Cytochrome c oxidase is considered as the photoacceptor when eukaryotic cells are exposed to monochromatic red to near-IR radiation. Five primary mechanisms are discussed: changes in the redox properties of the respiratory chain components following photoexcitation of their electronic states, NO release from catalytic center of cytochrome c oxidase, generation of singlet oxygen, localized transient heating of absorbing chromophores, in creased superoxide anion production with a subsequent increase in the concentration of H2O2. A cascade of reactions related to the alteration of cellular homeostasis parameters (pHi, [Cai], cAMP, Eh, [ATP] and some others) is considered as a photosignal transduction and amplification chain in a cell (secondary mechanisms).
Redox absorbance changes in living cells (monolayer of HeLa) under laser irradiation at 633, 670, and 820 nm have been studied by the method of multichannel registration in spectral range 530-890 nm. It has been found that the irradiation causes changes in the absorption spectram of the cells in two regions, near 754-795 nm (maxima at 757, 775, and 795 nm) and near 812-873 nm (maxima at 819, 837, 858, and 873 nm). Changes occur in band parameters (peak positions, width, and integral intensity). Virtually no changes occur in the red spectral region and a few changes are recorded in the green region near 556-565 nm. The results obtained evidence that cytochrome c oxidase becomes more oxidized (which means that the oxidative metabolism is increased) due to irradiation at all wavelengths used. The results of present experiment support the suggestion (Karu, Lasers Life Sci., 2:53, 1988) that the mechanism of low- power laser therapy on cellular level is based on the electronic excitation of chromophores in cytochrome c oxidase which modulates redox status of the molecule and enhances its functional activity.
A sensitive method for measuring the circular dichroism (CD) of living cells in visible-near IR region is developed. The changes in CD spectra from 250 to 780 nm of HeLa cell suspension after the first and second irradiation at 820 nm in dose 9 J/cm2 are investigated. The CD spectrum of the intact cells is well structured and characterized by a positive signal in the UV (250-290 nm) and visible-near IR (500-780 nm) regions as well as by a negative signal in 300-450 nm region. Distinct maxima in the visible-near IR region are recorded at 566, 634, 680, 712, and 741 nm. As a rule, the peak circular dichroism signals decrease in the irradiated cells except of the area 750-770 nm. Peak positions (exception: the peak at 680 nm) shift as a rule to the long-wavelength direction. The most remarkable changes in peak positions as well as in CD signals are recorded in the region 750-770 nm: an appearance of the new peak at 767 nm after the first irradiation and its shift to 752 nm after the second irradiation. The peaks at 712 and 741 nm disappear after the irradiation. A new peak appears at 601 nm. It is assumed that the changes in the degree of oxidation of the chromophores of cytochrome c oxidase caused by the irradiation are accompanied by conformational changes in their vicinity. It can be suggested that these changes are occurring in CuB environment.
The aim of these experiments was a direct measurement of changes in absorption of cellular monolayers under diode laser irradiation. First, a sensitive method for multichannel registration of absorption of a cell monolayer in range 500-860 nm was developed. Second, absorption spectra of intact HeLa cells and those after irradiation the monolayer with light at 670 and 820 nm were recorded. Third, the comparison of the absorption spectra and action was performed.
The aim of these experiments was a direct measurement of changes in absorption of cellular monolayers under diode laser irradiation. First, a sensitive method for multichannel registration of absorption of a cell monolayer in range 500 - 860 nm was developed. Second, absorption spectra of intact HeLa cells and those after irradiation the monolayer with light at 670 and 820 nm were recorded. Third, the comparison of the absorption spectra and action spectra (five dependences of DNA and RNA synthesis rate and adhesive properties of HeLa cell membrane on wavelength) was performed.
This paper deals with the cytofluorimetric investigation into an early reaction of T- and B-lymphocytes from human peripheral blood (accessibility of the overall nuclear chromatin to acridine orange) to irradiation with a He-Ne laser (632.8 nm, 67 J/m2, 10 s). Our finding is that it is only the T-lymphocytes that react to the laser treatment, whereas a treatment with the mitogen phytohemagglutinin during one hour has an effect on both types of lymphocytes.
The concept of blood irradiation therapy originates from Germany (K. Naswitis) and United States (E. Knott)' in the 1920s. In their works devices for extracorporeal inadiation of small amounts of blood with UV radiation were developed. The method was used to treat bacterial, viral and autoimmune diseases but a new wave of antibiotics and vaccines in 1 950s caused the method to fall into oblivion. Its second birth occurred in former USSR in the late 1 970s - early 1 980s and got a widespread use in hundreds of clinics as well as in vetermary medicine. Beside extracorporeal UV inadiation of blood Russian doctors started to use low-intensity He-Ne laser irradiation through a fiber and a needle (intravenous inadiation). Low-intensity He-Ne and later semiconductor lasers emitting in red - to - near IR region were also used for extracorporeal and over-venous inadiation. The rise of multidrug resistance of bacterial strains, strong side effects of some effective drugs, AIDS and hepatitis have originate the interest to methods of blood inadiation also in the West. Note that a blood inadiation device (extracorporeal inadiation with UV) has received a FDA clearance (51 0 (k)status), and there appeared an ultraviolet blood inadiation website (Dr. K. Dillon).
