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Lipids are considered the most important energy source in the infant diet and are necessary for normal growth and physical activity. Human milk, in which most of the energy is present as fat, provides a relatively high cholesterol intake. Formula provides a much lower cholesterol intake. Infants fed human milk have higher total and LDL-cholesterol concentrations in plasma than do formula-fed infants (P: < 0.05), whereas plasma HDL- and LDL-cholesterol concentrations are lower in formula-fed infants if a formula high in linoleate is fed (P: < 0.05). Infants adapt to the high cholesterol content of human milk through a decrease in cholesterol synthesis; in contrast, the addition of cholesterol to formula does not suppress synthesis. Measurements of serum lipoproteins and LDL-receptor activity suggest that it is the fatty acid content, rather than the cholesterol content, of the diet that regulates cholesterol homeostasis. We studied the effect of total energy, source of energy, and fat on growth indexes of children <6 y of age in Latin America with use of food balance data. With respect to availability of animal fat, a negative relation was evident for being underweight (percentage weight-for-age <2 SDs of the World Health Organization-National Center for Health Statistics standards) and for having a low birth weight; the latter was also negatively related to energy. Wasting (percentage weight-for-height <2 SDs) was not related to dietary factors. These results suggest that diets that provide <22% of energy from fat and that are low in animal fats may restrict growth. The coexistence of early stunting with adult obesity in Latin America creates a dilemma for public nutrition intervention programs.

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We report a 21-month-old female patient whose urine organic acid profile suggested a biotin utilization abnormality consistent with multiple carboxylase deficiency. For most previously reported patients, holocarboxylase synthetase deficiency has correlated with the early-onset variant of multiple carboxylase deficiency; conversely, biotinidase deficiency has been characteristic of the late-onset form. In vitro enzyme studies revealed that our patient suffered from holocarboxylase synthetase deficiency. We suggest that holocarboxylase synthetase deficiency should be considered in the differential diagnosis of older patients in whom there is suspicion of a defect in biotin metabolism.

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To evaluate the effect of varying phosphorus intake with constant high calcium intake (430 micrograms/kJ, or 180 mg/100 kcal), we randomly assigned 35 appropriate-for-gestational-age healthy male infants (birth weight, 715-1510 g) on day 21 postnatally to either standard-phosphorus (215 micrograms/kJ, or 90 mg/100 kcal), moderate-phosphorus (254 micrograms/kJ, or 106 mg/100 kcal), or high-phosphorus intake (287 micrograms/kJ, or 120 mg/100 kcal). Three-day mineral balances were determined after 7 d of the study diets. Weight and head circumference gain and intake of energy and vitamin D were not different for all groups. Calcium retentions were sufficient to meet intrauterine accretion in all groups. Phosphorus calculated to be available for soft tissue was significantly higher in the moderate- and high-phosphorus groups, and was sufficient to support soft tissue phosphorus accretion in these two groups. Total absorbed phosphorus and phosphorus tubular reabsorption were each affected by phosphorus intake. We conclude that very low birth weight infants fed high calcium may require greater phosphorus intake than that provided by formulas containing a ratio of calcium to phosphorus of 2:1. We suggest that the optimal mass ratio of calcium to phosphorus for formula for very low birth weight infants is from 1.6:1 to 1.8:1.

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A prospective study in healthy infants predefining both diet fatty acid and cholesterol, from birth to age 1 year, compared response of cholesterol fractions in three groups: random assignment to 1) monounsaturated-(Hi-Mono) (n = 20), or 2) polyunsaturated-(Hi-Poly) (n = 22) fatty acid-enriched diets, or 3) non-randomized selection to breast feeding (Human Milk) (n = 25). In each group, designated weaning foods and supplements maintained fatty acid and cholesterol intake similar to that of each group's defined formulas, with long-term compliance confirmed by plasma phospholipid fatty acid concentrations. By 12 months, total cholesterol was significantly lower in the Hi-Poly group compared to either of the other groups (P < 0.05). Low density lipoprotein (LDL)- and high density lipoprotein (HDL)-cholesterol concentrations were significantly lower by 12 months in the Hi-Poly group, compared to the Hi-Mono groups. However, at the earlier 4-month interval, total cholesterol and LDL-cholesterol in both Hi-Mono and Hi-Poly groups were not different from each other, although each was significantly lower than the parallel Human Milk-group (P < 0.05). The Hi-Mono group increased gradually in total and LDL-cholesterol such that, after 12 months' feedings, all lipid fractions of this Hi-Mono group were no different from those of the Human Milk group. In independent group comparisons, there were no significant differences in HDL-cholesterol concentrations after 4 and 9 months on these diets. Independent of diet, HDL-cholesterol showed a falling trend as an overall time-effect across all groups (P < 0.001). These data suggest that prolonged feeding of a diet enriched in polyunsaturated acids in early infancy has a significant cholesterol-lowering effect compared to monounsaturates. These differences in total, LDL-, and HDL-cholesterol plasma concentrations between polyunsaturates and monounsaturates were not significantly evident until feedings had continued for a year.

