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Biomedical subjects

E F Bell

Publications and source records attributed to E F Bell.

At least 37 records · Page 2Linked to original sources
PubMed1991

Infrared thermometry of newborn infants.

An infrared thermometer, the FirstTemp, was tested among newborn infants by comparing tympanic membrane temperature measurements in three operating modes, "Cal-tympanic," "Cal-surface," and "Cor-tympanic," with nearly simultaneous tympanic membrane, rectal, and axillary temperature measurements using other standard methods. The FirstTemp underestimated other measurements of body temperature in the "Cal-tympanic" mode and overestimated them in the "Cor-tympanic" mode. In the "Cal-surface" mode, the First-Temp readings were significantly lower than tympanic membrane temperatures measured with a thermistor probe and electronic thermometer (mean difference 0.2 degrees C) but not significantly different from rectal or axillary temperatures. According to these results, the FirstTemp can be used reliably in the "Cal-surface" mode but not in the "Cal-tympanic" or "Cor-tympanic" mode. Its speed and ease of operation offer significant advantages over traditional clinical methods of temperature measurement.

Axilla↗
PubMed1990

Variability of abdominal circumference of premature infants.

Serial measurements of abdominal circumference were made in 27 premature infants 1 hour before feeding, immediately before and after feeding, and 1 and 2 hours after feeding. In some infants these measurements were repeated for 2 (n = 18) or 3 (n = 3) consecutive days. All 258 measurements were performed by the same examiner; 124 were also repeated blindly by another examiner to test interobserver reliability. The coefficient of variation of repeated measurements of any one infant by the same examiner on a single day was 2.7%. Ninety percent of repeated measurements agreed within 1.5 cm. The interobserver reliability was 0.99. Abdominal circumference was positively correlated with birth weight (P = .0001) and time from last defecation (P = .0001) and negatively correlated with time from last feeding (P = .04). Increases in abdominal circumference of less than 1.5 cm occur normally and, in the absence of other clinical signs, should not be considered indicative of disease.

Abdomen↗
PubMed1990

Repeated ingestion of aspartame-sweetened beverages: further observations in individuals heterozygous for phenylketonuria.

Six adults heterozygous for phenylketonuria (PKU) ingested eight successive servings of unsweetened and aspartame (APM)-sweetened beverage at 1-hour intervals in a randomized, balanced, crossover design. In one part, the eight beverage servings were not sweetened. In the other, each of the eight beverage servings provided 600 mg of APM, a dose equivalent to the amount provided by 36 oz of an APM-sweetened diet beverage. Plasma aspartate concentration was not significantly increased after ingestion of unsweetened or APM-sweetened beverage. Similarly, ingestion of the unsweetened beverage had no significant effect on plasma phenylalanine concentration. However, ingestion of APM-sweetened beverage significantly increased plasma phenylalanine concentrations 2.35 to 4.03 mumol/dL above baseline 30 minutes after ingestion. Plasma phenylalanine values reached a steady-state after administration of five servings of APM-sweetened beverage and were slightly, but significantly higher than usual postprandial values for adults heterozygous for PKU. Similarly, the ratio of the plasma phenylalanine concentration to the sum of the concentration of the large neutral amino acids was significantly higher than usual postprandial values. Blood methanol and formate concentrations remained within normal limits. These data indicate that a fasting adult heterozygous for PKU could consume the equivalent of 24 12-oz servings of APM-sweetened beverage over an 8-hour period and only increase plasma phenylalanine concentration to a modest degree.

Adult↗
PubMed1990

Aspartame ingestion with and without carbohydrate in phenylketonuric and normal subjects: effect on plasma concentrations of amino acids, glucose, and insulin.

Seven subjects homozygous for phenylketonuria (PKU) and seven normal subjects were administered four beverage regimens after an overnight fast: unsweetened beverage, beverage providing carbohydrate (CHO), beverage providing aspartame (APM), and beverage providing APM plus CHO. The APM dose (200 mg) was the amount provided in 12 oz of diet beverage; the CHO was partially hydrolyzed starch (60 g). Plasma amino acid concentrations were determined after dosing and the molar plasma phenylalanine (Phe) to large neutral amino acid (LNAA) ratio calculated. APM administration without CHO did not increase plasma Phe concentrations over baseline values in either normal or PKU subjects (5.48 +/- 0.85 and 150 +/- 23.0 mumols/dL, respectively). Similarly, the Phe/LNAA did not increase significantly. Ingestion of beverage providing APM and CHO did not significantly increase plasma Phe concentrations over baseline values in either normal or PKU subjects. However, ingestion of beverage providing CHO (with or without APM) significantly decreased plasma levels of valine, isoleucine, and leucine 1.5 to 4 hours after dosing in both normal and PKU subjects, thereby increasing the Phe/LNAA ratio significantly. These data indicate that changes noted in Phe/LNAA values after ingestion of beverage providing APM plus CHO were due to CHO. The plasma insulin response to beverage providing CHO (with or without APM) was significantly higher in PKU subjects than in normals.

