Evidence for the lineage relationship between embryonic and adult hematopoietic stem cells (HSCs) in the mouse is primarily indirect. In order to study this relationship in a direct manner, we ...expressed the tamoxifen-inducible Cre-ERT recombinase under the control of the stem cell leukemia (Scl) stem-cell enhancer in transgenic mice (HSC-SCL-Cre-ERT). To determine functionality, HSC-SCL-Cre-ERT transgenics were bred with Cre reporter mice. Flow cytometric and transplantation studies revealed tamoxifen-dependent recombination occurring in more than 90% of adult long-term HSCs, whereas the targeted proportion within mature progenitor populations was significantly lower. Moreover, the transgene was able to irreversibly tag embryonic HSCs on days 10 and 11 of gestation. These cells contributed to bone marrow hematopoiesis 5 months later. In order to investigate whether the de novo HSC generation is completed during embryogenesis, HSC-SCL-Cre-ERT–marked fetal liver cells were transplanted into adult recipients. Strikingly, the proportion of marked cells within the transplanted and the in vivo–remaining HSC compartment was not different, implying that no further HSC generation occurred during late fetal and neonatal stages of development. These data demonstrate for the first time the direct lineage relationship between midgestation embryonic and adult HSCs in the mouse. Additionally, the HSC-SCL-Cre-ERT mice will provide a valuable tool to achieve temporally controlled genetic manipulation of HSCs.
To compare NREM EEG power in primary insomnia (PI) and good sleeper controls (GSC), examining both sex and NREM period effects; to examine relationships between EEG power, clinical characteristics, ...and self-reports of sleep.
Overnight polysomnographic study.
Sleep laboratory.
PI (n=48; 29 women) and GSC (n=25; 15 women).
None.
EEG power from 1-50 Hz was computed for artifact-free sleep epochs across four NREM periods. Repeated measures mixed effect models contrasted differences between groups, EEG frequency bands, and NREM periods. EEG power-frequency curves were modeled using regressions with fixed knot splines.
Mixed models showed no significant group (PI vs. GSC) differences; marginal sex differences (delta and theta bands); significant differences across NREM periods; and group*sex and group*NREM period interactions, particularly in beta and gamma bands. Modeled power-frequency curves showed no group difference in whole-night NREM, but PI had higher power than GSC from 18-40 Hz in the first NREM period. Among women, PI had higher 16 to 44-Hz power than GSC in the first 3 NREM periods, and higher 3 to 5-Hz power across all NREM periods. PI and GSC men showed no consistent differences in EEG power. High-frequency EEG power was not related to clinical or subjective sleep ratings in PI.
Women with PI, but not men, showed increased high-frequency and low-frequency EEG activity during NREM sleep compared to GSC, particularly in early NREM periods. Sex and NREM period may moderate quantitative EEG differences between PI and GSC.
corrected It has recently been suggested that the poly(butylcyanoacrylate) (PBCA) nanoparticle drug delivery system has a generalized toxic effect on the blood-brain barrier (BBB) (8) and that this ...effect forms the basis of an apparent enhanced drug delivery to the brain. The purpose of this study is to explore more fully the mechanism by which PBCA nanoparticles can deliver drugs to the brain.
Both in vivo and in vitro methods have been applied to examine the possible toxic effects of PBCA nanoparticles and polysorbate-80 on cerebral endothelial cells. Human, bovine, and rat models have been used in this study.
In bovine primary cerebral endothelial cells, nontoxic levels of PBCA particles and polysorbate-80 did not increase paracellular transport of sucrose and inulin in the monolayers. Electron microscopic studies confirm cell viability. In vivo studies using the antinociceptive opioid peptide dalargin showed that both empty PBCA nanoparticles and polysorbate-80 did not allow dalargin to enter the brain in quantities sufficient to cause antinociception. Only dalargin preadsorbed to PBCA nanoparticles was able to induce an antinociceptive effect in the animals.
At concentrations of PBCA nanoparticles and polysorbate-80 that achieve significant drug delivery to the brain, there is little in vivo or in vitro evidence to suggest that a generalized toxic effect on the BBB is the primary mechanism for drug delivery to the brain. The fact that dalargin has to be preadsorbed onto nanoparticles before it is effective in inducing antinociception suggests specific mechanisms of delivery to the CNS rather than a simple disruption of the BBB allowing a diffusional drug entry.
