1.A multi-center epidemiological study on pneumococcal meningitis in children from 2019 to 2020
Cai-Yun WANG ; Hong-Mei XU ; Gang LIU ; Jing LIU ; Hui YU ; Bi-Quan CHEN ; Guo ZHENG ; Min SHU ; Li-Jun DU ; Zhi-Wei XU ; Li-Su HUANG ; Hai-Bo LI ; Dong WANG ; Song-Ting BAI ; Qing-Wen SHAN ; Chun-Hui ZHU ; Jian-Mei TIAN ; Jian-Hua HAO ; Ai-Wei LIN ; Dao-Jiong LIN ; Jin-Zhun WU ; Xin-Hua ZHANG ; Qing CAO ; Zhong-Bin TAO ; Yuan CHEN ; Guo-Long ZHU ; Ping XUE ; Zheng-Zhen TANG ; Xue-Wen SU ; Zheng-Hai QU ; Shi-Yong ZHAO ; Lin PANG ; Hui-Ling DENG ; Sai-Nan SHU ; Ying-Hu CHEN
Chinese Journal of Contemporary Pediatrics 2024;26(2):131-138
Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]
2.Machine learning algorithms for identifying autism spectrum disorder through eye-tracking in different intention videos
Rong CHENG ; Zhong ZHAO ; Wen-Wen HOU ; Gang ZHOU ; Hao-Tian LIAO ; Xue ZHANG ; Jing LI
Chinese Journal of Contemporary Pediatrics 2024;26(2):151-157
Objective To investigate the differences in visual perception between children with autism spectrum disorder(ASD)and typically developing(TD)children when watching different intention videos,and to explore the feasibility of machine learning algorithms in objectively distinguishing between ASD children and TD children.Methods A total of 58 children with ASD and 50 TD children were enrolled and were asked to watch the videos containing joint intention and non-joint intention,and the gaze duration and frequency in different areas of interest were used as original indicators to construct classifier-based models.The models were evaluated in terms of the indicators such as accuracy,sensitivity,and specificity.Results When using eight common classifiers,including support vector machine,linear discriminant analysis,decision tree,random forest,and K-nearest neighbors(with K values of 1,3,5,and 7),based on the original feature indicators,the highest classification accuracy achieved was 81.90% .A feature reconstruction approach with a decision tree classifier was used to further improve the accuracy of classification,and then the model showed the accuracy of 91.43% ,the specificity of 89.80% ,and the sensitivity of 92.86% ,with an area under the receiver operating characteristic curve of 0.909(P<0.001).Conclusions The machine learning model based on eye-tracking data can accurately distinguish ASD children from TD children,which provides a scientific basis for developing rapid and objective ASD screening tools.[Chinese Journal of Contemporary Pediatrics,2024,26(2):151-157]
3.Risk factors for bronchopulmonary dysplasia in twin preterm infants:a multicenter study
Yu-Wei FAN ; Yi-Jia ZHANG ; He-Mei WEN ; Hong YAN ; Wei SHEN ; Yue-Qin DING ; Yun-Feng LONG ; Zhi-Gang ZHANG ; Gui-Fang LI ; Hong JIANG ; Hong-Ping RAO ; Jian-Wu QIU ; Xian WEI ; Ya-Yu ZHANG ; Ji-Bin ZENG ; Chang-Liang ZHAO ; Wei-Peng XU ; Fan WANG ; Li YUAN ; Xiu-Fang YANG ; Wei LI ; Ni-Yang LIN ; Qian CHEN ; Chang-Shun XIA ; Xin-Qi ZHONG ; Qi-Liang CUI
Chinese Journal of Contemporary Pediatrics 2024;26(6):611-618
Objective To investigate the risk factors for bronchopulmonary dysplasia(BPD)in twin preterm infants with a gestational age of<34 weeks,and to provide a basis for early identification of BPD in twin preterm infants in clinical practice.Methods A retrospective analysis was performed for the twin preterm infants with a gestational age of<34 weeks who were admitted to 22 hospitals nationwide from January 2018 to December 2020.According to their conditions,they were divided into group A(both twins had BPD),group B(only one twin had BPD),and group C(neither twin had BPD).The risk factors for BPD in twin preterm infants were analyzed.Further analysis was conducted on group B to investigate the postnatal risk factors for BPD within twins.Results A total of 904 pairs of twins with a gestational age of<34 weeks were included in this study.The multivariate logistic regression analysis showed that compared with group C,birth weight discordance of>25%between the twins was an independent risk factor for BPD in one of the twins(OR=3.370,95%CI:1.500-7.568,P<0.05),and high gestational age at birth was a protective factor against BPD(P<0.05).The conditional logistic regression analysis of group B showed that small-for-gestational-age(SGA)birth was an independent risk factor for BPD in individual twins(OR=5.017,95%CI:1.040-24.190,P<0.05).Conclusions The development of BPD in twin preterm infants is associated with gestational age,birth weight discordance between the twins,and SGA birth.
