We studied the association of nonspecific bronchial hyperresponsiveness with general characteristics, exposure concentration, respiratory symptoms, chest x-ray findings, past histories and pulmonary function. We determined bronchial hyperresponsiveness by methacholine challenge test. And we conducted a respiratory symptom questionnaire and performed spirometry on 111 workers occupationally exposed to isocyanates in various industries. About 21.6% of subjects had bronchial hyperresponsiveness. No significant differences were observed between the hyperresponsive and non-responsive group with respect to age, sex, employment period, height, and smoking histories cough and breathlessness were significantly associated with the bronchial hyperresponsiveness. The hyperresponsive group had more experience of bronchitis and asthma in the past than the non-responsive group. The lower FEV1 and FEV1 % were closely related with bronchial hyperresponsiveness. Bronchial hyperrespoosiveness seems to be associated with some of respiratory symptoms, past histories and pulmonary function parameters in workers exposed to isocyanates.
Asthma ; Bronchitis ; Cough ; Employment ; Isocyanates* ; Methacholine Chloride ; Occupations ; Surveys and Questionnaires ; Smoke ; Smoking ; Spirometry ; Thorax

OBJECTIVETo establish the method of detecting the concentrations of methyl isocyanate (MIC) in air of workplaces with high performance liquid chromatographic (HPLC).

METHODSSamples are collected by XAD-7 tubes coated with 1-(2-pyridyl) piperazine (1-2PP). Samples are desorbed with acetonitrile (ACN) and analyzed by high performance liquid chromatography (HPLC) using a fluorescence detector.

RESULTSThere was a linear relationship within the range of 0.01 ∼ 10 µg/ml, and the detection limit was 5.3×10(-4) µg/ml. The minimum detectable concentration was 0.01 µg/ml, and the lowest detected concentration was 3.3×10(-3) mg/m(3). The relative standard deviation was 2.2% ∼ 5.3%. The average desorption efficiency was 90% and the sampling efficiencies were 100%. The samples could be stored for 10 days in cold storage condition.

CONCLUSIONThe present method could meet with the requirements of Guide for establishing occupational health standards-Part4 Determination methods of air chemicals in workplace and be feasible for determination of MIC in workplace air.

BACKGROUND: Although occupational asthma is defined as a reversible airway obstruction causally related to exposure in the working environment, many occupational asthmatics complain of asthmatic symptoms despite avoidance of the causative agent. Subjects and methods. Twenty-nine patients with occupational asthma who had been confirmed by specific bronchial challenge with reactive dye or isocyanates and had avoided the causative agent for at least 6 months were included in this study. A questionnaire about asthmatic symptoms and medication requirements, a lung functiontest, and a methacholine bronchial provocation test were performed. RESULTS: Asthmatic symptoms at follow-up were remitted in seven (41.2%) isocyanate-induced asthmatics, but none with reactive dye-induced asthma were remitted. At follow-up, the symptom-medication score and FEV1 were significantly improved in isocyanate-induced asthmatics than in those with reactive dye-induced asthma, but the geometric mean of PC20-methacholine was not different between the two groups. Among 17 isocyanate-induced asthmatics, a duration from symptom onset to avoidance was significantly shorter in the remission group than in the nonremission group, although the symptom-medication scores, FEV1 (% predictive value) and logPC20-methacholine at an initial diagnosis, and follow-up period defined as duration from avoidance to follow-up, showed no difference between the two groups. CONCLUSION: The outcome of occupational asthma may be determined by the causative agents and the duration from onset of asthmatic symptoms to avoidance.
Airway Obstruction ; Asthma ; Asthma, Occupational* ; Bronchial Provocation Tests ; Diagnosis ; Follow-Up Studies ; Humans ; Isocyanates ; Lung ; Methacholine Chloride ; Prognosis ; Surveys and Questionnaires

