BACKGROUND:Due to the sudden release and the rapid removal by proteases,platelet-rich plasma hydrogel leads to shorter residence times of growth factors at the wound site.In recent years,researchers have focused on the use of hydrogels to encapsulate platelet-rich plasma in order to improve the deficiency of platelet-rich plasma hydrogels. OBJECTIVE:To prepare self-assembled polypeptide-platelet-rich plasma hydrogel and to explore its effects on the release of bioactive factors of platelet-rich plasma. METHODS:The self-assembled polypeptide was synthesized by the solid-phase synthesis method,and the solution was prepared by D-PBS.Hydrogels were prepared by mixing different volumes of polypeptide solutions with platelet-rich plasma and calcium chloride/thrombin solutions,so that the final mass fraction of polypeptides in the system was 0.1%,0.3%,and 0.5%,respectively.The hydrogel state was observed,and the release of growth factors in platelet-rich plasma was detected in vitro.The polypeptide self-assembly was stimulated by mixing 1%polypeptide solution with 1%human serum albumin solution,so that the final mass fraction of the polypeptide was 0.1%,0.3%,and 0.5%,respectively.The flow state of the liquid was observed,and the rheological mechanical properties of the self-assembled polypeptide were tested.The microstructure of polypeptide(mass fraction of 0.1%and 0.001%)-human serum albumin solution was observed by scanning electron microscope and transmission electron microscope. RESULTS AND CONCLUSION:(1)Hydrogels could be formed between different volumes of polypeptide solution and platelet-rich plasma.Compared with platelet-rich plasma hydrogels,0.1%and 0.3%polypeptide-platelet-rich plasma hydrogels could alleviate the sudden release of epidermal growth factor and vascular endothelial growth factor,and extend the release time to 48 hours.(2)After the addition of human serum albumin,the 0.1%polypeptide group still exhibited a flowing liquid,the 0.3%polypeptide group was semi-liquid,and the 0.5%polypeptide group stimulated self-assembly to form hydrogel.It was determined that human serum albumin in platelet-rich plasma could stimulate the self-assembly of polypeptides.With the increase of the mass fraction of the polypeptide,the higher the storage modulus of the self-assembled polypeptide,the easier it was to form glue.(3)Transmission electron microscopy exhibited that the polypeptide nanofibers were short and disordered before the addition of human serum albumin.After the addition of human serum albumin,the polypeptide nanofibers became significantly longer and cross-linked into bundles,forming a dense fiber network structure.Under a scanning electron microscope,the polypeptides displayed a disordered lamellar structure before adding human serum albumin.After the addition of human serum albumin,the polypeptides self-assembled into cross-linked and densely arranged porous structures.(4)In conclusion,the novel polypeptide can self-assemble triggered by platelet-rich plasma and the self-assembly effect can be accurately adjusted according to the ratio of human serum albumin to polypeptide.This polypeptide has a sustained release effect on the growth factors of platelet-rich plasma,which can be used as a new biomaterial for tissue repair.

As the most commonly used antipyretic and analgesic drug,paracetamol(PA)coexists with neuro-transmitter dopamine(DA)in real biological samples.Their simultaneous determination is extremely important for human health,but they also interfere with each other.In order to improve the conductivity,adsorption affinity,sensitivity,and selectivity of TiO2-based electrochemical sensor,N-doped carbon@-TiO2 double-shelled hollow sphere(H-C/N@TiO2)is designed and synthesized by simple alcoholic and hydrothermal method,using polystyrene sphere(PS)as a template.Meanwhile,TiO2 hollow spheres(H-TiO2)or N-doped carbon hollow spheres(H-C/N)are also prepared by the same method.H-C/N@TiO2 has good conductivity,charge separation,and the highly enhanced and stable current responses for the detection of PA and DA.The detection limit and linear range are 50.0 nmol/L and 0.3-50 μmol/L for PA,40.0 nmol/L and 0.3-50 μmol/L for DA,respectively,which are better than those of carbon-based sen-sors.Moreover,this electrochemical sensor,with high selectivity,strong anti-interference,high reli-ability,and long time durability,can be used for the simultaneous detection of PA and DA in human blood serum and saliva.The high electrochemical performance of H-C/N@TiO2 is attributed to the multi-functional combination of different layers,because of good conductivity,absorption and electrons transfer ability from in-situ N-doped carbon and electrocatalytic activity from TiO2.

