Spectrofluorometric Analysis of Autofluorescing Components of Crude Serum from a Rat Liver Model of Ischemia and Reperfusion

Short communications: Exploring temporal fluorescent changes in the composition of human semen stains

Semen traces are considered important pieces of evidence in forensic investigations, especially those involving sexsual offenses. Recently, our research group developed a fluorescence-based technique to accurately determine the age of semen traces. However, the specific compounds resonsible for the fluoresescent behaviour of ageing semens remain unknown. As such, in this exploratory study, the aim is to identify the components associated with the fluorescent behavior of ageing semen traces. In this investigation semen stains and various biofluorophores commonly found in body fluids were left to aged for 0, 2, 4, 7, 14 and 21 days. Subsequently, thin-layer chromatography (TLC) and ultra-performance liquid chromatography (UPLC) mass spectrometry were performed to identify the biofluorophores present in semen. Several contributors to the autofluorescence could be identified in semen stain, these include tryptophan, kynurenine, kynurenic acid, and norharman. The study sheds light on the.

Polymer-Based Terbium Complex as a Fluorescent Probe for Cancer Antigen 125 Detection: A Promising Tool for Early Diagnosis of Ovarian Cancer

A novel photoprobe, Tb-acetylacetone (Tb-ACAC) doped within a modified epoxy cellulose polymer immobilized with CA-125 monoclonal antibody, offers an accurate and highly selective method for early ovarian cancer (OC) diagnosis by detecting cancer antigen 125 (CA-125) in serum samples. This approach leverages quenching of the Tb-ACAC luminescence upon binding to CA-125. Characterization of the photoprobe film through UV-vis and fluorescence measurements confirmed the presence of Tb-ACAC within the polymer matrix. In aqueous solution (pH 6.8, λex = 365 nm), the characteristic emission band of Tb-ACAC at λem = 546.2 nm exhibited significant quenching upon CA-125 binding. This quenching effect enabled the sensitive and specific detection of CA-125 in diverse serum samples from OC patients, demonstrating the applicability, simplicity, and effectiveness of this novel approach.

Deconvolution of the fluorescence spectra measured through a needle probe to assess the functional state of the liver

OBJECTIVES

Currently, one of the most pressing issues for surgeons in the treatment of obstructive jaundice is the ability to assess the functional state of the liver and to detect and determine the degree of liver failure in a timely manner with simple and objective techniques. In this regard, the use of fluorescence spectroscopy method can be considered as one of the ways to improve the informativity of existing diagnostic algorithms in clinical practice and to introduce new diagnostic tools. Thus, the aim of the work was to study in vivo the functional state of liver parenchyma by the method of fluorescence spectroscopy implemented through a needle probe and assess the contribution of the main tissue fluorophores to reveal new diagnostic criteria.

MATERIALS AND METHODS

We compared data from 20 patients diagnosed with obstructive jaundice and 11 patients without this syndrome. Measurements were performed using a fluorescence spectroscopy method at excitation wavelengths of 365 and 450 nm. Data were collected using a 1 mm fiber optic needle probe. The analysis was based on the comparison of the results of deconvolution with the combinations of Gaussian curves reflecting the contribution of the pure fluorophores in the liver tissues.

RESULTS

The results showed a statistically significant increase in the contribution of curves reflecting NAD(P)H fluorescence, bilirubin, and flavins in the group of patients with obstructive jaundice. This and the calculated redox ratio values indicated that the energy metabolism of the hepatocytes may have shifted to glycolysis due to hypoxia. An increase in vitamin A fluorescence was also observed. It may also serve as a marker of liver damage, indicating impaired vitamin A mobilization from the liver due to cholestasis.

CONCLUSIONS

The results obtained reflect changes associated with shifts in the content of the main fluorophores characterizing hepatocyte dysfunction caused by accumulation of bilirubin and bile acids and after disturbance of oxygen utilization. The contributions of NAD(P)H, flavins, and bilirubin as well as vitamin A can be used for further studies as promising diagnostic and prognostic markers for the course of liver failure. Further work will include collecting fluorescence spectroscopy data in patients with different clinical effects of obstructive jaundice on postoperative clinical outcome after biliary decompression.

