1.Evaluation of the application effectiveness and optimization strategies of confidential unit exclusion in Zhengzhou
Dan LIU ; Hongwei MA ; Tao WEN ; Yonglei LYU ; Mengru JI ; Ge SONG ; Huanyu LIU ; Mengdi FAN
Chinese Journal of Blood Transfusion 2026;39(3):379-383
Objective: To evaluate the practical effectiveness of confidential unit exclusion (CUE) in ensuring blood safety in Zhengzhou, analyze its application characteristics and existing problems, and provide a basis for optimizing blood safety management strategies. Methods: A retrospective analysis was conducted on CUE data handled by Henan Red Cross Blood Center from January 2019 to December 2024. Parameters such as the number of cases, demographic characteristics, reasons for exclusion, and time of report were statistically analyzed and compared with those of non-CUE. Results: From 2019 to 2024, the CUE reporting rate in Zhengzhou was 0.002 6% (40/1 547 666). CUE donors were predominantly male (65.00%, 26/40), aged 18-34 years (47.50%, 19/40), had college degree orabove (50.00%, 20/40), and were employees of enterprises or public institutions (32.50%, 13/40). Among the 40 CUE blood units, only one was reactive for anti-TP, while all others were qualified. The main reasons for CUE were recent vaccination (32.50%, 13/40), medical conditions unsuitable for donation (27.50%, 11/40), and high-risk sexual behavior (17.50%, 7/40). A total of 70.00% of reports occurred within 24 hours after donation, during which none of the corresponding blood units had been released; all units reported after more than 7 days had already been issued for clinical use, with no adverse transfusion reactions reported upon follow-up. Conclusion: The confidential unit exclusion program has played an active role in establishing a supplementary information feedback channel for blood donors. The procedure can be optimized by strengthening interactive communication and confirmation before donation, improving the accuracy of donors' self-assessment, and expanding convenient and rapid information-based reporting channels.
2.Clinical Characteristics and Prognostic Analysis of Extracranial Malignant Rhabdoid Tumor in Children
Shihan ZHANG ; Wen ZHAO ; Mei JIN ; Hongjun FAN ; Xisi WANG ; Libing FU ; Tong YU ; Yan SU
JOURNAL OF RARE DISEASES 2026;5(1):34-42
To investigate the clinical characteristics and prognosis of extracranial malignant rhabdoid tumor (eMRT) in children, and to provide a reference for the clinical treatment of this disease. A retrospective analysis was performed on the clinical data of children with newly diagnosed eMRT who were admitted and treated in the Department of Pediatric Oncology, Beijing Children's Hospital Affiliated to Capital Medical University, from March 2009 to December 2024. The clinical characteristics were summarized, and survival analysis and prognostic risk factor analysis were conducted. A total of 43 children with eMRT were included in this study, the median age at diagnosis of all patients was 20 months (range: 2-138 months). Among them, 24 cases were malignant renal rhabdoid tumors and 19 cases were extracranial, extrarenal rhabdoid tumors. Of the 43 children, 23 cases (53.5%) were complicated with distant metastasis. Twenty-nine (67.4%) underwent primary tumor resection. Among the children, 24 (55.8%) underwent gross total resection (GTR), 5 (11.6%) partial resection, and 14 (32.6%) biopsy only. Their 3-year overall survival (OS) rates were 40.8%, 35.3%, and 33.3%, respectively ( Children with eMRT have an overall poor prognosis. A diagnostic age < 12 months is an independent risk factor for higher mortality in these children. Further large-scale, long-term follow-up studies are needed to explore the prognostic factors of this disease.
