1.Global burden of non-communicable diseases attributable to kidney dysfunction with projection into 2040.
Jing CHEN ; Chunyang LI ; Ci Li Nong BU ; Yujiao WANG ; Mei QI ; Ping FU ; Xiaoxi ZENG
Chinese Medical Journal 2025;138(11):1334-1344
BACKGROUND:
Spatiotemporal disparities exist in the disease burden of non-communicable diseases (NCDs) attributable to kidney dysfunction, which has been poorly assessed. The present study aimed to evaluate the spatiotemporal trends of the global burden of NCDs attributable to kidney dysfunction and to predict future trends.
METHODS:
Data on NCDs attributable to kidney dysfunction, quantified using deaths and disability-adjusted life-years (DALYs), were extracted from the Global Burden of Diseases Injuries, and Risk Factors (GBD) Study in 2019. Estimated annual percentage change (EAPC) of age-standardized rate (ASR) was calculated with linear regression to assess the changing trend. Pearson's correlation analysis was used to determine the association between ASR and sociodemographic index (SDI) for 21 GBD regions. A Bayesian age-period-cohort (BAPC) model was used to predict future trends up to 2040.
RESULTS:
Between 1990 and 2019, the absolute number of deaths and DALYs from NCDs attributable to kidney dysfunction increased globally. The death cases increased from 1,571,720 (95% uncertainty interval [UI]: 1,344,420-1,805,598) in 1990 to 3,161,552 (95% UI: 2,723,363-3,623,814) in 2019 for both sexes combined. Both the ASR of death and DALYs increased in Andean Latin America, the Caribbean, Central Latin America, Southeast Asia, Oceania, and Southern Sub-Saharan Africa. In contrast, the age-standardized metrics decreased in the high-income Asia Pacific region. The relationship between SDI and ASR of death and DALYs was negatively correlated. The BAPC model indicated that there would be approximately 5,806,780 death cases and 119,013,659 DALY cases in 2040 that could be attributed to kidney dysfunction. Age-standardized death of cardiovascular diseases (CVDs) and CKD attributable to kidney dysfunction were predicted to decrease and increase from 2020 to 2040, respectively.
CONCLUSION
NCDs attributable to kidney dysfunction remain a major public health concern worldwide. Efforts are required to attenuate the death and disability burden, particularly in low and low-to-middle SDI regions.
Humans
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Noncommunicable Diseases/epidemiology*
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Global Burden of Disease
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Disability-Adjusted Life Years
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Male
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Female
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Risk Factors
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Middle Aged
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Kidney Diseases/epidemiology*
;
Bayes Theorem
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Adult
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Aged
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Global Health
;
Quality-Adjusted Life Years
2.Effect and mechanism of alkaloids from Portulacae Herba on ulcerative colitis in mice based on TLR4/MyD88/NF-κB signaling pathway.
Jia-Hui ZHENG ; Ying-Ying SONG ; Tian-Ci ZHANG ; Wen-Ting WANG ; Zhi-Ping YANG ; Jin-Xia AI
China Journal of Chinese Materia Medica 2025;50(4):874-881
This study investigated the functions and regulatory mechanism of Portulacae Herba and its chemical components on the Toll-like receptor 4(TLR4)/myeloid differentiation primary response 88(MyD88)/nuclear factor kappa B(NF-κB) inflammatory signaling pathway in the colon tissue of mice with dextran sodium sulfate(DSS)-induced ulcerative colitis(UC). A total of 35 mice were randomly divided into groups, including a blank group, a model group, a mesalazine group(0. 5 g·kg~(-1)), and low, medium,and high dose alkaloids from Portulacae Herba groups(9, 18, 36 mg·kg~(-1)), and a combination treatment group, with 5 mice in each group. The blank group was given purified water, while the other groups were continuously given a 3% DSS solution for 7 days to induce the UC model. From day 8 onwards, the treatment group received oral gavage according to the prescribed doses for 14 days. The overall condition, body weight, stool characteristics, and presence of blood in the stool were recorded daily. After the experiment, the disease activity index(DAI) was assessed for each group, and colon length was measured. Histopathological changes in colon tissue were examined using hematoxylin-eosin(HE) staining. The levels of pro-inflammatory cytokines, tumor necrosis factor-α(TNF-α),and interleukin-1β( IL-1β) in serum were measured by enzyme-linked immunosorbent assay( ELISA). The protein and m RNA expression of TLR4, MyD88, and NF-κB in colon tissue were measured using Western blot and quantitative real-time PCR(qPCR).Compared to the blank group, the model group showed a significant decrease in body weight, a notable increase in DAI scores, a significant shortening of colon length, and evident histopathological damage. The levels of inflammatory cytokines TNF-α and IL-1β in the serum were significantly elevated, and the protein and m RNA expression of TLR4, MyD88, and NF-κB in colon tissue were significantly up-regulated. In contrast, the alkaloids from Portulacae Herba treatment groups significantly improved symptoms and reduced body weight loss in mice, decreased DAI scores, alleviated colon shortening, lowered serum levels of TNF-α and IL-1β,significantly down-regulated the expression levels of TLR4, MyD88, and NF-κB proteins and genes in colon tissue, as well as reduced histopathological damage. Therefore, the study suggests that alkaloids from Portulacae Herba can alleviate intestinal inflammation damage in DSS-induced UC mice, with its mechanism involving the TLR4/MyD88/NF-κB signaling pathway.
