Spectrophotometric Characteristics of Bilirubin

Lee, Kwang-Sun; Gartner, Lawrence M.

doi:10.1203/00006450-197609000-00004

Cited by 67 publications

(46 citation statements)

References 30 publications

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“…Our own data in vitro would appear to partially confirm the findings of Glauser; however, recent information suggests that the spectrophotometric characteristics of "dissolved" bilirubin are highly variable and that it may exist in solution as a finely dispersed colloid, as a flocculant, or as oxidation products (6,24). Our bilirubin solutions were made at molar ratios of less than 1.0 with respect to albumin and in a manner designed to maximize the existence of bilirubin in the albumin-bound state.…”

Section: Discussionsupporting

confidence: 72%

“…The clinical application of this phenomenon has been widely used as phototherapy in the treatment of neonatal hyperbilirubinemia. Investigations designed to delineate the effective wavelengths have employed broad spectrum light sources and have indicated that irradiance with light of wavelengths of 425-475 nm is maximally effective both in vitro (2,7,8,10,13,25,31) and in vivo (1,11,17,24,29,33,36). But one study performed in vitro with a relatively narrow spectral source suggested wavelengths at 490 nm might also be efficacious (10).…”

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confidence: 99%

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The in Vitro and in Vivo Photoreactivity of Bilirubin: I. Laser-Defined Wavelength Dependence

1983

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SummaryMonochromatic light was provided by a continuous wave Argon ion laser. We chose to study the in vitro effects of light at 457.9, 465.8, 476.5, 488.0, 501.7, and 514.5 nm as representative of a reasonably evenly spaced samplig across the blue-green spectrum. The in vivo experiments were conducted at 457.9, 476.5, 488.0, and 514.5 nm.In vitro light at 488.0 nm appeared to be more effective than the others studied.After 24 h of irradiance, the in vivo decline in serum bilirubin concentration produced by light at 488.0 nm was one-and-one-half, two, and four times as effective as light at 457.9, 476.5 and 514.5 nm, respectively. By 48 h of exposure, the declines produced by light at 457.9 nm and 488.0 nm are significantly superior to that at 476.5 nm and 514.5 nm, but they do not differ from one another.The photon-induced chemical alteration of bilirubin has been demonstrated by various light sources both in vitro and in vivo. The clinical application of this phenomenon has been widely used as phototherapy in the treatment of neonatal hyperbilirubinemia. Investigations designed to delineate the effective wavelengths have employed broad spectrum light sources and have indicated that irradiance with light of wavelengths of 425-475 nm is maximally effective both in vitro (2,7,8,10, 13,25,31) and in vivo (1,11,17,24,29,33,36). But one study performed in vitro with a relatively narrow spectral source suggested wavelengths at 490 nm might also be efficacious (10). More recently, Lilien et al. (27) have performed experiments that also suggest that wavelengths of light beyond the 425475 nm range are efficacious in vitro.Radiant energies within the 400-500 nm range exhibit potential for inducing damage to tissues. Light from standard fluorescent lamps causes breaks in DNA strands in vitro (3, 35) and increases sister chromatid exchanges and other chromosomal alterations in cultured cells (4,18,21,23,32,35,37). An increased frequency of sister chromatid exchange has been reported in some infants after phototherapy (12). Although we know of no reports regarding any increase in sister chromatid exchange in vivo in response to monochromatic light, the occurrence seems likely; thus, the widespread use of phototherapy has generated concern regarding the potential for long-term mutagenic and carcinogenic effects. Inasmuch as most published data suggest that the offending wavelengths are principally in the ultraviolet range, some recent work has implicated light of wavelengths exceeding 300 nm (9) and, indeed, some alterations appear to occur maximally in response to wavelengths of light between 420-500 nrn (35). Although the magnitude of these latter risks has not been quantitated as they may relate to the clinical setting, it seems desirable to more precisely define the most efficacious wavelengths for the photoalteration of bilirubin that results in its enhanced excretion. This is particularly needed in the design of future phototherapy instruments to be used in the management of neonatal hyperbilirubinemia. Preliminary po...

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Section: Discussionsupporting

confidence: 72%

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confidence: 99%

The in Vitro and in Vivo Photoreactivity of Bilirubin: I. Laser-Defined Wavelength Dependence

1983

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“…At B F levels above saturation, self-aggregation of UCB diacid must occur, progressing through three stages (7,(27)(28)(29). Oligomers of UCB diacid appear just above saturation; although they are too small to precipitate, they can dissociate reversibly and serve as a reservoir to replenish UCB monomers removed by cells.…”

Section: Discussionmentioning

confidence: 99%

Reassessment of the Unbound Concentrations of Unconjugated Bilirubin in Relation to Neurotoxicity In Vitro

2003

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“…they fall within the absorption band. For instance, the green line is equally effective even in the saline solution at pH 10 where the absorption maximum is shifted from 460 to 430 nm (4).…”

Section: 9mentioning

confidence: 99%

Laser Photolysis of Bilirubin

Sbrana¹,

Migliorini

Vecchi

et al. 1981

Pediatr Res

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Summarylengths are in the 400-470 nm range and in the region below 340Photodegradation of birubii in v i m has been investigated by using monochromatic light supplied by an argon ion laser selecting the 457.9,488.0 and 514.5 nm wavelengths.Bilirubin was examined in chloroform, in aqueous solutions and in human serum under different experimental conditions of concentration, laser power and time of irradiance. Photodecomposition was followed by optical density measurements on the absorp tion maximum of the electronic band at 460 nm.The rate of degradation of bilirubin was found to be only slightly affected by the wavelength of the exciting lines provided they fall within the absorption band. In particular it was shown that any wavelength, A, is equally effective if the corresponding absorbance, AA, exceeds a minimum value of 5-108. In the aqueous solutions, light with X > 470 nm has been found to be largely effective in the photodegradation of bilirubin in vitro. SpeculationThe results of bilirubin degradation by wavelengths longer than 470 nm in vitro suggest the use of green light in the clinical procedure in order to reduce damages to the tissues which can be caused when higher frequency radiations are employed.

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Spectrophotometric Characteristics of Bilirubin

Cited by 67 publications

References 30 publications

The in Vitro and in Vivo Photoreactivity of Bilirubin: I. Laser-Defined Wavelength Dependence

The in Vitro and in Vivo Photoreactivity of Bilirubin: I. Laser-Defined Wavelength Dependence

Reassessment of the Unbound Concentrations of Unconjugated Bilirubin in Relation to Neurotoxicity In Vitro

Laser Photolysis of Bilirubin

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