Characterization of Novel Nucleic Acid Inhibitors (Aptamers) of Human Immunodeficiency Virus Reverse Transcriptase Selected Using a Primer-Free SELEX Approach

Aptamers are synthetic, single stranded nucleic acids that bind specifically to the target protein. Aptamers have many potential uses including therapeutic and diagnostic applications. Most aptamers are identified through standard SELEX (Systematic Evolution of Ligands by EXponential enrichment) procedures that include a starting pool of nucleic acids with a region of random nucleotides flanked by fixed sequences. A main disadvantage of the traditional SELEX is the potential for the fixed sequences to "bias" the selection by interacting with nucleotides in the random region of the oligonucleotide. I developed a novel primer-free SELEX method for isolating single strand 30 nt DNA aptamers from a random sequence pool for HIV reverse transcriptase (HIV-RT), in which selection occurs in the absence of any flanking, fixed nucleotides. Selected aptamers bound ~10-20 fold tighter than starting material to HIV-RT. The selected aptamer (PF1) contained a motif of four diguanosine repeats. PF1 was compared to two classes of HIV-RT aptamers: a G-quadruplex aptamer (R1T family) from Michalowski et al., Nuc. Acids Res. 2008, and a primer-template aptamer developed by our lab (37 NT SELEX, DeStefano and Nair, Oligonucleotides 2008). PF1 was an effective inhibitor of HIV-RT in vitro and bound to RT about as tightly as a full primer-template. Both the R1T and 37NT SELEX were more potent HIV-RT inhibitors. This may be due in part to their large size. Circular dichroism spectroscopy indicated that PF1 does not form a G-quadruplex, while the R1T, consistent with previous results, is a parallel G-quadruplex. The effect of the primer-template aptamer on HIV inhibition in cell culture was also studied. Low micromolar concentrations of aptamer in the absence of a transfection agent inhibited replication in Jurkat cells without significant cellular toxicity. However constructs with similar structure also inhibit HIV replication leading us to conclude that aptamer blockage of replication may be due to alteration of cellular pathways. In addition to the possible contribution in developing novel nucleic acid-based HIV inhibitors, aptamer selection experiments can also shed light on how RT interacts with nucleic acids both in vitro and in cellular models

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Ultralow-Power Alcohol Vapor Sensors Using Chemically Functionalized Multiwalled Carbon Nanotubes

Alcohol sensors, batch fabricated by forming bundles of chemically functionalized multiwalled carbon nanotubes (f-CNTs) across Au electrodes on SiO2/Si substrates using an AC electrophoretic technique, were developed for alcohol vapor detection using an ultralow input power of ∼ 0.01-1 μW, which is lower than the power required for most commercially available alcohol sensors by more than four orders of magnitude. The multiwalled carbon nanotubes (MWCNTs) have been chemically functionalized with the COOH groups by oxidation. We found that the sensors are selective with respect to flow from air, water vapor, and alcohol vapor. The sensor response is linear for alcohol vapor concentrations from 1 to 21 ppm with a detection limit of 0.9 ppm. The transient response of these sensors is experimentally shown to be ∼1 s and the variation of the responses at each concentration is within 10% for all of the tested sensors. The sensors could also easily be reset to their initial states by annealing the f-CNTs sensing elements at a current of 100-200 μA within ∼ 100-200 s. We demonstrated that the response of the sensors can be increased by one order of magnitude after adding the functional group COOH onto the nanotubes, i.e., from ∼0.9% of a bare MWCNTs sensor to ∼9.6% of an f-CNTs sensor with a dose of 21 ppm alcohol vapor. © 2007 IEEE

Plant alkaloid tetrandrine downregulates IκBα kinases-IκBα-NF-κB signaling pathway in human peripheral blood T cell

1. Plant alkaloid tetrandrine (Tet), purified from Chinese herb Han-Fang Chi, is a potent immunomodulator used to treat rheumatic disorders, silicosis and hypertension in mainland China. 2. We previously demonstrated that Tet effectively suppresses cytokine production and proliferation of CD28-costimulated T cells. In the present study, we investigated the possible involvement of nuclear factor kappa B (NF-κB) transcription factors, critical in CD28 costimulation, in Tet-mediated immunosuppression in human peripheral blood T cells. 3. We showed that Tet inhibited NF-κB DNA-binding activities induced by various stimuli, including CD28 costimulation. At equal molar concentrations, Tet was as strong as methotrexate in suppressing CD28-costimulated NF-κB activities. Since Tet itself did not affect NF-κB binding to its corresponding DNA sequence, the results suggested that Tet might regulate NF-κB upstream signaling molecules. 4. Further studies demonstrated that Tet could prevent the degradation of IκBα and inhibit nuclear translocation of p65 by blocking IκBα kinases α and β activities. In addition, the activation of mitogen-activated protein kinases such as c-jun N-terminal kinase, p38 and extracellular signal-regulated kinase and activator protein-1 DNA-binding activity were all downregulated by Tet. Transfection assays performed in purified human peripheral blood T cells also confirmed the inhibition of NF-κB transcriptional activity by Tet. 5. When four Tet analogues were readily compared, dauricine appeared to preserve the most potent inhibition on CD28-costimulated but not on H(2)O(2)-induced NF-κB DNA-binding activities. 6. Our results provide the molecular basis of immunomodulation of Tet for being a potential disease-modifying antirheumatic drug in the therapy of autoimmune disorders like rheumatoid arthritis

