BACKGROUND:Changes in skeletal muscle mass have been indicated in studies addressing the effects of low-frequency pulsed magnetic fields on the structure and morphology of the skeletal muscle,but no relevant studies have been conducted on the morphologic changes that occur after chronic exposure to the low-frequency pulsed magnetic field. OBJECTIVE:To observe the effects of chronic exposure to low-frequency pulsed magnetic fields on the maximal voluntary contraction and morphologic indicators of the quadriceps muscle of the leg,thereby providing a reference of muscle morphologic changes for the use of this technique as a strategy for muscle function improvement. METHODS:Seventy healthy subjects were recruited and randomly divided into a test group that received magnetic field stimulation and a control group that underwent sham treatment,with 35 subjects in each group,and the total duration of the trial was 4 weeks.The test group underwent low-frequency pulsed magnetic stimulation for 15 minutes every 48 hours,while the control group underwent sham treatment,with the same intervention interval and duration as the test group.After 4 weeks of intervention,changes in the maximum voluntary contraction value of the quadriceps muscle in different groups were observed,and B-mode ultrasonography was utilized as a means of assessment to observe changes in muscle thickness,muscle cross-sectional area,and pinnation angle indexes. RESULTS AND CONCLUSION:After 4 weeks of chronic exposure to low-frequency pulsed magnetic fields,68 subjects completed the test.The maximum voluntary contraction value of the quadriceps muscle in the test group increased significantly(P=0.000),and the increment was significantly higher than that of the control group(P=0.008).Three indexes related to muscle morphology in the test group were significantly higher than the pre-test values(P=0.000),while in the control group,muscle thickness showed a significant reduction(P=0.020),there was no significant change in the pinnation angle,but a significant increase in the cross-sectional area(P=0.000).Intergroup comparisons revealed that the three indicators related to muscle morphology,including muscle thickness(P=0.012),pinnation angle(P=0.003),and cross-sectional area(P=0.049),were significantly higher in the test group than in the control group.The above data confirmed that the maximum voluntary contraction of the quadriceps muscle was significantly increased in healthy adults after 4 weeks of chronic exposure to the low-frequency pulsed magnetic field,and significant increases in the three muscle morphometric indices of muscle thickness,cross-sectional area,and pinnation angle were observed in the test group,providing a basis of muscle tissue morphology for the use of this technique as an exercise alternative and medical treatment strategy for muscle improvement.

Background Exposure to polycyclic aromatic hydrocarbons (PAHs) is associated with the development of metabolic syndrome (MS). However, the role of amino acids in PAH-induced MS remains unclear. Objective To explore the impact of PAHs exposure on the incidence of MS among coking workers, and to determine potential modifying effect of amino acid on this relationship. Methods Unmatched nested case-control design was adopted and the baseline surveys of coking workers were conducted in two plants in Taiyuan in 2017 and 2019, followed by a 4-year follow-up. The cohort comprised 667 coking workers. A total of 362 participants were included in the study, with 84 newly diagnosed cases of MS identified as the case group and 278 as the control group. Urinary levels of 11 PAH metabolites and plasma levels of 17 amino acids were measured by ultrasensitive performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Logistic regression was used to estimate the association between individual PAH metabolites and MS. Stratified by the median concentration of amino acids, Bayesian kernel machine regression (BKMR) model was employed to assess the mixed effects of PAHs on MS. Due to the skewed data distribution, all PAH metabolites and amino acids in the analysis were converted by natural logarithm ln (expressed as lnv). Results The median age of the 362 participants was 37 years, and 83.2% were male. Compared to the control group, the case group exhibited higher concentrations of urinary 2-hydroxyphenanthrene (2-OHPhe), 9-hydroxyphenanthrene (9-OHPhe), and hydroxyphenanthrene (OHPhe) (P=0.005, P=0.049, and P=0.004, respectively), as well as elevated levels of plasma branched chain amino acid (BCAA) and aromatic amino acid (AAA) (P<0.05). After being adjusted for confounding factors, for every unit increase in lnv_2-OHPhe in urine, the OR (95%CI) of MS was 1.57 (1.11, 2.26), and for every unit increase in lnv_OHPhe, the OR (95%CI) of MS was 1.82 (1.16, 2.90). Tyrosine, leucine, and AAA all presented a significant nonlinear correlation with MS. At low levels, tyrosine, leucine, and AAA did not significantly increase the risk of MS, but at high levels, they increased the risk of MS. In the low amino acid concentration group, as well as in the low BCAA and low AAA concentration groups, it was found that compared to the PAH metabolite levels at the 50th percentile (P₅₀), the log-odds of MS when the PAH metabolite levels was at the 75th percentile (P₇₅) were 0.158 (95%CI: 0.150, 0.166), 0.218 (95%CI: 0.209, 0.227), and 0.262 (95% CI: 0.241, 0.282), respectively, However, no correlation between PAHs and MS was found in the high amino acid concentration group. Conclusion Amino acids modify the effect of PAHs exposure on the incidence of MS. In individuals with low plasma amino acid levels, the risk of developing MS increases with higher concentrations of mixed PAH exposure. This effect is partly due to the low concentrations of BCAA and AAA.

