Polygonum cuspidatum polyketide synthase 1 (PcPKS1) has the catalytic activity of chalcone synthase (CHS) and benzylidene acetone synthase (BAS), which can catalyze the production of polyketides naringenin chalcone and benzylidene acetone, and then catalyze the synthesis of flavonoids or benzylidene acetone. In this study, three amino acid sites (Thr133, Ser134, Ser33) that may affect the function of PcPKS1 were identified by analyzing the sequences of PcPKS1, the BAS from Rheum palmatum and the CHS from Arabidopsis thaliana, as well as the conformation of the catalytic site of the enzyme. Molecular modification of PcPKS1 was carried out by site-directed mutagenesis, and two mutants were successfully obtained. The in vitro enzymatic reactions were carried out, and the differences in activity were detected by high performance liquid chromatography (HPLC). Finally, mutants T133LS134A and S339V with bifunctional activity were obtained. In addition to bifunctional activities of BAS and CHS, the modified PcPKS1 had much higher BAS activity than that of the wild type PcPKS1 under the conditions of pH 7.0 and pH 9.0, respectively. It provides a theoretical basis for future use of PcPKS1 in genetic engineering to regulate the biosynthesis of flavonoids and raspberry ketones.
Amino Acid Sequence ; Fallopia japonica/metabolism* ; Polyketide Synthases/chemistry* ; Acetone ; Mutagenesis, Site-Directed ; Flavonoids/metabolism* ; Acyltransferases/metabolism*

Objective:To explore the value of cardiovascular MR (CMR) T 1 mapping in evaluating myocardial injury in patients recovered from COVID-19. Methods:The clinical and image data of 15 patients with COVID-19 (9 with moderate clinical manifestation, 6 with severe clinical manifestation) who underwent CMR screening at 3 months after being discharged from the Second People′s Hospital of Fuyang City during May 2020 to June 2020 were prospective collected. Fifteen COVID-19 patients were selected as case group, and another 11 healthy volunteers were selected as control group. A standardized CMR protocol included cine, native and enhanced T 1 mapping, late gadolinium enhancement (LGE). Cardiac functional parameters, native T 1 value of left ventricular and extracellular volume fraction (ECV) were measured. One way ANOVA was used to assess the difference between CMR parameters among moderate and severe manifestation groups and control group, and LSD- t was used to assess the difference between the three groups. Results:LGE value was negative in all subjects. ECV values were higher in recovered COVID-19 patients with either moderate (27.9%±2.7%) or severe manifestation (30.0%±3.7%) than control group (23.2±1.9%) ( P<0.05); there was no significant difference of ECV values between recovered COVID-19 patients with moderate and severe manifestation ( P=0.100). There was no difference of native T 1 values and other functional and morphologic parameters of left ventricular and right ventricular among recovered COVID-19 patients with moderate and severe manifestation and control group ( P>0.05). Conclusion:CMR myocardial tissue ECV increase in patients who recovered from COVID-19, suggesting subclinical myocardial injury.

