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Sökning: AMNE:(MEDICAL AND HEALTH SCIENCES Clinical Medicine Gastroenterology and Hepatology) > Doktorsavhandling

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1.
  • Åkerman, Linda, 1983- (författare)
  • Aspects of the Pre-Diabetic Period in Type 1 Diabetes
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Type 1 diabetes (T1D) is an autoimmune disease characterized by insulin deficiency, due to immune-mediated destruction of beta cells. Current knowledge regarding the period preceding disease onset comes, to a large extent, from studying risk cohorts based on relatives of T1D-patients, as they have an increased disease risk. Among T1D patients in general, however, few have the disease in their immediate family. It is therefore important to study risk cohorts from the general population as well. An ongoing autoimmune reaction can often be seen in the blood long before disease onset, by detection of autoantibodies directed towards beta cell antigens. By autoantibody screening among participants in the ABIS (All Babies in the South-east of Sweden) cohort, we could identify a group of children from the general population with increased risk for T1D, positive for multiple autoantibodies. They were enrolled in a 2-year prospective follow-up aiming to characterize the prediabetic period and to identify factors indicative of progression/non-progression to T1D. We assessed glucose homeostasis and autoantibody titers over time, and searched for risk-biomarkers by analyzing the expression of immune-related genes (Th1-Th2-Th3) in peripheral blood mononuclear cells (PBMC) from these children, in comparison to healthy children and newly diagnosed T1D patients. In the same groups we also compared serum micro RNA (miRNA) profiles, knowing that miRNA molecules have desirable biomarker properties. We found that two specific autoantibodies, IA2A and ZnT8A, were detected at higher concentrations in risk-individuals who progressed to overt T1D during or after the follow-up period, compared to those who still have not. We also observed disturbed glucose homeostasis long before onset in the progressors, but it was seen among those who remain symptom free as well. Further, we found support for the possible role of insulin resistance as an accelerator of the disease process. For gene expression and serum miRNA, few differences were observed between risk-individuals and healthy children overall. However, for PBMC gene expression and serum miRNA both, there were associations to beta cell function and glucose homeostasis, and for miRNA also to islet autoantibodies. Although specific profiles for prediction of disease onset or identification of risk-individuals could not be found, these results are interesting and deserve to be evaluated further. As part of another sub-study within ABIS, the effects of physical activity on glucose homeostasis were assessed in healthy schoolchildren. The level of physical activity, measured by pedometers, was related to insulin resistance and beta cell-stress, and decreased physical activity was associated with increased insulin resistance and load on the insulin-producing beta cells, already at school-age.
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2.
  • Lundin, Anna-Carin (författare)
  • Tendinosis in Trigger Finger
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Trigger finger is one of the most common hand conditions, with a prevalence of almost 3%. The aetiology remains unclear even though many causes have been suggested. The prevailing paradigm is that the pathogenesis of trigger finger is ascribed to primary changes in the first fibrous condensation of the tendon sheath (A1-pulley). Several studies have investigated pathology in the pulley, but few have investigated the tendon. The general aim of this thesis was to find out if there is pathology in the trigger finger tendon and to define it.We first looked at trigger finger tendon biopsies in a light microscope, and found that they were histologically different from healthy tendons. They showed signs of micro-ruptures, collagen degradation, increased amounts of ground substance, both hyper- and hypo-cellular areas, round active cell nuclei and absence of inflammatory cells, all similar to tendinosis. The histological picture was further assessed by using a scoring system for Achilles tendinosis. The trigger finger tendons scored high, suggesting a similar histopathology.Next, we performed a quantitative real-time polymerase chain reaction (qPCR) on trigger finger tendons. We assessed the mRNA expression of 10 genes, which have been described to be differently expressed in Achilles tendinosis (collagen 1 and 3, versican, decorin, biglycan, aggrecan, MMP-2, MMP-3, ADAMTS-5, and TIMP-3). The overall expression pattern agreed with previous studies on Achilles tendinosis, suggesting that the cellular function in trigger finger tendons is disturbed in a similar way as in Achilles tendinosis.Recent experimental and observational research has suggested potential side effects of statin treatment on tendons, but firm evidence was lacking. We performed an epidemiological study on two large population-based cohorts. Statin use was found to increase the risk of both trigger finger and tendinosis in the shoulder and Achilles tendons, especially among men. This suggests a similar pathology in trigger finger and tendinosis.We have also studied the time to treatment effect after a single injection of glucocorticoid in trigger finger. Our results suggest that 60-80% of patients can expect resolution of the triggering within 14 days, and half of them within seven days. This result allows correct information to be given to the patient and proper planning of follow-ups.In conclusion, the pathology in trigger finger tendons is similar to tendinosis in other tendons.
