Introduction: Clostridium difficile infection (CDI) is a common hospital-acquired infection and a financial burden on the healthcare system. There is a need to reduce its impact on patients and the entire health system. More accurate estimates of the financial impact of CDI will assist hospitals in creating better CDI reduction strategies with limited resources. Previous research has not sufficiently accounted for the skewed nature of hospital cost data, baseline patient mortality risk, and the time-varying nature of CDI. Objective: We conducted a retrospective cohort study to estimate the cost impact of hospital-acquired CDI from the hospital perspective, using a number of analytical approaches. Method: We used clinical and administrative data for inpatients treated at The Ottawa Hospital to construct an analytical data set. Our primary outcome was direct costs and our primary exposure was hospital-acquired CDI. We performed the following analyses: Ordinary least square regression and generalized linear regression as time-fixed methods, and Kaplan-Meier survival curve and Cox regression models as time-varying methods. Results: A total of 49,888 admissions were included in this study (mean (SD) age of 64.6 ± 17.8 years, median (IQR) baseline mortality risk of 0.04 (0.01-0.14)). 360 (0.73%) patients developed CDI. Estimates of incremental cost due to CDI were substantially higher when using time-fixed methods than time-varying methods. Using methods that appropriately account for the time-varying nature of the exposure, the estimated incremental cost due to CDI was $8,997 per patient. In contrast, estimates from time-fixed methods ranged from $49,150 to $55,962: about a six fold difference. Conclusion: Estimates of hospital costs are strongly influenced by the time-varying nature of CDI as well as baseline mortality risk. If studies do not account for these factors, it is likely that the impact of hospital-acquired CDI will be overestimated.

Historically, there has been limited empirical study of children whose parents have suffered an acquired brain injury. This is despite the fact that both clinical opinion and qualitative study suggest that these children may represent a population at risk for a variety of emotional and behavioral problems. The current study set out to evaluate the overall psychosocial functioning of a small subset of children whose parents had suffered an acquired brain injury (TBI, stroke) and who were in the more chronic phase of recovery (average time post-injury = 3.3 years). Factors that have been proposed to impact child psychosocial functioning in this population were assessed including the neurobehavioral profile of the parent with an injury, parental depression, and the child’s report of the parental relationship. In all, ten children (average age = 13 years) from seven families with parental ABI were evaluated both on a comprehensive measure of child psychosocial functioning (BASC-2) and a series of qualitative measures. As compared to a normative sample, results of quantitative analyses suggest a group of children not experiencing general clinical distress. In fact, statistical analyses suggest resiliency in the current sample as compared to normative data. At the individual level, two of the children in the sample evidenced behavior that warrants further clinical evaluation, though this finding may be on par with the base rates of clinical distress seen in the general population. Qualitative analyses provide a richer understanding of the experiences of these children and their families and suggest avenues for further empirical evaluation. Results are presented in the context of other studies to date. Recommendations for clinicians and researchers based on current findings are provided. / Graduate / 0622 / rlillie@uvic.ca

