1.Caffeoylquinic acids from Erigeron breviscapus ameliorates cognitive impairment and mitochondrial dysfunction in AD by activating PINK1/Parkin-mediated mitophagy.
Yuan-Zhu PU ; Hai-Feng CHEN ; Xin-Yi WANG ; Can SU
China Journal of Chinese Materia Medica 2025;50(14):3969-3979
This study aimed to investigate the effects of caffeoylquinic acids from Erigeron breviscapus(EBCQA) on cognitive impairment and mitochondrial dysfunction in Alzheimer's disease(AD), and to explore its underlying mechanisms. The impacts of EBCQA on paralysis, β-amyloid(Aβ) oligomerization, and mRNA expression of mitophagy-related genes [PTEN-induced putative kinase 1(PINK1) homolog-encoding gene pink-1, Parkin homolog-encoding gene pdr-1, Bcl-2 interacting coiled-coil protein 1(Beclin 1) homolog-encoding gene bec-1, microtubule-associated protein 1 light chain 3(LC3) homolog-encoding gene lgg-1, autophagic adapter protein 62(p62) homolog-encoding gene sqst-1] were examined in the AD Caenorhabditis elegans CL4176 model, along with mitochondrial functions including adenosine triphosphate(ATP) content, enzyme activities of mitochondrial respiratory chain complexes Ⅰ,Ⅲ, and Ⅳ, and mitochondrial membrane potential. Additionally, the effects of EBCQA on the green fluorescent protein(GFP)/red fluorescent protein from Discosoma sp.(DsRed) ratio, the expression of phosphatidylethanolamine-modified and GFP-labeled LGG-1(PE-GFP::LGG-1)/GFP-labeled LGG-1(GFP::LGG-1), and GFP-labeled SQST-1(GFP::SQST-1) proteins were investigated in transgenic C. elegans strains. The effect of EBCQA on paralysis was further evaluated after RNA interference(RNAi)-mediated suppression of the pink-1 and pdr-1 genes in CL4176 strain. An AD rat model was established through intraperitoneal injection of D-galactose and intragastric administration of aluminum trichloride. The effects of β-nicotinamide mononucleotide(NMN) and EBCQA on learning and memory ability, neuronal morphology, mitophagy occurrence, mitophagy-related protein expression(PINK1, Parkin, Beclin 1, LC3-Ⅱ/LC3-Ⅰ, p62), and mitochondrial functions(ATP content; enzyme activities of mitochondrial respiratory chain complexes Ⅰ, Ⅲ, and Ⅳ; mitochondrial membrane potential) were investigated in this AD rat model. The results showed that EBCQA delayed paralysis onset in the CL4176 strain, reduced Aβ oligomer formation, and upregulated the mRNA expression levels of lgg-1, bec-1, pink-1, and pdr-1, while downregulating sqst-1 mRNA expression. EBCQA also enhanced ATP content, mitochondrial membrane potential, and the activities of mitochondrial respiratory chain complexes Ⅰ, Ⅲ, and Ⅳ. Furthermore, EBCQA improved the PE-GFP::LGG-1/GFP::LGG-1 ratio, reduced GFP::SQST-1 expression, and decreased the GFP/DsRed ratio. Notably, the ability of EBCQA to delay paralysis was significantly reduced following RNAi-mediated suppression of pink-1 and pdr-1 in CL4176 strain. In AD rats, the administration of NMN or EBCQA significantly improved learning and memory, restored neuronal morphology in the hippocampus, increased autophagosome numbers, and upregulated the expression of PINK1, Parkin, Beclin 1, and the LC3-Ⅱ/LC3-Ⅰ ratio, while reducing p62 expression. Additionally, the treatment with NMN or EBCQA both elevated ATP content, mitochondrial respiratory chain complex Ⅰ, Ⅲ, and Ⅳ activities, and mitochondrial membrane potential in the hippocampus. The above findings indicate that EBCQA improves cognitive impairment and mitochondrial dysfunction in AD, possibly through activation of PINK1/Parkin-mediated mitophagy.
