N-acetylcysteine inhibits chromium hypersensitivity in coadjuvant chromium-sensitized albino guinea pigs by suppressing the effects of reactive oxygen species.

BACKGROUND: Chromium hypersensitivity is an important issue in occupational skin disease. When hexavalent chromium enters the cell, it can be reduced to trivalent chromium, resulting in the formation of reactive oxygen species (ROS). ROS are considered to play an important role in the progression of allergic contact dermatitis. N-acetylcysteine (NAC) could increase glutathione levels in the skin and act as an antioxidant. AIMS: We attempted to demonstrate that NAC could inhibit chromium hypersensitivity in a coadjuvant chromium-sensitized albino guinea pig model by counteracting the formation of ROS. METHODS: We utilized a coadjuvant chromium-sensitized albino guinea pig model to evaluate both the severity of the skin reaction by intradermal and epicutaneous elicitation tests and the sensitization rate of chromium hypersensitivity in NAC-treated and NAC-untreated albino guinea pigs (GP). Furthermore, three ROS parameters, including H(2)O(2,) malondialdehyde (MDA) levels in the skin and the oxygen radical absorbance capacity (ORAC) in plasma, were analyzed in NAC-treated and NAC-untreated coadjuvant chromium-sensitized albino GP. RESULTS: The severity of the skin reaction in the intradermal and epicutaneous elicitation test significantly diminished when the albino GP were treated with a dose of 1200 mg/kg/day of NAC. This dose also significantly decreased the sensitization rate of chromium hypersensitivity. In addition, treatment with 1200 mg/kg/day of NAC significantly reduced the H(2)O(2) and MDA levels in the skin and significantly increased the ORAC in the plasma of albino GP. Therefore, NAC could be a potential chemopreventative agent to prevent the progression of chromium hypersensitivity.

Alterations in health examination items and skin symptoms from exposure to ultra-low humidity.

OBJECTIVES: Several lines of evidence have shown that insufficient humidity could result in health problems but no studies have been performed in ultra-low humidity (ULH) environments. The aims of this study are to investigate the health examination items alterations and skin symptoms of workers exposed to ULH environment based on a longitudinal study design. METHODS: Twelve male ULH (RH = 1.5%) workers and 12 age-sex-matched reference workers were selected. The examination items in blood and urine as well as the skin problems were compared between ULH workers and controls, and between ULH workers in 2000 and 2003. Biochemistry analysis of blood and urine were implemented from annual health examinations. Information on skin symptoms and diseases were obtained from a structured questionnaire in 2000 and 2003. RESULTS: The alterations in mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and total cholesterol in blood analysis and only sediment-WBC in urine analysis were found significantly different in 2000. These changes were almost fully recovered in 2003 although a consistently significant elevation in the urine specific gravity was found during the 3-year follow-up period. Skin disorders, however, showed an earlier elevated itching symptom in lower limb and pretibial that developed to physician-diagnosed contact dermatitis. CONCLUSIONS: Long-term ULH exposure could cause progressive pathological changes in the skin and urine concentration elevation. Because low humidity condition occurs frequently in air-conditioned buildings, the findings of this study suggest the population long-term exposed to low humidity should be cautious about health manifestations living in a low humidity environment. While the indoor environment is equipped with an air-conditioner, continuous monitoring on the humidity is recommended.

Topical exposure to carbon disulfide induces epidermal permeability alterations in physiological and pathological changes.

Carbon disulfide (CS2) has been suggested its possible skin toxicity. Neither a dose-response relationship nor any mechanism of CS2-exposure regarding epidermal permeability alterations has been postulated. The objectives of this study were to evaluate the dose-dependent association and the pathological changes with CS2 topically applied to mouse epidermis. Four concentrations of CS2 (0% (controls), 10%, 15%, and 20% in ethanol) were topically applied to a 1.8 cm2 area of the lateral abdomen of female nude mice for 10 min. Time-series transepidermal water loss (TEWL) profile, morphological examinations by both light microscopy (hematoxylin/eosin stain and Nile Red stain) and electronic microscopy, and lipid analysis by high performance thin-layer chromatography (HPTLC) were used to evaluate the epidermal impairment. We found no recovery occurred within 72 h exposure to 20% CS2 in contrast to substantial recovery found in 10% and 15% CS2-exposure. Clear dose-dependent fashions were shown in TEWL elevations, recovery retardation, and lipid extraction across the ethanol (control), 10%, 15%, and 20% CS2 exposures. Two mechanistic pathways were raised to account for CS2-induced epidermal alterations: intercellular lipid depletion and keratinocyte damage. A study with different test animal species is warranted owing to the discrepancies in epidermis between nude mice and other species.

