This paper contributes to the post-Covid urban tourism debate. It focuses on how cities respond to the pandemic asking how and to what extent urban destination brands are leverged by city marketers for coping with the Covid-19 crisis. It explores city brand values and attributes change as a component of the urban approach to facing the current crisis.
View Article and Find Full Text PDF. Low-intensity transcranial ultrasound stimulation (TUS) is a promising non-invasive brain stimulation (NIBS) technique. TUS can reach deeper areas and target smaller regions in the brain than other NIBS techniques, but its application in humans is hampered by the lack of a straightforward and reliable procedure to predict the induced ultrasound exposure.
View Article and Find Full Text PDFBackground: Low-intensity transcranial focused ultrasound stimulation is a promising candidate for noninvasive brain stimulation and accurate targeting of brain circuits because of its focusing capability and long penetration depth. However, achieving a sufficiently high spatial resolution to target small animal sub-regions is still challenging, especially in the axial direction.
Objective: To achieve high axial resolution, we designed a dual-crossed transducer system that achieved high spatial resolution in the axial direction without complex microfabrication, beamforming circuitry, and signal processing.
Objective: Low-intensity transcranial ultrasound stimulation (TUS) is emerging as a non-invasive brain stimulation technique with superior spatial resolution and the ability to reach deep brain areas. Medical image-based computational modeling could be an important tool for individualized TUS dose control and targeting optimization, but requires further validation. This study aims to assess the impact of the transducer model on the accuracy of the simulations.
View Article and Find Full Text PDFBackground: Low-intensity transcranial focused ultrasound stimulation (TFUS) holds great promise as a highly focal technique for transcranial stimulation even for deep brain areas. Yet, knowledge about the safety of this novel technique is still limited.
Objective: To systematically review safety related aspects of TFUS.
Background: Current transcranial ultrasound stimulation for small animal in vivo experiment is limited to acute stimulation under anesthesia in stereotaxic fixation due to bulky and heavy curved transducers.
Methods: We developed a miniaturized ultrasound ring array transducer which is capable of invoking motor responses through neuromodulation of freely-moving awake mice.
Results: The developed transducer is a 32-element, 183-kHz ring array with a weight of 0.
BMS-791325 is a nonnucleoside inhibitor of hepatitis C virus (HCV) NS5B polymerase with low-nanomolar potency against genotypes 1a (50% effective concentration [EC50], 3 nM) and 1b (EC50, 7 nM) in vitro. BMS-791325 safety, pharmacokinetics, and antiviral activity were evaluated in a double-blind, placebo-controlled, single-ascending-dose study in 24 patients (interferon naive and experienced) with chronic HCV genotype 1 infection, randomized (5:1) to receive a single dose of BMS-791325 (100, 300, 600, or 900 mg) or placebo. The prevalence and phenotype of HCV variants at baseline and specific posttreatment time points were assessed.
View Article and Find Full Text PDFBackground: It is necessary to evaluate the impact of hepatic impairment on the pharmacokinetic profile of direct-acting antiviral agents for the treatment of HCV infection.
Methods: In this open-label, parallel group, multiple-dose study subjects (aged 18-70 years with a body mass index <35 kg/m(2)) with mild (n=6), moderate (n=6) and severe hepatic impairment (n=4) received asunaprevir 200 mg twice daily; healthy subjects (n=12) were matched (age, weight, gender) 1:1 to the first 4 subjects in each hepatic impairment group to act as controls. Pharmacokinetic sampling and analyses were performed on days 1 and 7 of dosing.
Background & Aims: Patients with chronic hepatitis C virus (HCV) infection and prior null response (<2 log HCV RNA decline after ⩾ 12 weeks of PegIFN/RBV) have limited options. We evaluated daclatasvir plus once- or twice-daily asunaprevir in non-cirrhotic genotype 1 null responders.
Methods: In this randomized, phase 2a, open-label, 24-week treatment study, 101 patients received daclatasvir (60 mg) once-daily.