4.Finite element analysis of three different minimally invasive fixation methods for distal tibial fractures with soft tissue injury
Mingming WANG ; Zhong ZHANG ; Jianhua SUN ; Gang ZHAO ; Hua SONG ; Huadong YAN ; Bin LYU
Chinese Journal of Tissue Engineering Research 2024;28(6):879-885
BACKGROUND:The treatment of distal tibial fractures with soft tissue injury has always been challenging,and the new retrograde tibial nailing is a new choice.Up to now,there were few reports on the biomechanical properties between the new retrograde tibial nailing,anterograde intramedullary nailing and supercutaneous locking plate. OBJECTIVE:To explore the biomechanical stability of new retrograde tibial nailing,antegrade intramedullary nailing and supercutaneous locking plate in the treatment of distal tibial fractures with soft tissue injury using finite element analysis so as to offer a scientific foundation for clinical application. METHODS:The finite element model of transverse distal tibia fracture was established by relevant software utilizing the CT data of the tibia from a 42-year-old healthy male.Retrograde tibial nailing,antegrade intramedullary nailing and supercutaneous locking plate finite element models were assembled under the principle of fracture fixation.Finally,meshing,applying loads,and data processing were accomplished with the ANSYS 2019 software.Moreover,the stress distribution and displacement of the tibia and internal fixation of each model were compared. RESULTS AND CONCLUSION:(1)The displacement of fracture end in the three groups increased with the increase of load.In all mode loads,the average displacement of the fracture end was the least in the retrograde tibial nailing group,followed by the supercutaneous locking plate group,and the highest in the antegrade intramedullary nailing group.At 800 N vertical load,the displacement difference of the fracture end was statistically significant(P<0.05).There was no statistical significance in other load modes.(2)Under different loads,the tibial stress in the three groups was the highest in the middle of the tibia,and gradually decreased to the proximal and distal ends.The stress distribution of the tibial shaft was the highest in the retrograde tibial nailing group,followed by the supercutaneous locking plate group,and the least in the antegrade intramedullary nailing group.(3)Under different loads,the stress of the tibial stress raiser in the three groups was significantly higher in the supercutaneous locking plate group than in the other two groups,with statistical significance(P<0.05).(4)Under different loads,the stress of the fixators in the three groups was the largest in the supercutaneous locking plate group,followed by the retrograde tibial nailing group,and the minimum in the antegrade intramedullary nailing group.There were significant differences in the stress of fixator stress raiser among the three groups under different loading modes(P<0.05).(5)It is indicated that all three fixation methods have the good anti-rotation ability and axial stability.Retrograde tibial nail shows better biomechanical stability.
