Side-by-side comparison of an open-chamber (TM 300) and a closed-chamber (Vapometer™) transepidermal water loss meter.

BACKGROUND: The measurement of transepidermal water loss (TEWL) is used to monitor changes in the stratum corneum's permeability to water vapor. This measurement is widely used in the cosmetics industry and in dermatology research. However, only limited work has been undertaken to assess the comparability of results from different TEWL meters over an extended range of measurements. METHODS: This study compared the results of TEWL measurements between two commonly used open-chamber and closed-chamber TEWL devices. Five hundred and forty measurements were taken in 17 participants on the dorsum and palm of both hands on two different days and the order of the devices was randomized. RESULTS: The results showed that the open TEWL meter's capacity for measuring high values of TEWL was restricted, and that the closed-chamber TEWL meter was less sensitive to differences in the lower range of measurements. CONCLUSION: Both devices have their strengths for different applications, but their results cannot be directly compared. We were unable to find a statistical model that would allow us to transform the measurements made on one device for a comparison with the results generated by the other device.

A case-control study of Parkinson's disease and tobacco use: gene-tobacco interactions.

A case-control study of genetic, environmental, and occupational risk factors for Parkinson's disease (PD) was carried out in five European countries (Italy, Malta, Romania, Scotland, and Sweden) to explore the possible contribution of interactions among host and environmental factors in sporadic PD. Whereas smoking habits confirmed its negative association with PD, a possible modulatory role of genetic polymorphisms was investigated to obtain further mechanistic insights. We recruited 767 cases of PD and 1989 age-matched and gender-matched controls. Participants completed an interviewer-administered questionnaire including the history of smoking habits. The polymorphisms of genes involved either in metabolism of compounds contained in tobacco smoke (CYP2D6, CYP1B1, GSTM1, GSTT1, GSTM3, GSTP1, NQO1, SOD2, EPHX and NAT2) or in dopaminergic neurotransmission (MAOA, MAOB, DAT1 and DRD2) were characterized by PCR based methods on genomic DNA. We found evidence of statistically significant gene-tobacco interaction for GSTM1, NAT2, and GSTP1, the negative association between tobacco smoking and PD being significantly enhanced in subjects expressing GSTM1-1 activity, in NAT2 fast acetylators, and in those with the GSTP1*B*C haplotype. Owing to the retrospective design of the study, these results require confirmation.

Solvent exposure and cognitive ability at age 67: a follow-up study of the 1947 Scottish Mental Survey.

OBJECTIVES: Organic solvent exposure may be associated with cognitive impairment in later life although the evidence for this association is inconsistent. This study sought to examine the association between organic solvent exposure and cognitive function in later life. METHODS: A prospective longitudinal study set in Aberdeen, Scotland examined 336 men and women born in 1936 who participated in the 1947 Scottish Mental Survey. Cognitive function at age 67 years was measured using the Trail Making Test B (TMT B), the Digit Symbol (DS) test, and the Auditory Verbal Learning Test (AVLT). Occupational hygienists reviewed occupational histories, blind to cognitive function, and estimated lifetime solvent exposures. Multiple regression analyses were employed to explore the association between solvent exposure and cognitive performance after adjustment for confounders. RESULTS: After adjusting for childhood IQ, smoking, alcohol and sex, the solvent exposed group took on average almost 10 s longer than the unexposed group to complete the TMT B, a highly significant difference. For the DS test, after adjusting for childhood IQ, smoking and gender, the exposed group scored on average two points lower than the unexposed group, which was again highly significant. There was no evidence of an effect for cumulative solvent exposure on the TMT B or DS test. For the AVLT there were no significant differences associated with exposure. CONCLUSIONS: This study of subjects with generally low exposures, found no clear evidence of an association between solvent exposure and cognitive function.

Hearing symptoms and audiometry in professional divers and offshore workers.

