1.Detection of Amantadine by Label-free Fluorescence Method Based on Truncated Aptamer and Molybdenum Disulfide Nanosheet Signal Enhancement Strategy
Yi-Feng LAN ; Bo-Ya HOU ; Zhi-Wen WEI ; Wen LIU ; Chao ZHANG ; Ya-Hui ZUO ; Ke-Ming YUN
Chinese Journal of Analytical Chemistry 2024;52(2):208-219,中插4-中插7
Amantadine(AMD)residue can accumulate in organisms through the food chain and cause serious harm to human body.AMD can specifically bind to AMD specific aptamer and cause its conformation to change from a random single strand to a stem-loop structure.To avoid the influence of excess nucleotides on binding of aptamer to AMD,the truncation of the AMD original aptamer J was optimized by retaining an appropriate stem-loop structure,and a new type of truncation aptamers was developed in this work.By comparing the truncated aptamer with the original aptamer,it was found that the truncated aptamer J-7 had better affinity and specificity with AMD.The detection limit of AMD was 0.11 ng/mL by using J-7 as specific recognition element and molybdenum disulfide nanosheet(MoS2Ns)as signal amplification element.The developed method base on truncated aptamer J-7 was used for detection of AMD in milk,yogurt and SD rat serum samples for the first time with recoveries of 86.6%-108.2%.This study provided a reference for truncating other long sequence aptamers and provided a more sensitive detection method for monitoring AMD residues in food.
2.Pretreatment and analysis techniques development of TKIs in biological samples for pharmacokinetic studies and therapeutic drug monitoring
Chen LAN ; Zhang YUAN ; Zhang YI-XIN ; Wang WEI-LAI ; Sun DE-MEI ; Li PENG-YUN ; Feng XUE-SONG ; Tan YUE
Journal of Pharmaceutical Analysis 2024;14(4):439-459
Tyrosine kinase inhibitors(TKIs)have emerged as the first-line small molecule drugs in many cancer therapies,exerting their effects by impeding aberrant cell growth and proliferation through the mod-ulation of tyrosine kinase-mediated signaling pathways.However,there exists a substantial inter-individual variability in the concentrations of certain TKIs and their metabolites,which may render patients with compromised immune function susceptible to diverse infections despite receiving theo-retically efficacious anticancer treatments,alongside other potential side effects or adverse reactions.Therefore,an urgent need exists for an up-to-date review concerning the biological matrices relevant to bioanalysis and the sampling methods,clinical pharmacokinetics,and therapeutic drug monitoring of different TKIs.This paper provides a comprehensive overview of the advancements in pretreatment methods,such as protein precipitation(PPT),liquid-liquid extraction(LLE),solid-phase extraction(SPE),micro-SPE(p-SPE),magnetic SPE(MSPE),and vortex-assisted dispersive SPE(VA-DSPE)achieved since 2017.It also highlights the latest analysis techniques such as newly developed high performance liquid chromatography(HPLC)and high-resolution mass spectrometry(HRMS)methods,capillary electro-phoresis(CE),gas chromatography(GC),supercritical fluid chromatography(SFC)procedures,surface plasmon resonance(SPR)assays as well as novel nanoprobes-based biosensing techniques.In addition,a comparison is made between the advantages and disadvantages of different approaches while pre-senting critical challenges and prospects in pharmacokinetic studies and therapeutic drug monitoring.
3.Impact of SARS-CoV-2 infection on graft composition and early transplant outcomes following allogeneic hematopoietic stem cell transplantation.
