999 resultados para early diagnostics


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Cerebral microangiopathy (CMA) has been associated with executive dysfunction and fronto-parietal neural network disruption. Advances in magnetic resonance imaging allow more detailed analyses of gray (e.g., voxel-based morphometry-VBM) and white matter (e.g., diffusion tensor imaging-DTI) than traditional visual rating scales. The current study investigated patients with early CMA and healthy control subjects with all three approaches. Neuropsychological assessment focused on executive functions, the cognitive domain most discussed in CMA. The DTI and age-related white matter changes rating scales revealed convergent results showing widespread white matter changes in early CMA. Correlations were found in frontal and parietal areas exclusively with speeded, but not with speed-corrected executive measures. The VBM analyses showed reduced gray matter in frontal areas. All three approaches confirmed the hypothesized fronto-parietal network disruption in early CMA. Innovative methods (DTI) converged with results from conventional methods (visual rating) while allowing greater spatial and tissue accuracy. They are thus valid additions to the analysis of neural correlates of cognitive dysfunction. We found a clear distinction between speeded and nonspeeded executive measures in relationship to imaging parameters. Cognitive slowing is related to disease severity in early CMA and therefore important for early diagnostics.

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O Cancro da mama é uma doença cuja incidência tem vindo a aumentar de ano para ano e além disso é responsável por um grande número de mortes em todo mundo. De modo a combater esta doença têm sido propostos e utilizados biomarcadores tumorais que permitem o diagnóstico precoce, o acompanhamento do tratamento e/ou a orientação do tipo tratamento a adotar. Atualmente, os biomarcadores circulantes no sangue periférico recomendados pela Associação Americana de Oncologia Clinica (ASCO) para monitorizar os pacientes durante o tratamento são o cancer antigen 15-3 (CA 15-3), o cancer antigen 27.29 (CA 27.29) e o cancer embryobic antigen (CEA). Neste trabalho foi desenvolvido um sensor eletroquímico (voltamétrico) para monitorizar o cancro da mama através da análise do biomarcador CA 15-3. Inicialmente realizou-se o estudo da adsorção da proteína na superfície do elétrodo para compreender o comportamento do sensor para diferentes concentrações. De seguida, estudaram-se três polímeros (poliaminofenol, polifenol e polifenilenodiamina) e selecionou-se o poliaminofenol como o polímero a utilizar, pois possuía a melhor percentagem de alteração de sinal. Após a seleção do polímero, este foi depositado na superfície do elétrodo por eletropolimerização, formando um filme polimérico molecularmente impresso (MIP) à volta da proteína (molde). Posteriormente, foram analisados cinco solventes (água, mistura de dodecil sulfato de sódio e ácido acético, ácido oxálico, guanidina e proteinase K) e o ácido oxálico revelou ser mais eficaz na extração da proteína. Por último, procedeu-se à caraterização do sensor e analisou-se a resposta analítica para diferentes concentrações de CA 15-3 revelando diferenças claras entre o NIP (polímero não impresso) e o MIP.