Objective:To analyze the clinical characteristics of patients with novel coronavirus pneumonia (COVID-19) and the factors influencing mild cases developing into severe cases, so as to provide a basis for clinical screening, prevention and treatment of potential severe cases.Methods:Retrospective analysis was performed on the clinical characteristics of 168 cases who were admitted to two tertiary general hospitals in Anhui province and diagnosed with COVID-19 from January 20 to March 4, 2020. According to the classification criteria in the COVID-19 diagnosis and treatment program (trial version 6) issued by the National Health Commission, the mild and common cases were classified as the mild group ( n=137), and the severe and critical cases were classified as the severe group ( n=31). The general data, epidemiological history, clinical manifestations, laboratory examination and imaging indexes of the two groups were compared. Univariate analysis was performed. Then multivariate Logistic regression analysis was conducted on the factors with statistically significant differences in univariate analysis to obtain independent influencing factors of the occurrence of severe COVID-19. Results:Among the 168 COVID-19 patients, 95 were male and 73 were female, with an average age of 42.6±15.8 years old. The mean age of the mild group was younger than that of the severe group (40.5±15.5 vs 51.6 ±14.1, P<0.01). The proportion of patients combined with hypertension (29.0% vs 10.9%), diabetes (25.8% vs 2.2%, P=0.005) and two or more underlying diseases (29.0% vs 4.4%, P=0.006) in the severe group were significantly higher than those in the mild group. In the severe group, the proportion of patients receiving initial treatment in Medical institutions below secondary hospitals was significantly higher than that in the mild group ( P<0.01), and the time between symptom onset and diagnosis was longer [(8.00±3.27) d vs (6.49±3.90) d, P=0.048]. There was no significant difference in the initial symptoms between the mild group and the severe group. However, the body temperature was higher in the severe group [(38.80±0.67)℃ vs (37.9±0.60)℃, P<0.01]. At the time of admission, the lymphocyte percentage of the severe group was significantly lower than that of the mild group [(18.20±9.13)% vs (24.43±10.43)%, P<0.01], while C-reactive protein, interleukin-6 (IL-6), D-dimer, LDH, aspartate and aminotransferase were significantly higher than that of the mild group ( P<0.01). CT imaging showed that 11 (8%) patients in the mild group had lesions confined to a single lobe of the lung, while all patients in the severe group had multi-lobe lesions ( P<0.01). All the 168 COVID-19 patients in this study were cured, and the length of hospital stay in the severe group was significantly longer than that in the mild group [(24.71±7.72) d vs (20.28±7.67) d, P=0.021]. According to multivariate binary Logistic regression analysis, age ( P=0.042), diabetes ( P=0.021), body temperature at admission ( P=0.001), and IL-6 measured at admission ( P=0.008) were independent factors affecting COVID-19 to severe progress. Conclusions:Strengthening the professional knowledge training of primary hospitals is helpful for early diagnosis of COVID-19. Patients with older age, combined with diabetes, high initial fever and significantly increased IL-6 level are more possibly to develop into severe disease. Early identification and prevention should be carried out.

Objective:To understand the situation supported by the National Natural Science Foundation in the field of occupational diseases (H2402) in China, so as to provide a reference basis for the application and research of scientific researchers in the field of occupational diseases in China.Methods:The information system of scientific and technological achievements was used to search the financial support of the National Natural Science Foundation of China (NSFC) in the field of occupational diseases from 2010 to 2019.Results:From 2010 to 2019, a total of 55 projects were funded under the Occupational Disease code (H2402) , with a total funding of 22.33 million yuan, of which 30 were supported by the Youth Science Foundation, 20 by the Youth Science Foundation and 5 by the Regional Science Foundation. Thirty five items of the research projects focused on pneumoconiosis and other respiratory diseases which accounted for 63.64 per cent. Forty one items of scientific research projects are supported by domestic institutions of higher learning which accounted for 74.55 per cent.Conclusion:The research support of the National Natural Science Foundation of China to the field of occupational diseases (H2402) has increased steadily, but the support of different research directions and supporting units is not balanced. It is suggested that departments concerned strengthen guidance and support for the applicants in less developed areas and weak research directions of the projects in the National Natural Science Foundation.

Objective:To understand the situation supported by the National Natural Science Foundation in the field of occupational diseases (H2402) in China, so as to provide a reference basis for the application and research of scientific researchers in the field of occupational diseases in China.Methods:The information system of scientific and technological achievements was used to search the financial support of the National Natural Science Foundation of China (NSFC) in the field of occupational diseases from 2010 to 2019.Results:From 2010 to 2019, a total of 55 projects were funded under the Occupational Disease code (H2402) , with a total funding of 22.33 million yuan, of which 30 were supported by the Youth Science Foundation, 20 by the Youth Science Foundation and 5 by the Regional Science Foundation. Thirty five items of the research projects focused on pneumoconiosis and other respiratory diseases which accounted for 63.64 per cent. Forty one items of scientific research projects are supported by domestic institutions of higher learning which accounted for 74.55 per cent.Conclusion:The research support of the National Natural Science Foundation of China to the field of occupational diseases (H2402) has increased steadily, but the support of different research directions and supporting units is not balanced. It is suggested that departments concerned strengthen guidance and support for the applicants in less developed areas and weak research directions of the projects in the National Natural Science Foundation.

