Polycythemia in the newborn infant.
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Blood Viscosity↗
Biomedical subjects
J A Lemons
Publications and source records attributed to J A Lemons.
Vitamin E--how much is too much?
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Adult↗
Congenital lobar emphysema due to a bronchogenic cyst.
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Adult↗
Fetal and maternal amino acid concentrations during fasting in the ewe.
The present investigation was undertaken to quantitate the whole-blood amino acid concentrations of the mother and fetus over an extended period of fasting using a chronic sheep preparation. Fetal amino acid levels generally increased or remained relatively high during the fast (e.g., alanine, glycine, valine, leucine). In contrast to the situation in the fetus, most amino acids (alanine, glycine, glutamine, serine, and threonine) decreased in concentration in the ewe with fasting. Alanine levels changed most dramatically in the ewe, decreasing to less than 50% of the fed state values within 72 h of fasting. Therefore, while the supply of gluconeogenic amino acids becomes limited within the maternal circulation during fasting, levels of these amino acids remain high or increase in the fetal arterial blood.
Alanine↗
Changes in ovine fetal hindlimb amino acid metabolism during maternal fasting.
The flux of various substrates across the ovine fetal and maternal hindlimbs was measured in the fed state and after 5 days of maternal fasting. Whole blood concentrations of glucose, oxygen, ammonia, and six amino acids (glutamate, glutamine, alanine, valine, isoleucine, and leucine) were determined in the fetal and maternal femoral artery and distal inferior vena cava in 15 chronic animal preparations. During fasting the fetal arterial glucose concentration fell by 40% (from 0.828 to 0.494 mM), and the arteriovenous concentration difference decreased by 30% (from 0.148 to 0.099 mM). Similar changes were noted in maternal blood. Fetal oxygen concentrations remained similar between the fed and fasted state, and the fetal arteriovenous oxygen concentration difference increased slightly from 0.861 to 1.02 mM. The glucose oxygen quotient decreased in the fetus from 1.20 to 0.621. In addition, significant changes occurred in the net balance of several amino acids during the fasted state. Both alanine and glutamine, which demonstrated a positive uptake by the fetal hindlimb during the fed state, showed a substantial efflux from the fetal hindlimb during the fasting period. The fetal arteriovenous concentration difference of the branched-chain amino acids (leucine, isoleucine, and valine) increased significantly during fasting. These observations are consistent with the hypothesis that the ovine fetus adapts to a diminished supply of glucose from the mother by enhanced amino acid catabolism and, possibly, proteolysis with subsequent release of gluconeogenic precursors in the form of alanine and glutamine.
Amino Acids↗
Metabolic balance of the ovine fetus during the fed and fasted states.
The present study was performed in order to quantitate the uptake and excretion of a number of metabolic substrates by the sheep uterus as well as the fetus during the fed and fasted states within the same animals. 5 dated Suffolk sheep were studied initially at least 7 days after surgical placement of catheters in the fetal umbilical artery and vein, as well as the uterine veins and maternal artery. During the fed state and after 5 days of complete maternal fasting, measurements were made of uterine and umbilical blood flow by the steady-state antipyrine method, and the concentrations of whole blood glucose, oxygen, ammonia, 23 amino acids and plasma urea nitrogen were assessed. The results indicate that free amino acids and glucose comprise the major substrates required by the fetal lamb during both the fed and fasted states. While a number of amino acids changed in concentration in both the maternal and fetal circulations, few amino acids demonstrated a significant change in uptake in either the umbilical or uterine circulations. Similarly, no changes were observed in the uptake of oxygen by either the fetus or the uterus, while glucose consumption by the fetus decreased substantially with a concomitant increase in urea production. Consumption of both glucose and oxygen by the uteroplacenta remained unchanged during fasting. Leucine is one of several amino acids which is metabolized to a significant extent within the uteroplacenta, and theoretically may play a role in modulating glucose metabolism within the placenta and fetus.
Amino Acids↗
Incidence of retinopathy of prematurity in a tertiary newborn intensive care unit.
