The short-term benthic response to an input of fresh organic matter was examined in vastly contrasting benthic environments (estuarine intertidal to deep-sea) using 13C-labeled diatoms as a tracer of ...labile carbon. Benthic processing was assessed in major compartments through
13C-enrichment in σCO2, in bacteria-specific phospholipids and in fauna tissue. A rapid response was evident in all environments. Under warm bottom water (14-18°C), similar quantities of the added carbon were respired within 24 hours in shallow and deep-sea
sediments. However, the speed and magnitude of respiration were strongly reduced under low bottom water temperature (4-6°C), both in a shallow and a deep-sea site. Rapid carbon respiration even in deep-sea sediments almost devoid of fauna highlights the key role of bacteria, the
most ubiquitous benthic component, in this short-term respiration of fresh organic matter. However, when present, fauna rapidly ingest algal material, thereby increasing the amount of carbon processed and directly extending carbon flow pathways.
An onslaught of acerbic, confrontational wordplay, The Unabridged Devil's Dictionary offers some 1,600 wickedly clever definitions to the vocabulary of everyday life. Little is sacred and few are ...safe, for Bierce targets just about any pursuit, from matrimony to immortality, that allows our willful failings and excesses to shine forth.
Hypoxic ischemic brain injury secondary to pediatric cardiac arrest (CA) may result in acute symptomatic seizures. A high proportion of seizures may be nonconvulsive, so accurate diagnosis requires ...continuous EEG monitoring. We aimed to determine the safety and feasibility of long-term EEG monitoring, to describe electroencephalographic background and seizure characteristics, and to identify background features predictive of seizures in children undergoing therapeutic hypothermia (TH) after CA.
Nineteen children underwent TH after CA. Continuous EEG monitoring was performed during hypothermia (24 hours), rewarming (12-24 hours), and then an additional 24 hours of normothermia. The tolerability of these prolonged studies and the EEG background classification and seizure characteristics were described in a standardized manner.
No complications of EEG monitoring were reported or observed. Electrographic seizures occurred in 47% (9/19), and 32% (6/19) developed status epilepticus. Seizures were nonconvulsive in 67% (6/9) and electrographically generalized in 78% (7/9). Seizures commenced during the late hypothermic or rewarming periods (8/9). Factors predictive of electrographic seizures were burst suppression or excessively discontinuous EEG background patterns, interictal epileptiform discharges, or an absence of the expected pharmacologically induced beta activity. Background features evolved over time. Patients with slowing and attenuation tended to improve, whereas those with burst suppression tended to worsen.
EEG monitoring in children undergoing therapeutic hypothermia after cardiac arrest is safe and feasible. Electrographic seizures and status epilepticus are common in this setting but are often not detectable by clinical observation alone. The EEG background often evolves over time, with milder abnormalities improving and more severe abnormalities worsening.
A maximum-likelihood approach to multi-reference image refinement is presented. In contrast to conventional cross-correlation refinement, the new approach includes a formal description of the noise, ...implying that it is especially suited to cases with low signal-to-noise ratios. Application of this approach to a cryo-electron microscopy dataset revealed two major classes for projections of simian virus 40 large T-antigen in complex with an asymmetric DNA-probe, containing the origin of simian virus 40 replication. Strongly bent projections of dodecamers showed density that may be attributed to the complexed double-stranded DNA, while almost straight projections revealed a twist in the relative orientation of the hexameric subunits. This new level of detail for large T-antigen projections was not detected using conventional techniques. For a negative stain dataset, maximum-likelihood refinement yielded results that were practically identical to those obtained using conventional multi-reference refinement. Results obtained using simulated data suggest that the efficiency of the maximum-likelihood approach may be further enhanced by explicitly incorporating the microscope contrast transfer function in the image formation model.
To evaluate the effects of sleep on partial seizures arising from various brain regions.