Animals
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Colitis, Ulcerative/immunology*
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Toll-Like Receptor 4/immunology*
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Myeloid Differentiation Factor 88/metabolism*
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Mice
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NF-kappa B/metabolism*
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Signal Transduction/drug effects*
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Male
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Alkaloids/administration & dosage*
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Drugs, Chinese Herbal/administration & dosage*
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Humans
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Female
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Colon/metabolism*
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Disease Models, Animal
3.Two new sesquiterpenoids from Wenyujin Rhizoma Concisum.
Yu LI ; Min CHEN ; Cheng ZHU ; Ci-Mei WU ; Chao-Jie WANG ; Jian-Yong DONG
China Journal of Chinese Materia Medica 2025;50(10):2704-2710
This study explored the active ingredients for anti-angiogenesis in Wenyujin Rhizoma Concisum. Ten sesquiterpenoids were isolated from Wenyujin Rhizoma Concisum by silica gel column chromatography, thin layer chromatography, and high performance liquid chromatography. According to the results of multiple spectroscopic methods and circular dichroism, they were identified as wenyujinlactam A(1),(4S,7S)11-hydroxycurdione(2), 8,9-seco-4β-hydroxy-1α,5βH-7(11)-guaen-8,10-olide(3), curcumadione(4), phaeocaulisin E(5), procurcumadiol(6), zedouronediol(7), epiprocurcumenol(8), gajutsulactone A(9), and(7Z)-1β,4α-dihydroxy-5α,8β(H)-eudesm-7(11)-en-8,12-olide(10). Compounds 1 and 2 were new sesquiterpenoids. Compounds 1, 6, 8, and 10 can inhibit human umbilical vein endothelial cells(HUVEC) proliferation with IC_(50) values of 38.83, 45.19, 32.12, and 37.80 μmol·L~(-1), respectively. Compounds 1 and 10 can inhibit HUVEC migration with IC_(50) values of 29.70 and 36.48 μmol·L~(-1), respectively.
Sesquiterpenes/isolation & purification*
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Humans
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Drugs, Chinese Herbal/isolation & purification*
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Rhizome/chemistry*
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Human Umbilical Vein Endothelial Cells/drug effects*
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Molecular Structure
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Cell Proliferation/drug effects*
4.Common detoxification mechanisms in processing of toxic medicinal herbs of the same genus: a case study of Euphorbia pekinensis, E. ebracteolata, and E. fischeriana.
