Assessment of Pulmonary Blood Flow in Heart Failure. Using Novel and Non-Invasive Diagnostic Methods.

In heart failure (HF), the heart is unable to pump effectively in order to satisfy the demands of the body. The elevated filling pressure seen in HF leads to accumulation of fluid in the lungs, i.e pulmonary congestion. While investigation with chest X-ray is recommended, it has limitations in detecting pulmonary congestion. Ventilation/perfusion single-photon emission computed tomography (V/P SPECT), i.e tomographic lung scintigraphy, is a promising method to diagnose and quantify pulmonary congestion in HF but needs to be validated by invasive right-heart catheterization. The variation of the blood volume in the pulmonary circulation measured by magnetic resonance imaging (MRI) may also have the potential to quantify the severity of HF.The general aim of this thesis was to develop and validate new non-invasive methods to diagnose and quantify pulmonary congestion and variation of the pulmonary blood flow in patients with HF, as well as to follow-uppulmonary congestion.Paper I revealed that the degree of pulmonary congestion in HF could be diagnosed and quantified using V/P SPECT. It was validated with right-heart catheterization. V/P SPECT was more accurate than chest X-ray in diagnosing pulmonary congestion in HF.In Paper II V/P SPECT showed that the pulmonary perfusion pattern was improved and that V/P SPECT could be used to follow treatment effect after heart transplantation in patients with HF and quantify the degree of pulmonarycongestion. It was validated with right-heart catheterization.Paper III demonstrated that V/P SPECT could be used to follow treatment effect and assess the degree of pulmonary congestion in patients with HF after receiving cardiac resynchronization therapy (CRT). V/P SPECT was associated with improvement in patients’ symptoms.Paper IV showed that the pulmonary blood volume variation differed between patients with HF and healthy controls. In patients with HF, approximately 40% of the variation could be explained by the left ventricular longitudinal contribution to stroke volume and the phase shift between the in- and outflow to the pulmonary circulation. The remaining variation (60%) likely occur on a small vessel level.In summary, pulmonary congestion in HF is difficult to quantify objectively. The non-invasive methods V/P SPECT and MRI might add complementary information in the diagnosis of HF. V/P SPECT can be used to follow treatment effects after heart transplantation and CRT and may have a role in avoiding invasive right-heart catheterization in selected cases and aid in treatment decision

Bacteria associated with inflammatory lesions of the enteric tract of cattle

Summary available; p. xxiii-xxvi

Investigation of nanostructured conducting polymers and graphene/polyaniline nanocomposite based thin films for hydrogen gas sensing

Novel conductometric and layered Surface Acoustic Wave (SAW) hydrogen gas sensors based on nanostructured conducting polymers and graphene/polyaniline nanocomposite are reported in this PhD dissertation. Template-free electropolymerization and/or chemical polymerization methods were employed during the synthesis of the nanostructured polythiophene, polypyrrole, polyaniline, polyanisidine, polyethylaniline and graphene/polyaniline nanocomposite which were investigated for their hydrogen gas sensing characteristics. The nanostructured gas sensitive films' physical and chemical properties were studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Ultraviolet-visible spectroscopy (UV-Vis), and X-ray photoemission spectroscopy (XPS). A programmable gas calibration and data acquisition system was utilized to measure the sensors' responses towards several concentrations of hydrogen gas at room temperature. A comparative study on the performance of conductometric hydrogen gas sensors based on electropolymerized polythiophene nanostructured films was conducted for the first time in this thesis according to the best of the author's knowledge. Polythiophene gas sensitive films featuring nanofibers with diameters of 10-40 nm were successfully electrodeposited on conductometric transducers. Electropolymerization parameters such as counterion's type, the concentration of the electrolyte, the electropolymerization potential and the deposition time were shown to affect the morphology of the gas sensitive film and ultimately its response towards hydrogen gas. Electropolymerized polypyrrole nanowires with diameters of 40-90 nm and chemically polymerized polypyrrole nanofibers of 18 nm in diameter were employed for hydrogen gas sensing for the first time herein. The effect of polypyrrole's counterion type on the resultant gas sensor electrical characteristics was investigated herein. Via a comprehensive investigation, it was found that chemically synthesized chloride-doped polypyrrole nanofibers to be more sensitive to hydrogen gas than the perchlorate-doped electropolymerized polypyrrole nanowires due to the smaller molecular size of the incorporated counterion into the polymer matrix. Novel layered SAW gas sensors based on polythiophene nanofibers, polypyrrole nanofibers, nanoporous polyaniline, polyanisidine nanofibers and polyethylaniline nanofibers were developed and tested at room temperature. The highest response was observed for the polyanisidine nanofibers/ZnO/36° YX LiTaO 3 SAW gas sensor with a 294 kHz frequency shift from the centre frequency upon exposure to hydrogen gas with the concentration of 1% in ambient air. Morphological analysis of the deposited polyanisidine nanofibers based thin film revealed that the nanofibers, ~55 nm in diameter, were not densely packed that allows deep and efficient penetration of target gas molecules into the sensitive film and makes gas sensing possible over the entire length of a nanofiber into a mesh. To the best knowledge of the author of this dissertation, the first ever reported hydrogen gas sensor based on graphene/polyaniline nanocomposite was developed and characterized for the first time in this PhD program. This sensor outperformed hydrogen gas sensors based on polyaniline nanofibers at room temperature. After analysing the nanocomposite's characterization results, the author of this thesis suggested that the observed high response is attributed to the graphene/polyaniline nanocomposite's high surface area compared to that of the pure polyaniline nanofibers due to the growth of polyaniline nanofibers in the order of 25-50 nm in diameter on the graphene nanosheets' surfaces

