39 research outputs found

    On nonhydrostatic coastal model simulations of shear instabilities in a stratified shear flow at high Reynolds number

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    Author Posting. © American Geophysical Union, 2017. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 122 (2017): 3081–3105, doi:10.1002/2016JC012334.The nonhydrostatic surface and terrain-following coastal model NHWAVE is utilized to simulate a continually forced stratified shear flow in a straight channel, which is a generic problem to test the existing nonhydrostatic coastal models' capability in resolving shear instabilities in the field scale. The resolved shear instabilities in the shear layer has a Reynolds number of about 1.4 × 106, which is comparable to field observed value. Using the standard Smagorinsky closure with a grid size close to the Ozmidov length scale, simulation results show that the resolved energy cascade exceeds 1 order of magnitude and the evolution and turbulent mixing characteristics are predicted well. Two different approaches are used to estimate the turbulent dissipation rate, namely using the resolved turbulent energy spectrum and the parameterized subgrid turbulent dissipation rate, and the predicted results provide the upper and lower bounds that encompass the measured values. Model results show significantly higher turbulence in braids of shear instabilities, which is similar to field observations while both the subgrid turbulent dissipation rate and resolved vorticity field can be used as surrogates for measured high acoustic backscatter signals. Simulation results also reveal that the surface velocity divergence/convergence is an effective identifier for the front of the density current and the shear instabilities. To guide future numerical studies in more realistic domains, an evaluation on the effects of different grid resolutions and subgrid viscosity on the resolved flow field and subgrid dissipation rate are discussed.Office of Naval Research Grant Numbers: N00014-15-1-2612 , N00014-16-1-2948; National Science Foundation Grant Numbers: OCE-1334325 , OCE-1232928; Extreme Science and Engineering Discovery Environment (XSEDE) SuperMIC Grant Number: TG-OCE1000152017-10-1

    A case report of anti-GAD65 antibody-positive autoimmune encephalitis in children associated with autoimmune polyendocrine syndrome type-II and literature review

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    BackgroundGlutamic acid decarboxylase (GAD) is the rate-limiting enzyme for the synthesis of gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the central nervous system. Antibodies against glutamic acid decarboxylase (GAD) are associated with various neurologic conditions described in patients, including stiff person syndrome, cerebellar ataxia, refractory epilepsy, and limbic and extra limbic encephalitis. While there are few case reports and research on anti-GAD65 antibody-associated encephalitis in adults, such cases are extremely rare in pediatric cases.MethodsFor the first time, we report a case of anti-GAD65-positive autoimmune encephalitis associated with autoimmune polyendocrine syndrome (APS) type II. We reviewed previously published pediatric cases of anti-GAD65 autoimmune encephalitis to discuss their clinical features, laboratory tests, imaging findings, EEG patterns, and prognosis.Case presentationAn 8-year-old, male child presented to the outpatient department after experiencing generalized convulsions for twenty days. The child was admitted for epilepsy and had received oral sodium valproate (500 mg/day) in another center, where investigations such as USG abdomen and MRI brain revealed no abnormalities, however, had abnormal EEG with diffuse mixed activity in the left anterior middle prefrontal temporal region. On the follow-up day, a repeat blood test showed a very low serum drug concentration of sodium valproate hence the dose was increased to 750 mg/day. Then, the child experienced adverse effects including increased sleep, thirst, and poor appetite, prompting the parents to discontinue the medication. A repeat MRI showed increased signals on FLAIR sequences in the right hippocampus hence admitted for further management. The child's past history included a diagnosis of hypothyroidism at the age of 4, and receiving levothyroxine 75 mcg once daily. His parents are healthy with no history of any similar neurological, autoimmune, or genetic diseases, but his uncle had a history of epilepsy. At presentation, he had uncontrolled blood glucose levels with elevated HbA1c levels. Additionally, the serum and CSF autoantibodies were positive against the anti-GAD65 antibody with the titer of 1:100 and 1:32 respectively. The patient was managed with a mixed type of insulin regimen and received first-line immunotherapy (intravenous immunoglobulin, IVIG) for five consecutive days, followed by oral prednisone and sodium valproate as an antiepileptic drug. Upon achieving a favorable clinical outcome, the patient was discharged with oral medications.ResultsAmong the 15 pediatric patients reported in this literature, nine presented with limbic encephalitis (LE), three with extralimbic encephalitis (ELE), and three with a combination of limbic and extralimbic encephalitis. Most of these cases exhibited T2-W FLAIR hyperintensities primarily localized to the temporal lobes in the early phase, progressing to hippocampal sclerosis/atrophy in the later phase on MRI. EEG commonly showed slow or spike waves on frontotemporal lobes with epileptic discharges. Prognostic factors varied among patients, with some experiencing persistent refractory seizures, type-1 diabetes mellitus (T1DM), persistent memory impairment, persistent disability requiring full assistance, and, in severe cases, death.ConclusionOur findings suggest that anti-GAD65 antibody-positive autoimmune encephalitis patients may concurrently present with other APS. Our unique case presented with multiple endocrine syndromes and represents the first reported occurrence in children. Early diagnosis and timely initiation of immunotherapy are crucial for improving clinical symptoms and reducing the likelihood of relapses or permanent disabilities. Therefore, emphasis should be placed on prompt diagnosis and appropriate treatment implementation to achieve better patient outcomes

