Evaluation of the Suitability of Establishing Biological Exposure Indices of Styrene

BACKGROUND: This study was designed to provide logical backgrounds for the revision of biological exposure indices (BEIs) for styrene exposure in Korea. In order to investigate the correlation between airborne styrene and biological exposure indices, we measured urinary mandelic acid (MA) and phenylglyoxylic acid (PGA) in workers exposed to styrene occupationally, as well as airborne styrene at workplaces. METHODS: Surveys were conducted for 56 subjects. The concentrations of airborne styrene and urinary metabolites of styrene were measured in 36 workers who were occupationally exposed to styrene, and in 20 controls. Air samples were collected using personal air samplers and analyzed by gas chromatography. Urine samples were collected at the end of the shift and analyzed by high performance liquid chromatography. RESULTS: The geometric mean concentration of airborne styrene was 9.6 ppm. The concentrations of urinary MA, PGA, and MA+PGA in the exposure group were 267.7, 143.3, and 416.8 mg/g creatinine, respectively. The correlation coefficients for correlation between airborne styrene and MA, PGA, and MA+PGA were 0.714, 0.604, and 0.769, respectively. The sum of urinary MA and PGA corresponding to an exposure of 20 ppm styrene was 603 mg/g creatinine. CONCLUSION: The correlation of the sum of urinary MA and PGA with airborne styrene was better than the correlation of each individual urinary determinant. It is considered appropriate to amend the concentration of urinary MA+PGA to 600 mg/g creatinine as a BEI, which corresponds to an airborne styrene concentration of 20 ppm in Korea.

Discussion on calculation method of detection limit and quantitative limit of occupational health biological monitoring method / 中华劳动卫生职业病杂志

Objective@#To discuss calculation method of detection limit and quantitative limit of occupational health biological monitoring.@*Methods@#The detection limit and the quantitative limit of phenyl glyoxylic acid and Mandelic acid were calculated by using three different methods of IUPAC, NIOSH and OSHA respectively.@*Results@#The IUPAC, NIOSH and OSHA methods were used to calculate the detection limit and the quantitative limit of the phenyl glyoxylic acid and Mandelic acid, and the results are different.@*Conclusion@#To calculate the detection limit and quantitative limit of occupational health biological monitoring methods, the standard curve method is adopted to ensure that the rate of detection in the vicinity of detection limit and more than 75% of the quantitative limits are used.

Determination of phenylglyoxylic acid and mandelic acid in urine by high performance liquid chromatography method / 中华劳动卫生职业病杂志

Objective@#To revise the standard method for the determination of phenylglyoxylic acid(PGA)and mandelic acid(MA) in urine by ultra-performance liquid chromatography.@*Methods@#The original standard method was evaluated by experiment, and the chromatographic column, the detection limit,quantitation limit and stabilityof the method were studied.@*Results@#The samples were separated by BEH Phenyl(50mm×2.1mm×1.7μm)column and the internal standard working curve method was used. The regression equations were y=3.660 7x+0.066 3 and y=5.161 2x-0.007 3 for MA and PGA respectively. Linear correlation coefficients were 0.999 3 and 0.999 1. Linearity ranges were 0.10-1.00 mg/ml,0.04-0.40 mg/ml. The recoveries of PGA and MA were 91.6%-97.1% and 84.3%-99.0%,the precision were 0.9%-4.6% and 0.5%-1.9%. The detection limit and quantitation limit of the method were 1.1 mg/L and 3.7 mg/L for PGA, 5.4 mg/L and 17.9 mg/L for MA.@*Conclusion@#The method uses the phenyh modified chromatographic column, determines the detection limit. The method can improve quantitation limit, the detection accuracy and meet the detection of occupational population samples.

