Role of vitamin D-binding protein in isocyanate-induced occupational asthma

Sung-Ho Kim,최길순,Young-Hee Nam,김주희,허규영,김승현,박상면,박해심 생화학분자생물학회 2012 Experimental and molecular medicine Vol.44 No.5

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 (≥ 311 μg/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.

Transition-metal-free synthesis of aromatic amines <i>via</i> the reaction of benzynes with isocyanates

Seo, Jeong Hoon,Ko, Haye Min Elsevier 2018 Tetrahedron letters: the international organ for t Vol.59 No.7

<P><B>Abstract</B></P> <P>An unexpected reaction between benzynes and isocyanates to generate aromatic amines has been developed under transition-metal-free conditions. The <I>in situ</I> prepared anions formed through cleavage of the NC bond in isocyanates, reacted with aryne precursors to afford various aniline derivatives in moderate to excellent yield and tolerated various substituents on the <I>o</I>-silyl aryl triflate and the isocyanate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Transition-metal-free and ligand-free reaction. </LI> <LI> Facile approach to construct carbon-nitrogen bond utilizing aryne precursors and isocyanates. </LI> <LI> Unexpected cleavage of NC bond in isocyanates to afford anions. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Isocyanates 폭로 근로자들의 기관지 과민성

최경숙,김규상,최병순,최정근,이세휘,문영한,Choi, Kyeong-Sook,Kim, Kyoo-Sang,Choi, Byung-Soon,Choi, Jung-Keun,Lee, Se-Hui,Moon, Young-Hahn 대한예방의학회 1996 Journal of Preventive Medicine and Public Health Vol.29 No.1

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 $FEV_1\;and\;FEV_1%$ were closely related with bronchial hyperresponsiveness. Bronchial hyperresponsiveness seems to be associated with some of respiratory symptoms, past histories and pulmonary function parameters in workers exposed to isocyanates.

Inadvertent topical exposure to isocyanates caused damage to the entire eyeball

Hyoung Jun Koh,Soon Hyun Kim,Oh Woong Kwon 대한안과학회 2000 Korean Journal of Ophthalmology Vol.14 No.1

Isocyanates are part of a group of important chemicals necessary in the production of adhesives, synthetic rubbers, and a variety of plastics. They are known to have minimal toxic effects when administered locally. However, we experienced a case of damage involving the entire eyeball in a person who accidentally exposed his eye to isocyanates. The patient presented with inflamed conjunctiva, and shrunken cornea and sclera, with focal atrophic changes in the iris. The lens and vitreous were opacified. After removal of the lens and vitreous, there were large areas of atrophic retina and areas of retinal necrosis with holes. We found that locally absorbed isocyanates can cause damage to the entire eyeball. Therefore, we recommend that if there is any evidence of isocyanate penetration, early vitrectomy should be performed to help in determining the extent of retina damage and to decrease the amount of toxic substance in the vitreous.

Covalent Attachment of Aromatic Diisocyanate to the Sidewalls of Single‐ and Double‐Walled Carbon Nanotubes

Jung, Yong Chae,Muramatsu, Hiroyuki,Hayashi, Takuya,Kim, Jin Hee,Kim, Yoong Ahm,Endo, Morinobu,Dresselhaus, Mildred S. WILEY‐VCH Verlag 2010 European journal of inorganic chemistry Vol.2010 No.27

<P><B>Abstract</B></P><P>We carried out covalent functionalization of single‐ and double‐walled carbon nanotubes (SWNTs and DWNTs) comparatively by using isocyanate chemistry. The introduction of aromatic diisocyanate on the sidewalls of the tubes was verified by the strong IR peak around 2272 cm<SUP>–1</SUP> arising from the NCO asymmetric stretching mode, by the intensified sp<SUP>3</SUP> peak at 285.2 eV in the C1s photoemission spectra, and by a typical TEM image of the amorphous‐like coating. The suppression of the optical properties in a covalently isocyanate‐functionalized SWNT is due to a breakdown of the van Hove singularities, whereas the strong optical activity in a covalently isocyanate‐functionalized DWNT originates from the geometrically shielded inner tubes. The chemically active isocyanate groups at the end of the phenyl diisocyanate that are covalently attached to the sidewalls of the DWNTs will allow us to utilize isocyanate chemistry in synthesizing functional organic–inorganic hybrid materials as well as high‐performance polymer composites.</P>