5.Biomechanical difference of different fixation methods in bone healing of distal tibial comminuted fractures analyzed by finite element method
Huadong YAN ; Zhong ZHANG ; Gang ZHAO ; Jie LI ; Hua SONG ; Jianhua SUN ; Zhi LIU ; Mingming WANG
Chinese Journal of Tissue Engineering Research 2024;28(24):3814-3821
BACKGROUND:The treatment of distal tibial comminuted fractures with soft tissue injury has always been challenging.The new retrograde tibial nailing and supercutaneous locking plate are important treatment methods,but their strain and stress shielding at the fracture end during different periods of fracture healing and different load conditions have not been reported. OBJECTIVE:To explore the biomechanical stability of retrograde tibial nailing and supercutaneous locking plate in different periods of fracture healing by finite element analysis to offer a scientific foundation for clinical application and rehabilitation exercise. METHODS:The finite element model of distal tibial comminuted fracture was established by utilizing the CT data of the tibia from a 40-year-old healthy male.Retrograde tibial nailing,supercutaneous locking plate,and callus models were assembled in accordance with the principle of fracture fixation.The finite element analysis was performed using ANSYS software to compare the displacement of the fracture end,the stress shielding of the tibia,the stress of the callus,and the stress distribution of the tibia and the fixation device during different periods of fracture healing. RESULTS AND CONCLUSION:(1)The relative displacement of the tibial fracture decreased gradually with the healing of the fracture,and the displacement decreased significantly after 3 months.At 0 and 1 months after operation,the vertical displacement and total displacement of the supercutaneous locking plate group were higher than those in the retrograde intramedullary nail group.The Z-axis displacement(horizontal medial and lateral displacement)of the two fixation methods was more obvious than the X-axis and Y-axis,and the Z-axis displacement of supercutaneous locking plate group was the most obvious.The maximum Z-axis displacement of the two fixation methods was located on the outside of the tibia,and the minimum displacement was located on the inside of the tibia.(2)The stress shielding rate at different periods of fracture healing gradually decreased with time.The stress shielding rate of the retrograde intramedullary nail was higher than that of the supercutaneous locking plate at different stages of fracture healing.After 3 months,the stress shielding rate of the supercutaneous locking plate was reduced to about 4%,and the stress shielding rate of the retrograde intramedullary nail was reduced to about 40%.(3)The stress of the stress concentration site of the callus in the two fixation methods increased with the increase of the load,and the stress of the callus in the supercutaneous locking plate group was always greater than that in the retrograde intramedullary nail group.The maximum stress distribution of the callus was approximately equally distributed among the two modes of fixation,both in the lateral portion of the tibia.(4)As the fracture healed,the maximum stress of the tibia in the two groups decreased gradually,and the stress in the supercutaneous locking plate group was always greater than that in the retrograde intramedullary nail group.The average stress of the maximum stress area of the tibia in the supercutaneous locking plate group under 1 500 N load was 285 MPa,while that in the retrograde intramedullary nail group was 26 MPa.(5)As the fracture healed,the stress of the fixation device in the two groups decreased gradually,and the stress in the supercutaneous locking plate group was significantly higher than that in the retrograde intramedullary nail group.After 3 months,the stress of the two fixation devices decreased significantly.(6)It is indicated that in the early stage of fracture healing,the strain on the fracture end in the retrograde intramedullary nail group is small,and the maximum stress of the tibia is moderate,allowing early loaded.The fractured ends in the supercutaneous locking plate group had too large strain and too large maximum stress of the tibia,which needed to be partially loaded under protection and could not be fully loaded.In the middle and late stages of fracture healing,the tibial retrograde intramedullary nail and the supercutaneous locking plate could be completely loaded,and the stress shielding rate of the supercutaneous locking plate was significantly lower than the tibial retrograde intramedullary nail.
6.IgA nephropathy with mesangial type Ⅲ collagen deposition:2 cases report
Jie-Bo HUANG ; Xiao-Fan CAI ; Zhong-Hua ZHAO ; Zhi-Gang ZHANG ; Qiang SHEN ; Hao WANG ; Hui-Juan WU
Fudan University Journal of Medical Sciences 2024;51(3):426-430
As interstitial collagen,type Ⅲ collagen(Col Ⅲ)does not express in normal glomeruli.However,in Col Ⅲ nephropathy,a large amount of Col Ⅲ deposit in the mesangial and subendothelial area of the glomeruli.IgA nephropathy with Col Ⅲ deposition was extremely rare.In this article,we reported two cases of such disease.After treating with immunosuppressive agents or traditional Chinese medicine decoction,the renal function of the two patients remained stable and the urinary protein levels reduced significantly.
