ObjectiveOxygen partial pressure (pO₂) is a critical indicator of the tumor microenvironment and plays an essential role in regulating tumor progression and therapeutic response, particularly for oxygen-dependent treatments such as photodynamic therapy (PDT). Although photoacoustic imaging (PAI) has shown great potential for functional and molecular imaging, conventional oxygenation imaging approaches based on hemoglobin absorption mainly provide relative oxygen saturation information and cannot directly quantify tissue oxygen partial pressure. Therefore, this study aimed to develop a fast laser sequence-based pump-probe photoacoustic tomography (PP-PAT) system for quantitative, non-invasive, and dynamic monitoring of oxygen partial pressure in tumor tissues. MethodsThe proposed PP-PAT system was developed based on the oxygen-sensitive triplet-state lifetime characteristics of methylene blue (MB). Upon optical excitation, MB molecules undergo transitions from the ground state to an excited state and subsequently form metastable triplet states through intersystem crossing. The lifetime of the triplet state is strongly affected by surrounding oxygen concentration due to dynamic oxygen quenching, providing a direct correlation between triplet-state kinetics and local oxygen partial pressure. A dual-wavelength pump-probe excitation scheme was implemented to selectively interrogate MB triplet-state dynamics. The pump pulse was used to initiate the triplet-state population, while the delayed probe pulse was applied to detect the transient triplet-state response. By optimizing the temporal interval between the pump and probe pulses, transient triplet-state differential (TTD) signals were extracted to enhance the specificity of oxygen-dependent molecular information and suppress background interference from conventional photoacoustic signals. The performance of the PP-PAT system was systematically evaluated through phantom and in vivo experiments. First, a single-tube phantom containing MB solution was used to investigate signal stability, reproducibility, and the influence of signal averaging on imaging quality. Subsequently, a dual-tube phantom model was established to simulate oxygen consumption during PDT, where one MB-containing tube was exposed to laser irradiation and the other served as a control. Finally, in vivo experiments were performed using a subcutaneous tumor model in nude mice. MB was locally injected into the tumor region before imaging to evaluate the feasibility of tumor oxygen partial pressure mapping using the proposed PP-PAT system. ResultsPhantom experiments demonstrated that the extracted TTD signals exhibited high stability and effectively reflected MB triplet-state dynamics while reducing non-specific background contributions. Signal averaging significantly improved the signal-to-noise ratio, and 50 repeated acquisitions provided an optimal compromise between image quality and acquisition efficiency. In the dual-tube phantom experiments, continuous PDT irradiation induced progressive oxygen depletion in the treated sample. The corresponding TTD decay rate gradually decreased, accompanied by an increase in the calculated triplet-state lifetime, indicating reduced oxygen quenching and decreased oxygen partial pressure. In contrast, the control sample showed relatively stable TTD kinetics and oxygenation levels during the same period. These results demonstrated that PP-PAT could quantitatively characterize oxygen consumption dynamics associated with photochemical reactions. In vivo experiments further demonstrated the capability of PP-PAT for spatially resolved oxygen partial pressure imaging in MB-injected tumor tissues. The reconstructed pO₂ maps revealed heterogeneous oxygen distributions within tumors, showing relatively hypoxic regions in the tumor core and higher oxygenation levels near the tumor boundary. This spatial oxygen distribution pattern was consistent with the typical physiological characteristics of solid tumors, where abnormal vascular structures and limited oxygen diffusion result in intratumoral oxygen gradients. ConclusionThis study presents a fast laser sequence-based PP-PAT system capable of quantitative and non-invasive imaging of tissue oxygen partial pressure. By utilizing the oxygen-dependent triplet-state lifetime of MB and extracting TTD signals, the proposed method provides molecularly specific information related to oxygen dynamics beyond conventional photoacoustic oxygenation imaging. The system enables dynamic monitoring of oxygen consumption during PDT and reveals spatial oxygen heterogeneity within tumors. This technique provides a promising imaging approach for tumor hypoxia characterization, evaluation of oxygen-dependent therapeutic responses, and precision-guided cancer treatment.