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A patient with molybdenum cofactor deficiency (producing the biochemical abnormalities associated with deficiencies of sulphite oxidase and xanthine dehydrogenase) clinically expressed Marfan-like habitus with dislocated lenses, vertebral abnormality, learning disability, moderate hemiplegia, increased medial lentiform MRI signal and intermittent microscopic haematuria. S-Sulphocysteine was present in plasma and urine, and the oxidized derivative of a molybdopterin precursor (precursor Z), together with xanthine and hypoxanthine, were elevated in urine. Blood uric acid was < 1 mg/dl, while urinary urothione was not detected. These data indicate a functionally inadequate terminal enzyme for converting precursor Z to active molybdopterin (complementation group B of general molybdenum cofactor deficiency). Although the biochemical parameters were indicative of a severe deficiency state, the patient has survived into the third decade with a less severe clinical spectrum than has generally been associated with this disease.

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3-Methylglutaconic aciduria was detected in four patients with Pearson syndrome, a multitissue disorder with hematologic abnormalities, lactic acidosis resulting from defective oxidative phosphorylation, and deletions in the mitochondrial genome. 3-Methylglutaconic acid may be an additional useful marker for Pearson syndrome and may be a more specific marker than other organic acids identified in this disorder.

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The effects of three dietary phosphorus concentrations on magnesium balance in very low birth weight (VLBW) infants were measured. The infants consumed one of three special formulas for 20 consecutive days. Magnesium balance was calculated by measuring food intake, urinary magnesium and fecal magnesium. The highest dietary phosphorus concentration resulted in a higher (P < 0.05) fecal loss of magnesium. Net absorption and net retention of magnesium were lower (P < 0.10) in the high phosphorus group. A modest (33 per cent) increase in dietary phosphorus resulted in a decrease in magnesium absorption in VLBW infants.

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Skeletal muscle hypotonia is a hallmark clinical finding in very-low-birth-weight (VLBW) human infants. Although the biochemical basis for this phenomenon is not completely understood, one hypothesis is that the phosphorylation potential is abnormally low in the skeletal muscle of these infants. Therefore, we used 31P-nuclear magnetic resonance (NMR) spectroscopy to measure phosphorus metabolites in the skeletal muscle of VLBW infants during rest and during reflex-induced muscle contractions. Compared with healthy larger infants or to adults, the total phosphorus NMR signal is lower in VLBW infants. In VLBW infants during rest, [PCr]/([PCr]+[Pi]), where PCr is phosphocreatine and brackets denote concentration, was 89% and [ATP]/[ADP][Pi] was 59% of that found in larger infants (P less than 0.05). During reflex-induced isometric contractions in VLBW infants, [PCr]/([PCr]+[Pi]) declined by 24% and [ATP]/[ADP][Pi] declined by 35% (P less than 0.05 vs. rest). In all conditions, muscle pH remained 7.1. Overall, the differences in skeletal muscle energy state during rest and the corresponding changes in concentration of high-energy phosphates during mild exercise suggest a very limited energy reserve in the hypotonic muscle of VLBW infants.

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The effect of a low milk fat yield was assessed in a blinded prospective study of healthy term infants and mothers encouraged to breast-feed. Fat yield index was calculated as milk volume collected by Egnell pump multiplied by the "creamatocrit." Two weeks after delivery mothers who had a relatively low fat yield index (less than or equal to 30th percentile) were matched with mothers with a higher fat yield index and with formula-feeding mothers. Between 2 and 6 weeks the low fat yield group had a marginally lower weight gain but similar growth in length and head circumference to that of the higher fat yield group. The low fat yield group spent more time per feeding and had more complete breast emptying, resulting in a fat yield index comparable with the higher fat yield group for the mean milk volume ingested by the infant at 6 weeks. A low fat yield had no adverse effect on maternal satisfaction or maternal-infant interaction during feeding. Formula feeders spent the least time in feeding and en face gazing. Adaptation of breast-feeding to a low fat yield sustains infant intake and growth, maternal-infant interaction, and maternal satisfaction. However, there is little reserve if milk production diminishes. Further study is needed to define the limits of adaptation and effective interventions if fat yield is inadequate.

