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Biomedical subjects

Xun Li

Publications and source records attributed to Xun Li.

At least 19 recordsLinked to original sources
PubMed2026

Factors associated with periprosthetic joint infection following total knee arthroplasty: an updated systematic review and meta-analysis.

BACKGROUND: This study aimed to systematically evaluate factors associated with periprosthetic joint infection (PJI) following total knee arthroplasty (TKA), and thereby to provide evidence-based references for clinical prevention and perioperative risk stratification. METHODS: Computerized searches were conducted in the following databases from their inception until May 26, 2025: PubMed, Web of Science, Embase, the Cochrane Library, CINAHL, China National Knowledge Infrastructure, Wanfang Database, Chinese Scientific Journal Database, and Chinese Biomedical Literature Database. Two researchers independently screened the literature, extracted data, and assessed study quality. The methodological quality was assessed using the Newcastle-Ottawa Scale. Quantitative synthesis was performed when at least two studies reported comparable exposure definitions and sufficient comparator information; otherwise, narrative synthesis was used. Review Manager 5.4 software was used for the primary analysis. This study is registered on PROSPERO (CRD420251079339). RESULTS: A total of 25 observational studies were included in the qualitative synthesis, of which 24 contributed to the primary quantitative synthesis. Quantitatively pooled factors associated with PJI included male sex (OR = 1.39, 95% CI 1.27-1.51), BMI ≥30 kg/m2 (OR = 5.72, 95% CI 2.65-12.36), prolonged operative time, type 2 diabetes mellitus (OR = 2.09, 95% CI 1.45-3.01), rheumatoid arthritis (OR = 2.64, 95% CI 1.38-5.02), smoking (OR = 1.65, 95% CI 1.34-2.04), blood transfusion (OR = 2.27, 95% CI 1.59-3.25), American Society of Anesthesiologists score ≥3 (OR = 2.73, 95% CI 1.02-7.32), history of hormone therapy (OR = 4.88, 95% CI 2.90-8.22), postoperative urinary tract infection (OR = 3.59, 95% CI 1.15-11.21), intraoperative blood loss >200 ml (OR = 1.51, 95% CI 1.03-2.22), postoperative drainage tube placement duration ≥24 h (OR = 2.23, 95% CI 1.50-3.32), preoperative anemia (OR = 1.82, 95% CI 1.67-1.99), and combined pulmonary disease (OR = 5.54, 95% CI 1.93-15.96). Age was narratively summarized because its classification differed substantially across studies. CONCLUSION: Multiple demographic, comorbidity-related, and perioperative factors were associated with PJI after TKA. However, because the included studies were observational and clinically heterogeneous, these findings should be interpreted as associations rather than causal effects. Optimization of modifiable factors may help reduce the burden of PJI, but further prospective studies using standardized PJI definitions and adjusted effect estimates are required.

Humans↗
PubMed2026

Intratumoral Mycobacterium abscessus promotes cytidine deaminase mutagenesis in non-small cell lung cancer.

The intratumoral microbiota is increasingly recognized as an active component of the tumor microenvironment, yet whether it directly drives tumor mutagenesis remains unclear. Here, integrated multi-omics analysis of human non-small cell lung cancer (NSCLC) identifies Mycobacterium abscessus as a microbial determinant of APOBEC3A-associated mutagenesis. Mechanistically, the bacterial effector nucleoside diphosphate kinase (NDK) directly targets the host transcription factor IRF3 and installs a non-canonical 1-phosphohistidine modification at H263, thereby amplifying type I interferon signaling and sustaining APOBEC3A expression. This inter-kingdom phosphotransfer event links intratumoral microbial colonization to an endogenous mutational process that promotes genomic diversification. Genetic inactivation of NDK, or pharmacologic elimination using an engineered NDK-PROTAC, suppresses APOBEC3A activation and attenuates microbe driven mutagenesis. Together, these findings establish a direct microbial effector mechanism that promotes APOBEC3A-associated mutagenesis and provide a therapeutic framework to intercept microbiome driven mutagenesis in NSCLC.

