Formaldehyde-negative allergic contact dermatitis from melamine-formaldehyde resin

Melamine-formaldehyde resin (MFR) is used as a textile finish, in tableware, in surface coatings, and in glues in the furniture and wood industry. MFR is considered to be an infrequent sensitizer. Contact allergy to MFR is often combined with formaldehyde allergy. Patients allergic to textile finish often react to MFR, although other finishes are nowadays more commonly used. Besides allergy to textile finish, allergic contact dermatitis from MFR has been described in workers in composite production and in an orthopaedic plaster technician. To our knowledge, there are no previous reports of contact allergy in the plywood industry from MFR. We describe 3 cases of occupational allergic contact dermatitis from MFR without contact allergy to formaldehyde, 1 in the plywood industry, 1 in the production of melamine-laminated chipboard and 1 in laboratory work.

Lymphomatoid contact dermatitis to para-tertyl-butyl phenol resin

Lymphomatoid contact dermatitis refers to the relatively little known phenomenon of allergic contact dermatitis producing histological features suggestive of cutaneous T-cell lymphoma. We report the first case of lymphomatoid contact dermatitis in response to para-tertyl-butyl phenol resin.

Sensitizing capacity of two monomeric aldehyde components in p-tert-butylphenol-formaldehyde resin

Contact allergy to p-tert-butylphenol-formaldehyde resin is not rare. This resin consists of a large number of substances, most of which are unknown. For diagnostic and preventive reasons, the chemical identity of the sensitizers should be known as well as their sensitizing capacities, cross-reaction patterns and presence in the environment. The aim of this study was to investigate the sensitizing capacities and cross-reaction patterns for 5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzaldehyde and 5-tert-butyl-2-hydroxy-benzaldehyde in the guinea pig maximization test. 2,6-Dimethylol p-tert-butylphenol, p-tert-butylcate chol, 2-methylol p-tert-butylphenol, p-tert-butylphenol, 4-tert-butyl-2-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl)-6-hydroxymethyl-phenol and 4-tert-butyl-2-(5-tert-butyl-2-hydroxy-benzyloxymethyl)-phenol were used as potential cross-reacting substances. 5-tert-Butyl-2-hydroxy-3-hydroxymethyl-benzaldehyde was shown to be a sensitizer (p = 0.041). In animals induced with this compound no cross-reactions to the putative cross-reacting substances were seen. In contrast, 5-tert-butyl-2-hydroxy-benzaldehyde failed to induce sensitization and no cross-reactions were detected.

Contact dermatitis from electrocardiograph-monitoring electrodes: role of p-tert-butylphenol-formaldehyde resin

Three cases of allergic contact dermatitis localized to the sites of electrocardiograph-monitoring electrodes are reported. All patients had positive patch tests to both the gel and the adhesive part of the Red Dot 2239 3M monitoring electrode used and to the p-tert-butylphenol-formaldehyde resin (PTBP-F-R) of the standard series. Two patients had a history of possible exposition to the resin previously but there was no explanation for the third. No information about the presence of PTBP-F-R in the electrodes could be obtained from the manufacturers. Chemical analysis of samples of the electrode, using a gas chromatography-mass spectrometry (GC-MS) and high pressure liquid chromatography (HPLC) analytical system, demonstrated the presence of several PTBP-F-R derivatives in both the gel and the adhesive part.

Influence of hyperbranched multi-methacrylates for dental neat resins on proliferation of human gingival fibroblasts

We have previously shown that hyperbranched multi-methacrylate (H-MMA)-modified dental resins have VLC activities, lower polymerization shrinkage, and improved mechanical properties, compared to the 2,2-bis[4-(2-hydroxy-3-methacryloyolxypropoxy)phenyl]propane/triethyleneglycol dimethacrylate (BisGMA/TEGDMA) neat resin. The results are due to the unique molecular structure and high molecular weight of H-MMA intermediates. The purpose of this study was to evaluate the biocompatibility of H-MMA-modified dental neat resins. The cell proliferation of three human gingival fibroblast strains on either H-MMA, BisGMA/TEGDMA, or a polystyrene disk was examined. Following 10 days of cell proliferation, there was no statistical difference in cell number between H-MMA-modified and unmodified resin disks. H-MMA-modified resins had less free monomer leaching than the unmodified resin but showed similar properties in water sorption and contact angle values. All these results suggest that the biocompatibility of H-MMA-modified dental neat resins is as good as that of commercially used BisGMA/TEGDMA resin and H-MMA has potential applications in dental composites.

