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Biomedical subjects

G S Kalendo

Publications and source records attributed to G S Kalendo.

At least 19 recordsLinked to original sources
PubMed2001

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.

Cell Adhesion↗
PubMed2001

Cell attachment modulation by radiation from a pulsed light diode (lambda = 820 nm) and various chemicals.

BACKGROUND AND OBJECTIVE: Adhesive interactions between cells and extracellular matrices play a regulative role in wound repair processes. The objective of this investigation is to study the mechanisms of light action on cellular adhesion in vitro. The adhesion of HeLa cells to a glass matrix is evaluated after irradiation with a pulsed near-infrared (IR) diode and treatment with various chemicals. STUDY DESIGN/MATERIALS AND METHODS: A semiconductor diode (820 +/- 10 nm, 10Hz, 16--120 J/m(2)) is used for irradiation of the cell suspension. In parallel experiments, various chemicals (mannitol, melatonin, ethanol, ascorbic acid, superoxide dismutase, catalase, rotenone, azide, dinitrophenol (DNP), methylene blue, and hydrogen peroxide) are added to the cell suspension before or after the irradiation procedure. The cell-glass adhesion is studied by using the adhesion assay technique (Lasers Surg. Med. 1996;18:171). RESULTS: It has been found that cell-glass adhesion increases in a dose-dependent manner after irradiation. The treatment of the cells with antioxidants (free radical scavengers), e.g., mannitol, melatonin, ethanol, and ascorbic acid, as well as with the ionophore DNP, eliminated the light effect. The respiratory chain inhibitors rotenone and azide strongly modified the light effect, depending on the dose. The oxidative agents hydrogen peroxide (in a low concentration) and methylene blue increased the cell adhesion. Superoxide dismutase did not modify the light effect. The effect of the catalase (stimulative or suppressive) was dependent on its concentration and treatment sequence. Preirradiation was found to decrease (or normalize to the control level) the suppressive effects of some chemicals. CONCLUSION: The results obtained are evidence that first, pulsed IR radiation with certain parameters modulates the cell-matrix attachment. second, free radical and redox processes are involved in the cell-matrix interaction, probably at some stage(s) of the photosignal transduction. Third, both types of the primary reactions in the respiratory chain, namely, the increase of the electron flow and production of the reactive oxygen species, cause a transient oxidative stress in the cytoplasm.

Ascorbic Acid↗
PubMed2001

Cell attachment to extracellular matrices is modulated by pulsed radiation at 820 nm and chemicals that modify the activity of enzymes in the plasma membrane.

BACKGROUND AND OBJECTIVES: Adhesive interactions between cells and extracellular matrices play a regulative role in wound repair processes. The objective of this investigation is to study action mechanisms of pulsed radiation at 820 nm on cellular adhesion in vitro. Light emitting diodes (LED) at 820 nm are widely used for treatment of wounds of various etiology. STUDY DESIGN/MATERIALS AND METHODS: The LED (820 +/- 10 nm, 10 Hz, 16-120 J/m(2)) is used for the irradiation of HeLa cell suspension. In parallel experiments, amiloride (5 x 10(-4) M), ouabain (7 x 10(-5) M, 7 x 10(-4) M), quinacrine (6 x 10(-4) M), arachidonic acid (1 x 10(-5) M), glucose (2 x 10(-4) M), and ATP (5 x 10(-5) M) are added to the cell suspension before or after the irradiation procedure. The cell-glass adhesion is studied using the adhesion assay technique described in Lasers Surg Med 1996; 18:171. RESULTS: Cell-glass adhesion increases in a dose-dependent manner following the irradiation. Preirradiation eliminates the inhibition of cell attachment caused by ouabain, arachidonic acid, and ATP. The inhibitive effect of quinacrine on the cell attachment is eliminated by the irradiation performed after the treatment with the chemical. Irradiation and amiloride have a synergetic stimulative effect on the cell attachment. The threshold dose for the cell attachment stimulation by the irradiation is decreased by the treatment of the cell suspension with amiloride or ouabain. CONCLUSIONS: The results obtained indicate that pulsed IR radiation at 820 nm increases the cell-matrix attachment. It is the modulation of the monovalent ion fluxes through the plasma membrane and not the release of arachidonic acid that is involved in the cellular signaling pathways activated by irradiation at 820 nm. Preirradiation has a protective effect against the inhibitive action of ouabain, arachidonic acid, ATP, and quinacrine on cell attachment process. It is supposed that irradiation activates those signaling pathways in cells which attenuate the inhibitive action of these chemicals.

Adenosine Triphosphate↗
PubMed1996

Effects of monochromatic low-intensity light and laser irradiation on adhesion of HeLa cells in vitro.

