1.Preparation and Evaluation of Clinical-Grade Human Umbilical Cord-Derived Mesenchymal Stem Cells with High Expression of Hematopoietic Supporting Factors.
Jie TANG ; Pei-Lin LI ; Xiao-Yu ZHANG ; Xiao-Tong LI ; Fu-Hao YU ; Jia-Yi TIAN ; Run-Xiang XU ; Bo-Feng YIN ; Li DING ; Heng ZHU
Journal of Experimental Hematology 2025;33(3):892-898
OBJECTIVE:
To prepare clinical-grade human umbilical cord-derived mesenchymal stem cells (hUC-MSC) with high expression of hematopoietic supporting factors and evaluate their stem cell characteristics.
METHODS:
Fetal umbilical cord tissues were collected from healthy postpartum women during full-term cesarean section. Wharton's jelly was mechanically separated and hUC-MSCs were obtained by explant culture method and enzyme digestion method in an animal serum-free culture system with addition of human platelet lysate. The phenotypic characteristics of hUC-MSCs obtained by two methods were detected by flow cytometry. The differences in proliferation ability between the two groups of hUC-MSCs were identified through CCK-8 assay and colony forming unit-fibroblast (CFU-F) assay. The differences in multilineage differentiation potential between the two groups of hUC-MSCs were identified through induction of adipogenic, osteogenic, and chondrogenic differentiation. The mRNA expression levels of hematopoietic supporting factors such as SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in the two groups of hUC-MSCs were identified by real-time fluorescence quantiative PCR(RT-qPCR).
RESULTS:
The results of flow cytometry showed that hUC-MSCs obtained by the two methods both expressed high levels of CD73, CD90 and CD105, while lowly expressed CD31, CD45 and HLA-DR. The results of CCK-8 and CFU-F assay showed that the proliferation ability of hUC-MSCs obtained by explant culture method was better than those obtained by enzyme digestion method. The results of the triple lineage differentiation experiment showed that there was no significant difference in multilineage differentiation potential between the two grous of hUC-MSCs. The results of RT-qPCR showed that the mRNA expression levels of hematopoietic supporting factors SCF, IL-3, CXCL12, VCAM1 and ANGPT1 in hUC-MSCs obtained by explant cultrue method were higher than those obtained by enzyme digestion method.
CONCLUSION
Clinical-grade hUC-MSCs with high expression levels of hematopoietic supporting factors were successfully cultured in an animal serum-free culture system.
Humans
;
Mesenchymal Stem Cells/metabolism*
;
Umbilical Cord/cytology*
;
Cell Differentiation
;
Female
;
Cell Proliferation
;
Cells, Cultured
;
Chemokine CXCL12/metabolism*
;
Angiopoietin-1/metabolism*
;
Vascular Cell Adhesion Molecule-1/metabolism*
;
Stem Cell Factor/metabolism*
;
Flow Cytometry
;
Pregnancy
2.Advantages of Chinese Medicines for Diabetic Retinopathy and Mechanisms: Focused on Inflammation and Oxidative Stress.