OBJECTIVE: To analyze the molecular etiology of a Chinese child affected with dihydropyrimidinase deficiency. METHODS: Genomic DNA was extracted from peripheral blood samples of the family members. Pathogenic variant was determined by whole exome sequencing and verified by Sanger sequencing. RESULTS: The child was found to harbor homozygous c.905G>A (p.Arg302Gln) variants in exon 5 of the DPYS gene, for which her parents were both heterozygous carriers. CONCLUSION The homozygous c.905G>A (p.Arg302Gln) variants of the DPYS gene probably underlies the dihydropyrimidinase deficiency in the child. Above result has enabled genetic counseling and prenatal diagnosis for this family.
Amidohydrolases/genetics* ; Asian Continental Ancestry Group/genetics* ; Child ; Exons ; Female ; Humans ; Metabolism, Inborn Errors/genetics* ; Mutation ; Pedigree

Objective To investigate the epidemic characteristics of pregnancy hypothyroidism combined with preeclampsia (PE) in Tongzhou District of Beijing from 2015 to 2019, analyze the influencing factors, and provide a reference for the development of scientific prevention and control measures. Methods A descriptive epidemiological method was used to analyze the data. The incidence rate of pregnancy hypothyroidism combined with PE and related epidemiological survey data from 2015 to 2019 in Tongzhou District of Beijing were analyzed. Logistic regression equation was established to analyze its related factors. SPSS 20 was used for t test, rank sum test and Spearman rank correlation test with a test significance level of 0.05. Results In 2015-2019, there were 267 pregnant women with PE in Luhe hospital, maternal and child health care hospital, Tongzhou District second hospital, Tongzhou District Third Hospital, No.263 Hospital of PLA and Zhang Jia Wan hospital in Tongzhou District of Beijing. The average annual incidence rate of hypothyroidism combined with PE in pregnant women was 0.07% (267/5/77 015), and varied each year. A questionnaire survey was conducted on the 267 cases by the investigation team. A total of 262 valid data sheets were recovered after removing residual pages, repeated samples and unqualified questionnaires. The incidence of hypothyroidism combined with PE was higher in women aged ≤ 20 years and 35-45 years, in rural areas, and with an education level below high school, family monthly income ≤ 3 000 yuan, multiple births, and more pregnancy complications than that in women aged 21-34 years, in urban areas, and with an education level of high school or above, family monthly income > 3 000 yuan, singleton, and fewer pregnancy complications (P < 0.05). Age, household registration, education level and family income were the risk factors of pregnancy hypothyroidism combined with PE. Conclusion The incidence trend of pregnancy hypothyroidism combined with PE was not stable in Tongzhou District of Beijing from 2015 to 2019, showing strong differences in age, education level, economic level, pregnancy and childbirth times, BMI, and pregnancy complications. It is necessary to fully understand the physical conditions of pregnant women, and to establish a comprehensive prevention and control system.

