We set out to examine a postulated latitudinal trend in species richness within the Arctic Ocean. We compiled species records of tintinnid ciliates in the Arctic from the literature and added our own ...unpublished Chukchi Sea data to produce a database (available as an Online Resource data file) consisting of 1427 records of 89 species from 414 locations above 65°N sampled from 1885 to 2015. While there was no trend of species richness throughout the Arctic, there was a significant positive relationship between species richness and the number of sites sampled in a 2° band, suggesting a sampling effect. Plotting cumulative numbers of species and cumulative number of sites sampled by year, we found a linear relationship in log cumulative numbers of species and log sites sampled, and a lack of a plateau in the species accumulation trend. Species records are highly dominated by four species, accounting for 45% of the records:
Acanthostomella norvegica
,
Parafavella denticulata
,
Ptychocylis obtusa
and
Salpingella acuminata
, all of which, except
S. acuminata
, have long been suspected to be morphologically variable, with different morphotypes given undue species status. Pooling all reported species of
Acanthostomella
,
Parafavella
and
Ptychocylis
yielded little qualitative differences but considerable quantitative differences. We found large discrepancies in geographic coverage. We conclude that many zones projected to experience large changes in sea ice coverage are under-sampled. Based on the historical trend, the list of Arctic tintinnid ciliate species will likely continue to grow with new sampling, regardless of changes in the Arctic Seas.
Eleven patients being evaluated with intracranial electroencephalography for medically resistant temporal lobe epilepsy participated in a visual recognition memory task. Interictal epileptiform ...spikes were manually marked and their rate of occurrence compared between baseline and three 2 s periods spanning a 6 s viewing period. During successful, but not unsuccessful, encoding of the images there was a significant reduction in interictal epileptiform spike rate in the amygdala, hippocampus, and temporal cortex. During the earliest encoding period (0-2000 ms after image presentation) in these trials there was a widespread decrease in the power of theta, alpha and beta band local field potential oscillations that coincided with emergent focal gamma frequency activity. Interictal epileptiform spike rate correlated with spectral band power changes and broadband (4-150 Hz) desynchronization, which predicted significant reduction in interictal epileptiform spike rate. Spike-triggered averaging of the field potential power spectrum detected a burst of low frequency synchronization 200 ms before the interictal epileptiform spikes that arose during this period of encoding. We conclude that interictal epileptiform spikes are modulated by the patterns of network oscillatory activity that accompany human memory offering a new mechanistic insight into the interplay of cognitive processing, local field potential dynamics and interictal epileptiform spike generation.
OBJECTIVE:Angiopoietins are postulated diagnostic biomarkers in children and adults with severe sepsis and septic shock. The diagnostic value of angiopoietins in children less than 5 years old has ...not been established, nor has their effect on permeability in the capillary microvasculature. We aim to determine if levels of angiopoietin-1 or -2 (angpt-1, -2) are diagnostic for severe sepsis/shock in young children and whether they affect the permeability of cultured human dermal microvascular endothelial cells (HDMEC).
DESIGN:Prospective observational study of children < 5 years old. Patients were classified as non-systemic inflammatory response syndrome (SIRS), SIRS/sepsis and severe sepsis/septic shock.
SETTING:Tertiary care pediatric hospitals.
PATIENTS:Critically ill children.
INTERVENTIONS:None.
MEASUREMENTS:Plasma angpt-1 and -2 levels were measured with enzyme-linked immunoassays. Expression of angpt-2 in endothelial cells was assessed with quantitative polymerase chain reaction. Permeability changes in cultured HDMECs were assessed with transendothelial electrical resistance measurements.
RESULTS:Angpt-1 levels were significantly higher in younger children compared with levels found in previous study of older children across disease severity (all P < 0.001). Angpt-2 was significantly higher in this cohort with severe sepsis/septic shock compared with children without SIRS and SIRS/sepsis (all P < 0.003). Angpt-2/1 ratio was also elevated in children with severe sepsis/septic shock but an order of magnitude less than older children (P < 0.02, P = 0.002). Angpt-1 and -2 did not affect basal HDMEC permeability or modulate leak in isolation or in the presence of tumor necrosis factor (TNF).
CONCLUSIONS:Angpt-2 levels and the angpt-2/1 ratio are appropriate diagnostic biomarkers of severe sepsis/septic shock in children less than 5 years old. Neither angpt-1 nor -2 affects basal HDMEC permeability alone or modulates TNF induced capillary leak.
