Quantitative analysis of urinary glycine conjugates by high performance liquid chromatography: excretion of hippuric acid and methylhippuric acids in the urine of subjects exposed to vapours of toluene and xylenes

Summary A new method for the direct determination of hippuric acid (HA) and o-, m- and p-methylhippuric acids (MHAs) in the urine, metabolites of toluene and o-, m- and p-xylenes by high performance liquid chromatography (HPLC) is described. A stainless-steel column packed with silica gel having dinitrophenyl residue and a mixed solution of methanol/water/acetic acid (80/20/0.2) containing tetra-n-butylammonium bromide (0.2% w/v) as mobile phase was used. Concentrations of HA and MHAs were estimated from their peak height at a wave length of 225 nm. Urine can be analyzed directly without solvent extraction or pretreatment to obtain complete separation of HA and o-, m- and p-MHAs. Urine samples from male workers exposed to toluene or xylenes were analyzed for HA or MHAs. The urinary levels of HA and MHAs increased by exposure to toluene and xylenes in proportion to the environmental concentrations of the solvents, although there is a considerable variation in metabolite concentrations. The slope of regression line between toluene and HA and that between m-xylene and m-MHA were similar. The urinary concentrations of HA and MHAs corresponding to 100 ppm (TLV) of toluene was 2.35 g/g creatinine and that of m-MHA corresponding to 100 ppm (TLV) of m-xylene was 2.05 g/g creatinine. The warning levels of the urinary metabolite concentrations of a group of workers and that of an individual worker corresponding to TLV of organic solvent concentration is discussed.     

Volatile organic compounds in the blood of persons in Kuwait during the oil fires

Between March and November of 1991, approximately 9000 workers from 43 different countries battled the burning oil wells in Kuwait. To document the exposure of persons in Kuwait during the oil well fires to volatile organic compounds (VOCs), we obtained samples of blood from 14 U.S. personnel in Kuwait City in May of 1991 (group I) and 40 American firefighters working in the oil fields in October of 1991 (group II). Concentrations of VOCs in group I and group II were compared with those of a random sample of 114 persons in the United States (reference group). The median concentrations of VOCs in group I were equal to or lower than those in the reference group. We found significant differences between the median concentrations of several VOCs in group 11 and the reference group. Median levels of ethylbenzene were about 10 times higher among group II than among the reference group (0.53 g/I vs 0.052 g/l). Median levels of benzene, m-/p-xylene, o-xylene, styrene, and toluene among group II were more than double those of the reference group. Although firefighters had higher median concentrations of VOCs than the reference group, those American personnel in Kuwait not involved in fighting the oil fires had concentrations of VOCs comparable to those in the reference group. Blood VOC measurements indicate a significant increase in exposure to VOCs in firefighters, but do not demonstrate this in personnel in Kuwait City.     

二甲苯对不同年龄大鼠脑组织形态学及神经细胞凋亡的影响

目的　探讨年龄对二甲苯神经毒作用的影响。方法　采用 Ｈ Ｅ 染色法和 Ｔ Ｕ Ｎ Ｅ Ｌ 技术对不同月龄大鼠的脑组织病理形态学和神经细胞凋亡情况进行了研究。结果　二甲苯５００ ｍ ｇ／ｋｇ 染毒后,２ 月龄组较８ 月龄组大鼠脑组织形态学改变相对严重,２ 月龄组染毒大鼠神经细胞凋亡的发生率为（１ ．５３ ±１ ．０６） 个／ 视野,明显高于同龄对照组的（０ ．９３ ±０ ．７５） 个／ 视野, Ｆ＝ １２ ．６５９ ６ , Ｐ＜ ０ ．００１ ;８ 月龄组染毒大鼠的神经细胞凋亡率为（１ ．６５ ±１ ．１１） 个／ 视野,明显高于同龄对照组的（１ ．１５ ±１ ．０７） 个／ 视野, Ｆ＝ ６ ．２６３ ３ , Ｐ＜ ０ ．０５ 。结论　低龄大鼠对二甲苯的神经毒作用更为敏感     

风热流浸膏解热镇痛和抗炎作用的实验研究

目的观察风热流浸膏的抗炎、镇痛和解热作用。方法采用二甲苯致小鼠耳肿胀、角叉菜胶致大鼠足趾肿胀的模型观察抗炎作用;采用乙酸和热刺激致小鼠疼痛的模型观察镇痛作用;采用2,4-二硝基酚和酵母粉致大鼠发热的模型观察解热作用。结果风热流浸膏能减轻小鼠耳肿胀和大鼠足趾肿胀炎症反应,缓解乙酸和热刺激所致疼痛,降低2,4-二硝基酚和酵母粉致大鼠发热的体温。结论风热流浸膏具有显著的抗炎、镇痛和解热作用。     

Control of workers’ exposure to xylene in a pesticide production factory

Background:

Acute and chronic exposure to xylene can result in a range of negative health effects. However, xylene is widely used and emitted in the air of workplaces.

Objectives:

To evaluate xylene vapor concentrations to guide the design and evaluation of a local exhaust ventilation (LEV) system to reduce exposure in a pesticide production factory.

Method:

A real time volatile organic compound (VOC) monitor was used to determine the workers’ time-weighted average (TWA) exposure. A LEV system was designed, and then, workers’ exposure to xylene vapor was evaluated.