This dissertation is a compendium of multiple research papers that, together, address two main objectives. The first objective and primary research question is to determine whether or not, through a procedure of independent component analysis (ICA)-based data mining, volume-domain validation, and source volume estimation, it is possible to construct a meaningful, objective, and informative model of brain activity from scalpacquired EEG data. Given that a methodology to construct such a model can be created, the secondary objective and research question investigated is whether or not the sources derived from the EEG data can be used to construct a model of complex brain function associated with the spatial navigation and the virtual Morris Water Task (vMWT). The assumptions of the signal and noise characteristics of scalp-acquired EEG data were discussed in the context of what is currently known about functional brain activity to identify appropriate characteristics by which to separate the activities comprising EEG data into parts. A new EEG analysis methodology was developed using both synthetic and real EEG data that encompasses novel algorithms for (1) data-mining of the EEG to obtain the activities of individual areas of the brain, (2) anatomical modeling of brain sources that provides information about the 3-dimensional volumes from which each of the activities separated from the EEG originates, and (3) validation of data mining results to determine if a source activity found via the data-mining step originates from a distinct modular unit inside the head or if it is an artefact. The methodology incorporating the algorithms developed was demonstrated for EEG data collected from study participants while they navigated a computer-based virtual maze environment. The brain activities of participants were meaningfully depicted via brain source volume estimation and representation of the activity relationships of multiple areas of the brain. A case study was used to demonstrate the analysis methodology as applied to the EEG of an individual person. In a second study, a group EEG dataset was investigated and activity relationships between areas of the brain for participants of the group study were individually depicted to show how brain activities of individuals can be compared to the group. The results presented in this dissertation support the conclusion that it is feasible to use ICA-based data mining to construct a physiological model of coordinated parts of the brain related to the vMWT from scalp-recorded EEG data. The methodology was successful in creating an objective and informative model of brain activity from EEG data. Furthermore, the evidence presented indicates that this methodology can be used to provide meaningful evaluation of the brain activities of individual persons and to make comparisons of individual persons against a group. In sum, the main contributions of this body of work are 5 fold. The technical contributions are: (1) a new data mining algorithm tailored for EEG, (2) an EEG component validation algorithm that identifies noise components via their poor representation in a head model, (3) a volume estimation algorithm that estimates the region in the brain from which each source waveform found via data mining originates, (4) a new procedure to study brain activities associated with spatial navigation. The main contribution of this work to the understanding of brain function is (5) evidence of specific functional systems within the brain that are used while persons participate in the vMWT paradigm (Livingstone and Skelton, 2007) examining spatial navigation. / Graduate / 0541 / 0622 / 0623

iv The present work describes the evaluation of the value of polymerase chain reaction in diagnosis of pneumonia caused by the most common three bacterial pathogens / Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis from sputum of patients with community acquired pneumonia admitted to The Department of Pulmonary Diseases of Gulhane Military Medical Academy. In this study, 107 sputa from 142 patients with suspected community acquired pneumonia were used to survey the causative agents. Identification of the pathogens was performed by sputum Gram stain and conventional microbiological methods. Polymerase chain reaction was performed to investigate the presence of S.pneumoniae, H.influenzae, and M.catarrhalis for the same sputum samples as well. PCR products were processed by electrophoresis on 2% agarose gels with visualization of the amplicon with ethidium bromide and UV illumination. The 33 of 107 samples were positive in cultures and 67 in PCR. S.pneumoniae (48.5%) was the most common etiologic agent as to PCR analysis. The incidences of H.influenzae and M.catarrhalis were determined as 18.6%, and 4.7% respectively. The incidence of S.pneumoniae in patients with CAP and control group individuals were almost the same. The sputum PCR positives were higher than those reported carriage rates for these three microorganisms. 9 of 107 patients with PCR-positive had evidence of infection with pathogens other than S.pneumoniae. The results indicated that some of the PCR results were false positive due to oropharyngeal contamination. PCR testing of sputum samples for diagnosing pneumococcal pneumonia is unable to distinguish colonization from infection in some circumstances. To distinguish the colonization from infection, sputum Gram stain should be applied to the sputum specimens. Because of being faster and easier, PCR looks like becoming more reliable technique by the using of valid specimens from patients with community-acquired pneumonia if supported by quantitative techniques.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2007. / Härtill 5 uppsatser.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2005. / Härtill 4 uppsatser.

Diss. (sammanfattning) Stockholm : Karol. inst., 2002. / Härtill 6 uppsatser.

Diss. (sammanfattning) Stockholm : Karol inst., 2003. / Härtill 5 uppsatser.

Diss. (sammanfattning) Uppsala : Uppsala universitet, 2006. / Härtill 4 uppsatser.

Thesis (Ph. D.)--University of Washington, 1992. / Vita. Includes bibliographical references (leaves [211]-226).