Biomedical subjects

Masahiko Yonetani

Publications and source records attributed to Masahiko Yonetani.

5 recordsLinked to original sources

PubMed2003

Evaluation of change of cerebral circulation by SpO2 in preterm infants with apneic episodes using near infrared spectroscopy.

BACKGROUND: In the neonatal intensive care unit (NICU), hemodynamics in very low-birthweight infants are generally examined for oxygen saturation (SpO2), heart rate, respiration rate, and blood pressure. The present study examined how changes in cerebral circulation in preterm infants can be evaluated by the SpO2 monitoring method with near infrared spectroscopy (NIRS) to detect the cerebral circulation. METHODS: The study was conducted in 11 low-birthweight neonates with a mean weight of 1252 g (940-1948 g), mean post-conceptional age of 28.9 weeks (28-31 weeks) and in whom a total of 145 apneic episodes were examined. Changes in cerebral circulation at the apneic attack were evaluated by two parameters of Delta HbD ( micro mol/L) for reduction in cerebral oxygenation and Delta cHb (mL/100 g brain) for variation in cerebral blood volume using the near infrared spectroscopy (NIRS). RESULTS: There was a tendency for a reduction in cerebral oxygenation and a change in cerebral blood volume as SpO2 was reduced. In the event of apneic attacks where SpO2 was reduced to <85%, cerebral oxygen saturation was extensively reduced. In addition, cerebral blood volume was also greatly changed when the SpO2 was reduced to <85%, and changed further still when SpO2 was reduced again to < or =75%. CONCLUSION: Reduction in SpO2 (<85%) was suggested to be an effective indication to changes in cerebral circulation. In the case of apneic attacks where SpO2 was < or =85%, the cerebral circulation in preterm low-birthweight neonates was extensively changed and, therefore, attention should be paid to changes in the concentration of SpO2 when managing apnea of prematurity in NICU.

Apnea↗

PubMed2003

New transcutaneous jaundice device with two optical paths.

OBJECTIVES: To confirm the accuracy and precision of transcutaneous bilirubin (TcB) values measured by a new device with two optical paths (JM-103) and the value of total serum bilirubin (TSB) level in clinical units of measurement. METHODS: For comparison of the levels of accuracy and precision of JM-103 and the old device (JM-102), serum samples were collected from 77 Japanese infants in three different hospitals including 24 preterm infants and 53 term infants. Measurement of TcB by JM-103 and JM-102 were performed on the forehead of each infant within 30 min before or after blood sampling. RESULTS: The range of TSB was limited to 19.6 mg/dL and to 17 mg/dL for preterm infants. The correlation coefficients for all subjects (r = 0.94) and for term and preterm subjects between TcB measured by JM-103 and TSB was higher than that between TcB measured by JM-102 and TSB. The regression line in term infants between TcB measured by JM-103 and TcB was similar to that in preterm infants. The error distribution of TcB measured by JM-102 and TSB for all subjects (0.00 +/- 2.21) and for term and preterm subjects was larger than that of TcB measured by JM-103 and TSB (all subjects, 0.30 +/- 1.55).

Bilirubin↗

PubMed2003

Selective brain hypothermia protects against hypoxic-ischemic injury in newborn rats by reducing hydroxyl radical production.

We hypothesized that selective brain hypothermia (SBHT) decreases production of hydroxyl radicals (*OH) induced by hypoxia-ischemia (H-I) and reperfusion and attenuates neuronal damage in neonatal rat brain. Anesthetized 7-day-old rats were divided into a normothermia (NT) group (n=6) and a SBHT group (n=7) and subjected to 90-min H-I, followed by a 90-min recovery period. Brain temperature (BT) was regulated by a water-cooled metallic plate placed under the head. The BT of the SBHT group was set at 31.0+/-1.0 degrees C during the H-I and recovery period. Microdialysis and the salicylate-trapping method were used to detect *OH in the striatum. Neuronal damage was quantified by counting the surviving neurons at 120 hr after reperfusion. The NT group had significant increases in 2,3-dihydroxybenzoic acid (DHBA) (223+/-166%) and 2,5-DHBA (321+/-153%) above baseline levels. The increases in 2,3-DHBA (127+/-40%) and 2,5-DHBA (133+/-33%) were significantly lower (p < 0.01) in the SBHT group. The number of surviving neurons was decreased significantly in the NT group but not in the SBHT group. We conclude that SBHT reduces *OH production during H-I and reperfusion and has protective effects against neuronal damage.