Animals
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Alzheimer Disease/psychology*
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Mitophagy/drug effects*
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Mitochondria/genetics*
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Caenorhabditis elegans/metabolism*
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Ubiquitin-Protein Ligases/genetics*
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Cognitive Dysfunction/physiopathology*
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Rats
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Protein Kinases/genetics*
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Humans
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Male
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Disease Models, Animal
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Caenorhabditis elegans Proteins/genetics*
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Drugs, Chinese Herbal/administration & dosage*
2.Beneficial Effects of Dendrobium officinale Extract on Insomnia Rats Induced by Strong Light and Noise via Regulating GABA and GABAA Receptors.
Heng-Pu ZHOU ; Jie SU ; Ke-Jian WEI ; Su-Xiang WU ; Jing-Jing YU ; Yi-Kang YU ; Zhuang-Wei NIU ; Xiao-Hu JIN ; Mei-Qiu YAN ; Su-Hong CHEN ; Gui-Yuan LYU
Chinese journal of integrative medicine 2025;31(6):490-498
OBJECTIVE:
To explore the therapeutic effects and underlying mechanisms of Dendrobium officinale (Tiepi Shihu) extract (DOE) on insomnia.
METHODS:
Forty-two male Sprague-Dawley rats were randomly divided into 6 groups (n=7 per group): normal control, model control, melatonin (MT, 40 mg/kg), and 3-dose DOE (0.25, 0.50, and 1.00 g/kg) groups. Rats were raised in a strong-light (10,000 LUX) and -noise (>80 db) environment (12 h/d) for 16 weeks to induce insomnia, and from week 10 to week 16, MT and DOE were correspondingly administered to rats. The behavior tests including sodium pentobarbital-induced sleep experiment, sucrose preference test, and autonomous activity test were used to evaluate changes in sleep and emotions of rats. The metabolic-related indicators such as blood pressure, blood viscosity, blood glucose, and uric acid in rats were measured. The pathological changes in the cornu ammonis 1 (CA1) region of rat brain were evaluated using hematoxylin and eosin staining and Nissl staining. Additionally, the sleep-related factors gamma-aminobutyric acid (GABA), glutamate (GA), 5-hydroxytryptamine (5-HT), and interleukin-6 (IL-6) were measured using enzyme linked immunosorbent assay. Finally, we screened potential sleep-improving receptors of DOE using polymerase chain reaction (PCR) array and validated the results with quantitative PCR and immunohistochemistry.
RESULTS:
DOE significantly improved rats' sleep and mood, increased the sodium pentobarbital-induced sleep time and sucrose preference index, and reduced autonomic activity times (P<0.05 or P<0.01). DOE also had a good effect on metabolic abnormalities, significantly reducing triglyceride, blood glucose, blood pressure, and blood viscosity indicators (P<0.05 or P<0.01). DOE significantly increased the GABA content in hippocampus and reduced the GA/GABA ratio and IL-6 level (P<0.05 or P<0.01). In addition, DOE improved the pathological changes such as the disorder of cell arrangement in the hippocampus and the decrease of Nissel bodies. Seven differential genes were screened by PCR array, and the GABAA receptors (Gabra5, Gabra6, Gabrq) were selected for verification. The results showed that DOE could up-regulate their expressions (P<0.05 or P<0.01).
CONCLUSION
DOE demonstrated remarkable potential for improving insomnia, which may be through regulating GABAA receptors expressions and GA/GABA ratio.
