Phthalic anhydride allergy: development and characterization of optimized hapten-carrier conjugates for improved diagnosis.

BACKGROUND: At present the diagnosis of IgE-mediated hypersensitivity to phthalic anhydride (PA) is based on conjugates that are not characterized or standardized. The aim of this study was to develop optimized and molecularly characterized PA conjugates that can be used to improve the diagnosis of PA-allergy. METHODS: The PA conjugates were synthesized and the number of haptens bound on a carrier protein was estimated by matrix-assisted laser desorption/ionization time of light (MALDI-TOF) mass spectrometry. The ability of conjugates to bind IgE and IgG antibodies was measured by enzyme-linked immunosorbent assay (ELISA). Reactivity of the conjugates in vivo was evaluated by skin prick testing. RESULTS: The most active IgE-binding conjugates had a PA : HSA molar ratio of 80 : 1. In the optimal conjugates the average numbers of PA haptens per carrier molecule of human serum albumin (HSA) were 14-16. In ELISA, all 13 patients and none of the 20 controls had IgE antibodies to optimized PA conjugate. The sensitivity and specificity of the ELISA was comparable to commercial CAP RAST. PA conjugates elicited positive test results in skin prick testing showing that conjugates are immunologically active also in vivo. CONCLUSIONS: These results indicate that optimized and molecularly characterized PA-HSA conjugates can be used both in vitro and in vivo assays to improve the diagnosis of PA allergy.

Extractable latex allergens in airborne glove powder and in cut glove pieces.

BACKGROUND: Quantification of natural rubber latex (NRL) allergens of NRL glove extracts has been reported in several studies. Similarly, immunoassay studies reporting the level of NRL aeroallergens in air samples have been published. When studying the NRL allergens of gloves, however, little attention has been focused on identifying the relationship between extractable NRL allergens of medical gloves and NRL aeroallergens in indoor air. OBJECTIVE: In an experimental study we analysed NRL aeroallergens of medical gloves in joint relation to total airborne dust concentration and NRL allergen concentration in gloves. METHODS: NRL aeroallergen level was measured using a chamber setting with 18 lots of powdered medical gloves. In each setting 10 pairs of powdered NRL gloves were swinging in an unventilated chamber (9 m3). Air samples were collected using airflow through Millipore filters (pore size 0.8 microm). The filters were weighed before and after the experiment, and total airborne dust concentration in the chamber was calculated. The filter samples were then extracted and the NRL allergen level measured by IgE ELISA-inhibition assay. Furthermore, cut NRL gloves were extracted and analysed by the same method. Finally, levels of two major NRL allergens, Hev b1 and Hev b 6.02, were measured in three selected NRL glove brands. RESULTS: The NRL aeroallergen level in the chamber air ranged from < 0.9 to 2.9 allergen units (AU)/m3. The total airborne dust concentration in the chamber air remained low with all lots of gloves measured (range < 20 to 80 microg/m3). The NRL allergen level in cut glove extracts varied over 100-fold (< 10 to 1050 AU/mL). Statistically significant correlation between aeroallergen concentration and airborne dust (r = 0.8, P = 0.0015) concentration was found. Moreover, significant correlation between aeroallergen levels and allergen content of cut glove pieces was observed (r = 0.59, P < 0.05). Hev b 1 levels varied from 9 to 25 ng/mL and the levels of Hev b 6.02 from 1720 to 14460 ng/mL in the glove extracts. In the extracts from airborne dust samples, Hev b 6.02 content varied from 61 to 183 ng/m3, whereas Hev b 1 levels were very low (0.4 to 3 ng/m3). CONCLUSION: An elevated NRL aeroallergen level is rather related to a high level of airborne glove powder than to a high concentration of extractable NRL allergen in medical gloves.

Occupational allergic contact dermatitis from unsaturated polyester resin in a car repair putty.

