Contact allergy to woods

Allergic contact dermatitis to woods of the genus Dalbergia in musical instruments

BACKGROUND

The woods of trees of the genus Dalbergia are a frequent cause of allergic contact dermatitis.

OBJECTIVES

To describe the different patterns of symptoms and sensitisation to woods of the genus Dalbergia in four patients whose regular work is linked to music, either as performers (two patients) or instrument makers.

RESULTS

The patients showed extensive cross-reactivity between the different Dalbergia woods. The two musicians exhibited symptoms exclusively in the contact areas, while the instrument makers showed a pattern of airborne symptoms. The period from sensitisation to the development of symptoms varied greatly among the patients.

CONCLUSIONS

The symptoms of allergic contact dermatitis to Dalbergia woods differ markedly depending on the route of contact. Cross-reactivity between the woods of this genus is very wide. The sensitising potential varies between the various Dalbergia woods, which require different contact periods depending on their sensitising power.

Quinones from Cordia species from 1972 to 2023: isolation, structural diversity and pharmacological activities

Plants of the genus Cordia (Boraginaceae family) are widely distributed in the tropical regions of America, Africa, and Asia. They are extensively used in folk medicine due to their rich medicinal properties. This review presents a comprehensive analysis of the isolation, structure, biogenesis, and biological properties of quinones from Cordia species reported from 1972 to 2023. Meroterpenoids were identified as the major quinones in most Cordia species and are reported as a chemotaxonomic markers of the Cordia. In addition to this property, quinones are reported to display a wider and broader spectrum of activities, are efficient scaffold in biological activity, compared to other classes of compounds reported in Cordia, hence our focus on the study of quinones reported from Cordia species. About 70 types of quinones have been isolated, while others have been identified by phytochemical screening or gas chromatography. Although the biosynthesis of quinones from Cordia species is not yet fully understood, previous reports suggest that they may be derived from geranyl pyrophosphate and an aromatic precursor unit, followed by oxidative cyclization of the allylic methyl group. Studies have demonstrated that quinones from this genus exhibit antifungal, larvicidal, antileishmanial, anti-inflammatory, antibiofilm, antimycobacterial, antioxidant, antimalarial, neuroinhibitory, and hemolytic activities. In addition, they have been shown to exhibit remarkable cytotoxic effects against several cancer cell lines which is likely related to their ability to inhibit electron transport as well as oxidative phosphorylation, and generate reactive oxygen species (ROS). Their biological activities indicate potential utility in the development of new drugs, especially as active components in drug-carrier systems, against a broad spectrum of pathogens and ailments.

Valorizing urban forestry waste through the manufacture of toys

Urban forestry generates a huge amount of waste worldwide, resulting from the processes of pruning and suppression. Disposal in landfills reduces the useful life of these facilities and forgoes the possibility of generating income from the waste. This study investigated the manufacture of toys as a strategy to valorize urban forestry waste. For this, physical-mechanical, chemical (extractive), color and shape characterizations were performed for three species of urban trees commonly planted in Brazil, a region of Neotropical forests. Toy prototypes were developed and manufactured from wood waste. Regarding color, all studied species showed high value of the variable b*, which refers to the blue-yellow axis. Handroanthus heptaphyllus wood had the highest values of basic density (0.706 g.cm^-3) and Janka hardness (1142, 1027 and 1669 kgf.cm^-2 for radial, tangential and transverse directions, respectively), and had the lowest volumetric shrinkage (11.38%). The lowest content of total extractives was measured in Handroanthus heptaphyllus, 6.33%, and the greatest content was found in Spathodea campanulata, 7.01%. The average value suggested for the toy prototypes varied between $ 3.70 and $ 13.58. The urban pruning wastes of the species studied have physical, chemical and mechanical attributes suitable for the manufacture of toys. This use has strong potential for environmental, economic and social sustainability and the toys are pedagogically accepted by adults and children.

Determinants of wood dust exposure in the Danish furniture industry--results from two cross-sectional studies 6 years apart

Objectives: This paper investigates determinants of wood dust exposure and trends in dust level in the furniture industry of Viborg County, Denmark, using data from two cross-sectional studies 6 years apart.

Methods: During the winter 1997/1998, 54 factories were visited (hereafter study 1). In the winter 2003/2004, 27 factories were revisited, and personal dust measurements were repeated. In addition, 14 new factories were included (hereafter study 2). A total of 2303 woodworkers participated in study 1, and 2358 measurements from 1702 workers were available. From study 2, 1581 woodworkers participated and 1355 measurements from 1044 workers were available. Information on occupational variables describing potential determinants of exposures like work task, exhaust ventilation, enclosure and cleaning procedures were collected. A total of 2627 measurements and 1907 persons were included in the final mixed model in order to explore determinants of exposure and trends in dust level.

