饮用水电化学法杀菌副产物三氯甲烷生成因素的研究

目的　了解电化学杀菌过程中副产物三氯甲烷的生成因素。方法　取滤后水 (三层滤料快滤池后、投放液氯前 )分别以石墨、Ti(基 ) - Ti为电极 ,配制不同 SO42 - 和 Cl- 浓度的实验水样 ,调节不同槽电流密度 ,电解不同时间后 ,取样分析 ,考察在不同条件下 CHCl3 的产生情况。结果　采用 Ti(基 ) - Ti电极的间歇电解过程中产生的 CHCl3 比采用石墨电极时多 ,且电流密度越大 ,产生的 CHCl3 越多。加入微量电解质 Na2 SO4对 CHCl3 的产生量无显著影响 ;加入微量电解质 Na Cl,〔CHCl3 〕随〔Cl- 〕的增大而增大。结论　在饮用水电解杀菌时应采用石墨电极 ,电解时间不宜超过 10分钟 ,电流密度宜 1m A/ cm2 ,以使 CHCl3 的生成量最小     

急性扩容性血液稀释电解质的影响

目的对比观察乳酸钠林格液和万汶在术前急性扩容性血液稀释前后电解质的变化。方法20例病人随机分为万汶组(组1)和乳酸钠林格液组(组2)。病人入室开放静脉后分别给予两组液体15 ml/kg,30 min输注完毕。分别于输液前后抽血查血常规、电解质。结果两组扩容前后MAP、HR无明显变化,血K+稀释性降低。组1扩容后HCT下降明显,血Na+明显增加,但仍在正常范围之内。组2扩容后HCT明显下降,血Na+在正常范围之内。结论万汶扩容效果优于乳酸钠林格液,但可致血Na+升高,血K+稀释性降低。     

Effect of amiloride on electrolyte concentrations and rubidium uptake in principal and mitochondria-rich cells of frog skin

The role of mitochondria-rich cells (MR cells) in transepithelial Na transport was investigated by determining electrolyte concentrations and Rb uptake in individual cells of frog skin epithelium using electron microprobe analysis. Measurements were performed under control conditions and after blocking the transepithelial Na transport with amiloride. Under control conditions, Na and Cl concentrations of MR cells scattered much more than those of principal cells and ranged from a few up to more than 30 mmol/kg wet weight. Rb uptake from the basal side into individual MR cells also showed a large variation and was, on the average, much less pronounced than into the principal cells. In principal cells, amiloride reduced the Na concentration and Rb accumulation. In contrast, no effect was observed upon electrolyte concentration and Rb uptake of MR cells. Rb uptake was correlated to the Na concentration of MR cells both under control conditions and after amiloride. It is concluded that, in contrast to the principal cells, MR cells are not involved in amiloride-sensitive transepithelial Na transport and that their Na/K-pump activity is very low.     

Blutdruck,relatives Körpergewicht,Alkoholkonsum und Elektrolytausscheidung in der BRD und der DDR: Die Intersalt-Studie

Summary The relationships between body mass index (BMI) and age, alcohol consumption, 24-hr urinary electrolyte excretion, and BP were studied in 588 subjects from three German centers participating inIntersalt, a highly standardized, previously reported protocol. Men and women aged 20–59 were sampled in Bernried, FRG; Cottbus, GDR; and Heidelberg, FRG. The subjects from the three centers did not differ in BMI, level of education, physical activity, cigarette- or alcohol-consumption patterns, or urinary Cl excretion. Mean Na excretion was 167, 147, and 172 mmol/24 hr in Bernried, Cottbus, and Heidelberg, while mean K excretion was 72, 55, and 73 mmol/24 hr, respectively. The excretion of these electrolytes was significantly lower in Cottbus than in Bernried or Heidelberg. BMI increased progressively in men with age; in women BMI plateaued until the 5th decade, after which it increased to equal that of men. In individual centers, the excretion of electrolytes was correlated with BML Sodium and chloride excretion were highly correlated. The data from each individual center were fitted to a multiple regression model. Age, BMI, sex, and alcohol consumption entered the model.

     

Intracellular potentials of microperfused human sweat duct cells

Intracellular potentials of cells from isolated segments of microperfused human sweat ducts were measured in order to determine the electrical profiles of these cells under resting, transporting, and inhibited conditions. Even though the cells are relatively small (ca. 6–8 m), continuous recordings of intracellular potentials from the same impalement were stable for up to 2 h. In the resting condition in normal Ringer's solution when the lumen of the duct was collapsed and not perfused, the intracellular potential measured across the basal membrane was 34.6±1.5 mV (n=31; mean±SE). In the same bathing medium, when the duct lumen was also perfused with normal Ringer's solution, the basolateral membrane potential (V _b), the apical membrane potential (V _a) and transepithelial potential (V _t) was –33.8±0.47 mV, –23.7±0.48 mV and –9.6±0.9 mV (n=73), respectively. The average input impedence (R _i) of these cells was 19.6±0.4 M (n=36). The frequency distribution ofV _b was unimodal suggesting that only one functional cell type exists in this tissue. Amiloride (0.1 mM) in the lumen hyperpolarized bothV _a andV _b by –40.5±3.6 mV and –33.2±3.7 mV (n=15), respectively, with a slight but significant increase inR _i (15%), while abolishingV _t. Removing luminal Cl^– depolarizedV _a by +37.0±4.2 mV and hyperpolarizedV _b by –19.0±4.2 mV (n=11). Removing Cl^– from the bath hyperpolarizedV _a by –3.3±2.3 mV and depolarizedV _b by +24.3±2.7 mV (n=15). Ouabain caused an initial fast depolarization (+8 mV) followed by a prolonged slow depolarization ofV _b, and an increase inR _i of about 84%. These results not only provide the first electrical profile of the human sweat duct tissue, but they also show that its cell membrane potentials are unusually low. This unusual property of this epithelium appears to be due to the combination of a significant Na⁺ conductance at the apical membrane and a remarkably high tissue Cl^– conductance.     

