1.Effects of SPBC1604.04 Gene Deletion on Mitotic Cell Dynamics in Schizosaccharomyces pombe
Jia-Ni XU ; Jia-Yi HE ; Lang-Lin ZHENG ; Shu-Rong HE ; Shuai MA ; Xiang DING ; Yi-Ling HOU
Progress in Biochemistry and Biophysics 2026;53(5):1471-1484
ObjectiveMitochondria are not only the central organelles responsible for cellular energy metabolism but also play essential roles in regulating cell cycle progression and cytoskeletal dynamics. In recent years, accumulating evidence has demonstrated that mitochondrial homeostasis is closely associated with mitotic progression and cytokinesis. Schizosaccharomyces pombe serves as a classical and well-established model organism. Because its cell cycle regulatory mechanisms are highly conserved throughout evolution, its genetic background is clearly defined, and experimental manipulation is efficient and convenient, it has been extensively applied in studies of cell growth, division, and reproductive mechanisms. The SPBC1604.04 gene encodes a previously uncharacterized mitochondrial carrier protein in Schizosaccharomyces pombe. This gene is located on chromosome II and spans 1 018 base pairs in length. It encodes a protein consisting of 238 amino acids with a predicted molecular mass of approximately 31.03 ku. Bioinformatic analysis predicts that this protein is responsible for the transport of thiamine pyrophosphate (TPP) into mitochondria. However, the effects of SPBC1604.04 gene deletion on mitotic cell dynamics under different temperature conditions have not been fully elucidated. MethodsThe SPBC1604.04 deletion strain of Schizosaccharomyces pombe was used as the experimental model. Fluorescent protein markers were constructed in the deletion background to label mitochondria, microtubules, actin, myosin, the nuclear envelope, and chromosomes. Live-cell imaging was performed using a TCS-SP8 laser scanning confocal microscope under normal temperature conditions (25℃) and heat stress conditions (37℃). Time-lapse microscopy was applied to dynamically monitor mitochondrial morphology and distribution, spindle assembly and elongation, chromosome segregation, as well as the formation and constriction of the actomyosin ring during cytokinesis. ImageJ software was used for quantitative measurements, including microtubule length during mitosis, spindle length at different mitotic stages, mitochondrial fluorescence intensity as an indicator of mitochondrial content, actomyosin ring length, nuclear envelope area, and chromosome segregation timing. Statistical analyses were conducted to compare phenotypic differences between the wild-type and SPBC1604.04 deletion strains at both temperature conditions. Through these analyses, we systematically investigated the impact of SPBC1604.04 deletion on mitotic cell dynamics in fission yeast under both normal physiological conditions and temperature stress. ResultsAt 25℃, compared with wild-type cells, the SPBC1604.04Δ strain exhibited a pronounced tendency toward mitochondrial fragmentation, accompanied by abnormal mitochondrial content and a significant reduction in mitochondrial fluorescence intensity. These observations suggest impaired mitochondrial homeostasis under normal growth conditions. In addition, the constriction time of actomyosin ring during cytokinesis was markedly prolonged, indicating that deletion of SPBC1604.04 affects the dynamics of the contractile machinery. However, no obvious defects were observed in spindle assembly, spindle elongation, or chromosome segregation. Under heat stress at 37℃, mitochondrial morphology in the SPBC1604.04Δ strain showed a tendency to recover toward a continuous tubular network structure. Mitochondrial content was restored, fluorescence intensity increased, and the constriction time of the actomyosin ring returned to levels comparable to those of wild-type cells. These results indicate that the mitotic defects observed at normal temperature are partially or fully alleviated under heat stress conditions. ConclusionThis study demonstrates that deletion of the SPBC1604.04 gene leads to abnormal mitochondrial content in Schizosaccharomyces pombe. The mitochondrial carrier protein SPBC1604.04 participates in regulating actomyosin ring constriction during mitosis but does not appear to be directly involved in the regulation of spindle dynamics or chromosome segregation. Our findings provide key experimental evidence for understanding the functional link between the SPBC1604.04 gene, mitochondrial homeostasis, and mitotic regulation.
