Electrochemical biosensors are renowned for their ability to detect a wide range of analytes in biological fluids for clinical diagnosis. The implementation of biomarkers in electrochemical biosensors for clinical diagnosis is essential for the specific and accurate diagnosis of the disease with high sensitivity and selectivity. Therefore, this thesis evaluates the challenges pertaining to the stability, reproducibility, and obtaining a low limit of detection for the internal/external biomarkers associated with two distinct electrochemical biosensors. The first study tackles the challenge of detecting low analyte concentrations in a label-free biosensor. It introduces an innovative label-free electrochemical biosensing method for the detection of glycosylated hemoglobin (HbA1c) and C-reactive protein (CRP) to predict Coronary Heart Disease (CHD) progression using tailored redox probes, proposing a dual biomarker biosensing platform for future research. Calibration curves reveal an LOD of 5 mg/mL in PBS (8) FeCN (II) and 6 mg/mL in SB for a linear range of 0 – 30 mg/mL of HbA1c. Similarly, an LOD of 0.007 mg/mL and 0.008 mg/mL in PBS (7.4) PcA-NO2 and SB, respectively, is reported for a linear range of 0 – 0.05 mg/mL of CRP. The second study focuses on stabilizing a biomolecule-free sensor for the ultra-low detection of Δ9-tetrahydrocannabinol (THC) in roadside testing. Pre-depositing THC, an external biomarker for drug-impaired driving, onto the biosensor's working electrode enhances its interaction with analytes. However, THC's oxidative nature compromises sensor stability during manufacturing. Consequently, optimal electrode storage conditions were explored, indicating frozen storage as ideal for up to six months, effectively preventing THC oxidation at -18°C, while degradation occurs at 4°C. Modified electrodes stored under optimal conditions exhibit improved calibration curves when exposed to various THC samples. / Thesis / Master of Applied Science (MASc) / An electrochemical biosensor is a sensing device with the ability to detect biological species via the transduction of a specific biological event into electrochemical signals. These sensors are extremely useful for the detection of analytes in biological fluids for clinical diagnostics, to determine the presence or absence of diseases. This manuscript addresses the challenges associated with the stability, reproducibility, and the low limits of detection associated with screen-printed carbon electrodes used in electrochemical biosensing. Subsequently, due to the strong correlation between glycated hemoglobin (HbA1c) and C-reactive protein (CRP) to connote the risk of contracting coronary heart disease (CHD), the manuscript presents a novel label-free electrochemical biosensing method for the detection of HbA1c and CRP with low detection limits. Secondly, the manuscript identifies ambient storage conditions for the long-term stability of a biomolecule-free sensing device for the roadside detection of ultra-low concentrations of Δ9-tetrahydrocannabinol (THC).

The COVID-19 pandemic affected regular health care for patients with chronic diseases. However, the impact of the pandemic on primary care for patients with coronary artery disease (CAD) who are enrolled in a structured disease management program (DMP) in Germany is not clear. We investigated whether the pandemic affected primary care and health outcomes of DMP-CAD patients (n = 750) by using a questionnaire assessing patients’ utilization of medical care, CAD symptoms, as well as health behavior and mental health since March 2020. We found that out of concern about getting infected with COVID-19, 9.1% of the patients did not consult a medical practitioner despite having CAD symptoms. Perceived own influence on infection risk was lower and anxiety was higher in these patients compared to symptomatic CAD patients who consulted a physician. Among the patients who reported chest pain lasting longer than 30 min, one third did not consult a medical practitioner subsequently. These patients were generally more worried about COVID-19. Patients with at least one worsening CAD symptom (chest pain, dyspnea, perspiration, or nausea without apparent reason) since the pandemic showed more depressive symptoms, higher anxiety scores, and were less likely to consult a doctor despite having CAD symptoms out of fear of infection. Our results provide evidence that the majority of patients received sufficient medical care during the COVID-19 pandemic in Germany. However, one in ten patients could be considered particularly at risk for medical undersupply and adverse health outcomes. The perceived infection risk with COVID-19 might have facilitated the decision not to consult a medical doctor.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

