丘脑中央下核在痛觉感受与痛觉调制中的作用

本结合笔的工作,综述了近年来关于丘脑中央下核（Ｓｍ）在痛觉感受与痛觉调制中作用的研究。结果表明,它可能主要与痛觉的情绪激动成分有关,而且Ｓｍ－ＶＬＯ－ＰＡＧ可能构成一个痛觉调制的通路,通过脑干下行抑制系统在脊髓水平调制伤害感受性输入,从而产生痛觉的负反馈性调节。     

激光参数对果胶酶产生菌变株产酶特性的影响

采用Ｋｒ＾＋、Ａｒ＾＋、Ｈｅ－Ｎｅ、ＬＤ、ＹＡＧ倍频等多种激光辐照果胶酶产生菌－黑曲霉。在同一波长、同一照射剂量下,不同辐照功率与时间的组合将产生变株产酶特性的不同变化,实验中存在着一个最佳辐照时间与功率的组合。在同一照射剂量、同一辐照功率与时间组合的条件下,变株果胶酶活变异率随波长变化基本呈线性关系。紫外光、可见光产生的酶活正变率与最大增幅高于红外光。激光的连续或不同调制频率的输出方式可能影响黑     

非热微波和方位对水迷宫大鼠空间认知的影响

描述了四组大鼠六个训练期从上释放点寻找圆形水迷宫（Ｍｏｒｒｉｓ）固定没水平台的动物行为实验,四组动物为,脉冲微波组（２４５０,ＭＨＺ,调制脉宽２μｓ,每秒５００脉冲,空间平均功率密度为２ｍＷ／ｃｍ＾２,平均整体特异吸收率ＳＡＲ,１．２ｗ／ｋｇ）,连续微波组（２４５０ＭＨＺ,无调制。空间平均功率宴席和ＳＡＲ同于脉冲微波组）,Ｓｈａｍ辐射组以及笼养对照组。以平均逃逸时间和速度为测量,考查它们的空间记忆     

510.6nm激光照射对兔血管平滑肌细胞增殖的影响

本文用５１０．６ｎｍ 波长激光以功率密度１、５、１０ ｍ Ｗ／ｃｍ ２ 和能量密度２、４、６Ｊ／ｃｍ ２ 照射体外培养的兔血管平滑肌细胞（ＳＭＣ）,通过３Ｈ－ ＴｄＲ掺入率和细胞生长曲线测定细胞增殖率。结果显示,上述激光照射量均能抑制细胞增殖率,其中以１０ｍ Ｗ／ｃｍ ２ 组的作用最为显著     

不同剂量的He—Ne激光对Raji细胞膜表面SH的影响

本文以离体培养的Ｒａｊｉ细胞为材料,采用ＥＬＬＭＡＮ方法检测了不同剂量的Ｈｅ－Ｎｅ激光对Ｒａｊｉ细胞膜表面ＳＨ含量的影响。发现０．５Ｊ／ｃｍ＾２Ｈｅ－Ｎｅ激光能量可明显增加膜表面ＳＨ含量（Ｐ〈０．０５）。大于或小于此剂量的Ｈｅ－Ｎｅ激光对膜表面ＳＨ含量的影响均不明显（Ｐ〉０．０５）。提示０．５Ｊ／ｃｍ＾２的激光能量对膜有刺激作用。     

低能量氦氖激光照射对荷瘤小鼠T淋巴细胞增殖反应的影响

目的：本文研究低能量氦氖激光照射荷瘤小鼠,观察对荷瘤Ｔ淋巴细胞增殖反应的影响。结果：ＢＡＬＢ／Ｃ雄性小鼠腹腔接种Ｓ１８０接种后,进行激光照射小鼠内眼角,测定正常对照组、肿瘤对照组和７．３３、１１．００、１４．６７、２２．００Ｊ／ｃｍ＾２和２９．３３Ｊ／ｃｍ＾２五个剂量激光照射组小鼠的Ｔ淋巴细胞增殖反应,结果表明１１．００Ｊ／ｃｍ＾２、１４．６７Ｊ／ｃｍ＾２、２２．００Ｊ／ｃｍ＾２剂量的氦氖激光照射     

