1.Stability study of umbilical cord mesenchymal stem cells formulation in large-scale production
Wang-long CHU ; Tong-jing LI ; Yan SHANGGUAN ; Fang-tao HE ; Jian-fu WU ; Xiu-ping ZENG ; Tao GUO ; Qing-fang WANG ; Fen ZHANG ; Zhen-zhong ZHONG ; Xiao LIANG ; Jun-yuan HU ; Mu-yun LIU
Acta Pharmaceutica Sinica 2024;59(3):743-750
Umbilical cord mesenchymal stem cells (UC-MSCs) have been widely used in regenerative medicine, but there is limited research on the stability of UC-MSCs formulation during production. This study aims to assess the stability of the cell stock solution and intermediate product throughout the production process, as well as the final product following reconstitution, in order to offer guidance for the manufacturing process and serve as a reference for formulation reconstitution methods. Three batches of cell formulation were produced and stored under low temperature (2-8 ℃) and room temperature (20-26 ℃) during cell stock solution and intermediate product stages. The storage time intervals for cell stock solution were 0, 2, 4, and 6 h, while for intermediate products, the intervals were 0, 1, 2, and 3 h. The evaluation items included visual inspection, viable cell concentration, cell viability, cell surface markers, lymphocyte proliferation inhibition rate, and sterility. Additionally, dilution and culture stability studies were performed after reconstitution of the cell product. The reconstitution diluents included 0.9% sodium chloride injection, 0.9% sodium chloride injection + 1% human serum albumin, and 0.9% sodium chloride injection + 2% human serum albumin, with dilution ratios of 10-fold and 40-fold. The storage time intervals after dilution were 0, 1, 2, 3, and 4 h. The reconstitution culture media included DMEM medium, DMEM + 2% platelet lysate, 0.9% sodium chloride injection, and 0.9% sodium chloride injection + 1% human serum albumin, and the culture duration was 24 h. The evaluation items were viable cell concentration and cell viability. The results showed that the cell stock solution remained stable for up to 6 h under both low temperature (2-8 ℃) and room temperature (20-26 ℃) conditions, while the intermediate product remained stable for up to 3 h under the same conditions. After formulation reconstitution, using sodium chloride injection diluted with 1% or 2% human serum albumin maintained a viability of over 80% within 4 h. It was observed that different dilution factors had an impact on cell viability. After formulation reconstitution, cultivation in medium with 2% platelet lysate resulted in a cell viability of over 80% after 24 h. In conclusion, the stability of cell stock solution within 6 h and intermediate product within 3 h meets the requirements. The addition of 1% or 2% human serum albumin in the reconstitution diluent can better protect the post-reconstitution cell viability.
2.PRMT7 Regulates Adipogenic Differentiation of hBMSCs by Modulating IGF-1 Signaling
Qian GUO ; Jia QING ; Da-Zhuang LU ; Xu WANG ; Yang LI ; Hui ZHANG ; Ying-Fei ZHANG ; Yun-Song LIU ; Yong-Sheng ZHOU ; Ping ZHANG
Progress in Biochemistry and Biophysics 2024;51(6):1406-1417
ObjectiveProtein arginine methyltransferases (PRMTs) play pivotal roles in numerous cellular biological processes. However, the precise regulatory effects of PRMTs on the fate determination of mesenchymal stromal/stem cells (MSCs) remain elusive. Our previous studies have shed light on the regulatory role and molecular mechanism of PRMT5 in MSC osteogenic differentiation. This study aims to clarify the role and corresponding regulatory mechanism of PRMT7 during the adipogenic differentiation of bone marrow-derived mesenchymal stem cells (BMSCs). Methods(1) Human bone marrow-derived mesenchymal stem cells (hBMSCs) were cultured in a medium that induces adipogenesis. We used qRT-PCR and Western blot to monitor changes in PRMT7 expression during adipogenic differentiation. (2) We created a cell line with PRMT7 knocked down and assessed changes in PRMT7 expression and adipogenic capacity using Oil Red O staining, qRT-PCR and Western blot. (3) We implanted hBMSCs cell lines mixed with a collagen membrane subcutaneously into nude mice and performed Oil Red O staining to observe ectopic lipogenesis in vivo. (4) A cell line overexpressing PRMT7 was generated, and we examined changes in PRMT7 expression using qRT-PCR and Western blot. We also performed Oil Red O staining and quantitative analysis after inducing the cells in lipogenic medium. Additionally, we assessed changes in PPARγ expression. (5) We investigated changes in insulin-like growth factor 1 (IGF-1) expression in both PRMT7 knockdown and overexpressing cell lines using qRT-PCR and Western blot, to understand PRMT7’s regulatory effect on IGF-1 expression. siIGF-1 was transfected into the PRMT7 