Birgit Peitersen

Volumetric analysis of the normal infant brain and in intrauterine growth retardation

Twenty-eight infants with postmenstrual ages (PMA) in the range of 32-80 weeks were investigated. Twenty were newborn; among these the observed birth weight divided by the expected weight ranged from 0.31 to 1.1. Axial magnetic resonance images were recorded with a triple spin-echo sequence and the volumes were determined by encircling each structure of interest on every slice. Segmentation into grey matter, white matter and CSF was done by semi-automatic discriminant analysis. Growth charts for the cerebrum, cerebellum, corpora striata, thalami, ventricles, and grey and white matter are provided for infants with appropriate birth weight. The striatal (P = 0.02) and thalamic (P < 0.001) percentage of the hemispheric volume decreased with age, whereas the ratio of grey matter to white matter (G/W-ratio) increased (P = 0.01). In the neonatal patients, brain volumes were independently associated with both PMA and the degree of growth retardation. It was calculated that the hemispheric volume was reduced by from 16% to 23% if the total bodyweight was reduced by 40%. The G/W-ratio was found to be independently associated with the PMA (P < 0.05) and the degree of IUGR (P < 0.1) suggesting that fetal growth retardation reduces grey matter volume more than white matter.

Change of visually induced cortical activation patterns during development

continues. Laparoscopy, like surgical gloves, compromises the tactile sense. However, we believe that the improved exposure and magnification of surgical fields provided by videolaparoscopy is the major reason why this technique is eventually going to replace conventional surgery. The only way to prove our contention is through hard facts. But, as long acknowledged, randomised surgical trials tend to be

Bone mineralisation in premature infants cannot be predicted from serum alkaline phosphatase or serum phosphate

Background: The bone mineral content of premature infants at term is lower than in mature infants at the same postconceptional age. Serum alkaline phosphatase and serum phosphate are often used as indicators of bone mineralisation. Objective: To analyse the association between bone mineral content and serum alkaline phosphatase and serum phosphate. Methods: Serum alkaline phosphatase and phosphate were measured at weekly intervals during admission in 108 premature infants of gestational age below 32 weeks (mean (SD) gestational age 29 (2) weeks; mean (SD) birth weight 1129 (279) g). Bone mineral content was measured at term (mean gestational age 41 weeks) by dual energy x ray absorptiometry and corrected for body size. Results: Serum alkaline phosphatase was significantly negatively associated with serum phosphate (p < 0.001). Bone mineral content was not associated with mean serum alkaline phosphatase (p = 0.8), peak serum alkaline phosphatase (p = 0.5), or mean serum phosphate (p = 0.2) at term. Conclusion: Routine measurements of serum alkaline phosphatase and serum phosphate are of no use in predicting bone mineralisation outcome in premature infants.

Diet and Bone Mineral Content at Term in Premature Infants

Premature infants are at risk of developing metabolic bone disease mainly because of low calcium and phosphorus intake. We have examined the effect of different mineral supplements on bone mineral content at term in 127 premature infants with gestational age <32 wk in a double-blinded randomized trial. We used either phosphate supplementation of human milk as recommended by the European Society of Pediatric Gastroenterology and Nutrition or fortified supplementation with protein, calcium, and phosphorus or preterm formula as recommended by the American Academy of Pediatrics. The intervention period was from 1 week old until 36 wk of gestational age, and the infants were fed approximately 200 mL·kg−1·d−1. Bone mineral content was measured at term by dual-energy x-ray absorptiometry scan. Surprisingly, neither phosphate, fortifier, nor preterm formula supplementation had any significant effect on bone mineral content at term compared with infants fed their own mothers milk only. There was a tendency to higher total bone mineral content in infants fed preterm formula compared with infants fed their own mothers milk only (p = 0.05), but when the bone mineral content was corrected for the size of the infant, there was no difference (p = 0.68). Infants fed preterm formula had a significantly higher weight at term compared with infants fed their own mothers milk only (p = 0.02), but did not differ significantly in length or head circumference. In a regression analysis, the amount of supplemented phosphorus was significantly associated with weight at term (p = 0.008). We conclude that when feeding 200 mL·kg−1·d−1, mineral supplementation of human milk or use of preterm formula does not significantly improve bone mineralization outcome at term.

The apparent diffusion coefficient of water in gray and white matter of the infant brain.

PURPOSE The purpose was to obtain normal values of the apparent diffusion coefficient (ADC) in the infant brain and to compare ADC maps with T1- and T2-weighted images. METHOD Diffusion was measured in nine infants with an ECG-gated SE sequence compensated for first-order motion. One axial slice at the basal ganglia level was investigated with the diffusion-encoding gradients in the slice-selection direction. RESULTS On ADC maps, the corpus callosum and the optic radiations appeared dark before the onset of myelination, and the crus posterior of the internal capsule could be visualized before it appeared on T1- or T2-weighted images. In gray and white matter, the mean ADC ranged from 0.95 x 10(-9) to 1.76 x 10(-9) m2/s. In the frontal and occipital white matter, in the genu corporis callosi, and in the lentiform nucleus, the ADC decreased with increasing age. The cortex/white matter ratio of the ADC increased with age and approached 1 at the age of 30 weeks. CONCLUSION ADC maps add information to the T1 and T2 images about the size and course of unmyelinated as well as myelinated tracts in the immature brain.

