Pulse transit time: a new approach to haemodynamic monitoring in obstetric spinal anaesthesia

Part of the Portfolio Thesis by Geoffrey H. Sharwood-Smith: The inferior vena caval compression theory of hypotension in obstetric spinal anaesthesia: studies in normal and preeclamptic pregnancy, a literature review and revision of fundamental concepts, available at http://hdl.handle.net/10023/1815Original abstract presented at the Obstetric Anaesthetisits' Association congress 2002, Nottingham, 9-10 May.Postprin

Pulse transit time confirms altered response to spinal anaesthesia in pregnancy induced hypertension

Poster presented at the International Society for the Study of Hypertension in Pregnancy (ISSHP)Congress, Toronto 2002.Part of the Portfolio Thesis by Geoffrey H. Sharwood-Smith: The inferior vena caval compression theory of hypotension in obstetric spinal anaesthesia: studies in normal and preeclamptic pregnancy, a literature review and revision of fundamental concepts, available at http://hdl.handle.net/10023/1815Postprin

Introducing NICE guidelines for intravenous fluid therapy into a district general hospital

Peer reviewedPublisher PD

Dimensions of Sedimentary Lithotopes and Taxonomies of Fishes

The size of subgroups among larger taxonomic units, as measured by the number of taxa within them, is a metric of fundamental importance to the appreciation of causes of change in biodiversity in both time and space. Central to such evaluations is an understanding of the expected and observed variation in the numbers and sizes of groups comprising various taxonomic levels. Here we show that numbers of fish taxa within subdivisions (memberships) of any supertaxon in a Linnaean taxonomy are virtually identical to areas of patches of like sediment (lithotopes) that are distributed across various depositional surfaces. Both sedimentary surfaces and Linnaean taxonomies are closely approximated by functions that generally describe random divisions of geographic and/or shape-space. We describe a ‘broken plate’ model for taxonomic membership that is akin to Robert MacArthur’s (1957) classical ‘broken stick’ model for abundance distributions, where species abundances in an ecosystem are described by an exponential function of abundance (segment length) frequencies reflecting the random subdivision of resources. In a taxonomic context, the broken plate presumes that the amount of morphospace realized at any taxonomic level is proportional to the numbers of subtaxa of which it is comprised. A hypothetical transect across the morphospace associated with any higher taxon would comprise a ‘broken stick’, or exponential, distribution of square roots of the number of contained subtaxa. Taxonomic membership (occupied morphospace) within the higher taxon is therefore randomly partitioned among subtaxa, analogous to the sizes of fragments of the broken plate. Thus, just as the broken stick distribution is well-described using only the length of the stick and the number of segments into which it is broken, the partitioning of taxa into subtaxa within any supertaxon is random and adequately described using only the number of taxa and the number of subtaxa into which they are partitioned. Such ‘broken plate’ functions yield excellent agreement for membership partitioning among classes, orders, families, and genera of fishes. Quantification across all taxonomic levels provides several insights related to the biodiversity of this important group: (1) Membership of taxonomic groups of fishes is self-similar among all levels of Linnaean division (e.g., families per order, genera per family, species per genus) and is almost entirely independent of levels of taxonomic separation between groups being considered, with an average of seven to eight members within any taxonomic group. (2) The ‘broken plate’ representation implies that divisions within one taxonomic level are independent of all other divisions; a similar partitioning of species among genera belonging to both diverse and depauperate families supports the supposition that little ‘memory’ exists between levels of taxonomic membership. (3) Special explanations for the generation of apparently extreme polytype may be largely unnecessary; taxonomic diversities expected from the ‘broken plate’ model suggest that observed disparity in numbers of fish species comprising many clades is no greater or less than one would expect from a random fragmentation of morphospace.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/171083/1/UMMZ MP 209 Vol. 3 12.23.pdf-1Description of UMMZ MP 209 Vol. 3 12.23.pdf : Main articleSEL

The outcome and cost-effectiveness of nurse-led care in the community for people with rheumatoid arthritis:a non-randomised pragmatic study

To determine the outcome and cost-effectiveness of nurse-led care in the community for people with rheumatoid arthritis (RA)

Effect of regional topography and hydrology on the lacustrine isotopic record of Miocene paleoclimate in the Rocky Mountains

