Objective: To assess the age at which the circadian rhythm of melatonin begins. Methods: 55 children, divided into groups from the neonatal period to 24 months of life, were studied. Urine samples were taken from 28 newborn babies to measure 6-sulfatoxymelatonin (aMT6s). Salivary samples were collected from infants (27 cases), to measure melatonin (aMT). aMT was measured by RIA and aMT6s by ELISA using commercial kits. Changes in the levels of aMT6s and aMT were evaluated using the Friedman test and Wilcoxon matched pair test. Results: The group aged 27–41 days showed statistically significant differences in daily aMT6s and aMT concentrations. The highest values were always found between 24.00 and 8.00 h. This day/night difference persisted from 2–3 to 13–24 months of age. Conclusion: The data indicate that the circadian melatonin rhythm appears at the end of the neonatal period and persists thereafter.

The power absorption of Co-rich metallic glasses in the shape of ribbons and microwires has been measured in the microwave frequency range. The technique employed consists of replacing the dielectric of a coaxial transmission line by the amorphous sample to be measured. The ferromagnetic resonance frequency of the microwires has been obtained by analyzing the absorbed power as a function of an external magnetic field. From the evolution of this resonance frequency, the anisotropy field has been deduced and successfully compared to that obtained from low-frequency hysteresis loops.

The aims of this study were: (1) to investigate the evolution of the sleep pattern in preterm newborns during their first month of life; (2) to assess the influence of light-dark on the sleep pattern; and (3) to compare this pattern with that of full-term newborns. The population consisted of 60 healthy, preterm newborns and 63 full-term newborns, divided into four age groups, 1 week apart, throughout the first month of life. Preterm newborns were further divided into five groups according to conceptional (corrected) age. An observer took note every 30 min, for 24 h, of sleep or wakefulness in every case. The average sleeping time in preterm groups according to postnatal age remained unchanged during the first month of life: 17.57 h on day 1 and 17.15 h on day 28. When the preterm infants were re-grouped according to conceptional age, average daily sleep was 17.86 h at 32 weeks and 15.22 h at 37 weeks. The full-term newborns had an average daily sleep of 14.78 h on day 1 and 11.94 h on day 28, with a decrease throughout week 4 of life (p < 0.001). The decrease in daily sleeping time in the full-term groups, took place at the expense of the daylight span, where there was a decrease throughout the first month of life (p < 0.01). There were no differences in preterm newborns during the light and dark phases. A progressive synchronization of sleep to the light-dark was seen in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

A study on melatonin rhythm in children with generalized idiopathic epilepsy and simple fever is presented in this article. A population of 40 children was divided into 4 groups, namely, epilepsy, febrile seizure, and 2 control groups. Salivary melatonin was measured by means of radioimmunoassay. Friedman 2-way analysis of variance (ANOVA) and Wilcoxon tests were employed to assess the existence of melatonin rhythm. Comparison across groups was performed by means of ANOVA and Mann-Whitney tests. Higher melatonin levels were found at night, with a peak at 04:00 h in all groups. Significant diurnal rhythm was also detected for these levels. No significant overall differences between case and control groups were found for melatonin levels, though patients showed lower peak melatonin values than controls at 04:00 h with a significant difference in the febrile seizure group (10.70 vs 19.5 pg/mL respectively; P<.04). Our data support the presence of diurnal rhythm in blood melatonin concentrations in children with epileptic and febrile seizures. Comparison between case and control groups showed lower peak concentrations in the febrile seizure group with respect to healthy controls.

Data on cystic fibrosis deaths were drawn from the National Statistics Institute (Instituto Nacional de Estadística), which collects data from all death certificates in Spain. During the period 1981-2004, overall CF mortality in Spain decreased by an annual average of 4% in both sexes. A breakdown by age showed that patients under 15 years registered a declining and those over 15 years a rising mortality rate over the study period. Mean and median age at death from CF increased with time, from a median of 4.4 years (males) and 3.8 years (females) in 1981 to 20.1 years (males) and 17.7 years (females) in 2004. The results of this study show that, as in other Western countries, CF is no longer a major cause of death in childhood, and that the challenge now lies in caring for adults who suffer from this disease. The fact that our study was descriptive meant that the reasons for the decrease in CF mortality in Spain could not be identified. Other authors have shown that this decrease is associated with improved treatment for pulmonary complications, better nutritional control and lung transplants.