The biological effects of 632.8-nm low energy He-Ne laser on peripheral blood mononuclear cells in vitro

The aim of this study was to examine the proliferation of peripheral blood mononuclear cells due to the low energy 632.8-nm He-Ne laser application. The results of previous studies supported the hypothesis that low level laser therapy (LLLT) might have an increasing effect on the proliferation of lymphocytes and production of cytokines. The effect of laser irradiation was investigated by comparing the proliferation of peripheral blood mononuclear cells (PBMC) with a mitogenic stimulator, PHA (phytohemaglutinin) and laser irradiation. PBMCs of control samples, only laser irradiated samples, PHA included samples and both PHA included and laser irradiated samples were quantified and compared. Results of [3H] Thymidine test, 20 s laser irradiated and 40 s laser irradiated samples' proliferation were found statistically higher than control samples. There was no significant difference between control and 60 s laser irradiated samples. PHA also showed its ability to proliferate cells. PHA included samples and both PHA included and laser irradiated samples' proliferation was higher than both control and only laser irradiated samples. Our results showed that He-Ne laser application enhanced the proliferation significantly. Moreover, laser dose was noted as a significant parameter. On the other hand, LLLT by itself was found less effective than PHA.     

Effect of Ga-As (904nm) and He-Ne (632.8 nm) laser on injury potential of skin full-thickness wound

Injury potential may have a triggering biological role in wound healing. In this study, the effect of photostimulation to promote wound healing and its effect on injury potential was investigated using the Ga-As and He-Ne lasers. In this study, 30 healthy male Sprague-Dawley rats were randomly divided into a control and two laser groups, He-Ne and Ga-As laser. A 2.5 cm craniocaudal full-thickness skin incision was made on each animal's dorsal region. Differential skin surface potential was measured before and immediately after the injury and also up to the 21st day, every other day. Wound surface area was also measured. Immediately after injury, wound potential significantly increased in all three groups. Maximum positive peak of injury potential was greater in Ga-As group compared to He-Ne laser and control groups (P<0.05) and lasting period of maximum positive potential in two laser groups was longer than that in the control group. There were no significant differences between the mean potential of before wounding and after the 15th, 17th, and 19th day in Ga-As, He-Ne, and control group, respectively (P>0.05). On the other hand, Ga-As and He-Ne laser facilitated the normal distribution of skin potential after wounding. These findings demonstrate that Ga-As laser may be more effective on wound closure and on returning the injury potential to normal level than the He-Ne laser.     

Induction of phr gene expression in E. coli strain KY706/pPL-1 by He-Ne laser (632.8 nm) irradiation

We have observed that He–Ne laser irradiation of E. coli strain KY706/pPL-1 leads to induction of photolyase gene, phr. The magnitude of induction was found to depend on the He–Ne laser fluence, fluence rate and post-irradiation incubation period in the nutrient medium. The optimum values for fluence and fluence rate were 7×10³ J/m² and 100 W/m², respectively, and the induction of phr gene was observed to saturate beyond an incubation period of 2 h. Experiments carried out with singlet oxygen quenchers and with D₂O suggest that the effect is mediated via singlet oxygen. Photoreactivation studies carried out after UVC exposure of both the He–Ne laser-exposed as well as unexposed cells showed a larger surviving fraction in the He–Ne laser pre-irradiated cells. This can be attributed to He–Ne laser irradiation-induced induction of phr expression. However, since even without photoreactivating light He–Ne laser pre-irradiated cells show higher survival against UVC radiation it appears that He–Ne laser irradiation induces both light-dependent as well as dark DNA repair processes.     

A comparative study of laser spray and electrospray

A comparative study of electrospray and laser spray has been undertaken from various aspects. In general, laser spray gave stronger ion signals than electrospray, for solutions with the sample concentration of 相似文献   

A comparative study on gamma irradiation of unconjugated bilirubin in aqueous and non-aqueous solutions

Dilute aqueous and non-aqueous solutions of bilirubin were exposed to gamma radiation to examine the effects of ionizing radiation on the concentrations of a specimen of this nature. The ionising radiation emanated from a (137)Cs source, and was applied to 5.2 x 10(-2) mmol L(-1) solutions of the unconjugated specimen in 0.05 mol L(-1) aqueous NaOH and chloroform. Depletion of bilirubin after exposure was common to both solvents. Complete degradation was accomplished with doses in excess of 100 Gy. In the case of NaOH, it was found that the presence of molecular oxygen contributed more efficiently to the degradation process, than irradiation in air. When the experimental conditions were changed to nitrogen, the degradation process was suppressed. The sole by-product of merit originating from the NaOH work was the short-wavelength isomer of biliverdin, at 330 nm. In the case of chloroform, the exclusive product of interest was characterised as the long-wavelength isomer of biliverdin that absorbs in the broad region commencing from about 620 nm. The non-aqueous study was conducted in the presence and absence of molecular oxygen, with no significant changes in the results. Optimum production of the isomers in question occurred at a gamma dose of about 80 Gy. The general species of interest were monitored spectrophotometrically, and the results were treated mathematically to facilitate evaluation of the data. Our work represents the development of a facile gamma-ray method for the exclusive production of specific isomers of biliverdin, which are useful components in biosynthetic research.     