Fatty Acids and Bilirubin as Intrinsic Autofluorescence Serum Biomarkers of Drug Action in a Rat Model of Liver Ischemia and Reperfusion

The autofluorescence of specific fatty acids, retinoids, and bilirubin in crude serum can reflect changes in liver functional engagement in maintaining systemic metabolic homeostasis. The role of these fluorophores as intrinsic biomarkers of pharmacological actions has been investigated here in rats administered with obeticholic acid (OCA), a Farnesoid-X Receptor (FXR) agonist, proven to counteract the increase of serum bilirubin in hepatic ischemia/reperfusion (I/R) injury. Fluorescence spectroscopy has been applied to an assay serum collected from rats submitted to liver I/R (60/60 min ± OCA administration). The I/R group showed changes in the amplitude and profiles of emission spectra excited at 310 or 366 nm, indicating remarkable alterations in the retinoid and fluorescing fatty acid balance, with a particular increase in arachidonic acid. The I/R group also showed an increase in bilirubin AF, detected in the excitation spectra recorded at 570 nm. OCA greatly reversed the effects observed in the I/R group, confirmed by the biochemical analysis of bilirubin and fatty acids. These results are consistent with a relationship between OCA anti-inflammatory effects and the acknowledged roles of fatty acids as precursors of signaling agents mediating damaging responses to harmful stimuli, supporting serum autofluorescence analysis as a possible direct, real-time, cost-effective tool for pharmacological investigations.

Functional and Quality Profile Evaluation of Butters, Spreadable Fats, and Shortenings Available from Czech Market

The aim of this study was to assess the functional properties of butters, spreadable fats, and shortenings, collected from the Czech market, in correlation with their nutritional values declared by the producers. Various methods were applied to determine relevant parameters of the products. Using penetration tests, samples were characterized by specific textural attributes according to their composition and processing type, particularly for the presence of milk/vegetable fats. Using differential scanning calorimetry (DSC), thermal peaks corresponding to medium- and high-melting triacylglycerol fractions were detected in the ranges 15–16 °C and 31.5–34.5 °C, respectively. Rheological analysis revealed that the viscoelasticity of samples was related to frequency behavior of the fat structure, characterized by the dominance of elastic modulus (G′) over viscous modulus (G″) up to the frequency of 10 Hz. This indicated good emulsion stability of the products in the region of linear viscoelasticity. For spreadable fats, the structure was resistant to phase separation in the whole frequency range under study (0.1–100 Hz). The results showed that the applied techniques can be successfully used to characterize the processing and compositional quality of butters and vegetable fats.

Fluorescence excitation properties of bilirubin in solution and in serum

The bichromophore nature of bilirubin explains the presence of at least two partially overlaying bands in both absorption and fluorescence emission spectra, and accounts for interchromophore exciton transfer events responsible for the emission sensitivity to the molecular environment and excitation wavelength. These concepts were likely responsible for the previously reported good yield of the unexpected remarkable bilirubin fluorescence emission under excitation at 366 nm, at which bilirubin absorption is very low. In this connection, aim of this work is to further investigate bilirubin spectral excitation properties and their diagnostic potential, until now poorly considered. Fluorescence excitation spectra of pure bilirubin in solution with solubilizing agents observed at 520 and 570 nm showed a wide region in the 430-510 nm range, similar to the absorption profile. In addition, an excitation band centered at about 400 nm was detected. Comparable excitation features were detected in rat serum. The 430-510 nm excitation region was well separated from a main band at shorter wavelength, ascribable to other endogenous fluorophores, with a shoulder at about 400 nm which was also easily discriminated by spectral fitting analysis. The bands ascribable to bilirubin showed changes of their relative contribution to the overall spectral region after liver ischemia/reperfusion, comparable to bilirubin biochemical data. Excitation spectra proved to discriminate the fluorescence of serum bilirubin at levels much lower than emission spectra, opening promising perspectives to improve the real time fluorescence analysis of crude serum in the absence of any exogenous labelling agent, and advance the diagnostic application of optical-biopsy in experimental hepatology and biomedicine.

Photobiology and Endogenous Fluorophore Based Applications, from Natural Environment to Biomedicine to Improve Human Life

n/a