[A new challenge in clinical practice: resistance to directly acting antivirals in hepatitis C treatment]

Directly acting antivirals (DAAs) is a major treatment of hepatitis C virus (HCV) overseas. But DAAs resistance is getting more and more clinicians' attention. DAAs have not been approved in China to date, even though some of them are in clinical trials. However, a good knowledge of DAAs resistance is important on optimizing HCV treatment regimens, increasing sustained virological response (SVR) and decreasing treatment failure in clinical. In this review, DAAs resistance mechanism and virologic barrier to resistance, the prevalence of pre-existing DAAs resistance-associated variants (RAVs), the impact of RAVs on treatment outcome, the options of treatment regimens after resistance and drug resistance testing are discussed, hoping to provide some help for DAAs' standardized treatment in China in the future.

[Current status of treatment of chronic hepatitis C and related challenges in the "Pre-DAA Era" in China]

The condition of chronic hepatitis C is becoming more and more serious in China, and its disease burden and social and economic burdens are growing heavier. Currently, the standard regimen for the treatment of chronic hepatitis C in China is the PR regimen, namely pegylated interferon combined with ribavirin; however, there are still many shortcomings in this regimen. In the world, there is rapid clinical progress in direct-acting antiviral agents (DAAs) for the treatment of hepatitis C, and DAAs will soon be approved and marketed in China, ushering the "DAA Era" of hepatitis C treatment. This article reviews the disease burden of chronic hepatitis C and problems in the standard regimen in clinical treatment and briefly introduces the advantages and challenges of DAAs regimens, in order to provide a reference for the upcoming "DAA Era" of hepatitis C treatment in China.

Metabolic and spatio-taxonomic response of uncultivated seafloor bacteria following the Deepwater Horizon oil spill

The release of 700 million liters of oil into the Gulf of Mexico over a few months in 2010 produced dramatic changes in the microbial ecology of the water and sediment. Here, we reconstructed the genomes of 57 widespread uncultivated bacteria from post-spill deep-sea sediments, and recovered their gene expression pattern across the seafloor. These genomes comprised a common collection of bacteria that were enriched in heavily affected sediments around the wellhead. Although rare in distal sediments, some members were still detectable at sites up to 60 km away. Many of these genomes exhibited phylogenetic clustering indicative of common trait selection by the environment, and within half we identified 264 genes associated with hydrocarbon degradation. Alkane degradation ability was near ubiquitous among candidate hydrocarbon degraders, whereas just three harbored elaborate gene inventories for the degradation of alkanes and aromatic and polycyclic aromatic hydrocarbons (PAHs). Differential gene expression profiles revealed a spill-promoted microbial sulfur cycle alongside gene upregulation associated with PAH degradation. Gene expression associated with alkane degradation was widespread, although active alkane degrader identities changed along the pollution gradient. Analyses suggest that a broad metabolic capacity to respond to oil inputs exists across a large array of usually rare indigenous deep-sea bacteria.

Concurrent chemoradiotherapy with weekly nedaplatin versus radiotherapy alone in elderly patients with non-small-cell lung cancer

PURPOSE

We conduct this study to compare the efficacy and toxicity of intensity-modulated radiotherapy (IMRT) concurrent weekly nedaplatin (NDP) versus IMRT alone in the stage III/IV non-surgical elderly patients with non-small-cell lung cancer (NSCLC).

METHODS

117 patients were enrolled into our study. The patients were assigned into two different groups: radiotherapy (RT) group and chemoradiotherapy (CRT) group. Patients in RT group were treated with IMRT at a single daily dose of 2 Gy for 5 days per week, totally 52-66 Gy. The CRT group, IMRT concurrent weekly NDP at a dose of 25 mg/m².

RESULTS

In CRT group, the median survival was 11.0 months (95% confidence interval [CI], 8.894-13.106 months) and in RT group, it was 7.0 months (95% CI 5.771-8.229 months). The 1-year, 2-year, 3-year, survival rates in the combined treatment arm were higher than the radiation therapy arm (46.8 vs 25.9%, 25.1 vs 11.8%, 14.7 vs 8.0%; p < 0.001). The Cox's multiple regression analysis showed that CRT had significantly better overall survival than RT (HR 0.523; 95.0% CI 0.338-0.807; p = 0.003). The objective response rate provided that 73.3% treated with CRT compared with 51.1% (p = 0.018) received RT alone. Of the hematologic toxicities, leukocytes (35.0 vs 0%; p < 0.001), neutrophils (33.3 vs 0%; p < 0.001) were significantly more common in the CRT group than the RT group.

