Effects of bilirubin photoisomers on the measurement of direct bilirubin by the bilirubin oxidase method

Author(s):  
Hitoshi Okada ◽  
Kou Kawada ◽  
Susumu Itoh ◽  
Miyo Ozaki ◽  
Isami Kakutani ◽  
...  

Background We occasionally encounter increases in direct bilirubin value on reanalysis of the surplus serum collected in the past from a neonate with indirect hyperbilirubinemia. But the details of this phenomenon are unclear. We evaluated the change of direct bilirubin and the relation of bilirubin photoisomer of the serum exposed to room light. Methods Surplus serum samples from neonates with indirect hyperbilirubinemia were exposed to room light for 24 h. The bilirubin fraction assay of samples was performed by the bilirubin oxidase method (Nescauto and Aqua-auto Kainos reagent) and high-performance liquid chromatography. Results Direct bilirubin increased significantly from 0.61 to 2.36 mg/dL. The respective ratios of bilirubin photoisomers before and after exposure were as follows: cyclobilirubin (0.007 to 0.29) and (EZ)-bilirubin (0.018 to 0.041) increased significantly, (ZZ)-bilirubin decreased 0.84 to 0.55 significantly. The difference of the cyclobilirubin concentration was most closely associated with those of the direct bilirubin concentration. Conclusion Direct bilirubin value was increased after exposure to the room light, and increase in direct bilirubin was significantly correlated by cyclobilirubin increase in the serum samples from neonates with indirect hyperbilirubinemia.

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 321
Author(s):  
Maria Orfanoudaki ◽  
Anja Hartmann ◽  
Julia Mayr ◽  
Félix L. Figueroa ◽  
Julia Vega ◽  
...  

This study presents the validation of a high-performance liquid chromatography diode array detector (HPLC-DAD) method for the determination of different mycosporine-like amino acids (MAAs) in the red alga Bostrychia scorpioides. The investigated MAAs, named bostrychines, have only been found in this specific species so far. The developed HPLC-DAD method was successfully applied for the quantification of the major MAAs in Bostrychia scorpioides extracts, collected from four different countries in Europe showing only minor differences between the investigated samples. In the past, several Bostrychia spp. have been reported to include cryptic species, and in some cases such as B. calliptera, B. simpliciuscula, and B. moritziana, the polyphyly was supported by differences in their MAA composition. The uniformity in the MAA composition of the investigated B. scorpioides samples is in agreement with the reported monophyly of this Bostrychia sp.


Author(s):  
Shohei Kawamoto ◽  
Kosuke Koyano ◽  
Miyo Ozaki ◽  
Takeshi Arai ◽  
Takashi Iwase ◽  
...  

Background Direct-reacting bilirubin concentrations measured using vanadate chemical oxidation method do not exactly match the conjugated bilirubin concentration. One of the causes is the effect of bilirubin photoisomers. However, the quantitative evaluation of the effects of these photoisomers has not been sufficiently conducted. In particular, the influence of bilirubin configurational isomers on direct bilirubin is the most critical factor. Methods Sixteen residual serum samples were used. For quantitative analysis based on the change in direct bilirubin and bilirubin configurational isomer, samples were irradiated via blue light-emitting diodes to suppress the production of bilirubin structural isomers. Total bilirubin and direct bilirubin concentrations were measured using the vanadate chemical oxidation method. Concentrations of 4Z,15Z-bilirubin IXα and its photoisomers were measured using high-performance liquid chromatography. The sum of 4Z,15E-bilirubin IXα and 4E,15Z-bilirubin IXα was notated as bilirubin configurational isomer, and the differences between the measured values of the irradiated and non-irradiated samples were calculated and notated as ΔDB and ΔBCI. Results In non-irradiated and irradiated samples, total bilirubin and direct bilirubin concentrations were 10.73 mg/dL with significant a decrease to 10.60 mg/dL and 0.69 mg/dL with a significant increase to 0.78 mg/dL, while bilirubin configurational isomer values were 1.00 mg/dL and 1.52 mg/dL, respectively. The linear regression equation revealed a significant positive correlation of Y = 0.187X−0.006 between ΔDB (Y) and ΔBCI (X). Conclusion Applying the vanadate chemical oxidation method affected approximately 19% of the bilirubin configurational isomer concentration for direct bilirubin. Extreme caution is necessary when interpreting the measured values of samples indicative of unconjugated hyperbilirubinaemia.


