[Efficacy analysis of hepatic arterial infusion chemotherapy combined with targeted and immune therapy followed by 125I seeds implantation in the treatment of hepatocellular carcinoma with portal vain tumor thrombus]

Objective: To investigate the safety and efficacy of Hepatic Arterial Infusion Chemotherapy(HAIC) combined with targeted and immune therapy followed by 125I seeds implantation in portal vain tumor thrombus (PVTT) in the treatment of hepatocellular carcinoma(HCC) with PVTT. Methods: A retrospective study was performed on the clinical data of 21 patients [ (11 men, 10 women) aged 34-73 (52.6±13.7) years] with HCC with PVTT in The First Affiliated Hospital of Zhengzhou University from October 2020 to October 2022, all of them were treated with HAIC plus targeted and immune therapy,and 125I seeds implanted into PVTT. The patients were followed up to January 2023, the efficacy was evaluated according to the modified version of the solid tumor efficacy evaluation criteria (mRECIST). The progression-free survival (PFS) rate, overall survival(OS) rate and portal tumor thrombus control rate at 3, 6, 12 and 18 months after treatment were recorded, and PFS and OS time were followed up. The changes of liver function, AFP, coagulation function and adverse events were observed. Results: Each patient received 2 to 7 (mean: 3.3±1.2) cycles of HAIC. 10-37 seeds (mean:16.6±6.7) were implanted per patients. The median follow-up time was 15 (range from 5 to 25) months.During the follow-up time, 15 patients showed progression and 6 patients died, and the PFS rates at 3, 6, 12, and 18 months after treatment were 90.5%, 71.4%, 42.9%, and 23.8%, respectively, and at 3, 6, 12, and 18-month OS rates were 100%, 100%, 81.0%, and 61.9%, respectively.The PVTT control rates at 3, 6, and 12 months were 90.5%, 90.5%, and 62.5%, respectively. Overall efficacy evaluation of CR rate 0, PR rate 47.6% (10/21), SD rate 38.1% (8/21), and PD rate 14.3% (3/21). The total incidence of treatment-related adverse events was 100%.Grade 3 treatment related adverse events were observed for 4 cases, the rest wereⅠtoⅡadverse events. Right upper abdominal pain, fever and hemorrhage in liver capsule related to the procedures were observed in 11(52.4%), 5(23.8%) and 3(14.3) patients, respectively. Conclusion: HAIC combined with targeted and immune therapy followed by 125I seeds implantation in PVTT is a safe and efficacy therapy for HCC with PVTT.

[Bibliometric analysis on research hotspots on HIV post-exposure prophylaxis related articles in the world, 2000-2017]

Objective: To analyze and reveal the distribution, research hotspots and study trend of worldwide published articles correlated with HIV/AIDS post-exposure prophylaxis (PEP), and provide information for related studies in China. Methods: CiteSpace software 5.1 was used to visualize all related papers in the web of science database published during 2000-2017. Results: The average growth rate of international PEP-related papers was 10.78%,and number of published papers in 2016 was highest (n=34), relevant research hotspots have shifted from the prevention of occupational HIV exposure to the prevention of non-occupational HIV exposure in group at high risk, such as MSM, in recent years. Clustering analysis classified research hotspots into three categories, including risk reduction through enhanced intervention, current status of global HIV PEP and German-Austrian Recommendation. Conclusions: Non-occupational HIV PEP in groups at high-risk, especially MSM, has received increasing attention in recent years, the research of PEP mainly focus on improving the awareness and use of PEP in MSM and compliance in the course of medication. In the context of severe HIV epidemic in MSM without effective control in China, PEP should be strengthened to assess and explore the risk of HIV infection in MSM to provide reference for medical personnel and related departments to implement HIV non-occupation exposure blockade and formulate PEP medication.

O-GlcNAcylation regulates breast cancer metastasis via SIRT1 modulation of FOXM1 pathway

Tumors utilize aerobic glycolysis to support growth and invasion. However, the molecular mechanisms that link metabolism with invasion are not well understood. The nutrient sensor O-linked-β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) modifies intracellular proteins with N-acetylglucosamine. Cancers display elevated O-GlcNAcylation and suppression of O-GlcNAcylation inhibits cancer invasion and metastasis. Here, we show that the regulation of cancer invasion by OGT is dependent on the NAD⁺-dependent deacetylase SIRT1. Reducing O-GlcNAcylation elevates SIRT1 levels and activity in an AMPK-dependent manner. Reduced O-GlcNAcylation in cancer cells leads to SIRT1-mediated proteasomal degradation of oncogenic transcription factor FOXM1 in a MEK/ERK-dependent manner. SIRT1 is critical for OGT-mediated regulation of FOXM1 ubiquitination and reducing SIRT1 activity reverses OGT-mediated regulation of FOXM1. Moreover, we show that SIRT1 levels are required for OGT-mediated regulation of invasion and metastasis in breast cancer cells. Thus, O-GlcNAcylation is a central component linking metabolism to invasion and metastasis via a SIRT1/ /FOXM1 axis.