Humans↗
PubMed2026

Isolation, characterization, and antibacterial activity of a novel Pasteurella multocida bacteriophage.

Pasteurella multocida is the main pathogen causing fowl cholera and poses a serious threat to the poultry industry. Current clinical control relies on antibiotics, but the prevalence of drug-resistant strains makes it urgent to develop new antibacterial strategies. In this study, a P. multocida-specific bacteriophage vB_PmuS_ZP41 was isolated and identified as a member of the family Siphoviridae by transmission electron microscopy. This phage showed lytic activity against 13 out of 19 clinical isolates of P. multocida (68.4%) and remained stable at 4-50°C and pH 3-9. The optimal multiplicity of infection was 0.01, with a latent period of 10 min and a burst size of approximately 56 PFU/cell. Whole-genome sequencing revealed that the phage genome is a double-stranded DNA of 38,592 bp, containing no virulence genes or antibiotic resistance genes, indicating good safety. In a chick infection model, phage treatment significantly improved the survival rate of infected chicks from 40% to 80%, significantly reduced bacterial loads in blood, lung, liver, and spleen, and decreased serum levels of TNF-α and IL-1β while alleviating histopathological damage. This study systematically characterized the biological properties of phage vB_PmuS_ZP41 and its antibacterial efficacy both in vitro and in vivo, providing an experimental basis and a candidate strain for the future development of phage therapy against avian pasteurellosis.

Biological characteristics↗
PubMed2006

Insulin regulation of glutathione and contractile phenotype in diabetic rat ventricular myocytes.

Cardiovascular complications of diabetes mellitus involve oxidative stress and profound changes in reduced glutathione (GSH), an essential tripeptide that controls many redox-sensitive cell functions. This study examined regulation of GSH by insulin to identify mechanisms controlling cardiac redox state and to define the functional impact of GSH depletion. GSH was measured by fluorescence microscopy in ventricular myocytes isolated from Sprague-Dawley rats made diabetic by streptozotocin, and video and confocal microscopy were used to measure mechanical properties and Ca(2+) transients, respectively. Spectrophotometric assays of tissue extracts were also done to measure the activities of enzymes that control GSH levels. Four weeks after injection of streptozotocin, mean GSH concentration ([GSH]) in isolated diabetic rat myocytes was approximately 36% less than in control, correlating with decreased activities of two major enzymes regulating GSH levels: glutathione reductase and gamma-glutamylcysteine synthetase. Treatment of diabetic rat myocytes with insulin normalized [GSH] after a delay of 3-4 h. A more rapid but transient upregulation of [GSH] occurred in myocytes treated with dichloroacetate, an activator of pyruvate dehydrogenase. Inhibitor experiments indicated that insulin normalized [GSH] via the pentose pathway and gamma-glutamylcysteine synthetase, although the basal activity of glucose-6-phosphate dehydrogenase was not different between diabetic and control hearts. Diabetic rat myocytes were characterized by significant mechanical dysfunction that correlated with diminished and prolonged Ca(2+) transients. This phenotype was reversed by in vitro treatment with insulin and also by exogenous GSH or N-acetylcysteine, a precursor of GSH. Our data suggest that insulin regulates GSH through pathways involving de novo GSH synthesis and reduction of its oxidized form. It is proposed that a key function of glucose metabolism in heart is to supply reducing equivalents required to maintain adequate GSH levels for the redox control of Ca(2+) handling proteins and contraction.

Animals↗
PubMed2006

Inhibitors of unactivated p38 MAP kinase.

Inhibition of the p38 map kinase pathway has been shown to be beneficial in the treatment of inflammatory diseases. The first class of potent p38 kinase inhibitors was the pyridinylimidazole compounds from SKB. Since then several pyridinylimidazole-based compounds have been shown to inhibit activated p38 kinase in vitro and in vivo. We have developed a novel series of pyridinylimidazole-based compounds, which potently inhibit the p38 pathway by binding to unactivated p38 kinase and only weakly inhibiting activated p38 kinase activity in vitro.