Low-molecular-weight contact allergens in p-tert-butylphenol-formaldehyde resin

BACKGROUND

p-tert-Butylphenol-formaldehyde resin (PTBPFR) is a contact allergen that is included in most standard patch test series. This resin consists of a large number of substances most of which are unknown.

OBJECTIVE

The aim of this study was to investigate if allergens in PTBPFR are molecules mainly of low (MW < 250), medium, or high molecular weight (MW > 1,000); to isolate and identify some of the low molecular weight components of the resin; and for new substances to determine if these were allergens.

METHODS

Gel permeation chromatography, patch testing, high-pressure liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectrometry were used.

RESULTS

Patch test reactions indicated allergens in low-, medium-, and high-molecular-weights fractions. The strongest patch test reactivity was seen to a medium molecular weight fraction constituting only 6% wt/wt of the resin for 4 of the patients. Two patients reacted positively to low molecular weight fractions, and one of these patients reacted only to these fractions. The following substances were isolated: 4-tert-butyl-[1,2]benzoquinone, 4-tert-butyl-2,6-bis-hydroxymethyl-phenol, 4-tert-butylbenzene-1,2-diol, 4-tert-butyl-2-hydroxymethyl-phenol, 5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzaldehyde, 4-tert-butyl-2-hydroxymethyl-6-methoxymethyl-phenol, and p-tert-butylphenol. Patients reacted positively to 5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzaldehyde and 4-tert-butyl-2-hydroxymethyl-6-methoxymethyl-phenol but not to 4-tert-butyl-[1,2]benzoquinone.

CONCLUSION

Two new allergens in PTBPFR were found: 5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzaldehyde and 4-tert-butyl-2-hydroxymethyl-6-methoxymethyl-phenol.

Contact allergy to the monomers in p-tert-butylphenol-formaldehyde resin

In many adhesive formulations p-tert-butylphenol-formaldehyde resin (PTBP-F-R) is used as a binder. Contact allergy to this resin is not rare. In patients hypersensitive to PTBP-F-R, and butylphenol derivatives therein, it is for diagnostic and preventive reasons necessary to know the nature of the primary sensitizing substances, as well as the cross-reaction patterns for these. The aim of this study was to investigate contact allergy to monomers in PTBP-F-R and potential cross-reacting substances. 12 patients hypersensitive to PTBP-F-R were patch tested with 2 monomers, the raw materials formaldehyde and p-tert-butylphenol, and 3 closely related substances. High pressure liquid chromatography (HPLC) was used to investigate the purity of the test substances. It was shown that the monomers 2-methylol p-tert-butylphenol and 2,6-dimethylol p-tert-butylphenol could elicit allergic reactions in humans hypersensitive to PTBP-F-R. No simultaneous reactions or cross-reactions were shown to formaldehyde, p-tert-butylphenol, p-tert-butylcatechol, 2(3)-tert-butyl-4-hydroxyanisole (BHA) or 3,5-di-tert-butyl-4-hydroxytoluene (BHT). It was also shown that low amounts of contaminants in the test substances, if not taken into account, could influence the conclusions drawn from the test results obtained.

