 to 4 d of age, were used to study weight gain and fatty acid (FA) metabolism as a function of degree of intrauterine growth retardation (IUGR) and of postnatal nutrition. The IUGR, quantified postnatally as mild and severe, was produced by uterine artery ligation on d 17 of gestation, and controls were shamoperated. Food intake was manipulated by varying the litter size; i.e., pup number per dam was 4 or 5 for overfeeding, 8-10 for normal feeding and 13-15 for underfeeding. Fatty acid synthesis rate (FASR) (determined by tritiated water incorporation in FA) and contents were determined in selected organs at 84 to 96 h of age. The initial weights (grams) at 2 to 12 h of age were: 5.88 +/- 0.74 (mean +/- SD) for controls, 5.18 +/- 0.11 for mild IUGR and 4.18 +/- 0.24 for severe IUGR. During the first 96 h of life, weight gain was less in underfed control pups while overfeeding resulted in the same weight gain as in normally fed pups. Pups with mild IUGR showed the same effect of under- or overfeeding as control pups. In the severe IUGR groups, weight gains were similar in all three feeding groups. In the carcass, the fatty acid content was reduced as a result of both prenatal and postnatal undernutrition. Although the underfed control group had a high FASR, underfeeding had no effect on the FASR of groups with IUGR. In the liver, the FA content was also lower in the underfed controls and in IUGR groups, without any difference in FASR. Feeding did not influence the FASR of liver.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1986

Maternal and environmental factors affecting developmental outcome of infants of adolescent mothers.

The effect of maternal and environmental factors on the developmental outcome of infants with low medical risk born to adolescent and non-adolescent, primiparous, Caucasian mothers was studied. Twenty-one were adolescent mothers (less than or equal to 17 years of age) and 21 were non-adolescent (21-29 years of age). Assessment of child care support, life stress, and home environment were carried out at 4 months. Infants were examined at 8 months, and child care support and life stress were reassessed. Adolescent mothers reported less child care support at both 4 and 8 months and more life stress at 8 months than non-adolescent mothers. Adolescent mothers were also found to be less responsive, used restriction and punishment more often, and were less involved with their infants during the home observation. Infants of adolescent mothers had lower Bayley Mental Development Indices at 8 months. A theoretical model, whereby the mother's age, education, and socioeconomic status (SES) were conducive to less optimal child care support and life stress, which in turn affected the infant's cognitive status, was supported by this data. Thus, within a low medical risk population, we have documented the significant role of maternal and environmental factors in determining the infant's cognitive status.

Adolescent↗

PubMed1986

Regional blood flow in newborn piglets during environmental cold stress.

Regional blood flow, oxygen delivery, and vascular resistance were determined in newborn piglets during a successful homeothermic response to environmental cold stress. Eight 3- to 4-day-old awake piglets were studied in a thermoneutral environment and 30, 45, and 60 min after onset of environmental cold stress. During cold stress, blood flow was significantly increased to skeletal muscle, the thermogenic organ, and decreased to the small intestine (P less than 0.05). Because arterial oxygen content (CaO2) was stable during the study, changes in oxygen delivery (CaO2 X blood flow) paralleled blood flow. Vascular resistance during cold stress was significantly decreased in skeletal muscle and increased in both the adrenals and the small intestine (P less than 0.05). We conclude that, during successful thermogenesis, the redistribution of cardiac output toward the thermogenic organ (skeletal muscle) is associated with a significant decrease in intestinal blood flow and oxygen delivery. This is not a passive process as evidenced by the coincident observation of increased intestinal vascular resistance.

Animals↗

PubMed1986

Age of diphtheria, tetanus, and pertussis immunization of special care nursery graduates.