Animals↗
PubMed2006

Analysis and comparison of impairments in differential phase-shift keying and on-off keying transmission systems based on the error probability.

The effect of nonlinear phase noise in dispersion-managed optical transmission systems is studied. The variance of the nonlinear phase noise in systems based on differential phase-shift keying (DPSK) in the presence of dispersion is examined analytically, and a semianalytical expression to calculate the error probability including intrachannel four-wave mixing, linear phase noise, and nonlinear phase noise for systems based on DPSK is derived. In addition, for the on-off keying (OOK) format, the formula for the error probability including amplified spontaneous emission noise and intrachannel nonlinear effects has been given. On the basis of the semianalytical expressions, we have compared the error probability of systems based on DPSK and OOK, and the results show that, to reach a given bit error rate of 10(-9) for a specific long-haul system, the difference between the signal-to-noise ratio required by the DPSK format and that required by the OOK format is around 6 dB for the launch power of 0 dBm, and the difference becomes larger as the launch power increases.

Journal Article↗
PubMed2006

Immune responses in mice induced by prime-boost schemes of the Plasmodium falciparum apical membrane antigen 1 (PfAMA1)-based DNA, protein and recombinant modified vaccinia Ankara vaccines.

The apical membrane antigen 1 (AMA1) of malaria parasites is a leading vaccine candidate. Its expression in merozoites and sporozoites and its importance for erythrocyte and hepatocyte invasion underline the significance of both humoral and cellular immunities against this antigen in malaria protection. We have generated a DNA construct and a recombinant poxvirus (rMVA) for expressing the Plasmodium falciparum AMA1 ectodomain, produced recombinant AMA1 protein (rAMA1) and evaluated their antigenicity in mice using single and combinatory vaccine schemes. Our results showed that although vaccinations of mice by either DNA or rMVA alone did not yield high antibody responses, they had primed significant numbers of rAMA1-responsive splenocytes. Under heterologous prime-boost schemes, priming with DNA followed by boosting with rMVA or rAMA1 protein resulted in a significant increase in antibody titers. In addition, the antibody titers to AMA1 appeared to be correlated with the levels of inhibition of merozoite invasion of erythrocytes in vitro. Furthermore, different prime-boost schemes resulted in different AMA1-specific antibody isotype (IgG1/IgG2a) ratios, providing us with an indication about Th1 or Th2 responses the vaccination regimens have induced. This study has yielded useful information for further in vivo evaluation of the suitability and effectiveness of the heterologous prime-boost strategy in AMA1 vaccination.

Animals↗
PubMed2006

Vascular endothelial growth factor induction by rhinovirus infection.

Vascular participation manifested by a runny nose (rhinorrhea) is a prominent feature of the acute consequences of rhinovirus infection. Vascular endothelial growth factor (VEGF) is an angiogenic factor that also induces potent increases in vascular permeability; it is a candidate mediator of rhinorrhea in response to rhinovirus infection as well as contributing to enhanced vascular leakage in rhinovirus-linked asthma exacerbations. It has been shown that rhinovirus induces significant increases in both VEGF protein and mRNA in primary airway fibroblasts [Ghildyal et al. (2005): J Med Virol 75:608-615]. The current studies assessed VEGF responses to rhinovirus in primary culture airway epithelium, in epithelial and fibroblast cell lines and in rhinovirus-infected nasal secretions. Epithelial and fibroblast cells were infected with rhinovirus serotype 16 and VEGF protein and isoforms assessed by ELISA and RT-PCR, respectively. VEGF protein was released by both epithelial and fibroblast cell lines and primary airway epithelial cells in culture but was not increased following rhinovirus infection. PCR products coding for four or five of the six known VEGF isoforms were produced (121, 145, 165 and 183, and/or 189 amino acids) in cell lines and primary culture cells, but no specific isoform was linked to rhinovirus infection. Nasal VEGF was also measured in a cohort of asthmatics with verified rhinovirus and respiratory syncytial virus (RSV) infection. VEGF was not raised following rhinovirus infection alone, but was increased significantly if concomitant RSV infection was present. The data suggest that fibroblasts rather than the epithelium may play a key role in VEGF mediated vascular responses after rhinovirus infection. This may aid recruitment of inflammatory cells and contribute to airway inflammation and bronchial obstruction.

