Grinding dusts of alloyed steel and hard metal.
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Biomedical subjects
Publications and source records attributed to M Koponen.
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A daily dose of papaverine (5--10 mg per kg body weight) was administered on a double-blind basis for two months to 42 successive child patients suffering from migraine or other vascular headache attacks not less than twice a month. Thirty-seven patients received the drug for the whole period of two months and 31 of these could be followed for a period of one to 10 months (mean 4.5 months) after the cessation of the treatment. Nineteen received papaverine and 18 placebo. Six out of 19 papaverine patients and none of 18 placebo patients were completely free from attacks during the treatment. Altogether 11 patients in the papaverine group and 5 in the placebo group experienced a 75--100% reduction in attack frequency which was accompanied by lower intensity and shorter duration of attacks. The results were best in cases with classical migraine. An "excellent" or "good" drug effect was experienced by 58% of papaverine patients and 17% of placebo patients.
The amount and distribution of the welding fume lung contaminants was measured in 44 arc welders from two shipyards. The measurement was made from the determination of the permanent field after the subject was magnetized in a low external magnetic field, the values being used for the calculation of the amount of contaminants in the lungs. Less than 4 mg of dust was found in the lungs of nonexposed controls. In the shipyard welder's lungs, after two years of exposure, on the average 7 mg (range 4-15) of welding dust was observed. After a continuous exposure of about 18 years the amounts were 200 mg (range 30-1,500) in shipyard A and 700 mg (150-2,000) in shipyard B, respectively. On the basis of data obtained from retired welders, the clearance rate of 45% in welders from shipyard A and 18% in shipyard B were calculated, the latter figure being probably more accurate. The distribution of contaminants was 52% in the right and 48% in the left lung. The radiological findings correlated well with the amounts of welding fume contaminants measured with the magnetic method.
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The dust concentrations of different work phases in iron foundries of different sizes were studied. The results of the total dust measurements made during the Finnish Foundry Project were considered according to the eight main work phases, and the 51 iron foundries were divided into four groups according to the number of foundry workers. The division between the groups at 25, 50, and 100 workers is related to the degree of mechanization in Finnish foundries. The total dust concentration clearly increased in sand making and melting as the size of the foundry increased. The concentration decreased in molding, coremaking, knock-out, and cleaning as the number of workers increased. No significant differences between the foundry groups could be found during casting. The factors affecting the differences in dust concentrations are discussed.
Dust measurements were made in 51 iron, 9 steel, and 8 nonferrous foundries, at which 4,316 foundrymen were working. The sampling lasted at least two entire shifts or work days continuously during various operations in each foundry. The dust samples were collected at fixed sites or in the breathing zones of the workers. The mass concentration was determined by weighing and the respirable dust fraction was separated by liquid sedimentation. The free silica content was determined by X-ray diffraction. In the study a total of 3,188 samples were collected in the foundries and 6,505 determinations were made in the laboratory. The results indicated a definite difference in the dust exposure during various operations. The highest dust exposures were found during furnace, cupola, and pouring ladle repair. During cleaning work, sand mixing, and shake-out operations excessive silica dust concentrations were also measured. The lowest dust concentrations were measured during melting and pouring operations. Moderate dust concentrations were measured during coremaking and molding operations. The results obtained during the same operations of iron and steel foundries were similar. The distribution of the workers into various exposure categories, the content of respirable dust and quartz, the correlation between respirable dust and total dust, and the correlation between respirable silica and total dust concentrations are discussed. Observations concerning dust suppression and control methods are briefly considered.
A simple test system for comparing the proliferation inhibition properties of cyclosporins (Cs) on susceptible T cells is described. This test was applied to a number of natural and chemically altered Cs-compounds, the latter from inactive, hypo-active and hyper-active Cs. These cyclosporins constituted standards for further comparison of the activities of new Cs such as fluorescent derivatives of the molecules, and especially for determining their mechanism of action. The use of Cs-sensitive (CsS) and Cs-resistant (CsR) cell lines permitted the distinction between specific cytostatic and generalized cytotoxic effects. Active--but not inactive--Cs were found to cause the appearance of refractive globular bodies in both CsS and CrR lymphocytes and in macrophages. When active fluorescent Cs were used, Cs detectable by fluorescence after one or several days was found to be concentrated within these globular bodies.
Cyclosporin (Cs)-binding sites on murine spleen lymphocytes and on Cs-sensitive (CsS) and Cs-resistant (CsR) cloned lymphoma lines were compared using a ditritiated derivative of cyclosporin C (d3H-CsC). All three types of lymphocytes displayed similar d3H-CsC-binding characteristics. There were no major differences in the d3H-CsC-binding sites in terms of their cell surface density (number per surface area), their affinity and their specificity (capacity to discriminate between different Cs forms). The presence of the presumably membranous Cs-binding site is therefore insufficient to confer susceptibility to Cs, and resistance can thus be obtained at a post-receptor level. With the CsS clone, there was a general correlation between the Cs-specific binding capacity and the Cs-specific biological activity inasmuch as Cs which were weakly or not at all cytostatic bound only very poorly to the d3H-CsC-binding site. Such a correlation could not be established in the case of a mixed spleen cell population; which implies that, in such a system, Cs processing might play a role in its activity. Binding to the receptor may be an early but only a permissive step in the mechanism of action of Cs.