knockdown cell line to inhibit IGF-1 expression, and knockdown efficiency was confirmed. Then, we induced cells from the control and knockdown groups transfected with siIGF-1 in lipogenic medium and performed Oil Red O staining and quantitative analysis. Finally, we assessed PPARγ expression to explore IGF-1’s involvement in PRMT7’s regulation of adipogenic differentiation in hBMSCs. Results(1) During the adipogenesis process of hBMSCs, the expression level of PRMT7 was significantly reduced (P<0.01). (2) The adipogenic differentiation ability of PRMT7 knockdown group was significantly stronger than that of control group (P<0.001). (3) The ectopic adipogenic differentiation ability of PRMT7 knockdown group was significantly stronger than that of control group. (4) The adipogenic differentiation ability of the PRMT7 overexpression group was significantly weaker than that of the control group (P<0.01). (5) The expression level of IGF-1 increased after PRMT7 knockdown (P<0.000 1). The expression level of IGF-1 decreased after PRMT7 overexpression (P<0.000 1), indicating that PRMT7 regulates the expression of IGF-1. After siIGF-1 transfection, the expression level of IGF-1 in all cell lines decreased significantly (P<0.001). The ability of adipogenic differentiation of knockdown group transfected with siIGF-1 was significantly reduced (P<0.01), indicating that IGF-1 affects the regulation of PRMT7 on adipogenic differentiation of hBMSCs. ConclusionIn this investigation, our findings elucidate the inhibitory role of PRMT7 in the adipogenic differentiation of hBMSCs, as demonstrated through both in vitro cell-level experiments and in vivo subcutaneous transplantation experiments conducted in nude mice. Mechanistic exploration revealed that PRMT7’s regulatory effect on the adipogenic differentiation of hBMSCs operates via modulation of IGF-1 signaling pathway. These collective findings underscore PRMT7 as a potential therapeutic target for fatty metabolic disorders, thereby offering a novel avenue for leveraging PRMT7 and hBMSCs in the therapeutic landscape of relevant diseases.
3.Extracellular Acidification Impairs Macrophage Lipophagy Through ASIC1/RIP1 Pathway
Juan LIU ; Xiang OU ; Qing LIU ; Miao GUO ; Zi-Ping NING ; Hong-Feng GU ; Ya-Ling TANG
Progress in Biochemistry and Biophysics 2024;51(1):202-214
ObjectiveOur recent study has demonstrated that extracellular acidification promotes lipid accumulation in macrophages via the activation of acid sensing ion channel 1 (ASIC1), but the underlying mechanism remains unclear. This study aims to explore the effect of extracellular acidification on macrophage lipophagy and the underlying mechanism. MethodsRAW264.7 macrophages were incubated with 25 mg/Lox-LDL in a pH 6.5 culture medium for 24 h to build macrophage-derived foam cell models induced by extracellular acidification. Then, RAW264.7 macrophages were cultured in the acidic medium of pH 6.5 with or without PcTx-1 (ASIC1 specific blocker, 10 μg/L) or Nec-1 (RIP1 specific inhibitor, 20 μmol/L) for 24 h, intracellular lipid accumulation was observed by oil red O staining. The expressions of total ASIC1, plasma membrane ASIC1, RIP1, p-RIP1 Ser166, TFEB, p-TFEB Ser142, LC3 and p62 were measured by Western blot. The co-localization of lipids (indicated by Bodipy) with LC3II (autophagosomes) and LAMP1 (lysosomes) was analyzed by a confocal laser scanning microscopy, respectively. Morphological changes of lipophagy in the cells were observed by using transmission electron microscopy. ABCA1-mediated cholesterol efflux was determined by cholesterol fluorescence kits. ResultsCompared with pH 7.4+ox-LDL group, the intracellular lipid accumulation in the pH 6.5+ox-LDL group was significantly increased. Meanwhile, the expressions of plasma membrane ASIC1, p-RIP1 Ser166, p-TFEB Ser142, and p62 proteins were elevated significantly, while LC3II protein level and LC3II/LC3I ratio were decreased. Accordingly, compared with pH 7.4+ox-LDL group, the macrophage lipophagy of the pH 6.5+ox-LDL group was inhibited as indicated by the decreased localization of lipid droplets with LC3 and LAMP1, a decrease in the number of lipophagosomes as well as an increase in lipid droplets. Furthermore, ATP binding cassette transporter A1 (ABCA1)-dependent cholesterol efflux from the macrophages of pH 6.5+ox-LDL group reduced dramatically. However, these above effects of extracellular acidification on RAW264.7 macrophages were abolished by PcTx-1 and Nec-1, respectively. ConclusionThese findings suggest extracellular acidification promotes the phosphorylation of TFEB at Ser142 via activating ASIC1/RIP1 pathway, thereby impeding lipophagy in RAW 264.7 macrophages, and that ASIC1 may be a new potential target for preventing aberrant lipid accumulation diseases including atherosclerosis.
