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Biomedical subjects

J A Lemons

Publications and source records attributed to J A Lemons.

At least 55 records · Page 3Linked to original sources
PubMed1987

Hearing screening of high risk newborns.

Prospective screening of an extremely high risk group of 137 infants cared for in the Newborn Intensive Care Unit of the James Whitcomb Riley Hospital for Children was undertaken during 1983. Auditory brain stem responses (ABR) were obtained utilizing a clinical evoked potential system (Madsen 2250). Patients were selected for screening prior to discharge or transfer to the referring hospital on the basis of one or more of the following criteria: birth weight less than 1250 grams; birth weight less than 1500 grams and ventilatory support; significant depression at birth (Apgars less than 3 and 6 at 1 and 5 minutes, respectively); seizures, meningitis, and/or sepsis. Of the original 137 infants tested, 82 passed the initial ABR, 22 conditionally passed, and 34 failed. Eighty-two infants had follow-up behavioral and audiometric testing while 20 infants died and 35 were lost to follow-up. Four infants had severe sensorineural hearing loss, each of whom had failed the initial ABR. None of the infants who initially passed or conditionally passed the ABR had sensorineural hearing loss on follow-up testing. High risk factors for sensorineural hearing loss in the neonatal period included: intraventricular/periventricular hemorrhage, apnea, family history, major malformations of the head and neck, and possibly hyperbilirubinemia and congenital infection. No relationship of sensorineural hearing loss with very low birth weight, hyponatremia, infection, seizures, or medications was found. On the basis of these data, it is suggested that electrophysiologic hearing screening of a high risk population may be delayed until 3 to 6 months of age to improve specificity of testing.

Birth Weight↗
PubMed1987

Branched-chain amino acid carbon and nitrogen arteriovenous concentration differences across the ovine fetal hindlimb.

During fasting, branched-chain amino acids (BCAA) are thought to be major sources of nitrogen for myocyte synthesis of alanine (Ala) and glutamine (Gln), as well as possible sources of carbon skeleton for Gln synthesis. To study the relationships between Ala, Gln, and BCAA, we utilized the chronic fetal lamb preparation and measured arteriovenous concentration differences of Ala, Gln, BCAA, and branched-chain alpha-keto acids across the fetal hindlimb. Studies were performed when the ewe was fed and repeated after 1 and 5 days of complete maternal fasting. Ala and Gln are released from fetal hindquarters during fasting (arteriovenous -9.6 +/- 5 and -8.8 +/- 4.1 mumol/liter), while arteriovenous differences for BCAA simultaneously increase by 65% as compared to the fed state. During fasting, total nitrogen exiting fetal hindlimb as Ala and Gln equals nitrogen entering as BCAA. Branched-chain alpha-keto acids are released from fetal hindquarters during the fed state as well as after 1 day of fasting; at 5 days of fasting only keto-isovalerate had a net negative arteriovenous difference. In all cases, the release was much smaller than the entry of the corresponding amino acid, as determined by simultaneously measured arteriovenous concentration differences. These results indicate: Ala and Gln are released from fetal hindlimb, as in postnatal animals, during fasting, shuttling nitrogen and carbon to liver and/or other tissues. There is negligible movement of BCAA carbon as the branched-chain alpha-keto acids from hindlimb to other tissues in the fetus. BCAA carbon taken up is utilized within the hindquarters. It may be used for tissue synthesis, as an energy source, or possibly for Gln synthesis.

Amino Acids, Branched-Chain↗
PubMed1987

Hydrops fetalis.

Explore the source record for details and available documents.

Blood Group Incompatibility↗
PubMed1987

Nitrogen flux across ovine maternal and fetal hindquarters during fasting.