    The global state of research in stem cells therapy for spinal cord injury (2003–2022): a visualized analysis

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    ObjectiveOur study aimed to visualize the global status and frontiers in stem cell therapy for spinal cord injury by using bibliometric methodology.MethodsPublication citation information related to stem cell therapy for spinal cord injury (SCI) studies between 2003 and 2022 was retrieved from the Web of Science Core Collection database. For the visualized study, VOS viewer software and Graph Pad Prism 9.5 were used to perform bibliometric analysis of included data and publication number statistics in stem cell therapy for the SCI domain.ResultsA total of 6,686 publications were retrieved. The USA and China made the highest contributions to global research with the highest number of citations and link strength. The journal Experimental Neurology ranks as the top journal, combining the publication amount and bibliometrics results. The University of Toronto, based in Canada, was the first-ranking institution. The directions of the current study could be divided into five clusters. The research of Transplantation and Regenerative Medicine and Neurosciences Mechanism Research may be the emerging frontiers in this domain.ConclusionIn summary, stem cell therapy for spinal cord injuries is poised for more valuable advances

    Glutaric Acid-Mediated Apoptosis in Primary Striatal Neurons

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    Glutaric acid (GA) has been implicated in the mechanism of neurodegeneration in glutaric aciduria type I. In the present study, the potential cytotoxic effects of GA (0.1~50 mM for 24~96 h) were examined in cultured primary rat striatal neurons. Results showed increase in the number of cells labeled by annexin-V or with apoptotic features shown by Hoechst/PI staining and transmission electron microscopy (TEM) and upregulation of the expression of mRNA as well as the active protein fragments caspase 3, suggesting involvement of the caspase 3-dependent apoptotic pathway in GA-induced striatal neuronal death. This effect was in part suppressed by the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 but not the α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) antagonist 6-cyano-7-nitroquinoxalone-2,3-dione (CNQX). Thus, GA may trigger neuronal damage partially through apoptotic pathway and via activation of NMDA receptors in cultured primary striatal neurons

    Akt pathway activation reduces platelet apoptosis and contributes to the increase of platelet counts in solid tumor patients

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    Platelets counts increase in various cancer patients, which is associated with poor prognosis. However, the cause of high platelet counts in cancer patients is still not fully understood. Here we demonstrated that compared with healthy controls, there were significant differences in platelet parameters, mean platelet volume (MPV), platelet distribution width (PDW), platelet larger cell ratio (P-LCR), and platelet crit (PCT), reflecting platelet volume in breast cancer patients by clinical retrospective analysis. The mitochondrial transmembrane potential (ΔΨm) depolarization and phosphatidylserine (PS) externalization declined, accompanied by reduced expression of pro-apoptotic factors Bak, Bax and apoptotic executor caspase-3, and elevated of anti-apoptotic factor Bcl-xl in various cancer patients’ platelets. Notably, the phosphorylation level of Akt and its downstream target Bad increased in platelets from cancer patients. MK2206, the inhibitor of Akt, reduced the phosphorylation level of Akt and Bad, and induced apoptosis of platelets. When platelets from healthy controls cocultured with the cultural supernatant of cancer cells, the phosphorylation level of Akt and Bad in the platelets was elevated and the cultural supernatant of cancer cells could rescue the apoptosis of platelet induced by MK2206. Therefore, in our study the apoptosis of platelets in cancer patients was declined, which exerted an influence on the rise of platelet counts in breast cancer patients. The cross-talking between tumor and platelets could affect platelet apoptosis by regulating Akt signaling pathway in platelets