Li-Shuo DONG ; Chong-Xiang XUE ; Jia-Qi GAO ; Yue HU ; Ze-Zheng KANG ; A-Ru SUN ; Jia-Rui LI ; Xiao-Lin TONG ; Xiu-Ge WANG ; Xiu-Yang LI
Chinese journal of integrative medicine 2025;31(11):1046-1055
3.Effect of lncRNA KCNQ1OT1 on oxygen glucose deprivation/reoxygenation-induced microglia injury through regulating the miR-145-5p/ROCK1 axis
Lin LI ; Xiang-nan LI ; Song-tao YANG ; Yun-he ZHANG ; Tong CHEN ; Ai-jun FU
Journal of Regional Anatomy and Operative Surgery 2025;34(6):478-483
Objective To investigate the effect of long non-coding RNA(lncRNA)potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1(KCNQ1OT1)on oxidative glucose deprivation/reoxygenation(OGD/R)-induced microglia injury through regulating the miR-145-5p/Rho-associated coiled-coil forming protein kinase 1(ROCK1)axis.Methods Microglia N9 were divided into the control group(normal culture),the OGD/R group(OGD/R-induced injury),the sh-NC group(transfected with sh-NC after OGD/R-induced injury),the sh-KCNQ1OT1 group(transfected with sh-KCNQ1OT1 after OGD/R-induced injury),the sh-KCNQ1OT1+inhibitor NC group(co-transfected with sh-KCNQ1OT1 and inhibitor NC after OGD/R-induced injury),and the sh-KCNQ1OT1+miR-145-5p inhibitor group(co-transfected with sh-KCNQ1OT1 and miR-145-5p inhibitor after OGD/R-induced injury).RT-qPCR was applied to detect the expression of lncRNA KCNQ1OT1,miR-145-5p,and ROCK1 mRNA in cells.The expression of ROCK1 protein was detected by Western blot.CCK-8 was applied to detect the cell proliferation.Flow cytometry was applied to detect cell apoptosis.ELISA was applied to detect the levels of interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),and interleukin-6(IL-6)in cells.The action sites of miR-145-5p with lncRNA KCNQ1OT1 and ROCK1 were predicted by bioinformatics website,and their targeting relationships were verified by dual-luciferase reporter assay.Results Compared with the control group,the expression of lncRNA KCNQ1OT1,the expression of ROCK1 mRNA and protein,the apoptosis rate,and the levels of IL-6,TNF-α,and IL-1β in cells were all increased,and the level of miR-145-5p and cell survival rate were all decreased in the OGD/R group(P<0.05).Compared with the OGD/R group and the sh-NC group,the expression of lncRNA KCNQ1OT1,the expression of ROCK1 mRNA and protein,the apoptosis rate,and the levels of IL-6,TNF-α,and IL-1β in cells were all decreased,and the level of miR-145-5p and cell survival rate were all increased in the sh-KCNQ1OT1 group,with significant differences(P<0.05).Compared with the sh-KCNQ1OT1+inhibitor NC group,the expression of ROCK1 mRNA and protein,the apoptosis rate,and the levels of IL-6,TNF-α,and IL-1β in cells were all increased,and the expression of miR-145-5p and cell survival rate were all decreased in the sh-KCNQ1OT1+miR-145-5p inhibitor group,with significant differences(P<0.05).Bioinformatics website showed that miR-145-5p had targeted action sites with lncRNA KCNQ1OT1 and ROCK1,and dual-luciferase reporter assay confirmed that miR-145-5p had targeting relationships with lncRNA KCNQ1OT1 and ROCK1(P<0.05).Conclusion Silencing lncRNA KCNQ1OT1 can alleviate OGD/R-induced microglia injury via upregulating the expression of miR-145-5p and targeting the down-regulation of ROCK1 expression.
4.Development and reliability and validity of the Questionnaire on Pain Nursing Competency evaluation of nursing students
Ke NI ; Yingge TONG ; Donghua LIU ; Xiang PAN ; Lingling LUO ; Xiaoyan LI ; Miaoling WANG ; Ying LIN ; Yixuan LI ; Jinwei QIAN ; Lihui GU
Chinese Journal of Practical Nursing 2025;41(8):569-576
Objective:To develop and validate the Pain nursing Competency Evaluation Questionnaire for Nursing Students to provide an effective tool for measuring the pain management competency of nursing students in China.Methods:The questionnaire was constructed through literature review, semi-structured interviews, focus group discussions, Delphi expert consultation, and a pre-survey. From September 2023 to January 2024, a convenience sampling method was used to select 250 nursing students from Hangzhou Normal University and Lishui University in Zhejiang Province for the survey. Reliability and validity of the developed questionnaire were tested. A random sample of 30 nursing students was selected for retesting after two weeks.Results:A total of 10 female experts were consulted through correspondence. The Pain Care Competency Evaluation Questionnaire for nursing students consists of 36 items. Through exploratory factor analysis, five common factors were extracted: pain health education, comprehensive pain assessment, pain screening and assessment, analgesic interventions, and analgesic side effects nursing, which together explained 61.695% of the variance. The content validity of the questionnaire was 0.96, and the item-level content validity index ranged from 0.900 to 1.000. The overall Cronbach′s α coefficient was 0.924, and the Cronbach′s α coefficients for the five dimensions ranged from 0.856 to 0.915. The test-retest reliability was 0.831. Conclusions:The Pain Care Competency Evaluation Questionnaire for nursing students developed in this study has good reliability and validity. It can be used as a tool to assess nursing students′ competency in pain care and provides a reference for the design and optimization of pain care courses and clinical practice programs for nursing students in undergraduate institutions.