The authors prospectively studied 133 patients with localization-related epilepsy undergoing video-EEG ...monitoring over a 2-year period. Seizure type, site of onset, sleep/wake state at onset, duration, and epilepsy syndrome diagnosis were recorded. Periorbital, chin EMG, and scalp/sphenoidal electrodes were used. A subset of 34 patients underwent all-night polysomnography with scoring of sleep stages.
The authors analyzed 613 seizures in 133 patients. Forty-three percent (264 of 613) of all partial seizures began during sleep. Sleep seizures began during stages 1 (23%) and 2 (68%) but were rare in slow-wave sleep; no seizures occurred during REM sleep. Temporal lobe complex partial seizures were more likely to secondarily generalize during sleep (31%) than during wakefulness (15%), but frontal lobe seizures were less likely to secondarily generalize during sleep (10% versus 26%; p < 0.005).
Partial-onset seizures occur frequently during NREM sleep, especially stage 2 sleep. Frontal lobe seizures are most likely to occur during sleep. Patients with temporal lobe seizures have intermediate sleep seizure rates, and patients with seizures arising from the occipital or parietal lobes have rare sleep-onset seizures. Sleep, particularly stage 2 sleep, promotes secondary generalization of temporal and occipitoparietal, but not frontal, seizures. These findings suggest that the hypersynchrony of sleep facilitates both initiation and propagation of partial seizures, and that effects of sleep depend in part on the location of the epileptic focus.
Hypertension Canada provides annually updated, evidence-based guidelines for the diagnosis, assessment, prevention, and treatment of hypertension in adults and children. This year, the adult and ...pediatric guidelines are combined in one document. The new 2018 pregnancy-specific hypertension guidelines are published separately. For 2018, 5 new guidelines are introduced, and 1 existing guideline on the blood pressure thresholds and targets in the setting of thrombolysis for acute ischemic stroke is revised. The use of validated wrist devices for the estimation of blood pressure in individuals with large arm circumference is now included. Guidance is provided for the follow-up measurements of blood pressure, with the use of standardized methods and electronic (oscillometric) upper arm devices in individuals with hypertension, and either ambulatory blood pressure monitoring or home blood pressure monitoring in individuals with white coat effect. We specify that all individuals with hypertension should have an assessment of global cardiovascular risk to promote health behaviours that lower blood pressure. Finally, an angiotensin receptor-neprilysin inhibitor combination should be used in place of either an angiotensin-converting enzyme inhibitor or angiotensin receptor blocker in individuals with heart failure (with ejection fraction < 40%) who are symptomatic despite appropriate doses of guideline-directed heart failure therapies. The specific evidence and rationale underlying each of these guidelines are discussed.
Chaque année Hypertension Canada publie une mise à jour de ses lignes directrices fondées sur des données probantes relatives au diagnostic, à l'évaluation, à la prévention et au traitement de l'hypertension chez l'adulte et l'enfant. Cette année, les lignes directrices applicables aux adultes et aux enfants sont combinées en un seul document. Les nouvelles lignes directrices 2018 portant précisément sur l'hypertension pendant la grossesse sont publiées séparément. Pour 2018, cinq nouvelles lignes directrices sont présentées, et une ligne directrice existante portant sur les seuils et les cibles de pression artérielle dans le contexte de la thrombolyse dans un cas d'accident vasculaire cérébral ischémique aigu est révisée. L'utilisation de tensiomètres-bracelets validés pour l'estimation de la pression artérielle chez les personnes dont le bras a une circonférence élevée est à présent incluse. Des indications sont données pour les mesures de la pression artérielle dans le cadre d'un suivi à l'aide de méthodes normalisées et de dispositifs électroniques (oscillométriques) positionnés au niveau du bras chez les personnes hypertendues, ainsi que de la surveillance de la pression artérielle ambulatoire ou à domicile chez les personnes sujettes au « syndrome de la blouse blanche ». Nous recommandons notamment de procéder à une évaluation du risque cardiovasculaire global de toutes les personnes atteintes d'hypertension afin de les inciter à adopter de saines habitudes de vie permettant d’abaisser leur pression artérielle. Enfin, chez les personnes atteintes d'insuffisance cardiaque (présentant une fraction d'éjection < 40 %) qui sont symptomatiques malgré un traitement de cette affection à des doses appropriées et conforme aux lignes directrices, il est recommandé d'utiliser une association de médicaments inhibiteurs des récepteurs de l'angiotensine et de la néprilysine au lieu d’un inhibiteur de l’enzyme de conversion de l'angiotensine ou d'un antagoniste des récepteurs de l'angiotensine en monothérapie. Les données probantes et la justification qui sous-tendent chacune de ces lignes directrices sont analysées.