Highly reflective liquid mirrors: exploring the effects of localized surface plasmon resonance and the arrangement of nanoparticles on metal liquid-like films

In this paper, we describe a high-reflectance liquid mirror prepared from densely packed silver nanoparticles (AgNPs) of two different sizes. We controlled the particle size during the synthetic process by controlling the temperature. Varying the concentration of the ligand also allowed us to optimize the arrangement of the AgNPs to achieve liquid mirrors exhibiting high specular reflectance. Scanning electron microscopy and atomic force microscopy confirmed that the particles of the liquid mirror were well-packed with an interparticle distance of merely 2 nm; thus, the interstices and surface roughness of the NPs were effectively minimized. As a result of decreased scattering loss, the reflectance in the shorter wavelength regime was increased effectively. The AgNP film was also sufficiently thick to reflect the light in the longer wavelength regime. In addition, we used three-dimensional finite-difference time domain simulations and experimental measurements to investigate the relationship between the localized surface plasmon resonance (LSPR) and the specular reflection of the liquid mirrors. By changing the packing density of the AgNPs, we found that the LSPR effect could yield either a specular reflection peak or dip at the LSPR wavelengths in the reflection spectra of the liquid mirrors. Relative to previously reported liquid mirrors, the reflectance of our system is obviously much greater, especially in the shorter wavelength regime. The average reflectance in the range from 400 to 1000 nm could reach 77%, comparable with that of mercury-based liquid mirrors.

D-ribose-5-phosphate isomerase from spinach: heterologous overexpression, purification, characterization, and site-directed mutagenesis of the recombinant enzyme

A cDNA encoding spinach chloroplastic ribose-5-phosphate isomerase (RPI) was cloned and overexpressed in Escherichia coli, and a purification scheme for the recombinant enzyme was developed. The purified recombinant RPI is a homodimer of 25-kDa subunits and shows kinetic properties similar to those of the homodimeric enzyme isolated from spinach leaves (A. C. Rutner, 1970, Biochemistry 9, 178-184). Phosphate, used as a buffer in previous studies, is a competitive inhibitor of RPI with a K(i) of 7.9 mM. D-Arabinose 5-phosphate is an effective inhibitor, while D-xylulose-5 phosphate is not, indicating that the configuration at carbon-3 contributes to substrate recognition. Although D-arabinose 5-phosphate binds to RPI, it is not isomerized, demonstrating that the configuration at carbon-2 is crucial for catalysis. Alignment of RPI sequences from diverse sources showed that only 11 charged amino acid residues of the 236-residue subunit are conserved. The possible function of four of these residues was examined by site-directed mutagenesis. D87A, K100A, and D90A mutants show greatly diminished k(cat) values (0. 0012, 0.074, and 0.38% of the wild type, respectively), while E91A retains substantial activity. Only insignificant or moderate changes in K(m) of D-ribose 5-phosphate are observed for D87A, K100A, and D90A, indicating a direct or indirect catalytic role of the targeted residues.

D-Ribulose-5-phosphate 3-epimerase: cloning and heterologous expression of the spinach gene, and purification and characterization of the recombinant enzyme

We have achieved, to our knowledge, the first high-level heterologous expression of the gene encoding D-ribulose-5-phosphate 3-epimerase from any source, thereby permitting isolation and characterization of the epimerase as found in photosynthetic organisms. The extremely labile recombinant spinach (Spinacia oleracea L.) enzyme was stabilized by DL-alpha-glycerophosphate or ethanol and destabilized by D-ribulose-5-phosphate or 2-mercaptoethanol. Despite this lability, the unprecedentedly high specific activity of the purified material indicates that the structural integrity of the enzyme is maintained throughout isolation. Ethylenediaminetetraacetate and divalent metal cations did not affect epimerase activity, thereby excluding a requirement for the latter in catalysis. As deduced from the sequence of the cloned spinach gene and the electrophoretic mobility under denaturing conditions of the purified recombinant enzyme, its 25-kD subunit size was about the same as that of the corresponding epimerases of yeast and mammals. However, in contrast to these other species, the recombinant spinach enzyme was octameric rather than dimeric, as assessed by gel filtration and polyacrylamide gel electrophoresis under nondenaturing conditions. Western-blot analyses with antibodies to the purified recombinant enzyme confirmed that the epimerase extracted from spinach leaves is also octameric.