Adolescent↗
PubMed1990

Effect of sucrose on the metabolic disposition of aspartame.

Twelve normal adult subjects ingested a beverage providing 0.136 mmol aspartame/kg body wt on 2 different days. On 1 study day the beverage provided only aspartame, on the other the beverage provided both aspartame and 3.51 mmol sucrose/kg body wt. The high mean plasma phenylalanine concentrations were similar after administration of aspartame alone (158 +/- 28.9 mumol/L, mean +/- SD) and administration of aspartame plus sucrose (134 +/- 44.1 mumol/L). Evaluation of the area under the plasma concentration-time curve (AUC) for phenylalanine also showed no significant difference between groups (197 +/- 49.1 vs 182 +/- 28.3 mumol.L-1.h for aspartame alone and aspartame plus sucrose, respectively). Similarly, the high mean ratio of phenylalanine to large neutral amino acids (Phe:LNAA) in plasma did not differ significantly (0.265 +/- 0.046 for aspartame alone, 0.275 +/- 0.107 for aspartame plus sucrose). However, there was a small but significant difference between groups for the 4-h AUC values for plasma Phe:LNAA. The simultaneous ingestion of sucrose with aspartame had only minor effects on aspartame's metabolic disposition.

Adult↗
PubMed1989

Effect of repeated ingestion of aspartame-sweetened beverage on plasma amino acid, blood methanol, and blood formate concentrations in normal adults.

Aspartame (APM) is a widely used dipeptide sweetener (L-aspartyl-L-phenylalanine methyl ester). It has been suggested that excessive use of APM might elevate plasma aspartate, phenylalanine, and/or methanol concentrations to levels that are potentially harmful. Six normal young adults ingested eight successive servings of unsweetened and APM-sweetened beverage at one-hour intervals in a balanced crossover design. In one part, the beverage was not sweetened. In the other, each serving of beverage provided 600 mg APM, a dose equivalent to the amount provided by 36 oz of APM-sweetened diet beverage. Plasma aspartate concentration was not significantly increased after ingestion of unsweetened or APM-sweetened beverage. Similarly, ingestion of the unsweetened beverage had no significant effect on plasma phenylalanine concentration. However, ingestion of APM-sweetened beverage significantly increased plasma phenylalanine levels 1.41 to 2.35 mumol/dL above baseline 30 minutes after ingestion. Plasma phenylalanine values reached a steady state after administration of four to five servings and did not exceed normal postprandial values at any time. Blood methanol and formate concentrations remained within normal limits. The data indicate ready metabolism of APM when administered at levels that may be ingested by normal individuals who are heavy users of diet beverages.

Adult↗
PubMed1989

Repeated ingestion of aspartame-sweetened beverage: effect on plasma amino acid concentrations in individuals heterozygous for phenylketonuria.

It has been suggested that excessive use of aspartame (APM) (N-L-alpha-aspartyl-L-phenylalanine methyl ester) might grossly elevate plasma aspartate and phenylalanine concentrations in individuals heterozygous for phenylketonuria (PKUH). In study 1 six adult PKUH (three males; three females) ingested three successive 12-oz servings of beverage at 2-h intervals. The study was carried out in two parts in a randomized crossover design. In one arm the beverage was not sweetened. In the other the beverage provided 10 mg APM/kg body weight per serving. The addition of APM to the beverage did not significantly increase plasma aspartate concentration but did increase plasma phenylalanine levels 2.3 to 4.1 mumol/dL above baseline values 30 to 45 min after each dose. The high mean plasma phenylalanine level after repeated APM dosing (13.9 +/- 2.15 mumol/dL) was slightly, but not significantly, above the normal postprandial range for PKUH (12.6 +/- 2.11 mumol/dL). In study 2 six different adult PKUH ingested beverage providing 30 mg APM/kg body weight as a single bolus. The high mean plasma phenylalanine concentration and the phenylalanine to large neutral amino acid ratio were significantly higher when APM was ingested as a single bolus than when ingested as a divided dose.

Adult↗
PubMed1989

Upper limit of vitamin E in infant formulas.