CONCLUSIONS

We first discovered that NDP concurrent IMRT for treating stage III/IV non-surgical elderly patients with NSCLC was good curative effect of better objective response rate and well-tolerated. However, within the low number of patients, only stage IV gained a survival benefit.

Molecular and hydrodynamic properties of human epidermal growth factor receptor HER2 extracellular domain and its homodimer: Experiments and multi-scale simulations

BACKGROUND

In a broad range of human carcinomas gene amplification leads to HER2 overexpression, which has been proposed to cause spontaneous dimerization and activation in the absence of ligand. This makes HER2 attractive as a therapeutic target. However, the HER2 homodimerization mechanism remains unexplored. It has been suggested that the "back-to-back" homodimer does not form in solution. Notwithstanding, very recently the crystal structure of the HER2 extracellular domain homodimer formed with a "back-to-head" interaction has been resolved. We intend to explore the existence of such interactions.

METHODS

A combination of experiments, molecular dynamics and hydrodynamic modeling were used to monitor the transport properties of HER2 in solution.

RESULTS & CONCLUSIONS

We have detected the HER2 extracellular domain homodimer in solution. The results show a high degree of molecular flexibility, which ultimately leads to quite higher values of the intrinsic viscosity and lower values of diffusion coefficient than those corresponding to globular proteins. This flexibility obeys to the open conformation of the receptor and to the large fluctuations of the different domains. We also report that for obtaining the correct hydrodynamic constants from the modeling one must consider the glycosylation of the systems.

GENERAL SIGNIFICANCE

Conformational features of epidermal growth factor receptors regulate their hydrodynamic properties and control their activity. It is essential to understand the dynamics of these systems and the role of the specific domains involved. To find biophysical correlations between dynamics and macroscopic transport properties is of general interest for researches working in this area. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue.

Clinical application of a gadolinium-based capsule as an MRI contrast agent in slow transit constipation diagnostics

BACKGROUND

As a traditional method for the assessment of colon dynamics, radio-opaque markers (ROMs) are limited in clinical use because of their ionizing radiation. We compared the accuracy and applicability of gadolinium-based capsules with ROMs in the measurement of colon dynamics in healthy controls and slow transit constipation (STC) patients.

METHODS

Seven patients with STC and nine healthy controls under a normal diet orally consumed ROMs and gadolinium-based capsules simultaneously. All subjects underwent X-ray and magnetic resonance imaging (MRI). Healthy control images were acquired at 12, 24, and 48 h, and STC patient images were acquired at 24, 48, and 72 h. The scores based on the position of the labeling capsules and ROMs in the colon and the colon transit times (CTTs) in the two groups were compared.

KEY RESULTS

The CTTs obtained via the ROMs were 34.7±17.4 and 67.3±6.5 h in the healthy controls and STC patients, respectively (P<.05). The CTTs obtained via MRI were 30.9±15.9 and 74.1±7.2 h in the healthy controls and STC patients, respectively (P<.05). The CTTs of the STC patients were significantly longer than the healthy controls. The correlation (r_s ) between the scores based on the position of the labeling capsule and ROMs in the healthy group and the STC patients was .880 (P<.05) and .889 (P<.05), respectively.

CONCLUSIONS AND INFERENCES

As a MRI contrast label, gadolinium-based capsules exhibit results comparable to ROMs in colon motility measurements.

[Role of glucose-6-phosphate dehydrogenase in hepatitis B virus replication and its possible mechanism of action]

OBJECTIVE

To investigate the role of glucose-6-phosphate dehydrogenase (G6PD) in hepatitis B virus (HBV) replication and its possible mechanism of action.

METHODS

Tissue microarray, quantitative real-time PCR, and Western blot were performed to analyze the differences in G6PD expression levels in the HBV-positive and HBV-negative liver tissues, HepG2.2.15 cells, and HepG2 cells. The siRNA transfection technique was used to knock down G6PD gene in HepG2.2.15 cells for 48 hours. Chemiluminescence was used for HBsAg and HBeAg quantification in supernatant, and quantitative real-time PCR was used to measure HBV DNA, type I interferon (IFN), and downstream IFN-stimulated genes. The t-test was used for comparison between groups.

RESULTS

G6PD expression was significantly upregulated in the HBV-positive liver tissues and cells compared with HBV-negative liver tissues and cells, and the stain intensity and immunohistochemical scores were 89.69±54.92 and 31.90±18.62, respectively (P < 0.05). After G6PD expression in HepG2.2.15 cells was interfered by siRNA, the quantitative levels of HBV DNA, HBsAg, and HBeAg in supernatant were reduced significantly, and the mRNA expression levels of IFNα1, IFNβ1, and five downstream IFN-stimulated genes (OAS1, ISG15, OAS3, EIF2α, and PKR) increased significantly (all P < 0.05).

