Follow-up assessment of two cases of trichloroethylene hypersensitivity syndrome: A case report.

The present study aimed to explore the stability, curability and sequelae of cases of Trichloroethylene (TCE) Hypersensitivity Syndrome (THS), and to investigate the causal allergens of THS. Two cases of THS were followed-up in the current study; both cases were healing following glucocorticoid therapy and were discharged >10 weeks prior to follow-up. A questionnaire investigation, health examination and patch test were performed. Allergens of TCE and its metabolites, including chloral hydrate, trichloroethanol (TCOH) and trichloroacetic acid, were applied in the patch test; 4 controls were included. The two subjects were experiencing itching, pigmentation and xerosis of the skin, and had abnormal results in the ophthalmology Schirmer I test and tear break-up time. The body temperature, liver function, superficial lymph nodes, blood, urine routine and autoimmune antibodies of two subjects were shown to be normal, and no new rashes had appeared. All mass concentration of chloral hydrate and TCOH were positive; 5.0% trichloroacetic acid was weakly positive, 0.5% trichloroacetic acid and all mass concentration of TCE were negative. All patch tests were negative in the 4 control subjects. The results suggest that THS was stable following treatment with glucocorticoid therapy. Dry eye syndrome may continue as a sequelae of THS. The patch test demonstrated that the mechanism underlying THS is delayed-type hypersensitivity induced by TCE. In addition, as the hypersensitivity state in a THS rehabilitee could be sustained over a long period of time, it suggests that the metabolites of TCE, not TCE itself, are responsible for THS. Therefore, patients with THS should avoid contact with TCE and its metabolites, and avoid using hypnotic and anticonvulsive drugs containing chloral hydra as the primary ingredient.

[Stressed level of urban vegetation: its assessment based on Hyperion hyperspectral data].

To quickly obtain the information of urban vegetation stressed level is of great significance in maintaining urban vegetation health and improving urban eco-environment. Based on the analysis of stressed vegetations physiological and spectral characters, and by using Hyperion hyperspectral data, 14 hyperspectral vegetation indices related to stress were calculated, and a classifier of urban vegetation stressed level was developed based on this calculation and BP Neural network. The application of this classifier in identifying the vegetation stressed level in a case study area of Guangzhou City showed that the vegetations in commercial and residential districts were apparently experienced higher stress than those in suburban regions, and the stressed level showed a ringy distribution around large pieces of greenbelts. This classifier was able to quickly and accurately identify the vegetation stressed level, and thus, could be used as an effective tool in monitoring urban vegetation stressed condition.

[Degradation of endocrine disruptor atrazine in drinking water by UV radiation].

The degradation of atrazine with low concentration in drinking water by UV radiation was studied. The main influencing factors and degradation mechanism of this technology were discussed. Experimental results show that the photolytic degradation of atrazine by UV radiation alone is very efficient. Under 205 microW/cm2 irradiation intensity, atrazine removal ratio is 92.38% after 120 minutes. The rate of photodecomposition in aqueous solution follows first-order kinetics. The removal ratio of atrazine can be greatly enhanced by increasing the intensity of UV radiation. The initial concentration of atrazine has no effect on the oxidation reaction. The organic matter and various ion in tap water will decrease the degradation rate. The primary degradation pathway is dechlorination. The reaction rate is high. The hydroxylated compound is the major intermediate product. Hydroyatrazine can be further decomposed by UV radiation and form dealkylated derivatives. But the rate of dealkylated reaction is very low. There is intimate relationship between the change of pH in the solution and the formation of intermediate products.

[A clinical analysis of 50 cases of medicament-like dermatitis due to trichloroethylene].

OBJECTIVE: To investigate the clinical manifestations, complications and treatment of medicament-like dermatitis due to trichloroethylene (TCE), so as to provide basis for studying its etiology and mechanism. METHODS: Fifty patients with dermatitis due to TCE from 1997 to 2000 were analysed retrospectively. RESULTS: The occurrence of the dermatitis was not parallel to TCE exposure levels, without significant dose-effect relationship. This disease could be caused by both inhalation and skin exposure. The latency period of TCE dermatitis ranged from 5 to 66 days, and the average was 31.5 d (Medium). The major clinical manifestations included skin lesions, fever, superficial lymph node swelling and liver dysfunction. Infection was the major complication. Glucocorticoid was effective for treatment of this disease. CONCLUSION: The clinical manifestations due to TCE exposure were similar to dermatitis medicamentosa. The major clinical types of TCE dermatitis included exfoliative dermatitis and erythema multiforme. The dermatitis is considered to be mediated by delayed-type (IV) hypersensitivity. The key factors to treat this disease successfully included the use of glucocorticoid in time with sufficient dose and full course, professional skin care, active treatment to protect the liver and to avoid infection.