Partition of energy metabolism and energy cost of growth in the very low-birth-weight infant.

Energy requirements are partitioned between needs for maintenance (including resting metabolism, thermoregulation, and muscular activity) and needs for synthesis and storage of new tissue. The partition of energy utilization was evaluated by 22 metabolic and nutritional balance studies in 13 formula-fed (SMA 20/24), growing, appropriate-for-gestational age, very low-birth-weight infants (mean +/- SE birth weight, 1,155 +/- 39 gm; study weight, 1,271 +/- 60 gm; age at study, 21 +/- 2 days; weight gain, 16.8 +/- 1 gm/kg/day). Continuous open-circuit, indirect calorimetry was performed for periods of 6 +/- 0.25 hours in a thermoneutral environment. Results expressed as mean kilocalories per kilogram per day (+/- SE) were: energy intake, 148.6 (+/- 3.9); stool and urine losses, 18.2 (+/- 1.5); metabolizable energy, 130.4 (+/- 3.5); "basal" metabolic rate, 47.0 (+/- 0.75); energy cost of activity, 4.3 (+/- 0.9); thermic effect of food, 11.3 (+/- 0.65); energy stored in new tissue, 67.8 (+/- 3.0). These results provide a partition of energy utilization in very low-birth-weight infants under thermoneutral conditions. Increased activity and a thermal environment outside the neutral range will augment maintenance energy requirements, thus decreasing the amount of energy available for growth if metabolizable energy intake remains constant. The energy cost of growth (ie, for synthesis of, and storage in, new tissue) was determined as 4.9 kcal/gm of weight gain. To attain the equivalent rate of intrauterine weight gain, a metabolizable energy intake of approximately 60 kcal/kg/day in excess of maintenance requirements of 51.3 kcal/dk/day must be provided.

Primary aortoduodenal fistula in combination with aortoiliac occlusive disease: report of a rare case.

Most of the cases of aortoenteric fistula are due to aneurysm of the aorta, although infection, tumor, radiotherapy, gastric ulcers and foreign body ingestion have also been described in the literature. We report the case of a 62-year-old woman presenting with massive gastrointestinal bleeding with hematemesis and melaena. This case is unique in that the primary aortoduodenal (PADF) fistula formed as a result of complex atherosclerotic disease of the abdominal aorta and both iliacal arteries, also known as Leriche's syndrome, and not primarily due to an aneurysm. We will give a brief summary of the difficulties and challenges which the surgeon faced during the operation and a surprisingly uneventful postoperative course.

Development and maturation of the autonomic nervous system in premature and full-term infants using spectral analysis of heart rate fluctuations.

The changes in the power spectra of heart rate (HR) fluctuations, in particular the total power (within 0.02-2.0 Hz) and the power in the low- (0.02-0.2 Hz) and high- (0.2-2.0 Hz) frequency ranges, were computed from the ECG and respiratory signals of 59 premature and full-term infants. The objective of the study was to investigate the development and maturation of the autonomic nervous system from the first day of extrauterine life to several weeks of postnatal age. The study population was divided into four age groups. Group A: seven 1-d-old premature infants with gestational age of 34-35 wk. Group B: 28 premature infants 7-49 d old with a conceptional age of 34-35 wk. Group C: seven 1-d-old full-term infants of 39-41 wk gestation. Group D: six premature infants 35-97 d old with a conceptional age of 39-40 wk. Mean HR (+/- SEM) of groups C and D combined, i.e. 135 +/- 2 bpm, was significantly lower compared with groups A and B, i.e. 152 +/- 2 (p < 0.01). The mean (+/- SEM) of the low- to high-frequency power ratio obtained from the HR power spectrum decreased progressively from 71 +/- 31 in group A to 34 +/- 8 in group B, 16 +/- 3 in group C, and 17 +/- 2 in group D. The mean low to high ratio for the combined groups C and D, 17 +/- 1, was significantly lower compared with the combined group A and B, i.e. 44 +/- 9 (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Participation of a histamine-Sepharose-adherent subpopulation of human mononuclear cells in the production of leucocyte migration inhibition factor (LIF) in healthy children.

