Helium-neon Laser Irradiation Research Articles

Systemic effects of low-power laser irradiation on the peripheral and central nervous system, cutaneous wounds, and burns.

In this paper, we direct attention to the systemic effect of low-power helium-neon (HeNe) laser irradiation on the recovery of the injured peripheral and central nervous system, as well as healing of cutaneous wounds and burns. Laser irradiation on only the right side in bilaterally inflicted cutaneous wounds enhanced recovery in both sides compared to the nonirradiated control group (P less than .01). Similar results were obtained in bilateral burns: irradiating one of the burned sites also caused accelerated healing in the nonirradiated site (P less than .01). However, in the nonirradiated control group, all rats suffered advanced necrosis of the feet and bilateral gangrene. Low-power HeNe laser irradiation applied to a crushed injured sciatic nerve in the right leg in a bilaterally inflicted crush injury, significantly increased the compound action potential in the left nonirradiated leg as well. The statistical analysis shows a highly significant difference between the laser-treated group and the control nonirradiated group (P less than .001). Finally, the systemic effect was found in the spinal cord segments corresponding to the crushed sciatic nerves. The bilateral retrograde degeneration of the motor neurons of the spinal cord expected after the bilateral crush injury of the peripheral nerves was greatly reduced in the laser treated group. The systemic effects reported here are relevant in terms of the clinical application of low-power laser irradiation as well as for basic research into the possible mechanisms involved.

Relative volume of membrane microflora and epitheliocyte morphology after combined helium-neon laser irradiation of chronic gastric ulcers and vagotomy

The relative volume of the microflora located directly on the surface of epitheliocytes in different parts of the stomach, especially the pyloroantral part, to which the name membrane microflora (MM) has been given, is increased in chronic ulcers and after vagotomy [4]. The gastric microflora and, in particular, Cc~rpylobacter pyloridis, are ascribed an important role in the development of gastritis and peptic ulcer [8, 12, 13].

Effect of helium-neon laser irradiation of the gastricmucosa on its epithelial cells

Effect of helium-neon laser irradiation of the gastricmucosa on its epithelial cells

Biological effect of low-power helium-neon (HeNe) laser irradiation

The functional effects (activation and cell damage) of low-power, continuous-wave HeNe laser irradiation were studied in different in vitro cultured cell lines. A characteristic dose-dependence was observed between 0.14 and 28.0 J/cm2. The functional activation (increased phagocytic activity, immunoglobulin secretion) or cell destruction could not be detected after irradiation by normal monochromatic light of the same wavelength and energy output. The experiments suggested that low-power laser irradiation has a specific influence on the cells which depends on the coherent and polarized physical features of the laser light.

Effects of the helium-neon laser on rat kidney epithelial cells in culture

The cellular mechanisms of action of low power lasers are only partially understood. Therefore, we have studied effects of helium-neon (He−Ne) laser irradiation in a cell culture model. The studies were performed with the permanent rat kidney cell line RK-L. By electron microscopy, significant ultrastructural changes of the cells were seen after He−Ne irradiation at 40 mW/cm2 for 4h (569 J/cm2), including detritus-like formations of the cell organelles close to the nucleus. While such changes were not observed after 1 h irradiation (142 J/cm2), the number of cells in mitosis increased under this condition. In addition, the rate of incorporation of3H-thymidine into DNA decreased transiently 6–9 h after 1 h He−Ne irradiation of the cells. The consumption of glucose was also lowered for 10 h after irradiation, while the production of lactate increased. Finally, the synthesis of prostaglandin E2 was reduced following irradiation. These results show that the He−Ne laser induces significant effects at the cellular level. In addition, our findings support the concept that the biological effects of low power laser treatment involve changes in the cell cycle.

Absorption of helium-neon laser radiation with a wavelength of 5.4 ?m in nitrogen oxide

Absorption of helium-neon laser radiation with a wavelength of 5.4 ?m in nitrogen oxide

Luminescence and Raman Spectroscopic Characterization of Tyrosine Oxidized by Persulfate

To gain insight into the photochemistry of oxidized amino acids, we have measured chemiluminescence and Raman spectra of persulfate oxidized tyrosine (POT). Chemiluminescence kinetics were obtained from a sealed capillary tube containing a basic POT solution. Excitation at 488.0 nm and monitoring emission at 633 nm produced a first-order rise and a second-order decay in intensity to steady-state levels. We collected steady-state emission spectra from a flow system excited by argon-ion and helium-neon laser radiation. The full-width at half-maximum, position, and intensity of fluorescence were measured. The full-width at half-maximum (3600 cm−1) was independent of excitation wavelength. At higher energy excitation, the emission maximum was independent of excitation line. At lower energy excitation, the emission maximum varied with the excitation line. The emission intensity dropped by a factor of 6 as the excitation wavelength was varied from 465.8 nm to 514.5 nm. Luminescence was also observed upon excitation at 632.8 nm of this compound dissolved in DMSO. Raman data, obtained from solid polymer suspended in a KBr pellet (rotating sample cell, 488.0 nm excitation, S cm−1 bandpass), revealed broad bands at 1385 cm−1, 1590–1615 cm−1, and 2930 cm−1 superimposed upon a weak fluorescent background. Upon ultraviolet laser excitation (363.8 nm, 5 mW power on the sample, 5 cm−1 bandpass), a single broad band appeared, centered at 1300 cm−1. The difference from visible excitation implies that resonance enhancement from an ultraviolet absorbing chromophore occurred.

