With the financial assistance from two donors, we have established a neurodegenerative disease brain bank at the University of Calgary. At autopsy, tissues from anatomically specific regions are frozen in liquid nitrogen vapour and stored in small, bar-coded cryovials. Cases include patients with dementia, movement disorders, demyelinating diseases, and normal controls. We prepare additional FFPE blocks for diagnosis or banking. Sampling includes all major areas of cortex and most subcortical structures. All brains, including “normal” controls, are characterized with a basic set of stains and major classification schemata are used for Alzheimer and Lewy body diseases. These tissues are available to investigators with IRB-approved research on human tissuesControl tissue is important in the study of age-associated neurodegeneration. We preserve tissues from areas of brain that either are severely or minimally affected by neurodegeneration (e.g. in Alzheimer disease, Brodmann areas 9 and 17, respectively). In our “normal” aging cohort, which includes patients with no described neurodegenerative diseases, we find frequent evidence of low-stage Alzheimer or Lewy body related pathological changes. We also find relatively frequent small vessel disease, which in part relates to our preferential selection of patient’s who died suddenly.In preliminary studies, we have examined amyloid plaque structure with confocal microscopy using beta-sheet sensitive dyes and have studied the distribution of different chaperones in normal brain.

The purpose of this study was twofold: first, to determine whether the five-year results of hip resurfacing arthroplasty (HRA) in Canada justified the continued use of HRA; and second, to identify whether greater refinement of patient selection was warranted.This was a retrospective cohort study that involved a review of 2773 HRAs performed between January 2001 and December 2008 at 11 Canadian centres. Cox's proportional hazards models were used to analyse the predictors of failure of HRA. Kaplan-Meier survival analysis was performed to predict the cumulative survival rate at five years. The factors analysed included age, gender, body mass index, pre-operative hip pathology, surgeon's experience, surgical approach, implant sizes and implant types. The most common modes of failure were also analysed.The 2773 HRAs were undertaken in 2450 patients: 2127 in men and 646 in women. The mean age at operation was 50.5 years (SD 8.72; 18 to 82) and mean follow-up was 3.4 years (SD 2.1; 2.0 to 10.1). At the last follow-up a total of 101 HRAs (3.6%) required revision. Using revision for all causes of failure as the endpoint, Kaplan-Meier survival analysis showed a cumulative survival of 96.4% (95% confidence interval (CI) 96.1 to 96.9) at five years. With regard to gender, the five-year overall survival was 97.4% in men (95% CI 97.1 to 97.7) and 93.6% in women (95% CI 92.6 to 94.6). Female gender, smaller femoral components, specific implant types and a diagnosis of childhood hip problems were associated with higher rates of failure. The most common cause of failure was fracture of the femoral neck, followed by loosening of the femoral component.The failure rates of HRA at five years justify the ongoing use of this technique in men. Female gender is an independent predictor of failure, and a higher failure rate at five years in women leads the authors to recommend this technique only in exceptional circumstances for women.

ABSTRACT In previous work (E. E. Smith, D. G. Buckley, Z. Wu, C. Saenphimmachack, L. R. Hoffman, D. A. D'Argenio, S. I. Miller, B. W. Ramsey, D. P. Speert, S. M. Moskowitz, J. L. Burns, R. Kaul, and M. V. Olson, Proc. Natl. Acad. Sci. USA 103: 8487-8492, 2006) it was shown that Pseudomonas aeruginosa undergoes intense genetic adaptation during chronic respiratory infection (CRI) in cystic fibrosis (CF) patients. We used the same collection of isolates to explore the role of hypermutation in this process, since one of the hallmarks of CRI is the high prevalence of DNA mismatch repair (MMR) system-deficient mutator strains. The presence of mutations in 34 genes (many of them positively linked to adaptation in CF patients) in the study collection of 90 P. aeruginosa isolates obtained longitudinally from 29 CF patients was not homogeneous; on the contrary, mutations were significantly concentrated in the mutator lineages, which represented 17% of the isolates (87% MMR deficient). While sequential nonmutator lineages acquired a median of only 0.25 mutation per year of infection, mutator lineages accumulated more than 3 mutations per year. On the whole-genome scale, data for the first fully sequenced late CF isolate, which was also shown to be an MMR-deficient mutator, also support these findings. Moreover, for the first time the predicted amplification of mutator populations due to hitchhiking with adaptive mutations in the course of natural human infections is clearly documented. Interestingly, increased accumulation of mutations in mutator lineages was not a consequence of overrepresentation of mutations in genes involved in antimicrobial resistance, the only adaptive trait linked so far to hypermutation in CF patients, demonstrating that hypermutation also plays a major role in P. aeruginosa genome evolution and adaptation during CRI.

