Conformational and static properties of tagged chains in solvents: effect of chain connectivity in solvent molecules.

Polymer chains immersed in different solvent molecules exhibit diverse properties due to multiple spatiotemporal scales and complex interactions. Using molecular dynamics simulations, we study the conformational and static properties of tagged chains in different solvent molecules. Two types of solvent molecules were examined: one type consisted of chain molecules connected by bonds, while the other type consisted of individual bead molecules without any bonds. The only difference between the two solvent molecules lies in the chain connectivity. Our results show a compression of the tagged chains with the addition of bead or chain molecules. Chain molecule confinement induces a stronger compression compared to bead molecule confinement. In chain solvent molecules, the tagged chain's radius of gyration reached a minimum at a monomer volume fraction of ∼0.3. Notably, the probability distributions of chain size remain unchanged at different solvent densities, irrespective of whether the solvent consists of beads or polymers. Furthermore, as solvent density increases, a crossover from a unimodal to a bimodal distribution of bond angles is observed, indicating the presence of both compressed and expanded regions within the chain. The effective monomer-solvent interaction is obtained by calculating the partial radial distribution function and the potential of the mean force. In chain solvents, the correlation hole effect results in a reduced number of nearest neighbors around tagged monomers compared to bead solvents. The calculation of pore size distribution reveals that the solvent nonhomogeneity induced by chain connectivity leads to a broader distribution of pore sizes and larger pore dimensions at low volume fractions. These findings provide a deeper understanding of the conformational behavior of polymer chains in different solvent environments.

An environmentally insensitive fluorescent probe for G4 DNA detection: Design, synthesis, and mechanism studies.

G4 DNA structure highly localized to functionally important sites within the human genome, has been identified as a biomarker for regulation of multiple biological processes. Identification G4-responsive fluorescence probes has broad application prospects for addressing G4 biological functions, as well as developing of new families of anticancer drugs. However, some currently designed G4 DNA probes may suffer from serious solvent-dependent effect, and cause unspecific fluorescence that masks the specific signal from G4 DNA. Herein, with a bulky imidazole-cored molecular rotor fusing in D-A building block of carbazole-pyridinium, we constructed a new probe ACPS. This new probe with desirable environmentally insensitive property exhibited a "fluorescence-off" state in various polarity solvents. In the presence of G4 DNA, the intra-molecular rotations would be restricted, triggering intense fluorescence enhancement. Especially, probe ACPS bound to G4 DNA structures with superior selectivity, exhibiting much weaker fluorescence response in the presence of non-G4 DNA structures. This probe was also able to realize fluorescence visualization in cell imaging. Collectively, the probe design strategy eliminates the background fluorescence caused by uncontrollable environmental polarity change, thereby achieving high-fidelity sensing G4 DNA structures in complicated systems.

Selective c-MYC G4 DNA recognition based on a fluorescent light-up probe with disaggregation-induced emission characteristics.

The c-MYC promoter is well-known as an important oncogene, the overexpression of which leads to ∼80% of all solid tumors. The four-stranded G4 present in the c-MYC promoter has been shown to play a pivotal role in the regulation of c-MYC transcription. Accordingly, strategies employed for c-MYC G4 DNA sensing have implications for the detection of many human pathologies. However, achieving specificity toward c-MYC G4 over other structurally similar G4s is a challenging task. Here, a supramolecular strategy that relies on the recognition-driven disaggregation of a novel BODIPY probe is outlined. The synthesized probe remained almost non-fluorescent in aqueous media in the aggregation state. Of all the tested G4 and non-G4 DNAs, only c-MYC triggered probe disaggregation and induced a significant increase in fluorescence intensity. The binding details discussed here suggest the basis for the recognition of a particular G4 structure, thus opening up a new way for the design and development of sequence-selective supramolecular G4 probes with desired properties.

Design, synthesis and mechanistic studies of a TICT based fluorogenic probe for lighting up protein HSA.

