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PubMed1991

[The action of helium-neon laser radiation on the growth of Mycobacterium tuberculosis].

The growth properties of M. tuberculosis subjected to the action of helium-neon laser radiation was studied. Laser radiation was shown to change the quantitative and qualitative composition of mycobacterial population. Disturbances in the viability of mycobacteria appear as a consequence of changes in the morphological structure of mycobacterial cells. The maximum effect of helium-neon laser radiation was achieved after the irradiation of M. tuberculosis culture on days 2-3 after inoculation. These results made it possible to suggest that the effect of helium-neon laser radiation was most pronounced in cells at the stage of mitosis (the logarithmic stage of growth) with the highest degree of metabolism.

Colony Count, Microbial↗
PubMed1989

[Morphological and functional changes in the rat ovary under exposure to a helium-neon laser].

The authors studied the occurring morphological and functional changes in the ovaries of mature rats after transcutaneous irradiation with helium-neon laser over the hypogastric region. Density of power of 1.5 mW/ml with exposition time of 1 min and dimensions of irradiation of 16.61 ml was used. The results from the study showed that helium-neon laser, used for a period of incomplete estrous cycle (4 days), stimulated estrogen function of ovaries, manifested with prolongation of the stages of proestrus and estrus. The action for a period of two incomplete estrous cycles stimulated the ovarian endocrine function to a lesser degree, but induced dystrophic changes and ovarian hemorrhages. The indicated morphological and functional changes were established up to the third estrous cycle after the finished irradiation with helium-neon laser.

Animals↗
PubMed1995

Helium-neon laser effects on conditioning-induced oral mucositis in bone marrow transplantation patients.

BACKGROUND: Oral mucositis is a common complication of bone marrow transplantation (BMT) conditioning therapy. Sequelae consist of increased risk for infection, moderate to severe pain, compromised oral function, and bleeding. This study investigated helium-neon laser treatment for prevention of conditioning-induced oral mucositis in BMT patients. Patterns and severity of mucositis for specific conditioning drug regimens also were analyzed. METHODS: Twenty patients received laser radiation to their oral mucosa, either left or right of midline. The contralateral side was sham-treated and served as a control. Mucositis severity was scored independently by two modified versions of the Oral Mucositis Index Scale (OMI-A and OMI-B) and the Eastern Cooperative Oncology Group (ECOG) Oral Toxicity Scale; pain severity was scored by subjects on a visual analogue scale (VAS). Cumulative scores were analyzed for differences between the laser-treated and sham-treated sides. RESULTS: Oral mucositis and pain scores were significantly lower for the treated versus the untreated side by OMI-A and B (P < 0.005) and VAS (P = 0.027) criteria, respectively. Ulcerative lesions occurred in all patients bilaterally; severity increased until Day +6, and lesions resolved by Day +21. Mucositis was more severe for patients conditioned with busulfan/carboplatin/thiotepa than for patients conditioned with busulfan/cyclophosphamide/etoposide. CONCLUSIONS: Helium-neon laser treatment was well-tolerated and reduced the severity of conditioning-induced oral mucositis in BMT patients.

Adult↗
PubMed1980

A new radioisotope for lung ventilation studies: 19-neon.

Neon 19, 17-second positron-emitting radioelement, is produced continuously by 23MeV alpha particle bombardment of oxygen. For a 12 muA particle current the method of preparation described delivers 14 mCi of neon 19 per min to the functional exploration room. The radiochemically pure radioactive gas is diluted in air and breathed continously by the patient lying under a positron tomographic camera. The regional lung ventilation distribution is obtained on 2 cm thick sections of organ with a transverse resolution of 17 mm. Quantification of the ventilation output per unit lung volume is contemplated.

Heart Ventricles↗
PubMed1995

[Neon-colored plastics for orthodontic appliances. Biocompatibility studies].

Public concern and issues of liability have made product safety a major concern throughout the medical field including orthodontics. The purpose of this study was to test the biocompatibility of the new neon colored plastic materials to be used for removable orthodontic appliances before they reach the market and are used in patient treatment. In addition, eight modifications of this synthetic material, which has been used in appliances for many years, were examined without neon color. The procedures established tested for: 1. mutagenicity, 2. toxicity, and 3. irritation of the mucous membrane. As alternatives to using animals the Ames Test, the Agar Overlay Assay, and the HET-CAM Test were employed to test for these properties. The tests revealed that, when the manufacturer's instructions are followed, neither the polymerized materials as used in patient appliances nor the shavings resulting from the orthodontist or the technician grinding the appliance exhibit mutagenic, toxic, or irritating properties.

Animals↗
PubMed1985

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 lymphoid 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.