Plutonium isotopes(238Pu,239Pu,240Pu and 241Pu)in the environment are important"fingerprint"nuclides in the study of nuclear activity traceability.The content of plutonium isotopes in the environmental metrics is usually very low,and the measurement of these isotopes,especially 238Pu,using mass spectrometry is seriously interfered with by the coexisting 238U.The analysis of several plutonium isotopes in soil usually requires combination of multiple measurement techniques,which leads to a long analysis time and large uncertainty in the isotope ratio.In this work,the hydrous titanium oxide(HTiO)precipitated by the hydrolysis of titanium oxydichloride(TiOCl2)under near-neutral condition was used to preconcentrate plutonium from the soil digestion solution,and the highly efficient decontamination of 238U in the sample was achieved by TK200 resin column chromatography with a decontamination factor of 108.Simulation resuts of density functional theory(DFT)showed that NH3 was considered as a promising reaction gas to eliminate the interference of 238U from 238Pu measurement using mass spectrometry due to the significant discrepancy of the chemical reactivity of U+and Pu+with the reactive gas NH3.Experiments confirmed that by optimizing the flow rates of collision gas(He)and reaction gas(NH3),the interference of 238U could be effectively suppressed,and the decontamination factor of 238U was 104.Combined with chemical separation,the overall decontamination factor of 238U could reach 1012 by using the developed method.By combining chemical separation and tandem quadrupole inductively coupled plasmon-mass spectrometry(ICP-MS/MS)measurement,the simultaneous determination of four ultra-trace plutonium isotopes in soil was realized,and the detection limit of plutonium isotopes was at the femtogram level.Analysis of the international standard reference materials(NIST-SRM-4357 and IAEA-384)showed that the established method could be successfully used for the accurate analysis of ultra-trace four plutonium isotopes(238Pu,239Pu,240Pu and 241Pu)in soil samples.

As the simplest label-free single-molecule analytical technique in solution,nanopore technology has been widely used in rapid sequencing of protein and nucleic acid,and single-molecule sensing.However,the main challenge is to get this technology out of the lab and achieve automation,miniaturization as well as rapid analysis at high throughput.In this work,a new microfluidic tubing protein nanopore analysis system was designed and constructed by combining microfluidic and nanopore nanofluidic analysis techniques.An arcuate lipid bilayer was formed in the microfluidic device through lipid monolayer at the oil/water interface by developed aperture processing technology at 10 μm level.The arcuate lipid bilayer with the life span of more than 98 h had high biomimetic fluidity and biological activity by which protein channel could be produced and sealed at 18 GΩ level without leakage.When applied+40 mV potential,relative standard deviation of single proteinα-hemolysin mutant(α-HL(M113F/K147N))channel current was less than 0.16 pA(n=3)in 10 mmol/L Tris-HCl(pH 7.4)buffer containing 1 mol/L NaCl.Single-molecule detection for aptamer and its host-guest interactions with biotin in protein channel demonstrated that this microfluidic tube protein nanopore sensor could well work with high sensitivity without the need of anti-vibration table and shielding cage.

