| 11. |
- Andersson, Bengt-Åke
(författare)
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Circulating Biomarkers in Patients with Head and Neck Cancer and the Influence of Cigarette Smoking
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Head and neck cancer (HNC) is a collective name for heterogeneous tumors located in the head and neck regions for which smoking, alcohol and human papillomavirus (HPV) are documented risk factors. The survival of HNC patients has only improved marginally during the last decade. The most important prognostic factors are tumor size, local spread and distant metastases, tumor node metastasis (TNM) staging. Prognostic biomarkers are needed as a complement to TNM staging.The aim for this thesis was to investigate rapid and low cost blood based biomarkers which could indicate the risk of HNC, recurrence of the disease or the survival of HNC patients. Furthermore, the aim was to examine how cigarette smoking influences the levels of biomarkers.In paper I, a possible role of plasma cytokines or proteins associated with immune response or inflammation, as biomarkers for the survival of HNC patients was investigated. Higher levels of C-reactive protein (CRP) and tumor necrosis factor alpha (TNF-α) were detected in plasma of the patients compared with the levels in the controls. The elevated levels of these two biomarkers detected in patients were associated with decreased survival.In paper II, the influence of 45 single nucleotide polymorphisms (SNPs) located in 41 genes associated with cell cycle progression, cell death, DNA repair or immune response on cancer risk, tumor recurrence and survival in HNC patients were investigated. SNPs in immune response genes were associated with risk for HNC, an elevated risk for recurrence and a decreased survival in HNC patients.In paper III, the influence of cigarette smoking on levels of inflammatory cells, proteins or cytokines/chemokines, microRNAs (miRNAs) and SNPs was analysed in healthy smokers and non-smokers. Higher levels of total white blood cells (WBCs), neutrophils, monocytes, lymphocytes, neutrophil to lymphocyte ratio (NLR), CRP, monocyte chemoattractant protein- 1 (MCP-1) and interferon gamma (IFN-γ) were detected in smokers compared to non-smokers and indicate an inflammatory response. Also, a lower level of oncomiRNA miR-21was detected in smokers. This alteration, in combination with the elevated levels of IFN-γ in smokers could be a protective response to cigarette smoke. The higher levels of IFN-γ in smokers compared to non-smokers were however only detected in individuals with SNP rs2069705 genotype AG/GG. This indicates a genetic association of the levels of IFN-γ.In paper IV, the separate effects of cigarette smoking and HNC on inflammatory or immune biomarkers and the impact of high risk human papillomavirus, age and gender were investigated. Comparisons of circulating levels of WBCs and its subpopulations, plasma proteins or cytokines/chemokines between smoking and non-smoking patients, smoking and non-smoking controls and between the patient and control groups were analysed. Smoking had highest impact on elevated levels of WBCs, IFN-γ and MCP-1, and HNC had highest impact on elevated levels of neutrophils, monocytes, NLR, CRP, macrophage inflammatory protein 1 beta and TNF-α.In conclusion, host immune response associated parameters could be suitable as biomarkers for the risk of HNC, risk of recurrence or in predicting survival of HNC patients. This thesis show that HNC are associated with systemic inflammatory response and upregulated CRP and TNF-α is related to shorter survival in HNC patients. Additionally, SNPs in immune response genes such as rs1800629 in the TNF-α gene indicates a risk for HNC or an elevated risk for recurrence and a decreased survival in HNC patients. These rapid and low cost blood based biomarkers could be used in combination or as a supplement to established biomarkers in the clinic for a more personalized treatment modality.