Asthma↗
PubMed2005

Design, synthesis, and evaluation of novel galloyl pyrrolidine derivatives as potential anti-tumor agents.

A series of novel galloyl pyrrolidine derivatives were synthesized as potential anti-tumor agents. Their inhibiting activities on gelatinase (MMP-2 and -9) were tested with succinylated gelatin as the substrate. Structure-activity analyses demonstrate that introduction of longer and more flexible side chains at the C(4) position of the pyrrolidine ring brings higher activity against gelatinase. Free phenol hydroxyl group is more favorable than the methylated one, which confirms the important role of the phenol hydroxyl group when inhibitors interact with gelatinase. In particular, (2S,4S)-4-(3-(3,4-dimethoxyphenyl)acrylamido)-N-hydroxy-1-(3,4,5- trimethoxybenzoyl)pyrrolidine-2-carboxamide (18) stood out as the most attractive compound (IC(50) = 0.9 nM). The anti-metastasis model of mice bearing H(22) tumor cells was used to evaluate their anti-tumor activities in vivo. The assay in vivo revealed that most of these inhibitors displayed favorable inhibitory activities (inhibitory rate >35%) and no significant toxic effects were observed. The inhibition for 62.37% of 19 indicates the strategy used to design MMP inhibitors (MMPIs) of galloyl pyrrolidine derivatives as potential anti-tumor agents is promising.

Animals↗
PubMed2005

[DNA/MVA combined immunization: antibody response to Plasmodium falciparum merozoite surface protein 1 in mice].

OBJECTIVE: To explore the effect of DNA/MVA combined immunization in enhancing antibody response to MSP1. METHODS: DNA vaccine and recombined MVA were constructed based on synthesized MSP1 gene (3D7). BALB/c mice were primed with DNA solely or together with GM-CSF expressing plasmid and then boosted with rMVA/ 190. Serum IgG and subtype IgG1 and IgG2a were assayed by ELISA. All mice were challenged with allelic replaced Plasmodium berghei. RESULTS: Antibodies to MSP1-190 were detected after DNA immunization with an end-point dilution titer of 1:2500. When GM-CSF plasmid was added, the antibody end-point dilution titer reached 1:11150, with an increase of 53 and 10 times respectively after MVA boosting. Among them anti-19000 antibodies were prominent, 1/4-1/3 of total IgG in serum. However, when the mice were challenged with Pb-PfM19 no prolonged survival was observed (P>0.05). CONCLUSION: High titer antibodies can be elicited in mice by using codon optimized MSPI gene and DNA/MVA combined immunization. The specificity and protection of these antibodies is being further investigated.

Animals↗
PubMed2005

Rhinovirus infects primary human airway fibroblasts and induces a neutrophil chemokine and a permeability factor.