Little is known about the origin of the neuroactive steroids dehydroepiandrosterone sulphate (DHEAS) and pregnenolone sulphate (PregS) in the brain or of their subsequent metabolism. Using rat brain ...perfusion in situ, we have found 3H‐PregS to enter more rapidly than 3H‐DHEAS and both to undergo extensive (> 50%) desulphation within 0.5 min of uptake. Enzyme activity for the steroid sulphatase catalysing this deconjugation was enriched in the capillary fraction of the blood–brain barrier and its mRNA expressed in cultures of rat brain endothelial cells and astrocytes. Although permeability measurements suggested a net efflux, addition of the efflux inhibitors GF120918 and/or MK571 to the perfusate reduced rather than enhanced the uptake of 3H‐DHEAS and 3H‐PregS; a further reduction was seen upon the addition of unlabelled steroid sulphate, suggesting a saturable uptake transporter. Analysis of brain fractions after 0.5 min perfusion with the 3H‐steroid sulphates showed no further metabolism of PregS beyond the liberation of free steroid pregnenolone. By contrast, DHEAS underwent 17‐hydroxylation to form androstenediol in both the steroid sulphate and the free steroid fractions, with some additional formation of androstenedione in the latter. Our results indicate a gain of free steroid from circulating steroid sulphates as hormone precursors at the blood–brain barrier, with implications for ageing, neurogenesis, neuronal survival, learning and memory.
Despite designation as a neurosteroid, the origins of dehydroepiandrosterone (DHEA) and its sulphate ester (DHEAS) in adult brain are obscure. We show uptake of DHEAS at the rat blood–brain barrier and desulphation within 0.5 min to yield DHEA into the brain parenchyma. Further metabolism of DHEA(S) to androstenediol(S) suggested blood DHEAS as a precursor of brain androgenic and/or estrogenic hormones. Pregnenolone sulphate was also taken up and desulphated at the blood‐brain barrier, but did not undergo such rapid further metabolism.
Effective leadership is crucial to team performance within the intensive care unit. This novel study aimed to explore how staff members from an intensive care unit conceptualize leadership and what ...facilitators and barriers to leadership exist within a simulated workplace. It also aimed to identify factors that intersect with their perceptions of leadership. This study was underpinned by interpretivism, and video-reflexive ethnography was chosen as the methodology for the study. The use of both video recording (to capture the complex interactions occurring in the ICU) and team reflexivity allowed repeated analysis of those interactions by the research team. Purposive sampling was used to recruit participants from an ICU in a large tertiary and private hospital in Australia. Simulation groups were designed to replicate the typical clinical teams involved in airway management within the intensive care unit. Twenty staff participated in the four simulation activities (five staff per simulation group). Each group simulated the intubations of three patients with hypoxia and respiratory distress due to severe COVID-19. All 20 participants who completed the study simulations were invited to attend video-reflexivity sessions with their respective group. Twelve of the 20 participants (60%) from the simulations took part in the reflexive sessions. Video-reflexivity sessions (142 min) were transcribed verbatim. Transcripts were then imported into NVivo software for analysis. The five stages of framework analysis were used to conduct thematic analysis of the video-reflexivity focus group sessions, including the development of a coding framework. All transcripts were coded in NVivo. NVivo queries were conducted to explore patterns in the coding. The following key themes regarding participants' conceptualizations of leadership within the intensive care were identified: (1) leadership is both a group/shared process and individualistic/hierarchical; (2) leadership is communication; and (3) gender is a key leadership dimension. Key facilitators identified were: (1) role allocation; (2) trust, respect and staff familiarity; and (3) the use of checklists. Key barriers identified were: (1) noise and (2) personal protective equipment. The impact of socio-materiality on leadership within the intensive care unit is also identified.
It was recently shown that doxorubicin (DOX) bound to polysorbate-coated nanoparticles (NP) crossed the intact blood-brain barrier (BBB), and thus reached therapeutic concentrations in the brain. ...Here, we investigated the biodistribution in the brain and in the body of poly(butyl-2-cyano3-14Cacrylate) NP (14C-PBCA NP), polysorbate 80 (PS 80)-coated 14C-PBCA NP, DOX-loaded 14C-PBCA NP in glioblastoma 101/8-bearing rats after i.v. injection. The biodistribution profiles and brain concentrations of radiolabeled NP were determined by radioactivity counting after i.v. administration in rats. Changes in BBB permeability after tumour inoculation were assessed by i.v. injection of Evans Blue solution. The accumulation of NP in the tumour site and in the contralateral hemisphere in glioblastoma bearing-rats probably was augmented by the enhanced permeability and retention effect (EPR effect) that may have been becoming instrumental due to the impaired BBB on the NP delivery into the brain.
