In vitro and in vivo efficacy of new blue light emitting diode phototherapy compared to conventional halogen quartz phototherapy for neonatal jaundice

Visible light accelerates skin wound healing and alleviates scar formation in mice by adjusting STAT3 signaling

During the wound healing process, the activation of signal transducer and activator of transcription 3 (STAT3) is considered crucial for the migration and proliferation of epithelial cells, as well as for establishing the inflammatory environment. However, an excessive STAT3 activation aggravates scar formation. Here we show that 450 nm blue light and 630 nm red light can differentially regulate the phosphorylation of STAT3 (p-STAT3) and its downstream cytokines in keratinocytes. Further mechanistic studies reveal that red light promotes wound healing by activating the PI3 kinase p110 beta (PI3Kβ)/STAT3 signaling axis, while blue light inhibits p-STAT3 at the wound site by modulating cytochrome c-P450 (CYT-P450) activity and reactive oxygen species (ROS) generation. In a mouse scar model, skin wound healing can be significantly accelerated with red light followed by blue light to reduce scar formation. In summary, our study presents a potential strategy for regulating epithelial cell p-STAT3 through visible light to address skin scarring issues and elucidates the underlying mechanisms.

Making Locally Fabricated Phototherapy Devices Work Better

BACKGROUND

The efficiency of a phototherapy (PT) device is a function of the irradiance delivered by the device at the surface of the skin. Because cost limits the ability of health care facilities in low- and middle-income countries to procure commercial PT devices, efforts have gone into local fabrication of devices for use in health care facilities in Nigeria. Evaluation of such fabricated devices is yet to be conducted.

OBJECTIVE

To identify and document essential features of locally fabricated phototherapy (FPT) devices in use in Nigeria.

MATERIALS AND METHODS

A cross sectional survey of locally FPT devices available in health facilities providing newborn health care services was conducted as part of evaluating neonatal jaundice management services in Kaduna State. Each FPT was characterized with respect to mobility/portability, adjustability, lamp type, number and color of lamps used. The irradiance of each device was measured using Model 22 Olympic BiliMeter™ at the facility's traditional PT distance and also at a distance at which optimum irradiance is delivered by the device.

RESULTS

A total of 54 PT devices were in use. Thirty-two (59.3%) of these devices were locally fabricated while others were obtained from commercial sources. Of the fabricated devices 22/32 (68.8%) were non-adjustable while the remaining 10 devices were adjustable but with limited adjustability. Only 5/32 (15.6%) of the FPT devices used special blue fluorescent lamps. The majority, 68.8% (22/32) of the FPT devices used ordinary low-intensity blue lamps while the remaining 5/32 (15.6%) devices used white light fluorescent lamps. None of the devices used light emitting diodes as a PT light source. Only three fabricated devices offered irradiance (9.4, 13.6 and 33 µW/cm2/nm) at the facilities' traditional distances for PT.

CONCLUSIONS

FPT devices in use in Kaduna, functioned sub-optimally because of technically inadequate designs. The devices will need to be designed to especially enable adjustability to vary distance between device and patient's skin and the use of lamps which offer high irradiance.

Susceptibility of oral bacteria to antibacterial photodynamic therapy

Effective methods for managing the oral microbiome are necessary to ensure not only the oral but also the systemic health of a human body. The purpose of this study was to determine the sensitivity of four photosensitizers (PSs) to blue light in six representative oral bacterial species that cause intraoral diseases. The following six strains were investigated: Actinomyces israelii, Enterococcus faecium, Fusobacterium nucleatum, Lactobacillus gasseri, Streptococcus mutans, Veillonella parvula. PS stock solutions (1 mg/ml) were prepared by dissolving curcumin and protoporphyrin-IX in dimethyl sulfoxide, and resazurin and riboflavin in distilled water. The inoculation of 20 ml of a bacterial suspension cultured for 24 hours was mixed with 1,980 ml of each test solution, and then a light source was placed in front of the mixture. The irradiation wavelength was 405 nm and its applied energy was 25.3 J. The independent-samples t-test and one-way analysis of variance within groups were performed to compare the antibacterial effects in the four PSs. The antibacterial susceptibility when using different PSs and visible blue-light irradiation differed between the bacterial strains. Antibacterial photodynamic therapy that includes light exposure and PSs can be used to control the oral bacteria strains related to oral disease.

