Coming theses from other universities
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Working in the Swedish ambulance service – a multifaceted picture in relation to health
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-66706
This thesis in health and care sciences focuses on factors related to working in the ambulance service and their association with health.
For patients in need of emergency medical care outside healthcare facilities, ambulance personnel are, following the dispatch centre, the first link in the chain to providing good health and care on equal terms for the entire population, in accordance with the Health and Medical Services Act. Registered nurses and emergency medical technicians in the ambulance service provide advanced prehospital care that is available around the clock. The job includes several factors that may negatively affect health, such as shift work, long work hours, heavy lifting, sedentary work, stress, and the risk of exposure to threats and violence. Previous research suggests that this occupational group may be at increased risk of cardiovascular disease, mental health issues, and musculoskeletal disorders; however, the evidence is limited.
The overall aim of this thesis was to describe and analyse work- and leisure-related factors and their association with health among ambulance personnel.
To achieve the overall aim of this thesis, four studies with quantitative designs were conducted (Papers I-IV). Ambulance personnel from an ambulance service in the south of Sweden were invited to participate. Paper I (n=106) described work-, lifestyle-, and health-related factors among ambulance personnel, using health examinations, blood samples, questionnaires, and physical capacity tests. Paper II (n=79) analysed hair cortisol levels as an indicator of long-term stress and their relationship to work factors, using hair samples and questionnaires. Paper III (n=63) described and analysed patterns of physical behaviours using accelerometry and questionnaires. Paper IV analysed blood pressure variation using ambulatory monitoring and questionnaires. Additionally, Papers I, II, and IV described and analysed differences between women and men, and Papers III and IV analysed associations with different work shifts.
The main findings in this thesis indicate that ambulance personnel were exposed to several work-related factors which could negatively impact health, such as physically demanding work, psychosocial demands (for example work stress and risk of threats and violence), and shift work. Despite this, the participants reported overall good self-rated health, high self-rated work ability, high physical capacity, a high level of physical activity during leisure time, and few other lifestyle-related risk factors. However, the findings identified a high prevalence of hypertension, elevated cholesterol levels, and high body mass index among the ambulance personnel. A larger proportion of women, compared to men, reported physically demanding work; however, women performed better in the physical capacity tests and had lower ambulatory blood pressure than men. Different shift types did not appear to affect the pattern of physical behaviours.
The findings in this thesis can be related to the World Health Organization’s (WHO) framework for healthy workplaces comprising the physical and psychosocial work environment and personal health resources. Indirectly, the thesis also relates to the fourth area, which includes interaction with the surrounding society.
In conclusion, this thesis presents a multifaceted picture in relation to health for personnel working in the Swedish ambulance service.
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Epigenetic Mechanisms underlying Alcohol Dependence and Fear Memories
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-210093
Stress is a critical factor in the onset and progression of alcohol dependence, a chronic condition characterized by loss of control over alcohol drinking. Stress is also a major risk factor for other psychiatric disorders, such as anxiety disorders. Alcohol dependence and anxiety disorders share overlapping neuroadaptations, in part mediated by epigenetic mechanisms. We have previously demonstrated that chronic alcohol exposure induces DNA hypermethylation in the dorsomedial prefrontal cortex (dmPFC) in rats. In a follow-up study, our group reported that alcohol-induced hypermethylation reduces the expression of the histone methyltransferase PRDM2, which in turn promotes stress-induced reinstatement of alcohol. These findings point to undiscovered contributions of PRDM2 to stress responses.
This thesis aimed to further understand the role of PRDM2 in stress-induced maladaptive behaviors. Study 1 showed that decreased Prdm2 expression in the dmPFC-basolateral amygdala (BLA) projection resulted in an over-consolidation of fear memory through upregulated glutamatergic signaling. Study 2 showed that decreased PRDM2 activity promotes footshock-induced relapse-like behavior in both male and female rats. Together, these findings suggest that PRDM2 may be a shared molecular substrate between alcohol dependence and anxiety disorder. Downregulation of Prdm2 in the dmPFC-BLA projection did not impact stress-induced reinstatement, while decreased Prdm2 in the dmPFC-nucleus accumbens core projection promoted reinstatement. Consistent with our preclinical findings, Study 2 also found that people with alcohol dependence exhibited reduced PRDM2 expression and increased methylation at its promoter in the prefrontal cortex. This suggests that PRDM2 and its regulatory mechanisms have a mechanistic role in stress responses, and serve as epigenetic markers for alcohol dependence across species.
In both Study 1 and Study 2, we observed a broad range of defensive behaviors in rats. Therefore, in Study 3, an ethological analysis was performed to identify multiple behaviors in response to threat-associated cues. We also assessed the utility of a machine learning pipeline to perform ethological analysis. The approach from Study 3 was implemented in Study 4, in which patterns of behaviors were characterized among rats observing a conspecific undergoing fear conditioning. Heightened fear in the observer rats associated with increased neural activation in several areas, including the dmPFC. However, the increased dmPFC activity and the heightened vicarious fear were not mediated by decreased Prdm2 expression. This suggests that direct and observational fear learning in part rely on distinct molecular mechanisms. Collectively, this thesis highlights the importance of PRDM2 and its behavioral- and circuit-specific effect in mediating fear- and alcohol-associated behaviors.
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Exploring the effects of stabilized hypochlorous acid on multi-species oral biofilms
Link: http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-72397
Periodontitis and dental caries are two of the most prevalent human diseases, affecting nearly 2 billion worldwide. Persistence is largely attributed to the formation of biofilms (plaque) by oral bacteria, which left undisturbed lead to destruction of surrounding tissues and increase the risk for secondary disease. As current treatments such as mechanical removal and adjunctive therapies can be inadequate, there is a need for new anti-plaque chemical agents. Stabilized hypochlorous acid (sHOCl) has emerged as a potential anti-biofilm agent in areas such as wound therapy but its use in treating oral diseases remains unknown. Therefore, our aim in this thesis was to assess the role of sHOCl as an antimicrobial agent for use in the oral cavity.
We found that at low concentrations, sHOCl was effective in killing bacteria within mixed-species in vitro models resembling periodontitis and dental caries. Moreover, sHOCl displayed higher antibiofilm activity compared to chlorhexidine, whilst not damaging tested oral surfaces. At sub-lethal levels, sHOCl was observed to target multiple cellular components through oxidative stress in Streptococcus biofilms. Simultaneously, work on our models revealed a possible new application of CFSE-based dyes in microscopy for the live-imaging of biofilms. In particular, multi-dye compatibility opens up the possibilities for future research employing mixed-species biofilms. Finally, our preliminary findings also indicate that sHOCl may permit a selective re-growth of biofilms following exposure.
Taken together, the results of this thesis lay the groundwork for investigations of sHOCl as an antibiofilm agent, and continue to push microbial research towardsmore relevant models.