Sodium retention in rats with cadmium-induced hypertension

Chronic feeding of non-toxic doses of cadmium induces an average increase of 15 to 20 mm Hg in indirectly measured systolic pressure of lightly anaesthetized rats. The mechanism of this increase is not known, but cadmium has several potentially pressor effects, including increased sodium retention. This report describes both sodium balance and blood pressure in a pair of experiments where cadmium was fed and in a pair where it was injected. All four cadmium challenges induced sodium retention and also induced hypertension. Thus, rats with either low or moderate chronic exposure to fed cadmium (well below the exposures required to induce toxicity) retained more intraperitoneally injected radiosodium than controls and at the same time developed higher systolic pressures than controls. Immediately following intraperitoneally injected cadmium, rats lost a radiosodium load more slowly than controls or alternately accumulated dietary radiosodium more rapidly than controls; in both situations the blood pressure was higher than in controls. These data indicate that some of the pressor effect associated with cadmium exposure could result from its concomitant antinatriuretic effect.     

右心室经胸穿刺测压法在肺动脉高压大鼠模型中的应用

探讨应用右心室经胸穿刺测压法作为中期筛查是否能提高肺动脉高压大鼠模型末期成功率。本研究将Sprague Dawley大鼠经胸右心室穿刺法测量右心室压,再实施腹主动脉下腔静脉分流术,术后6周,对实验组大鼠再次测量右心室压,淘汰压力值变化不大的模型大鼠;术后11周,对实验组及对照组进行模型成功率的统计,发现实验组成功率明显高于对照组,结果证明右心室经胸穿刺测压法应用于肺动脉高压大鼠模型的中期筛查可明显提高模型末期的成功率,并可作为一种自身前后对照的新方法。     

Ascorbic acid, garlic extract and taurine alleviate cadmium-induced oxidative stress in freshwater catfish (Clarias batrachus)

An experiment was conducted to investigate bioaccumulation potential of cadmium (Cd) and changes in oxidative stress indices in liver and kidney tissues from Cd-exposed catfish (Clarias batrachus) with or without simultaneous treatment of water with ascorbic acid, garlic extract or taurine. C. batrachus (n = 324) with average length of 20 ± 4 cm and weight of 86 ± 5 g were used for the present investigation. Fishes were divided into nine groups (I to IX) each comprising 36 fishes. The fishes of groups II, III, IV and V were challenged with 5 ppm of cadmium chloride monohydrate (CdCl₂.H₂O), whereas groups VI, VII, VIII and IX were exposed to 10 ppm CdCl₂.H₂O solution for a period of 45 days. Group I was kept as negative control and the fishes of this group were maintained in water containing no added Cadmium. Group II and VI were maintained as Cd exposed non treated control to serve as positive controls. Fishes of III and VII, IV and VIII, V and IX received ascorbic acid (5 ppm), extract of dried garlic (5 ppm) or taurine (5 ppm), respectively during the entire experiment period. The concentrations of Cd in liver and kidney increased significantly following exposure to Cd and the level continued to rise with the increase in exposure duration. Treatment of tank water with ascorbic acid, garlic or taurine significantly reduced the Cd concentrations in tissues compared to the positive control group, but the level in Cd exposed groups was greater than the negative control group. Fishes exposed to Cd and treated with ascorbic acid, garlic or taurine had reduced oxidative stress as evidenced from lower concentration of lipid peroxides and higher activities of superoxide dismutase and catalase in liver, kidney and erythrocytes compared to fishes exposed to Cd. The reduction in Cd induced oxidative stress was highest in ascorbic acid treated group followed by garlic and taurine treatment. The results suggest that ascorbic acid, garlic and taurine have potential to reduce tissue accumulation of Cd and associated oxidative stress in freshwater catfish.     

Cadmium in blood and hypertension

OBJECTIVES: This study is to examine the effect of cadmium exposure on blood pressure in Korean general population. METHODS: The study population consisted of 958 men and 944 women who participated in the 2005 Korean National Health and Nutrition Examination Survey (KNHANES), in which blood pressure and blood cadmium were measured from each participant. RESULTS: The mean blood cadmium level was 1.67 microg/L (median level 1.55). The prevalence of hypertension was 26.2%. The blood cadmium level was significantly higher among those subjects with hypertension than those without (mean level 1.77 versus 1.64 microg/dL). After adjusting for covariates, the odds ratio of hypertension comparing the highest to the lowest tertile of cadmium in blood was 1.51 (95% confidence interval 1.13 to 2.05), and a dose-response relationship was observed. Systolic, diastolic, and mean arterial blood pressure were all positively associated with blood cadmium level, and this effect of cadmium on blood pressure was markedly stronger when the kidney function was reduced. CONCLUSIONS: Cadmium exposures at the current level may have increased the blood pressure of Korean general population.     