BackgroundPost-traumatic stress symptoms （PTSS） is highly prevalent in adolescents who have experienced earthquake， which seriously threatens their physical and mental health， yet there is currently a lack of research on the effects of loneliness， social support and social media use on PTSS among post-earthquake adolescents. ObjectiveTo assess the PTSS among adolescents experiencing MS6.0 Luxian， Sichuan， earthquake on 16 September 2021， and to investigate the effects of loneliness， social support and social media use on PTSS， so as to provide references for the intervention of PTSS among post-earthquake adolescents. MethodsOn November 12， 2021， simple random sampling technique was used to select 2 522 post-earthquake adolescents in Luxian county of Luzhou city in Sichuan province. All subjects were assessed using Post-Traumatic Stress Disorder Checklist for DSM-5 （PCL-5）， Multidimensional Scale of Perceived Social Support （MSPSS）， Short-form UCLA Loneliness Scale （ULS-3） and Social Media Use Scale （SM-10）. Binary Logistic regression was used to determine the factors influencing PTSS among post-earthquake adolescents. ResultsPTSS was detected in 91 （3.61%） adolescents. Binary Logistic regression revealed that perceived social support from family members （OR=0.926， 95% CI： 0.879~0.976） was a protective factor for PTSS among post-earthquake adolescents. Lack of companionship （OR=1.764， 95% CI： 1.141~2.727）， feeling isolated （OR=2.037， 95% CI： 1.282~3.236）， and viewing negative emotional response of disaster victims through social media （OR=1.615， 95% CI： 1.291~2.020） were risk factors for PTSS among post-earthquake adolescents. ConclusionLack of companionship， feeling isolated， and viewing negative emotional response of disaster victims through social media pose a negative impact on PTSS among post-earthquake adolescents， while perceived social support from family members exert a positive impact on PTSS among post-earthquake adolescents. ［Funded by Humanity and Social Science Youth foundation of Ministry of Education of China （number， 22YJC190019）； Natural Science Foundation of Sichuan Province （number， 2023NSFSC1486）］