Fan LIN ; Hui SUN ; Yao CHEN ; Yuan Yuan ZHANG ; Jing LIU ; Yun HE ; Feng Mei ZHENG ; Zheng Li XU ; Feng Rong WANG ; Jun KONG ; Zhi Dong WANG ; Yuan Yuan WAN ; Xiao Dong MO ; Yu WANG ; Yi Fei CHENG ; Xiao Hui ZHANG ; Xiao Jun HUANG ; Lan Ping XU
Chinese Journal of Hematology 2023;44(11):890-899
Objective: To assess the feasibility of using donors with novel coronavirus disease 2019 (COVID-19) for allogeneic hematopoietic stem cell transplantation (allo-HSCT) when there are no other available donors and allo-HSCT cannot be delayed or discontinued. Methods: Seventy-one patients with malignant hematological diseases undergoing allo-HSCT between December 8, 2022, and January 10, 2023, were included. Of these, 16 received grafts from donors with mild COVID-19 (D-COVID(+) group) and 55 received grafts from donors without COVID-19 (D-COVID(-) group). The graft compositions were compared between the two groups. Engraftment, acute graft-versus-host disease (aGVHD), overall survival (OS), and relapse were also evaluated. Results: There were no serious side effects or adverse events in the D-COVID(+) group. The mononuclear cell dose and CD34(+) cell dose were comparable between the two groups, and no additional apheresis was required. There were no significant differences in the lymphocyte, monocyte, and T-cell subset doses between the two groups. The median natural killer cell dose in the D-COVID(+) group was significantly higher than that in the D-COVID(-) group (0.69×10(8)/kg vs. 0.53×10(8)/kg, P=0.031). The median follow-up time was 72 (33-104) days. All patients achieved primary engraftment. The 60-day platelet engraftment rates in the D-COVID(+) and D-COVID(-) groups were 100% and (96.4±0.2) %, respectively (P=0.568). There were no significant differences in neutrophil (P=0.309) and platelet (P=0.544) engraftment times. The cumulative incidence of grade 2-4 aGVHD was (37.5±1.6) % vs. (16.4±0.3) % (P=0.062), and of grade 3-4 aGVHD was 25.0% ±1.3% vs. 9.1% ±0.2% (P=0.095) in the D-COVID(+) and D-COVID(-) groups, respectively. The probabilities of 60-day OS were 100% and 98.1% ±1.8% (P=0.522) in the D-COVID(+) and D-COVID(-) groups, respectively. There was no relapse of primary disease during the study period. Conclusion: When allo-HSCT cannot be delayed or discontinued and no other donor is available, a donor with mild COVID-19 should be considered if tolerable. Larger sample sizes and longer follow-up periods are required to validate these results.
Humans
;
COVID-19
;
SARS-CoV-2
;
Hematopoietic Stem Cell Transplantation
;
Tissue Donors
;
Graft vs Host Disease
4.Clinical analysis of the usefulness of letermovir for prevention of cytomegalovirus infection after haploidentical hematopoietic stem cell transplantation.
Rui MA ; Yun HE ; Hui Fang WANG ; Lu BAI ; Wei HAN ; Yi Fei CHENG ; Kai Yan LIU ; Lan Ping XU ; Xiao Hui ZHANG ; Yu WANG ; Yuan Yuan ZHANG ; Feng Rong WANG ; Xiao Dong MO ; Chen Hua YAN ; Xiao Jun HUANG ; Yu Qian SUN
Chinese Journal of Internal Medicine 2023;62(7):826-832
Objective: To analyze the efficacy and safety of letermovir in primary prophylaxis of cytomegalovirus (CMV) reactivation in patients receiving haploidentical hematopoietic stem cell transplantation. Methods: This retrospective, cohort study was conducted using data of patients who underwent haploidentical transplantation at Peking University Institute of Hematology and received letermovir for primary prophylaxis between May 1, 2022 and August 30, 2022. The inclusion criteria of the letermovir group were as follows: letermovir initiation within 30 days after transplantation and continuation for≥90 days after transplantation. Patients who underwent haploidentical transplantation within the same time period but did not receive letermovir prophylaxis were selected in a 1∶4 ratio as controls. The main outcomes were the incidence of CMV infection and CMV disease after transplantation as well as the possible effects of letermovir on acute graft versus host disease (aGVHD), non-relapse mortality (NRM), and bone marrow suppression. Categorical variables were analyzed by chi-square test, and continuous variables were analyzed by Mann-Whitney U test. The Kaplan-Meier method was used for evaluating incidence differences. Results: Seventeen patients were included in the letermovir prophylaxis group. The median patient age in the letermovir group was significantly greater than that in the control group (43 yr vs. 15 yr; Z=-4.28, P<0.001). The two groups showed no significant difference in sex distribution and primary diseases, etc. (all P>0.05). The proportion of CMV-seronegative donors was significantly higher in the letermovir prophylaxis group in comparison with the control group (8/17 vs. 0/68, χ2=35.32, P<0.001). Three out of the 17 patients in the letermovir group experienced CMV reactivation, which was significantly lower than the incidence of CMV reactivation in the control group (3/17 vs. 40/68, χ2=9.23, P=0.002), and no CMV disease development observed in the letermovir group. Letermovir showed no significant effects on platelet engraftment (P=0.105), aGVHD (P=0.348), and 100-day NRM (P=0.474). Conclusions: Preliminary data suggest that letermovir may effectively reduce the incidence of CMV infection after haploidentical transplantation without influencing aGVHD, NRM, and bone marrow suppression. Prospective randomized controlled studies are required to further verify these findings.