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Bauchspeicheldrüsenkrebs ist die vierthäufigste Krebstodesursache in Deutschland. Durch die tiefe Lage des Organs im Körperinneren und das späte Auftreten von Symptomen erfolgt die Diagnose meist zu einem sehr späten Zeitpunkt, zu dem eine Resektion des Tumors in 80% der Fälle nicht mehr möglich ist. Die Hälfte der Patienten verstirbt bereits im ersten Jahr nach Diagnosestellung. Nach heutiger Erkenntnis entwickeln sich Adenokarzinome der Bauchspeicheldrüse über schrittweise histologische Veränderungen, die sogenannten PanIN Läsionen (pancreatic intraepithelial neoplasia). Bis heute fehlen jedoch klinisch einsetzbare Parameter für die Früherkennung des Karzinoms und seiner Vorstufen. Bisher ist nicht vollständig geklärt, welche molekularen Veränderungen hierbei eine wesentliche Rolle spielen. Das Ziel der vorliegenden Arbeit ist, die molekular- und zytogenetische Mutationsinzidenz und -Sequenz im Verlauf der neoplastischen Progression in der PanIN-Sequenz aufzuklären. Unter Anwendung der Fluoreszenz-in-situ-Hybridisierung (FISH) wird weiterführend die Frage beantwortet, ob sich der Nachweis von zytogenetischen Veränderungen in Zellen, die endoskopisch aus dem Pankreassekret gewonnen wurden, als neuartiger Ansatz für eine Frühdiagnostik nutzen lassen. Die molekulargenetischen Analysen zeigen, dass die PanIN-Läsionen aus Geweben mit chronischer Pankreatitis denen aus Geweben mit Karzinomen gleichzusetzen sind. Veränderungen in der Anzahl einzelner Chromosomen, sowie Basenmutationen finden sich bereits in den frühesten Gangläsionen. Die diffuse Verteilung von Genmutationen lässt einen mutagenen Feldeffekt vermuten, in welchem endogene (z.B. Pankreasenzyme, oxidativer Stress) und/oder exogene (z.B. Nikotin, Alkohol) Noxen auf verschiedene Pankreasgänge während einer langen Zeit einwirken. Auf der Basis der erhaltenen Daten kann angenommen werden, dass die prä-neoplastischen Läsionen in Geweben mit chronischer Pankreatitis eine Progression durchlaufen, in der sich sporadische Defekte wie Basenmutationen und Mitosefehler (Aneuplodien) akkumulieren. Die biologische Relevanz für die Tumorentstehung sollte jedoch immer im klinischen Kontext betrachtet werden. In Kombination mit weiteren Parametern (z.B. Alter, Dauer der Pankreatitis) könnte dies eine Möglichkeit bieten, das Risiko für die Entstehung eines Karzinoms individuell zu bestimmen und somit Patienten frühzeitig genug vor der Manifestation eines Tumors einer (Teil-)Resektion des Organs zuzuführen.

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Diagnostics is based on the characterization of mechanical system condition and allows early detection of a possible fault. Signal processing is an approach widely used in diagnostics, since it allows directly characterizing the state of the system. Several types of advanced signal processing techniques have been proposed in the last decades and added to more conventional ones. Seldom, these techniques are able to consider non-stationary operations. Diagnostics of roller bearings is not an exception of this framework. In this paper, a new vibration signal processing tool, able to perform roller bearing diagnostics in whatever working condition and noise level, is developed on the basis of two data-adaptive techniques as Empirical Mode Decomposition (EMD), Minimum Entropy Deconvolution (MED), coupled by means of the mathematics related to the Hilbert transform. The effectiveness of the new signal processing tool is proven by means of experimental data measured in a test-rig that employs high power industrial size components.

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Failures on rolling element bearings usually originate from cracks that are detectable even in their early stage of propogation by properly analyzing vibration signals measured in the proximity of the bearing. Due to micro-slipping in the roller-races contact, damage-induced vibration signals belong to the family of quasi-periodic signals with a strong second order cyclostationary component. Cyclic coherence and its integrated form are widely considered as the most suitable tools for bearing fault diagnostics and their theoretical bases have been already consolidated. This paper presents how to correctly set the parameters of the cyclostationary analysis tool to be implemented in an automatable algorithm. In the first part of the paper some general guidelines are provided for the specific application. These considerations are further verified, applying cyclostationary tools to data collected in an experimental campaign on a specific test-rig.

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Oral diseases, or stomatognathic diseases, denote the diseases of the mouth (“stoma”) and jaw (“gnath”). Dental caries and periodontal diseases have been traditionally considered as the most important global oral health burdens. It is important to note that in oral diagnostics, the greatest challenges are determining the clinical utility of potential biomarkers for screening (in asymptomatic people), predicting the early onset of disease (prognostic tests), and evaluating the disease activity and the efficacy of therapy through innovative diagnostic tests. An oral diagnostic test, in principle, should provide valuable information for differential diagnosis, localization of disease, and severity of infection. This information can then be incorporated by the physician when planning treatments and will provide means for assessing the effectiveness of therapy.

