P. Chen

Academy of Military Medical Sciences, T’ien-ching-shih, Tianjin Shi, China

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Publications (7)25.61 Total impact

  • Laser Physics Letters 01/2014; 11(1):5002-. · 7.71 Impact Factor
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    ABSTRACT: The continuous wave (CW) laser performance of Nd:GYSGG at 1104 nm is investigated for the first time, to our knowledge. A CW laser output power of 4.7 W is obtained when the pump power of the 808 nm fiber coupled laser diode is 19.1 W, corresponding to a conversion efficiency of 24.6% and slope efficiency of 37%.
    Laser Physics 02/2013; 23(3):035805. · 2.55 Impact Factor
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    ABSTRACT: Restenosis is a major complication after coronary intervention therapy. Excessive proliferation of vascular smooth muscle cells (VSMCs) and a decline in their apoptosis, which eventually leads to excessive neointimal thickening in coronary arteries, are the main causes of restenosis. Induction of the apoptosis of VSMCs and inhibition of excessive proliferation of VSMCs are therefore crucial for the prevention of restenosis, and low-intensity laser irradiation of coronary arteries may play a promising role in keeping this in balance. In this study, we used in vitro cultured rabbit VSMCs to investigate the effects of low-intensity laser irradiation at a wavelength of 532 nm on the apoptosis of VSMCs via morphological observation and molecular biology. The results showed that apoptotic bodies and obvious intranuclear apoptosis-positive particles formed within VSMCs 24 h after laser irradiation, suggesting that low-intensity laser irradiation at certain doses can inhibit the proliferation of VSMCs by promoting their apoptosis. This experiment provides evidences for further animal experiments and clinical trials on prevention and treatment of restenosis by intracoronary low-intensity laser irradiation at a wavelength of 532 nm.
    Laser Physics 01/2011; 21(11):1989-1994. · 2.55 Impact Factor
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    ABSTRACT: The aim of this article was to study the injury effect of either convergent or parallel argon laser beam on rabbit retina, get the dose-effect relationship for the two types of laser beams, and calculate the damage threshold of argon laser for human retinas. An argon laser therapeutic instrument for ophthalmology was used in this study. A total of 80 rabbit eyes were irradiated for 600 lesions, half of which were treated by convergent laser and the other half were done with parallel laser beam. After irradiation, slit lamp microscope and fundus photography were used to observe the lesions, change and the incidence of injury was processed statistically to get the damage threshold of rabbit retina. Based on results from the experiments on animals and the data from clinical cases of laser treatment, the photocoagulation damage thresholds of human retinas for convergent and parallel argon laser were calculated to be 0.464 and 0.285 mJ respectively. These data provided biological reference for safely operation when employing laser photocoagulation in clinical practice and other fields.
    Laser Physics 01/2011; 21(3):554-558. · 2.55 Impact Factor
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    ABSTRACT: The aim of this paper is to study the effect of low-level laser irradiation (LLLI) on proliferation of myoblasts in culture. Myoblasts derived from rat skeletal muscle were irradiated by He-Ne laser with different doses. Compared with nonirradiated control group, the number of myoblasts increased when the cells in normal culture conditions were exposed to the laser of specific energy density. The amount of cells with proliferating cell nuclear antigen (PCNA) positive expression and the 5-bromo-2′-deoxyuridine (BrdU) incorporation rate after laser irradiation were also higher than that of the control group, suggesting that LLLL at certain doses can effectively enhance myoblasts growth activity in vitro. This study firstly demonstrated that stimulating myoblasts to enter into proliferative stage from initial resting state was an important mechanism of regeneration and repair of injured skeletal muscle promoted by LLLI in clinical treatment.
    Laser Physics 01/2011; 21(12):2122-2127. · 2.55 Impact Factor
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    ABSTRACT: To study 1.06mum laser causing pain in human skin. The skin of human dorsum hand was irradiated by a Nd: YAG laser. The energy of each pulse and whether the subjects felt a painful sensation after each stimulus were recorded. The pain threshold was defined as the laser dose at which the subjects reported a painful sensation to 50% of stimulus deliveries. The pain thresholds were determined under 3 different beam diameter and pulse duration conditions. The influence of skin temperature on the pain caused by laser stimulus was also explored. As the temperature of skin was about 30°C, the pain thresholds were 394mJ/mm2, 36.4mJ/mm2 and 8.92mJ/mm2 respectively under the stimulating condition of 1.20mm beam diameter and 85mus pulse duration, 1.20mm beam diameter and 20ns pulse duration and 2.56mm beam diameter and 20ns pulse duration. Under the first condition, when skin temperature was 25°C and radiant exposure was 383mJ/mm2, the probability of laser stimulus causing pain was 16.7%; when skin temperature was 39°C and radiant exposure was 361mJ/mm2, the probability was 56.7%. The threshold of 1.06mum laser stimulus causing pain decreases with decreasing pulse duration, increasing beam diameter and skin temperature.
    Proc SPIE 11/2010;
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    ABSTRACT: Laser photocoagulation treatment is often complicated by a side effect of visual impairment, which is caused by the unavoidable laser-induced retinal destruction. At present no specific is found to cure this retinopathy. The aim of this study was to observe the neuroprotective effect of bFGF on laserinduced retinal injury. Chinchilla rabbits were divided into three groups and argon laser lesions were created in the retinas. Then bFGF or dexamethasone, a widely used ophthalmic preparation, or saline was given severally by retrobulbar injection. The retinal lesions were evaluated histologically and morphometrically, and visual function was examined by ERG. The results showed that bFGF administration better preserved morphology of retinal photoreceptors and significantly diminished the area of the lesions. Furthermore, bFGF promoted the restoration of the ERG b-wave amplitude. In rabbits treated with dexamethasone, however, the lesions showed almost no ameliorative changes. This is the first study to investigate the potential role of bFGF as a remedial agent in laser photocoagulation treatment. These findings suggest that bFGF has significant neuroprotective properties in the retina and this type of neuroprotection may be of clinical significance in reducing iatrogenic laser-induced retinal injuries in humans. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 10/2010; 7(12):899 - 904. · 7.71 Impact Factor