Aldehyde dehydrogenase 2 deficiency significantly exacerbates tert-butyl alcohol-induced toxicity in mice

Owing to the use of ethyl tert-butyl ether (ETBE) as a fuel additive, the possible adverse effects of ETBE exposure have become a public concern. Our previous study showed that ETBE-induced toxicity in aldehyde dehydrogenase 2 (Aldh2) gene knockout (KO) mice was caused by its primary metabolite acetaldehyde, which was toxic. However, it is unclear whether tert-butyl alcohol (TBA), another main metabolite of ETBE, plays a role in ETBE-induced toxicity. To investigate this relationship, we analyzed the changes of TBA concentrations in tissues after ETBE exposure, and then evaluated the toxicity after direct TBA treatment in both KO and wild-type (WT) mice. An exposure to 500 ppm ETBE via inhalation resulted in the formation of its three metabolites, TBA, 2-methyl-1,2-propanediol and ethanol, whose concentrations in the liver, brain, fat and testis of male KO mice were significantly higher than the corresponding concentrations observed in male WT mice. Direct treatment to TBA (20 mg/mL of drinking water) caused significant changes in relative organ weights and histopathology, and increased levels of genetic damages in both types of mice. These toxic effects were also seen in KO mice exposed to a lower concentration of TBA (5 mg/mL), which was associated with increased oxidative stress in serum (reduced glutathione and reduced glutathione/oxidized glutathione ratio decreased). Our findings indicate that ALDH2 is involved in the metabolism of ETBE and TBA, and ALDH2 deficiency could greatly increase the sensitivity to TBA-induced toxicity.     

基于中心复合序贯设计法丹参川芎嗪注射液水沉工艺优化

目的基于质量源于设计(QbD)理念和序贯设计法优化丹参川芎嗪注射液前处理过程中的水沉工艺。方法研究联用了鱼刺图法及基于全局式序贯设计的中心复合实验法作为优化方法,在基础实验设计中关键参数维度的轴向方向增加实验点,再进行新的多元线性回归拟合,最终得到了水沉工艺的设计空间并对其进行了验证,同时给出了较为稳健且全面的操作空间。结果根据设计空间,推荐操作空间为水沉体系pH值为3.1～3.4时,加水倍量3.25～5.00,静置时间为7～17 h,静置温度为7℃。结论首次在中药制药过程工艺优化中引入序贯设计法。相较于样本量巨大的均匀空间网格设计、正交设计等实验设计方法而言,序贯设计在实现与前者同样的样本对可行域覆盖程度的基础上,能够有效降低工艺优化实验的工作量,避免样本与人力物力的浪费,同时保证较高的模型预测性能。     

Quantification of rate constants for successive enzymatic reactions with DNP hyperpolarized MR

A kinetic model is provided to obtain reaction rate constants in successive enzymatic reactions that are monitored using NMR spectroscopy and hyperpolarized substrates. The model was applied for simulation and analysis of the successive oxidation of choline to betaine aldehyde, and further to betaine, by the enzyme choline oxidase. This enzymatic reaction was investigated under two different sets of conditions: two different choline molecular probes were used, [1,1,2,2‐D₄, 1‐¹³C]choline chloride and [1,1,2,2‐D₄, 2‐¹³C]choline chloride, in different MR systems (clinical scanner and high‐resolution spectrometer), as well as in different reactors and reaction volumes (4.8 and 0.7 mL). The kinetic analysis according to the model yielded similar results in both set‐ups, supporting the robustness of the model. This was achieved despite the complex and negating influences of reaction kinetics and polarization decay, and in the presence of uncontrolled mixing characteristics, which may introduce uncertainties in both effective timing and effective pulses. The ability to quantify rate constants using hyperpolarized MR in the first seconds of consecutive enzyme activity is important for further development of the utilization of dynamic nuclear polarization‐MR for biological determinations. Copyright © 2014 John Wiley & Sons, Ltd.     

