[Loosening of condensed chromatin in human blood lymphocytes exposed to irradiation with a low-energy He-Ne laser].

It was shown that, 1 h after irradiation of human blood lymphocytes with a He-Ne laser at 56 J/m2 (5.6 W/m2, 10 s), the relative optical density of condensed chromatin masses observed in ultrathin sections was decreased (p < 0.01); i.e., the condensed chromatin became less compact. Such transition of condensed chromatin to a more "open" state may improve its availability for regulatory proteins and transcriptional factors. The irradiation also results in dispersion of condensed chromatin clumps in the nucleoplasm and enhancement of their angularity, i.e., in extension of the clump surface. These shifts, correlating with the activation of transcription, may be due to decompaction of the chromatin fibers not only on the periphery of chromatin clusters in the center of the nucleus, but also within the masses of condensed chromatin.

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. METHODS: Seven action spectra for the stimulation of DNA and RNA synthesis rate and cell adhesion to glass matrix are analyzed by curve fitting, followed by deconvolusion with Lorentzian fitting. Exact parameters of peak positions and bandwidths are presented. RESULTS: The peak positions are between 613.5 and 623.5 nm (in one spectrum, at 606 nm), in the red maximum. The far-red maximum has exact peak positions between 667.5 and 683.7 nm in different spectra. Two near infrared maxima have peak positions in the range 750.7-772.3 nm and 812.5-846.0 nm, respectively. CONCLUSIONS: In the wavelength range important for phototherapy (600-860 nm), there are four "active" regions, but peak positions are not exactly the same for all spectra.

[Structure of mitochondria and activity of their respiratory chain in subsequent generations of yeast cells exposed to He-Ne laser light].

The data on the effect of He-Ne laser light (lambda = 632.8 nm) on mitochondria of yeasts in late log phase were reviewed. The qualitative analysis of the ultrathin sections of cells demonstrated a nonuniform thickness of the giant branched mitochondria typical for budding yeasts. Exposure to a dose of 460 J/m@2 accelerated cell proliferation, activated respiratory chain enzymes (cytochrome c oxidase and NADH dehydrogenase), and also changed the microstructure of the giant mitochondria--much of the narrow regions of the mitochondrial tube with sections < or = 0.06 microm2 were dilated (while no signs of organelle damage were observed). Relative surface area of the cristae increased in such mitochondria, which can be due to the activation of their respiration and ATP synthesis. The number of associations between mitochondria and endoplasmic reticulum increased in cells in early log phase, which reflects high capacity of mitochondria to absorb Ca2+. Altered giant mitochondria configuration can increase the efficiency of both energy transfer and Ca2+ distribution in the cytoplasm.

Donors of NO and pulsed radiation at lambda = 820 nm exert effects on cell attachment to extracellular matrices.

The adhesion of HeLa cells to a glass matrix was evaluated after the irradiation of the cell suspension with a pulsed near-infrared light-emitting diode (lambda = 820 nm, frequency 10 Hz, dose 8-120 J/m(2)) and treatment with two donors of nitric oxide, sodium nitroprusside (SNP, 5 x 10(-4) M) and NaNO(2) (4 x 10(-4) M). It was found that in an irradiated cell suspension, the cell-glass adhesion increases in a dose-dependent manner (a bell-shaped curve with a maximum at 60 J/m(2)). The treatment of cells with SNP or NaNO(2) before the irradiation eliminates the radiation-induced attachment stimulation. Pretreatment of cells with SNP not only eliminates the radiation-induced attachment stimulation but inhibits the attachment of irradiated (but not non-irradiated) cells. It is suggested that a modulation of the activity of respiratory chain (probably the alteration of the activity of cytochrome c oxidase) is involved in radiation-induced increase of cell attachment.

Comparison of the effects of visible femtosecond laser pulses and continuous wave laser radiation of low average intensity on the clonogenicity of Escherichia coli.