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| 12. |
- Andreae, Christina, 1969-
(författare)
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Appetite in patients with heart failure : Assessment, prevalence and related factors
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Appetite is an important component in nutrition for maintaining the food intake needed by the body. Decreased appetite is a common clinical problem in patients with heart failure. It has a negative impact on food intake and possibly on malnutrition and health outcomes. There is a lack of evidence on how to assess appetite in heart failure. Furthermore, there are knowledge gaps about factors associated with appetite and which role appetite plays for health status in heart failure. Aim: The overall aim of the thesis was to investigate appetite in patients with heart failure. Four studies were conducted with the goal to evaluate the psychometric properties of the Council on Nutrition Appetite Questionnaire (CNAQ) (I) and to explore the prevalence of decreased appetite and related factors associated with appetite in patients with heart failure (II-IV). Methods: A multicenter study was conducted in three outpatient heart failure clinics in the center of Sweden during 2009-2012. Data were collected through a baseline measurement (I-IV) and an 18-month follow-up (IV). The first study was a psychometric evaluation study (I), while the other studies had an observational cross-sectional design (II-III) and an observational prospective design (IV). One hundred and eighty-six patients diagnosed with heart failure and experiencing heart failure symptoms participated at baseline. At the 18-month follow-up study (IV), one hundred and sixteen participants from the baseline participated. Data were collected from medical records (pharmacological treatment, comorbidity, left ventricle ejection fraction, time of diagnosis), self-reported questionnaires (demographic background data, appetite, symptoms of depression, health status, sleep, self-reported physical activity), objective measurements (anthropometric assessment of body size, blood samples, six minutes’ walk test, and physical activity measured with an actigraph) and clinical assessment (New York Heart Association (NYHA) functional classification, and cognitive assessment). The main outcome variables included appetite (I, II and IV) and health status (III). Descriptive and inferential statistics were used in the studies (I-IV). Results: The majority of the participants had moderate heart failure symptoms, i.e., NYHA class II (n=114, 61%). Most of the participants were men (n=130, 70%). Mean age was 70,7 years, (SD=11,0), and mean BMI was 28.7 (SD=5.3). The CNAQ showed acceptable psychometric properties for assessing appetite in patients with heart failure (I). This thesis shows that 38% of the participants experienced an appetite level that put them at risk of weight loss (I). It was shown that factors such as biological, medical, psychological (II) and physical activity/exercise capacity (IV) are associated with appetite. Also, appetite was associated with impaired health status. However, this association was found to be moderated by symptoms of depression (III). Neither appetite nor physical activity changed during the 18-month follow-up (IV). Conclusion: Decreased appetite is a serious phenomenon that needs attention in the care of patients with heart failure. Health care professionals can now use a validated and simple appetite instrument to assess appetite in heart failure. In addition, attention should be paid to elderly patients and those who have symptoms of depression, sleep problems, impaired cognitive function and impaired physical activity, as well as to patients on suboptimal medical treatment. Higher appetite was shown to contribute to a better health status, but this was only evident in patients without symptoms of depression. Therefore, special attention should be paid to symptoms of depression, as this risk factor affected the association between appetite and health status. This thesis enhances the understanding of the magnitude of the problem with decreased appetite in heart failure both in numbers and factors. New priorities in nutrition care and new ideas can be established, both in practice and in research, in order to improve a nutrition care that is vital for patients with heart failure.
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| 13. |
- Aronsson, Mattias, 1989-
(författare)
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Health Economic Evaluations of Screening Programs - Applications and Method Improvements
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Screening to detect diseases early is attractive as it can improve the prognosis and decrease costs, but it is often a problematic concept and there are several pitfalls. Many healthy individuals have to be investigated to avoid a disease in a few, which results in a dilemma because to save a few, many are exposed to a procedure that could potentially harm them. Other examples of problems associated with screening are latent diseases and over-treating. The question of optimal design of a screening program is another source of uncertainty for decision-makers, as a screening program may potentially be implemented in very different ways. This highlights the need for structured analyses that weigh benefits against the harms and costs that occur as consequences of the screening.The aim of this thesis is, therefore, to explore, develop and implement methods for health economic evaluations of screening programs. This is done to identify problems and suggest solutions to improve future evaluations and in extension policy making.This aim was analysed using decision analytic cost-effectiveness analyses constructed as Markov models. These are well-suited for this task given the sequential management approach where all relevant data are unlikely to come from a single source of evidence. The input data were in this thesis obtained from the published literature and were complemented with data from Swedish registries and the included case studies. The case studies were two different types of screening programs; a program of screening for unknown atrial fibrillation and a program to detect colorectal cancer early. Further, the implementation of treatment with thrombectomy and novel oral anticoagulants were used to illustrate how factors outside the screening program itself have an impact on the evaluations.As shown by the result of the performed analyses, the major contribution of this thesis was that it provided a simple and systematic approach for the economic evaluation of multiple screening designs to identify an optimal design.In both the included case studies, the screening was considered costeffective in detecting the disease; unknown atrial fibrillation and colorectal cancer, respectively. Further, the optimal way to implement these screening programs is dependent on the threshold value for cost-effectiveness in the health care sector and the characteristics of the investigated cohort. This is because it is possible to gain increasingly more health benefits by changing the design of the screening program, but that the change in design also results in higher marginal costs. Additionally, changes in the screening setting were shown to be important as they affect the cost-effectiveness of the screening. This implies that flexible modelling with continuously updated models are necessary for an optimal resource allocation.