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Sepsis is associated with a systemic inflammatory response. It is characterised by an early proinflammatory response and followed by a state of immunosuppression. In order to improve the outcome of patients with infection and sepsis, novel therapies that influence the systemic inflammatory response are being developed and utilised. Thus, an accurate and early diagnosis of infection and evaluation of immune state are crucial. In this thesis, various markers of systemic inflammation were studied with respect to enhancing the diagnostics of infection and of predicting outcome in patients with suspected community-acquired infection. A total of 1092 acutely ill patients admitted to a university hospital medical emergency department were evaluated, and 531 patients with a suspicion of community-acquired infection were included for the analysis. Markers of systemic inflammation were determined from a blood sample obtained simultaneously with a blood culture sample on admission to hospital. Levels of phagocyte CD11b/CD18 and CD14 expression were measured by whole blood flow cytometry. Concentrations of soluble CD14, interleukin (IL)-8, and soluble IL-2 receptor α (sIL-2Rα) were determined by ELISA, those of sIL-2R, IL-6, and IL-8 by a chemiluminescent immunoassay, that of procalcitonin by immunoluminometric assay, and that of C-reactive protein by immunoturbidimetric assay. Clinical data were collected retrospectively from the medical records. No marker of systemic inflammation, neither CRP, PCT, IL-6, IL-8, nor sIL-2R predicted bacteraemia better than did the clinical signs of infection, i.e., the presence of infectious focus or fever or both. IL-6 and PCT had the highest positive likelihood ratios to identify patients with hidden community-acquired infection. However, the use of a single marker failed to detect all patients with infection. A combination of markers including a fast-responding reactant (CD11b expression), a later-peaking reactant (CRP), and a reactant originating from inflamed tissues (IL-8) detected all patients with infection. The majority of patients (86.5%) with possible but not verified infection showed levels exceeding at least one cut-off limit of combination, supporting the view that infection was the cause of their acute illness. The 28-day mortality of patients with community-acquired infection was low (3.4%). On admission to hospital, the low expression of cell-associated lipopolysaccharide receptor CD14 (mCD14) was predictive for 28-day mortality. In the patients with severe forms of community-acquired infection, namely pneumonia and sepsis, high levels of soluble CD14 alone did not predict mortality, but a high sCD14 level measured simultaneously with a low mCD14 raised the possibility of poor prognosis. In conclusion, to further enhance the diagnostics of hidden community-acquired infection, a combination of inflammatory markers is useful; 28-day mortality is associated with low levels of mCD14 expression at an early phase of the disease.

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Dengue is a mosquito-borne viral disease caused by the four dengue virus serotypes (DENV-1-4) and is currently considered as the most important arthropod-borne viral disease in the world. Nearly half of the human population lives in risk areas, and 50-100 million infections occur yearly according to World Health Organization. The disease can vary from a mild febrile disease to severe haemorrhagic fever and shock. A secondary infection with heterologous serotype increases the risk for severe disease outcome. During the last three decades the impact of dengue has dramatically increased in the endemic areas including the tropics and subtropics of the world. The current situation with massive epidemics of severe disease forms has been associated with socio-ecological changes that have increased the transmission and enabled the co-circulation of different serotypes. Consequently, an increase of dengue has also been observed in travelers visiting these areas. Currently approximately 30 cases are diagnosed yearly in Finnish travelers. In travelers dengue is rarely a life-threatening disease, however in the current study, a fatality was documented in a young Finnish patient who experienced a prolonged primary dengue infection. To improve particularly early laboratory diagnostics, a novel real-time RT-PCR method was developed for the detection of DENV-1-4 RNA based on TaqMan chemistry. The method was shown to be sensitive and specific for detecting DENV RNA and suitable for diagnostic use. The newly developed real-time RT-PCR was compared to other available early diagnostic methods including IgM and NS1 antigen detection using a panel of selected patient samples. The results suggest that the best diagnostic rates are achieved by a combination of IgM with RNA or NS1 detection. The dengue virus strains studied here included the first DENV strains isolated from serum samples of Finnish travelers collected in 2000-2005. The results of sequence analysis demonstrated that the 11 isolates included all four DENV serotypes and presented a global sample of DENV strains from different geographical areas including Asia, Africa and South America. In the present study sequence analysis was also carried out for a collection of 23 novel DENV-2 isolates from Venezuelan patients collected in 1999-2005. The Venezuelan DENV-2 exclusively represented the American-Asian genotype, suggesting that no foreign DENV-2 lineages have recently been introduced to the country. The results also suggest that the DENV-2 viruses detected earlier from Venezuela have been maintained in the area where they have evolved into several lineages. This is in contrast to the pattern observed in some other dengue endemic areas, where introductions of novel virus types and lineages are frequently detected.