Aim To investigate the effect of neogam-bogic acid(NGA)on inducing ferroptosis in osteosar-coma K7M2 cells and subcutaneous transplanted tumor mice and explore the underlying mechanism.Methods MTT assay was employed to detect the effect of NGA(1,2,4,8,16,32,64,128 μmol·L-1)on cell prolif-eration,and the IC50 value was calculated.Calcein AM assay was used to detect cell viability.Transwell was applied to detect cell invasion.TEM was utilized to ob-serve the mitochondria morphology.K7M2 cells were subjected to treat with ferroptosis inducers erastin(Era)and inhibitors ferrostatin-1(Fer-1)to assess the levels of MDA,GSH,Fe2+,and LDH.RT-qPCR and Western blot were used to detect the mRNA and protein expression of STAT3,GPX4,and SLC7A11.A transplanted tumor model was established and treated with NGA to assess the impact of it on tumor growth and ferroptosis in vivo.HE staining was applied to ana-lyze the pathological status of tumor tissues.Nile red fluorescence staining was applied to detect the level of lipid components in tumor tissues.Results The pro-liferation,viability and invasion ability of K7M2 cells were significantly reduced after treatment with NGA at different concentrations(P＜0.05),and typical fea-tures of ferroptosis such as decreased mitochondrial vol-ume and reduced mitochondrial spine were observed.Compared to the control,the expression of MDA,Fe2+and LDH significantly increased(P＜0.01),while the content of GSH significantly decreased(P＜0.01).The ferroptosis in osteosarcoma was enhanced by the erastin,while inhibited by ferrostatin-1.In terms of mechanism,NGA inhibited the mRNA and protein ex-pression levels of STAT3,GPX4 and SLC7A11(P＜0.05).In vivo experiments confirmed that NGA signif-icantly improved the pathological state of tumor tissues,inhibited tumor growth,and induced ferroptosis in os-teosarcoma tissue cells.Conclusion NGA induces ferroptosis in osteosarcoma cells both in vitro and in vi-vo by inhibiting the STAT3/GPX4/SLC7A11 signaling axis,thereby exerting an anti-osteosarcoma effect.

OBJECTIVE: This study reports the first imported case of Lassa fever (LF) in China. Laboratory detection and molecular epidemiological analysis of the Lassa virus (LASV) from this case offer valuable insights for the prevention and control of LF. METHODS: Samples of cerebrospinal fluid (CSF), blood, urine, saliva, and environmental materials were collected from the patient and their close contacts for LASV nucleotide detection. Whole-genome sequencing was performed on positive samples to analyze the genetic characteristics of the virus. RESULTS: LASV was detected in the patient's CSF, blood, and urine, while all samples from close contacts and the environment tested negative. The virus belongs to the lineage IV strain and shares the highest homology with strains from Sierra Leone. The variability in the glycoprotein complex (GPC) among different strains ranged from 3.9% to 15.1%, higher than previously reported for the seven known lineages. Amino acid mutation analysis revealed multiple mutations within the GPC immunogenic epitopes, increasing strain diversity and potentially impacting immune response. CONCLUSION The case was confirmed through nucleotide detection, with no evidence of secondary transmission or viral spread. The LASV strain identified belongs to lineage IV, with broader GPC variability than previously reported. Mutations in the immune-related sites of GPC may affect immune responses, necessitating heightened vigilance regarding the virus.
Humans ; China/epidemiology* ; Genome, Viral ; Lassa Fever/virology* ; Lassa virus/classification* ; Molecular Epidemiology ; Phylogeny

