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Biomedical subjects

W Oh

Publications and source records attributed to W Oh.

At least 145 records · Page 8Linked to original sources
PubMed1988

The effects of brain bilirubin deposition on auditory brain stem evoked responses in rats.

Auditory brain stem evoked responses (ABR) in newborn infants are altered by elevated serum bilirubin levels and may be used as an indicator of bilirubin toxicity. The hypothesis of our study was that hyperbilirubinemia may affect ABR's because of bilirubin deposition in the brain stem. We examined this hypothesis by studying 21 male adult rats divided into three groups: group A, control (n = 8); group B, low bilirubin (n = 6); and group C, high bilirubin (n = 7). Each experimental group was studied over 150 min. The control group received a buffer solution. The low bilirubin group received a low dose bilirubin bolus of 50 mg/kg followed by continuous infusion of 20 mg/kg/h. The high bilirubin group received a bolus of 100 mg/kg bilirubin followed by continuous infusion of 40 mg/kg/h. All groups received sulfisoxazole (50 mg/kg X 3) during the second hour of the study. Auditory evoked potentials were recorded at 0 and 150 min. At the end of the study, the brains were analyzed for bilirubin content. Bilirubin deposition in the 3 groups was 0.6 +/- 0.28 micrograms/g, 0.93 +/- 0.07 micrograms/g and 3.2 +/- 2.2 micrograms/g for the control, low bilirubin and high bilirubin groups, respectively. Bilirubin deposition in the brain was associated with a significant amplitude reduction of Wave I and III, but had no effect on absolute latencies and interpeak latencies. Very high brain bilirubin concentrations were associated with absence of Waves I and IV. Wave I was also significantly reduced in the low bilirubin group where there was slightly increased bilirubin deposition in the brain. We conclude that ABR changes in the form of wave amplitude reduction were associated with brain stem and cerebellum bilirubin deposition. We speculate that previously reported observations of abnormal ABR changes in hyperbilirubinemic newborn infants are associated with bilirubin deposition.

Animals↗
PubMed1988

Mother-infant feeding interaction in full-term small-for-gestational-age infants.

Maternal and infant behavior during feeding was assessed in 30 mother-infant dyads: 15 small-for-gestational-age (SGA) infants (birth weights below the 10th percentile) and 15 appropriate-for-gestational-age (AGA) infants (birth weights between the 25th and 90th percentiles). The groups were balanced for gestational age, sex, neonatal risk factors, and maternal age, parity, socioeconomic status, and race. Behaviors indicative of infant feeding difficulties were coded for mother and infant. The SGA mothers had higher frequencies of these behaviors than did their AGA counterparts. Qualitative ratings of interactive behavior were recorded for mother and infant: SGA infants had ratings indicative of less optimal interactions than those of the AGA group. Infant caloric intake (calories per kilogram per feeding) was calculated by first dividing the change in infant weight in grams before feeding and immediately after feeding by the infant's weight before feeding and then converting it to calories. Although no difference in caloric intake was observed between the two groups, infant behaviors and ratings were associated with caloric intake. These data suggest the importance of including neonatal behavior during feeding in the risk assessment of potential growth failure in SGA infants.

Bottle Feeding↗
PubMed1988

Ontogeny of glucose homeostasis in low birth weight infants.

Suppression of the endogenous glucose production rate (Ra) is the adult response to glucose infusion. Persistent Ra (greater than or equal to 1 mg.kg-1min-1 or less than 80% decrease in basal Ra) in response to glucose infusion is evidence of a transitional homeostatic state in the neonate during the first days after birth. To determine whether postnatal development produces an adultlike response, Ra was measured in 11 infants (birth weight 1716 +/- 48 g, gestational age 33 +/- 0.3 weeks) at 2 to 5 weeks of age. In these paired studies, 4 micrograms.kg-1min-1 D-(U-13C)glucose tracer was infused by prime constant infusion to determine Ra, during infusion of either saline solution or glucose, the latter at a rate of 5.3 +/- 0.2 mg.kg-1min-1 (mean +/- SEM). When the results of the saline infusion turnover period were compared with those of the glucose infusion turnover period, plasma glucose concentration increased significantly, from 88 +/- 3 mg/dL to 101 +/- 4 mg/dL (P less than 0.001). Plasma insulin concentration remained unchanged (12 +/- 5 microU/mL vs 8 +/- 3 microU/mL). Ra was heterogenous during glucose infusion, and persistent Ra was present in six of 11 infants. Of the five infants who had decreased Ra during glucose infusion, three received glucose at a rate exceeding basal Ra. Of the remaining six infants who evidenced persistent Ra during glucose infusion, three received glucose at a rate equal to or in excess of basal Ra. We conclude that glucose homeostasis in low birth weight infants is transitional throughout the neonatal period.

