Useful applications of earth-oriented satellites - Systems for remote-sensing information and distribution, panel 8

Problems and potential use of data gathered by remote sensing from satellites or aircraf

The determinants of transverse tubular volume in resting skeletal muscle.

The transverse tubular (t)-system of skeletal muscle couples sarcolemmal electrical excitation with contraction deep within the fibre. Exercise, pathology and the composition of the extracellular fluid (ECF) can alter t-system volume (t-volume). T-volume changes are thought to contribute to fatigue, rhabdomyolysis and disruption of excitation-contraction coupling. However, mechanisms that underlie t-volume changes are poorly understood. A multicompartment, history-independent computer model of rat skeletal muscle was developed to define the minimum conditions for t-volume stability. It was found that the t-system tends to swell due to net ionic fluxes from the ECF across the access resistance. However, a stable t-volume is possible when this is offset by a net efflux from the t-system to the cell and thence to the ECF, forming a net ion cycle ECF→t-system→sarcoplasm→ECF that ultimately depends on Na(+)/K(+)-ATPase activity. Membrane properties that maximize this circuit flux decrease t-volume, including PNa(t) > PNa(s), PK(t) < PK(s) and N(t) < N(s) [P, permeability; N, Na(+)/K(+)-ATPase density; (t), t-system membrane; (s), sarcolemma]. Hydrostatic pressures, fixed charges and/or osmoles in the t-system can influence the magnitude of t-volume changes that result from alterations in this circuit flux. Using a parameter set derived from literature values where possible, this novel theory of t-volume was tested against data from previous experiments where t-volume was measured during manipulations of ECF composition. Predicted t-volume changes correlated satisfactorily. The present work provides a robust, unifying theoretical framework for understanding the determinants of t-volume.JAF was supported by a David Phillips Fellowship (BB/FO23863/1) awarded by the Biotechnology and Biological Sciences Research Council (UK). JS was supported by the Agency for Science, Technology and Research (Singapore) and a Caius Medical Association summer studentship from Gonville and Caius College, University of Cambridge.This is the final version. It was first published by Wiley at http://onlinelibrary.wiley.com/doi/10.1113/jphysiol.2014.281170/abstract

Improved left ventricular contractility with cool temperature hemodialysis

Improved left ventricular contractility with cool temperature hemodialysis. Cool temperature dialysis (CTD) has been shown to sharply decrease the frequency of intradialytic hemodialysis hypotension, but the mechanism of this hemodynamic protection is unknown. Therefore, we performed two-dimensional echocardiographic studies of left ventricular contractility in six stable hemodialysis patients before and after hemodialysis at 37°C (RTD) and 35°C (CTD). Left ventricular function was assessed by plotting the rate-corrected velocity of circumferential fiber shortening (Vcfc) against end-systolic wall stress (σes) at four different levels of afterload. Linear regression was used to calculate Vcfc at a common afterload of 50 g/cm2. Changes in weight and dialysis parameters were similar following RTD and CTD. Mean arterial pressure and heart rate did not change significantly following RTD or CTD. The Vcfc – σes relation was shifted upward in each patient after CTD, indicating increased contractility as compared to RTD or pre-dialysis baseline. Pre-dialysis Vcfc at an afterload of 50 g/cm2 was similar during RTD and CTD (0.94 ± 0.24 circ/sec vs. 0.92 ± 0.22 circ/sec). Post-dialysis Vcfc at an afterload of 50 g/cm2 was significantly higher for CTD than for RTD (1.13 ± 0.29 circ/sec vs. 0.98 ± 0.30 circ/sec, P = 0.0004). Thus, cool temperature dialysis increases left ventricular contractility in hemodialysis patients, which may be a potential mechanism whereby hemodynamic tolerance to the dialysis procedure is improved

Reduced LIMK2 expression in colorectal cancer reflects its role in limiting stem cell proliferation

Objective: Colorectal cancer (CRC) is a major contributor to cancer mortality and morbidity. LIM kinase 2 (LIMK2) promotes tumour cell invasion and metastasis. The objectives of this study were to determine how LIMK2 expression is associated with CRC progression and patient outcome, and to use genetically modified Drosophila and mice to determine how LIMK2 deletion affects gastrointestinal stem cell regulation and tumour development.&lt;p&gt;&lt;/p&gt; Design: LIMK2 expression and activity were measured by immunostaining tumours from CRC-prone mice, human CRC cell lines and 650 human tumours. LIMK knockdown in Drosophila or Limk2 deletion in mice allowed for assessment of their contributions to gastrointestinal stem cell homeostasis and tumour development.&lt;p&gt;&lt;/p&gt; Results: LIMK2 expression was reduced in intestinal tumours of cancer-prone mice, as well as in human CRC cell lines and tumours. Reduced LIMK2 expression and substrate phosphorylation were associated with shorter patient survival. Genetic analysis in Drosophila midgut and intestinal epithelial cells isolated from genetically modified mice revealed a conserved role for LIMK2 in constraining gastrointestinal stem cell proliferation. Limk2 deletion increased colon tumour size in a colitis-associated colorectal mouse cancer model.&lt;p&gt;&lt;/p&gt; Conclusions: This study revealed that LIMK2 expression and activity progressively decrease with advancing stage, and supports the hypothesis that there is selective pressure for reduced LIMK2 expression in CRC to relieve negative constraints imposed upon gastrointestinal stem cells.&lt;p&gt;&lt;/p&gt

From ‘rock stars’ to ‘hygiene factors’:teachers at private accountancy tuition providers