This study determined the incidence of retinopathy of prematurity (ROP) in 2,958 admissions to the Newborn Intensive Care Unit of the James Whitcomb Riley Hospital for Children, Indianapolis, between January 1976 and December 1979. Among 2,484 survivors, acute ROP developed in 72 (2.9%); 60 (83%) of these newborns had birth weights of less than 1,500 g. The incidence of acute ROP among survivors with birth weights of less than 1,000 g (28%) was approximately three times that of the survivors with birth weights between 1,001 and 1,500 g (10.1%). The overall incidence of blindness was 4.5% of surviving infants less than 1,000 g and 1.2% of those surviving with birth weights of 1,000 to 1,500 g. Evidence of the strong influence of immaturity and low birth weight on the risk of development of ROP is reaffirmed. Increasing survival of the most susceptible infants may be the factor contributing most to the overall incidence of ROP.
Birth Weight↗
Amino acid composition of preterm and term breast milk during early lactation.
The amino acid composition of the protein nitrogen (PN) and non-protein nitrogen (NPN) fractions of human milk obtained from mothers delivering maturely and at term was studied weekly until 44 weeks postconceptual age. Preterm milk contained significantly more total nitrogen (TN) and PN than the term milk; the NPN component was similar between the two groups. The amount of PN decreased significantly in both term and preterm milk during the first weeks of lactation (from approximately 300 mg/100 ml at day 7 to approximately 220 mg/100 ml at 8 weeks), while the level of NPN remained constant (approximately 33 mg/100 ml). The concentrations of almost all amino acids in the PN fraction also decreased during early lactation, while those in the NPN portion remained relatively constant. Glutamate (1630 microM) and taurine (398 microM) were the most plentiful amino acids found in the NPN fraction. No differences in the amino acid composition of the PN were detectable between the preterm and term group. Amino acids measured in this study accounted for 67% of the TN present. Whether the remaining 33% of the nitrogen can be attributed to nitrogen-containing substances other than amino acids and/or methodologic error is not known.
Amino Acids↗
Bacterial growth in human milk during continuous feeding.
The present study was undertaken to determine both the time at which exponential growth of bacteria ensued in human milk during a continuous feeding and whether the fat content of the milk changed during a continuous feeding. Breast milk samples were obtained from 19 healthy lactating women between the 7th and 28th postpartum day. Nine samples were refrigerated and utilized in a simulated continuous feeding within 24 hours of collection. The remaining 10 samples were frozen for four to six weeks until use in the simulated feeding study. Bacterial colony counts and fat content (by creamatocrit) were then measured at the beginning of the simulated feeding and at hourly intervals from five to eight hours after the initiation of the study. Results indicated that logarithmic growth of the contaminating bacteria was not observed during the study time. No significant increase in total colony count was observed over the course of study in the frozen milk samples, whereas a significantly increased colony count was apparent by six hours for the fresh milk samples. Fat content of the milk decreased significantly within six hours for the frozen samples and within eight hours for the fresh milk. These data would suggest that when continuous drip feeding methods are employed for providing human milk to newborn infants, it may be desirable to change the entire feeding apparatus (syringe, tubing, and milk) at four hour intervals in order to optimize caloric intake and minimize the risk of bacterial overgrowth.
Bacteria↗
Amino acid metabolism in the ovine fetus.