Visible Blue Light Therapy: Molecular Mechanisms and Therapeutic Opportunities

BACKGROUND

Visible light is absorbed by photoacceptors in pigmented and non-pigmented mammalian cells, activating signaling cascades and downstream mechanisms that lead to the modulation of cellular processes. Most studies have investigated the molecular mechanisms and therapeutic applications of UV and the red to near infrared regions of the visible spectrum. Considerably less effort has been dedicated to the blue, UV-free part of the spectrum.

OBJECTIVE

In this review, we discuss the current advances in the understanding of the molecular photoacceptors, signaling mechanisms, and corresponding therapeutic opportunities of blue light photoreception in non-visual mammalian cells in the context of inflammatory skin conditions.

METHODS

The literature was scanned for peer-reviewed articles focusing on the molecular mechanisms, cellular effects, and therapeutic applications of blue light.

RESULTS

At a molecular level, blue light is absorbed by flavins, porphyrins, nitrosated proteins, and opsins; inducing the generation of ROS, nitric oxide release, and the activation of G protein coupled signaling. Limited and contrasting results have been reported on the cellular effects of blue light induced signaling. Some investigations describe a regulation of proliferation and differentiation or a modulation of inflammatory parameters; others show growth inhibition and apoptosis. Regardless of the elusive underlying mechanism, clinical studies show that blue light is beneficial in the treatment of inflammatory skin conditions.

CONCLUSION

To strengthen the use of blue light for therapeutic purposes, further in depth studies are clearly needed with regard to its underlying molecular and cellular mechanisms, and their translation into clinical applications.

High-intensity light-emitting diode vs fluorescent tubes for intensive phototherapy in neonates

BACKGROUND

Special blue fluorescent tubes are recommended by the American Academy of Pediatrics (AAP) as the most effective light source for lowering serum bilirubin. A high-intensity light-emitting diode ('super LED') could render intensive phototherapy more effective than the above conventional methods. This study compared the efficacy and safety of a high-intensity light-emitting diode bed vs conventional intensive phototherapy with triple fluorescent tube units as a rescue treatment for severe unconjugated neonatal hyperbilirubinaemia.

METHOD

This was a randomised, prospective trial. Two hundred jaundiced neonates ≥ 35 weeks gestation who met the criteria for intensive phototherapy as per AAP guidelines were randomly assigned to be treated either with triple fluorescent tube units (group 1, n = 100) or a super LED bed (group 2, n = 100). The outcome was the avoidance of exchange transfusion by successful control of hyperbilirubinaemia.

RESULTS

Statistically significant higher success rates of intensive phototherapy were achieved among neonates treated with super LED (group 2) than in those treated conventionally (group 1) (87% vs 64%, P = 0.003). Significantly higher 'bilirubin decline' rates were reported in both haemolytic and non-haemolytic subgroups treated with the super LED bed compared with a similar sub-population in the conventionally treated group. Comparable numbers of neonates in both groups developed rebound jaundice (8% vs 10% of groups 1 and 2, respectively). Side-effects were mild in both groups, but higher rates of hyperthermia (12% vs 0%, P = 0.03), dehydration (8% vs 2%, P = 0.26) and skin rash (39% vs 1%, P = 0.002) were reported in the fluorescent tubes-treated group compared with the LED group.

CONCLUSIONS

Super LED is a safe rescue treatment for severe neonatal hyperbilirubinaemia, and its implementation may reduce the need for exchange transfusion.

Phototherapy with blue and green mixed-light is as effective against unconjugated jaundice as blue light and reduces oxidative stress in the Gunn rat model

OBJECTIVE

Phototherapy using blue light-emitting diodes (LED) is effective against neonatal jaundice. However, green light phototherapy also reduces unconjugated jaundice. We aimed to determine whether mixed blue and green light can relieve jaundice with minimal oxidative stress as effectively as either blue or green light alone in a rat model.