Sensitizing capacity of some trimers in p-tert-butylphenol-formaldehyde resin

Contact allergy to p-tert-butylphenol formaldehyde resin (PTBP-F-R) is not rare. This resin consists of a large number of substances, most of which are still unknown. For diagnostic and preventive reasons the chemical identity of the sensitizers should be known, as well as their sensitizing capacities, cross-reaction patterns and presence in the environment. The aims of this study were to investigate the sensitizing capacities and potential cross-reacting patterns for 4-tert-butyl- 2,6-bis-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl)-phenol (XIII), 4-tert-butyl-2- (5 - tert - butyl - 2 - hydroxy-benzyloxymethyl) - 6 - (5 - tert - butyl - 2 - hydroxy - 3 - hydroxymethyl-benzyloxy methyl)-phenol (XIVa) and 7,15,23-tri-tert-butyl-25,26,27-trihydroxy-2,3,10,11,18,19-hexahomo-3,11,19-trioxacalix(3)arene (XVIII) by the guinea pig maximization test. 4-tert-Butyl-2,6-bis-hydroxymethyl-phenol, 4-tert-butylbenzene-1,2-diol, 4-tert-butyl-2-hydroxymethyl-phenol, 4-tert-butyl-phenol, 4-tert-butyl-2-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl)-6-hydroxymethyl-phenol, 4-tert-butyl-2-[5-tert-butyl-3-(5-tert-butyl-2-hydroxy-3-hydroxymethyl-benzyloxymethyl) - 2 -hydroxy-benzyloxymethyl] - 6 - (5 - tert-butyl- 2 -hydroxy- 3 -hydroxymethyl-benzyloxymethyl)- phenol and were used as potential cross-reacting substances. In this study it is strongly indicated that the linear trimer XIII has a sensitizing capacity in the guinea pig which was significant when compared to the controls (p = 0.024). No cross-reactions were detected in animals induced with the linear trimer XIII. The linear trimer XIVa and the cyclic trimer XVIII failed to induce sensitization.

Occupational dermatoses among fibreglass-reinforced plastics factory workers

Fibreglass-reinforced plastics (FRP) factory workers are at high risk of developing occupational dermatoses because of their exposure to many chemicals used in the manufacture of plastics as well as to glass fibre or dust. Patch tests were carried out on 29 workers involved in FRP manufacturing processes where unsaturated polyester (UP) resin was used, to investigate the causes of their skin problems. Of the 22 workers who reported experiencing skin problems, 16 showed positive results to at least 1 chemical, including 6 cases of multiple sensitivity. 2 showed positive reactions to UP base resin, 6 to cobalt chloride, 5 to benzoyl peroxide (BPO), 4 to methyl ethyl ketone peroxide (MEKPO), 2 to para-tertiary butyl catechol (PTBC), 1 to styrene and 1 to formaldehyde. After taking into account their exposures and reported causes by questionnaires and their patch test results, 7 cases were diagnosed as allergic contact dermatitis (ACD) due to chemicals, 3 as irritant contact dermatitis (ICD) due to chemicals, and 3 as dermatitis due to mechanical irritation (MI) from glass fibre or dust, as well as 9 as ACD and/or MI. 18 of the total of 29 subjects (62.1%), including 2 workers without a history of skin problems, were sensitized to at least 1 chemical. Cobalt, peroxides, PTBC and UP base resin were the common causes of ACD.

Patch testing for permanent-press allergic contact dermatitis

During the decade of the 90s, 24 cases of permanent-press textile-resin contact dermatitis were identified. The most common allergen associated with these cases was dimethylol propylene urea (DMPU). Although previous reports had suggested ethylene urea melamine formaldehyde resin (EUMF) or dimethylol dihydroxy ethylene urea (DMDHEU) as the most appropriate test materials for this type of contact dermatitis, we could not confirm EUMF as appropriate but, with some limitations, can support DMDHEU due to its widespread and continued use. DMPU has been withdrawn from the marketplace and replaced with what may be less reactive materials. In this study, we also observed discordance between EUMF patch tests in the range of 30%, which is consistent with previous reports about the biovariability of patch test results.

Asthmagenicity of coal mine roof-bolting resins: an assessment using inhalation provocation tests

Inhalation provocation tests were used to assess whether the volatile products of an activated resin had caused occupational asthma in a non-random sample of six asthmatic coal miners. The resin system uses the polymerization of polyester and styrene under the influence of the cross-linking agent dibenzoyl peroxide to secure roof, wall and floor bolts in mine tunnels. The tests were conducted sequentially in a double-blind fashion over a 'dose' range which extended just beyond the maximum likely to have been experienced occupationally during a single day's work. The tests were monitored by symptoms, changes in the forced expiratory volume in 1 s (FEV1) and changes in airway responsiveness. All subjects completed the series of tests without any significant decrements in FEV1 or significant increases in airway responsiveness. We conclude that the use of this resin system is not likely to have been the cause of the asthma in the test subjects, nor in the larger group of miners of which they were a sample, but neither possibility is fully excluded and the participants may not have been adequately representative of other asthmatic coal miners.