The opportunistic pathogen Pseudomonas aeruginosa undergoes genetic change during chronic airway infection of cystic fibrosis (CF) patients. One common change is a mutation inactivating lasR, which encodes a transcriptional regulator that responds to a homoserine lactone signal to activate expression of acute virulence factors. Colonies of lasR mutants visibly accumulated the iridescent intercellular signal 4-hydroxy-2-heptylquinoline. Using this colony phenotype, we identified P. aeruginosa lasR mutants that emerged in the airway of a CF patient early during chronic infection, and during growth in the laboratory on a rich medium. The lasR loss-of-function mutations in these strains conferred a growth advantage with particular carbon and nitrogen sources, including amino acids, in part due to increased expression of the catabolic pathway regulator CbrB. This growth phenotype could contribute to selection of lasR mutants both on rich medium and within the CF airway, supporting a key role for bacterial metabolic adaptation during chronic infection. Inactivation of lasR also resulted in increased beta-lactamase activity that increased tolerance to ceftazidime, a widely used beta-lactam antibiotic. Loss of LasR function may represent a marker of an early stage in chronic infection of the CF airway with clinical implications for antibiotic resistance and disease progression.

At the heart of many business successes is the ability to manage the inherent risk brought on by the difference in the prices charged and the costs incurred to provide goods or services. Previous work has illustrated that this price-cost risk management can be viewed in geometric terms; gauging risk amounts to assessing an ab- stract distance. The minimization of this distance then involves solving a nonlinear optimization problem. This paper discusses the tactical problems associated with implementing price-cost risk management and the ability to measure the performance of risk mitigation approaches. Sampling and tractability issues associated with the nonlinear optimization problem are discussed. Specific to telecommunications environments, the price-cost optimization problem relates to a more standard knapsack optimization problem.

In many human infections, hosts and pathogens coexist for years or decades. Important examples include HIV, herpes viruses, tuberculosis, leprosy, and malaria. With the exception of intensively studied viral infections such as HIV/AIDs, little is known about the extent to which the clonal expansion that occurs during long-term infection by pathogens involves important genetic adaptations. We report here a detailed, whole-genome analysis of one such infection, that of a cystic fibrosis (CF) patient by the opportunistic bacterial pathogen Pseudomonas aeruginosa. The bacteria underwent numerous genetic adaptations during 8 years of infection, as evidenced by a positive-selection signal across the genome and an overwhelming signal in specific genes, several of which are mutated during the course of most CF infections. Of particular interest is our finding that virulence factors that are required for the initiation of acute infections are often selected against during chronic infections. It is apparent that the genotypes of the P. aeruginosa strains present in advanced CF infections differ systematically from those of "wild-type" P. aeruginosa and that these differences may offer new opportunities for treatment of this chronic disease.