Effects of a culturally adapted counselling service for low-income ethnic minorities experiencing mental distress: a pragmatic randomised clinical trial

Background Culturally competent early mental health interventions for ethnic minorities (EMs) with no formal diagnoses are needed.Objectives To determine whether 8–12 weeks culturally adapted counselling (CAC) is better than waiting (waitlist (WL) group) to reduce depressive and anxiety symptoms and stress levels among EMs with elevated mental distress.Methods Hong Kong EMs with mild and above-mild mental distress were randomly assigned to CAC or WL in this pragmatic, randomised, WL-controlled trial. The CAC group received the intervention after randomisation and the WL group received the intervention after 8–12 weeks (T1). The prespecified primary outcomes were depressive and anxiety symptoms and stress levels measured by the Depression, Anxiety and Stress subscales of the Depression, Anxiety and Stress Scale (DASS-D, DASS-A and DASS-S, respectively) at postintervention (T1, 8–12 weeks).Findings A total of 120 participants were randomly assigned to either CAC (n=60) or WL (n=60), of whom 110 provided primary outcome data. At T1, CAC led to significantly lower depressive and anxiety symptom severity and stress levels compared with waiting, with unstandardised regression coefficients of −8.91 DASS-D points (95% CI −12.57 to −5.25; d=−0.90),–6.33 DASS-A points (95% CI −9.81 to −2.86; d=−0.68) and −8.60 DASS-S points (95% CI −12.14 to −5.06; d=−0.90).Conclusions CAC clinically outperformed WL for mild and above-mild levels of mental distress in EMs.Clinical implications Making CAC routinely available for EMs in community settings can reduce healthcare burden.Trial registration number NCT04811170

Can mixed pure hepatocellular carcinoma and germinoma arise together in the brain?

Intracranial germ-cell tumors (GCTs) represent 10–15% of all pediatric brain tumors in East Asia. There is a wide histopathological spectrum of intracranial GCTs. Germinomas and nongerminomatous GCTs are the two major classifications. It is difficult to distinguish different subtypes of intracranial GCTs based solely on imaging studies, however, some tumor markers, such as α-fetoprotein or β-human chorionic gonadotropin, are helpful for diagnosis. In this study we present the case of a 13-year-old girl with an intracranial mixed GCT containing a hepatocellular carcinoma and germinoma without a primary liver tumor. Based on this unique pathological diagnosis, a series of treatments were applied, including surgery for gross tumor removal, adjuvant radiotherapy, and chemotherapy. Long-term follow up indicates fair disease control

Real-world efficacy of biological agents in moderate-to-severe plaque psoriasis: An analysis of 75 patients in Taiwan.

BackgroundReal-world clinical data on psoriasis patients receiving different biological agents is needed, especially in Asian populations.ObjectivesOur aim is to compare and analyze the efficacy and safety profile of four biological agents (etanercept, adalimumab, ustekinumab and secukinumab) in a real-world setting in Taiwan.MethodsWe retrospectively analyzed the clinical data of all patients with moderate-to-severe plaque psoriasis (Psoriasis Area and Severity Index (PASI) ≥ 10) who received etanercept, adalimumab, ustekinumab or secukinumab between January 2011 and December 2018 in a tertiary hospital in Taiwan.ResultsA total of 119 treatment episodes in 75 patients were included in this study. Ustekinumab was used in 49 treatment episodes, followed by secukinumab in 46 treatment episodes, adalimumab in 14 treatment episodes and etanercept in 10 treatment episodes. The proportion of the biologic-naïve was highest in etanercept (100%) and lowest in secukinumab (23.9%). The PASI-75, -90 and -100 were the highest in secukinumab (91.3%, 82.6%, 41.3%, respectively), followed by ustekinumab (79.6%, 44.9%, 16.3%), adalimumab (64.3%, 28.6%, 7.1%) and etanercept (50.0%, 30.0%, 0%). The rate of adverse events that required treatment was highest for secukinumab (15.2%), followed by adalimumab (14.3%), ustekinumab (8.2%), and etanercept (0%), including 4 cases of infections, 2 cases of cardiovascular diseases and 4 cases of cancers.ConclusionsThis real world data showed differential efficacy and safety of the four biological agents