Tomoko Nishida

Kagawa University, Japan

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Publications (15)29.83 Total impact

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    ABSTRACT: BACKGROUND: Anemia of prematurity commonly occurs in infants with very low birth weight; blood transfusion is an important treatment. However, there is no clear evidence to support the criteria currently widely used, based on blood hemoglobin (bHb) and hematocrit indices. Previous studies showed that overtransfusion or a low threshold for transfusion could induce complications or neurologic sequelae, respectively. We hypothesized that a cerebral hemodynamic index may provide an appropriate criterion for determining the need for transfusion in anemic preterm infants. STUDY DESIGN AND METHODS: We used near-infrared time-resolved spectroscopy to measure cerebral hemoglobin oxygen saturation (ScO(2) ) and cerebral blood volume (CBV) before and after transfusion in 19 infants (24 measurements) with anemia of prematurity. The median gestational age was 27 weeks 0 days, median birth weight was 751 g, and median postconceptual age at transfusion was 30 weeks 4 days. RESULTS: bHb levels before and after transfusion (mean ± SD) were 9.3 ± 1.4 and 13.7 ± 1.3 g/dL, respectively. After transfusion, CBV significantly decreased from 2.63 ± 0.60 to 2.13 ± 0.26 mL/100 g of brain, and ScO(2) significantly increased from 72.8 ± 4.3% to 74.7 ± 4.2%. CONCLUSION: After transfusion, CBV changes were significantly greater with low compared to high pretransfusion Hb levels. This reflected the physiologic response to severe anemia in premature infants, which is to increase CBV and decrease ScO(2) . Therefore, CBV and ScO(2) may be useful markers for determining the need for transfusion in very-low-birth-weight infants.
    Transfusion 11/2012; · 3.53 Impact Factor
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    ABSTRACT: Low-frequency oscillations in cerebral blood flow that are suggestive of resting-state brain activity have recently been reported, but no study on the development of resting-state brain activity in preterm infants has been performed. The objective of this study was to measure the cerebral blood flow oscillations, which are assumed to represent brain function in the resting state, in preterm and term infants of the same postconceptional age. The subjects were 9 preterm infants who had reached full term (gestational age (GA): 23-34weeks, postconceptional age: 37-46weeks) and 10 term infants (GA: 37-40weeks, postconceptional age: 37-41weeks). Their changes in concentration of oxyhemoglobin ([oxyHb]) and deoxyhemoglobin ([deoxyHb]) were measured in the parieto-temporal region during quiet sleep using multi-channel near-infrared spectroscopy, and the power spectral densities (PSD) of the oscillations in the concentrations of these molecules were analyzed and compared. The preterm infants displayed a higher proportion of 0.06-0.10Hz low frequency oscillations of [oxyHb] and [deoxyHb] than the term infants, and the gestational age and the proportion of low frequency oscillations were inversely correlated. These findings suggest that resting-state cerebral blood flow oscillations differ between preterm and term infants, and that the development of circulatory regulation and nerve activity in preterm infants are influenced by the extrauterine environment.
    Brain & development 04/2012; · 1.74 Impact Factor
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    ABSTRACT: The purpose of this study was to examine developmental changes in visuocognitive function, particularly face recognition, in early infancy. In this study, we measured eye movement in healthy infants with a preference gaze problem, particularly eye movement between two face stimulations. We used the eye tracker system (Tobii1750, Tobii Technologies, Sweden) to measure eye movement in infants. Subjects were 17 3-month-old infants and 16 4-month-old infants. The subjects looked two types of face stimulation (upright face/scrambled face) at the same time and we measured their visual behavior (preference/looking/eye movement). Our results showed that 4-month-old infants looked at an upright face longer than 3-month infants, and exploratory behavior while comparing two face stimulations significantly increased. In this study, 4-month-old infants showed a preference towards an upright face. The numbers of eye movements between two face stimuli significantly increased in 4-month-old infants. These results suggest that eye movements may be an important index in face cognitive function during early infancy.
    Brain & development 02/2012; 34(9):719-22. · 1.74 Impact Factor