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| 14. |
- Atikuzzaman, Mohammad, 1977-
(författare)
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Seminal Influence on the Oviduct : Mating and/or semen components induce gene expression changes in the pre-ovulatory functional sperm reservoir in poultry and pigs
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Internal fertilization occurs in birds and eutherian mammals. Foetal development, however, is either extra- respectively intra-corpore (egg vs uterus). In these animal classes, the female genital tract stores ejaculated spermatozoa into a restricted oviductal segment; the functional pre-ovulatory sperm reservoir, where they survive until ovulation/s occur. Paradoxically, this immunologically foreign sperm suspension in seminal fluid/plasma, often microbiologically contaminated, ought to be promptly eliminated by the female local immune defence which, instead, tolerates its presence. The female immune tolerance is presumably signalled via a biochemical interplay of spermatozoa, as well as the peptides and proteins of the extracellular seminal fluid, with female epithelial and immune cells. Such interplay can result in gene expression shifts in the sperm reservoir in relation to variations in fertility. To further aid our understanding of the underlying mechanisms, this thesis studied the proteome of the seminal fluid (using 2D SDS-PAGE and mass spectrometry) including cytokine content (using Luminex and/or ELISA) of healthy, sexually mature and fertile boars and cocks. As well, gene expression changes (using cDNA microarray) in the oviductal sperm reservoirs of sexually-mature females, mated or artificially infused with homologous sperm-free seminal fluid/plasma were studied. Pigs were of commercial, fertility-selected modern breeds (Landrace), while chicken belonged to the ancestor Red Junglefowl (RJF, low egg laying-capacity), a selected egg-layer White Leghorn (WL) and of their Advanced Intercross Line (AIL). Ejaculates were manually collected as single sample in cocks or as the sperm-rich fraction [SRF] and the post- SRF fraction in boars to harvest seminal fluid/plasma for proteome/cytokine and infusion-studies. Oviducts were retrieved for gene-expression analyses via microarray immediately post-mortem (chicken) or at surgery (pig), 24 h after mating or genital infusion. In pigs, the protein-rich seminal plasma showed the highest amounts of cytokines [interferon-γ, interferon gamma-induced protein 10 (IP-10/CXCL10), macrophage derived chemokine (MDC/CCL22), growth-regulated oncogene (GRO/CXCL1), granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemo-attractant protein-1 (MCP-1/ CCL2), interleukin (IL)-6, IL-8/CXCL8, IL-10, IL-15, IL-17 and transforming growth factor (TGF)-β1-3) in the larger, protein-rich and sperm-poor post-SRF, indicating its main immune signalling influence. Chicken showed also a plethora of seminal fluid proteins with serum albumin and ovotransferrin being conserved through selection/evolution. However, they showed fewer cytokines than pigs, as the anti-inflammatory/immune-modulatory TGF-β2 or the pro-inflammatory CXCL10. The RJF contained fewer immune system process proteins and lacked TGF-β2 compared to WL and AIL, suggesting selection for increased fertility could be associated with higher expression of immune-regulating peptides/proteins. The oviductal sperm reservoir reacted in vivo to semen exposure. In chicken, mating significantly changed the expression of immune-modulatory and pH-regulatory genes in AIL. Moreover, modern fertile pigs (Landrace) and chicken (WL), albeit being taxonomically distant, shared gene functions for preservation of viable sperm in the oviduct. Mating or SP/SF-infusion were able to change the expression of comparable genes involved in pH-regulation (SLC16A2, SLC4A9, SLC13A1, SLC35F1, ATP8B3, ATP13A3) or immune-modulation (IFIT5, IFI16, MMP27, ADAMTS3, MMP3, MMP12). The results of the thesis demonstrate that both mating and components of the sperm-free seminal fluid/plasma elicit gene expression changes in the pre-ovulatory female sperm reservoir of chickens and pigs, some conserved over domestication and fertility-selection.
