1.Current Status, Trends, and Opportunities in the Study of Computable Phenotypes for Rare Diseases
Jindong WU ; Qiaorui WEN ; Jian GUO ; Shengfeng WANG
JOURNAL OF RARE DISEASES 2026;5(1):90-99
Disease computable phenotype is a data model designed to identify specific clinical conditions or characteristics, which automatically extracts information from clinical databases such as electronic health records through algorithms. Phenotypic data for rare diseases often reside in unstructured text. Due to the scarcity of rare disease cases, atypical symptoms, and insufficient physician experience, misdiagnosis and underdiagnosis rates remain high. In this context, the application of computable phenotype technology holds promise for improving the accuracy and efficiency of rare disease diagnosis. This article reviews the current research status, challenges, and opportunities of computable phenotype technology in biomedicine, particularly in the field of rare diseases, and proposes a development and validation framework for rare disease computable phenotypes, aiming to provide research and development insights for computable phenotypes to empower the diagnosis and treatment of rare diseases.
2.Clinical features and multimodal quantitative radiological features of primary liver cancer patients with different traditional Chinese medicine syndrome types
Feng WU ; Muqing LUO ; Wantingting WEN ; Ziwei CAI ; Yinqi LIU ; Jian XIANG ; Xiaona ZHOU ; Qian GUO ; Kun ZHANG
Journal of Clinical Hepatology 2026;42(5):1093-1100
ObjectiveTo investigate the association of the traditional Chinese medicine (TCM) syndrome types of primary liver cancer (PLC) with clinical features and multimodal quantitative radiological features on computed tomography (CT) and magnetic resonance imaging (MRI), and to provide a reference for the objectification of TCM syndrome differentiation and precise diagnosis and treatment. MethodsA retrospective analysis was performed for the clinical data of 312 patients who were diagnosed with PLC in The First Affiliated Hospital of Hunan University of Chinese Medicine from March 2020 to June 2025, and according to the TCM syndrome type, they were divided into stagnation of liver Qi group with 40 patients, stagnation of liver Qi and spleen deficiency group with 109 patients, Qi stagnation and blood stasis group with 62 patients, dampness-heat toxin amassment group with 81 patients, and liver-kidney Yin deficiency group with 20 patients. Clinical features and multimodal quantitative radiological features were compared between the patients with different TCM syndrome types. A one-way analysis of variance was used for comparison of normally distributed continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups; the Kruskal-Wallis H test was used for comparison of non-normally distributed continuous data between multiple groups, and the Dunn’s multiple test was used for further comparison between two groups; the chi-square test was used for comparison of categorical data between groups, and the Bonferroni method was used for further comparison between two groups. ResultsThere were significant differences between the patients with different TCM syndrome types in China liver cancer staging (CNLC), Child-Pugh class, alanine aminotransferase, aspartate aminotransferase, albumin, direct bilirubin, total bilirubin, prothrombin time, neutrophil, and albumin-bilirubin score (all P<0.05). In the stagnation of liver Qi group, the patients with Child-Pugh class A accounted for 75.00%; among the patients with CNLC stage I PLC, the patients with stagnation of liver Qi accounted for 60.00%, and those with Qi stagnation and blood stasis syndrome accounted for 59.68%, while among the patients with CNLC stage IV PLC, the distribution proportion of dampness-heat toxin amassment (27.16%) and liver-kidney Yin deficiency (30.00%) was significantly higher than that of stagnation of liver Qi (2.50%) (all P<0.05). Radiological examination showed that there were significant differences between the patients with different TCM syndrome types in the number of tumors, ascites, venous tumor thrombus, maximum tumor diameter, intrahepatic metastasis, and lymph node metastasis in the hepatic hilar and retroperitoneal regions (all P<0.05). Compared with the patients with stagnation of liver Qi, the patients with liver depression and spleen deficiency or liver-kidney Yin deficiency were more likely to develop intrahepatic metastasis; the patients with liver depression and spleen deficiency, dampness-heat toxin amassment, or liver-kidney Yin deficiency were more likely to develop lymph node metastasis in the hepatic hilar and retroperitoneal regions; the patients with liver-kidney Yin deficiency were more likely to experience multiple tumors; the patients with liver depression and spleen deficiency or dampness-heat toxin amassment were more likely to develop ascites (all P<0.05). Compared with the patients with Qi stagnation and blood stasis syndrome, the patients with liver depression and spleen deficiency had a significantly longer maximum tumor diameter and a significantly higher proportion of patients with venous tumor thrombus (both P<0.05). Furthermore, among the 184 patients with MRI diffusion-weighted imaging sequences, the patients with dampness-heat toxin amassment or Qi stagnation and blood stasis syndrome had significantly higher ADC values and relative ADC values than those with stagnation of liver Qi (all P<0.05). ConclusionThere are significant differences in CT/MRI radiological features and clinical features between PLC patients with different TCM syndrome types, among whom the patients with liver depression and spleen deficiency, dampness-heat toxin amassment, and liver-kidney Yin deficiency tend to exhibit progressive radiological features, and those with dampness-heat toxin amassment or Qi stagnation and blood stasis syndrome tend to have higher ADC values. These findings provide an objective basis for TCM syndrome differentiation in PLC.
