Objective:To establish a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the fast determination of maduramicin ammonium (MAD) in rat serum.Methods:In February 2024, rat serum samples were selected and directly injected after extraction and purification with methanol: acetonitrile (1: 1), separated on a C18 chromatographic column, and gradient-eluted using 0.1% formic acid aqueous solution -0.1% formic acid methanol solution as the mobile phase. Under optimized instrument conditions, electrospray positive ion multiple reaction monitoring (MRM) mode was employed for quantification using the external standard method, followed by methodological validation of the established approach.Results:The linearity of MAD in serum was good in the concentration range of 0.5-100 μg/L, and the correlation coefficient was 0.9997. The mean recoveries of MAD from spiked samples were 86.0%-109.6%, with the relative standard deviations were less than 10%. The limit of detection was 0.23 μg/L, The limit of detection was 0.75 μg/L.Conclusion:This method is high sensitive and reliable, which is suitable for the determination of MAD in in mouse serum.

Objective:To establish a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the fast determination of maduramicin ammonium (MAD) in rat serum.Methods:In February 2024, rat serum samples were selected and directly injected after extraction and purification with methanol: acetonitrile (1: 1), separated on a C18 chromatographic column, and gradient-eluted using 0.1% formic acid aqueous solution -0.1% formic acid methanol solution as the mobile phase. Under optimized instrument conditions, electrospray positive ion multiple reaction monitoring (MRM) mode was employed for quantification using the external standard method, followed by methodological validation of the established approach.Results:The linearity of MAD in serum was good in the concentration range of 0.5-100 μg/L, and the correlation coefficient was 0.9997. The mean recoveries of MAD from spiked samples were 86.0%-109.6%, with the relative standard deviations were less than 10%. The limit of detection was 0.23 μg/L, The limit of detection was 0.75 μg/L.Conclusion:This method is high sensitive and reliable, which is suitable for the determination of MAD in in mouse serum.

Objective:To investigate the mosquito-borne viruses carried by mosquito specimens collected from Huachuan county and Huanan county in Heilongjiang province.Methods:Mosquito samples were collected locally in 2023 and processed in the laboratory. Homogenates of the mosquitoes were inoculated into cells for virus isolation, followed by molecular and bioinformatics analyses of the viral isolates.Results:In 2023, ten viral isolates were obtained from Anopheles sinensis specimens collected in Heilongjiang province, China. Among these isolates, one was identified as Culex flavivirus (CxFV), one as Menghai rhabdovirus (MRV), and eight as Nam Dinh virus (NDiV). The phylogenetic analysis showed that CxFV belongs to genotype I and is clustered with the strains isolated from Liaoning province in 2011 and Ningxia Hui autonomous Region in 2019 in the same evolutionary branch, with amino acid similarity ranging from 98.2% to 99.2% and nucleotide similarity ranging from 98.8% to 99.2%. The MRV strain belongs to the same evolutionary subclade as the strain detected in Guangdong, with both nucleotide and amino acid similarity of 98.0%. Eight NDiV isolates clustered with the South Korean isolates on the same evolutionary branch, forming an independent evolutionary sub-branch. The nucleotide similarity among these eight isolates ranged from 98.5% to 99.7%, while the amino acid similarity ranged from 98.1% to 99.7%. In comparison, when matched with other NDiV isolates from China, the nucleotide similarity of these eight isolates ranged from 94.1% to 97.8%, and the amino acid similarity ranged from 93.5% to 97.7%.Conclusions:This study represents the first isolation of CxFV, MRV, and NDiV in Heilongjiang province, China, and the findings provide fundamental data for the prevention and control of mosquito-borne viral diseases in this region.