[Objective] To analyze the serological characteristics and molecular biology results for a P^k phenotype. [Methods] One patient with P^k phenotype upon unexpected antibodies at Jining Blood Center in July 2022 was selected as the study subject. The blood groups and unexpected antibodies of the proband and his second son were identified using serological methods. The sequences of 3-β-N-acetylgalactosaminyltransferase gene (B3GALNT1) and the coding region of α-1,4-galactosyltransferase gene (A4GALT) were amplified and analyzed by PCR direct sequencing, and haploid sequence analysis was carried out on the variant sites of the B3GALNT1 gene. PROVEAN, SIFT, PolyPhen2 and Mutation Taster were used to analyze the effect of mutations on the protein. [Results] Serological test results suggested that the proband was a P2^k type, including anti-P antibody in his serum, and his son was the P2 phenotype. Sequencing analysis revealed that the proband had a compound heterozygous variants of the B3GALNT1 in c. 239T>A (p. Leu80Gln) and c. 433C>T (p. Arg145Ter). Further haploid analysis showed that the c. 239T>A had occurred in one haploid while c. 433C>T was present in the other haploid, and his son carried a heterozygous variant of c. 433C>T (p. Arg145Ter); the proband and his son all have homozygous mutation variants of the A4GALT in c. 903C>G. Bioinformatic analysis also predicted that the mutations were harmful to the protein function. [Conclusion] The compound heterozygous variants c. 239T>A (p. Leu80Gln) and c. 433C>T (p. Arg145Ter) in the B3GALNT1 gene may contribute to the P^k phenotype, of which the c. 239T>A variant has not been reported.

ObjectiveTo explore the sequential effects of hypoxic exercising on miR-27/PPARγ and lipid metabolism target gene and protein expression levels in the obesity rats’ liver. Methods13-week-old male diet-induced obesity rats were randomly divided into three groups (n＝10): normal oxygen concentration quiet group (N), hypoxia quiet group (H), hypoxic exercise group (HE). Exercise training on the horizontal animal treadmill for 1 h/d, 5 d/week for a total of 4 week, and the intensity of horizontal treadmill training was 20 m/min (hypoxic concentration was 13.6%). Comparison of the weights of perirenal fat and epididymal fat in rats across different groups and calculation of Lee’s index based on body weight and body length of rats in each group were done. And the serum concentrations of total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) levels were detected. RT-PCR and Western Blot were used to detect the levels of miR-27, PPARγ, CYP7A1 and CD36. ResultsHypoxic exercise decreased the expression levels of miR-27 in the obese rats’ liver, however, the expression level of PPARγ was gradually increased. The expression levels of miR-27 in HE group were significantly lower than N group (P<0.05). The expression levels of PPARγ mRNA in N group were significantly lower than H group (P<0.05), especially lower than HE group (P<0.01). The protein expression of PPARγ protein in N group was significantly lower than that other groups (P<0.01). The expression of lipid metabolism-related genes and proteins increased in the obese rats’ liver. The expression of CYP7A1 mRNA in N group was significantly lower than H group (P<0.05), especially lower than HE group (P<0.01). The expression of CYP7A1 protein in the obese rats’ liver in N group was extremely lower than H group and HE group (P<0.01). The protein expression of CD36 in N group was significantly lower than that in HE group (P<0.05). Hypoxia exercise improved the related physiological and biochemical indexes of lipid metabolism disorder. The perirenal fat weight of obese rats in HE group was extremely lower than N group and H group (P<0.01), and the perirenal fat weight in N group was significantly higher than H group (P<0.05). The epididymal fat weight in N group was significantly higher than H group (P<0.05), and extremely higher than HE group (P<0.01). The Lee’s index in HE group was extremely lower than N group and H group (P<0.01). The serum concentration of TC in obese rats in HE group was extremely lower than N group and H group (P<0.01). The serum concentration of TG in HE group was extremely lower than N group and H group (P<0.01). The serum concentration of LDL-C in N group was extremely higher than HE group (P<0.01). The serum concentration of HDL-C in N group was extremely lower than H group (P<0.01). ConclusionHypoxia and hypoxia exercise may negatively regulate the levels of PPARγ by inhibiting miR-27 in the obese rats’ liver, thereby affecting the expression of downstream target genes CYP7A1 and CD36, and promoting cholesterol, fatty acid oxidation and HDL-C transport in the liver, and ultimately the lipid levels in obese rats were improved. The effect of hypoxia exercise on improving blood lipid is better than simple hypoxia intervention.