5.Effect of lncRNA KCNQ1OT1 on oxygen glucose deprivation/reoxygenation-induced microglia injury through regulating the miR-145-5p/ROCK1 axis
Lin LI ; Xiang-nan LI ; Song-tao YANG ; Yun-he ZHANG ; Tong CHEN ; Ai-jun FU
Journal of Regional Anatomy and Operative Surgery 2025;34(6):478-483
Objective To investigate the effect of long non-coding RNA(lncRNA)potassium voltage-gated channel subfamily Q member 1 overlapping transcript 1(KCNQ1OT1)on oxidative glucose deprivation/reoxygenation(OGD/R)-induced microglia injury through regulating the miR-145-5p/Rho-associated coiled-coil forming protein kinase 1(ROCK1)axis.Methods Microglia N9 were divided into the control group(normal culture),the OGD/R group(OGD/R-induced injury),the sh-NC group(transfected with sh-NC after OGD/R-induced injury),the sh-KCNQ1OT1 group(transfected with sh-KCNQ1OT1 after OGD/R-induced injury),the sh-KCNQ1OT1+inhibitor NC group(co-transfected with sh-KCNQ1OT1 and inhibitor NC after OGD/R-induced injury),and the sh-KCNQ1OT1+miR-145-5p inhibitor group(co-transfected with sh-KCNQ1OT1 and miR-145-5p inhibitor after OGD/R-induced injury).RT-qPCR was applied to detect the expression of lncRNA KCNQ1OT1,miR-145-5p,and ROCK1 mRNA in cells.The expression of ROCK1 protein was detected by Western blot.CCK-8 was applied to detect the cell proliferation.Flow cytometry was applied to detect cell apoptosis.ELISA was applied to detect the levels of interleukin-1β(IL-1β),tumor necrosis factor-α(TNF-α),and interleukin-6(IL-6)in cells.The action sites of miR-145-5p with lncRNA KCNQ1OT1 and ROCK1 were predicted by bioinformatics website,and their targeting relationships were verified by dual-luciferase reporter assay.Results Compared with the control group,the expression of lncRNA KCNQ1OT1,the expression of ROCK1 mRNA and protein,the apoptosis rate,and the levels of IL-6,TNF-α,and IL-1β in cells were all increased,and the level of miR-145-5p and cell survival rate were all decreased in the OGD/R group(P<0.05).Compared with the OGD/R group and the sh-NC group,the expression of lncRNA KCNQ1OT1,the expression of ROCK1 mRNA and protein,the apoptosis rate,and the levels of IL-6,TNF-α,and IL-1β in cells were all decreased,and the level of miR-145-5p and cell survival rate were all increased in the sh-KCNQ1OT1 group,with significant differences(P<0.05).Compared with the sh-KCNQ1OT1+inhibitor NC group,the expression of ROCK1 mRNA and protein,the apoptosis rate,and the levels of IL-6,TNF-α,and IL-1β in cells were all increased,and the expression of miR-145-5p and cell survival rate were all decreased in the sh-KCNQ1OT1+miR-145-5p inhibitor group,with significant differences(P<0.05).Bioinformatics website showed that miR-145-5p had targeted action sites with lncRNA KCNQ1OT1 and ROCK1,and dual-luciferase reporter assay confirmed that miR-145-5p had targeting relationships with lncRNA KCNQ1OT1 and ROCK1(P<0.05).Conclusion Silencing lncRNA KCNQ1OT1 can alleviate OGD/R-induced microglia injury via upregulating the expression of miR-145-5p and targeting the down-regulation of ROCK1 expression.