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3.
  • Aljabery, Firas (författare)
  • Staging and tumor biological mechanisms of lymph node metastasis in invasive urinary bladder cancer
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Aim: To study the possibility of detecting lymph node metastasis in locally advanced urinary bladder cancer (UBC) treated with radical cystectomy (RC) by using preoperative positron emission tomography/computed tomography (PET/CT) and peroperative sentinel node biopsy (SNB) technique. We also investigate the clinical significance of macrophage traits expression by cancer cells, M2-macrophage infiltration (MI) in tumor stroma and the immunohistochemical expression of biomarkers in cancer cells in relation to clinicopathologic data.Patients and Methods: We studied prospectively 122 patients with UBC, pathological stage pT1–pT4 treated with RC and pelvic lymph node dissection (PLND) during 2005–2011 at the Department of Urology, Linköping University Hospital. In the first study, we compared the results of preoperative PET/CT and conventional CT with the findings of postoperative histopathological evaluation of lymph nodes (LNs). In the second study we investigated the value of SNB technique for detecting pathological LNs during RC in patients with UBC. W also examined the significance of the primary tumor location in the bladder in predicting the site of LN metastases, and the prognostic significance of lympho-vascular invasion (LVI) and lymph node metastasis density (LNMD) on survival. In the third study, we investigate the clinical significance of macrophage infiltration (MI) in tumor stroma and macrophage-traits expression by tumor cells. In the fourth study, we investigate the cell cycle suppression proteins p53, p21, pRb, p16, p14 ARF as well as tumors proliferative protein Ki67 and DNA repair protein ERCC1 expression in cancer cells. The results were compared with clinical and pathological characteristics and outcome.Results: Prior to RC, PET/CT was used to detect LN metastasis in 54 patients. PET/CT had 41% sensitivity, 86% specificity, 58% PPV, and 76% NPV, whereas the corresponding figures for conventional CT were 41%, 89%, 64%, and 77%. SNB was performed during RC in 103 patients. A median number of 29 (range 7–68) nodes per patient were examined. SNs were detected in 83 out of 103 patients (81%). The sensitivity and specificity for detecting metastatic disease by SNB varied among LN stations, with average values of 67% -90%. LNMD or ≥8% and LVI were significantly related to shorter survival. In 103 patients, MI was high in 33% of cases, while moderate and low infiltration occurred in 42% and 25% of tumors respectively. Patients with tumors containing high and moderate compared to low MI had low rate of LN metastases (P=0.06) and improved survival (P=0.06), although not at significant level. The expression of different tumor suppression proteins was altered in 47-91% of the patients. There were no significant association between cancer specific survival (CSS) and any of the studied biomarkers. In case of altered p14ARF, ERCC1 or p21, CSS was low in case of low p53 immunostaining but increased in case of p53 accumulation, although not at a significant level, indicating a possible protective effect of p53 accumulation in these cases.Conclusion: PET/ CT provided no improvement over conventional CT in detection and localization of regional LN metastases in bladder cancer. It is possible to detect the SN but the technique is not a reliable for perioperative localization of LN metastases; however, LVI and LNMD at a cut-off level of 8% had significant prognostic values. MI in the tumor microenvironment but not CD163 expression in tumor cells seems to be synergistic with the immune response against urinary bladder cancer. Our results further indicate that altered p53 might have protective effect on survival in case of altered p14ARF, p21, or ERCC1 indicating an interaction between these biomarkers.
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4.