4.Clinical trial of brexpiprazole in the treatment of adults with acute schizophrenia
Shu-Zhe ZHOU ; Liang LI ; Dong YANG ; Jin-Guo ZHAI ; Tao JIANG ; Yu-Zhong SHI ; Bin WU ; Xiang-Ping WU ; Ke-Qing LI ; Tie-Bang LIU ; Jie LI ; Shi-You TANG ; Li-Li WANG ; Xue-Yi WANG ; Yun-Long TAN ; Qi LIU ; Uki MOTOMICHI ; Ming-Ji XIAN ; Hong-Yan ZHANG
The Chinese Journal of Clinical Pharmacology 2024;40(5):654-658
Objective To evaluate the efficacy and safety of brexpiprazole in treating acute schizophrenia.Methods Patients with schizophrenia were randomly divided into treatment group and control group.The treatment group was given brexpiprozole 2-4 mg·d-1 orally and the control group was given aripiprazole 10-20 mg·d-1orally,both were treated for 6 weeks.Clinical efficacy of the two groups,the response rate at endpoint,the changes from baseline to endpoint of Positive and Negative Syndrome Scale(PANSS),Clinical Global Impression-Improvement(CGI-S),Personal and Social Performance scale(PSP),PANSS Positive syndrome subscale,PANSS negative syndrome subscale were compared.The incidence of treatment-related adverse events in two groups were compared.Results There were 184 patients in treatment group and 186 patients in control group.After treatment,the response rates of treatment group and control group were 79.50%(140 cases/184 cases)and 82.40%(150 cases/186 cases),the scores of CGI-I of treatment group and control group were(2.00±1.20)and(1.90±1.01),with no significant difference(all P>0.05).From baseline to Week 6,the mean change of PANSS total score wese(-30.70±16.96)points in treatment group and(-32.20±17.00)points in control group,with no significant difference(P>0.05).The changes of CGI-S scores in treatment group and control group were(-2.00±1.27)and(-1.90±1.22)points,PSP scores were(18.80±14.77)and(19.20±14.55)points,PANSS positive syndrome scores were(-10.30±5.93)and(-10.80±5.81)points,PANSS negative syndrome scores were(-6.80±5.98)and(-7.30±5.15)points,with no significant difference(P>0.05).There was no significant difference in the incidence of treatment-related adverse events between the two group(69.00%vs.64.50%,P>0.05).Conclusion The non-inferiority of Brexpiprazole to aripiprazole was established,with comparable efficacy and acceptability.