6.Development and reliability and validity of the Questionnaire on Pain Nursing Competency evaluation of nursing students
Ke NI ; Yingge TONG ; Donghua LIU ; Xiang PAN ; Lingling LUO ; Xiaoyan LI ; Miaoling WANG ; Ying LIN ; Yixuan LI ; Jinwei QIAN ; Lihui GU
Chinese Journal of Practical Nursing 2025;41(8):569-576
Objective:To develop and validate the Pain nursing Competency Evaluation Questionnaire for Nursing Students to provide an effective tool for measuring the pain management competency of nursing students in China.Methods:The questionnaire was constructed through literature review, semi-structured interviews, focus group discussions, Delphi expert consultation, and a pre-survey. From September 2023 to January 2024, a convenience sampling method was used to select 250 nursing students from Hangzhou Normal University and Lishui University in Zhejiang Province for the survey. Reliability and validity of the developed questionnaire were tested. A random sample of 30 nursing students was selected for retesting after two weeks.Results:A total of 10 female experts were consulted through correspondence. The Pain Care Competency Evaluation Questionnaire for nursing students consists of 36 items. Through exploratory factor analysis, five common factors were extracted: pain health education, comprehensive pain assessment, pain screening and assessment, analgesic interventions, and analgesic side effects nursing, which together explained 61.695% of the variance. The content validity of the questionnaire was 0.96, and the item-level content validity index ranged from 0.900 to 1.000. The overall Cronbach′s α coefficient was 0.924, and the Cronbach′s α coefficients for the five dimensions ranged from 0.856 to 0.915. The test-retest reliability was 0.831. Conclusions:The Pain Care Competency Evaluation Questionnaire for nursing students developed in this study has good reliability and validity. It can be used as a tool to assess nursing students′ competency in pain care and provides a reference for the design and optimization of pain care courses and clinical practice programs for nursing students in undergraduate institutions.
7.The Enhancing Effects and Underlying Mechanism of Ionizing Radiation on Adipogenic Differentiation of Mesenchymal Stem Cells via Regulating Oxidative Stress Pathway
Fu-Hao YU ; Bo-Feng YIN ; Pei-Lin LI ; Xiao-Tong LI ; Jia-Yi TIAN ; Run-Xiang XU ; Jie TANG ; Xiao-Yu ZHANG ; Wen-Jing ZHANG ; Heng ZHU ; Li DING
Journal of Experimental Hematology 2025;33(1):246-254
Objective:To investigate the effects and underlying mechanism of ionizing radiation on the adipogenic of mesenchymal stem cells(MSCs).Methods:Mouse MSCs were cultured in vitro and treated with 2 Gy and 6 Gy radiation with 60Co,and the radiation dose rate was 0.98 Gy/min.Bulk RNA-seq was performed on control and irradiated MSCs.The changes of adipogenic differentiation and oxidative stress pathways of MSC were revealed by bioinformatics analysis.Oil Red O staining was used to detect the adipogenic differentiation ability of MSCs in vitro,and real-time fluorescence quantitative PCR(qPCR)was used to detect the expression differences of key regulatory factors Cebpa,Lpl and Pparg after radiation treatment.At the same time,qPCR and Western blot were used to detect the effect of inhibition of Nrf2,a key factor of antioxidant stress pathway,on the expression of key regulatory factors of adipogenesis.Moreover,the species conservation of the irradiation response of human bone marrow MSCs and mouse MSC was determined by qPCR.Results:Bulk RNA-seq suggested that ionizing radiation promotes adipogenic differentiation of MSCs and up-regulation of oxidative stress-related genes and pathways.The results of Oil Red O staining and qPCR showed that ionizing radiation promoted the adipogenesis of MSCs,with high expression of Cebpa,Lpl and Pparg,as well as oxidative stress-related gene Nrf2.Nrf2 pathway inhibitors could further enhance the adipogenesis of MSCs in bone marrow after radiation.Notably,the similar regulation of oxidative pathways and enhanced adipogenesis post irradiation were observed in human bone marrow MSCs.In addition,irradiation exposure led to up-regulated mRNA expression of interleukin-6 and down-regulated mRNA expression of colony stimulating factor 2 in human bone marrow MSCs.Conclusion:Ionizing radiation promotes adipogenesis of MSCs in mice,and oxidative stress pathway participates in this effect,blocking Nrf2 further promotes the adipogenesis of MSCs.Additionally,irradiation activates oxidative pathways and promotes adipogenic differentiation of human bone marrow MSCs.