En-Ci JIANG ; Hong-Li YU ; Shu-Rui ZHANG ; Bing-Bing LIU ; Xin-Zhi WANG ; Hao WU
China Journal of Chinese Materia Medica 2025;50(13):3615-3675
Traditional Chinese medicine(TCM) processing is a specialized pharmaceutical technique with the primary objective of reducing the toxicity of medicinal substances. Euphorbia pekinensis, E. ebracteolata, and E. fischeriana, all belonging to Euphorbiaceae, are classified as drastic purgative herbs, traditionally used for eliminating retained water, reducing swelling, resolving toxicity, and dispersing masses. However, these herbs are also associated with adverse effects such as abdominal pain and diarrhea. Accordingly, they are commonly processed with vinegar, milk, or Terminalia chebula decoction to reduce the toxicity. This review summarizes the chemical constituents, pharmacological activities, historical evolution of processing methods, and detoxification mechanisms of the three toxic Euphorbia species. The primary toxic constituents are terpenoids. Specifically, E. ebracteolata and E. fischeriana are rich in diterpenoids, while E. pekinensis contains diterpenoids, triterpenoids, and sesquiterpenoids. Studies have shown that vinegar processing promotes structural transformations of diterpenoids, including ether bond hydrolysis, lactone ring opening, esterification, oxidation, and epoxide ring cleavage, thereby reducing the content and toxicity of these compounds. Milk processing facilitates the dissolution of toxic components into the residual liquid of excipients, leading to decreases in their concentrations in the final decoction pieces. Processing with T. chebula decoction raises the levels of tannin-derived phenolic acids, which antagonize the adverse effects of the intestine. These findings reveal a shared detoxification pattern among the three toxic herbs. Accordingly, this review proposes the concept of a shared detoxification mechanism for toxic herbs belonging to the same family or genus. That is, toxic herbs belonging to the same taxon often exhibit similar toxicological profiles and can undergo detoxification through the same processing methods, reflecting common underlying mechanisms. Investigating such shared mechanisms across multiple species of the same genus offers a promising research strategy. Ultimately, the research into processing-induced detoxification mechanisms provides both theoretical and practical support for ensuring the safety of toxic TCM.
Euphorbia/classification*
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Drugs, Chinese Herbal/metabolism*
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Humans
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Animals
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Inactivation, Metabolic
;
Medicine, Chinese Traditional
5.Three-dimensional kinematic analysis can improve the efficacy of acupoint selection for post-stroke patients with upper limb spastic paresis: A randomized controlled trial.
Xin-Yun HUANG ; Ou-Ping LIAO ; Shu-Yun JIANG ; Ji-Ming TAO ; Yang LI ; Xiao-Ying LU ; Yi-Ying LI ; Ci WANG ; Jing LI ; Xiao-Peng MA
Journal of Integrative Medicine 2025;23(1):15-24
BACKGROUND:
China is seeing a growing demand for rehabilitation treatments for post-stroke upper limb spastic paresis (PSSP-UL). Although acupuncture is known to be effective for PSSP-UL, there is room to enhance its efficacy.
OBJECTIVE:
This study explored a semi-personalized acupuncture approach for PSSP-UL that used three-dimensional kinematic analysis (3DKA) results to select additional acupoints, and investigated the feasibility, efficacy and safety of this approach.
DESIGN, SETTING, PARTICIPANTS AND INTERVENTIONS:
This single-blind, single-center, randomized, controlled trial involved 74 participants who experienced a first-ever ischemic or hemorrhagic stroke with spastic upper limb paresis. The participants were then randomly assigned to the intervention group or the control group in a 1:1 ratio. Both groups received conventional treatments and acupuncture treatment 5 days a week for 4 weeks. The main acupoints in both groups were the same, while participants in the intervention group received additional acupoints selected on the basis of 3DKA results. Follow-up assessments were conducted for 8 weeks after the treatment.
MAIN OUTCOME MEASURES:
The primary outcome was the Fugl-Meyer Assessment for Upper Extremity (FMA-UE) response rate (≥ 6-point change) at week 4. Secondary outcomes included changes in motor function (FMA-UE), Brunnstrom recovery stage (BRS), manual muscle test (MMT), spasticity (Modified Ashworth Scale, MAS), and activities of daily life (Modified Barthel Index, MBI) at week 4 and week 12.
RESULTS:
Sixty-four participants completed the trial and underwent analyses. Compared with control group, the intervention group exhibited a significantly higher FMA-UE response rate at week 4 (χ2 = 5.479, P = 0.019) and greater improvements in FMA-UE at both week 4 and week 12 (both P < 0.001). The intervention group also showed bigger improvements from baseline in the MMT grades for shoulder adduction and elbow flexion at weeks 4 and 12 as well as thumb adduction at week 4 (P = 0.007, P = 0.049, P = 0.019, P = 0.008, P = 0.029, respectively). The intervention group showed a better change in the MBI at both week 4 and week 12 (P = 0.004 and P = 0.010, respectively). Although the intervention group had a higher BRS for the hand at week 12 (P = 0.041), no intergroup differences were observed at week 4 (all P > 0.05). The two groups showed no differences in MAS grades as well as in BRS for the arm at weeks 4 and 12 (all P > 0.05).
CONCLUSION:
Semi-personalized acupuncture prescription based on 3DKA results significantly improved motor function, muscle strength, and activities of daily living in patients with PSSP-UL.