3.Analysis of specific risks and long-term toxicities of BCR-ABL1 TKIs in pediatric patients with hematological malignancies
Luping WEN ; Fan XIA ; Ziqiong LIAO ; Benjie ZHOU ; Hui CHEN
China Pharmacy 2026;37(8):1050-1055
OBJECTIVE To analyze the specific risks and long-term toxicities of four BCR-ABL1 tyrosine kinase inhibitors (TKIs)(imatinib, dasatinib, nilotinib, and bosutinib) in pediatric patients with hematological malignancies. METHODS Adverse drug event (ADE) reports submitted to the the United States FDA Adverse Event Reporting System (FAERS) from January 2012 to December 2024, with imatinib, dasatinib, nilotinib, and bosutinib as the primary suspect drugs, were collected. Data mining was performed using the reporting odds ratio method and proportional reporting ratio method. ADE terms were classified and summarized by system organ class (SOC) and preferred term (PT) according to the Medical Dictionary for Drug Regulatory Activities (MedDRA, version 26.0). Meanwhile, the ADE reports were divided by age into the adult group (≥18 years) and the pediatric group (<18 years) to compare the differences in ADE between the two groups. RESULTS A total of 1 512 pediatric ADE reports were included: 993 for imatinib, 391 for dasatinib, 112 for nilotinib, and 16 for bosutinib. Among the reported ADEs, the patients were mainly aged 12-<18 years; the reports mainly originated from the United States, France, and Japan; and the primary indications were chronic myeloid leukemia and acute lymphoblastic leukemia. A total of 5 256 ADE signals were mined, among which 235 were positive signals, involving 1 103 PT across 27 SOC. The top five PT ranked by the number of positive signals were nausea, febrile neutropenia, abdominal pain, neutropenia, and anemia. The top two SOC were general disorders and administration site conditions, and gastrointestinal disorders. Compared with the adult group, the pediatric group had relatively higher proportions of events related to infections and infestations as well as blood and lymphatic system disorders. Pediatric long-term toxicity signals primarily included growth retardation, accompanied by signals related to endocrine system abnormalities and bone metabolism abnormalities. Specific signals included imatinib-associated septic shock, dasatinib-associated chylothorax, and nilotinib-associated electrocardiographic QT interval prolongation. CONCLUSIONS When pediatric patients use BCR-ABL1 TKIs, priority monitoring of infection risk and hematologic parameters is required, along with long-term follow-up of height, endocrine, and bone metabolism parameters. Targeted screening and management of drug-specific signals should be performed to ensure the long-term safety of pediatric medication.
4.Analysis of thermal environment and students thermal comfort in primary and secondary school classrooms in winter
Chinese Journal of School Health 2026;47(2):168-172
Objective:
To evaluate the current situation of thermal environment in primary and secondary school classrooms during winter, and to analyze students thermal comfort needs, so as to provide a basis for improving classroom thermal environment.
Methods:
From December 16 to 26, 2024, a stratified cluster random sampling method was used to select 90 classrooms from 15 primary and secondary schools in centralized/air conditioned heating areas(Liaoning Province, Tianjin City, Shanghai City) and naturally ventilated areas(Anhui Province and Jiangxi Province)for on site environmental measurement. A questionnaire survey was conducted among 743 students. The differences between groups using the χ 2 test were compared. Based on actual measurement data, a predicted mean vote prepared percentage of dissatisfied (PMV-PPD) model for centralized/air conditioned classrooms and an adaptive model for naturally ventilated classrooms were established, and the thermal neutral temperature and comfort interval were calculated.
Results:
The average outdoor temperature during on site measurement was 4.00(0.20,7.00)℃. In classrooms with centralized or air conditioned heating systems, the measured average temperature was (19.33±2.59)℃, with a thermal comfort range of 20.35-25.35 ℃ and a thermal neutral temperature of 22.85 ℃. And 13.92% of students reported feeling cold, while 80.80% felt comfortable. In classrooms with natural ventilation, the measured average temperature was (12.26±1.83)℃, with a thermal neutral temperature of 19.67 ℃ and a thermal comfort range of 16.17-23.17 ℃. About 48.33% of students reported feeling cold, and 49.81 % felt comfortable.The results of univariate analysis showed that there were statistically significant differences in shoe thickness, temperature sensation, relative humidity sensation and wind speed sensation between centralized/air conditioned heating areas ( χ 2= 7.01 , 31.47, 13.57, 13.80,all P <0.05). There were also statistically significant differences in school stage for primary and secondary school students, body mass index, classroom location for seat, temperature sensation, relative humidity sensation and wind speed sensation between naturally ventilated areas ( χ 2=42.13, 11.13, 11.04, 60.39, 29.27, 38.46,all P <0.05).