Effect of occupational exposure to rayon manufacturing chemicals on skin barrier to evaporative water loss.

To evaluate the effects of the occupational exposure to rayon manufacturing chemicals (RMC, containing predominantly carbon disulfide (CS(2)) and minor sulfuric acid) in a rayon factory on the basal transepidermal water loss (TEWL), barrier integrity (BI), and sequential increasing TEWL profiles. Six Thais and five Chinese workers in the spinning department of a rayon manufacturing plant and five healthy unexposed controls were recruited as the test subjects. An area of 4.5 x 5.5 cm on the mid-side of the volar forearm on the right hand was stripped by means of moderate pressure with commercially available adhesive tape by the same technician throughout the experiment. The skin was progressively stripped until glistening. TEWL was measured at every three and five tape strips on the right hand. The corresponding site on the left hand was measured parallel as the self-control. We found significant differences in basal TEWL and in BI between Chinese workers and Chinese controls, and between Thai workers and Chinese workers, respectively. Two-stage patterns of progressive TEWL profiles were found in such a chronic and repeated occupational exposure to RMC containing CS(2). The occupational exposure to RMC could result in the perturbation of the skin barrier function. Basal TEWL might be more sensitive to chronic skin irritant exposure. The TEWL profile achieved to the glistening stage might be necessary to avoid erroneous pattern estimation. Due to the lack of Thais control in this study, the racial difference in response to the RMC warrants further study.

Combined exposure to carbon disulfide and sulfuric acid simultaneously increases the risk of hand dermatitis in rayon industry.

OBJECTIVE: To evaluate the association between hand dermatitis (HD) and occupational exposure to CS(2) and to determine whether combined exposure to CS(2) and H(2)SO(4) exhibits a higher risk of HD. METHODS: In all, 110 subjects from a rayon factory were recruited and their exposure was classified into CS(2) exclusively, H(2)SO(4) exclusively, combined exposure, and nonexposure control based on workers' job characteristics. A dermatologist was designated in the diagnosis of HD on palm and dorsal sites for each subject. Other confounding factors including detergent, glove wearing, and participation in wet work were determined using a person-to-person questionnaire interview from 37 randomly selected subjects. RESULTS: Significant elevated odds ratios (ORs) for HD were found in CS(2) exclusively (44.8, P < 0.01) and combined exposure (49.0, P < 0.001) compared with control. Dose-response trends of ORs for HD were found across control, single exposure, and combined exposure for both CS(2) and H(2)SO(4). CONCLUSIONS: HD could occur resulting from occupational exposure to CS(2) alone. This study was unable to affirm that the exposure to H(2)SO(4) alone is associated with HD due to limited H(2)SO(4) exposure subjects. The combined exposure to both CS(2) and H(2)SO(4) simultaneously could increase the risk of HD. The control remedy in preventing dermal contact with either CS(2) or H(2)SO(4) among the rayon workers should be performed immediately.

The effect of personal factors on the relationship between carbon disulfide exposure and urinary 2-thiothiazolidine-4-carboxylic acid levels in rayon manufacturing workers.

BACKGROUND: Few studies have been conducted to explore how personal factors-personal hygiene, personal protective equipment, and skin exposure affect the exposure-dose relationship in workers exposed to carbon disulfide (CS(2)). METHODS: Personal environmental monitoring of airborne CS(2) and 2-thiothiazolidine-4-carboxylic acid (TTCA) levels in post-shift urine were determined for sixty-five rayon workers. The personal factors affecting the CS(2)-TTCA relationship were measured by questionnaire and dermatological diagnosis. RESULTS: In simple linear regression analyses, we found shower right after work, respirator, gloves, apron, and skin disease were significantly associated with U-TTCA levels among all personal factors. Skin disease was, however, the only personal factor that remained significant throughout multivariate linear regression analyses. CONCLUSIONS: In this study, the personal factor like host's skin disease was found to possibly affect the relations of U-TTCA to the occupational exposure to CS(2). The skin exposure to CS(2) for those who have skin problems on the sites possibly or potentially exposed to CS(2) in the occupational environment such as in the rayon manufacturing process is noteworthy. Workers with susceptible skins should either be assigned to work in areas without contacting hazardous materials directly or required to wear appropriately protective clothing.