Reports of toxicity to enterally administered vitamin E are rare in infants. However, increased risks of sepsis and necrotizing enterocolitis have been reported after both enteral and parenteral vitamin E, primarily when plasma (or serum) vitamin E levels exceed 3.5 mg/dl. Levels this high are seldom seen with enteral vitamin E when intake is 25 mg d-alpha-tocopherol equivalent/(kg.d) or less. Intakes below this threshold will be provided by infant formulas with vitamin E to energy ratios of up to 20 mg/100 kcal (30 IU/100 kcal) so long as energy intake does not exceed 125 kcal/(kg.d). To allow a margin of safety, it would be reasonable to limit the amount of vitamin E added to the formula during its manufacture to half this amount, or 10 mg/100 kcal (15 IU/100 kcal). This level coincides with the highest levels of vitamin E found in human colostrum and is 20 times the recommended lower limit for vitamin E in infant formula of 0.5 mg/100 kcal.

Adult↗
PubMed1989

Effects of furosemide on body water compartments in infants with bronchopulmonary dysplasia.

We studied the effects of a single dose of intravenous furosemide on the body water compartments of nine infants with bronchopulmonary dysplasia. We measured total body water, extracellular water, and plasma volume using deuterium oxide, sodium bromide, and Evans blue dye, respectively. From the results of these measurements, we calculated cell water, interstitial water, red cell volume, and total blood volume. We performed these measurements on the first day of the study and again 28 h later, 4 h after an intravenous dose of furosemide (1 mg/kg). All infants had a brisk diuresis in the first hour after the dose, but urine output was no greater during the 24-h period after the dose than during the preceding 24-h period. Total body water, extracellular water, and interstitial water were significantly decreased 4 h after furosemide. There was no change in plasma volume, red cell volume, or total blood volume.

Body Fluid Compartments↗
PubMed1989

Antipyrine interferes with chemical determination of bromide in simultaneous estimation of total body water and extracellular water.

Antipyrine and bromide dilution are frequently used to estimate total body water and extracellular water volumes, respectively. We assessed a potential error with the simultaneous use of these methods. In vitro the bromide concentration of solutions measured by the gold chloride or rosaniline methods decreased linearly with increasing concentrations of antipyrine. With the gold chloride method, the "inhibitory" effect of antipyrine was more pronounced for solutions in plasma than in those in water. With the rosaniline method, the "inhibitory" effect was similar for water and plasma. Antipyrine had no effect on bromide concentration measured by fluorescein or fluorescence excitation methods. We conclude that antipyrine potentially affects the measurement of bromide space by certain colorimetric methods. The mean values of previously published data do not appear to have been affected by the technical problems described in this study, although these problems may account, at least in part, for the large variability of the results.

Antipyrine↗
PubMed1987

Plasma amino acid concentrations in normal adults administered aspartame in capsules or solution: lack of bioequivalence.

Some clinical studies require administration of test compounds in capsules to assure that the compound cannot be distinguished from a placebo. This raises the question of whether the pharmacokinetic responses produced by capsule administration are similar to values obtained when test compounds are ingested in solution. To test this, plasma phenylalanine and aspartate concentrations were compared in ten normal subjects ingesting 3 g aspartame in solution and in capsules in a balanced Latin square design. Peak plasma phenylalanine levels were significantly higher (191 +/- 65.4 v 117 +/- 39.5 mumol/L, mean +/- SD) and were reached significantly earlier (32 +/- 15 v 123 +/- 74 minutes) when aspartame was administered in solution than when it was administered in capsules. The area under the four-hour plasma phenylalanine concentration-time curve was significantly higher (15,340 +/- 4,820 v 8,465 +/- 3,356 mumol/L X min) when aspartame was ingested in solution. Administration in solution also produced a significantly higher ratio of plasma phenylalanine concentration to the sum of the plasma concentrations of the other large neutral amino acids (0.36 +/- 0.12 v 0.23 +/- 0.06). Similarly, peak plasma aspartate concentrations were significantly higher 26.2 +/- 16.3 v 10.4 +/- 5.0 mumol/L) and were reached significantly earlier (30 +/- 14 v 106 +/- 61.3 min) when aspartame was administered in solution. The data indicate different plasma phenylalanine and aspartate pharmacokinetics between solution and capsule administration of aspartame.

Adult↗
PubMed1987

Effects of formula temperature on postprandial thermogenesis and body temperature of premature infants.

To study the effect of formula temperature on the thermogenic response to gavage feeding, we fed formula at room temperature (mean 24.0 degrees C, SD 1.1) and at body temperature (mean 36.9 degrees C, SD 1.7) to premature infants in a crossover design while monitoring their metabolic heat production and gastric, rectal, and skin temperatures. After feeding with room temperature formula, stomach temperature fell by 6.9 degrees C, rectal temperature by 0.2 degree C, and mean skin temperature by 0.6 degree C, and metabolic rate increased by 16% in the first postprandial hour. After body temperature feedings, mean skin temperature fell by 0.2 degree C, but stomach and rectal temperatures did not change appreciably. The metabolic rate rose by 12% in the first hour, which was not significantly less than the rise after room temperature feeding. The heat required to warm the formula to body temperature did not result in a detectably greater rise in metabolic rate after cool feeding than after warm feeding. The effects of feed temperatures below room temperature were not studied, but it remains possible that cooler feedings might produce even greater body cooling and a greater thermogenic response.