Humans
;
Cytomegalovirus
;
Retrospective Studies
;
Cohort Studies
;
Prospective Studies
;
Cytomegalovirus Infections/prevention & control*
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Hematopoietic Stem Cell Transplantation/adverse effects*
;
Graft vs Host Disease/prevention & control*
;
Recurrence
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Antiviral Agents/therapeutic use*
5.Antimicrobial susceptibility of Gram-positive organisms:Results from China antimicrobial resistance surveillance trial(CARST)program,2021-2022
Yun LI ; Bo ZHENG ; Feng XUE ; Xiu-Zhen ZHANG ; Yun-Jian HU ; Yu-Fen JIN ; Jian-Hong ZHAO ; Shi-Yang PAN ; Wei GUO ; Feng ZHAO ; Yun-Song YU ; Xuan CAI ; Wen-En LIU ; De-Hua LIU ; Ying FEI ; Jia-Yun LIU ; Feng-Yan PEI ; Ling MENG ; Ping JI ; Jin TANG ; Kai XU ; Lei ZHU ; Cun-Wei CAO ; He-Ping XU ; Shan WANG ; Lan-Qing CUI ; Jia ZHANG ; Yao-Yao LIU
The Chinese Journal of Clinical Pharmacology 2023;39(23):3509-3524
Objective To investigate the Gram-positive coccus resistance in nationwide's tertiary hospitals and understand the trend of antimicrobial resistance.Methods All the clinical isolates were collected from 19 hospitals and the minimal inhibitory concentrations(MICs)were tested using agar/broth dilution method recommended.Results A total of 1 974 pathogenic Gram-positive coccus from 19 tertiary hospitals in 19 cities nationwide over the period from July 2021 to June 2022 were studied.Based on the MIC results,the prevalence of methicillin resistant Stapylococcus aureus(MRSA)and methicillin resistant Stapylococcus epidermidis(MRSE)were 36.4%and 79.9%respectively.No vancomycin insensitivity Staphylococcus was detected.Staphylococcus aureus were 100%susceptibility to linezolid and teicoplanin.Antibiotic resistance rate of Enterococcus faecalis and Enterococcus faecium to ampicillin were 3.1%and 92.9%.The detectation rate of vancomycin resistant Enterococcus(VRE)was 1.6%.Nonsusceptibility rate of Enterococcus faecalis to linezolid was 32.2%,two consecutive monitoring rises and nonsusceptibility rate of Enterococcus faecium(12.5%)was also significantly increased.The prevalence of penicillin non-susceptible Streptococcus pneumoniae(PNSSP)was 0.8%based on non-meningitis and parenteral administration criterion,decrease of nearly 30 percentage points from the previous surveillance.While for cases of oral penicillin,the rate was 71.8%,showing similar to last time.The results indicated that the number of strains with higher MIC value of penicillin(MIC ≥4 mg·L-1)decreased significantly.There were no significant differences of resistance rates of Stapylococcus aureus,Stapylococcus epidermidis,Enterococcus faecalis,Enterococcus faecium and Streptococcus pneumoniae among various groups such as different department,age,or specimen source.Conclusion VRE detection ratio stablized at a relatively low level.The number of Streptococcus pneumoniae with higher MIC value of penicillin decreased significantly compared with the previous monitoring.The increase of linezolidin-insensitive Enterococcus was noteworthy.