METHODS

Gunn rats were exposed to phototherapy with blue (420-520 nm), filtered blue (FB; 440-520 nm without<440-nm wavelengths, FB50 (half the irradiance of filtered blue), mixed (filtered 50% blue and 50% green), and green (490-590 nm) LED irradiation for 24h. The effects of phototherapy are expressed as ratios of serum total (TB) and unbound (UB) bilirubin before and after exposure to each LED. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) was measured by HPLC before and after exposure to each LED to determine photo-oxidative stress.

RESULTS

Values < 1.00 indicate effective phototherapy. The ratios of TB and UB were decreased to 0.85, 0.89, 1.07, 0.90, and 1.04, and 0.85, 0.94, 0.93, 0.89, and 1.09 after exposure to blue, filtered blue, FB50, and filtered blue mixed with green LED, respectively. In contrast, urinary 8-OHdG increased to 2.03, 1.25, 0.96, 1.36, 1.31, and 1.23 after exposure to blue, filtered blue, FB50, mixed, green LED, and control, indicating side-effects (> 1.00), respectively.

CONCLUSIONS

Blue plus green phototherapy is as effective as blue phototherapy and it attenuates irradiation-induced oxidative stress.

PRACTICE IMPLICATIONS

Combined blue and green spectra might be effective against neonatal hyperbilirubinemia.

LED versus daylight phototherapy at low irradiance in newborns ≥35 weeks of gestation: randomized controlled trial

OBJECTIVE

To compare the decline in TSB after 24 h of LED or fluorescent phototherapy from below in breastfed neonates ≥35 weeks of gestation.

METHODS

Seventy-four neonates treated with a 17-bulb blue LED were compared with 76 neonates treated with a 7-bulb daylight device in a rooming-in unit. Spectral irradiance was measured at 5 points on a 30 × 60 cm rectangle on the gel transparent mattress.

RESULTS

TSB of 14.0 ± 1.2 mg/dL at 64 ± 15 h after birth when starting phototherapy were similar in both groups. TSB declined by 0.16 ± 0.09 in the LED versus 0.16 ± 0.08 mg/dL/hour in the daylight group after 24 h of therapy (p = 0.87). Mean irradiance (μW/cm(2)/nm) was 10.5 ± 0.9 (32.5 at the central, 5.9 at the superior and 3.9 for the inferior points) in the LED versus 8.7 ± 0.6 (range, 8.3 to 9.8) in the daylight group (p < 0.001). Hypothermia (<36.0 °C) was more frequent in LED than in fluorescent (23% versus 9%; p = 0.02) group.

CONCLUSION

LED with heterogeneous irradiance was as effective as daylight phototherapy with homogeneous irradiance; however there is a greater need for rigorous control of the room temperature (NCT01340339).

Transdentinal cell photobiomodulation using different wavelengths

OBJECTIVE

The aim of this study was to investigate the effects of transdentinal irradiation with different light-emitting diode (LED) parameters on odontoblast-like cells (MDPC-23).

METHODS AND MATERIALS

Human dentin discs (0.2 mm thick) were obtained, and cells were seeded on their pulp surfaces with complete culture medium (Dulbecco modified Eagle medium). Discs were irradiated from the occlusal surfaces with LED at different wavelengths (450, 630, and 840 nm) and energy densities (0, 4, and 25 J/cm(2)). Cell viability (methyltetrazolium assay), alkaline phosphatase activity (ALP), total protein synthesis (TP), and cell morphology (scanning electron microscopy) were evaluated. Gene expression of collagen type I (Col-I) was analyzed by quantitative polymerase chain reaction (PCR). Data were analyzed by the Mann-Whitney test with a 5% significance level.

RESULTS

Higher cell viability (21.8%) occurred when the cells were irradiated with 630 nm LED at 25 J/cm(2). Concerning TP, no statistically significant difference was observed between irradiated and control groups. A significant increase in ALP activity was observed for all tested LED parameters, except for 450 nm at 4 J/cm(2). Quantitative PCR showed a higher expression of Col-I by the cells subjected to infrared LED irradiation at 4 J/cm(2). More attached cells were observed on dentin discs subjected to irradiation at 25 J/cm(2) than at 4 J/cm(2).

