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At least 163 records · Page 9Linked to original sources
PubMed1980

[Effect of helium-neon laser rays on the process of postradiation recovery in skeletal muscle tissues].

Three series of experiments were conducted on the gastrocnemius muscle of rats. In the first series the entire muscles were autografted. In the second series autografting of the muscles was preceeded by irradiation of both hind limbs at a dose of 1000 R. In the third series x-ray irradiation at the limbs with helium-neon laser whereupon the muscles were autografted. The transplantation regeneration was studied histologically after 2 weeks, one and two months. It was established that exposure to laser stimulates cell reparation in the skeletal muscle tissues and makes post-traumatic regeneration depressed by x-rays return to normal.

Animals↗
PubMed1995

Killing and mutation of Chinese hamster V79 cells exposed to accelerated oxygen and neon ions.

Mutation induction by accelerated heavy ions to 6-thioguanine resistance (HPRT system) in Chinese hamster V79 cells was investigated using oxygen and neon ions with energies between 1.9 and 400 MeV/mu, corresponding to LET values between 18 and 754 keV/microns, respectively. Because of technical limitations most experiments could be performed only once. Inactivation and mutation induction cross sections, sigma i and sigma m, were obtained from the slopes of the exponential survival and the linear mutation induction curves, respectively. Both parameters increased with LET up to about 200 keV/microns, where the curves separated for the two types of ions. Calculated RBEs were higher for mutation induction than for killing for all LET values.

Animals↗
PubMed1994

Increase in <--H+/e- ratio of the cytochrome c oxidase reaction in mitochondria irradiated with helium-neon laser.

In order to gain a degree of insight into the mitochondrial component/s responsible of the mitochondria-red light interaction, isolated rat liver mitochondria were irradiated with a Helium-Neon laser (energy dose 2 Joules/cm2, light power 10 mW) and measurements made of the activity of cytochrome c oxidase. A low, but statistically significant increase in the oxygen uptake was found, as polarographically measured, in the presence of rotenone and antimycin A, with ascorbate and TMPD used as substrate pair. Measurements were also made both of the electron transfer and of proton pumping activity: as a result of a major stimulation in the proton pumping activity, about 55% increase of <--H+/e- ratio was found in irradiated mitochondria.

Animals↗
PubMed1993

Absorbance measurement with a helium-neon laser for chemical dosimetry.

A laser-based system for absorbance measurement has been developed for use in chemical dosimetry as an alternative to the spectrophotometer. The system incorporating a Helium-Neon laser operating at 543.5 nm is designed specifically for measurement of absorbed doses below 10 Gy with the ferrous sulphate-benzoic acid-xylenol orange (FBX) dosimeter. Absorbance measurement for the FBX dosimeter is normally carried out at 540 nm with a spectrophotometer. The performance of the laser-based system in measurement of absorbance is comparable to that of a standard spectrophotometer and it is concluded that the absorbance measurement technique is not the limiting factor in the sensitivity of the FBX dosimeter for absorbed doses below 1 Gy.

Absorption↗
PubMed1983

Immunofluorescence measurement in a flow cytometer using low-power helium-neon laser excitation.

Helium-neon lasers are economical and efficient light sources; their utility in flow cytometry to date has been limited by the lack of fluorescent probes that can be excited at 633 nm. Allophycocyanin (APC), a highly fluorescent phycobiliprotein, can be used as an antibody label and has spectral characteristics suitable for use with He-Ne lasers; we undertook to resolve whether a low-power (7 mW) He-Ne laser could provide sufficient excitation to permit flow cytometric detection of APC-labeled antibodies on cell surfaces. We made an APC conjugate of monoclonal antibody 4F2, which reacts with an antigen abundant on the surfaces of activated human T-lymphocytes; APC-4F2 was used to stain blood mononuclear cells that had been cultured with and without phytohemagglutinin (PHA). Cells so stained were examined in a flow cytometer with orthogonal illumination at 633 nm from a 7 mW He-Ne laser; antibody-bearing cells were detectable by fluorescence emission above 665 nm. Cells from the same cultures were stained with fluorescein-labeled 4F2 antibody and examined in a flow cytometer with argon ion laser excitation at 488 nm. Percentages of antibody-bearing cells determined from APC fluorescence and from fluorescein fluorescence were in good agreement. It thus appears that He-Ne lasers and APC-antibodies are usable for immunofluorescence measurements; the sensitivity attainable with this technique remains to be determined.

Animals↗
PubMed1987

Comparison of helium-neon and dye lasers for the excitation of allophycocyanin.