This research study examines the manner in which a cardiological sample presents in terms of their psychological make-up by making specific reference to the constructs self-concept and emotions. A literature overview of different aspects of self-concept, emotion and cardiology places the results and discussions of the study within a theoretical background. The study supplies descriptive information relating to the demographic profile of the sample, followed by a description of various aspects of self-concept and emotions, as well as a correlational exploration of the manner in which the sample group presents. The sample consisted of 29 individuals, all who had been diagnosed with coronary heart disease (CHD) and been subjected to surgery as a result thereof. The participants completed a questionnaire, containing two measurement instruments, namely the Adolescent Self-Concept Scale (ASCS) and the Emotions Profile Index (EPI). The scores, obtained by the sample, were subjected to statistical analysis to provide a self-conceptual and emotional profile of the sample. The Spearman Rank-Order Correlation Coefficient was then used to indicate the extent to which the sample tended towards portraying themselves in a positive light, more than they might be experiencing. The study further refers to the views of the sample group, relating to these findings, as obtained from an information and discussion session held with them. The study indicate a significant statistical trend amongst the sample group to portray themselves in a positive light in relation to emotions, even though they were not in reality experiencing such positive emotions. Although the same positive trend was indicated with self-concept, the study cannot conclusively indicate that this is not a realistic presentation of the sample group as a whole. / Dissertation (Counselling Psychology)--University of Pretoria, 2006. / Psychology / unrestricted

<p dir="ltr">H3K27me3 is a transcriptional repressive epigenetic mark that plays vital roles in many biological processes in <i>Arabidopsis thaliana</i>. A number of biochemical and functional characterizations of PKL, an ATP-dependent CHD chromatin remodeler, suggest that PKL contributes to maintain the homeostasis of H3K27me3. To identify other factors that act with PKL together to contribute to the homeostasis of H3K27me3, we undertook an EMS-mutagenesis screen for <i>pkl</i>-associated phenotypes. This genetic screen suggests that PKL may contribute to maintaining the homeostasis of H3K27me3 in an H2A.Z associated or a Mediator associated pathway.</p><p dir="ltr">Here, we took advantage of a combined genetic and bioinformatic method to characterize the contribution of PKL in these two pathways as described above. Our analysis revealed a robust genetic interaction between <i>HTA9</i>, <i>HTA11</i>, and <i>PKL</i> in maintaining proper H2A.Z distribution and enrichment of H3K27me3. In addition, the characterization also sheds light on unexpected roles of PKL in promoting the homeostasis of H3K4me3 and acting with histone demethylases to promote removal of H3K27me3 in an H2A.Z dependent manner. Furthermore, our result also raised the possibility that the tail module of the Mediator complex also plays a critical role in the homeostasis of H3K27me3. While we were examining <i>PKL</i>-dependent chromatin features, we largely optimized the protocol for preparation ChIP-seq samples and libraries and implemented a gene-centric ChIP-seq bioinformatics pipeline for providing robust analysis.</p><p dir="ltr">Ultimately, the work presented in this thesis highlights several divergent pathways that PKL contributes to maintain chromatin homeostasis. By and large, the combined observation from this thesis advances our knowledge of how PKL interacts with other chromatin-associated machineries together to maintain proper epigenetic states and promote other more emergent DNA-templated processes, including replication and transcription.</p>