Age Factors↗
PubMed1988

Language development of low-birthweight infants at two years.

Fifty low-birthweight (LBW) and 18 fullterm normal infants were prospectively evaluated at eight months and two years of age for language development and neurodevelopmental status. The LBW cohort was divided into those who were appropriate for gestational age (AGA) (N = 35) and small for gestational age (SGA) (N = 15) to assess the effect of intra-uterine growth retardation on language development within a premature population. LBW SGA infants lagged significantly behind term infants in both receptive and expressive language, but to a lesser degree than LBW AGA infants. Multiple regression analyses of gestational age, Hollingshead socio-economic status score, and eight-month neurological score as independent variables, and the receptive and expressive language scores as dependent variables, indicated that these three predictor variables had a significant cumulative effect on language development. Language was delayed in 28 per cent of the LBW children at two years.

Brain Diseases↗
PubMed1988

Renal function and fluid therapy in high risk infants.

In recent years, the survival rate of high risk infants has markedly increased. The role of such medical management as fluid, electrolyte and nutritional therapy have assumed a greater importance in assuring optimal quality of the survivors. The very low birth weight infants, particularly those with respiratory distress syndrome and perinatal asphyxia, are at highest risk. The inefficient renal function, unique characteristic of body fluid composition and/or presence of severe clinical illness often make the management of fluid and electrolytes in this group of infants difficult. The numerous factors that influence insensible water loss make calculation of fluid management in the high risk infant even more challenging. Systematic collection of data such as daily body weight, intake, output, urine specific gravity and serum electrolyte is essential to appropriately maintain fluid and electrolytes balance in these infants. Respiratory distress syndrome is a common problem in premature infants and the fluid and electrolyte management in these infants will require similar attention to details as described for the fluid and electrolytes of very low birth infants. Perinatal asphyxia often results in oliguria or anuria because of possible development of inappropriate ADH secretion or acute tubular necrosis. It is essential that fluid restriction be done on the first day or two of life to avoid fluid overload.

Asphyxia Neonatorum↗
PubMed1988

Cerebral cortical blood flow and oxygen metabolism in normocythemic hyperviscous newborn piglets.

Our study tests the hypothesis that hyperviscosity independent of arterial O2 content reduces cerebral cortical blood flow, O2 delivery, and O2 uptake. After baseline determinations, ten 2- to 4-day-old awake spontaneously breathing piglets were given an intravenous infusion (5 ml.kg-1, body weight) of concentrated cryoprecipitate, whereas eight controls received normal saline. Cerebral cortical blood flow, arterial and superior sagittal sinus O2 content, whole blood viscosity, hematocrit, blood gases, and plasma fibrinogen concentrations were measured at baseline and 3 h after infusion. No significant changes were observed in the control group. Three hours after the infusion of concentrated cryoprecipitate the experimental group showed an increase in whole blood viscosity, whereas hematocrit and arterial O2 content were unchanged. There was a decrease in cerebral cortical blood flow and cerebral cortical O2 delivery, whereas cerebral cortical O2 uptake was unchanged. We conclude that hyperviscosity independent of arterial O2 content reduces cerebral cortical blood flow and that although O2 delivery was reduced in the newborn piglet cerebral cortical O2 uptake was maintained.

Animals↗
PubMed1988

Behavioral responsiveness in preterm infants with intraventricular hemorrhage.

Preterm infants with varying degrees of intraventricular hemorrhage (none, n = 21; grade I to II, n = 22; grade II to IV, n = 24) and a group of full-term infants (n = 21) were compared with regard to behavioral responsiveness and parental reports of the infant's temperament. Behavioral responsiveness was assessed during the presentation of 15 visual, auditory, and tactile stimuli at 3 months of age (corrected age for preterm infants). Summary scores for positive and negative responsiveness, as well as sociability, soothability, and overall activity levels, were derived from behavioral observations by coders who were unaware of the infant's characteristics. The Bates Infant Characteristic Questionnaire was completed by the main care giver and scored on four summary variables: fussy-difficult, unadaptable, dull, and unpredictable. Preterm infants, regardless of the presence or severity of intraventricular hemorrhage, showed less positive responses and less overall activity in response to stimulation. Infants with grade I to II intraventricular hemorrhage were less sociable and more difficult to soothe than full-term control infants. Individual differences in positive, negative, sociability, and soothability were related to the questionnaire scores of fussy-difficult and unadaptability. Both prematurity and degree of intraventricular hemorrhage affect behavioral responsiveness and these individual differences are related to parental reports of the infant's temperament.

