The aim of the present study was to compare the development of vibration white fingers (VWF) in workers in relation to different ways of exposure estimation, and their relationship to the standard ISO 5349, annex A. Nineteen vibration exposed (grinding machines) male workers completed a questionnaire followed by a structured interview including questions regarding their estimated hand-held vibration exposure.Neurophysiological tests such as fractionated nerve conduction velocity in hands and arms, vibrotactile perception thresholds and temperature thresholds were determined.The subjective estimation of the mean daily exposure-time to vibrating tools was 192 minutes (range 18-480 minutes) among the workers. The estimated mean exposure time calculated from the consumption of grinding wheels was 42 minutes (range 18-60 minutes), approximately a four-fold overestimation (Wilcoxon's signed ranks test, p < 0.001). Thus, objective measurements of the exposure time, related to the standard ISO 5349, which in this case were based on the consumption of grinding wheels, will in most cases give a better basis for adequate risk assessment than self-exposure assessment.

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Eighty-seven workers exposed to asbestos in a railroad car repair shop, with characteristic asbestos-induced pleural plaques, underwent extensive lung-function examination. Vital capacity (VC) showed the greatest reduction among the static lung volumes, with an asymmetrical distribution of one-fourth of the subjects below 80% of the predicted value. Logistic regression demonstrated VC to be sufficient for optimal discrimination of asbestos-exposed subjects from a group of matched controls. No further discriminatory power was gained by additional spirometric measures, lung mechanics, blood gas analysis, or diffusing capacity. Smoking had an influence on dynamic but not on static lung volumes. In conclusion, reduced static lung volumes among smoking asbestos-exposed workers with pleural plaques should, in the absence of other lung diseases, be mainly attributed to the asbestos exposure.

Demonstration of increased vascular cold reactivity in patients with Raynaud's syndrome is difficult. For medico-legal reasons, it is important to get objective measures of vasospasm in these patients. Evaluation of the degree of vasospasm also provides prognostic information which is useful for patient management. In this study, we compare two methods of arterial circulation measurement. The laser Doppler scanning is a new method, which uses the recently developed laser Doppler perfusion imaging (LDPI) instrument. The aim of the present study was to compare the effect on finger skin blood flow measured with LDPI with changes in finger systolic blood pressure during local cold provocation. The effect of such provocation, skin blood flow and systolic blood pressure, were studied in 15 healthy controls. Six patients with known traumatic vasospastic disease (TVD) were also tested with both methods. Finger skin blood flow was measured with LDPI on the distal phalanx of the index finger of the left hand, every minutes during 6 min of local heating at 40 degrees C followed by local cooling for 3 min at 15 degrees C and then for 3 min at 10 degrees C. Finger systolic blood pressure was measured with strain-gauge method before and after local cooling to 10 degrees C with a cuff perfused with water of desired temperature. The test was performed in the same finger within a week of the laser Doppler scanning. Local finger cooling to 15 degrees C and 10 degrees C caused a significant decrease in blood flow, most marked at 10 degrees C. There was, however, no correlation between the decrease in blood flow and blood pressure. In the TVD-patients decreases in skin blood flow were similar compared with the healthy controls. In contrast, the changes in systolic blood pressure, were outside normal range (systolic quotient <0.65) in five of the six patients (83%), and also in 11 of the 15 healthy controls (73%). In conclusion, there is no correlation between the decrease in finger skin blood flow and systolic blood pressure during local cold provocation. For diagnosis of traumatic vasospastic disease (TVD), local cold-induced changes in finger systolic blood pressure seems superior to changes in skin blood flow, but the ideal clinical method for demonstrating increased cold-induced vasospasm is, however, still lacking.

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Increased volume of trapped gas (VTG), indicating small airways dysfunction, was found among 14 never smoking non-atopic welders who had worked for 10-31 (mean 22) years in their occupation.Spirometry and nitrogen wash out data were compared with those from a reference group of 14 never smoking men not exposed to welding. A methacholine provocation test was carried out. The effect was measured by change in forced expiratory volume in one second (FEVI) and VTG. The maximum decrease in FEV1 after inhalation of methacholine was 6% in welders and 2% among referents. Before provoca.tion VTG and VTG total lung capacity (TLC) was higher among welders (127 ml v 98 ml and 1-76% v 1-38%). The increase in VTG and VTG/TLC was higher in welders after inhalation of methacholine at concentrations of 0-001% to 2% and remained increased after inhalation of salbutamol. The differences indicate small airways disease among shipyard welders.Manual metal arc welding produces airborne particles of which 50% are in the diameter range 0 3 to 0 6 gm, thus they are respirable and likely to deposit in small airways or alveoli. Small airways are defined as airways having a diameter smaller than 2 mm.' It is suggested that small airways disease might be a forerunner of chronic obstructive lung disease.23 Because the total luminal cross section is very large in peripheral lung, small airways disease will cause no major alteration in the total airways resistance (Raw) and is not detected by methods using tests for resistance in large airways such as forced expiratory volume in one second (FEVI). Cigarette smoking may induce small airways disease in subjects with normal function in the large airways.4 Accumulation of welding particles in small airways increases production of mucus and leads to stagnation of secretion.5 Welders have been reported to have more cough, shortness of breath, and wheezing than referents.67To study small airways we measured volume of trapped gas (VTG) in the lung by using the nitrogen wash out technique.'9 In a previous study we found an increase in VTG after methacholine provocation among symptom free workers in occupational low exposure to isocyanate. " Our hypothesis was that welding fume and particles would cause small airways disease detectable by an increase in VTG. MaterialFrom the employment lists of a shipbuilding company 14 never smoking arc welders were selected by the health care nurse. Inclusion criteria for the study were: a never smoker, no previous symptoms of bronchitis, no pulmonary disease, and normal pulmonary x ray film. None of the welders had previously sought medical attention for pulmonary complaints and did not report any previous allergic symptoms. They lived in an urban area with no heavily polluted atmosphere. An indirect exposure to asbestos could not, however, be ruled out as asbestos was used for many years in the shipyard. Mean