Human serum albumin (HSA) in blood serves as an important biomarker for clinical diagnosis, and fluorescence sensing method has attracted extensive attention. In this work, a small organic molecule probe, YS8, involving twisted intramolecular charge transfer (TICT) characteristic, was designed and investigated to detect HSA. YS8 kept silent state in fluorescence under physiological conditions, but the encapsulation of YS8 in the hydrophobic subdomain IB region of HSA inhibited the TICT state and produced a clear light-up fluorescent signal. Especially, YS8 was demonstrated to be an efficient fluorogenic probe to discriminate HSA from other proteins including the bovine serum albumin (BSA). Moreover, YS8/HSA complex could be applied in fluorescence imaging in living cells and is also useful in the study of artificial fluorescent protein (AFP).

Amphiphilic BODIPY-based nanoparticles as "light-up" fluorescent probe for PAEs detection by an aggregation/disaggregation approach.

Phthalic acid eaters (PAEs) play the role of plasticizer and have been widely used in the industrial and plastic production process. But due to not chemically bound in the polymeric matrix, PAEs can be easily released directly and/or indirectly into the environment, and pose a threat the ecosystem and human health. Small-molecule self-assembled nanoparticles have drawn more and more attention due to advantages of precise molecular structure, biocompatibility, great diversity, and tunability in optical properties and functionalities. Here we report the use of disaggregation-induced emission (DIE) based supramolecular assembly to design organic nanoprobe for detection PAEs. In the water solution, the designed small organic fluorophore AJ-1 was aggregated via noncovalent forces to form fluorescence off nanoparticles, but in the presence of PAEs, they disaggregated and produced a clear light-up fluorescent signal. The detection of PAEs with selectivity, sensitivity and rapid response were further achieved. The experiment of recovery of PAEs in real-water sample illustrated the practicability of probe AJ-1 in real-world applications. Besides, cellular uptake assay suggested that AJ-1 could pass through membrane and gather in the cytoplasm.

Microenvironment-Sensitive Fluorescent Ligand Binds Ascaris Telomere Antiparallel G-Quadruplex DNA with Blue-Shift and Enhanced Emission.

The development of small molecules that can selectively target G-quadruplex (G4) DNAs has drawn considerable attention due to their unique physiological and pathological functions. However, only a few molecules have been found to selectively bind a particular G4 DNA structure. We have developed a fluorescence ligand Q1, a molecular scaffold with a carbazole-pyridine core bridged by a phenylboronic acid side chain, that acts as a selective ascaris telomere antiparallel G4 DNA ASC20 ligand with about 18 nm blue-shifted and enhanced fluorescence intensity. Photophysical properties revealed that Q1 was sensitive to the microenvironment and gave the best selectivity to ASC20 with an equilibrium binding constant Ka =6.04×105  M-1 . Time-resolved fluorescence studies also demonstrated that Q1 showed a longer fluorescence lifetime in the presence of ASC20. The binding characteristics of Q1 with ASC20 were shown in detail in a fluorescent intercalator displacement (FID) assay, a 2-Ap titration experiment and by molecular docking. Ligand Q1 could adopt an appropriate pose at terminal G-quartets of ASC20 through multiple interactions including π-π stacking between aromatic rings; this led to strong fluorescence enhancement. In addition, a co-staining image showed that Q1 is mainly distributed in the cytoplasm. Accordingly, this work provides insights for the development of ligands that selectively targeting a specific G4 DNA structure.

Expression of Ki-67, Cyclin D1, P53, and P16 in patients with oral leukoplakia and leukoplakia cancerization with spicy diet in Chengdu / 华西口腔医学杂志

OBJECTIVES@#To investigate the expression of Ki-67, Cyclin D1, P53, and P16 in patients with oral leukoplakia (OLK) and OLK cancerization who have aspicy diet in Chengdu.@*METHODS@#Thirtypatients with OLK andspicy diet and 15 patients with OLK without spicy diet in Chengdu were divided into three groups: hyperplastic OLK (OLK-), OLK with mild to moderate dysplasia (OLK+), and severe dysplastic  OLK or oral squamous cell carcinoma (OSCC) transforming from OLK (OLK++/OSCC). The expression of Ki-67, Cyclin D1, P53, and P16 were detected by immunohistochemistry and statistically analyzed.@*RESULTS@#The expression of Ki-67 and P53 in patients with or without spicy diet in the OLK+and OLK++/OSCC groups were stronger than that of the OLK- group (@*CONCLUSIONS@#Spicy diet did not have an influence on the expression of Ki-67, Cyclin D1, P53, and P16 in patients with OLK and OSCC. The expression of Ki-67, Cyclin D1, and P53 increased with the development of OLK, whereas P16 showed opposite expression trend.

