Association between positive patch tests to epoxy resin and fragrance mix I ingredients.

BACKGROUND: Both epoxy resin (diglycidyl ether of bisphenol A) and fragrance mix I are included in the European baseline series of contact allergens. A significant association between positive reactions to epoxy resin and fragrance mix has been reported by others. OBJECTIVE: To investigate and possibly reproduce this association with the use of TRUE((R)) test data and supplementary tests with fragrance mix ingredients from the Department of Dermatology, Odense University Hospital. MATERIALS AND METHODS: Six thousand one hundred and fifteen consecutive eczema patients tested from 1995 to 2007 were included, and test results from all patients tested with fragrance mix ingredients were analysed. RESULTS: One hundred and forty-five (2.4%) were positive to epoxy resin and 282 (4.6%) were positive to fragrance mix I. Nineteen were positive to both giving an odds ratio of 3.3, which is significant (95% CI 2.0-5.4). Analysis of association to individual fragrance mix ingredients showed a significant association to alpha-amyl cinnamal and isoeugenol. CONCLUSIONS: The significant association between positive reactions to epoxy resin and fragrance mix I was reproduced. However, the clinical implications are not clarified, and even though the association may be coincidental, the fact that it can be reproduced with a different patch test system and in a different population speaks against a random result. Further studies may help to interpret the association.

Local lymph node assay (LLNA): comparison of different protocols by testing skin-sensitizing epoxy resin system components.

Thirteen epoxy resin system components were tested in the LLNA with regard to their sensitizing potency. Lymph node stimulation was quantified not only by measuring the incorporation of [3H]-thymidine into the ear lymph nodes but also the counts of cells recovered from these organs. Equivalent figures were obtained with both endpoints used for the evaluation of lymph node cell proliferation if the reference stimulation indices were adjusted. When dissolved in acetone, all test substances showed skin-sensitizing potential, mainly on the boundary between "strong" and "moderate" according to common potency evaluation schemes. Replacing acetone with acetone/olive oil (4:1) as a vehicle for four selected test items, resulted in considerably lower estimated concentrations for sensitization induction. The challenges in comparing the results obtained by different LLNA variations are discussed.

A review of 241 subjects who were patch tested twice: could fragrance mix I cause active sensitization?

BACKGROUND: Active patch test sensitization is an uncommon phenomenon which may have undesirable consequences for those undergoing this gold-standard investigation for contact allergy. OBJECTIVES: To perform a retrospective analysis of the results of 241 subjects who were patch tested twice in a monocentre evaluating approximately 1500 subjects per year. METHODS: Positivity to 11 common allergens in the recommended Baseline Series of contact allergens (European) was analysed: nickel sulphate; Myroxylon pereirae; fragrance mix I; para-phenylenediamine; colophonium; epoxy resin; neomycin; quaternium-15; thiuram mix; sesquiterpene lactone mix; and para-tert-butylphenol resin. RESULTS: Only fragrance mix I gave a statistically significant, increased rate of positivity on the second reading compared with the first (P=0.011). This trend was maintained when separately analysing a subgroup of 42 subjects who had been repeat patch tested within 1 year; this analysis was done to minimize the potential confounding factor of increased usage of fragrances with a wide interval between both tests. To reduce the confounding effect of age on our data, we calculated expected frequencies of positivity to fragrance mix I based on previously published data from our centre. This showed a marked excess of observed cases over predicted ones, particularly in women in the age range 40-60 years. CONCLUSIONS: We suspect that active sensitization to fragrance mix I may occur. Similar published analysis from another large group using standard methodology supports our data.

Metabolism and disposition of n-butyl glycidyl ether in F344 rats and B6C3F1 mice.