Background: All-oral combination therapy is desirable for patients with chronic hepatitis C virus (HCV) infection. We evaluated daclatasvir (an HCV NS5A replication complex inhibitor) plus sofosbuvir (a nucleotide analogue HCV NS5B polymerase inhibitor) in patients infected with HCV genotype 1, 2, or 3.
Methods: In this open-label study, we initially randomly assigned 44 previously untreated patients with HCV genotype 1 infection and 44 patients infected with HCV genotype 2 or 3 to daclatasvir at a dose of 60 mg orally once daily plus sofosbuvir at a dose of 400 mg orally once daily, with or without ribavirin, for 24 weeks.
Background & Aims: The combination of peginterferon and ribavirin with telaprevir or boceprevir is the standard treatment of hepatitis C virus (HCV) genotype 1 infection. However, these drugs are not well tolerated because of their side effects and suboptimal virologic responses. In a phase 2a, open-label study, we examined the safety and efficacy of an interferon-free, ribavirin-free regimen of direct-acting antivirals, comprising daclatasvir (an NS5A replication complex inhibitor), asunaprevir (an NS3 protease inhibitor), and BMS-791325 (a non-nucleoside NS5B inhibitor), in patients with chronic HCV infection.
View Article and Find Full Text PDFAsunaprevir (BMS-650032, ASV) is a potent, selective hepatitis C virus (HCV) NS3 protease inhibitor in clinical evaluation for chronic hepatitis C treatment. ASV pharmacokinetics were evaluated in four single- and multiple-ascending-dose studies in healthy subjects or subjects with HCV genotype 1 infection and in human mass balance and food-effect studies. Median Tmax was 2-4 hours.
View Article and Find Full Text PDFAntimicrob Agents Chemother
July 2012
Asunaprevir (BMS-650032) is a potent hepatitis C virus (HCV) NS3 protease inhibitor demonstrating efficacy in alfa interferon-sparing, direct-acting antiviral dual-combination regimens (together with the NS5A replication complex inhibitor daclatasvir) in patients chronically infected with HCV genotype 1b. Here, we describe a comprehensive in vitro genotypic and phenotypic analysis of asunaprevir-associated resistance against genotypes 1a and 1b using HCV replicons and patient samples obtained from clinical studies of short-term asunaprevir monotherapy. During genotype 1a resistance selection using HCV replicons, the primary NS3 protease substitutions identified were R155K, D168G, and I170T, which conferred low- to moderate-level asunaprevir resistance (5- to 21-fold) in transient-transfection susceptibility assays.
View Article and Find Full Text PDFHepatitis C virus (HCV) protease inhibitors combined with pegylated alfa interferon-ribavirin have demonstrated improved efficacy compared with pegylated alfa interferon-ribavirin alone for the treatment of chronic hepatitis C. Asunaprevir (BMS-650032), a novel HCV NS3 protease inhibitor in clinical development, was evaluated for safety, antiviral activity, and resistance in four double-blind, placebo-controlled, sequential-panel, single- and multiple-ascending-dose (SAD and MAD) studies in healthy subjects or subjects with chronic HCV genotype 1 infection. In SAD studies, subjects (healthy or with chronic HCV infection) were randomized to receive asunaprevir in dose groups of 10 to 1,200 mg or a placebo.
View Article and Find Full Text PDFBackground: Patients with chronic hepatitis C virus (HCV) infection who have not had a response to therapy with peginterferon and ribavirin may benefit from the addition of multiple direct-acting antiviral agents to their treatment regimen.
Methods: This open-label, phase 2a study included an exploratory cohort of 21 patients with chronic HCV genotype 1 infection who had not had a response to previous therapy (i.e.
The inability of hepatitis C virus (HCV) to replicate in cell culture has hindered the discovery of antiviral agents against this virus. One of the biggest challenges has been to find a model that allows one to easily and accurately quantify the level of HCV RNA replication that is occurring inside the cell. In an attempt to solve this problem, we have created a plasmid pMJ050 that encodes a chimeric 'HCV-like' RNA that can act as a reporter for HCV RNA replication.
