Catheter ablation versus medical therapy for atrial fibrillation with prior stroke history: a prospective propensity score-matched cohort study / 老年心脏病学杂志（英文版）

BACKGROUND@#Patients with atrial fibrillation (AF) and prior stroke history have a high risk of cardiovascular events despite anticoagulation therapy. It is unclear whether catheter ablation (CA) has further benefits in these patients.@*METHODS@#AF patients with a previous history of stroke or systemic embolism (SE) from the prospective Chinese Atrial Fibrillation Registry study between August 2011 and December 2020 were included in the analysis. Patients were matched in a 1:1 ratio to CA or medical treatment (MT) based on propensity score. The primary outcome was a composite of all-cause death or ischemic stroke (IS)/SE.@*RESULTS@#During a total of 4.1 ± 2.3 years of follow-up, the primary outcome occurred in 111 patients in the CA group (3.3 per 100 person-years) and in 229 patients in the MT group (5.7 per 100 person-years). The CA group had a lower risk of the primary outcome compared to the MT group [hazard ratio (HR) = 0.59, 95% CI: 0.47-0.74, P < 0.001]. There was a significant decreasing risk of all-cause mortality (HR = 0.43, 95% CI: 0.31-0.61, P < 0.001), IS/SE (HR = 0.73, 95% CI: 0.54-0.97, P = 0.033), cardiovascular mortality (HR = 0.32, 95% CI: 0.19-0.54, P < 0.001) and AF recurrence (HR = 0.33, 95% CI: 0.30-0.37, P < 0.001) in the CA group compared to that in the MT group. Sensitivity analysis generated consistent results when adjusting for time-dependent usage of anticoagulants.@*CONCLUSIONS@#In AF patients with a prior stroke history, CA was associated with a lower combined risk of all-cause death or IS/SE. Further clinical trials are warranted to confirm the benefits of CA in these patients.

A new class of potent liver injury protective compounds: Structural elucidation, total synthesis and bioactivity study

A new class of potent liver injury protective compounds, phychetins A-D ( 1- 4) featuring an unique 6/6/5/6/5 pentacyclic framework, were isolated and structurally characterized from a Chinese medicinal plant Phyllanthus franchetianus. Compounds 2- 4 are three pairs of enantiomers that were initially obtained in a racemic manner, and were further separated by chiral HPLC preparation. Compounds 1- 4 were proposed to be originated biosynthetically from a coexisting lignan via an intramolecular Friedel-Crafts reaction as the key step. A bioinspired total synthesis strategy was thus designated, and allowed the effective syntheses of compounds 2- 4 in high yields. Some of compounds exhibited significant anti-inflammatory activities in vitro via suppressing the production of pro-inflammatory cytokine IL-1β. Notably, compound 4, the most active enantiomeric pair in vitro, displayed prominent potent protecting activity against liver injury at a low dose of 3 mg/kg in mice, which could serve as a promising lead for the development of acute liver injury therapeutic agent.

Heartbeat-aware convolutional neural network for R-peak detection of wearable device ECG data / 南方医科大学学报

OBJECTIVE@#To develop a method for R-peak detection of ECG data from wearable devices to allow accurate estimation of the physiological parameters including heart rate and heart rate variability.@*METHODS@#A fully convolutional neural network was applied to predict the R-peak heatmap of ECG data and locate the R-peak positions. The heartbeat-aware (HA) module was introduced to enable the model to learn to predict the heartbeat number and R-peak heatmap simultaneously, thereby improving the capability of the model for extraction of the global context. The R-R interval estimated by the predicted heartbeat number was adopted to calculate the minimum horizontal distance for peak positioning. To achieve real-time R-peak detection on mobile devices, the deep separable convolution was adopted to reduce the number of parameters and the computational complexity of the model.@*RESULTS@#The proposed model was trained only with ECG data from wearable devices. At a tolerance window interval of 150 ms, the proposed method achieved R peak detection sensitivities of 100% for both wearable device ECG dataset and a public dataset (i.e. LUDB), and the true positivity rates exceeded 99.9%. As for the ECG signal of a 10 s duration, the CPU time of the proposed method for R-peak detection was about 23.2 ms.@*CONCLUSION@#The proposed method has good performance for R-peak detection of both wearable device ECG data and routine ECG data and also allows real-time R-peak detection of the ECG data.

