Two-dimensional gravitactic bioconvection in a protozoan (tetrahymena pyriformis) culture

Gravitactic bioconvective patterns created by Tetrahymena pyriformis in a Hele-Shaw apparatus were realized and compared with theoretical results. There were found to be two thresholds for bioconvection development: the first indicates the transition from the diffusion to the steady convection state; the second corresponds to the transition from the steady to the unsteady convection state. The results showed that the Hele-Shaw apparatus may be used as a physical analogy of porous media to study 2D bioconvection, with possible extensions to larger scale biological systems where population growth and distribution are driven by similar bio-physical interactions.TNQ thanks Prof. N. Lima (Centre for Biological Engineering, University of Minho, Braga, Portugal) for his precious support and Prof. M. P. Sauvant Rochat (Cellular Biology Lab., Universite d'Auvergne, France) for her collaboration. We especially thank Mrs. Laviolette (Ecole Polytechnique de Montreal, Canada), and Mr. Morency and Mrs. Phoenix (University of Montreal, Canada), for their kind assistance. FG acknowledges support from the James S. McDonnell Foundation through a 21st Century Science Initiative award. We thank an anonymous reviewer for his interesting comments

Relationship between nitrate headache and outcome in patients with acute stroke: results from the efficacy of nitric oxide in stroke (ENOS) trial

IntroductionNitrate-induced headache is common and may signify responsive cerebral vasculature. We assessed the relationship between nitrate-headache and outcome in patients with acute stroke.Materials and MethodsPatients were those randomised to glyceryl trinitrate (GTN) versus no GTN in the Efficacy of Nitric Oxide in Stroke trial. Development of headache by end of treatment (day 7), and functional outcome (modified Rankin Scale, mRS, primary outcome) at day 90, were assessed. Analyses are adjusted for baseline prognostic factors and give odds ratio (OR) and mean difference (MD) with 95% confidence intervals (95% CI).ResultsIn 4011 patients, headache was more common in GTN than control (360, 18.0% vs. 170, 8.5%; 2

Effect of glyceryl trinitrate on haemodynamics in acute stroke: data from the Efficacy of Nitric Oxide in Stroke trial

Background and Purpose: Increased blood pressure (BP), heart rate and their derivatives (variability, pulse pressure, rate-pressure product [RPP]) are associated with poor clinical outcome in acute stroke. We assessed the effects of glyceryl trinitrate (GTN) on haemodynamic parameters, and these on outcome in participants in the Efficacy of Nitric Oxide in Stroke trial.Methods: 4011 patients with acute stroke and raised BP were randomised within 48 hours of onset to transdermal GTN or no GTN for 7 days. Peripheral haemodynamics were measured at baseline (3 measures) and daily (2 measures) during treatment. Between-visit BP variability over days 1 to 7 (as standard deviation) was assessed in quintiles. Functional outcome was assessed as modified Rankin Scale (mRS) and cognition as telephone mini-mental state examination (t-MMSE) at day 90. Analyses were adjusted for baseline prognostic variables. Data are mean difference (MD) or odds ratios (OR) with 95% confidence intervals (CI).Results: Increased baseline BP (diastolic, variability), heart rate and RPP were each associated with unfavourable functional outcome at day 90. Increased between-visit systolic BP variability was associated with an unfavourable shift in mRS (highest quintile adjusted OR 1.65, 95% CI 1.37 to 1.99), worse cognitive scores (t-MMSE: highest quintile adjusted MD -2.03, 95% CI -2.84 to -1.22) and increased odds of death at day 90 (highest quintile adjusted OR 1.57, 95% CI 1.12 to 2.19). GTN lowered BP and RPP, and increased heart rate at day 1; and reduced between-visit systolic BP variability.Conclusions: Increased between-visit BP variability was associated with poor functional and cognitive outcomes and increased death 90 days after acute stroke. In addition to lowering BP and RPP, GTN reduced between-visit systolic BP variability. Agents that lower BP variability in acute stroke require further study

Continuing versus stopping prestroke antihypertensive therapy in acute intracerebral hemorrhage: a subgroup analysis of the efficacy of nitric oxide in stroke trial

