Evaluation of the Effect of Parental Participation on Chinese Adolescent Behavioral Development Through the Mediating Effect of Peers: A Moderated Mediation Model.

Background: With the rapid changes in the social environment, adolescents are facing increasing academic pressure and challenges to their physical and mental development in the socialization process. The purpose of this study was to investigate the influence mechanisms of parental participation on adolescent behavioral development (learning persistence, expressive language ability and knowledge absorption ability), revealing the mediation role of adolescent positive and negative peer interactions between parental participation and behavioral development, and whether differences in parents and children's educational expectations moderate this process. Methods: This study was measured using the Parental Participation Questionnaire, Peer Interaction Questionnaire, Behavioral Development Scale, and Educational Expectancy Gap from the China Education Panel Survey. A total of 7730 seventh-grade students and their parents were invited to participate, to establish a moderated mediation model, and the significance of the mediation effect was tested using the bias-corrected percentile Bootstrap method. Results: (1) High frequent parental participation has a significant positive effect on adolescent behavioral development, including behavioral participation, emotional participation, and educational participation all exerting varying degrees of positive influence, as well as positively influencing adolescents' peer interactions. (2) Positive and negative peer interactions play the mediation role of 12.3% and 2.5% respectively in the process of parental participation affecting adolescent behavioral development. (3) Comparing "educational expectation gap - equal", the "educational expectation gap - high" negatively moderates the effect of parental participation on adolescent behavioral development and positive peer interaction (inhibitory effect), the "educational expectation gap - low" positively moderates the effect of parental participation on negative peer interaction (facilitation effect), which meant that the "educational expectation gap - equal" between parents and children is a more desirable state. Conclusion: These findings provide empirical support and effective operational suggestions to further promote positive adolescent behavioral development. Particularly for developing countries, it is recognized that positive parental participation and peer interaction, as well as equal educational expectation of parents and children, are protective factors for adolescent development.

Artificial intelligence promotes shared decision-making through recommending tests to febrile pediatric outpatients.

BACKGROUND: To promote the shared decision-making (SDM) between patients and doctors in pediatric outpatient departments, this study was designed to validate artificial intelligence (AI) -initiated medical tests for children with fever. METHODS: We designed an AI model, named Xiaoyi, to suggest necessary tests for a febrile child before visiting a pediatric outpatient clinic. We calculated the sensitivity, specificity, and F1 score to evaluate the efficacy of Xiaoyi's recommendations. The patients were divided into the rejection and acceptance groups. Then we analyzed the rejected examination items in order to obtain the corresponding reasons. RESULTS: We recruited a total of 11,867 children with fever who had used Xiaoyi in outpatient clinics. The recommended examinations given by Xiaoyi for 10,636 (89.6%) patients were qualified. The average F1 score reached 0.94. A total of 58.4% of the patients accepted Xiaoyi's suggestions (acceptance group), and 41.6% refused (rejection group). Imaging examinations were rejected by most patients (46.7%). The tests being time-consuming were rejected by 2,133 patients (43.2%), including rejecting pathogen studies in 1,347 patients (68.5%) and image studies in 732 patients (31.8%). The difficulty of sampling was the main reason for rejecting routine tests (41.9%). CONCLUSION: Our model has high accuracy and acceptability in recommending medical tests to febrile pediatric patients, and is worth promoting in facilitating SDM.

Impacts of family environment on adolescents' academic achievement: The role of peer interaction quality and educational expectation gap.

The current study uses a two-wave longitudinal survey to explores the influence mechanism of the family environment on adolescents' academic achievement. The family environment is measured by parents and children's reports, including family atmosphere, parent-child interaction, and family rules, to reveal the mediating effect of adolescents' positive or negative peers between the family environment and academic achievement, and whether the gap between self- and parental educational expectation plays a moderating effect. This study uses the data of the China Education Panel Study (CEPS); the survey samples include 9,449 eighth-grade students (Mage = 13.55 years, SD = 0.70), establishing a multilevel moderated mediating effect model. The results showed (1) the family environment and peer interaction quality can positively predict adolescents' academic achievement. (2) Using the KHB test, peer interaction quality plays a partial mediating role in the process of family environment positively affecting academic achievement, and the mediating ratio is 27.5%. (3) The educational expectation gap moderates the effect of the family environment on academic achievement and also on peer interaction quality. Therefore, from the perspective of environment and important others, to correctly grasp the academic achievement of junior high school students in the process of socialization, it is necessary to recognize that the family environment, peer interaction quality, and educational expectation gap play an important role.