Conductometric hydrogen gas sensor based on polypyrrole nanofibers

Polypyrrole nanofibers are synthesized through a template-free chemical route and used as the active component for hydrogen gas sensing at room temperature. The synthesis of polypyrrole nanofibers was achieved by using bipyrrole as an initiator to speed up the polymerization of pyrrole with FeCl as the oxidizing agent. Scanning and transmission electron microscopy studies indicate that the resulting polypyrrole forms a nanofibrous mat with average nanofiber diameter of 18 nm. Fourier transform infrared spectroscopy and elemental analysis confirms that the structure of the nanofibers is comparable to bulk polypyrrole. Gas sensing properties of polypyrrole nanofibers were investigated by depositing nanofiber dispersions on an interdigited conductometric transducer. The sensor performance was tested through programmable exposure towards different concentrations of hydrogen gas diluted in synthetic air in an environmental cell at different temperatures. A short response time of 43 s was observed upon exposure to a concentration of 1% hydrogen with a decrease in film resistance of 312 at room temperature. The sensor sensitivity was analyzed with gradual elevation of the operating temperature

Axiomatic/asymptotic evaluation of multilayered plate theories by using single and multi-points error criteria

AbstractThis paper deals with refined theories for multilayered composites plates. Layer-Wise (LW) and Equivalent Single Layer (ESL) theories are evaluated by means of axiomatic–asymptotic approach. Theories with forth order displacement fields in the thickness layer/plate direction z are implemented by referring to the Unified Formulation by Carrera. The effectiveness of each term of the made expansion is evaluated by comparing the related theories with a reference solution. As a result a reduced model is obtained which preserve the accuracy of the full-model (model that include the whole terms of the z-expansion) but it removes the not-significant terms in the same expansion (those terms that do no improve the results according to a given error criteria). Various single-point and multi-point error criteria have been analyzed and compared in order to establish such an effectiveness: error localized in an assigned point along z, error localized at each interface, error located at the z-value corresponding to the maximum value of the considered variables, etc. Applications are given in case of closed form solutions of orthotropic cross-ply, rectangular, simply supported plates loaded by bisinusoidal distribution of transverse pressure. Symmetrically and unsymmetrical laminated cases are considered along with sandwich plates. It is found the reduced model is strongly influenced by the used localized error and that in same case the reduced model which is obtained by of single point criteria can be very much improved by the use of multi-point criteria

The brain-enriched microRNA miR-124 in plasma predicts neurological outcome after cardiac arrest