Revision of the Physical Courage at Work Scale / 环境与职业医学

Background According to China's Labor Statistics Yearbook 2020, there were 113293 work-related injuries and 25092 work-related deaths in 2019. It is of great significance to enhance the courage quality of high-risk workers for the maintenance of personal health and the effectiveness of organizational work. Objective To revise the Physical Courage at Work Scale (PCWS) for its application in Chinese employees exposed to high-risk workplace. Methods A total of 1280 high-risk workers completed the revised PCWS for Chinese employees. Item analysis and exploratory factor analysis were used to analyze the scale's construction validity. Confirmatory factor analysis was used to verify the results of exploratory factor analysis, Cronbach's α coefficient was used to verify the reliability of the scale, Pearson correlation analysis of the scale with Mental Quality Questionnaire for Armymen (MQQA) and Norton Courage Measure (CM) was used to verify the validity of the revised PCWS, and Pearson correlation analysis was used to determine the discrimination for each factor of the revised PCWS. Results The results of item analysis showed that the correlation coefficients between the scores of all items and the total score of the revised PCWS were greater than 0.4. The exploratory analysis indicated that there were five factors including immediate danger,providing for family, confronting other's aggression, reporting violations, and contributing to society in the revised version. The confirmatory analysis indicated the five-factor model fitted well (minimum fit function Chi-square/degree of freedom, CMIN/DF=4.60; normed fit index, NFI=0.93; comparative fit index, CFI=0.95; incremental fit index, IFI=0.93; standardized root mean square residual, SRMR=0.05; root mean square error of approximation, RMSEA=0.07). The internal consistency coefficient of the revised PCWS was α=0.95. The correlation coefficients of the revised PCWS with MQQA and CM ranged from 0.11 to 0.28 (P<0.01), and the correlation coefficients between factors of the revised scale ranged from 0.35 to 0.72 (P<0.01). Conclusion The revised PCWS has good reliability and validity in Chinese employees.

Regulatory role of circIGF2BP3 in autophagy in photoaged dermal fibroblasts / 中华皮肤科杂志

