Related Experiment Video
Updated: Jan 11, 2026
05:03
Author Spotlight: Investigating Physiological Functions of Vitamin A Transporters Using HPLC-Based Vitamin A Profiling
Published on: December 27, 2024
1.6K
Bilirubin Photoisomers in Neonatal Jaundice
Dennis Lindqvist1, Magnus Hansson1,2, Mercy Thomas3,4
1Department of Clinical Chemistry, Karolinska University Hospital, 171 64 Stockholm, Sweden.
International Journal of Molecular Sciences
|November 13, 2025
Summary
Phototherapy converts bilirubin into excretable photoisomers for treating neonatal hyperbilirubinemia. New mass spectrometry methods improve understanding of these isomers, potentially optimizing treatment.
Area of Science:
- Biochemistry
- Neonatal Medicine
- Photochemistry
Background:
- Neonatal hyperbilirubinemia is common, with phototherapy as the standard treatment.
- Phototherapy converts bilirubin into more soluble photoisomers for excretion.
- Understanding bilirubin photoisomers is crucial but limited by biochemical complexity and methodology.
Purpose of the Study:
- To provide an updated review of bilirubin photoisomers.
- To discuss their chemistry, quantification, and clinical relevance.
- To explore future research directions for optimizing phototherapy.
Main Methods:
- Literature review of existing research on bilirubin photoisomers.
- Discussion of analytical techniques, particularly mass spectrometry.
- Analysis of the biochemical pathways of bilirubin photoisomerization.
Main Results:
- Bilirubin photoisomers are key to phototherapy's efficacy in reducing neonatal jaundice.
- Methodological challenges have previously limited comprehensive understanding.
- Advances in mass spectrometry allow for more accurate isomer quantification.
Conclusions:
- Improved knowledge of photoisomer formation and kinetics can refine phototherapy.
- Accurate measurement of isomers may offer better treatment efficacy indicators than total bilirubin.
- Further research is needed to fully elucidate the clinical significance of bilirubin photoisomers.
Related Concept Videos
02:52Stereoisomerism
13.8K
Isomerism in Complexes
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
13.8K
01:22Photoreceptors and Visual Pathways
8.7K
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category,...
8.7K
01:26Photochemical Electrocyclic Reactions: Stereochemistry
2.2K
The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
Selection Rules: Photochemical Activation
2.2K
02:32Stereoisomers
17.4K
On the basis of mirror symmetry, stereoisomers of an organic molecule can be further classified into diastereomers and enantiomers. Diastereomers are stereoisomers that are not mirror images of each other. Substituted alkenes, such as the cis and trans isomers of 2-butene, are diastereomers, as these molecules exhibit different spatial orientations of their constituent atoms, are not mirror images of each other, and do not interconvert. Here, the interconversion is suppressed due to...
17.4K
02:33Stereoisomerism of Cyclic Compounds
10.9K
In this lesson, we delve into the role of ring conformation and its stability, which determines the spatial arrangement and, consequently, the molecular symmetry and stereoisomerism of cyclic compounds. 1,2-Dimethylcyclohexane is used as a case study to evaluate the possible number of stereoisomers. Here, given the multiple (n = 2) chiral centers, there are 2n = 4 possible configurations that lack a plane of symmetry, as the ring skeleton exists in a non-planar chair conformation. In addition,...
10.9K
01:24Pharmacokinetics in Pediatric Patients: Drug Metabolism
182
In pediatric care, understanding the nuances of hepatic drug metabolism is crucial, as it significantly differs from that of adults. This divergence is primarily due to the developmental stage of drug-metabolizing enzymes, which affects how medications are processed in the body. In neonates, for instance, the activity of Phase I enzymes—critical for the initial breakdown of drugs—is markedly reduced, functioning at just 20–40% of the levels seen in adults. This reduction poses...
182