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51.
Proietti R Lombardi L Quaglia C Sagone A 《Indian pacing and electrophysiology journal》2011,11(5):145-148
There is a general consensus that once a part of an implanted cardiac device becomes infected, it is usually impossible to cure the infection without completely removing all prosthetic material from the body. Consequently the Heart Rhythm Society (HRS) included the pocket infection or erosion as a class I indication for pacemaker lead exctraction. However, the procedure still carries a high risk of life-threatening complications due to fibrotic attachments between leads, veins, valves or other endocardial structures, notwithstanding specific tools and techniques that have been developed to assist the lead removal, preventing tissue laceration. 相似文献
52.
本试验研究了鳞毛蕨科两种植物革叶耳蕨(Polystichum neolobatum)和黑足鳞毛蕨(Dryopteris fuscipes)在不同浓度Cd-Pb复合胁迫下保护酶活性的变化。结果表明,革叶耳蕨POD、SOD、CAT活性与处理浓度呈正相关趋势,即随着处理浓度升高,酶活性明显升高;黑足鳞毛蕨POD、SOD及CAT活性表现出在高浓度(600+1200 mg/kg)处理下受抑制,而在低、中浓度(200+400 mg/kg、400+800 mg/kg)处理下表现为促进作用。 相似文献
53.
54.
The effects of environmental lead on the immune system of young children were assessed by determining the peripheral blood
lymphocytes CD3+, CD4+, CD8+, B(CD19+) counts, and natural killer (CD16+ CD56+) cells in 35 preschool children whose mean blood lead level was 140.6 μg/L. The results were compared to an age- and sex-matched
control group with a mean blood lead level of 64.3 μg/L. Compared to the controls, a significant reduction in the percentage
of CD4+ cells and a significant increase of CD8+ cells were seen in the high-lead group. The negative correlation between the percentage of CD4+ cells and blood lead levels was found to be significant (p<0.01). These results suggest that exposure to environmental lead might result in alterations in the immune function of young
children. 相似文献
55.
González-Reimers E Arnay-de-la-Rosa M Velasco-Vázquez J Galindo-Martín L Santolaria-Fernández F 《Biological trace element research》2005,105(1-3):37-51
This study was performed to determine the levels of lead (Pb) and cadmium (Cd) in 63 bone samples of the prehispanic population
of the island El Hierro, comparing them with the values obtained on 98 prehispanic samples from Tenerife, Fuerteventura, Gran
Canaria, and La Palma, all of them in the Canary Islands, and with eight modern samples who served as controls. Prehispanic
individuals from El Hierro showed the lowest bone Pb values of all the archipelago (0.72±1.01 mg/kg), significantly different
(F=6.9, p<0.001) from the values obtained for the population of other islands such as Tenerife (4.87±5.36 mg/kg) or Fuerteventura (4.45±7.85
mg/kg) and also from those of the modern population (30.53±14.62 mg/kg). On the other hand, bone Cd, although slightly lower
in the ancient population groups, was not significantly different when compared with the modern one. In addition, no differences
were observed in bone Cd among the ancient population of the different islands. Bone lead—but not cadmium—kept an inverse
significant relationship with the distance of the burial site both to south Spain (r=−0.31) and Atlantic Morocco (r=−0.28, p<0.001 in both cases). 相似文献
56.
Two novel metal-organic hybrid coordination polymers {[Cu(bpo)(chdc)(H2O)](H2O)0.5}n (1) and [Pb(chdc)(H2O)]n (2) have been synthesized under different conditions and structurally characterized by single-crystal X-ray diffraction technique, where H2chdc refers to a flexible 1,4-cyclohexanedicarboxylic acid ligand and bpo is 2,5-bis(4-pyridyl)-1,3,4-oxadiazole. Complex 1 has a two-dimensional (2-D) grid-like [11.28 × 13.63 Å2] framework in which the CuII centers are extended via bidentate bridging ligands bpo and e,e-trans-chdc along two directions, exhibiting large porous cavities. Coordination polymer 2 represents the first PbII complex of H2chdc in which the larger PbII centers are connected by e,a-cis-chdc anions to afford a 2-D close-knit structure. 相似文献
57.