6.Antimicrobial susceptibility of Gram-negative organisms:Results from China antimicrobial resistance surveillance trial(CARST)program,2021-2022
Yun LI ; Bo ZHENG ; Feng XUE ; Xiu-Zhen ZHANG ; Yun-Jian HU ; Yu-Fen JIN ; Jian-Hong ZHAO ; Shi-Yang PAN ; Wei GUO ; Feng ZHAO ; Yun-Song YU ; Xuan CAI ; Wen-En LIU ; De-Hua LIU ; Ying FEI ; Jia-Yun LIU ; Feng-Yan PEI ; Ling MENG ; Ping JI ; Jin TANG ; Kai XU ; Lei ZHU ; Cun-Wei CAO ; He-Ping XU ; Shan WANG ; Lan-Qing CUI ; Jia ZHANG ; Yao-Yao LIU
The Chinese Journal of Clinical Pharmacology 2023;39(23):3525-3544
Objective To investigate the Gram-negative bacteria resistance in nationwide's tertiary hospitals and understand the trend of antimicrobial resistance.Method All the clinical isolates were collected from 19 hospitals and the minimal inhibitory concentrations(MICs)were tested using agar/broth dilution method recommended.Results A total of 4 066 pathogenic isolates from 19 tertiary hospitals in 19 cities nationwide over the period from July 2021 to June 2022 were studied.Based on the MIC results,Escherichia coli and Klebsiella pneumoniae showed extended spectrum β-lactamase(ESBLs)phenotype rates of 55.0%and 21.0%,respectively,ESBLs phenotype rate of Klebsiella pneumoniae keep going down.The ratios of carbapenems resistance Klebsiella pneumoniae increased by 5 percentage points compared with the previous monitoring.Carbapenems,moxalactam,sitafloxacin,β-lactam combination agents,fosfomycin trometamol,and amikacin displayed desirable antibacterial activity against Enterbacterales,susceptibal rates were above 75%.In addition,tigacycline,omacycline,colistin and fluoxefin maintained good antibacterial activity against their respective effective bacteria/species,and the bacterial sensitivity rates by more than 80%.Resistance rates of Pseudomonas aeruginosa and Acinetobacter baumannnii to imipenem were 26.3%and 72.1%and multidrug-resistant(MDR)detection rates were 41.1%and 77.3%,extensively drug-resistant(XDR)were 12.0%and 71.8%,respectively.Comparison of drug resistance rates from different wards,ages and specimen sources indicated that the proportion of resistance in Klebsiella pneumoniae and Acinetobacter baumannii isolated from intensive care unit(ICU)were significantly higher than non-ICU.Carbapenem resistance rates of Klebsiella pneumoniae isolated from ICU were more than 35%.Resistance rates of Haemophilus influenzae isolated in children to β-lactam,macrolide,clindamycin and ESBLs detection rate in Klebsiella pneumoniae isolated from children were more than those from adults and the old people,so bacterial resistance in children is an important problem in China.Conclusion ESBLs detection rate of Escherichia coli increased slightly after years of continuous decline.The proportion of carbapenem resistant Pseudomonas aeruginosa was stable,but the resistance rate of Klebsiella pneumoniae and Acinetobacter baumannii to carbapenems was still increased,which should be paid more attention.
7.A multicenter epidemiological study of acute bacterial meningitis in children.