Improvement program on pretreatment of acid decalcified tissue in hematoxylin-eosin staining / 华西口腔医学杂志

OBJECTIVE@#To explore the treatment conditions of acid decalcified specimens and improve the poor quality of sections and unclear structure of hematoxylin-eosin (HE) staining caused by the change in pH in tooth and hard tissue after acid decalcification.@*METHODS@#A total of 20 cases of oral pathological specimens that contain hard tissues were decalcified and treated with routine treatment, concentrated ammonia water immersion treatment, and saturated lithium carbonate solution immersion treatment. The quality and HE staining effects of hard tissue sections treated with different methods were compared.@*RESULTS@#Compared with routine treatment, lithium carbonate saturated solution treatment showed complete sections. Hematoxylin is strongly stained, the nucleus is clear, and the cytoplasm is bright.@*CONCLUSIONS@#Soaking acid decalcified specimens in lithium carbonate saturated solution before embedding in dehydration can neutralize the acidic environment of the tissue. The quality of sections and HE staining effect are improved and are suitable for the pretreatment of acid decalcified tissue samples of oral pathology.

Development of a carbazole-based fluorescence probe for G-quadruplex DNA: The importance of side-group effect on binding specificity.

G-quadruplex DNAs are highly prevalent in the human genome and involved in many important biological processes. However, many aspects of their biological mechanism and significance still need to be elucidated. Therefore, the development of fluorescent probes for G-quadruplex detection is important for the basic research. We report here on the development of small molecular dyes designed on the basis of carbazole scaffold by introducing styrene-like substituents at its 9-position, for the purpose of G-quadruplex recognition. Results revealed that the side group on the carbazole scaffold was very important for their ability to selectively recognize G-quadruplex DNA structures. 1a with the pyridine side group displayed excellent fluorescence signal turn-on property for the specific discrimination of G-quadruplex DNAs against other nucleic acids. The characteristics of 1a were further investigated with UV-vis spectrophotometry, fluorescence, circular dichroism, FID assay and molecular docking to validate the selectivity, sensitivity and detailed binding mode toward G-quadruplex DNAs.

Receptor for advanced glycation end products upregulates MUC5AC expression and promotes mucus overproduction in mice with toluene diisocyanate-induced asthma / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the role of the receptor for advanced glycation end products (RAGE) in regulating the expression of MUC5AC and mucus production in a mouse model of toluene diisocyanate (TDI)?induced asthma.</p><p><b>METHODS</b>BALB/c mice were randomly divided into control group, vehicle (AOO) group, TDI?induced asthma group and RAGE inhibitor (FPS?ZM1) group. PAS staining, Western blotting, and immunohistochemistry were used to analyze the changes in mucus production and MUC5AC expression in the airway of the mice, and the expression of p?ERK was detected with Western blotting. In vitro cultured human bronchial epithelial cell line 16HBE was transfected with lentiviral vector carrying short hairpin RNA targeting RAGE (shRNA?RAGE) and subsequently challenged with a TDI?human serum albumin (TDI-HSA) conjugate, and the changes in cellular MUC5AC mRNA expression as detected using RT-PCR; the protein expressions of ERK and p?ERK in the cells were examined with Western blotting. The effect of ERK inhibitor U0126 pretreatment on MUC5AC mRNA expression was also analyzed in the cells.</p><p><b>RESULTS</b>Compared with the control mice, TDI-induced asthmatic mice showed significantly higher rates of PAS positivity and increased MUC5AC and p?ERK expressions in the airway (P<0.05). Treatment with FPS?ZM1 significantly decreased PAS positivity and lowered MUC5AC and p?ERK expressions in the airway of the asthmatic mice (P<0.05). Exposure of 16HBE cells to TDI?HSA caused a significant increase in MUC5AC mRNA expression and p?ERK protein expression (P<0.05), while RAGE knockdown obviously suppressed TDI?HSA-induced upregulation of p-ERK and MUC5AC mRNA (P<0.05). Treatment with the ERK inhibitor U0126 also lowered TDI?HSA?induced up?regulation of MUC5AC mRNA in the cells (P<0.05).</p><p><b>CONCLUSION</b>RAGE signaling induces MUC5AC expression via extracellular signal-regulated kinase pathway to promote mucus overproduction in mice with TDI-induced asthma.</p>