Objective:To investigate the relationship between the changes of inflammatory cytokine levels and prognosis of patients with critical coronavirus disease 2019 (COVID-19) undergoing invasive mechanical ventilation (IMV).Methods:A retrospective study was conducted. The clinical date of critical COVID-19 patients undergoing IMV who were hospitalized in Wuhan Union Hospital, Tongji Medical College of Huazhong University of Science and Technology from February 4th to March 25th in 2020 were collected. At the same time, the inflammatory cytokine levels including interleukins (IL-2, IL-4, IL-6, IL-10) and tumor necrosis factor-α (TNF-α) at 48 hours before IMV and 48 hours after IMV of all the patients, as well as the 48 hours after weaning or right before death were recorded. Multivariate unconditional Logistic regression analysis was used to screen the independent risk factors of death during hospitalization.Results:Among the 43 patients, 13 patients improved and 30 died. Compared with the survival group, the patients in the non-survival group were older (years old: 67.6±7.3 vs. 58.5±11.9, P < 0.05), with higher rates of hypertension, diabetes and coronary heart disease (53.3% vs. 15.4%, 63.3% vs. 23.1%, 26.7% vs. 0%, all P < 0.05), and the time from onset to admission to hospital, admission to ICU and IMV were longer (days: it was 9.17±5.00 vs. 5.07±2.49, 17.10±7.11 vs. 12.23±5.05, and 17.90±7.46 vs. 12.61±5.60, respectively, all P < 0.05). The IL-6 and TNF-α levels on 48 hours after IMV in the non-survival patients increased significantly as compared with those before 48 hours and the surviving patients. Especially, the IL-6 levels increased significantly as compared with those at 48 hours after IMV and 48 hours after weaning in the surviving patients [ng/L: 800.00 (194.25, 2 000.00) vs. 22.03 (6.66, 28.21), 3 204.00 (1 264.88, 5 000.00) vs. 5.00 (3.98, 12.27), both P < 0.01]. The IL-10 level before death in the non-survival patients increased significantly as compared with that at 48 hours after weaning in the surviving patients [ng/L: 55.89 (26.07, 100.14) vs. 3.53 (2.76, 12.36), P < 0.05]. There were no significant differences in the levels of IL-2 and IL-4 between the two groups at every time point. The variables of age, basic diseases, the IL-6 level after IMV were included in the multivariate unconditional Logistic regression analysis, which showed that age [odds ratio ( OR) = 0.821, 95% confidence interval (95% CI) was 0.695-0.968], hypertension ( OR = 0.027, 95% CI was 0.002-0.378), diabetes mellitus ( OR = 0.054, 95% CI was 0.005-0.611), coronary heart disease ( OR = 0.042, 95% CI was 0.002-0.968) and the IL-6 level after IMV ( OR = 0.902, 95% CI was 0.819-0.994) were independent risk factors for death during hospitalization in patients with critical COVID-19 undergoing IMV (all P < 0.05). Conclusions:The levels of inflammatory cytokine including IL-6, IL-10, and TNF-α increased significantly with aggravation in critical COVID-19 patients undergoing IMV, especially IL-6. IL-6 was an independent risk factor for death of critical COVID-19 patients undergoing IMV.

Objective To explore the changes of serum vascular endothelial growth factor ( VEGF) and endostatin (ES) in patients with polycystic ovary syndrome (PCOS) and their effects on the ovarian stromal blood flow. Methods From January 2015 to January 2017,sixty cases diagnosed with polycystic ovary syndrome in the Eighth Affiliated Hospital of Sun Yat?sen University were selected into the observation group,and other 60 cases of healthy women with normal menstrual cycle in the same period were selected as the control group. Then, the levels of serum VEGF and ES of the two groups were observed, the patients in the early ovarian follicular blood flow changes were monitored by transvaginal color Doppler ultrasound to observe the bilateral ovaries and the hemodynamic indexes. Hemodynamic indexes (pulsatility index and resistance index) were compared,and the effects of serum VEGF and endostatin levels on ovarian interstitial blood flow were analyzed. Results The PI and RI of the observation group were(1. 3±0. 2) and (0. 5±0. 1),the PI and RI of the control group were (2. 4±0. 4)and(1. 0±0. 1),the differences were statistically significant(t=2. 378,2. 578,P=0. 023,0. 014);the levels of VEGF and ES in the observation group were (1083±167)ng/L and (278±23)ng/L,the levels of VEGF and ES in the control group were (625±71) ng/L and (172±21)ng/L,the differences were statistically significant( t=2. 123,2. 892,P=0. 042,0. 008);there was negative correlation among VEGF and PI and RI ( r=-0. 770,-0. 782,P<0. 01);there was negative correlation among ES and PI and RI ( r=-0. 751,-0. 799,P<0. 01);there was positive correlation between VEGF and ES ( r=0. 552,P<0. 01) . Conclusion The serum levels of VEGF and ES are significantly increase in patients with polycystic ovary syndrome, the imbalance between the two expressions may play an important role in the increase of ovarian stromal blood flow.