Nitrogen flux across the hindquarters of fetal and maternal sheep (n = 15) was determined during normal feeding and following 5 days of maternal fasting. Arterial and venous whole blood concentrations of free amino acids, ammonia and oxygen were measured entering and exiting the hindquarters. Further, the DNA, protein and nitrogen contents of the hindlimb skeletal muscle of the fetus were determined in the fed state and following the 5-day fast. Results of these studies indicate that maternal and fetal hindlimb metabolism differ during fasting. There is a net efflux of alanine, glutamine and total nitrogen from the maternal hindquarters following 5 days of fasting. The fetus also releases glutamine and alanine from the hindquarters during the fast, presumably as potential energy substrate. However, nitrogen balance across the fetal hindquarter remains positive as a result of increased positive arteriovenous differences for other amino acids (particularly leucine and isoleucine). The concentrations of DNA, protein and nitrogen in fetal skeletal muscle remain unchanged during fasting. These data indicate that, whereas the mother undergoes protein catabolism and net nitrogen loss from the hindquarter during fasting, the fetus maintains a positive nitrogen balance across the hindquarter.

Amino Acids↗
PubMed1986

Necrotizing fasciitis of the scalp in neonates.

Two premature infants with acute necrotizing fasciitis of the scalp are reported. In both cases the infection most likely arose from infiltrations of intravenous fluids into the subcutaneous region of the scalp. Aggressive surgical debridement, as well as antibiotic therapy, resulted in healing in both infants. A review of neonatal fasciitis is included.

Anti-Bacterial Agents↗
PubMed1986

Effect of a maternal fast on the urea cycle enzymes of the ovine fetus.

Activities of five urea cycle enzymes were measured in maternal and fetal sheep liver during the normal fed state and following 5 days of fasting. Six ewes and 10 fetuses were studied in both the fed and fasted periods at 132 days gestation (term: 147 days) for liver protein and enzyme levels. Results indicated that protein content increased during fasting in both the maternal and fetal liver. Fetal liver weight was decreased during fasting from 108 +/- 8.5 to 71 +/- 8.2 g (mean +/- SD) (p less than 0.001). Fed state fetal enzyme activities per gram liver were 50-125% of maternal values. After fasting, four of the five fetal enzymes increased approximately twofold to fivefold (per gram tissue) (ornithine transcarbamylase did not change). Only one enzyme (argininosuccinase) increased significantly in maternal liver. Total liver activities gave similar results. These data indicate that the in vivo studies that demonstrate a doubling in fetal urea production in the fasted sheep in later gestation are associated with parallel increases in the fetal hepatic activities of several enzymes that are responsible for urea synthesis.

Animals↗
PubMed1986

Volume of blood submitted for culture from neonates.

We prospectively examined 298 sets (298 aerobic, 299 anaerobic, and 73 resin cultures) of blood cultures from 161 critically ill newborns. The attending physicians were unaware of the study. The mean blood volume per patient (aerobic and anaerobic) was 1.05 (range, 0.11 to 3.04) ml. The mean blood volume per aerobic bottle was 0.53 (range, 0.01 to 1.90) ml. Among aerobic samples 2.7% were less than or equal to 0.1 ml, 16% were less than or equal to 0.3 ml, 33% were less than or equal to 0.4 ml, and 55% were less than or equal to 0.5 ml. For anaerobic cultures the mean blood volume was 0.52 (range, 0.01 to 1.79) ml. Among anaerobic samples 2.7% were less than or equal to 0.1 ml, 15% were less than or equal to 0.3 ml, 35% were less than or equal to 0.4 ml, and 58% were less than or equal to 0.5 ml. Blood volume did not correlate with gestational age, chronologic age, or weight. The mean volume of blood submitted in positive cultures was not significantly greater than that in negative cultures. The blood volume used for culture from ill newborns may be inadequate for detecting sepsis, and the adequacy of currently available culture methods needs to be assessed for the small samples submitted from critically ill newborns.

Aerobiosis↗
PubMed1986

Effects of fasting on gluconeogenic enzymes in the ovine fetus.