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Hypokinesia, rigidity, tremor, and postural instability are the cardinal symptoms of Parkinson s disease (PD). Since these symptoms are not specific to PD the diagnosis may be uncertain in early PD. Etiology and pathogenesis of PD remain unclear. There is no neuroprotective therapy. Genetic findings are expected to reveal metabolic routes in PD pathogenesis and thereby eventually lead to therapeutic innovations. In this thesis, we first aimed to study the usefulness and accuracy of 123I-b-CIT SPECT in the diagnosis of PD in a consecutive clinic-based material including various movement disorders. We subsequently a genetic project to identify genetic risk factors for sporadic PD using a candidate gene approach in a case-control setting including 147 sporadic PD patients and 137 spouse controls. Dopamine transporter imaging by 123I-b-CIT SPECT could distinguish PD from essential tremor, drug-induced parkinsonism, dystonia and psychogenic parkinsonism. However, b-CIT uptake in Parkinson plus syndromes (PSP and multiple system atrophy) and dementia with Lewy bodies was not significantly different from PD. 123I-b-CIT SPECT could not reliably differentiate PD from vascular parkinsonism. 123I-b-CIT SPECT was 100% sensitive and specific in the diagnosis of PD in patients younger than 55 years but less specific in older patients, due to differential distribution of the above conditions in the younger and older age groups. 123I-b-CIT SPECT correlated with symptoms and detected bilateral nigrostriatal defect in patients whose PD was still in unilateral stage. Thus, in addition to as a differential diagnostic aid, 123I-b-CIT SPECT may be used to detect PD early, even pre-symptomatically in at-risk individuals. 123I-b-CIT SPECT was used to aid in the collection of patients to the genetic studies. In the genetic part of this thesis we found an association between PD and a polymorphic CAG-repeat in POLG1 gene encoding the catalytic subunit of mitochondrial polymerase gamma. The CAG-repeat encodes a polyglutamine tract (polyQ), the two most common lengths of which are 10Q (86-90%) and 11Q. In our Finnish material, the rarer non-10Q or non-11Q length variants (6Q-9Q, 12Q-14Q, 4R+9Q) were more frequent in patients than in spouse controls (10% vs. 3.5 %, p=0.003), or population controls (p=0.001). Therefore, we performed a replication study in 652 North American PD patients and 292 controls. Non-10/11Q alleles were more common in the US PD patients compared to the controls but the difference did not reach statistical significance (p=0.07). This larger data suggested our original definition of variant length allele might need reconsideration. Most previous studies on phenotypic effects of POLG1 polyQ have defined 10Q as the only normal allele. Non-10Q alleles were significantly more common in patients compared to the controls (17.3% vs. 12.3 %, p= 0.005). This association between non-10Q length variants and PD remained significant when compared to a larger set of 1541 literature controls (p=0.00005). In conclusion, POLG1 polyQ alleles other than 10Q may predispose to PD. We did not find association between PD and parkin or DJ-1, genes underlying autosomal recessive parkinsonism. The functional Val158Met polymorphism, which affects the catalytic effect of COMT enzyme, and another coding polymorphism in COMT were not associated with PD in our patient material. The APOE e2/3/4 polymorphism modifies risk for Alzheimer s disease and prognosis of for example brain trauma. APOE promoter and enhancer polymorphisms 219G/T and +113G/C, and APOE e3 haplotypes, have also been shown to modify the risk of Alzheimer s disease but not reported in PD. No association was found between PD and APOE e2/3/4 polymorphism, the promoter or enhancer polymorphisms, or the e3 haplotypes.