Allophycocyanin (APC) has a broad absorption spectrum permitting several different lasers to be used to excite this dye in a flow cytometer. A comparison was made between a dye laser and a helium-neon (HeNe) laser for the excitation of APC as an immunofluorescent chromophore. The ratio of fluorescence of stained to unstained lymphocytes (signal to background) was used to assess differences in sensitivity. In determining the best wavelength for operating the dye laser, it was found that there was little difference in the ability to separate the positive-labelled cells from the unstained cells using 600 nm or 633 nm light for excitation of APC. A study of the effect of laser power on the signal to background identified a nonlinear relationship. It was found that the sensitivity obtained with 47 mW of 633 nm light from a HeNe laser was near the maximum attainable. This sensitivity was comparable to that obtained using phycoerythrin as an immunofluorescence chromophore. APC had the added advantage of being applicable to the study of highly autofluorescent cells. Exciting this chromophore using red light dramatically decreased the autofluorescence observed even on alveolar macrophages.

Animals↗
PubMed1988

Does low-energy helium-neon laser irradiation alter "in vitro" replication of human fibroblasts?

Cultured human fibroblasts were treated in a controlled, randomized manner to assess the effect of low-energy (0.9 mW) helium-neon (HeNe) laser irradiation on cellular proliferation. Two trials were performed: one with fibroblasts in the third to fourth passage and the other with fibroblasts in the 13th to 14th passage. In each trial, separate plastic petri dishes were inoculated with the cells, maintained in a 5% CO2-95% air atmosphere, and nourished with HB 102 media. Treatment began 48 h after inoculation with daily 60-s irradiations of the "treated" cultures over a 5-d period. Control cultures underwent the same handling but were not irradiated. A significant stimulative, or inhibitive, effect on replication was not found in either trial.

Cell Division↗
PubMed1989

Effect of helium-neon and infrared laser irradiation on wound healing in rabbits.

We examined the biostimulating effects of helium-neon laser radiation (HeNe; 632.8 nm), pulsed infrared laser radiation (IR; 904 nm), and the two combined on skin wound healing in New Zealand white rabbits. Seventy-two rabbits received either 1) no exposure, 2) 1.65 J/cm2 HeNe, 3) 8.25 J/cm2 pulsed IR, or 4) both HeNe and IR together to one of two dorsal full-thickness skin wounds, daily, for 21 days. Wound areas were measured photographically at periodic intervals. Tissue samples were analyzed for tensile strength, and histology was done to measure epidermal thickness and cross-sectional collagen area. Significant differences were found in the tensile strength of all laser-treated groups (both the irradiated and nonirradiated lesion) compared to group 1. No differences were found in the rate of wound healing or collagen area. Epidermal growth was greater in the HeNe-lased area compared to unexposed tissue, but the difference was not significant. Thus, laser irradiation at 632.8 nm and 904 nm alone or in combination increased tensile strength during wound healing and may have released tissue factors into the systemic circulation that increased tensile strength on the opposite side as well.

Animals↗
PubMed1990

Does low-intensity helium-neon laser irradiation alter sensory nerve active potentials or distal latencies?

The effect of 1 mW helium neon continuous-wave (0.633 microns) laser irradiation on superficial radical sensory and median sensory nerve function was examined in a double-blind, controlled study involving 40 volunteers. No differences in action potential amplitudes, distal latencies, or forearm skin temperatures were found between the treated and control groups either at the time of irradiation or at subsequent evaluations 15 and 30 minutes later. As a result, we are unable to confirm reports that low-energy lasers of this power and wavelength alter nerve function.

Action Potentials↗
PubMed1990

Helium-neon laser irradiation inhibits the growth of kidney epithelial cells in culture.

We have investigated the in vitro action of helium-neon (He-Ne) laser light on the cell cycle and the growth of rat kidney epithelial cell cultures. Dose-response studies showed that repeated He-Ne irradiation (dose rate 40 mW/cm2) once a day in a dose range between 11.9 and 142 J/cm2 significantly inhibited cell growth, while daily irradiation with 4.7 J/cm2 had no effect. Microscopic examination of nuclear spreads revealed an increased number of cells in mitosis after a single irradiation with 142 J/cm2. These results support previous observations suggesting that laser light of low thermal energy interferes with cell cycling and may inhibit cell growth when irradiation is performed at doses of 11.9 J/cm2 or more.

Animals↗
PubMed2002

Uptake of copper complexed to EDTA, diaminoethane, oxalic acid, or tartaric acid by neon tetras (Paracheirodon innesi).

Uptake of copper complexes by fish was studied by exposing neon tetras (Paracheirodon innesi) to solutions containing different concentrations of copper complexed to EDTA, diaminoethane, oxalic acid, or tartaric acid, while other copper species were kept at low and constant levels. The distribution of the copper species in the solution was quantified using chemical equilibrium modeling. It was found that the presence of the organic ligands studied could reduce, but not totally eliminate, the uptake of copper by fish. The rate of the additional uptake besides the contribution of free copper depended on the conditional stability constant of the copper complexes.

Animals↗
PubMed2000

Effect of helium-neon laser on activity and optical properties of catalase.