Objective:To preliminarily investigate the effect of circIGF2BP3 on autophagy in photoaged dermal fibroblasts.Methods:Human dermal fibroblasts were isolated from circumcised foreskin tissues from 6 children in the Department of Urological Surgery, Third Affiliated Hospital of Sun Yat-sen University. An ultraviolet A (UVA) -induced photoaged human dermal fibroblast model (UVA radiation group) was established by repeated UVA radiation at a dose of 10 J/cm 2 for 14 consecutive days, and human dermal fibroblasts receiving no treatment served as control group. The photoaged cell model was verified by β-galactosidase staining, Western blot analysis for determining P21 protein expression, and cell counting kit-8 (CCK8) assay for evaluating cell viability. Moreover, Western blot analysis was performed to determine the protein expression of autophagy-related proteins P62, microtubule-associated protein 1 light chain 3 (LC3) -Ⅰand LC3-Ⅱ in photoaged human dermal fibroblasts, and real-time quantitative RCR (qRT-PCR) to verify the differential expression of circIGF2BP3 between photoaged and normal human dermal fibroblasts. Furthermore, circIGF2BP3 was biologically annotated. Some cultured primary human dermal fibroblasts were divided into 4 groups: empty vector group transfected with an empty vector, UVA + empty vector group transfected with an empty vector followed by repeated UVA radiation, circIGF2BP3 group transfected with a circIGF2BP3-overexpressing lentiviral vector, UVA + circIGF2BP3 group transfected with a circIGF2BP3-overexpressing lentiviral vector followed by repeated UVA radiation. Western blot analysis was performed to determine the expression of autophagy-related proteins. Statistical analysis was carried out by using t test, one-way analysis of variance and least significant difference- t test. Results:Compared with the control group, the UVA radiation group showed significantly increased proportions of β-galactosidase-positive cells (61.33% ± 5.78% vs. 6.37% ± 0.32%, t = 9.49, P < 0.01) and P21 expression (1.25 ± 0.03 vs. 1.00 ± 0.05, t = 4.26, P < 0.05), but significantly decreased cell viability (74.33% ± 3.48% vs. 100%, t = 7.38, P < 0.01). Moreover, the P62 expression and LC3-Ⅱ/Ⅰ ratio were significantly higher in the UVA radiation group than in the control group (both P < 0.05). The relative expression of circIGF2BP3 was 0.72 ± 0.04 in the photoaged human dermal fibroblasts, which was significantly lower than that in the normal human dermal fibroblasts (1.00 ± 0.03, t = 5.46, P < 0.01). The P62 expression and LC3-Ⅱ/Ⅰ ratio were significantly lower in the circIGF2BP3 group (0.60 ± 0.01, 0.71 ± 0.01, respectively) than in the empty vector group (1.00 ± 0.02, 1.00 ± 0.01, t = 16.25, 2.75, P < 0.01, < 0.05, respectively), and lower in the UVA + circIGF2BP3 group (1.05 ± 0.02, 2.04 ± 0.05, respectively) than in the UVA + empty vector group (1.31 ± 0.02, 2.72 ± 0.14, t = 10.493, 6.472, respectively, both P < 0.01) . Conclusion:circIGF2BP3 can regulate autophagy in UVA-induced photoaged dermal fibroblasts, which provides a new potential therapeutic target for the prevention and treatment of skin photoaging.

Application of an autoregressive integrated moving average model in prediction of cardiovascular disease mortality / 上海预防医学

Objective:To use autoregressive integrated moving average （ARIMA） model for predicting the mortality of cardiovascular diseases in residents in Yushui District， Jiangxi Province， and to provide basis for developing the prevention and control strategies as well as to promote the continuous optimization of chronic disease prevention and treatment demonstration area. Methods:Based on the cardiovascular death monitoring data of residents in Yushui District， Jiangxi Province from 2014 to 2018， Econometrics View 9.0 software was used to construct the ARIMA seasonal adjustment model to predict the monthly cardiovascular death in this area. Results:The monthly death rate of cardiovascular diseases in Yushui showed a long-term rising trend， with an apparent seasonal pattern （a peak of cardiovascular death from December to January each year）. After the original sequence was subjected to first-order difference and first-order seasonal difference， the difference sequence showed good stationarity （P<0.05）. All the theoretical models were listed and their model parameters were calculated respectively. After statistical test （P<0.05）， 7 alternative models for seasonal adjustment of ARIMA were selected. Among them， ARIMA（1，1，1）（1，1，1）12 is the optimal model selected in this study （R2=0.749， Adjustment R2=0.724， AIC=8.454， SC=8.633， HQ=8.515）.And its residual sequence was tested by white noise test （P>0.05）， indicating that the prediction effect was good. Conclusion:ARIMA（1，1，1）（1，1，1） 12 model can accurately simulate the long-term trend and seasonal pattern of cardiovascular disease death in Yushui， and make a scientific prediction of the trend and monthly distribution of cardiovascular disease death in the next three years.

Novel Point Mutation of EBSS Gene Coexisted with 1p36 Deletion

EBSS (epidermolysis bullosa simplex superficialis) is mainly caused by gene mutations which targeted protein as plakophilin-1, desmoplakin and keratins. 1p36 gene deleted could cause typical clinical manifestations and might also affect the expression of functional genes in other regions. Here we reported the first case of PKP1 gene and DSP gene mutation coexisted with 1p36 deletion presented as serious EBSS and 1p36 deletion syndromes and identified a new homozygous mutation in the PKP1 gene (chr1:201292246 c.1672 T＞C) and in the DSP gene (chr6:7580346 c.3923C＞T).