Study on Analgesic and Anti-inflammatory Effect of Mandelic Acid / 中国药师

Objective: To observe the analgesic and anti-inflammatory effect of mandelic acid. Methods: Fifty Kunming mice were randomly divided into 5 groups:the blank control group (0. 1 ml/10 g), mandelic acid high (300 mg·kg-1), medium (200 mg ·kg-1 ) and low (140 mg·kg-1 ) dose groups, and the positive control ( aspirin) group, ig, qd. The analgesic effect of mandelic acid was observed by writhing test and hot plate method in mice. The ear swelling model caused by dimethyl benzene in mice was a-dopted to observe the analgesic effect. Results:Mandelic acid in each dose group could make the number of writhing in mice signifi-cantly reduced and pain threshold extended, and when compared with the blank control group, the difference was statistically significant (P<0. 01). The writhing times of mice mandelic acid high dose group was fewer than that of the positive control group, and there was no statistically significant between the groups (P>0. 05). In low and medium dose group, the writhing times of mice were more than those of the positive control group, and there was a significant difference between the low dose group and the positive control group( P<0. 05). The pain threshold of the mice in each mandelic acid dose group was higher than that of the positive control group, the pain threshold increased significantly in the high dose group before and after the administration, and the difference was statistically signifi-cant when compared with the positive control group (P<0. 05). The effect of mandelic acid on the ear swelling of mice was not signifi-cant, and when compared with the blank control group, the difference was not significant (P>0. 05). Conclusion:Mandelic acid has significant analgesic effect, while anti-inflammatory effect is not obvious.

Urinary Metabolites and Neurobehavioral Test on Styrene Exposure Workers / 예방의학회지

In order to prepare the fundamental data for the health promotion by assessing the exposure level of styrene, the author determined the concentration of mandelic acid and phenylglyoxylic acid in urine of 42 workers who were exposed to styrene by high performance liquid chromatography and surveyed 16 symptoms, by questionnaire and also tested neurobehavioral test(digit symbol, benton visual retention) in 2 FRP plants of Kyung Nam area from July to September, 1995. Control was sampled by age sex matching method. The concentration of styrene in air was determined by gas chromatography. The results were as follows; 1. Geometric mean concentration of styrene in air was 17.4ppm, geometric mean concentration of mandelic acid(MA) in urine were 404.3mg/g creatinine for exposure group, 46.4mg/g creatinine for control group, geometric mean concentration of phenylglyoxylic acid(PGA) in urine were 57.5mg/g creatinine for exposure group, 9.5mg/g creatinine for control group. Mean concentration of MA and PGA showed statistically significant difference between exposure group and control group(p<0.01). 2. Number of symptom were 2.9 for exposure group, 3.3 for control group, number of digit symbol were 24.1 for exposure group, 32.5 for control group, number of Benton visual retention test were 6.1 for exposure group, 6.0 for control group, respectively. As result of adjusting the education year, number of Benton visual retention test showed statistically significant difference between exposure group and control group(p<0.05). 3. Excellent correlation were observed between environmental styrene exposure and urinary MA(r=0.80), PGA(r=0.73), and MA+PGA(r=0.81).

Styrene in Air and Blood and Mandelic acid in Urine in the Workers exposed to Styrene / 대한산업의학회지

The concentration of styrene in air and in blood and mandelic acid in urine were checked for the 60 workers with normal liver function, exposed to styrene. Styrene in air were sampled with personal air sampler at least 4 hours and analyzed by gas chromatography. Blood and spot urine were collected at the end of shift with a vacuum tube and a plyethylene bottle and analyzed by has chromatography and high performance liquid chromatography. Means of air and blood styrene and urine mandelic acid were 8.16 ppm (geometric mean), 0.199 mg/L, and 0.519 g/g creatinine, respectively. The concentration of styrene in air and mandelic acid in urine were high in the FRP factories and low in polymerization factory. Styrene in blood showed large difference by the working process. Styrene in air showed a good correlation with mandelic acid in urine(r=0.6369) and styrene in blood(r=0.6371). The mandelic acid in urine and styrene in blood corresponded to exposure of 50 ppm styrene were 0.890 g/g creatinine and 0.434 mg/L. However, hippuric acid in urine did not show any correlation with styrene in air. Urine mandelic acid excretion expected ratio showed a tendency to decrease according to obesity index and to increase with alcohol consumption.

The effect of mandelic acid on toxoplasmic pseudocyst in mice / 西安交通大学学报(医学版)

Objective To observe the change of Toxoplasma g ondii tachyziote in pseudocyst. Methods The mice infected by RH Toxoplasma were treated with mandelic acid (200 mg?kg -1 , twice daily) orally or intravenously, then ascites was taken out to smear in 24 h, 72 h and the time of death, with Giemsa dye and transmission electronic microscope (TEM), the survival time was c alculated. Results Under the light microscope, the cell mem brane of tachyzoite was tortous and broken, the bubble and pelletish material we re observed in cytoplasm, cell nucleus was split; but the cell membrane, organs and nucleus were destroyed more obviously under the TEM than those under the lig ht microscope. Meanwhile the living time of mice treated by mandelic acid (8.0 d ays in oral administration group and 6.8 days in intravenous administration grou p) was obviously longer than that in positive control group(5.5 days, P