Astrocytes possess an astounding degree of morphological complexity that enables them to interact with nearly every type of cell and structure within the brain. Through these interactions, astrocytes ...actively regulate many critical brain functions, including synapse formation, neurotransmission, and ion homeostasis. In the rodent brain, astrocytes grow in size and complexity during the first three postnatal weeks and establish distinct, non-overlapping territories to tile the brain. This protocol provides an established method for analyzing astrocyte territory volume and astrocyte tiling using free-floating tissue sections from the mouse brain. First, this protocol describes the steps for tissue collection, cryosectioning, and immunostaining of free-floating tissue sections. Second, this protocol describes image acquisition and analysis of astrocyte territory volume and territory overlap volume, using commercially available image analysis software. Lastly, this manuscript discusses the advantages, important considerations, common pitfalls, and limitations of these methods. This protocol requires brain tissue with sparse or mosaic fluorescent labeling of astrocytes, and is designed to be used with common lab equipment, confocal microscopy, and commercially available image analysis software.
The growth inhibitory nature of injured adult mammalian central nervous system (CNS) tissue constitutes a major barrier to robust axonal outgrowth and functional recovery following trauma or disease. ...Prototypic CNS regeneration inhibitors are broadly expressed in the healthy and injured brain and spinal cord and include myelin-associated glycoprotein (MAG), the reticulon family member NogoA, oligodendrocyte myelin glycoprotein (OMgp), and chondroitin sulfate proteoglycans (CSPGs). These structurally diverse molecules strongly inhibit neurite outgrowth in vitro, and have been most extensively studied in the context of nervous system injury in vivo. The physiological role of CNS regeneration inhibitors in the naïve, or uninjured, CNS remains less well understood, but has received growing attention in recent years and is the focus of this review. CNS regeneration inhibitors regulate myelin development and axon stability, consolidate neuronal structure shaped by experience, and limit activity-dependent modification of synaptic strength. Altered function of CNS regeneration inhibitors is associated with neuropsychiatric disorders, suggesting crucial roles in brain development and health.
Remyelination of CNS axons by Schwann cells (SCs) is not efficient, in part due to the poor migration of SCs into the adult CNS. Although it is known that migrating SCs avoid white matter tracts, the ...molecular mechanisms underlying this exclusion have never been elucidated. We now demonstrate that myelin-associated glycoprotein (MAG), a well known inhibitor of neurite outgrowth, inhibits rat SC migration and induces their death via γ-secretase-dependent regulated intramembrane proteolysis of the p75 neurotrophin receptor (also known as p75 cleavage). Blocking p75 cleavage using inhibitor X (Inh X), a compound that inhibits γ-secretase activity before exposing to MAG or CNS myelin improves SC migration and survival
Furthermore, mouse SCs pretreated with Inh X migrate extensively in the demyelinated mouse spinal cord and remyelinate axons. These results suggest a novel role for MAG/myelin in poor SC-myelin interaction and identify p75 cleavage as a mechanism that can be therapeutically targeted to enhance SC-mediated axon remyelination in the adult CNS.
Numerous studies have used Schwann cells, the myelin-making cells of the peripheral nervous system to remyelinate adult CNS axons. Indeed, these transplanted cells successfully remyelinate axons, but unfortunately they do not migrate far and so remyelinate only a few axons in the vicinity of the transplant site. It is believed that if Schwann cells could be induced to migrate further and survive better, they may represent a valid therapy for remyelination. We show that myelin-associated glycoprotein or CNS myelin, in general, inhibit rodent Schwann cell migration and induce their death via cleavage of the neurotrophin receptor p75. Blockade of p75 cleavage using a specific inhibitor significantly improves migration and survival of the transplanted Schwann cells
.