7.Reconstruction of Allen's type IV fingertip amputation via bilateral unequal-sized hallux osteo-onychocutaneous free flaps: A retrospective study with 5-year follow-up
Xiu-Zhong LI ; Xiu-Yun WANG ; Yi-Min ZHOU ; Da-Zhi YU ; Hua-Gang ZHANG ; Shu-Jian HOU ; Ke-Cheng LAO ; Xiao FAN
Chinese Journal of Traumatology 2024;27(6):403-409
Purpose::The reconstruction of Allen's type IV fingertip amputation is a clinical challenge. Our team designed bilateral unequal-sized hallux osteo-onychocutaneous free flaps for the long-term reconstruction of Allen's type IV fingertip amputation and conducted a retrospective study with a 5-year follow-up aims to evaluate the effects of this technique.Methods::A retrospective analysis with a 5-year follow-up including 13 patients with Allen's type IV fingertip amputation who were admitted to our hospital from January 2010 to January 2017 was conducted. The patients were treated with bilateral unequal-sized hallux osteo-onychocutaneous free flaps. The operation time, intraoperative blood loss, and complications were recorded, and the survival rate of the transplanted flaps was calculated. During the 5-year follow-up after operation, the nail growth time was recorded and the finger appearance was observed. At the last follow-up appointment, the length, width, and girth of the reconstructed fingertip and contralateral normal fingertip, range of motion of the reconstructed fingertip and contralateral normal fingertip, Semmes-Weinstein test (for the evaluation of tactile sensation), and two-point discrimination testing results were recorded. SPSS 22.0 software was used for the statistical analysis and the data are presented as mean ± SD.Results::The mean operation time was (5.62 ± 0.51) h, the mean intraoperative blood loss was (34.15 ± 3.13) mL, and the survival rate of the transplanted flaps was 100%. During the 5-year follow-up, the average nail growth time was (10.14 ± 1.98) months and the average bone union time was (3.78 ± 0.91) months. The length, width, and girth of the reconstructed fingertip were (31.52 ± 3.73) mm, (17.82 ± 1.74) mm, and (59.75 ± 3.04) mm, respectively, which did not differ from those of the contralateral normal fingertip. The range of motion of the reconstructed fingertip was (12.15 ± 2.79) degrees which is different from that of the contralateral normal fingertip. The average tactile sensation evaluated via the Semmes-Weinstein test and the average two-point discrimination test of the reconstructed fingertip were (0.39 ± 0.17) g and (7.46 ± 1.14) mm, respectively, which were not different from those of the contralateral normal fingertip. The average Maryland score of feet in the donor area was 87.66 ± 7.39, which was satisfactory.Conclusion::Bilateral unequal-sized hallux osteo-onychocutaneous free flaps are an effective method to reconstruct Allen's type IV fingertip amputations with a satisfactory appearance and good sensory function.
8.The efficacy of radiotherapy based combined therapy for unresectable locally invasive bladder cancer and its associated factors analysis.