2.Effects of SPBC1604.04 Gene Deletion on Mitotic Cell Dynamics in Schizosaccharomyces pombe
Jia-Ni XU ; Jia-Yi HE ; Lang-Lin ZHENG ; Shu-Rong HE ; Shuai MA ; Xiang DING ; Yi-Ling HOU
Progress in Biochemistry and Biophysics 2026;53(5):1471-1484
ObjectiveMitochondria are not only the central organelles responsible for cellular energy metabolism but also play essential roles in regulating cell cycle progression and cytoskeletal dynamics. In recent years, accumulating evidence has demonstrated that mitochondrial homeostasis is closely associated with mitotic progression and cytokinesis. Schizosaccharomyces pombe serves as a classical and well-established model organism. Because its cell cycle regulatory mechanisms are highly conserved throughout evolution, its genetic background is clearly defined, and experimental manipulation is efficient and convenient, it has been extensively applied in studies of cell growth, division, and reproductive mechanisms. The SPBC1604.04 gene encodes a previously uncharacterized mitochondrial carrier protein in Schizosaccharomyces pombe. This gene is located on chromosome II and spans 1 018 base pairs in length. It encodes a protein consisting of 238 amino acids with a predicted molecular mass of approximately 31.03 ku. Bioinformatic analysis predicts that this protein is responsible for the transport of thiamine pyrophosphate (TPP) into mitochondria. However, the effects of SPBC1604.04 gene deletion on mitotic cell dynamics under different temperature conditions have not been fully elucidated. MethodsThe SPBC1604.04 deletion strain of Schizosaccharomyces pombe was used as the experimental model. Fluorescent protein markers were constructed in the deletion background to label mitochondria, microtubules, actin, myosin, the nuclear envelope, and chromosomes. Live-cell imaging was performed using a TCS-SP8 laser scanning confocal microscope under normal temperature conditions (25℃) and heat stress conditions (37℃). Time-lapse microscopy was applied to dynamically monitor mitochondrial morphology and distribution, spindle assembly and elongation, chromosome segregation, as well as the formation and constriction of the actomyosin ring during cytokinesis. ImageJ software was used for quantitative measurements, including microtubule length during mitosis, spindle length at different mitotic stages, mitochondrial fluorescence intensity as an indicator of mitochondrial content, actomyosin ring length, nuclear envelope area, and chromosome segregation timing. Statistical analyses were conducted to compare phenotypic differences between the wild-type and SPBC1604.04 deletion strains at both temperature conditions. Through these analyses, we systematically investigated the impact of SPBC1604.04 deletion on mitotic cell dynamics in fission yeast under both normal physiological conditions and temperature stress. ResultsAt 25℃, compared with wild-type cells, the SPBC1604.04Δ strain exhibited a pronounced tendency toward mitochondrial fragmentation, accompanied by abnormal mitochondrial content and a significant reduction in mitochondrial fluorescence intensity. These observations suggest impaired mitochondrial homeostasis under normal growth conditions. In addition, the constriction time of actomyosin ring during cytokinesis was markedly prolonged, indicating that deletion of SPBC1604.04 affects the dynamics of the contractile machinery. However, no obvious defects were observed in spindle assembly, spindle elongation, or chromosome segregation. Under heat stress at 37℃, mitochondrial morphology in the SPBC1604.04Δ strain showed a tendency to recover toward a continuous tubular network structure. Mitochondrial content was restored, fluorescence intensity increased, and the constriction time of the actomyosin ring returned to levels comparable to those of wild-type cells. These results indicate that the mitotic defects observed at normal temperature are partially or fully alleviated under heat stress conditions. ConclusionThis study demonstrates that deletion of the SPBC1604.04 gene leads to abnormal mitochondrial content in Schizosaccharomyces pombe. The mitochondrial carrier protein SPBC1604.04 participates in regulating actomyosin ring constriction during mitosis but does not appear to be directly involved in the regulation of spindle dynamics or chromosome segregation. Our findings provide key experimental evidence for understanding the functional link between the SPBC1604.04 gene, mitochondrial homeostasis, and mitotic regulation.