Aim To investigate the effect of neogam-bogic acid(NGA)on inducing ferroptosis in osteosar-coma K7M2 cells and subcutaneous transplanted tumor mice and explore the underlying mechanism.Methods MTT assay was employed to detect the effect of NGA(1,2,4,8,16,32,64,128 μmol·L-1)on cell prolif-eration,and the IC50 value was calculated.Calcein AM assay was used to detect cell viability.Transwell was applied to detect cell invasion.TEM was utilized to ob-serve the mitochondria morphology.K7M2 cells were subjected to treat with ferroptosis inducers erastin(Era)and inhibitors ferrostatin-1(Fer-1)to assess the levels of MDA,GSH,Fe2+,and LDH.RT-qPCR and Western blot were used to detect the mRNA and protein expression of STAT3,GPX4,and SLC7A11.A transplanted tumor model was established and treated with NGA to assess the impact of it on tumor growth and ferroptosis in vivo.HE staining was applied to ana-lyze the pathological status of tumor tissues.Nile red fluorescence staining was applied to detect the level of lipid components in tumor tissues.Results The pro-liferation,viability and invasion ability of K7M2 cells were significantly reduced after treatment with NGA at different concentrations(P＜0.05),and typical fea-tures of ferroptosis such as decreased mitochondrial vol-ume and reduced mitochondrial spine were observed.Compared to the control,the expression of MDA,Fe2+and LDH significantly increased(P＜0.01),while the content of GSH significantly decreased(P＜0.01).The ferroptosis in osteosarcoma was enhanced by the erastin,while inhibited by ferrostatin-1.In terms of mechanism,NGA inhibited the mRNA and protein ex-pression levels of STAT3,GPX4 and SLC7A11(P＜0.05).In vivo experiments confirmed that NGA signif-icantly improved the pathological state of tumor tissues,inhibited tumor growth,and induced ferroptosis in os-teosarcoma tissue cells.Conclusion NGA induces ferroptosis in osteosarcoma cells both in vitro and in vi-vo by inhibiting the STAT3/GPX4/SLC7A11 signaling axis,thereby exerting an anti-osteosarcoma effect.

The aim of this study is to establish an gene editing method of Mesomycoplasma hyo-pneumoniae(Mhp)based on the homologous recombination principle.The restriction enzyme di-gestion and ligation method combined with gene synthesis were used to construct a shuttle plasmid to achieve replication in both Mhp and Escherichia coli(E.coli).The pGEM?-T vector was used as the skeleton.The oriC sequence of Mhp which can achieve the replication of the plasmid in Mhp was inserted into the vector.Sequences of the Spiroplasma promoter and puromycin resistance gene were then inserted into the above constructed plasmid to screen recombinant clones.The up-stream and downstream homologous arms of p97 were constructed to initiate homologous recombination.The recA gene of E.coli is inserted to improve the efficiency of homologous recom-bination.The obtained shuttle plasmid was then delivered into Mhp by electro-transformation or chemical transformation.A shuttle plasmid,pGEM?-Mhp-oriC-p 97,which can replicate in both Mhp and E.coli was constructed.With the transformation of this plasmid,the carried puromycin gene and recA gene can be expressed,the p97 gene can be edited.Finally,the genetically unstable p97 gene mutant was initially obtained.In this study,a tool for Mhp gene editing based on the principle of homologous recombination was established,which laid a foundation for the develop-ment of tools for studying the pathogenesis of Mhp.

BACKGROUND:The highest incidence of spinal fracture is in the thoracolumbar segment,and its symptoms are back pain,posterior convexity deformity,activity limitation,or with spinal cord nerve injury causing lower limb pain,numbness,and even paraplegia and other complications.The finite element method is a digital computer modeling technique,which can simulate the physical model and carry out force analysis realistically.OBJECTIVE:To review the application of finite element method in thoracolumbar spine fractures.METHODS:We searched the Chinese and English literature databases PubMed,Web of Science,and CNKI for relevant literature on the application of the finite element analysis method in spinal thoracolumbar fracture published before March 2024.The search terms in Chinese and English were:finite element analysis methods,biomechanical phenomena,stress analysis,thoracolumbar fractures,spinal fractures.Finally,55 papers were included.RESULTS AND CONCLUSION:(1)The exploration of thoracolumbar fractures caused by different etiologies(osteoporotic,traumatic,and pathological)through the finite element method is conducive to a deeper understanding of the biomechanics of various types of thoracolumbar fractures,and to improve the individualized and fine-tuned treatment of thoracolumbar fractures.(2)The finite element analysis of a single sample or a small number of samples has the chance,and a larger number of samples are required for the future finite element analysis to reduce the chance caused by the sample.(3)The rigid structure of bones alone cannot meet the biomechanical working conditions of the integrity of the physical object,and future finite element models need to incorporate all the structures of the physical object(e.g.,soft tissues,such as muscles and ligaments)as far as possible.(4)The finite element method has been used in more studies on osteoporotic and traumatic thoracolumbar spine fractures,which will need to be more in-depth in the future,and less in the field of pathologic thoracolumbar fractures,which has a wider scope for future research.