The disposition of [(14)C]-labeled n-butyl glycidyl ether (BGE, 3-butoxy-1,2-epoxypropane) was studied in rats and mice. The majority of a single p.o. dose (2-200 mg/kg) was excreted in urine (rats, 84-92%; mice, 64-73%) within 24 h. The rest of the dose was excreted in feces (rats, 2.6-7.7%; mice, 5.3-12%) and in expired air as (14)CO(2) (rats, 1.5%; mice, 10-18%), or remained in the tissues (rats, 2.7-4.4%; mice, 1.5-1.7%). No parent BGE was detected in rat or mouse urine. Fifteen urinary metabolites were identified, including 3-butoxy-2-hydroxy-1-propanol and its monosulfate or monoglucuronide conjugates, 3-butoxy-2-hydroxypropionic acid, O-butyl-N-acetylserine, butoxyacetic acid, 2-butoxyethanol, and 3-butoxy-1-(N-acetylcystein-S-yl)-2-propanol, the mercapturic acid metabolite derived from conjugation of glutathione (GSH) with BGE at the C-1 position. Some of these metabolites underwent further omega-1 oxidation to form a 3'-hydroxybutoxy substitution. One urinary metabolite was from omega-oxidation of 3-butoxy-1-(N-acetylcystein-S-yl)-2-propanol to yield the corresponding carboxylic acid. Oxidative deamination of 3-butoxy-1-(cystein-S-yl)-2-propanol gave the corresponding alpha-keto acid and alpha-hydroxy acid metabolites that were present in mouse urine but not in rat urine. An in vitro incubation of BGE with GSH showed that the conjugation occurred only at the C-1 position with or without the addition of GSH S-transferase.

Thoracic radicular vessels by simultaneous intra-arterial and intravenous injection of araldite.

Spinal dural arteriovenous fistulas (SDAVF) consist of a shunt between a radicular artery and a radicular vein, resulting in a progressive paraparesis. They are most prevalent in middle-aged men (male to female ratio 5 to 1). It is unknown why the shunt develops. It is possible that there are anatomical differences between men and women, which may account for the sex difference in prevalence. We performed a study with simultaneous arterial and venous araldite injection in 5 male and 5 female human cadavers using different colors. The mean age of the human cadavers was 78 years (range 70-91). The human cadavers were not known to have suffered from spinal disease. We did not find significant differences in thoracic vasculature between men and women. Two different types of radicular arteries could be identified: The first was the arterial feeder of the root ganglion or the dura mater, which is also called the distal radicular artery. The second was the tributary of the anterior spinal artery, which is also called the medullary artery. We found three arteriovenous anastomoses between the radicular artery and the corresponding vein, and three between the radicular artery and venous plexus. We found a total of six thoracic arteriovenous shunts in four cadavers but their role in the pathogenesis of SDAVF remains uncertain. No vascular anatomic differences between men and women were found.

Epoxy-resin injection of the cerebral arterial microvasculature: An evaluation of the limits of spatial resolution in 8 Tesla MRI.

The purpose of this study was to quantify the spatial resolution of microscopic arteries on magnetic resonance images acquired at 8 Tesla (T). Techniques similar to those used for standard MRI of the human brain in vivo at 8 T were utilized to generate high-resolution gradient echo (GE) images of a whole postmortem human brain whose common carotid arterial system had been injected with an epoxy-resin. Single slice images, along with summed images of up to 5 contiguous slices, were then compared to color digital photographs detailing the distribution of the arterial system on the surface of the same injected brain. There was excellent MR visualization of the microscopic cerebral arteries down to a spatial resolution of 200 microm. Through the use of an 8 T whole-body MRI scanner and standard GE imaging sequences, microscopic arterial structures can be clearly resolved down to a dimension of 200 microm.

Comportamento dimensional de resina epóxica industrial carregada com diatomita para ser empregada na modelagem odontológica / Dimensional behavior of industrial epoxy resin loaded with diatomite used for dental modeling

A proposta desse estudo foi avaliar o comportamento dimensional de uma resina epóxica industrial carregada com diatomita para ser empregada na modelagem odontológica. Modificou-se a resina epóxica Epoxiglass 1504 e o seu endurecedor (Epoxiglass Ind. e Com. de Produtos Químicos Ltda., Diadema-Brasil) com adição de 30 por cento em peso de diatomita pura e silanizada com Silano Siquest A187 (Crompton S/A, Itatiba-Brasil). Empregou-se matriz com marcações no sentido vertical distantes em 4.000µm e no sentido horizontal em 1.328µm. Os modelos produzidos em resina epóxica pura, modificada com diatomita, modificada com diatomita silanizada foram analisados em microscópio Nikon (Japão). Os resultados foram comparados a obtidos com modelos em Gesso tipo IV Duone micro granulado, (Dentsply-USA); Gesso tipo IV, Fuji Rock EP, (GC América Inc-USA); Gesso tipo IV Resinado, Rock Plus, (Polidental-Brasil); Gesso pedra tipo V...