Results: The overall inhalable wood dust concentration (geometric means (geometric standard deviation)) has decreased from 0.95 mg/m³ (2.05) in study 1 to 0.60 mg/m³ (1.63) in study 2, representing a 7% annual decrease in dust concentration, which was confirmed in the mixed model. From study 1 to study 2 there has been a change towards less manual work and more efficient cleaning methods, but on the contrary also more inadequate exhaust ventilation systems. The following determinants were found to ‘increase’ dust concentration: sanding; use of compressed air; use of full-automatic machines; manual work; cleaning of work pieces with compressed air; kitchen producing factories and small factories (<20 employees). The following determinants of exposure were found to ‘decrease’ dust concentration: manual assembling/packing; sanding with adequate exhaust ventilation; adequate exhaust ventilation; vacuum cleaning of machines and special cleaning staff.

Conclusions: Despite a substantial drop in the dust concentration during the last 6 years in the furniture industry in Viborg County, further improvements are possible. There should be more focus on improved exhaust ventilation, professional cleaning methods and avoiding use of compressed air.

Airborne contact dermatitis in gaitas (flageolets) constructors after exposure to sawdust of caviuna

Exotic wood species are used in the manufacture of furniture, musical instruments, tool handles, and other wooden items. Exposure to sawdust of the wood can produce dermatitis on exposed areas in woodworkers. We studied 7 patients, gaitas constructors who used caviuna wood to make their instruments. They developed dermatitis on exposed areas hours after they had begun to work with caviuna. We performed patch tests using the European standard series, caviuna sawdust sample, and a series of dalbergiones. 15 controls were performed. Two caviuna samples provided by a patient were analysed by thin-layer chromatography (TLC). Patch test with caviuna sawdust yielded positive reactions in all patients. 5 of the 7 sufferers reacted strongly to obtusaquinine and (R)-4-methoxydalbergione deriving from Dalbergia retusa, but also to sensitizers present in other rosewoods. Patch tests with R-3,4-dimethoxydalbergione deriving from Machaerium scleroxylum remained negative in the patients, as well as in control subjects. The TLC analysis of the samples showed that the woods could have been M. scleroxylum, D. cearensis or D. frustescens, but not D. retusa. In our patients, airborne contact dermatitis was caused by exposure to caviuna sawdust. The patients must have been in contact with different Dalbergia species and especially with D. retusa.

Toilet seat contact dermatitis

Allergic contact dermatitis to wooden toilet seats was a previously well-recognized pattern of regional dermatitis. We report a recent occurrence in a child that highlights a possible resurgence in this presentation, associated with the increasing popularity of wooden toilet seats.

Occupational allergic contact dermatitis caused by wood dusts

Exposure to wood dusts may cause various skin and mucosal symptoms. Allergic dermatoses, caused by wood dusts, diagnosed at the Finnish Institute of Occupational Health during 1976-1999 are reported here. 16 had allergic contact dermatitis and, 2 had contact urticaria. 9 men (3 cabinet makers, 3 joiners, 1 carpenter, 1 knifemaker and 1 machinist) were mainly exposed to tropical hardwoods. 1 man had dermatitis caused by western red cedar. 5 patients, 3 men and 2 women, were exposed to Finnish pine or spruce dusts, and 1 man to aspen. 7 also had rhinitis, 4 asthma or dyspnoea and 3 conjunctivitis. On patch testing, 10 men reacted to 9 different wood dusts, including teak (5), palisander (3), jacaranda (2), mahogany (2), walnut (2) and obeche (1). Reactions to wood allergens, including lapachol (2), deoxylapachol (1), (R)-3,4-dimethoxydahlbergione (2), 2,6-dimethoxy-1,4-benzoquinone (1), mansonone A (2) and salicyl alcohol (1), were noted in 4 cases. All but 1 of 5 patients exposed to pine or spruce dusts reacted to the sawdusts, all 5 to colophonium, 3 to abietic acid, 2 to tall oil resin, 3 to wood tar mix and 4 to other wood gum resins. Of the 2 CU patients, 1 was prick and RAST positive to obeche, 1 reacted with urticarial dermatitis to punah wood dust on chamber exposure. Occupational allergic dermatoses are mainly caused by the dusts of hardwoods, mostly due to Type IV allergy, but may also be caused by softwood dusts. Patch tests can be done with wood dusts, but should be confirmed by patch testing with wood allergens if possible.

Skin symptoms and contact allergy in woodwork teachers

To estimate the occurrence of skin symptoms and the prevalence of contact allergy to occupational allergens, 84 male woodwork teachers were interviewed, clinically examined and patch tested. The tests included a supplemented European standard series and acetone extracts of wood dust of pine, spruce, juniper and birch. In addition, 10 colophony-allergic volunteers were tested with dilution series of wood dust extracts. Major colophony compounds in the dust extracts were analyzed with gas chromatography. We found a high 1-year period prevalence of generally mild hand eczema: 19%. Contact allergy was diagnosed to several allergens in the working environment, e.g., benzisothiazolin-3-one, nickel, formaldehyde and colophony. A clear relationship between patch test reactions to colophony and to coniferous woods, especially pine, was found. Exposure to wood dust at work caused dermatitis in a colophony-sensitized teacher.