Background and purpose: More than 50% of patients with acute intracerebral haemorrhage (ICH) are taking antihypertensive drugs before ictus. Although antihypertensive therapy should be given long term for secondary prevention, whether to continue or stop such treatment during the acute phase of ICH remains unclear, a question that was addressed in the Efficacy of Nitric Oxide in Stroke (ENOS) trial. Methods: ENOS was an international multicenter, prospective, randomized, blinded endpoint trial. Among 629 patients with ICH and systolic blood pressure between 140 and 220 mmHg, 246 patients who were taking antihypertensive drugs were assigned to continue (n = 119) or to stop (n = 127) taking drugs temporarily for 7 days. The primary outcome was the modified Rankin Score at 90 days. Secondary outcomes included death, length of stay in hospital, discharge destination, activities of daily living, mood, cognition, and quality of life. Results: Blood pressure level (baseline 171/92 mmHg) fell in both groups but was significantly lower at 7 days in those patients assigned to continue antihypertensive drugs (difference 9.4/3.5 mmHg, P < .01). At 90 days, the primary outcome did not differ between the groups; the adjusted common odds ratio (OR) for worse outcome with continue versus stop drugs was .92 (95% confidence interval, .45- 1.89; P = .83). There was no difference between the treatment groups for any secondary outcome measure, or rates of death or serious adverse events. Conclusions: Among patients with acute ICH, immediate continuation of antihypertensive drugs during the first week did not reduce death or major disability in comparison to stopping treatment temporarily

Route of feeding as a proxy for dysphagia after stroke and the effect of transdermal glyceryl trinitrate: data from the efficacy of nitric oxide in stroke randomised controlled trial

Post-stroke dysphagia is common, associated with poor outcome and often requires non-oral feeding/fluids. The relationship between route of feeding and outcome, as well as treatment with glyceryl trinitrate (GTN), was studied prospectively. The Efficacy of Nitric Oxide in Stroke (ENOS) trial assessed transdermal GTN (5 mg versus none for 7 days) in 4011 patients with acute stroke and high blood pressure. Feeding route (oral = normal or soft diet; nonoral = nasogastric tube, percutaneous endoscopic gastrostomy tube, parenteral fluids, no fluids) was assessed at baseline and day 7. The primary outcome was the modified Rankin Scale (mRS) measured at day 90. At baseline, 1331 (33.2%) patients had non-oral feeding, were older, had more severe stroke and more were female, than 2680 (66.8%) patients with oral feeding. By day 7, 756 patients had improved from non-oral to oral feeding, and 119 had deteriorated. Non-oral feeding at baseline was associated with more impairment at day 7 (Scandinavian Stroke Scale 29.0 versus 43.7; 2p < 0.001), and worse mRS (4.0 versus 2.7; 2p < 0.001) and death (23.6 versus 6.8%; 2p = 0.014) at day 90. Although GTN did not modify route of feeding overall, randomisation ≤6 hours of stroke was associated with a move to more oral feeding at day 7 (odds ratio = 0.61, 95% confidence intervals 0.38, 0.98; 2p = 0.040). As a proxy for dysphagia, non-oral feeding is present in 33% of patients with acute stroke and associated with more impairment, dependency and death. GTN moved feeding route towards oral intake if given very early after stroke

It is safe to use transdermal glyceryl trinitrate to lower blood pressure in patients with acute ischaemic stroke with carotid stenosis

Background There is concern that blood pressure (BP) lowering in acute stroke may compromise cerebral perfusion and worsen outcome in the presence of carotid stenosis. We assessed the effect of glyceryl trinitrate (GTN) in patients with carotid stenosis using data from the Efficacy of Nitric Oxide in Stroke (ENOS) Trial.Methods ENOS randomised 4011 patients with acute stroke and raised systolic BP (140–220 mm Hg) to transdermal GTN or no GTN within 48 hours of onset. Those on prestroke antihypertensives were also randomised to stop or continue their medication for 7 days. The primary outcome was the modified Rankin Scale (mRS) at day 90. Ipsilateral carotid stenosis was split