Cai Yun WANG ; Hong Mei XU ; Jiao TIAN ; Si Qi HONG ; Gang LIU ; Si Xuan WANG ; Feng GAO ; Jing LIU ; Fu Rong LIU ; Hui YU ; Xia WU ; Bi Quan CHEN ; Fang Fang SHEN ; Guo ZHENG ; Jie YU ; Min SHU ; Lu LIU ; Li Jun DU ; Pei LI ; Zhi Wei XU ; Meng Quan ZHU ; Li Su HUANG ; He Yu HUANG ; Hai Bo LI ; Yuan Yuan HUANG ; Dong WANG ; Fang WU ; Song Ting BAI ; Jing Jing TANG ; Qing Wen SHAN ; Lian Cheng LAN ; Chun Hui ZHU ; Yan XIONG ; Jian Mei TIAN ; Jia Hui WU ; Jian Hua HAO ; Hui Ya ZHAO ; Ai Wei LIN ; Shuang Shuang SONG ; Dao Jiong LIN ; Qiong Hua ZHOU ; Yu Ping GUO ; Jin Zhun WU ; Xiao Qing YANG ; Xin Hua ZHANG ; Ying GUO ; Qing CAO ; Li Juan LUO ; Zhong Bin TAO ; Wen Kai YANG ; Yong Kang ZHOU ; Yuan CHEN ; Li Jie FENG ; Guo Long ZHU ; Yan Hong ZHANG ; Ping XUE ; Xiao Qin LI ; Zheng Zhen TANG ; De Hui ZHANG ; Xue Wen SU ; Zheng Hai QU ; Ying ZHANG ; Shi Yong ZHAO ; Zheng Hong QI ; Lin PANG ; Cai Ying WANG ; Hui Ling DENG ; Xing Lou LIU ; Ying Hu CHEN ; Sainan SHU
Chinese Journal of Pediatrics 2022;60(10):1045-1053
Objective: To analyze the clinical epidemiological characteristics including composition of pathogens , clinical characteristics, and disease prognosis acute bacterial meningitis (ABM) in Chinese children. Methods: A retrospective analysis was performed on the clinical and laboratory data of 1 610 children <15 years of age with ABM in 33 tertiary hospitals in China from January 2019 to December 2020. Patients were divided into different groups according to age,<28 days group, 28 days to <3 months group, 3 months to <1 year group, 1-<5 years of age group, 5-<15 years of age group; etiology confirmed group and clinically diagnosed group according to etiology diagnosis. Non-numeric variables were analyzed with the Chi-square test or Fisher's exact test, while non-normal distrituction numeric variables were compared with nonparametric test. Results: Among 1 610 children with ABM, 955 were male and 650 were female (5 cases were not provided with gender information), and the age of onset was 1.5 (0.5, 5.5) months. There were 588 cases age from <28 days, 462 cases age from 28 days to <3 months, 302 cases age from 3 months to <1 year of age group, 156 cases in the 1-<5 years of age and 101 cases in the 5-<15 years of age. The detection rates were 38.8% (95/245) and 31.5% (70/222) of Escherichia coli and 27.8% (68/245) and 35.1% (78/222) of Streptococcus agalactiae in infants younger than 28 days of age and 28 days to 3 months of age; the detection rates of Streptococcus pneumonia, Escherichia coli, and Streptococcus agalactiae were 34.3% (61/178), 14.0% (25/178) and 13.5% (24/178) in the 3 months of age to <1 year of age group; the dominant pathogens were Streptococcus pneumoniae and the detection rate were 67.9% (74/109) and 44.4% (16/36) in the 1-<5 years of age and 5-<15 years of age . There were 9.7% (19/195) strains of Escherichia coli producing ultra-broad-spectrum β-lactamases. The positive rates of cerebrospinal fluid (CSF) culture and blood culture were 32.2% (515/1 598) and 25.0% (400/1 598), while 38.2% (126/330)and 25.3% (21/83) in CSF metagenomics next generation sequencing and Streptococcus pneumoniae antigen detection. There were 4.3% (32/790) cases of which CSF white blood cell counts were normal in etiology confirmed group. Among 1 610 children with ABM, main intracranial imaging complications were subdural effusion and (or) empyema in 349 cases (21.7%), hydrocephalus in 233 cases (14.5%), brain abscess in 178 cases (11.1%), and other cerebrovascular diseases, including encephalomalacia, cerebral infarction, and encephalatrophy, in 174 cases (10.8%). Among the 166 cases (10.3%) with unfavorable outcome, 32 cases (2.0%) died among whom 24 cases died before 1 year of age, and 37 cases (2.3%) had recurrence among whom 25 cases had recurrence within 3 weeks. The incidences of subdural effusion and (or) empyema, brain abscess and ependymitis in the etiology confirmed group were significantly higher than those in the clinically diagnosed group (26.2% (207/790) vs. 17.3% (142/820), 13.0% (103/790) vs. 9.1% (75/820), 4.6% (36/790) vs. 2.7% (22/820), χ2=18.71, 6.20, 4.07, all P<0.05), but there was no significant difference in the unfavorable outcomes, mortility, and recurrence between these 2 groups (all P>0.05). Conclusions: The onset age of ABM in children is usually within 1 year of age, especially <3 months. The common pathogens in infants <3 months of age are Escherichia coli and Streptococcus agalactiae, and the dominant pathogen in infant ≥3 months is Streptococcus pneumoniae. Subdural effusion and (or) empyema and hydrocephalus are common complications. ABM should not be excluded even if CSF white blood cell counts is within normal range. Standardized bacteriological examination should be paid more attention to increase the pathogenic detection rate. Non-culture CSF detection methods may facilitate the pathogenic diagnosis.