Diphtheria, tetanus, and pertussis (DTP) immunization data were collected on 103 special care nursery graduates in our neonatal follow-up clinic to determine whether DTP immunization schedules were significantly delayed relative to recommendations of the American Academy of Pediatrics (2, 4, and 6 months for DTP 1, 2, and 3, respectively). An inverse correlation was found between birth weight and immunization for first, second, and third DTP (r = 0.319, P less than .01; r = .205, P less than .05; and r = .236, P less than .05, respectively). We subsequently conducted a mail survey to determine the DTP immunization policy present in effect in 25 neonatal intensive care units in the United States and Canada. The survey indicates that procedural approaches remain markedly heterogeneous, and 10 of 25 (40%) units have no existing policy for implementation of DTP immunization. These data suggest that special care nursery populations are at potential risk for pertussis, which requires a conscious implementation of DTP immunization by the special care nursery, the follow-up clinic personnel, and the primary care physician.

Birth Weight↗

PubMed1985

Postnatal growth and fatty acid synthesis in overgrown rat pups induced by fetal hyperinsulinemia.

Fetal hyperinsulinemia in the rat results in increased body weight, lipid content, and enhanced lipogenesis in liver and carcass. The purpose of our study was to determine whether the macrosomia and enhancement of fatty acid (FA) synthesis and/or content persisted postnatally in this animal model. Fetal hyperinsulinemia was produced in Sprague-Dawley rats by injecting fetuses with 2 units of insulin at 20.5 days of gestation. Alternate pups in the same litter were injected with saline. Pups were delivered surgically at 22.5 days of gestation, were weighed daily and sacrificed on day 15. FA content and synthesis rates of liver and skeletal muscle were measured. We found: (1) At birth, insulin-treated pups were 12% heavier than saline littermates, (5.88 +/- 0.14 g v 5.26 +/- 0.14 g, P less than .01); and (2) The enhanced growth associated with prenatal insulin treatment persisted during the suckling period, ie, compared with saline-treated controls, insulin pups were 15.7% heavier at 15 days of age (P less than .01); growth velocity of insulin pups, beginning on day 3, significantly exceeded that of control pups (P less than .05). FA contents of liver and muscle in insulin pups, (62.6 +/- 5.7 mumol/g and 62.7 +/- 13.2 mumol/g) were significantly greater (P less than .05) than in saline littermates (45.1 +/- 5.6 mumol/g and 30.2 +/- 4.7 mumol/g, respectively). We conclude that.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1985

Nitrogen and mineral balance in preterm infants fed human milks or formula.

Growth as well as nitrogen, calcium, sodium, and potassium balances were evaluated in 16 preterm infants weighing less than 1,600 g at birth, who were fed either their mother's milk, donated mature human milk, or standard commercial formula. Birthweight, gestational age, age of balance, and energy and fluid intakes were similar between groups. There were no differences between groups in the rate of growth. The infants fed their mother's milk (obtained 11-30 days into lactation) demonstrated nutrient balance similar to infants fed mature human milk. Infants fed standard commercial formula demonstrated significantly greater intake and retention of calcium compared to either human milk group. Infants fed either their mother's milk or mature human milk demonstrated net nitrogen and calcium retention below estimates of fetal nitrogen and calcium accretion. Infants fed standard formula demonstrated retentions that more closely approach the fetal estimates. This study did not demonstrate an advantage to feeding premature infants their mother's milk when compared to the feeding of mature donor milk.

Birth Weight↗

PubMed1985

Effect of non-nutritive and nutritive suck on gastric emptying in premature infants.

Ten healthy preterm infants were studied to determine if non-nutritive and nutritive suck significantly altered gastric emptying patterns when compared with gavage feeding alone. We used a 10% dextrose meal with phenol red marker and a double sampling technique to determine gastric emptying at 10-min intervals over a 30-min test period. A crossover study design compared the effects of the three feeding methods in each infant. The gastric residual volumes expressed in milliliters per kilogram did not differ significantly when comparisons were made among groups at 10, 20, and 30 min following the test meal. Non-nutritive suck and nutritive suck and swallow of a liquid dextrose meal do not significantly improve gastric emptying in healthy preterm infants. The beneficial effects of non-nutritive and nutritive sucking on the nutritional status of preterm infants, demonstrated by others, are not related to improved gastric evacuation of feeds. Alternative explanations for these beneficial effects require further investigation.