Acute myocardial infarction (AMI), caused by ischaemic heart disease (IHD), is a leading cause of death in both men and women in the western society. Hypertension, diabetes, and smoking are examples of well-known risk factors of IHD, but also there are psychosocial factors, such as stress, vital exhaustion (unusual fatigue, irritability, and demoralization) and depression that have been associated with an increased risk in both genders. After an AMI, however, women are more likely than men to be psychosocially impaired resulting in suffering and a presumed increase in the risk of recurrent cardiac events. Psychosocial factors may be targeted in secondary prevention, complementary to drug treatment and conventional lifestyle advice. There is some evidence of beneficial effects on both psychosocial well-being and cardiac outcomes by psychosocial interventions in men. Far fewer women have been studied and the results have been inconsistent. It is not clear how psychosocial factors convey the increased risk of cardiac events, but many possible psychopathological mechanisms, including biochemical and physiological links, have been suggested. In the Women’s Hearts study we have, in a randomised controlled trial, evaluated a one-year cognitive-behavioural stress management programme designed specifically for women with IHD. We included 198 women with IHD, with a mean age of 61 years and from the county of Västerbotten in Northern Sweden, who were randomised to either conventional treatment and follow-up, or to stress management in addition to conventional care. Extensive questionnaires, blood samplings, and biomedical and physiologic data were obtained before randomisation, as well as at follow-ups approximately one and two years after randomisation. Two groups of healthy controls were included for comparisons with women with IHD. Compared to women without IHD, women with IHD reported more stress behaviour and vital exhaustion. Women with IHD also had a lower heart rate variability (HRV) than the healthy controls, possibly reflecting a dysfunctional autonomic nervous regulation of the heart. Reduced HRV has been shown to increase the risk of cardiac arrhythmias and sudden death. At the first follow-up, performed at the end of the one-year stress management programme, women who had participated in the programme had reduced the stress behaviour and vital exhaustion, compared to the women in the conventional care group. We could not find any evidence of a direct cause-effect relationship between stress management and biological cardiovascular risk indicators, or HRV; the intervention and control groups did not differ in insulin resistance, inflammatory, haemostatic and fibrinolytic factors, or HRV. At second follow-up one year later, several additional psychosocial domains were studied. The stress management programme had accelerated psychosocial recovery at the first follow-up over and above that observed in the control group. At the second follow-up, there was further marked improvement in the control group, so the differences in psychosocial variables between the intervention and control groups were no longer significant. In conclusion, a cognitive-behavioural stress management programme could accelerate psychosocial improvement in women with IHD, and thus reduce the amount of psychological and psychosocial suffering. We could not find any evidence that the stress management programme was associated with a concomitant improvement in biological cardiovascular risk indicators, or HRV. Our results suggest that the women with the greatest psychosocial burden should be identified and targeted in new clinical trials of cognitive-behavioural interventions in women with IHD. Future studies within the Women’s Hearts project will evaluate the psychosocial effects at a five-year follow-up, as well as investigations of other possible pathways by which psychosocial interventions might mediate beneficial effects on cardiac events.