利用植物化感作用抑制铜绿微囊藻的研究进展

蓝藻水华是一个重要的湖泊环境问题,而铜绿微囊藻是形成水华的主体,因此如何有效控制水华、限制铜绿微囊藻的生长是目前环境领域研究的热点和前沿问题。利用水生植物抑制藻类的生长具有生态安全、快速、高效的优点,对湖泊富营养化的控制具有非常重要的意义。通过介绍植物化感作用的概念、作用途径、抑藻机理及化感作用与铜绿微囊藻的防治关系,展望了利用植物化感作用防治铜绿微囊藻的发展前景。     

Inhibition of biohydrogen production by ammonia

Ammonia inhibition of biohydrogen production was investigated in batch and continuous flow reactors with glucose as a substrate. In batch tests, biohydrogen production rate was highly dependent on pH and ammonia (defined as the sum of NH3 of NH4+ species) concentrations above 2 g N/L. At pH = 6.2, the maximum production decreased from 56 mL/h at 2 g N/L to 16 mL/h at 10 g N/L. At pH = 5.2, production decreased from 49 mL/h (2g N/L) to 7 mL/h (16 g N/L). Hydrogen yield remained relatively constant in batch tests, varying from 0.96 to 1.17 mol-H2/mol-glucose. In continuous flow tests, both hydrogen production rates and yields were adversely affected by ammonia. When the reactor (2.0 L) was first acclimated under batch conditions to a low nitrogen concentration (<0.8 g N/L), H2 production and yields under continuous flow mode conditions were 170 mL/h and 1.9 mol-H2/mol-glucose, but decreased with increased ammonia concentrations up to 7.8 g N/L to 105 mL/h and 1.1 mol-H2/mol-glucose. There was no hydrogen production under continuous flow conditions if the reactor was initially operated under batch flow conditions at ammonia concentrations above 0.8 g N/L. It is concluded that the hydrogen production is possible at high concentrations (up to 7.8 g N/L) of ammonia in continuous flow systems as long as the reactor is initially acclimated to a lower ammonia concentration (<0.8 g N/L).     

新型阻锈剂对钢筋混凝土阻锈作用的研究（Ⅱ）：对砂浆／钢筋界面特性和砂浆性能的影响

用XPS研究了新型阻锈剂DETA-TU在钢筋混凝土中的分布及其对水泥水化作用、新拌砂浆的流动性、硬化砂浆的强度和抗氯离子渗透性的影响,结果表明,DETA-TU能够富集在混凝土/钢筋界面,这对提高DETA-TU的阻锈效果是有益的,DETA-TU对水泥水化有一定的延缓作用,同时又可改善水泥砂浆的流动性,但砂浆的28d强度有所下降,它还能显著提高砂浆的抗氯离子渗透性。     

Inhibition of calcite crystal growth by polyphosphates

The inhibition of calcite crystal growth by pyrophosphate (P(2)O(7)(4-)), tripolyphosphate (P(3)O(10)(5-)), hexametaphosphate (P(6)O(18)(6-)) and binary-polyphosphate blends in calcite-seeded solutions was investigated with various solution compositions using a pH-stat system. In a single polyphosphate system, tripolyphosphate was found to be the strongest inhibitor, followed by pyrophosphate and hexametaphosphate. The inhibition can be explained by the adsorption of polyphosphates on the calcite surface conforming to a simple Langmuir adsorption model. Through a detailed speciation analysis, CaP(2)O(7)(2-) and CaP(3)O(10)(3-) were found to be the primary species of pyrophosphate and tripolyphosphate responsible for adsorption of phosphate on the calcite surface, while the responsible species for hexametaphosphate could not be determined because of a lack of published stability constants. By comparing the equilibrium constants for the adsorption reaction, the inhibitory capabilities of polyphosphates are about two orders of magnitude greater than that of orthophosphate. In binary-polyphosphate systems, the inhibition of calcite crystal growth can be described by a competitive Langmuir adsorption model using the stability constants derived from single solute systems. The inhibitory behavior of commercially available phosphate blends that are marketed to prevent calcite scale formation were demonstrated to be similar to those of laboratory-prepared blends with the same chemical composition.     

Inhibition coefficient (Ki) determination in activated sludge

A method of measurement of the inhibition coefficient, K_i, of chemicals within the activated sludge has been proposed. It makes possible the objective determination of the influence of non-competitive inhibitors on the reaction rate by means of simple respiration rate measurements with the application of a dissolved oxygen meter. The values of K_i for chromium Cr⁶⁺, for cyanide CN^? and for two pesticides—DDVP and des-methyl DDVP was determined.     