Plasmid pP62BP1 isolated from an Arctic Psychrobacter sp. strain carries two highly homologous type II restriction-modification systems and a putative organic sulfate metabolism operon

The complete nucleotide sequence of plasmid pP62BP1 (34,467 bp), isolated from Arctic Psychrobacter sp. DAB_AL62B, was determined and annotated. The conserved plasmid backbone is composed of several genetic modules, including a replication system (REP) with similarities to the REP region of the iteron-containing plasmid pPS10 of Pseudomonas syringae. The additional genetic load of pP62BP1 includes two highly related type II restriction-modification systems and a set of genes (slfRCHSL) encoding enzymes engaged in the metabolism of organic sulfates, plus a putative transcriptional regulator (SlfR) of the AraC family. The pP62BP1 slflocus has a compact and unique structure. It is predicted that the enzymes SlfC, SlfH, SlfS and SlfL carry out a chain of reactions leading to the transformation of alkyl sulfates into acyl-CoA, with dodecyl sulfate (SDS) as a possible starting substrate. Comparative analysis of the nucleotide sequences of pP62BP1 and other Psychrobacter spp. plasmids revealed their structural diversity. However, the presence of a few highly conserved DNA segments in pP62BP1, plasmid 1 of P. cryohalolentis K5 and pRWF-101 of Psychrobacter sp. PRwf-1 is indicative of recombinational shuffling of genetic information, and is evidence of lateral gene transfer in the Arctic environment

Baseline characteristics of the 4011 patients recruited into the 'Efficacy of Nitric Oxide in Stroke' (ENOS) trial

BACKGROUND: High blood pressure is common in acute stroke and associated with a worse functional outcome. Many patients who present with acute stroke are taking prescribed antihypertensive therapy before their stroke. AIMS: ENOS tested whether lowering blood pressure and continuing pre-stroke antihypertensive therapy are each safe and effective. METHODS: This study is an international multi-centre prospective randomized single-blind blinded-endpoint parallel-group partial-factorial controlled trial of transdermal glyceryl trinitrate(a nitric oxide donor, given for seven-days) vs. no glyceryl trinitrate, and of continuing vs. stopping (temporarily for seven-days) pre-stroke antihypertensive drugs if relevant, inpatients with acute ischaemic stroke or intracerebral haemorrhage and high systolic blood pressure (140–220 mmHg). RESULTS: Recruitment ran from July 2001 to October 2013. Four thousand eleven patients [2097 (52·3%) in the continue/stop arm] were recruited from 173 sites across 23 countries in 5 continents (Asia 14%, Continental Europe 16%, UK 64%). Baseline characteristics include: mean age 70 (standard deviation 12) years; male 57%; mean time from stroke to recruitment 26 (13) h; mean severity (Scandinavian Stroke Scale) 34(13) of 58; mean blood pressure 167 (19)/90 (13) mmHg; ischaemic stroke 83%; and intracerebral haemorrhage 16%. The main trial results will be presented in May 2014. The results will also be presented in updated Cochrane systematic reviews and included in individual patient data meta-analyses of all relevant randomized controlled trials. CONCLUSION: ENOS is a large completed international trial of blood pressure management in acute stroke and includes patients representative of many stroke services worldwide

Rates, distribution and implications of postzygotic mosaic mutations in autism spectrum disorder

We systematically analyzed postzygotic mutations (PZMs) in whole-exome sequences from the largest collection of trios (5,947) with autism spectrum disorder (ASD) available, including 282 unpublished trios, and performed resequencing using multiple independent technologies. We identified 7.5% of de novo mutations as PZMs, 83.3% of which were not described in previous studies. Damaging, nonsynonymous PZMs within critical exons of prenatally expressed genes were more common in ASD probands than controls (P < 1 Ã 10-6), and genes carrying these PZMs were enriched for expression in the amygdala (P = 5.4 Ã 10-3). Two genes (KLF16 and MSANTD2) were significantly enriched for PZMs genome-wide, and other PZMs involved genes (SCN2A, HNRNPU and SMARCA4) whose mutation is known to cause ASD or other neurodevelopmental disorders. PZMs constitute a significant proportion of de novo mutations and contribute importantly to ASD risk