石墨炉原子吸收法测定全血中铅的探讨

铅(Pb)，是多系统、多亲和性的重金属毒物，主要是嗜胎盘和嗜神经性毒物，铅在体内任何痕量的存在即会造成伤害，如达到一定浓度，还会对儿童大脑造成不可逆转的损害。血铅值反映近期铅的摄入量，常作为体内暴露水平的重要指标。世界卫生组织(WHO)规定了各类人群的血铅生物阈限值，儿童为100ug／L。目前国家未见推荐方法，1999年，卫生部颁布了标准编号为WS／T174—1999血铅的酸脱蛋白——石墨炉原子吸收光谱法，我们参照此方法并改用10％     

对进口咖啡豆中铅测定质量控制初探

本文通过对进口咖啡豆中铅的测定,初步进行实验室内质量控制分析———即在一个周期内(30天)连续对进口咖啡豆中的铅元素含量进行测定,系统地对分析方法、仪器设备、试剂、操作者等因素进行研究,其方法的检出限为0.27μg/mL,回收率为111%~117%。通过绘制进口咖啡豆中铅的质量控制图,其结果是在授控范围内。     

动车组齿轮箱润滑油更换周期优化

目前齿轮箱润滑油更换是按照供应商提供的换油周期执行，缺乏对实际运用条件下齿轮箱润滑油性能状态变化情况的跟踪和研究分析。为准确确定CRH380B平台动车组齿轮箱润滑油合理的换油周期，通过理化性能分析以及污染物含量和磨损元素含量变化趋势分析，开展齿轮箱润滑油关键指标变化趋势研究；建立关键指标随油品运行里程变化的数学模型，并对油品运行里程进行预测。结果表明：CRH380B平台动车组齿轮箱润滑油更换周期延长至60万km可行；Fe元素含量变化可作为齿轮箱润滑油重点监控的指标；通过Fe元素含量随油品运行里程变化的数学模型，预测CRH380B齿轮箱润滑油在运行至80万km后仍满足使用要求。     

钨舟铅镉元素分析仪与石墨炉原子吸收分光光度计测定血铅方法的比较

通过对钨舟铅镉元素分析仪与石墨炉原子吸收分光光度计测定血铅方法的比较,为检测机构选择检测方法提供参考依据。应用两种方法分别对血铅测定进行方法的精密度、检出限、定量下限试验,对76件人血样品进行测定,测定结果进行相关性分析。两种方法测定血铅均有较高的灵敏度、较好的准确性及精密度。两种方法的相对标准偏差（RSD）均小于7%;钨舟原子吸收光谱法的检出限（3×SD）为0.6μg/L,定量限（10×SD）为1.9μg/L;石墨炉原子吸收光谱法的检出限（3×SD）为0.5μg/L,定量限（10×SD）为1.6μg/L。对4种不同浓度水平的标准物质：美国NIST标准物质山羊血955C（955C2、955C3、955C4）和国家标准物质牛血铅（GBW09154）测定,测定值均在标准值范围内,两种方法对76件人血样品血铅检测的结果经t检验无显著性差异。两种测定血铅的方法均符合方法学要求,检验结果呈高度相关,均适用于血铅的测定。     

重金属铅在油菜中的盆栽实验研究

设计盆栽实验,研究在同样的生长条件下,分别施加不同含量(低浓度、中等浓度和高浓度)的Pb后,选取不同的生长周期,对比高生物量作物油菜的生长繁殖能力以及在植物体内的Pb含量的变化。通过改变土壤p H值,利用原子吸收法测定植物体内不同部位的重金属Pb的含量,进行检测和分析,绘制图表并加以说明,得出相应结论。     

高效液相色谱-串联质谱法测定大鼠组织中的吡蚜酮

为研究不同染毒剂量下吡蚜酮原药在大鼠体内的毒代动力学特征,以SD大鼠为研究对象,经口灌胃方式单次染毒,采集不同时间点的动物组织样品,经蛋白沉淀处理后,以吡虫啉为内标,采用高效液相色谱-串联质谱法（HPLC-MS/MS）检测大鼠组织中的吡蚜酮原型。结果表明,吡蚜酮在50~10 000 μg/L浓度范围内,线性关系良好,相关系数大于0.98,批内精密度相对标准偏差小于15%。经口染毒后,吡蚜酮在大鼠体内分布较广,给药10 min后,在主要脏器中均检测到吡蚜酮原型,2 h后在多数组织中吡蚜酮浓度达最高峰,而至144 h,除肝脏外,其他组织中吡蚜酮浓度均降至最低定量限以下。此结果与血浆动力学结果吻合,表明该药物在大鼠体内不会长时间蓄积,安全性较高。     