5.National bloodstream infection bacterial resistance surveillance report (2022) : Gram-negative bacteria
Zhiying LIU ; Yunbo CHEN ; Jinru JI ; Chaoqun YING ; Qing YANG ; Haishen KONG ; Haifeng MAO ; Hui DING ; Pengpeng TIAN ; Jiangqin SONG ; Yongyun LIU ; Jiliang WANG ; Yan JIN ; Yuanyuan DAI ; Yizheng ZHOU ; Yan GENG ; Fenghong CHEN ; Lu WANG ; Yanyan LI ; Dan LIU ; Peng ZHANG ; Junmin CAO ; Xiaoyan LI ; Dijing SONG ; Xinhua QIANG ; Yanhong LI ; Qiuying ZHANG ; Guolin LIAO ; Ying HUANG ; Baohua ZHANG ; Liang GUO ; Aiyun LI ; Haiquan KANG ; Donghong HUANG ; Sijin MAN ; Zhuo LI ; Youdong YIN ; Kunpeng LIANG ; Haixin DONG ; Donghua LIU ; Hongyun XU ; Yinqiao DONG ; Rong XU ; Lin ZHENG ; Shuyan HU ; Jian LI ; Qiang LIU ; Liang LUAN ; Jilu SHEN ; Lixia ZHANG ; Bo QUAN ; Xiaoping YAN ; Xiaoyan QI ; Dengyan QIAO ; Weiping LIU ; Xiusan XIA ; Ling MENG ; Jinhua LIANG ; Ping SHEN ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2024;17(1):42-57
Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-negative bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-negative bacteria from blood cultures in member hospitals of national bloodstream infection Bacterial Resistant Investigation Collaborative System(BRICS)were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute(CLSI). WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:During the study period,9 035 strains of Gram-negative bacteria were collected from 51 hospitals,of which 7 895(87.4%)were Enterobacteriaceae and 1 140(12.6%)were non-fermenting bacteria. The top 5 bacterial species were Escherichia coli( n=4 510,49.9%), Klebsiella pneumoniae( n=2 340,25.9%), Pseudomonas aeruginosa( n=534,5.9%), Acinetobacter baumannii complex( n=405,4.5%)and Enterobacter cloacae( n=327,3.6%). The ESBLs-producing rates in Escherichia coli, Klebsiella pneumoniae and Proteus spp. were 47.1%(2 095/4 452),21.0%(427/2 033)and 41.1%(58/141),respectively. The prevalence of carbapenem-resistant Escherichia coli(CREC)and carbapenem-resistant Klebsiella pneumoniae(CRKP)were 1.3%(58/4 510)and 13.1%(307/2 340);62.1%(36/58)and 9.8%(30/307)of CREC and CRKP were resistant to ceftazidime/avibactam combination,respectively. The prevalence of carbapenem-resistant Acinetobacter baumannii(CRAB)complex was 59.5%(241/405),while less than 5% of Acinetobacter baumannii complex was resistant to tigecycline and polymyxin B. The prevalence of carbapenem-resistant Pseudomonas aeruginosa(CRPA)was 18.4%(98/534). There were differences in the composition ratio of Gram-negative bacteria in bloodstream infections and the prevalence of main Gram-negative bacteria resistance among different regions,with statistically significant differences in the prevalence of CRKP and CRPA( χ2=20.489 and 20.252, P<0.001). The prevalence of CREC,CRKP,CRPA,CRAB,ESBLs-producing Escherichia coli and Klebsiella pneumoniae were higher in provinicial hospitals than those in municipal hospitals( χ2=11.953,81.183,10.404,5.915,12.415 and 6.459, P<0.01 or <0.05),while the prevalence of CRPA was higher in economically developed regions(per capita GDP ≥ 92 059 Yuan)than that in economically less-developed regions(per capita GDP <92 059 Yuan)( χ2=6.240, P=0.012). Conclusions:The proportion of Gram-negative bacteria in bloodstream infections shows an increasing trend,and Escherichia coli is ranked in the top,while the trend of CRKP decreases continuously with time. Decreasing trends are noted in ESBLs-producing Escherichia coli and Klebsiella pneumoniae. Low prevalence of carbapenem resistance in Escherichia coli and high prevalence in CRAB complex have been observed. The composition ratio and antibacterial spectrum of bloodstream infections in different regions of China are slightly different,and the proportion of main drug resistant bacteria in provincial hospitals is higher than those in municipal hospitals.