HINTERGRUND: Die meist wöchentlich stattfindende Lipidapherese (LA) kommt bei Patienten mit therapierefraktärer Hyperlipoproteinämie sekundärpräventiv zum Einsatz. Während umfangreiche Informationen zu deren Effizienz und Sicherheit vorliegen, fehlen valide Erhebungen zum subjektiven Befinden von Lipidapheresepatienten (LAP) und deren Erleben der invasiven extrakorporalen Behandlung. METHODEN: Diese monozentrisch durchgeführte Untersuchung schloss 23 LAP mit nachgewiesener KHK sowie 32 hospitalisierte nicht-extrakorporal behandelte KHK-Patienten (NEKP) und 31 Hämodialysepatienten (HDP) ein. Es erfolgten alters-, geschlechts- und morbiditätsadjustierte Vergleiche von gesundheitsbezogener Lebensqualität (GLQ) mittels PLC (Profil der Lebensqualität chronisch Kranker), Angst und Depressivität (HADS-D=deutsche Version der Hospital Anxiety and Depression Scale; Cutoff jeweils >7), Krankheitsverarbeitung (FKV-LIS=Freiburger Fragebogen zur Krankheitsverarbeitung) sowie des bei LAP und HDP anhand von Interviews erfassten Erlebens der extrakorporalen Behandlung. ERGEBNISSE: Von den LAP hatten 39.1% einen auffälligen HADS-D-Wert für Angst und 17.4% für Depressivität. Sowohl hinsichtlich dieser Symptome als auch der psychischen und sozialen GLQ waren die LAP den NEKP nicht unterlegen, während sie eine signifikant bessere physische GLQ aufwiesen. Im Vergleich mit den HDP zeigte sich eine jeweils teilweise signifikant bessere physische, psychische und soziale GLQ bei den LAP. Sie waren zudem signifikant weniger depressiv und tendenziell weniger ängstlich. Gegenüber den HDP gaben die LAP eine signifikant geringere Belastung (5.3 vs. 2.7 von 10) durch ihre extrakorporale Behandlung an. 72% nahmen die LA-Therapie als entlastend wahr (gegenüber 69% bei den HDP) und 70% würden sie uneingeschränkt weiterempfehlen. Unter den LAP dominierten eher vorteilhafte Krankheitsverarbeitungsmechanismen, worin sie sich allerdings nicht von den NEKP und HDP unterschieden. SCHLUSSFOLGERUNG: Die Akzeptanz der LA durch die Patienten und deren im Vergleich gute GLQ sowie psychische Befindlichkeit sind beachtlich. Durch die effektive ’Blutreinigung’ allein sind diese Ergebnisse jedoch nicht zu erklären. So drängen sich Fragen zu weiteren, auch psychischen, Wirkmechanismen der LA-Therapie auf.

Unambiguous gender identification (ID) is needed to assess parameters in studies of population dynamics, behavior, and evolutionary biology of Caribbean Flamingo (Phoenicopterus ruber ruber) and other birds. Due to its importance for management and conservation, molecular (DNA-based) avian gender ID assays targeting intron-size differences of the Chromosome Helicase ATPase DNA Binding (CHD) gene of males (CHD-Z) and females (CHD-W) have been developed. Male (ZZ) and female (WZ) genotypes are usually scored as size polymorphisms through agarose or acrylamide gels. For certain species, W-specific restriction sites or multiplex polymerase chain-reaction (PCR) involving CHD-W specific primers are needed. These approaches involve a minimum of three steps following DNA isolation: PCR, gel electrophoresis, and photo-documentation, which limit high throughput scoring and automation potential. In here, a short amplicon (SA) High-resolution Melting Analysis (HRMA) assay for avian gender ID is developed. SA-HRMA of an 81-Base Pair (bp) segment differentiates heteroduplex female (WZ) from homoduplex male (ZZ) genotypes by targeting Single-nucleotide Polymorphisms (SNPs) instead of intron-size differences between CHD-Z and CHD-W genes. To demonstrate the utility of the approach, the gender of Caribbean Flamingo (P. ruber ruber) (17 captive from the Dallas Zoo and 359 wild from Ria Lagartos, Yucatan, Mexico) was determined. The assay was also tested on specimens of Lesser Flamingo (P. minor), Chilean Flamingo (P. chilensis), Saddle-billed Stork (Ephippiorhynchus senegalensis), Scarlet Ibis (Eudocimus ruber), White-bellied Stork (Ciconia abdimii), Roseate Spoonbill (Platalea ajaja), Marabou Stork (Leptoptilos crumeniferus), Greater Roadrunner (Geococcyx californianus), and Attwater's Prairie Chicken (Tympanuchus cupido attwateri). Although the orthologous 81 bp segments of Z and W are highly conserved, sequence alignments with 50 avian species across 15 families revealed mismatches affecting one or more nucleotides within the SA-HRMA forward or reverse primers. Most mismatches were located along the CHD-Z gene that may generate heteroduplex curves and thus gender ID errors. For such cases, taxon and species-specific primer sets were designed. The SA-HRMA gender ID assay can be used in studies of avian ecology and behavior, to assess sex-associated demographics and migratory patterns, and as a proxy to determine the health of the flock and the degree by which conservation and captive breeding programs are functioning.