骨髓间充质干细胞对糖尿病视网膜病变大鼠血糖及视网膜功能影响

目的 :探讨尾静脉注射骨髓间充质干细胞对糖尿病视网膜病变大鼠血糖及视网膜功能的影响。方法 :48只健康大鼠随机选取10只为正常对照组,38只建立糖尿病视网膜病变大鼠模型后,20只采用尾静脉注射间充质干细胞,18只注射等量安慰剂。观察间充质干细胞在肝、脾、肾、胰腺和眼球的分布以及在视网膜的分化特点,监测注射后1、2、3、4wk血糖变化,观察血-视网膜屏障破坏修复情况。结果 :BMSCS在肝、脾、肾、胰腺、肺等组织中均有分布,视网膜外核层可见到大量密集的BMSCs重叠存在。实验组大鼠的血糖水平均随干预时间延长逐渐下降,注射后第1 wk血糖差异即有统计学意义。EB渗漏量较基线明显减少。结论 :BMSCs可降低糖尿病视网膜病变大鼠血糖,使血-视网膜屏障得到一定程度修复。     

水质铅自动在线监测仪测定水样中铅的含量

首先,构建了基于聚苯乙烯-双硫腙纳米纤维的铅离子富集前处理装置,可以有效地降低铅的检出限并提高检测灵敏度和选择性。其次,研发了水质铅自动在线分析监测仪,以预镀汞膜的玻碳电极为工作电极,采用阳极溶出伏安法,对实验参数进行了优化,例如预镀汞膜的条件、缓冲液的种类和浓度、铅富集时间和电压等。在最优化条件下,铅的溶出峰面积与其浓度在0～2000μg/L 范围内呈现良好的线性关系,其回归方程为 y1＝-0.07843＋0.00269 x （相关系数为0.998,浓度范围为5～2000μg/L ）,y2＝-0.0035＋0.00178 x （相关系数为0.998,浓度范围为5～100μg/L ）,检出限为0.38μg/L。在此基础上,采用标准加入法对水样中铅的含量进行了测定,并与原子吸收法的测定结果进行了比较。结果显示,该水质铅自动在线监测仪具有快速、准确、简便、灵敏等优点。     

镁离子对金雀异黄素在遗传性高血压大鼠血压调节作用的影响

目的观察镁离子和金雀异黄素单独以及联合作用下对自发性高血压大鼠血压的影响。方法 7只Wistar Kyoto(WKY)大鼠作为WKY对照组,28只成年雄性自发性高血压大鼠(SHR)随机分为SHR对照组、镁离子组(M组)、金雀异黄素组(G组)、镁离子+金雀异黄素组(GM组),n=7,每日同一时间分别给予下述条件干预:SHR对照组及WKY对照组给予鼠尾静脉注射氯化钠溶液,镁离子组给予鼠尾静脉注射0.075mol/L氯化镁溶液,金雀异黄素组给予鼠尾静脉注射金雀异黄素溶液5mg/Kg,镁离子+金雀异黄素组给予鼠尾静脉注射金雀异黄素+MgCl_2溶液,各组大鼠给药两小时后采用无创鼠尾动脉血压测量分析系统测量血压。结果 SHR对照组大鼠的收缩压升高幅度比其他四组的收缩压升高幅度大(p0.05),且随时间及体重的增长而不断升高,收缩压升高幅度最大。经单因素方差分析,GM组对抗高血压的效果与G组相比在第25天和第30天有明显差异(p0.01),GM组对抗高血压的效果要优于G组。GM组对抗高血压的效果与M组相比从第15天开始有明显差异(P0.01),GM组对抗高血压的效果要优于M组。结论金雀异黄素与镁离子联合使用有效的抑制了高血压的发展,二者在对抗自发性高血压大鼠收缩压方面具有协同作用;镁离子对金雀异黄素在对抗自发性高血压大鼠收缩压方面可能有促进作用。     