Fetal and maternal sheep were studied to determine whether changes in gluconeogenic enzyme activities could be detected in the liver and/or kidney associated with maternal nutritional deprivation. Thirteen ewes and 16 fetuses were sacrificed in the fed state, while 13 ewes with 17 fetuses were sacrificed after 5 days of fasting, all at 125 days gestation (term = 147 days). Fetal weight was decreased in the fasted versus fed group (2.86 +/- 0.56 versus 3.61 +/- 0.58 kg, p less than 0.001). Tissues were analyzed for glucose-6-phosphatase, fructose-1,6-diphosphatase, pyruvate carboxylase, phosphoenolpyruvate carboxykinase, glutamate oxaloacetate aminotransferase, and glutamate pyruvate aminotransferase. In maternal liver, four of the six enzymes increased significantly during fasting, whereas none of the enzymes increased in maternal kidney. In fetal hepatic tissue, five of the six enzymes (with the exception of pyruvate carboxylase) increased during maternal fasting and three of the enzymes increased in renal tissue. These data are consistent with the potential for increased rates of gluconeogenesis in the ovine fetus during periods of compromised maternal nutrition.

Animals↗
PubMed1986

Composition of the fetal and maternal guinea pig throughout gestation.

The guinea pig is a small animal species in which the conceptus constitutes a large proportion of maternal weight at term, thereby imposing a major metabolic demand on the mother during pregnancy. In addition the neonatal fat concentration is similar to the human making the guinea pig an interesting model for comparative physiologic study. The purpose of our study was to describe the fetal and maternal physical/chemical growth characteristics of the Hartley albino guinea pig throughout the latter half of gestation. Forty-eight pregnant adult and 122 fetal guinea pigs were sacrificed at intervals throughout gestation and the carcasses analyzed for a variety of growth parameters. The fetal growth rate during the last 8 days of gestation (5.8 g/day) was 9.7 times faster than from 30 to 40 days of gestation (0.6 g/day). The fetal mass comprised 55.4% of the maternal weight gain at term. Fetal energy increased from 403 cal/g at 30 days to 1950 cal/g at term and was paralleled by an increase in fetal fat concentration from 0.3 to 9.8% (wet weight). Nitrogen concentration increased from 0.9% wet weight at 30 days to 2.6% at term. An increasing carbon concentration and carbon:nitrogen ratio was also evident. Fetal water concentration declined from 91.6 to 67.8% during latter gestation. On a wet weight basis, the concentration of fetal sodium remained stable throughout the latter half of pregnancy; potassium, magnesium, iron, calcium, and phosphorus concentrations increased. In contrast to the changes in fetal composition, maternal energy, fat, protein, water, sodium, potassium, calcium, phosphorus, magnesium, and iron concentrations remained relatively constant throughout pregnancy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1986

Nitrogen sources for parenteral nutrition in the newborn infant.

Protein requirements for the preterm and term infant have been determined by a variety of methods. The parenteral protein needs of the very low birth weight infant are around 3 gm/kg/day and of the term infant approximately 2.2 gm/kg/day for maintenance of normal growth. These values are averages and may need to be modified for individuals depending upon a variety of potentially complicating factors. In this regard, many neonatologists recommend the provision of a maximum of 2 to 2.5 gm/kg/day of protein to newborns under most clinical situations. Whereas excessive administration of protein may result in adverse consequences, the tolerance of young infants to infusion of amino acid solutions is not well defined. Based upon animal studies of fetal amino acid utilization, the preterm infant may be capable of appropriately modifying its supply of amino acids over a relatively broad concentration range. It would appear that the supply of individual amino acids is adequately met by a number of amino acid solutions. The newer preparations appear to be more ideally suited to the special needs of the very low birth weight.

Amino Acids↗
PubMed1986

Specialized formulas and feedings for infants with malabsorption or formula intolerance.

The composition of specialized formulas for infants who experience malabsorption or formula intolerance is described in detail. The limited studies of efficacy, as well as a rationale for selecting an appropriate formula for infants with malabsorption or formula intolerance, are discussed. Infants with symptoms of diarrhea or emesis may have intolerance to milk lactose or milk protein. Soy formulas contain no lactose or cow's milk and should be the first choice of an alternative feeding because of cost and convenience. Some infants may be intolerant of soy as well as cow's milk protein. They benefit from formula containing neither cow's milk nor soy protein or from a specially processed milk-based formula containing hydrolyzed casein. A carbohydrate-free formula to which the desired type of carbohydrate is added may be helpful in the diagnosis and treatment of disaccharidase deficiencies and monosaccharide intolerances. Infants with extensive intestinal resections or intractable diarrhea may require specialized infant formulas with qualitative/quantitative modifications of fat, carbohydrate, and protein. Formulas with medium-chain triglycerides may be useful for infants with steatorrhea. "Preterm" formulas or milk from the infant's mother are preferred for preterm infants, since such feedings promote improved fat and carbohydrate absorption and better meet the infant's nutrient requirements.

