University of British Columbia

About: University of British Columbia is a education organization based out in Vancouver, British Columbia, Canada. It is known for research contribution in the topics: Population & Health care. The organization has 89939 authors who have published 209679 publications receiving 9226862 citations. The organization is also known as: UBC & The University of British Columbia.

Changes in forced expiratory volume in 1 second over time in copd

Abstract: A b s t r ac t We analyzed the changes in FEV1 after administration of a bronchodilator over a 3-year period in 2163 patients. A random-coefficient model was used to evaluate possible predictors of both FEV1 levels and their changes over time. Results The mean (±SE) rate of change in FEV 1 was a decline of 33±2 ml per year, with sig - nificant variation among the patients studied. The between-patient standard devia- tion for the rate of decline was 59 ml per year. Over the 3-year study period, 38% of patients had an estimated decline in FEV1 of more than 40 ml per year, 31% had a decline of 21 to 40 ml per year, 23% had a change in FEV1 that ranged from a de- crease of 20 ml per year to an increase of 20 ml per year, and 8% had an increase of more than 20 ml per year. The mean rate of decline in FEV1 was 21±4 ml per year greater in current smokers than in current nonsmokers, 13±4 ml per year greater in patients with emphysema than in those without emphysema, and 17±4 ml per year greater in patients with bronchodilator reversibility than in those without reversibility. Conclusions The rate of change in FEV1 among patients with COPD is highly variable, with increased rates of decline among current smokers, patients with bronchodilator reversibility, and patients with emphysema. (Funded by GlaxoSmithKline; ECLIPSE ClinicalTrials.gov number, NCT00292552.)

PyClone: statistical inference of clonal population structure in cancer

Abstract: The hierarchical Bayesian model identifies and quantifies clonal populations in tumors from deep-sequenced somatic mutations.

Perspective: the pace of modern life: measuring rates of contemporary microevolution.

Abstract: We evaluate methods for measuring and specifying rates of microevolution in the wild, with particular regard to studies of contemporary, often deemed "rapid," evolution. A considerable amount of ambiguity and inconsistency persists within the field, and we provide a number of suggestions that should improve study design, inference, and clarity of presentation. (1) Some studies measure change over time within a population (allochronic) and others measure the difference between two populations that had a common ancestor in the past (synchronic). Allochronic studies can be used to estimate rates of "evolution," whereas synchronic studies more appropriately estimate rates of "divergence." Rates of divergence may range from a small fraction to many times the actual evolutionary rates in the component populations. (2) Some studies measure change using individuals captured from the wild, whereas others measure differences after rearing in a common environment. The first type of study can be used to specify "phenotypic" rates and the later "genetic" rates. (3) The most commonly used evolutionary rate metric, the darwin, has a number of theoretical shortcomings. Studies of microevolution would benefit from specifying rates in standard deviations per generation, the haldane. (4) Evolutionary rates are typically specified without an indication of their precision. Readily available methods for specifying confidence intervals and statistical significance (regression, bootstrapping, randomization) should be implemented. (5) Microevolutionists should strive to accumulate time series, which can reveal temporal shifts in the rate of evolution and can be used to identify evolutionary patterns. (6) Evolutionary rates provide a convenient way to compare the tempo of evolution across studies, traits, taxa, and time scales, but such comparisons are subject to varying degrees of confidence. Comparisons across different time scales are particularly tenuous. (7) A number of multivariate rate measures exist, but considerable theoretical development is required before their utility can be determined. We encourage the continued investigation of evolutionary rates because the information they provide is relevant to a wide range of theoretical and practical issues.

Sealing Plant Surfaces: Cuticular Wax Formation by Epidermal Cells

Abstract: The vital importance of plant surface wax in protecting tissue from environmental stresses is reflected in the huge commitment of epidermal cells to cuticle formation. During cuticle deposition, a massive flux of lipids occurs from the sites of lipid synthesis in the plastid and the endoplasmic reticulum to the plant surface. Recent genetic studies in Arabidopsis have improved our understanding of fatty acid elongation and of the subsequent modification of the elongated products into primary alcohols, wax esters, secondary alcohols, and ketones, shedding light on the enzymes involved in these pathways. In contrast, the biosynthesis of alkanes is still poorly understood, as are the mechanisms of wax transport from the site of biosynthesis to the cuticle. Currently, nothing is known about wax trafficking from the endoplasmic reticulum to the plasma membrane, or about translocation through the cell wall to the cuticle. However, a first breakthrough toward an understanding of wax export recently came with the discovery of ATP binding cassette (ABC) transporters that are involved in releasing wax from the plasma membrane into the apoplast. An overview of our present knowledge of wax biosynthesis and transport and the regulation of these processes during cuticle assembly is presented, including the evidence for coordination of cutin polyester and wax production.

Preliminary evaluation of a scheme for grading the gross morphology of the human intervertebral disc

Abstract: A five-category grading scheme for assessing the gross morphology of midsagittal sections of the human lumbar intervertebral disc was developed. The ability of three observers to categorize a series of 68 discs with a wide spectrum of morphologies established the comprehensiveness of the classificat