石斛离体培养中ABA对诱导花芽形成的影响

由兰科植物铁皮石斛（Ｄｅｎｄｒｏｂｉｕｍ ｃａｎｄｉｄｕｍ Ｗａｌｌ．ｅｘ Ｌｉｎｄｌ．）种子诱导形成的愈伤组织,在光照下置于ＭＳ附加０．３ ｍ ｇ／ＬＮＡＡ 的培养基上繁殖,可以形成原球茎。将原球茎转入ＭＳ含２ ｍ ｇ／Ｌ ６－ＢＡ 和０．５ ｍ ｇ／ＬＮＡＡ 的培养基上,花芽形成频率为２７．０％ 。原球茎先在０．５ ｍ ｇ／ＬＡＢＡ的培养基上预培养１５ ｄ,再转入含２ ｍ ｇ／Ｌ６－ＢＡ 的ＭＳ培养基上培养,花芽形成频率明显提高,可达８４．４％ ,而且每株植株花的数目增加;但是在仅有ＡＢＡ 的ＭＳ培养基上培养的原球茎再生的植株未见花芽形成     

猫外膝体神经元时间频率调谐特性的研究

用示波器产生亮度受正弦波调制的小光点刺激清醒猫外膝体神经元的感受野,以不同调制频率下神经元放电的平均频率为指标,分析了126个细胞感受野中心的时间频率调谐特性,主要结果如下。(1)大多数(93.7%)细胞呈调制-兴奋型反应,即刺激光的时间调制在一定频率范围内使放电频率增加;少数(6.3%)细胞呈调制-抑制型反应,即在一定频率范围内,时间调制使放电减少。(2)根据调谐曲线的形状和通带宽度,调制-兴奋型反应包括带通滤波器和低通滤波器两种类型,其110个调谐曲线的峰值分布接近正态曲线,多数细胞对7Hz 的调谐最敏感。调制一抑制型反应包括带除滤波器和低除滤波器两类。(3)调制-兴奋型曲线的通带旁边较當出现抑制性侧带,调制-抑制型曲线出现兴奋性侧带。(4)感受野中心区与外周区的时间频率调谐曲线的带宽和形状有所不同。     

舟山某码头近地面大气微生物污染初步调查

本文报告了用ＦＡ－Ⅰ空气微生物采样器测定了舟山某码头近地面大气细菌和真菌的浓度分布、粒子大小以及对细菌染色形态观察。结果表明,大气中的细菌浓度为１１３ＣＦＵ／ｍ３,真菌为２６５ＣＦＵ／ｍ３。细菌的ＣＭＤ为４．９０ｕｍ,ＧＳＤ为２．７５,真菌的ＣＭＤ为４．８０ｕｍ,ＧＳＤ为１．５０。细菌染色镜检观察,革兰氏阳性菌占８８．９％,阴性菌占１１．１％。阳性菌中球菌最多,无芽胞杆菌次之,芽胞杆菌最少。阴性菌中无芽胞杆菌最多。     

秸秆覆盖免耕对土壤细菌群落区系的影响

多年连续秸秆覆盖免耕对土壤细菌群落影响很大,免耕可提高０－１０ｃｍ土层土壤细菌总数、放线菌数、棒状细菌数和贫营养细菌数量,特别是免耕土壤能使芽孢杆菌数量增多几倍。     

Molecular level damages of low power pulsed laser radiation in a marine bacterium Pseudoalteromonas carrageenovora

AIM: To study the molecular level damages in a marine bacterium, Pseudoalteromonas carrageenovora, exposed to low power pulsed laser radiation from an Nd:YAG laser. METHODS AND RESULTS: The laser damages in bacterial DNA were monitored by studying the formation of apurinic/apyrimidinic (AP) sites. Molecular probe kits were used for this purpose. Occurrence of lesions in the cell walls was monitored under a transmission electron microscope (TEM). The results showed that laser radiation significantly increased the number of AP sites in the bacterial DNA. This increase corresponded to the laser fluence (J cm(-2)) and to the duration of laser irradiation. TEM observation showed the occurrence of lesions in bacterial cell walls upon laser irradiation. CONCLUSIONS: It is concluded that bacteria exposed to laser irradiation suffers DNA damages and resulted in broken cell walls. These events led to bacterial mortality. These are in addition to the mechanisms reported earlier such as the photochemical reactions occurring inside the cells upon exposure to low power laser. SIGNIFICANCE AND IMPACT OF THE STUDY: These results help us to understand the mechanisms of bacterial mortality on exposure to low power pulsed laser irradiation and are useful in formulating a laser treatment strategy to kill bacteria.     