AIM To investigate the effects of volatile oil from Acorus tatarinowii Schott(A.tatarinowii)on neuroinflammation in a rat model of tic disorders.METHODS The SD rats were randomly divided into the blank group(8 rats)and the model group(40 rats).The rat models of tic disorders established successfully by intraperitoneal injection of iminodiapropionitrile(IDPN)were further divided into the model group,the tiapride group and the high-dose,moderate-dose and low-dose A.tatarinowii volatile oil groups,with 8 rats in each group.The 4-week intragastric treatment of respective drug was initiated the next day after the completion of modeling,and normal saline was dosed upon the blank group and the model group,during which the rats' behavioral changes were assessed by stereotyped behavior and motor behavior score every week.After the administration,the rats had their morphological changes of striatal neurons observed by Nissl staining;their levels of TGF-β,IL-10,TNF-αand IL-1β in serum and striatum detected by ELISA;their striatal protein expressions of CX3CL1 and CX3CR1 detected by Western blot and immunohistochemistry;and their striatal expressions of M1,M2 microglia marker proteins CD86,CD206,SYN and PSD-95 detected by immunofluorescence co-staining.RESULTS Compared with the model group,the A.tatarinowii volatile oil groups demonstrated improved twitch-like behavior;decreased scores of motor behavior and rigid behavior(P＜0.01);alleviated damage of Nissl bodies in neurons;increased serum and striatum levels of TGF-β and IL-10(P＜0.05,P＜0.01);decreased levels of TNF-α and IL-1β(P＜0.01);decreased striatal protein expressions of CX3CL1 and CX3CR1(P＜0.01);increased protein expressions of PSD95 and SYN(P＜0.05,P＜0.01);and decreased CD86/Iba1(P＜0.01)and increased CD206/Iba1(P＜0.01)in terms of the fluorescence intensity.CONCLUSION A.tatarinowii volatile oil contributes an anti-tic effect and improves the neuroinflammation in the brain of the rat model of tic disorders by promoting the transformation of microglia into M2 type via CX3CL1/CX3CR1 signal axis.

Researchers commonly use cyclization recombination enzyme/locus of X-over P1 (Cre/loxP) technology-based conditional gene knockouts of model mice to investigate the functional roles of genes of interest in Sertoli and Leydig cells within the testis. However, the shortcomings of these genetic tools include high costs, lengthy experimental periods, and limited accessibility for researchers. Therefore, exploring alternative gene silencing techniques is of great practical value. In this study, we employed adeno-associated virus (AAV) as a vector for gene silencing in Sertoli and Leydig cells. Our findings demonstrated that AAV serotypes 1, 8, and 9 exhibited high infection efficiency in both types of testis cells. Importantly, we discovered that all three AAV serotypes exhibited exquisite specificity in targeting Sertoli cells via tubular injection while demonstrating remarkable selectivity in targeting Leydig cells via interstitial injection. We achieved cell-specific knockouts of the steroidogenic acute regulatory ( Star ) and luteinizing hormone/human chorionic gonadotropin receptor (Lhcgr) genes in Leydig cells, but not in Sertoli cells, using AAV9-single guide RNA (sgRNA)-mediated gene editing in Rosa26-LSL-Cas9 mice. Knockdown of androgen receptor ( Ar ) gene expression in Sertoli cells of wild-type mice was achieved via tubular injection of AAV9-short hairpin RNA (shRNA)-mediated targeting. Our findings offer technical approaches for investigating gene function in Sertoli and Leydig cells through AAV9-mediated gene silencing.
Animals ; Male ; Leydig Cells/metabolism* ; Mice ; Dependovirus/genetics* ; Sertoli Cells/metabolism* ; Gene Silencing ; Genetic Vectors ; Testis/cytology*