Shock refractory to fluid and catecholamine therapy has significant morbidity and mortality in children. The use of methylene blue to treat refractory shock in children is not well described. We aim ...to collect and summarize the literature and define physicians' practice patterns regarding the use of methylene blue to treat shock in children.
We conducted a systematic search of MEDLINE, Embase, PubMed, Web of Science, Cochrane for studies involving the use of methylene blue for catecholamine-refractory shock from database inception to 2019. Collected studies were analyzed qualitatively. To describe practice patterns of methylene blue use, we electronically distributed a survey to U.S.-based pediatric critical care physicians. We assessed physician knowledge and experience with methylene blue. Survey responses were quantitatively and qualitatively evaluated.
Pediatric critical and cardiac care units.
Patients less than or equal to 25 years old with refractory shock treated with methylene blue.
None.
One-thousand two-hundred ninety-three abstracts met search criteria, 139 articles underwent full-text review, and 24 studies were included. Studies investigated refractory shock induced by a variety of etiologies and found that methylene blue was generally safe and increased mean arterial blood pressure. There is overall lack of studies, low number of study patients, and low quality of studies identified. Our survey had a 22.5% response rate, representing 125 institutions. Similar proportions of physicians reported using (40%) or never even considering (43%) methylene blue for shock. The most common reasons for not using methylene blue were unfamiliarity with this drug, its proper dosing, and lack of evidentiary support.
Methylene blue appears safe and may benefit children with refractory shock. There is a stark divide in familiarity and practice patterns regarding its use among physicians. Studies to formally assess safety and efficacy of methylene blue in treating pediatric shock are warranted.
Despite the potential importance of black carbon (BC) for radiative forcing of the Arctic atmosphere, vertically resolved measurements of the particle light scattering coefficient (σsp) and light ...absorption coefficient (σap) in the springtime Arctic atmosphere are infrequent, especially measurements at latitudes at or above 80∘ N. Here, relationships among vertically distributed aerosol optical properties (σap, σsp and single scattering albedo or SSA), particle microphysics and particle chemistry are examined for a region of the Canadian archipelago between 79.9 and 83.4∘ N from near the surface to 500 hPa. Airborne data collected during April 2015 are combined with ground-based observations from the observatory at Alert, Nunavut and simulations from the Goddard Earth Observing System (GEOS) model, GEOS-Chem, coupled with the TwO-Moment Aerosol Sectional (TOMAS) model (collectively GEOS-Chem–TOMAS; Kodros et al., 2018) to further our knowledge of the effects of BC on light absorption in the Arctic troposphere. The results are constrained for σsp less than 15 Mm−1, which represent 98 % of the observed σsp, because the single scattering albedo (SSA) has a tendency to be lower at lower σsp, resulting in a larger relative contribution to Arctic warming. At 18.4 m2 g−1, the average BC mass absorption coefficient (MAC) from the combined airborne and Alert observations is substantially higher than the two averaged modelled MAC values (13.6 and 9.1 m2 g−1) for two different internal mixing assumptions, the latter of which is based on previous observations. The higher observed MAC value may be explained by an underestimation of BC, the presence of small amounts of dust and/or possible differences in BC microphysics and morphologies between the observations and model. In comparing the observations and simulations, we present σap and SSA, as measured, and σap∕2 and the corresponding SSA to encompass the lower modelled MAC that is more consistent with accepted MAC values. Median values of the measured σap, rBC and the organic component of particles all increase by a factor of 1.8±0.1, going from near-surface to 750 hPa, and values higher than the surface persist to 600 hPa. Modelled BC, organics and σap agree with the near-surface measurements but do not reproduce the higher values observed between 900 and 600 hPa. The differences between modelled and observed optical properties follow the same trend as the differences between the modelled and observed concentrations of the carbonaceous components (black and organic). Model-observation discrepancies may be mostly due to the modelled ejection of biomass burning particles only into the boundary layer at the sources. For the assumption of the observed MAC value, the SSA range between 0.88 and 0.94, which is significantly lower than other recent estimates for the Arctic, in part reflecting the constraint of σsp<15 Mm−1. The large uncertainties in measuring optical properties and BC, and the large differences between measured and modelled values here and in the literature, argue for improved measurements of BC and light absorption by BC and more vertical profiles of aerosol chemistry, microphysics and other optical properties in the Arctic.