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| 15. |
- Axelsson, Daniel, 1974-
(författare)
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Postpartum infections; prevalence, associated obstetric factors and the role of vitamin D
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Postpartum infections are a major cause of maternal mortality and morbidity worldwide. Breast infection, endometritis, urinary tract infection and wound infections are the most common postpartum infections and together they affect almost 20% of women after childbirth. Some risk factors for postpartum infections, for example cesarean section, have been relatively well studied, but other presumable risk factors are yet to be confirmed.The proportion of pregnant women who are overweight or obese is increasing in most parts of the world. Increased maternal body mass index (BMI) is associated with maternal and infant morbidity. The association between overweight / obesity and postpartum infections is incompletely understood. Vitamin D deficiency has in epidemiological studies been shown to increase the risk of various infections. Furthermore, vitamin D is an important factor in the human immune system. Concomitantly, vitamin D supplementation seems protective against some types of infections. Whether vitamin D deficiency is a risk factor for postpartum infections has not been studied.Material and Methods: In a population-based observational study using questionnaires, the prevalences of postpartum wound infections, endometritis, urinary tract infections and mastitis in the southeast region of Sweden were estimated (Paper I). All women giving birth in the region during one year (n=11 124) were asked to participate. Papers II and III were cohort studies based on all deliveries in Sweden during eight years (2005-2012). Data sources were the Swedish Medical Birth Register, the Swedish National Patient Register and the Swedish Prescribed Drugs Register. In paper II all term deliveries were included (n=795 072). Risk factors for postpartum wound infections, endometritis and urinary tract infection were evaluated. Paper III included all deliveries (n=841 780) and examined the impact of BMI on the risk of postpartum wound infections, endometritis and breast abscess after different modes of delivery. Infections were defined as the presence of applicable ICD-10 codes. The Mantel-Haenszel technique was used to calculate adjusted odds ratios. In paper IV the association between vitamin D deficiency and overall postpartum infectious morbidity was analyzed. Serum samples from the Pregnancy Biobank in Linköping, drawn at the time of delivery, were used to determine concentrations of 25-hydroxyvitamin D in 1397 women. ICD-10 codes were extracted from the women’s medical records. The prevalence of vitamin D deficiency was calculated and adjusted odds ratios for postpartum infections were estimated with multivariable logistic regression analysis.Results: More than one out of ten women in southeast Sweden reported wound infections; endometritis, urinary tract infection or mastitis postpartum and 7.5% reported antibiotic treatment for infection. Cesarean section was the strongest risk factor for wound infection, followed by obstetric anal sphincter injuries and episiotomy. For endometritis, the strongest risk factors were anemia, manual placental removal and emergency cesarean section. Urinary tract infection was associated with anemia, instrumental vaginal delivery and emergency cesarean section. There was a dose-dependent increased risk of postpartum infection with higher BMI. For morbidly obese women the risk of infection was over 50% higher than for normal weight women. The risk of endometritis after normal vaginal delivery increased the higher the BMI, as did the risk of wound infection after cesarean section, regardless of the type of cesarean section. For breast abscess, there was an inverse association with BMI.Vitamin D deficiency was present among almost 60% of pregnant women at the time of delivery. No association between vitamin D deficiency and postpartum infections was found.Conclusions: Every tenth Swedish woman acquired an infection postpartum and three quarters of them received antibiotics for infection. Anemia was an important risk factor for postpartum infection, and the strongest risk factor for endometritis and urinary tract infection. Strong efforts should be made to reduce blood loss during and after childbirth. This thesis confirmed cesarean section as a major risk factor for postpartum infection, especially wound infection. The risk increased if the woman was overweight or obese, regardless of whether it was a planned or an emergency cesarean section.Vitamin D deficiency was common among Swedish pregnant women, but it was not found to be associated with postpartum infections.