Animals
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Dendrobium/chemistry*
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Rats, Sprague-Dawley
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Male
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Sleep Initiation and Maintenance Disorders/blood*
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Plant Extracts/therapeutic use*
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Receptors, GABA-A/metabolism*
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Noise/adverse effects*
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Light/adverse effects*
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gamma-Aminobutyric Acid/metabolism*
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Sleep/drug effects*
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Rats
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Receptors, GABA/metabolism*
3.Dynamic changes of neutrophil extracellular traps(NETs)release and microcirculatory disorders associated with high altitude pulmonary edema after high altitude hypoxia exposure
Hong SU ; Qian CHENG ; Yaxuan WANG ; Chongyang DAI ; Fubang ZHAO ; Xiaoyan PU
Chinese Journal of Clinical Pharmacology and Therapeutics 2025;30(6):732-740
AIM:To compare the formation and release of neutrophil extracellular traps(NETs)af-ter exposure to the high-altitude hypoxic environ-ment for different periods,and their relationship with the dynamic changes of microcirculatory disor-ders associated with pulmonary edema.METH-ODS:SD rats were raised under normoxic condi-tions at an altitude of 400 m and under hypoxic conditions at an altitude of 4 200 m.The rats raised under hypoxic conditions at an altitude of 4 200 m for 7 days were returned to normoxic con-ditions at 400 m to observe the changes in physio-logical and pathological indicators of the rats.The dynamic changes of neutrophil extracellular traps(NETs)release and microcirculatory disorders relat-ed to pulmonary edema after high-altitude hypoxia exposure and after returning to the plain were ex-plored by blood routine determination,rat arterial blood gas analysis,ELISA experiment,lung water content determination,H&E staining,and immuno-histochemical staining.RESULTS:In the hypoxic en-vironment at 4 200 m,rats exhibited significant re-ductions in arterial oxygen saturation(SaO2)and partial pressure of oxygen(PO2)(P<0.01),accompa-nied by a marked increase in lung-tissue water con-tent(P<0.01).The complete blood count revealed elevated levels of red blood cells,white blood cells,lymphocytes,and neutrophils(P<0.01).In addition,the formation and release of NETs in neutrophils in-creased,accompanied by an aggravation of the in-flammatory response.After returning to the low-al-titude normoxic area at 400 m,the above indica-tors gradually returned to normal levels on the 7th day.Pathological changes such as alveolar epitheli-al cell shedding and inflammatory cell infiltration were observed in the lung tissues of rats in the high-altitude area,and the pathological changes were restored after returning to the low-altitude normoxic environment.CONCLUSION:The release of NETs from neutrophils is closely related to the re-covery of pulmonary edema and pulmonary ede-ma-related microcirculatory disorders after high-al-titude hypoxia exposure.
4.Comparative study on diagnostic efficacy of 3 Tesla magnetic resonance imaging with zero echo time versus high resolution computed tomography for pulmonary nodule detection and Lung-RADS classification in sub-health populations
Li-jun YANG ; Kai SU ; Peng-fei YANG ; Ming-xia JIANG ; Rong-ping SHI ; Huan-pu GE ; Qiong WU
Chinese Medical Equipment Journal 2025;46(9):52-59
Objective To explore the efficacy differences between 3 Tesla magnetic resonance imaging with zero echo time(3T MRI ZTE)and high resolution computed tomography(HRCT)in the detection of pulmonary nodules and the classification diagnosis of the lung imaging reporting and data system(Lung-RADS)in sub-health populations.Methods Clinical and imaging data of 93 patients with pulmonary nodules(126 nodules in total)admitted to some hospital from July to December 2023 were retrospectively analyzed.The 126 nodules were categorized into a benign nodule group(n=51)and a malignant nodule group(n=75)using pathological findings as the gold standard.All the patients underwent examinations by 3T MRI ZTE and HRCT to compare the detection rates of the two measures for pulmonary nodules;the missed and misdiagnosis rates of 3T MRI ZTE,HRCT and Lung-RADS grading were contrasted with the postoperative pathological diagnosis results as the gold standard;comparison analyses of 3T MRI ZTE signs and HRCT signs were performed between the two groups and the patients with different Lung-RADS grades;3T MRI ZTE,HRCT and Lung-RADS grading were compared with the receiver operating characteristic(ROC)curve in terms of diagnosis efficacy for pulmonary nodules,and the consistency analysis