Steven Sadhra

High-performance liquid chromatography of unmodified rosin and its applications in contact dermatology

Rosin is a well recognised skin sensitiser and is also amongst the most common causes of occupational asthma. Due to its complex chemical composition, it is difficult to isolate its many components and this has hindered progress in the identification of the specific respiratory and contact allergens it contains. This paper reports the application of high-performance liquid chromatography and other analytical techniques to the isolation and identification of contact allergens in complex mixtures such as rosin. HPLC methods were developed in order to isolate as many rosin components as possible and these were then patch tested on rosin sensitive individuals. The structure of the most dermatologically active component was then determined using mass spectrometry, nuclear magnetic resonance and infrared techniques. An HPLC method has also been developed which will enable the identification of rosin in commercial products, providing a valuable tool for determining the cause of rosin contact allergy. Furthermore, mass spectral data for the common abieitic-type resin acids are compiled which were used to confirm the identification of the HPLC resin acid peaks and have not been reported previously.

Sensitisation to natural rubber latex : an epidemiological study of workers exposed during tapping and glove manufacture in Thailand

OBJECTIVES To estimate the prevalence of sensitisation to natural rubber latex in latex tappers and latex glove factory workers, and to relate this to airborne exposure to latex. METHODS Five hundred workers employed in three latex glove factories, 314 tappers, and 144 college students (control group) were studied. The workers in the glove factories were classified into three exposure groups; high, moderate, and low. Personal exposures to natural rubber latex aeroallergens were measured by immunoassay. Symptom questionnaires and skin prick tests with latex allergens (Stallergènes 1:200 w/v) and other common environmental allergens were performed. The criterion for positivity was a wheal reaction at least 3 mm in diameter greater than that to a diluent control. RESULTS The geometric mean (GM) concentration of latex in air was 15.4 μg/m3for those employed in glove stripping, glove inspections, and packing of powdered gloves. The moderate exposure glove manufacturing group and the tappers had GM concentrations of 2.3 and 2.4 μg/m3respectively, compared with United Kingdom users of latex powdered gloves,who had GM concentrations of 0.5 μg/m3. The prevalence of sensitisation to latex in the tappers and latex glove factory workers was 1.3% and 1.7% respectively. No positive cases were found among the college students. Workers who showed a positive skin prick test to latex were more likely to be atopic. Work related respiratory and dermatological symptoms were found in about 20% of each population studied, but were not related to the presence of positive latex prick tests. CONCLUSIONS This study suggests that in the Thai latex industries, latex sensitisation is rare despite high concentrations of airborne exposure and is less prevalent than in the healthcare sector in Europe where skin exposure is greater.

Oxidation of resin acids in colophony (rosin) and its implications for patch testing

Commercial preparations of colophony (rosin) used for patch testing are made from unmodified rosin in pet. and may be stored for some considerable time before being used. This would be satisfactory if the composition and dermatological activity of the preparations were both reproducible and stable, but investigations by the authors have shown that the resin acids undergo progressive and substantial oxidation and that the dermatological activity of the preparations increases significantly with time. This may be a cause of inconsistent patch test results unless the composition can be stabilized. Gas liquid chromatography (GLC) analysis of a raw rosin sample and its commercial patch test preparation has shown that they both contained the same resin acids, but the concentration of the abietic type resin acids was found to be lower in the patch test preparations. The degradation of resin acids is due to their atmospheric oxidation, which may occur during the preparation and storage of the commercial rosin patch test preparation. The susceptibility of individual resin acids to atmospheric oxidation was demonstrated by analysing a sample of raw Portuguese gum rosin, which was then left exposed to air and light. Most of the resin acids were found to undergo oxidation at a rate which gradually diminished. More importantly, it is presumed that the concentration of oxidized resin acids increased correspondingly, and these have been shown to be more dermatologically active than the unoxidised resin acids. The rate of decrease of resin acid concentration was found to be in the following order: neoabietic > levopimaric and palustric > abietic > dehydroabetic acid. The pimaric type resin acids were found to be relatively inert to atmospheric oxidation when compared with the abietic type resin acids. Patch testing with the resulting partly oxidized Portuguese rosin produced positive reactions at a 35% higher frequency than the raw Portuguese rosin. The study demonstrates that the allergic potential of unmodified rosin may increase with exposure to air and light. It is therefore recommended that rosin preparations are analysed routinely as part of a quality control programme, which will enable better validation and comparison of patch test results from different dermatological centres. Since the oxidized resin acids are the main allergens in unmodified rosin, it is important that the concentration of the oxidized resin acids is kept high as well as constant in commercial patch test preparations.