BACKGROUND: Unsaturated polyester (UP) resins are widely used as cements in car repair painting to produce a smooth surface before the final painting. We report two car painters with hand and face dermatitis who were sensitized to a UP resin used for car repair cements. METHODS: Patch testing with commercial substances and ingredients and extracts from UP resins was used to verify the sensitivity. RESULTS: Both patients showed an allergic patch test reaction to a UP resin. They also had an allergic patch test reaction to diethyleneglycol maleate (DEGM), an extract of a UP resin. CONCLUSIONS: Both patients had been patch tested elsewhere with negative results because UP resins had not been used for patch testing. Accordingly, patients with dermatitis who have been exposed to UP resins need to be patch tested with UP resins. The specific chemical causing allergic contact dermatitis in our patients was DEGM.

Customer exposure to MTBE, TAME, C6 alkyl methyl ethers, and benzene during gasoline refueling.

We studied customer exposure during refueling by collecting air samples from customers' breathing zone. The measurements were carried out during 4 days in summer 1996 at two Finnish self-service gasoline stations with "stage I" vapor recovery systems. The 95-RON (research octane number) gasoline contained approximately 2.7% methyl tert-butyl ether (MTBE), approximately 8.5% tert-amyl methyl ether (TAME), approximately 3.2% C6 alkyl methyl ethers (C6 AMEs), and 0.75% benzene. The individual exposure concentrations showed a wide log-normal distribution, with low exposures being the most frequent. In over 90% of the samples, the concentration of MTBE was higher (range <0.02-51 mg/m3) than that of TAME. The MTBE values were well below the short-term (15 min) threshold limits set for occupational exposure (250-360 mg/m3). At station A, the geometric mean concentrations in individual samples were 3.9 mg/m3 MTBE and 2. 2 mg/m3 TAME. The corresponding values at station B were 2.4 and 1.7 mg/m3, respectively. The average refueling (sampling) time was 63 sec at station A and 74 sec at station B. No statistically significant difference was observed in customer exposures between the two service stations. The overall geometric means (n = 167) for an adjusted 1-min refueling time were 3.3 mg/m3 MTBE and 1.9 mg/m3 TAME. Each day an integrated breathing zone sample was also collected, corresponding to an arithmetic mean of 20-21 refuelings. The overall arithmetic mean concentrations in the integrated samples (n = 8) were 0.90 mg/m3 for benzene and 0.56 mg/m3 for C6 AMEs calculated as a group. Mean MTBE concentrations in ambient air (a stationary point in the middle of the pump island) were 0.16 mg/m3 for station A and 0.07 mg/m3 for station B. The mean ambient concentrations of TAME, C6 AMEs, and benzene were 0.031 mg/m3, approximately 0.005 mg/m3, and approximately 0.01 mg/m3, respectively, at both stations. The mean wind speed was 1.4 m/sec and mean air temperature was 21 degreesC. Of the gasoline refueled during the study, 75% was 95 grade and 25% was 98/99 grade, with an oxygenate (MTBE) content of 12.2%.

Occupational asthma caused by triglycidyl isocyanurate (TGIC).

BACKGROUND: Polyester powder paints are extensively used in metal painting. Triglycidyl isocyanurate (TGIC), an epoxy compound, is often used as a hardener. Several cases of allergic eczema from occupational exposure to TGIC have been reported in the literature. OBJECTIVE: We examined a 36-year-old non-smoking man who worked mainly as a spray painter, using a polyester powder paint containing 4% TGIC. During painting he used protective clothing and a motorized breathing protector. After 4 years he developed eczema on his hands, face and body, and an occupational allergic eczema caused by TGIC was diagnosed. He also suffered from powder-paint-related asthmatic symptoms. METHODS: Occupational asthma was diagnosed in accordance with the accepted guidelines. Inhalation challenge tests were performed with the paint and TGIC. RESULTS: Spirometry showed slight obstruction; the blood eosinophils and serum IgE value were elevated. Skin-prick tests with common environmental allergens were negative. The challenge test with lactose powder was also negative. A challenge test with a paint containing TGIC (4%) induced a dual reaction in PEF and a late 23% fall in FEV1. A test with TGIC (4%) mixed with lactose induced a dual PEF reaction, and also dual changes in spirometry. The PD15 in the histamine challenge test decreased significantly after the challenge tests. CONCLUSIONS: To our knowledge this is the first diagnosed case of occupational asthma caused by TGIC. This case report emphasizes the importance of protecting both the skin and respiratory tract of workers against chemicals such as TGIC, capable of causing skin and respiratory allergy.