Objective:To establish a method for the rapid detection of varicella-zoster virus (VZV) by recombinase-aid amplification (RAA) combined with Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a system.Methods:Clinical samples of suspected herpes zoster in Shandong province and Shanghai from 2023 to 2024 were collected, nucleic acids of positive samples were extracted, RAA-specific primers and crRNA (CRISPR RNA, crRNA) were designed for the conserved region of VZV, and the fluorescence intensity generated by Cas12a non-specific cleavage of single-stranded fluorescent probes was used to screen highly sensitive crRNAs and optimize the concentrations of crRNA, Cas12a and ssDNA probes. The sensitivity and reproducibility of the RAA-CRISPR/Cas12a detection method were evaluated by using synthesized plasmids and clinical samples, and the specificity of the method was evaluated by using other viral nucleic acids. The method was used to detect clinical samples by using the method and quantitative real-time PCR (qPCR) method, and the detection rate and consistency of the two method were compared.Results:The highly sensitive crRNA-4 was screened from the four crRNAs designed, and a VZV detection method for RAA-CRISPR/CAS12a based on fluorescence intensity measurement was established, which could be detected at 37℃ in 45 min, and the sensitivity of the detection could reach 10 copies/μL, a minimum clinical sample with a Ct value of 38.980 can be detected. It has high specificity and no cross-reactivity with Adenovirus 7, Herpes simplex virus type I, Herpes simplex virus type II, Coxsackieviruses A16, Cytomegalovirus, Epstein-Barr virus, Measles virus, Mumps virus, Enterovirus 71, Japanese encephalitis virus genotype 5. It has good stability, and can be successfully detected in low, medium and high concentrations of viral positive plasmids with good consistency. The detection rate of the clinically positive samples was 100%, which was completely consistent with the qPCR test result.Conclusions:RAA isothermal amplification technology combined with CRISPR-CAS12a technology was used to establish an accurate method for the detection of VZV virus, which was highly sensitive, specific, and had low requirements for experimental conditions, and could be completed within 45 min, which could provide strong technical support for the early detection of VZV.

Objective:To investigate the mosquito-borne viruses carried by mosquito specimens collected from Huachuan county and Huanan county in Heilongjiang province.Methods:Mosquito samples were collected locally in 2023 and processed in the laboratory. Homogenates of the mosquitoes were inoculated into cells for virus isolation, followed by molecular and bioinformatics analyses of the viral isolates.Results:In 2023, ten viral isolates were obtained from Anopheles sinensis specimens collected in Heilongjiang province, China. Among these isolates, one was identified as Culex flavivirus (CxFV), one as Menghai rhabdovirus (MRV), and eight as Nam Dinh virus (NDiV). The phylogenetic analysis showed that CxFV belongs to genotype I and is clustered with the strains isolated from Liaoning province in 2011 and Ningxia Hui autonomous Region in 2019 in the same evolutionary branch, with amino acid similarity ranging from 98.2% to 99.2% and nucleotide similarity ranging from 98.8% to 99.2%. The MRV strain belongs to the same evolutionary subclade as the strain detected in Guangdong, with both nucleotide and amino acid similarity of 98.0%. Eight NDiV isolates clustered with the South Korean isolates on the same evolutionary branch, forming an independent evolutionary sub-branch. The nucleotide similarity among these eight isolates ranged from 98.5% to 99.7%, while the amino acid similarity ranged from 98.1% to 99.7%. In comparison, when matched with other NDiV isolates from China, the nucleotide similarity of these eight isolates ranged from 94.1% to 97.8%, and the amino acid similarity ranged from 93.5% to 97.7%.Conclusions:This study represents the first isolation of CxFV, MRV, and NDiV in Heilongjiang province, China, and the findings provide fundamental data for the prevention and control of mosquito-borne viral diseases in this region.

Objective:To establish a method for the rapid detection of varicella-zoster virus (VZV) by recombinase-aid amplification (RAA) combined with Clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a system.Methods:Clinical samples of suspected herpes zoster in Shandong province and Shanghai from 2023 to 2024 were collected, nucleic acids of positive samples were extracted, RAA-specific primers and crRNA (CRISPR RNA, crRNA) were designed for the conserved region of VZV, and the fluorescence intensity generated by Cas12a non-specific cleavage of single-stranded fluorescent probes was used to screen highly sensitive crRNAs and optimize the concentrations of crRNA, Cas12a and ssDNA probes. The sensitivity and reproducibility of the RAA-CRISPR/Cas12a detection method were evaluated by using synthesized plasmids and clinical samples, and the specificity of the method was evaluated by using other viral nucleic acids. The method was used to detect clinical samples by using the method and quantitative real-time PCR (qPCR) method, and the detection rate and consistency of the two method were compared.Results:The highly sensitive crRNA-4 was screened from the four crRNAs designed, and a VZV detection method for RAA-CRISPR/CAS12a based on fluorescence intensity measurement was established, which could be detected at 37℃ in 45 min, and the sensitivity of the detection could reach 10 copies/μL, a minimum clinical sample with a Ct value of 38.980 can be detected. It has high specificity and no cross-reactivity with Adenovirus 7, Herpes simplex virus type I, Herpes simplex virus type II, Coxsackieviruses A16, Cytomegalovirus, Epstein-Barr virus, Measles virus, Mumps virus, Enterovirus 71, Japanese encephalitis virus genotype 5. It has good stability, and can be successfully detected in low, medium and high concentrations of viral positive plasmids with good consistency. The detection rate of the clinically positive samples was 100%, which was completely consistent with the qPCR test result.Conclusions:RAA isothermal amplification technology combined with CRISPR-CAS12a technology was used to establish an accurate method for the detection of VZV virus, which was highly sensitive, specific, and had low requirements for experimental conditions, and could be completed within 45 min, which could provide strong technical support for the early detection of VZV.

