Emergence of physiological rhythmicity in term and preterm neonates in a neonatal intensive care unit

BACKGROUND: Biological rhythmicity, particularly circadian rhythmicity, is considered to be a key mechanism in the maintenance of physiological function. Very little is known, however, about biological rhythmicity pattern in preterm and term neonates in neonatal intensive care units (NICU). In this study, we investigated whether term and preterm neonates admitted to NICU exhibit biological rhythmicity during the neonatal period. METHODS: Twenty-four-hour continuous recording of four physiological variables (heart rate: HR recorded by electrocardiogram; pulse rate: PR recorded by pulse oxymetry; respiratory rate: RR; and oxygen saturation of pulse oxymetry: SpO(2)) was conducted on 187 neonates in NICU during 0–21 days of postnatal age (PNA). Rhythmicity was analyzed by spectral analysis (SPSS procedure Spectra). The Fisher test was performed to test the statistical significance of the cycles. The cycle with the largest peak of the periodogram intensities was determined as dominant cycle and confirmed by Fourier analysis. The amplitudes and amplitude indexes for each dominant cycle were calculated. RESULTS: Circadian cycles were observed among 23.8% neonates in HR, 20% in PR, 27.8% in RR and 16% in SpO(2 )in 0–3 days of PNA. Percentages of circadian cycles were the highest (40%) at <28 wks of gestational age (GA), decreasing with GA, and the lowest (14.3%) at >= 37 wks GA within 3 days of PNA in PR and were decreased in the later PNA. An increase of the amplitude with GA was observed in PR, and significant group differences were present in all periods. Amplitudes and amplitude indexes were positively correlated with postconceptional age (PCA) in PR (p < 0.001). Among clinical parameters, oxygen administration showed significant association (p < 0.05) with circadian rhythms of PR in the first 3 days of life. CONCLUSION: Whereas circadian rhythmicity in neonates may result from maternal influence, the increase of amplitude indexes in PR with PCA may be related to physiological maturity. Further studies are needed to elucidate the effect of oxygenation on physiological rhythmicity in neonates

CD3+ B-1a Cells as a Mediator of Disease Progression in Autoimmune-Prone Mice

B-1a cells are distinguishable from conventional B cells, which are designated B-2 cells, on the basis of their developmental origin, surface marker expression, and functions. In addition to the unique expression of the CD5 antigen, B-1a cells are characterized by the expression level of CD23. Although B-1a cells are considered to be independent of T cells and produce natural autoantibodies that induce the clinical manifestations of autoimmune diseases, there is much debate on the role of B-1a cells in the development of autoimmune diseases. We examined the involvement of B-1a cells in autoimmune-prone mice with the lpr gene. MRL/lpr and B6/lpr mice exhibited lupus and lymphoproliferative syndromes because of the massive accumulation of CD3+CD4-CD8-B220+ T cells. Interestingly, the B220+CD23-CD5+ (B-1a) cell population in the peripheral blood and peritoneal cavity increased with age and disease progression. Ninety percent of B-1a cells were CD3 positive (CD3+ B-1a cells) and did not produce tumor necrosis factor alpha, interferon gamma, or interleukin-10. To test the possible involvement of CD3+ B-1a cells in autoimmune disease, we tried to eliminate the peripheral cells by hypotonic shock through repeated intraperitoneal injections of distilled water. The fraction of peritoneal CD3+ B-1a cells decreased, and symptoms of the autoimmune disease were much milder in the distilled water-treated MRL/lpr mice. These results suggest that CD3+ B-1a cells could be mediators of disease progression in autoimmune-prone mice

NICU明暗環境の時間生物学的評価ツールと子どもに優しい成育環境基準の検討

application/pdfNICU入院児の成育環境を検討するために、照度環境調整前後の低出生体重児のすいみん行動観察を動画撮影と活動計を用いて、BrazeltonのState判定と生理的反応の特徴を分析した。照度の調整による明らかな変化は認めなかったが、授乳前後の入眠は、授乳から約15分頃前よりState1-2が増えてくることや、周産期医療センター4施設すべてで、米国小児科学会(AAP)基準値を10dB超えていた。全アラームを排除したとしても深夜の静かな時間帯で1.5dB程度の騒音低減効果しか得られなかった。目視によるState判定は個人差があり、観察力教科学習支援を目指し睡眠自動判定装置として画像分析手法を開発中である。In order to examine the growth environment of cacies in neonatal intensive care units, we observed the sleep behavior of loe-birth-weight babies before and after adjusting the illuminance. We recorded videos of the babies and assessed their state using the neonatal behavioral assessment scale. We also analyzed their physiological responses with a motion watch activity meter. Although no significant change was brought about by the adjustment in illumination intensity, state 1-2 increased by about 15 minutes after breastfeeding, and the sound pressure was 10 dB higher than the standard set by the American Academy of Pediatrics for perinatal centers. Stopping all alarms had only a marginal effect on reducing sound pressure by 1.5 dB in the quiet of midnight. Since the individual differences in visual state judgment led to inaccuracy, we are developing an image analysis method for automatic sleep evaluation equipment to enhance nurses' observation skills.2016年度～2019年度科学研究費補助金(基盤研究(B))研究成果報告書16H0327