No description available.

Estimation procedures and optimal designs for estimation of the individual parameters and of the global parameters are discussed under various conditions of prior knowledge. The extension to nonlinear parametrization of the response function ís based on the asymptotical validity of the results for the linear parametrization. For the case where the error variance and the dispersion matrix are unknown, an iterative estimation procedure is suggested. An example based on dental plaque pH profiles demonstrates the improvement that is achieved (a) through using the optimal design or a design that ís close to the optimal, and (b) through taking into account prior information. (author's abstract) / Series: Forschungsberichte / Institut für Statistik

<p>Dental plaque is the most important etiological factor of periodontal diseases. Mechanical plaque control is the most effective way in preventing periodontal diseases. Chemical plaque control methods (such as mouthrinses) have been recommended to be used because of some drawbacks in the mechanical methods in some areas of the dentition (such as interproximal areas). But are these mouthrinses really effective in those areas? The aim of this study was to compare the effectiveness of Essential Oils mouthrinse (Listerine) on plaque formation in interproximal areas with Chlorhexidine and Sterile water.</p>

A large number of studies have reported on the association between the obligate intracellular bacterium, Chlamydia pneumoniae and atherosclerosis. These studies suggest that C. pneumoniae may potentially play a role in the atherosclerotic process, as not all the current atherosclerotic risk factors account for the resulting complications, such as angina, myocardial infarction, heart failure and stroke. The research presented in this thesis analysed whether there are any reliable markers of chronic C. pneumoniae vascular infection, including chlamydial sero-prevalence as defined by two commercial serological tests, detection of C. pneumoniae DNA in the peripheral circulation, the presence or absence of risk factors and symptomatic status. The presence of the bacterium in atherosclerotic carotid specimens was diagnosed directly using a C. pneumoniae-specific polymerase chain reaction (PCR) and a genus-specific immunofluorescent (IF) assay. Eighteen of the 54 (33%) carotid artery diseased (CAD) specimens were positive for the presence of C. pneumoniae DNA by PCR detection, whereas the IF assay detected only six positive samples. PCR analysis found that only two of 43 (5%) patients had C. pneumoniae DNA present within their peripheral blood mononuclear cell (PBMC) fraction. Chlamydial antibodies were detected by Focus microimmunofluorescence and/or Medac recombinant enzyme-linked immunosorbert assay (rELISA) in 56% (24/43) of CAD patients tested. Traditional risk factors, symptomatic status, antigen detection and PCR-based detection of C. pneumoniae in PBMCs, all failed to correlate with the presence of a chlamydial vascular infection. In conclusion, the existing non-invasive diagnostic tests (serology and peripheral blood-based PCR detection) are inefficient for diagnosing a vascular Chlamydia infection, suggesting that a different chlamydial antigen should be tested targeted to identify a chronic C. pneumoniae infection in CAD patients. Given the observation that numerous previously published studies have detected C. pneumoniae in atherosclerotic arterial tissue, yet at widely different detection rates (0% to 100%), it was clear that the location and quantity of clinical specimen could directly affect the detection rate. Previous reports have not used a standard and validated procedure for sampling arterial specimens for C. pneumoniae DNA. The inconsistent detection rates of chlamydial DNA in atherosclerotic plaque are a result of low concentration and irregular distribution of the bacterium, as reported in this study. Our research concluded that a minimum of 15 (30ìm-thick) sections should be analysed by PCR to minimize these sampling variables and obtain a 95% chance of detecting all true C. pneumoniae-positive samples. All previous studies may have under estimated the prevalence of C. pneumoniae, as stringent sampling and repeat testing of the bacterium is required to minimise false-negative results. An interesting finding was that C. pneumoniae DNA was present in all 10 atherosclerotic arteries, although extensive sampling of the carotid was crucial for detection. The third area of research examined the question of possible strain differences between C. pneumoniae isolates infecting human atherosclerotic carotid arteries. Whole genome sequencing as well as specific gene typing suggests that there is relatively little genetic variation in human isolates of C. pneumoniae. To date, there has been little genomic analysis of strains from human cardiovascular sites. We analysed the genotypes of C. pneumoniae present in human atherosclerotic carotid plaque and found several polymorphisms in the variable domain-4 (VD4) region of the outer membrane protein-A (ompA) gene and the intergenic region between the ygeD and uridine kinase (ygeD-urk) genes. Our research identified four different genotypes of C. pneumoniae in human atherosclerotic carotid arteries, including an isolate that appears genetically identical to a strain previously detected in koalas. Two genotypes of C. pneumoniae were present in both human carotid specimens and koala PBMC fractions, suggesting that these genotypes of C. pneumoniae may be capable of crossing the host barrier. The study showed that diversity exists in both the ompAVD4 gene and the ygeD-urk intergenic region enabling fine-detailed differentiation between five different genotypes found in respiratory and/or vascular C. pneumoniae isolates. The importance of the diversity of C. pneumoniae isolates in its role in atherogenesis needs to be further studied.

No abstract available

Zugl.: Bochum, Univ., Diss., 2005

Diss. (sammanfattning) Umeå : Univ., 2006. / Härtill 5 uppsatser.

Thesis (M.D.S.)--University of Adelaide, Dental School, 2000. / Includes bibliographical references (leaves 127-141).

Thesis (M.S.)--University of Michigan, 1986.

Diss. (sammanfattning) Umeå : Umeå universitet, 2008. / Härtill 5 uppsatser.