Introduction: Early prognostication after successful cardiopulmonary resuscitation is difficult, and there is a need for novel methods to estimate the extent of brain injury and predict outcome. In this study, we evaluated the impact of the cardiac arrest syndrome on the plasma levels of selected tissue-specific microRNAs (miRNAs) and assessed their ability to prognosticate death and neurological disability. Methods: We included 65 patients treated with hypothermia after cardiac arrest in the study. Blood samples were obtained at 24 hours and at 48 hours. For miRNA-screening purposes, custom quantitative polymerase chain reaction (qPCR) panels were first used. Thereafter individual miRNAs were assessed at 48 hours with qPCR. miRNAs that successfully predicted prognosis at 48 hours were further analysed at 24 hours. Outcomes were measured according to the Cerebral Performance Category (CPC) score at 6 months after cardiac arrest and stratified into good (CPC score 1 or 2) or poor (CPC scores 3 to 5). Results: At 48 hours, miR-146a, miR-122, miR-208b, miR-21, miR-9 and miR-128 did not differ between the good and poor neurological outcome groups. In contrast, miR-124 was significantly elevated in patients with poor outcomes compared with those with favourable outcomes (P < 0.0001) at 24 hours and 48 hours after cardiac arrest. Analysis of receiver operating characteristic curves at 24 and 48 hours after cardiac arrest showed areas under the curve of 0.87 (95% confidence interval (CI) = 0.79 to 0.96) and 0.89 (95% CI = 0.80 to 0.97), respectively. Conclusions: The brain-enriched miRNA miR-124 is a promising novel biomarker for prediction of neurological prognosis following cardiac arrest

Assessed and discharged - diagnosis, mortality and revisits in short-term emergency department contacts

BACKGROUND: Emergency departments (EDs) experience an increasing number of patients. High patient flow are incentives for short duration of ED stay which may pose a challenge for patient diagnostics and care implying risk of ED revisits or increased mortality. Four hours are often used as a target time to decide whether to admit or discharge a patient. OBJECTIVE: To investigate and compare the diagnostic pattern, risk of revisits and short-term mortality for ED patients with a length of stay of less than 4 h (visits) with 4–24 h stay (short stay visits). METHODS: Population-based cohort study of patients contacting three EDs in the North Denmark Region during 2014–2016, excluding injured patients. Main diagnoses, number of revisits within 72 h of the initial contact and mortality were outcomes. Data on age, sex, mortality, time of admission and ICD-10 diagnostic chapter were obtained from the Danish Civil Registration System and the regional patient administrative system. Descriptive statistics were applied and Kaplan Meier mortality estimates with 95% CI were calculated. RESULTS: Seventy-nine thousand three hundred forty-one short-term ED contacts were included, visits constituted 60%. Non-specific diagnoses (i.e. symptoms and signs and other factors) were the most frequent diagnoses among both visits and short stay visits groups (67% vs 49%). Revisits were more frequent for visits compared to short stay visits (5.8% vs 4.2%). Circulatory diseases displayed the highest 0–48-h mortality within the visits and infections in the short stay visits (11.8% (95%CI: 10.4–13.5) and (3.5% (95%CI: 2.6–4.7)). 30-day mortality were 1.3% (95%CI: 1.2–1.5) for visits and 1.8% (95%CI: 1.7–2.0) for short stay visits. The 30-day mortality of the ED revisits with an initial visit was 1.0% (0.8–1.3), vs 0.7% (0.7–0.8) for no revisits, while 30-day mortality nearly doubled for ED revisits with an initial short stay visit (2.5% (1.9–3.2)). CONCLUSIONS: Most patients were within the visit group. Non-specific diagnoses constituted the majority of diagnoses given. Mortality was higher among patients with short stay visits but increased for both groups with ED revisits. This suggest that diagnostics are challenged by short time targets

The Evaluation of Calcium Score Validity in the Diagnosis of Patients with Coronary Artery Disease by Using CT Angiography