BACKGROUND:Numerous scholars have previously researched certain greater tuberosity fractures and the procedures used to treat them.Few researchers,however,have studied the comminuted split fracture of the greater tuberosity of the humerus(Liu-Gang type IV)with rotator cuff tear in great detail. OBJECTIVE:To compare the clinical therapeutic effect of open repair position modified calcaneal plate combined with suture anchors and proximal humeral internal locking system(PHILOS)plate in the treatment of comminuted fracture of split-type greater tuberosity of humerus combined with rotator cuff tears(Liu-Gang type IV). METHODS:Case data of 30 patients with comminuted fracture of split-type greater tuberosity of humerus combined with rotator cuff tears(Liu-Gang type IV)from May 2012 to May 2022 were retrospectively analyzed.They were divided into the modified calcaneal plate combined with suture anchor group(group A)and the PHILOS with#2 Johnson group(group B),with 15 cases in each group.Intraoperative blood loss,surgical time,and incision length of all patients were recorded.Pain visual analog scale score,Constant-Murley score,as well as shoulder joint abduction,forward flexion,external rotation,and dorsal expansion activities during the last follow-up(>1 year)were evaluated. RESULTS AND CONCLUSION:(1)The surgical incision length and operation time were shorter,and blood loss was less in group A than those in group B(P<0.05).(2)No significant difference in visual analog scale score and Constant-Murley score was detected between the two groups(P>0.05).(3)During the last follow-up,forward flexion in group A was better than that in group B(P<0.05).No significant difference in abduction,external rotation,and dorsal expansion was determined between group A and group B(P>0.05).(4)In terms of complications,there was 1 case of shoulder joint pain and discomfort in group A(7%),2 cases of subacromial impingement syndrome,2 cases of upward movement of nodules,and 2 cases of shoulder joint pain(40%)in group B.There were significant differences in complication rates between the two groups(P=0.031).(5)In summary,the modified calcaneal plate combined with suture anchors in the treatment of comminuted fracture of split-type greater tuberosity of humerus combined with rotator cuff tears(Liu-Gang type IV)could better restore the forward flexion function of the shoulder joint and has a small incision,less blood loss,shorter operation time and fewer complications.

