A candidate multi-epitope vaccine against porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae induces robust humoral and cellular response in mice

Porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae (M. hyopneumoniae, Mhp) are two of the most common pathogens involved in the porcine respiratory disease complex (PRDC) resulting in significant economic losses worldwide. Vaccination is the most effective approach to disease prevention. Since PRRSV and Mhp co-infections are very common, an efficient dual vaccine against these pathogens is required for the global swine industry. Compared with traditional vaccines, multi-epitope vaccines have several advantages, they are comparatively easy to produce and construct, are chemically stable, and do not have an infectious potential. In this study, to develop a safe and effective vaccine, B cell and T cell epitopes of PRRSV-GP5, PRRSV-M, Mhp-P46, and Mhp-P65 protein had been screened to construct a recombinant epitope protein rEP-PM that has good hydrophilicity, strong antigenicity, and high surface accessibility, and each epitope is independent and complete. After immunization in mice, rEP-PM could induce the production of high levels of antibodies, and it had good immunoreactivity with anti-rEP-PM, anti-PRRSV, and anti-Mhp antibodies. The anti-rEP-PM antibody specifically recognizes proteins from PRRSV and Mhp. Moreover, rEP-PM induced a Th1-dominant cellular immune response in mice. Our results showed that the rEP-PM protein could be a potential candidate for the development of a safe and effective multi-epitope peptide combined vaccine to control PRRSV and Mhp infections.     

Internalization of titanium dioxide nanoparticles by glial cells is given at short times and is mainly mediated by actin reorganization-dependent endocytosis

Many nanoparticles (NPs) have toxic effects on multiple cell lines. This toxicity is assumed to be related to their accumulation within cells. However, the process of internalization of NPs has not yet been fully characterized. In this study, the cellular uptake, accumulation, and localization of titanium dioxide nanoparticles (TiO₂ NPs) in rat (C6) and human (U373) glial cells were analyzed using time-lapse microscopy (TLM) and transmission electron microscopy (TEM). Cytochalasin D (Cyt-D) was used to evaluate whether the internalization process depends of actin reorganization. To determine whether the NP uptake is mediated by phagocytosis or macropinocytosis, nitroblue tetrazolium (NBT) reduction was measured and the 5-(N-ethyl-N-isopropyl)-amiloride was used. Expression of proteins involved with endocytosis and exocytosis such as caveolin-1 (Cav-1) and cysteine string proteins (CSPs) was also determined using flow cytometry.TiO₂ NPs were taken up by both cell types, were bound to cellular membranes and were internalized at very short times after exposure (C6, 30 min; U373, 2 h). During the uptake process, the formation of pseudopodia and intracellular vesicles was observed, indicating that this process was mediated by endocytosis. No specific localization of TiO₂ NPs into particular organelles was found: in contrast, they were primarily localized into large vesicles in the cytoplasm. Internalization of TiO₂ NPs was strongly inhibited by Cyt-D in both cells and by amiloride in U373 cells; besides, the observed endocytosis was not associated with NBT reduction in either cell type, indicating that macropinocytosis is the main process of internalization in U373 cells. In addition, increases in the expression of Cav-1 protein and CSPs were observed.In conclusion, glial cells are able to internalize TiO₂ NPs by a constitutive endocytic mechanism which may be associated with their strong cytotoxic effect in these cells; therefore, TiO₂ NPs internalization and their accumulation in brain cells could be dangerous to human health.     

Purification and characterization of the carbonic anhydrase enzyme from Black Sea trout (Salmo trutta Labrax Coruhensis) kidney and inhibition effects of some metal ions on enzyme activity

In this study, the carbonic anhydrase (CA) enzyme was purified from Black Sea trout (Salmo trutta Labrax Coruhensis) kidney with a specific activity of 603.77 EU/mg and a yield of 35.5% using Sepharose-4B-l-tyrosine- sulphanilamide affinity column chromatography. For determining the enzyme purity and subunit molecular mass, sodiumdodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was performed and single band was observed. The molecular mass of subunit was found approximately 29.71 kDa. The optimum temperature, activation energy (E_a), activation enthalpy (ΔH) and Q₁₀ values were obtained from Arrhenius plot. K_m and V_max values for p-nitrophenyl acetate of the purified enzyme were calculated from Lineweaver-Burk graphs. In addition, the inhibitory effects of different heavy metal ions (Fe²⁺, Pb²⁺, Co²⁺, Ag⁺ and Cu²⁺) on Black Sea trout kidney tissue CA enzyme activities were investigated by using esterase method under in vitro conditions. The heavy metal concentrations inhibiting 50% of enzyme activity (IC₅₀) were obtained. Finally K_i values and inhibition types were calculated from Lineweaver-Burk graphs.     

Aflibercept in Combination With FOLFIRI as First-line Chemotherapy in Patients With Metastatic Colorectal Cancer (mCRC): A Phase II Study (FFCD 1302)

BackgroundFOLFIRI (irinotecan, 5-fluorouracil, and leucovorin) + aflibercept improves median overall survival (OS) and progression-free survival (PFS) in patients with previously treated metastatic colorectal cancer (mCRC). Our aim was to investigate efficacy and tolerability of this combination in the first line.Patients and MethodsPatients with untreated documented mCRC received aflibercept plus FOLFIRI every 14 days until progression or unacceptable toxicity in an open, phase II single-arm, multicenter trial. The primary endpoint was the 6-month PFS rate. Secondary endpoints were OS and tolerability. A 2-step Simon design was used with H₀: 55% and H₁= 75%. Data were analyzed in intention to treat.ResultsForty-one patients were included, and 40 were analyzed (1 consent withdrawal) in 9 French centers between October 2014 and February 2017. The median age was 65 years (range, 46-81 years), 55% had ≥ 2 metastatic sites, and 50% and 15% had RAS and BRAF mutations, respectively. Twenty-two (54.5%; 95% confidence interval, 38.9%-68.5%) patients were alive and non-progressive at 6 months. FOLFIRI + aflibercept was considered ineffective, resulting in the cessation of inclusions. The median follow-up was 34 months. The overall response rate was 55%, and the disease control rate was 80%. The median duration of treatment was 5.3 months; the median PFS and OS were 8.2 and 18.6 months, respectively. Grade 3 to 4 adverse events were mainly gastrointestinal (47.5%) and vascular (32.5%). Of the patients, 87.5% had at least 1 dose modification.ConclusionAlthough the primary objective was not met, first-line FOLFIRI + aflibercept for mCRC leads to median PFS and OS close to those reported with classical doublet and targeted agents, but with significant toxicities needing dose reduction.     

亚硒酸钠诱导白内障的机理研究

在pH8.0-8.5条件下,谷胱甘肽、氧或过氧化氢过量时,微量的10~(-4)mol·L~(-1)亚硒酸钠能使鲁米诺产生稳定的化学发光。发光强度依赖于酸度、谷胱甘肽浓度、氧及过氧化氢的浓度。超氧化物歧化酶(SOD)对鲁米诺发光有明显的抑制作用。SeO_3~(2-)在眼内催化产生活性氧可能是产生白内障的原因。