OBJECTIVE: To investigate the prevalence of airway hyperresponsiveness induced by isocyanate at one petrochemical industry complex in Yeochon, Korea. METHOD: Questionnaires, allergic skin prick test, toluene diisocyanate (TDI)-specific IgE, and non-specific airway hyperresponsiveness (AHR) were studied in 73 exposed workers and 27 control subjects. Methacholine challenge tests were done and bronc hial responsiveness (BR index) was defined as log (% fall of FEV1)/ log (last concentration of methacholine +10). RESULTS: Twenty-three workers (31.5% ) had respiratory symptoms, 21 had nasal symptoms, and eight had skin symptoms. Exposed workers with respiratory symptoms (n=22) had significantly higher BR index than those without them (0.82+/-0.06 vs 0.60+/-0.02, p<0.05). Exposed workers tended to have higher BR index than controls (0.67+/-0.03 vs 0.62+/-0.02). Three exposed workers had PC20 methacholine <2.0 mg/ml. There were no significant differences in atopy score between exposed workers and controls (p>0.05). Specific IgE antibodies were found in 19.7% of exposed workers. FEV, showed a significant negative correlation with BR index (r =-0.25, p<0.05). Poor correlation was noted between BR index and atopy, smoking status, or exposure duration. CONCLUSION: These findings suggest that workers exposed to isocyanates are at higher risk of airway hyperresponsiveness.
Antibodies ; Immunoglobulin E ; Isocyanates* ; Korea ; Methacholine Chloride ; Plants* ; Prevalence ; Skin ; Smoke ; Smoking ; Toluene 2,4-Diisocyanate ; Surveys and Questionnaires

PURPOSE: To determine the incidence and epidemiological characteristics of work-related asthma in Korea. METHODS: During 2004-2009, the Korea Work-Related Asthma Surveillance (KOWAS) program collected data on new cases of work-related asthma from occupational physicians, allergy and chest physicians, regional surveillance systems, and workers' compensation schemes. The incidence was calculated on the basis of industry, occupation, sex, age, and region. In addition, the distribution of causal agents was determined. RESULTS: During the study period, 236 cases of work-related asthma were reported, with 77 cases from more than 1 source. A total of 22.0% (n=52) were reported by occupational physicians, 52.5% (n=124) by allergy and chest physicians, 24.2% (n=57) by regional surveillance systems, and 43.2% (n=102) by workers' compensation schemes. The overall average annual incidence was 3.31 cases/million workers, with a rate of 3.78/million among men and 2.58/million among women. The highest incidence was observed in the 50-59-year age group (7.74/million), in the Gyeonggi/Incheon suburb of Seoul (8.50/million), in the furniture and other instrument manufacturing industries (67.62/million), and among craft and related trades workers (17.75/million). The most common causal agents were isocyanates (46.6%), flour/grain (8.5%), metal (5.9%), reactive dyes (5.1%), and solvents (4.2%). CONCLUSIONS: The incidence of work-related asthma in Korea was relatively low, and varied according to industry, occupation, gender, age, and region. Data provided by workers' compensation schemes and physician reports have been useful for determining the incidence and causes of work-related asthma.
Asthma* ; Coloring Agents ; Female ; Humans ; Hypersensitivity ; Incidence ; Interior Design and Furnishings ; Isocyanates ; Korea ; Male ; Occupations ; Seoul ; Solvents ; Thorax ; Workers' Compensation

The biocompatible hydrogel was fabricated under suitable conditions with natural dextran and polyethylene glycol (PEG) as the reaction materials. The oligomer (Dex-AI) was firstly synthesized with dextran and allylisocyanate (AI). This Dex-AI was then reacted with poly (ethyleneglycoldiacrylate) (PEGDA) under the mass ratio of 4∶6 to get hydrogel (DP) with the maximum water absorption of 810%. This hydrogel was grafted onto the surface of medical catheter via diphenyl ketone treatment under ultraviolet (UV) initiator. The surface contact angle became lower from (97 ± 6.1)° to (25 ± 4.2)° after the catheter surface was grafted with hydrogel DP, which suggests that the catheter possesses super hydrophilicity with hydrogel grafting. The evaluation after they were implanted into ICR rats subcutaneously verified that this catheter had less serious inflammation and possessed better histocompatibility comparing with the untreated medical catheter. Therefore, it could be concluded that hydrogel grafting is a good technology for patients to reduce inflammation due to catheter implantation, esp. for the case of retention in body for a relative long time.
Allyl Compounds ; Animals ; Biocompatible Materials ; Catheters ; Dextrans ; Hydrogel, Polyethylene Glycol Dimethacrylate ; Hydrogels ; Hydrophobic and Hydrophilic Interactions ; Isocyanates ; Polyethylene Glycols ; Rats ; Water