Novel Point Mutation of EBSS Gene Coexisted with 1p36 Deletion

EBSS (epidermolysis bullosa simplex superficialis) is mainly caused by gene mutations which targeted protein as plakophilin-1, desmoplakin and keratins. 1p36 gene deleted could cause typical clinical manifestations and might also affect the expression of functional genes in other regions. Here we reported the first case of PKP1 gene and DSP gene mutation coexisted with 1p36 deletion presented as serious EBSS and 1p36 deletion syndromes and identified a new homozygous mutation in the PKP1 gene (chr1:201292246 c.1672 T＞C) and in the DSP gene (chr6:7580346 c.3923C＞T).

Biosynthesis of lipase by Burkholderia cenocepacia ST8 using waste cooking oil as feedstock

Aims@#Every year, an estimated 25 million tons of waste oil are produced worldwide, and the generation of waste oil is one of the biggest global environmental problems. The incorporation of oil as a substrate for lipase production has been studied and shown to have a positive impact on its production. Burkholderia sp. is one of the major lipase-producing bacteria with their ability in bioremediation of oil-contaminated soil. This study aims to compare the production of lipase by Burkholderia cenocepacia ST8 using waste cooking oil and unused cooking oil as feedstock.@*Methodology and results@#The effect of different types of waste cooking oil (sunflower oil and palm oil) and concentration (1-3%) of waste cooking oil, agitation speed (100-400 rpm) and initial dissolved oxygen concentration (10-50%) on lipase production by B. cenocepacia ST8 under batch fermentation mode were investigated. The major fatty acids of which had been consumed were determined using gas chromatography. Results showed that 2% (v/v) of single used sunflower cooking oil produced the highest lipase activity of 138.86 U/mL with a productivity of 2.10 U/mL/h; agitation speed of 300 rpm produced the highest lipase activity of 183.56 U/mL with a productivity of 3.06 U/mL/h while 30% initial concentration of dissolved oxygen produced a lipase activity of 176.45 U/mL with a productivity of 2.94 U/mL/h. Oleic acid and linoleic acid were found to be the most consumed by B. cenocepacia ST8 among other fatty acids. @*Conclusion, significance and impact of study@#This study shows that 2% (v/v) single used sunflower cooking oil was the better type and optimum concentration of carbon source for the production of lipase by the fermentation of B. cenocepacia under 300 rpm and 30% initial concentration dissolved oxygen. The incorporation of 2% (v/v) single used sunflower cooking oil may be a great alternative to reduce the cost for the production of lipase as well as reducing the amount of waste oil generation.

Feasibility and safety of intracardiac ultrasound-assisted atrial septal puncture during radiofrequency ablation for atrial fibrillation / 中华心血管病杂志