Gastric Emptying↗

PubMed1985

Energy intake, norepinephrine excretion, and oxygen consumption in low birthweight infants.

Eleven healthy, appropriately grown low birthweight infants, ages 3-15 days and 28-33 weeks gestation, were the subjects of this study. Energy intake, urinary norepinephrine excretion, and metabolic rate as reflected in VO2 were examined concurrently. Energy intakes were recorded. Simultaneous collection of a timed urine for norepinephrine excretion and measurement of VO2 using indirect calorimetry were performed. A servo control device was used to maintain an abdominal skin temperature of 36.5 degrees C. The results demonstrated increases in energy intake, urinary norepinephrine, and VO2 with advancing postnatal age. Simple linear regression analysis revealed significant positive correlations between energy intake and VO2 (p less than 0.003), norepinephrine excretion and VO2 (p less than 0.003), postnatal age and VO2 (p less than 0.01), and postnatal age and energy intake (p less than 0.001). Multiple regression analysis revealed a strong positive correlation between urinary norepinephrine excretion and VO2, and energy intake and VO2. When postnatal age was added to the multiple linear regression analysis as a variable, energy intake was no longer strongly correlated with VO2. This implies postnatal age and energy intake are closely linked in this study, and further studies are needed to better define these relationships.

Birth Weight↗

PubMed1985

Correlation of the interpretation of fetal heart rate records with cord plasma erythropoietin levels.

On the basis that fetal levels of plasma erythropoietin (Ep) may reflect fetal oxygenation the primary purpose of the present study was to assess the relation between Ep measured in cord plasma at delivery and the intrapartum fetal heart rate (FHR) record. A scoring system for interpreting FHR recordings blindly was prospectively utilized in 41 selected human pregnancies during the 4 h immediately preceding birth. The correlation of the overall mean FHR score for each individual patient with cord plasma Ep was significant such that the highest Ep levels were observed in those infants with the most abnormal FHR scores. Furthermore, when the birthweights of the infants were adjusted for gestational age, sex, and birth order, birthweight centile was negatively correlated with cord plasma Ep. When both FHR score and birthweight were simultaneously correlated with cord plasma Ep using multiple regression, the combined effect of these two factors improved the association of either alone with both contributing approximately equally.

Birth Weight↗

PubMed1985

The effects of arterial glucose infusion above the celiac axis in the neonatal lamb.

Refractory hypoglycemia has been reported in an infant receiving glucose infusion via an umbilical artery catheter (UAC) above the celiac axis. To prove the hypothesis that hypoglycemia resulted from direct glucose infusion to the pancreas, 15 term spontaneously delivered lambs were infused with 5.3 +/- 0.1 mg X kg-1 min-1 of glucose via an arterial catheter. In 9 glucose was infused below the celiac, and the glucose production rate (GPR) was derived. After a recovery period, the study was repeated with glucose infused above the celiac. During glucose infusion above the celiac, the plasma glucose concentration was lower than when the infusion was given below the celiac (140 +/- 6 vs. 175 +/- 11 mg/dl, p less than 0.01). There was also a fall in the average GPR (3.7 +/- 0.5 vs. 5.5 +/- 0.8 mg X kg-1 min-1, p less than 0.05). In 6 lambs the study was performed in the reverse sequence (high then low infusion) and no differences were noted in the parameters measured. However, there was a marked heterogeneity in the paired GPR in these lambs. We conclude that direct glucose infusion above the celiac increases glucose delivery to the pancreas. This produces increased insulin delivery to the portal system resulting in suppressed GPR and reduction in plasma glucose concentration. These changes may account for refractory hypoglycemia in infants clinically when glucose is infused above the celiac through a UAC.

Animals↗

PubMed1985

The effect of blood volume expansion on gastrointestinal oxygenation in piglets.

