The effects of sound level and vibration magnitude on the relative discomfort of noise and vibration

The relative discomfort caused by noise and vibration, how this depends on the level of noise and the magnitude of vibration, and whether the noise and vibration are presented simultaneously or sequentially has been investigated in a laboratory study with 20 subjects. Noise and vertical vibration were reproduced with all 49 combinations of 7 levels of noise and 7 magnitudes of vibration to allow the discomfort caused by one of the stimuli to be judged relative to the other stimulus using magnitude estimation. In four sessions, subjects judged noise relative to vibration and vibration relative to noise, with both simultaneous and sequential presentations of the stimuli. The equivalence of noise and vibration was not greatly dependent on whether the stimuli were simultaneous or sequential, but highly dependent on whether noise was judged relative to vibration or vibration was judged relative to noise. When judging noise, higher magnitude vibrations appeared to mask the discomfort caused by low levels of noise. When judging vibration, higher level noises appeared to mask the discomfort caused by low magnitudes of vibration. The judgment of vibration discomfort was more influenced by noise than the judgment of noise discomfort was influenced by vibration

Estudo dos efeitos auditivos e extra-auditivos da exposição ocupacional a ruído e vibração Auditory and extra-auditory effects of occupational exposure to noise and vibration

Objetivo: Este estudo teve como objetivo investigar as queixas de saúde e achados audiológicos de dois grupos de trabalhadores. Forma de estudo: Clínico prospectivo randomizado. Material e método: Grupo 1- exposto a níveis de pressão sonora elevados e vibração transmitida por meio das mãos-braços nos trabalhadores que operam motorroçadeiras, e Grupo 2- exposto a níveis elevados de pressão sonora e vibração transmitida por meio do corpo inteiro nos trabalhadores que operam equipamentos pesados como pá-carregadeira, moto niveladora, retro-escavadeira e rolo compressor. Os 73 participantes passaram por entrevista, inspeção do meato acústico externo e audiometria tonal. Resultado: Em relação aos problemas de saúde, o grupo 2, exposto a vibração de corpo inteiro, é o que apresenta um maior número de queixas. Os trabalhadores do Grupo 1, sem exceção, fazem uso do protetor auditivo e apenas 4 (11%) referem zumbido. No Grupo 2 nem todos os trabalhadores usam o protetor auditivo e 6 (17%) referem apresentar zumbido. Entretanto, a porcentagem de audiogramas alterados é mais elevada no grupo 1, expostos a vibração transmitida por meio das mãos-braços. Conclusão: Este estudo revelou uma série de deficiências no acompanhamento de saúde dessas populações e demonstrou a necessidade da implantação de programas preventivos tanto no que se refere à exposição a níveis de pressão sonora elevados quanto à vibração.<br>Aim: The present study aimed to investigate the health complaints and the audiological findings of 2 groups of workers. Study design: Clinical prospective randomized. Material and method: Group 1 was exposed to high sound pressure levels and vibration transmitted by hands and arms through the use of power brush cutter/string trimmers. Group 2 was exposed to high sound pressure levels and whole-body vibration transmitted by heavy machinery such as vibrating compactor rollers, skid-steer loaders, backhoes and compact hydraulic excavators. The 73 participants underwent an interview, otoscopy, and pure-tone audiometry. Regarding general health, group 2 workers, exposed to whole-body vibration presented the highest number of complaints. Results: All the participants from group 1 use hearing protectors and 11% of them complained about tinnitus. Not all workers from group 2 use hearing protectors and 17% of them 2 reported tinnitus. However, group 1 workers, exposed to hand-arm vibration was the group with the highest percentage of abnormal audiograms. Conclusion: This study revealed a series of weaknesses in the health surveillance of these populations and indicated the need for the implementation of preventive programs focusing on their exposures to noise and vibration

Circulating heat shock protein 70 (HSPA1A) in normal and pathological pregnancies

Heat shock proteins (Hsps) are ubiquitous and phylogenetically conserved molecules. They are usually considered to be intracellular proteins with molecular chaperone and cytoprotective functions. However, Hsp70 (HSPA1A) is present in the peripheral circulation of healthy nonpregnant and pregnant individuals. In normal pregnancy, circulating Hsp70 levels are decreased, and show a positive correlation with gestational age and an inverse correlation with maternal age. The capacity of extracellular Hsp70 to elicit innate and adaptive proinflammatory (Th1-type) immune responses might be harmful in pregnancy and may lead to the maternal immune rejection of the fetus. Decreased circulating Hsp70 level, consequently, may promote the maintenance of immunological tolerance to the fetus. Indeed, elevated circulating Hsp70 concentrations are associated with an increased risk of several pregnancy complications. Elevated Hsp70 levels in healthy pregnant women at term might also have an effect on the onset of labor. In preeclampsia, serum Hsp70 levels are increased, and reflect systemic inflammation, oxidative stress and hepatocellular injury. Furthermore, serum Hsp70 levels are significantly higher in patients with the syndrome of hemolysis, elevated liver enzymes, and low platelet count (HELLP syndrome) than in severely preeclamptic patients without HELLP syndrome. In HELLP syndrome, elevated serum Hsp70 level indicates tissue damage (hemolysis and hepatocellular injury) and disease severity. Increased circulating Hsp70 level may not only be a marker of these conditions, but might also play a role in their pathogenesis. Extracellular Hsp70 derived from stressed and damaged, necrotic cells can elicit a proinflammatory (Th1) immune response, which might be involved in the development of the maternal systemic inflammatory response and resultant endothelial damage in preeclampsia and HELLP syndrome. Circulating Hsp70 level is also elevated in preterm delivery high-risk patients, particularly in treatment-resistant cases, and may be a useful marker for evaluating the curative effects of treatment for preterm delivery. In addition, increased circulating Hsp70 levels observed in asthmatic pregnant patients might play a connecting role in the pathomechanism of asthmatic inflammation and obstetrical/perinatal complications. Nevertheless, a prospective study should be undertaken to determine whether elevated serum Hsp70 level precedes the development of any pregnancy complication, and thus can help to predict adverse maternal or perinatal pregnancy outcome. Moreover, the role of circulating Hsp70 in normal and pathological pregnancies is not fully known, and further studies are warranted to address this important issue