Effect of propanal and diacetyl on quantity of remaining double bonds of chemically cured BisGMA/TEGDMA resins

The aim of the present study was to determine the effect of propanal and diacetyl addition on the quantity of remaining double bonds of chemically cured dental resins. Propanal (propionaldehyde) or diacetyl (2.3-butanedione) was added to monomer mixtures, which were then made chemically curable. The monomer mixtures were varied with respect to content of propanal or diacetyl. Addition of propanal or diacetyl to chemically curable resins resulted in a decrease in the quantity of remaining double bonds from 19.6% to 1.9% and from 19.6% to 11.4%, respectively. A negative correlation of statistical significance was found between content of propanal and quantity of remaining double bonds, while the relationship between content of diacetyl and quantity of remaining double bonds was found not to be linear. Propanal was equally effective in reducing the quantity of remaining double bonds in chemically cured and in the light cured resins studied previously. As regards diacetyl, a more pronounced effect on quantity of remaining double bonds was noted for light cured resins as compared with chemically cured resins. The most likely common reaction mechanism of propanal and diacetyl seemed to be that of chain transfer reactions. Furthermore, analysis of the data indicated a possible additional photoinitiating function of diacetyl.     

肾衰宁胶囊治疗慢性肾衰竭早中期患者的疗效及对肾功能指标的影响

目的:探讨肾衰宁胶囊治疗早中期慢性肾衰竭(CRF)患者的临床疗效及患者肾功能指标的变化。方法:选取2012年3月至2014年12月本院收治的早中期CRF患者82例,随机分为对照组及观察组,每组41例。对照组在常规治疗的基础上给予包醛氧淀粉治疗,观察组在对照组的基础上联合肾衰宁胶囊治疗,2个月为1个疗程,2组患者均连续治疗2个疗程。统计2组患者临床疗效及主要临床症状积分,检测治疗前后2组患者Hb、Alb、24 h UPQ及UA的变化;比较治疗前后2组患者肾功能指标。结果:观察组临床总有效率为85.37%,较对照组的46.34%显著提高(P0.01);与治疗前比较,治疗后对照组仅食少纳呆及肢体麻木积分明显降低,而观察组面色晦暗、食少纳呆、倦怠乏力、腰膝酸软、肢体麻木及口淡不渴积分均明显降低,且显著低于对照组(P0.05或P0.01);与治疗前比较,治疗后对照组Hb、Alb含量明显降低,而观察组无显著变化,且显著高于对照组(P0.05或P0.01);2组患者24 h UPQ及观察组Cys-C、BUN、Scr水平均显著降低,且观察组上述指标均明显低于对照组(P0.01);观察组Ccr明显升高,且明显高于对照组(P0.05或P0.01);2组患者UA含量均无显著变化(P0.05)。结论:肾衰宁胶囊可明显改善早中期CRF患者主要临床症状,阻碍CRF进展,还可调节患者肾脏血流循环,促进患者肾功能恢复,疗效显著优于常规治疗。     

Spinal transient receptor potential ankyrin 1 channel contributes to central pain hypersensitivity in various pathophysiological conditions in the rat

The transient receptor potential ankyrin 1 (TRPA1) ion channel is expressed on nociceptive primary afferent neurons. On the proximal nerve ending within the spinal dorsal horn, TRPA1 regulates transmission to spinal interneurons, and thereby pain hypersensitivity. Here we assessed whether the contribution of the spinal TRPA1 channel to pain hypersensitivity varies with the experimental pain model, properties of test stimulation or the behavioral pain response. The antihypersensitivity effect of intrathecally (i.t.) administered Chembridge-5861528 (CHEM; a selective TRPA1 channel antagonist; 5-10 μg) was determined in various experimental models of pain hypersensitivity in the rat. In spinal nerve ligation and rapid eye movement (REM) sleep deprivation models, i.t. CHEM attenuated mechanical hypersensitivity. Capsaicin-induced secondary (central) but not primary (peripheral) mechanical hypersensitivity was also reduced by i.t. administration of CHEM or A-967079, another TRPA1 channel antagonist. Formalin-induced secondary mechanical hypersensitivity, but not spontaneous pain, was suppressed by i.t. CHEM. Moreover, mechanical hypersensitivity induced by cholekystokinin in the rostroventromedial medulla was attenuated by i.t. pretreatment with CHEM. Independent of the model, the antihypersensitivity effect induced by i.t. CHEM was predominant on responses evoked by low-intensity stimuli (?6 g). CHEM (10 μg i.t.) failed to attenuate pain behavior in healthy controls or mechanical hypersensitivities induced by i.t. administrations of a GABA_A receptor antagonist, or NMDA or 5-HT₃ receptor agonists. Conversely, i.t. administration of a TRPA1 channel agonist, cinnamon aldehyde, induced mechanical hypersensitivity. The results indicate that the spinal TRPA1 channel exerts an important role in secondary (central) pain hypersensitivity to low-intensity mechanical stimulation in various pain hypersensitivity conditions.     