3.Preoperative evaluation of lung function in patients with lung cancer using two-phase dual-energy CT perfusion imaging
Lifang LING ; Yizhen JIA ; Qinmin HAO ; Wenzheng XU ; Zhibo WANG ; Jun WANG ; Liang CHEN ; Mei YUAN
Chinese Journal of Clinical Thoracic and Cardiovascular Surgery 2026;33(01):79-86
Objective To explore the application value of dual-phase dual-energy CT (DECT) perfusion imaging in preoperative lung function assessment of lung cancer patients. Methods Data were collected from patients with stageⅠA non-small cell lung cancer who underwent surgical treatment in the Department of Thoracic Surgery, the First Affiliated Hospital of Nanjing Medical University, from November 2022 to June 2024. All patients underwent DECT perfusion imaging and pulmonary function testing (PFT) before surgery. PFT observation indicators included ventilation function indicators such as forced expiratory volume in one second (FEV1), forced vital capacity (FVC), 1-second rate (FEV1/FVC), maximal voluntary ventilation (MVV), and diffusion function indicators such as diffusing capacity for carbon monoxide (DLCO) and DLCO per liter of alveolar volume (DLCO/VA). The software eXamine was used to obtain quantitative parameters of DECT perfusion imaging, including volume parameters and perfusion parameters of both lungs and each lung lobe. The correlation between the volume parameters and perfusion parameters of both lungs and the ventilation and diffusion function indicators of the patients, as well as the differences in quantitative parameters of each lung lobe, was analyzed. Results The end-inspiration lung volume and biphasic volume difference were strongly positively correlated with FEV1 and FVC (r=0.636, r=0.682, r=0.614, r=0.624, P<0.001) and moderately positively correlated with MVV and DLCO (r=0.499, r=0.514, r=0.549, r=0.447, P<0.001); the end-expiration lung volume was weakly negatively correlated with DLCO/VA (r=−0.295, P=0.026); the volume ratio was positively correlated with FEV1, FVC, MVV, and MVV% (r=0.424, r=0.399, r=0.415, r=0.310, P<0.05); the end-inspiration iodine content was weakly positively correlated with DLCO/VA% (rs=0.292, P=0.030); the end-expiration iodine content was weakly positively correlated with FEV1, FVC, MVV, DLCO%, and DLCO/VA (r=0.307, r=0.299, r=0.295, r=0.366, r=0.320, P<0.05) and moderately positively correlated with DLCO (r=0.439, P<0.001); the end-inspiration iodine concentration was negatively correlated with FEV1, FVC, MVV, and MVV% (rs=−0.407, rs=−0.426, rs=−0.352, rs=−0.277, P<0.05); the end-expiratory phase iodine concentration was moderately positively correlated with DLCO/VA (r=0.403, P=0.002); both the iodine concentration difference and the iodine concentration ratio were moderately positively correlated with FEV1, FEV1%, FVC, MVV, MVV% (P<0.05). The lung volume and iodine concentration ratio values were both highest in the left upper lung lobe and lowest in the right middle lung lobe; the differences in lung volume, lung volume ratio, intrapulmonary iodine content, and intrapulmonary iodine concentration were all highest in the lower lobes of both lungs and lowest in the middle lobe of the right lung. Conclusion Dual-phase DECT perfusion imaging can accurately assess overall lung function and quantify regional lung function.