The electrophysiological characteristics rat spinal cord neurons, rat hippocampus pyramidal neurons, guinea pig cardiomyocytes, rat brain glial cells, and bovine pulmonary artery endothelial cells were measured by the common patch- clamp technique. No light effects on the voltage-activated whole-cell ionic currents were found in any type of the cells. The only ionic current type influenced by the radiation in all the cells under study was the background single-channel currents recorded inn the cell-attached configuration. The opening frequency of the background single channels was suppressed by the light and the open state probability was decreased under the irradiation. The same channels in the inside-out patches were found to be light insensitive.
The aim of these experiments was a direct measurement of changes in absorption of cellular monolayers under diode laser irradiation. First, a sensitive method for multichannel registration of absorption of a cell monolayer in range 500-8060 nm was developed. Second, absorption spectra of intact HeLa cells and those after irradiation the monolayer with light at 670 and 820 nm were recorded. Third, the comparison of the absorption spectra and action spectra was performed.
Chemiluminescence test results were used to evaluate the sensitivity of human blood and murine splenocytes to continuous-wave (CW) and pulsed He-Ne laser light. It is demonstrated that CW radiation has in our experimental conditions practically no effect on the luminol-amplified chemiluminescence of four models under study. The pulsed radiation had a week inhibiting effect on the samples from healthy organisms but inhibited markedly the chemiluminescence of samples from tumor-bearing organisms. The effect depended on duration of dark period between pulses. A transient local heating mechanism is proposed to explain the inhibition of activity of NADPH-oxidase.
A monolayer of HeLa cells in plateau-phase of growth was exposed to He-Ne laser radiation either 5 min, 60 min or 180 min before (gamma) -irradiation. It has been shown that in the case of a 5-min interval between the two types of irradiations the survival curve was practically identical to the survival curve of the cells after (gamma) -irradiation only. In the case of He-Ne laser exposure 60 min before (gamma) -irradiation with doses of over 5 Gy, a fraction of more resistant cells was revealed: their D0 was twice as high as the D0 of the min population. A preexposure of cells to He-Ne laser 60 or 180 min before (gamma) - irradiation also changed the shape of the growth curves as compared to (gamma) -irradiated cells. It is proposed that the preexposure of cells to He-Ne laser radiation activates, in a subpopulation of cells, processes which speed up the repair of (gamma) -radiation damage. The possibility that the described phenomenon is an adaptive response of cells is discussed.
The structure of mitochondria was studied after irradiation of human lymphocytes with an HeNe laser. Ultrathin sections of the lymphocytes were studied by electron microscopy 1 h after the irradiation. The irradiation resulted in a 20 percent increase in the mean number of mitochondrial profiles on cell section without increase in their total area. 3D reconstruction of mitochondria from ultrathin sections through the whole lymphocyte showed that the number of mitochondria was reduced to 9-12 in the irradiated cells compared to 40-45 in the control cells. In the irradiated lymphocytes also 2-4 branching giant mitochondria were revealed among of small discrete mitochondria.
Biological responses of cells to visible and near IR (laser) radiation occur due to physical and/or chemical changes in photoacceptor molecules, components of respiratory chains (cyt a/a3 in mitochondria). As a result of the photoexcitation of electronic states, the following physical and/or chemical changes can occur: alteration of redox properties and acceleration of electron transfer, changes in biochemical activity due to local transient heating of chromophores, one-electron auto-oxidation and O2- production, and photodynamic action and 1O2 production. Different reaction channels can be activated to achieve the photobiological macroeffect. The primary physical and/or chemical changes induced by light in photoacceptor molecules are followed by a cascade of biochemical reactions in the cell that do not need further light activation and occur in the dark (photosignal transduction and amplification chains). These actions are connected with changes in cellular homeostasis parameters. The crucial step here is thought to be an alteration of the cellular redox state: a shift towards oxidation is associated with stimulation of cellular vitality, and a shift towards reduction is linked to inhibition. Cells with a lower than normal pH, where the redox state is shifted in the reduced direction, are considered to be more sensitive to the stimulative action of light than those with the respective parameters being optimal or near optimal. This circumstance explains the possible variations in observed magnitudes of low-power laser effects. Light action on the redox state of a cell via the respiratory chain also explains the diversity of low-power laser effects. Beside explaining many controversies in the field of low-power laser effects (i.e., the diversity of effects, the variable magnitude or absence of effects in certain studies), the proposed redox-regulation mechanism may be a fundamental explanation for some clinical effects of irradiation, for example the positive results achieved in treating wounds, chronic inflammation, and ischemia, all characterized by acidosis and hypoxia.