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    ABSTRACT: The objective of this study was to confirm physiological reactions in the breast and brain in mothers during breastfeeding and collect basic objective data, aiming at effective support for breastfeeding. Ten healthy women who were exclusively breastfeeding their babies participated in this study. Changes in the concentration of oxygenated Hb (oxyHb) and deoxygenated Hb in the breasts and frontal cortex of these women during breastfeeding lactation were measured using double-channel near-infrared spectroscopy (NIRS). Changes were measured in three conditions: (1) in both breasts; (2) the ipsilateral breast and frontal cortex; and (3) the contralateral breast and frontal cortex. OxyHb and total Hb (totalHb) levels in the bilateral breasts decreased significantly after the onset of breastfeeding in comparison with prebreastfeeding levels. These two values repeatedly increased and decreased thereafter. In the frontal cortex, regardless of which breast was involved, oxyHb and totalHb levels increased significantly in comparison with prebreastfeeding levels. Similar hemodynamic changes occurred simultaneously in the bilateral breasts during breastfeeding regardless of the feeding or nonfeeding side. Hemodynamic changes were also noted in the frontal cortex, but the reactions in the breast and prefrontal cortex were different and not synchronous, confirming that the physiological circulatory dynamics during breastfeeding vary among organs.
    Pediatric Research 06/2011; 70(4):400-5. · 2.67 Impact Factor
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    ABSTRACT: A case of cerebellar tumour is described in a 6 year old boy. It consists of two distinct areas, one consisting of tumour similar to medulloblastoma and the other of mesenchymal appearance in which cross striated muscle fibres are seen. Tumours of this type seem to form a small but separate entity, for which it is recommended that the name medullomyoblastoma be retained.
    Pediatrics International 06/2011; 53(3):399-402. · 0.88 Impact Factor
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    ABSTRACT: Multichannel near-infrared spectroscopy (MNIRS) was used for the functional imaging of the sensorimotor cortex of newborn infants during passive knee and elbow movement under sedated sleep. Contralateral knee and elbow movement caused a marked increase in the concentration of oxyhemoglobin ([oxyHb]) from the baseline values at site within the sensorimotor area in all infants. During ipsilateral knee and elbow movement, [oxyHb] showed smaller changes, equivalent to 64 ± 23 and 66 ± 28% of the changes that occurred with contralateral stimulation, respectively. The mean times corresponding to maximal changes in [oxyHb] were 16.1 ± 3.3 s for contralateral knee movement and 17.9 ± 5.7 s for contralateral elbow movement. No significant difference was noted between the mean latencies showing the maximal changes in [oxyHb] between contralateral and ipsilateral movement. There was a significant difference in the area and degree of response between the contralateral and ipsilateral movement. MNIRS could be a useful tool to understand the pathophysiology of the developing brain and monitor cortical responses in various clinical situations.
    Pediatric Research 01/2011; 69(5 Pt 1):430-5. · 2.67 Impact Factor
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    ABSTRACT: Adenine phosphoribosyltransferase deficiency is a disorder in which 2,8-dihydroxyadenine (2,8-DHA) crystalluria is caused by a congenital deficiency in the enzyme adenine phosphoribosyltransferase (APRT). In most cases, APRT deficiency is caused by autosomal recessive inheritance of a homozygote of the mutant gene APRT*Q0 or APRT*J, but there are also some cases in which the disorder is caused by the compound heterozygote APRT*Q0 and APRT*J. In the patients described here, brown round crystals were found in their urinary sediment. Crystalluria was the first sign of APRT deficiency, thereafter confirmed by genetic screening for APRT*/Q0 and APRT*. We performed genetic screening for APRT*Q0 and APRT*J in two families and diagnosed three cases of APRT*Q0 /APRT*J compound heterozygote-type APRT deficiency. Genetic screening for APRT*Q0 and APRT*J of family members is effective for early diagnosis and early treatment for family members.
    Pediatric Nephrology 06/2010; 25(6):1173-6. · 2.94 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the hypothesis that cerebral hemoglobin (Hb) oxygenation is related to phosphorylation potential during primary and secondary cerebral energy failure in newborn infants who have experienced birth asphyxia. We subjected newborn piglets to severe transient cerebral hypoxic-ischemia followed by resuscitation and examined cerebral energy metabolism by 31P-magnetic resonance spectroscopy and evaluated changes in cerebral Hb oxygen saturation (ScO2) using full-spectrum near-infrared spectroscopy before, during, and up to 54 h after the hypoxic-ischemic insult. ScO2 was significantly decreased during the hypoxic-ischemic insult compared with baseline values. During secondary energy failure, piglets were separated based on the relationship between the ratio of phosphocreatine to inorganic phosphate and ScO2; those with a negative correlation were less injured than those with a positive correlation. These results indicate that changes in ScO2 as measured by near-infrared spectroscopy are related to phosphorylation potential during secondary energy failure in asphyxiated infants.
    Pediatric Research 12/2008; 65(3):317-22. · 2.67 Impact Factor