4.Simulation of Potential Suitable Habitats for the Tibetan Medicine"Zhi Da Sa Zeng"and Analysis on Influencing Factors
Zhiwei XU ; Xudong GUO ; Xiaohui MA ; Shouning JIA ; Jianwu SHEN ; Ling JIN
Chinese Journal of Information on Traditional Chinese Medicine 2025;32(10):7-13
Objective To investigate the spatial distribution patterns and environmental determinants of Lagotis brachystachya Maxim.,a keystone species in Tibetan medicine("Zhi Da Sa Zeng"),under contemporary climatic conditions in China;To provide references for the sustainable utilization of its resources and the ecological protection of alpine grassland areas.Methods Based on the maximum entropy model,the selected species distribution data and environmental factors were added to MaxEnt 4.3.1 software for modeling.The geographical detector was applied to quantify the factors influencing the spatial differentiation of the suitable areas,employing both factor detection and interaction detection functionalities.Additionally,an overlay analysis with land cover types was conducted to quantify the distribution characteristics of grassland within the potential suitable areas for Lagotis brachystachya Maxim..Results Under the current climatic conditions,dominant environmental drivers included elevation,monthly average temperature difference between day and night,average precipitation in June,wind speed in September,solar radiation in August,average precipitation in May,average precipitation in October,among which elevation demonstrated the strongest explanatory power(q=0.37)in habitat suitability analysis.The model prediction results showed that the potential suitable area for Lagotis brachystachya Maxim.was 5.31×105 km2.Considering the type of surface coverage,the main suitable habitat for Lagotis brachystachya Maxim.was grassland,with an area of 4.34×105 km2.The high suitable grassland of areas were mainly distributed in Qinghai Province(Yushu Tibetan Autonomous Prefecture,Huangnan Tibetan Autonomous Prefecture,Golog Tibetan Autonomous Prefecture,Hainan Tibetan Autonomous Prefecture,Haibei Tibetan Autonomous Prefecture),Sichuan Province(Ganzi Tibetan Autonomous Prefecture,Aba Qiang Autonomous Prefecture),Xizang Autonomous Region(Naqu City,Shigatse City,Changdu City),and Gansu Province(Gannan Tibetan Autonomous Prefecture).Conclusion This study can provide references for the protection of wild resources and the selection of domestication and cultivation areas for Lagotis brachystachya Maxim..
5.Study on Uncertainty and Scalability in Single-Analysis Salivary Peptidome Studies
Xiu-Feng FANG ; Bing-Jia CUI ; Jin-Ling XU ; Yong WANG
Chinese Journal of Analytical Chemistry 2025;53(11):1820-1827,中插1-中插3
Nano liquid chromatography-high resolution tandem mass spectrometry(LC-HRMS/MS)is widely used for body fluid peptidome analysis,yet the impact of replicate analyses remains overlooked.Using salivary peptidome,in this work,10 replicate analyses of the same sample were conducted.It was found that although m/z and molecular weight ranges were consistent across replicates,single runs identified only 348-576 unique peptides from 32-39 degraded proteins.Merging all replicates revealed 1237 peptides from 77 proteins,a 2.5 folds increase in peptides and 2 folds increase in proteins.Instrument stability was confirmed via intensity/retention time of 12 peptides.Merged peptides primarily derived from high-abundance proteins(e.g.,Statherin,PRP1/2).Analysis of 20 peptides showed that the some peptides were detected in single analysis but confidence varying(19%-99%),low-confidence peptides(<95%)exceeded 95%after replicate.signal intensity alone didn't determine confidence and peptides spanning the sequence region between the longest and the shortest detected fragments could be identified.The above findings suggested that single-run LC-MS peptidomics analysis carried inherent false negatives and uncertainties.However,by integrating the results of a single analysis with the mechanism of enzymatic hydrolysis for endogenous peptides,it was possible to make reasonable inferences and extrapolations regarding peptides derived from highly abundant degraded proteins.
6.Specific effect of inserted sham acupuncture and its impact on the estimation of acupuncture treatment effect in randomized controlled trials: A systematic survey.