Induction of phr gene expression in E. coli strain KY706/pPL-1 by He–Ne laser (632.8 nm) irradiation

We have observed that He–Ne laser irradiation of E. coli strain KY706/pPL-1 leads to induction of photolyase gene, phr. The magnitude of induction was found to depend on the He–Ne laser fluence, fluence rate and post-irradiation incubation period in the nutrient medium. The optimum values for fluence and fluence rate were 7×10³ J/m² and 100 W/m², respectively, and the induction of phr gene was observed to saturate beyond an incubation period of 2 h. Experiments carried out with singlet oxygen quenchers and with D₂O suggest that the effect is mediated via singlet oxygen. Photoreactivation studies carried out after UVC exposure of both the He–Ne laser-exposed as well as unexposed cells showed a larger surviving fraction in the He–Ne laser pre-irradiated cells. This can be attributed to He–Ne laser irradiation-induced induction of phr expression. However, since even without photoreactivating light He–Ne laser pre-irradiated cells show higher survival against UVC radiation it appears that He–Ne laser irradiation induces both light-dependent as well as dark DNA repair processes.     

Biostimulation of dermal fibroblast by sublethal Q-switched Nd:YAG 532 nm laser: collagen remodeling and pigmentation

The application of medical lasers in treating pigmented lesions has rapidly developed over the past decade. In both clinical and cosmetic application, melanin is targeted in pigmented areas and destroyed by the mechanism of selective photothermolysis. When laser radiation passes through superficial pigmented tissue, energy will be further reduced by dermal collagen scattering and absorption. Non-pigmented dermal fibroblasts will be exposed to co-incidental laser irradiation at lower energy levels. Biostimulation of dermal fibroblasts by low energy laser is reported in this paper. The Q-switched frequency doubled Nd:YAG 532nm laser used in clinical laser therapy was used in this study. Sublethal laser fluence was determined at 0.8J/cm(2) and used to stimulate normal human fibroblasts in monolayer culture. The results showed that there was no significant difference in collagen synthesis between the stimulated fibroblasts and controls. However, significant delay in collagen remodeling activity was demonstrated in the irradiated group by measuring fibroblast populated collagen lattice (FPCL) contraction. The stimulation of SCF, HGF and b-FGF gene expression was determined by RT-PCR analysis and demonstrated to vary between cases. Two out of six cell lineages that showed stronger responses to laser stimulation on SCF, HGF and b-FGF gene expressions were used to prepare conditioned media. The conditioned media from irradiated groups showed significant increase in SCF and b-FGF content and stimulated SK-mel-3 melanoma cells to synthesize more melanin in vitro. These results suggest that sublethal laser stimulation of fibroblasts may cause post-laser hyperpigmentation through production of melanogenic stimulatory cytokines. The degree of stimulation of SCF, HGF and b-FGF production varied between individual cell lineages, which may reflect the true variation of post-laser hyperpigmentation in clinical practice.     

Reverse intersystem crossing in rose bengal. II. Fluence dependence of fluorescence following 532 nm laser excitation

A fluence-dependent fluorescence technique was used to observe reverse intersystem crossing from a certain higher-lying triplet state of rose bengal populated by a single pulse of 532 nm light. The quantum yield of reverse intersystem crossing from this state was determined to be 0.12+/-0.02 for rose bengal in phosphate-buffered saline. The importance of including molecular rotation effects in the analysis of fluorescence resulting from reverse intersystem crossing is discussed. Differences in the photochemical reactivity of upper triplet states in biological systems have been previously hypothesized to result from photophysical differences, particularly substantial differences in their reverse intersystem crossing yields. In this work this hypothesis is analyzed quantitatively, using numerical models of the population dynamics. These models suggest that reverse intersystem crossing alone cannot adequately explain the differences in biological response.     

A study of some of the rheological properties of concentrated polystyrene latices

Monodisperse latices form highly ordered but liquid-like structured dispersions at moderate to high concentrations. The rheological measurements show such systems to be viscoelastic. Shear wave propagation and creep compliance measurements have been carried out as a function of volume fraction using polystyrene latices in dilute electrolyte. These measurements enabled the high frequency limiting modulus and the zero shear rate viscosity to be obtained.The data are compared with predictions from models based on the perturbation of ordered particle structures, the magnitude of the particle pair potentials and the restricted diffusive motion of particles in the structures.     