Affect↗
PubMed1987

Growth and cellular composition in rats with intrauterine growth retardation: effects of postnatal nutrition.

We evaluated the catch-up growth of rats with intrauterine growth retardation (IUGR) raised in normal litters (8-10 pups) or in large litters (14-16 pups) during the first 2 wk of life. We also studied the influence of nutrition on cellular composition at birth and at 2 wk. Fifty-four pups (27 IUGR and 27 controls) were enrolled into normal or undernutrition groups. Postnatal undernutrition resulted in significantly lower growth in both control and IUGR rat pups than in normally fed pups. In the control group, postnatal undernutrition resulted in a lower liver weight but not a lower brain weight. Underfeeding of the IUGR group produced a greater number of cells of the brain and liver, but with smaller cell size than in normally fed IUGR rats. We conclude that compensatory catch-up growth in the mild-IUGR rat occurs if the postnatal nutrition is adequate. When postnatal nutrition is restricted, the non-IUGR rats became malnourished at 2 wk of age and the mild-IUGR rats did not demonstrate the catch-up growth phenomenon as was seen in those with adequate nutrition. In the severe-IUGR rat, undernutrition further compromised growth rate, so that at 2 wk of age their weights were the lowest of all the groups studied.

Animal Nutritional Physiological Phenomena↗
PubMed1987

Prolonged hypercarbia in the awake newborn piglet: effect on brain blood flow and cardiac output.

In adults, exposure to prolonged hypercarbia results in a normalization of the extravascular brain pH associated with a reduction in brain blood flow (BBF). Following prolonged hypercarbia, sudden normalization of the arterial PCO2 also produces a change in the extravascular brain pH to an alkaline state, resulting in a marked decrease in BBF. We examined these physiologic phenomena in newborn subjects by exposing seven awake, spontaneously breathing newborn piglets to 4 h of sustained hypercarbia (PaCO2: 60-70 mm Hg) followed by a 45-min normocarbic period. Total and regional BBF, cardiac output (radionuclide-labeled microsphere method), arterial blood pressure, plasma catecholamine and lactate concentrations, blood gases, oxygen contents, and hematocrits were measured during a baseline period, at 1/2, 2, and 4 h of sustained hypercarbia and 1/4 and 3/4 h following an abrupt onset of normocarbia. The initial 2.5-fold increase in total BBF during hypercarbia persisted for 2 h and at 4 h decreased significantly below the level of the 30-min hypercarbic measurement, although the values still remained 2-fold above the baseline values. Brain tissue pH was reduced at the onset of hypercarbia, remaining unchanged throughout the hypercarbic period. Both total BBF and brain tissue pH returned to baseline values following the return to normocarbia. Changes in regional BBF were similar to that of total BBF with the exception of the boundary zone (periventricular area in the frontoparietal region of the cerebrum, adjacent to the caudate nucleus) and the parietal area (site of the brain tissue pH electrode), where a significant decrease from the peak hyperemia was not observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Accelerated growth and abnormal glucose tolerance in young female rats exposed to fetal hyperinsulinemia.

This study was designed to evaluate the relationship between fetal macrosomia and postnatal growth as well as the glucose homeostasis in young female rats. We produced fetal macrosomia by fetal insulin injection at 20 1/2 days of gestation. The control subjects were injected with saline. The weights were recorded weekly from birth up to 12 wk. Only the female rats were studied. At 4, 6, 10, and 12 wk of age, oral glucose tolerance tests were performed. Also, at wk 6, 10, and 12, peri-renal-ovarian-salpingeal fat weights, the RNA, DNA, and protein contents of the abdominal muscle were determined. One-hundred seventeen control and 78 macrosomic rats were studied. The macrosomic rats showed a higher body weight (10-12%) than the control rats from birth up to 8 wk, but at 10 and 12 wk their weights were similar. The fat weights reflected the body weights, i.e. a higher fat weight in the macrosomic rats during the period of accelerated growth (from birth up to 8 wk), and a similar fat weight when the body weight of the two groups were similar at 10 and 12 wk. At 4 and 6 wk of age, the plasma glucose level measured in response to the oral glucose loading were similar in both groups. However, at 10 and 12 wk of age, the macrosomic rats had significantly higher fasting plasma glucose levels and exhibited consistently higher plasma glucose levels for the 3.5-h period of postglucose administration compared to the control rats. The plasma insulin levels rose significantly following glucose challenge. However, the values were similar in both groups at 10 and 12 wk.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Postprandial gastrointestinal blood flow and oxygen consumption: effects of hypoxemia in neonatal piglets.