Gender-related differences in hepatic activity of alcohol dehydrogenase isoenzymes and aldehyde dehydrogenase in humans

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH), which are most abundant in the liver, are the main enzymes involved in ethanol metabolism in humans. Gender-related differences in total liver ADH and ALDH activity among different animal species have been observed in many studies. We measured total ADH and ALDH activity, and the activity of class I-IV ADH in the livers of male and female patients. Total ADH and class I and II ADH activities were significantly higher in males than in females (P=0.0052, P=0.0074, P=0.020, respectively). Class III and IV ADH and total ALDH activities were not significantly different between the genders (P=0.2917, P=0.0590, P=0.2940, respectively). The results of our study clearly show that there is a difference in enzymatic activity between male and female patients for those isoenzymes that actively participate in ethanol oxidation in the liver (class I and II ADH), although the main form of ADH in this organ is class III ADH.     

HPLC法测定有瓜石斛中原儿茶酸的含量

目的:建立有瓜石斛中原儿茶酸的含量测定方法.方法:采用高效液相色谱(HPLC)法.色谱柱为Zorbax SB-Aq色谱柱;流动相为乙腈-0.1%磷酸溶液;检测波长为220nm;流速为1.0mL·min-1;柱温为30℃. 结果:原儿茶酸达到基线分离,线性关系良好(r=1.0000);平均加样回收率为101.71%,RSD为2.48%(n=6). 12批市售样品含量在0.0374~0.203mg·g-1范围内,差异相对较大. 结论:该方法灵敏,可靠,可用作有瓜石斛药材的质量评价指标之一.     

The rarity of ALDH+ cells is the key to separation of normal versus leukemia stem cells by ALDH activity in AML patients

To understand the precise disease driving mechanisms in acute myeloid leukemia (AML), comparison of patient matched hematopoietic stem cells (HSC) and leukemia stem cells (LSC) is essential. In this analysis, we have examined the value of aldehyde dehydrogenase (ALDH) activity in combination with CD34 expression for the separation of HSC from LSC in 104 patients with de novo AML. The majority of AML patients (80 out of 104) had low percentages of cells with high ALDH activity (ALDH⁺ cells; <1.9%; ALDH‐rare AML), whereas 24 patients had relatively numerous ALDH⁺ cells (≥1.9%; ALDH‐numerous AML). In patients with ALDH‐rare AML, normal HSC could be separated by their CD34⁺ALDH⁺ phenotype, whereas LSC were exclusively detected among CD34⁺ALDH^? cells. For patients with ALDH‐numerous AML, the CD34⁺ALDH⁺ subset consisted mainly of LSC and separation from HSC was not feasible. Functional analyses further showed that ALDH⁺ cells from ALDH‐numerous AML were quiescent, refractory to ARA‐C treatment and capable of leukemic engraftment in a xenogenic mouse transplantation model. Clinically, resistance to chemotherapy and poor long‐term outcome were also characteristic for patients with ALDH‐numerous AML providing an additional risk‐stratification tool. The difference in spectrum and relevance of ALDH activity in the putative LSC populations demonstrates, in addition to phenotypic and genetic, also functional heterogeneity of leukemic cells and suggests divergent roles for ALDH activity in normal HSC versus LSC. By acknowledging these differences our study provides a new and useful tool for prospective identification of AML cases in which separation of HSC from LSC is possible.