Neonatal screening for glucose-6-phosphate dehydrogenase deficiency fails to detect heterozygote females

We examined glucose-6-phosphate dehydrogenase (G6PD) deficiency in north-eastern Italian Caucasian neonates detected by neonatal screening, in order to measure the incidence of heterozygote females detected by neonatal screening, and to estimate the near-true total incidence. A total of 85,437 Caucasian neonates, born between January 2000 and December 2001, have been enclosed in the study. The total incidence of the disease, measured by fluorescent method, is 0.9‰; the total incidence, calculated by Hardy-Weinberg law, is 4.8‰. The frequency of missed females is 93% of total females expected with G6PD deficiency; most of them are very likely heterozygous females. The sensitivity of the fluorescent method might be not sufficient to detect all females. Since heterozygote females might develop the symptoms of G6PD deficiency later, these results suggest that the G6PD neonatal screening may not be helpful in preventing disease in female

Incomplete gastric metaplasia in children with insulin-dependent diabetes mellitus and celiac disease. An ultrastructural study

BACKGROUND: The association of insulin-dependent diabetes mellitus (IDDM) and celiac disease (CD) has been widely reported in children but the relationship between the two conditions is incompletely understood. Moreover, specific studies on intestinal biopsies of patients with the association of the two diseases are still lacking. METHODS: We studied the ultrastructure of the duodenal mucosa in 12 patients with both IDDM and CD. RESULTS: All patients had either total or partial atrophy of duodenal mucosa. In seven subjects, an accumulation of electrondense granules in the apical cytoplasm of groups of enterocytes was found. In four of them, a double population of granules existed (mean diameter: 400-800 nm and 100-200 nm respectively) showing a biphasic pattern. In the other three patients, only smaller granules (100- 200 nm) were found in the enterocytes. CONCLUSIONS: The present work suggests that patients with IDDM/CD may represent a subgroup in the context of the CD population. Intestinal biopsies of such individuals often show accumulation of electrondense granules in the apical cytoplasm of enterocytes that can be interpreted as incomplete gastric metaplasia

Evaluation of growth hormone bioactivity using the Nb2 cell bioassay in children with growth disorders

The Nb2 cell bioassay could be a useful tool for evaluating human growth hormone (hGH) bioactivity, but is not specific for hGH since it relies on the ability of the hormone to produce effects by cross-reacting with the lactogenic receptor on Nb2 cells. We studied the biological activity of both endogenous and exogenous hGH in short patients using the Nb2 bioassay after inhibiting the mitogenic effect of the other lactogenic hormone, that is human prolactin (hPRL), by adding a specific antibody against hPRL to each assay. The in vitro study showed a significant (p < 0.0001) increase in Nb2 cell proliferation when increasing concentrations of highly purified hGH were added to the cell culture. A complete inhibition of Nb2 cell replication was observed after adding a specific antibody against hGH. The in vivo study showed a significantly (p < 0.0001) lower hGH bioactivity (4.90 ± 0.28 ng/ml) evaluated during stimulation tests in 9 children with total idiopathic GH deficiency, mean age 9.25 ± 1.99 years, in comparison with that found in 11 short children with normal growth velocity, mean age 8.22 ± 1.41 years (12.25 ± 1.19 ng/ml). Likewise, serum GH levels measured by immunofluorometric assay IFMA in the same serum samples were significantly (p < 0.001) lower in the 9 GH-deficient (1.97 ± 0.37 ng/ml) than in the 11 short children (21.85 ± 2.71 ng/ml). Moreover, we evaluated GH concentrations using both IFMA and the Nb2 cell bioassay in serum samples collected from another 11 idiopathic GH-deficient children, mean age 10.71 ± 1.18 years, before and then, 6 and 24 hours following the 1st injection of r-hGH (0.1 IU/kg sc). Serum GH values measured by both IFMA and Nb2 bioassay significantly (p < 0.0001) increased 6 hours after r-hGH administration and decreased to reach basal levels after 24 hours. In conclusion, the Nb2 cell bioassay with minor modifications seems to provide a specific and sensitive assessment of hGH bioactivity

Postnatal variations of growth hormone bioactivity and of growth hormone dependent factors

Objective: To evaluate whether the low insulinlike growth factor I (IGF- I) levels that are observed in the neonate depend on the biological inactivity of the molecular forms of growth hormone (GH) or on the immaturity of the hepatic GH receptors during the early postnatal period. Materials and Methods: Serum samples were collected from 60 normal full-term neonates on day 5 and at 1 and 4 months of age to evaluate the GH concentrations by using both an immunofluorometric assay and Nb2 cell bioassay, as well as the GH- binding protein, IGF-1, and IGF-binding protein 3 values by radioimmunoassay. Results: Five-day-old neonates showed significantly higher (P<.001) mean±SEM GH levels that were measured by using the immunofluorometric assay (27.22±1.62 μg/L) and Nb2 cell bioassay (3.56±0.14 U/mL) compared with those levels in 11 prepubertal children who were studied as control subjects (1.26±0.28 μg/L and 0.74±0.08 U/mL, respectively). At 1 and 4 months of age, GH values that were measured by using both the immunofluorometric assay (9.15±089 and 2.58±0.32 μg/L, respectively) and Nb2 cell bioassay (2.52±0.11 and 1.71±0.15 U/mL, respectively) were decreased significantly (P<.001). In 5 day-old neonates, we observed significantly lower (P<.001) serum GH-binding protein (9.73%±0.42%), IGF-I (67.63±5.20 ng/mL), and IGF- binding protein 3 (1.46±0.17 mg/L) concentrations compared with those in the prepubertal children (30.74%±2.01%, 210±25 ng/mL, and 3.08±0.22 mg/L, respectively). At 1 month of age, serum GHbinding protein (16.00%±0.70%) and IGF-binding protein 3 (2.96±0.30 mg/L) values were increased significantly (P<.001), while IGF-I levels (72.55±7.6 ng/mL, P=.09) were not increased. Serum IGF-I values were increased significantly (P<.005) at 4 months of age (97.94±9.68 ng/mL). Conclusion: The interaction of bioactive molecular forms of GH with the increased hepatic GH receptors induces the rise in postnatal IGF-I levels in early infancy