China ; epidemiology ; Hexanes ; toxicity ; Humans ; Occupational Diseases ; epidemiology ; Trichloroethylene ; toxicity

Trichloroethylene (TCE) is a widely used organic solvent and an important industrial material. Due to mass production and use, and improper waste disposal, TCE has become a common environmental contaminant, so there is a wide range of occupationally and environmentally exposed population. Occupational and environmental exposure to TCE can produce toxic effects on multiple organs and systems. This paper is a review of the immunotoxicity, reproductive toxicity, neurotoxicity, teratogenic effect and other non-carcinogenic toxic effects of TCE from the aspects of epidemiological study, experimental evidence on animals and toxic mechanisms.
Animals ; Environmental Exposure ; Humans ; Occupational Exposure ; Solvents ; toxicity ; Trichloroethylene ; toxicity

Trichloroethylene is commonly used as an industrial solvent and degreasing agent. The clinical features of acute and chronic intoxication with trichloroethylene are well-known and have been described in many reports, but hypersensitivity syndrome caused by trichloroethylene is rarely encountered. For managing patients with trichloroethylene hypersensitivity syndrome, avoiding trichloroethylene and initiating glucocorticoid have been generally accepted. Generally, glucocorticoid had been tapered as trichloroethylene hypersensitivity syndrome had ameliorated. However, we encountered a typical case of trichloroethylene hypersensitivity syndrome refractory to high dose glucocorticoid treatment. A 54-year-old Korean man developed jaundice, fever, red sore eyes, and generalized erythematous maculopapular rashes. A detailed history revealed occupational exposure to trichloroethylene. After starting intravenous methylprednisolone, his clinical condition improved remarkably, but we could not reduce prednisolone because his liver enzyme and total bilirubin began to rise within 2 days after reducing prednisolone under 60 mg/day. We recommended an extended admission for complete recovery, but the patient decided to leave the hospital against medical advice. The patient visited the emergency department due to pneumonia and developed asystole, which did not respond to resuscitation.
Dermatitis, Occupational/*etiology ; Fatal Outcome ; Humans ; Hypersensitivity/*etiology ; Male ; Middle Aged ; Occupational Exposure/*adverse effects ; Solvents/*toxicity ; Trichloroethylene/*toxicity

OBJECTIVESTo study the contact allergenic activities of trichloroethylene (TCE) and its three metabolites trichloroacetic acid, trichloroethanol and chloral hydrate.

METHODSA modified guinea pig maximization test (GPMT) was adopted. The skin sensitization (edema and erythema) was observed in trichloroethylene, trichloroacetic acid, trichloroethanol, chloral hydrate and 2,4-dinitrochlorobenzene.

RESULTSThe allergenic rate of TCE, trichloroacetic acid and 2,4-dinitrochlorobenzene was 71.4%, 58.3% and 100.0% respectively, and that of trichloroethanol and chloral hydrate was 0%. The mean response score of TCE, trichloroacetic acid and 2,4-dinitrochlorobenzene was 2.3, 1.1, 6.0 respectively. The histopathological analysis also showed an induction of allergenic transformation in guinea pig skin by both TCE and trichloroacetic acid.

CONCLUSIONTCE appears to be a strong allergen while trichloroacetic acid a moderate one. On the other hand, both trichloroethanol and chloral hydrate are weak sensitization potentials. Immunologic reaction induced by TCE might be postulated as the pathological process of this illness. Consequently, it is suggested that in the mechanism of Occupational Dermatitis Medicamentose-Like (ODML) induced by TCE, the chemical itself might be the main cause of allergy. As one of its metabolic products, trichloroacetic acid might be a subordinate factor.

Allergens ; toxicity ; Animals ; Chloral Hydrate ; toxicity ; Dermatitis, Allergic Contact ; etiology ; immunology ; Dermatitis, Irritant ; etiology ; immunology ; Ethylene Chlorohydrin ; analogs & derivatives ; toxicity ; Guinea Pigs ; Skin ; drug effects ; immunology ; Toxicity Tests ; Trichloroacetic Acid ; toxicity ; Trichloroethylene ; metabolism ; toxicity

OBJECTIVETo observe the change of caspase-8, caspase-9 activity and apoptosis rates in the process of trichloroethylene-induced damage in keratinocytes, and explore the tentative mechanism of apoptosis.