Stenting of the Portal Vein Combined with Different Numbers of Iodine-125 Seed Strands: Dosimetric Analyses / 中华医学杂志(英文版)

<p><b>Background:</b>Portal-vein stent combined with one iodine-125 (I) seed strand has become a new treatment for portal vein tumor thrombosis. However, dosimetric aspects of this irradiation stent have not been reported. Therefore, we aimed to undertake dosimetric analyses comparing portal-vein stents combined with different numbers ofI seed strands.</p><p><b>Methods:</b>A water cylinder was created by a treatment-planning system to simulate a portal-vein stent. The stent was combined with one, two, or threeI seed strands (Groups I, II, and III, respectively). At different prescribed doses (PDs),I seeds of identical activities were loaded on Groups I-III. Conformation number (CN), external volume index, and homogeneity index were calculated. Linear regression analyses were used to evaluate the obtained data.</p><p><b>Results:</b>For identicalI seed activity, when theI seed strand increased from one chain to two, D(dose delivered to 90% of the target volume) increased by ≥184%; when it increased from two chains to three, Dincreased by ≥63%. When the PD was 105 Gy andI seed strands increased from one chain to two, V(percentage of the target volume receiving ≥90% of the PD) increased by 158-249%; when it increased from two chains to three, Vincreased by 7-175%. CN was correlated positively withI seed activity (B = 0.479, P < 0.001) and number ofI seed strands (B = 0.201, P < 0.001) and was independent of PD (B = -0.002, P = 0.078).</p><p><b>Conclusions:</b>A portal-vein stent combined with a singleI seed strand could not meet dosimetry requirements. For a stent combined with twoI seed strands, when the PD was 105 Gy and seed activity was 0.7 mCi, the dose distribution could satisfy dosimetry requirements. For a stent combined with threeI seed strands, if the PD was 105, 125, or 145 Gy, the recommended seed activities were 0.5, 0.5, and 0.6 mCi, respectively.</p>

Dosimetric Study of Biliary Stent Loaded with RadioactiveI Seeds / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>A novel radioactive 125I seed-loaded biliary stent has been used for patients with malignant biliary obstruction. However, the dosimetric characteristics of the stents remain unclear. Therefore, we aimed to describe the dosimetry of the stents of different lengths - with different number as well as activities of 125I seeds.</p><p><b>METHODS</b>The radiation dosimetry of three representative radioactive stent models was evaluated using a treatment planning system (TPS), thermoluminescent dosimeter (TLD) measurements, and Monte Carlo (MC) simulations. In the process of TPS calculation and TLD measurement, two different water-equivalent phantoms were designed to obtain cumulative radial dose distribution. Calibration procedures using TLD in the designed phantom were also conducted. MC simulations were performed using the Monte Carlo N-Particle eXtended version 2.5 general purpose code to calculate the radioactive stent's three-dimensional dose rate distribution in liquid water. Analysis of covariance was used to examine the factors influencing radial dose distribution of the radioactive stent.</p><p><b>RESULTS</b>The maximum reduction in cumulative radial dose was 26% when the seed activity changed from 0.5 mCi to 0.4 mCi for the same length of radioactive stents. The TLD's dose response in the range of 0-10 mGy irradiation by 137Cs γ-ray was linear: y = 182225x - 6651.9 (R2=0.99152; y is the irradiation dose in mGy, x is the TLDs' reading in nC). When TLDs were irradiated by different energy radiation sources to a dose of 1 mGy, reading of TLDs was different. Doses at a distance of 0.1 cm from the three stents' surface simulated by MC were 79, 93, and 97 Gy.</p><p><b>CONCLUSIONS</b>TPS calculation, TLD measurement, and MC simulation were performed and were found to be in good agreement. Although the whole experiment was conducted in water-equivalent phantom, data in our evaluation may provide a theoretical basis for dosimetry for the clinical application.</p>