OBJECTIVE:To establish a method for simultaneous determination of 6 residual organic solvents in aprepitant raw material as methanol,ethanol,acetone,isopropyl alcohol,methyl tert-butyl ether and tetrahydrofuran.METHODS:Headspace capillary gas chromatography was adopted.The determination was performed on DB-624 capillary column using temperature programming.The temperature of injector port was 180 ℃,and flame ionization detector was used with temperature of 260 ℃.Nitrogen was used as carrier gas with flow rate 3.0 mL/min.The spilt ratio was 5 ∶ 1,and head-space injection volume was 1.0 mL.The head-space equilibrium temperature was set at 80 ℃,and equilibrium time was 40 min.RESULTS:The linear ranges of methanol,ethanol,acetone,isopropyl alcohol,methyl tert-butyl ether,tetrahydrofuran were 6.052-605.232 μ g/mL (r=0.999 9),9.987-998.718 μg/mL(r=0.999 9),9.998-999.768 μg/mL(r=0.999 8),9.986-998.634 μg/mL(r=0.999 9),9.991-999.090 μg/mL (r=0.999 7),1.461-146.133 μg/mL(r=0.999 5),respectively.The limits of quantitation were 1.782 1,2.079 0,0.749 8,1.777 8,0.223 1,0.607 0 μg/mL;the limits of detection were 0.594 0,0.693 0,0.249 9,0.592 6,0.074 4,0.202 3 μg/mL,respectively.RSD of precision test was lower than 2.0％.Only acetone and isopropyl alcohol were detected in stability test and reproducibility tests,RSD＜2.0％.Their recoveries were 99.34-100.75％ (RSD=0.52％,n=9),98.20％-100.24％ (RSD=0.69％,n=9),98.07％-100.07％ (RSD=0.84％,n=9),99.86％-101.32％ (RSD=0.58％,n=9),97.87％-104.02％ (RSD=2.13％,n=9),98.26 ％-100.58 ％ (RSD =0.75 ％,n =9),respectively.CONCLUSIONS:The established method is simple,accurate and reproducible,and can be used for simultaneous determination of 6 residual organic solvents in aprepitant raw material.