Roles and microenvironments of tryptophanyl residues of spinach phosphoribulokinase

Phosphoribulokinase is one of several Calvin cycle enzymes that are light-regulated via the ferredoxin-thioredoxin system (R. A. Wolosiuk and B. B. Buchanan, 1978, Arch. Biochem. Biophys. 189, 97-101). Substitution of the only two Trp residues of the enzyme was prompted by the following goals: to identify each tryptophanyl residue with respect to prior classifications as exposed and buried (C. A. Ghiron et al., 1988, Arch. Biochem. Biophys. 260, 267-272); to explore the possible active-site location and function of conserved Trp155, as suggested by sequence proximity to catalytic Asp160 (H. A. Charlier et al., 1994, Biochemistry 33, 9343-9350); and to determine if fluorescence of a Trp residue can serve as a gauge of conformational differences between the reduced (active) and the oxidized (inactive) forms of the enzyme. Emission spectra and acrylamide quenching data demonstrate that Trp155 is solvent exposed, while Trp241 is buried. Kinetic parameters of the W241F mutant are not significantly altered relative to those of wild-type enzyme, thereby discounting any requirement for Trp at position 241. While substitution of Trp155 with Phe or Ala has little impact on Vmax, the Km for Ru5P and ATP are increased substantially; the diminished affinity for ATP is particularly pronounced in the case of the Ala substitution. In further support of an active-site location of Trp155, its fluorescence emission is subject to quenching by nucleotides. Fluorescence quenching of reduced W241F by ATP gives a dissociation constant (Kd) of 37 microM, virtually identical with its Km of 46 microM, and provides for the first time a direct measurement of the interaction of the kinase with product ADP (Kd of 1.3 mM). Fluorescence quenching of oxidized W241F by ATP reveals a Kd of 28 mM; however, this weakened binding does not reflect an altered microenvironment of Trp155, as its steady-state emission and fluorescence lifetimes are unaffected by the oxidation state.

Efficient expression of the gene for spinach phosphoribulokinase in Pichia pastoris and utilization of the recombinant enzyme to explore the role of regulatory cysteinyl residues by site-directed mutagenesis

Phosphoribulokinase (PRK), unique to photosynthetic organisms, is regulated in higher plants by thioredoxin-mediated thiol-disulfide exchange in a light-dependent manner. Prior attempts to overexpress the higher plant PRK gene in Escherichia coli for structure-function studies have been hampered by sensitivity of the recombinant protein to proteolysis as well as toxic effects of the protein on the host. To overcome these impediments, we have spliced the spinach PRK coding sequence immediately downstream from the AOX1 (alcohol oxidase) promoter of Pichia pastoris, displacing the chromosomal AOX1 gene. The PRK gene is now expressed, in response to methanol, at 4-6% of total soluble protein, without significant in vivo degradation of the recombinant enzyme. This recombinant spinach PRK is purified to homogeneity by successive anion-exchange and dye-affinity chromatography and is shown to be electrophoretically and kinetically indistinguishable from the authentic spinach counterpart. Site-specific replacement of all of PRK's cysteinyl residues (both individually and in combination) demonstrates a modest catalytically facilitative role for Cys-55 (one of the regulatory residues) and the lack of any catalytic role for Cys-16 (the other regulatory residue), Cys-244, or Cys-250. Mutants with seryl substitutions at position 55 display non-hyperbolic kinetics relative to the concentration of ribulose 5-phosphate. Sulfate restores hyperbolic kinetics and enhances kinase activity, presumably reflecting conformational differences between the position 55 mutants and wild-type enzyme. Catalytic competence of the C16S-C55S double mutant proves that mere loss of free sulfhydryl groups by oxidative regulation cannot account entirely for the accompanying total inactivation.

