The effect of light on calcium uptake by U937 cells was studied using 45Ca radiotracer techniques. Cells were treated with light while suspended in phosphate buffered saline, and the effects of variation in energy density, pulse frequency and wavelength investigated. The results showed that calcium uptake by the cells was dependent upon the energy density of the light source. Calcium uptake increased from 0 to 4 J/cm2 but then declined steadily as the energy density was increased up to 16 J!cm2, remaining at this level which was not significantly different from the control level, as the energy density was increased up to 32 J/cm2, the maximum tested. Calcium uptake was also shown to be both frequency- and wavelength-dependent. The most effective of the frequencies tested were in the range 16-36.48 Hz, The most effective of the wavelengths tested were 660, 820 and 870 nm. The alteration in intracellular calcium levels in response to exposure to light therapy may have considerable biological and clinical significance, since calcium ions act as second messengers in many forms of cell activity, including synthesis, secretion and intracellular communication.
The effects of low reactive level laser therapy (LLLT) with an infrared diode laser on blood pressure, particularly the hypotensive effect on hypertension were studied. Essential or primary hypertension is frequently encountered, but its aetiology and consistent control elude present day medicine. Experimental animal studies have shown that hypertension causes destructive changes in the medulla oblongata and in the brain stem: arteriosclerosis, and destructive changes in brain stem cells have been demonstrated in hypertensive human patients. Various biological effects on vascular tissue have been reported for the diode laser, and so the author evaluated the GaAlAs diode laser for the treatment of hypertension by controlling the blood pressure regulatory system, irradiating the area adjacent to the medulla oblongata, Thirty patients were included in the study. Following treatment the results were graded as excellent in 6 patients (20%); good in 11 patients (37%); fair in seven cases (23%), and ineffective in 6 cases (20%), giving an overall effective rate of 80%. In 12 of the 30 patients, whose hypertension had not been effectively controlled by conventional hypotensive treatment, LLLT gave excellent results in 6, good in 5 and fair in 1 patient. In contrast, in a second group of 15 relatively normotensive control patients, there were no excellent or good results, and only 3 fair results, the remainder being graded as ineffective. It was concluded that in general there was no clear-cut hypotensive effect following LLLT with the diode laser, but when applied to the pathological condition known as essential hypertension, LLLT was noticeably effective. These findings warrant further study on this application of LLLT.
A qualirative E.P.R. (Electron Paramagnetic Resonance) study has been performed to determine the action of Low Level Lasers on living cells, Singlet oxygen (1O2) was found to be generated by Friend Erythroleukaemic Cells (FELC) after irradiating them with a HeNe laser. The production of 1O2 in the cell during irradiation was proved by an E.P.R. technique. No singlet oxygen is photoproduced by irradiating either cytochrome C or hemin. Singlet oxygen, in small amounts, is very significant in biochemical processes and hence can be important in biostimulation. It is proposed that singlet oxygen is photoproduced by the natural porphyrins in the cell.
The effects of a low-intensity laser beam in the IR-range of the spectrum (wavelength 0.89-1.3 μm) on blood microculation in man were studied when the projection of large blood vessels (femoral, carotid, popliteal arteries) and acupuncture points were irradiated. A stimulating effect of laser irradiation on the microcirculation was demonstrated, characterized by the activation of capillary bloodflow, arteliole distension, and by the reduction of the level of intravascular erythrocyte aggregation, A highly effective therapy with low-intensity lasers has been noted for treating obliterating lesions of vessels in the lower extremities and for correcting venous impairments.
A nitrogen laser operating at 337 nm, with an energy density of 2.9 mJ/cm2/pulse, and pulse rate of 2-3 pulses/s, was used to irradiate the fungal suspensions. Irradiation for 2, 5 and 10 min produced moderate inhibition of the growth of Candida albicans(C albicans), and the number of colonies formed decreased with increasing exposure time. Such irradiation in the presence of methoxsalen caused a lethal effect on the fungus, but methoxsalen application alone did no harm to it, Exposure of the fungal suspensions for 20 min resulted in a lethal effect even in the absence of methoxsalen. The findings suggest possible application of the ultraviolet (uv) laser in photochemotherapy.
The analgesic effect of laser therapy was evaluated on a group of 60 patients, who had teeth prepared to receive porcelain-fused to gold crowns. Clinical observation was performed regarding remission of pain in relation to the number of visits and the duration of therapy in minutes. The results showed the success of laser therapy in alleviating pain originating from teeth irradiated immediately after preparation at the same visit was 93,3%. In cases of teeth covered with temporary crowns, the success rate was 100%, while in uncovered teeth it was 86.7%. Teeth received laser therapy in the next visit when pain existed was 70%. In case of teeth covered with temporary crowns success was 80%, while uncovered teeth was 60% . Laser therapy presents an additional therapy to conventional methods of covering teeth after preparation with temporary crowns to alleviate pain and preserve pulp vitality during the period of permanent fixed appliance construction.