BACKGROUND AND OBJECTIVE: The adhesion of HeLa cells was evaluated after irradiation with monochromatic low-intensity light or laser irradiation. It is well known that the cell-cell and cell-matrix adhesion changes during wound repair. For better understanding of low-power laser light action on the wound healing process, it would be of interest to study the light action on cellular adhesion in vitro. STUDY DESIGN/MATERIALS AND METHODS: The monochomatic light was in the range 580-860 nm (bandwidth 10 nm, 5-150 J/m2 1.3 W/m2) and the He-Ne laser irradiation was 632.8 nm (100 J/m2, 10 W/m2). Cell-cell and cell-glass adhesion were evaluated after irradiation of HeLa cells. RESULTS: It was found that cell-cell and cell-glass adhesion increased following irradiation depending on the irradiation conditions (wavelength, dose) and the time elapsed after the irradiation. The cell attachment to glass surface increased after irradiation of samples of HeLa cells in suspension. CONCLUSION: The adhesion was stimulated in the wavelength ranges 600-625, 645-700, and 720-850 nm with maxima at 620, 680, 750, and 820-830 nm, respectively.

Cell Adhesion↗
PubMed1993

Evidence for formation of somatic cell hybrids in a population of irradiated cells.

Experiments using two genetically marked lines of Djungarian hamster cells (DM-15 HPRT- and DH-TK-) and the technique of hybrid selection in selective HAT medium revealed viable colonies in a mixed culture irradiated with a dose of 5 Gy. The sublines grown from these colonies were examined. Chromosome analysis showed that about 45% of those cells were hybrids inheriting chromosome markers of both parent strains. Formation of radio-induced hybrids occurs as a function of time after irradiation, 6 days proving to be the optimal interval. It is postulated that radiation-induced cell fusion and formation of viable somatic cell hybrids may be essential for cell population survival in the course of tumour radiotherapy.

Animals↗
PubMed1993

[Changes in the amount of ATP in HeLa cells under the action of He-Ne laser radiation].

Amount of ATP in HeLa cells in various phases of growth was measured after He-Ne laser irradiation (100 J/m2, 10 W/m2, 10 s) by a bioluminescent luciferin-luciferase method. In cells of the exponential phase of growth, the amount of ATP (basal level 8 x 10(-16) mole/cell) starts to increase in 15 min after the irradiation with a maximum (170% above the basal level) at 20 min, and then decreases gradually to the basal level. The sensitivity of the cells to He-Ne laser radiation is lowest in lag-phase of growth, then increases to a plateau (approximately 185% above the control level) from 5th day of cultivation.

Adenosine Triphosphate↗
PubMed1993

[The effect of He-Ne laser radiation on the adhesive properties of the cell membrane].

Changes in the number of individual cells and cellular complexes after a standard dispergation procedure were used as a criterion for evaluating the strength of the cellular contacts at various time-points after the irradiation of HeLa monolayers with a He-Ne laser (100 J/m2, 10 W/m2, 10 s). The per cent of cellular complexes increased after the irradiation, being maximal (19.5 +/- 0.6) at 30 minutes of post-irradiation, and then decreased to the control level (12.1 +/- 0.5). Per cent of cellular complexes increased again at longer intervals (90-180 min) after the irradiation.

Cell Adhesion↗
PubMed1987

[The structure of HeLa cell population after exposure to methylnitrosourea at different phases of culture growth].

To study the methylnitrosourea (MNU) effect on the HeLa cells culture at different stages of its growth the method of subcultivation, i. e. dissemination of cells immediately after the MNU effect, has been used followed by the study of the growth pattern of the reinoculated culture. When dissemination was carried out on the 4th, 7th and 10th day of the culture growth after the action of MNU, the highest growth inhibition effect was observed at the late stationary growth stage of the culture (the 10th day). The study of the population structure of such a culture by the method of batch cytofluorimetry has shown that MNU exerts a cytotoxic effect on cells: there is a shift in cell distribution according to the DNA content towards 4c typical of the G2/M-period of the cell cycle.

Cell Division↗
PubMed1984

[The effect of hyperthermia on proliferating and resting HeLa cells].

The action of hyperthermia (42 degrees C, 10-60 min) on HeLa cells was studied at the logarithmic and stationary growth stages. It is shown that changes in the cell number, DNA synthesis, incorporation of 3H-thymidine, and 14C-3-O-methylglucose caused by hyperthermia depend on the initial physiological state of cells.

3-O-Methylglucose↗
PubMed1984

[Growth kinetics of HeLa tumor cells during subculturing after irradiation with low-intensity red light in the stationary growth phase].

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.

Cell Cycle↗
PubMed1984

[Clinical studies of the radiosensitizing effect of small doses of ionizing radiation (preliminary data)].

The authors present the preliminary clinical results of radiation therapy of patients with uterine tumors (adenogenic endometrial cancer) under the conditions of short-term stimulation of proliferation with small doses of ionizing radiation to enhance the damaging effect of the main radiation. The results of a cytological study of 72 patients and 2-year follow-up results of 20 patients show that the use of small radiation doses as a radiosensitizing factor in radiation therapy of resistant cancer types holds promise. It is advisable that these studies should be continued.

Adenocarcinoma↗