Animals↗

PubMed2002

Effects of child seats on the cardiorespiratory function of newborns.

BACKGROUND: This study aims to determine the effect of differently positioned infant car seats on cardio-respiratory parameters in healthy full-term newborns. METHODS: We examined 15 healthy term newborns for respiratory compromise due to normal restraint in a recommended infant car seat. There are currently two types of car seats available in Japan: a chair-shaped car seat and a bed-shaped car seat. Using a sleep apnea recorder, we simultaneously monitored heart rate, percutaneous oxygen saturation, chest impedance and nasal airflow in infants placed in each of the car seats and also placed in the supine position on a nursery cot. Episodes of oxygen desaturation below 95% and longer than 10 s (mild desaturation) and below 90% longer and than 10 s (moderate desaturation) were evaluated over 30 min observation period. RESULTS: The amount of time infants spent in a sleep state was significantly longer in the car seats than it was on the cot (P = 0.0015 for bed-shaped, P = 0.0012 for chair-shaped) and there was no difference in this measure between the two types of car safety seats. Mean of oxygen saturation with the chair-shaped car seat (95.8%) was significantly lower than that with the bed-shaped car seat (98.8%) (P = 0.0008). Newborn infants laid on the cot showed no episodes of desaturation. Newborn infants placed in the chair-shaped car seat had significantly more episodes of mild desaturation (mean, 7.33 times in nine of 15 infants), whereas in the bed-shaped seat observed only once each in two infants (P = 0.008). Moderate desaturation was observed in four of 15 infants in the chair-shaped car seat, whereas not observed in the bed-shaped car seat (P = 0.068). CONCLUSION: The results suggest that prior to discharge the degree of oxygen desaturation that occurs when an infant is placed in a chair-style car seat should be checked.

Female↗

PubMed2002

Gly71Arg mutation of the bilirubin UDP-glucuronosyltransferase 1A1 gene is associated with neonatal hyperbilirubinemia in the Japanese population.

The serum bilirubin level of Japanese newborn infants in their first few days is significantly higher than that in Caucasian newborn infants, suggesting that there might be genetic risk factors for the development of neonatal hyperbilirubinemia in the Japanese population. Recently, it has been reported that a variant TATA box in the promoter region of the bilirubin UDP-glucuronosyltransferase 1 (UGT1A1) gene is associated with the development of neonatal hyperbilirubinemia. This finding led us to the idea that a mutation, glycine to arginine at codon 71 (G71R), in the coding region of the UGT1A1 gene can cause neonatal hyperbilirubinemia. In this study, we determined the genotypic distribution of the G71R mutation in 72 Japanese newborn infants: 23 infants with hyperbilirubinemia and 49 infants without hyperbilirubinemia. In the hyperbilirubinemia group, 15 of 23 newborn infants had the G71R mutation (3 homozygotes and 12 heterozygotes), whereas in the non-hyperbilirubinemia group 16 of 49 newborn infants had the G71R mutation (1 homozygote and 15 heterozygotes). Therefore, the G71R mutation was present significantly more frequently in the hyperbilirubinemia group than in the non-hyperbilirubinemia group. This finding strongly suggests that the presence of the G71R mutation contributes to the development of neonatal hyperbilirubinemia in the Japanese population.

Arginine↗