In vitro evaluation of the antimicrobial activity of five root canal sealers.

The aim of the present study was to analyze the antimicrobial properties of five endodontic sealers: Endo Fill, Endomethasone, Endomethasone N, Sealer 26 and AH-Plus, against the following microorganisms: Candida albicans, Staphylococcus aureus, Enterococcus faecalis, Streptococcus sanguis and Actinomyces naeslundii. The sealers were tested immediately, 24 h, 48 h and 7 days after manipulation.The direct contact method through the observation of the microbial growth in liquid medium and the agar diffusion test were used to evaluate the antimicrobial properties of the sealers. The results, in both methodologies used, showed that immediately after manipulation, Endo-Fill and Endomethasone demonstrated the highest antimicrobial activity, with no statistically significant difference between them. Sealer 26 demonstrated the lowest antimicrobial activity. At all other times after manipulation, there were no statistically significant differences among all the sealers tested. In conclusion, none of the sealers totally inhibited the growth of the microorganisms. Furthermore, the antimicrobial activity of each sealer decreased with time and was dependent upon the microbial susceptibility to them.

Examination of cytotoxicity and mutagenicity of AH26 and AH Plus sealers.

AIM: To study in vitro the cytotoxic and mutagenic effects of AH26 and AH Plus. METHODOLOGY: Cytotoxic effects on Chinese hamster V79 cells were determined by counting viable cells following incubation with eluations of AH26 and AH Plus. In one set of experiments, the materials were mixed, set for 1 h and then eluted with dimethyl sulphoxide (DMSO) for 1 h, 24 h and 7 days. In the other set, AH26 and AH Plus were mixed and set for 1 h, 24 h and 7 days in physiological saline then crushed and eluted in DMSO for 24 h. The cytotoxic effects of these eluates were evaluated. Three concentrations were chosen to examine the mutagenic effects of AH26 and AH Plus: 5.57, 16.7 and 55.7 microg mL(-1). The structural chromosomal aberration analysis and micronucleus test were performed on human lymphocytes according to standard procedures. RESULTS: Dose-response curves of cell survival were obtained. Both materials were shown to be cytotoxic in doses larger than 55.7 microg mL(-1), except for AH26, after 7 days setting time. AH Plus was also shown to be toxic in concentrations of 16.7 microg mL(-1), except after 7 days setting time. Neither AH26 nor AH Plus induced a significant increase of chromosomal aberrations or micronuclei induction at any setting time or concentration. CONCLUSION: There was no mutagenicity found for AH26 and AH Plus on human lymphocytes in highly controlled conditions in vitro.

Apical microleakage of radiolabeled lysozyme over time in three techniques of root canal obturation.

The three methods of obturation assessed in this study were lateral condensation (80 teeth), Thermafil (40 teeth), and McSpadden (40 teeth). All teeth were prepared to the master apical file 30 and widened coronally by Gates Glidden burs before being randomly assigned to experimental groups to be filled by each technique; they were then sealed with nail polish, except for the apical 1 mm. Quantitative evaluation of apical microleakage for each technique was obtained after periods of 1 day, 7 days, 14 days, and 28 days of immersion in a lysozyme solution labeled with radioactive iodine by preparing horizontal sections of the teeth and measuring the level of radioactivity in each section using a gamma counter. Initial (1-day) leakage was least in the Thermafil group and was significantly different from the other techniques. Leakage was greatest in the laterally condensed samples. By the end of the study (28th day) values for lateral condensation were lowest, but were significantly different only for the McSpadden group. For all techniques leakage was most significant in the first 3 mm from the apex and was very low below this level so that all methods can be considered as giving a hermetic seal below 3 mm.

Binding of the potent allergen hexahydrophthalic anhydride in the mucosa of the upper respiratory and alimentary tract following single inhalation exposures in guinea pigs and rats.