Allergic alveolitis following exposure to epoxy polyester powder paint containing low amounts (<1%) of acid anhydrides.

Only one case report concerning allergic alveolitis caused by polyester powder paint has been published previously. The aim of this study was to determine whether phthalic anhydride (PA) or trimellitic anhydride (TMA) is the alveolitis-causing agent in such paint. A 61 year old woman showed recurrent symptoms of chills, cough, and fever whilst at work. She was working in a plant where epoxy polyester powder paints were used to paint metal. The paint was found to contain low (<1%) amounts of TMA and PA. The patient showed shadowing on chest radiographs. In bronchoalveolar lavage, lymphocytosis (67%) and a low T-helper/T-suppressor ratio (0.2) were found. Transfer factor was within normal limits, but a slight reduction was verified after re-exposure to the paint. The symptoms, exposure, reduction in transfer factor, findings on chest radiographs and bronchoalveolar lavage were consistent with allergic alveolitis. In conclusion, the polyester powder paint used in the plant caused allergic alve olitis in this patient. Of the constituents in the paint, trimellitic anhydride and phthalic anhydride were the possible causative agents.

Glycophorin A somatic cell mutation frequencies in Finnish reinforced plastics workers exposed to styrene.

We have used the glycophorin A (GPA) in vivo somatic cell mutation assay to assess the genotoxic potential of styrene exposure in 47 reinforced plastics workers occupationally exposed to styrene and 47 unexposed controls matched for age, gender, and active smoking status. GPA variant erythrocyte frequencies (Vf), reflecting GPA allele loss (phi/N) and allele loss and duplication (N/N) somatic mutations arising in vivo in the erythroid progenitor cells of individuals of GPA M/N heterozygous genotype, were flow cytometrically determined in peripheral blood samples from these subjects. Measurements of styrene exposure of the workers at the time of blood sampling showed a mean 8-h time-weighted average (TWA8-h) styrene concentration of 155 mg/m3 (37 ppm) in the breathing zone. Mean urinary concentrations of the styrene metabolites mandelic acid (MA) and mandelic acid plus phenyl glyoxylic acid (MA+PGA) were 4.4 mmol/liter (after workshift) and 2.1 mmol/liter (next morning), respectively. Multivariate analysis of covariance on log-transformed GPA Vf data with models allowing adjustment for age, gender, smoking status, and styrene exposure showed that N/N Vf were nearly significantly increased among all of the exposed workers (adjusted geometric mean, 6.3 per million versus 5.0 in the controls; P = 0.058) and were statistically significantly elevated (adjusted geometric mean, 6.8 versus 5.0 in the controls; P = 0.036) among workers classified into a high-exposure group according to personal TWA8-h concentration of styrene in the breathing zone of > or = 85 mg/m3 (20 ppm; Finnish threshold limit value). Women in this high exposure group showed especially elevated N/N Vf (adjusted geometric mean 8.5 versus 5.3 in control women; P = 0.020); this elevation was also significant if urinary MA+PGA of > or = 1.2 mmol/liter was used as the basis of classification (adjusted geometric mean, 8.3; P = 0.030). The occupational exposure could not be shown to influence phi/N Vf. Cigarette smoking was associated with significantly elevated GPA Vf among active smokers (P = 0.042 for phi/N and P = 0.020 for N/N) and among active and ex-smokers combined (P = 0.014 for N/N). Its influence on phi/N Vf was especially clear among active smokers in the control group (P = 0.005). An effect of smoking, nearly statistically significant, was also observed for the phi/N Vf of control ex-smokers (P = 0.055) and of all active and ex-smokers combined (P = 0.050). Thus, the two characterized chemical exposures experienced by this group of workers and controls appear to produce differential effects on the two independent classes of GPA variants enumerated in the assay. This result suggests that the genotoxicity of these agents is mediated, at least in part, by different genetic mechanisms. Styrene exposure is associated with a specific increase in GPA N/N Vf; these allele loss and duplication variants reflect predominantly somatic recombination mechanisms in erythroid progenitor cells. Tobacco smoke exposure in active and ex-smokers is also associated not only with an increase in N/N Vf but also with an increase in phi/N Vf, reflecting the induction of GPA gene-inactivating mutations, including point mutations and deletions. This finding is consistent with a broad mechanistic spectrum of tobacco smoke genotoxicity associated with this complex mixture of chemical mutagens. Finally, there was no detectable effect of age on phi/N Vf; however, a highly significant (P = 0.0002) increase in N/N Vf with age, even after adjustment for other variables, was observed.