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.     

Laser impact assessment in a biofilm-forming bacterium Pseudoalteromonas carrageenovora using a flow cytometric system

Impact by pulsed laser irradiations from an Nd:YAG laser on the marine biofilm-forming bacterium Pseudoalteromonas carrageenovora has been studied using a flow cytometric system. The biofilm-forming bacteria in the planktonic state have been irradiated while flowing, and the mortality and bacterial attachment have been determined by exposing TiN coupons in the system. Coupons suspended in the non-irradiated bacterial flow were treated as the control. The fluence used in the study was 0.1 J/cm(2). Three flow rates (14, 28, and 42 cm/min) and two exposure durations (15 and 30 min) were tested. The results showed the increase in bacterial mortality with the decrease in flow rate. The maximum mortality of 27.5% was observed when the flow rate was 14 cm/min. The bacterial attachment increased with the increase in flow rate and exposure duration. The area of bacterial attachment on the experimental coupons exposed to the irradiated sample was significantly lesser than that for the nonirradiated sample. The results thus show in a flowing system, low power pulsed laser irradiations could reduce the bacterial attachment even though it did not cause significant mortality.     

Insertion of microscopic objects through plant cell walls using laser microsurgery

A detailed protocol is presented for precisely inserting microscopic objects into the periplasmic region of plant callus cells using laser microsurgery. Ginkgo biloba and Agrobacterium rhizogenes were used as the model system for developing the optical tweezers and scalpel techniques using a single laser. We achieved better than 95% survival after plasmolyzing G. biloba cells, ablating a 2-4-μm hole through the cell wall using a pulsed UV laser beam, trapping and translating bacteria into the periplasmic region using a pulsed infrared laser beam, and then deplasmolyzing the cells. Insertion of bacteria is also described. A thermal model for temperature changes of trapped bacteria is included. Comparisons with other methods, such as a reverse-pressure gradient technique, are discussed and additional experiments on plants using laser microsurgery are suggested. Copyright 1998 John Wiley & Sons, Inc.     

A study of the functional activity of macrophages of peritoneal exudate of mice exposed to low-intensity laser radiation in vitro and in vivo

The effect of low-intensity laser radiation generated by semiconductor devices in the red (650 nm) and infrared (850 nm) regions of the spectrum in vitro and in vivo on the phagocytic activity and synthesis of proinflammatory cytokines by peritoneal macrophages during the phagocytosis of bacterial cells has been studied. A culture of the clinical strain of the enteropathogenic bacterium Escherichia coli was used as an object. The radiation dose was varied by changing the power and duration of exposure. The results obtained indicate that infrared low-intensity laser radiation has a stimulating effect on the phagocytic activity of macrophages. It was shown that the effect of low-intensity laser radiation on the activity of the phagocytic process, the enhancement of the adhesion of bacteria by macrophages, killing of bacteria, and the production of proinflammatory cytokines is dose-dependent. The exposure to the rays of the red region of the spectrum on phagocytizing macrophages induced a decrease in their activity; as the dose was increased, the destruction of cells was registered.     

Bactericidal action of carbon dioxide laser radiation in experimental dental root canals

The ability of a carbon dioxide laser to sterilize the root canal of human teeth has been investigated. Three oral bacteria, Streptococcus sanguis, Streptococcus mutans, and Actinomyces viscosus, and three other bacteria, Bacillus cereus, Staphylococcus aureus, and Pseudomonas aeruginosa were used as experimental organisms. Exposure of cells on glass slides to laser radiation showed there was little difference in the exposure required to kill these six organisms. Complete recovery of bacteria from the root canal was initially a problem and was only achieved when bacterial manipulations and removal were carried out in rapid succession, within 5 min of inoculation. However, the geometry of the instrumented canal and the laser alignment were major factors in achieving consistent cell death of oral bacteria in the root canals. Using sets of 10 teeth, four repeated exposures of 10 W for 1 s was found to sterilize 4 or more of the teeth.     