  • Loftås, Per, 1964- (författare)
  • Response to neoadjuvant treatment in rectal cancer surgery
  • 2016
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Rectal cancer is one of the three most common malignancies in Sweden with an annual incidence of about 2000 cases. Current treatment consists of surgical resection of the rectum including the loco-regional lymph nodes in the mesorectum. In advanced cases, neoadjuvant chemo-radiotherapy (CRT) prior to the operative treatment reduces local recurrences and enables surgery. The neoadjuvant treatment can also eradicate the tumour completely, i.e. complete response. This research project was designed to investigate the effects of preoperative radiotherapy/ CRT and analyze methods to predict response to CRT.Study I investigated the expression of the FXYD-3 protein with immunohistochemistry in rectal cancer, with or without preoperative radiotherapy. The results from the total cohort showed that, strong FXYD-3 expression was correlated to infiltrative tumour growth (p = 0.02). In the radiotherapy group, strong FXYD-3 expression was related to an unfavourable prognosis (p = 0.02). Tumours with strong FXYD-3 expression had less tumour necrosis (p = 0.02) after radiotherapy. FXYD-3 expression in the primary tumour was increased compared to normal mucosa (p=0.008). We concluded that FXYD-3 expression was a prognostic factor in patients receiving preoperative radiotherapy for rectal cancer.Study II investigated FXYD-3 expression in tumours that developed local recurrences following surgery and compared this with expression in tumours that did not develop local recurrences. There was no difference in the expression of FXYD-3 between the group that developed local recurrences and the group that did not develop local recurrences. There was no difference in survival between those with strong or weak FXYD-3 expression. We concluded that this study could not confirm the findings from study 1 i.e. that FXYD-3 expression has prognostic significance in rectal cancer.Study III was a register-based study on the incidence and effects of complete response to neoadjuvant treatment. Eight per cent of the patients with adequate CRT to achieve complete response also had a complete histological response of the luminal tumor in the resected bowel. Sixteen per cent of that group had remaining lymph node metastases in the operative specimen. Chemotherapy together with radiotherapy doubled the chance of complete response in the luminal tumour. Patients with remaining lymph node metastases had a lower survival rate compared to those without. We concluded that residual nodal involvement after neoadjuvant treatment was an important factor for reduced survival after complete response in the luminal tumour.Study IV followed up the results from the previous study by re-evaluating magnetic resonance imaging (MRI)- images in patients with complete tumour response. Two experienced MRI radiologists performed blinded re-staging of post CRT MR- images from patients with complete response in the luminal tumour. One group with lymph node metastases and another one without were studied and the results compared with the pathology reports. The sensitivity, specificity, and positive and negative predicted values for correct staging of positive lymph nodes was 37%, 84%, 70% and 57%. The size of the largest lymph node (4.5 mm, p=0.04) seemed to indicate presence of a tumour positive lymph node. We concluded that MRI couldn’t correctly stage patients for lymph node metastases in patients with complete response to CRT in the luminal tumour.
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5.
  • Jonsson, Åsa, 1969- (författare)
  • How to create and analyze a Heart Failure Registry with emphasis on Anemia and Quality of Life
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Background and aimsHeart failure (HF) is a major cause of serious morbidity and death in the population and one of the leading medical causes of hospitalization among people older than 60 years. The aim of this thesis was to describe how to create and how to analyze a Heart Failure Registry with emphasis on Anemia and Quality of Life. (Paper I) We described the creation of the Swedish Heart Failure Registry (SwedeHF) as an instrument, which may help to optimize the handling of HF patients and show how the registry can be used to improve the management of patients with HF. (Paper II) In order to show how to analyze a HF registry we investigated the prevalence of anemia, its predictors, and its association with mortality and morbidity in a large cohort of unselected patients with HFrEF included in the SwedeHF, and to explore if there are subgroups of HF patients identifying high--‐risk patients in need of treatment. (Paper III) In order to show another way of analyzing a HF registry we assessed the prevalence of, associations with, and prognostic impact of anemia in patients with HFmrEF and HFpEF. (Paper IV) Finally we examined the usefulness of EQ--‐ 5D as a measure of patient--‐reported outcomes among HF patients using different analytical models and data from the SwedeHF, and comparing results about HRQoL for patients with HFpEF and HFrEF.Methods An observational study based on the SwedeHF database, consisting of about 70 variables, was undertaken to describe how a registry is created and can be used (Paper I). One comorbidity (anemia) was applied to different types of HF patients, HFrEF (EF <40%) (II) and HFmrEF (EF 40--‐49% ) or HFpEF (> 50%) (III) analyzing the data with different statistical methods. The usefulness of EQ--‐5D as measure of patient--‐ reported outcomes was studied and the results about HRQoL were compared for patients with HFpEF and HFrEF (IV).ResultsIn the first paper (Paper I) we showed how to create a HF registry and presented some characteristics of the patients included, however not adjusted since this was not the purpose of the study. In the second paper (Paper II) we studied anemia in patients with HFrEF and found that the prevalence of anemia in HFrEF were 34 % and the most important independent predictors were higher age, male gender and renal dysfunction. One--‐year survival was 75 % with anemia vs. 81 % without (p<0,001). In the matched cohort after propensity score the hazard ratio associated with anemia was for all--‐cause death 1.34. Anemia was associated with greater risk with lower age, male gender, EF 30--‐39%, and NYHA--‐class I--‐II. In the third paper (Paper III) we studied anemia in other types of HF patients and found that the prevalence in the overall cohort in patients with EF > 40% was 42 %, in HFmrEF 38 % and in HFpEF (45%). Independent associations with anemia were HFpEF, male sex, higher age, worse New York Heart Association class and renal function, systolic blood pressure <100 mmHg, heart rate ≥70 bpm, diabetes, and absence of atrial fibrillation. One--‐year survival with vs. without anemia was 74% vs. 89% in HFmrEF and 71% vs. 84% in HFpEF (p<0.001 for all). Thus very similar results in paper II and III but in different types of HF patients. In the fourth paper (Paper IV) we studied the usefulness of EQ--‐5D in two groups of patients with HF (HFpEF and HFrEF)) and found that the mean EQ--‐5D index showed small reductions in both groups at follow--‐up. The patients in the HFpEF group reported worsening in all five dimensions, while those in the HFrEF group reported worsening in only three. The Paretian classification showed that 24% of the patients in the HFpEF group and 34% of those in the HFrEF group reported overall improvement while 43% and 39% reported overall worsening. Multiple logistic regressions showed that treatment in a cardiology clinic affected outcome in the HFrEF group but not in the HFpEF group (Paper IV).Conclusions The SwedeHF is a valuable tool for improving the management of patients with HF, since it enables participating centers to focus on their own potential for improving diagnoses and medical treatment, through the online reports (Paper I). Anemia is associated with higher age, male gender and renal dysfunction and increased risk of mortality and morbidity (II, III). The influence of anemia on mortality was significantly greater in younger patients in men and in those with more stable HF (Paper II, III). The usefulness of EQ--‐5D is dependent on the analytical method used. While the index showed minor differences between groups, analyses of specific dimensions showed different patterns of change in the two groups of patients (HFpEF and HFrEF). The Paretian classification identified subgroups that improved or worsened, and can therefore help to identify needs for improvement in health services (Paper IV).
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6.
  • Slind Olsen, Renate (författare)
  • Circulating and genetic factors in colorectal cancer : Potential factors for establishing prognosis?
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Colorectal cancer (CRC) is defined as a cancer appearing in the colon or in the rectum. In Sweden, ~ 6300 individuals were diagnosed with the disease in 2014 and ~ 2550 individuals diagnosed with CRC die each year due to their cancer. Surgery is the main treatment option of CRC and a survival rate of ~ 10 % is estimated if distant metastases have developed. It is therefore of importance to find factors that may be useful together with tumour, node, metastasis (TNM) stage to establish early CRC diagnosis, prognosis and follow-up of CRC patients. The aim of this thesis was to study the possible association of CD93, PLA2G4C, PDGF-D and inflammatory cytokines with CRC disease progression.In a prospective study approach CD93 and PLA2G4C single nucleotide polymorphisms (SNPs) were of potential importance in CRC prognosis.The T/T genotype of CD93 was associated with an increased CD93 expression in CRC tissue. Further, CRC patients carrying this genotype were associated with disseminated CRC at diagnosis and a lower recurrence-free survival after surgery. The A allele of a SNP of PLA2G4C was a stronger predictor for CRC-specific mortality than the conventional risk factors used in the clinic for selection of TNM stage II patients for adjuvant treatment. This indicates that the T/T genotype of CD93 and the A allele of PLA2G4C may be potential genetic factors related to disease severity and spread. Furthermore, they distinguish CRC patients that may benefit from a more comprehensive follow-up and adjuvant treatment.To study the putative involvement of PDGF-D in CRC the effects of PDGF-D signalling was studied in vitro. PDGF-D signalling altered the expression of genes of importance in CRC carcinogenesis and proliferation which was blocked by imatinib, a tyrosine kinase inhibitor. This indicates that PDGF-D signalling may be an important pathway in CRC progression and a potential target in CRC treatment.The analysis of various inflammatory cytokines in plasma at diagnosis showed an association between high levels and increased total- or CRC-specific mortality two years after surgery. High levels of CCL1 and CCL24 was the only cytokines strongly correlated with a worse CRC prognosis after statistical adjustments and may be of interest for further evaluation.In conclusion, this thesis presents circulating and genetic factors such as CD93, PLA2G4C, PDGF-D, CCL1 and CCL24 that may be of importance in CRC progression and may be of clinical value together with TNM stage in establishing prognosis.