Xiao-Chao LUO ; Jia-Li LIU ; Ming-Hong YAO ; Ye-Meng CHEN ; Arthur Yin FAN ; Fan-Rong LIANG ; Ji-Ping ZHAO ; Ling ZHAO ; Xu ZHOU ; Xiao-Ying ZHONG ; Jia-Hui YANG ; Bo LI ; Ying ZHANG ; Xin SUN ; Ling LI
Journal of Integrative Medicine 2025;23(6):630-640
BACKGROUND:
The use of inserted sham acupuncture as a placebo in randomized controlled trials (RCTs) is controversial, because it may produce specific effects that cause an underestimation of the effect of acupuncture treatment.
OBJECTIVE:
This systematic survey investigates the magnitude of insert-specific effects of sham acupuncture and whether they affect the estimation of acupuncture treatment effects.
SEARCH STRATEGY:
PubMed, Embase and Cochrane Central Register of Controlled Trials were searched to identify acupuncture RCTs from their inception until December 2022.
INCLUSION CRITERIA:
RCTs that evaluated the effects of acupuncture compared to sham acupuncture and no treatment.
DATA EXTRACTION AND ANALYSIS:
The total effect measured for an acupuncture treatment group in RCTs were divided into three components, including the natural history and/or regression to the mean effect (controlled for no-treatment group), the placebo effect, and the specific effect of acupuncture. The first two constituted the contextual effect of acupuncture, which is mimicked by a sham acupuncture treatment group. The proportion of acupuncture total effect size was considered to be 1. The proportion of natural history and/or regression to the mean effect (PNE) and proportional contextual effect (PCE) of included RCTs were pooled using meta-analyses with a random-effect model. The proportion of acupuncture placebo effect was the difference between PCE and PNE in RCTs with non-inserted sham acupuncture. The proportion of insert-specific effect of sham acupuncture (PIES) was obtained by subtracting the proportion of acupuncture placebo effect and PNE from PCE in RCTs with inserted sham acupuncture. The impact of PIES on the estimation of acupuncture's treatment effect was evaluated by quantifying the percentage of RCTs that the effect of outcome changed from no statistical difference to statistical difference after removing PIES in the included studies, and the impact of PIES was externally validated in other acupuncture RCTs with an inserted sham acupuncture group that were not used to calculate PIES.
RESULTS:
This analysis included 32 studies with 5492 patients. The overall PNE was 0.335 (95% confidence interval [CI], 0.255-0.415) and the PCE of acupuncture was 0.639 (95% CI, 0.567-0.710) of acupuncture's total effect. The proportional contribution of the placebo effect to acupuncture's total effect was 0.191, and the PIES was 0.189. When we modeled the exclusion of the insert-specific effect of sham acupuncture, the acupuncture treatment effect changed from no difference to a significant difference in 45.45% of the included RCTs, and in 40.91% of the external validated RCTs.
CONCLUSION
The insert-specific effect of sham acupuncture in RCTs represents 18.90% of acupuncture's total effect and significantly affects the evaluation of the acupuncture treatment effect. More than 40% of RCTs that used inserted sham acupuncture would draw different conclusions if the PIES had been controlled for. Considering the impact of the insert-specific effect of sham acupuncture, caution should be taken when using inserted sham acupuncture placebos in RCTs. Please cite this article as: Luo XC, Liu JL, Yao MH, Chen YM, Fan AY, Liang FR, Zhao JP, Zhao L, Zhou X, Zhong XY, Yang JH, Li B, Zhang Y, Sun X, Li L. Specific effect of inserted sham acupuncture and its impact on the estimation of acupuncture treatment effect in randomized controlled trials: A systematic survey. J Integr Med. 2025; 23(6):630-640.