Results:

We found that worker’s exposure to xylene (4.7±5.5 ppm) was lower than the standards recommended by the American Conference of Governmental Industrial Hygienists (ACGIH) and the Occupational safety and health administration (OSHA). Despite the low TWA exposures, the short-term exposures for some workers were higher than STEL levels. Three canopy hoods were designed and installed with capture velocities of 0.508 m second⁻¹ and duct velocity of 10.16 m second⁻¹.

Conclusion:

We found that an exhaust ventilation system had a significantly reduced occupational exposure to xylene vapor.     

常用溶剂型胶粘剂中苯、甲苯、二甲苯的气相色谱测定法

目的建立适用于同时测定常用溶剂型胶粘剂中苯、甲苯、二甲苯含量的气相色谱分析方法.方法用二甲基甲酰胺溶解胶粘剂样本,用聚乙二醇(wax)毛细管色谱柱,氢火焰检测器气相色谱法对苯系物进行分离,保留时间定性,峰面积定量.结果胶粘剂中苯、甲苯、二甲苯在7.33～146.50、7.23～144.50、7.21～144.20 mg/L范围内,该方法具有良好的线性(均r=0.999),苯、甲苯、二甲苯的方法检出限分别为0.22、0.24、0.24 mg/L.样品加标回收率分别为96.45%～100.09%,98.45%～100.76%,97.81%～100.14%.RSD为1.60%～2.85%.结论该方法适用于同时测定常用溶剂型胶粘剂中苯、甲苯、二甲苯的检测,方法准确、可靠.     

Inhibition of chemically induced inflammation and pain by orally and topically administered leaf extract of Manihot esculenta Crantz in rodents

The aqueous leaf extract of Manihot esculenta Crantz (MELE) is being used orally and topically in traditional African medicine for the treatment of inflammation and pain, and claimed to be safe. The anti-inflammatory effects of MELE (100-400mg/kg, p.o. or 1-4%, w/w in petroleum jelly, topically) were tested against carrageenan-induced paw oedema in rats as well as against xylene-induced ear oedema in mice. The analgesic effect of MELE (100-400mg/kg, p.o. or 1-4%, w/w in petroleum jelly, topically) was tested against acetic acid-induced (20mul, 0.6%, v/v in normal saline, i.p.) and acetylcholine-induced (8.3mg/kg, i.p.) mouse writhing models. At 100-400mg/kg, p.o. and 1-4% (w/w), topically, MELE produced significant inhibitions of carrageenan-induced rat paw oedema and xylene-induced ear swelling in mice. Effects produced by MELE were significantly higher than those produced by indomethacin (10mg/kg, s.c. or 1%, w/w in petroleum jelly) in the anti-inflammatory models. For the analgesic effect, MELE (100-400mg/kg, orally) and (1-4%, w/w, topically), like aspirin (100mg/kg, i.p.) exhibited significant (P<0.05) inhibition of acetic acid- and acetylcholine-induced mouse writhing tests, compared to untreated control. Effects produced by MELE were significantly lower than those produced by aspirin (100mg/kg, i.p.) in the analgesic models, except for the topically administered extract on acetylcholine-induced pain. Acute oral administration up to 10g/kg did not cause death within 14 days, but mortalities were produced in i.p. administered extract with LD(50) of 2.5+/-0.3g/kg. Based on these, the extract may contain orally safe, topically and orally effective anti-inflammatory and analgesic principles, which justify its use in traditional African medicine.     

川贝母止嗽颗粒对小鼠耳廓肿胀抑制作用的研究

目的研究川贝母止嗽颗粒对小鼠耳廓肿胀的抑制作用。方法通过二甲苯致小鼠耳廓肿胀急性炎症动物模型,评价川贝母止嗽颗粒的抗炎效果。结果与空白对照组比较,川贝母止嗽颗粒高、中、低剂量组均能够显著抑制二甲苯致小鼠耳廓肿胀（P〈O．01或P〈O．05）。结论川贝母止嗽颗粒具有一定的对抗小鼠耳廓急性炎症作用。     

混苯接触对男工性机能的影响

为评价混苯接触对男工性机能的影响，选取从事造漆、皮鞋粘胶等已婚接触男工50名，非混苯作业从事行政后勤人员38名作对照。结果显示，混苯作业对接触男工性机能的影响主要表现为性支持续时间缩短（P＜0.05），勃起异常、射精异常、性欲异常的出现率虽呈增高趋势，但无统计学的差异（P＞0.05）。     

装修所致室内空气污染状况调查

[目的]了解室内装修对室内空气质量的影响，并进行室内环境污染状况科学评价，对消除、控制室内空气污染提供科学依据和指导方法。[方法]于2004年9月至2005年8月对河南省濮阳市35户装修居室和8处办公（公共）场所室内空气中甲醛、苯、甲苯、二甲苯、氡（Rn）浓度进行检测。[结果]35户居室内5种主要污染物的点超标率和户超标率分别为：甲醛49．62％和74．29％、苯5．43％和14.3％、甲苯11．29％和17．14％、二甲苯10．48％和17．14％、氡均不超标，以甲醛的超标率最高。8处办公（公共）场所中，只有甲醛超标，超标率为37．04％。不同功能居室房间甲醛超标率分别为：客厅50．0％、卧室50．7％、书房58.3％、餐厅33.3％、厨房50．0％。[结论]室内装修对室内空气污染严重，是引起室内空气质量下降的主要原因。5种污染物检测结果表明：甲醛是造成室内环境污染的主要因素，其次是苯系物。