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7.
  • Söderquist, Fanny (författare)
  • Melatonin in the gastrointestinal tract
  • 2019
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Melatonin is recognised as the pineal hormone regulating sleep and circadian rhythm. It has also been identified in peripheral tissues (mainly in animals) and thought to display a variety of actions, including anti-inflammatory properties, regulation of gastrointestinal (GI) functions, glucose homeostasis and beneficial effects in different tumour types. Patients with irritable bowel disorder commonly exhibit psychiatric co-morbidity and disturbances of the gut-brain axis have been proposed to play a role in these disorders. The focus of this thesis was to study melatonin and melatonin receptors in the normal human GI tract, the pancreas and small intestinal neuroendocrine tumours. The thesis also explores the complex relationship between GI symptoms and underlying psychiatric traits in the context of elevated levels of peripheral melatonin during waking hours.In paper I-II, tissue samples from the normal human GI tract and pancreas and tumour tissue from small intestinal neuroendocrine tumours were analysed for expression of melatonin and melatonin receptors using immunohistochemistry. For tumour patients, melatonin was also analysed in plasma and set in relation to symptoms and outcome. In paper III-IV, a cohort of young adults (18-25 years) seeking psychiatric care was examined for GI symptoms, melatonin levels in saliva, depressive symptoms and anxiety traits. Psychiatric assessments were performed using structured or semi structured interviews. Depressive symptoms were measured using the self-rating version of the Montgomery-Åsberg Depression Rating Scale; GI symptoms were measured using the Gastrointestinal Symptoms Rating Scale for Irritable Bowel Syndrome; and personality traits were evaluated using the Swedish Universities Scales of Personality.Melatonin and melatonin receptors were widely expressed in the normal human gut and pancreas (paper I) but even in small intestinal neuroendocrine tumours known to produce serotonin (paper II). The intensity of the melatonin immunoreactivity in tumour tissue was found to correlate with lower proliferation index. After treatment, plasma levels of melatonin were reduced in tumour patients. Young adult patients seeking psychiatric care reported more GI symptoms than healthy controls, regardless of the currently active psychotropic medication. The level of GI symptoms was associated with severity of depressive symptoms and trait anxiety (paper III). Higher postprandial levels of melatonin were associated with the GI symptoms of bloating and pain (paper IV).In summary, these findings demonstrate the widespread presence of melatonin in the human gut and confirm a link between melatonin, psychiatric health and GI symptoms.
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8.
  • Forsgren, Mikael (författare)
  • The Non-Invasive Liver Biopsy : Determining Hepatic Function in Diffuse and Focal LiverDisease
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The liver is one of the largest organs within the human body and it handles many vital tasks such as nutrient processing, toxin removal, and synthesis of important proteins. The number of people suffering from chronic liver disease is on the rise, likely due to the present ‘western’ lifestyle. As disease develops in the liver there are pathophysiological manifestations within the liver parenchyma that are both common and important to monitor. These manifestations include inflammation, fatty infiltration (steatosis), excessive scar tissue formation (fibrosis and cirrhosis), and iron loading. Importantly, as the disease progresses there is concurrent loss of liver function. Furthermore, postoperative liver function insufficiency is an important concern when planning surgical treatment of the liver, because it is associated with both morbidity and mortality. Liver function can also be hampered due to drug-induced injuries, an important aspect to consider in drug-development.Currently, an invasive liver needle biopsy is required to determine the aetiology and to stage or grade the pathophysiological manifestations. There are important limitations with the biopsy, which include, risk of serious complications, mortality, morbidity, inter- and intra-observer variability, sampling error, and sampling variability. Cleary, it would be beneficial to be able investigate the pathophysiological manifestations accurately, non-invasively, and on regional level.Current available laboratory liver function blood panels are typically insufficient and often only indicate damage at a late stage. Thus, it would be beneficial to have access to biomarkers that are both sensitive and responds to early changes in liver function in both clinical settings and for the pharmaceutical industry and regulatory