CONCLUSION

G6PD plays a vital role in HBV replication, and its mechanism of action in regulating HBV replication may be related to type I IFN signaling pathway.

Siglec-7 Defines a Highly Functional Natural Killer Cell Subset and Inhibits Cell-Mediated Activities

Sialic acid-binding immunoglobulin-like lectin-7 (Siglec-7) is an inhibitory receptor expressed on natural killer (NK) cells. In this study, we investigated the relationship between Siglec-7 expression and NK cell functions. Siglec-7 was highly expressed on NK cells and was preferentially expressed by mature NK cells from peripheral blood of healthy adults. Siglec-7(+) NK cells displayed higher levels of activating receptors CD38, CD16, DNAM1, NKp30 and NKp46, but lower levels of inhibitory receptors such as NKG2A and CD158b, compared with Siglec-7(-) NK cells. Functional tests showed that Siglec-7(+) NK cells displayed more CD107a degranulation and IFN-γ production than Siglec-7(-) NK cells. Siglec-7 inhibited NK cell functions when interacting with specific antibodies. These data suggest that Siglec-7 defines a highly functional NK cell subset and suppresses NK cell-mediated functions when cross-linked with specific antibodies.

A rational catalyst design of CO oxidation using the bonding contribution equation

A rational design of heterogeneous catalysts is an important yet challenging task.

Formulating the bonding contribution equation in heterogeneous catalysis: a quantitative description between the surface structure and adsorption energy

The relation between the surface structure and adsorption energy of adsorbates is of great importance in heterogeneous catalysis.

Selective hydrogenation of acetylene over Cu(211), Ag(211) and Au(211): Horiuti–Polanyi mechanism vs. non-Horiuti–Polanyi mechanism

The Horiuti–Polanyi and non-Horiuti–Polanyi mechanisms are thoroughly examined and compared for the hydrogenation of C₂ hydrocarbons using DFT calculations.

Significant enhancement of the selectivity of propylene epoxidation for propylene oxide: a molecular oxygen mechanism

As an attractive and environmentally friendly process for propylene oxide (PO) production, direct epoxidation of propylene (DEP) with molecular oxygen catalyzed by metal-based catalysts such as Ag and Cu has drawn much attention, but remains one of the biggest challenges in chemistry.

Cryomicroscopic analysis of intracellular ice formation in porcine iliac endothelial cells upon cooling

　　BACKGROUND: Intracellular ice formation (IIF) plays an important role in cryopreservation and cryosurgery. IIF in porcine iliac endothelial cells (PIECs) has not been fully investigated.

OBJECTIVE

To analyze the phenomenon of IIF in PIECs during freezing.

MATERIALS AND METHODS

The cryomicroscopy system was used for observation of the cell morphology and for the count of IIF during freezing, while the theoretical model for probability IIF (PIF) was used to determine the nucleation kinetic and thermodynamic parameters.

RESULTS

PIF was observed at 40, 80 and 100 degree C/min upon cooling and 100 degree C/min upon warming, in the presence and absence of 1 M dimethyl sulfoxide (Me2SO). The kinetic and thermodynamic parameters were obtained by fitting the PIF model to experimental data.

CONCLUSION

PIF increases along with the increased cooling rate. The addition of 1 M dimethyl sulfoxide (Me2SO) decreases the onset IIF temperature, but increases PIF. Cooling rate and Me2SO concentration significantly affect IIF. The finding has significant implications in both cryopreservation and cryosurgery.

Characterization of high-performance organic dyes for dye-sensitized solar cell: a DFT/TDDFT study

Dye-sensitized solar cell (DSSC) is currently a promising technology that makes solar energy efficient and cost-effective to harness. In DSSC, metal-free dyes such as indoline-containing D149 and D205 have been proven to be potential alternatives for traditional metal organic dyes. In this work, a DFT/TDDFT characterization for D149 and D205 was carried out using different functionals, including B3LYP, MPW1K, CAM–B3LYP, and PBE0. Three different conformers for D149 and four different conformers for D205 were identified and calculated in a vacuum. The performance of different functionals on calculating the maximum absorbance of the dyes in a vacuum and five common solvents (acetonitrile, chloroform, ethanol, methanol, and THF) were examined and compared to determine the suitable computational setting for predicting properties of these two dyes. Furthermore, deprotonated D149 and D205 in solvents were also considered, and the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) were calculated, which elucidates the substitution effect on the rhodanine ring of D149 and D205 dyes on their efficiency. Finally, D149 and D205 molecules were confirmed to be firmly anchored on ZnO surface by periodic DFT calculations. These results shed light on the design of new, highly efficient metal-free dyes.