The effects of feeding on gastrointestinal (GI) perfusion and oxygen transport in hypoxemic neonates is unknown. We evaluated these effects in unanesthetized, spontaneously breathing newborn piglets by comparing three experimental groups: nine hypoxemic piglets (mean PaO2 26 torr) which were fed with formula, six hypoxemic piglets (mean PaO2 27 torr) which were not fed, and four normoxemic piglets (mean PaO2 79 torr) which were fed and served as controls. The control-fed group exhibited an increase in stomach and small intestinal mucosal-submucosal blood flow within 30 min following feeding which was significantly greater than that observed in the hypoxemic fed piglets. GI O2 delivery and O2 uptake rose significantly (p less than 0.05) following a meal secondary to increases in total GI blood flow. Oxygen extraction was unchanged postprandially in the control group. In the hypoxemic nonfed piglets, total and regional GI blood flow was unaltered during hypoxemia. Reductions in arterial O2 content led to significant decreases in GI O2 delivery. Gastrointestinal oxygen uptake remained stable with a compensatory increase in GI O2 extraction. In the hypoxemic-fed piglets, hypoxia significantly decreased stomach blood flow and led to unchanged blood flow in the remainder of the GI tract. Significant reductions in arterial O2 content and GI O2 delivery were observed, accompanied by significant increases in O2 extraction. Hypoxemic fed animals did not exhibit the expected increase in O2 uptake to meet postprandial metabolic demands. When the hypoxemic insult was terminated, fed piglets demonstrated significant total and regional GI hyperemia leading to increased GI O2 uptake when compared with hypoxemic nonfed piglets.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Anemia blunts the thermogenic response to environmental cold stress in newborn piglets.

We tested the hypothesis that isovolemic anemia blunts the thermogenic response to environmental cold stress in 3 to 4-day-old newborn piglets. Eight animals were studied in both thermoneutral (31.6-32.8 degrees C) and cold (19.6-20.2 degrees C) environments, before and after an isovolemic, partial volume exchange transfusion which reduced the hematocrit from 26 to 15%. In the nonanemic phase of study, deep rectal temperatures declined but had plateaued by 30 minutes after onset of cold stress and remained within normal limits for newborn piglets. In the anemic phase of study, deep rectal temperature declined continuously throughout cold stress with true body core hypothermia (less than 38 degrees C) observed at all measurement points beyond 15 min of cold stress. Baseline oxygen consumption did not differ between the two study phases (17.6 +/- 1.8 versus 16.7 +/- 2.1 ml/kg-1/min-1, mean +/- SEM). However, during environmental cold stress, oxygen consumption increased by 64% over baseline in the nonanemic phase of study (p less than 0.05) whereas 21% increase over baseline was observed in the anemic phase (p NS). We conclude that isovolemic anemia limited oxygen consumption and heat production during environmental cold stress, resulting in body core hypothermia.

Anemia↗
PubMed1987

The in vivo effect of bilirubin and sulfisoxazole on cerebral oxygen, glucose, and lactate metabolism in newborn piglets.

Bilirubin inhibits in vitro oxidative phosphorylation and glycolysis. This study investigated the in vivo effect of bilirubin on cerebral oxygen, glucose, and lactate uptake in newborn piglets. Seventeen 2- to 4-day-old piglets were divided into three groups and examined as follows: group 1 = control (C); group 2 = control with sulfisoxazole; and group 3 = experimental, given bilirubin with sulfisoxazole. In the experimental group, bilirubin was infused for 4 h. The cerebral bilirubin content in the bilirubin-infused group was 11.0 +/- 1.4 nmol/g of cerebral cortex (mean +/- SEM), consistent with levels found in infants with kernicterus. However, this level of brain bilirubin had no major, acute effects on cerebral uptake of oxygen, glucose, or lactate despite producing lethargy and ataxia which were consistent with bilirubin intoxication. This suggests that mitochondrial changes may not be involved in vivo in acute bilirubin encephalopathy.

