Fungal speciation using quantitative polymerase chain reaction (QPCR) in patients with and without chronic rhinosinusitis.

Objectives/hypothesisThe objectives of this study were to determine the mycology of the middle meatus using an endoscopically guided brush sampling technique and polymerase chain reaction laboratory processing of nasal mucous; to compare the mycology of the middle meatus in patients with sinus disease with subjects without sinus disease; to compare the responses on two standardized quality-of-life survey forms between patients with and without sinusitis; and to determine whether the presence of fungi in the middle meatus correlates with responses on these data sets.Study designThe authors conducted a single-blind, prospective, cross-sectional study.MethodsPatients with sinus disease and a control group without sinus disease were enrolled in the study. A disease-specific, validated Sinonasal Outcomes Test survey (SNOT-20) was completed by the subjects and a generalized validated Medical Outcomes Short Form 36 Survey (SF-36) was also completed. An endoscopically guided brush sampling of nasal mucous was obtained from the middle meatus. Fungal specific quantitative polymerase chain reaction (QPCR) was performed on the obtained sample to identify one of 82 different species of fungus in the laboratory. Statistical analysis was used to categorize the recovered fungal DNA and to crossreference this information with the outcomes surveys.ResultsThe fungal recovery rate in the study was 45.9% in patients with sinus disease and 45.9% in control subjects. Patients with chronic rhinosinusitis had a mean SNOT-20 score of 1.80 versus the control group mean score of 0.77 (P < .0001). SF-36 data similarly showed a statistically significant difference between diseased and control populations with controls scoring a mean of 80.37 and patients with chronic rhinosinusitis scoring a mean of 69.35 for a P value of .02. However, no statistical significance could be ascribed to the presence or absence of fungi recovered, the type of fungi recovered, or the possible impact of fungi on the quality-of-life survey results.ConclusionThe recovery rate of fungi from the middle meatus of patients with chronic rhinosinusitis and a control population without chronic rhinosinusitis is 45.9% using QPCR techniques. No direct causation with regard to fungal species or presence was proven; however, a species grouping for future studies is proposed based on trends in this data and other reports. Disease-specific outcomes surveys revealed a statistically significant difference between the two groups

Maximum Skew-Symmetric Flows and Matchings

The maximum integer skew-symmetric flow problem (MSFP) generalizes both the maximum flow and maximum matching problems. It was introduced by Tutte in terms of self-conjugate flows in antisymmetrical digraphs. He showed that for these objects there are natural analogs of classical theoretical results on usual network flows, such as the flow decomposition, augmenting path, and max-flow min-cut theorems. We give unified and shorter proofs for those theoretical results. We then extend to MSFP the shortest augmenting path method of Edmonds and Karp and the blocking flow method of Dinits, obtaining algorithms with similar time bounds in general case. Moreover, in the cases of unit arc capacities and unit ``node capacities'' the blocking skew-symmetric flow algorithm has time bounds similar to those established in Even and Tarjan (1975) and Karzanov (1973) for Dinits' algorithm. In particular, this implies an algorithm for finding a maximum matching in a nonbipartite graph in $O(\sqrt{n}m)$ time, which matches the time bound for the algorithm of Micali and Vazirani. Finally, extending a clique compression technique of Feder and Motwani to particular skew-symmetric graphs, we speed up the implied maximum matching algorithm to run in $O(\sqrt{n}m\log(n^2/m)/\log{n})$ time, improving the best known bound for dense nonbipartite graphs. Also other theoretical and algorithmic results on skew-symmetric flows and their applications are presented.Comment: 35 pages, 3 figures, to appear in Mathematical Programming, minor stylistic corrections and shortenings to the original versio

Perceptual thresholds for the effects of room modes as a function of modal decay

Room modes cause audible artefacts in listening environments. Modal control approaches have emerged in scientific literature over the years and, often, their performance is measured by criteria that may be perceptually unfounded. Previous research has shown modal decay as a key perceptual factor in detecting modal effects. In this work, perceptual thresholds for the effects of modes as a function of modal decay have been measured in the region between 32Hz and 250Hz. A test methodology has been developed to include modal interaction and temporal masking from musical events, which are important aspects in recreating an ecologically valid test regime. This method has been deployed in addition to artificial test stimuli traditionally used in psychometric studies, which provide unmasked, absolute thresholds. For artificial stimuli, thresholds decrease monotonically from 0.9 seconds at 32 Hz to 0.17 seconds at 200 Hz, with a knee at 63 Hz. For music stimuli, thresholds decrease monotonically from 0.51 seconds at 63 Hz to 0.12 seconds at 250 Hz. Perceptual thresholds are shown to be dependent on frequency and to a much lesser extent on level. Results presented here define absolute and practical thresholds, which are useful as perceptually relevant optimization targets for modal control methods

Use of human autologous chondrocytes and mesenchymal progenitor cells in cartilage repair techniques

Due to articular cartilage's limited intrinsic repair potential, the treatment of cartilage damage in the younger patient provides a major challenge. The relative failure of many synthetic solutions, has led to the growing interest in the development of cell-based repair systems. In general two strategies have been considered. The first approach is to enhance the intrinsic healing capacity of both the cartilage and subchondral bone through the release of mesenchymal progenitor cells, however, to date, these techniques have only led to fibrocartilaginous repairs, which lack long term durability. An alternative approach involves the use of tissue engineering strategies to elicit a biological repair. The most commonly used practice in the clinical setting is Autologous Chondrocyte Implantation (ACI). This thesis presents a review of the literature in the subject of cartilage repair, looks at the cell sources available to develop repair systems and investigates factors that might influence these cells. In this study, an in vitro system was used to promote the chondrogenic potential of these cells allowing for study of some of the factors responsible for this complex process. Human mesenchymal progenitor cells were isolated by self selection through monolayer culture and induced to chondrogenic differentiation in a pellet model using culture in a chemically defined serum-free medium. The effects of dynamic compression on freshly isolated and passaged human chondrocytes was also studied. Results suggest that a defined medium, containing TGFp, is necessary to induce the re-expression of a differentiated chondrocyte phenotype and the subsequent stimulation of GAG and type II collagen. This thesis highlights a number of areas where knowledge could be improved in relation to the biomechanical events that take place in the repair of cartilage defects and a theory is proposed to explain why marrow techniques lead to a fibrocartilage repair. Andrew Julian Goldberg 2006 Interdisciplinary Research Centre, Institute of Orthopaedics, Royal Free & University College Medical School, London, UK. Medical Engineering Division and IRC in Biomedical Materials, Department of Engineering, Queen Mary, University of London, Mile End Road London, E1 4NS. Submitted in fulfillment of the requirements for the degree of MD