Objective: To explore the feasibility and safety of intracardiac ultrasound-assisted atrial septal puncture (ASP) during radiofrequency ablation for atrial fibrillation. Methods: We enrolled 241 consecutive patients scheduled to radiofrequency ablation for atrial fibrillation in Beijing Anzhen Hospital from July to September 2020. Inclusion criteria: patients aged over 18 years with a clear electrocardiogram record of atrial fibrillation. Patients were divided into 2 groups: ASP with ultrasound-assisted X-ray (ultrasound group, n=123), ASP under X-ray alone (X-ray group, n=118). Clinical features of patients including age, sex, percent of paroxysmal atrial fibrillation, and repeat ablation, CHA2DS2-VASc score and past history (hypertension, diabetes mellitus, coronary artery disease, stroke/transient ischemic attack (TIA), valve diseases) and echocardiographic parameters (left atrial dimension, left ventricular ejection fraction, left ventricular end-diastolic dimension) were obtained and compared. The first-pass rate, radiation exposure time, duration of ASP, and complications of ASP were also compared between the two groups. Results: The age of patients in this cohort was (62.5±8.0) years, and the proportion of males was 57.0% (n=138). Among them, the proportion of paroxysmal atrial fibrillation was 56.0% (n=135), and the ratio of repeat ablation was 17.8% (n=43). Age, sex, percent of paroxysmal atrial fibrillation, history of hypertension, diabetes mellitus were similar between the two groups. The first-pass rate was significantly higher in the ultrasound group than in the X-ray group (94.3% (116/123) vs. 79.7% (94/118), P=0.001); the exposure time of X-ray was significantly shorter in the ultrasound group than in the X-ray group ((31.3±7.9) s vs. (124.8±35.7) s, P<0.001), while the duration of ASP was longer in the ultrasound group ((10.1±1.8) minutes vs. (8.2±1.3) minutes, P<0.001). In terms of complications, the incidence of puncture into the pericardium was lower in the ultrasound group (0 vs.3.4% (4/118), P=0.039); the rate of transient ST-segment elevation post ASP was similar between the ultrasound group and X-ray group (2.4% (3/123) vs. 1.7% (2/118), P=0.999). Conclusion: Intracardiac ultrasound-assisted atrial septal puncture can effectively improve the accuracy of atrial septal puncture, shorten the radiation exposure time, and reduce the complications related to atrial septal puncture.

Explanation and elaboration of the consensus "photoprotection of the future: challenges and opportunities" : international development trends of sunscreen cosmetics and their enlightenment to China / 中华皮肤科杂志

At present, there are still some misunderstandings regarding sunscreen cosmetics. For example, the higher the sun protection factor, the better the sunscreen cosmetics, and sunscreen agents can cause calcium deficiency in users. As far as sunscreen cosmetics are concerned, there are also many problems, concerns and challenges, such as inconsistent testing and labeling methods for sun protection factor, insufficient protection wavelength range, and unclear safety to the human body and environment. This article describes global issues in sunscreen cosmetics, their development trends, and enlightenment to the research and development of sunscreen cosmetics in China, aiming to provide a reference for clinicians.

Effects of Hymagic-4D on sensitive skin: a randomized, parallel, self-controlled clinical study / 中华医学美学美容杂志

Objective:To evaluate the efficacy and safety of Hymagic-4D multi-essence (miniHA, acetylated sodium hyaluronate, sodium hyaluronate, sodium hyaluronate cross-linked polymer) on sensitive skin.Methods:The clinical trial was conducted from April 2, 2019 to April 30, 2019 in the Cosmetic Dermatology Laboratory of the Third Affiliated Hospital of Sun Yat-Sen University. A total of 33 subjects (average age of 43±9.5) completed the trial. Subjects diagnosed as sensitive skin according to the criteria were enrolled. Hymagic-4D were randomly applied on one side of the face while macromolecular hyaluronic acid was applied on opposite side for 28 days. Skin biophysical properties, lactic test, clinical efficacy and safety were evaluated by the investigators at day 0, day 7, day 14 and day 28. Skin water content, TEWL and a*value were measured at the same time.Results:Dates showed that at day 7, day 14 and day 28, the a* values on Hymagy-4D using side were 8.54±3.08, 8.87 ±3.21 and 8.39±3.21, lower than that on the side of control 9.48±3.09, 9.51±3.30 and 9.03±2.95 ( P<0.01); skin roughness score, dryness score and erythema score on hymagy-4d using side were significantly lower than before ( P<0.01), and significantly lower than that on the control side ( P<0.01). Hydration, TEWL, pH value, L value and total score of lactic acid tingling test which were significantly improved on both facial skin compared to the baseline ( P<0.05) showed no statistical difference between two facial sides ( P>0.05) during 28-day treatment. Conclusions:This study demonstrates that Hymagic-4D has more effective in repairing skin barrier and inhibiting skin inflammation than single component hyaluronic acid on sensitive skin persons.