Ciliate microzooplankton are important grazers in most pelagic ecosystems and among them, tintinnids, with their largely species‐specific loricas, allow relatively easy assessment of questions of ...diversity and distributions. Herein, we present the results of a survey of species records of tintinnids from the Southern Ocean (locations below 40°S) reported in 56 publications yielding 2,047 species records (synonyms included) from 402 locations. The 192 species reported can be parsed into two main groups: 32 endemic Southern Ocean species, known only from 40°S and further south, and a second group of 181 widespread species, forms with extensive geographic ranges extending into the Southern Ocean. Widespread species reported from the Southern Ocean can be further divided into a group of 81 species, each recorded multiple times in the Southern Ocean waters and 70 apparent “stray” species which have only been found but once. The endemic and widespread species of the Southern Ocean show both distinct distributional patterns and morphological differences. The assemblage of Southern Ocean endemics is found mostly within the Antarctic zone delimited by the average location of the Polar Front and contains a relatively large portion of wide‐mouthed forms. We give suggestions for future study.
Vertical distributions of atmospheric dimethyl sulfide (DMS(g)) were sampled aboard the research aircraft Polar 6 near Lancaster Sound, Nunavut, Canada, in July 2014 and on pan-Arctic flights in ...April 2015 that started from Longyearbyen, Spitzbergen, and passed through Alert and Eureka, Nunavut, and Inuvik, Northwest Territories. Larger mean DMS(g) mixing ratios were present during April 2015 (campaign mean of 116 ± 8 pptv) compared to July 2014 (campaign mean of 20 ± 6 pptv). During July 2014, the largest mixing ratios were found near the surface over the ice edge and open water. DMS(g) mixing ratios decreased with altitude up to about 3 km. During April 2015, profiles of DMS(g) were more uniform with height and some profiles showed an increase with altitude. DMS reached as high as 100 pptv near 2500 m. Relative to the observation averages, GEOS-Chem (www.geos-chem.org) chemical transport model simulations were higher during July and lower during April. Based on the simulations, more than 90 % of the July DMS(g) below 2 km and more than 90 % of the April DMS(g) originated from Arctic seawater (north of 66° N). During April, 60 % of the DMS(g), between 500 and 3000 m originated from Arctic seawater. During July 2014, FLEXPART (FLEXible PARTicle dispersion model) simulations locate the sampled air mass over Baffin Bay and the Canadian Arctic Archipelago 4 days back from the observations. During April 2015, the locations of the air masses 4 days back from sampling were varied: Baffin Bay/Canadian Archipelago, the Arctic Ocean, Greenland and the Pacific Ocean. Our results highlight the role of open water below the flight as the source of DMS(g) during July 2014 and the influence of long-range transport (LRT) of DMS(g) from further afield in the Arctic above 2500 m during April 2015.
: We aim to comprehensively describe the transcriptional activity and signaling of pulmonary parenchymal and immune cells before and after cardiopulmonary bypass (CPB) by using a multi-omic approach ...coupled with functional cellular assays. We hypothesize that key signaling pathways from specific cells within the lung alter pulmonary endothelial cell function resulting in worsening or improving disease.
: We collected serial tracheobronchial lavage samples from intubated patients less than 2-years-old undergoing surgery with CPB. Samples were immediately processed for single cell RNA sequencing (10x Genomics). Cell clustering, cell-type annotation, and visualization were performed, and differentially expressed genes (DEG) between serial samples were identified. Metabolomic and proteomic analyses were performed on the supernatant using mass spectrometry and a multiplex assay (SomaScan) respectively. Functional assays were done using electric cell-substrate impedance sensing to measure resistance across human pulmonary microvascular endothelial cells (HPMECs).
: Analysis of eight patients showed a heterogeneous mixture of pulmonary parenchymal and immune cells. Cell clustering demonstrated time-dependent changes in the transcriptomic signature indicating altered cellular phenotypes after CPB. DEG analysis was represented by genes involved in host defense, innate immunity, and the mitochondrial respiratory transport chain. Ingenuity pathway analysis showed upregulation of the integrated stress response across all cell types after CPB. Metabolomic analysis demonstrated upregulation of ascorbate and aldarate metabolism. Unbiased proteomic analysis revealed upregulation of proteins involved in cytokine and chemokine pathways. Post-CPB patient supernatant improved HMPEC barrier function, suggesting a protective cellular response to CPB.
: Children who undergo CPB for cardiac surgery have distinct cell populations, transcriptional activity, and metabolism that change over time. The response to ischemia-reperfusion injury in the lower airway of children appears to be protective, with the need to identify potential targets through future investigations.
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