The uptake of the NP by the organs of the reticuloendothelial system (RES) was reduced after PS 80-coating, but the addition of DOX increased again the concentration of NP in the RES.
The common reactions of dioxygen, superoxide, and hydroperoxides with thiolates are thought to proceed via persulfenate intermediates, yet these have never been visualized. Here we report a 1.4 Å ...resolution crystal structure of the Fe2+-dependent enzyme cysteine dioxygenase (CDO) containing this putative intermediate trapped in its active site pocket. The complex raises the possibility that, distinct from known dioxygenases and proposed CDO mechanisms, the Fe-proximal oxygen atom may be involved in the primary oxidation event yielding a unique three-membered Fe−S−O cyclic intermediate. A nonpolar environment of the distal oxygen would facilitate isomerization of the persulfenate to the sulfinate product.
Water‐group gas continuously escapes from Jupiter's icy moons to form co‐orbiting populations of particles or neutral toroidal clouds. These clouds provide insights into their source moons as they ...reveal loss processes and compositions of their parent bodies, alter local plasma composition, and act as sources and sinks for magnetospheric particles. We report the first observations of H2+ pickup ions in Jupiter's magnetosphere from 13 to 18 Jovian radii and find a density ratio of H2+/H+ = 8 ± 4%, confirming the presence of a neutral H2 toroidal cloud. Pickup ion densities monotonically decrease radially beyond 13 RJ consistent with an advecting Europa‐genic toroidal cloud source. From these observations, we derive a total H2 neutral loss rate from Europa of 1.2 ± 0.7 kg s−1. This provides the most direct estimate of Europa's H2 neutral loss rate to date and underscores the importance of both ion composition and neutral toroidal clouds in understanding satellite‐magnetosphere interactions.
Plain Language Summary
Jupiter's moons Europa, Ganymede, and Callisto all have icy surfaces which interact with their local environments. From this interaction, water‐group atoms and molecules are released from the icy surfaces and orbit Jupiter as a collection of material in “neutral toroidal clouds.” The material in these toroidal clouds interact with the local charged particle environment, where neutrals in the toroidal clouds can become charged and incorporated into Jupiter's charged particle environment. Here, we highlight observations of Jupiter's charged particle environment and present the first detections of H2+ in this environment. These H2+ ions are shown to be originally produced from H2 lost from Europa and the abundance of detected ions allows us to determine Europa is losing 1.2 ± 0.7 kg s−1 of neutral H2. This provides the most direct estimate of Europa's H2 neutral loss rate to date and underscores the importance of both ion composition and neutral toroidal clouds in understanding how satellites interact with their local charged particle environments.
Key Points
First identification of H2+ in the Jovian magnetosphere from 13 to 18 RJ, with a density ratio of H2+/H+ = 8 ± 4%
H2+ in Jupiter's magnetosphere is predominantly produced by Europa's neutral toroidal cloud
Europa's total H2 neutral loss rate is 1.2 ± 0.7 kg s−1
Summary
Purpose: We undertook a systematic review of the evidence on disparities in epilepsy with a focus on North American data (Canada, United States, and the English‐speaking Caribbean).
Methods: ... We identified and evaluated: access to and outcomes following medical and surgical treatment, disability, incidence and prevalence, and knowledge and attitudes. An exhaustive search (1965–2007) was done, including: (1) disparities by socioeconomic status (SES), race/ethnicity, age, or education of subgroups of the epilepsy population; or (2) disparities between people with epilepsy (PWE) and healthy people or with other chronic illnesses.
Results: From 1,455 citations, 278 eligible s were identified and 44 articles were reviewed. Comparative research data were scarce in all areas. PWE have been shown to have lower education and employment status; among PWE, differences in access to surgery have been shown by racial/ethnic groups. Aboriginals, women, and children have been shown to differ in use of health resources. Poor compliance has been shown to be associated with lower SES, insufficient insurance, poor relationship with treating clinicians, and not having regular responsibilities.
Discussion: Comprehensive, comparative research on all aspects of disparities in epilepsy is needed to understand the causes of disparities and the development of any policies aimed at addressing health disparities and minimizing their impact.
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