Conclusions
There are differences in thermal environment and students subjective thermal comfort in primary and secondary schools under different ventilation modes in winter. The temperature standards for heated classrooms should be revised, and differentiated environmental regulation strategies should be adopted based on different ventilation methods to improve students health and comfort levels.
5.Exercise improves microvascular function in patients with type 2 diabetes
Fan WEN ; Yang XIANG ; Huan ZHU ; Yanfang TUO ; Feng LI
Chinese Journal of Tissue Engineering Research 2026;30(5):1225-1235
BACKGROUND:Exercise is an effective way to improve microvascular function in patients with type 2 diabetes.In recent years,exercise has been used as an intervention therapy for microvascular dysfunction in patients with type 2 diabetes.However,few studies have systematically explored the influence of factors,such as"exercise type,exercise intensity and amount of exercise,"on microvascular function in patients.To some extent,this limits the formulation of precise exercise prescriptions to improve microvascular dysfunction in patients with type 2 diabetes and the comparison of study results.OBJECTIVE:To investigate the effects of exercise type,intensity,frequency and amount of exercise on microvascular function in patients with type 2 diabetes mellitus,and to make suggestions on exercise prescription.METHODS:The first author used computer to search the studies on the improvement of microvascular function in type 2 diabetes patients involving exercise in CNKI,WanFang,PubMed and other databases.The search terms were"diabetes mellitus,type 2 diabetes mellitus,microcirculation,microvascular reactivity,microvessels,capillaries,vasodilation,blood perfusion volume,endothelial cells,shear stress,exercise,aerobic exercise,resistance exercise,high-intensity exercise"in Chinese and English.The articles were screened by a quick glance at the article titles and abstracts to exclude those that were not closely related to the topic,and finally 60 articles were included for review.RESULTS AND CONCLUSION:(1)Exercise is an effective way to improve microvascular function in patients with type 2 diabetes.Aerobic exercise lasting 12-24 weeks,3-5 times/week,exercise time>30 minutes and intensity between 40%and 59%reserve oxygen intake can significantly improve microvascular function in patients with type 2 diabetes.On the basis of aerobic exercise,systemic resistance exercise 2-3 times a week(50%-85%1RM,every other day)or pressure resistance exercise can obtain better intervention effects.(2)In addition,exercise can improve microvascular function in patients with type 2 diabetes in a"dose-effect"manner,and patients can get better results from the intervention by increasing the amount of exercise,while maintaining safety.(3)The mechanism of exercise improving microvascular function in patients with type 2 diabetes is mainly related to promoting the release of nitric oxide and vascular endothelial growth factor from endothelial cells and inhibiting the release of endothelin1.