Hexahydrophthalic anhydride (HHPA; CAS No. 13149-00-3) is a highly allergenic compound commonly used in the chemical industry. Guinea pigs and rats were exposed to [3H2]HHPA by inhalation for 3-8 h and were killed at various intervals during 7 days. The tissue distribution of non-volatile and covalently bound radioactivity was studied by autoradiography. Tissue bound radioactivity was mainly found in the mucosa of the upper respiratory airways, whereas negligible levels were observed in the lungs. In addition, tissue bound radioactivity was present in the gastrointestinal tract and conjunctiva. Moreover, in the cortex of the kidneys in rats, but not in guinea pigs, a low level of tissue bound radioactivity was found. The radioactivity in the tissues persisted for at least 7 days after the end of exposure. Plasma proteins and soluble proteins from trachea, lung, and kidney from [3H2]HHPA-exposed animals were separated by gel filtration. The radioactivity in dialysed plasma was mainly found in the same fractions as albumin. The soluble proteins from trachea, lung, and kidney in both rats and guinea pigs showed a similar pattern as found in blood. The radioactivity in dialysed plasma from both guinea pigs and rats seemed to decay according to a two-compartment model. The non-extractable binding of [3H2]HHPA in the upper respiratory airways and conjunctiva may be of relevance for symptoms in workers with allergy, since they mainly develop symptoms and signs from the nose and eyes.

Relationship between IgG1 levels and airway responses in guinea pigs actively and passively sensitized to hexahydrophthalic anhydride.

Organic acid anhydrides (OAAs) are industrial chemicals that may cause induction of specific IgE and airway symptoms in exposed workers. They are a good model for studies of relationships between chemical structure and the sensitizing potential of reactive low-molecular-weight compounds. Hexahydrophthalic anhydride (HHPA) is such a compound. This study aimed to evaluate the relationship between specific IgG1 levels and airway responses in a model to predict the sensitizing potential of OAAs. Guinea pigs were either actively or passively sensitized to HHPA. For active sensitization, guinea pigs were injected i.d. with 0.1 ml of olive oil (vehicle) or 0.05, 0.5, or 5% HHPA in olive oil. Passive sensitization was performed by i.p. injection of different volumes of antisera (0.75-6 ml, either unheated to keep IgE or heated to destroy IgE) taken from HHPA-sensitized guinea pigs. Specific antibody levels were evaluated with ELISA and passive cutaneous anaphylaxis. Animals were challenged 16-18 days after active sensitization, or 2 days after passive sensitization, by intratracheal instillation with HHPA conjugated to guinea pig serum albumin (HHPA-GPSA; 0.05% in saline), and the immediate effects on lung resistance (RL), and plasma extravasation, measured as Evans blue dye extravasation, for up to 6 min were recorded. Active sensitization caused production of specific IgG1. Provocation with HHPA-GPSA caused an increase of both RL and Evans blue dye extravasation, which was dependent upon the active sensitization dose. Challenge with HHPA-GPSA in passively sensitized guinea pigs also produced an increase in both RL and Evans blue dye extravasation which was related to the IgG1 level. In the guinea pig model of HHPA-induced airway allergy, the airway responses are closely related to the serum levels of specific IgG1. Thus, the IgG1 levels induced by the immunization may reflect the sensitizing potential of HHPA.

Injection technique and scanning electron microscopic study of the arterial pattern of the 20 gestation days (G20) rat fetus.

A technique to obtain microvascular corrosion casts of the G20 rat fetus and the normal pattern of the main arteries of the G20 rat fetus are described. The casts were studied by means of scanning electron microscopy (SEM). The arterial pattern is similar to that described in the adult; however, several variations have been found. It is concluded that the use of vascular corrosion casts studied by SEM may be particularly helpful to observe the extremely small arteries of rat fetuses. Moreover, we suggest that this technique may be useful in practical teratological studies.

[The embryotoxic and teratogenic action of some brands of epoxy resins]. / Ob émbriotoksicheskom i teratogennom deistvii nekotorykh marok époksidnykh smol.