6.Application of the OmniLogTM microbial identification system in the detection of the host spectrum for wild-type plague phage in Qinghai Plateau
Cun-Xiang LI ; Zhi-Zhen QI ; Qing-Wen ZHANG ; Hai-Hong ZHAO ; Long MA ; Pei-Song YOU ; Jian-Guo YANG ; Hai-Sheng WU ; Jian-Ping FENG
Chinese Journal of Zoonoses 2024;40(1):21-25
The growth of three plague phages from Qinghai Plateau in two Yersinia pestis strains(plague vaccine strains EV76 and 614F)and four non-Yersinia pestis strains(Yersinia pseudotuberculosis PTB3,PTB5,Escherichia coli V517,and Yersinia enterocolitica 52302-2)were detected through a micromethod based on the OmniLogTM microbial identification system and by the drop method,to provide a scientific basis for future ecological studies and classification based on the host range.For plague vaccine strains EV76 and 614F,successful phage infection and subsequent phage growth were observed in the host bacte-rium.Diminished bacterial growth and respiration and a concomitant decrease in color were observed with the OmniLogTM mi-crobial identification system at 33 ℃ for 48 h.Yersinia pseudotuberculosis PTB5 was sensitive to Yersinia pestis phage 476,but Yersinia pseudotuberculosis PST5 was insensitive to phage 087 and 072204.Three strains of non-Yersinia pestis(Yersinia pseudotuberculosis PTB3,Escherichia coli V517,and Yersinia enterocolitica 52302-2)were insensitive to Yersinia pestis pha-ges 087,072204,and 476 showed similar growth curves.The growth of phages 476 and 087,as determined with the drop method,in two Yersinia pestis strains(plague vaccine strains EV76 and 614F)and four non-Yersinia pestis strains(Yersinia pseudotuberculosis PTB3,Escherichia coli V517,and Yersin-ia enterocolitica 52302-2)showed the same results at 37 ℃,on the basis of comparisons with the OmniLogTM microbial i-dentification system;in contrast,phages 072204 did not show plaques on solid medium at 37 ℃ with plague vaccine strains EV76 and 614F.Determination based on the OmniLogTM detection system can be used as an alternative to the traditional determination of the host range,thus providing favorable application val-ue for determining the interaction between the phage and host bacteria.
7.National bloodstream infection bacterial resistance surveillance report(2022): Gram-positive bacteria
Chaoqun YING ; Yunbo CHEN ; Jinru JI ; Zhiying LIU ; Qing YANG ; Haishen KONG ; Haifeng MAO ; Hui DING ; Pengpeng TIAN ; Jiangqin SONG ; Yongyun LIU ; Jiliang WANG ; Yan JIN ; Yuanyuan DAI ; Yizheng ZHOU ; Yan GENG ; Fenghong CHEN ; Lu WANG ; Yanyan LI ; Dan LIU ; Peng ZHANG ; Junmin CAO ; Xiaoyan LI ; Dijing SONG ; Xinhua QIANG ; Yanhong LI ; Qiuying ZHANG ; Guolin LIAO ; Ying HUANG ; Baohua ZHANG ; Liang GUO ; Aiyun LI ; Haiquan KANG ; Donghong HUANG ; Sijin MAN ; Zhuo LI ; Youdong YIN ; Kunpeng LIANG ; Haixin DONG ; Donghua LIU ; Hongyun XU ; Yinqiao DONG ; Rong XU ; Lin ZHENG ; Shuyan HU ; Jian LI ; Qiang LIU ; Liang LUAN ; Jilu SHEN ; Lixia ZHANG ; Bo QUAN ; Xiaoping YAN ; Xiaoyan QI ; Dengyan QIAO ; Weiping LIU ; Xiusan XIA ; Ling MENG ; Jinhua LIANG ; Ping SHEN ; Yonghong XIAO
Chinese Journal of Clinical Infectious Diseases 2024;17(2):99-112
Objective:To report the results of national surveillance on the distribution and antimicrobial resistance profile of clinical Gram-positive bacteria isolates from bloodstream infections in China in 2022.Methods:The clinical isolates of Gram-positive bacteria from blood cultures in member hospitals of National Bloodstream Infection Bacterial Resistant Investigation Collaborative System(BRICS)were collected during January 2022 to December 2022. Antibiotic susceptibility tests were conducted by agar dilution or broth dilution methods recommended by Clinical and Laboratory Standards Institute(CLSI). WHONET 5.6 and SPSS 25.0 software were used to analyze the data.Results:A total of 3 163 strains of Gram-positive pathogens were collected from 51 member units,and the top five bacteria were Staphylococcus aureus( n=1 147,36.3%),coagulase-negative Staphylococci( n=928,29.3%), Enterococcus faecalis( n=369,11.7%), Enterococcus faecium( n=296,9.4%)and alpha-hemolyticus Streptococci( n=192,6.1%). The detection rates of methicillin-resistant Staphylococcus aureus(MRSA)and methicillin-resistant coagulase-negative Staphylococci(MRCNS)were 26.4%(303/1 147)and 66.7%(619/928),respectively. No glycopeptide and daptomycin-resistant Staphylococci were detected. The sensitivity rates of Staphylococcus aureus to cefpirome,rifampin,compound sulfamethoxazole,linezolid,minocycline and tigecycline