Factors Affecting Fluorescence Analysis of Diagnostically Important Urinary Metabolites—Influence of Mixture Composition

Abstract

The fluorescent analysis of multicomponent biological materials is very difficult. To model a proper system to characterize their quality is therefore indispensable. Influence of mixture composition was studied in a mixture of three naturally occurring diagnostically important urine metabolites: indoxyl sulfate, 5-hydroxyindole-3-acetic acid, and 3-methoxy-4-hydroxymandelic acid. Relationships between these compounds were monitored by measurement of synchronous fluorescence spectrum matrix. The fluorescence emission of 3-methoxy-4-hydroxymandelic acid when combined with indoxyl sulfate, or even with 5-hydroxyindole-3-acetic acid, was utilized for the excitation of indoxyl sulfate or 5-hydroxyindole-3-acetic acid, resulting in an increase in their fluorescence and in a decrease in 3-methoxy-4-hydroxymandelic acid fluorescence intensity.

The use of native fluorescence analysis of synovial fluid in the diagnosis of medial compartment disease in medium- and large-breed dogs

“…The presence of blood in the synovial fluid also did not affect its autofluorescence in the excitation wavelength range of 200-350 nm. Synovial fluid may contain many molecules potentially responsible for its autofluorescence, including various proteins, lipids, or small molecules derived from aromatic amino acids (e.g., 5-hydroxyindoleactic acid, 5-hydroxytryptamine, indoxyl sulfate, 15 or dopamine 12 ).The presence of the aromatic amino acids tyrosine and tryptophan is primarily responsible for protein native fluorescence. The fluorescence of a protein containing tyrosine is not dependent on the environment, in contrast to the fluorescence of proteins containing tryptophan.…”

“…If it is accepted that other components are involved in the fluorescence of the synovial fluid in response to the position of the excitation/ emission maximum, we can also consider other molecules with native fluorescence (e.g., a fluorescent aromatic amino acid derivative with a built-in indole ring, such as 5-hydroxyindoleacetic acid, 5-hydroxytryptamine, or indoxyl sulfate with a proven presence in synovial fluid; Table 4). 15 In addition to fluorescent molecules, the total native fluorescence of synovial fluid can be influenced by many other metabolites and factors. The intra-articular environment of an OA joint is more hypoxic and acidic than a healthy joint.…”

“…If it is accepted that other components are involved in the fluorescence of the synovial fluid in response to the position of the excitation/emission maximum, we can also consider other molecules with native fluorescence (e.g., a fluorescent aromatic amino acid derivative with a built-in indole ring, such as 5-hydroxyindoleacetic acid, 5-hydroxytryptamine, or indoxyl sulfate with a proven presence in synovial fluid; Table 4). 15…”

Organic Single-Component Enantiomers with High Phase Transition Temperatures and Dielectric Switching Properties

“…To gain a deeper understanding of the differences in the induced structural phase transitions of organic cation pairs, the molecular orbitals and energy levels of the crystal structures were investigated based on density functional theory (DFT). , The HOMO–LUMO gap is often used to reveal the stability of molecules because the HOMO–LUMO of the molecule has the properties of an electron donor and an electron acceptor, respectively. , Therefore, these two orbitals are the easiest to interact with and play an important role in the chemical reaction process . As shown in Figure , the charge densities of the HOMO states of 1-R and 1-S are highly delocalized on the N and O atoms in the compounds, while the LUMO states are mainly located on the C atoms.…”

Strong Dependence between Tryptophan-Related Fluorescence of Urine and Malignant Melanoma

“…The optical properties of the biological system obtained by fluorescence analysis reflect some of the physicochemical properties of the metabolites. Urine is a multicomponent mixture of different fluorophores and nonfluorescent metabolites [ 1 , 2 , 3 , 4 ].…”