The studies made permit stating that such epoxy resins as DE-500 with dose levels of 1/10 and 1/50 DL50, DE-1000 with 1/10, 1/50, 1/100, 1/250 DL50, UP-650, UP-650T with 1/10 DL50 administered into the stomach of pregnant females of nondescript albino rats from the 1st to the 19th day of pregnancy (DL50 being 5338 +/- 1134, 6644 +/- 1114, 9180 +/- 1154, 7717 +/- 586, 6980 +/- 621 mg/kg for the resins DE-500, DE-1000, DE-2000, UP-650, UP-650T respectively) have embryotoxic as well as teratogenic effects. The embryotoxic effect of the above epoxy resins depends on the dose administered and their chemical structure. These same embryotoxic and teratogenic effects a need to be taken into consideration in scientific substantiation/revision of hygienic regulations for polyoxipropilene diepoxides and alicyclic epoxy resins.

Anaphylactic bronchoconstriction in immunized guinea pigs provoked by inhalation and intravenous administration of hexahydrophthalic anhydride and methyltetrahydrophthalic anhydride.

We established a guinea-pig model of anaphylactic bronchoconstriction provoked in immunized animals by inhalation and intravenous administration of 4,4-methyltetrahydrophthalic anhydride (MTHPA) and hexahydrophthalic anhydride (HHPA). Guinea pigs were immunized intradermally with either MTHPA (n = 8) or HHPA (n = 8) suspended in olive oil. Control animals (n = 8) were injected with olive oil alone. After 4 weeks, the animals were challenged during mechanical ventilation by inhalation or intravenous administration of MTHPA or HHPA conjugated with guinea-pig serum albumin (GPSA). Airway flow, and airway and esophageal pressures were measured. Resistance (R) and static compliance (Cst) of the respiratory system (rs), lung (1), and chest wall were studied with the flow-interruption technique. After challenge with MTHPA-GPSA or HHPA-GPSA, R,rs and R,1 increased dramatically while Cst,rs and Cst,1 decreased, and severe arterial hypoxia developed. The reaction occurred at a well-defined dose of anhydride and lasted about 30 min. When the same dose was repeated after 30 min, the response was much attenuated. MTHPA and HHPA can induce asthma in guinea pigs. The dose-response curve at antigen challenge is steep. Once a threshold dose is reached, a severe reaction occurs. The reactivity is then exhausted. This model may be suitable for assessing occupational asthma caused by acid anhydrides and possibly by other low-molecular-weight chemicals.

[The cytogenetic activity of some brands of epoxy resins]. / O tsitogeneticheskoi aktivnosti nekotorykh marok époksidnykh smol.

The studies have allow us to ascertain that some epoxy resins, such as DE-500, DE-1000, DE-2000, UP-650, UP-650T, under gastric administration at the dose levels of 1/10 and 1/50 DL50 (DL50 = 5338 +/- 1134, 6644 +/- 1114, 9180 +/- 1154, 7717 +/- 586, 6980 +/- 621 mg/kg for DE-500, DE-1000, DE-2000, UP-650, UP-650T respectively) and ED-22F under inhalational exposure at 1 mg/m3 as per epichlorhydrine over three to four months, have a striking effect on the chromosomal apparatus of the laboratory animals bone marrow cells, bringing about chromosomal structural aberrations. The cytogenetic activity was found to be dependent upon the dose employed as well as duration of the exposure and chemical structure of the epoxy resins.

Carbon fibre composite bone plates. Development, evaluation and early clinical experience.

We compared the mechanical properties of carbon fibre composite bone plates with those of stainless steel and titanium. The composite plates have less stiffness with good fatigue properties. Tissue culture and small animal implantation confirmed the biocompatibility of the material. We also present a preliminary report on the use of the carbon fibre composite plates in 40 forearm fractures. All fractures united, 67% of them showing radiological remodelling within six months. There were no refractures or mechanical failures, but five fractures showed an unexpected reaction; this is discussed.

Sensitization capacity of epoxy resin oligomers in the guinea pig.

Low molecular weight oligomers of an epoxy resin of bisphenol A diglycidyl ether type were isolated by gel permeation chromatography. The sensitizing capacity of these oligomers was assessed with the "guinea pig maximization test". The oligomer with the molecular weight of 340 sensitized 80% to 100% of the animals, but produced no cross reactions to the other oligomers. The MW 624 oligomer sensitized 56-60% of the animals and 30% of these showed cross reactions to the MW 340 oligomer. The MW 908 and MW 1192 oligomers elicited no reactions. It was shown that sensitization with epoxy resin mixtures of high average molecular weight depends mainly on the content of the MW 340 oligomer.