Quantitative measurements of the umbilical uptake of a variety of substrates were made in the ovine fetus in both the fed state and after 5 days of maternal fasting. Blood flow was measured in both study periods using the antipyrine method, with the simultaneous measurement of umbilical vein and arterial concentrations of glucose, oxygen, and 25 amino acids in whole blood. Umbilical blood flow and fetal oxygen consumption remained unchanged between the fed and fasted states. Umbilical glucose uptake decreased from a mean of 6.85 to 2.79 mg X kg-1 X min-1 with a concomitant fall in the glucose:oxygen quotient from a mean of 0.70 to 0.31. Whereas the majority of gluconeogenic amino acids decreased in concentration in the maternal circulation during fasting, the branched-chain amino acids, as well as 3-methylhistidine, increased. In contrast the majority of amino acids in the fetal arterial circulation either increased significantly or remained unchanged in concentration. Although the fetal excretion of urea increased by 70% during the period of maternal fasting, the total fetal uptake of nitrogen in the form of free amino acids via the umbilical circulation did not change (1,337 vs. 1,027 mg X kg-1 X day-1). These data suggest that the supply of amino acids from the mother to the fetus does not change dramatically during maternal fasting. Therefore, the fetus must either catabolize amino acids previously destined for fetal tissue synthesis and/or begin catabolizing its own protein stores.
Amino Acids↗
Developmental outcome of very low birth weight infants requiring a ventriculo-peritoneal shunt.
All infants of less than 1,500 g birth weight who required a ventriculo-peritoneal shunt were followed for developmental problems over the 1st year of life. There were 19 infants; 2 died within the 1st postoperative week. At 1 year of age corrected for prematurity the mean Bayley Mental Developmental Index was 62 +/- 23.0, and the mean Psychomotor Developmental Index was 61 +/- 19. Only 2 infants attained scores greater than 85 on both scales, while an additional 2 infants attained a score of greater than 85 on one scale. It is concluded that ventriculo-peritoneal shunting procedures performed after progressive ventricular enlargement has taken place are not likely to result in normal development of the infant less than 1,500 g birth weight.
Cerebrospinal Fluid Shunts↗
The effect of amniotic fluid aspiration on pulmonary function in the adult and newborn rabbit.
Aspiration of uncontaminated human amniotic fluid was investigated in adult and newborn rabbits and compared with three other experimental groups: 10% meconium solution, saline, and sham-injected controls. Fluids were injected into the trachea of adult animals (4 or 6 ml/kg body weight), newborn vaginally-delivered animals (a mean volume of 8 ml/kg), and cesarean-delivered animals before their first breath (a mean volume of 11 ml/kg). In adult animals aspirating amniotic fluid or saline, arterial PO2 measured over a 24-h period showed a mean difference between groups of less than 5% for both 4 and 6 ml/kg. Meconium aspiration produced a greater depression in PO2 than amniotic fluid aspiration (a mean difference of 16 and 31% for 4 and 6 ml/kg, respectively) and animals aspirating meconium showed a deteriorating trend over 24 h, whereas animals aspirating amniotic fluid improved. One of eight adult animals aspirating amniotic fluid died versus four of five aspirating meconium. All five animals aspirating saline 6 ml/kg survived. Lung weight and resting volume of adult animals aspirating amniotic fluid were not significantly different from animals aspirating saline or nothing. Lung pressure volume curves from adult animals aspirating amniotic fluid were nearly identical to controls. Histology showed significantly greater atelectasis in adult animals that received 6 ml/kg amniotic fluid than controls, but this was not different from saline. There was no association between the number of cells in amniotic fluid and arterial PO2 after aspiration or any other aspect of pulmonary function measured.(ABSTRACT TRUNCATED AT 250 WORDS)
Amniotic Fluid↗
Feeding practices of the very low-birth-weight infant within the first year.
Information summarized from early feeding practices of VLBW infants (1,500 gm. or less at birth) identified three prevalent practices which potentially could result in compromised nutrition for these babies: (1) Cereals were introduced at an early age. Feeding cereals before infants are developmentally ready may decrease formula intake or result in a forced feeding situation. (b) Two percent and skim milk were fed to approximately 50% of these infants within their first year of life. Feeding calorically dilute milk may reduce energy intake, as well as compromise the intake of essential fatty acids. (c) Whole cow's milk was introduced to some VLBW infants at an early age. The feeding of cow's milk to young infants without appropriate supplementation may predispose these infants to significant nutritional deficiencies and imbalances. Any one of these feeding practices could affect an infant's nutrient intake. If all three are encountered in the same baby, growth may be adversely affected. Whether increased attention to appropriate feeding practices during the first year of life would result in a more favorable growth outcome for VLBW infants is not known.
