Browsing by Subject "medicine"

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  • Schreier, Nadja K. (Helsingin yliopisto, 2014)
    Background. The environment has a major impact on human beings. Extreme environmental conditions such as hot temperatures can have huge health impacts, as shown during the heat wave in Europe that occurred during the summer 2003. The main causes of death were non-communicable diseases (NCDs) such as respiratory and cardiovascular diseases. Natural and man-made disasters can cause the collapse of health infrastructure through a combination of marked increase in demand due to injuries, diseases and increased stress levels and the physical disruption/destruction of hospital buildings, roads and transport that follows such disasters. Extreme weather events and disasters are predicted to increase in the course of the ongoing climate change. Therefore, impacts on NCDs are very likely to increase, which raises the importance of the hitherto paucity of knowledge about this research area. Aims. This study investigates the associations of weather conditions, temporal variations, in addition to the impact of a disaster, namely the bombings of Helsinki during the Second World War (WWII) on NCDs, specifically for coronary heart disease (CHD), cerebrovascular disease, type 1 diabetes mellitus (T1DM), hypertension, and obesity. Materials. Three main data sets were used for this study: 1) All fatal and non-fatal coronary events in seven cities in Finland recorded in the years 1983, 1988, and 1993 (n=9243), 2) Data that originate from the Helsinki Birth Cohort Study (HBCS) include information about birth characteristics and about life-long disease outcomes in addition to deaths of subjects born in Helsinki between 1934-1944 (n=13 039), 3) Data that originate from the DiaMond project including standardized data from 112 centers in 56 countries of all children aged between 0-14 years with diagnosis of T1DM during 1990-1999 (n=31 091) Methods. The following methods were used to achieve the specific aims: 1) Comparison of regression models with weather and temporal variation variables for the prediction of coronary events was implemented for the assessment of the influence on the case-fatality of the events, 2) Log-linear regression with Fourier terms were used to assess seasonal patterns for the incidence of childhood T1DM in different geographical locations, 3) Survival analysis and regression models were used to assess life-long health outcome due to exposure to bombings in utero, and to outdoor ambient temperature at the time of conception. Results. Influences of temperature at the time of conception for hypertension and obesity were observed. Women who were conceived during the months with the warmest mean temperatures of the time-series were found to have a significantly higher probability of developing hypertension in adult life. Furthermore, women conceived during those months with very low mean temperatures had lower BMI, lower risk of obesity and also lower fat percentage in adult life. The seasonality of the incidence of the T1DM in children was demonstrated to be a global phenomenon. In addition it was shown that the further from the equator a location is in terms of latitude the higher is the probability of that location to exhibit a seasonality pattern for T1DM. A slight positive influence for the life-long development of CHD and cerebrovascular disease was found for women who were in utero during the bombings of Helsinki in WWII. Furthermore, the case fatality of coronary events during the 1983-1993 period turned out to be negatively influenced by temporal variation. Case-fatality of CHD was higher in the December holidays and on Sundays. An attempt to predict coronary events on the basis of the weather forecast for the same study period appeared not to have any useful value. Conclusions. This study contributes to the research of the fundamentals about the influence of weather, temporal variation, and disasters on NCDs. The results showed that hypertension, obesity, T1DM, CHD, and cerebrovascular disease were particularly affected by those factors. The ongoing climate change will potentially increase the impacts on NCDs. Preparedness for these increases - including the prevention of disease and the prevention of the further exacerbation of a disease – is an important task for the near future. Further, the collection of data in developing countries where data are sparse needs close collaboration between interdisciplinary scientific teams in order to address the complexity of this type of research and to contribute to the preparedness of health authorities in such challenging regions.
  • Leskinen, Katarzyna (Helsingin yliopisto, 2016)
    Y. enterocolitica is a human pathogen that cause mostly food-borne yersiniosis, usually a diarrheal disease sometimes followed by post-infectious reactive arthritis. Yersiniosis is considered to be the third most common cause of gastroenteritis in Europe. In Finland both Y. pseudotuberculosis and Y. enterocolitica cause hundreds of human infections annually. The aim of the study is to characterize the intricate regulatory networks of Yersinia especially those that control the expression of the virulence factors. To achieve that goal three regulators (YbeY, RfaH and Hfq) were initially selected. The absence of ybeY gene in Y. enterocolitica serotype O:3 resulted in misprocessing of 16S rRNA, severe decrease of growth rate, disturbed regulation of the Yersinia virulence plasmid genes expression and affected the expression of small RNAs. Furthermore, the ybeY mutant displayed impairment of many virulence-related features, and decreased infectivity in the cell infection model. The study revealed that RfaH of Y. enterocolitica O:3 acts as a highly specific regulator that enhances the transcription of selected operons involved in biosynthesis of lipopolysaccharide. Furthermore, the transcriptomics study indicated that some changes seen in the rfaH mutant strain were actually due to indirect responses to the loss of O-antigen. Moreover, the lack of RfaH resulted in attenuated stress response and lower resistance to selected chemical compounds. The loss of Hfq caused impairment in growth, elongation of the bacterial cells, and decreased the resistance of bacteria to heat, acid and oxidative stresses, as well as attenuation in mouse infection experiments. Moreover, this study revealed that several alterations typical for the hfq-negative phenotype were due to derepression of the transcriptional factor RovM. In conclusion, all the studied mutations caused different alterations in gene regulatory networks and eventually led to a compromise in the virulence of Y. enterocolitica O:3. The studied mutants showed significant decrease in resistance to different environmental conditions and alterations in the bacterial physiology that contribute to vitality and ability to establish infection in host organism.