Clinical application of whole-genome low-coverage next-generation sequencing to detect and characterize balanced chromosomal translocations

Individuals carrying balanced translocations have a high risk of birth defects, recurrent spontaneous abortions and infertility. Thus, the detection and characterization of balanced translocations is important to reveal the genetic background of the carriers and to provide proper genetic counseling. Next-generation sequencing (NGS), which has great advantages over other methods such as karyotyping and fluorescence in situ hybridization (FISH), has been used to detect disease-associated breakpoints. Herein, to evaluate the application of this technology to detect balanced translocations in the clinic, we performed a parental study for prenatal cases with unbalanced translocations. Eight candidate families with potential balanced translocations were investigated using two strategies in parallel, low-coverage whole-genome sequencing (WGS) followed-up by Sanger sequencing and G-banding karyotype coupled with FISH. G-banding analysis revealed three balanced translocations, and FISH detected two cryptic submicroscopic balanced translocations. Consistently, WGS detected five balanced translocations and mapped all the breakpoints by Sanger sequencing. Analysis of the breakpoints revealed that six genes were disrupted in the four apparently healthy carriers. In summary, our result suggested low-coverage WGS can detect balanced translocations reliably and can map breakpoints precisely compared with conventional procedures. WGS may replace cytogenetic methods in the diagnosis of balanced translocation carriers in the clinic.

Systematic review with meta-analysis: development of hepatocellular carcinoma in chronic hepatitis B patients with hepatitis B surface antigen seroclearance

BACKGROUND

The seroclearance of hepatitis B surface antigen (HBsAg) in patients with chronic hepatitis B (CHB) is considered to be associated with favourable clinical outcomes. However, previous studies with inconsistent findings reported that hepatocellular carcinoma (HCC) could still develop in those patients.

AIM

To establish the proportion of HCC occurrence in CHB patients after HBsAg seroclearance, a systematic review and meta-analysis was performed.

METHODS

Databases of Medline, Web of Science and Embase were searched from inception to July 2015. The proportion of patients who developed HCC after HBsAg seroclearance was pooled by a random-effects model.

RESULTS

Twenty-eight studies were finally included, involving 34 952 patients with HBsAg seroclearance. The overall pooled proportion suggested that 2.29% (95% CI: 1.19-4.37%) CHB patients would develop HCC despite HBsAg seroclearance. In HBsAg seroclearance patients without cirrhosis and HCV co-infection, the pooled proportion of HCC development was 1.55% (95% CI: 0.92-2.61%). Moreover, patients with cirrhosis or age greater than 50 years at the time of HBsAg seroclearance were at significantly higher risk for HCC development. Nonetheless, the seroclearance of HBsAg was significantly associated with a reduced risk for HCC compared with persistently positive HBsAg (RR = 0.34, 95% CI: 0.20-0.56, P < 0.001).

CONCLUSIONS

Despite that HBsAg seroclearance can significantly reduce the risk for HCC, HCC can still develop in a proportion of CHB patient after HBsAg seroclearance. Closer attention should be paid to those patients with established cirrhosis or older age than 50 years at the time of HBsAg seroclearance.

Cardiovascular MRI with ferumoxytol

The practice of contrast-enhanced magnetic resonance angiography (CEMRA) has changed significantly in the span of a decade. Concerns regarding gadolinium (Gd)-associated nephrogenic systemic fibrosis in those with severely impaired renal function spurred developments in low-dose CEMRA and non-contrast MRA as well as efforts to seek alternative MR contrast agents. Originally developed for MR imaging use, ferumoxytol (an ultra-small superparamagnetic iron oxide nanoparticle), is currently approved by the US Food and Drug Administration for the treatment of iron deficiency anaemia in adults with renal disease. Since its clinical availability in 2009, there has been rising interest in the scientific and clinical use of ferumoxytol as an MR contrast agent. The unique physicochemical and pharmacokinetic properties of ferumoxytol, including its long intravascular half-life and high r1 relaxivity, support a spectrum of MRI applications beyond the scope of Gd-based contrast agents. Moreover, whereas Gd is not found in biological systems, iron is essential for normal metabolism, and nutritional iron deficiency poses major public health challenges worldwide. Once the carbohydrate shell of ferumoxytol is degraded, the elemental iron at its core is incorporated into the reticuloendothelial system. These considerations position ferumoxytol as a potential game changer in the field of CEMRA and MRI. In this paper, we aim to summarise our experience with the cardiovascular applications of ferumoxytol and provide a brief synopsis of ongoing investigations on ferumoxytol-enhanced MR applications.