was carried out.Results No discernible statistical variation was observed in the detection rates of pulmonary nodules between 3T MRI ZTE and HRCT(P>0.05).Lung-RADS grading had the highest rates of missed diagnosis and misdiagnosis,and 3T MRI ZTE and HRCT had similar detection rates.The malignant nodule group was different from the benign nodule group in the 3T MRI ZTE and HRCT signs in terms of lesion size,spiculation sign,lobulation sign,calcifica-tion,pleural indentation sign,cavity sign,boundary and bronchial cut-off sign,with the differences being statistically signi-ficant(all P<0.05).For the patients of Lung-RADS grade 3,the 3T MRI ZTE and HRCT signs had significant differences in terms of lesion size,spiculation sign,lobulation sign,calcification,pleural indentation sign,cavity sign and bronchial cut-off sign(all P<0.05).For the patients of Lung-RADS grade 4A,the 3T MRI ZTE and HRCT signs had significant differen-ces in terms of lesion size,calcification,boundary and bronchial cut-off sign(all P<0.05).For the patients of Lung-RADS grade 4B,the 3T MRI ZTE and HRCT signs had significant differences in terms of lesion size and calcification(all P<0.05).For the patients of Lung-RADS grade 4X,there were no significant differences found between the 3T MRI ZTE and HRCT signs(all P>0.05).HRCT had the highest sensitivity,specificity,accuracy,AUC value,predictive values and Kappa value for benign and malignant nodules,3T MRI ZTE had the values slightly lower than those of HRCT,and Lung-RADS grading had the lowest values when compared with HRCT and 3T MRI ZTE.Conclusion HRCT and 3T MRI ZTE are complementary for the evaluation of pulmonary nodules,and the differences in imaging signs between them show graded dependence.3T MRI ZTE and HRCT have no significant differences in the detection rate of pulmonary nodules,while HRCT gains advanta-ges in differentiating benign and malignant pulmonary nodules,and references are provided for the screening and clinical early diagnosis of pulmonary nodules.[Chinese Medical Equipment Journal,2025,46(9):52-59]
5.Effects of Wheat Grain Moxibustion on Hippocampal ERK/CREB-BDNF/TrkB Signaling Pathway and Neurotransmitters in Perimenopausal Depressive Disorder Rats
Hong SU ; Shengyong SU ; Jing LI ; Pu YANG ; Xi ZHANG ; Tian WANG ; Qiongxiao WANG
Chinese Journal of Information on Traditional Chinese Medicine 2025;32(8):98-104
Objective To observe the effects of wheat grain moxibustion on the hippocampal ERK/CREB-BDNF/TrkB signaling pathway and neurotransmitters in rats with perimenopausal depressive disorder(PDD);To explore its mechanism in treating PDD.Methods Totally 24 female SD rats were randomly divided into sham-operation group,model group,Western medicine group and wheat grain moxibustion group,with 6 rats in each group.The PDD rat model was established by bilateral ovariectomy and chronic unpredictable mild stress.The wheat grain moxibustion group received moxibustion at the"Zhongwan","Xiawan","Qihai","Guanyuan"acupoints,with a conical moxa cone for intervention,6 cones per acupoint;the Western medicine group was given fluoxetine hydrochloride solution 1.8 mg/kg by gavage,once a day,for consecutive 21 d.Before and after modeling and after intervention,the body mass,sucrose water preference rate and immobility time in the forced swimming test of the rats were recorded;Transmission electron microscopy was used to observe the synaptic structure in hippocampal tissue;ELISA was used to detect the expressions of 5-HT,GABA and Glu in hippocampal tissue;Western blot was used to detect the expressions of ERK,p-ERK,CREB,p-CREB,BDNF and TrkB proteins in hippocampal tissue.Results Compared with the sham-operation group,the body mass and sucrose water preference rate of the model group decreased,and the immobility time in the forced swimming test was prolonged(P<0.01);the number of synaptic vesicles in hippocampus decreased,the thickness of the postsynaptic density decreased,the aggregation of transduction-related proteins decreased,the synaptic cleft increased;the contents of 5-HT and GABA in hippocampal tissue decreased,the content of Glu increased,and the expressions of p-ERK,p-CREB,BDNF and TrkB proteins decreased(P<0.01).Compared with the model group,the body mass and sucrose water preference rate of the rats in Western medicine group and wheat grain moxibustion group increased,and the immobility time in the forced swimming test was shortened(P<0.01);the area of the postsynaptic density in the hippocampus increased,the synaptic cleft reduced,the contents of 5-HT and GABA in hippocampal tissue increased,the content of Glu decreased,and the expressions of p-ERK,p-CREB,BDNF and TrkB proteins increased(P<0.01).Conclusion Wheat grain moxibustion can effectively alleviate depressive-like behavior in PDD rats,and its mechanism may be related to regulating neurotransmitter expressions and mediating the ERK/CREB-BDNF/TrkB signaling pathway,thereby regulating hippocampal neuroplasticity.