Sensitizing capacity of 5,5'-di-tert-butyl-2,2'-dihydorxy-(hydroxymethyl)-dibenzyl ethers in the guinea pig

In patients hypersensitive to p-tert-butylphenol-formaldehyde resin (PTBP-F-R), it is for diagnostic, therapeutic and preventive reasons necessary to know the identity of the primary sensitizing substances, their sensitizing capacities as well as their cross-reaction patterns. We have recently shown that the 2 dimers in PTBP-F-R, 5,5'-di-tert-butyl-2,2'-dihydroxy-3-hydroxymethyl-dibenzyl ether (X) and 5,5'-di-tert-butyl-2,2'-dihydroxy-3,3'-dihydroxymethyl-dibenzyl ether (IX) are contact sensitizers in man. The aim of this study was to investigate the sensitizing capacities of these dimers in PTBP-F-R and potential cross-reacting substances in the guinea pig with the guinea pig maximization test. IX, X, 2,6-dimethylol-p-tert-butylphenol (2,6-MPTBP), 2-methylol-p-tert-butylphenol (2-MPTBP), p-tert-butylcatechol (PTBC), 5,5'-di-tert-butyl-2,2'-dihydroxy-dibenzyl ether (XI) were used as possible cross reacting substances. IX and X were shown to be sensitizers. When compared to the sensitizers in phenol-formaldehyde resin, IX is a strong sensitizer (p= 0.00052) and X a moderate sensitizer (p=0.0053). Animals sensitized to IX showed cross-reactions to X (p=0.010), 2,6-MPTBP (p=0.0011) and PTBC (p=0.0498). Animals sensitized to X showed no cross-reactions to the substances that were tested. The results indicate that IX is a main allergen in PTBP-F-R, with possibly also X.

The osmotic swelling characteristics of cardiac valve prostheses

Several types of mechanical cardiac prostheses have been constructed with Delrin occluders, a material that is subject to osmotic swelling. The leaftets are designed to expand to specific tolerances when immersed in blood. The synthetic blood analogs commonly used in vitro contain hydrophilic compounds that can alter the osmotic expansion of the Delrin occluders. A static leak test chamber was employed to illustrate the effects of various test fluids on the sustained regurgitation phase of Delrin valves.

Contact allergy to 5,5'-di-tert-butyl-2,2'-dihydroxy-(hydroxymethyl)-dibenzyl ethers, sensitizers, in p-tert-butylphenol-formaldehyde resin

Allergy to p-tert-butylphenol-formaldehyde resin (PTBP-F-R) is not rare. This resin consists of a large number of substances, most of which are still unknown. More knowledge about the sensitizers in the resin is a good basis for development of diagnosis, treatment and prevention. The aim of this investigation was to study allergens in PTBP-F-R by isolation of some medium molecular weight substances from the resin and patch testing these in individuals hypersensitive to PTBP-F-R. 2 isolated substances were shown to be allergens in PTBP-F-R, 5,5'-di-tert-butyl-2,2'-dihydroxy-3,3'-dihydroxymethyl-dibenzyl ether and 5,5'-di-tert-butyl-2,2'-dihydroxy-3-hydroxymethyl-dibenzyl ether. 13 patients hypersensitive to PTBP-F-R were patch tested with serial dilutions of 5,5'-di-tert-butyl-2,2'-dihydroxy-3,3'-dihydroxymethyl-dibenzyl ether and 12 of them reacted positively. 12 patients hypersensitive to PTBP-F-R were patch tested with serial dilutions of 5,5'-di-tert-butyl-2,2'-dihydroxy-3-hydroxymethyl-dibenzyl ether and 11 of them reacted positively. Positive patch test reactions were seen down to 0.0000025 mmole x 1(-1) (approximately 0.01 ppm) for both 5,5'-di-tert-butyl-2,2'-dihydroxy-3,3'-dihydroxymethyl-dibenzyl ether and 5,5'-di-tert-butyl-2,2'-dihydroxy-3-hydroxymethyl-dibenzyl ether in the most sensitive patient. HPLC analysis of 2 PTBP-F-Rs showed the presence of 1.0-1.7% w/w 5,5'-di-tert-butyl-2,2'-dihydroxy-3,3'-dihydroxymethyl-dibenzyl ether and 0.75-0.90% w/w 5,5'-di-tert-butyl-2,2'-dihydroxy-3-hydroxymethyl-dibenzyl ether in the resins.