Gas chromatographic-mass spectrometric determination of chlorophenols in the urine of sawmill workers with past use of chlorophenol-containing anti-stain agents.

The aim of this work was to establish whether workers at sawmills where chlorophenol-containing anti-stain agents had been previously used were still exposed to chlorophenols. A gas chromatographic-mass spectrometric (GC-MS) procedure for the determination of chlorophenols in urine was developed. Chlorophenols were determined from hydrolysed urine as acetylated derivatives and determined by GC-MS using selected ion monitoring (SIM). Isolation of the chlorophenols with toluene gave the best extraction efficiencies (65-119%). Stability tests at -20 degrees C showed no degradation of the chlorophenols studied during 6 months. The limit of quantification was 3.6 ng mg-1 creatinine for 2,4,6-trichlorophenol, 5.5 ng mg-1 for 2,3,4,6-tetrachlorophenol and 3.6 ng mg-1 for pentachlorophenol. Traces of 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol and pentachlorophenol were found both in previously exposed workers and in non-exposed controls, the urinary concentrations ranging from 1.1 to 15.9 ng mg-1 creatinine. The concentrations of urinary chlorophenols in previously exposed workers were of the same magnitude as those found in non-exposed controls and in the general population. The results show that it is unlikely that sawmill workers would be currently occupationally exposed to chlorophenols or polychlorinated dibenzo-p-dioxins and dibenzofurans via a contaminated work environment.

Immunologic contact urticaria due to airborne methylhexahydrophthalic and methyltetrahydrophthalic anhydrides.

Acid anhydrides are low-molecular-weight chemicals known to cause respiratory irritancy and allergy. Skin allergy has on rare occasions been reported. 2 workers contracted hives and itching on uncovered skin after 2 months exposure to methyltetrahydrophthalic anhydride (MTHPA) and methylhexahydrophthalic anhydride (MHHPA), to which they had airborne exposure. Later, the patients also developed conjunctivitis, rhinitis, sore throat, cough or asthma. In addition to MTHPA, 1 worker was also exposed to unsaturated polyester resin (UP). Both patients' immediate allergy to MTHPA and MHHPA was verified by positive prick tests to MTHPA and MHHPA, conjugated with human serum albumin (HSA), and positive radioallergosorbent tests (RASTs) to these anhydrides. On prick testing, both patients also reacted to a phthalic anhydride (PA)-HSA-conjugate and 1 of the patients to UP-HSA-conjugate. Specific immediate allergy to UP was shown by RAST. RAST inhibition with MTHPA, MHHPA and UP-resin conjugates confirmed IgE-mediated allergy and cross-reactivity between anhydrides. Our patients had developed airborne contact urticaria caused by phthalic anhydrides, in addition to respiratory allergy. Phthalic anhydride contained in the UP resin was possibly responsible for the immediate reaction of the skin.