View Article and Find Full Text PDFThis study was performed to test the hypothesis that cytotoxic T lymphocyte (CTL) selection of hepatitis C virus (HCV) escape variants plays a role in HCV persistence. The peripheral blood CTL responsiveness of patients with well-established chronic hepatitis C to a panel of 10 prototype HCV peptides (genotype 1a) was compared with the corresponding sequences encoded by the infecting viruses in each patient. Variant viral peptide sequences were threefold more frequent in the presence of a CTL response than in its absence, and CTL responses were detected nearly twice as often in association with variant rather than with prototype viral peptide sequences.
View Article and Find Full Text PDFTransgenic mice have been produced that express the hepatitis C virus (HCV) core protein in the liver under the transcriptional control of the mouse major urinary protein promoter. These animals express the full length core protein in cytoplasm of their hepatocytes at levels comparable to those detected in naturally infected patients, without histological or biochemical evidence of liver disease or hepatocellular carcinoma. This contrasts with recent reports that HCV core protein can transform NIH 3T3 cells and cooperates with H-ras to transform primary rat fibroblasts in vitro.
View Article and Find Full Text PDFIt is widely believed that the hepatitis B virus (HBV) is completely cleared by antiviral antibodies and specific cytotoxic T lymphocytes (CTLs) during acute viral hepatitis. We now demonstrate that traces of HBV are often detectable in the blood for many years after clinical recovery from acute hepatitis, despite the presence of serum antibodies and HBV-specific CTLs, which can be present at acute-stage levels. The strength of the CTL response to HBV following clinical recovery correlates with persistence of HBV DNA.
View Article and Find Full Text PDFIn this study, we examined the ability of the hepatitis B virus (HBV) precore, envelope, and X gene products to modulate HBV replication in the livers of transgenic mice that replicate the virus. Hepatic HBV replication was not affected by overexpression of the envelope or X gene products when these animals were crossed with transgenic mice that express the corresponding viral genes in the hepatocyte. Overexpression of the precore protein, however, eliminated nucleocapsid particles from the cytoplasm of the hepatocytes and abolished HBV replication without affecting the hepatic steady-state content of pregenomic HBV RNA.
View Article and Find Full Text PDFThe clinical case of a 45-year-old patient referred to us for chest pain and with clinical examination and ECG negative for ischaemic damage, is reported. The patient, hospitalised in a bed without an ECG monitor, presented heart failure due to ventricular fibrillation. He was re-examined first with ventilation and EMC and then with defibrillation.
View Article and Find Full Text PDFIt has been suggested that immune selection pressure exerted by the cytotoxic T lymphocyte (CTL) response could be responsible for viral persistence during chronic hepatitis B virus infection. To address this question, in the current study we compared the DNA and amino acid sequences of, and the CTL responses to, multiple HLA-A2-restricted CTL epitopes in the hepatitis B virus in several HLA-A2-positive patients with acute and chronic hepatitis. Our results indicate that the CTL response to these epitopes is barely detectable in the majority of patients with chronic hepatitis.
View Article and Find Full Text PDFThe HLA class I-restricted cytotoxic T lymphocyte (CTL) response is a major defense mechanism in viral infections. It has been suggested that the CTL response may contribute to viral clearance and liver cell injury during hepatitis C virus (HCV) infection. To test this hypothesis requires an understanding of the characteristics of HCV-specific cytotoxic effector cells and identification of the target antigens to which they respond.
View Article and Find Full Text PDFContrary to current opinion, the disappearance of hepatitis B surface antigen (HBsAg) from the serum, the development of anti-HBs antibodies, and normalization of liver function may not reflect complete virological recovery from acute hepatitis B virus (HBV) infection. By using the polymerase chain reaction (PCR), in the current study we demonstrate long-term persistence of HBV DNA in the serum and peripheral blood mononuclear cells (PBMC) of four patients for up to 70 mo after complete clinical, biochemical, and serological recovery from acute viral hepatitis. Serum HBV DNA reactivity co-sedimented with HBsAg in sucrose gradients, and it displayed the size and density characteristics of naked core particles and intact HBV virions, presumably contained within circulating immune complexes in these anti-HBs antibody-positive sera.
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