To evaluate the contribution of local pulsed heating of light-absorbing microregions to biochemical activity, irradiation of Escherichia coli was carried out using femtosecond laser pulses (lambda = 620 nm, tau p = 3 x 10(-13) S, fp = 0.5 Hz, Ep = 1.1 x 10(-3) J cm-2, Iav = 5.5 x 10(-4) W cm-2, Ip = 10(9) W cm-2) and continuous wave (CW) laser radiation (lambda = 632.8 nm, I = 1.3 W cm-2). The irradiation dose required to produce a similar biological effect (a 160%-190% increase in the clonogenic activity of the irradiated cells compared with the non-irradiated controls) is a factor of about 10(3) lower for pulsed radiation than for CW radiation (3.3 X 10(-1) and 7.8 X 10(2) J cm-2 respectively). The minimum size of the microregions transiently heated on irradiation with femtosecond laser pulses is estimated to be about 10 A, which corresponds to the size of the chromophores of hypothetical primary photoacceptors--respiratory chain components.

[Growth kinetics of HeLa tumor cells during subculturing after irradiation with low-intensity red light in the stationary growth phase]. / Kinetika rosta opukholevykh kletok HeLa pri subkul'tivirovanii posle oblucheniia nizkointensivnym krasnym svetom v statsionarnoi faze rosta.

The curves of relative growth rate of HeLa cells were studied after their irradiation at the stationary growth phase (He-Ne laser, lambda = 632.8 nm, D = 100 J/m2) and reinoculation to the fresh medium in different periods after the irradiation. The irradiation evokes changes in cells of the stationary phase which are realized in subcultivation. When the interval between irradiation and inoculation is short (5 min), the cell growth is inhibited; when the interval becomes longer (up to 4 h), the cell growth in the exponential phase increases. In the HeLa cell culture with the stimulated growth only a part of cells are able, to reach the stationary growth phase.

[A comparative study of chromatin from lymphocyte nuclei upon activation of transcription by irradiation from an He-Ne-laser or phytohemagglutinin]. / Sravnitel'noe issledovanie khromatina iader limfotsitov pri aktivatsii transkriptsii deistviem izlucheniia He-Ne-lazera ili fitogemaggliutinina.

The influence of He-Ne laser radiation (632.8 nm, 56 J/m2, t = 10 s) and phytohaemagglutinin (PHA, 2 micrograms/ml) on chromatin structure in human lymphocytes was studied by electron microscopy using ultrathin cell sections. Morphometric analysis of extranuclear condensed chromatin masses was performed 1 h after the irradiation or after the beginning of PHA treatment. In the irradiated cells the following insignificant changes were revealed: decrease in the relative area of the nucleoplasmic chromatin, increase in the relative area of decondensation zones as well as increase in the number of clumps of nucleoplasmic chromatin and relative length at their boundary with nucleoplasma. The tendency of these morphological changes may be interpreted as functional activation of extranucleolar RNA synthesis in response to irradiation by red laser light. Action of PHA results in significant changes of the surfaces of chromatin clumps, namely increase in relative length of nucleoplasmic chromatin boundary and decrease in relative length of perimembranous chromatin boundary with nucleoplasma as well as some less expressed delamination of the chromatin masses from the nuclear membrane. These essential changes may reflect chromatin activation by proliferative stimulus. Peculiarities of the ultrastructural reorganisation in the condensed chromatin after irradiation and PHA-treatment probably reflect the differences in the processes of gene activation caused by the two agents.

[The effect of irradiation by a He-Ne laser and phytohemagglutinin on lymphocyte mitochondria]. / Reaktsiia mitokhondrial'nogo appparata limfotsitov na obluchenie He-Ne-lazerom i na mitogen fitohemaggliutinin.

