In vitro production of bilirubin photoisomers by light irradiation using neoBLUE.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Okada
Hitoshi
H
Department of Pediatrics, Kangawa University, Kangawa, Japan. syounika@med.kagawa-u.ac.jp
Abe
Tae
T
Etoh
Yoko
Y
Yoshino
Shuji
S
Kato
Ikuko
I
Iwaki
Takuma
T
Okubo
Kensuke
K
Yasuda
Saneyuki
S
Kawada
Kou
K
Kusaka
Takashi
T
Namba
Masanori
M
Nishida
Tomoko
T
Imai
Tadashi
T
Isobe
Kenichi
K
Itoh
Susumu
S
D001663:Bilirubin / Q000031:analogs & derivatives / Q000096:biosynthesis* / Q000528:radiation effects; D002851:Chromatography, High Pressure Liquid; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D006932:Hyperbilirubinemia / Q000097:blood / Q000628:therapy; D007231:Infant, Newborn; D007536:Isomerism; D008027:Light; D010789:Phototherapy / Q000379:methods*
C041079:cyclobilirubin; D001663:Bilirubin