A new class of bilirubin photoderivatives obtained in vitro and their possible formation in jaundiced infants

Garbagnati, Ersilia; Manitto, Paolo

doi:10.1016/s0022-3476(73)80329-4

Cited by 22 publications

(9 citation statements)

References 12 publications

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“…The following solutions were irradiated: (1) bilirubin in anhydrous chloroform (1.6 10-5M), (2) bilirubin in saline solution, pH 10 (1.4 10-5M), (3) bilirubin dissolved in a saline solution pH 10 containing 4% of human albumin (2.3 IO-~M). Human albumin was supplied by Immuno (Vienna, Austria).…”

Section: Methodsmentioning

confidence: 99%

“…The efficacy of light in reducing the concentration of bilirubin in the blood is well known and many studies have been performed in the last years either in vivo (1,3,7,12) or in vitro (2,6,10). However, treatment is still largely empiric and some questions arise concerning the most effective wavelengths, the intensity of the light, the time of irradiance, the bilirubin decomposition mechanism and the long-term biological effects.…”

Section: Speculationmentioning

confidence: 99%

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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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Section: Methodsmentioning

confidence: 99%

Section: Speculationmentioning

confidence: 99%

Laser Photolysis of Bilirubin

Sbrana¹,

Migliorini

Vecchi

et al. 1981

Pediatr Res

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“…The shape of the curve indicates that intermediate products with high optical density are not formed or are short-lived. Oxidation of bilirubin with hydrogen peroxide and peroxidase in this respect seems to be different from photooxidation, which proceeds through strongly colored intermediates (26)(27)(28). Monitoring of the optical density at 455 nm apparently is suitable for observing the progress of the enzymatic oxidation.…”

Section: Methodsmentioning

confidence: 99%

Competitive Binding of Bilirubin and Drugs to Human Serum Albumin Studied by Enzymatic Oxidation

Brodersen¹

1974

J. Clin. Invest.

167

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“…A possible explanation is a reaction of ethanol with the EZ/ZE isomers. Photochemical addition of alcohols to the exo-vinyl group of bilirubin has been reported previously by Garbagnati and Manitto (23). However, the data are not consistent with Manitto's overall mechanism which requires the reaction to be light induced and irreversible.…”

Section: Fig 2 'mentioning

confidence: 64%

Solvent effects on the photoisomerization of bilirubin

Sailofsky¹,

Brown²

1987

Can. J. Chem.

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. J. Chem. 65, 1908 (1987).Studies of the photolysis of bilirubin IX-a by absorbance difference (AD) spectroscopy show that in solvents which do not interfere with the intramolecular hydrogen bonding, e.g., CHCI3, EZIZE isomers and lumirubins are formed, with the former being predominant. The addition of ethanol to CHC13, either before or during photolysis, greatly changes the AD spectra, possibly because of a reaction of photoproducts with the ethanol or solvatochromism of the EZIZE isomers. Solvents which interfere with the intramolecular hydrogen bonding of bilirubin, e.g., DMSO, increase the importance of the photoreaction that forms lumirubins. The kinetics of product formation indicate that the lumirubins result from a photoreaction of EZIZE isomers. The addition of aqueous buffer to DMSO lowers the extent of photoisomerization and leads to AD spectra that resemble those obtained for the photolysis in CHCI3. The addition of human serum albumin (HSA), using stopped flow techniques, to aqueous buffer solution of bilirubin immediately after photolysis gives evidence that the HSA traps the EZIZE isomers and prevents their reversion. However, in the presence of HSA the predominant pathway for photoreaction of bilirubin to EZIZE isomers is by reaction of the bound bilirubin. The AD spectra are similar to those obtained for solvents that interfere with hydrogen bonding. B. M. SAILOFSKY et G. R. BROWN. Can. J. Chem. 65, 1908 (1987).Les Ctudes de spectroscopie par absorbance differentielle (AD) ont dkmontrC que la photolyse de la bilirubine-IXa poursuivie en milieux qui ne perturbent pas les liaisons hydrogttnes, tel que le chloroforme, produit principalement les isomkres EZIZE, ainsi que des lumirubines. L'addition d'ithanol, par exemple au chloroforme, soit avant ou aprks la photolyse transforme les spectres AD, peut-&tre a la suite d'une rCaction des photoproduits avec 1'Cthanol ou en raison du solvatochromisme des isomttres EZIZE. Par contre, la formation des lumirubines par photorCaction est favoriskc dans des solvants tel que le sulphoxyde dimCthylique, c'est-a-dire dans des solvants qui perturbent les liaisons hydrogttnes. Ainsi, les rksultats d'Ctudes de cinktique dCmontrent que les lumirubines sont formCes par la photortaction des isomttres EZIZE. L'addition de solutions tampons aqueuses au sulphoxyde dimkthylique diminue le degrk de photoisomCrisation et les spectres AD obtenus ressemblent a ceux obtenus aprtts la photolyse dans le chloroforme. L'addition de la skrum-albumine humaine (SAH), immkdiatement aprts la photolyse, a des solutions tampons aqueuses de bilirubine en utilisant des techniques d'additions simultankes, indique que la SAH capte les isomttres EZIZE et emp&che leur inversion. Cependant, la photorCduction de la bilirubine en isomttres EZIZE en prCsence de la SAH se poursuit principalement par rkaction des bilirubines likes. Les spectres AD obtenus sont semblables ii ceux obtenus dans des milieux cjui perturbent les liaisons hydrogttnes.

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A new class of bilirubin photoderivatives obtained in vitro and their possible formation in jaundiced infants

Cited by 22 publications

References 12 publications

Laser Photolysis of Bilirubin

Laser Photolysis of Bilirubin

Competitive Binding of Bilirubin and Drugs to Human Serum Albumin Studied by Enzymatic Oxidation

Solvent effects on the photoisomerization of bilirubin

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