8.Establishment and Application of an in Vitro Cellular Model of Adipogenic Differentiation of Bone Marrow Mesenchymal Stem Cells with Serum Injury in aGVHD Mouse
Run-Xiang XU ; Pei-Lin LI ; Jia-Yi TIAN ; Jie TANG ; Bo-Feng YIN ; Fu-Hao YU ; Fei-Yan WANG ; Xiao-Tong LI ; Xiao-Yu ZHANG ; Wen-Rong XIA ; Heng ZHU ; Li DING
Journal of Experimental Hematology 2025;33(1):255-261
Objective:To establish an in vitro cell model simulating acute graft-versus-host disease(aGVHD)bone marrow microenvironment injury with the advantage of mouse serum of aGVHD model and explore the effect of serum of aGVHD mouse on the adipogenic differentiation ability of mesenchymal stem cells(MSCs).Methods:The 6-8-week-old C57BL/6N female mice and BALB/c female mice were used as the donor and recipient mice of the aGVHD model,respectively.Bone marrow transplantation(BMT)mouse model(n=20)was established by being injected with bone marrow cells(1 × 10'per mouse)from donor mice within 4-6 hours after receiving a lethal dose(8.0 Gy,72.76 cGy/min)of y ray general irradiation.A mouse model of aGVHD(n=20)was established by infusing a total of 0.4 ml of a mixture of donor mouse-derived bone marrow cells(1 × 107 per mouse)and spleen lymphocytes(2 × 106 per mouse).The blood was removed from the eyeballs and the mouse serum was aspirated on the 7th day after modeling.Bone marrow-derived MSCs were isolated from 1-week-old C57BL/6N male mice and incubated with 2%,5%and 10%BMT mouse serum and aGVHD mouse serum in the medium,respectively.The effect of serum in the two groups on the in vitro adipogenic differentiation ability of mouse MSCs was detected by Oil Red O staining.The expression levels of related proteins PPARy and CEBPα were detected by Western blot.The expression differences of key adipogenic transcription factors including PPARy,CEBPα,FABP4 and LPL were determined by real-time quantitative PCR(RT-qPCR).Results:An in vitro cell model simulating the damage of bone marrow microenvironment in mice with aGVHD was successfully established.Oil Red O staining showed that the number of orange-red fatty droplets was significantly reduced and the adipogenic differentiation ability of MSC was impaired at aGVHD serum concentration of 10%compared with BMT serum.Western blot experiments showed that adipogenesis-related proteins PPARy and CEBPα expressed in MSCs were down-regulated.Further RT-qPCR assay showed that the production of PPARy,CEBPα,FABP4 and LPL,the key transcription factors for adipogenic differentiation of MSC,were significantly reduced.Conclusion:The adipogenic differentiation capacity of MSCs is inhibited by aGVHD mouse serum.
9.Establishment and Evaluation Strategy of an in Vitro Cell Model of Bone Marrow Microenvironment Injury in Mouse Acute Graft-Versus-Host Disease
Jia-Yi TIAN ; Pei-Lin LI ; Jie TANG ; Run-Xiang XU ; Bo-Feng YIN ; Fei-Yan WANG ; Xiao-Tong LI ; Hong-Mei NING ; Heng ZHU ; Li DING
Journal of Experimental Hematology 2024;32(2):617-624
Objective:To establish a mesenchymal stem cell(MSC)-based in vitro cell model for the evaluation of mouse bone marrow acute graft-versus-host disease(aGVHD).Methods:Female C57BL/6N mice aged 6-8 weeks were used as bone marrow and lymphocyte donors,and female BALB/c mice aged 6-8 weeks were used as aGVHD recipients.The recipient mouse received a lethal dose(8.0 Gy,72.76 cGy/min)of total body γ irradiation,and injected with donor mouse derived bone marrow cells(1× 107/mouse)in 6-8 hours post irradiation to establish a bone marrow transplantation(BMT)mouse model(n=20).In addition,the recipient mice received a lethal dose(8.0 Gy,72.76 cGy/min)of total body γ irradiation,and injected with donor mouse derived bone marrow cells(1 × 107/mouse)and spleen lymphocytes(2 × 106/mouse)in 6-8 hours post irradiation to establish a mouse aGVHD model(n=20).On the day 7 after modeling,the recipient mice were anesthetized and the blood was harvested post eyeball enucleation.The serum was collected by centrifugation.Mouse MSCs were isolated and cultured with the addition of 2%,5%,and 10%recipient serum from BMT group or aGVHD group respectively.The colony-forming unit-fibroblast(CFU-F)experiment was performed to evaluate the potential effects of serums on the self-renewal ability of MSC.The expression of CD29 and CD105 