The role of an active-site lysyl residue of spinach phosphoribulokinase as explored by site-directed mutagenesis

Based on selective labeling by ATP analogues, Lys68 of the Calvin Cycle enzyme phosphoribulokinase (PRK) from spinach has been assigned to the active-site region [Miziorko et al. (1990), J. Biol. Chem. 265, 3642-3647]. The equivalent position is occupied by lysyl or arginyl residues in the PRK from both prokaryotic and eukaryotic sources, suggesting a requirement for a basic residue at this location. To examine this possibility, we have replaced Lys68 of the spinach enzyme with arginyl, glutaminyl, alanyl, or glutamyl residues by site-directed mutagenesis. All of the mutant enzymes retain substantial kinase activity; and even in the case of the radical substitution by glutamate, the Km values for ATP and ribulose 5-phosphate are not perturbed significantly. Glutamate at position-68 may destabilize tertiary structure, because the yield of this mutant protein from transformed E. coli is quite low compared to that of the other proteins in this series. Despite the active-site proximity of Lys68, our results show that this residue does not play a key role in catalysis or substrate binding.

Genetic diversity and differentiation of indica and japonica rice detected by RFLP analysis

Genetic diversity and differentiation in indica and japonica groups of the cultivated rice (Oryza sativa L.) were studied by assaying DNA restriction fragment length polymorphisms of 12 indica and 14 japonica rice lines digested with three restriction endonucleases. A total of 49 probes were selected to represent the entire RFLP map at intervals of 20-30 cM. It was shown that 95 of the 145 possible probe/enzyme combinations, involving 43 probes and all three enzymes, detected restriction fragment length variation, and the degree of polymorphism varied greatly from one probe/enzyme combination to another. These results demonstrate that indica rice is genetically more diverse than japonica type. Significant differentiation between the two rice groups was detected by 33 probes representing 11 of the 12 rice chromosomes. It was deduced that the processes leading to differentiation involved a combination of molecular events that include base substitutions and insertion/deletions.

Manufacture of diploid/tetraploid chimeric mice

Tetraploid mouse embryos were produced by cytochalasin B treatment. These embryos usually die before completion of embryonic development and are abnormal morphologically and physiologically. The tetraploid embryos can be rescued to develop to maturity by aggregating them with normal diploid embryos to produce diploid/tetraploid chimeric mice. The diploid/tetraploid chimeric embryos are frequently abnormal: the larger the proportion of tetraploid cells, the greater the abnormality. By karyotype analysis and by the use of appropriate pigment cell markers, we have demonstrated that two of our surviving chimeras are in fact diploid/tetraploid chimeras. One surviving chimera is retarded in growth and displays neurological abnormalities. The coat color chimerism suggests that this chimera is about 50% tetraploid. Another chimera with about 10% tetraploid pigment cells in the coat is only slightly retarded in growth and is a fertile male. Tetraploid cells are distributed in many, if not all, tissues of embryos but evidently are physiologically inadequate to support completely normal development and function in the absence of substantial numbers of normal diploid cells.

Comparison of Auxin-induced and Acid-induced Elongation in Soybean Hypocotyl

Acid-induced growth was compared to auxin-induced growth. After a transient pH 4-induced increase in the elongation rate was completed, auxin could still induce an enhanced rate of elongation in soybean (Glycine max) hypocotyl segments. This auxin response occurred both when the medium was changed to pH 6 before auxin addition, and when the auxin was added directly to the pH 4 medium. This postacid response to auxin was persistent, and quite unlike a postacid response to acid, which was again shortlived. One mm N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (pH 7) inhibited the first response to auxin (the first response to auxin being similar to the acid response), but not the second response. This did not appear to be simply a hydrogen ion neutralizing effect, however, since a 50-fold increase in buffer concentration at pH 6 did not inhibit the first response. Decrease in the pH of the external medium, previously shown to occur with excised soybean hypocotyl segments, was not affected by auxin. Furthermore, this pH drop, during which the cells appear to be adjusting their external pH to about 5.4, did not result in an increased rate of elongation. Addition of auxin after the equilibrium pH had been attained did not alter the pH, but it did increase the rate of elongation, eliciting a normal auxin response. It was concluded that hydrogen ions do not mediate in long term auxin-induced elongation in soybean hypocotyl.

Two elongation responses to auxin respond differently to protein synthesis inhibition

The first and second responses to auxin react differently to the inhibition of protein synthesis by cycloheximide. It was determined that the protein with the shortest half-life, among the several necessary for the first response, is different from its counterpart among the several necessary for the second response. Specifically, the protein half-lives are 28 minutes and 11 minutes for the first and second responses, respectively.