Associations Between Knowledge on Optimal Control of Serum Phosphate, Perceived Social Support, Dietary Phosphorus Intake and Phosphate Compliance Among Hemodialysis Patients

@#Introduction: Hyperphosphatemia is common among hemodialysis patients, often accompanies with unfavourable clinical outcomes. Several factors affect phosphate compliance among hemodialysis patients, with lack of such information at the local context. Thus, this cross-sectional study aimed to determine the associations of sociodemographic factors, knowledge on optimal control of serum phosphate, perceived social support from family, dietary phosphorus intake and phosphate compliance among hemodialysis patients. Methods: Structured questionnaire was used to obtain information on socioeconomic factors, knowledge, family social support and dietary phosphorus intakes of hemodialysis patients, with serum phosphate level was used as the surrogate marker for phosphate compliance. Results: A total of 76 patients (Mean age of 52 years old) were recruited. Hyperphosphatemia was prevalent with approximately 60% of the patients failed to achieve the target. Approximately 90% of the patients perceived low level of family social support. Young patients had significant higher serum phosphate compared to their older counterparts (r = -0.297, p =0.009). Serum phosphate was positively correlated with dietary intake of phosphorus, dialysis vintage (r = 0.301, p = 0.006) and comorbidity score (r = 0.325, p = 0.008) while negatively correlated with dialysis dose (r = -0.582, p = 0.002) and family social support (r = -0.263, p = 0.024). Conclusion: The promising role of dietary phosphorus intake in managing hyperphosphatemia deserves further attention. Innovative approaches are needed to promote self-adherence on serum phosphate especially the younger patients. It is imperative to promote family social support in the management of hyperphosphatemia among hemodialysis patients.

Dementia and the Risk of Hip Fracture

No abstract available.

Exploration and consideration on quantitative indicators of clinical final examination for standardized training of residents in dermatology / 中华医学教育探索杂志

Clinical final examination is an important link in the standardized training of residents in dermatology and quantification of evaluation indicators is one of the important parameters. In this study, the scores of clinical examinations of six candidates who participated in standardized training of residents in dermatology of Sun Yat-Sen University in June 2019 were taken as examples to explore the quantitative indicators of standardized and multi-station clinical final examinations. The indicators contained four stations and five links: skin pathological reading, skin biopsy, medical history collection and physical examination, medical record writing, and comprehensive questioning, which covered the main contents of the standardized training outline of residents in dermatology. Each evaluation indicator was refined and quantified. Finally, heuristic ideas were put forward, including a wider range of standardized and multi-station clinical examinations, introduction of new examination places, and utilization of information technology.

Inflammatory Bowel Disease and the Risk of Herpes Zoster

No abstract available.

Mechanisms underlying repeated ultraviolet A radiation-induced DNA damage in human skin fibroblasts / 中华皮肤科杂志

Objective@#To evaluate the effects of repeated ultraviolet A (UVA) radiation on DNA damage, repair and replication processes in human skin fibroblasts, and to explore their mechanisms.@*Methods@#Fibroblasts were isolated from the circumcised foreskins of 3 children in the Department of Urological Surgery, Third Affiliated Hospital, Sun Yat-sen University, and subjected to a primary culture. Cultured human skin fibroblasts of 3rd-10th passages were divided into 2 groups: UVA group treated with repeated UVA radiation to establish a chronic photodamaged cell model, and control group receiving no treatment. Cell counting kit 8 (CCK-8) assay, β-galactosidase staining and flow cytometry were performed to assess cellular proliferative activity, and determine the proportion of photoaged cells and apoptosis rate respectively. Reverse transcription reaction was performed to establish a differentially expressed cDNA library, which was then subjected to high-throughput sequencing. The cDNA sequencing results were compared between the control group and UVA group, and the differentially expressed genes were analyzed in Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The data were compared between the two groups by using two independent sample t test.@*Results@#Compared with the control group, the UVA group showed significantly decreased cellular proliferative activity (72.0% ± 5.2% vs. 96.0% ± 3.7%, t = 6.51, P < 0.05) , but significantly increased proportion of photoaged cells (79.7% ± 5.2% vs. 6.4% ± 0.8%, t=24.12, P < 0.05) and apoptosis rate (29.0% ± 3.3% vs. 6.0% ± 5.9%, t= 5.89, P < 0.05) . Among the key enzymes involved in DNA mismatch repair, replication and base excision repair processes, the expression of DNA ligase 1 (Lig1) , ribonuclease (RNase) H2A and helicase Dna2 in the UVA group was 0.47 ± 0.13, 0.44 ± 0.07 and 0.49 ± 0.11 times (all P < 0.01) that in the control group respectively. After the UVA-induced chronic photodamage in the human skin fibroblasts, After the UVA-induced chronic photodamage in the human skin fibroblasts, Lig expression decrease could block DNA single-base excision repair, Lig and Lig1 expression decrease could block DNA multiple-base excision repair, Lig1 expression decrease could block DNA mismatch repair, and RNaseH2A, Dna2 and Lig1 expression decrease could block DNA replication.@*Conclusion@#Repeated UVA radiation can change the expression of key enzymes involved in DNA base excision repair, DNA mismatch repair and DNA replication processes in skin fibroblasts, and then affect DNA repair and DNA replication processes in skin fibroblasts.