血液中铅镉分析方法的研究

在人体中,铅和镉都属于有害元素。随着工业的发展,铅、镉的世界排量及排入环境汇总的量逐年增加,排入环境中的铅和镉通过空气、水、食物、烟草、饮料等途径进入人体,对人体健康构成潜在危害。本文利用石墨炉原子吸收光谱法,采用直接稀释方式处理血液,并用中国疾病预防控制中心的标准样品进行对比。结果表明,利用血液铅镉分析仪作为分析仪器,直接测定血液中铅、镉含量,结果可靠。     

The influence of lead nanoparticles on the morpho‐functional changes of rat liver during the postexposure period

Lead as any heavy metals may be found in soil, water, air, and is used in everyday life. Once in the body, it causes toxic effect, making the liver, which is one of the main organs of detoxification, suffer. Recently, the study of the action of not only ionic forms of lead, but also its nanoparticles, has become topical. The study aims at determining changes in the liver of rats and biochemical changes in their blood both at late term of exposure to nanoparticles of lead compounds and in the post‐exposure period. The study was performed on 120 male rats of Wistar line, which were divided into two series, each series containing four groups. The first and the second groups of animals were intraperitoneally injected with colloidal solution of nanoparticles of lead sulfide of 10 and 30 nm in size, and the third group were intraperitoneally injected with a solution of lead nitrate. The fourth group of animals served as control. In the first series, the investigated substances were administered 60 times within 12 weeks. In the second series, after 60‐fold administration of the investigated substances, the exposure was discontibued and animals were observed for 6 weeks—overall duration of 18 weeks. Histological, morphometrical and biochemical methods were used. The body weight was reduced in the rats exposed to PbS_nano1 at week 12 of experiment and in rats exposed to both PbS_nano1 and Pb(NO₃)₂ in the second series. Absolute liver weight increased at week 12 of experiment in all experimental groups. In the second series this value almost reached that of the control level. Relative liver weight in the animals of all experimental groups was higher than that in the control at week 12 of experiment. In the second series this value remained higher in rats exposed to PbS_nano1. After 12 weeks of exposure dystrophic changes in the liver were found in all experimental groups. At week 6 after the exposure (the second series) destructive changes in the liver decreased. Total protein, albumin, glucose, total lipids, cholesterol, triglycerides content in blood serum corresponded with morphological data. The experiment has demonstrated that the 12 weeks long exposure to lead nanoparticles had harmful effect on the liver. Within the postexposure 6‐weeks period structural changes in the liver and biochemical changes in blood serum decreased. Biochemical changes in blood serum corresponded to the morphological data. By many parameters PbS_nano1 had more pronounced harmful effect. Toxicity of PbS_nano2 and Pb(NO₃)₂ were comparable.     

组大鼠毛细血管内的镧盐颗粒穿过血脑屏障进入到脑组

生长发育期铅接触可使血脑屏障通透性增加,脑毛细血管内皮细胞紧密连接蛋白occludin表达降低可能是血脑屏障通透性改变的主要分子机制之一;铅接触的同时适量补充铁元素,可保护由慢性铅接触所造成的血脑屏障紧密连接的损伤.Effects of iron suppleme     

Effect of 45S5 bioactive glass on the microshear bond strength of dental fluorosis