Binding Sites↗
PubMed1990

Electrophysiologic recording and thermodynamic modeling demonstrate that helium-neon laser irradiation does not affect peripheral Adelta- or C-fiber nociceptors.

The effect of helium-neon laser irradiation (632.5 nm) on A delta- and C-fiber sensory afferents was investigated in the rabbit cornea, to determine the physiologic basis for reports that low power (0.1-5 mW) helium-neon (He-Ne) lasers produce acute analgesia and alleviate chronic pain. Multiple and single unit extracellular recordings from nociceptive corneal afferent nerves (C-fiber cold, C-fiber chemical, A delta mechanical and A delta bimodal) were used to study the effects of He-Ne laser radiation upon the electrophysiologic responses to mechanical, thermal, chemical and electrical stimulation of the cornea. Action potentials were analyzed for latency, amplitude, rise time, duration and frequency. Exposure of the neural receptive field and/or nerve bundle to a 4-mm diameter He-Ne laser (0-5 mW; 0-1800 sec) did not alter spontaneous or evoked neural activity. In addition, single unit action potential parameters were not altered by laser irradiation. Modeling of thermal changes produced by He-Ne radiation on corneal nerves indicated that effects predicted for receptor and axonal depths in both skin and cornea were minimal (less than 0.15 degrees C) and unlikely to alter sensory transduction or transmission.

Afferent Pathways↗
PubMed1996

Measurement of intracellular dna double-strand break induction and rejoining along the track of carbon and neon particle beams in water.

PURPOSE: The study was aimed at the measurement of effect-depth distributions of intracellularly induced DNA damage in water as tissue equivalent after heavy ion irradiation with therapy particle beams. METHODS AND MATERIALS: An assay involving embedding of Chinese hamster ovary (CHO-K1) cells in large agarose plugs and electrophoretic elution of radiation induced DNA fragments by constant field gel electrophoresis was developed. Double-strand break production was quantified by densitometric analysis of DNA-fluorescence after staining with ethidium-bromide and determination of the fraction of DNA eluted out of the agarose plugs. Intracellular double-strand break induction and the effect of a 3 h rejoining incubation were investigated following irradiation with 250 kV x-rays and 109 MeV/u carbon- and 295 MeV/u neon-ions. RESULTS AND CONCLUSION: While the DNA damage induced by x-irradiation decreased continuously with penetration depth, a steady increase in the yield of double-strand breaks was observed for particle radiation, reaching distinct maxima at the position of the physical Bragg peaks. Beyond this, the extent of radiation damage dropped drastically. From comparison of DNA damage and calculated dose profiles, relative biological efficiencies (RBEs) for both double-strand break induction and unrejoined strand breaks after 3 h were determined. While RBE for the induction of DNA double-strand breaks decreased continuously with penetration depth, RBE maxima greater than unity were found with carbon- and neon-ions for double-strand break rejoining near the maximum range of the particles. The method presented here allows for a fast and accurate determination of depth profiles of relevant radiobiological effects for mixed particle fields in tissue equivalent.

Animals↗
PubMed1997

Neon heavy charged particle radiotherapy of glioblastoma of the brain.

PURPOSE: High-linear energy transfer (LET) radiation beams have potential applications in the treatment of glioblastoma, but have not yet demonstrated significant improvement in results. However, some patients have had local control of glioblastoma with high-LET irradiations such as neutrons and heavy charged particles. METHODS AND MATERIALS: In this collaborative study, 15 patients were entered into a randomized protocol comparing two dose levels of 20 and 25 Gy in 4 weeks of neon ion irradiation. This trial was intended to determine the optimal neon dose in terms of survival and effects of radiation. RESULTS: Fourteen patients were evaluable with no significant differences in median survival (13 and 14 months; p = NS) or median time to failure (7 and 9 months; p = NS) between the two dose arms. Three patients died of nontumor-related causes, of whom one (who died 19 months posttreatment) had autopsy confirmation of no tumor on pathological exam. The other two patients had stable magnetic resonance imaging scans at 6 and 22 months posttreatment. CONCLUSION: Although the results did not demonstrate the optimal high-LET dose level, there is an intriguing effect in that two patients had control of glioblastoma until death at 19 and 22 months. This suggests that better conformation of the high-LET dose to the tumor with neutron capture therapy or dynamic conformal heavy charged particle therapy might control glioblastoma while minimizing brain damage from radiation.

Adult↗
PubMed1997

Low energy Helium-Neon laser in the prevention of oral mucositis in patients undergoing bone marrow transplant: results of a double blind randomized trial.