Objective To isolate pathogenic bacteria from the skin of a nude mouse exhibiting squamous skin scurfs, and perform bacterial identification, traceability analysis, and pathogenicity studies to provide a new approach for the diagnosis of pathogens in nude mice with squamous skin scurfs. MethodsSkin swab samples were collected from a nude mouse exhibiting squamous skin scurfs for nucleic acid testing, bacterial isolation and culture, biochemical identification, 16S rDNA gene amplification and sequencing, and whole genome sequencing to construct a phylogenetic tree. Fifteen BALB/c nude mice were randomized into a saline-treated control group, a high-concentration group treated with 1.8×10⁸ CFU/mL of the isolated bacterial suspension, and a low-concentration group treated with 1.8×10⁷ CFU/mL of the isolated bacterial suspension. Pathogenicity was assessed by animal infection experiments and observation of histopathological changes in skin tissue using HE staining. Results The nucleic acid test for Corynebacterium bovis was negative, excluding infection by this organism. The pathogen isolated on mannitol salt agar and blood agar, combined with Gram staining, suggested a Gram-positive Staphylococcus species. The isolated strain was identified by 16S rDNA sequencing and a fully automated microbial identification system as Staphylococcus xylosus. Phylogenetic tree analysis based on whole genome sequencing showed that the strain was most closely related to an isolate from leafy vegetables in South Korea (GenBank GCA_00207825.1). In the high-concentration group, squamous skin scurfs appeared on the head, neck, and back of nude mice on the 17th day post-infection, while in the low concentration group, similar symptoms appeared on the 20th day post-infection and gradually spread to other areas. The scaling symptoms were transient, lasting for 7 days in the high-concentration group and 3 days in the low-concentration group, after which the skin returned to normal. The infection rate was 33.33% in both the high- and low-concentration groups. No significant pathological changes were observed in the skin tissues of infected mice compared to the control group, indicating marked individual differences in the pathogenicity of the strain in nude mice. Conclusion A strain of Staphylococcus xylosus was isolated from the skin of a nude mouse exhibiting squamous skin scurfs. The strain is an opportunistic pathogen that causes transient squamous skin scurfs without significant histopathological changes, and there are individual differences in the sensitivity of nude mice to this strain. These findings can provide valuable data for pathogen identification in immunodeficient or gene knockout mice.

Objective To isolate pathogenic bacteria from the skin of a nude mouse exhibiting squamous skin scurfs, and perform bacterial identification, traceability analysis, and pathogenicity studies to provide a new approach for the diagnosis of pathogens in nude mice with squamous skin scurfs. MethodsSkin swab samples were collected from a nude mouse exhibiting squamous skin scurfs for nucleic acid testing, bacterial isolation and culture, biochemical identification, 16S rDNA gene amplification and sequencing, and whole genome sequencing to construct a phylogenetic tree. Fifteen BALB/c nude mice were randomized into a saline-treated control group, a high-concentration group treated with 1.8×10⁸ CFU/mL of the isolated bacterial suspension, and a low-concentration group treated with 1.8×10⁷ CFU/mL of the isolated bacterial suspension. Pathogenicity was assessed by animal infection experiments and observation of histopathological changes in skin tissue using HE staining. Results The nucleic acid test for Corynebacterium bovis was negative, excluding infection by this organism. The pathogen isolated on mannitol salt agar and blood agar, combined with Gram staining, suggested a Gram-positive Staphylococcus species. The isolated strain was identified by 16S rDNA sequencing and a fully automated microbial identification system as Staphylococcus xylosus. Phylogenetic tree analysis based on whole genome sequencing showed that the strain was most closely related to an isolate from leafy vegetables in South Korea (GenBank GCA_00207825.1). In the high-concentration group, squamous skin scurfs appeared on the head, neck, and back of nude mice on the 17th day post-infection, while in the low concentration group, similar symptoms appeared on the 20th day post-infection and gradually spread to other areas. The scaling symptoms were transient, lasting for 7 days in the high-concentration group and 3 days in the low-concentration group, after which the skin returned to normal. The infection rate was 33.33% in both the high- and low-concentration groups. No significant pathological changes were observed in the skin tissues of infected mice compared to the control group, indicating marked individual differences in the pathogenicity of the strain in nude mice. Conclusion A strain of Staphylococcus xylosus was isolated from the skin of a nude mouse exhibiting squamous skin scurfs. The strain is an opportunistic pathogen that causes transient squamous skin scurfs without significant histopathological changes, and there are individual differences in the sensitivity of nude mice to this strain. These findings can provide valuable data for pathogen identification in immunodeficient or gene knockout mice.

