Neutralizing antibody response during acute and chronic hepatitis C virus infection

Little is known about the role of Abs in determining the outcome of hepatitis C virus (HCV) infection. By using infectious retroviral pseudotypes bearing HCV glycoproteins, we measured neutralizing Ab (nAb) responses during acute and chronic HCV infection. In seven acutely infected health care workers, only two developed a nAb response that failed to associate with viral clearance. In contrast, the majority of chronically infected patients had nAbs. To determine the kinetics of strain-specific and crossreactive nAb emergence, we studied patient H, the source of the prototype genotype 1a H77 HCV strain. An early weak nAb response, specific for the autologous virus, was detected at seroconversion. However, neutralization of heterologous viruses was detected only between 33 and 111 weeks of infection. We also examined the development of nAbs in 10 chimpanzees infected with H77 clonal virus. No nAb responses were detected in three animals that cleared virus, whereas strain-specific nAbs were detected in six of the seven chronically infected animals after approximately 50 weeks of infection. The delayed appearance of high titer crossreactive nAbs in chronically infected patients suggests that selective mechanism(s) may operate to prevent the appearance of these Abs during acute infection. The long-term persistence of these nAbs in chronically infected patients may regulate viral replication

Phase I study of nab-paclitaxel, gemcitabine, and bevacizumab in patients with advanced cancers.

BackgroundWe performed a phase I modified 3 + 3 dose escalation study to evaluate the safety and activity of bevacizumab plus gemcitabine and nab-paclitaxel in patients with advanced solid tumours.MethodsPatients were given fixed dose gemcitabine plus increasing doses of nab-paclitaxel and bevacizumab. Toxicity, response, and association with VEGF polymorphism was analysed.ResultsThe study enrolled 110 patients who had undergone a median of 3 prior lines of therapy. The median age was 60 years (range, 17-85 years), and 55 patients (50%) had gemcitabine-refractory disease. We observed 3 dose-limiting toxicities during dose escalation and 3 DLTs in expansion cohorts. Dose escalation to 150 mg/m2 nab-paclitaxel and 15 mg/kg bevacizumab with 1000 mg/m2 of gemcitabine was well tolerated with no MTD. One patient with gemcitabine-refractory peritoneal papillary carcinoma had a complete response, 13 patients (13%) had partial responses, and 54 patients (52%) had stable disease ≥12 weeks. Exploratory VEGF single nucleotide polymorphism (SNP) analysis was performed on 13 patients.ConclusionsThe combination of gemcitabine, nab-paclitaxel, and bevacizumab is safe, well-tolerated, and has activity in advanced malignancies, including gemcitabine-refractory tumours. Based on this study, the recommended phase 2 dose is gemcitabine 1000 mg/m2, nab-paclitaxel 125 mg/m2, and bevacizumab 15 mg/kg. VEGF polymorphism data should be evaluated in future bevacizumab-based trials

Characterization of nuclear polyadenylated RNA-binding proteins in Saccharomyces cerevisiae.

To study the functions of heterogeneous nuclear ribonucleoproteins (hnRNPs), we have characterized nuclear polyadenylated RNA-binding (Nab) proteins from Saccharomyces cerevisiae. Nab1p, Nab2p, and Nab3p were isolated by a method which uses UV light to cross-link proteins directly bound to poly(A)+ RNA in vivo. We have previously characterized Nab2p, and demonstrated that it is structurally related to human hnRNPs. Here we report that Nab1p is identical to the Np13p/Nop3p protein recently implicated in both nucleocytoplasmic protein shuttling and pre-rRNA processing, and characterize a new nuclear polyadenylated RNA-binding protein, Nab3p. The intranuclear distributions of the Nab proteins were analyzed by three-dimensional immunofluorescence optical microscopy. All three Nab proteins are predominantly localized within the nucleoplasm in a pattern similar to the distribution of hnRNPs in human cells. The NAB3 gene is essential for cell viability and encodes an acidic ribonucleoprotein. Loss of Nab3p by growth of a GAL::nab3 mutant strain in glucose results in a decrease in the amount of mature ACT1, CYH2, and TPI1 mRNAs, a concomitant accumulation of unspliced ACT1 pre-mRNA, and an increase in the ratio of unspliced CYH2 pre-mRNA to mRNA. These results suggest that the Nab proteins may be required for packaging pre-mRNAs into ribonucleoprotein structures amenable to efficient nuclear RNA processing

The Nab Experiment: A Precision Measurement of Unpolarized Neutron Beta Decay

Neutron beta decay is one of the most fundamental processes in nuclear physics and provides sensitive means to uncover the details of the weak interaction. Neutron beta decay can evaluate the ratio of axial-vector to vector coupling constants in the standard model, $\lambda = g_A / g_V$, through multiple decay correlations. The Nab experiment will carry out measurements of the electron-neutrino correlation parameter $a$ with a precision of $\delta a / a = 10^{-3}$ and the Fierz interference term $b$ to $\delta b = 3\times10^{-3}$ in unpolarized free neutron beta decay. These results, along with a more precise measurement of the neutron lifetime, aim to deliver an independent determination of the ratio $\lambda$ with a precision of $\delta \lambda / \lambda = 0.03\%$ that will allow an evaluation of $V_{ud}$ and sensitively test CKM unitarity, independent of nuclear models. Nab utilizes a novel, long asymmetric spectrometer that guides the decay electron and proton to two large area silicon detectors in order to precisely determine the electron energy and an estimation of the proton momentum from the proton time of flight. The Nab spectrometer is being commissioned at the Fundamental Neutron Physics Beamline at the Spallation Neutron Source at Oak Ridge National Lab. We present an overview of the Nab experiment and recent updates on the spectrometer, analysis, and systematic effects.Comment: Presented at PPNS201

Prognostic factors of survival in patients treated with nab-paclitaxel plus gemcitabine regimen for advanced or metastatic pancreatic cancer: A single institutional experience.