PURPOSE: To evaluate the efficiency of Helium-Neon (He-Ne) laser in the prevention of oral mucositis induced by high dose chemoradiotherapy before autologous bone marrow transplantation (BMT). METHODS AND MATERIALS: Between 1993 and 1995, 30 consecutive patients receiving an autologous peripheral stem-cell or bone marrow transplant (BMT) after high dose chemoradiotherapy were randomized to possibly receive prophylactic laser to the oral mucosa after giving informed consent. Chemotherapy consisted of cyclophosphamide, 60 mg/kg intravenously (I.V.) on day (d)-5 and d-4 in 27 cases, or melphalan 140 mg/kg I.V. on d-4 in three cases. Total body irradiation (TBI) consisted of 12 Gy midplane dose in six fractions (4 Gy/day for three days). He-Ne laser (632.8 nm wavelength, power 60 mW) applications were performed daily from d-5 to d-1 on five anatomic sites of the oral mucosa. Oral examination was performed daily from d0 to d + 20. Mucositis was scored according to an oral exam guide with a 16 item scale of which four were assessed by the patients themselves. Mean daily self assessment scores for oral pain, ability to swallow and oral dryness were measured. A daily mucositis index (DMI) and a cumulative oral mucositis score (COMS) were established. Requirement for narcotics and parenteral nutrition was recorded. RESULTS: The COMS was significantly reduced among laser treated (L+) patients (p = 0.04). The improvement of DMI in L+ patients was also statistically significant (p < 0.05) from d + 2 to d + 7. Occurrence and duration of grade III oral mucositis were reduced in L+ patients (p = 0.01). Laser applications reduced oral pain as assessed by patients (p = 0.05) and L+ patients required less morphine (p = 0.05). Xerostomia and ability to swallow were improved among the L+ patients (p = 0.005 and p = 0.01, respectively). Requirement for parenteral nutrition was not reduced (p = NS). CONCLUSION: Helium-Neon laser treatment was well tolerated, feasible in all cases, and reduced high dose chemoradiotherapy-induced oral mucositis. Optimal laser treatment schedules still needs to be defined.

Adolescent↗
PubMed1981

Misonidazole enhancement of radiation-induced growth delay in rat rhabdomyosarcoma tumours exposed to accelerated carbon and neon ions.

The response of a rat rhabdomyosarcoma tumour was assessed by measurements of radiation-induced growth delay resulting from administration of the hypoxic cell sensitizer misonidazole in combination with single and fractionated doses of X-rays and charged-particle radiation. Enhancement ratios of 1.8--2.1 were obtained following single doses of misonidazole (500 mg/kg i.p.) and 225 kV X-rays. Single doses of misonidazole with either carbon-ion or neon-ion radiation in the 4 cm extended-peak ionization region led to enhancement ratios of 1.2--1.3. When combined misonidazole (300 mg/kg i.p.) and X-ray treatments were given in four daily fractions, the enhancement ratios decreased to 1.2--1.5. However, a four-fraction schedule using either carbon-ion or neon-ion radiation in combination with misonidazole gave enhancement ratios of 1.1--1.3, which are similar to the values obtained for single-dose schedules with the sensitizer and charged-particle radiation.

Animals↗
PubMed1989

Effects of helium-neon laser irradiation on skin resistance and pain in patients with trigger points in the neck or back.

The purpose of this double-blind study was to ascertain the effects of helium-neon (He-Ne) laser irradiation on skin resistance and pain in patients with trigger points in the neck or low back. This study entailed a partial replication of a previous study by Snyder-Mackler and associates that determined the use of the He-Ne laser increased skin resistance overlying a trigger point. Twenty-four patients were randomly assigned to either a treatment or a control group and received three 20-second applications of laser irradiation or placebo "stimulation," respectively. Pretreatment and posttreatment skin resistance and pain measurements (via visual analog scale) were taken during each session. Results indicated a statistically significant increase in skin resistance (p less than .001) and a decrease in pain (p less than .005) following laser treatment. There was not a significant correlation between skin resistance and pain across subjects. These data substantiate the previous findings of Snyder-Mackler and associates and demonstrate a reduction in pain. Helium-neon laser treatment, therefore, may be an effective adjunct to conventional physical therapy of these patients.

Double-Blind Method↗
PubMed1987

Biostimulation of wound healing in vivo by a helium-neon laser.

Clinical observations have suggested that low-energy lasers might stimulate wound healing. To understand the mechanism of the biostimulation, we previously examined the effects of low-energy lasers on collagen production by human skin fibroblasts and reported an increase of collagen synthesis in vitro. To examine the effects of low-energy lasers in vivo, hairless mice were experimentally wounded, sutured, and subjected to laser irradiation by a helium-neon laser with a power output of 1.56 mW and an energy fluence of 1.22 Joules/cm2. Experimental wounds were subjected to laser treatment every other day for 2 months; control wounds remained untreated. Specimens from the wounds were then examined for histological findings, tensile strength, and total collagen content. Results demonstrated a considerable improvement in the tensile strength of the laser-irradiated wounds at 1 and 2 weeks. Furthermore, the total collagen content was significantly increased at 2 months when compared with control wounds. These results suggest a beneficial effect of the helium-neon laser on wound healing in vivo.