Time-course transcriptome profiling revealed the specific expression patterns of MADS-box genes associated with the distinct developmental processes between winter and spring wheat.

The shoot apex is a region where new cells are produced and elongate. The developmental state of the wheat shoot apex under low temperature affects its cold resistance. In this study, the morphology of shoot apex before overwintering was characterized for 24 wheat line with different winter and spring characteristics. Our research showed that the shoot apex of autumn-sown spring wheat lines reached the temperature sensitive double-ridge stage before overwintering, whereas shoot apex of winter wheat lines are found in temperature-insensitive vegetative or elongation stages. In order to explore how gene expression is associated with shoot apex differentiation in winter and spring wheat, we used strand-specific RNA sequencing to profile the gene expression patterns at four time-points between 14 after germination and 45 days after germination in the winter wheat cultivar Dongnongdongmai No. 1 (DM1) and in the spring wheat cultivar China Spring (CS). We identified 11,848 differentially expressed genes between the two cultivars. Most up-regulated genes in CS were involved in energy metabolism and transport during the seedling stage, whereas up-regulated genes in DM1 were involved in protein and DNA synthesis. MADS-box genes affect plant growth and development. In this study, MADS-boxes with differential expression between CS and DM1 were screened and evolutionary tree analysis was conducted. During all sampling periods, CS highly expressed MADS-box genes that induce flowering promotion genes such as VRN1, VRT and AG, while lowly expressed MADS-box genes that induce flowering-inhibiting homologous genes such as SVP. TaVRN1 composition in DM1 and CS was vrn-A1, vrn-B1, and Vrn-D1b. Analysis of the sequence of TaVRN1 (TraesCS5A01G391700) from DM1 and CS revealed 5 SNP differences in the promoter regions and 3 SNP deletions in the intron regions. The expression levels of cold resistant genes in DM1 were significantly higher than those in CS at seedling stage (neither DM1 nor CS experienced cold in this study), including CBF, cold induced protein,acid desaturase and proline rich proteins. Additionally, the expression levels of auxin-related genes were significantly higher in CS than those in DM1 at 45 days after germination. Our study identified candidate genes associated with the process of differentiation of the shoot apex in winter and spring wheat at the seedling stage and also raised an internal stress tolerance model for winter wheat to endogenously anticipate the coming stressful conditions in winter.

Pre-Consultation System Based on the Artificial Intelligence Has a Better Diagnostic Performance Than the Physicians in the Outpatient Department of Pediatrics.

Artificial intelligence (AI) has been deeply applied in the medical field and has shown broad application prospects. Pre-consultation system is an important supplement to the traditional face-to-face consultation. The combination of the AI and the pre-consultation system can help to raise the efficiency of the clinical work. However, it is still challenging for the AI to analyze and process the complicated electronic health record (EHR) data. Our pre-consultation system uses an automated natural language processing (NLP) system to communicate with the patients through the mobile terminals, applying the deep learning (DL) techniques to extract the symptomatic information, and finally outputs the structured electronic medical records. From November 2019 to May 2020, a total of 2,648 pediatric patients used our model to provide their medical history and get the primary diagnosis before visiting the physicians in the outpatient department of the Shanghai Children's Medical Center. Our task is to evaluate the ability of the AI and doctors to obtain the primary diagnosis and to analyze the effect of the consistency between the medical history described by our model and the physicians on the diagnostic performance. The results showed that if we do not consider whether the medical history recorded by the AI and doctors was consistent or not, our model performed worse compared to the physicians and had a lower average F1 score (0.825 vs. 0.912). However, when the chief complaint or the history of present illness described by the AI and doctors was consistent, our model had a higher average F1 score and was closer to the doctors. Finally, when the AI had the same diagnostic conditions with doctors, our model achieved a higher average F1 score (0.931) compared to the physicians (0.92). This study demonstrated that our model could obtain a more structured medical history and had a good diagnostic logic, which would help to improve the diagnostic accuracy of the outpatient doctors and reduce the misdiagnosis and missed diagnosis. But, our model still needs a good deal of training to obtain more accurate symptomatic information.

