The Relationship Between Hippuric Acid in Blood Plasma and Toluene Concentration in the Air of Workplace / 예방의학회지

OBJECTIVES: This study was undertaken to evaluate correlation between the levels of hippuric acid in blood plasma (HAP) and those of toluene concentration in the workplace air. METHODS: Study subjects were composed of two groups; 21 workers who were occupationally exposed to toluene and 25 rural-area residents who were not exposed to any known occupational toluene source, as an exposed group and a reference group, respectively. Mean age and work duration of the exposed was 42 years and five years, respectively. Mean age of the reference was 42 years. To determine toluene concentrations in the workplace air, air sampling has been conducted for more than six hours using a personal sampler, and analyzed by a gas chromatography-flame ionization detector. Concentrations of hippuric acid in biological samples were determined by a high performance liquid chromatography-ultraviolet detector. RESULTS: Geometric mean(geometric standard deviation) of HAP and hippuric acid in urine(HAU) for the exposed was 1.39(2.21) mg/L and 2.77(1.46) g/L, respectively, which were significantly different from those of the reference [HAP, 0.45(2.94); HAU, 0.37(0.45)]. Toluene concentration in the workplace air was 86.92(range: 45.18~151.23) ppm. The level of HAP or HAU was significantly correlated (r=0.70 and r=0.63, respectively) with that of toluene in the workplace air. The estimated regression equation was logHAP(mg/L)=-3.60+1.93 log(toluene, ppm) or logHAU(g/L)=-0.85+0.67 log(toluene, ppm). The magnitude of correlation was further enhanced when analyzing relationship between toluene concentrations lower than 100 ppm and its corresponding HAP levels. CONCLUSION: Overall, plasma hippuric acid levels were well correlated with toluene concentrations in the workplace air, and a statistically significant correlation was observed for the samples with toluene concentration lower than 100 ppm.

Plasma Malondialdehyde, alpha-tocopherol and Erythrocyte Superoxide Dismutase Activity with Blood Level of Heavy Metals in Welders / 대한산업의학회지

We investigated the association between the oxidative stress and the concentration of heavy metals in blood among welders. The study subjects were male manual CO2 welders(N=127) exposed to several heavy metals. The age distribution was from 20 to 63 (GM=33.7) and the geometric mean(GM) of work duration was 4.2 years. We analyze the level of blood lead, cadmium, managese and chromium which was related with the oxidative stress in the animal studies. Blood selenuim, plasma malondialdehyde (MDA), plasma alpha-tocopheol and orythrocyte superoxide dismutase (SOD) were analyzed as biological markers of the oxidative stress. The results of univariate analysis showed that the plasma MDA was significantly correlated with D-tocopherol (r=0.327) and blood selenium (r=0.313) concentration. But we could not find out any relationship between the erythrocyte SOD activities and those metal concentrations. Neither smoking nor alcohol consumption was related to the level of heavy metals and the oxidative stress biomarkers. As the results of multiple regression analysis with stepwise selection method, 1) the change of MDA level were dependant with the level of alpha-tocopherol and blood selenium concentration (R2=19.7), 2) the plasma alpha-tocopherol level was dependant with MDA and blood chromium concentration (R2=15.6), 3) in case of erythrocyte SOD activity, only the duration of work was significantly selected.

Lipid Peroxidation and Antioxidants in Workers Exposed to Lead / 예방의학회지

This study was started to find out if plasma malondialdehyde(MDA), alpha-tocopherol and erythrocyte superoxide dismutase(SOD) activity could be markers of biological activity resulting from exposed to lead in workers. Blood samples were randomly obtained from lead -exposed workers(n=29), CO2 welders(n=60) and office workers(n=60). We used whole blood to analyse blood lead with atomic absorption spectrophotometer. Superoxide dismutase activity in erythrocyte was measured with spetrophotometer. MDA and alpha-tocopherol in plasma were measured with high performance liquid chromatography. Lead-exposed workers was significantly high in blood lead concentration(29.37 ng/dl) compared with welders(6.42 ng/dl) and office workers(5.01 ng/dl). The level of plasma MDA was significantly higher in the lead-exposed workers(1.87 nmol/g cholesterol) than the welders(1.41 nmol/g cholesterol) and office workers(1.41 nmol/g cholesterol). Erythrocyte SOD activity in lead-exposed workers(56.80 U/g Hb) was significantly increased than those of welders(37.63 U/g Hb) and office workers(20.47 U/g Hb). The plasma alpha-tocopherol level of lead-exposed workers(4.93 ng/g cholesterol) was statistically different from welders(4.25 ng/g cholesterol) and office workers(4.28 ng/g cholesterol). Neither age nor smoking was related to SOD or MDA level. Blood lead was significantly correlated with erythrocyte SOD activity(r=0.405), plasma MDA(r=0.296) and alpha-tocopherol(r=0.207). Plasma MDA was also significantly correlated with SOD (r=0.217). In multiple regression analysis, the change of MDA and SOD activity level related to the blood lead concentration. These results suggested that the increase of plasma MDA and erythrocyte SOD activity in lead-exposed workers had a close relationship with the oxidative stress induced by lead.

A Study of the Correlation Between the Activity of Erythrocyte Pyrimidine 5'-Nucleotidase and Urinary N-Acetyl-beta-D-Glucosaminidase in Lead Exposed Workers / 대한산업의학회지

In this study, we measured the activity of the erythrocyte pyrimidine 5'-nucleotidase (P5N) and urinary N-acetyl-beta-D-glucosaminidase (NAG) from 154 workers exposed to lead and 43 workers not exposed. We analyzed the correlation of the P5N activity and NAG activity with other biological exposure indices of lead such as blood lead (PbB) and zinc protoporphyrin (ZPP). The measurement was performed by using high performance liquid chromatography (HPLC), spectrophotometer and atomic absorption spectrophotometer. The results are as follows: 1. The mean value of P5N activity for workers exposed to lead was 9.50+/-.13 micromol uridine/hr/g Hb and 11.60+/-.2 micromol uridine/hr/g Hb for workers not exported. The P5N activity showed a normal distribution, but the other indices of lead showed logarithmic normal distributions. 2. The P5N activity and ZPP were decreased as PbB wag increased. But the NAG activity had no correlation with changes of PbB. 3. The correlation coefficients of the P5N activity with other biological exposure indices of lead such as PbB, ZPP, NAG activity were -0.72, -0.55, and 0.05, respectively. We speculated that the P5N activity can be used as a reliable biological exposure index of lead but NAG activity can be used as a biological management index of lead.