Acute abdomen with colonic necrosis induced by Kayexalate-sorbitol

Colonic necrosis is an unusual complication after treatment of hyperkalemia with sodium polystyrene sulfonate (SPS, Kayexalate) in sorbitol. To increase awareness of this complication, we report a case of necrosis of the transverse colon in a patient given oral and rectal SPS-sorbitol for hyperkalemia. Colonic necrosis was manifested as an acute abdomen within 24 hours of initial administration. Prompt surgical resection of the necrotic transverse colon permitted rapid recovery of bowel function. Although SPS crystals are seen microscopically in the necrotic bowel, experimental evidence implicates the sorbitol component of the SPS-sorbitol in the pathogenesis of colonic necrosis. A high index of suspicion for the unusual complication of colonic necrosis after oral or rectal administration of SPS-sorbitol may allow prompt recognition and surgical cure.

Allergic contact dermatitis in dentistry

Allergic contact dermatitis (ACD) in dentistry may affect dentists and orthodontists, technicians, nurses and patients. Changes to dental practice in recent years have altered the reported frequencies of allergens causing ACD in both dental personnel and patients. Allergic contact dermatitis to medicaments, metals and glutaraldehyde were previously common allergens in dentistry; however, widespread adoption of rubber gloves by staff has resulted in a significant increase in ACD to glove allergens in both dental staff and their patients, while affording protection against the traditional allergens. Both public concerns about potential toxicity of metals in oral restorations and a greater demand for cosmetic dentistry, have resulted in greater use of acrylics and resins by dental personnel, exposing them to highly allergenic materials. Dermatologists need to be aware of the newer allergenic materials used in dentistry in order to correctly manage skin diseases in this high-risk group.

Occupational dermatoses in composite production

In a plant that produces fiber-resin composite by impregnation of cellulose fibers with phenol-formaldehyde and melamine-formaldehyde resins, a new technique was introduced that resulted in problems in the handling of uncured products. Many workers suffered dermatitis on areas of exposed skin. A primary investigation found that some workers had an occupationally related skin disease with contact allergy to work materials. We undertook a survey of occupational dermatoses, based on a questionnaire, clinical examination, and patch test with a standard series and a series of products and chemicals representing the work environment. Eighty-eight workers participated in the clinical investigation. In six workers, contact allergy to phenol-formaldehyde resin was seen, and in five workers, contact allergy to melamine-formaldehyde resin was noted. Two workers were allergic to both resins. Occupational dermatitis was diagnosed in nine of 88 (10.2%) workers. In this article, we discuss possible preventive measures for avoiding occupational dermatitis.

Cytocompatibility of periodontal dressing materials in fibroblast and primary human osteoblast-like cultures

Purpose of this investigation was to determine the cytocompatibility of various periodontal dressing materials by means of human primary gingival fibroblasts (HGF), human osteoblast-like cells (HObl) derived from the alveolar bone, and permanent 3T3 mouse fibroblasts (3T3). Cell culture medium extracts (time periods of extraction: day 1 and between day 2 and day 8 after setting) as well as solid specimens of the following materials were investigated: Coe-pak, Voco pac, Peripac, and Barricaid. Responses of cultures exposed for 24 h and 48 h to these materials were monitored by the fluorescent dyes H33342 and sulforhodamin 101 as well as by light microscopy. It was found that most extracts of Voco pac, Peripac, and Barricaid did not inhibit growth of HGF. Coe-Pak, however, clearly reduced the proliferation of HGF compared to untreated controls. Peripac decreased growth of HObl whereas Coe-Pak, Voco pac, and Barricaid caused no cytotoxic alterations in any of the test assays. Contrary to HGF and HObl, 3T3 cells were much more irritated by the test materials. But the light-curing resinous material Barricaid reduced proliferation of 3T3-fibroblasts only slightly. Our data indicate that Barricaid is exceedingly cytocompatible, whereas all other materials revealed moderate or severe cytotoxic effects according to the cell type.