agencies.The main aim of this thesis was to develop and evaluate methods that can be used for a ‘non-invasive liver biopsy’ using magnetic resonance (MR). We also aimed to develop sensitive methods for measure liver function based on gadoxetate-enhanced MR imaging (MRI).The presented work is primarily based on a prospective study on c. 100 patients suffering from chronic liver disease of varying aetiologies recruited due to elevated liver enzyme levels, without clear signs of decompensated cirrhosis. Our results show that the commonly used liver fat cut-off for diagnosing steatosis should be lowered from 5% to 3% when using MR proton-density fat fraction (PDFF). We also show that MR elastography (MRE) is superior in staging fibrosis.Finally we presented a framework for quantifying liver function based on gadoxetate-enhanced MRI. The method is based on clinical images and a clinical approved contrast agent (gadoxetate). The framework consists of; state-of the-art image reconstruction and correction methods, a mathematical model, and a precise model parametrization method. The model was developed and validated on healthy subjects. Thereafter the model was found applicable on the chronic liver disease cohort as well as validated using gadoxetate levels in biopsy samples and blood samples. The liver function parameters correlated with clinical markers for liver function and liver fibrosis (used as a surrogate marker for liver function).In summary, it should be possible to perform a non-invasive liver biopsy using: MRI-PDFF for liver fat and iron loading, MRE for liver fibrosis and possibly also inflammation, and measure liver function using the presented framework for analysing gadoxetate-enhanced MRI. With the exception of an MREtransducer no additional hardware is required on the MR scanner. The liver function method is likely to be useful both in a clinical setting and in pharmaceutical trials.
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9.
  • Nord, Maria (författare)
  • Levodopa pharmacokinetics -from stomach to brain : A study on patients with Parkinson’s disease
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Parkinson’s disease (PD) is one of the most common neurodegenerative disorders and it is caused by a loss of dopamine (DA) producing neurons in the basal ganglia in the brain. The PD patient suffers from motor symptoms such as tremor, bradykinesia and rigidity and treatment with levodopa (LD), the precursor of DA, has positive effects on these symptoms. Several factors affect the availability of orally given LD. Gastric emptying (GE) is one factor and it has been shown to be delayed in PD patients resulting in impaired levodopa uptake. Different enzymes metabolize LD on its way from the gut to the brain resulting in less LD available in the brain and more side effects from the metabolites. By adding dopa decarboxylase inhibitors (carbidopa or benserazide) or COMT-inhibitors (e.g. entacapone) the bioavailability of LD increases significantly and more LD can pass the blood-brain-barrier and be converted to DA in the brain. It has been considered of importance to avoid high levodopa peaks in the brain because this seems to induce changes in postsynaptic dopaminergic neurons causing disabling motor complications in PD patients. More continuously given LD, e.g. duodenal or intravenous (IV) infusions, has been shown to improve these motor complications. Deep brain stimulation of the subthalamic nucleus (STN DBS) has also been proven to improve motor complications and to make it possible to reduce the LD dosage in PD patients.In this doctoral thesis the main purpose is to study the pharmacokinetics of LD in patients with PD and motor complications; in blood and subcutaneous tissue and study the effect of GE and PD stage on LD uptake and the effect of continuously given LD (CDS) on LD uptake and GE; in blood and cerebrospinal fluid (CSF) when adding the peripheral enzyme inhibitors entacapone and carbidopa to LD infusion IV; in brain during STN DBSand during oral or IV LD treatment.To conclude, LD uptake is more favorable in PD patients with less severe disease and GE is delayed in PD patients. No obvious relation between LD uptake and GE or between GE and PD stage is seen and CDS decreases the LD levels. Entacapone increases the maximal concentration of LD in blood and CSF. This is more evident with additional carbidopa and important to consider in avoiding high LD peaks in brain during PD treatment. LD in brain increases during both oral and IV LD treatment and the DA levels follows LD well indicating that PD patients still have capacity to metabolize LD to DA despite probable pronounced nigral degeneration. STN DBS seems to increase putaminal DA levels and together with IV LD treatment also increases LD in brain possibly explaining why it is possible to decrease LD medication after STN DBS surgery.
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10.