3.Latent tuberculosis infection among the elderly in Nanchuan District
ZHANG Wen ; WU Chengguo ; ZHENG Denghu ; LUO Jiankui ; LUO Jie ; SUN Jian ; ZHANG Liyi ; LEI Rongrong ; LIAO Wenping
Journal of Preventive Medicine 2026;38(4):338-342
Objective:
To analyze the current status and influencing factors for latent tuberculosis infection (LTBI) among the elderly in Nanchuan District, Chongqing Municipality, so as to provide a reference for developing targeted prevention and control measures and reducing the risk of tuberculosis incidence.
Methods:
From June to December 2024, a multi-stage random cluster sampling method combined with probability proportional to population size sampling was used to select residents aged ≥65 years from four townships (streets) in Nanchuan District as study participants. Demographic information, disease history, and history of close contact with tuberculosis were collected through a questionnaire survey. Tuberculin skin test (TST) was used to detect Mycobacterium tuberculosis infection. LTBI was defined as a mean induration diameter of ≥10 mm on the TST, with active pulmonary tuberculosis excluded. Factors affecting LTBI among the elderly were identified using a multivariable logistic regression model.
Results:
A total of 3 699 participants were surveyed, including 1 707 males (46.15%) and 1 992 females (53.85%). The median age was 71.00 (interquartile range, 8.00) years. There were 285 participants (7.70%) with pulmonary disease, 18 (0.49%) with immune system disease, 47 (1.27%) with a history of tuberculosis, and 17 (0.46%) with a history of close contact with tuberculosis. LTBI was detected in 628 participants, with a detection rate of 16.98%. Multivariable logistic regression analysis showed that elderly participants with senior high school education or above (OR=2.292, 95%CI: 1.508-3.484), those with immune system disease (OR=3.226, 95%CI: 1.240-8.393), and those with a history of tuberculosis (OR=4.797, 95%CI: 2.436-9.447) were significantly associated with a higher risk of LTBI.
Conclusions
The detection rate of LTBI among the elderly in Nanchuan District was relatively low. Educational level, immune system disease, and history of tuberculosis were influencing factors for LTBI risk in this population. It is necessary to strengthen health education, screening, and preventive interventions.
4.Complications among patients undergoing orthopedic surgery after infection with the SARS-CoV-2 Omicron strain and a preliminary nomogram for predicting patient outcomes.
Liang ZHANG ; Wen-Long GOU ; Ke-Yu LUO ; Jun ZHU ; Yi-Bo GAN ; Xiang YIN ; Jun-Gang PU ; Huai-Jian JIN ; Xian-Qing ZHANG ; Wan-Fei WU ; Zi-Ming WANG ; Yao-Yao LIU ; Yang LI ; Peng LIU
Chinese Journal of Traumatology 2025;28(6):445-453
PURPOSE:
The rate of complications among patients undergoing surgery has increased due to infection with SARS-CoV-2 and other variants of concern. However, Omicron has shown decreased pathogenicity, raising questions about the risk of postoperative complications among patients who are infected with this variant. This study aimed to investigate complications and related factors among patients with recent Omicron infection prior to undergoing orthopedic surgery.