Regional and total gastrointestinal (GI) blood flow, O2 delivery, O2 extraction, and O2 consumption were measured before and after acute blood volume expansion in 2-day-old piglets. Blood flow was measured with radionuclide-labeled microspheres. Sixty minutes after a rapid transfusion of age- and hematocrit-matched piglet donor blood, 51Cr-measured blood volume increased 19% while an increase in hematocrit suggested plasma transudation to the extravascular space had occurred in response to blood volume loading. Following transfusion, total GI blood flow and O2 delivery did not change, although O2 extraction decreased by 31 +/- 4%. O2 consumption by the GI tract decreased from 2.0 +/- 0.19 ml O2 X min-1 X 100 g-1 to 1.46 +/- 0.24 ml O2 X min-1 X 100 g-1 1 h after transfusion. Feeding was then accomplished via orogastric tube to determine if animals stressed by blood volume loading would increase GI O2 consumption in response to feeding. The postprandial increase in GI O2 consumption was similar to that previously reported in newborn piglets. Therefore, in the fasting state, acute blood volume loading disrupts GI O2 transport at the capillary level and decreases GI O2 consumption. However, animals subjected to blood volume loading appear capable of increasing GI O2 consumption after feeding.

Animals↗

PubMed1985

Effects of hypoxemia on gastrointestinal blood flow and gastric emptying in the newborn piglet.

The effects of severe hypoxemia on gastrointestinal (GI) blood flow and gastric emptying were studied in nine 2- to 4-day-old piglets which were mechanically ventilated while receiving nitrous oxide anesthesia. Each animal was studied during a control period of oxygenation (PaO2 91 +/- 8 torr), 35 min of hypoxemia (PaO2 29 +/- 1 torr), and a recovery period (PaO2 90 +/- 5 torr) (mean +/- SEM). During each study period, the animal received a 10% dextrose test meal with phenol red marker (22 ml/kg), gastric residual volumes were determined at 10-min intervals over 30-min study periods using a dye dilution double sampling technique, and GI blood flow (radionuclide-labeled microspheres), O2 delivery, O2 extraction, and O2 consumption were measured at the end of the 30-min period. Hypoxemia resulted in decreased blood flow to the following GI organs: stomach, jejunal and ileal mucosa-submucosa, and colon decreased 62, 31, and 35%, respectively (p less than 0.05). Jejunal and ileal muscularis blood flow remained unchanged. Oxygen delivery and consumption by GI tract decreased 79 and 58%, respectively; whereas oxygen extraction of GI tract increased 115%. Values returned toward baseline levels during the recovery period. The hypoxemic gastric emptying pattern showed significantly greater gastric residuals at 20 min compared to the 10-min value (p less than 0.05). This pattern was different than that observed during control and recovery periods. We conclude that severe hypoxemia results in decreased GI blood flow, tissue oxygenation, and an altered gastric emptying pattern. These observations may have clinical significance for feeding infants following an hypoxemic episode.

Animals↗

PubMed1985

Brain bilirubin deposition and brain blood flow during acute urea-induced hyperosmolality in newborn piglets.

Acute hyperosmolality-induced blood brain barrier breakdown has been demonstrated to increase the permeability of sucrose, which is similar in molecular weight to bilirubin, independently of changes in regional brain blood flow. We studied three groups of piglets given continuous bilirubin infusions to maintain serum bilirubin concentrations at approximately 8 mg/dl. Normal serum osmolality was maintained throughout the study in control animals. Two experimental groups were made hyperosmolar (330 and 375 mosmol/liter) with bolus urea infusions during the last hour of the study. Regional brain bilirubin concentrations were elevated in the 375 mosmol/liter hyperosmolal experimental group, but not in the 330 mosmol/liter group. Regional brain albumin concentrations also were increased over the control group in the 375 mosmol/liter animals. There were no differences in regional brain blood flows to account for the increases in brain bilirubin concentrations. Our results show that brain bilirubin deposition occurs following breakdown of the blood brain barrier by acute, severe hyperosmolality (375 mosmol/liter) and that the deposited bilirubin is derived from both bound and unbound fractions. The bilirubin deposition occurs independently of changes in regional brain blood flow; however, regional differences in the blood brain barrier permeability to albumin also occur.