Acupuncture Therapy/methods*
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Humans
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Randomized Controlled Trials as Topic
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Placebo Effect
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Placebos
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Treatment Outcome
7.Analysis of Serum Metabolic Biomarkers in Adult Patients with Kashin-Beck Disease and Degenerative Osteoarthritis in Qinghai Province.
Jia le XU ; Qiang LI ; Chuan LU ; Xin ZHOU ; Yan Mei ZHAO ; Jian Ling WANG ; Ji Quan LI ; Li MA ; Zhi Jun ZHAO ; Ke Wen LI
Biomedical and Environmental Sciences 2025;38(9):1173-1177
8.Expert Consensus on the Ethical Requirements for Generative AI-Assisted Academic Writing
You-Quan BU ; Yong-Fu CAO ; Zeng-Yi CHANG ; Hong-Yu CHEN ; Xiao-Wei CHEN ; Yuan-Yuan CHEN ; Zhu-Cheng CHEN ; Rui DENG ; Jie DING ; Zhong-Kai FAN ; Guo-Quan GAO ; Xu GAO ; Lan HU ; Xiao-Qing HU ; Hong-Ti JIA ; Ying KONG ; En-Min LI ; Ling LI ; Yu-Hua LI ; Jun-Rong LIU ; Zhi-Qiang LIU ; Ya-Ping LUO ; Xue-Mei LV ; Yan-Xi PEI ; Xiao-Zhong PENG ; Qi-Qun TANG ; You WAN ; Yong WANG ; Ming-Xu WANG ; Xian WANG ; Guang-Kuan XIE ; Jun XIE ; Xiao-Hua YAN ; Mei YIN ; Zhong-Shan YU ; Chun-Yan ZHOU ; Rui-Fang ZHU
Chinese Journal of Biochemistry and Molecular Biology 2025;41(6):826-832
With the rapid development of generative artificial intelligence(GAI)technologies,their widespread application in academic research and writing is continuously expanding the boundaries of sci-entific inquiry.However,this trend has also raised a series of ethical and regulatory challenges,inclu-ding issues related to authorship,content authenticity,citation accuracy,and accountability.In light of the growing involvement of AI in generating academic content,establishing an open,controllable,and trustworthy ethical governance framework has become a key task for safeguarding research integrity and maintaining trust within the academic community.This expert consensus outlines ethical requirements across key stages of AI-assisted academic writing-including topic selection,data management,citation practices,and authorship attribution.It aims to clarify the boundaries and ethical obligations surrounding AI use in academic writing,ensuring that technological tools enhance efficiency without compromising in-tegrity.The goal is to provide guidance and institutional support for building a responsible and sustainable research ecosystem.
9.Simulation of Potential Suitable Habitats for the Tibetan Medicine"Zhi Da Sa Zeng"and Analysis on Influencing Factors
Zhiwei XU ; Xudong GUO ; Xiaohui MA ; Shouning JIA ; Jianwu SHEN ; Ling JIN
Chinese Journal of Information on Traditional Chinese Medicine 2025;32(10):7-13
Objective To investigate the spatial distribution patterns and environmental determinants of Lagotis brachystachya Maxim.,a keystone species in Tibetan medicine("Zhi Da Sa Zeng"),under contemporary climatic conditions in China;To provide references for the sustainable utilization of its resources and the ecological protection of alpine grassland areas.Methods Based on the maximum entropy model,the selected species distribution data and environmental factors were added to MaxEnt 4.3.1 software for modeling.The geographical detector was applied to quantify the factors influencing the spatial differentiation of the suitable areas,employing both factor detection and interaction detection functionalities.Additionally,an overlay analysis with land cover types was conducted to quantify the distribution characteristics of grassland within the potential suitable areas for Lagotis brachystachya Maxim..Results Under the current climatic conditions,dominant environmental drivers included elevation,monthly average temperature difference between day and night,average precipitation in June,wind speed in September,solar radiation in August,average precipitation in May,average precipitation in October,among which elevation demonstrated the strongest explanatory power(q=0.37)in habitat suitability analysis.The model prediction results showed that the potential suitable area for Lagotis brachystachya Maxim.was 5.31×105 km2.Considering the type of surface coverage,the main suitable habitat for Lagotis brachystachya Maxim.was grassland,with an area of 4.34×105 km2.The high suitable grassland of areas were mainly distributed in Qinghai Province(Yushu Tibetan Autonomous Prefecture,Huangnan Tibetan Autonomous Prefecture,Golog Tibetan Autonomous Prefecture,Hainan Tibetan Autonomous Prefecture,Haibei Tibetan Autonomous Prefecture),Sichuan Province(Ganzi Tibetan Autonomous Prefecture,Aba Qiang Autonomous Prefecture),Xizang Autonomous Region(Naqu City,Shigatse City,Changdu City),and Gansu Province(Gannan Tibetan Autonomous Prefecture).Conclusion This study can provide references for the protection of wild resources and the selection of domestication and cultivation areas for Lagotis brachystachya Maxim..