METHODS:
A historical control study was conducted. Data were collected from all patients who underwent surgery during 2 distinct periods: (1) between Dec 12, 2022 and Jan 31, 2023 (COVID-19 positive group), (2) between Dec 12, 2021 and Jan 31, 2022 (COVID-19 negative control group). The patients were at least 18 years old. Patients who received conservative treatment after admission or had high-risk diseases or special circumstances (use of anticoagulants before surgery) were excluded from the study. The study outcomes were the total complication rate and related factors. Binary logistic regression analysis was used to identify related factors, and odds ratio (OR) and 95% confidence interval (CI) were calculated to assess the impact of COVID-19 infection on complications.
RESULTS:
In the analysis, a total of 847 patients who underwent surgery were included, with 275 of these patients testing positive for COVID-19 and 572 testing negative. The COVID-19-positive group had a significantly higher rate of total complications (11.27%) than the control group (4.90%, p < 0.001). After adjusting for relevant factors, the OR was 3.08 (95% CI: 1.45-6.53). Patients who were diagnosed with COVID-19 at 3-4 weeks (OR = 0.20 (95% CI: 0.06-0.59), p = 0.005), 5-6 weeks (OR = 0.16 (95% CI: 0.04-0.59), p = 0.010), or ≥7 weeks (OR = 0.26 (95% CI: 0.06-1.02), p = 0.069) prior to surgery had a lower risk of complications than those who were diagnosed at 0-2 weeks prior to surgery. Seven factors (age, indications for surgery, time of operation, time of COVID-19 diagnosis prior to surgery, C-reactive protein levels, alanine transaminase levels, and aspartate aminotransferase levels) were found to be associated with complications; thus, these factors were used to create a nomogram.
CONCLUSION
Omicron continues to be a significant factor in the incidence of postoperative complications among patients undergoing orthopedic surgery. By identifying the factors associated with these complications, we can determine the optimal surgical timing, provide more accurate prognostic information, and offer appropriate consultation for orthopedic surgery patients who have been infected with Omicron.
Humans
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COVID-19/complications*
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Male
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Female
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Middle Aged
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Postoperative Complications/epidemiology*
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SARS-CoV-2
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Orthopedic Procedures/adverse effects*
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Aged
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Nomograms
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Adult
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Retrospective Studies
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Risk Factors
5.Micronucleus counts correlating with male infertility: a clinical analysis of chromosomal abnormalities and reproductive parameters.
Shun-Han ZHANG ; Ying-Jun XIE ; Wen-Jun QIU ; Qian-Ying PAN ; Li-Hao CHEN ; Jian-Feng WU ; Si-Qi HUANG ; Ding WANG ; Xiao-Fang SUN
Asian Journal of Andrology 2025;27(4):537-542
Investigating the correlation between micronucleus formation and male infertility has the potential to improve clinical diagnosis and deepen our understanding of pathological progression. Our study enrolled 2252 male patients whose semen was analyzed from March 2023 to July 2023. Their clinical data, including semen parameters and age, were also collected. Genetic analysis was used to determine whether the sex chromosome involved in male infertility was abnormal (including the increase, deletion, and translocation of the X and Y chromosomes), and subsequent semen analysis was conducted for clinical grouping purposes. The participants were categorized into five groups: normozoospermia, asthenozoospermia, oligozoospermia, oligoasthenozoospermia, and azoospermia. Patients were randomly selected for further study; 41 patients with normozoospermia were included in the control group and 117 patients with non-normozoospermia were included in the study group according to the proportions of all enrolled patients. Cytokinesis-block micronucleus (CBMN) screening was conducted through peripheral blood. Statistical analysis was used to determine the differences in micronuclei (MNi) among the groups and the relationships between MNi and clinical data. There was a significant increase in MNi in infertile men, including those with azoospermia, compared with normozoospermic patients, but there was no significant difference between the genetic and nongenetic groups in azoospermic men. The presence of MNi was associated with sperm concentration, progressive sperm motility, immotile spermatozoa, malformed spermatozoa, total sperm count, and total sperm motility. This study underscores the potential utility of MNi as a diagnostic tool and highlights the need for further research to elucidate the underlying mechanisms of male infertility.