of MSC was evaluated by immunofluorescence staining.In addition,the expression of self-renewal-related genes including Oct-4,Sox-2,and Nanog in MSC was detected by real-time fluorescence quantitative PCR(RT-qPCR).Results:We successfully established an in vitro cell model that could mimic the bone marrow microenvironment damage of the mouse with aGVHD.CFU-F assay showed that,on day 7 after the culture,compared with the BMT group,MSC colony formation ability of aGVHD serum concentrations groups of 2%and 5%was significantly reduced(P<0.05);after the culture,at day 14,compared with the BMT group,MSC colony formation ability in different aGVHD serum concentration was significantly reduced(P<0.05).The immunofluorescence staining showed that,compared with the BMT group,the proportion of MSC surface molecules CD29+and CD 105+cells was significantly dereased in the aGVHD serum concentration group(P<0.05),the most significant difference was at a serum concentration of 10%(P<0.001,P<0.01).The results of RT-qPCR detection showed that the expression of the MSC self-renewal-related genes Oct-4,Sox-2,and Nanog was decreased,the most significant difference was observed at an aGVHD serum concentration of 10%(P<0.01,P<0.001,P<0.001).Conclusion:By co-culturing different concentrations of mouse aGVHD serum and mouse MSC,we found that the addition of mouse aGVHD serum at different concentrations impaired the MSC self-renewal ability,which providing a new tool for the field of aGVHD bone marrow microenvironment damage.
10.Pathogen spectrum of hospitalized severe acute respiratory infection cases in a sentinel hospital in Tongzhou District of Beijing from 2019 to 2022
Lin ZOU ; Chong ZHANG ; Ling TONG ; Jianming ZHANG ; Jianguo WANG ; Fang WANG ; Xiang GAO ; Shujuan CUI ; Daitao ZHANG
Chinese Journal of Microbiology and Immunology 2024;44(7):596-600
Objective:To investigate the pathogen spectrum and the epidemiological characteristics of hospitalized severe acute respiratory tract infection (SARI) cases in a sentinel hospital in Tongzhou District of Beijing from 2019 to 2022, and provide reference for scientific prevention and control of SARI.Methods:This study enrolled SARI patients in the Beijing Luhe Hospital from January 2019 to December 2022. Nasopharyngeal swabs or respiratory secretions of the patients were collected and analyzed by quantitative real-time PCR to detect the pathogens and their types. The epidemiological and clinical characteristics of the cases were analyzed.Results:In this study, 1 124 SARI cases were enrolled, of which 379 were positive for respiratory pathogens with a detection rate of 33.72%. Most of the SARI cases were positive for bacteria pathogens, and the detection rates of Mycoplasma pneumoniae, Streptococcus pneumoniae, and Stenotrophomonas maltophilia were high. Influenza A virus, parainfluenza virus, and respiratory syncytial virus were the main viral pathogens detected in the cases. There were significant differences in the number of cases and the detection rate of respiratory pathogens among different age groups (χ 2=555, P=0.000 1). The predominant pathogens in different years were different. Mycoplasma pneumoniae [27.27% (51/187)] and influenza A virus [17.65% (33/187), ] were the predominant pathogens in 2019; parainfluenza virus [16.67% (10/60)], Mycoplasma pneumoniae [11.67% (7/60)], and Haemophilus influenzae [11.67% (7/60)] were the predominant pathogens in 2020; Stenotrophomonas maltophilia [24.39% (20/82)] and respiratory syncytial virus [19.51% (16/82)] were the predominant pathogens in 2021; Stenotrophomonas maltophilia [20% (10/50)] and parainfluenza virus [12% (6/50)] were the predominant pathogens in 2022. Conclusions:Most of the SARI cases in Tongzhou district of Beijing from 2019 to 2022 are caused by bacteria. More attention should be paid to the prevalence of Stenotrophomonas maltophilia and Mycoplasma pneumoniae, as well as the prevalence of respiratory syncytial virus, parainfluenza virus, and influenza A virus. The predominant pathogens change every year from 2019 to 2022. Therefore, the prevention and control strategies should be made accordingly. This study provides basis data for the national respiratory multipathogen surveillance program.

Result Analysis
Print
Save
E-mail