High fractional exhaled nitric oxide may predict response to inhaled corticosteroid therapy in patients with subacute cough / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate fractional exhaled nitric oxide (FENO) level in patients with subacute cough and its value in predicting the patients' response to inhaled corticosteroids (ICS) treatment.</p><p><b>METHODS</b>A total of 100 patients with persistent cough lasting more than 3 weeks were enrolled, including 52 patients with subacute cough and 48 with chronic cough. FENO, spirometry, and responses to ICS therapy of the patients were evaluated.</p><p><b>RESULTS</b>The recruited patients had a median (inter-quartile ranges) FENO level of 19 ppb (12-30 ppb). Patients with chronic cough had a significantly higher median FENO level than those with subacute cough (20.5 vs 16 ppb; Z=-2.245, P=0.025). A FENO level ≥25 ppb was recorded in 15 (28.8%) patients with subacute cough, as compared with 20 (41.6%) in patients with chronic cough (χ(2)=1.801, P=0.179). With a FENO ≥25 ppb as the critical value to justify ICS treatment, 15 patients with subacute cough received ICS and 14 (93.3%) of them showed obvious relief of cough after 2 weeks of therapy, a response rate similar to that of 85.0% (17/20) in patients with chronic cough receiving the treatment (χ(2)=0.588, P=0.443). In patients with subacute cough, those with cough variant asthma (CVA) or eosinophilic bronchitis (EB) had a significantly higher median FENO level than those with postinfectious cough [(16 (11-31) ppb vs 11 (8-19) ppb, P<0.01]. In the etiological analysis, CVA or EB was identified in 23 (44.2%) of the patients with subacute cough, as compared 21 (43.8%) in patients with chronic cough (χ(2)=0.002, P=0.961).</p><p><b>CONCLUSION</b>FENO may be an important indicator for etiological diagnosis of subacute cough and for predicting the response to ICS treatment.</p>

Expression of neuraminidase gene of influenza virus H1N1 in baculovirus-expression system / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To construct the recombinant baculovirus with NA gene of Influenza H1N1 virus.</p><p><b>METHODS</b>Full-length NA gene of Influenza virus H1N1 (A/PR/8/34) was amplified by PCR and inserted into pFastBacdual vector to construct the recombinant baculovirus transfer vector pFBD-NA. Recombinant shuttle vectors rBacmid-NA was then obtained after transforming DH10B competent cells containing bacmid plasmids. After transfecting into sf9 cells, recombinant baculovirus rBac-NA was obtained. The rBac-NA genome was extracted and identified by PCR. NA protein expressed by recombinant baculovirus-infected sf9 cells was determined by IFA, Western Bolt and ELISA.</p><p><b>RESULTS</b>PCR results proved that recombinant shuttle vectors rBacmid-NA was successfully constructed. NA protein was detected by IFA and showed strong specific green fluorescence on the surface of infected cells. NA protein was recognized by two polyclonal antibodies specific for NA in Western Blot. ELISA showed specific reaction of recombinant NA protein with mouse polyclonal antibody against influenza virus (PR8), indicating high antigenicity.</p><p><b>CONCLUSION</b>Recombinant baculovirus rBac-NA that expresse NA protein of influenza virus was successfully constructed. This work provides a basis for further study on NA protein function and novel influenza vaccine development.</p>