METABOLIC AND CNS CORRELATES OF COGNITIVE DYSFUNCTION WITH RENAL FAILURE

Experimental uremia in primates has been demonstrated to produce severe decrements in psychological functions which are related to the accumulation of toxic metabolites in blood. More recent neurophysiological research has referred uremic encephalopathy to disrupted sodium-potassium exchange in uremic brain. The present clinical investigations have found decrements in cognitive functioning with repeated testing in patients maintained on intermittent hemodialysis, which were correlated with plasma concentrations of potassium and creatinine. Power Spectral Density analyses of EEG indicated a shift to lower frequencies in these patients as compared to control subjects. No significant departure from normal functioning has been determined in patients receiving renal transplant tested within 60 days post-surgically.     

Directed sampling for electrolyte analysis and water content of micro-punch samples shows large differences between normal and ischemic rat brain cortex

Changes in sodium, potassium, and water content in brain tissue are important in the progression of pathology that follows ischemic stroke. Determining these parameters regionally in rodent models of experimental ischemia has been limited because typical tissue weights of more than 35 mg are too large. Identifying ischemic tissue to direct tissue sampling towards ischemic cortex is also represents a difficult generally unresolved area. We suggest that larger differences between normal and ischemic cortex of sodium, potassium, and water content than previously observed can be obtained from directed sampling of 2-mg brain tissue in a model of focal cerebral ischemia. In five rats, the middle cerebral artery and both common carotid arteries were occluded for 4.9+/-0.13 h (mean+/-SEM). Punch-sampling of 1-mm diameter tissue cores for water content (H(2)O%) by the wet-dry method, and [Na(+)] and [K(+)] by flame photometry, was guided by the observation of a subtle change in the surface reflectivity of ischemic cortex of quickly dried, 20-microm frozen brain sections, that was confirmed by MAP2 immunohistochemistry. The ratio of the lesion areas as determined by the reflective change and MAP2 immunoreactivity was 0.96+/-0.03 (n=5). In ischemic cortex H(2)O% was 79.9%+/-0.8%, [Na(+)] was 550+/-25 mEq/kg dry-weight, and [K(+)] 94.2+/-19.2 mEq/kg dry-weight (n=5), all significantly different from the values in border zone cortex, and in cortex contralateral to ischemic cortex and border zone (for all samples n=60, mean wet weight 2.037+/-0.046 mg). Differences between ischemic and normal cortex were 5.4+/-1.1%, 317+/-21 mEq/kg dry-weight, -304+/-27 mEq/kg dry-weight (n=5) for H(2)O%, [Na(+)], and [K(+)]. These differences between ischemic and normal cortex are 1.4-2.5, 1-3.11, and 1.4-3.5 times greater, respectively, than previous results obtained using samples weighing 35 mg or more. These results extend the association of sodium and potassium with ischemic brain edema in the rodent model, and show that these classical measurements can keep pace with the regionality of histochemical and morphological methods.     

Proton pump inhibitors linked to hypomagnesemia: a systematic review and meta-analysis of observational studies

Abstract

Background: The reported risk of hypomagnesemia in patients with proton pump inhibitor (PPI) use is conflicting. The objective of this meta-analysis was to assess the association between the use of PPIs and the risk of hypomagnesemia. Methods: A literature search of observational studies was performed using MEDLINE, EMBASE and Cochrane Database of Systematic Reviews from inception through September 2014. Studies that reported odd ratios or hazard ratios comparing the risk of hypomagnesemia in patients with PPI use were included. Pooled risk ratios (RRs) and 95% confidence interval (CI) were calculated using a random-effect, generic inverse variance method. Results: Nine observational studies (three cohort studies, five cross-sectional studies and a case-control study) with a total of 109,798 patients were identified and included in the data analysis. The pooled RR of hypomagnesemia in patients with PPI use was 1.43 (95% CI, 1.08–1.88). The association between the use of PPIs and hypomagnesemia remained significant after the sensitivity analysis including only studies with high quality score (Newcastle–Ottawa scale score?≥?8) with a pooled RR of 1.63 (95% CI, 1.14–2.23). Conclusions: Our study demonstrates a statistically significant increased risk of hypomagnesemia in patients with PPI use. The finding of this meta-analysis of observational studies suggests that PPI use is associated with hypomagnesemia and may impact clinical management of patients who are taking PPIs and at risk for hypomagnesemia related cardiovascular events.     

不同真空采血管和标本放置时间对电解质检测结果的影响

[目的]探讨真空采血管和标本放置时间的不同对急诊患者电解质检测结果产生的影响。[方法]使用肝素锂抗凝管和普通促凝真空管,同时抽血后分别于放置0.5、1、2 h时进行检测,观察两者不同时刻检测的结果。[结果]在0.5和1 h时,血浆组中K+和Na+浓度均明显低于血清组(P0.05)。随着标本放置时间的延长,血浆组中K+和Na+浓度有增高趋势,并在2 h时差异有统计学意义(P0.05)。血清组中K+、Na+和Cl-的浓度不同时刻无明显差异(P0.05),但随着放置时间的延长,血浆组和血清组的CO2水平均明显下降,且差异有统计学意义(P0.05)。[结论]使用不同的真空采血管对电解质的检测结果有影响。随着标本放置时间的延长,血浆组K+和Na+的测量值升高,血浆组和血清组CO2的测量值则都下降。