Structure of octreotide, a somatostatin analogue.

Octreotide, a synthetic somatostatin analogue, is an octapeptide with one disulfide bridge. Crystals of octreotide are orthorhombic, space group P2(1)2(1)2(1), a = 18.458 (5), b = 30.009 (7), c = 39.705 (27) A, with three molecules of octapeptide, one ordered oxalate dianion and 52 water molecules in the asymmetric unit. Complete protonation of the NH(2) groups (as assumed in the refinement) would require three oxalate dianions in the asymmetric unit for charge neutrality; a chemical analysis indicated that four are present. In either case they are so disordered that they cannot be distinguished from the water molecules. The 18 951 unique reflections (R(sym) = 0.026) used for structure solution and refinement were recorded with the EMBL imaging-plate scanner using synchrotron radiation. The structure was solved by Patterson interpretation, locating the three disulfide bridges, followed by tangent phase expansion and E-Fourier recycling. The anisotropic refinement against all F(2) data between 1.04 and 10.0 A resolution by blocked restrained full-matrix least-squares techniques converged to a conventional R index based on F of 0.084 [I > 2a(I) and 10.0 > d > 1.04 A] and wR2, the weighted R-index on F(2), of 0.246 (for all data). One peptide molecule adopts a flat beta-sheet structure; the other two possess different irregular backbone conformations, but are similar to each other. All three molecules have a distorted type II' beta-turn around the D-Trp-Lys region, but exhibit different side-chain conformations. The crystal structure is stabilized by a network of inter- and intramolecular hydrogen bonds.

Exposure, skin protection and occupational skin diseases in the glass-fibre-reinforced plastics industry.

A total of 100 workers, 86 from the glass-fibre-reinforced plastics (GRP) industry, 11 from polystyrene production and 3 from polyester resin coating manufacture, were examined for occupational skin hazards and for evaluation of skin protection. The workers had been exposed to many chemicals. Those working in the GRP industry had also been exposed to glass fibre and to dust produced by finishing work. 94% used protective gloves. 22 workers, all employed in the GRP industry, had contracted occupational skin disorders. 6 had allergic and 12 irritant contact dermatitis. 4 workers had an accidental injury caused by a peroxide catalyst, fire, hot air and constant mechanical friction. Allergic dermatoses were due to natural rubber (latex) (4 cases) in protective gloves, phenol-formaldehyde resin (1 case) and cobalt naphthenate (1 case). Irritant hand dermatoses (5 cases) were caused by the combined hazardous effect of unsaturated polyester or vinyl ester resins, organic solvents, glass fibre and dust from finishing work on the skin. Other cases of irritant dermatoses (7 cases) were due to the dust, promoted by mechanical friction of clothes. Skin disorders in the GRP industry were common (26%) but the symptoms were mild and only 3 patients had been on sick leave because of occupational skin disease.

Nervous system effects of occupational exposure to styrene: a clinical and neurophysiological study.

Quantitative EEG of 99 workers occupationally exposed to styrene was analyzed and compared to exposure parameters. All of the workers came from reinforced plastics industry. The workplaces and factories were previously evaluated, and the exposure levels were known rather accurately. The exposure information form workplaces and the individual exposure data were combined to form an Exposure Index, which reliably reflected long-term exposure to styrene in various occupational settings. All of the subjects underwent careful medical, neurological, and neurophysiological examinations. Quantitative EEG was recorded from 19 channels and analyzed for absolute and relative power, asymmetry, coherence, frequency distribution, and statistical normative database comparisons (Neurometrics). The EEG data showed a significant increase of abnormal EEG classifications in workers with higher exposure. When the workers were divided into two groups, based on the exposure data, those with higher exposure had higher absolute EEG power in alpha and beta bands in the frontotemporal regions of the brain. The findings indicate that abnormalities in cerebral function can be demonstrated even with relatively low mean exposure levels. It is concluded that the efforts to lower the administrative hygienic levels of styrene have been in the right direction.