Objective To investigate the prevalence of deep venous thrombosis (DVT) in burn patients,and to explore its influencing factors.Methods Clinical data of 2 506 burn patients admitted to our ward from January 2009 to January 2014,conforming to the study criteria,were retrospectively analyzed.Patients were divided into DVT group (n =26) and non-DVT group (n =2 480) according to whether or not DVT occurred during hospitalization.The incidence of DVT was calculated.The diagnosis time and type of DVT were recorded.The data of gender,age,depth of burn,total burn area,location of injury,cause of injury,infection of wound,venous transfusion of fluid (hypertonic solution and blood),location of intravenous catheterization,skin grafting,timing of first skin grafting after injury,D-dimer,bedridden duration after injury among patients between two groups were compared with chi-square test and Wilcoxon test.Indexes with statistically significant differences between two groups were selected,and they were processed with multivariate logistic stepwise regression analysis to screen the independent risk factors of DVT.Results (1) The incidence of DVT was 1.04％ (26/2 506).The diagnosis time of DVT was 16-62(40 ± 12)d,and patients diagnosed as having DVT after the 20th day post injury accounted for 92.3％ (24/26).All DVT occurred in lower limbs,with 1 case of central type,24 cases of peripheral type,and 1 case of mixed type.(2) There were no statistically significant differences in gender,location of injury (upper limbs,trunk,head and face),cause of injury,jugular vein catheterization,skin grafting,and timing of first skin grafting after injury among patients between two groups (withx 2 values from 1.853 to 3.742,Z =3.342,P values above 0.05).There were statistically significant differences in age,depth of burn,total burn area,burn in lower limbs,infection of wound,venous transfusion of hypertonic solution and blood,femoral vein and subclavian vein catheterization,D-dimer,and bedridden duration after injury among patients between two groups (with x2 values from 4.569 to 11.324,Zvalues respectively 7.357 and 7.012,P ＜0.05 orP ＜0.01).(3) Age,total burn area,burn in lower limbs,infection of wound,and D-dimer were the independent risk factors of DVT (with odds ratio respectively 2.904,2.655,3.574,2.786,3.142,95％ confidence interval respectively 1.504-7.652,1.368-6.594,1.958-8.511,1.459-7.001,1.922-8.062,P values below 0.05).Conclusions The incidence of DVT in burn patients is relatively low;it is diagnosed after the 20th day post injury in most patients,and the overwhelming majority is the peripheral type.Age,total burn area,burn in lower limbs,infection of wound,and D-dimer are the independent risk factors of DVT in burn patients,with which its occurrence could be predicted.

Objective To reversing methicillin-resistant Staphylococcus(MRS) to methicillin-susceptible Staphylococcus(MSS) by changing nutritional conditions and continuous transfer of culture .Methods MRS trains separating from clinical specimens were cultured in different conditions ,continuous cultural transfer ,and drug sensitive test were proceeded periodically to observe the phe-notypic and chemical reaction change of MRS .The mecA gene were detected of the original and mutant strains by polymerase chain reaction(PCR) ,then the gene sequenced and compared .Results 53 MRS strains were studied .6 strains were phenotype successful-ly converted to MSS in different cultural conditions ,among them mecA gene was undetected in 2 strains ,and down expressed in 4 strains .Conclusion The MRS strains separated from clinical specimens may revert to MSS by culture under different nutritional conditions .The mecA gene of MRS may be lost or lower expressed and the MRS and mutant strains may be different in genomics .

Objective To analyze effect of the syphilis prevention and control work among female sex workers(FSWs), and provide reference data for target intervention in Guangdong province.Methods Syphilis prevalence among FSWs from 2009 to 2013 were analyzed statistically based on the data from Guangdong Provincial high-risk groups in sexually transmit-ted infection(STI)control program.Results A total of 34 338 FSWs were detected,including 23 816(69.36%)FSWs at the high-tier venues,8 811(25.66%)middle-tier,and 1 711(4.98%)low tier.The syphilis prevalence of FSWs at high-, middle-,and low-tier venues in 2009 was 2.60%,7.36%,and 10.54% respectively,and in 2013 was 1.45%,2.75%,and 21.88% respectively.Chi-square test showed a downward trend in the prevalence of syphilis among the high and middle tier FSWs in 2009-2013(χ2 =12.807,52.333 respectively,both P <0.001),and remained high among FSWs at low-tier venues(χ2 =0.027,P =0.87).The difference in syphilis prevalence in 2013 among FSWs from different types of venues was statistically significant (χ2 =190.64,P <0.001 ).No significant difference in syphilis prevalence was found among FSWs from Pearl River Delta,eastern,western and northern Guangdong(χ2 =5.24,P =0.07).Conclusion Significant difference is found in prevalence of syphilis among FSWs from different types of settings.FSWs from low-tier settings have a relatively lower syphilis testing rate but with higher infection rate.