Innate immunity can facilitate nervous system regeneration, yet the underlying cellular and molecular mechanisms are not well understood. Here we show that intraocular injection of lipopolysaccharide ...(LPS), a bacterial cell wall component, or the fungal cell wall extract zymosan both lead to rapid and comparable intravitreal accumulation of blood-derived myeloid cells. However, when combined with retro-orbital optic nerve crush injury, lengthy growth of severed retinal ganglion cell (RGC) axons occurs only in zymosan-injected mice, and not in LPS-injected mice. In mice deficient for the pattern recognition receptor dectin-1but not Toll-like receptor-2 (TLR2), zymosan-mediated RGC regeneration is greatly reduced. The combined loss of dectin-1 and TLR2 completely blocks the proregenerative effects of zymosan. In the retina, dectin-1 is expressed by microglia and dendritic cells, but not by RGCs. Dectin-1 is also present on blood-derived myeloid cells that accumulate in the vitreous. Intraocular injection of the dectin-1 ligand curdlan a particulate form of ...(1, 3)-glucan promotes optic nerve regeneration comparable to zymosan in WT mice, but not in dectin-1-/- mice. Particulate ...(1, 3)-glucan leads to increased Erk1/2 MAP-kinase signaling and cAMP response element-binding protein (CREB) activation in myeloid cells in vivo. Loss of the dectin-1 downstream effector caspase recruitment domain 9 (CARD9) blocks CREB activation and attenuates the axon-regenerative effects of ...(1, 3)-glucan. Studies with dectin-1-/-/WT reciprocal bone marrow chimeric mice revealed a requirement for dectin-1 in both retina-resident immune cells and bone marrow-derived cells for ...(1, 3)-glucan-elicited optic nerve regeneration. Collectively, these studies identify a molecular framework of how innate immunity enables repair of injured central nervous system neurons. (ProQuest: ... denotes formulae/symbols omitted.)
BACKGROUND: The Anti-Inflammatory Diet (IBD-AID) is a nutritional regimen for inflammatory bowel disease (IBD) that restricts the intake of certain carbohydrates, includes the ingestion of pre- and ...probiotic foods, and modifies dietary fatty acids to demonstrate the potential of an adjunct dietary therapy for the treatment of IBD. METHODS: Forty patients with IBD were consecutively offered the IBD-AID to help treat their disease, and were retrospectively reviewed. Medical records of 11 of those patients underwent further review to determine changes in the Harvey Bradshaw Index (HBI) or Modified Truelove and Witts Severity Index (MTLWSI), before and after the diet. RESULTS: Of the 40 patients with IBD, 13 patients chose not to attempt the diet (33%). Twenty-four patients had either a good or very good response after reaching compliance (60%), and 3 patients’ results were mixed (7%). Of those 11 adult patients who underwent further medical record review, 8 with CD, and 3 with UC, the age range was 19–70 years, and they followed the diet for 4 or more weeks. After following the IBD-AID, all (100%) patients were able to discontinue at least one of their prior IBD medications, and all patients had symptom reduction including bowel frequency. The mean baseline HBI was 11 (range 1–20), and the mean follow-up score was 1.5 (range 0–3). The mean baseline MTLWSI was 7 (range 6–8), and the mean follow-up score was 0. The average decrease in the HBI was 9.5 and the average decrease in the MTLWSI was 7. CONCLUSION: This case series indicates potential for the IBD-AID as an adjunct dietary therapy for the treatment of IBD. A randomized clinical trial is warranted.
Objective: Because of the high rates of sexual assault on college campuses, it is important to examine factors that influence perceptions of healthy relationships and consent, including social media. ...Because college students are heavy users of social media, it is imperative to consider how social media can influence their participation in risky behavior, including the attitudes and norms around sex and relationships. Participants: Undergraduate college students were recruited to participate in a study that sought to understand how college students navigate romantic and sexual relationships. Methods: Participants (N = 392) completed a survey that assessed social media use, and how they perceived healthy relationship behavior and consent. Results: Results showed social media had more of an influence on perceptions of healthy relationships. However, the influence of social media on consent and healthy relationships is inconsistent across platforms; emphasizing the need for further research.