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    ABSTRACT: The purpose of the present study was to measure changes in blood volume and the oxygenation state of breast tissue during breastfeeding with the use of near-infrared time-resolved spectroscopy (TRS) as a noninvasive method. Forty breastfeeding mothers were divided into 2 groups in which measurements were made in the contralateral breast (group A) and in the ipsilateral breast (group B). The tissue concentrations of oxyhemoglobin, deoxyhemoglobin, and total hemoglobin and the hemoglobin oxygen saturation were measured in the breast by using TRS during a breastfeed. In both groups A and B, the values of all parameters decreased significantly after the start of breastfeeding compared with the pre-breastfeeding values. The values of all parameters fluctuated cyclically after the beginning of the breastfeed. Time-resolved spectroscopy is an effective noninvasive method for investigating the hemodynamics of the breast during breastfeeding.
    Journal of Human Lactation 10/2008; 24(4):415-21. · 1.64 Impact Factor
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    ABSTRACT: Using optical topography, changes in the cerebral oxygenation were compared in the parieto-temporal lobe of preterm and term infants of equal postconceptional age in response to verbal stimulation. Eight preterm infants of gestational age 23-34 weeks were studied at postconceptional term age (38-46 weeks). Ten term infants were studied at 2-11 days after birth. Twenty-four-channel near-infrared optical topography (NIOT) was used to measure changes in concentration of oxyhemoglobin ([oxyHb]), deoxyhemoglobin ([deoxyHb]) and total hemoglobin ([totalHb]) in the bilateral temporal cortices. Verbal stimulation was provided by a recording of a Japanese fairy tale. The latency in response to verbal stimulation was significantly shorter in the preterm infants than in the term infants. This time is thought to reflect brain development, particularly the development of the neuro-vascular coupling mechanisms in the cerebral cortex. The present results indicate that the number of days after birth is more closely related to development of auditory system and neuro-vascular coupling than is postconceptional age. Thus, this suggests that early extrauterine environment affects the cortical responses to verbal stimulation in preterm infants.
    Neuroscience Letters 09/2008; 443(1):23-6. · 2.03 Impact Factor
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    ABSTRACT: The light-emitting diode is used as one of the new light sources for phototherapy. NeoBLUE (Atom Medical, Tokyo, Japan) incorporates blue light-emitting diodes for the treatment of neonatal hyperbilirubinemia. The authors compared the in vitro efficacy of neoBLUE with conventional phototherapy devices. The three light devices used included neoBLUE and two conventional phototherapy devices with six blue-white (BW) or six green (GR) fluorescent tubes. A bilirubin/human serum albumin solution (15 mg/dL) in 200 x 300 mm elliptical bag was irradiated with each three light device. The average light intensity of neoBLUE, BW and GR was 22.5, 10.2 and 2.6 microW/cm(2) per nm, respectively, for the irradiated area. Bilirubin photoisomers and native bilirubin were measured by high-performance liquid chromatography. In neoBLUE, BW and GR, the respective production rate of cyclobilirubin was 6.0, 3.7 and 3.9 x 10(-2) mg/dL/min, and the respective (4Z, 15E)-bilirubin/(4Z, 15Z)-bilirubin ratio after irradiation was 0.44, 0.33 and 0.12; the (4Z, 15Z)-bilirubin reduction rate at 20 min after irradiation was 60, 68 and 82%, respectively. The reduction rate of (4Z, 15Z)-bilirubin correlated with the (4Z, 15E)-bilirubin/(4Z, 15Z)-bilirubin ratio. Phototherapy using the neoBLUE under high level may be clinically more effective than therapy using the conventional light source from the results of the production rate of cyclobilirubin.
    Pediatrics International 07/2007; 49(3):318-21. · 0.88 Impact Factor
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    ABSTRACT: Near-infrared spectroscopy has been used for measurement of changes in cerebral Hb concentrations in infants to study cerebral oxygenation and hemodynamics. In this study, measurements by time-resolved spectroscopy (TRS) were performed in 22 neonates to estimate the values of light absorption coefficient and reduced scattering coefficient (mu'(s)), cerebral Hb oxygen saturation (SCO2), cerebral blood volume (CBV), and differential pathlength factor (DPF), and the relationships between postconceptional age and mu'(s), SCO2, CBV, and DPF were investigated. A portable three-wavelength TRS system with a probe attached to the head of the neonate was used. The mean mu'(s) values at 761, 795, and 835 nm in neonates were estimated to be (mean +/- SD) 6.46 +/- 1.21, 5.90 +/- 1.15 and 6.40 +/- 1.16/cm, respectively. There was a significant positive relationship between postconceptional age and mu'(s) at those three wavelengths. The mean SCO2 value was calculated to be 70.0 +/- 4.6%, and postconceptional age and SCO2 showed a negative linear relationship. The mean value of CBV was 2.31 +/- 0.56 mL/100 g. There was a significant positive relationship between postconceptional age and CBV. The mean DPF values at 761, 795, and 835 nm were estimated to be 4.58 +/- 0.41, 4.64 +/- 0.46, and 4.31 +/- 0.42, respectively. There was no relationship between postconceptional age and DPF at those three wavelengths. The results demonstrated that our near-infrared TRS method can be used to monitor mu'(s), SCO2, CBV, and DPF in the neonatal brain at the bedside in an intensive care unit.
    Pediatric Research 10/2005; 58(3):568-73. · 2.67 Impact Factor