热湿交换细菌过滤器联合密闭式吸痰预防呼吸机相关性肺炎

目的:探讨热湿交换细菌过滤器联合密闭式吸痰预防呼吸机相关性肺炎(VAP)的临床效果。方法:选取2010-2011年在本院ICU进行机械通气的158例患者,按照随机数字表法将其分成试验组80例和对照组78例。试验组采用热湿交换细菌过滤器联合密闭式吸痰,对照组采用加热湿化器联合开放吸痰。两组患者均给予化痰止咳、解痉平喘、纠正内环境紊乱、抗感染、每日2次口腔护理和床头抬高30°及营养支持等对症治疗。观察比较两组患者VAP发病率、28 d死亡率、机械通气时间和ICU住院时间的差异。结果:试验组的VAP发病率28.75%明显低于对照组的46.15%,且28 d死亡率18.75%明显低于对照组的34.62%,差异均有统计学意义(P<0.05)。试验组的机械通气时间明显少于对照组,差异有统计学意义(P<0.05),两组ICU住院时间比较差异无统计学意义(P>0.05)。结论:热湿交换细菌过滤器联合密闭式吸痰可以降低VAP发病率、28 d死亡率,缩短机械通气时间,对ICU住院时间无影响。     

咪唑啉硫酸酯盐的缓蚀性能及协同增效作用研究

参照SY/T 5405-1996《酸化用缓蚀剂性能试验方法及评价指标》,采用静态失重法评价咪唑啉硫酸酯盐缓蚀剂1-羟乙基-2-油酸基咪唑啉硫酸酯盐（ISES）与丙炔醇（BCC）、非离子表面活性剂OP-10组成的二元和三元复配缓蚀剂体系对N80钢的缓蚀性能,考察二元和三元复配缓蚀剂体系的协同增效作用。通过动电位极化扫描和电化学阻抗分析对ISES及其复配体系的电化学行为进行研究。     

厌氧消化模型对生化反应抑制形式的模拟

对厌氧消化系统内的抑制动力学进行合理模拟是厌氧工艺顺利运行的前提,也是模型发展和应用的重要部分。ADM1系统分析了几种关键性抑制形式:pH抑制、氢抑制及弱酸和碱抑制。在综合考虑各种抑制动力学的基础上,给出了这些关键性抑制形式的表达公式,用于模拟各种抑制对厌氧反应器内生化反应的影响。     

Inhibition of the flocculation of bacteria by biopolymers

Bacterial flocculation is an important phenomenon in secondary waste treatment. Polymers produced by bacteria control the flocculation process. We used the bacterium Leuconostoc as a model in a study of the effect of bacterial polymers on flocculation.Leuconostoc mesenteroides is known to synthesize extracellular dextran when sucrose is used as a substrate. Dextran is not normally produced by glucose-grown cells. Sucrose-grown cells of Leuconostoc failed to flocculate, while glucose-grown cells formed visible flocs. Removal of dextran from sucrose-grown cells stimulated aggregation. Artificial polymers and clays interacted with stable suspensions of Leuconostoc to yield aggregates. The presence of large quantities of natural or artificial polymers can act to stabilize bacterial suspensions and prevent flocculation.     

酚类化合物对底泥氨氧化活性的抑制作用

利用摇瓶试验考察了18种取代苯酚化合物对底泥氨氧化活性的抑制作用.结果表明:苯酚邻位上的氢被取代时,对底泥氨氧化活性的抑制由强到弱的取代基顺序为-Cl、-CH3或-N02、-H、-OH、-NH2,苯酚对位上的氢被取代时则为-Cl、-NH2或-H、-OH、-NO2;单个-Cl或-CH3取代可增强对底泥氨氧化活性的抑制作用,而增加-Cl或-CH3个数会使抑制作用削弱.取代苯酚类化合物对底泥氨氧化活性的抑制作用强弱与其酸性有线性关系,pKa越小则对底泥氨氧化活性的抑制作用越明显.     