Luminol-amplified chemiluminescence was recorded after irradiation with laser radiation at 632.8 and 820 nm. The following cellular systems were used as objects of irradiation: blood of healthy donors, blood of patients with colon cancer or acute respiratory illness, blast cells of patients with acute leukemia. The irradiation was suppressing the oxidative metabolism of cellular systems under study.
Biological responses of cells to visible and near IR (laser) radiation occur due to physical and/or chemical changes in photoacceptor molecules, components of respiratory chains (cyt a/a3 in mitochondria). As a result of the photoexcitation of electronic states, the following physical and/or chemical changes can occur: alteration of redox properties and acceleration of electron transfer, changes in biochemical activity due to local transient heating of chromophores, one-electron auto-oxidation and O'2- production, and photodynamic action and 1O2 production. Different reaction channels can be activated to achieve the photobiological macroeffect. The primary physical and/or chemical changes induced by light in photoacceptor molecules are followed by a cascade of biochemical reactions in the cell that do not need further light activation and occur in the dark (photosignal transduction and amplification chains). These reactions are connected with changes in cellular homeostasis parameters. The crucial step here is thought to be an alteration of the cellular redox state: a shift towards oxidation is associated with stimulation of cellular vitality, and a shift towards reduction is linked to inhibition. Cells with a lower than normal pH, where the redox state is shifted in the reduced direction, are considered to be more sensitive to the stimulative action of light than those with the respective parameters being optimal or near optimal. This circumstance explains the possible variations in observed magnitudes of low- power laser effects. Light action on the redox state of a cell via the respiratory chain also explains the diversity of low-power laser effects. Besides explaining many controversies in the field of low-power laser effects (i.e., the diversity of effects, the variable magnitude or absence of effects in certain studies), the proposed redox-regulation mechanism may be a fundamental explanation for some clinical effects of irradiation, for example the positive results achieved in treating wounds, chronic inflammation, and ischemia, all characterized by acidosis and hypoxia.
Biological responses of cells to visible and near IR (laser) radiation occur due to physical and/or chemical changes in photoacceptor molecules, components of respiratory chains (cyt a/a3 in mitochondria, and cyt d in E. coli). As a result of the photoexcitation of electronic states, the following physical and/or chemical changes can occur: alteration of redox properties and acceleration of electron transfer, changes in biochemical activity due to local transient heating of chromophores, one-electron auto-oxidation and O2- production, and photodynamic action and 1O2 production. Different reaction channels can be activated to achieve the photobiological macroeffect. The primary physical and/or chemical changes induced by light in photoacceptor molecules are followed by a cascade of biochemical reactions in the cell that do not need further light activation and occur in the dark (photosignal transduction and amplification chains). These reactions are connected with changes in cellular homeostasis parameters. The crucial step here is thought to be an alteration of the cellular redox state: a shift towards oxidation is associated with stimulation of cellular vitality, and a shift towards reduction is linked to inhibition. Cells with a lower than normal pH, where the redox state is shifted in the reduced direction, are considered to be more sensitive to the stimulative action of light than those with the respective parameters being optimal or near optimal. This circumstance explains the possible variations in observed magnitudes of low-power laser effects. Light action on the redox state of a cell via the respiratory chain also explains the diversity of low-power laser effects. Beside explaining many controversies in the field of low-power laser effects (i.e., the diversity of effects, the variable magnitude or absence of effects in certain studies), the proposed redox-regulation mechanism may be a fundamental explanation of some clinical effects of irradiation, for example the positive results achieved in treating wounds, chronic inflammation, and ischemia, all characterized by acidosis and hypoxia.
The aim of this paper is to show relationship first, between light parameters
and biostimulation (metabolism regulation effect), and second, between physiological
conditions of cells at the moment of irradiation and stimulation effects magnitude.
These studies have been performed on cellular level, and as a model, a culture of
procaryotic cells Escherichia coil WP2 was used. As a criterion for the division
rate of E. coil WP2 cells was measured.
There is no grounds to believe the existence of a single universal biostimula
tion mechanism active on molecular, cellular, and organism levels. On the other
hand, undoubtedly there are many connections between mechanisms of light stimulation
on different levels. For example, as concerning light stimulation on organism level
(i.e., low-power laser therapy), there exist dependences of therapeutic effects on
parameters of light (fluence, intensity) (see reviews: Karu, 1990 a, b). As far as
mechanism of biostimulation is concerned, we will show in this paper that the stimulation
effects are connected with certain chromophores (primary photoacceptors) in
a cell.
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