The aim of this in vitro study was to estimate the effect of the species concentration of 45S5 bioactive glass (BAG) used as pretreatment on the microshear bond strength (MSBS) of dental fluorosis (DF). Based on the Thylstrup and Fejerskov index, 80 teeth were randomly divided equally into four groups: TFI 0, sound dentin; TFI 1–3, mild fluorosis; TFI 4–5, moderate fluorosis; and TFI 6–9, severe fluorosis. Each group was randomized into five subgroups. After preparing the dentin hypersensitivity model of DF, the dentin was pretreated as follows, Subgroup 1: deionized water (Control group); Subgroup 2: 1% BAG; Subgroup 3: 5% BAG; Subgroup 4: 10% BAG, and Subgroup 5: 20% BAG. Stochastically one specimen was selected from each subgroup for scanning electron microscope and energy dispersive spectrometer analysis. After being made of resin–tooth bonding samples, the remains were in water bath at 37 °C for 24 hr. Subsequently, samples from each subgroup were randomly selected to test MSBS without aging, or after a thermocycle of 5,000 and 10,000 times, respectively. The fracture modes were analyzed. Compared with the group of 1% BAG and Control, the exposure area of tubules in 5%, 10%, and 20% BAG group had significant difference (p < .05). MSBS results indicated that there were significant differences between 10% BAG with other groups. The 20% BAG group showed the lowest MSBS among all groups. Pretreatment of 10% BAG solution may be conductive to enhance the bond strength of DF, while 20% BAG solution adversely.     

烟气暴露对大鼠代谢轮廓谱的影响

运用基于液相色谱-质谱联用技术的代谢组学方法研究了不同卷烟烟气暴露对大鼠内源小分子代谢物组的影响。分别建立了大鼠血清和尿液的代谢轮廓谱,分析了烟气暴露7天、14天和30天时对照组大鼠、普通卷烟暴露组大鼠及含有天然本草添加剂的某品牌卷烟暴露组大鼠的血浆和尿液样本,采用偏最小二乘判别分析（PLS-DA）对数据进行模式识别。结果表明,普通卷烟和天然本草添加卷烟均会影响大鼠整体代谢状态,干扰大鼠磷脂、能量代谢,并对其造成氧化损伤,但天然本草添加卷烟对大鼠的损伤程度低于普通卷烟。在烟气暴露30天时,一些重要标志物在各组相对含量的变化进一步证实了天然本草添加卷烟可降低烟气对大鼠整体代谢的影响,减轻烟气造成的损伤。因此,在烟草中加入天然本草添加剂可在一定程度上减少烟气对机体的伤害,改善体内因烟气干扰而紊乱的磷脂和能量代谢。     

基于质谱技术的黄芩治疗2型糖尿病的粪便代谢组学研究

采用粪便代谢组学方法,运用超高效液相色谱-四极杆飞行时间质谱（UPLC-Q-TOF MS）技术研究了黄芩治疗2型糖尿病大鼠的作用机制。采用主成分分析（PCA）和正交偏最小二乘法判别分析方法 （OPLS-DA）对健康对照组、2型糖尿病模型组和黄芩治疗组的大鼠粪便中内源性代谢物进行分析,寻找黄芩治疗2型糖尿病大鼠的潜在生物标志物。结果表明,健康对照组、2型糖尿病模型组和黄芩治疗组的大鼠粪便代谢图谱有显著的区分;发现并鉴定了11种潜在的生物标志物。黄芩对2型糖尿病大鼠的鞘脂类代谢和脂肪酸代谢具有调节作用;对三羟基三甲基吲哚酮、白三烯E4、亮氨酰脯氨酸和雌二醇的含量具有调节作用;同时,大鼠体重和空腹血糖的变化趋势表明,黄芩具有改善糖尿病症状的作用。     

The effect of different thermal treatment on the physical properties of PGA/PCL copolymer suture material

Samples of polyglycolic acid PGA/polycaprolactone PCL copolymer absorbable suture materials, which is called Poliglecaprone PGC copolymer suture, were thermally treated by two different processes. The first method is the direct heat exposure, from 20 to 38 °C, in the surrounding medium. Which is an environmental study. The other method is the annealing process at temperatures ranged from 65, 80, 100, 120, and 140 °C, for two different duration periods 60 and 120 min. This is an extensive technical study. The refractive indices of thermally treated PGA/PCL copolymer sutures were measured using multiple‐beam Fizeau fringes. The birefringence profiles across the suture cross‐sections were studied for different annealing conditions. The effect of heat on the polarizabilty per unit volume, dielectric properties, and suture diameter were investigated. The activation energy for the heating processes was calculated using Arrhenius equation. Microinterferograms are given for illustration.     

