EFFECT OF SEASON AND VITAMIN D SUPPLEMENTATION ON PLASMA CONCENTRATIONS OF 25-HYDROXYVITAMIN D IN NORWEGIAN INFANTS

ABSTRACT. Plasma concentrations of 25-hydroxyvitamin D (250HD) were determined in 81 vitamin D supplemented or unsupplemented infants at the end of winter. The values were compared with maternal levels and with concentrations found in 22 unsupplemented infants at the end of summer. The 250HD levels of the neonates were lower, but closely related to maternal values ( r =0.95, p <0.0005). Unsupplemented breast-fed infants had lower 250HD levels at 6 weeks than at 4 days (16±7 vs. 32±15 nmol/l, mean ±1 SD, p <0.0005). The mean 250HD level of vitamin D supplemented 6-12 months old infants was intermediate between those of the unsupplemented nursed groups and the unsupplemented children studied during summer (53±28 vs. 85±28 nmol/l, p <0.0005). Six weeks old infants who had received a milk formula containing 400 IU vitamin D₃ per liter had levels similar to the latter group (92±21 nmol/l). The data suggest that the vitamin D stores acquired during fetal life, or from ultraviolet light exposure during the summer, may be inadequate to maintain safe levels of 250HD throughout the winter, but that a daily supplement of 400 IU is adequate to establish concentrations in the summer range.     

PLASMA CONCENTRATIONS OF VITAMIN D METABOLITES IN A CASE OF RICKETS OF PREMATURITY

ABSTRACT. Rickets was diagnosed in an extremely low-birthweight infant 16 weeks after birth. She had a normal plasma concentration of 25-hydroxyvitamin D, a relatively low level of 24,25-dthy-droxyvitamin D, and a markedly elevated 1,25-dihydroxyvitamin D level compared with adult standards. The plasma concentrations of the vitamin D metabolites were, however, indistin-guishable from those of healthy preterm infants who received a similar diet of human milk and vitamins. The results indicate that rickets was not caused by vitamin D deficiency or by abnormal vitamin D metabolism, but by calcium and/or phosphate deficiency, and that the calcium and phosphorous content of human milk may be inappropriately low for very low-birthweight infants.     

EXCRETION OF BILE ACIDS IN EXTRAHEPATIC BILIARY ATRESIA AND INTRAHEPATIC CHOLESTASIS OF INFANCY

This series included 24 infants, 16 boys and 8 girls, who were admitted to hospital with the diagnosis of obstructive jaundice. Five of the infants were subsequently found to have extra-hepatic biliary atresia (BA) and the other 19 infants intrahepatic cholestasis of infancy (IHC). The infants were investigated given special attention to: the quantitative urinary excretion of cholic and chenodeoxycholic acids, the isotope excretion after intramuscular injection of cholic acid-24–¹⁴C, the nature of labelled urinary bile acids, the half-life and the pool size of cholic acid. At the first examination of the infants after admission the urinary excretion of cholic and chenodeoxycholic acids varied greatly between the patients. However, on comparing the values obtained in the two groups, it was found that there was virtually no difference between the mean daily values of cholic and chenodeoxycholic acids in urine, and the ratio cholic to chenodeoxycholic acid between the BA group and the IHC group. After the injection of isotopic cholic acid most of the isotope was recovered in the urine in all cases. In the infants with BA the faecal excretion of the isotope was low, being less than 3 per cent of the injected isotope. Out of the 19 infants with IHC the recovery of the injected isotope in faeces was also less than 3% in 11 infants. In 8 infants with IHC the faecal isotope excretion was significantly high to exclude extrahepatic biliary atresia. The first 24 hour urine specimen contained small amounts of unconjugated labelled cholic acid in all cases whereas in no case did the patients excrete unconjugated labelled cholic acid 48 hours after the injection of the isotope. No transformation of cholic acid was observed. There was no difference between the BA group and IHC group with regard to the percentage labelled glycine conjugates of total excreted urinary conjugates. Neither was there any difference between the two groups with regard to half-life and pool size of cholic acid. There was no difference with respect to the bile acid metabolism between infants with congenital CMV infection, decreased serum concentrations of alfal-antitrypsin and the other patients.     

EFFECT OF PORCINE CALCITONIN THERAPY ON VITAMIN D METABOLISM AND CLINICAL RESPONSE IN A PATIENT WITH OSTEOGENESIS IMPERFECTA

ABSTRACT. A 1 11/12-year-old girl with osteogenesis imperfecta was treated with porcine calcitonin. Eight bone fractures occurred in the previous 20 months before therapy, but none occurred during eight months of therapy. There was also a significant improvement in linear growth and radiographic bone density. This is the first study of the effect of calcitonin on vitamin D metabolism in a human. The high plasma levels of 1,25 dihydroxy-vitamin D (1,25-(OH)₂-D) and 24,25 dihydroxy-vitamin D (24,25-(OH)₂-D) before calcitonin therapy decreased after therapy. Plasma 25 hydroxy-vitamin D (25-OH-D) concentration, which normal in level before calcitonin therapy, was normal or slightly decreased during administration. It is concluded that calcitonin probably influences vitamin D metabolism in a patient with osteogenesis imperfecta.     