Brain lactate in preterm and growth-retarded neonates

Glucose is the predominant cerebral energy source under physiological conditions, although other substrates may support cerebral metabolism. The present study was undertaken to determine if lactate is present in the immature human brain, and if so, whether or not concentrations of lactate differ between small–for–gestational–age and appropriate–for–gestational–age infants. Thirty stable, healthy infants with normal brains were investigated. As the only nutrient, all received milk enterally prior to the investigation, which was carried out without sedation. Mean gestational age was 35 completed weeks (range 28–41 weeks) and mean birth weight was 2170g (range 855–4100 g). Proton nuclear magnetic resonance spectra from the striatal region were obtained while the infants were sleeping quietly. Lactate was present in all 10 preterm small–for–gestational–age and 10 of 13 preterm appropriate–for–gestational–age infants, and the concentration was inversely related to postmenstrual age (p < 0.002). In addition, lactate increased with the degree of growth retardation (p < 0.01). At present the significance of lactate is unclear. Lactate may be produced locally or in peripheral tissues, and may support brain metabolism.

Retinopathy of prematurity : review of a seven-year period in a Danish neonatal intensive care unit

Arrae M, Peitersen B. Retinopathy of prematurity: review of a seven‐year period in a Danish neonatal intensive care unit. Acta Pædiatr 1994;83:501–5. Stockholm. ISSN 0803–5253

Infrared Analysis for Determining Macronutrients in Human Milk

Infrared (IR) analysis is widely used for routine analysis of cow milk in dairies. The aim of this study was to evaluate the precision and accuracy of an IR analyzer (Milko-scan 104) for measuring protein, fat, carbohydrate, and, indirectly, the energy content of human milk. The results of the IR analysis were compared with those of the following reference methods: protein--Kjeldahl (nitrogen minus nonprotein nitrogen); fat--Roese Gottlieb; carbohydrate--lactose enzymatic assay; energy--bomb calorimetry. The precision (repeatability coefficient of variation) of the IR results was high for all four components: protein 0.4%, fat 1.0%, carbohydrate 0.2%, and energy 0.1%. There was a close linear covariation between IR results and reference results. [Protein content was determined with an error (SD) of 0.01 g/100 ml and fat with an error of 0.03 g/100 ml.] The covariation between IR carbohydrate results and the results of the lactose assay was poor, probably because the oligosaccharides in the milk were included in the results from the IR analysis and not in the results from the lactose assay. IR analysis is a valuable method in research, especially in epidemiological surveys, in which large numbers of samples are analyzed, and for continuous monitoring of the nutritional value of human milk in milk banking programs.

Use of brain lactate levels to predict outcome after perinatal asphyxia

Perinatal asphyxia is an important cause of neurological disability, but early prediction of outcome can be difficult. We performed proton magnetic resonance spectroscopy (MRS) and global cerebral blood flow measurements by xenon‐133 clearance in 16 infants with evidence of perinatal asphyxia. Cerebral blood flow was determined daily in the first 3 days after birth in seven cases. Proton MRS was performed in 11 infants within the first week (mean 3.7 days), the rest within the first month (mean 22.2 days), and all had a scan around 3 months of age. Four infants died neonatally, three showed neurological deficits and the rest seemed to be progressing normally at neurodevelopmental follow‐up at 1 year of age. A significant correlation was found between initial brain lactate levels and severe outcome (p= 0.0003) just as between cerebral hyperperfusion (mean cerebral blood flow (CBF) 86ml(100g)‐1min‐1), (p = 0.02) and outcome. The diagnostic and prognostic implications of early MRS and CBF are predictive of poor outcome in severely asphyxiated infants.

Macronutrients in Milk from Mothers Delivering Preterm

UNLABELLED Premature infants require large amounts of protein and energy to achieve normal growth. Feeding with human milk alone is therefore only regarded acceptable if the protein and energy content is adequate. METHODS 476 milk samples from 101 mothers delivering before the 32nd gestational week (mean gestational age, 28 weeks) were obtained on a weekly basis until 36 weeks of gestational age and analyzed for true protein, total carbohydrate, and fat content by infrared analysis. Fat measurements were validated with the Folch method. Milk was collected by complete expression with an electric pump into 24-hour pools. RESULTS The protein concentration decreased significantly with time (P = 0.00001). The carbohydrate, fat, and energy concentration was significantly lower in the first 2 weeks after delivery, after which they increased to a constant level. The macronutrient level in milk was not associated with gestational age (P = 0.3). The energy content of these milk samples was high, and feeding 200 mL/kg would provide sufficient energy until 36 weeks of gestational age for all infants, and 65% of the infants would receive > or =3g total protein/kg/day.