Urinary excretion of unmetabolized acetone as an indicator of occupational exposure to acetone

Summary Acetone concentrations in urine samples from 28 workers exposed to acetone in a fiber-reinforced plastics factory were determined by directly injecting urine supernate into a gaschromatograph with FID detectors. Acetone concentrations in the urine from ten nonexposed subjects were also determined. The 8-h time-weighted exposure intensity of individual workers was monitored by means of diffusive sampling. Acetone concentration in urine and acetone concentration in the breathing zone showed a linear correlation to each other. The study results indicate that the correlation coefficient is high enough to enable use of the urinary level of acetone as an indicator of occupational exposure to acetone.     

Acetoacetate, acetone, and dibenzylamine (a contaminant in l-(+)-beta-hydroxybutyrate) exhibit direct anticonvulsant actions in vivo

PURPOSE: To investigate whether ketone bodies are directly anticonvulsant. METHODS: We tested the effects of acetoacetate (ACA), acetone, and both stereoisomers, D-(-)- and L-(+), of beta-hydroxybutyrate (BHB) on sensory-evoked seizures in Frings audiogenic seizure-susceptible mice. RESULTS: We found that these ketone bodies, with the exception of the D-(-)-isomer of BHB, were anticonvulsant in this model. Furthermore, with gas chromatography-mass spectrometry, we confirmed that the activity of L-(+)-BHB was due to dibenzylamine, a chemical contaminant. CONCLUSIONS: Our data indicate that the anticonvulsant efficacy of the ketogenic diet may be due in part to the direct actions of ACA and acetone.     

Popliteal lymph node responses to acetone and ethanol differ from those induced by streptozotocin

The popliteal lymph node (PLN) assay was proposed to detect the potential of immunotoxicants for inducing systemic autoimmune-like reactions, but also xenobiotics that are sensitizing or exert immunostimulatory properties. Results on over 100 chemicals, mostly pharmaceuticals, are available with the PLN assay and show many correlations between rodent data and the clinical experience. A major issue is that the mechanisms involved have not been fully elucidated. In order to provide mechanistic clues to improve the predictability of the PLN assay, the effects of streptozotocin (STZ) were compared to those of ethanol and acetone in normal C57Bl/6 mice as well as mice depleted in CD4⁺ or CD8⁺ T-cells by treatment with specific monoclonal antibodies. STZ, ethanol and acetone gave similar positive responses in normal mice. Neither CD4⁺ nor CD8⁺ T-cell depletion influenced the PLN responses to ethanol or acetone, whereas CD8⁺ in contrast to CD4⁺ T-cell depletion abolished the response to STZ. There was an increase in the production of IL-6 and IFN- mRNAs measured by RT-PCR in STZ-, but not in ethanol- or acetone-treated normal mice. The production of TNF, IL-1, IL-1, IL-2R and IL-12 mRNAs was increased whatever the treatment, but increases were 2- to 3-fold greater after STZ than ethanol or acetone. These results suggest that PLN responses to primary irritants such as ethanol and acetone essentially reflect non-specific inflammation, whereas PLN responses to an autoimmunogenic compound such as STZ involve CD8⁺ T lymphocytes and the production of IFN- and IL-6. These findings may prove useful to improve the predictability of the PLN assay.     

工作场所空气中丙酮、丁酮、甲基异丁酮的TWA测定方法

目的 建立工作场所空气中脂肪族酮类化合物丙酮、丁酮、甲基异丁酮的时间加权平均浓度(TWA)气相色谱测定方法。方法通过活性炭管采样,溶剂解吸气相色谱法测定空气中丙酮、丁酮、甲基异丁酮。按照工作场所空气中毒物检测方法研制规范的要求进行实验研究,并对其测定条件和气相色谱条件进行优化选择。结果方法线性范围为丙酮0．02-1．0mg／ml、丁酮0．015-1．5mg／ml、甲基异丁酮0．025-1．0mg／ml。相关系数介于0．9994-0．9998之间。检出限为丙酮20μg/ml,丁酮15μg/ml,甲基异丁酮25μg/ml,相对标准偏差在3．8％-7．0％之间。每100mg活性炭对丙酮的穿透容量为21．6mg、丁酮26．9mg、甲基异丁酮19．8mg。样品在活性炭管中稳定至少可保存7d,方法重现性好。结论此方法的各项指标均达到了工作场所空气中毒物检测方法研制规范的要求,适用于测定工作场所空气中丙酮、丁酮、甲基异丁酮的时间加权平均浓度。由此为2002年新颁布的《工作场所有害因素职业接触限值》(PC-TWA)积累丙酮、丁酮、甲基异丁酮相配套的检验方法。     

Can ageing be prevented by dietary restriction?

This paper disputes the suggestion of Hipkiss [Hipkiss, A., 2006. On the mechanisms of ageing suppression by dietary restriction-is persistent glycolysis the problem? Mech. Ageing Dev. 127, 8-15], according to which dietary restriction by decreasing methylglyoxal production may prevent ageing. A list of arguments is given to support the refusal of hypothesis: (i) it has never been proven that the main source of methylglyoxal is its formation from triose-phosphate intermediates of glycolysis; (ii) the above note particularly applies to pathological conditions as acetone breakdown and amino acid metabolism also come into picture under these circumstances; (iii) glycolysis is of vital importance, thus its inhibition or a sharp restriction of carbohydrate uptake are unlikely beneficial for those tissues that are exclusively dependent on glycolysis in the regard of their energy production. Taken these concerns into account and considered all the promising attempts to influence the toxic effects of methylglyoxal, it is feared that the theory, as it is, cannot offer benefit to prevent ageing.     