CONCLUSION

The infrared LED irradiation at an energy density of 4 J/cm(2) and red LED at an energy density of 25 J/cm(2) were the most effective parameters for transdentinal photobiomodulation of cultured odontoblast-like cells.

Photosensitive fluorescent dye contributes to phototoxicity and inflammatory responses of dye-doped silica NPs in cells and mice

Dye-doped fluorescent silica nanoparticles provide highly intense and photostable fluorescence signals. However, some dopant dye molecules are photosensitive. A widely-used photosensitive fluorescent dopant, RuBpy, was chosen to systematically investigate the phototoxicity of the dye-doped silica nanoparticles (NPs). We investigated cell viability, DNA damage, and Reactive Oxygen Species (ROS) levels in alveolar macrophages using the dye-doped NPs with or without irradiation. Our results showed that the RuBpy-doped silica NPs could induce significant amount of ROS, DNA damage, apoptosis and impaired proliferation in MH-S cells. In vivo studies in mice showed that RuBpy-doped silica NPs induced significant inflammatory cytokine production and lowered expression in signaling proteins such as ERK1/2 and NF-κB as well as increased lung injury determined by myeloperoxidase and lipid peroxidation. Strikingly, we also found that both RuBpy alone and NPs induced systemic signaling activation in the kidney compared to the liver and lung where showed highly selective signaling patterns, which is more pronounced than RuBpy-doped silica NPs. Moreover, we discovered a critical biomarker (e.g., HMGB1) for silica NPs-induced stress and toxicity and demonstrated differentially-regulated response patterns in various organs. Our results indicate for the first time that the RuBpy-doped silica NPs may impose less inflammatory responses but stronger thermotherapeutic effects on target cells in animals than naked NPs in a time- and dose-dependent manner.

Can biowarfare agents be defeated with light?

Biological warfare and bioterrorism is an unpleasant fact of 21st century life. Highly infectious and profoundly virulent diseases may be caused in combat personnel or in civilian populations by the appropriate dissemination of viruses, bacteria, spores, fungi, or toxins. Dissemination may be airborne, waterborne, or by contamination of food or surfaces. Countermeasures may be directed toward destroying or neutralizing the agents outside the body before infection has taken place, by destroying the agents once they have entered the body before the disease has fully developed, or by immunizing susceptible populations against the effects. A range of light-based technologies may have a role to play in biodefense countermeasures. Germicidal UV (UVC) is exceptionally active in destroying a wide range of viruses and microbial cells, and recent data suggests that UVC has high selectivity over host mammalian cells and tissues. Two UVA mediated approaches may also have roles to play; one where UVA is combined with titanium dioxide nanoparticles in a process called photocatalysis, and a second where UVA is combined with psoralens (PUVA) to produce "killed but metabolically active" microbial cells that may be particularly suitable for vaccines. Many microbial cells are surprisingly sensitive to blue light alone, and blue light can effectively destroy bacteria, fungi, and Bacillus spores and can treat wound infections. The combination of photosensitizing dyes such as porphyrins or phenothiaziniums and red light is called photodynamic therapy (PDT) or photoinactivation, and this approach cannot only kill bacteria, spores, and fungi, but also inactivate viruses and toxins. Many reports have highlighted the ability of PDT to treat infections and stimulate the host immune system. Finally pulsed (femtosecond) high power lasers have been used to inactivate pathogens with some degree of selectivity. We have pointed to some of the ways light-based technology may be used to defeat biological warfare in the future.