Glutathione S-transferase alpha 4 (GSTA4) is a phase II detoxifying enzyme that metabolizes electrophiles and carcinogens including 4-hydroxy-2-nonenal (4-HNE), an endogenous carcinogen that ...contributes to colorectal carcinogenesis. In this study, we investigated GSTA4 expression and regulation in murine primary colonic epithelial cells, microbiome-driven murine colitis and human carcinomas. Exposure of YAMC cells to 4-HNE induced Gsta4 expression. Using an inflammation-associated model of colorectal cancer (CRC), Gsta4 expression increased in vivo in colon macrophages and serum after 2 weeks of colonization of IL-10 deficient (Il10
) mice with Enterococcus faecalis. Increased expression was noted after 9 months of colonization in colon macrophages and epithelia in areas of inflammation. In human colon biopsies, immunohistochemistry showed no GSTA4 expression in normal epithelial cells, whereas GSTA4 was strongly expressed in the neoplastic epithelia of invasive carcinomas. For tubular adenomas, increased expression was primarily noted in stromal macrophages. Increased GSTA4 was confirmed in established human CRC cell lines and associated with 4-HNE-protein adducts in human colon adenomas and CRC. Next, we showed that 4-HNE induced activation of c-Jun and Nrf2, two components of the oncogenic transcription factor AP-1. AP-1 inhibitors and gene-specific small interfering RNAs partially suppressed GSTA4 expression. Co-immunoprecipitation confirmed interactions between c-Jun and Nrf2 supporting a role for AP-1 in regulating 4-HNE-induced GSTA4 expression. These findings demonstrate GSTA4 activation during 4-HNE-induced neoplastic transformation in colorectal carcinogenesis. GSTA4 is a potential surrogate biomarker for CRC screening and should provide novel approaches for chemoprevention.
Optically stimulated luminescence (OSL) thermochronometry is an emerging application, whose capability to record sub-Million-year thermal histories is of increasing interest to a growing number of ...subdisciplines of Quaternary research. However, several recent studies have encountered difficulties both in extraction of OSL signals from bedrock quartz, and in their thermochronometric interpretation, thus highlighting the need for a methodological benchmark. Here, we investigate the characteristic OSL signals from quartz samples across all major types of bedrock and covering a wide range of chemical purities. High ratios of infrared to blue stimulated luminescence (IRSL/BLSL), an insensitive ‘fast’ OSL component, and anomalously short recombination lifetimes seen in time-resolved luminescence (TR-OSL), are often encountered in quartz from crystalline (magmatic and metamorphic) bedrock, and may hamper successful OSL dating. Furthermore, even when the desirable signal is present, its concentration might be indistinguishable from its environmental steady-state prediction, thus preventing its conversion to a cooling or heating history. We explore the saturation properties and the thermal activation parameters of various OSL signals in quartz to outline the capabilities and limitations for their use in low-temperature thermochronometry.
•We reinforce three quality control criteria for quartz OSL signals used in dating.•Bedrock quartz from low-grade metapelites often meets the proposed criteria.•Bedrock quartz from high-grade metamorphic and magmatic rocks generally does not.•Saturation of quartz OSL further narrows its thermochronological application.
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