METHODSHuman keratinocytes were exposed to 0.125, 0.250, 0.500, 1.000 and 2.000 mmol/L trichloroethylene for 4, 8, 12 and 24 h. The inhibitive groups were pretreated with 100 micromol/L Z-LEHD-FMK (a specific inhibitor of caspase-9) for 1 h, and were stimulated with 2.000 mmol/l TCE for 12 h. MTT assay was used to detect the viability of different cells; The activity of caspase were calculated according to spectrophotometry; Change of the apoptotic rates was assessed by flow cytometer (FCM) after double-stained with Annexin V-FITC and propidium iodide (PI).

RESULTS(1) The minimum effective concentration for cell viability reduction was 0.125 mmol/L at 12 h and the shortest time required to produce a change was 4 h at a concentration of 2.000 mmol/L (compared with control group, P < 0.01). Cell viability in all the groups markedly decreased from 12 h to 24 h (P < 0.05). (2) The activity of caspase-8 in the various dosage groups at different times had no statistical difference compared with the control group, P > 0.01. (3) At 8 h, 1.000 and 2.000 mmol/L TCE groups could significantly enhance caspase-9 activity (P < 0.05). The caspase-9 activity in all the groups showed differences and was significantly higher than those of control cells when time was over 12 h (P < 0.05). (4) After exposing to different dosages of TCE for 12 h, the rate of apoptosis rose to (80.43 +/- 4.21)% with the increase of dosage, compared with the control group, (9.40 +/- 2.98)%, which showed a dose-effect relationship. (5) The cells pre-treated with caspase-9 inhibitor resulted in a decrease in the caspase-9 activity and apoptosis rates (compared with 2.000 mmol/L TCE exposed group, P < 0.01). However, there was no statistical significance in comparison with the control group (P > 0.05).

CONCLUSIONCaspase-9 may be an important mediator of apoptosis in keratinocytes induced by trichloroethylene.

Apoptosis ; drug effects ; Caspase 8 ; metabolism ; Caspase 9 ; metabolism ; Cells, Cultured ; Humans ; Keratinocytes ; drug effects ; enzymology ; pathology ; Trichloroethylene ; toxicity

Animals ; DNA Damage ; Dose-Response Relationship, Drug ; Isotope Labeling ; Male ; Phosphorus Radioisotopes ; analysis ; Rats ; Rats, Sprague-Dawley ; Trichloroethylene ; toxicity

OBJECTIVETo investigate the apoptosis-inducing effect of trichloroethylene (TCE) on cultured normal human epidermis keratinocytes (NHEK) in vitro.

METHODSNR(50) values (the concentration of neutral red absorbed is reduced to 50%) of TCE on NHEK were assayed by neutral red uptake (NRU), and the administered dose of TCE was determined. Lipid peroxidation (LPO) and oxidative stress were assessed by measurement of malondialdehyde (MDA) contens and superoxide dismutase (SOD) activity. Transmission electron microscope (TEM) were used to observe morphologic changes, flow cytometer (FCM) was used to measure DNA contents and calculate cell apoptosis rate and proliferation index (PI).

RESULTSNR(50) values of TCE on NHEK was found to be 4.53 mmol/L (95% CI: 3.92-5.13 mmol/L). The increase in MDA content and inhibition of SOD activity in a concentration-dependent manner were shown after NHEK was treated with a series of dose of TCE 4 h later, and typical morphologic changes of apoptosis were also observed by TEM examination. FCM analysis revealed a sub-G(1) peak in the apoptotic cells. The apoptotic rate in TCE 0.125, 0.500, 2.000 mmol/L exposed groups (31.83%, 38.63%, 44.35%, respectively) were significantly higher than that in blank control (18.42%), while PI in TCE 0.125, 0.500, 2.000 mmol/L group (3.26%, 2.48%, 2.07%, respectively) were significantly lower than that in blank control (4.99%).

CONCLUSIONTCE may induce apoptosis of cultured NHEK in vitro, and inhibit cell proliferation through lipid peroxidation and oxidative stress.

Apoptosis ; drug effects ; Cells, Cultured ; Epidermis ; cytology ; drug effects ; Humans ; Keratinocytes ; drug effects ; Lipid Peroxidation ; Oxidative Stress ; Trichloroethylene ; toxicity

OBJECTIVETo establish the association between genetic polymorphisms of HLA-DMA and HLA-DMB and risk of developing trichloroethylene-induced medicamentosa-like dermatitis (TIMLD).