Animals↗
PubMed2004

Effects of helium-neon laser on levels of stress protein and arthritic histopathology in experimental osteoarthritis.

OBJECTIVE: To investigate the effect of low-power laser therapy on levels of stress proteins (SPs) in experimental arthritis and their relation to the bioeffects on arthritic cartilage repair. DESIGN: A total of 42 rats with similar degrees of induced arthritis evaluated by means of bone scan were divided randomly into two groups. In the treated group, 21 rats received helium-neon laser treatment; in the control group, 21 rats received sham laser treatment. The changes in chondrocytes of SPs were measured by electrophoresis of proteins extracted from chondrocytes of arthritic cartilage at various time periods. The histopathologic changes and the presence of SP of arthritic cartilage were identified by hematoxylin and eosin stain and by immunostains of SP72 antibody individually from frozen sections of arthritic cartilage. RESULTS: SP density increased markedly in rats after laser treatment and was closely related to the repair of arthritic cartilage. Furthermore, the pathohistology of arthritic cartilage improved significantly with the decline of SP levels in the follow-up period. CONCLUSION: Helium-neon (632 nm) low-power laser can enhance SP production in arthritic chondrocytes. The extragenic production of SP is well correlated with the therapeutic effect of low-power laser in preserving chondrocytes and the repair of arthritic cartilage in rats.

Animals↗
PubMed1967

Animals at very high pressures of helium and neon.

At pressures up to 125 atmospheres, helium failed to anesthetize mice; at slightly higher pressures (135 to 145 atmospheres) it proved lethal. With Italian newts (Triturus italicus), whose sensitivity to anesthesia by nitrogen is similar to that of mice, responsiveness was lost at pressures between 165 and 245 atmospheres, whether the pressure was achieved with helium or neon, or hydrostatically. It was concluded that the anesthetic pressures of helium and neon, for mice and newts, are higher than the tolerable mechanical pressures.

Anesthetics↗
PubMed1976

The relative biological effectiveness (RBE) and oxygen enhancement ratio (OER) of neon ions for the EMT6 tumor system.

EMT6 tumors were exposed to neon ions in vivo and in vitro in the plateau and spread-out Bragg peak regions of the beam. The RBE in vivo was 1.7-2.1 in the plateau region and 2.6-2.9 in the Bragg peak; the OER was 2.0 and 1.4, respectively. Neon ions have great potential in the radiotherapy of tumors because of their decreased OER and excellent depth-dose distribution in tissue.

Animals↗
PubMed2007

Initial yields of DNA double-strand breaks and DNA Fragmentation patterns depend on linear energy transfer in tobacco BY-2 protoplasts irradiated with helium, carbon and neon ions.

The ability of ion beams to kill or mutate plant cells is known to depend on the linear energy transfer (LET) of the ions, although the mechanism of damage is poorly understood. In this study, DNA double-strand breaks (DSBs) were quantified by a DNA fragment-size analysis in tobacco protoplasts irradiated with high-LET ions. Tobacco BY-2 protoplasts, as a model of single plant cells, were irradiated with helium, carbon and neon ions having different LETs and with gamma rays. After irradiation, DNA fragments were separated into sizes between 1600 and 6.6 kbp by pulsed-field gel electrophoresis. Information on DNA fragmentation was obtained by staining the gels with SYBR Green I. Initial DSB yields were found to depend on LET, and the highest relative biological effectiveness (about 1.6) was obtained at 124 and 241 keV/microm carbon ions. High-LET carbon and neon ions induced short DNA fragments more efficiently than gamma rays. These results partially explain the large biological effects caused by high-LET ions in plants.

Animals↗
PubMed2004

Effect of low-power helium-neon laser irradiation on 13-week immobilized articular cartilage of rabbits.

Influence of low-power (632.8 nm, Helium-Neon, 13 J/cm2, three times a week) laser on 13-week immobilized articular cartilage was examined with rabbits knee model. Number of chondrocytes and depth of articular cartilage of experimental group were significantly higher than those of sham irradiated group. Surface morphology of sham-irradiated group had rough prominences, fibrillation and lacunae but surface morphology of experimental group had more similarities to control group than to sham irradiated group. There were marked differences between ultrastructure features of control group and experimental group in comparison with sham irradiated group. Low-power Helium-Neon laser irradiation on 13-week immobilized knee joints of rabbits neutrilized adverse effects of immobilization on articular cartilage.

Animals↗