6.Exercise improves microvascular function in patients with type 2 diabetes
Fan WEN ; Yang XIANG ; Huan ZHU ; Yanfang TUO ; Feng LI
Chinese Journal of Tissue Engineering Research 2026;30(5):1225-1235
BACKGROUND:Exercise is an effective way to improve microvascular function in patients with type 2 diabetes.In recent years,exercise has been used as an intervention therapy for microvascular dysfunction in patients with type 2 diabetes.However,few studies have systematically explored the influence of factors,such as"exercise type,exercise intensity and amount of exercise,"on microvascular function in patients.To some extent,this limits the formulation of precise exercise prescriptions to improve microvascular dysfunction in patients with type 2 diabetes and the comparison of study results.OBJECTIVE:To investigate the effects of exercise type,intensity,frequency and amount of exercise on microvascular function in patients with type 2 diabetes mellitus,and to make suggestions on exercise prescription.METHODS:The first author used computer to search the studies on the improvement of microvascular function in type 2 diabetes patients involving exercise in CNKI,WanFang,PubMed and other databases.The search terms were"diabetes mellitus,type 2 diabetes mellitus,microcirculation,microvascular reactivity,microvessels,capillaries,vasodilation,blood perfusion volume,endothelial cells,shear stress,exercise,aerobic exercise,resistance exercise,high-intensity exercise"in Chinese and English.The articles were screened by a quick glance at the article titles and abstracts to exclude those that were not closely related to the topic,and finally 60 articles were included for review.RESULTS AND CONCLUSION:(1)Exercise is an effective way to improve microvascular function in patients with type 2 diabetes.Aerobic exercise lasting 12-24 weeks,3-5 times/week,exercise time>30 minutes and intensity between 40%and 59%reserve oxygen intake can significantly improve microvascular function in patients with type 2 diabetes.On the basis of aerobic exercise,systemic resistance exercise 2-3 times a week(50%-85%1RM,every other day)or pressure resistance exercise can obtain better intervention effects.(2)In addition,exercise can improve microvascular function in patients with type 2 diabetes in a"dose-effect"manner,and patients can get better results from the intervention by increasing the amount of exercise,while maintaining safety.(3)The mechanism of exercise improving microvascular function in patients with type 2 diabetes is mainly related to promoting the release of nitric oxide and vascular endothelial growth factor from endothelial cells and inhibiting the release of endothelin1.
7.The Role and Molecular Mechanism of N⁶-methyladenosine Modification in Spermatogenesis
Shi-Qi MENG ; Wen-Ting LU ; Xu CHENG ; Fan YANG ; Chang-Min NIU ; Ying ZHEGN
Progress in Biochemistry and Biophysics 2026;53(5):1297-1312
Spermatogenesis is a highly ordered and spatiotemporally regulated developmental process in the male reproductive system, during which spermatogonial stem cells (SSCs), supported by the seminiferous tubule microenvironment, sequentially undergo mitosis, meiosis, and spermiogenesis to ultimately generate structurally intact spermatozoa. This complex process is accompanied by extensive transcriptional reprogramming, chromatin remodeling, and finely tuned post-transcriptional regulation. Precise control of RNA fate is therefore essential for maintaining the continuity and fidelity of spermatogenesis, and its disruption represents a major molecular basis of male infertility. N6-methyladenosine (m6A), the most abundant internal RNA modification in eukaryotes, has emerged as a critical regulator of post-transcriptional gene expression. m6A methyltransferases (“writers”) catalyze the addition of a methyl group to the N6 position of adenosine, m6A demethylases (“erasers”) remove the modification, and m6A-binding proteins (“readers”) recognize m6A-modified transcripts. Through the coordinated actions of these factors, m6A regulates transcript fate at multiple levels, including RNA splicing, nuclear export, stability, translation, and decay. Emerging evidence indicates that m6A-mediated regulation is essential across multiple stages of spermatogenesis, including SSC self-renewal and differentiation, meiotic progression, maintenance of chromosomal stability, and sperm morphogenesis. Beyond its intrinsic functions in germ cells, m6A also contributes to