Electron-microscopic morphometry has been applied to study mitochondria on ultrathin sections of lymphocytes from human peripheral blood. It has been shown that the stimulation of lymphocytes by the mitogen phytohemagglutinin (PHA) 1 h causes increases in the quantity of mitochondria per cellular section (17%) as well as in the total area of mitochondria per cell section (35%), i.e. an increase in mitochondrial mass. Taking into account known facts about growth and division of mitochondria in late phases of cellular cycle, one can suppose that described above changes in mitochondria during G0----G1 transition under action of PHA belong to an early phase of biogenesis of mitochondria. In the contrary, irradiation of lymphocytes with He-Ne-laser (lambda = 632.8 nm) in dose 56 J/m2 which does not cause the G0----C1 transition, results in the increase in the number of mitochondria per cellular section (20%) but not increase in the total area of mitochondria per cell section. The last finding indicates to some modification of space configuration of the mitochondria without any changes in their mass. The increase in the quantity of mitochondria per cellular section after the irradiation could be related with the increase in electrochemical proton gradient and in phosphorylating activity of mitochondria. He-Ne-laser radiation as well as mitogen PHA cause some deaggregation of mitochondria (this is more pronounced in case of PHA) which may be related to their functional activation.

[Activation of transcription function in lymphocytes after irradiation with He-Ne-laser]. / Aktivatsiia transkriptsionnoi funktsii v limfotsitakh pod vliianiem oblucheniia He-Ne-lazerom.

The influence of He-Ne-laser irradiation (lambda = 632.8 nm) in dose 56 J/m2 on the ultrastructure of the nucleolus from human peripheral lymphocytes was studied electronmicroscopically. After 1 h irradiation a well-expressed reaction of the nucleolus was observed in 70% of the lymphocytes under examination. Changes consist in the appearance of a wrong-shaped fibrillar center or in its fragmentation, the increase of RNP-containing fibrillar and granular components, and also in expansion of vacuoli. In a number of irradiated lymphocytes nucleoli with several fibrillar centres and with a strand-like organization of RNP part were observed. The size of these nucleoli increases. Following the accepted functional interpretations the observed changes can be connected with the intensification of RNA metabolism including the synthesis, processing of pre-rRNA and preribosome transport from the nucleolus. Similar rearrangements of the nucleoli were revealed in parallel experiments with phytohemagglutinin-treated lymphocytes. They were observed 1 h after the stimulation of lymphocytes. Taking into account the absence of mitogenic action of He-Ne-laser irradiation on lymphocytes, the ultrastructural changes of nucleoli under the action of irradiation are considered as functional activation of rRNA synthesis in the Go-period.

[Formation of gigantic mitochondria in human blood lymphocytes under the effect of an He-Ne laser]. / Poiavlenie gigantskikh mitokhondrii v limfotsitakh krovi cheloveka pod vliianiem izlucheniia He-Ne lazera.

A phenomenon of formation of giant mitochondria in lymphocytes after He-Ne-laser irradiation (56 J/m2, 5.6 W/m2) was discovered. Reconstruction of mitochondria from ultrathin sections through the whole lymphocyte showed that 1 h after the irradiation the number of mitochondria was reduced to 9-12 compared to 40-45 in the control cells. In the irradiated lymphocytes 2-4 branching giant mitochondria were revealed instead of small discrete mitochondria in the control cells. Other 6-7 mitochondria were found to retain their shape and volume. It is suggested that the giant mitochondria are formed by fusion of small mitochondria. Formation of giant mitochondria may reflect the increase in the energy exchange level.

[Increase in the number of contacts of endoplasmic reticulum with mitochondria and plasma membrane in yeast cells stimulated to division with He-Ne laser light]. / Uvelichenie kolichestva assotsiatsii éndoplazmaticheskogo retikuluma s mitokhondriiami i plazmaticheskoi membranoi v drozhzhevykh kletkakh, stimulirovannykh k deleniiu svetom He-Ne-lazera.