Si Jin ZHONG ; Jun Jun GAO ; Ping TANG ; Yue Ping LIU ; Shu Lian WANG ; Hui FANG ; Jing Ping QIU ; Yong Wen SONG ; Bo CHEN ; Shu Nan QI ; Yuan TANG ; Ning Ning LU ; Hao JING ; Yi Rui ZHAI ; Ai Ping ZHOU ; Xin Gang BI ; Jian Hui MA ; Chang Ling LI ; Yong ZHANG ; Jian Zhong SHOU ; Nian Zeng XING ; Ye Xiong LI
Chinese Journal of Oncology 2023;45(2):175-181
Objective: Retrospective analysis of the efficacy and influencing factors of bladder preservation integrated therapy for unresectable invasive bladder cancer confined to the pelvis was done, also including the bladder function preservation and adverse effects analysis. Methods: Sixty-nine patients with unresectable locally invasive bladder cancer who received radiotherapy-based combination therapy from March 1999 to December 2021 at our hospital were selected. Among them, 42 patients received concurrent chemoradiotherapy, 32 underwent neoadjuvant chemotherapyand 43 with transurethral resection of bladder tumors (TURBT) prior to radiotherapy. The late adverse effect of radiotherapy, preservation of bladder function, replase and metastasis and survival were followed-up. Cox proportional hazards models were applied for the multifactorial analysis. Results: The median age was 69 years. There were 63 cases (91.3%) of uroepithelial carcinoma, 64 of stage Ⅲ and 4 of stage Ⅳ. The median duration of follow-up was 76 months. There were 7 grade 2 late genito urinary toxicities, 2 grade 2 gastrointestinal toxicities, no grade 3 or higher adverse events occurred. All patients maintained normal bladder function, except for 8 cases who lost bladder function due to uncontrolled tumor in the bladder. Seventeen cases recurred locally. There were 11 cases in the concurrent chemoradiotherapy group with a local recurrence rate of 26.2% (11/42) and 6 cases in the non-concurrent chemoradiotherapy group with a local recurrence rate of 22.2% (6/27), and the difference in local recurrence rate between the two groups was not statistically significant (P=0.709). There were 23 cases of distant metastasis (including 2 cases of local recurrence with distant metastasis), including 10 cases in the concurrent chemoradiotherapy group with a distant metastasis rate of 23.8% (10/42) and 13 cases in the non-concurrent chemoradiotherapy group with a distant metastasis rate of 48.1% (13/27), and the distant metastasis rate in the non-concurrent chemoradiotherapy group was higher than that in the concurrent chemoradiotherapy group (P=0.036). The median 5-year overall survival (OS) time was 59 months and the OS rate was 47.8%. The 5-year progression-free survival (PFS) time was 20 months and the PFS rate was 34.4%. The 5-year OS rates of concurrent and non-concurrent chemoradiotherapy group were 62.9% and 27.6% (P<0.001), and 5-year PFS rates were 45.4% and 20.0%, respectively (P=0.022). The 5-year OS rates of with or without neoadjuvant chemotherapy were 78.4% and 30.1% (P=0.002), and the 5-year PFS rates were 49.1% and 25.1% (P=0.087), respectively. The 5-year OS rates with or without TURBT before radiotherapy were 45.5% and 51.9% (P=0.233) and the 5-year PFS rates were 30.8% and 39.9% (P=0.198), respectively. Multivariate Cox regression analysis results showed that the clinical stage (HR=0.422, 95% CI: 0.205-0.869) was independent prognostic factor for PFS of invasive bladder cancer. The multivariate analysis showed that clinical stages (HR=0.278, 95% CI: 0.114-0.678), concurrent chemoradiotherapy (HR=0.391, 95% CI: 0.165-0.930), neoadjuvant chemotherapy (HR=0.188, 95% CI: 0.058-0.611), and recurrences (HR=10.855, 95% CI: 3.655-32.638) were independent prognostic factors for OS of invasive bladder cancer. Conclusion: Unresectable localized invasive bladder cancer can achieve satisfactory long-term outcomes with bladder-preserving combination therapy based on radiotherapy, most patients can retain normal bladder function with acceptable late adverse effects and improved survival particularly evident in patients with early, concurrent chemoradiotherapy and neoadjuvant chemotherapy.
Humans
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Aged
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Treatment Outcome
;
Retrospective Studies
;
Combined Modality Therapy
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Chemoradiotherapy/methods*
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Urinary Bladder Neoplasms/radiotherapy*
;
Antineoplastic Combined Chemotherapy Protocols/therapeutic use*
;
Neoplasm Staging
9.Pathological features and clinicopathological significance of TERT promoter mutation in breast fibroepithelial tumors without definite diagnosis.