Cloning and expression of hyaluronan synthase (hasA) in recombinant Escherichia coli BL21 and its hyaluronic acid production in shake flask culture

Aims@#Hyaluronic acid (HA) is a high molecular weight polymer and a major component of mucoid capsule in bacteria and extracellular matrix (ECM) of vertebrate tissue. Due to its unique characteristics, HA is used extensively in medical and cosmetic field. However, because of the exotoxins production from animal tissues extraction and Streptococcus zooepidemicus, HA production by recombinant microorganisms has gained interest. The present study was aimed at cloning of hasA gene in Escherichia coli and optimization of the medium components for HA production. @*Methodology and results@#A fragment of an approximate size of 1.5 kb that encodes the hyaluronan synthase (hasA) gene from S. zooepidemicus ATCC 39920 was amplified by PCR using hasA-specific primers. The hasA gene was ligated into the bacterial expression vector pLbADH and transformed into the expression host, Escherichia coli BL21 strain. Then, genetically engineered E. coli strain BL21 was used for the production of HA by fermentation using different glucose concentration (10-50 g/L) and different IPTG concentration (0.1, 0.5 and 1.0 mM) in shake flask culture. Amongst varying glucose concentrations, results showed that 50 g/L glucose with nutrient rich media containing nitrogen source was able to produce the highest HA concentration (0.115 ± 0.002 g/L). With addition of 1.0 mM IPTG, HA production reached a peak 0.532 ± 0.026 g/L which is around fivefold higher compared to without IPTG. @*Conclusion, significance and impact of study@#The hasA gene was cloned from S. zooepidemicus and successfully expressed in recombinant E. coli BL21 cells. This low molecular weight HA is gaining more importance in medical and cosmetic application due to possess pronounced free radical scavenging and antioxidant activities.

Implementation of standardized teaching rounds in clinical probation sessions of Dermatology and Venereology centered on rash / 中华医学教育探索杂志

Taking the course's characteristics and advantages into account, this study explores the systematic implementation of standardized teaching rounds in the clinical probation sessions of the Dermatology and Venereology course , and evaluates its effect by analyzing the cases of 125 medical students from grade 2015 of Sun Yat-sen University . The results showed that the implementation of standardized teaching rounds has positive effect on the course.

Probation teaching practice focusing on ward teaching for dermatology and venereology / 中华医学教育探索杂志

A total of 105 undergraduate students of the class 2014 majoring in clinical medicine in Sun Yat-Sen University received probation teaching in our department from October 2017 to May 2018,according to the syllabus of dermatology and venereology of clinical medicine.Senior teachers in our department were responsible for probation teaching,with the help of the independent wards in our department and probation teaching at the outpatient service.The teachers recorded the whole teaching process and evaluated the students' memory after probation.Through the teaching in wards and at the outpatient service,the students mastered the requirements in the syllabus of dermatology and venereology and achieved good results.