During gravitropism, the potential energy of gravity is converted into a biochemical signal. How this transfer occurs remains one of the most exciting mysteries in plant cell biology. New experiments ...are filling in pieces of the puzzle. In this review, we introduce gravitropism and give an overview of what we know about gravity sensing in roots of vascular plants, with special highlight on recent papers. When plant roots are reoriented sideways, amyloplast resedimentation in the columella cells is a key initial step in gravity sensing. This process somehow leads to cytoplasmic alkalinization of these cells followed by relocalization of auxin efflux carriers (PINs). This changes auxin flow throughout the root, generating a lateral gradient of auxin across the cap that upon transmission to the elongation zone leads to differential cell elongation and gravibending. We will present the evidence for and against the following players having a role in transferring the signal from the amyloplast sedimentation into the auxin signaling cascade: mechanosensitive ion channels, actin, calcium ions, inositol trisphosphate, receptors/ligands, ARG1/ARL2, spermine, and the TOC complex. We also outline auxin transport and signaling during gravitropism.
To characterize patients with coronavirus disease 2019 (covid-19) in a large New York City medical center and describe their clinical course across the emergency department, hospital wards, and ...intensive care units.
Retrospective manual medical record review.
NewYork-Presbyterian/Columbia University Irving Medical Center, a quaternary care academic medical center in New York City.
The first 1000 consecutive patients with a positive result on the reverse transcriptase polymerase chain reaction assay for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) who presented to the emergency department or were admitted to hospital between 1 March and 5 April 2020. Patient data were manually abstracted from electronic medical records.
Characterization of patients, including demographics, presenting symptoms, comorbidities on presentation, hospital course, time to intubation, complications, mortality, and disposition.
Of the first 1000 patients, 150 presented to the emergency department, 614 were admitted to hospital (not intensive care units), and 236 were admitted or transferred to intensive care units. The most common presenting symptoms were cough (732/1000), fever (728/1000), and dyspnea (631/1000). Patients in hospital, particularly those treated in intensive care units, often had baseline comorbidities including hypertension, diabetes, and obesity. Patients admitted to intensive care units were older, predominantly male (158/236, 66.9%), and had long lengths of stay (median 23 days, interquartile range 12-32 days); 78.0% (184/236) developed acute kidney injury and 35.2% (83/236) needed dialysis. Only 4.4% (6/136) of patients who required mechanical ventilation were first intubated more than 14 days after symptom onset. Time to intubation from symptom onset had a bimodal distribution, with modes at three to four days, and at nine days. As of 30 April, 90 patients remained in hospital and 211 had died in hospital.
Patients admitted to hospital with covid-19 at this medical center faced major morbidity and mortality, with high rates of acute kidney injury and inpatient dialysis, prolonged intubations, and a bimodal distribution of time to intubation from symptom onset.
The incidence of extreme natural hazard events in the U.S. has been rising, with far‐reaching implications for the U.S. agricultural sector. Yet, government expenditures on natural hazards in ...agriculture remain largely concentrated on recovery programs that compensate producers for damages after the fact. This article presents a risk management approach that incorporates a focus on prevention and mitigation which could offer greater cost‐effectiveness and help to build a more resilient agricultural sector. In this context, we explore the U.S. agricultural risk management policy landscape and identify some possibilities for how such an approach could be integrated into current programming.
Seedlings of two species of mangroves,
Bruguiera gymnorrhiza
and
Rhizophora apiculata
, were monitored for 8 years on the Pacific island of Kosrae, Federated States of Micronesia, to determine the ...effects of canopy cover and hydrogeomorphic zone on long-term survival and growth. Annual rainfall is high with little seasonality. Study plots with seedling subplots were in fringe, riverine, and interior hydrogeomorphic zones along four small rivers. The height of each seedling was measured each year and was designated each time as being under an open, partially closed, or closed canopy. Growth rates of both species were slow, and no seedling that was newly established during the study became a sapling (2 m). Many seedlings stopped growing for long periods of time.
Bruguiera
seedlings were more numerous than
Rhizophora
seedlings. They grew faster than
Rhizophora
seedlings except in riverine zones. Predicted growth rates of
Bruguiera
were fastest under an open canopy and slowest under a closed canopy, but
Rhizophora
was not affected by canopy status. Overall mortality rates for the two species were similar, averaging 36% year
−1
. El-Niño-Southern Oscillation events did not affect growth or mortality but may have caused some defoliation.
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