Determination of oxygen saturation compared to a prescribed target range using continuous pulse oximetry in acutely unwell medical patients.

BACKGROUND: Both inadequate and excessive administration of oxygen to acutely unwell patients results in risk of harm. Guidelines recommend titration of oxygen to achieve a target oxygen saturation (SpO2) range. Information regarding whether this is being achieved is limited. METHODS: In this two-centre non-interventional study we used continuous pulse oximetry in acutely unwell medical patients over a 24-h period to determine the proportion of time spent with SpO2 within the prescribed target range and whether this is influenced by the target range, age, care in a high-dependency area and the number of oxygen adjustments. RESULTS: Eighty participants were included in the analysis. The mean (SD) proportion of time spent in target range was 55.6% (23.6), this was lower in those with a reduced hypercapnic target range (88-92% or below) compared to those with a range of 92-96%; difference - 13.1% (95% CI - 3.0 to - 23.2), P = 0.012. The proportion of time spent above range was 16.2% (22.9); this was higher in those with a reduced hypercapnic range; difference 21.6% (31.4 to 12), P < 0.001. The proportion of time below range was 28.4% (25.2); there was no difference between target ranges. The proportion of time spent in range was higher for those in a high dependency area in the multivariate model; difference 15.5% (95% CI 2.3 to 28.7), P = 0.02. CONCLUSIONS: Medical patients receiving oxygen in a ward setting spend significant periods of time with SpO2 both above and below the prescribed target range while receiving oxygen therapy.

Did the house mouse (Mus musculus L.) shape the evolutionary trajectory of wheat (Triticum aestivum L.)?

Wheat (Triticum aestivum L.) is one of the most successful domesticated plant species in the world. The majority of wheat carries mutations in the Puroindoline genes that result in a hard kernel phenotype. An evolutionary explanation, or selective advantage, for the spread and persistence of these hard kernel mutations has yet to be established. Here, we demonstrate that the house mouse (Mus musculus L.) exerts a pronounced feeding preference for soft over hard kernels. When allele frequencies ranged from 0.5 to 0.009, mouse predation increased the hard allele frequency as much as 10-fold. Studies involving a single hard kernel mixed with ∼1000 soft kernels failed to recover the mutant kernel. Nevertheless, the study clearly demonstrates that the house mouse could have played a role in the evolution of wheat, and therefore the cultural trajectory of humankind.

Identification of novel Wilms' tumor suppressor gene target genes implicated in kidney development.

The Wilms' tumor suppressor gene (WT1) encodes a zinc finger transcription factor that is vital during development of several organs including metanephric kidneys. Despite the critical regulatory role of WT1, the pathways and mechanisms by which WT1 orchestrates development remain elusive. To identify WT1 target genes, we performed a genome-wide expression profiling analysis in cells expressing inducible WT1. We identified a number of direct WT1 target genes, including the epidermal growth factor (EGF)-family ligands epiregulin and HB-EGF, the chemokine CX3CL1, and the transcription factors SLUG and JUNB. The target genes were validated using quantitative reverse transcriptase-polymerase chain reaction, small interfering RNA knockdowns, chromatin immunoprecipitation, and luciferase reporter analyses. Immunohistochemistry of fetal kidneys confirmed that a number of the WT1 target genes had overlapping expression patterns with the highly restricted spatiotemporal expression of WT1. Finally, using an in vitro embryonic kidney culture assay, we found that the addition of recombinant epiregulin, amphiregulin, CX3CL1, and interleukin-11 significantly enhanced ureteric bud branching morphogenesis. Our genome-wide screen implicates WT1 in the transcriptional regulation of the EGF-family of growth factors as well as the CX3CL1 chemokine during nephrogenesis.

Fluid mechanics produces conflicting, constraints during olfactory navigation of blue crabs, Callinectes sapidus.

Foraging blue crabs must respond to fluid forces imposed on their body while acquiring useful chemical signals from turbulent odor plumes. This study examines how blue crabs manage these simultaneous demands. The drag force, and hence the cost of locomotion, experienced by blue crabs is shown to be a function of the body orientation angle relative to the flow. Rather than adopting a fixed orientation that minimizes the drag, blue crabs decrease their relative angle (increase drag) when odor is present in low speed flow, while assuming a drag-minimizing posture under other conditions. The motivation for crabs to adopt an orientation with larger drag appears to relate to their ability to acquire chemical signal information for odor tracking. In particular, when orienting at a smaller angle relative to the flow direction, more concentrated odor filaments arrive at the antennules to mediate upstream movement, allowing a more useful bilateral comparison between the appendage chemosensors to be made. Blue crabs respond to conflicting demands by weighting the degree of drag minimization in proportion to the potential magnitude of the drag cost and the potential benefit of acquiring chemosensory cues. Higher flow velocity magnifies the locomotory cost of a high drag posture, thus in swift flows crabs minimize drag and sacrifice their ability to acquire olfactory cues.

Cumulative trauma disorders in the upper extremities: reliability of the postural and repetitive risk-factors index.

OBJECTIVE: This study addresses test-retest reliability of the Postural and Repetitive Risk-Factors Index (PRRI) for work-related upper body injuries. This assessment was developed by the present authors. DESIGN: A repeated measures design was used to assess the test-retest reliability of a videotaped work-site assessment of subjects' movements. SUBJECTS: Ten heavy users of video display terminals (VDTs) from a local banking industry participated in the study. SETTING: The 10 subjects' movements were videotaped for 2 hours on each of 2 separate days, while working on-site at their VDTs. MAIN OUTCOME MEASURE: The videotaped assessment, which utilized known postural risk factors for developing musculoskeletal disorder, pain, and discomfort in heavy VDT users (ie, repetitiveness, awkward and static postures, and contraction time), was called the PRRI. The videotaped movement assessments were subsequently analyzed in 15-minute sessions (five sessions per 2-hour videotape, which produced a total of 10 sessions over the 2 testing days), and each session was chosen randomly from the videotape. The subjects' movements were given a postural risk score according to the criteria in the PRRI. Each subject was therefore tested a total of 10 times (ie, 10 sessions), over two days. The maximum PRRI score for both sides of the body was 216 points. RESULTS: Reliability coefficients (RCs) for the PRRI scores were calculated, and the reliability of any one session met the minimum criterion for excellent reliability, which was .75. A two-way analysis of variance (ANOVA) confirmed that there was no statistically significant difference between sessions (p < .05). Calculations using the standard error of measurement (SEM) indicated that an individual tested once, on one day and with a PRRI score of 25, required a change of at least 8 points in order to be confident that a true change in score had occurred. The significant results from the reliability tests indicated that the PRRI was a reliable measurement tool that could be used by occupational health practitioners on the job site.