The effects of laser (632.8 nm) on functional and spectral properties of catalase at pH 6.0-7.4 were studied. Laser irradiation led to photoactivation of the enzyme at pH 7.1-7.4. Changes in the spectral properties of photomodified hemoprotein were found in the absorption spectrum of the protein component: apoenzyme displayed protective effects in relation to ferroporphyrin. Structural modifications of catalase induced by helium-neon laser irradiation correlated with its functional properties. These results can be used in clinical practice to design the individual management program.

Animals↗
PubMed2002

[Neon--a new angle-stable implant system for dorsal occipitocervical instrumentation. Biomechanical comparison with established systems].

Posterior instrumentation of the occipitocervical spine is well-established for different indications. The aim of this study was to evaluate whether posterior internal fixation of the occipitocervical spine with the new implant system improves primary biomechanical stability. Primary stability was significantly increased in all load cases with the new modular implant system compared to the other implant systems. Pedicle screw instrumentation tended to be stabler compared to lateral mass screws; nevertheless, significant differences could be observed only for lateral bending. As the experimental design precluded any cyclic testing, the data represent only the primary stability of the implants. In summary, this study showed that posterior instrumentation of the cervical spine using the new neon occipito-cervical system improves primary biomechanical stability compared to the CerviFix system and the Olerud cervical rod spinal system.

Aged↗
PubMed1996

Some properties of a microwave boosted glow discharge source using neon as the operating gas.

The use of neon as the operating gas for the analysis of aluminium samples with the microwave boosted glow discharge source has been studied. A new type of anode tube allowed the gas to enter the source near the sample surface so that more material was transported into the discharge. Erosion rates have been measured under conditions optimised for high line-to-background ratios and found to be lower than with argon (9 and 21 n/s, respectively). Despite the lower erosion rate the detection limits measured for a number of elements in aluminium are in the range 0.02-1 microg/g and comparable to those obtained with argon as the operating gas.

Journal Article↗
PubMed1996

Excitation of singly-ionized argon species in helium-matrix Grimm glow discharge plasmas II - Comparison between argon and neon.

A considerable intensity enhancement of several Ar II lines assigned to the 3p(4)4p-3p(4)4s transition in a helium-argon Grimm glow discharge plasma has been previously reported and attributed to argon ions excited by metastable helium atoms. In this paper the behavior of Ne II lines assigned to the 2p(4)3p-2p(4)3s transition in a helium-neon plasma was investigated to obtain detailed information on the excitation of plasma gases in the helium-matrix plasmas. No Ne II lines with enhanced emission intensities have been found; on the contrary, the intensities of the doublet Ne II lines decreased in the helium-matrix plasma.

Journal Article↗
PubMed1984

Dark-induced cone outer segment damage in the neon tetra (Paracheirodon innesi).

The outer segment of the twin cones of the neon tetra show scrolling and vesiculation when exposed to 36 hr of continuous darkness. This disruption first begins as a rolling of the margins of the cone lamellae and proceeds to form a complex pattern of scrolls and vesicles. There is evidence that this damage can be repaired without having to return the animals to a normal light regime. Similar lamellar disruptions have been seen in the outer segments of both rods and cones of other species that have been exposed to various other light regimes including constant light.

Animals↗
PubMed2004

Effects of the endocrine disrupter chemicals chlordane and lindane on the male green neon shrimp (Neocaridina denticulata).

The purpose of this study was to investigate the effect of chlordane and lindane on morphological changes and endocrine disruption in male Green neon shrimp (Neocaridina denticulata). In this experiment, individuals of N. denticulata, a common inhabitant of freshwater systems in Taiwan, were exposed to chlordane (1 and 10 ng/l and lindane (0.1 and 1 microg/l morphological changes and reproductive hormone levels were observed following four weeks exposure. According to our findings, an increase in estrogen, a reduction in testosterone, and morphological alternations of the masculine appendage were observed in both chlordane- and lindane-treated shrimp, while induction of a vitellogenin-like protein appeared only in shrimp treated with 10 ng/l chlordane. An endocrine disruption effect on N. denticulata was demonstrated, and may apply to other organochlorine pesticides or endocrine disruption chemicals.

Animals↗
PubMed2006

Reproduction obstacles for the female green neon shrimp (Neocaridina denticulata) after exposure to chlordane and lindane.

The purpose of this study was to investigate the effects of chlordane and lindane on reproduction obstacles and endocrine disruption in female green neon shrimp (Neocaridina denticulata). Individuals of N. denticulata, a common inhabitant of freshwater systems in Taiwan, was exposed to different levels of chlordane (1 and 10 ngl(-1)) and lindane (0.1 and 1 microgl(-1)). The reproductive ability and reproductive hormone levels were observed after exposure. According to our findings, an increase in estrogen, induction of a vitellogenin-like protein, and changes in reproductive performance were observed in both chlordane- and lindane-treated shrimp. Thus, it was concluded that chlordane and lindane may cause some reproduction obstacles and disruption of endocrine functions in N. denticulata.

Animals↗