Background: Coronary artery disease is one of important diseases as in many cases ends up with death. Among many types of coronary artery disease is the lipoprotein plaque deposition on the artery wall. Many reports appeared in the literature concerning the causes, investigation, and treatment of the coronary artery disease. As computed tomography scanners were developed, a new non-invasive procedure was introduced using the calcium present in the plaque as an indicator for the amount of plaque in the coronary artery. Objective: To investigate the validity of the calcium score in the diagnosis of coronary artery disease, and also to find the relation between calcium score with calcification and plaque. Patients and methods: Sixty one patients 40 were men and 21 were women evaluated for calcium score. They had symptoms of chest pain and were subjected to electro cardio gram examination to determine their eligibility for computed tomography angiography to investigate the coronary calcification as a marker of atherosclerosis. The history of diseases including hypertension and diabetes were recorded and check renal function test. Anthropometric measurements and the level of fasting lipid profile for patients and normal subjects were tasted. Patients were advised to come fasting prior to the   examination. They have been given Beta blocker to reduce the heart rate in the range of 55-65 beats/min. Contrast medium was injected IV by means of injector immediately before scanning. Results: Results revel that not all patients suffering from chest pain with electro cardio gram changes show high calcium score; on the other hand patients with high calcium score they have an increased plaque in their coronary artery. At low calcium score calcium score           (0-100), cholesterol, triglyceride and high density lipoprotein are generally inversely proportional with calcium score with the exception of LDL remains virtually unchanged throughout the whole range of calcium score (0 > 300) as appear in the figures . While at high calcium score concentration (>300) lipoproteins are directly proportional with calcium score in contrast with high density lipoprotein which is inversely proportional with calcium Score

HLA Profile in Iraqi Rheumatic Valvulitis Patients

Background: Human leukocyte antigen (HLA) is the most polymorphic genetic system in man. The genes of this region influence susceptibility to certain disease. Objectives: This study was established to shed light on the possible association of HLA class I and II antigens with RV patients. Patients and Methods: Lymphocytotoxicity assay for HLA for class I and II typing had been done for (100) Iraqi patients suffering from rheumatic valvulitis (RV), the control groups consisting of (75 healthy individuals and 35 non rheumatic heart disease (NRHD) patients ). Results: The results showed a significant association of A33-Ags with these patients as compared with healthy and cardiac controls (P=0.005), (P=0.033) respectively. Another interesting finding was the low frequency of A1 in RV patients when compared with healthy control (p=0.002), suggesting that A1 allele may confer protective effect against this disease. In addition significant association between blood group B and RV was evident (p=0.04). An interesting observation was a strong association of blood group B and A33 among those patients (P<0.001). Conclusion: The present results are consistent with hypothesis that susceptibility to RV is genetically linked and in turn may be associated mainly with A33 in Iraqi patients

Sister Mary Joseph's Nodule at a University Teaching Hospital in Northwestern Tanzania: A Retrospective Review of 34 cases.

Sister Mary Joseph's nodule is a metastatic tumor deposit in the umbilicus and often represents advanced intra-abdominal malignancy with dismal prognosis. There is a paucity of published data on this subject in our setting. This study was conducted to describe the clinicopathological presentation and treatment outcome of this condition in our environment and highlight challenges associated with the care of these patients, and to proffer solutions for improved outcome. This was a retrospective study of histologically confirmed cases of Sister Mary Joseph's nodule seen at Bugando Medical Centre between March 2003 and February 2013. Data collected were analyzed using descriptive statistics. A total of 34 patients were enrolled in the study. Males outnumbered females by a ratio of 1.4:1. The vast majority of patients (70.6%) presented with large umbilical nodule > 2 cm in size. The stomach (41.1%) was the most common location of the primary tumor. Adenocarcinoma (88.2%) was the most frequent histopathological type. Most of the primary tumors (52.9%) were poorly differentiated. As the disease was advanced and metastatic in all patients, only palliative therapy was offered. Out of 34 patients, 11 patients died in the hospital giving a mortality rate of 32.4%. Patients were followed up for 24 months. At the end of the follow-up period, 14(60.9%) patients were lost to follow-up and the remaining 9 (39.1%) patients died. Patients survived for a median period of 28 weeks (range, 2 to 64 weeks). The nodule recurred in 6 (26.1%) patients after complete excision. Sister Mary Joseph's nodule of the umbilicus is not rare in our environment and often represents manifestation of a variety of advanced intra-abdominal malignancies. The majority of the patients present at a late stage and many with distant metastases. The patient's survival is very short leading to a poor outcome. Early detection of primary cancer at an early stage may improve the prognosis