Animals↗

PubMed1985

Renal metabolism in fetal and newborn sheep.

The substrate and oxygen uptake by some organs in intact developing animals has been described, however, the kidney has not been studied. To examine substrate and oxygen uptake by the kidney, we implanted polyvinyl catheters into the renal vein, descending aorta, inferior vena cava, and urinary bladder of 11 fetal sheep (120-125 days gestation) and eight newborn lambs (1 day postnatal). Four days after surgery, blood samples were obtained simultaneously from the renal vein, aorta, and inferior vena cava for determination of oxygen content and saturation, and glucose and lactate concentrations. Renal blood flow was determined by the radionuclide-labeled microsphere method in the fetal lambs and by measuring 14C-inulin clearance in the newborn lambs. The fetal and newborn kidneys consumed oxygen at rates of 123 +/- 16 and 785 +/- 79 mumol/min/100 g kidney weight (mean +/- SEM), respectively. The increase in oxygen consumption from the fetal to the newborn period was accompanied by an increase in oxygen extraction from 25-35%, a large increase in oxygen delivery from 418 +/- 38 to 2231 +/- 127 mumol/min/100 g, and marked increases in glomerular filtration rate and sodium reabsorption (measured in six additional fetal sheep and the eight newborn lambs). This suggests that the postnatal increase in renal tubular activity is associated with an increase in oxygen consumption. Lactate was taken up by both fetal and newborn kidneys, and in nine of the 11 fetuses and in four of the eight newborns, there was net glucose release from the kidney.

Animals↗

PubMed1985

The effects of brain blood flow on brain bilirubin deposition in newborn piglets.

Since kernicteric lesions are usually found in the subcortical regions of the brain and these areas also receive the highest blood flow during asphyxia and hypercapnia, we hypothesized that increases in brain bilirubin deposition may be related to increases in brain blood flow. Fourteen piglets underwent a 3-h infusion of bilirubin to maintain total serum bilirubin at approximately 8 mg/dl, during which time blood gases, hemodynamic variables, and brain blood flow were determined. After sacrificing the animals, regional brain bilirubin content was determined. Ten piglets underwent the same protocol; in addition, hypercapnia was induced during the last hour of study (PaCO2 approximately 70 mm Hg). The regional brain blood flow and bilirubin deposition were significantly increased over control values (p less than 0.05) following hypercapnia in the subcortical region and significantly so in the midbrain and cerebellum. In separate groups of control (n = 6) and hypercapnia (n = 6) piglets, 125I-labeled albumin was infused and demonstrated that hypercapnia was not associated with increased regional brain albumin content. We conclude that hypercapnia-induced augmentation in regional brain blood flow is associated with increased deposition brain blood flow is associated with increased deposition of unbound bilirubin. Although the causal relationship between these two observations has not been firmly established, the findings deserve future investigation to clarify the role of brain blood flow, brain bilirubin deposition, and the production of kernicterus in high risk infants.

Albumins↗

PubMed1985

Neonatal morbidities in infants of mothers with glucose intolerance in pregnancy.

Of 1839 pregnant women screened prospectively, 52 were identified to have glucose intolerance. Ten additional pregnant women identified as having glucose intolerance before the universal screening were also included in the study cohort. These 62 patients were followed in a perinatal high-risk clinic with weekly plasma glucose determinations. The patients were treated with diet and, in addition, 21 of 62 were treated with insulin therapeutically. By observational cohort design, the infants and a comparable number of matched controls were evaluated for evidence of neonatal morbidities and classified into percentile for birth weight. Compared with the control group, the operative mode of delivery, the mean birth weight, the birth-weight percentile, the male/female ratio, the frequency of low Apgar score (less than or equal to 6 at 1 min), and the number of infants with congenital anomalies were significantly higher in the infants born to the glucose-intolerant mothers. Although the mean maternal blood sugar was maintained within a reasonably euglycemic range, the usual neonatal morbidities were not eliminated entirely. Further understanding and management of glucose intolerance in pregnancy is necessary to further diminish or eliminate neonatal morbidities.

Apgar Score↗