Particulates in diesel exhaust are a substantial cause of the negative health effects traced to air pollution, above all in traffic environments. Diesel exhaust contains a number of extremely tiny particles about 1/10,000 mm in diameter, with chemical compounds bound to the surface that have been suggested to lie behind the ability of these particles to cause harmful health effects.
Individuals with lung or heart disease are especially vulnerable and are impacted most negatively during periods with high levels of air pollution. In his dissertation, Håkan Törnqvist studied the effects of diesel exhaust on healthy individuals and respective patient groups with chronic obstructive lung disease (COL) and coronary disease with atherosclerosis in the coronary artery.
The aim of the studies in the dissertation was to use controlled exposure studies to try to elucidate the mechanisms that explain why diesel exhaust particulates in polluted air cause increased morbidity in both lung and heart diseases. The studies were carried out in an exposure chamber, where the individuals were exposed for one hour to, respectively, diesel exhaust with a particulate concentration of about 300 µg/m3 and filtered air. The two exposures were in random order, so the individuals served as their own controls.
The dissertation work studied whether exposure to diesel exhaust would lead to a deterioration of the lung function and increased inflammation of the airways as measured by induced sputum (coughing samples) in patients with moderately severe but stable COL. Analysis of the cough samples could not reveal any increase in inflammation of the airways, not was there any deterioration of the lung function. Studies of the these same patients were also used to determine whether exposure to diesel exhaust can lead to increased general inflammation, can impact the capacity of the blood to coagulate, or can cause damage to the lung epithelia as measured in the blood. No general increase in blood coagulation or signs of increased inflammation in the blood could be found.
The thesis also addressed the question of whether exposure to diesel exhaust can affect the vascular function in a group of healthy individuals 2 and 6 hours after exposure. In this group exposure to diesel exhaust decreased two important and complementary blood-vessel functions: the regulation of the width of the blood vessels and the body's own ability to dissolve blood clots (fibrinolysis). What's more, the study illuminated the late course of events involved in the blood-vessel effects triggered by diesel exhaust in healthy individuals in the test. As much as 24 hours after their exposure to exhaust, the capacity of their blood vessels to expand was disturbed. Moreover there were signs of systemic inflammation, measured as an increase in inflammatory markers in the blood.
The final study in the dissertation targeted individuals with clinically fully stable coronary artery disease. The issue was whether exposure to diesel exhaust can affect the heart, decrease vessel mobility, and hamper the capacity to dissolve blood clots. A lowered capacity to dissolve blood clots was observed, together with an impaired ability of blood vessels to expand. The most important finding, however, was that after exposure to diesel exhaust patients evinced EKG signs that were consistent with a shortage of oxygen in the heart muscle. This effect was general, that is, not limited to any particular blood vessel in the heart, and it was observed despite the fact that the patients were fully stable in their coronary artery disease and were under optimal medical treatment.
The dissertation clarifies previously unknown mechanisms that can explain why air pollution in particulate form causes heart attacks, stroke, and increased mortality. It shows that diesel exhaust cause a rapid deterioration of the function of blood vessels that persists as long as 24 hours after exposure. The EKG findings in heart patients indicate acute heart effects that are consistent with increased risk of heart attack in connection with exposure to traffic.On Thursday, June 5, Håkan Törnqvist, Department of Public Health and Clinical Medicine, Lung Medicine, Umeå University, will publiscly defend his thesis titled: Respiratory and Cardiovascular Responses to Diesel Exhaust Exposure.
The defense will take place at 1.00 p.m. in Hall E06, Building 6E, Stairway R. The external examiner is Professor Joel Kaufman, University of Washington, Seattle, WA, USA.
Håkan Törnqvist can be reached at phone: +46 (0)90-785 18 23 or e-mail email@example.com
New study points the way to therapy for rare cancer that targets the young
22.11.2017 | Rockefeller University
Penn study identifies new malaria parasites in wild bonobos
21.11.2017 | University of Pennsylvania School of Medicine
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
22.11.2017 | Business and Finance
22.11.2017 | Physics and Astronomy
22.11.2017 | Physics and Astronomy