Adolescent
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Brain Abscess
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Child
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Child, Preschool
;
Escherichia coli
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Female
;
Humans
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Hydrocephalus
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Infant
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Infant, Newborn
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Male
;
Meningitis, Bacterial/epidemiology*
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Retrospective Studies
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Streptococcus agalactiae
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Streptococcus pneumoniae
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Subdural Effusion
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beta-Lactamases
8.Novel Variants in the FIG4 Gene Associated With Chinese Sporadic Amyotrophic Lateral Sclerosis With Slow Progression
Chang-Yun LIU ; Ji-Lan LIN ; Shu-Yan FENG ; Chun-Hui CHE ; Hua-Pin HUANG ; Zhang-Yu ZOU
Journal of Clinical Neurology 2022;18(1):41-47
Background:
and Purpose Mutations in the FIG4 gene have been linked to amyotrophic lateral sclerosis (ALS) type 11 in Caucasian populations. The purpose of this study was to identify FIG4 variants in a cohort of 15 familial ALS (FALS) indexes and 275 sporadic ALS (SALS) patients of Han Chinese origin.
Methods:
All 23 exons of FIG4 were sequenced using targeted next-generation sequencing.An extensive literature review was performed to detect genotype-phenotype associations of FIG4 mutations.
Results:
No FIG4 variants were identified in the FALS patients. One novel heterozygous missense variant (c.352G>T [p.D118Y]) and one novel heterozygous nonsense variant (c.2158G>T [p.E720X]) in FIG4 were identified in two SALS patients. The p.E720X variant is interpreted as likely pathogenic while the p.D118Y variant is a variant of uncertain significance. The patient carrying the p.E720X mutation developed lower-limb-onset slowly progressive ALS, and survived for 11.5 years. The patient harboring the FIG4 p.D118Y variant also presented with progressive ALS, with the score on the ALS Functional Rating Scale–Revised (ALSFRS-R) decreasing by 0.4 per month. The rate of decrease in the ALSFRS-R scores from symptom onset to diagnosis seemed to be lower in the patients carrying FIG4 variants than the no-FIG4-mutation ALS patients in this study.
Conclusions
Our findings suggest that ALS patients carrying FIG4 mutations are not common in the Chinese population and are more likely to exhibit slow progression.
9.Course of disease and related epidemiological parameters of COVID-19: a prospective study based on contact tracing cohort.
Yan ZHOU ; Wen Jia LIANG ; Zi Hui CHEN ; Tao LIU ; Tie SONG ; Shao Wei CHEN ; Ping WANG ; Jia Ling LI ; Yun Hua LAN ; Ming Ji CHENG ; Jin Xu HUANG ; Ji Wei NIU ; Jian Peng XIAO ; Jian Xiong HU ; Li Feng LIN ; Qiong HUANG ; Ai Ping DENG ; Xiao Hua TAN ; Min KANG ; Gui Min CHEN ; Mo Ran DONG ; Hao Jie ZHONG ; Wen Jun MA
Chinese Journal of Preventive Medicine 2022;56(4):474-478
Objective: To analyze the course of disease and epidemiological parameters of COVID-19 and provide evidence for making prevention and control strategies. Methods: To display the distribution of course of disease of the infectors who had close contacts with COVID-19 cases from January 1 to March 15, 2020 in Guangdong Provincial, the models of Lognormal, Weibull and gamma distribution were applied. A descriptive analysis was conducted on the basic characteristics and epidemiological parameters of course of disease. Results: In total, 515 of 11 580 close contacts were infected, with an attack rate about 4.4%, including 449 confirmed cases and 66 asymptomatic cases. Lognormal distribution was fitting best for latent period, incubation period, pre-symptomatic infection period of confirmed cases and infection period of asymptomatic cases; Gamma distribution was fitting best for infectious period and clinical symptom period of confirmed cases; Weibull distribution was fitting best for latent period of asymptomatic cases. The latent period, incubation period, pre-symptomatic infection period, infectious period and clinical symptoms period of confirmed cases were 4.50 (95%CI:3.86-5.13) days, 5.12 (95%CI:4.63-5.62) days, 0.87 (95%CI:0.67-1.07) days, 11.89 (95%CI:9.81-13.98) days and 22.00 (95%CI:21.24-22.77) days, respectively. The latent period and infectious period of asymptomatic cases were 8.88 (95%CI:6.89-10.86) days and 6.18 (95%CI:1.89-10.47) days, respectively. Conclusion: The estimated course of COVID-19 and related epidemiological parameters are similar to the existing data.