谢君国主任医师治疗高血压病临证经验

谢君国主任医师认为高血压病的主要病机为肝血亏虚、筋脉失养,在临床治疗中应谨守病机,分期论治,中药、西药、针灸相结合,并辅以降压枕、中药足浴等多种综合疗法,以提高降压疗效,防治并发症,改善患者生活质量。附案例1则以资验证。     

厌氧生物处理抑制动力学及其应用

通过对厌氧生物处理动力学模型、厌氧生物处理抑制动力学模型的发展及现状的介绍，综述了盐度、中间产物及重金属对厌氧生物处理的抑制动力学的研究成果。     

Inhibition of calcium phosphate precipitation under environmentally-relevant conditions

Precipitation of Ca phosphates plays an important role in controlling P activity and availability in environmental systems. The purpose of this study was to determine inhibitory effects on Ca phosphate precipitation by Mg(2+), SO(4)(2-), CO(3)(2-), humic acid, oxalic acid, biogenic Si, and Si-rich soil clay commonly found in soils, sediments, and waste streams. Precipitation rates were determined by measuring decrease of P concentration in solutions during the first 60 min; and precipitated solid phases identified using X-ray diffraction and electron microscopy. Poorly-crystalline hydroxyapatite (HAP: Ca(5)(PO(4))(3)OH) formed in control solutions over the experiment period of 24 h, following a second-order dependence on P concentration. Humic acid and Mg(2+) significantly inhibited formation of HAP, allowing formation of a more soluble amorphous Ca phosphate phase (ACP), and thus reducing the precipitation rate constants by 94-96%. Inhibition caused by Mg(2+) results from its incorporation into Ca phosphate precipitates, preventing formation of a well-crystalline phase. Humic acid likely suppressed Ca phosphate precipitation by adsorbing onto the newly-formed nuclei. Presence of oxalic acid resulted in almost complete inhibition of HAP precipitation due to preemptive Ca-oxalate formation. Carbonate substituted for phosphate, decreasing the crystallinity of HAP and thus reducing precipitation rate constant by 44%. Sulfate and Si-rich solids had less impact on formation of HAP; while they reduced precipitation in the early stage, they did not differ from the control after 24 h. Results indicate that components (e.g., Mg(2+), humic acid) producing relatively soluble ACP are more likely to reduce P stability and precipitation rate of Ca phosphate in soils and sediments than are components (e.g., SO(4)(2-), Si) that have less effect on the crystallinity.     

Cadmium toxicity to ringed seals (Phoca hispida): an epidemiological study of possible cadmium-induced nephropathy and osteodystrophy in ringed seals (Phoca hispida) from Qaanaaq in Northwest Greenland

The Greenland marine food chains contain high levels of cadmium, mercury and selenium. Concentrations of cadmium in the kidney of ringed seals (Phoca hispida) from the municipalities of Qaanaaq and Upernavik (Northwest Greenland) are among the highest recorded in the Arctic. The purpose of the study was to determine whether cadmium-induced damage in the kidneys and the skeletal system could be detected among 100 ringed seals from Northwest Greenland. The cadmium concentrations in the kidney cortex ranged from 0 to 248 microg/g wet weight (mean=44.5, N=100) in the 99 kidneys examined. Experience from cadmium-poisoned humans and laboratory mammals indicates that concentrations above 50-200 microg/g wet wt. may induce histopathological changes. Overall, 31 of the ringed seals had cadmium concentrations in the kidney cortex above 50 microg/g wet wt., 11 had concentrations above 100 and one had a concentration above 200 microg/g wet wt. Obvious histopathological changes (categorised mainly as glomerulonephritis) were found in 10 of the seals; however, none of these changes could be attributed to cadmium-induced renal damage (mainly tubulopathy) as described for other species. Damage to the proximal kidney tubules is known to induce demineralisation of the skeletal system (Fanconi's syndrome). Therefore, the three lowest lumbar vertebrae were scanned in 91 seals to measure the content of calcium. The 10 cases of nephropathy could neither be linked to the degree of mineralisation of the skeleton nor to the cadmium concentrations. Furthermore, the degree of mineralisation of the skeleton was not correlated with the cadmium concentration, age or sex. It can therefore be concluded that despite high levels of cadmium, none of the ringed seals showed any signs of cadmium-induced nephropathy or osteodystrophy. This might be explained by the composition of the ringed seals diet, which contains high levels of vitamin D, calcium, phosphorus, zinc, selenium and protein. These elements are all likely to counteract cadmium-induced damage. It is speculated that ringed seal are not particularly vulnerable to osteodystrophy, due to their continuous growth (bone mineralisation) throughout life and the oestrogen hormonal activity of females throughout life.     

Inhibition of nitrification in the packed bed reactors by selected organic compounds

The effect of methanol, acetone, formalin and glucose on the nitrification process in the packed bed reactors has been investigated. For the utilized compounds the inhibition constant K_i was determined according to Dixon's method. The determined values were as follows: methanol K_i = 116.0 mg l^?1; acetone K_i = 804.2 mg l^?1; formalin K_i = 61.5 mg l^?1. The value of K_i for glucose has not been determined because glucose in applied concentration up to 11,325 mg l^?1 had no effect on the nitrification course.