AIMS: The aims are to compare hearing loss between professional divers and offshore workers and to study whether hearing loss symptoms reflected physical disorder. A secondary objective was to study total threshold shift assessment as a method of detecting noise-induced hearing loss (NIHL). METHODS: Participants (151 divers and 120 offshore workers) completed a questionnaire for symptoms and screening audiometry. Audiograms were assessed for total threshold shift at 1, 2, 3, 4 and 6 kHz and the prevalence of referral (within population 5th centile) or warning levels (within population 20th centile) of hearing loss. Audiograms were assessed for an NIHL pattern at four levels by two occupational physicians. RESULTS: Hearing loss symptoms were commoner in divers at all levels of hearing loss regardless of differences between groups on audiometry. Hearing loss in offshore workers was within the population age-adjusted norm. Thirteen per cent of divers were within the 5th percentile for threshold shift for the population norm in contrast to 4% of offshore workers and this was predominantly left sided (OR 3.16, 95% CI 1.13-8.93). This difference was lost after adjustment for history of regular exposure to explosion or gunfire. Divers were more likely to have a pattern of severe NIHL on the left (OR 4.61, 95% CI 1.39-15.39, P < 0.05). Approximately 50% of participants with severe NIHL did not have a referral level of hearing loss. CONCLUSIONS: Divers suffer more NIHL than a control population. Current guidance on the assessment of total threshold shift for the detection of significant NIHL was inadequate in the sample studied.

Sharps injuries among medical students.

BACKGROUND: Medical students may be at risk of sharps injuries for several reasons. These exposures can transmit a range of blood-borne pathogens including hepatitis B, hepatitis C and human immunodeficiency virus. AIMS: To evaluate medical students' knowledge regarding the prevention and management of sharps injuries and their experience of such exposures in the calendar year 2007. METHODS: A cross-sectional, web-based, survey of fourth and fifth year medical students enrolled at the University of Aberdeen in Scotland. All students were at the mid-point of their year of study. An invitation e-mail and two electronic reminders were sent, on specified days, to the study population. These contained a summary of the study and the link to the anonymous questionnaire. RESULTS: Of the 395 medical students e-mailed, 238 (60%) responded. When compared with fourth year medical students, final year students had higher mean knowledge scores for sharps injury management (P < 0.01). Of total, 18% reported resheathing used needles and 31% reported disposing of sharps for others, indicating poor compliance with standard precautions. In the event of an injury, 29% stated that they would scrub the wound. Only 44% were familiar with policies for reporting exposures. In all, 11% of students had experienced at least one contaminated sharps injury in 2007 and, of those, 40% had reported the most recent incident. CONCLUSIONS: Medical students are at risk of sharps injuries and their knowledge regarding the prevention and management of these exposures is limited: training on these issues should be increased.

A life-course approach to the aetiology of late-onset dementias.

Substantial progress has been made in the understanding of the neurobiology of dementias, but comprehensive causal models are not available. Genetic and environmental factors probably interact to determine vulnerability to the dementias. The life-course approach to age-related diseases, when systematically applied to the dementias, provides opportunities to identify the nature and timing of environmental contributions. We discuss the relevance of the fetal origins of adult disease hypothesis to the dementias. Associations between the dementias (most often described as Alzheimer's disease) and ischaemic heart disease, obesity, hypertension, hyperlipidaemia, and non-insulin-dependent diabetes mellitus are set against associations between dementias and childhood intelligence, low educational attainments, low socioeconomic status, occupation, and lifetime dietary history. Biological mechanisms that explain how fetal development might influence the risk of adult disease may be relevant to many age-related diseases including the dementias and, possibly, to the biology of ageing.

Parkinson's disease and pesticide exposures.

INTRODUCTION: Idiopathic Parkinson's disease (PD) is a neurodegenerative disorder in which loss of dopaminergic neurons in the basal ganglia leads to tremor, bradykinesia, rigidity and postural instability. METHODS: Literature search using Medline with keywords 'Parkinson's disease' and 'pesticides', limited to English, was undertaken, supplemented by articles from the author's files. RESULTS: Many studies have found an association between pesticides and PD, but no one agent has been consistently identified. Those implicated include organochlorine insecticides, maneb and paraquat. One meta-analysis of pesticide exposure and PD found an almost doubling of risk in those exposed. Associations with specific agents may be confounded by exposure to other pesticides, making it difficult to identify the causative agent. CONCLUSIONS: The available evidence indicates that pesticides are associated with PD, but further research is needed to identify long-term biomarkers of exposure, improve methods for estimating pesticide-exposure and undertake prospective cohort studies of pesticide-exposed workers.