공기중 이소시아네이트류의 측정 및 분석방법에 관한 비교연구

변혜정,윤충식,백남원 한국환경보건학회 1996 한국환경보건학회지 Vol.22 No.2

This study was performed to evaluate accuracy and precision of filter method and impinger method for analyzin airborne isocyanates in mixture (2, 6-TDI, HDI, 2, 4-TDI, MDI). Filter method was performed using the OSHA Method 42 and impinger method using the NIOSH Method 5521. The samples were analyzed by high performance liquid chromatography-ultraviolet detector (HPLC-UVD). After the optimum operating conditions for each method were investigated, samples with various concentration levels were quantified at the conditions. The precision was expressed by the pooled coefficient of variation(C.V.) and the accuracy by overall accuracy. The results are summarized as follows: 1. The optimum condition of filter method was determined at 35/65 ACN/buffer (0.01 M ammonium acetate) in mobile phase. And in case of impinger method, it was at 30/70 ACN/buffer(0.2 M sodium acetate). The effect of concentrations of acetate on the separation of the peaks was not significant, but, the effect of ACN/buffer ratio was significant. 2. The correlation coefficients for the two methods were above 0.9 in all isocyanate compounds. Average recovery efficiencies for 2, 6-TDI, HDI, 2, 4-TDI and MDI in filter method were 92.4%, 102.6%, 87.3% and 101.0%, respectively. Those in impinger method were 106.6%, 106.7%, 99.0% and 103.6%, respectively. As a result, the recovery efficiency of impinger method was higher than those of filter method in analyzing isocyanate compounds. 3. The pooled coefficients of variations of the methods were slightly higher than expected. The overall accuracies of the methods were within $\pm 25%$ for each isocyanate compound. Since these results satisfy NIOSH criteria, the accuracy of the experiment is appropriate. 4. As seen above, impinger method is more efficient than filter method. But, there are many disadvantages in impinger method. Therefore, solid sorbent such as a glass fiber filter must be developed in order to have the high efficiency not less than that of impinger method in the future.

Effect of isocyanate crosslinkers blocked with amine derivatives on rheological and crosslinking characteristics of automotive clearcoats

Young-Gun June,정인조,Tae Hee Lee,하미란,Seung Man Noh,정현욱 한국유변학회 2021 Korea-Australia rheology journal Vol.33 No.1

Isocyanate crosslinkers with blocking agents based on various amine derivatives were newly synthesized for automotive clearcoat applications. Amine-based blocking agents were prepared by varying the alkyl substituent attached on both sides of the main nitrogen atom (named DEA, DiPA, NtBEA, and NtBiA) to modify their deblocking feature in blocked isocyanates (BIs) and curing reaction under thermal curing conditions. Curing properties of clearcoats containing amine-based BIs were characterized at the normal curing temperature of 150°C and were compared with those by the commercialized BI, Desmodur® PL350. The dissociation ability of the amine-based BIs was interpreted using the density functional theory (DFT) simulation under their optimized geometric configurations. The urethane reaction between isocyanate group in BIs and hydroxyl group in a hydroxyl-functionalized polyol binder within clearcoats was confirmed from the OH stretching absorbance data via Fourier-transform infrared (FT-IR) spectrometer. The real-time crosslinking dynamics of various clearcoats with amine-based BIs were comprehensively investigated using rotational rheometer and rigid-body pendulum tester. The surface mechanical properties of fully-cured clearcoat films were measured by nano-indentation and nano-scratch testers to address the crosslinked network formation caused by amine-based BIs. It is demonstrated that the amine-based BIs could be favorably applied to thermal curing process of clearcoats, based on their reactivity and curing performance.

Ruthenium(II)-Catalyzed CH/NH Carbonylative Cyclization of 2-Aryl Quinazolinones with Isocyanates as CO Surrogates

Jin Ho Choi,Hak Do Kim,강주영,정태주,ghosh prithwish,In Su Kim 대한화학회 2021 Bulletin of the Korean Chemical Society Vol.42 No.3

The ruthenium(II)-catalyzed C?H carbonylation of 2-aryl quinazolinones with isocyanates as carbonyl sources is described. The developed method provides direct access to biologically relevant isoindoloquinazolinone core through C?H aminocarbonylation followed by intramolecular annulation. A broad range of substrate scope and functional group tolerance were observed. Gram-scale reactions and synthetic transformations demonstrate the synthetic potential of this protocol.

Evaluation of Exposure to Isocyanates Used in Furniture Industry

Lee, Su-Gil,Lee, Nae-Woo,Pisaniello, Dino. L 한국안전학회 2006 한국안전학회지 Vol.21 No.2

크롬과 Toluene Diisocyanate에 의한 직업성 천식

조석 ( Seok Cho ),고영일 ( Young Il Koh ),문장식 ( Jang Sik Mun ),지승규 ( Seung Gyu Ji ),안재숙 ( Jae Sook Ahn ),정종원 ( Jong Won Chung ),최인선 ( In Seon Choi ) 대한천식알레르기학회 2005 천식 및 알레르기 Vol.25 No.3