Humans
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Male
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Infertility, Male/genetics*
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Adult
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Micronucleus Tests
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Semen Analysis
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Oligospermia/genetics*
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Azoospermia/genetics*
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Chromosome Aberrations
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Sperm Count
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Micronuclei, Chromosome-Defective
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Middle Aged
6.Diagnosis and treatment guideline for acute cervical spinal cord injury without fracture-dislocation in adults (version 2025)
Qingde WANG ; Tongwei CHU ; Jian DONG ; Liangjie DU ; Haoyu FENG ; Shunwu FAN ; Shiqing FENG ; Yanzheng GAO ; Yong HAI ; Da HE ; Dianming JIANG ; Jianyuan JIANG ; Bin LIN ; Bin LIU ; Baoge LIU ; Fang LI ; Feng LI ; Li LI ; Weishi LI ; Fangcai LI ; Xiaoguang LIU ; Hongjian LIU ; Yong LIU ; Zhongjun LIU ; Shibao LU ; Xuhua LU ; Keya MAO ; Xuexiao MA ; Yong QIU ; Limin RONG ; Jun SHU ; Yueming SONG ; Tiansheng SUN ; Yan WANG ; Zhe WANG ; Zheng WANG ; Bing WANG ; Linfeng WANG ; Yu WANG ; Qinghe WANG ; Jigong WU ; Hong XIA ; Guoyong YIN ; Jinglong YAN ; Wen YUAN ; Yong YANG ; Qiang YANG ; Cao YANG ; Jie ZHAO ; Jianguo ZHANG ; Yue ZHU ; Zezhang ZHU ; Yingjie ZHOU ; Zhongmin ZHANG ; Yan ZENG ; Dingjun HAO ; Baorong HE ; Wei MEI
Chinese Journal of Trauma 2025;41(3):243-252
Cervical spinal cord injury without fracture-dislocation (CSCIWFD) is referred to as a special type of cervical spinal cord injury characterized by traumatic spinal cord dysfunction and no significant bony structural abnormalities on imagines. Duo to the high risk of missed diagnosis during the initial consultation, CSCIWFD may lead to progressive neurological deterioration or even complete paralysis, severely impacting patients′ prognosis. Currently, there are no established consensuses over the diagnosis and treatment of CSCIWFD, such as the lack of evidence-based standards for indications of non-surgical treatment and risk of secondary neurological injury, as well as debates over the optimal timing for surgical intervention and indications for different surgical approaches. To address these issues, the Spine Trauma Group of the Orthopedic Branch of the Chinese Medical Doctor Association organized experts in the relevant fields to formulate Diagnosis and treatment guideline for acute cervical spinal cord injury without fracture- dislocation in adults ( version 2025) . Based on evidence-based medicine and the principles of scientific rigor and clinical applicability, the guidelines proposed 11 recommendations covering terminology, diagnosis, evaluation treatment, and rehabilitation, etc., aiming to standardize the management of CSCIWFD.