Urinary Concentrations of Toxic Substances: An Assessment of Alternative Approaches to Adjusting for Specific Gravity

Alternative approaches of adjusting urinary concentration of cadmium for differences in specific gravity of biological samples were assessed. The main analysis used 2922 cadmium-in-urine samples collected in the period 1968–1989 from workers at a UK nickel-cadmium battery facility. Geometric means of cadmium-in-urine, adjusted and unadjusted for specific gravity, were obtained for 21 different values of specific gravity ranging from 1.010 to 1.030. There was a highly significant positive trend (P < 0.001) of unadjusted cadmium-in-urine with specific gravity. Conventional adjustment for specific gravity led to a highly significant negative trend (P < 0.001) of adjusted cadmium-in-urine with specific gravity, SG. An approach proposed by Vij and Howell, involving the introduction of a z coefficient, led to satisfactory adjustment. Conventional adjustment of specific gravity leads to overcompensation of the confounding effects of specific gravity. An alternative method is available and should probably be adopted when interpreting urine biological samples for all chemical substances.

Identification of contact allergens in unmodified rosin using a combination of patch testing and analytical chemistry techniques

Summary In order lo investigate the contact allergens in the unmodified colophony (rosin) used in routine patch testing, preparative chromatographic techniques were used to separate its components which were then patch tested on colophony‐sensitive individuals. The chemical structure of the dermatologically active components was elucidated using mass spectrometry, nuclear magnetic resonance and infra‐red techniques. The study shows that oxidized resin acids are stronger sensitizers than the resin acids themselves, the most potent contact allergen being 7‐oxydehydroahietic acid (purity 92%). At naturally occurring concentrations (relative to abietic acid) all unoxidized resin acids were found to play an insignificant part, individually, in colophony dermatitis, except abietic acid (purity 99%), which was found to be a weak but important allergen. The commercial Trolab abietic acid preparation (unknown purity) was found to be dermatologically more active than purified abietic acid.

Occupations associated with COPD risk in the large population-based UK Biobank cohort study

Objectives Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Exposure to occupational hazards is an important preventable risk factor but the contribution of specific occupations to COPD risk in a general population is uncertain. Our aim was to investigate the association of COPD with occupation in the UK population. Methods In 2006–2010, the UK Biobank cohort recruited 502 649 adults aged 40–69 years. COPD cases were identified by prebronchodilator forced expiratory volume in 1 s/forced vital capacity<lower limit of normal according to American Thoracic Society (ATS)/ European Respiratory Society (ERS) guidelines. Current occupations were coded using the Standard Occupational Classification (SOC) 2000. Prevalence ratios (PRs) and 95% CIs of COPD for each SOC-coded job were estimated using a robust Poisson model adjusted for sex, age, recruitment centre and lifetime tobacco smoking. Analyses restricted to never-smokers and non-asthmatics were also performed. Results Of the 353 occupations reported by 228 614 current working participants, several showed significantly increased COPD risk. Those at highest COPD risk were seafarers (PR=2.64; 95% CI 1.59 to 4.38), coal mine operatives (PR=2.30; 95% CI 1.00 to 5.31), cleaners (industrial: PR=1.96; 95% CI 1.16 to 3.31 and domestic: PR=1.43; 95% CI 1.28 to 1.59), roofers/tilers (PR=1.86; 95% CI 1.29 to 2.67), packers/bottlers/canners/fillers (PR=1.60; 95% CI 1.15 to 2.22), horticultural trades (PR=1.55; 95% CI 0.97 to 2.50), food/drink/tobacco process operatives (PR=1.46; 95% CI 1.11 to 1.93), floorers/wall tilers (PR=1.41; 95% CI 1.00 to 2.00), chemical/related process operatives (PR=1.39; 95% CI 0.98 to 1.97), postal workers/couriers (PR=1.35; 95% CI 1.15 to 1.59), labourers in building/woodworking trades (PR=1.32; 95% CI 1.04 to 1.68), school mid-day assistants (PR=1.32; 95% CI 1.01 to 1.74) and kitchen/catering assistants (PR=1.30; 95% CI 1.10 to 1.53). Associations were similar in analyses restricted to never-smokers and non-asthmatics. Conclusions Selected occupations are associated with increased COPD risk in a large cross-sectional population-based UK study. Further analyses should confirm the extent to which these associations reflect exposures still of concern and where strengthened preventive action may be needed.