Prospective randomized controlled study comparing low-cost LED and conventional phototherapy for treatment of neonatal hyperbilirubinemia

Our objective was to carry out a prospective, randomized, single-blind study to evaluate whether light emitting diode (LED) phototherapy using a low-cost set of lights is as effective as conventional phototherapy in treating hyperbilirubinemia in neonates. The study included 45 pre-term neonates requiring phototherapy as per American Academy of Pediatrics guidelines; participants were randomized to receive phototherapy using LED-based lights, conventional fluorescent blue lights or conventional halogen lights. There were no statistically significant differences in the average bilirubin levels at the onset, at the maximum and at the end of treatment, nor in the duration of phototherapy treatment and the rate of decrease in bilirubin levels in the neonates receiving conventional fluorescent blue light, conventional halogen light and LED phototherapy. (Differences were considered significant at p < 0.05). The average rate of decrease of bilirubin levels was 0.047 ± 0.037 mg dl(-1) h(-1), 0.055 ± 0.056 mg dl(-1) h(-1) and 0.057 ± 0.045 mg dl(-1) h(-1) in the groups receiving conventional fluorescent blue light, conventional halogen light and LED phototherapy, respectively. The average duration of phototherapy treatment in the three groups was 108.8 ± 85.9 h, 92.8 ± 38.1 h, 110.4 ± 42.6 h, respectively. In this pilot study, LED phototherapy using a simple, low-cost set of lights was as effective as conventional phototherapy in the treatment of neonatal hyperbilirubinemia. LED phototherapy lights that deliver 30-40 µW cm(-2 )nm(-1) can be assembled in small quantities for <US$ 100 each using off-the-shelf parts; such lights may enable phototherapy to be safely and reliably delivered in low-resource settings.

Efficacy of light-emitting diode versus other light sources for treatment of neonatal hyperbilirubinemia: a systematic review and meta-analysis

Various light-emitting diode (LED) phototherapy devices have been trialled on the assumption of a more effective spectral distribution of the light emitted. We reviewed the current literature to determine whether LED is more effective than other types of phototherapy. Eligible studies were randomized controlled trials of LED versus other phototherapies. Studies were found to be of medium quality based on a components approach. Data were statistically aggregated within a very homogeneous population (term or late preterm neonates). Results appeared robust at sensitivity analysis. Five hundred and eleven neonates were included in the meta-analysis. LED and other phototherapy devices appeared to be equally effective in reducing total serum bilirubin (TSB) in term or late preterm neonates. The pooled mean TSB rate of decrease was 3.269 μmol/L/h (0.191 mg/dL/h) and 3.074 μmol/L/h (0.18 mg/dL/h) in the LED and conventional arms, respectively [average difference in TSB rate of decrease = 0.194 μmol/L/h (0.011 mg/dL/h) in favour of LED phototherapy; p = 0.378].

CONCLUSION

No significant difference in TSB rate of decrease was detected between LED and other types of phototherapy. Further randomized controlled trials are needed to ascertain whether LED phototherapy may be more effective when increasing the spectral power, or in certain selected subpopulations.

Light-emitting diode phototherapy for unconjugated hyperbilirubinaemia in neonates

BACKGROUND

Phototherapy is the mainstay of treatment of neonatal hyperbilirubinaemia. The commonly used light sources for providing phototherapy are special blue fluorescent tubes, compact fluorescent tubes and halogen spotlights. However, light emitting diodes (LEDs) as light sources with high luminous intensity, narrow wavelength band and higher delivered irradiance could make phototherapy more efficacious than the conventional phototherapy units.

OBJECTIVES

To evaluate the effect of LED phototherapy as compared to conventional phototherapy in decreasing serum total bilirubin levels and duration of treatment in neonates with unconjugated hyperbilirubinaemia.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library 2010, Issue 1), MEDLINE (1966 to April 30, 2010) and EMBASE (1988 to July 8, 2009). Handsearches of the proceedings of annual meetings of The European Society for Paediatric Research and The Society for Pediatric Research were conducted through 2010.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials were eligible for inclusion if they enrolled neonates (term and preterm) with unconjugated hyperbilirubinaemia and compared LED phototherapy with other light sources (fluorescent  tubes, compact fluorescent tubes, halogen spotlight; method of administration: conventional or fibreoptic).

DATA COLLECTION AND ANALYSIS

We used the standard methods of The Cochrane Collaboration and its Neonatal Review Group for data collection and analysis.