The subcortical visual pathway is generally thought to be involved in dangerous information processing, such as fear processing and defensive behavior. A recent study, published in Human Brain Mapping, shows a new function of the subcortical pathway involved in the fast processing of non-emotional object perception. Rapid object processing is a critical function of visual system. Topological perception theory proposes that the initial perception of objects begins with the extraction of topological property (TP). However, the mechanism of rapid TP processing remains unclear. The researchers investigated the subcortical mechanism of TP processing with transcranial magnetic stimulation (TMS). They find that a subcortical magnocellular pathway is responsible for the early processing of TP, and this subcortical processing of TP accelerates object recognition. Based on their findings, we propose a novel training approach called subcortical magnocellular pathway training (SMPT), aimed at improving the efficiency of the subcortical M pathway to restore visual and attentional functions in disorders associated with subcortical pathway dysfunction.

To report a case of an immunocompetent young adult male patient diagnosed with intracranial Aspergillus flavus infection， and to investigate the clinical features of this disease and related experience in diagnosis and treatment.A retrospective analysis was performed for the clinical data of a patient who had the initial presentation of high fever and headache and then progressed to meningoencephalitis， and the results of cerebrospinal fluid （CSF） metagenomic next-generation sequencing （mNGS） and treatment outcomes were summarized.The patient had an acute onset， with no response to empirical anti-infective therapy in the incipient stage， and then he gradually developed disturbance of consciousness and meningeal irritation sign. CSF analysis showed inflammatory changes， while conventional pathogen tests yielded negative results， and mNGS detected 27 specific sequences of Aspergillus flavus. The symptoms of the patient was significantly improved after antifungal therapy with voriconazole， with no recurrence after follow-up for 3 months.For unexplained central nervous system infections， especially those with negative results from conventional tests， mNGS can improve the detection rate of rare pathogens（e.g.，Aspergillus flavus）. Early diagnosis and targeted antifungal therapy are crucial for improving prognosis. This case highlights that invasive fungal infections should be considered even in immunocompetent individuals.
Aspergillus flavus

ObjectiveJunctophilin-2 (JPH2) is an essential structural protein that maintains junctional membrane complexes (JMCs) in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum, thereby facilitating excitation-contraction (E-C) coupling. Mutations in JPH2 have been associated with hypertrophic cardiomyopathy (HCM), but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus (MORN) repeat motifs remain incompletely understood. This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis. MethodsA recombinant N-terminal fragment of mouse JPH2 (residues1-440), encompassing the MORN repeats and an adjacent helical region, was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain. Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features. Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells. In addition, site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations, including R347C, was used to evaluate their effects on membrane interaction and subcellular localization. ResultsThe crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6 Å, revealing a compact, elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration, forming a continuous hydrophobic core stabilized by alternating aromatic residues. A C-terminal α-helix further reinforced structural integrity. Conservation analysis identified the inner groove of the MORN array as a highly conserved surface, suggesting its role as a protein-binding interface. A flexible linker segment enriched in positively charged residues, located adjacent to the MORN motifs, was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes. Functional assays demonstrated that mutation of these basic residues impaired membrane association, while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays, despite preserving the overall MORN-Helix fold in structural modeling. ConclusionThis study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2, highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions. The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis. These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.