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The Pearson marrow-pancreas syndrome is a fatal disorder involving the hematopoietic system and the exocrine pancreas in early infancy. We have previously shown that this disease results from a widespread defect of oxidative phosphorylation. Here, we describe deletions of the mitochondrial (mt) genome between repeated 8- to 13-bp sequences as consistent features of the disease. Studying a series of nine unrelated children, including the patient originally reported by H. Pearson, we found five different types of direct repeats at the boundaries of the mtDNA deletions and we provided evidence for conservation of the 3'-repeated sequence in the deletions. In addition, we found a certain degree of homology between the nucleotide composition of the direct repeats and several structures normally involved in mtDNA replication and mtRNA processing. These results are consistent either with the recognition and cleavage of a particular DNA sequence with a factor of still unknown origin or with a homologous recombination between direct-repeat mtDNA sequences in the Pearson syndrome.

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Two similar cohorts of low birth weight infants whose size was appropriate for gestational age randomly received either aztreonam-arginine plus ampicillin (n = 15) or gentamicin plus ampicillin (n = 15) for empiric treatment of neonatal sepsis. The regimens were infused together with glucose at greater than 5 mg/kg per minute, and immediate (4 hours) and cumulative (3 days) effects were assessed. Serum arginine and insulin values rose immediately after administration of aztreonam (containing 0.15 mmol of arginine per kilogram), but there were no changes in the gentamicin-treated cohort; no differences occurred in either cohort in serum concentrations of glucose, ammonia, potassium, creatinine, and bilirubin. After 3 days of antibiotic therapy (n = 13), the baseline serum arginine concentration was almost twice as high in the aztreonam group and showed a similar further rise and fall during the 4 hours after infusion; arginine urinary fractional excretion (normalized to creatinine clearance) decreased in the gentamicin group. The indirect bilirubin concentration rose more (p less than 0.001) in the aztreonam-treated infants (5.1 to 11.5 mg/dl (87 to 196 mumol/L] than in the gentamicin-treated infants (5.5 to 8.1 mg/dl (94 to 138 mumol/L)). Thus a modest differential bilirubin response and modestly elevated baseline serum arginine level occurred after the 3-day low-arginine doses of this study; serum ammonia and glucose concentrations were not affected. Aztreonam-arginine in neonates was well tolerated metabolically, and we believe that it can be used safely in conjunction with attention to glucose and bilirubin metabolism.

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Traditionally, standards are used to define the level of care that a patient can expect to receive in a given institution or on a given nursing unit. These standards are the foundation of quality assurance programs. Unfortunately, with the increased emphasis on monitoring care, many standards are being written after the quality assurance activities have been developed and are in place. Often, standards are placed neatly in a book that is dusted off and brought out when the Joint Commission for Accreditation of Healthcare Organizations representative (JCAHO) visits. The nursing staff at the unit level has no real knowledge or understanding of the standards. This may result in a nonfunctioning quality assurance program.

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The clinical and magnetic resonance imaging findings of a 14-year-old boy with Pearson syndrome are presented. The patient represents the oldest living survivor of the original four patients described by Pearson and associates. This syndrome has recently been found to be associated with an mtDNA deletion. The patient reported here has a deletion similar but not identical to that reported in the literature. Several mitochondrial myopathies have been associated with mtDNA deletions, with considerable overlap between and among the phenotypes and underlying mtDNA deletions. The same may well prove to be true for Pearson syndrome.

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We investigated postasphyxial brain damage with 31P magnetic resonance spectroscopy (MRS) and correlated it with neurologic assessment and standard laboratory evaluation during the first 10 months of life in 1 infant, baby G. We compared these observations to 31P MRS data from 7 healthy term newborns, 1 normal infant examined serially over the first 8.5 months of life, and 5 other term infants following perinatal asphyxia. MRS noninvasively provides biochemical correlates of the evolution of brain damage following perinatal asphyxia and suggests that pH derived from the inorganic phosphate peak may serve as a marker for brain injury.

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Taurine may be important to the developing eye and brain of the small preterm infant. A blinded randomized trial was conducted to determine whether taurine supplementation of healthy infants of less than or equal to 1,300 g birth weight until their discharge from the hospital increases their growth rate, neurobehavioral development, electroretinographic development, or maturation of auditory brainstem-evoked responses. Infants were fed with Similac Special Care as desired, which was prepared to contain less than 5 mg/L of taurine or 45 mg/L of taurine, a concentration similar to that of human milk. Infants who did not receive taurine supplementation (n = 19) and those who did (n = 18) were similar with respect to condition at study entry, caloric intake, and growth rates throughout the study, and electroretinographic findings and scores on the Brazelton Behavioral Assessment Scale at 37 weeks' postmenstrual age. Infants who received taurine supplementation had greater overall plasma taurine concentrations. The group receiving taurine supplementation also had more mature auditory-evoked responses at 37 weeks' postmenstrual age with a modest (0.2 to 0.5 ms) but consistent reduction (P less than .05) in the interval between stimulus and response at two different stimulation rates. Although further study is needed, taurine intake appears to influence auditory system maturation of preterm infants.

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