TRIAL REGISTRATION
Chinese Clinical Trial Registry ChiCTR2200056216. Please cite this article as: Huang XY, Liao OP, Jiang SY, Tao JM, Li Y, Lu XY, Li YY, Wang C, Li J, Ma XP. Three-dimensional kinematic analysis can improve the efficacy of acupoint selection for post-stroke patients with upper limb spastic paresis: A randomized controlled trial. J Integr Med. 2025; 23(1): 15-24.
Humans
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Male
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Female
;
Middle Aged
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Acupuncture Points
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Upper Extremity/physiopathology*
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Biomechanical Phenomena
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Single-Blind Method
;
Aged
;
Stroke/therapy*
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Acupuncture Therapy/methods*
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Stroke Rehabilitation/methods*
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Adult
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Muscle Spasticity/therapy*
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Paresis/physiopathology*
;
Treatment Outcome
6.Analysis of factors influencing elevated blood pressure and overweight/obesity and their comorbidities among Tibetan middle school students in Lhasa City
Chinese Journal of School Health 2024;45(3):423-426
Objective:
To explore the prevalence of elevated blood pressure and overweight/obesity and their comorbidities among Tibetan middle school students in Lhasa, and to analyze their association with lifestyle and other factors, so as to provide a basis for the intervention measures targeting elevated blood pressure, overweight and obesity among middle school students in high altitude area.
Methods:
Using a stratified cluster random sampling method in September 2021, a total of 1 488 Tibetan junior and high students from Lhasa City were investigated with blood pressure measurement, physical examination and questionnaire survey. The influencing factors of elevated blood pressure, overweight and obesity and their comorbidities association were analyzed by multivariate Logistic regression.
Results:
The prevalence of elevated blood pressure, overweight/obesity and their comorbidities were 17.8%, 17.4% , 5.0% respectively. Multivariate Logistic regression analysis showed that age( OR =0.81), residence, body mass inex(BMI) and gender were the influencing factors of elevated blood pressure; and the risks of elevated blood pressure in female students were higher than male students ( OR =1.89), suburban students were higher than urban students ( OR =8.06), overweight and obesity groups were higher than normal groups ( OR =2.55, 2.87) ( P <0.05). Adjusting for confounding factors such as gender, residence and school, and BMI (only for elevated blood pressure), daily screen time ≥2 h was positively correlated with elevated blood pressure, overweight/obesity and its comorbidities ( OR =1.56, 1.59 , 2.51) ( P <0.05).
Conclusions
The prevalence of elevated blood pressure, overweight/obesity are relatively high in Lhasa. Longer screen time is a common factor affecting with elevated blood pressure, overweight/obesity and comorbidities among Tibetan students. Measures should be taken intervene in the lifestyle of Tibetan students, in order to reduce elevated blood pressure and overweight/obesity.
7.The Effect of Yangyin Xifeng Tongluo Formula (养阴熄风通络方) and Its Core Herb-Pairs on Prevention of Aconitine-Induced Ventricular Precontraction in Rats
Yawen CAO ; Ci WANG ; Lin WANG ; Shuai WANG ; Xianliang WANG ; Jingyuan MAO
Journal of Traditional Chinese Medicine 2024;65(11):1174-1179
ObjectiveTo observe the effect of Yangyin Xifeng Tongluo Formula (养阴熄风通络方) and its core herbs combination on prevention of ventricular precontraction (PVC). MethodsExperiment 1: Forty SD rats were randomly divided into model group, formula group, core herb-pairs medium-dose group and amiodarone group, with 10 rats in each group. Rats in the model group were given 10 ml/(kg·d) of pure water by gavage, rats in the formula group were given 1.125 g/(kg·d) of Yangyin Xifeng Tongluo Granules (养阴熄风通络方颗粒) by gavage, rats in the core herb-pairs medium-dose group were given 0.585 g/(kg·d) of granules of core herb-pairs by gavage, and rats in the amiodarone group were given 18 mg/(kg·d) of amiodarone hydrochloride tablets by gavage. The rats in each group were gavaged once a day for 14 consecutive days, and then a PVC model was established using rat tail vein injection of aconitine 25 μg/kg to compare the mortality and incidence of PVC, ventricular tachycardia (VT) and ventricular fibrillation (VF), the time of the appearance of PVC, and the duration of PVC in the rats in each group. Experiment 2: Sixty SD rats were randomly divided into model group, the amiodarone group, and the core herb-pairs of low, medium and high dose groups, 12 rats in each group. Rats in the model group were gavaged with 10 ml/(kg·d) of purified water, rats in the low, medium, and high dose groups were gavaged with 0.2925, 0.585, and 1.17 g/(kg·d) of the core herb-pairs granules respectively, and rats in the amiodarone group were gavaged with 18 mg/(kg·d) of amiodarone hydrochloride tablets. All of them were gavaged once a day. After 14 days, rats in each group were injected intravenously into the tail vein with aconitine 25 μg/kg, and then the rats in each group were observed to show the mortality and incidence of PVC, VT and VF, and the time of appearance and duration of PVC. ResultsExperiment 1: Compared with the model group, The difference in the incidence of PVC in rats of all groups was not statistically signi-ficant (P>0.05), and the mortality and incidence of VT and VF in rats in the formula group, the core herb-pairs medium-dose group, and the amiodarone group significantly reduced, with delayed time of the occurrence of PVC and shorter duration of the PVC (P<0.05 or P<0.01) as compared with the model group, whereas the difference between each group with medication intervention was not statistically significant (P>0.05). Experiment 2: There was no statistically significant difference in the incidence of PVC in all groups (P>0.05), and the mortality and incidence of VT and VF reduced in the core herb-pairs of low-, medium-, and high-dose groups and in the amiodarone group, and the appearance of PVC delayed and its duration shortened (P<0.05 or P<0.01) as compared with the control group, whereas the differences were not statistically significant in the comparison among groups with medication (P>0.05). ConclusionBoth Yangyin Xifeng Tongluo Formula and its core herb-pairs could delay the time of occurrence and shorten the duration of PVC.
8.Summary of the best evidence for early exercise rehabilitation in patients with mechanically ventilated ICU-acquired weakness
Ruixiang SUN ; Haijiao JIANG ; Jun WANG ; Jintian YU ; Quan ZHOU ; Ke FANG ; Caizhe CI
Chinese Critical Care Medicine 2024;36(7):745-752
Objective:To integrate the best evidence for early rehabilitation of mechanically ventilated ICU-acquired weakness (ICU-AW) patients using evidence-based methods, providing evidence-based basis for standardized evaluation and intervention of early exercise therapy for mechanically ventilated ICU-AW patients.Methods:A systematic search was conducted on the American Thoracic Society (ATS) Clinical Practice Guidelines, Registered Nurses' Association of Ontario (RNAO), Guidelines International Network (GIN), Canadian Medical Association Clinical Practice Guideline Library (CMACPGL), BMJ Clinical Evidence, UpToDate, Scottish Intercollegiate Guidelines Network (SIGN), PubMed, Cochrane Library, National Guideline Clearinghouse (NGC), Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL), UM-library, Physiotherapy Evidence Database (PEDro), National Institute for Health and Care Excellence (NICE), New Zealand Guidelines Group (NZGG), Chinese Medical Pulse Guidelines Website, CNKI and Wanfang data and other Chinese and English databases, professional team websites, and guideline websites for expert consensus, guidelines, randomized collected trial (RCT), systematic reviews and other evidence on early exercise rehabilitation for mechanically ventilated ICU-AW patients. The search time limit was from the establishment of the database to December 31, 2023. Literature search, screening, evaluation, information extraction was independently conducted by two evaluators with cross checking, and quality evaluation of the included literature was conducted.Results:A total of 21 literatures were enrolled, including 5 guidelines, 5 systematic reviews, 4 expert consensuses, and 7 RCT, all of which with high evidence level and all were enrolled. They were summarized into seven aspects with assessment screening, exercise safety standards, precautions, setting of exercise time, exercise intensity, exercise sequence, and recommended exercise content as the core, and 32 best evidences.Conclusions:The evidence summarized can provide evidence-based basis for standardized assessment and intervention of early exercise rehabilitation in mechanically ventilated ICU-AW patients. ICU medical practitioners need to combine the actual clinical environment, individual differences and rehabilitation goals of patients, to provide targeted health guidance and intervention for the prevention of ICU-AW in mechanically ventilated patients.