Early changes induced by short-term low-dose cadmium exposure in rat ventral and dorsolateral prostates

Prostate cancer (PCa) is the most commonly diagnosed cancer in men. The etiology of PCa in humans is multifactorial and includes age, ethnicity, environmental factors, and other unknown causes. Epidemiological and experimental evidence has shown that cadmium is associated with PCa both in humans and rodents. This metal can act as an endocrine disruptor during prostate development, and it induces prostate lesions late in life. In this study, we investigated the effects of low-dose cadmium on rat prostate morphology during puberty. Two-month-old male Wistar rats were randomized into two experimental groups: cadmium-treated and control. The ventral and dorsolateral prostates were dissected, weighed, and immunohistochemically stained with specific antibodies against Ki-67 and the androgen receptor (AR). The concentration of cadmium was measured in the blood and prostate, and testosterone concentration was measured from the plasma. Our results show that cadmium concentration was increased in both the blood and the prostate of cadmium-treated rats, but there were no changes in the prostatic weight, epithelial cell height, or testosterone levels. However, AR immunostaining and epithelial cell proliferation (Ki-67 index) were increased in both prostates with an increase in apoptosis only in the dorsal lobe. Furthermore, atypical hyperplasic proliferative lesions were found in the dorsolateral lobe after cadmium exposure. Cadmium treatment reduced collagen fiber absolute volume in both prostates. Thus, low-doses of cadmium, even for a short period of time, can interfere with prostate epithelium-stroma homeostasis, and this disruption might be an important factor in the onset of prostate lesions late in life.     

Tracers in vascular casting resins enhance backscattering brightness

Studying cast microvasculature with scanning electron microscopy has expanded our knowledge of many circulations, but need arises to determine the blood source of vascular beds that are supplied by two circulations. One way to do this is to mark the casting resin by adding a tracer compound that can be detected in the scanning electron microscope. A potential method of distinguishing different substances is to detect the backscattered electrons that are emitted from the tracer if the tracer is a heavier element, because heavier elements backscatter more electrons. To explore different tracers, we tested lead, titanium, iron, osmium, and uranium as solutions of different polarity and powders. The tracers were added to 1 ml of methyl methacrylate in log concentrations. Shrinkage, hardness, cast quality, and change in brightness from the tracer were compared with multivariate analysis at scanning electron microscopic working distances of 15 and 39 mm on carbon-coated and uncoated specimens. Several concentrations caused sedimentation of the tracer and prevented the resin from solidifying. Tetraethyl lead shortened the hardening time: uranyl acetate and osmium tetroxide prolonged it. Most tracers decreased shrinkage. When lead citrate and Reynolds solutions were removed, the brightness correlated with increasing atomic number, concentration of the tracer, and mean atomic number of the specimen (p <0.0001). The substances that increased contrast most were tetraethyl lead and uranium. Backscattering electron detection can distinguish methacrylate casts that have small amounts of heavier elements added to them, but an optimal tracer has not yet been established.     

In vitro assessment of laser efficiency for caries prevention in pits and fissures

This study aimed to assess the in vitro efficacy of the lasers Er:YAG, Nd:YAG, and CO(2) operating in the low energy mode for caries prevention in pits and fissures. Forty-five caries-free enamel occlusal sections were randomly divided into three groups: G1 - Er:YAG (80 mJ/2 Hz); G2 - Nd:YAG Laser (1 W and 10 Hz); and G3 - CO(2) Laser (0.4 W and 20 Hz). After surface treatment, the samples were submitted to challenge with acid consisting of a 10-day immersion in demineralizing (6 h) and remineralizing solution (18 h). Next, enamel demineralization was quantitatively evaluated by subsurface microhardness test and polarized-light microscopy (PLM, mm(2)) and qualitatively assessed by scanning electron microscopy. The Wilcoxon test was used for comparison of each group with its own control. ANOVA (α = 5%) was employed for comparison among groups, and Fisher's LSD multiple comparison test was applied, to check the difference in means. Concerning the microhardness analyses, statistical difference between control, and experimental areas was only detected for the CO(2) group. Experimental values were higher than the controls. As for PLM analyses, smaller demineralized areas were measured for G2 (Nd:YAG) and G3 (CO(2)) compared with the control areas. In conclusion, the present findings suggest that the CO(2) laser should be selected in order to increase the enamel resistance to acid in pits and fissures.