The effect of exposure to biomass smoke on respiratory symptoms in adult rural and urban Nepalese populations

BackgroundHalf of the world’s population is exposed to household air pollution from biomass burning. This study aimed to assess the relationship between respiratory symptoms and biomass smoke exposure in rural and urban Nepal.MethodsA cross-sectional study of adults (16+ years) in a rural population (n = 846) exposed to biomass smoke and a non-exposed urban population (n = 802) in Nepal. A validated questionnaire was used along with measures of indoor air quality (PM2.5 and CO) and outdoor PM2.5.ResultsBoth men and women exposed to biomass smoke reported more respiratory symptoms compared to those exposed to clean fuel. Women exposed to biomass were more likely to complain of ever wheeze (32.0 % vs. 23.5%; p = 0.004) and breathlessness (17.8% vs. 12.0%, p = 0.017) compared to males with tobacco smoking being a major risk factor. Chronic cough was similar in both the biomass and non-biomass smoke exposed groups whereas chronic phlegm was reported less frequently by participants exposed to biomass smoke. Higher PM2.5 levels (≥2 SDs of the 24-hour mean) were associated with breathlessness (OR = 2.10, 95% CI 1.47, 2.99) and wheeze (1.76, 1.37, 2.26).ConclusionsThe study suggests that while those exposed to biomass smoke had higher prevalence of respiratory symptoms, urban dwellers (who were exposed to higher ambient air pollution) were more at risk of having productive cough.

Hearing loss in British Army musicians

BACKGROUND Military musicians increasingly fulfil front line roles. Existing literature suggests that musicians are at greater risk of hearing loss than the general population. It is important to ascertain whether these findings apply to military musicians if they are to be placed in operational acoustically hazardous environments. AIMS To compare hearing loss between groups of British Army musicians and with their administrative (non-musician) counterparts. METHODS Routine health surveillance audiometric data for a group of military musicians were compared with military administrative staff during the first 8-12 years of their careers. Structured interviews were used to identify those meeting the study inclusion criteria (8 year minimum service, no significant, relevant medical history, no previous extraordinary loud noise exposure, service within study employment group throughout military career), and to clarify the instrument played. RESULTS Eighty-four musicians and 44 administrators participated. Using the Health & Safety Executives (HSEs) age- and gender-correcting system, 12 (14%) musicians and 9 (20%) non-musicians had a deterioration in hearing. The overall odds ratio for developing hearing loss in musicians was 0.65 (95% CI 0.25-1.68). Compared with woodwind instrumentalists, the odds ratio for hearing loss in brass instrumentalists was 2.00 (95% CI 0.85-3.44) and for percussionists 1.83 (95% CI 0.77-2.90). CONCLUSIONS The findings suggest that military musicians are at no greater risk of hearing loss than their administrative counterparts after 8-12 years in service. This may represent a healthy-worker effect. There is no statistically significant differential risk of hearing loss between different instrumental groups.

Risks of cataract in Nigerian metal arc welders

BACKGROUND Occupational exposure to ultraviolet (UV) radiation from welding is considered a risk factor for cataract and other eye disorders, but the evidence for such effects is limited. AIMS To identify any increased risk of developing cataract from metal arc welding and to investigate the associated risk factors. METHODS A cross-sectional study was carried out on male welders and control subjects (not engaged in welding) from five fabrication and construction companies in Port Harcourt, Nigeria. A questionnaire was used to gather information regarding their demography and lifestyle, along with their occupational, medical and ocular histories. Cataract was identified by external examination and ophthalmoscopy. RESULTS A total of 117 welders and 105 controls participated. There was no statistically significant increase in the risk of cataract in welders after adjusting for age, smoking status, family history of cataract, outdoor work and history of eye injury. There was a strong association between work-related eye-injury history and cataract. Only 60% of welders were wearing eye protection when the eye injury occurred. The majority of the eye injuries (72%) occurred during welding and grinding operations. CONCLUSIONS The findings of this study suggest that the main occupational risk factor for cataract was a history of eye injuries. The role of UV (or optical) radiation appeared to be less important than impact eye injuries associated with welding-allied processes. It is therefore important that welders are provided with different types of eye protection and are informed about which type should be used, and when, so that they can be protected against optical and impact injuries.

Occupational dermatitis from Synacril Red 3B liquid (Cl Basic Red 22)

A carpet factory worker, exposed to a number of different dyes, developed a Severe hand dermatitis. The handling of warm, wet and freshly‐dyed yarn with unprotected hand was thought to have caused the onset of dermatitis Patch testing indicated that the patient was sensitive to only one of the dyes handled, namely Synacril Red 3B liquid, which is based on the single dyestuff Basic Red 22 (CI 11055). Chemical analysis revealed the dyestuff to be of high purity (>95%). suggesting that sensitization was caused by the Basic Red 22 dyestuff itself and not by an avoidable impurity.