MAIN RESULTS

Six randomised controlled trials met the inclusion criteria for this review. Four studies compared LED and halogen light sources. Two studies compared LED and compact fluorescent light sources. The duration of phototherapy (six studies, 630 neonates) was comparable in LED and non-LED phototherapy groups (mean difference (hours) -0.43, 95% CI -1.91 to 1.05). The rate of decline of serum total bilirubin (STB) (four studies, 511 neonates) was also similar in the two groups (mean difference (mg/dL/hour) 0.01, 95% CI -0.02 to 0.04). Treatment failure, defined as the need of additional phototherapy or exchange blood transfusion (1 study, 272 neonates), was comparable (RR 1.83, 95% CI 0.47 to 7.17). Side effects of phototherapy such as hypothermia (RR 6.41, 95% CI 0.33 to 122.97), hyperthermia (RR 0.61, 95% CI 0.18 to 2.11) and skin rash (RR 1.83, 95% CI 0.17 to 19.96) were rare and occurred with similar frequency in the two groups.

AUTHORS' CONCLUSIONS

LED light source phototherapy is efficacious in bringing down levels of serum total bilirubin at rates that are similar to phototherapy with conventional (compact fluorescent lamp (CFL) or halogen) light sources. Further studies are warranted for evaluating efficacy of LED phototherapy in neonates with haemolytic jaundice or in the presence of severe hyperbilirubinaemia (STB ≥ 20 mg/dL).

Overhead is superior to underneath light-emitting diode phototherapy in the treatment of neonatal jaundice: a comparative study

AIM

To compare the efficacy of overhead and underneath light-emitting diode (LED) devices in the treatment of neonatal jaundice.

METHODS

We compared two LED phototherapy devices: the neoBLUE device, which provides overhead illumination, and the neoBLUE cozy device, which provides illumination from underneath the infant. The models we used had similar LED sources and provided similar light intensities (30 microW/cm(2)/nm). Infants with hyperbilirubinemia were assigned to one of two groups according to the phototherapy device used (group 1, overhead illumination, 181 infants; group 2, underneath illumination, 61 infants). Recorded variables included birthweight, gender, family history, aetiology of jaundice, total duration of phototherapy and total serum bilirubin (TSB) concentration at the initiation of phototherapy, at 12-hour intervals and just before the cessation of phototherapy. The rates of decrease in TSB concentration were calculated.

RESULTS

There were significant differences in the mean duration of phototherapy and in the rate of decrease in TSB concentration between the two groups. The mean duration of phototherapy in group 2 was higher than in group 1 (P= 0.037). The rate of decrease in TSB in group 1 was higher than in group 2 (P= 0.01).

CONCLUSION

These results suggest that when phototherapy is used in the treatment of neonatal jaundice, the direction from which the light is applied should be considered in addition to light source intensity.

Apoptosis in the small intestine of neonatal rat using blue light-emitting diode devices and conventional halogen-quartz devices in phototherapy

Phototherapy is the most frequently used treatment for the neonatal jaundice. However, recent papers report that phototherapy increased apoptosis in peripheral mononuclear leukocytes in vivo and in mouse lymphoma cell line in vitro. We have investigated the cytotoxicity of phototherapy on the small intestine of neonatal rat using conventional halogen-quartz device (conventional device) and blue light-emitting device (LED device) by measuring apoptotic cells. Four-day-old male Wistar rats were divided into three groups as follows: group 1, exposure to conventional device for 72 h; group 2, exposure to LED device for 72 h; and group 3, control (without phototherapy). After light exposure, the small intestine was examined for apoptosis. Apoptotic cells were detected by the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) assay, by immunohistochemistry for caspase-3 and by transmission electron microscopy. The proportion of positive cells by the TUNEL method in the epithelium of the small intestine was 6.2, 3.1 and 1.7% in the conventional device group, the LED device group and the control group, respectively. The apoptotic cells of the conventional device group is significantly higher than the LED device group (P < 0.01) and that of the LED device group was higher than that of the control group (P < 0.05). We suspected that phototherapy induced apoptosis in neonatal small intestine and the conventional device introduces more apoptosis than the LED device.

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.

CONCLUSION

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.