9.Determination of Organophosphate Esters and Metabolites in Serum and Urine by Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry
Wen-Qi WU ; Xiao-Xia WANG ; Wen-Bin LIU ; Li-Rong GAO ; Yang YU ; Tian-Qi JIA ; Zhe-Yuan SHI ; Yun-Chen HE ; Jing-Lin DENG ; Chun-Ci CHEN
Chinese Journal of Analytical Chemistry 2024;52(9):1346-1354,中插29-中插35
A new method was developed for simultaneous detection of total 19 kinds of organophosphate esters(OPEs)and their diester metabolites(di-OPEs)in human serum(1.0 mL)and urine(1.5 mL)with low volume of samples.The target compounds were determined using ultra-high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS)after acetonitrile liquid-liquid extraction combined with purification using an ENVI-18 solid-phase extraction(SPE)column.OPEs and di-OPEs were separated using a Shim-pack GIST C18 column(100 mm×2.1 mm,2 μm)with a Shim-pack GIST-HP(G)C18 guard column.An electrospray ionization source(ESI)was employed in mass spectrometry analysis,with positive/negative ion mode using the multiple reaction monitoring(MRM).All target compounds were separated within 15 min,and exhibited good linear relationships in the concentration range of 2-100 ng/mL,with correlation coefficients(R2)above 0.994.The method detection limits(MDL)in serum ranged from 0.001 to 0.178 ng/mL and the MDL in urine ranged from 0.001 to 0.119 ng/mL.The recoveries of the analytes spiked in serum and urine matrices at two concentration levels were 30.5%-126.8%,with the relative standard deviations(RSDs)ranged from 1%to 23%.In addition,paired serum and urine samples from 11 patients were analyzed.For all samples tested,the internal standards of OPEs exhibited recoveries between 61%and 114%,whereas the internal standards for di-OPEs had recoveries ranging from 43%to 103%.OPEs and di-OPEs exhibited high detection frequencies in 22 serum and urine samples.Triethyl phosphate(TEP),tributyl phosphate(TBP),tris(2-ethylhexyl)phosphate(TEHP),tris(2-butoxyethyl)phosphate(TBEP),tris(1-chloro-2-propyl)phosphate(TCIPP),triphenyl phosphate(TPHP),tri-m-tolyl-phosphate(TMTP)and 2-ethylhexyl diphenyl phosphate(EHDPP)were universally detected in all serum samples.TCIPP was identified at the highest concentrations(median 0.548 ng/mL)in serum samples.In urine samples,the detection frequency for 12 kinds of target compounds reached 100%.Notably,TBP emerged as the predominant OPE in urine,demonstrating a median concentration of 0.506 ng/mL.Regarding di-OPEs,bis(2-chloroethyl)phosphate(BCEP)and bis(2-butoxyethyl)hydrogen phosphate(BBOEP)were the most abundant in urine,with median concentrations of 6.404 and 2.136 ng/mL,respectively.The total concentrations of OPEs and di-OPEs in serum and urine were 1.580-3.843 ng/mL and 5.149-17.537 ng/mL,respectively.These results not only confirmed the effectiveness of the method in detection of OPEs and di-OPEs in biological matrices,but also revealed the widespread presence of OPE compounds in human body and pointed to potential exposure risks.
10.Construction and Analysis of Finite Element Models for Oval Root Canals after Preparation with Micro-Crack
Ci CHEN ; Tong WANG ; Huiying LI ; Jing FU ; Jinghan GUO ; Haiping XU
Journal of Medical Biomechanics 2024;39(4):724-729
Objective To analyze the stress distributions of two root canal preparation shapes of oval root canals with micro-crack.Methods Twenty single-canal mandibular premolars with oval canals were expanded to create micro-cracks.Roots were sectioned after staining.The generation and distribution of dentin micro-cracks were observed under microscope.Then a finite element(FE)model of sectioned enlarged oval canal roots with micro-cracks was established.The stress distribution of micro-crack and root were analyzed under lateral loading.Results Cracks always appeared in the buccolingual sides of oval canal roots and extended from the intracanal wall to the root surface.This was consistent with the stress concentration on the buccolingual side of the root canal wall shown by FE analysis.When micro-cracks occurred,stresses were transferred to the crack tip and the peak values increased sharply nearly 5 times.This made the cracks propagate easily along this direction,especially in the long axis direction of the tooth.Conclusions The presence of micro-cracks does not change the general stress concentration on root with two preparation morphologies of oval canals.However,the micro-crack causes an extreme stress concentration in the crack tip.This may be the mechanism of rapid propagation of microcracks into vertical root fracture,and dentists need to pay high attention.


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