Enzyme-linked immunospot test detected specific cellular immune response induced by human bocavirus VP2 virus-like particles / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To discuss the enzyme linked immune spot test (ELISPOT) detected the cellular immune response induced by human Bocavirus (HBoV) VP2 virus-like particles (VLPs).</p><p><b>METHODS</b>After immunized by HBoV VP2 VLPs, the specific cellular immune response in mice were detected by ELISPOT assay, observe the ELISPOT results at the conditions of different polypeptide stimulate, different cell culture time, different cell concentration and different specific stimulus peptide concentration, then screening the right ELISPOT experimental conditions and establish the ELISPOT method.</p><p><b>RESULTS</b>The spots induced by HBoV1 VLPs immunized mice spleen lymphocytes stimulate with polypeptide P3 (GYIPIENEL) and P5 (LYQMPFFLL)were 233 spots/10(6) cells and 157 spots/10(6) cells,spots induced by HBoV2 VLPs immunized mice spleen lymphocytes stimulate with polypeptide P8 (GYIPVIHEL) were 113 spots/10(6) cells; 24 hours is the best time for culture, at this time HBoV1 and HBoV2 groups specificity secretion IFN-gamma ratio were 232 spots/10(6) cells and 119/10(6) cells; Best concentration of mice spleen lymphocyte is 5 x 10(5), right now HBoV1 and HBoV2 group specificity secretion IFN-gamma ratio were 232 spots/10(6) cells and 108/10(6) cells; Best concentration of polypeptides is 10 microg/ml, HBoV1 and HBoV2 group specificity secretion IFN -gamma ratio were 233 spots/10(6) cells and 96/10(6) cells.</p><p><b>CONCLUSIONS</b>HBoV1 and HBoV2 specificT-cell epitope in BABL/c mice were P3, P5 (HBoV1) and P8 (HBoV2). The best experiment condition were: cell cultivated for 24 h, cells concentration for 5 x 10(5) cells/well, stimulating polyperides concentration for 10 microg/ml, it can use to study the cellular immune induced by HBoV in mice.</p>

Establishment of mammalian cell lines for constitutive expression of influenza virus matrix protein 2 / 病毒学报

To establish a mammalian cell line for stable expression of the matrix protein 2 (M2) of influenza virus type A. M2 gene was amplified by PCR from the influenza virus strain A/PR/8/34. The PCR product was cloned into eukaryotic expression vector pcDNA5/FRT. After identification with restriction enzyme digestion, the plasmid was co-transfected with plasmid pOG44 which expressed Flp in Flp-In-CHO cells. The target gene was integrated into chromosome of CHO cells by homologous recombination in vivo. Recombinant CHO-M2 cell lines were selected for hygromycin B resistance. A total of 15 recombinant cell strains with high expression of M2 protein were screened by hygromycin, and the expression of M2 protein was determined by IFA and Western blot. After subculturing for 10 passages, the presence of M2 gene in the CHO-M2 cells was confirmed by PCR, and the expression of M2 protein were proved by IFA and Western blot. We successfully constructed a mammalian cell line which stably expressed M2 protein of influenza virus type A. The cell line will be useful for studies on function of M2 protein and provide tools for novel influenza virus vaccine development.

Construction of recombinant baculovirus co-expressing M1 and HA of influenza A virus / 病毒学报

The M1 and HA genes of H1N1 influenza virus were amplified and then cloned into the pFastBac dual donor plasmid. The recombinant pFastBac Dual-M1-HA was identified by restriction enzyme digestion. After the pFastBacdual-M1-HA was transformed into the baculovirus shuttle plasmid (bacmid) in DH10Bac competent cells, the colonies were identified by antibiotics and blue-white selection. The rBac-mid-M1-HA was verified by PCR and transfected into S f9 cells to produce recombinant baculovirus (rBac-M1-HA). Gene insertion of rBac-M1-HA was verified and the expression of M1 and HA genes was analyzed by IFA and Western-blot, demonstrating M1 and HA were co-expressed successfully. This study provides the foundation for researching the formation mechanism of influenza VLP and developing new influenza vaccines.

Subcloning of M1 gene fragment of H5N1 influenza virus and its expression in Escherichia coli / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To generate the Escherichia col vector expressing human H5N1 influenza virus M1 protein. To provide useful tools for detection of human H5N1 influenza virus and study on biological function of M1 protein.</p><p><b>METHODS</b>M1 gene fragment was amplified by PCR using the influenza virus gene segment 7 as template, and was subcloned into pQE80-L vector. The recombinant plasmid pQE80-L/M1 was transformed into Escherichia coil BL21 (DE3) strain. The expression of M1 was induced by isopropy-beta3-D-thiogalactopyranoside. We purified the recombinant M1 protein with polyhistidine tag with Ni2+ affinity chromatography. Mouse were immunized with the purified M1 protein for preparing antibodies against M1.</p><p><b>RESULTS</b>The recombinant Ml protein was recognized by antiserum against H5N1 subtype influenza virus, elicit specific antibody in immunized animals.</p><p><b>CONCLUSION</b>These confirmed that we successfully constructed the Escherichia coli vector expressing human H5N1 influenza virus M1 protein.</p>