This study addresses the impact of small-scale gold mining on the environment and communities of the Puyango River basin in
the southwest of Ecuador between 1999 and 2001. Our primary objectives were to measure mercury, manganese, and lead in the
river, to identify pathways of population exposure, and biological indicators of human exposure. A multi-method design at
the catchment scale was applied to the analysis of water, sediments, and particulate matter for mercury, lead, and manganese
over two different seasons. A household survey was undertaken, and individuals were assessed for lead (blood samples), and
for mercury (urine and hair samples). River water samples had high concentrations of particulate matter (700 mg/L). Mercury
and lead levels in water at the gold processing plants were very high in both seasons (250 ng Hg/L and 160 μg Pb/L). Mercury
and lead, there was a downstream gradient with the areas adjacent to the gold processing plants having the highest levels.
In Portovelo, the Upper Basin city, 14% of the population reported occupational exposure to inorganic mercury. Although no
one in Portovelo consumes water from the river, 10% of the population consume local fish. This contrasts the Lower Basin where
98% of the population consume fish, and 100% use river water for drinking and cooking. Lead blood levels over 20 μg/dl were
found in 39.4% of the study population and blood mercury over 10 μg/L only in 10.0%. Urinary mercury over 4 μg/L was found
in 66.5% of the examined persons. Hair methylmercury did not exceed the safe limit of 2 μg/g, the mean concentration was 1.2 μg/g.
Mining activity and erosion contributes to heavy-metal contamination (mercury, lead, and manganese) throughout the Puyango
Basin. The relation between environmental contamination is complex and further research is being conducted to understand these
relations. 相似文献
58.
Precise blood lead analysis using a combined internal standard and standard addition approach with disposable screen-printed electrodes 总被引:1,自引:0,他引:1
We report here a highly accurate and efficient method for blood lead analysis (BLA) through the use of a disposable electrode. A new type of mercury-plated preanodized screen-printed carbon electrode, together with a thallium(III) internal standard, simplifies calibration and gives easily quantifiable signals for accurate BLA. A preanodization procedure improves the preconcentration ability of the working electrode through the effect of lead (Pb) complexing with an electrogenerated surface functional group, mainly >C=O. Under optimized conditions, the ratio of the anodic stripping peak currents of Pb and Tl (i.e., i(Pb)/i(Tl)) is linear against [Pb] in the window of 1-300 ppb with a correlation coefficient and detection limit (signal-to-noise ratio=3) of 0.999 and 0.23 ppb, respectively. This approach was used to analyze blood samples (n=55) from workers at a local battery factory. The results are consistent with those obtained from graphite furnace atomic absorption spectroscopy and confirm the applicability of the proposed method. 相似文献
59.
重金属铅对鲫鱼乳酸脱氢酶和过氧化氢酶活性的影响 总被引:16,自引:0,他引:16
在实验室条件下,采用毒性实验方法研究不同浓度重金属铅(Pb2 )对鲫鱼血清乳酸脱氢酶(LDH)和血液过氧化氢酶(CAT)活性的影响.研究结果表明,随着金属离子铅浓度的增高血清中乳酸脱氢酶和过氧化氢酶活性下降,但两种酶对铅离子影响的敏感程度不同.影响LDH活性的最低铅离子浓度为0.1mmol/L,而CAT为0.5mmol/L,当Pb2 浓度为1mmol/L时,LDH活性降至10%左右,而CAT仅下降50%左右.对重金属离子浓度与酶活性的定性和定量分析为有效监控鱼类生存环境提供了有价值的参考资料. 相似文献
60.
铅污染现状及其修复机理研究进展 总被引:5,自引:0,他引:5
介绍了铅污染的现状、修复机理及存在的问题。其中重点阐述了国内在寻找铅的超累积植物的研究进展,国外研究者对铅在植物体内吸收、运输和储存机理方面的研究现状,同时对已发现的与铅污染有关的基因以及转基因技术的应用情况进行了简单介绍,并探讨了提高铅污染修复效率的一些方法。 相似文献