the regulation of the testicular microenvironment. In sertoli cells, m6A is involved in maintaining blood-testis barrier integrity, RNA processing, and paracrine signaling, thereby providing structural and metabolic support for germ cell development. In Leydig cells, m6A regulates steroidogenesis, particularly testosterone synthesis, and participates in cellular stress responses and metabolic homeostasis. Through these mechanisms, m6A indirectly influences spermatogenesis by modulating the functional state of testicular somatic cells, highlighting an integrated regulatory mode that combines cell-intrinsic and microenvironment-mediated effects. Notably, distinct classes of m6A regulators exhibit pronounced stage-specific functions and coordinated division of labor, collectively forming a multilayered and dynamic regulatory network. Writers often display dosage- and temporal window-dependent effects; erasers contribute to stage-specific demethylation and functional compensation; while readers function through a “switch-buffer” dual-layer architecture, and RNA-binding proteins (RBPs) participate in substrate selection and post-transcriptional regulation. Importantly, emerging evidence suggests that some m6A-related proteins can function through noncanonical mechanisms independent of m6A recognition, such as intrinsic RNA-binding activity, helicase function, or ribonucleoprotein complex assembly, thereby expanding the functional landscape of the m6A regulatory system. Dysregulation of m6A machinery can lead to multiple spermatogenic defects, including impaired SSC self-renewal, meiotic arrest, abnormal chromatin remodeling, and defective sperm formation, ultimately resulting in male infertility. Despite substantial advances, several critical questions remain unresolved, including the distinction between m6A-dependent and -independent mechanisms, the spatiotemporal dynamics of m6A modifications at single-cell resolution, and the coordination and antagonism among different regulatory factors. In this review, we systematically summarize the dual regulation of spermatogenesis by germ cell-intrinsic mechanisms and the testicular microenvironment, and delineate the molecular mechanisms and stage-specific functions of the dynamic m6A regulatory network. We further discuss the current limitations in the field and propose feasible experimental strategies for future investigation. Collectively, this work aims to provide a comprehensive framework for understanding the epitranscriptomic regulation of spermatogenesis and to offer theoretical insights into the pathogenesis and clinical management of male infertility.
8.The Role and Molecular Mechanism of N⁶-methyladenosine Modification in Spermatogenesis
Shi-Qi MENG ; Wen-Ting LU ; Xu CHENG ; Fan YANG ; Chang-Min NIU ; Ying ZHEGN
Progress in Biochemistry and Biophysics 2026;53(5):1297-1312
Spermatogenesis is a highly ordered and spatiotemporally regulated developmental process in the male reproductive system, during which spermatogonial stem cells (SSCs), supported by the seminiferous tubule microenvironment, sequentially undergo mitosis, meiosis, and spermiogenesis to ultimately generate structurally intact spermatozoa. This complex process is accompanied by extensive transcriptional reprogramming, chromatin remodeling, and finely tuned post-transcriptional regulation. Precise control of RNA fate is therefore essential for maintaining the continuity and fidelity of spermatogenesis, and its disruption represents a major molecular basis of male infertility. N6-methyladenosine (m6A), the most abundant internal RNA modification in eukaryotes, has emerged as a critical regulator of post-transcriptional gene expression. m6A methyltransferases (“writers”) catalyze the addition of a methyl group to the N6 position of adenosine, m6A demethylases (“erasers”) remove the modification, and m6A-binding proteins (“readers”) recognize m6A-modified transcripts. Through the coordinated actions of these factors, m6A regulates transcript fate at multiple levels, including RNA splicing, nuclear export, stability, translation, and decay. Emerging evidence indicates that m6A-mediated regulation is essential across multiple stages of spermatogenesis, including SSC self-renewal and differentiation, meiotic progression, maintenance of chromosomal stability, and sperm morphogenesis. Beyond its intrinsic functions in germ cells, m6A also contributes to the regulation of the testicular microenvironment. In