Bone aluminum measured in miners exposed to McIntyre powder.

A small pilot study was conducted to test whether the technique of in vivo neutron activation analysis could measure bone aluminum levels in 15 miners who had been exposed to McIntyre Powder over 40 years prior. All miners were over 60 years of age, had worked in mines that used McIntyre Powder, and were sufficiently healthy to travel from northern to southern Ontario for the measurements. Individual aluminum levels were found to be significantly greater than zero with 95% confidence (p < 0.05) in 7 out of the 15 miners. The inverse variance weighted mean of the 15 participants was 21.77 ± 2.27µgAl/gCa. This was significantly higher (p < 0.001) than in a group of 15 non-occupationally exposed subjects of a comparable age from Southern Ontario who had been measured in a previous study. The inverse variance weighted mean bone aluminum content in the non-occupationally exposed group was 3.51 ± 0.85µgAl/gCa. Since the use of McIntyre Powder ceased in 1979, these subjects had not been exposed for more than 40 years. Calculations of potential levels at the cessation of exposure in the 1970s, using a biological half-life of aluminum in bone of 10 to 20 years predicted levels of bone aluminum comparable with studies performed in dialysis patients in the 1970s and 1980s. This pilot study has shown that the neutron activation analysis technique can determine differences in bone aluminum between McIntyre Powder exposed and non-exposed populations even though 40 years have passed since exposure ceased. The technique has potential application as a biomarker of exposure in cross-sectional studies of the health consequences of exposure to McIntyre Powder.

Parvovirus B19 and mumps virus antibodies are major constituents of the intrathecal immune response in European patients with MS and increase the diagnostic sensitivity and discriminatory power of the MRZ reaction.

BACKGROUND: A positive MRZ reaction, as defined by intrathecal IgG production against at least two of its constituents, measles virus (M), rubella virus (R) and varicella zoster virus (Z), is detectable in ~ 63% of patients with multiple sclerosis (MS) and is currently considered the laboratory marker with the highest specificity and positive likelihood ratio for MS. However, M, R and Z are only the most well-established constituents of a broader intrathecal humoral immune response in MS. OBJECTIVE: To identify additional anti-microbial antibodies inclusion of which in the classical MRZ panel may result in increased sensitivity without compromising the marker's high specificity for MS. METHODS: We determined the antibody indices (AIs) for 11 viral and bacterial agents (M, R, Z, herpes simplex virus, Epstein-Barr virus, mumps virus, cytomegalovirus, parvovirus B19, Bordetella pertussis, Corynebacterium diphtheriae, and Clostridium tetani) in paired cerebrospinal fluid and serum samples from patients with MS and disease controls. RESULTS: A positive 'classical' MRZ reaction was found in 17/26 (65.4%) MS patients. The five most frequently positive AIs among patients with MS were M (76.9%), Z (61.5%), R (57.7%), parvovirus B19 (42.3%), and mumps (28%). Addition of parvovirus B19 and mumps virus to the MRZ panel resulted in an increase in sensitivity in the MS group from 65.4% to 73.1%, with 22% of the initially MRZ-negative patients exhibiting a de novo-positive response. The extended MRZ panel ('MRZplus') distinguished sharply between MS (≥ 3 AIs in 90% of all positives) and controls (varying diagnoses, from migraine to vasculitis; 0-1 AIs; p < 0.000001). The highest median AI in the MS group was found for parvovirus B19 (3.97), followed by measles virus (2.79). CONCLUSION: Inclusion of parvovirus B19 and mumps virus in the test panel resulted in an increase in the sensitivity and discriminatory power of MRZ. Our results provide a strong rational for prospective studies investigating the role of extended MRZ panels in the differential diagnosis of MS.

Management of occupational asthma: cessation or reduction of exposure? A systematic review of available evidence.