Animals↗
PubMed1987

The social ecology and early parenting of Caucasian adolescent mothers.

Social characteristics, maternal behaviors, and the home environments of Caucasian adolescent and nonadolescent mothers were investigated in a sample of 50 primiparous low- and middle-class women and their 4-month-old infants. The mothers were interviewed about their child-care network and about stressful life events that may have occurred since the infant's birth. The HOME inventory was completed and videotapes of 2 hours of home observations were coded to assess maternal proximity, verbalizations, activity, and physical contact with the infant. Interview data indicated that adolescent mothers relied more frequently on other teenagers and other network members for help in child care than nonadolescent mothers. In addition, they also received more frequent support from their mothers and less frequent help from their partner's and partner's mother and siblings than nonadolescent mothers. During the home visit, they were less verbal with their infants and scored significantly lower on the Responsiveness and Maternal Involvement subscales as well as on the total HOME inventory; these results were replicated on subgroups matched for socioeconomic status, emphasizing the unique social context and parenting practices of teenage mothers.

Adolescent↗
PubMed1986

Should the fifty-gram, one-hour plasma glucose screening test for gestational diabetes be administered in the fasting or fed state?

To determine whether the 50 gm, 1-hour plasma glucose screening test for gestational diabetes should be administered in the fasted or fed state, 50 presumed normal and 20 gestational diabetic pregnant women in the early third trimester underwent this test twice, once under each condition, within a 1-week interval. There was no difference in test results under the two conditions among the normal individuals (fasted 118.4 +/- 24.7 mg/dl; fed 115.8 +/- 23.4 mg/dl). However, when the test was administered to women with known gestational diabetes, the result was significantly (p = 0.011) higher if patients were fasted (173.9 +/- 28.8 mg/dl) than if they had been given a standard 600 kcal meal 1 hour previously (154.8 +/- 24.1 mg/dl). The effect of these two conditions on the sensitivity and specificity of the screening test is described, and it is suggested that the threshold for glucose tolerance testing be 130 mg/dl if the test is administered in the fed state.

Adult↗
PubMed1986

Effects of maternal transport on admission patterns at a tertiary care center.

Major changes have occurred in the delivery of perinatal care during the last two decades. Documentation of perinatal regionalization statistics at Women and Infants Hospital of Rhode Island in Providence support the increasing proportion of low birth weight infants in the region being born at the tertiary care center, the decreasing number of neonatal transports in concert with an increasing number of maternal transports, and the increasing proportion of neonatal transports with birth weights greater than or equal to 2500 gm. Patterns of modern perinatal care are materially changing the delivery of health care at tertiary care facilities.

Birth Weight↗
PubMed1986

Effect of respiratory acidosis on glucose homeostasis in experimental intrauterine growth retardation in rats.

Hypoglycemia and asphyxia account for a significant proportion of morbidity in the infant with intrauterine growth retardation (IUGR). The purpose of this study was to evaluate changes in glucose homeostasis in IUGR rats during acute respiratory acidosis. IUGR was produced by bilateral uterine artery ligation at 17 days of gestation in 14 pregnant rats with 23 successfully delivered pups. The normal pups (n = 31) were those whose mothers were sham operated at the same gestational period. The IUGR and normal pups were studied at 2 days of age. One group of pups was studied under room air while another was subjected to 20 min of exposure to a gas mixture of 10% O2/15% CO2, balanced with N2. Gluconeogenesis in the liver and carcass, as well as plasma glucose and catecholamines were determined before and after the exposure to the gas mixture. The results showed that the 2-day-old IUGR rats have lower body weight (P less than 0.001), liver weight (P less than 0.001), plasma glucose (P less than 0.001), and rate of gluconeogenesis (P less than 0.01) when compared with the normally grown rats. During respiratory acidosis, the normally grown rats showed an increase in plasma epinephrine (P less than 0.005) without significant change in plasma glucose and rate of gluconeogenesis. The IUGR rats on the other hand, demonstrated a decrease in rate of gluconeogenesis (P less than 0.02), an increase in plasma glucose (P less than 0.001) while the plasma epinephrine level remained unchanged. We speculate that respiratory acidosis blunted cellular metabolism in the IUGR rat resulting in decreased peripheral glucose utilization.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidosis, Respiratory↗