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| 16. |
- Aziz, Abdul Maruf Asif
(författare)
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Neuropeptide Receptors as Treatment Targets in Alcohol Use Disorders
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Alcohol use disorder (AUD) is a complex disorder with multiple pathophysiological processes contributing to the initiation, progression and development of the disease state. AUD is a chronic relapsing disease with escalation of alcohol-intake over time in repeated cycles of tolerance, abstinence and relapse and hence, it is very difficult to treat. There are only a few currently available treatments with narrow efficacy and variable patient response. Thus it is important to find new, more effective medications to increase the number of patients who can benefit from pharmacological treatment of AUD.The research presented in this thesis work focuses on the critical involvement of central neuropeptides in alcohol-related behaviors. The overall aim was to evaluate the nociceptin/orphanin FQ (NOP) receptor, the neuropeptide Y (NPY) Y2 receptor and the melanin-concentrating hormone (MCH) receptor 1 as novel and potential pharmacological treatment targets for AUD by testing the NOP receptor agonist SR-8993, the NPY-Y2 receptor antagonist CYM-9840 and the MCH1 receptor antagonist GW803430 in established animal models.In the first study (Paper I), the novel and selective NOP agonist SR-8993 was assessed in rat models of motivation to obtain alcohol and relapse to alcohol seeking behavior using the operant self-administration (SA) paradigm. Firstly, treatment with SR-8993 (1 mg/kg) showed a mildly anxiolytic effect and reversed acute alcohol withdrawal-induced “hangover” anxiety in the elevated plus-maze (EPM). Next, it potently attenuated alcohol SA and motivation to obtain alcohol in the progressive ratio responding (PRR) and reduced both alcohol cue-induced and yohimbine stress-induced reinstatement of alcohol seeking, without affecting the pharmacology and metabolism of alcohol nor other control behaviors. To extend these findings, SR-8993 was evaluated in escalated alcohol-intake in rats. Treatment with SR-8993 significantly suppressed alcohol-intake and preference in rats that were trained to consume high amounts of alcohol in the two-bottle free choice intermittent access (IA) paradigm. SR-8993 also blocked operant SA of alcohol in rats that showed robust escalation in operant alcohol SA following chronic IA exposure to alcohol.In the second study (Paper II), SR-8993 was further evaluated in a model for escalated alcohol-intake induced by long-term IA exposure to alcohol. The effect of previous experience on operant alcohol SA on two-bottle free choice preference drinking was evaluated and sensitivity to treatment with SR-8993 was tested in rats selected for escalated and non-escalated alcohol seeking behavior. We found that rats exposed to the combined SA-IA paradigm showed greater sensitivity to SR-8993 treatment. In addition, acute escalation of alcohol SA after a three-week period of abstinence was completely abolished by pretreatment with SR-8993.In the third study (Paper III), the effects of the novel, small molecule NPY-Y2 antagonist CYM-9840 were tested in operant alcohol SA, PRR which is a model for motivation to work for alcohol and reinstatement of alcohol-seeking behavior. Treatment with CYM-9840 (10 mg/kg) potently attenuated alcohol SA, progressive ratio responding and stress-induced reinstatement using yohimbine as the stressor, while alcohol cue-induced reinstatement was unaffected. Moreover, a range of control behaviors including taste sensitivity, locomotor and pharmacological sensitivity to the sedative effects of alcohol remained unaffected by CYM-9840 pretreatment, indicating that its effects are specific to the rewarding and motivational aspects of alcohol-intake and related behaviors. CYM-9840 also reversed acute alcohol withdrawal-induced “hangover” anxiety measured in the EPM and reduced alcohol-intake in the 4 hour limited access two-bottle free choice preference drinking model.Finally, in the fourth study (Paper IV), the selective MCH1-R antagonist GW803430 was tested in rat models of escalated alcohol-intake. Pretreatment with GW803430 (effective at 10 & 30 mg/kg) dose-dependently reduced alcohol and food-intake in rats that consumed high amounts of alcohol during IA, while it only decreased food-intake in rats that consumed low amounts of alcohol during IA, likely due to a floor effect. Upon protracted abstinence following IA, GW803430 significantly reduced operant alcohol SA and this was associated with adaptations in MCH and MCH1-R gene-expression. In contrast, GW803430 did not affect escalated alcohol SA induced by chronic alcohol vapor exposure and this was accompanied by no change in MCH or MCH1-R gene expression. Overall, these results suggest that the MCH1-R antagonist affects alcohol-intake through regulation of both motivation for caloric-intake and the rewarding properties of alcohol.In conclusion, our results suggest critical roles for these central neuropeptides in the regulation of anxiety and of alcohol reward, making them potential pharmacological targets in the treatment of AUD.