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Childhood-onset mitochondrial diseases comprise a heterogeneous group of disorders, which may manifest with almost any symptom and affect any tissue or organ. Due to challenging diagnostics, most children still lack a specific aetiological diagnosis. The aim of this thesis was to find molecular causes for childhood-onset mitochondrial disorders in Finland. We identified the underlying cause for 25 children, and found three new diseases, which had not been diagnosed in Finland before. These diseases caused severe progressive infantile-onset encephalomyopathies, and were due to defects in mitochondrial DNA (mtDNA) maintenance. Furthermore, the thesis provides the molecular background of Finnish patients with ‘leukoencephalopathy with brain stem and spinal cord involvement and elevated brain lactate’ (LBSL). A new phenotype was identified to be due to mutations in Twinkle, resembling ‘infantile onset spinocerebellar ataxia’ (IOSCA). These mutations caused mtDNA depletion in the liver, thus confirming the essential role of Twinkle in mtDNA maintenance, and expanding the molecular background of mtDNA depletion syndromes. The major aetiology for infantile mitochondrial myopathy in Finland was discovered to be due to mutations in thymidine kinase 2 (TK2). A novel mutation with Finnish ancestry was identified, and a genotype-phenotype correlation with mutation-specific distribution of tissue involvement was found, thus proving that deficient TK2 may cause multi-tissue depletion and impair neuronal function. This work established the molecular diagnosis and advanced the knowledge of phenotypes among paediatric patients with polymerase gamma (POLG) mutations. The patients showed severe early-onset encephalopathy with intractable epilepsy. POLG mutations are not a prevalent cause of children’s ataxias, although ataxia is a major presenting symptom among adults. Our findings indicate that POLG mutations should be investigated even if typical MRI, histochemical or biochemical abnormalities are lacking. LBSL patients showed considerable variation in phenotype despite identical mutations. A common, most likely European, ancestry, and a relative high carrier frequency of these mutations in Finland were discovered; suggesting that LBSL may be a quite common leukoencephalopathy in other populations as well. The results suggest that MRI findings are so unique that the diagnosis of LBSL is possible to make without genetic studies. This thesis work has resulted in identification of new mitochondrial disorders in Finland, enhancing the understanding of the clinical variability and the importance of tissue-specificity of these disorders. In addition to providing specific diagnosis to the patients, these findings give light to the underlying pathogenetic mechanisms of childhood-onset mitochondrial disorders.

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Fatigue fracture is an overuse injury commonly encountered in military and sports medicine, and known to relate to intensive or recently intensified physical activity. Bone responds to increased stress by enhanced remodeling. If physical stress exceeds bone s capability to remodel, accumulation of microfractures can lead to bone fatigue and stress fracture. Clinical diagnosis of stress fractures is complex and based on patient s anamnesis and radiological imaging. Bone stress fractures are mostly low-risk injuries, healing well after non-operative management, yet, occurring in high-risk areas, stress fractures can progress to displacement, often necessitating surgical treatment and resulting in prolonged morbidity. In the current study, the role of vitamin D as a predisposing factor for fatigue fractures was assessed using serum 25OHD level as the index. The average serum 25OHD concentration was significantly lower in conscripts with fatigue fracture than in controls. Evaluating TRACP-5b bone resorption marker as indicator of fatigue fractures, patients with elevated serum TRACP-5b levels had eight times higher probability of sustaining a stress fracture than controls. Among the 154 patients with exercise induced anterior lower leg pain and no previous findings on plain radiography, MRI revealed a total of 143 bone stress injuries in 86 patients. In 99% of the cases, injuries were in the tibia, 57% in the distal third of the tibial shaft. In patients with injury, forty-nine (57%) patients exhibited bilateral stress injuries. In a 20-year follow-up, the incidence of femoral neck fatigue fractures prior to the Finnish Defence Forces new regimen in 1986 addressing prevention of these fractures was 20.8/100,000, but rose to 53.2/100,000 afterwards, a significant 2.6-fold increase. In nineteen subjects with displaced femoral neck fatigue fractures, ten early local complications (in first postoperative year) were evident, and after the first postoperative year, osteonecrosis of the femoral head in six and osteoarthritis of the hip in thirteen patients were found. It seems likely that low vitamin D levels are related to fatigue fractures, and that an increasing trend exists between TRACP-5b bone resorption marker elevation and fatigue fracture incidence. Though seldom detected by plain radiography, fatigue fractures often underlie unclear lower leg stress-related pain occurring in the distal parts of the tibia. Femoral neck fatigue fractures, when displaced, lead to long-term morbidity in a high percentage of patients, whereas, when non-displaced, they do not predispose patients to subsequent adverse complications. Importantly, an educational intervention can diminish the incidence of fracture displacement by enhancing awareness and providing instructions for earlier diagnosis of fatigue fractures.