    Efficacy of Immunization against a Novel Synthetic 13-Amino Acid Betaglycan-Binding Peptide Sequence of Inhibin α Subunit on Promoting Fertility in Female Rats

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    Inhibins suppress the FSH production in pituitary gonadotrope cells by robustly antagonizing activin signaling by competitively binding to activin type II receptors (ACTR II). The binding of inhibin A to ACTR II requires the presence of its co-receptor, namely, betaglycan. In humans, the critical binding site for betaglycan to inhibin A was identified on the inhibin α subunit. Through conservation analysis, we found that a core 13-amino-acid peptide sequence within the betaglycan-binding epitope on human inhibin α subunit is highly conserved across species. Based on the tandem sequence of such a conserved 13-amino-acid betaglycan-binding epitope (INHα13AA-T), we developed a novel inhibin vaccine and tested its efficacy in promoting female fertility using the female rat as a model. Compared with placebo-immunized controls, INHα13AA-T immunization induced a marked (p p p Fshb transcription and increased (p < 0.05) serum FSH and 17β-estradiol concentrations. In summary, active immunization against INHα13AA-T potently increased FSH levels, ovarian follicle development, ovulation rate and litter sizes, thus causing super-fertility in females. Therefore, immunization against INHα13AA is a promising alternative to the conventional approach of multiple ovulation and super-fertility in mammals

    circGprc5a Promoted Bladder Oncogenesis and Metastasis through Gprc5a-Targeting Peptide

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    Bladder cancer is a serious cancer in the world, especially in advanced countries. Bladder cancer stem cells (CSCs) drive bladder tumorigenesis and metastasis. Circular RNAs (circRNAs) are involved in many biological processes, but their roles in bladder oncogenesis and bladder CSCs are unclear. Here, we identified that circGprc5a is upregulated in bladder tumors and CSCs. circGpr5a knockdown impairs the self-renewal and metastasis of bladder CSCs, and its overexpression exerts an opposite role. circGpr5a has peptide-coding potential and functions through a peptide-dependent manner. circGprc5a-peptide binds to Gprc5a, a surface protein highly expressed in bladder CSCs. Gprc5a knockout inhibits the bladder CSC self-renewal and metastasis. circGprc5a-peptide-Gprc5a can be utilized to target bladder cancer and bladder CSCs. Keywords: bladder cancer, cancer stem cells, Gprc5a, peptid

    Effects of Targeted Suppression of Glutaryl-CoA Dehydrogenase by Lentivirus-Mediated shRNA and Excessive Intake of Lysine on Apoptosis in Rat Striatal Neurons

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    <div><p></p><p>In glutaric aciduria type 1 (GA1), glutaryl-CoA dehydrogenase (GCDH) deficiency has been shown to be responsible for the accumulation of glutaric acid and striatal degeneration. However, the mechanisms by which GA1 induces striatal degeneration remain unclear. In this study, we aimed to establish a novel neuronal model of GA1 and to investigate the effects of GCDH deficiency and lysine-related metabolites on the viability of rat striatal neurons. Thus we constructed a lentiviral vector containing short hairpin RNA targeted against the GCDH gene expression (lentivirus-shRNA) in neurons. A virus containing a scrambled short hairpin RNA construct served as a control. Addition of lysine (5 mmol/L) was used to mimic hypermetabolism. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Apoptosis was assessed using Hoechst33342 staining and Annexin V-PE/7-AAD staining. The mitochondrial membrane potential (MPP) was monitored using tetramethylrhodamine methyl ester. The expression levels of caspases 3, 8, and 9 were determined by Western blotting. We found that lentivirus-shRNA induced apoptosis and decreased MMP levels in neurons, and addition of 5 mmol/L lysine enhanced this effect markedly. Lentivirus-shRNA upregulated the protein levels of caspases 3 and 9 regardless of the presence of 5 mmol/L lysine. The expression level of caspase 8 was higher in neurons co-treated with lentivirus-shRNA and 5 mmol/L lysine than in control. Benzyloxy-carbonyl-Val-Ala-Asp(OMe)-fluoromethylketone, a pan-caspase inhibitor, blocked the apoptosis induced by lentivirus-shRNA and 5 mmol/L lysine to a great extent. These results indicate that the targeted suppression of GCDH by lentivirus-mediated shRNA and excessive intake of lysine may be a useful cell model of GA1. These also suggest that GA1-induced striatal degeneration is partially caspase-dependent.</p></div
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