10.Experimental study on alternative method of local lymph node assay using bromodeoxyuridine with flow cytometry(LLNA:BrdU-FCM)for skin sensitization evaluation of cosmetics
Xiao-jun LYU ; Ju ZHANG ; Sen WU ; Xiao-ling XU ; Meng-ting SHI ; Jin-jing XU ; Wang-ping PAN ; Jia-te SHEN ; Kai-yong HE
Chinese Pharmacological Bulletin 2025;41(4):793-799
Aim To establish and evaluate an alternative meth-od for detecting skin sensitization of cosmetics based on local lymph node assay using bromodeoxyuridine(BrdU)with flow cytometry(FCM).Methods(1)25%hexyl cinnamic alde-hyde(HCA)was chosen as a positive control with an acetone:olive oil(4∶1,V/V,AOO)mixture as a vehicle control for the experiment.The dorsal sides of both ears of mice were treated with test solutions on day 1,day 2,and day 3.Brdu solution was injected inter-peritoneally on day 5.On day 6,the bilateral ears and mandibular lymph nodes were excised,and the number of Brdu positive cells was measured by flow cytometry.The stim-ulation index(SI)was calculated to identify whether it was ≥3,in order to establish the method of LLNA:Brdu-FCM.(2)BrdU-FCM test was conducted using a blind method with the fif-teen reference substances listed in OECD TG429 whose skin sensitization potentials were known.The test substances were dissolved in AOO,N,N-dimethylformamide(DMF)or dimeth-yl sulfoxide(DMSO)at three different concentrations.Tests were performed the same as above.SI and EC2.7 were calculat-ed to evaluate whether the test substance was categorized as a skin sensitizer.The reliability and accuracy of the method were validated by comparing the classification of test substances with that in OECD TG429.Results The SI for 25%HCA was 3.9,showing positive in the skin sensitization test.It demonstrated that the LLNA:Brdu-FCM test method was properly implemen-ted.Nine test substances(2,4-dinitrochlorobenzene,4-pheny-lenediamine,cobalt chloride,2-mercaptobenzothiazole,hexyl-cinnamaldehyde,eugenol,phenyl benzoate,cinnamic alcohol,imidazolidinyl urea)were positive,and six test substances(methyl methacrylate,chlorobenzene,isopropanol,lactic acid,methyl salicylate,salicylic acid)were negative.The method was evaluated with sensitivity of 90%,specificity of 100%,positive prediction rate of 100%,negative prediction rate of 83%,false positive rate of 0%,false negative rate of 17%and accuracy of 93%.The LLNA:BrdU-FCM assay could correctly categorize the test substances that were skin sensitizers or non-sensitizers.Conclusion The LLNA:BrdU-FCM assay appears to be a relia-ble predictor of skin sensitization protential of chemicals,and it is expected to an alternative method for identifying skin sensitization as a supplementary in safety evaluation of cosmetic ingredient.

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