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| 17. |
- Bahlmann, Hans, 1973-
(författare)
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Goal-directed fluid therapy during major abdominal surgery
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Both hypo- and hypervolemia increase the risk for postoperative complications after major abdominal surgery. Fluid needs vary amongst patients depending on differences in preoperative dehydration, intraoperative physiology and surgical characteristics. Goal-directed fluid therapy (GDFT) aims to target the right amount of fluid administration in each patient by evaluating the effect of fluid boluses on haemodynamic parameters such as stroke volume. It has been shown to reduce postoperative morbidity and is generally recommended for high-risk surgery. The overall aim of this thesis was to evaluate whether more simple devices for GDFT result in clinical benefit, thus facilitating the application of GDFT in more patients.Aim: To compare performance and clinical benefit of pleth variability index (PVI), a noninvasive, easy-to-use device for GDFT, with the reference method of oesophageal Doppler; to evaluate methods for measuring preoperative dehydration and its effect on fluid handling by the body; and to confirm the expected clinical benefits of GDFT in patients undergoing oesophageal resection, a high risk procedure.Methods: In Studies I-III 150 patients scheduled for open abdominal surgery of at least 2 hrs were randomised to GDFT with either PVI or oesophageal Doppler. In the first half of the cohort, both monitors were connected to compare intraoperative performance. In 30 patients preoperative dehydration was analysed. In study IV 64 patients undergoing oesophageal resection were randomised to GDFT using pulse contour analysis or standard treatment.Results: The concordance between PVI and oesophageal Doppler for indicating the need for and effect of a fluid bolus was low, and both had only limited capacity to predict the effect of a fluid bolus. Both methods resulted in comparable amounts of fluid being administered and similar clinical outcome. Preoperative dehydration was limited but did impact on fluid handling. Patients receiving GDFT during oesophageal resection received more fluid and more dobutamine compared to controls, but this did not result in any clinical benefit.Conclusions: There are methodological issues as well as uncertainties about the clinical benefit of GDFT. We cannot recommend a strict application of any GDFT strategy, but suggest that its components should be incorporated in a more encompassing assessment of a patient’s fluid needs. The measurement, impact and treatment of preoperative dehydration need to be further clarified.
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| 18. |
- Bahrampour, Shahrzad
(författare)
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Genetic mechanisms regulating proliferation and cell specification in the Drosophila embryonic CNS
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The central nervous system (CNS) consists of an enormous number of cells, and large cellular variance, integrated into an elaborate network. The CNS is the most complex animal organ, and therefore its establishment must be controlled by many different genetic programs. Considering the high level of complexity in the human CNS, addressing issues related to human neurodevelopment represents a major challenge. Since comparative studies have revealed that neurodevelopmental programs are well conserved through evolution, on both the genetic and functional levels, studies on invertebrate neurodevelopmental programs are often translatable to vertebrates. Indeed, the basis of our current knowledge about vertebrate CNS development has been greatly aided by studies on invertebrates, and in particular on the Drosophila melanogaster (fruit fly) model system.This thesis attempted to identify novel genes regulating neural cell specification and proliferation in the CNS, using the Drosophila model system. Moreover, I aimed to address how those genes govern neural progenitor cells (neuroblasts; NBs) to obtain/maintain their stemness identity and proliferation capacity, and how they drive NBs through temporal windows and series of programmed asymmetric division, which gradually reduces their stemness identity in favor of neural differentiation, resulting in appropriate lineage progression. In the first project, we conducted a forward genetic screen in Drosophila embryos, aimed at isolating genes involved in regulation of neural proliferation and specification, at the single cell resolution. By taking advantage of the restricted expression of the neuropeptide FMRFa in the last-born cell of the NB lineage 5-6T, the Ap4 neuron, we could monitor the entire lineage progression. This screen succeeded in identifying 43 novel genes controlling different aspects of CNS development. One of the genes isolated, Ctr9, displayed extra Ap4/FMRFa neurons. Ctr9 encodes a component of the RNA polymerase II complex Paf1, which is involved in a number of transcriptional processes. The Paf1C, including Ctr9, is highly conserved from yeast to human, and in the past couple of years, its importance for transcription has become increasingly appreciated. However, studies in the Drosophila system have been limited. In the screen, we isolated the first mutant of Drosophila Ctr9 and conducted the first detailed phenotypic study on its function in the Drosophila embryonic CNS. Loss of function of Ctr9 leads to extra NB numbers, higher proliferation ratio and lower expression of neuropeptides. Gene expression analysis identified several other genes regulated by Ctr9, which may explain the Ctr9 mutant phenotypes. In summary, we identified Ctr9 as an essential gene for proper CNS development in Drosophila, and this provides a platform for future study on the Drosophila Paf1C. Another interesting gene isolated in the screen was worniou (wor), a member of the Snail family of transcription factors. In contrast to Ctr9, whichdisplayed additional Ap4/FMRFa neurons, wor mutants displayed a loss of these neurons. Previous studies in our group have identified many genes acting to stop NB lineage progression, but how NBs are pushed to proliferate and generate their lineages was not well known. Since wor may constitute a “driver” of proliferation, we decided to study it further. Also, we identified five other transcription factors acting together with Wor as pro-proliferative in both NBs and their daughter cells. These “drivers” are gradually replaced by the previously identified late-acting “stoppers.” Early and late factors regulate each other and the cell cycle, and thereby orchestrate proper neural lineage progression.