7.Guideline for Adult Weight Management in China
Weiqing WANG ; Qin WAN ; Jianhua MA ; Guang WANG ; Yufan WANG ; Guixia WANG ; Yongquan SHI ; Tingjun YE ; Xiaoguang SHI ; Jian KUANG ; Bo FENG ; Xiuyan FENG ; Guang NING ; Yiming MU ; Hongyu KUANG ; Xiaoping XING ; Chunli PIAO ; Xingbo CHENG ; Zhifeng CHENG ; Yufang BI ; Yan BI ; Wenshan LYU ; Dalong ZHU ; Cuiyan ZHU ; Wei ZHU ; Fei HUA ; Fei XIANG ; Shuang YAN ; Zilin SUN ; Yadong SUN ; Liqin SUN ; Luying SUN ; Li YAN ; Yanbing LI ; Hong LI ; Shu LI ; Ling LI ; Yiming LI ; Chenzhong LI ; Hua YANG ; Jinkui YANG ; Ling YANG ; Ying YANG ; Tao YANG ; Xiao YANG ; Xinhua XIAO ; Dan WU ; Jinsong KUANG ; Lanjie HE ; Wei GU ; Jie SHEN ; Yongfeng SONG ; Qiao ZHANG ; Hong ZHANG ; Yuwei ZHANG ; Junqing ZHANG ; Xianfeng ZHANG ; Miao ZHANG ; Yifei ZHANG ; Yingli LU ; Hong CHEN ; Li CHEN ; Bing CHEN ; Shihong CHEN ; Guiyan CHEN ; Haibing CHEN ; Lei CHEN ; Yanyan CHEN ; Genben CHEN ; Yikun ZHOU ; Xianghai ZHOU ; Qiang ZHOU ; Jiaqiang ZHOU ; Hongting ZHENG ; Zhongyan SHAN ; Jiajun ZHAO ; Dong ZHAO ; Ji HU ; Jiang HU ; Xinguo HOU ; Bimin SHI ; Tianpei HONG ; Mingxia YUAN ; Weibo XIA ; Xuejiang GU ; Yong XU ; Shuguang PANG ; Tianshu GAO ; Zuhua GAO ; Xiaohui GUO ; Hongyi CAO ; Mingfeng CAO ; Xiaopei CAO ; Jing MA ; Bin LU ; Zhen LIANG ; Jun LIANG ; Min LONG ; Yongde PENG ; Jin LU ; Hongyun LU ; Yan LU ; Chunping ZENG ; Binhong WEN ; Xueyong LOU ; Qingbo GUAN ; Lin LIAO ; Xin LIAO ; Ping XIONG ; Yaoming XUE
Chinese Journal of Endocrinology and Metabolism 2025;41(11):891-907
Body weight abnormalities, including overweight, obesity, and underweight, have become a dual public health challenge in Chinese adults: overweight and obesity lead to a variety of chronic complications, while underweight increases the risks of malnutrition, sarcopenia, and organ dysfunction. To systematically address these issues, multidisciplinary experts in endocrinology, sports science, nutrition, and psychiatry from various regions have held multiple weight management seminars. Based on the latest epidemiological data and clinical evidence, they expanded the guideline to include assessment and intervention strategies for underweight, in addition to the core content of obesity management. This guideline outlines the etiological mechanisms, evaluation methods, and multidimensional management strategies for overweight and obesity, covering key areas such as diagnosis and assessment, medical nutrition therapy, exercise prescription, pharmacological intervention, and psychological support. It is intended to provide a scientific and standardized approach to weight management across the adult population, aiming to curb the rising prevalence of obesity, mitigate complications associated with abnormal body weight, and improve nutritional status and overall quality of life.