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    ABSTRACT: Phototherapy has been a standard treatment for neonatal hyperbilirubinemia for more than 40 years, but it has remained sub-optimal. To clarify the developmental changes in parameters of (4E, 15Z)-cyclobilirubin ((EZ)-C) elimination in order to obtain basic data for establishing optimal phototherapy. Blood samples were taken at regular intervals after stopping phototherapy, and bilirubin fractions were analyzed by high-performance liquid chromatography. The subjects were 46 infants with hyperbilirubinemia who underwent phototherapy. The gestational age and birth weight of the subjects ranged from 25.0 to 41.0 weeks and from 656 to 3810 g, respectively, and the age at cessation of phototherapy was a median of 5 days. A kinetic model of (EZ)-C elimination was established, and the serum half-life of (EZ)-C was calculated on the basis of the determined model. Relationships of the half-life of (EZ)-C with birth weight and gestational age were investigated. Serum (EZ)-C elimination followed a first-order kinetic model in 43 infants and a zero-order kinetic model in three extremely low birth weight infants. The half-life of (EZ)-C calculated on the basis of a first-order elimination model in serum ranged from 68 to 274 min and showed weak negative correlations with birth weight and gestational age. Serum (EZ)-C excretion followed a first-order kinetic model in most of the neonates. The half-life of (EZ)-C becomes more prolonged in the very low birth weight infant and early gestational age.
    Early Human Development 08/2005; 81(7):619-22. · 2.02 Impact Factor
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    ABSTRACT: The developmental changes of the umbilical cortisol levels in neonates at gestational age of 23-41 weeks were studied and the effect of antenatal steroid administration on the umbilical cortisol levels were examined. Cortisol levels in the umbilical vein (UV) and the umbilical artery (UA) were studied in 35 neonates at the gestational age (GA) of 23-41 weeks with or without antenatal administration of corticosteroids. Serum cortisol concentrations were measured by the high performance liquid chromatography method. The correlation between cortisol levels in UV and birthweight (BW) was weak and negative in premature infants. UV cortisol levels in the neonates with antenatal corticosteroid were lower than those in the neonates without antenatal corticosteroid, but the relation was not significant. The developmental changes of UV cortisol levels were the same as those in Murphy's study (spontaneous-onset labor). The cortisol levels in UV and UA had a significantly positive correlation and both had almost equal concentrations. There were no correlations between cortisol levels in UV and placental weight, Apgar Score at 1 and 5 min. In the neonates whose birthweight was less than 2000 g without antenatal corticosteroid, there was a negative correlation between cortisol levels in UV and BW but there was no correlation between cortisol levels in UV and GA. That the neonates with antenatal corticosteroid would have a suppressed adrenocortical function after birth could not be proved.
    Pediatrics International 03/2005; 47(1):60-3. · 0.88 Impact Factor
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    ABSTRACT: The clinical effect of phototherapy for neonatal hyperbilirubinemia is based on the production and elimination of cyclobilirubin. Generally, the clinical effect of light sources is estimated by the reduction in the total serum bilirubin level. One procedure with less invasiveness than blood collecting is urine collection. Whether the effectiveness of light sources used for phototherapy could be assessed using measurements of bilirubin photoisomers in urine was studied. This study was a retrospective analysis of 38 term infants with hyperbilirubinemia who underwent phototherapy. Bilirubin fractions in serum and urine before and 24 h after the phototherapy were measured by high-performance liquid chromatography. The light sources used for the phototherapy were blue-white light (n = 11), Biliblanket plus high output (n = 13) or green light (n = 14). The relationships between serum and urine bilirubin photoisomers after phototherapy and whether the levels of urine bilirubin photoisomer are affected by the light sources with different wavelength characteristic were analyzed. There was no correlation between serum (ZE)-bilirubin and urine configurational isomers, but a weak positive correlation between serum (EZ)-cyclobilirubin and urine structural isomers after phototherapy. Although serum (ZE)-bilirubin levels depended on the wavelength characteristic of each light source during phototherapy, the urine configurational isomer levels did not depend on it. The increase in serum (EZ)-cyclobilirubin levels and the urine structural isomer levels were mostly in agreement. The urine bilirubin structural isomers may be used to estimate the serum (EZ)-cyclobilirubin levels and to evaluate the clinical effects of light sources.
    Pediatrics International 01/2005; 46(6):640-4. · 0.88 Impact Factor

Publication Stats

75 Citations
29.83 Total Impact Points

Institutions

  • 2005–2011
    • Kagawa University
      • • Department of Pediatrics
      • • Faculty of Medicine
      Japan