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| 19. |
- Barmano, Neshro, 1980-
(författare)
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Structured management, Symptoms, Health-related Quality of Life and Alcohol in Patients with Atrial Fibrillation
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Atrial fibrillation (AF) is the most common cardiac arrhythmia, affecting at least 2.9 % of the Swedish population. Although AF is associated with increased risk of ischaemic stroke, there have been many reports on the underuse of oral anticoagulants (OAC) and non-adherence to guidelines in other areas as well. AF is also associated with disabling symptoms and decreased health-related quality of life (HRQoL), but some patients are asymptomatic. The reasons for the great variation of symptoms remain unclear. Furthermore, although research on AF has increased, studies have mainly focused on treatment, while studies on risk factors, such as alcohol consumption, have only recently gained attention.The aim of this thesis was to investigate whether structured care of patients with AF could improve guideline adherence and HRQoL compared to standard care, and to determine which factors affect symptoms and HRQoL prior to treatment with radiofrequency catheter ablation (RFA), as well as improvement after RFA. Furthermore, we aimed to examine the associations of alcohol consumption with cardiac biomarkers, the size of the left atrium (LA), and re-ablation.This thesis is based on two studies. In the ‘Structured Management and Coaching – Patients with Atrial Fibrillation’ (SMaC-PAF) study, 176 patients were recruited to the intervention group, receiving a structured follow-up programme, and 146 patients were recruited to the control group, receiving standard care. The two groups were compared in regard to adherence to guidelines and patient-reported outcome measures (PROMs) assessing symptoms and HRQoL.In the ‘Symptom burden, Metabolic profile, Ultrasound findings, Rhythm, neurohormonal activation, haemodynamics and health-related quality of life in patients with atrial Fibrillation’ (SMURF) study, 192 patients referred for their first RFA of AF were included. PROMs questionnaires were filled out, echocardiography was performed, and cardiac biomarkers were analysed. Alcohol consumption was assessed through interview and through analysis of ethyl glucuronide in hair (hEtG). AF recurrence and re-ablation within 12 months were examined.In the first study, after one year, 94% (n=112) and 74% (n=87) of patients with indication for OAC in the intervention and the control groups, respectively, actually received treatment with OAC (p <0.01). Both groups improved in anxiety and HRQoL scores over the year, but in the intervention group, arrhythmia-specific symptoms were less frequently experienced and the SF-36 scores were more similar to the norm population.In the second study, the most important predictors of arrhythmia-related symptoms and HRQoL prior to RFA were anxiety, depression and low-grade inflammation, while frequent AF attacks prior to RFA, freedom from AF recurrence after RFA, female gender, no enlarged LA, absence of diabetes, and the presence of heart failure were significant predictors of improvement in symptoms and HRQoL after RFA. Men with hEtG ≥7 pg/mg had higher levels of cardiac biomarkers, larger LA volumes and a higher re-ablation rate than men with hEtG <7 pg/mg, while no such findings were present in women.In conclusion, structured management was superior to standard care in patients with AF, emphasising the importance of structured care, adjusted to local requirements, in order to improve the care and well-being of patients with AF. Although the reasons for the great variety of symptoms in patients with AF still are not yet fully understood, it seems that psychological factors and inflammation play a role, and that improvement in symptoms and HRQoL after RFA is influenced by gender, diabetes, heart failure, LA size and the frequency of attacks before, as well as freedom from AF after, RFA. Finally, alcohol consumption corresponding to hEtG ≥7 pg/mg was associated with higher levels of cardiac biomarkers, larger LA size and a higher rate of re-ablation in men, implying that men with an hEtG-value ≥7 pg/mg have a higher risk for LA remodelling that could potentially lead to a deterioration of the AF situation.
