The experimental action of helium-neon laser radiation on the tracheal and bronchial mucosa

It has been shown that the energy of helium-neonium laser does not affect the tracheal and bronchial mucosa and does not induce tissue irreversible changes under the dose of 358 J/cm2. The sufficient parameters for good treatment are: -4.78 J/cm2, the density of power--7.9 mWt/cm2, the power--0.6 J and time of exposition -1 min.     

Effect of helium-neon laser radiation on the 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.     

Effect of helium-neon laser radiation on the radiosensitivity of Escherichia coli K-12 cells

A study was made of the combined effect of laser radiation (helium-neon laser, lambda = 633 nm) and X-rays on bacteria of different genotypes. The sensitivity of cells to X-rays was decreased by pre- and post-irradiation with laser. In the latter case, the radio-modifying effect of laser was more pronounced.     

Effect of various peptides on the growth of Mycobacterium tuberculosis

Ten oligopeptides containing asparagine, glutamic acid, leucine or alanine on growth of Bacillus tuberculosis were tested. The experiments were performed on AS medium free of peptones. Bacterial suspensions were inoculated and the number of colonies and rapidity of bacilli growth under an influence of peptides tested was compared. Out of peptides studied and their different combinations the best turned to be combination of 0.01% glutathione +0.002% Gly-Asn + 0.0033% Leu-Gly. This combination allowed to appear on average 46% colonies more than on medium without peptides and first growth of tubercle bacilli was seen on average 3.2 days earlier than on medium free of peptides. Addition to the medium containing three above listed peptides of 0.1% of Bacto Tryptone (Difco) caused an increase of 127% of colony number of tubercle bacilli and their growth appeared 1.7 day earlier as compared to growth on medium containing these three peptides.     

Effect of helium-neon laser on wound healing

To estimate the biostimulatory effects of low intensity laser radiation on healing of skin wounds, two linear skin wounds were produced on either side of dorsal midline in rats and immediately sutured. Wounds on the left side were irradiated daily with helium neon laser at 4 Joules/sq.cm for 5 min., while those on right side were not exposed and served as controls. The mean time required for complete closure in control group was 7 days while irradiated test wounds took only 5 days to heal (P < 0.01). The mean breaking strength, as measured by the ability of the wound to resist rupture against force, was found to be significantly increased in the test group. Early epithelization, increased fibroblastic reaction, leucocytic infiltration and neovascularization were seen in the laser irradiated wounds. The results establish the biostimulatory effects of low intensity laser radiation on healing of skin wounds.     

Unique mechanism of action of the thiourea drug isoxyl on Mycobacterium tuberculosis

The thiourea isoxyl (thiocarlide; 4,4'-diisoamyloxydiphenylthiourea) is known to be an effective anti-tuberculosis drug, active against a range of multidrug-resistant strains of Mycobacterium tuberculosis and has been used clinically. Little was known of its mode of action. We now demonstrate that isoxyl results in a dose-dependent decrease in the synthesis of oleic and, consequently, tuberculostearic acid in M. tuberculosis with complete inhibition at 3 microg/ml. Synthesis of mycolic acid was also affected. The anti-bacterial effect of isoxyl was partially reversed by supplementing growth medium with oleic acid. The specificity of this inhibition pointed to a Delta9-stearoyl desaturase as the drug target. Development of a cell-free assay for Delta9-desaturase activity allowed direct demonstration of the inhibition of oleic acid synthesis by isoxyl. Interestingly, sterculic acid, a known inhibitor of Delta9-desaturases, emulated the effect of isoxyl on oleic acid synthesis but did not affect mycolic acid synthesis, demonstrating the lack of a relationship between the two effects of the drug. The three putative fatty acid desaturases in the M. tuberculosis genome, desA1, desA2, and desA3, were cloned and expressed in Mycobacterium bovis BCG. Cell-free assays and whole cell labeling demonstrated increased Delta9-desaturase activity and oleic acid synthesis only in the desA3-overexpressing strain and an increase in the minimal inhibitory concentration for isoxyl, indicating that DesA3 is the target of the drug. These results validate membrane-bound Delta9-desaturase, DesA3, as a new therapeutic target, and the thioureas as anti-tuberculosis drugs worthy of further development.     

The red light of the helium-neon laser reactivates superoxide dismutase

The effect of low-energy helium-neon laser (HNL) on enzymatic activity, absorbtion spectra and electron paramagnetic resonance (EPR) signals of superoxide dismutase (SOD) from bovine erythrocytes in acid medium were investigated. It was found that incubation during 2 hours at pH 5.9 led to eventually complete inactivation of the enzyme. The subsequent illumination of inactivated SOD by HNL brought about the enzyme reactivation. Both absorption and EPR-spectra were changed after incubation at pH 5.9. These changes may be attributed to protonation of histidine residue in the enzyme active site. After laser irradiation both absorption and EPR spectra were restored to those typical of native enzyme at pH 8.2. In a model system, copper-histidine complex, absorption maximum was shifted from 632-633 nm at pH 5.8 to 639-640 nm at pH 8.5-9.0. The similar long-wave length shift of the maximum was observed after illumination by HNL at pH 5.8. It may be postulated that the photoreactivation of SOD consists essentially in deprotonation of His-61 residue in the enzyme active site and subsequent recovery of imidazole bridge between copper and zinc which had been destroyed at low pH. Since many other enzymes possess similar copper-histidine structures in their active sites, one may expect diverse effects of red (laser) light on the enzyme activity.     

Effects of helium-neon laser on physico-chemical properties of the bile

The influence of helium-neon laser radiation on bile physico-chemical characteristics in healthy subjects and in patients with the physico-chemical stage of gallstone disease was studied in vitro. This type of laser was found to induce positive therapeutic effects, such as: correction of hydrogen ion concentrations, surface tension and viscosity decrease and prolonged bile nucleation in patients with gallstone disease.