5 breast-fed and 5 bottle-fed infants, all living in an area with 1 ppm F in the drinking water, were studied in a metabolic ward for 48 h. Samples were taken from breast milk in conjunction with suckling and the provided water-diluted baby formula. All urine and feces were collected. The F concentration in the breast milk ranged from 4 to 8 ng/ml (0.2–0.4 μM), resulting in a daily F dose of about 6 μg. The baby formula-fed infant received daily F doses ranging from 891 to 1,012 μg. Thus, the latter group received more than 150 times more F. The breast-fed infants were in a negative F balance, excreting more F than they ingested. The bottle-fed infants, on the other hand, retained more than 50% of the ingested F dose. The rapidly growing skeleton certainly enhances F retention, but a contributing factor might also be a slow elimination rate for F, caused by a not fully developed renal handling capacity for F at this early stage of life.
Reported contents of fluoride (F) in human milk vary considerably. The aim of this study was to determine the F content in human milk under different levels of F intake using a siliconfacilitated microdiffusion technique, which had a good accuracy and precision. The mean F concentration of colostrum from mothers in a 1.0 ppm and a 0.2 ppm F area was 0.36 +/- 0.02 mumol/l (+/- SEM) and 0.28 +/- 0.02 mumol/l, respectively. The mean F concentration of mature milk from a 1.0 ppm F area was 0.37 +/- 0.04 mumol/l. Within the 1.0 ppm F area, the intra- and interindividual differences in F concentration were very small. No statistically significant difference in milk F concentration between the two areas was found. Consequently, breastfed infants living in a 1 ppm or a 0.2 ppm F area will have an approximately equal F intake of 5-10 micrograms per day, in spite of great differences in F intake among the nursing mothers.
Urinary concentrations of protein, albumin, beta 2-microglobulin, alpha-amino nitrogen, and creatinine were determined in forty-one full-term infants on seven occasions up to six months of age. Except for beta 2-microglobulin the concentrations were highest on the first day, followed by a rapid decrease to a constant level within two weeks. Protein diminished approximately seven-fold, albumin twenty-fold, alpha-amino nitrogen three-fold and creatinine five-fold. By contrast, beta 2-microglobulin, a low molecular weight protein, first increased three-fold between day 1 and day 5, thereafter decreasing slowly 17-fold during the first three months of age. The data indicate that different kidney functions mature asynchronously.
Abstract. In a consecutive series of 2 815 newborn infants the triglyceride (TG) and cholesterol (CHOL) concentrations were determined in total cord serum and in high density lipoprotein (HDL) containing serum after precipitation of very low (VLDL) and low density lipo proteins (LDL) with heparin manganese chloride. The serum concentrations of TG and CHOL in VLDL+LDL were calculated as the differences between the concentrations in total serum and HDL. The serum concentration of TG totally, in VLDL+LDL and HDL were 0.48, 0.33 and 0.14 mmol/l, respectively, in boys and 0.47, 0.32 and 0.15 mmol/l in girls and of CHOL 1.75, 0.94 and 0.80 mmol/l in boys and 1.88, 1.00 and 0.87 mmol/l in girls. The concentrations of CHOL were significantly higher (p<0.001) in girls than in boys. The distributions of all lipid parameters were skewed to the right, that is towards higher values. Lipoprotein electrophoresis in agarose gel was performed on all serum samples. Patterns compatible with hyperbeta and/or hyperprebeta lipoproteinaemia were observed but no cbylomicrons, broad beta, late prebeta or sinking prebeta lipoprotein bands. The skew distributions of TG and CHOL may be due to primary of secondary hyperlipidaemias.
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