Bilirubin: Photophysical and photochemical properties, phototherapy, analytical methods of measurement. A short review.

Bilirubin, a yellow bile pigment, plays an important role in the body, being a potent antioxidant and having anti-inflammatory, immunomodulatory, cytoprotective, and neuroprotective functions. This makes bilirubin promising as a therapeutic and diagnostic agent in biomedicine. However, excess bilirubin is toxic and should be removed from the body.

Endogenous and Exogenous Antioxidants as Agents Preventing the Negative Effects of Contrast Media (Contrast-Induced Nephropathy).

The use of conventional contrast media for diagnostic purposes (in particular, Gd-containing and iodinated agents) causes a large number of complications, the most common of which is contrast-induced nephropathy. It has been shown that after exposure to contrast agents, oxidative stress often occurs in patients, especially in people suffering from various diseases. Antioxidants in the human body can diminish the pathological consequences of the use of contrast media by suppressing oxidative stress.

Spectral-Fluorescent Study of the Interaction of Cationic and Anionic Polymethine Dyes with Sodium Deoxycholate in Aqueous Solutions.

The noncovalent interaction of a number of cationic and anionic meso-substituted polymethine (carbocyanine) dyes with sodium deoxycholate (NaDC) as a biologically important surfactant was studied by spectral-fluorescent methods. The following dyes were studied: 3,3'-di(β-hydroxyethyl)-9-methylthiacarbocyanine-iodide (K1), 3,3'-di(β-hydroxyethyl)-5,5'-dimethoxy-9-ethylthiacarbocyanine iodide (K2), 3,3',9-trimethylthiacarbocyanine iodide (K3, Cyan 2), 3,3'-di(γ-sulfopropyl)-9-methylthiacarbocyanine-betaine (A1), and 3,3'-di(γ-sulfopropyl)-4,5,4',5'-dibenzo-9-ethylthiacarbocyanine-betaine (A2, DEC). Upon addition of increasing concentrations of NaDC, the absorption spectra of dyes K1-K3 in aqueous solutions exhibit changes due to the formation of dye aggregates and their subsequent decomposition into monomers.

Spectral-fluorescent study of the interaction of polymethine dye probes with biological surfactants - bile salts.

Spectral-fluorescent properties of polymethine dye probes anionic 3,3'-di(sulfopropyl)-4,5,4',5'-dibenzo-9-ethylthiacarbocyanine-betaine (DEC) and cationic 3,3',9-trimethylthiacarbocyanine iodide (Cyan 2) in the presence of biological surfactants, bile salts sodium cholate (NaC), sodium deoxycholate (NaDC) and sodium taurocholate (NaTC), as well as sodium dodecyl sulfate (SDS), have been studied in a wide range of surfactant concentrations. When a surfactant is introduced into a solution of DEC, changes of the spectral-fluorescent properties are observed due to decomposition of dye dimers into cis-monomers and cis-trans conversion of the resulting monomers. In the presence of SDS, both processes occur in parallel, caused by noncovalent interaction of dye monomers with micelles, and mainly occur near the critical micelle concentration (CMC).

Lutein and its oxidized forms in eye structures throughout prenatal human development.

The presence of carotenoids in the vitreous body, retina, lens, retinal pigment epithelium together with choroid (hereinafter RPE), and ciliary body and iris together with choroidal stroma (hereinafter CBI) was studied throughout the second trimester of prenatal development of the human eye. It has been found that the vitreous body, retina, and RPE contain lutein and its oxidized forms. Zeaxanthin was not found in the tissues studied.

Spectral-fluorescent study of the interaction of the polymethine dye probe Cyan 2 with chondroitin-4-sulfate.

The noncovalent interaction of the polymethine dye probe 3,3',9-trimethylthiacarbocyanine iodide (Cyan 2) with chondroitin-4-sulfate (C4S) in buffer solutions with different pH and in water in the absence of buffers has been studied by spectral-fluorescent methods. It has been shown that in all media studied, at relatively high concentrations, the dye is bound to C4S mainly as a monomer, which is accompanied by a steep rise of fluorescence (the intermediate formation of dye aggregates on the biopolymer is also observed). From the dependence of the fluorescence quantum yield on the concentration of C4S, the parameters of binding of the dye monomer to C4S were obtained: the effective binding constant K, the number of the monomeric C4S units n per one dye monomer bound to C4S, and the fluorescence quantum yield of the bound dye monomer Φ.

Characterization of the composition of the aqueous humor and the vitreous body of the eye of the frog Rana temporaria L.

This study aimed to analyze the aqueous humor (AH) and the vitreous body (VB) of the eye of the adult frog Rana temporaria L. as a representative species of amphibians, which lead a semi-terrestrial life. The presence of collagen, albumin, uric acid and electron donors was shown in both media; however, there are slight differences in their concentrations.

Use of a cyanine dye as a probe for albumin and collagen in the extracellular matrix.

The aim of this work was to develop a quick method for analysis of macromolecules of the extracellular matrix. Of great interest are soluble components of the extracellular matrix, in particular, carrier proteins, whose variation dynamics can characterize the studied tissue in its development, adult stage, and aging. We suggest the method of analysis of the extracellular matrix to reveal the presence of albumin and collagen by using an anionic cyanine dye as a spectral and fluorescence probe.