Objective: To evaluate the feasibility and potential value of comprehensive geriatric assessment (CGA) in elderly (≥60 years) patients with newly diagnosed acute myeloid leukemia (AML) in China. Methods: The CGA results of 83 newly diagnosed AML (non-APL) patients from 16 hospitals in Beijing and Tianjin between March 2016 and December 2017 were prospectively collected and analyzed. The clinical data, treatment and follow-up information were also collected. Results: Of 83 newly diagnosed elderly AML patients, 81 patients (97.6%) completed all designated CGA assessment. The median number of impaired scales of the CGA assessment in the studied population was 2(0-6). Sixteen patients (19.3%) showed no impairments according to the geriatric assessment scales implem ented by this study. The distributions of impaired scales were as follows: impairment in ADL, 55.4%; IADL impairment, 42.2%; MNA-SF impairment, 48.2%; cognitive impairment, 15.7%; GDS impairment, 31.7%; HCT-CI impairment, 19.5%, respectively. In patients with "good" ECOG (n=46), the proportion of impairment for each CGA scale ranged from 6.5% to 37.0% and 32 patients (68.9%) had at least one impaired CGA scale. Survival analysis showed that the number of impaired scales of the CGA was significantly correlated with median overall survival (P=0.050). Conclusions CGA was a tool with feasibility for the comprehensive evaluation in elderly AML patients in China. Combined with age and ECOG, CGA may be more comprehensive in assessing patients’ physical condition.

Objective To explore the protective effect of erythropoietin(EPO) administrated by intranasal on cerebral ischemia reperfusion in rats with acute cerebral infarction reperfusion.Methods Total of 100 SD rats were divided into model control group,sham operation group,intraperitoneal administration group ([PEPO group),nasal saline group (INNS group) group,and nasal drug delivery group (INEPO group) with 20 in each group.The middle cerebral artery occlusion model of rat was established by thread embolism method and the NSS method was used to evaluate the neural behavior of rats.The expression of EPO in peripheral blood,cerebrospinal fluid and brain regions of rats were detected by Elisa.The vascular endothelial growth factor(VEGF) in brain was detected by immunofluorescence and then the density of newborn blood vessels in the brain was measured.Results Fifteen days after the operation,the NSS score of INEPO group(3.80± 1.61) was significantly lower than that of IPEPO group (11.53±2.11),and the difference was statistically significant(P＜0.01).And the levels of EPO in blood,cerebrospinal fluid and different brain regions of rats in INEPO group were higher than that of INNS group(all P＜0.01).Compared with IPE-PO group,the level of EPO cerebrospinal fluid and different brain regions of rats in INEPO group increased obviously,the difference was statistically significant (all P＜0.01),and the EPO concentration of the olfactory bulb was the most obvious (INEPO group:(1 456.90 ± 128.22) pg/ml,IPEPO group:(426.11 ± 36.68)pg/ml,P＜0.01).Seventy-two hours after operation,the expression of CD31 in ischemic penumbra of rats of model control group (18.21 ± 3.45),INNS group (18.54 ± 2.58),IPEPO group (27.01 ± 2.13) and INEPO group(35.52±2.79)was increased compared with sham operation group (5.14± 1.28),and the difference was statistically significant (all P＜0.05).The expression of CD31 in IPEPO group and INEPO group was significantly higher than that in INNS group (P＜0.05).In INEPO group,the expression of CD31 increased significantly compared with that of IPEPO group (P＜0.05).Conclusion Nasal administration of EPO can effectively improve the neurological function of rats with ischemia-reperfusion,and increase the expression of CD31 in the brain tissue of rats.The effect of nasal administration is better than that of intraperitoneal administration.