The events linking rhinovirus (RV) infection to airway symptoms are poorly understood. The virus initially infects airway epithelium followed by a vigorous inflammatory response that may entail spread of RV from epithelium to other cells in the airway wall. However, RV has fastidious growth characteristics and to date reproductive infection of primary cells other than human airway epithelium has not been confirmed. Airway fibroblasts are adjacent to and in contact with epithelial cells, play a key role in innate immune responses, and may participate in the evolution of inflammation. To investigate fibroblast actions, we first determined whether RV could infect and replicate in primary culture human lung fibroblasts. RV serotype 16 (RV16) was used to infect fibroblasts grown from lung tissue, and virus infection with replication was demonstrated by a combination of techniques. RT-PCR was used to show an increase in RV transcription; confocal microscopy demonstrated colocalization of the replicative form of RV genome (double-stranded RNA) and RV16 proteins; infectious virus was also recovered from the culture supernatant of infected fibroblasts. Functional consequences of RV infection were next examined. RV infection of fibroblasts was followed by an increase in epithelial neutrophil-activating peptide-78 (ENA-78) mRNA and protein. The permeability factor vascular endothelial growth factor (VEGF) was also induced over a similar time course. These data suggest that interactions between RV and human fibroblasts are feasible, may coordinate neutrophil chemoattraction with enhanced vascular permeability and that fibroblasts may contribute to inflammatory responses following RV infections.

Cells, Cultured↗
PubMed2005

Expression, purification and characterization of a recombinant beta-glucosidase from Volvariella Volvacea.

For the first time, a beta-glucosidase gene from the edible straw mushroom, Volvariella volvacea V1-1, has been over-expressed in E. coli. The gene product was purified by chromatography showing a single band on SDS-PAGE. The recombinant enzyme had a molecular mass of 380 kDa with subunits of 97 kDa. The maximum activity was at pH 6.4 and 50 degrees C over a 5 min assay. The purified enzyme was stable from pH 5.6-8.0, had a half life of 1 h at 45 degrees C. The beta-glucosidase had a K(m) of 0.2 mM: for p-nitrophenyl-beta-D: -glucopyranoside.

Agaricales↗
PubMed2005

[Raman spectrum of nano-graphite synthesized by explosive detonation].

The nano-graphite powder synthesized by the detonation of explosives with negative oxygen balance is a new powder material with potential applications. In this work, the preparation of nano-graphite powder in steel chamber by pure TNT (trinitrotoluene) explosives has been introduced. In the synthesis process, the protective gases in the steel chamber are N2, CO2 and Ar, and the pressure is 0.25-2 atm. Raman spectrum of the nano-graphite was measured. The characteristic Raman band assigned to sp2 of graphite has been observed at about 1 585 cm(-1) with half-peak width of 22 cm(-1). The peak shifted to a higher frequency by 5 cm(-1) compared with that of bulk graphite. The authors explain this blue shift phenomenon by size effect. The average size of nanographite from Raman measurement is 2.97-3.97 nm. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to measure the structure and particle size of the nano-graphite. The crystallite size of nano-graphite estimated from XRD andTEM are 2.58 nm (acid untreated) and 1.86 nm (acid treated) respectively, which is in accord with the results of the measurement approximately.

Argon↗
PubMed2005

[Treating renal carcinoma with ablation or ablation combined with 125I seed implantation: a report of eleven cases].

BACKGROUND & OBJECTIVE: Recently, multi-needles radiofrequency ablation and brachyradiotherapy have been used to treat some solid tumors, such as liver cancer and prostate cancer. This study was to explore the feasibility and efficacy of radiofrequency ablation or ablation combined with 125I seed implantation on treating renal carcinoma. METHODS: From Jun. 2000 to Feb. 2004, 11 patients with a total of 13 renal carcinoma lesions were treated with ablation or ablation combined with (125)I seed implantation, including 6 cases of renal carcinoma of solitary kidney, 2 cases of renal carcinoma combined with contralateral renal atrophy resulted from ureteric stone, 1 case of bilateral tumor, and 2 cases with general conditions contraindicated to surgery. Of the 13 lesions, 1 was resected by open operation, 6 were treated with multi-needles radiofrequency ablation, and 6 were treated with ablation and simultaneous (125)I seed implantation around tumor margin. RESULTS: The patients were followed-up for 6-46 months (mean 27 months). One patient died of cardiac muscle infarction 4 months after operation. Of the 10 alive patients, 2 with recurrent tumors 7 months and 13 months after operation were treated with ablation again, 1 with postoperative uremia was treated with intermittent peritoneal dialysis, the rest 7 had normal renal function. CONCLUSION: Multi-needles radiofrequency ablation or ablation combined with (125)I seed implantation would be an option in the treatment for patients with renal carcinoma of solitary kidney or bilateral kidney lesions, or for patients can't suffer from surgery.