Prediction and preliminary screening of HLA-A*0201-restricted epitope peptides of human GPC3

In response to the limited therapeutic option for hepatocellular carcinoma (HCC), immunotherapy as a promising approach points out a new direction to the cure of tumours through specific recognition and elimination of tumour cells by the immunity-enhanced autologous immunocytes of patients. Few effective tumour antigens, however, are alternative in addition to alpha fetoprotein or tumour cell lysates. Recent studies have demonstrated that glypican-3 (GPC3) is not only a promising diagnostic marker, but also ideal therapeutic target to HCC. In this study, potential HLA-A*0201 GPC3 peptides were screened with three epitope prediction software, the binding affinity of 13 predicted epitopes with high scores was determined by T2 cells binding assay and four optimal epitopes were identified. This is the first study in which the optimal HLA-A*0201 GPC3 epitopes were screened from a large number of candidates predicted by three software. The optimized HLA-A*0201 GPC3 peptides will provide new epitope candidates for HCC immunotherapy.

Systemic delivery of chTNT-3/CpG immunoconjugates for immunotherapy in murine solid tumor models

CpG oligodeoxynucleotides (CpG) potently activate the immune system by mimicking microbial DNA. Conjugation of CpG to chTNT-3, an antibody targeting the necrotic centers of tumors, enabled CpG to accumulate in tumors after systemic delivery, where it can activate the immune system in the presence of tumor antigens. CpG chemically conjugated to chTNT-3 (chTNT-3/CpG) were compared to free CpG in their ability to stimulate the immune system in vitro and reduce tumor burden in vivo. In subcutaneous Colon 26 adenocarcinoma and B16-F10 melanoma models in BALB/c and C57BL/6 mice, respectively, chTNT-3/CpG, free CpG, or several different control constructs were administered systemically. Intraperitoneal injections of chTNT-3/CpG delayed tumor growth and improved survival and were comparable to intratumorally administered CpG. Compared to saline-treated mice, chTNT-3/CpG-treated mice had smaller average tumor volumes by as much as 72% in Colon 26-bearing mice and 79% in B16-bearing mice. Systemically delivered free CpG and CpG conjugated to an isotype control antibody did not reduce tumor burden or improve survival. In this study, chTNT-3/CpG retained immunostimulatory activity of the CpG moiety and enabled delivery to tumors. Because systemically administered CpG rapidly clear the body and do not accumulate into tumors, chTNT-3/CpG provide a solution to the limitations observed in preclinical and clinical trials.

A comparison of telbivudine and entecavir in the treatment of hepatitis B e antigen-positive patients: a prospective cohort study in China

There are few studies directly comparing the efficacy and safety of telbivudine and entecavir. The present prospective cohort study aimed to evaluate the long-term efficacy and safety of these compounds in 196 hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B for a median follow-up period of 172 weeks; 97 were treated with telbivudine and 99 were treated with entecavir. Patients showing suboptimal responses could also take adefovir at 24-48 weeks and all patients with viral breakthrough were started on adefovir. The 240-week cumulative proportions of patients showing undetectable hepatitis B DNA levels and serum alanine transaminase (ALT) normalization were similar in the two study groups. Viral breakthrough developed in 14% of the telbivudine group and in 2% of the entecavir group (p 0.002). Interestingly, the cumulative proportions of patients treated with entecavir and telbivudine showing HBeAg seroconversion were 12% versus 21% at 48 weeks (p 0.041), 15% versus 38% at 96 weeks (p 0.001), 24% versus 50% at 144 weeks (p 0.001), 33% versus 53% at 192 weeks (p 0.004) and 36% versus 53% at 240 weeks (p 0.005), respectively. Patients treated with telbivudine were therefore significantly more likely to show HBeAg seroconversion than those receiving entecavir and similar results were observed in study sub-groups matched for age, serum ALT, and HBV DNA levels. A safety analysis identified no differences between grade 3/4 creatine kinase elevations in the study groups and only telbivudine was associated with improved kidney function.

Towards rational catalyst design: a general optimization framework

Rational catalyst design is one of the most fundamental goals in heterogeneous catalysis. Herein, we briefly review our previous design work, and then introduce a general optimization framework, which converts catalyst design into an optimization problem. Furthermore, an example is given using the gradient ascent method to show how this framework can be used for rational catalyst design. This framework may be applied to other design schemes.