sertoli cells, m6A is involved in maintaining blood-testis barrier integrity, RNA processing, and paracrine signaling, thereby providing structural and metabolic support for germ cell development. In Leydig cells, m6A regulates steroidogenesis, particularly testosterone synthesis, and participates in cellular stress responses and metabolic homeostasis. Through these mechanisms, m6A indirectly influences spermatogenesis by modulating the functional state of testicular somatic cells, highlighting an integrated regulatory mode that combines cell-intrinsic and microenvironment-mediated effects. Notably, distinct classes of m6A regulators exhibit pronounced stage-specific functions and coordinated division of labor, collectively forming a multilayered and dynamic regulatory network. Writers often display dosage- and temporal window-dependent effects; erasers contribute to stage-specific demethylation and functional compensation; while readers function through a “switch-buffer” dual-layer architecture, and RNA-binding proteins (RBPs) participate in substrate selection and post-transcriptional regulation. Importantly, emerging evidence suggests that some m6A-related proteins can function through noncanonical mechanisms independent of m6A recognition, such as intrinsic RNA-binding activity, helicase function, or ribonucleoprotein complex assembly, thereby expanding the functional landscape of the m6A regulatory system. Dysregulation of m6A machinery can lead to multiple spermatogenic defects, including impaired SSC self-renewal, meiotic arrest, abnormal chromatin remodeling, and defective sperm formation, ultimately resulting in male infertility. Despite substantial advances, several critical questions remain unresolved, including the distinction between m6A-dependent and -independent mechanisms, the spatiotemporal dynamics of m6A modifications at single-cell resolution, and the coordination and antagonism among different regulatory factors. In this review, we systematically summarize the dual regulation of spermatogenesis by germ cell-intrinsic mechanisms and the testicular microenvironment, and delineate the molecular mechanisms and stage-specific functions of the dynamic m6A regulatory network. We further discuss the current limitations in the field and propose feasible experimental strategies for future investigation. Collectively, this work aims to provide a comprehensive framework for understanding the epitranscriptomic regulation of spermatogenesis and to offer theoretical insights into the pathogenesis and clinical management of male infertility.
9.Feixin Decoction Treats Hypoxic Pulmonary Hypertension by Regulating Pyroptosis in PASMCs via PPARγ/NF-κB/NLRP3 Signaling Pathway
Junlan TAN ; Xianya CAO ; Runxiu ZHENG ; Wen ZHANG ; Chao ZHANG ; Jian YI ; Feiying WANG ; Xia LI ; Jianmin FAN ; Hui LIU ; Lan SONG ; Aiguo DAI
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(18):1-9
ObjectiveTo investigate the mechanism by which Feixin decoction treats hypoxic pulmonary hypertension (HPH) by regulating the peroxisome proliferator-activated receptor gamma (PPARγ)/nuclear factor-kappa B (NF-κB)/NOD-like receptor pyrin domain containing 3 (NLRP3) signaling pathway. MethodsForty-eight male SD rats were randomly allocated into normal, hypoxia, and low-, medium- and high-dose (5.85, 11.7, 23.4 g·kg-1, respectively) Feixin decoction groups, with 8 rats in each group. Except the normal group, the remaining five groups were placed in a hypoxia chamber with an oxygen concentration of (10.0±0.5)% for 8 h per day, 28 days, and administrated with corresponding drugs during the modeling process. After 4 weeks of treatment, echocardiographic parameters [pulmonary artery acceleration time (PAT), pulmonary artery ejection time (PET), right ventricular anterior wall thickness (RVAWd), and tricuspid annular plane systolic excursion (TAPSE)] were measured for each group. The right ventricular systolic pressure (RVSP) was measured by the right heart catheterization method, and the right ventricular hypertrophy index (RVHI) was calculated by weighing the heart. The pathological changes in pulmonary arterioles were observed by hematoxylin-eosin staining. The co-localization of α-smooth muscle actin (α-SMA) with NLRP3, N-terminal gasdermin D (N-GSDMD), and cysteinyl aspartate-specific proteinase-1 (Caspase-1) in pulmonary arteries was detected by immunofluorescence. The protein levels of