Basal Metabolism↗
PubMed1987

History of vitamin E in infant nutrition.

Vitamin E was discovered by Evans and Bishop in 1922. Work in the 1930s revealed the chemical structure and the biological function of alpha-tocopherol. In the 1940s Filer and others demonstrated that vitamin E protects tissue unsaturated fatty acids against oxidation. The 1940s and the 1950s marked the beginning of interest in the role of vitamin E in infant nutrition. During this period, investigators examined the intestinal absorption of vitamin E in infants and its use for the prevention of hemolysis, retrolental fibroplasia, intracranial hemorrhage, and pulmonary oxygen toxicity. These studies were the forerunners of more recent studies examining possible benefits of vitamin E therapy in premature infants. Recent studies confirmed earlier reports indicating that enteral administration of vitamin E is the safest and most effective route in infants. Although preventing vitamin E deficiency is clearly necessary, neither earlier nor more recent work has shown any benefit from high-dose vitamin E therapy (greater than 20 IU X kg-1 X d-1) for premature infants.

History, 20th Century↗
PubMed1987

Aspartame-sweetened beverage: effect on plasma amino acid concentrations in normal adults and adults heterozygous for phenylketonuria.

Twelve normal subjects ingested either unsweetened beverage (n = 6) or beverage providing 4 mg/kg body weight as aspartame (APM) (n = 6). Neither beverage had any significant effect on plasma aspartate or phenylalanine concentrations. After this study, eight normal and six obligate phenylketonuric (PKU) heterozygous adults each ingested a 354-mL (12-oz) beverage serving on two occasions in a randomized cross-over design. On one occasion the beverage was not sweetened; on the other occasion, the beverage provided 10 mg APM/kg body weight. Plasma amino acid concentrations were measured throughout the 2-h study period. The addition of 10 mg APM/kg body weight to the beverage had no significant effect on plasma aspartate concentration. APM ingestion increased plasma phenylalanine levels of normal subjects from a mean +/- SD baseline value of 5.09 +/- 0.82 mumol/dL to a high mean value of 6.73 +/- 0.75 mumol/dL. In PKU heterozygous subjects the plasma phenylalanine level increased from a mean +/- SD of 9.04 +/- 1.71 to a high mean value of 12.1 +/- 2.08 mumol/dL. The data indicate ready metabolism of the aspartate and phenylalanine portion of APM when administered at levels likely to be ingested by individuals who drink diet beverages.

Adult↗
PubMed1987

Oral vitamin E supplementation for the prevention of anemia in premature infants: a controlled trial.

Serum vitamin E levels are reduced in newborn infants. It has been reported that this deficiency is responsible, in part, for the development of anemia in premature infants during the first 6 weeks of life. The efficacy of vitamin E supplementation for the prevention of anemia in premature infants has been studied in a randomized, controlled, and blinded trial. Premature infants whose birth weights were less than 1,500 g were given, by gavage, 25 IU of dl-alpha-tocopherol or a similar volume of the drug vehicle. Treatment was continued for the first 6 weeks of life. A total of 178 infants were studied. Vitamin E levels were significantly higher in a supplemented group by day 3 and for the remainder of the 6-week period. At 6 weeks of age, there was no significant difference between the supplemented and unsupplemented groups in hemoglobin concentration, reticulocyte and platelet counts, or erythrocyte morphology. It is concluded that there is no evidence to support a policy of administering vitamin E to premature infants to prevent the anemia of prematurity.

Anemia, Neonatal↗
PubMed1986

Head insulation for premature infants in servocontrolled incubators and radiant warmers.

We evaluated the safety of insulating the heads of premature infants in servocontrolled thermal environments. We measured the body temperatures of premature infants (seven in incubators, seven under radiant warmers) before, during, and after application of a head-wrap made with an olefin and polyester composite (Thinsulate, 3M Co, St Paul). All infants were tested while abdominal skin temperature was maintained at a constant level by servocontrol. Temperatures of the tympanic membrane, rectum, abdomen, and heel remained constant. The insulated headwrap increased the scalp temperature of incubator infants but not radiant warmer infants. Head insulation reduced variability in scalp temperature for radiant warmer infants. We found no evidence of overheating in these infants.

Body Temperature↗