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Technical or contaminated ethanol products are sometimes ingested either accidentally or on purpose. Typical misused products are black-market liquor and automotive products, e.g., windshield washer fluids. In addition to less toxic solvents, these liquids may contain the deadly methanol. Symptoms of even lethal solvent poisoning are often non-specific at the early stage. The present series of studies was carried out to develop a method for solvent intoxication breath diagnostics to speed up the diagnosis procedure conventionally based on blood tests. Especially in the case of methanol ingestion, the analysis method should be sufficiently sensitive and accurate to determine the presence of even small amounts of methanol from the mixture of ethanol and other less-toxic components. In addition to the studies on the FT-IR method, the Dräger 7110 evidential breath analyzer was examined to determine its ability to reveal a coexisting toxic solvent. An industrial Fourier transform infrared analyzer was modified for breath testing. The sample cell fittings were widened and the cell size reduced in order to get an alveolar sample directly from a single exhalation. The performance and the feasibility of the Gasmet FT-IR analyzer were tested in clinical settings and in the laboratory. Actual human breath screening studies were carried out with healthy volunteers, inebriated homeless men, emergency room patients and methanol-intoxicated patients. A number of the breath analysis results were compared to blood test results in order to approximate the blood-breath relationship. In the laboratory experiments, the analytical performance of the Gasmet FT-IR analyzer and Dräger 7110 evidential breath analyzer was evaluated by means of artificial samples resembling exhaled breath. The investigations demonstrated that a successful breath ethanol analysis by Dräger 7110 evidential breath analyzer could exclude any significant methanol intoxication. In contrast, the device did not detect very high levels of acetone, 1-propanol and 2-propanol in simulated breath. The Dräger 7110 evidential breath ethanol analyzer was not equipped to recognize the interfering component. According to the studies the Gasmet FT-IR analyzer was adequately sensitive, selective and accurate for solvent intoxication diagnostics. In addition to diagnostics, the fast breath solvent analysis proved feasible for controlling the ethanol and methanol concentration during haemodialysis treatment. Because of the simplicity of the sampling and analysis procedure, non-laboratory personnel, such as police officers or social workers, could also operate the analyzer for screening purposes.

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The work in this thesis concerns the advanced development of polymeric membranes of two types; pervaporation and lateral-flow. The former produced from a solution casting method and the latter from a phase separation. All membranes were produced from casting lacquers. Early research centred on the development of viable membranes. This led to a supported polymer blend pervaporation membrane. Selective layer: plasticized 4:1 mass ratio sodium-alginate: poly(vinyl-alcohol) polymer blend. Using this membrane, pervaporation separation of ethanol/water mixtures was carefully monitored as a function of film thickness and time. Contrary to literature expectations, these films showed increased selectivity and decreased flux as film thickness was reduced. It is argued that morphology and structure of the polymer blend changes with thickness and that these changes define membrane efficiency. Mixed matrix membrane development was done using spherical, discreet, size-monodisperse mesoporous silica particles of 1.8 - 2μm diameter, with pore diameters of ~1.8 nm were incorporated into a poly(vinyl alcohol) [PVA] matrix. Inclusion of silica benefitted pervaporation performance for the dehydration of ethanol, improving flux and selectivity throughout in all but the highest silica content samples. Early lateral-flow membrane research produced a membrane from a basic lacquer composition required for phase inversion; polymer, solvent and non-solvent. Results showed that bringing lacquers to cloud point benefits both the pore structure and skin layers of the membranes. Advancement of this work showed that incorporation of ethanol as a mesosolvent into the lacquer effectively enhances membrane pore structure resulting in an improvement in lateral flow rates of the final membranes. This project details the formation mechanics of pervaporation and lateral-flow membranes and how these can be controlled. The principle methods of control can be applied to the formation of any other flat sheet polymer membranes, opening many avenues of future membrane research and industrial application.