The occupational scene of styrene.

Styrene readily undergoes homopolymerization as well as copolymerization with other monomers, such as acrylonitrile and butadiene. In closed polymerization processes, exposure of workers to styrene is generally lower than current reference values (20-50 ppm), but high peaks of exposure may occur during the cleaning, filling and maintenance of reaction vessels and during transport of liquid styrene. Styrene is used not only in styrene polymers but also as a reactive solvent in the manufacture of unsaturated polyester resins. During the lamination process, when resins are applied manually or by spraying in open moulds, workers are exposed to styrene at concentrations that are on average two or three times higher than the 8-h time-weighted average hygienic standard, 20 ppm. Further, exposures during the open mould process tend to fluctuate widely, so that short-term exposures are often twice the short-term reference value (100 ppm; 15-min time-weighted average). These processes also involve exposure to styrene oxide, which is a suspected carcinogen. Use of low-emission resins reduces exposure during curing but not during lamination itself. The exposure of laminators can be reduced by use of combined, carefully planned, general and local ventilation, adequately designed work places and promotion of safe working habits. The best way of controlling exposures to styrene in the reinforced plastic industry in general would be to automate the processes and to use closed moulds.

Neurotoxicity in workers exposed to styrene.

Quantitative electroencephalography (EEG) for 99 workers exposed to styrene in the reinforced-plastics industry was analysed and compared with exposure parameters. The work places and factories from which the subjects were selected had been evaluated previously, and exposure levels were known relatively accurately. That information and data on individual exposures were combined to create an exposure index, which reliably reflected long-term exposure to styrene in various occupational settings. All of the subjects underwent careful medical and neurophysiological examinations. Quantitative EEG was recorded on 19 channels and analysed for absolute and relative power, asymmetry, coherence, frequency distribution, and statistical normative data base comparisons (neurometrics). When the workers were divided into three groups on the basis of exposure, workers with the highest exposure had significantly more EEGs classified as abnormal and had higher absolute EEG power in alpha band in the fronto-temporal regions of the brain. The findings indicate that abnormalities can occur in cerebral function even after relatively low mean exposures. We conclude that the efforts to lower regulatory hygienic levels of styrene are justified.

Determination of 4-methyl-cis-hexahydrophthalic anhydride in human blood by gas chromatography with electron-capture detection.

A gas-chromatographic technique using 63Ni electron-capture detection was applied to the determination of 4-methyl-cis-hexahydrophthalic anhydride in the blood of workers occupationally exposed to this airborne agent. The detection limit was 0.24 nmol ml-1. For occupational exposure to between 0.14 and 0.31 mg m-3 of the anhydride, the anhydride concentration in the workers' blood samples ranged from 3.4 to 10.7 nmol ml-1. The results are consistent with earlier findings in animal exposure experiments and support the view that the hydrolysis of the anhydride in a biological medium is not spontaneous, but might be an enzyme-catalysed reaction. The resulting dicarboxylic acid is excreted by the kidneys without further conjugation reactions.

Styrene revisited--exposure assessment and risk estimation in reinforced plastics industry.

A survey performed in 32 workshops in reinforced plastics industry showed the mean TWA 8 h concentration of styrene in personal air to be 43 ppm (range 5-182 ppm) among laminators and 11 ppm (range 1-133 ppm) among other workers. The biological measurement of urinary mandelic acid + phenylglyoxylic acid showed mean values of 2.4 mmol/l among laminators without respirators and 1.3 mmol/l when respirators were used. No effects of work related exposure were detected in the cytogenetic parameters, chromosome aberrations, sister chromatid exchanges or micronuclei analyzed in peripheral blood lymphocytes. Grading of the exposure on the basis of lamination method, years of exposure, daily laminating time, air styrene concentration and urinary mandelic acid among laminators, neither revealed any dose dependency.