PPARγ, NF-κB, NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), N-GSDMD, interleukin-1β (IL-1β), interleukin-18(IL-18), and cleaved Caspase-1 in the lung tissue was determined by Western blot. The ultrastructural changes in pulmonary artery smooth muscle cells (PASMCs) were observed by transmission electron microscopy. ResultsCompared with the normal group, the hypoxia group showed increased RVSP and RVHI (P<0.01), decreased right heart function (P<0.01), increased pulmonary vascular remodeling (P<0.01), increased co-localization of α-SMA with NLRP3, N-GSDMD, and Caspase-1 in pulmonary arterioles (P<0.01), up-regulated protein levels of NF-κB, NLRP3, ASC, N-GSDMD, IL-1β, IL-18, and cleaved Caspase-1 in the lung tissue (P<0.05, P<0.01), a down-regulated protein level of PPARγ (P<0.05, P<0.01), and pyroptosis in PASMCs. Compared with the hypoxia group, Feixin decoction reduced RVSP and RVHI, improved the right heart function and ameliorated pulmonary vascular remodeling (P<0.05, P<0.01), decreased the co-localization of α-SMA with NLRP3, N-GSDMD, and Caspase-1 (P<0.05, P<0.01), down-regulated the protein levels of NF-κB, NLRP3, ASC, N-GSDMD, IL-1β, IL-18, and cleaved Caspase-1 in the lung tissue (P<0.05, P<0.01), up-regulated the protein level of PPARγ (P<0.05, P<0.01), and alleviated pyroptosis in PASMCs. ConclusionFeixin decoction can ameliorate pulmonary vascular remodeling and right heart dysfunction in chronically induced HPH rats by regulating pyroptosis in PASMCs through the PPARγ/NF-κB/NLRP3 pathway.
10.Dynamic Monitoring and Analysis of Ammonia Concentration in Laboratory Animal Facilities Under Suspension of Heating Ventilation and Air Conditioning System
Qingzhen JIAO ; Guihua WU ; Wen TANG ; Fan FAN ; Kai FENG ; Chunxiang YANG ; Jian QIAO ; Sufang DENG
Laboratory Animal and Comparative Medicine 2025;45(4):490-495
ObjectiveTo monitor the real-time changes in ammonia concentration in the laboratory animal facility environment before, during, and after the air conditioning system stops supplying air, so as to provide a basis and reference for developing emergency plans for the shutdown of the air conditioning system. MethodsThe laboratory animal facilities of the Wuhan Institute of Biological Products were used as the research object. Ammonia concentration detectors were used to monitor ammonia concentration continuously in the environment of conventional rabbit production facility, SPF hamster production facility, and SPF guinea pig experimental facility before and after the passive shutdown due to repairs and active maintenance shutdown of the air conditioning system, as well as the time for the ammonia concentration to return to daily levels after resuming air supply. ResultsUnder both shutdown modes of the air conditioning system, the trend of ammonia concentration changes in different laboratory animal facilities was consistent, showing a rapid increase after shutdown and a rapid decrease after resuming air supply. Under active maintenance shutdown, the maximum ammonia concentrations in the conventional rabbit production facilities, SPF hamster production facilities, and SPF guinea pig experimental facilities were 9.81 mg/m³, 14.27 mg/m³, and 6.98 mg/m³, respectively. Within 12 minutes after resuming air supply, ammonia concentration could return to normal daily levels. Under passive long-term shutdown, ammonia concentration value was positively correlated with the duration of air supply suspension. As the shutdown duration increased, ammonia concentration continued to increase. The maximum ammonia concentration values in the three facilities occurred at 88 minutes (38.06 mg/m³), 40 minutes (18.43 mg/m³), and 34 minutes (15.61 mg/m³) after air supply suspension, respectively.Within 11 minutes after resuming air supply, ammonia concentration could return to normal daily levels. ConclusionShutdown of the air conditioning system causes a rapid increase in ammonia concentration in laboratory animal facilities, and the rise in ammonia concentration is positively correlated with the duration of air supply suspension. Therefore, when an emergency shutdown of the air-conditioning system is required due to maintenance or other reasons, backup fans should be provided in accordance with the requirements of GB 50447-2008 "Architectural and Technical Code for Laboratory Animal Facilities". Older facilities should make adequate preparations and develop a scientifically sound emergency plan.


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