6.Effects of Wuzi Yanzong Pills on subacute aging-induced testicular trauma and AMPK/mTOR pathway in rats
Sheng MU ; Hui-ming MA ; Hong HUI ; Jing PU ; Xiao SU
Chinese Traditional Patent Medicine 2025;47(5):1467-1476
AIM To investigate the effects of Wuzi Yanzong Pills on subacute aging-induced testicular trauma and AMPK/mTOR pathway in rats.METHODS Rat models of subacute aging were induced by 8-week subcutaneous injection of D-gal(200 mg/kg)into the rat neck,followed by their random assignment into the model group,the metformin group(0.3 g/kg)and the low-dose and high-dose Wuzi Yanzong Pills groups(0.54,2.16 g/kg),with 9 rats in each group,in contrast to the 8 intact rats of the normal group.And the corresponding drug was given by gavage for 4 weeks after modeling,after which the rats had their levels of serum T,FSH,SOD,LH,8-OHdG and MDA detected by ELISA;their pathological changes of testes observed by HE and β-galactosidase staining;and their expressions of aging-related proteins(p16,p21,p53),testicle secretory function-related proteins(CYP11A1,HSD17B3,STAR),autophagy-related proteins(p62,ATG5,Beclin-1,LC3B)and AMPK/mTOR pathway-related protein detected by Western blot and immunohistochemistry.RESULTS Compared with the normal group,the model group displayed morphologically smaller testes and body surface;dry hair;overall atrophic testicular tissue structure;increased testicular protein expressions of γ-H2AX,p16,p21 andβ-galactosidase(P<0.05,P<0.01);and decreased p53 protein expression(P<0.05);suggesting the modeling success.Compared with the model group,the high-dose Wuzi Yanzong Pills group shared decreased levels of serum 8-OHdG,MDA,FSH and LH(P<0.01);increased levels of SOD and T(P<0.01);improved sperm damage and almost morphologically normal testicular tissue;decreased testicular protein expressions of p16,p21,p53,p62 and p-mTOR(P<0.01);and increased protein expressions of CYP11A1,HSD17B3,STAR,ATG5,Beclin-1,LC3B and p-AMPK(P<0.01).CONCLUSION Wuzi Yanzong Pills can improve the subacute aging-induced testicular injury and testicular function in rats by reducing their oxidative stress through improving their autophagy level and testicle antioxidant capacity.
7.Bioinformatics analysis and experimental verification of disulfidptosis-related genes in vascular dementia
Jin-zhi ZHANG ; Wei CHEN ; Gui-feng ZHUO ; Er-wei HAO ; Xiao-min ZHU ; Yu-lan FU ; Shan-shan PU ; Ming-yang SU ; Lin WU
Chinese Pharmacological Bulletin 2025;41(3):514-520
Aim To examine the pathogenesis of disul-fide death gene in vascular dementia(VD)by bioin-formatics analysis of disulfide death differentially ex-pressed genes(DEGs)combined with experimental verification.Methods The death DEGs of disulfide were screened and their correlation was analyzed.The VD patients data in the data set were analyzed by clus-tering and typing and gene set variation.The clustering risk of DEGs was tested with a nomogram model,and the optimal learning model was predicted.After the es-tablishment of VD rat model,water maze test,HE stai-ning and RT-qPCR detection were performed to verify the results of health information.Results Four DEGs including SLC7A11 were obtained,which had antago-nistic or synergistic interaction with each other.The genetic data could be divided into two subtypes with significant differences.After typing,VD disulfide DEGs were mainly concentrated in GnRH signaling pathways.The accuracy of the nomogram prediction model was high.Generalized linear was the best ma-chine learning model.Compared with the sham opera-tion group,the escape latency of rats in the model group was prolonged,the number of crossing platforms decreased,the relative mRNA expression levels of Slc3a2 and Slc7a11 decreased,and LRPPRC in-creased.Conclusions SLC7A11 and other disulfide death DEGs and its related GnRH signaling pathway may be an important part of the pathogenesis of VD di-sulfide death.SLC3A2,LRPPRC and SLC7A11 can be used as characteristic genes in the regulation of VD by disulfide death,which may affect VD progression through the regulation of disulfide death.