METHODSSixty-one cases were medically confirmed to have been affected with TIMLD and 60 controls were selected from exposed workers who were free from TIMLD. The TIMLD cases and controls were similar in terms of age, sex, and duration of exposure. DNA was extracted both from the TIMLD cases and controls, HLA-DMA and HLA-DMB loci were amplified by using Touchdown PCR, and the alleles and genotypes were confirmed by restriction fragment length polymorphism (RFLP) and direct sequencing. Finally, the frequencies of HLA-DMA and HLA-DMB variants were compared between the two groups.

RESULTSThe results showed that the frequency of HLA-DMA*0101 and HLA-DMB*0103 alleles was significantly increased in TIMLD patients than in controls (71.3% vs. 55.0% for HLA-DMA*0101; P<0.05) (11.5% vs. 3.3% for HLA-DMB*0103; P<0.05). In addition, the frequency of HLA-DMA*0102-*0102 homozygous genotype was also significantly higher in the controls than in the patients (25.0% vs. 8.2%, P<0.05), whereas the frequency of heterozygous HLA-DMB *0101-*0102 genotype was lower in the patients in comparison with the controls. Conclusion The polymorphisms of HLA-DM may be associated with the susceptibility to TIMLD.

Alleles ; Dermatitis, Contact ; genetics ; Genetic Predisposition to Disease ; HLA-D Antigens ; genetics ; Humans ; Polymorphism, Genetic ; Polymorphism, Restriction Fragment Length ; Trichloroethylene ; toxicity

OBJECTIVETo explore the mechanism of occupational medicamentosa-like dermatitis (OMDT) induced by trichloroethylene (TCE) and some immunity indexes in workers occupationally exposed to TCE.

METHODSThe blood samples from 8 cases with medicamentosa-like dermatitis in 1st, 2nd, 3rd, 4th and 5th weeks after admitting to hospital were examined for liver function, immunoglobulin and some complement indexes. Thirty nine workers occupationally exposed to TCE were investigated for urinary TCE and some immuno-complement indexes. The TCE concentrations of air in workplaces were monitored.

RESULTSC3d-CIC and C3 of patients before admission were (92.86 ± 44.80) mg/L and 0.91 ± 0.19 mg/L, respectively. C3d-CIC and C3 of patients before discharge were (52.41 ± 17.75) mg/L and (1.14 ± 0.22) mg/L, respectively. There were significant differences between admission and discharge (P < 0.05). The average TCE concentration in 4 workplaces was (351.96 ± 36.72) mg/m(3), which was higher than the occupational exposure limits (OELs). The number of workers exposed to the TCE concentration-time weighted and TCA in urine over OELs were 28.21% and 56.41% of total subjects, respectively. The serum IgG and CIC levels of patients before discharge were (10.03 ± 1.21) mg/L and 103.50 ± 29.17 mU/L, which were significantly lower than those (17.21 ± 1.85) mg/L and (227.46 ± 111.67) mU/L of patients before admission (P < 0.01).

CONCLUSIONThe type II and III hypersensitivity may be associated with OMDT and the organ injure induced by TCE.

Adolescent ; Adult ; Complement System Proteins ; immunology ; Dermatitis, Occupational ; immunology ; Female ; Humans ; Male ; Occupational Exposure ; Trichloroethylene ; toxicity ; Young Adult

OBJECTIVETo analyse the epidemiological distribution of dermatitis patients in hospital and provide basis for studying the basic conditions and the prevention of dermatitis especially TCE-induced dermatitis in Baoan District of Shenzhen City.

METHODSAll dermatitis patients in hospital in Baoan District from 1992 to 2006 were descriptively analysed.

RESULTSThere were 645 dermatitis patients in hospital in Baoan District. The total number of patients is tended to rise in recent years. The main age group of 16 approximately years old, followed by 26 approximately years old, the majority are workers. The clinical diagnosis are allergic dermatitis, drug-induced dermatitis, TCE-induced dermatitis. Compared with other dermatitis, women are more than men in TCE-induced dermatitis (P < 0.05). The risk of hepatic dysfunction in TCE-induced dermatitis was significantly greater than other dermatitis (P < 0.05). It is mainly distributed in electronic, metal, electroplating industry.

CONCLUSIONThe TCE-induced dermatitis was one of the main occupational hazards in Baoan district. To strengthen self-protection awareness of workers, pay more attention to early work observed and occupational screening in key industries and trades workers, reduce opportunities for occupational exposure, all above can effectively reduce the occurrence of TCE-induced dermatitis.

Adolescent ; Adult ; Aged ; China ; epidemiology ; Dermatitis ; epidemiology ; Dermatitis, Contact ; epidemiology ; Female ; Humans ; Inpatients ; Male ; Middle Aged ; Trichloroethylene ; toxicity ; Young Adult