ABSTRACT Pyoverdine is the primary siderophore of the gram-negative bacterium Pseudomonas aeruginosa . The pyoverdine region was recently identified as the most divergent locus alignable between strains in the P. aeruginosa genome. Here we report the nucleotide sequence and analysis of more than 50 kb in the pyoverdine region from nine strains of P. aeruginosa . There are three divergent sequence types in the pyoverdine region, which correspond to the three structural types of pyoverdine. The pyoverdine outer membrane receptor fpvA may be driving diversity at the locus: it is the most divergent alignable gene in the region, is the only gene that showed substantial intratype variation that did not appear to be generated by recombination, and shows evidence of positive selection. The hypothetical membrane protein PA2403 also shows evidence of positive selection; residues on one side of the membrane after protein folding are under positive selection. R′, previously identified as a type IV strain, is clearly derived from a type III strain via a 3.4-kb deletion which removes one amino acid from the pyoverdine side chain peptide. This deletion represents a natural modification of the product of a nonribosomal peptide synthetase enzyme, whose consequences are predictive from the DNA sequence. There is also linkage disequilibrium between the pyoverdine region and pvdY , a pyoverdine gene separated by 30 kb from the pyoverdine region. The pyoverdine region shows evidence of horizontal transfer; we propose that some alleles in the region were introduced from other soil bacteria and have been subsequently maintained by diversifying selection.

The telecommunications network transition scheduling problem combines the difficulties of routing problems and manufacturing problems. When telecommunications requirements transition from one provider or to- pology to another, coordination of activities involving many different sites must occur and the activities at any given site must follow a particular ordering. A transition sub-problem of particular interest involves the tran- sition of hierarchical telecommunications networks. This paper provides insight into the strategies to employ for the transition of hierarchical telecommunications networks; specifically, the objectives to consider for making strategic decisions as well as techniques to handle constraints unique to hierarchical networks.

ABSTRACT Whole-genome shotgun sequencing was used to study the sequence variation of three Pseudomonas aeruginosa isolates, two from clonal infections of cystic fibrosis patients and one from an aquatic environment, relative to the genomic sequence of reference strain PAO1. The majority of the PAO1 genome is represented in these strains; however, at least three prominent islands of PAO1-specific sequence are apparent. Conversely, ∼10% of the sequencing reads derived from each isolate fail to align with the PAO1 backbone. While average sequence variation among all strains is roughly 0.5%, regions of pronounced differences were evident in whole-genome scans of nucleotide diversity. We analyzed two such divergent loci, the pyoverdine and O-antigen biosynthesis regions, by complete resequencing. A thorough analysis of isolates collected over time from one of the cystic fibrosis patients revealed independent mutations resulting in the loss of O-antigen synthesis alternating with a mucoid phenotype. Overall, we conclude that most of the PAO1 genome represents a core P. aeruginosa backbone sequence while the strains addressed in this study possess additional genetic material that accounts for at least 10% of their genomes. Approximately half of these additional sequences are novel.

This paper studies the telecommunications network transition scheduling problem, which concerns the transition of services from an existing telecommunications network to a new telecommunications network. This problem is a particular instance of the classical scheduling problem. Both optimal and non-optimal approaches used to solve the classical scheduling problem are described. A telecommunications network transition scheduling problem is formulated, and a sample problem using the optimal and non-optimal approaches for the classical scheduling problem is solved. For the telecommunications network transition scheduling problem, the non-optimal approaches provide reasonable solutions. We describe a tool we have developed for the analysis of the telecommunications network transition scheduling problem. An example is presented to demonstrate the capabilities of the tool.

The microanatomy of the lingual nerve in the third molar area was studied. Twenty-two pairs of lingual nerves were dissected from human cadavers. The area of each nerve adjacent to the third molar was identified, cut, serially sectioned, and stained with hematoxylin and eosin. Nerve cell bodies were found within the structure of 40 of the 44 individual nerves (90.91%). There were two patterns of organization of the nerve cell bodies: isolated nerve cell bodies and ganglion-like clusters of nerve cell bodies. Because of the proximity of the submandibular ganglion, it can be inferred that these cell bodies are parasympathetic in function. The presence of nerve cell bodies in the lingual nerve in the third molar region could have possible clinical ramifications.