8.Establishment and evaluation of a lipopolysaccharide-induced acute respiratory distress syndrome model in minipigs
Chuang-Ye WANG ; Ran WANG ; Jian ZHANG ; Ling-Xiao QIU ; Bin QING ; Heng YOU ; Jin-Cheng LIU ; Bin WANG ; Nan-Bo WANG ; Jia-Yu LI ; Xing LIU ; Shuang WANG ; Jin HU ; Jian WEN ; Quan LI ; Xiao-Ou HUANG ; Kun ZHAO ; Shuang-Lin LIU ; Gang LIU ; Mei-Ju WANG ; Qing XIANG ; Hong-Mei WU ; Xiao-Rong SUN ; Tao GU ; Dong ZHANG ; Qi LI ; Zhi XU
Medical Journal of Chinese People's Liberation Army 2025;50(9):1154-1161
Objective To establish a stable,reliable,and clinically relevant porcine model of endotoxin-induced acute respiratory distress syndrome(ARDS).Methods Ten 8-month-old male Bama minipigs were deeply sedated,followed by invasive mechanical ventilation and electrocardiographic monitoring.Lipopolysaccharide(LPS)was intravenously pumped at 600 μg/(kg·h)for 3 hours,then maintained at 15 μg/(kg·h)thereafter.Dynamic monitoring was performed at five time points after LPS injection(LPS 0,1,3,5,and 8 h),including arterial blood gas analysis and chest computed tomography(CT)scans.Pathological examination of lung tissues obtained via bronchoscopic biopsy(HE staining and transmission electron microscopy)was conducted.These indicators were comprehensively used to evaluate the success of the animal model.Results At 5 hours after LPS administration,8 minipigs developed symptoms such as skin cyanosis,elevated body temperature,and respiratory distress.The oxygenation index decreased to<300 mmHg.Chest CT scans showed diffuse pulmonary infiltrates.Histopathology revealed alveolar edema and hyaline membrane formation.Transmission electron microscopy demonstrated disruption of pulmonary blood-air barrier,depletion of lamellar bodies in type Ⅱ pneumocytes,inflammatory cell infiltration,and exudation of plasma proteins and fibrin.Compared with LPS 0 h,at LPS 8 h,the oxygenation index and arterial blood pH were significantly decreased(P<0.001),while blood lactic acid and serum potassium were significantly increased(P<0.05);serum calcium and base excess were significantly decreased(P<0.05),and the lung injury score based on HE-stained lung sections was significantly increased(P<0.01).Conclusion The porcine ARDS model established by continuous LPS injection can dynamically simulate the pathophysiological characteristics and typical pathological manifestations of clinical septic ARDS,making it an effective tool to study the pathogenesis,prevention,and treatment strategies of septic ARDS.
9.Epidemiological and clinical characteristics of surveillance cases in a sentinel hospital for pertussis in Jiangxi Province in 2019
Hui WU ; Jie LIU ; Yuqin ZHAO ; Shicheng GUO ; Hairong WEN ; Jian LI
Shanghai Journal of Preventive Medicine 2025;37(6):507-510
ObjectiveTo analyze the epidemiological and clinical characteristics of surveillance cases in a sentinel hospital for pertussis in Jiangxi Province in 2019, and to provide corresponding references for the prevention and control of pertussis. MethodsCase investigation of pertussis was conducted among sentinel hospital surveillance cases, collecting their basic information, epidemiological characteristics, clinical characteristics, and other information. ResultsA total of 125 pertussis surveillance cases were investigated in 2019, including 73 clinically diagnosed cases (58.40%) and 52 confirmed cases (41.60%). The age of onset was mainly concentrated in children under 5 years old (108 cases, 86.40%), with the largest number of cases in infants aged less than 1-year-old (48 cases, 38.40%). Most cases had a history of receiving pertussis vaccine before onset (110 cases, 88.00%), and the intervals between the onset date and the date of last dose of pertussis vaccine in the 1‒2 doses group were significantly shorter than that in the 3‒4 doses group (U=-5.990, P<0.001). Probable household transmission of pertussis was found in 3 cases. All cases had cough symptoms, mainly manifested as whooping cough (77 cases, 61.60%), in addition to other main clinical manifestations, such as fever (76 cases, 60.80%), vomiting (30 cases, 24.00%), conjunctival congestion (27 cases, 21.60%), and inspiratory whoop (16 cases, 12.80%). A total of 73 cases (58.40%) experienced complications, including 1 death case. All the cases had multiple medical visit experiences before this visit, with an interval of 2 (0,3) days between the onset date and the first visit date. The misdiagnosis rate at the first medical visit was 88.00% (110/125), and the misdiagnosis rate of the first visit in secondary and primary hospitals was significantly higher than that in tertiary hospitals, exhibiting a statistically significant difference (χ2=21.582, P<0.001). ConclusionThe clinical symptoms of pertussis cases are often atypical, and the first diagnosis is prone to misdiagnosis, so it’s necessary to further strengthen the early diagnosis capabilities for pertussis cases in healthcare institutions, especially in the primary healthcare institutions.
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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