Animals↗
PubMed1986

Breast-feeding the premature infant.

Although some controversy persists regarding the nutritional adequacy of breast milk for the very low birth weight infant, most authorities agree that milk expressed from the infant's biologic mother and fortified with additional minerals and protein is a proper source of nutrition. Proper support of the preterm infant and mother during expression of breast milk and during the transition to nursing requires a broad knowledge base and familiarity with the practical aspects of breast-feeding.

Breast Feeding↗
PubMed1986

Serum vitamin E levels in the very low birth weight infant during oral supplementation.

A prospective study was initiated to monitor serum tocopherol levels in all infants admitted to Indiana University Medical Center with birth weights less than 1,500 g. These infants routinely receive 100 mg/kg/d of oral vitamin E (Aquasol E tocopherol acetate) every six hours. Levels are determined weekly or semiweekly using a modification of the fluorometric method of Hanson and Warwick. Vitamin E dosage is adjusted regularly to achieve levels greater than or equal to 3.5 mg/dL. During the 6 months of this study, a total of 76 patients had 567 serum measurements. Of these, 220 levels (38%) were greater than or equal to 3.5 mg/dL, 71 (13%) were greater than or equal to 5.5 mg/dL, and 15 (2.7%) were greater than 8 mg/dL. Serum tocopherol levels often (1) remained greater than or equal to 3.5 mg/dL for several days after oral supplementation was discontinued or (2) again became greater than or equal to 3.5 mg/dL on a reduced dosage of 25 to 50 mg/kg/d. These data indicate that infants weighing less than 1,500 g at birth who are receiving oral vitamin E supplementation at 100 mg/kg/d will have varied serum levels with a significant percentage exceeding 3.5 mg/dL.

Age Factors↗
PubMed1985

Indomethacin therapy on the first day of life in infants with very low birth weight.

To investigate the optimal timing for treatment of small premature infants, we performed a double-blind, controlled trial of indomethacin therapy on the first day of life in 104 infants weighing between 700 and 1300 gm. Infants were given indomethacin or placebo at a mean age of 15 hours. Eleven of the 56 infants given placebo developed large left-to-right shunts through a patent ductus arteriosus. In contrast, only two of the 51 infants given indomethacin developed large shunts (P less than 0.025). There were no significant differences in incidence of surgical ligation, duration of oxygen therapy, duration of endotracheal intubation, days required to regain birth weight, or incidence of complications. However, the power of the tests of significance was low because of the small number of patients. Thus, although the incidence of large left-to-right ductus shunts was decreased in the indomethacin group, morbidity was not otherwise altered for the entire group of patients, possibly because of the relatively low incidence (21%) of large shunts in the placebo group. We conclude that although treatment with indomethacin on the first day of life appears to be safe, there is little advantage to its use in centers where the incidence of large shunts through a patent ductus arteriosus is relatively low.

Double-Blind Method↗
PubMed1985

Lactation and phenylketonuria.

Many young women who were diagnosed as having phenylketonuria (PKU) during routine neonatal screening and effectively treated during childhood are now of childbearing age. Recent reports suggest that maternal dietary therapy instituted before conception may improve the likelihood of a successful pregnancy and normal offspring. However, it is not known whether the intake of phenylalanine (phe) should be restricted during lactation. While phe levels in breast milk from women with PKU are markedly elevated, to our knowledge serum phe levels have not been measured in nursing newborn infants of PKU mothers. The present case report describes the pregnancy and early lactation of a mother with PKU, including serial measurements of serum phe levels in her offspring while being breast-fed.

Adult↗