We studied the ultrastructure of Torulopsis sphaerica yeast cells irradiated with He-Ne laser (lambda = 632.8 nm, dose--460 J/m2) and then cultured for 6 h in the nutrient with 1% glucose by aeration. The length of membranes of endoplasmic reticulum (ER) and the number of its associations with mitochondria (M) and plasma membrane (PM) were measured on ultrathin sections. A distance of less than 50 nm between heterogeneous membranes was considered as an "association". The cells from irradiated cultures are characterized by the following features: 1) the length of cortical ER membranes in relation to cellular perimeter, and the length of perinuclear ER membranes in relation to nuclear perimeter increase, resp., by 21 and 79%; 2) the number of ER-PM associations per cellular section, and that per unit of PM length increase, resp., by 26 and 41%; 3) the number of ER-M association in relation to the total mitochondrial perimeter, and to perimitochondrial ER increase by 80 and 87%, resp. The latter may be associated with Ca2+ uptake by mitochondria associated with ER, which results in activation of respiration and ATP production.

[Change in the metabolism and toxic effect of benz(a)pyrene by its metabolites and a series of phenols]. / Izmenenie metabolizma i toksicheskogo deistviia benz(a)pirena s pomoshch'iu ego metabolitov i riada fenolov

Effects of some phenols and polycyclic aromatic hydrocarbon derivatives on benz(a)-pyrene metabolism have been studied in the microsomal system isolated from the mouse embryonic cell cultures. The rate of benz(a)pyrene metabolism was shown to depend on the structure and concentration of the agents added. The toxic effect of benz(a)pyrene was summed up with that of either agent studied (except ionol) added simultaneously to the cell culture.

[Morphometric study of yeast cells of Torulopsis sphaerica after He-Ne-laser irradiation]. / Mopfometricheskoe issledovanie drozhzhevykh kletok Torulopsis sphaerica posle oblucheniia svetom He-Ne-lazera.

A study was made of structural organization of Torulopsis sphaerica cells irradiated with He-Ne (lambda = 632.8 nm; dose--460 J/m2) and then cultured in the nutrient with 1% glucose and O2 for 6 h. The computer analysis of electron images of cell sections was carried out. Evidences of stimulation of cell proliferation were found, including decrease in the areas of cell and chondriome profiles, decrease in the number of mitochondria on sections, elongation of cells and mitochondria, and increased variability of cell parameters. In addition, cells of irradiated cultured were characterized by the increase in the number of mitochondria contacting the endoplasmic reticulum (in this case the outer mitochondrial membrane presumably associates with the ER membrane), which may suggest the activation of ATP synthesis. Thus, He-Ne laser irradiation activates cell metabolism even at the early stage of culture growth.

[Effect of low-intensity periodic-impulse laser UV radiation on the nucleic acid synthesis rate in proliferating and resting cells]. / Vliianie nizkointensivhnogo impul'sno-peridicheskogo lazernogo UF-izlucheniia na skorost' sinteza nukleinovykh kislot v proliferiruiushchikh i pokoiashchikhsia kletkakh.

A study was made of the effect of the low intensity (10(-6)--10(3)/cm3) high repetition rate (pulse duration 18 nseconds, repetition rate 10 KHz) UV radiation (2nd harmonic of Cu vapour laser, lambda = 271.2 nm) on proliferating and resting cells (HeLa and fibroblast-like cells of Chinese hamster 431). The treatment within the dose range from 0.05 to 5 J/m3 stimulates DNA synthesis in the resting cells rather than in the proliferating ones. It was shown autoradiographically that, within the same dose range, the number of synthesizing cells increased in 2.5 hour.

[Is the coherence of low-intensity laser light essential for its effect on biological objects?]. / Sushchestvenna li kogerentnost' nizkointensivnogo lazernogo sveta pri ego vozdeistvii na biologicheskie ob''ekty?

Low-intensity laser light coherence is considered in relation to biological objects under normal physiological conditions. Estimations show that the excitation rate (the rate of coherent states generation) of typical biomolecules in visible range (sigma abs = 10(-17) cm2, I = 10(-3) W/cm2) is 10(12)-10(13) times lower than that of their phase relaxation. It means that the role of coherent interaction processes is negligible. This conclusion is confirmed by the experimental results obtained with living cells of different types.