Ji Gang WANG ; Yan Jiao HU ; Jing Jing GUAN ; Hong Yun LIU ; Zhong Jun BI ; Long Xiao ZHANG ; Yi Xuan LIU ; Xiao Ming XING
Chinese Journal of Pathology 2023;52(2):153-159
Objective: To investigate the pathological features and the clinicopathological significance of TERT detection in those tumors that were difficult to diagnosis. Methods: A total of 93 cases of fibroepithelial tumors without definite diagnosis were collected from the Affiliated Hospital of Qigndao University between 2013 and 2021. The clinical details such as patients' age and tumor size were collected. All slides were re-reviewed and the pathologic parameters, including stromal cellularity, stromal cell atypia, stromal cell mitoses, and stromal overgrowth were re-interpreted. Sanger sequencing was used to detect TERT promoter status, and immunohistochemistry was performed to detect TERT protein expression. The relationship between TERT promoter mutation as well as protein expression levels and the clinicopathological parameters were also analyzed. Results: The patients' ages ranged from 30 to 71 years (mean of 46 years); the tumor size ranged from 1.2 to 8.0 cm (mean 3.8 cm). These tumors showed the following morphologic features: leafy structures in the background of fibroadenoma, or moderately to severely abundant stromal cells. The interpretations of tumor border status were ambiguous in some cases. The incidence of TERT promoter mutation was high in patients of age≥50 years, tumor size≥4 cm, and stromal overgrowth at ×4 or ×10 objective, and these clinicopathologic features were in favor of diagnosis of phyllodes tumors. TERT protein expression levels was not associated with the above clinicopathologic parameters and its promoter mutation status. Conclusions: The diagnostic difficulty for the breast fibroepithelial tumors is due to the difficulty in recognition of the leafy structures or in those cases with abundant stromal cells. A comprehensive evaluation combined with morphologic characteristics and molecular parameters such as TERT promoter may be helpful for the correct diagnosis and better evaluating recurrence risk.
Humans
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Adult
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Middle Aged
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Aged
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Female
;
Neoplasms, Fibroepithelial/pathology*
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Phyllodes Tumor/genetics*
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Stromal Cells
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Fibroadenoma/pathology*
;
Breast Neoplasms/pathology*
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Mutation
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Telomerase/genetics*
10.Variation and interaction mechanism between active components in Rheum officinale and rhizosphere soil microorganisms under drought stress.
Feng-Pu XIE ; Nan WANG ; Jing GAO ; Gang ZHANG ; Zhong-Xing SONG ; Yuan-Yuan LI ; Ya-Li ZHANG ; Duo-Yi WANG ; Rui LI ; Mi-Mi LIU ; Zhi-Shu TANG
China Journal of Chinese Materia Medica 2023;48(6):1498-1509
To explore the changes and the reaction mechanisms between soil microecological environment and the content of secon-dary metabolites of plants under water deficit, this study carried out a pot experiment on the 3-leaf stage seedlings of Rheum officinale to analyze their response mechanism under different drought gradients(normal water supply, mild, moderate, and severe drought). The results indicated that the content of flavonoids, phenols, terpenoids, and alkaloids in the root of R. officinale varied greatly under drought stresses. Under mild drought stress, the content of substances mentioned above was comparatively high, and the content of rutin, emodin, gallic acid, and(+)-catechin hydrate in the root significantly increased. The content of rutin, emodin, and gallic acid under severe drought stress was significantly lower than that under normal water supply. The number of species, Shannon diversity index, richness index, and Simpson index of bacteria in the rhizosphere soil were significantly higher than those in blank soil, and the number of microbial species and richness index decreased significantly with the aggravation of drought stresses. In the context of water deficit, Cyanophyta, Firmicutes, Actinobacteria, Chloroflexi, Gemmatimonadetes, Streptomyces, and Actinomyces were the dominant bacteria in the rhizosphere of R. officinale. The relative content of rutin and emodin in the root of R. officinale was positively correlated with the relative abundance of Cyanophyta and Firmicutes, and the relative content of(+)-catechin hydrate and(-)-epicatechin gallate was positively correlated with the relative abundance of Bacteroidetes and Firmicutes. In conclusion, appropriate drought stress can increase the content of secondary metabolites of R. officinale from physiological induction and the increase in the association with beneficial microbe.
Rhizosphere
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Rheum
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Droughts
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Soil
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Catechin
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Emodin
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Bacteria/metabolism*
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Water/metabolism*
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Firmicutes
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Soil Microbiology

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