A 193 nm laser photofragmentation time-of-flight mass spectrometric study of chloroiodomethane

The photodissociation dynamics of chloroiodomethane (CH2ICl) at 193 nm has been investigated by employing the photofragment time-of-flight (TOF) mass spectrometric method. Using tunable vacuum ultraviolet undulator synchrotron radiation for photoionization sampling of nascent photofragments, we have identified four primary dissociation product channels: CH2Cl + I(2P(1/2))/I(2P(3/2)), CH2I + Cl(2P(1/2))/Cl(2P(3/2)), CHI + HCl, and CH2 + ICl. The state-selective detection of I(2P(3/2)) and I(2P(1/2)) has allowed the estimation of the branching ratio for I(2P(1/2)):I(2P(3/2)) to be 0.73:0.27. Theoretical calculations based on the time-dependent density-functional theory have been also made to investigate excited electronic potential-energy surfaces, plausible intermediates, and transition structures involved in these photodissociation reactions. The translation energy distributions derived from the TOF measurements suggest that at least two dissociation mechanisms are operative for these photodissociation processes. One involves the direct dissociation from the 2 1A' state initially formed by 193 nm excitation, leading to significant kinetic-energy releases. For the I-atom and Cl-atom elimination channels, the fragment kinetic-energy releases observed via this direct dissociation mechanism are consistent with those predicted by the impulsive dissociation models. Other mechanisms are likely predissociative or statistical in nature from the lower 1 1A' and 1 1A' states and/or the ground X 1A' state populated by internal conversion from the 2 1A' state. On the basis of the maximum kinetic-energy release for the formation of CH2Cl + I(2P(1/2)), we have obtained a value of 53+/-2 kcal/mol for the 0 K bond dissociation energy of I-CH2Cl. The intermediates and transition structures for the CHI + HCl and CH2 + ICl product channels have been also investigated by ab initio quantum calculations at the MP2(full)/6-311G(d) and B3LYP(full)/6-11G(d) levels of theory. The maximum kinetic-energy releases observed for the CHI + HCl and CH2 + ICl channels are consistent with the interpretation that the formation of CHI and CH2 in their ground triplet states is not favored.     

Cytokine production after helium-neon laser irradiation in cultures of human peripheral blood mononuclear cells.

The effects of laser light on the immune system have not been extensively characterized. Low-power laser sources, such as the helium-neon (He-Ne) laser with a wavelength of 632.8 nm, have been found to produce photobiological effects with evidence of interference with immunological functions. We have investigated the effects of He-Ne laser irradiation on Ficoll-Hypaque-isolated human peripheral blood mononuclear cells (PBMC). Cultured cells were irradiated for various times at two selected intensities and then stimulated with different mitogens. The rate of incorporation of 3H-thymidine into the DNA of stimulated cells decreased with increasing energy density. The levels of interleukin-1 alpha (IL-1 alpha), interleukin-2 (IL-2), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in supernatants of the cultures were determined (irradiated either before or after stimulation). When stimulating cells after irradiation, significantly increased levels of all cytokines were detected after 30 min of irradiation (18.9 J cm-2), whereas after 60 min of irradiation (37.8 J cm-2) cytokine levels were found to be significantly decreased.     

A comparative study of some hydroxyanthraquinones as acid-base indicators

Alizarin, Alizarin S, quinizarin and quinalizarin have been compared as acid-base indicators with Bromocresol Green and Methyl Orange as reference indicators. The chromaticity co-ordinates, complementary chromaticity co-ordinates, pK(a) values, transition pH-range, pH of maximum colour change, optimum concentration for titrations and the quality of colour change were determined. The results show all four to be good indicators with a colour change quality similar to that of Bromocresol Green.     

两种医用胶原膜 60Co辐照改性的比较

胶原作为一种新型生物材料,具有无毒,良好的生物相容性,生物可降解性及可吸收性,广泛用于皮肤创伤的治疗、骨缺损的修复、药物缓释的载体、止血敷料、组织工程支架材料等。但胶原在体内降解太快,不能与组织再生速度相匹配。有必要探讨胶原生物材料的改性方法,便于其更好     

Biomodulative effects induced by 805 nm laser light irradiation of normal and tumor cells

The influence of light emitted from a diode laser centred at λ = 805 nm was investigated on murine skeletal myotubes (C2), normal urothelial cells (HCV29), human squamous carcinoma cells of the gingival muscosa (ZMK) and urothelial carcinoma cells (J82) in a computer-controlled irradiation chamber. Cells were treated with varying fluences between 0 and 20 J cm⁻². The response was tested by analysis of the mitotic index using single cell counting after Orcein staining and proliferation index based on BrdU incorporation during DNA synthesis. While the mitotic index of C2, HCV29 and J82 cells increased at a fluence of 4 J cm⁻², irradiation with fluences of 20 J cm⁻² resulted in a slight decrease. ZMK tumor cells showed a decrease of the mitotic index with both fluences. No significant differences could be determined when using irradiances between 10 mW cm⁻² and 150 mW cm⁻². The BrdU test after irradiation showed no significant effects compared to the controls in each cell line.     