Reduction of exposure to sensitising agents causing occupational asthma has been proposed as an alternative to total avoidance in order to minimise the adverse socio-economic impact of the condition. The aim of this systematic review was to compare the effects of these two management options on asthma and socio-economic outcomes. A bibliographic search was conducted to identify studies examining the outcome of workers with occupational asthma after reduction or cessation of exposure to the causal agent. The changes in asthma symptoms and nonspecific bronchial hyperresponsiveness after reduction or cessation of exposure were described in nine and five studies, respectively. The meta-analysis of pooled data showed that a reduction of exposure was associated with a lower likelihood of improvement (OR 0.16, 95% CI 0.03-0.91) and recovery (OR 0.30, 95% CI 0.11-0.84) of asthma symptoms and a higher risk of worsening of the symptoms (OR 10.23, 95% CI 2.97-35.28) and nonspecific bronchial hyperresponsiveness (OR 5.65, 95% CI 1.11-28.82), compared with complete avoidance of exposure. This systematic review indicates that reduction of exposure cannot be routinely recommended as an alternative to cessation of exposure in the management of occupational asthma. However, further investigations are required before drawing evidence-based conclusions on the cost-effectiveness of this approach.

[Does long-term asbestos exposure cause an obstructive ventilation pattern?]. / Verursacht langjährige Asbestexposition eine obstruktive Ventilationsstörung?

This review shows that long-term exposure to asbestos-containing dust leads not only to a reduction of lung volume as well as to limitations of forced expiratory flows, such as FEF (50) and FEF (75), but also to increased frequencies of FEV (1)/FVC, and elevated airway resistance. There is evidence for significant dose-response relationships and an increase in functional changes in parallel to an increase due to the latency period. Remarkably, even asbestos workers without radiologically detectable pleural or parenchymal changes already show these functional impairments. In non-smokers, asbestos-induced lung function impairment is usually small on average, although some of these subjects show functional impairment of clinical relevance in the pathological range. In asbestos workers who also smoke, due to synergistic effects, lung function, especially of the peripheral airways, is highly significantly reduced. The use of inappropriate reference values, healthy worker effects, and airway trapping lead to an underestimation of asbestos-induced lung function impairments. There are no differences among the various occupations associated with asbestos exposure.

[Effect of asbestos fibre dust exposures on lung function--a systematic review]. / Auswirkungen der Asbestfaserstaub-Exposition auf die Lungenfunktion - ein systematisches Review.

Asbestos-induced lung diseases are in addition to skin diseases and hearing impairment due to noise the most frequent occupational diseases. In this connection, many questions arise. They particularly refer to the fine diagnostics and the compensation in case of early stages. This systematic review questions the prevailing practice of getting medical expert opinions. It was shown that already pleural plaques and low stages of lung fibrosis due to asbestos are significantly associated with symptoms of chronic obstructive bronchitis, lymphocytic alveolitis and significant functional restrictions, i. e. FVC, FEV (1) and TLC restrictions, gas exchange impairments (P ((A-a),O2), P (a,O2)), diffusion disorders (D (L,CO)) and an obstructive ventilation pattern (FEV (1)/FVC, FEF values, D (L,CO)). The asbestos fibre dose shows some relation to reductions of FVC, FEV (1), FEF values, and D (L,CO). Only about half of the asbestos-induced functional impairments are related to radiological (inclusive CT) findings. To a lesser degree, these findings also apply to exposed people without pathological chest X-ray findings. The diffusion capacity reduction, at first still within the reference range, is an early indication of a lung lesion caused by asbestos fibres. The same applies to spiroergometric parameters (P ((A-a),O2), V (E/)V (O2), V (D)/V (T)). Reduced lung compliance can also be determinable at an early asbestosis stage. The results of literature research confirmed by statements of international groups of experts indicate continuous pathophysiological processes due to asbestos fibres deposited in peripheral airways and in the lung. These processes are neither radiologically nor histopathologically detectable and occur with a chronic lymphocytic alveolitis. Therefore, diagnostics of asbestos-induced non-malignant lung and pleural changes require comprehensive lung function tests. The outcome may help to estimate the probable remaining life span.