Fourier transform infrared spectroscopy of the nitrate radical .nu.2 and .nu.3 bands: absolute line strength measurements

The nitrate radical, NO/sub 3/, was produced in a low pressure (<10 Torr) discharge flow reactor and probed by high-resolution (0.005 cm/sup -1/) Fourier transform infrared spectrometry in the regions 730-780, 1020-1090, and 1470-1520 cm/sup -1/. Two infrared bands, consisting of only K/sup 2/ = 3n (n = integer) transitions, have been observed and are assigned, according to D/sub 3h/ symmetry, to the out-of-plane bend (nu/sub 2/) and to the N-O degenerate stretch (nu/sub 3/). Consistent with this assignment is the absence of a symmetric stretching band. Rovibrational constants are derived from the nu/sub 2/ band (nu/sub 0/ = 762.327 cm/sup -1/). Absolute NO/sub 3/ concentrations, derived from measured absorptions of helium-neon laser radiation (632.8 nm), are used in conjunction with the infrared measurements to determine absolute infrared line strengths. Band strengths for nu/sub 2/ and nu/sub 3/ of 26 +/- 19 and 150 +/- 100 cm/sup -2/ atm/sup -1/ are calculated from the observed line strengths. In addition, an upper limit of 2 cm/sup -2/ atm/sup -1/ is obtained for the band strength of the forbidden symmetric stretch (nu/sub 1/). These observed bands are not sufficiently intense to permit infrared detection of NO/sub 3/ in the terrestrial atmosphere usingmore » currently available techniques.« less

Use of laser for dental hard tissue hyperesthesia

To date, many methods for the treatment of dental hard tissue hyperesthesia have been proposed, but their lack of effectiveness has led to the search for new methods of treatment. We studied the effectiveness of helium-neon laser radiation for dental hyperesthesia not associated with periodontal pathology. We observed 24 patients aged from 34 to 70 years with dental hard tissue hyperesthesia of I to III degree.

Effects of low-watt helium neon laser radiation on human lymphocyte cultures.

Etude des effets du rayonnement laser helium neon sur les lymphocytes. On constate une augmentation de la synthese de collagene. Le mecanisme exact de l'alteration des lymphocytes apres exposition au laser etant peu clair, l'etude s'est limitee a decrire l'augmentation d'ADN suivant cette exposition

Helium-Neon-Laser-Effekt auf Haut und orale Schleimhautgewebe

The biological effects of the helium-neon (He-Ne) laser on skin and oral mucosa were examined for the first time electron microscopically. Canine epidermis, gingiva and sublingual regions were subjected to treatment by the helium-neon laser with varying exposure times. The exposed tissues were excised immediately after radiation and studied with an electron microscope. Depending on the exposure times, ultrastructural alterations were observed such as cytoplasmic vesiculation and vacuolization, mitochondrial changes, dilation of the endoplasmic reticulum, the Golgi cisternae and other endomembranes of the keratinocytes. Furthermore, ultrastructural changes were seen in stromal cells, endothelial cells of the blood and lymphatic vessels, nerves, muscle cells and in the extracellular compartment of the lamina propria. The ultrastructural alterations of different cell and tissue structures following helium-neon laser radiation were compared with the effects induced by other types of lasers. The results are discussed in light of the stimulation of biological cell processes by low-energy lasers.

Quantitative analysis of lymphocyte-Salmonella interaction and effect of lymphocyte irradiation by Helium-Neon laser

A model system has been developed to quantitatively investigate bacteria-cell interaction using a rough mutant of Salmonella and human peripheral blood lymphocytes. The effect of lymphocyte irradiation by low-power continuous wave Helium-Neon laser has been investigated since laser therapy in wound and decoubitous ulcer healing could involve the lymphoyd cell function. Helium-Neon laser irradiation is shown here to enhance the adherence of Salmonella to lymphocytes. In particular, changes in newly defined binding parameters show that laser irradiation increases the frequency of binding-lymphocytes, the affinity of Salmonella for lymphocytes and the number of lymphocyte receptor sites as well.