8.Machine learning-based screening of risk factors of early recurrence after surgery for concomitant exotropia and establishment of a Nomogram predic-tion model
Jing XIE ; Li PU ; Zhengjing WANG ; Hongfang HU ; Liang FENG ; Su ZHAO
Recent Advances in Ophthalmology 2025;45(2):115-119
Objective To analyze the risk factors associated with early recurrence after surgery for concomitant exo-tropia and establish a Nomogram prediction model.Methods A retrospective analysis was conducted on 243 cases(486 eyes)of concomitant exotropia treated in the Ophthalmology Department of our hospital from October 2015 to October 2021.The patients were divided into a training set(n=170)and a validation set(n=73)at a ratio of 7∶3.The Lasso re-gression,Boruta algorithm,and random forest algorithm were used to screen risk variables related to postoperative recur-rence of concomitant exotropia.The Spearman correlation analysis and variance inflation factor(VIF)were used to assess collinearity among variables,and a Nomogram prediction model was established using multivariate Cox regression.The re-ceiver operating characteristic curve,calibration curve,and clinical decision curve of the model at 6 months,18 months,and 24 months after surgery were used to assess the efficacy of the model.Results Three machine learning methods in-cluding Lasso regression,Boruta algorithm,and random forest algorithm identified six significant variables that might con-tribute to early recurrence after strabismus surgery from 22 risk variables in both training and validation sets.No collineari-ty was found among the six variables(r<0.6,VIF<5).Multivariate Cox regression revealed that strabismus type(inter-mittent exotropia),preoperative strabismus angle,best-corrected visual acuity(BCVA)in the right eye,BCVA in both eyes,and surgical procedures(unilateral lateral rectus recession)were risk factors for early recurrence after surgery for concomitant exotropia.Meanwhile,a Nomogram prediction model was constructed based on these 6 factors.The receiver operating characteristic,calibration,and clinical decision curves indicated that the prediction model had good accuracy,consistency,and clinical applicability.Conclusion Nomogram prediction model can effectively predict the risk of early recurrence after surgery for concomitant exotropia,and provides a reference for ophthalmologists to intervene early in pa-tients.
9.Dosimetry effect of fluence smoothing in Monaco Treatment Planning System for short-course volumetric modulated arc therapy of preoperative rectal cancer
Yao XIAO ; De-li ZHOU ; Kun-pu SU ; Lin-shan LI ; Meng-yuan SI ; Yan-hai LIU ; Chuan CHEN
Chinese Medical Equipment Journal 2025;46(5):48-53
Objective To investigate the dosimetric differences in preoperative short-course volumetric modulated arc therapy(VMAT)for rectal cancer using different fluence smoothing(FS)levels in the Monaco Treatment Planning System(Monaco TPS).Methods Twenty rectal cancer patients who received preoperative neoadjuvant short-course VMAT at some hospital from September 2021 to December 2022 were retrospectively selected.Four groups of radiotherapy plans were formulated using the Monaco TPS for each case,which were classified into an off group,a low group,a medium group and a high group based on the FS levels.Then the four groups were compared in terms of the dosimetric parameters,monitor unit and number of the segments in the planning target volume(PTV)and organ at risk(OAR).Statistical analysis was performed using SPSS 27.0 software.Results All the four groups had the doses to the target volume meeting clinical requirements,which had no significant differences in the doses to 5%(D5%)and 95%(D95%)to the target volume and the maximum dose(Dmax),minimum dose(Dmin),mean dose(Dmean)and conformity index(all P>0.05).Statistical differences were found between the homogeneity indexes of the four groups(P<0.05),with the medium group behaving the best.The number of the segments rose while the mornitor units decreased siginificantly with the increase of FS levels,with the differences being statistically significant(P<0.05).There were no significant differences between the V25,V20,V15 and V10 of the small intestine,the V25 and V20 of the bladder and the V15 and V10 of the left and right femur(all P>0.05).Conclusion In preoperative short-course VMAT for rectal cancer,clinical requirements can be met with different FS levels in the Monaco TPS,and medium-level FS results in optimal overall dose distribution in terms of treatment planning.[Chinese Medical Equipment Journal,2025,46(5):48-53]
10.Structural and Spatial Analysis of The Recognition Relationship Between Influenza A Virus Neuraminidase Antigenic Epitopes and Antibodies
Zheng ZHU ; Zheng-Shan CHEN ; Guan-Ying ZHANG ; Ting FANG ; Pu FAN ; Lei BI ; Yue CUI ; Ze-Ya LI ; Chun-Yi SU ; Xiang-Yang CHI ; Chang-Ming YU
Progress in Biochemistry and Biophysics 2025;52(4):957-969
ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.

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