COVID-19
;
Cohort Studies
;
Contact Tracing
;
Humans
;
Incidence
;
Prospective Studies
10.Preliminary study on centrifugation time of liquid plasmatrix for soft tissue regeneration.
Meng Ge FENG ; Yu Lan WANG ; Yun Xiao WANG ; Yu Feng ZHANG
Chinese Journal of Stomatology 2022;57(4):366-374
Objective: To provide reference for clinical application of liquid plasmatrix, and to investigate the optimal centrifugation time of liquid plasmatrix prepared by horizontal centrifugation for soft tissue regeneration from the aspects of mechanical properties, biological properties, and the effect of promoting soft tissue regeneration. Methods: Venous blood was collected from 6 healthy volunteers [3 males and 3 females, aged (26±2) years, with informed consent] who volunteered to donate blood at School of Stomatology, Wuhan University from September to November 2021. The collected venous blood was centrifuged at 500 ×g for 3, 5, 8 and 12 min to obtain liquid plasmatrix. The volume, weight, solidification time, and mechanical properties of liquid plasmatrix prepared at different centrifugation time were measured and recorded (the sample size at each time point was 3). The microstructure of different groups of liquid plasmatrix clot was observed by scanning electron microscope (SEM). The rheological properties of each group of liquid plasmatrix clot were measured by rheological test. The number and concentration of cells in the whole blood group and in each liquid plasmatrix group were measured using complete blood count test. The distribution of cells in the liquid plasmatrix clots was observed by hematoxylin-eosin staining. The effect of control group (Dulbecco's modified Eagle's medium containing 20% fetal bovine serum) and liquid plasmatrix clot exudates in 3, 5, 8, 12 min group (the sample size at each time point was 3) on gingival fibroblast migration was detected by cell migration method. Finally, the effects of control group and liquid plasmatrix clot exudates on the morphology of gingival fibroblasts were observed by fluorescence microscope. Results: The volume of liquid plasmatrix in 3, 5, 8 and 12 min group were approximately (2.47±0.12), (2.67±0.12), (3.53±0.12) and (3.73±0.12) ml, respectively. The weight of liquid plasmatrix in 3, 5, 8 and 12 min group were approximately (0.35±0.01), (0.46±0.02), (0.88±0.06) and (1.03±0.01) g, respectively. The maximum tensile force of liquid plasmatrix clots in 3, 5, 8 and 12 min group were (0.55±0.03), (0.56±0.03), (1.31±0.05) and (1.38±0.02) N, respectively. SEM results showed that the fibers inside the liquid plasmatrix clot became denser with increased centrifugation time. Compared with other groups, the concentrations of leukocytes, neutrophils, monocytes and lymphocytes in 8 min group were the highest, and the distribution of cell was more even. Compared with other groups, the efficiency of stimulating gingival fibroblast migration in 8 min group was the best (1.60±0.01). Fluorescence staining test showed that the liquid plasmatrix clot exudates could make gingival fibroblasts more stretched compared with control group. Conclusions: The present study shows that liquid plasmatrix prepared by centrifugation with 500 ×g centrifugal force for 8 min has higher concentration of viable cells and the ability to promote the migration of gingival fibroblasts.
Cell Movement
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Centrifugation/methods*
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Female
;
Fibroblasts
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Gingiva
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Humans
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Male
;
Wound Healing

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