SERUM ALPHA-FETOPROTEIN LEVELS IN EXTRAHEPATIC BILIARY ATRESIA, IDIOPATHIC NEONATAL HEPATITIS AND ALPHA-1-ANTITRYPSIN DEFICIENCY (PiZ)

Abstract. Serum alpha-fetoprotein levels were measured using a sensitive radioimmunoassay in 77 infants presenting with persistent conjugated hyperbilirubinaemia. A broad range of alpha-fetoprotein concentrations occurred in both the 23 infants with extrahepatic biliary atresia and the 35 with idiopathic neonatal hepatitis but the 13 with alpha-1-antitrypsin deficiency had uniformly low levels. High alpha-fetoprotein concentrations (above 10 000 μg/I) favoured the diagnosis of neonatal hepatitis especially in the first ten weeks of life, but the overlap between neonatal hepatitis and extrahepatic biliary atresia was large and alpha-fetoprotein determination cannot be recommended as a reliable method for distinguishing the two conditions. Serial alpha-fetoprotein values showed no consistent relationship with standard liver function tests and gave no guide to prognosis. There was an association between alpha-fetoprotein production and needle biopsy evidence of hepatic giant cell transformation. The uniformly low alpha-fetoprotein levels in alpha-1-antitrypsin deficient infants with neonatal hepatitis is a new observation and possible mechanisms for disordered glycoprotein release are discussed.     

THE RENAL RESPONSE TO AN ORAL SALT AND FLUID LOAD IN CHILDREN WITH COARCTATION OF THE AORTA

The natriuretic effect of an oral salt load has been tested in 6 children before and after resection of coarctation of the aorta. Pre- and postoperative determinations of GFR and PAH clearances were also made. Preoperatively the natriuresis following the salt load was depressed, indicating enhanced tubular sodium reabsorption. The GFR was slightly elevated, the PAH clearance was normal and the filtration fraction was elevated. Postoperatively there was an increase in the natriuretic response and a fall in the filtration fraction. There was a significant inverse correlation between the filtration fraction and the urinary excretion of the salt load. The results suggest that coarctation of the aorta is associated with a shift in intrarenal vascular resistance and that this hemodynamic change will, by rise in the oncotic pressure of the peritubular capillaries, result in the enhancement of the tubular sodium reabsorption.     

THE COMPARISON OF ANTIBODY RESPONSE TO DIFFERENT HEPATITIS B VACCINES WITH AND WITHOUT pre-S2 ANTIGEN IN CHILDREN WITH CANCER

Children with cancer are at an increased risk of hepatitis B infection and chronic liver disease. Since hepatitis B vaccines containing pre-S2 antigen has been recently reported as being more efficient in providing immunization in healthy individuals, the authors compared antibody response to pre-S2-containing vaccine with no-pre-S2-containing hepatitis B vaccine, when given in double doses to 100 children receiving chemotherapy. Patients, aged 1 to 16 years with negative HBV serology, were vaccinated with 2 different types of HBV vaccines between 1997 and 1999. Group 1 received Gen Hevac B containing pre-S2 ( n = 41) in a dose of 20 &#119 g for patients younger than 10 years old and 40 &#119 g for older patients. Group 2 was vaccinated at the same dose with hepatitis B vaccines not containing pre-S2 antigen. All vaccinations were repeated at 0, 1, and 6 months. Serum samples were drawn for determination of anti-HBs titers at 1, 3, 6, and 8 months. After the third dose of vaccine, the seroconversion rate was 72% in group 1 and 62% in group 2. The anti-HBs levels were higher in the group receiving pre-S2-containing hepatitis B vaccine. However, the difference between groups was not statistically significant ( p > .05). The administration of pre-S2-containing hepatitis B vaccines may give a better seroconversion and higher antibody response to vaccination in children with cancer. But a further large-scale study is needed to confirm this finding.     

PRECIPITATING ANTIBODIES TO E. COLI O ANTIGENS: A SUGGESTED DIFFERENCE IN THE ANTIBODY RESPONSE OF INFANTS AND CHILDREN WITH FIRST AND RECURRENT ATTACKS OF PYELONEPHRITIS

The presence of precipitating antibodies to E. coli O antigens in consecutive serum samples from infants and children with pyelonephritis without obstructions in the urinary tract was studied using an immunodiffusion method. Precipitating antibodies were found in only five of 20 patients clinically diagnosed as having their first attack of pyelonephritis, but in all of 13 patients with a recurrent infection. Such antibodies were not found in any of 93 controls without symptoms or signs of urinary tract infection. The reason for the appearance of IgG precipitins to E. coli mainly in patients with recurrent pyelonephritis is discussed with regard to three possibilities: a secondary antibody response induced by the recurrent infection, an adjuvant effect of endotoxin remaining from an earlier infection and finally more severe infections causing stronger antigenic stimuli in patients with tendency toward recurrencies. The detection of precipitating antibodies to E. coli O antigens might be useful for early recognition of patients with recurrent pyelonephritis, who are at risk to develop progressive renal scarring.