Erratum: Investigation of changes in the angular divergence of helium-neon laser radiation (λ = 3.39 μ) as a function of the dispersion characteristic of the active medium [Sov. J. Quantum Electron. 14, 1142-1143 (August 1984)

The angular divergence of helium-neon laser radiation was found to depend on variation of the emission frequency within the limits of the gain profile of the active medium. The maximum relative change in the angular divergence was 4 ± 2%. This change appeared because of a nonlinear frequency dependence of the refractive index of the active medium in the region of the Doppler-broadened gain profile. The effect appeared particularly clear in the case of long optical paths.

Investigation of changes in the angular divergence of helium-neon laser radiation (λ= 3.39μ) as a function of the dispersion characteristic of the active medium

The angular divergence of helium-neon laser radiation was found to depend on variation of the emission frequency within the limits of the gain profile of the active medium. The maximum relative change in the angular divergence was 4 ± 2%. This change appeared because of a nonlinear frequency dependence of the refractive index of the active medium in the region of the Doppler-broadened gain profile. The effect appeared particularly clear in the case of long optical paths.

Effect of helium-neon laser radiation on morphology of experimental allergic contact dermatitis

Clinical and morphological studies of guinea-pig skin in the areas of dermatitis induced by application of dinitrochlorobenzene (DNCB) have shown the decreased skin response to DNCB after treatment with helium-neon laser (wave length 632.8 nm, power density 8-10 mvt /cm2). The ultrastructural signs of cell metabolism activation in the epidermis and derma as well as activation of capillary transport have been discovered in allergic contact dermatitis areas after treatment with helium-neon laser.

Effects of laser guided by optic fiber into rat brain on conditioned avoidance response and brain chemistry.

Low power lasers were guided by optic fibers into the rat caudate nucleus or frontal cortex, during conditioned avoidance response (CAR) training. The changes in striatal monoamine and amino acid concentrations were subsequently determined. Of six training groups tested, only the experimental group with helium-neon laser radiation to the caudate nucleus exhibited the formation of CAR and an increase of unconditioned leg contractions. The striatal concentrations of dopamine (DA) and norepinephrine (NE) were increased simultaneously in the group.

Effect of low-power density laser radiation on healing of open skin wounds in rats.

We performed a study to determine whether laser radiation of low-power density would affect the healing of open skin wounds in rats. The wounds were irradiated daily with a helium-neon laser (wavelength, 632.8 nm) and an argon laser (wave-length, 514.5 nm) at a constant power density of 45 mW/sq cm. The rate of wound closure was followed by photographing the wounds in a standardized way. The collagen hydroxyproline concentration in the scar tissue was determined on the 18th postoperative day. Helium-neon laser radiation had a statistically significant stimulating effect on collagen synthesis in the wound, with a maximum effect at an energy density of 4 joules/sq cm. The rate of wound closure was enhanced significantly between the third and 12th postoperative days. The argon laser exposure produced a significant increase in collagen concentration both in irradiated and nonirradiated contralateral wounds. However, an acceleration of the healing rate was not registered in this case. The wound contraction up to the fourth day of the experiment was inhibited under helium-neon and argon laser exposure to 20 joules/sq cm. The described effects were not specific for the laser light. There may be a wavelength-selective influence of coherent light on the metabolic and proliferation processes in wound healing, with the associated problem of the possible carcinogenic effects of laser radiation.

Conversion of the frequency of He–Ne laser radiation fromλ=1.15μto 377.6 nm in thallium vapor

Infrared helium-neon laser radiation (λ = 1.15 μ) was transformed to the ultraviolet range (λ = 377.6 nm) in thallium vapor by parametric mixing with radiation from a rhodamine 6G dye laser (λ = 568.6 nm). Use was made of a two-photon resonance of the pump (dye laser) radiation with the 6P1/2–7P3/2 forbidden transition and of the proximity of the frequency of the radiation being temsformed to the frequency of the 7P3/2–7S1/2 transition.

Spatial modulation of light in a photosensitive structure composed of a liquid crystal and an insulated gallium arsenide crystal

An experimental study was made of photosensitive metal-insulator-semiconductor structures in contact with a nematic liquid crystal. Utilization of the orientational electrooptic effect in the liquid crystal ensured a high energy sensitivity of a structure with gallium arsenide as the semiconductor. Modulation of the phase of light by π or attainment of the highest optical contrast (of the order of 100:1) was achieved when the minimum intensity of the exciting helium-neon laser radiation (λ=633 nm) was 5×10–7 W/cm2 and the switching energy was 10–8–10–9J/cm2. Spatial resolution was at least 10–12 lines/mm. A structure of this kind could be used for coupling in and conversion of optical data, including visualization of infrared radiation.

Influence of the information carrier nonlinearity on the density of information recorded in optical memories

An analysis is made of the influence of the information carrier nonlinearity on the density of information recorded in a discrete manner in optical memories. It is shown that the use of nonlinear and threshold light-sensitive materials as information carriers can increase the recording density and the signal/noise ratio in the reproduction of the recorded information. It is reported that information can be recorded at a density of 108 bit/cm2 by helium-neon laser radiation in a nonlinear light-sensitive material based on a chalcogenide glass.