In this paper, we examine the role, status and autonomy of teachers at English private accountancy tuition providers from 1980 to the present. We argue that, during this period, teachers transformed from ‘rock stars’ who enjoyed significant status and autonomy over their work to ‘hygiene factors’ in a largely standardised and commodified teaching environment. Growing cost pressures on tuition providers and an increasing emphasis on the quality and consistency of the learning experience are identified as significant factors in this transformation. We discuss these findings with reference to current developments towards corporatisation and marketisation in the English higher education sector

Acupuncture for the Treatment of Dry Eye: A Multicenter Randomised Controlled Trial with Active Comparison Intervention (Artificial Teardrops)

To evaluate the effects of acupuncture compared to a control group using artificial tears.multicenter randomised controlled trial (three local research hospitals of South Korea).150 patients with moderate to severe dry eye.Participants were randomly allocated into four weeks of acupuncture treatment (bilateral BL2, GB14, TE 23, Ex1, ST1, GB20, LI4, LI11 and single GV23) or to the artificial tears group (sodium carboxymethylcellulose).The ocular surface disease index (OSDI), tear film break-up time (TFBUT), Schirmer Ι test, visual analogue scale (VAS) for self-assessment of ocular discomfort, general assessment (by both acupuncture practitioners and participants) and quality of life (QOL) through the Measure Yourself Medical Outcome Profile-2 (MYMOP-2).There was no statistically significant difference between two groups for the improvement of dry eye symptoms as measured by OSDI (MD -16.11, 95% CI [-20.91, -11.32] with acupuncture and -15.37, 95% CI [-19.57, -11.16] with artificial tears; P = 0.419), VAS (acupuncture: -23.84 [-29.59, -18.09]; artificial tears: -22.2 [-27.24, -17.16], P = 0.530) or quality of life (acupuncture: -1.32 [-1.65, -0.99]; artificial tears: -0.96 [-1.32, -0.6], P = 0.42) immediately after treatment. However, compared with artificial tears group, the OSDI (acupuncture: -16.15 [-21.38, -10.92]; artificial tears: -10.76 [-15.25, -6.27], P = 0.030) and VAS (acupuncture: -23.88 [-30.9, -16.86]; artificial tears: -14.71 [-20.86, -8.55], P = 0.018) were significantly improved in the acupuncture group at 8 weeks after the end of acupuncture treatment. TFBUT measurements increased significantly in the acupuncture group after treatment.Acupuncture may have benefits on the mid-term outcomes related to dry eye syndrome compared with artificial tears.ClinicalTrials.gov NCT01105221

The Effect of Tear Supplementation on Ocular Surface Sensations during the Interblink Interval in Patients with Dry Eye.

PURPOSE: To investigate the characteristics of ocular surface sensations and corneal sensitivity during the interblink interval before and after tear supplementation in dry eye patients. METHODS: Twenty subjects (41.88+/-14.37 years) with dry eye symptoms were included in the dry eye group. Fourteen subjects (39.13+/-11.27 years) without any clinical signs and/or symptoms of dry eye were included in the control group. Tear film dynamics was assessed by non-invasive tear film breakup time (NI-BUT) in parallel with continuous recordings of ocular sensations during forced blinking. Corneal sensitivity to selective stimulation of corneal mechano-, cold and chemical receptors was assessed using a gas esthesiometer. All the measurements were made before and 5 min after saline and hydroxypropyl-guar (HP-guar) drops. RESULTS: In dry eye patients the intensity of irritation increased rapidly after the last blink during forced blinking, while in controls there was no alteration in the intensity during the first 10 sec followed by an exponential increase. Irritation scores were significantly higher in dry eye patients throughout the entire interblink interval compared to controls (p0.05). CONCLUSION: Ocular surface irritation responses due to tear film drying are considerably increased in dry eye patients compared to normal subjects. Although tear supplementation improves the protective tear film layer, and thus reduce unpleasant sensory responses, the rapid rise in discomfort is still maintained and might be responsible for the remaining complaints of dry eye patients despite the treatment

Group A Streptococcus Secreted Esterase Hydrolyzes Platelet-Activating Factor to Impede Neutrophil Recruitment and Facilitate Innate Immune Evasion

The innate immune system is the first line of host defense against invading organisms. Thus, pathogens have developed virulence mechanisms to evade the innate immune system. Here, we report a novel means for inhibition of neutrophil recruitment by Group A Streptococcus (GAS). Deletion of the secreted esterase gene (designated sse) in M1T1 GAS strains with (MGAS5005) and without (MGAS2221) a null covS mutation enhances neutrophil ingress to infection sites in the skin of mice. In trans expression of SsE in MGAS2221 reduces neutrophil recruitment and enhances skin invasion. The sse deletion mutant of MGAS5005 (ΔsseMGAS5005) is more efficiently cleared from skin than the parent strain. SsE hydrolyzes the sn-2 ester bond of platelet-activating factor (PAF), converting biologically active PAF into inactive lyso-PAF. KM and kcat of SsE for hydrolysis of 2-thio-PAF were similar to those of the human plasma PAF acetylhydrolase. Treatment of PAF with SsE abolishes the capacity of PAF to induce activation and chemotaxis of human neutrophils. More importantly, PAF receptor-deficient mice significantly reduce neutrophil infiltration to the site of ΔsseMGAS5005 infection. These findings identify the first secreted PAF acetylhydrolase of bacterial pathogens and support a novel GAS evasion mechanism that reduces phagocyte recruitment to sites of infection by inactivating PAF, providing a new paradigm for bacterial evasion of neutrophil responses