Transient receptor potential vanilloid 4–expressing macrophages and keratinocytes contribute differentially to allergic and nonallergic chronic itch

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Antibacterial and anticandidal screening of Tunisian Citrullus colocynthis Schrad. from Medenine

Ethnopharmacological relevance

Resistance to current antibacterial drugs and the rise of opportunistic fungal infections are growing global concerns. Traditional medicine is a potential source of new antibacterials and antifungals. Citrullus colocynthis Schrad. (Cucurbitaceae) endemic in Southern Tunisia, is used in folk medicine against dermatological, gynaecological and pulmonary infections.

Aim of study

To assess in vitro antibacterial and anticandidal activity of aqueous and diluted acetone extracts of Citrullus colocynthis Schrad. MIC and MBC/MFC were determined for plant organs at different maturation stages.

Materials and methods

Citrullus colocynthis Schrad. was harvested and its identification was verified. Aqueous and diluted acetone extracts (from the plant's roots, stems, leaves and three maturation stages of its fruit and seeds) were screened for activity against Gram-negative and Gram-positive bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis)—and various Candida spp. (Candida glabrata, Candida albicans, Candida parapsilosis and Candida kreusei).

Results

All extracts showed activity against all strains. The highest MICs and MBCs/MFCs were obtained from the fruit aqueous extracts (MIC 0.10 mg/ml against Candida albicans and Candida glabrata, 0.20 mg/ml against Escherichia coli and Pseudomonas aeruginosa), lowest activity from the root extracts.

Conclusions

Citrullus colocynthis Schrad. shows antibacterial and anticandidal properties. The folk medicinal use as a broad-spectrum antimicrobial agent is validated.     

小鼠丙酮预处理对丙烯腈氧化应激效应的影响

目的探讨细胞色素P450 2E1诱导对丙烯腈氧化应激效应的影响。方法将40只小鼠(雌雄各半)随机分成4组:空白对照组、(丙酮)诱导组、单纯丙烯腈染毒组(AN)和(丙酮)诱导加丙烯腈染毒组(诱导 AN)。诱导组和诱导 AN组小鼠饮用体积分数为1%的丙酮溶液预处理7 d。4组分别给予丙烯腈0、01、0和10 mg/kg,经腹腔注射染毒24 h后测定小鼠全脑和肝脏的丙二醛(MDA)和谷胱甘肽(GSH)含量以及超氧化歧化酶(SOD)活力。结果4组脑的脏器系数及肝脏的脏器系数性差异无统计学意义;AN染毒组小鼠脑组织中的MDA含量显著高于对照组,诱导 AN组的MDA水平较AN组有所降低;诱导 AN组组小鼠脑组织GSH和SOD含量均高于AN组,其中GSH水平升高具有统计学意义(P<0.05);和空白对照组相比,诱导 AN组、AN组小鼠肝组织中的MDA含量均有所增高,非酶性抗氧化剂GSH含量有所降低,特别是诱导 AN组和AN组相比又有所上升,但差异无统计学意义(P>0.05)。单纯AN组的SOD活力较单纯对照组明显降低(P<0.05),诱导 AN组的SOD活力有所回升,接近单纯对照组水平。结论CYP 2E1诱导表达可减轻丙烯腈的氧化应激损伤,提示丙烯腈原形可能是小鼠引起氧化损伤的主要机制。     

含不同溶剂的碳二亚胺对丙酮基酸蚀冲洗粘接系统粘接性能的影响

目的: 探索水、乙醇、丙酮作选择溶剂时,碳二亚胺(carbodiimide,EDC)对丙酮基酸蚀冲洗粘接系统粘接性能的影响。方法: 选择64颗离体第三磨牙,按照预处理剂种类及是否老化,随机分为8组(n=8),S0、S0a：去离子水;S、Sa：EDC水溶液;E、Ea：EDC乙醇溶液;B、Ba：EDC丙酮溶液。预处理后,采用Prime Bond NT 完成粘接试件制备。S0、S、E、B为即刻组, S0a、Sa、Ea、Ba组进行冷热循环5 000次老化处理。每组随机选取6个试件,测定剪切强度,观察断裂模式,剩余2个试件在SEM下观察粘接界面微观形貌。采用SPSS 20.0软件包对剪切强度进行统计学处理。结果: S组剪切强度大于S0组,Sa组大于S0a,差异有统计学意义(P<0.05),S、E、B组之间差异无统计学意义(P>0.05)。Sa、Ea、Ba组剪切强度依次增大,差异有统计学意义(P<0.05)。EDC、老化、溶剂单独主效应有统计学意义(P<0.05),EDC和老化之间有交互效应(P<0.05)。即刻组断裂模式以混合破坏为主,老化组以界面断裂为主。SEM下观察即刻组混合层均匀完整,S0a组裂纹最大,Ba组仅少量裂纹。结论: 水、乙醇和丙酮作溶剂的EDC预处理,可提高丙酮基酸蚀冲洗粘接系统即刻和老化后粘接强度;丙酮作溶剂时,可最大限度地提高老化后粘接强度。