were all >95.0%. Enterococcus faecium was more prevalent than Enterococcus faecalis. The resistance rates of Enterococcus faecium to vancomycin and teicoplanin were both 0.5%(2/369),and no vancomycin-resistant Enterococcus faecium was detected. The detection rate of MRSA in southern China was significantly lower than that in other regions( χ2=14.578, P=0.002),while the detection rate of MRCNS in northern China was significantly higher than that in other regions( χ2=15.195, P=0.002). The detection rates of MRSA and MRCNS in provincial hospitals were higher than those in municipal hospitals( χ2=13.519 and 12.136, P<0.001). The detection rates of MRSA and MRCNS in economically more advanced regions(per capita GDP≥92 059 Yuan in 2022)were higher than those in economically less advanced regions(per capita GDP<92 059 Yuan)( χ2=9.969 and 7.606, P=0.002和0.006). Conclusions:Among the Gram-positive pathogens causing bloodstream infections in China, Staphylococci is the most common while the MRSA incidence decreases continuously with time;the detection rate of Enterococcus faecium exceeds that of Enterococcus faecalis. The overall prevalence of vancomycin-resistant Enterococci is still at a low level. The composition ratio of Gram-positive pathogens and resistant profiles varies slightly across regions of China,with the prevalence of MRSA and MRCNS being more pronounced in provincial hospitals and areas with a per capita GDP≥92 059 yuan.
8.Investigation on potential subtyping and progression biomarkers of nephrotic syndrome based on LC-MS metabolomics technology
Qing-yu ZHANG ; Qian WANG ; Xing-xing ZHANG ; Song-jia GUO ; Ai-ping LI
Acta Pharmaceutica Sinica 2024;59(6):1779-1786
Nephrotic syndrome (NS) has a variety of classifications, pathogenesis and pathological types. Clinical diagnosis primarily relies on serum biochemistry, while the specific classification necessitates renal puncture for biopsy, which is hindered by poor patient compliance. Therefore, it is of great significance for clinical diagnosis to find a non-invasive and rapid method to reflect the classification and progression of nephrotic syndrome. In this study, LC-MS metabolomics combined with receiver operating characteristic (ROC) and multiple linear regression analysis was used to screen and identify potential biomarkers capable of reflecting the typing and progression of nephrotic syndrome. According to the statistical parameters VIP>1,
9.Isolation, chiral separation and absolute configuration determination of lignanoids from an aqueous extract of the Angelica sinensis root head
Xiao-yi ZHANG ; Zhao XIA ; Xiao-qiang LEI ; Wei-ping LI ; Rong LIU ; Qing-lan GUO ; Jian-gong SHI
Acta Pharmaceutica Sinica 2024;59(7):2077-2086
From an aqueous extract of the
10.Application of Protease-Hydrogen Peroxide Digestion Method in Forensic Diatom Examination
Wen-Qing GUO ; Min CHEN ; Ao MA ; Ping HUANG ; Ji ZHANG
Journal of Forensic Medicine 2024;40(4):317-323
Objective To propose a novel forensic diatom examination method,namely the protease-hydrogen peroxide(PHP)digestion method,and to explore its potential application in forensic prac-tice.Methods The PHP digestion method was applied to process lung tissues and compared with the traditional nitric acid digestion method in terms of diatom quantity,recovery rate,proportion of diatom fragments,and recovery efficiency of different diatom genera.Results The PHP digestion method showed higher diatom quantity,recovery rate,and proportion of diatom fragments compared to the tra-ditional nitric acid digestion method with statistical significance.The average diatom recovery rate was as high as 93.95%.In the lung tissues digested with nitric acid,there were 65 Achnanthes,36 NitzschiaⅠ,22 Nitzschia Ⅱ,20 Diploneis and 8 Cymbella,showing significantly lower recovery rates compared to water samples which had 154 Achnanthes,44 Nitzschia Ⅰ,45 Nitzschia Ⅱ,33 Diploneis and 23 Cym-bella.However,with the PHP digestion method,only Nitzschia Ⅱ showed a lower recovery rate com-pared to water samples(P<0.05).At the same time,the diatom recovery stability of the PHP diges-tion method was higher than that of the nitric acid digestion method.Conclusion The PHP digestion method is superior to the traditional nitric acid digestion method in the lung tissue diatom extraction efficiency.Additionally,it holds significant advantages in safety,environmental protection,and other as-pects.It is expected to be applied in forensic drowning identification.

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