Absorption measurements of cell monolayers relevant to mechanisms of laser phototherapy: reduction or oxidation of cytochrome c oxidase under laser radiation at 632.8 nm.

Objective: The objective of this work was a further investigation of redox mechanisms of laser phototherapy on the cellular level.

Background Data: Cytochrome c oxidase, the terminal enzyme of the mitochondrial respiratory chain, is believed to work as the photoacceptor to modulate cellular metabolism in laser phototherapy.

Materials And Methods: The changes in the absorption spectra of HeLa-cell monolayers before and after irradiation at 632.

Circular dichroism of crude oil and its derivatives. Role of permolecular structures.

Petrols with different octane numbers, diesel fuel and solutions of crude oil in toluene have been studied by the methods of absorption spectroscopy, circular dichroism spectroscopy and correlation spectroscopy of scattered light. Circular dichroism signal was registered for crude oil solutions in the spectral ranges corresponding to the measured earlier resonance absorption of asphaltene solutions in toluene. We show that the optical activity of crude oil solutions is due to the aggregation of asphaltene molecules in one spectral range and is intensified with the aggregation of asphaltene molecules in another spectral range.

Exact action spectra for cellular responses relevant to phototherapy.

Objective: The aim of the present work is to analyze available action spectra for various biological responses of HeLa cells irradiated with monochromatic light of 580-860 nm.

Background Data: Phototherapy (low-level laser therapy or photobiomodulation) is characterized by its ability to induce photobiological processes in cells. Exact action spectra are needed for determination of photoacceptors as well as for further investigations into cellular mechanisms of phototherapy.

Absorption measurements of a cell monolayer relevant to phototherapy: reduction of cytochrome c oxidase under near IR radiation.

Phototherapy uses monochromatic light in the optical region of 600-1000 nm to treat in a non-destructive and non-thermal fashion various soft-tissue and neurological conditions. This kind of treatment is based on the ability of light red-to-near IR to alter cellular metabolism as a result of its being absorbed by cytochrome c oxidase. To further investigate the involvement of cytochrome c oxidase as a photoacceptor in the alteration of the cellular metabolism, we have aimed our study at, first, recording the absorption spectra of HeLa-cell monolayers in various oxygenation conditions (using fast multichannel recording), secondly, investigating the changes caused in these absorption spectra by radiation at 830 nm (the radiation wavelength often used in phototherapy), and thirdly, comparing between the absorption and action spectra recorded.