Outdoor environment, ozone, radionuclide-associated aerosols and incidences of infantile eczema in Minsk, Belarus.

BACKGROUND: The early occurrence of atopic dermatitis in infants may be influenced by urban air pollution. OBJECTIVE: The aim of this study was to determine the relationship between incidences of infantile eczema in children under 2 years of age and urban outdoor environmental factors. METHODS: A 11-year population-based study was conducted in retrospective design. The age/gender-adjusted incidence rates of infantile eczema were determined using the data of outpatient visits. We analysed 1965 cases with atopic dermatitis including infantile eczema in relation to the annual means of outdoor monitoring data from 2005 through 2015 in Minsk. Logistic regression and principal component analysis were performed to determine association between the annual means of air pollutants, meteorological variables and incidences of infantile eczema. RESULTS: Higher mean annual carbon monoxide, ammonia, formaldehyde, lead, particulate matter and ground-level ozone were associated with high incidence rates of infantile eczema both in boys and girls. Higher nitrogen dioxide was associated with high incidence rates of infantile eczema in girls 1-2 years of age and boys 0-2 years of age. There were identified by principal component analysis five combinations of pollutants and meteorological factors. High incidence rates of infantile eczema were associated with the combinations contained higher levels of air pollutants and ultraviolet index, or lower ß-activity of the radionuclide-associated aerosols. The higher phenol and formaldehyde levels the higher incidence rates of infantile eczema were observed among boys 0-1 years of age and girls 1-2 years of age. The higher total column ozone with lower lead level was associated with low incidence rates of infantile eczema among boys and girls 1-2 years of age. CONCLUSION: Urban outdoor air pollutants and their combination with meteorological conditions may impact onset of infantile eczema in both genders.

Developmental and hormonal regulation of thermosensitive neuron potential activity in rat brain.

To understand the involvement of thyroid hormone on the postnatal development of hypothalamic thermosensitive neurons, we focused on the analysis of thermosensitive neuronal activity in the preoptic and anterior hypothalamic (PO/AH) regions of developing rats with and without hypothyroidism. In euthyroid rats, the distribution of thermosensitive neurons in PO/AH showed that in 3-week-old rats (46 neurons tested), 19.5% were warm-sensitive and 80.5% were nonsensitive. In 5- to 12-week-old euthyroid rats (122 neurons), 33.6% were warm-sensitive and 66.4% were nonsensitive. In 5- to 12-week-old hypothyroid rats (108 neurons), however, 18.5% were warm-sensitive and 81.5% were nonsensitive. Temperature thresholds of warm-sensitive neurons were lower in 12-week-old euthyroid rats (36.4+/-0.2 degrees C, n = 15, p<0.01,) than in 3-week-old and in 5-week-old euthyroid rats (38.5+/-0.5 degrees C, n = 9 and 38.0+/-0.3 degrees C, n = 15, respectively). The temperature thresholds of warm-sensitive neurons in 12-week-old hypothyroid rats (39.5+/-0.3 degrees C, n = 8) were similar to that of warm-sensitive neurons of 3-week-old raats (euthyroid and hypothyroid). In contrast, there was no difference in the thresholds of warm-sensitive neurons between hypothyroid and euthyroid rats at the age of 3-5 weeks. In conclusion, monitoring the thermosensitive neuronal tissue activity demonstrated the evidence that thyroid hormone regulates the maturation of warm-sensitive hypothalamic neurons in developing rat brain by electrophysiological analysis.