Background Di(2-ethylhexyl) phthalate (DEHP) is the highest consumed and the most widely used phthalic acid ester, their effects on lipid metabolism have attracted the attention of many scholars. However, the associated mechanism is still unclear. Objective To observe the effect of DEHP on lipid metabolism in rats, probe its possible mechanism, and provide a research basis for the effect of DEHP on human lipid metabolism. Methods Forty healthy male SD rats were randomly divided into 4 groups: solvent control (0 mg·kg⁻¹ DEHP), low DEHP (187 mg·kg⁻¹), medium DEHP (375 mg·kg⁻¹), and high DEHP (750 mg·kg⁻¹) groups. DEHP was administered by oral gavage for 6 d per week, consecutively 8 weeks. The rats were weighed once a week during the exposure period. At 24 h after the last exposure, the rats were anesthetized with 20% urethane and sacrificed by apical puncture. Rat livers were harvested and weighed before hematoxylin-eosin (HE) histopathological observation. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA levels of lipid metabolism-related genes Janus kinase 3 (JAK3), signal transducer and activator of transcription 5b (STAT5b), and peroxisome proliferator-activated receptor γ (PPARγ) in liver, and Western blot was used to detect the expression levels of lipid metabolism-related proteins JAK3, STAT5b, and PPARγ in liver. Results Compared with the control group, there was no significant difference in the body weight gain of the rats in each group (P>0.05). The liver organ coefficients of the DEHP exposure groups were higher than that of the control group (P<0.001), and increased with higher DEHP dosages. The level of high-density lipoprotein cholesterol (HDL-C) in serum decreased in all DEHP exposure groups (P<0.05), and the level of low-density lipoprotein cholesterol (LDL-C) in serum increased in the high DEHP group (P<0.05). The results of liver histopathological morphology showed that the hepatocytes of each DEHP group were enlarged and edematous in varying degrees, with loose stroma and irregular arrangement of cells, which were manifested as inflammatory cell infiltration and fatty degeneration of liver cells. Compared to the control group, the mRNA levels of JAK3, STAT5b, and PPARγ in liver tissues of rats in each DEHP group decreased (P<0.001). Compared to the control group, the relative expression levels of JAK3 in each DEHP group decreased (P<0.05), and the relative expression levels of STAT5b and PPARγ in the medium and high DEHP groups decreased (P<0.05). Conclusion DEHP exposure can induce abnormal lipid metabolism in rats, and the mechanism may be related to DEHP inhibiting the activation of JAK3/STAT5b/PPARγ signaling pathway.

Objective Genotypes(G)1,3,and 5 of the Japanese encephalitis virus(JEV)have been isolated in China,but the dominant genotype circulating in Chinese coastal areas remains unknown.We searched for G5 JEV-infected cases and attempted to elucidate which JEV genotype was most closely related to human Japanese encephalitis(JE)in the coastal provinces of China. Methods In this study,we collected serum specimens from patients with JE in three coastal provinces of China(Guangdong,Zhejiang,and Shandong)from 2018 to 2020 and conducted JEV cross-neutralization tests against G1,G3,and G5. Results Acute serum specimens from clinically reported JE cases were obtained for laboratory confirmation from hospitals in Shandong(92 patients),Zhejiang(192 patients),and Guangdong(77 patients),China,from 2018 to 2020.Seventy of the 361 serum specimens were laboratory-confirmed to be infected with JEV.Two cases were confirmed to be infected with G1 JEV,32 with G3 JEV,and two with G5 JEV. Conclusion G3 was the primary infection genotype among JE cases with a definite infection genotype,and the infection caused by G5 JEV was confirmed serologically in China.

Objective:Based on the specific cleavage and non-specific "trans-cleavage" activities of the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein(CRISPR/Cas13), we established a visually amplification-free rapid detection technique of 2019-nCoV nucleic acid. This technique is easily processed with a low detection limit and good specificity.Methods:According to the 2019-nCoV gene sequence, specific CRISPR RNAs were screened and designed by bioinformatics analysis, and then synthesized as universal signal-strained RNA transcription targets in vitro to establish and optimize the reaction system. Moreover, the 2019-nCoV pseudoviral nucleic acid was used as a standard substance to evaluate the detection limit. A total of 65 positive samples were collected from various 2019-nCoV variants, while 48 negative samples included other clinically common respiratory pathogens, such as influenza A virus, influenza B virus, human parainfluenza virus, Klebsiella pneumonia, etc. All samples were tested by quantitative PCR (qPCR), digital PCR, and the method established in this study. The sensitivity and specificity of the newly established method were analyzed and evaluated. Results:With the newly established technique, the detection time for 2019-nCoV nucleic acid could be minimized to 6 minutes. In addition, the detection limit was 14 copies/μl when assisted by the displaying instrument, whereas it increased to 28 copies/μl with the naked eye. This technique had a sensitivity and specificity of 98.5% (66/67) and 100% (46/46) respectively, showing no statistically significant difference compared to the gold standard qPCR( P=1). Conclusions:This study has successfully established a CRISPR/Cas13a-based visually rapid detection technique for 2019-nCoV nucleic acid. This technique offers the advantages of a simple process, convenient operation, low environmental operating requirements, a detection limit close to qPCR, and a strong potential for on-site testing applications.