Adolescent↗
Growth outcome of the very low-birth-weight infant at one year.
Growth patterns of weight, length, and OFC complete through 12 months corrected age were determined for 122 VLBW infants who weighed 1,500 gm. or less and were 35 weeks or less gestational age at birth. Significant differences in growth were apparent when infants were grouped according to sex and appropriateness of intrauterine growth. When the mean values of each group were compared, the female AGA infants demonstrated growth at higher percentiles (NCHS term infant norms) for all three growth parameters (weight, length, and OFC). AGA male, SGA male, and SGA female infants all grew similarly, at lower percentiles for weight and length, when compared with the same norms. Growth in OFC was closest to term infant norms in all subgroups of infants. (formula; see text) Appropriateness of weight for length was determined for each of the infants at one year corrected age. The majority of the babies, regardless of subgroup, achieved weights and lengths greater than the 5th percentile and with normal weights for lengths. At 12 months corrected age, 30% remained below the 5th percentile in weight, 21% below the 5th percentile in length, and 14% below the 5th percentile in OFC. Eighteen infants (15%) demonstrated a disproportionately low weight for length (less than the 5th percentile).
Adolescent↗
Osmolality of substances used in the intensive care nursery.
It has been well documented that the administration of hypertonic substances to the newborn may result in a variety of adverse effects, including hepatic, intestinal, and/or neuronal injury. Furthermore, neonates are exposed to a large number of drugs and other substances while in the intensive care nursery setting. As few data are available that document the actual osmolality of many of the substances employed in caring for the sick neonate, the present study measured the osmolality of 64 medications as well as 23 formulas or nutritional supplements used in the intensive care nursery. Osmolality was determined by both vapor pressure and freezing point depression. Results indicate that a large number of medications normally administered by the enteral route possess a markedly elevated osmolality in excess of 2,000 mosm/kg H2O. Although parenterally administered medications normally have a much lower osmolality, several possess significantly elevated levels. It is recommended that measures be taken to minimize the osmolality of substances administered to the critically ill newborn whenever possible.
Anti-Bacterial Agents↗
Respiratory distress following elective repeat cesarean section.
The clinical course and chest radiographs of 47 infants with respiratory distress after elective cesarean section were reviewed. The mean difference between the gestational age determined prenatally and that postnatally was 2.6 +/- 1.6 weeks. However, 14 of the infants were delivered at term. All 47 infants required more than 40% oxygen, and 18 infants required a respirator. Fifteen infants developed a pneumothorax; one, a pneumopericardium; one, bronchopulmonary dysplasia; and one infant died. Chest radiographs and the clinical course were consistent with hyaline membrane disease in 17 patients; respiratory distress syndrome type II in 24; and in three the radiographic findings were normal. These data suggest that some of the respiratory morbidity subsequent to elective repeat cesarean section is not secondary to iatrogenic delivery of a premature infant, and that much of it is not due to hyaline membrane disease. These data emphasize that respiratory distress in an infant delivered by elective cesarean section does not necessarily suggest poor prenatal care in regard to the timing of delivery.
Cesarean Section↗
Lack of lactobezoars in infants given predominantly whey protein formulas.
Lactobezoars have been reported with increasing frequency in low-birth-weight infants. The etiology of a lactobezoar is not well understood and is probably multifactorial. During a 2 1/2-year period, 29 of 442 infants weighing less than 2,000 g who were fed casein-predominant formulas had lactobezoars. During the subsequent 14-month period, 223 infants weighing less than 2,000 g were fed a whey-predominant formula, and none had lactobazoars. There have been no reports of lactobezoars in infants fed human milk or whey-predominant formulas. It would appear that the presence of casein as the predominant protein is necessary for the development of a lactobezoar.
Bezoars↗
Normal gallbladder appearing as abdominal mass in neonates.
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Abdomen↗