Adult↗
PubMed2005

[Charactierization of a new antibacterial polypeptide isolated from human cervical mucas].

OBJECTIVE: To identify a new antibactrial polypeptide HCP-1 isolated from human cervical mucus. METHODS: HCP-1 was isolated and purified from human cervical mucus, and N-terminal sequence of HCP-1 was determined. A degenerate primer was designed according to CodeHop methods, and an "anchor-oliga-dT primer" was used for the synthesis of cDNA. Using the degenerate primer and anchor-primer, cDNAs were amplified by PCR. The PCR products were cloned, sequenced, and analyzed by biological software. RESULTS: N-terminat sequence of HCP-1 was PKRKAEGDAK. The full length of HCP-1 cDNA was isolated and of which the sequence was the same as HMG-17. OMIGA software analysis indicated that this molecule contained an alpha-helix region. CONCLUSION: The new antibacterial polypeptide isolated from human cervical mucus is HMG-17. It may play a role in the human cervical mucus and the alpha-helix domain may be its antibacterial activity region.

Adult↗
PubMed2005

[Production of polyclonal antibody against HBD-2 by immunization with recombinant GST-HBD-2 fusion protein].

For the purpose of detecting the HBD-2 expression at protein level, the recombinant prokaryotic expression vector pGEX-1lambdaT-HBD-2 was constructed and the E. coli-based product of GST-HBD-2 fusion protein was prepared. When rabbit was immunized with the fusion protein, the anti-serum against HBD-2 was produced. After caprylic acid and ammonium sulfate precipitation, high titer of specific polyclonal antibody against HBD-2, which was detected by ELISA and Western blot, was obtained. This result suggests that recombinant peptide fusion protein could be used instead of the conjugate of peptide-albumin or peptide-thyroid globulin to produce antibody. The obtained antibodies could be used for revealing the tissue distribution of HBD-2 and the regulation of its gene expression.

Animals↗
PubMed2005

[Studies on nano-diamond prepared by explosive detonation by Raman and infrared spectroscopy].

Nano-diamond was synthesized by TNT/RDX explosives detonation in a steel chamber and characterized by X-ray diffraction (XRD), laser Raman spectroscopy, and infrared spectroscopy. XRD results indicate that nano-diamond has cubic diamond structure. The parameter of unit cell of nano-diamond is 0.359 23 nm and is 0.72% larger than that of the bulk diamond. The high-density defects and other impurity atoms in the nano-diamond structure may lead to the large lattice constant. The examination results of Raman spectra show that the Raman band is broader and shifts to l ow frequency by 3 cm(-1), because the size of nano-diamond reaches nanometer order. There is little graphite in the nano-diamond. There are two peaks in FTIR of the nano-diamond, which are characteristic peaks of diamond at 1 262 and 1 134 cm(-1). Besides these two peaks, there are six peaks at 3 422, 1 643, 2 971, 2 930, 2 857 and 1 788 cm(-1) respectively. The FTIR bands at 2 930 and 2 857 cm(-1) are the antisymmetrical and symmetrical stretch vibration absorption spectra of CH2 respectively. The 3 422 cm(-1) is the stretch vibration absorption peak of O-H. The 1 634 cm(-1) confirms that there are H2O in the nano-diamond. The 2 971 cm(-1) is the antisymmetrical stretch vibration absorption peak of CH3. The 1 788 cm(-1) is the stretch vibration absorption peak of C=O. These indicate that there are H and O elements in the nano-diamond. From the mechanism of the nano-diamond, the authors discuss the reason for the vibration absorption peaks of O-H, CH2, CH3, and C=O, existing in the FTIR of the nano-diamond.

Algorithms↗