MALDI-TOF质谱技术分析与鉴定病原细菌研究

本文通过基于基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)技术分析病原细菌的方法进行研究, 阐明影响分析结果的重要因素, 并建立了MALDI-TOF-MS 分析病原细菌的标准方法。对不同属、种和亚种的12株植物病原细菌进行全细胞分析结果表明：MALDI-TOF-MS能快速而准确的区分和鉴定病原细菌, 分析过程简单、灵敏度高。此法在细菌属、种、亚种和菌株水平上, 可快速、准确地区分和鉴定。     

Visible laser and UV-A radiation impact on a PNP degrading Moraxella strain and its rpoS mutant

The role of stationary phase sigma factor gene (rpoS) in the stress response of Moraxella strain when exposed to radiation was determined by comparing the stress responses of the wild-type (WT) and its rpoS knockout (KO) mutant. The rpoS was turned on by starving the WT cultures for 24 h in minimal salt medium. Under non-starved condition, both WT and KO planktonic Moraxella cells showed an increase in mortality with the increase in duration of irradiation. In the planktonic non-starved Moraxella, for the power intensity tested, UV radiation caused a substantially higher mortality rate than did by the visible laser light (the mortality rate observed for 15-min laser radiation was 53.4 +/- 10.5 and 48.7 +/- 8.9 for WT and KO, respectively, and 97.6 +/- 0 and 98.5 +/- 0 for 25 s of UV irradiation in WT and KO, respectively). However, the mortality rate decreased significantly in the starved WT when exposed to these two radiations. In comparison, rpoS protected the WT against the visible laser light more effectively than it did for the UV radiation. The WT and KO strains of Moraxella formed distinctly different types of biofilms on stainless steel coupons. The KO strain formed a denser biofilm than did the WT. Visible laser light removed biofilms from the surfaces more effectively than did the UV. This was true when comparing the mortality of bacteria in the biofilms as well. The inability of UV radiation to penetrate biofilms due to greater rates of surface absorption is considered to be the major reason for the weaker removal of biofilms in comparison to that of the visible laser light. This result suggests that high power visible laser light might be an effective tool for the removal of biofilms.     

Effect of He-Ne laser radiation on the bacteriophage T4-Escherichia coli system

Exposure of T4 bacteriophage, having no red light chromophores, to He-Ne laser (lambda = 632.8 nm) of 10(3)-6 X 10(4) J/m2 does not influence its lytic properties. Irradiation of E. coli WP2 bacteria with doses of 4-6 X 10(3) J/m2 causes a 1.25-1.35-fold increase in their ability to keep on the development of nonirradiated bacteriophage T4.     

Inhibition of bacterial attachment by pulsed Nd:YAG laser irradiations: an in vitro study using marine biofilm-forming bacterium Pseudoalteromonas carrageenovora

The effect of low mean power laser irradiations with short pulse duration from an Nd:YAG (neodymium-doped yttrium aluminium garnet) laser on a marine biofilm-forming bacterium, Pseudoalteromonas carrageenovora, was investigated in the laboratory. Laser-irradiated bacteria were tested for their ability to attach on nontoxic titanium nitride (TiN) coupons with nonirradiated bacteria as the reference. Two durations of irradiation were tested, 10 and 15 min. Bacterial attachment was monitored after 20 min, 40 min, and 1 h of irradiation. The average laser fluence used for this study was 0.1 J/cm(2). The area of attachment of the irradiated bacteria was significantly less than the reference for both durations of irradiation. The growth of irradiated bacteria showed a longer lag phase than the nonirradiated sample, mainly due to mortality in the former. The bacterial mortality observed was 23.4 +/- 0.71 and 48.6 +/- 6.5% for 10- and 15-min irradiations, respectively. Thus, the results show that low-power pulsed laser irradiations resulted in a significant bacterial mortality and a reduced bacterial attachment on nontoxic hard surfaces.