The objectives of this study were to evaluate the effectiveness of nab-paclitaxel plus gemcitabine (NAB-P/GEM) regimen in an unselected population of patients with advanced inoperable or metastatic pancreatic cancer (PC), and to identify the prognostic factors influencing overall survival (OS). EXPERIMENTAL DESIGN: Patients with age < 85 years, ECOG-performance status (PS) < 3, and adequate renal, hepatic and hematologic function were eligible. NAB-P (125 mg/m2) and GEM (1000 mg/m2) day 1,8,15 every 4 weeks were employed for 3-6 cycles or until highest response. RESULTS: Overall, 147 cycles (median 4, range 1-11 cycles) were administered on thirty-seven consecutive patients (median 66 years old, range 40-82) treated. The median overall progression-free survival and OS were 6.2 and 9.2 months, respectively. The G 3-4 dose-limiting toxicity were neutropenia (20.7%), severe anemia (17.2%), and cardiovascular toxicity (10.3%). PS, number of cycles, baseline CA 19-9 and LDH serum levels, were found to be significantly related to OS. The multivariate analysis showed that both number of cycles (HR = 9.14, 95% CI 1.84-45.50, p = 0.001) and PS (HR = 13.18, 95% CI 2.73-63.71, p = 0.001) were independently associated with OS. CONCLUSION: NAB-P/GEM regimen should be used in all patients with advanced or metastatic PC, with the exception of those with serious contraindications to chemotherapy, such as severe renal or hepatic impairment or major cardiovascular diseases

Prospective study on nanoparticle albumin-bound paclitaxel in advanced breast cancer. Clinical results and biological observations in taxane-pretreated patients

Background: There is a deep need to improve the care of metastatic breast cancer (MBC) patients, since even today it remains an incurable disease. Taxanes are considered the most effective cytotoxic drugs for the treatment of MBC, both in monotherapy and in combined schedules, but the need for synthetic solvents contributes to the severe toxicities and may have a negative impact on the efficacy. Nanoparticle albumin-bound paclitaxel (Nab-paclitaxel) is a colloidal suspension of paclitaxel and human serum albumin initially developed to avoid the toxicities associated with conventional taxanes. Patients and methods: The aim of this prospective, single-center open-label, noncomparative study was to evaluate the efficacy and safety of nab-paclitaxel in MBC patients pretreated with taxanes. The patients were treated with nab-paclitaxel as a single agent, 260 mg/m2 on day 1 of each 3-week cycle or 125 mg/m2 weekly. The primary endpoint was the overall response rate (ORR). Secondary objectives were duration of response, clinical benefit rate, progression-free survival (PFS), overall survival, and safety. Results: A total of 42 patients (median age 48 years, median Eastern Cooperative Oncology Group performance status 0, triple-negative MBC 19%, all pretreated with a taxane-based therapy, mainly in advanced disease) were enrolled in the study. The ORR was 23.8%, including one complete response (2.4%) and nine partial responses (21.4%); the disease control rate was 50%. The median duration of response was 7.2 months. After a median follow-up of 9 months, the median PFS was 4.6 months. ORR and PFS were similar irrespective of the previous chemotherapy lines, metastatic sites, and biomolecular expression. Nab-paclitaxel was well tolerated, and the most frequent treatment-related toxicities were mild to moderate (grades 1–2). Conclusion: This real-life study shows that nab-paclitaxel has a significant antitumor activity and a manageable safety profile in patients pretreated with taxanes and experiencing a treatment failure after at least one line of chemotherapy

Serological evidence for Japanese encephalitis and West Nile virus infections in domestic birds in Cambodia

Mosquito-borne flaviviruses with an enzootic transmission cycle like Japanese encephalitis virus (JEV) and West Nile virus (WNV) are a major public health concern. The circulation of JEV in Southeast Asia is well-documented, and the important role of pigs as amplification hosts for the virus is long known. The influence of other domestic animals especially poultry that lives in high abundance and close proximity to humans is not intensively analyzed. Another understudied field in Asia is the presence of the closely related WNV. Such analyses are difficult to perform due to the intense antigenic cross-reactivity between these viruses and the lack of suitable standardized serological assays. The main objective of this study was to assess the prevalence of JEV and WNV flaviviruses in domestic birds, detailed in chickens and ducks, in three different Cambodian provinces. We determined the flavivirus seroprevalence using an hemagglutination inhibition assay (HIA). Additionally, we investigated in positive samples the presence of JEV and WNV neutralizing antibodies (nAb) using foci reduction neutralization test (FRNT). We found 29% (180/620) of the investigated birds positive for flavivirus antibodies with an age-depended increase of the seroprevalence (OR = 1.04) and a higher prevalence in ducks compared to chicken (OR = 3.01). Within the flavivirus-positive birds, we found 43% (28/65) with nAb against JEV. We also observed the expected cross-reactivity between JEV and WNV, by identifying 18.5% double-positive birds that had higher titers of nAb than single-positive birds. Additionally, seven domestic birds (10.7%) showed only nAb against WNV and no nAb against JEV. Our study provides evidence for an intense JEV circulation in domestic birds in Cambodia, and the first serological evidence for WNV presence in Southeast Asia since decades. These findings mark the need for a re-definition of areas at risk for JEV and WNV transmission, and the need for further and intensified surveillance of mosquito-transmitted diseases in domestic animals