Author(s):  
Hitoshi Okada ◽  
Susumu Itoh ◽  
Shohei Kawamoto ◽  
Miyo Ozaki ◽  
Takashi Kusaka

Objective Investigation of the reactivity of fractions of bilirubin photoisomers with the vanadic acid oxidation method. Methods Bilirubin photoisomers were prepared by irradiating a bilirubin/human serum albumin solution with blue light emitting diode. Direct bilirubin and bilirubin fractions were measured using the vanadic acid oxidation method and high-performance liquid chromatography in the sample before and after irradiation. Results Direct bilirubin was increased in the solution containing bilirubin photoisomers. ( EE)-/( EZ) -cyclobilirubin-IXα and ( ZE)-/( EZ)-bilirubin-IXα completely disappeared after the addition of vanadic acid. Conclusion Bilirubin photoisomers reacted as direct bilirubin in the vanadic acid oxidation method.


1992 ◽  
Vol 262 (2) ◽  
pp. G351-G358
Author(s):  
R. Zhang ◽  
S. Barnes ◽  
R. B. Diasio

Mechanisms responsible for the difference in the relative amounts of taurine- and glycine-conjugated bile acid N-acyl amidates (Tau/Gly ratio) are not fully understood. In the present study, the stability of taurine- and glycine-conjugated bile acid N-acyl amidates during intestinal transit and absorption was examined to investigate the contribution of intestinal deconjugation to the Tau/Gly ratio in rat bile. Radiolabeled chenodeoxycholic acid (CDC) and its N-acyl amidates with glycine (CDC-Gly) or taurine (CDC-Tau) were introduced into the lumen of the upper small intestine in the biliary fistula rats, and radioactive metabolites in bile, blood, urine, and tissues were identified and quantitated by high-performance liquid chromatography. Results indicated that 1) extensive deconjugation of CDC-Gly occurs during intestinal absorption; 2) CDC-Tau is recovered in bile largely intact; and 3) newly synthesized CDC-Tau and CDC-Gly are formed in a ratio of less than 2:1 after administration of [14C]-CDC. In summary, the present study demonstrates that resistance of taurine-conjugated bile acid N-acyl amidates to hydrolysis in the intestine, rather than a difference in synthesis of taurine- and glycine-conjugated N-acyl amidates in liver, may account for the high Tau/Gly ratio in rat bile.


2019 ◽  
Vol 18 (10) ◽  
pp. 2121-2137 ◽  
Author(s):  
Joshua W. Jeffs ◽  
Nilojan Jehanathan ◽  
Stephanie M. F. Thibert ◽  
Shadi Ferdosi ◽  
Linda Pham ◽  
...  

Exposure of blood plasma/serum (P/S) to thawed conditions (> −30 °C) can produce biomolecular changes that skew measurements of biomarkers within archived patient samples, potentially rendering them unfit for molecular analysis. Because freeze-thaw histories are often poorly documented, objective methods for assessing molecular fitness before analysis are needed. We report a 10-μl, dilute-and-shoot, intact-protein mass spectrometric assay of albumin proteoforms called “ΔS-Cys-Albumin” that quantifies cumulative exposure of archived P/S samples to thawed conditions. The relative abundance of S-cysteinylated (oxidized) albumin in P/S increases inexorably but to a maximum value under 100% when samples are exposed to temperatures > −30 °C. The difference in the relative abundance of S-cysteinylated albumin (S-Cys-Alb) before and after an intentional incubation period that drives this proteoform to its maximum level is denoted as ΔS-Cys-Albumin. ΔS-Cys-Albumin in fully expired samples is zero. The range (mean ± 95% CI) observed for ΔS-Cys-Albumin in fresh cardiac patient P/S (n = 97) was, for plasma 12–29% (20.9 ± 0.75%) and for serum 10–24% (15.5 ± 0.64%). The multireaction rate law that governs S-Cys-Alb formation in P/S was determined and shown to predict the rate of formation of S-Cys-Alb in plasma and serum samples—a step that enables back-calculation of the time at which unknown P/S specimens have been exposed to room temperature. A blind challenge demonstrated that ΔS-Cys-Albumin can detect exposure of groups (n = 6 each) of P/S samples to 23 °C for 2 h, 4 °C for 16 h, or −20 °C for 24 h—and exposure of individual specimens for modestly increased times. An unplanned case study of nominally pristine serum samples collected under NIH-sponsorship demonstrated that empirical evidence is required to ensure accurate knowledge of archived P/S biospecimen storage history.


2005 ◽  
Vol 823 (2) ◽  
pp. 184-188 ◽  
Author(s):  
Andrew J. Mannes ◽  
Dorothy Cimino Brown ◽  
Jason Keller ◽  
Lauren Cordes ◽  
Roderic G. Eckenhoff ◽  
...  

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