A novel diisocyanate, i. e. lysine ethyl ester diisocyanate (LDI), was prepared by the present authors. Poly (epsilon-caprolactone) (PCL) (M(n) = 2000) was used for reacting with LDI to form prepolymer, and then the chain was extended with butanediol (BDO) to form polyurethane (PU). PU was characterized by gel permeation chromatography, FTIR and 1H-NMR. Mechanical properties test revealed that PU possesses excellent tensile strength. Hydrolytic degradation and enzymatic degradation of PU films showed that PU is biodegradable. Finally, vascular scaffold of PU was fabricated by electrospinning. Morphological and biomechanical properties of scaffold were examined. The tensile strength was 8MPa, suture retention strength 12N, porosity 75% and burst pressure strength 150-170 kPa. Cytotoxicity and cell adhesion showed that PU scaffolds are biocompatible. These results demonstrate that PU vascular scaffolds possess excellent physical strength and biocompatibility and can be developed as substitutes for native blood vessels.
Biocompatible Materials ; chemical synthesis ; chemistry ; Blood Vessel Prosthesis ; Isocyanates ; chemistry ; Lysine ; analogs & derivatives ; chemistry ; Polyesters ; chemistry ; Polyurethanes ; chemical synthesis ; chemistry ; Tissue Engineering ; methods ; Tissue Scaffolds

Adopting the two-step method and changing the proportion between PEG (Polyethylene glycol) and PTMG (poly (tetrahydrofuran), we used the MDI (4,4'-diphenylmethane diisocyanate) and short chain extender BDO (1,4-butanediol) as hard segment, the PTMG and PEG as soft segment, and hence prepared a series of polyether-based thermoplastic polyurethanes. FTIR showed the structure character of these polyurethanes. The determination of mechanics property and water contact angles revealed their good mechanics properties and hydrophilicity. Blood compatibility was evaluated by hemolysis test and platelet adhesion test, which revealed their good hemocompatibility. So those polyurethanes may be of wide application in the future.
Animals ; Biocompatible Materials ; chemical synthesis ; chemistry ; Butylene Glycols ; chemistry ; Isocyanates ; chemistry ; Materials Testing ; Polyethylene Glycols ; chemistry ; Polymers ; chemistry ; Polyurethanes ; chemical synthesis ; chemistry ; Rabbits

Animals ; Female ; Isocyanates ; toxicity ; Male ; Malondialdehyde ; metabolism ; Mice ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase ; metabolism ; Pregnancy ; Prenatal Exposure Delayed Effects ; Superoxide Dismutase ; metabolism ; Testis ; drug effects ; metabolism

The development of a serological marker for early diagnosis of isocyanate-induced occupational asthma (isocyanate-OA) may improve clinical outcome. Our previous proteomic study found that expression of vitamin D-binding protein (VDBP) was upregulated in the patients with isocyanate-OA. In the present study, we evaluated the clinical relevance of VDBP as a serological marker in screening for isocyanate-OA among exposed workers and its role in the pathogenesis of isocyanate-OA. Three study groups including 61 patients with isocyanate-OA (group I), 180 asymptomatic exposed controls (AECs, group II), 58 unexposed healthy controls (NCs, group III) were enrolled in this study. The baseline serum VDBP level was significantly higher in group I compared with groups II and III. The sensitivity and specificity for predicting the phenotype of isocyanate-OA with VDBP were 69% and 81%, respectively. The group I subjects with high VDBP (> or = 311 microg/ml) had significantly lower PC20 methacholine levels than did subjects with low VDBP. The in vitro studies showed that TDI suppressed the uptake of VDBP into RLE-6TN cells, which was mediated by the downregulation of megalin, an endocytic receptor of the 25-hydroxycholecalciferol-VDBP complex. Furthermore, toluene diisocyanate (TDI) increased VEGF production and secretion from this epithelial cells by suppression of 1,25-dihydroxycholecalciferol [1,25(OH)2D3] production. The findings of this study suggest that the serum VDBP level may be used as a serological marker for the detection of isocyanate-OA among workers exposed to isocyanate. The TDI-induced VEGF production/secretion was reversed by 1,25(OH)2D3 treatment, which may provide a potential therapeutic strategy for patients with isocyanate-OA.
Adult ; Animals ; *Asthma/blood/chemically induced/pathology ; Cell Line ; Epithelial Cells ; Female ; Gene Expression/drug effects ; Humans ; Isocyanates/toxicity ; Male ; Middle Aged ; *Occupational Diseases/blood/chemically induced/pathology ; Rats ; Toluene 2,4-Diisocyanate/toxicity ; Vitamin D-Binding Protein/*blood