Objective To explore the effect of the flipped classroom model on the training of nursing theory and skills to newly-contracted nurses. Methods A total of 122 newly-contracted nurses in 2013 were selected as the control group, where the traditional training methods were adopted. The 303 newly-contracted nurses recruited into the hospital in 2014 were set as the experimental group, where the training was carried out by using the flipped classroom model for 1 year. After training, the differences between the two groups in the theoretical test and nursing skills assessment were compared. A satisfaction survey about the flipped classroom model was made in the experimental group. Results Both the scores on the nursing theory and skills in the experimental group were higher than those in the control group (all P<0.001).More than 88.9％of the newly-contracted nurses in the experimental group was for the training arrangement, classroom experience and application of the flipped class model. Conclusion The application of the flipped classroom model in the training of nursing for newly-contracted nurses can improve the learning effect of newly-contracted nurses and enhance their nursing theory and skills.

Objective To evaluate therapeutic effects of metformin on the expression of serum cytokines,balance of splenic Th17/regulatory T cells (Treg) and expression of splenic AMPK-mTOR in collagen-induced arthritis (CIA) rats,and the mechanism thereof.Methods The rat model of CIA was established by injecting bovine type Ⅱ collagen.Forty rats were randomly divided into five groups:the CIA model group(sterile water by gavage),Met-30 mg/kg group (metformin 30 mg ·kg-1 ·d-1 by gavage),Met100 mg/kg group(metformin 100 mg ·kg-1 ·d-1 by gavage),Met-300 mg/kg group(metformin 300 mg ·kg-1 ·d-1 by gavage) and control group (sterile water by gavage).The hind paw volume was recorded once a week.The serum level of cytokines,tumor necrosis factor (TNF)-α,interleukin (IL)-1β,IL-6,and IL-17,were measured by enzyme linked immunosorbent assay (ELISA) 35 days after the initial immunization.The quantity of Th17 and Treg cells were examined by flow cytometry.The expression of AMPK,p-AMPK,mTOR and p-mTOR were examined by western blotting.One-way analysis of variance was used to evaluate the experimental data.Results The values of hind paw volume were decreased on the 35 d of the initial immunization in the Met100 mg/kg [(2.43±0.37) ml,t=2.97,P＜0.05] and Met-300 mg/kg groups [(2.58±0.21) ml,t=2.96,P＜0.05] than those of CIA model group (2.97±0.23) ml.The serum levels of TNF-α,IL-1β,IL-6 and IL-17 on the 35-d after the initial immunization were significantly lower in the metformin therapeutic groups [Met-300 mg/kg group TNF-α (104±8) pg/ml,t=42.77,P＜0.05;IL-1β (183±24) pg/ml,t=60.457,P＜0.05;IL-6 (19.3±2.8) pg/ml,t=53.62,P＜0.05;IL-17 (64.5±6.7) pg/ml,t=47.92,P＜0.05] than those of the CIA model group [TNF-α (246±8) pg/ml;IL-1β (1 336±40) pg/ml;IL-6 (87.0±5.1) pg/ml;IL-17 (282.3±6.8) pg/ml].The quantity of Th17 and Treg cells were significantly different in the Met-300 mg/kg group than those of the CIA model group 35 d after the initial immunization [Th17(6.57±0.39) vs (9.89±0.53),t=8.74,P＜0.05;Treg (7.60±0.45) vs (3.94±0.61),t =8.37,P＜0.05].The expression of p-AMPK on the 35 d after the initial immunization in the metformin therapeutic groups was significantly higher than in the CIA model group(P＜0.05),and the expression of p-mTOR was significantly lower (P＜0.05).Conclusion Metformin can significantly inhibit the serum levels of TNF-α,IL-1β,IL-6 and IL-17 in CIA model rats,and regulate the balance of Th17/Treg through AMPK-mTOR signaling pathway.