Oxygen isotopic compositions of upper Miocene (9.2 m.y.) lacustrine limestone from northwestern Wyoming range from -21.5 to -35.2% (PDB) and are the lightest yet reported for a non-marine carbonate sequence. These values require that lake water was greatly depleted in 18O relative to modern meteoric precipitation and indicate that most inflow was sourced as meltwater from glaciers in the adjacent Gros Ventre range. Assessment of climatic factors influencing the isotopic composition of global meteoric water indicates either that nearly all of Miocene precipitaaion in the southern Rocky Mountains was derived from large lake systems in the Snake River Plain and northern Great Basin to the west, or that Gros Ventre catchment elevations were up to 2300 m higher than at present. Because erosion rates in modern alpine regions suggest that subaerial denudation could only account for up to 1200 m of post-Miocene elevation reduction, any additional lowering must reflect the influence of post-Laramide epeirogeny during Basin and Range extentional tectonism. Lacustrine isotopic data therefore provide boundary conditions on the timing and magnitude of changes in late Cenozoic paleoclimate, topography, hydrology, and tectonism in the western Wyoming portion of the Rocky Mountains.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30925/1/0000595.pd

quasiharmonic equations of state for dynamically-stabilized soft-mode materials

We introduce a method for treating soft modes within the analytical framework of the quasiharmonic equation of state. The corresponding double-well energy-displacement relation is fitted to a functional form that is harmonic in both the low- and high-energy limits. Using density-functional calculations and statistical physics, we apply the quasiharmonic methodology to solid periclase. We predict the existence of a B1--B2 phase transition at high pressures and temperatures

Mapping the disease-specific LupusQoL to the SF-6D

Purpose To derive a mapping algorithm to predict SF-6D utility scores from the non-preference-based LupusQoL and test the performance of the developed algorithm on a separate independent validation data set. Method LupusQoL and SF-6D data were collected from 320 patients with systemic lupus erythematosus (SLE) attending routine rheumatology outpatient appointments at seven centres in the UK. Ordinary least squares (OLS) regression was used to estimate models of increasing complexity in order to predict individuals’ SF-6D utility scores from their responses to the LupusQoL questionnaire. Model performance was judged on predictive ability through the size and pattern of prediction errors generated. The performance of the selected model was externally validated on an independent data set containing 113 female SLE patients who had again completed both the LupusQoL and SF-36 questionnaires. Results Four of the eight LupusQoL domains (physical health, pain, emotional health, and fatigue) were selected as dependent variables in the final model. Overall model fit was good, with R2 0.7219, MAE 0.0557, and RMSE 0.0706 when applied to the estimation data set, and R2 0.7431, MAE 0.0528, and RMSE 0.0663 when applied to the validation sample. Conclusion This study provides a method by which health state utility values can be estimated from patient responses to the non-preference-based LupusQoL, generalisable beyond the data set upon which it was estimated. Despite concerns over the use of OLS to develop mapping algorithms, we find this method to be suitable in this case due to the normality of the SF-6D data

Eradication of chronic myeloid leukemia stem cells: a novel mathematical model predicts no therapeutic benefit of adding G-CSF to imatinib

Imatinib mesylate induces complete cytogenetic responses in patients with chronic myeloid leukemia (CML), yet many patients have detectable BCR-ABL transcripts in peripheral blood even after prolonged therapy. Bone marrow studies have shown that this residual disease resides within the stem cell compartment. Quiescence of leukemic stem cells has been suggested as a mechanism conferring insensitivity to imatinib, and exposure to the Granulocyte-Colony Stimulating Factor (G-CSF), together with imatinib, has led to a significant reduction in leukemic stem cells in vitro. In this paper, we design a novel mathematical model of stem cell quiescence to investigate the treatment response to imatinib and G-CSF. We find that the addition of G-CSF to an imatinib treatment protocol leads to observable effects only if the majority of leukemic stem cells are quiescent; otherwise it does not modulate the leukemic cell burden. The latter scenario is in agreement with clinical findings in a pilot study administering imatinib continuously or intermittently, with or without G-CSF (GIMI trial). Furthermore, our model predicts that the addition of G-CSF leads to a higher risk of resistance since it increases the production of cycling leukemic stem cells. Although the pilot study did not include enough patients to draw any conclusion with statistical significance, there were more cases of progression in the experimental arms as compared to continuous imatinib. Our results suggest that the additional use of G-CSF may be detrimental to patients in the clinic