  • Venetsanos, Dimitrios (författare)
  • Improving management of STEMI patients treated with primary PCI : Pharmacotherapy, renal function estimation and gender perspective
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis focused on the acute management of patients with ST-segment elevation myocardial infarction (STEMI) in an effort to provide information that may improve outcome. The aim was to evaluate the efficacy and safety of bivalirudin versus unfractionated heparin (UFH) in STEMI patients during primary PCI. Furthermore, to provide pharmacodynamic data of novel ways of ticagrelor administration compared to standard tivcagrelor. Additionally, to identify subgroups of patients, such as women who may derive greater benefit from specific antithrombotic strategies due to their risk/benefit profile. Finally, to evaluate current formulas for estimation of renal function in the acute phase of STEMI.In Paper I, all STEMI patients in Sweden between 2008 and 2014, treated with primary PCI and UFH or bivalirudin were included in our analysis. Of the total population of 23 800 patients, 8 783 (36.9%) were included in the UFH group and 15 017 (63.1%) in the bivalirudin group. Concomitant GPI administration was 68.5% in the UFH arm compared to 3.5% in the bivalirudin arm (p<0.01).The adjusted incidence of 30-day mortality was not significant different between the two groups (UFH vs bivalirudin, adjusted HR 0.94; 95% CI 0.82 -1.07). The adjusted risk for 1-year mortality, 30-day and 1-year stent thrombosis and re-infarction did not differ significantly between the two groups. In contrast, patients treated with UFH had a significantly higher incidence of major in-hospital bleeding (adjusted OR 1.62; 95%CI 1.30 -2.03).In Paper II pharmacodynamic data of chewed or crushed ticagrelor compared to standard ticagrelor loading dose (LD) was assessed in 99 patients with stable angina. Platelet reactivity (PR) was assessed with VerifyNow before, 20 and 60 minutes after LD. High Residual platelet reactivity (HRPR) was defined as > 208 P2Y12 reaction units (PRU). Chewed ticagrelor tablets resulted in significantly lower PRU values compared to crushed or integral tablets at 20 and 60 minutes. Crushed ticagrelor LD resulted in significantly lower PRU values compared to integral tablets at 20 minutes whereas no difference was observed at 60 minutes. At 20 minutes, no patients had HRPR with chewed ticagrelor compared to 68% with integral and 30% with crushed ticagrelor LD (p<0.01).In Paper III we presented a pre-specified gender analysis of the ATLANTIC trial including 1 862 STEMI patients that were randomly assigned to pre-hospital versus in-hospital administration of 180mg ticagrelor. Women were older and had higher TIMI risk score. Women had a 3-fold higher risk for all-cause mortality compared to men (5.7% vs 1.9%, HR 3.13, 95% CI 1.78 – 5.51). However, after adjustment for baseline characteristics, the difference was lesser and no longer significant (HR 1.98, 95% CI 0.97 – 4.04). Female gender was not an independent predictor of risk for bleeding after multivariable adjustments (BARC type 3-5 HR 1.52, 95% CI 0.74-3.09). There was no interaction between gender and efficacy or safety of randomised treatment.In Paper IV, forty patients with PCI- treated STEMI were included between November 2011 and February 2013. We validated the performance of the Cockcroft-Gault (CG), the Modification of Diet in Renal Disease (MDRD-IDMS), the Chronic Kidney Disease Epidemiology (CKD-EPI) and the Grubb relative cystatin C (rGCystC) equations for estimation of GFR against measured GFR (mGFR) during the index hospitalisation for STEMI.MDRD-IDMS and CKD-EPI demonstrated a good performance to estimate GFR with accuracy within 30% (P30) 82.5% vs 82.5%, respectively. CKD was best classified by CKD-EPI (Kappa 0.83). CG showed the worst performance with the lowest P30. The rG-CystC equation had a marked bias of -17.8% and significantly underestimated mGFR (p=0.03).Conclusions – In STEMI patients treated with primary PCI, bivalirudin should be preferred in patient at high risk for bleeding. With crushed or chewed ticagrelor tablets a more rapid platelet inhibition may be achieved, compared with standard integral tablets. In STEMI patients, fast and potent platelet inhibition with chewed ticagrelor may reduce the risk of early stent thrombosis and patients treated with a less aggressive antithrombotic strategy, such as UFH or bivalirudin monotherapy, may derive a greater benefit. Although gender differences in adverse outcomes could mainly be explained by older age and clustering of comorbidities in women, a bleedreduction strategy in women with high risk characteristics is warranted in order to improve their outcome. Regardless the choice of antithrombotic strategy, dose adjustment of drugs cleared by kidneys based on GFR estimation is of crucial importance. MDRD and CKD-EPI should be the formulas used for estimation of GFR in STEMI patients
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