A comparative study of some oxygen and sulphur substituted alkyl radicals

Several sulphur containing alkyl radicals have been generated and their ESR spectra and hyperfine coupling constants compared with those of the oxygen analogues. Deviations from planarity are smaller when a tervalent carbon atom is bonded to sulphur than when bonded to oxygen. Moreover greater delocalization of the unpaired electron is apparent in the sulphur radicals and this leads to higher barriers to internal rotation in radicals of the form H₂SR compared with H₂OR.     

Two-quantum photoprocesses in DNA under picosecond laser UV irradiation at 216 and 270 nm.

It is demonstrated that at high power picosecond laser irradiation of 216 and 270 nm, two-quantum photodestructions of the DNA secondary structure, such as interstrand covalent crosslinks, "weak" crosslinks, and B----C conformational transition, take place. Thermal effects do not contribute to the observed effects.     

A comparative study on the thermal decomposition of some transition metal carboxylates

Thermal decomposition of transition metal malonates, MCH₂C₂O₄?xH₂O and transition metal succinates, M(CH₂)₂C₂O₄?xH₂O (M=Mn, Fe, Co, Ni, Cu, Zn) has been studied employing TG, DTG, DTA, XRD, SEM, IR and Mössbauer spectroscopic techniques. After dehydration, the anhydrous metal malonates and succinates decompose directly to their respective metal oxides in the temperature ranges 310–400 and 400–525°C, respectively. The oxides obtained have been found to be nanosized. The thermal stability of succinates have been found to be higher than that of the respective malonates.     

The effect of green laser light irradiation on whole blood platelets

BACKGROUND: Laser light irradiation is assumed to have biostimulating effect in various cell types. However, there is still a lack of information concerning response of blood platelets to laser light irradiation. METHODS: In our study we used flow cytometry to monitor the effect of a green Nd-YAG laser (532 nm, 30 mW) irradiation on platelet activation and the expression of activated GPIIbIIIa glycoprotein complex (fibrinogen receptor) of whole blood platelets stained with fluorolabelled monoclonal antibody PAC-1. Also the formation of platelet microparticles and aggregates in a population of whole blood platelets following such irradiation was evaluated. RESULTS: Effects of laser light on platelet activation and reactivity were significant over a wide range of applied energies (p<0.01). While low and medium laser light energies (18 and 54 J) increased platelet activation, the irradiation with a high-energy laser light (108 J) resulted in depressed platelet reactivity and attenuated platelet response to activators. In addition, laser light irradiation had significant influence on the formation of platelet microparticles in either resting (p<0.05) or ADP-activated (p<0.05) platelets, while no significant effect was observed in collagen-activated platelets. On the other hand, laser light irradiation significantly increased the formation of platelet aggregates both in resting (p<0.01) and agonists-activated (p<0.05) platelets. CONCLUSIONS: Our results clearly point that the laser light irradiation of blood platelets can trigger signal transduction, leading to platelet activation, as well as the gradual loss of natural platelet reactivity and platelets' ability to respond to activating agents.     

A copper vapour laser operating at wavelengths of 303.6 nm and 306.3 nm

A commercial copper vapour laser has been modified to operate at wavelengths of 303.6 nm and 306.3 nm. The laser transition at 578 nm was suppressed, in order to enhance the competing U.V. transitions. The time averaged U.V. output power level is a few mW's at an electrical input power of up to 4.5 kW. The duration of the pulses is 68 ns.     

A comparative ab initio study of some molecular systems based on hydrazine and formamide

A series of ab initio calculations has been performed on formamide and its hydrogen bonded dimer, s-diformylhydrazine, s-dimethylhydrazine and hydrazine. All systems were assumed planar. The CO, CN and NN bond lengths were optimized in all cases, in order to study the changes of these bonds with variations in the environment. Gross atomic populations and force constants were also considered, and in some calculations the effect of basis enlargements was studied. Significant changes were found in the formamide unit upon dimerization via hydrogen bonds or a NN bond. And, also, a systematic variation was found for the NN bond by going from hydrazine via dimethylhydrazine to diformylhydrazine. The results of this study indicate that the effect of substitution within the framework used is well simulated by ab initio calculations.