The separation of mouse splenic T lymphocytes into distinct subpopulations by fractionation on histamine-rabbit serum albumin Sepharose (H-RSAS) columns has been described. The H-RSAS-adherent T cells have been attributed regulatory functions associated with B cell activity, T cell-mediated cytotoxicity and the secretion of mediators such as immuno-interferon. The possibility that H-RSAS-adherent T cells exert a similar regulatory effect on an in vitro parameter of T cell-mediated immunity was investigated by assaying the production of leucocyte migration inhibition factor (LIF) in human blood samples, using the agarose droplet method. Phytohaemagglutinin (PHA) and BCG-purified protein derivative (PPD) were used as stimulants of LIF secretion which was measured as a percentage of inhibition of linear leucocytic migration. In normal individuals a highly significant (P less than 0.001) decrease was demonstrated in the production of LIF by peripheral blood leucocytes depleted of H-RSAS-adherent cells. Migration inhibition dropped from 36 +/- 11.7% to 21.2 +/- 12.9% in eighteen cases tested with PHA and from 29.3 +/- 11.7% to 17.2 +/- 9.8% in twelve cases tested with PPD. These results suggest the existence of a lymphocytic subpopulation involved in LIF production which expresses histamine receptors.

Relation between heart rate and energy expenditure in the newborn.

This study defines the relationship between heart rate and metabolic rate in newborn infants and evaluates the accuracy of prediction of metabolic rate from heart rate. Continuous measurements of oxygen uptake, CO2 production, respiratory quotient, and cumulative heart rate were performed using computerized, open-circuit indirect calorimetry and on-line electrocardiogram monitoring over periods of 1 to 24 hr (mean 4.5 hr). Metabolic rate was calculated from the individual oxygen uptake and respiratory quotient. Thirty-five studies were performed in 16 infants (birthweight 0.75 to 3.1 kg; gestational age, 26 to 42 wk; mean +/- S.D. age at study, 26.5 +/- 15.7 days; study weight, 1.78 +/- 0.5 kg). Metabolic rate (cal/kg . min) and heart rate (beats/min) were compared minute by minute (8269 measurements) and showed a close third degree polynomial relationship for heart rates of 110 to 230/min (y = -0.0000291x3 + 0.01685x2 -2.93x + 197; r = 0.99; P less than 0.001); however, at heart rates above 140 beats/min, a linear relationship was found (r = 0.997; P less than 0.001). From cumulated heart rate measurements, factors defining metabolic rate per heart beat were also determined: for each beat 51.8 +/- 6.8 microliter of oxygen/kg are consumed and 0.258 +/- 0.03 cal/kg (1.1 J/kg) are expended. Despite the wide variation in birthweight, gestational age, method of feeding, and clinical characteristics, there was a remarkable consistency in the heart rate-metabolic rate relationships. A further 10 studies were performed in a similar group of infants to assess the predictive value of the previously defined relationships and showed a mean percentage deviation of 5.7 +/- 4% from the measured value. We conclude that in the varied group of newborns studied, heart rate correlates closely with metabolic rate and that cumulative heart rate measurements enable the estimation of metabolic rate in newborn infants. This provides a method of monitoring energy expenditure and caloric requirements over long periods.

Influence of postnatal age, energy intake, and weight gain on energy metabolism in the very low-birth-weight infant.

The relative importance and interrelationship of postnatal age, energy intake, and weight gain on metabolic rate is evaluated in 28 studies in 13 formula-fed very low-birth-weight AGA infants. The relationships between metabolic rate, energy intake, weight gain, and age all follow a similar pattern, increasing in the first two weeks of life and subsequently stabilizing. Significant linear correlations are demonstrated between metabolic rate and both energy intake (r = 0.88, P less than 0.001) and weight gain (r = 0.86, P less than 0.001). For each gram of weight gain, 0.67 kcal (2.8 kj) are expended in addition to the maintenance energy requirement of 51 kcal/kg/day. The increase in metabolic rate in the early postnatal period appears to be a consequence of the energy cost of tissue synthesis. Changes in metabolic rate with postnatal age are modulated by increasing energy intake and weight gain.