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

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          Abstract

          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.

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          Most cited references39

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          Circadian rhythms from flies to human.

          In this era of jet travel, our body 'remembers' the previous time zone, such that when we travel, our sleep wake pattern, mental alertness, eating habits and many other physiological processes temporarily suffer the consequences of time displacement until we adjust to the new time zone. Although the existence of a circadian clock in humans had been postulated for decades, an understanding of the molecular mechanisms has required the full complement of research tools. To gain the initial insights into circadian mechanisms, researchers turned to genetically tractable model organisms such as Drosophila.
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            HIF1 and oxygen sensing in the brain.

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              • Abstract: found
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              Putative melatonin receptors in a human biological clock.

              In vitro autoradiography with 125I-labeled melatonin was used to examine melatonin binding sites in human hypothalamus. Specific 125I-labeled melatonin binding was localized to the suprachiasmatic nuclei, the site of a putative biological clock, and was not apparent in other hypothalamic regions. Specific 125I-labeled melatonin binding was consistently found in the suprachiasmatic nuclei of hypothalami from adults and fetuses. Densitometric analysis of competition experiments with varying concentrations of melatonin showed monophasic competition curves, with comparable half-maximal inhibition values for the suprachiasmatic nuclei of adults (150 picomolar) and fetuses (110 picomolar). Micromolar concentrations of the melatonin agonist 6-chloromelatonin completely inhibited specific 125I-labeled melatonin binding, whereas the same concentrations of serotonin and norepinephrine caused only a partial reduction in specific binding. The results suggest that putative melatonin receptors are located in a human biological clock.
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                Author and article information

                Journal
                J Circadian Rhythms
                Journal of Circadian Rhythms
                BioMed Central (London )
                1740-3391
                2006
                11 September 2006
                : 4
                : 11
                Affiliations
                [1 ]Clinical Research Institute and Department of Pediatrics, National Hospital Organization, Miechuo Medical Center, 2158-5 Hisai Myojin Cho, Tsu City, Mie 514, Japan
                [2 ]Department of Developmental Clinical Psychology, Institute for Education, Mukogawa Women's University, 6-46 Ikebiraki Cho, Nishinomiya City, Hyogo 633, Japan
                [3 ]Department of Pediatrics and Developmental Science, Mie University Graduate School of Medicine, 174-2 Edobashi, Tsu City, Mie 514, Japan
                Article
                1740-3391-4-11
                10.1186/1740-3391-4-11
                1574348
                16961937
                4c1fc138-9f4f-430b-a334-0d4ac14ea8e9
                Copyright © 2006 ara et al; licensee BioMed Central Ltd.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 17 May 2006
                : 11 September 2006
                Categories
                Research

                Cell biology
                Cell biology

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