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| 20. |
- Bednarska, Olga, 1973-
(författare)
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Peripheral and Central Mechanisms in Irritable Bowel Syndrome : in search of links
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Irritable bowel syndrome (IBS) is a chronic visceral pain disorder with female predominance, characterized by recurrent abdominal pain and disturbed bowel habits in the absence of an identifiable organic cause. This prevalent and debilitating disease, which accounts for a substantial economic and individual burden, lacks exact diagnostic tools and effective treatment, since its pathophysiology remains uncertain. The bidirectional and multilayered brain-gut axis is a well-established disease model, however, the interactions between central and peripheral mechanisms along the brain-gut axis remain incompletely understood. One of the welldescribed triggering factors, yet accounting for only a fraction of IBS prevalence, is bacterial gastroenteritis that affects mucosal barrier function. Altered gut microbiota composition as well as disturbed intestinal mucosal barrier function and its neuroimmune regulation have been reported in IBS, however, the impact of live bacteria, neither commensal nor pathogenic, on intestinal barrier has not been studied yet. Furthermore, abnormal central processing of visceral sensations and psychological factors such as maladaptive coping have previously been suggested as centrally-mediated pathophysiological mechanisms of importance in IBS. Brain imaging studies have demonstrated an imbalance in descending pain modulatory networks and alterations in brain regions associated with interoceptive awareness and pain processing and modulation, particularly in anterior insula (aINS), although biochemical changes putatively underlying these central alterations remain poorly understood. Most importantly, however, possible associations between these documented changes on central and peripheral levels, which may as complex interactions contribute to disease onset and chronification of symptoms, are widely unknown.This thesis aimed to investigate the peripheral and central mechanisms in women with IBS compared to female healthy controls (HC) and to explore possible mutual associations between these mechanisms.In Paper I, we studied paracellular permeability and passage of live bacteria, both commensal and pathogenic through colonic biopsies mounted in Ussing chambers. We explored the regulation of the mucosal barrier function by mast cells and the neuropeptide vasoactive intestinal polypeptide (VIP) as well as a correlation between mucosal permeability and gastrointestinal and psychological symptoms. We observed increased paracellular permeability and the passage of commensal and pathogenic live bacteria in patients with IBS compared with HC, which was diminished by blocking the VIP receptors as well as after stabilizing mast cells in both groups. Moreover, higher paracellular permeability was associated with less somatic and psychological symptoms in patients.In Paper II, we aimed to determine the association between colonic mucosa paracellular permeability and structural and resting state functional brain connectivity. We demonstrated different patterns of associations between mucosa permeability and functional and structural brain connectivity in IBS patients compared to HC. Specifically, lower paracellular permeability in IBS, similar to the levels detected in HC, was associated with more severe IBS symptoms and increased functional and structural connectivity between intrinsic brain resting state network and descending pain modulation brain regions. Our findings further suggested that this association between mucosa permeability and functional brain connectivity was mainly mediated by coping strategies.In Paper III, we investigated putative alterations in excitatory and inhibitory neurotransmission of aINS, as the brain’s key node of the salience network crucially involved in cognitive control, in IBS patients relative to HC and addressed possible connections with both symptoms and psychological factors. We found decreased concentrations of the excitatory neurotransmitter Glx in bilateral aINS in IBS patients compared to HC, while inhibitory neurotransmitter GABA+ levels were comparable. Further, we demonstrated hemisphere-specific associations between abdominal pain, coping and aINS excitatory neurotransmitter concentration.In conclusion, this thesis broadens the knowledge on peripheral and central mechanisms in IBS and presents novel findings that bring together the ends of brain-gut axis. Our results depict association between mucosal permeability, IBS symptoms and functional and structural connectivity engaging brain regions involved in emotion and pain modulation as well as underlying neurotransmitter alterations.
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