Real-World Verification of Artificial Intelligence Algorithm-Assisted Auscultation of Breath Sounds in Children.

Objective: Lung auscultation plays an important role in the diagnosis of pulmonary diseases in children. The objective of this study was to evaluate the use of an artificial intelligence (AI) algorithm for the detection of breath sounds in a real clinical environment among children with pulmonary diseases. Method: The auscultations of breath sounds were collected in the respiratory department of Shanghai Children's Medical Center (SCMC) by using an electronic stethoscope. The discrimination results for all chest locations with respect to a gold standard (GS) established by 2 experienced pediatric pulmonologists from SCMC and 6 general pediatricians were recorded. The accuracy, sensitivity, specificity, precision, and F1-score of the AI algorithm and general pediatricians with respect to the GS were evaluated. Meanwhile, the performance of the AI algorithm for different patient ages and recording locations was evaluated. Result: A total of 112 hospitalized children with pulmonary diseases were recruited for the study from May to December 2019. A total of 672 breath sounds were collected, and 627 (93.3%) breath sounds, including 159 crackles (23.1%), 264 wheeze (38.4%), and 264 normal breath sounds (38.4%), were fully analyzed by the AI algorithm. The accuracy of the detection of adventitious breath sounds by the AI algorithm and general pediatricians with respect to the GS were 77.7% and 59.9% (p < 0.001), respectively. The sensitivity, specificity, and F1-score in the detection of crackles and wheeze from the AI algorithm were higher than those from the general pediatricians (crackles 81.1 vs. 47.8%, 94.1 vs. 77.1%, and 80.9 vs. 42.74%, respectively; wheeze 86.4 vs. 82.2%, 83.0 vs. 72.1%, and 80.9 vs. 72.5%, respectively; p < 0.001). Performance varied according to the age of the patient, with patients younger than 12 months yielding the highest accuracy (81.3%, p < 0.001) among the age groups. Conclusion: In a real clinical environment, children's breath sounds were collected and transmitted remotely by an electronic stethoscope; these breath sounds could be recognized by both pediatricians and an AI algorithm. The ability of the AI algorithm to analyze adventitious breath sounds was better than that of the general pediatricians.

Management in the paediatric wards facing novel coronavirus infection: a rapid review of guidelines and consensuses.

OBJECTIVES: Relevant guidelines and consensuses for COVID-19 contain recommendations aimed at optimising the management in paediatric wards. The goal of this study was to determine the quality of those recommendations and provide suggestions to hospital managers for the adjustment of existing hospital prevention and control strategies, and also to offer recommendations for further research. DESIGN: A rapid review of the guidelines and consensuses for the management in paediatric wards facing COVID-19. METHODS: PubMed, EMBASE, the Cochrane Library, UpToDate, China National Knowledge Infrastructure, the Wanfang database and relevant websites such as medlive.cn, dxy.cn, the National Health and Health Commission and the China Center for Disease Control and Prevention were systematically searched through late May 2020. The Appraisal of Guidelines for Research and Evaluation II (AGREE II) tool was then used to assess the quality of the selected articles and summarise the relevant evidence concerning management in paediatric wards. RESULTS: A total of 35 articles were included, composed of 3 consensus guidelines, 25 expert consensuses and 7 expert opinions. Of the 35 papers, 24 were from China, 2 from the USA, 1 from Spain, 1 from Brazil, 1 from Saudi Arabia and 6 from multinational cooperative studies. Scores for the six domains of the AGREE II tool (scope and purpose, stakeholder involvement, rigour of development, clarity of presentation, applicability and editorial independence) were 98.57%, 53.57%, 17.92%, 69.62%, 26.96% and 50.35%, respectively. Recommendations for nosocomial infection and control, human resource management as well as management of paediatric patients and their families were summarised. CONCLUSIONS: Due to the outbreak of COVID-19, the quality of rapid guidelines and consensuses for the management in paediatric wards affected by COVID-19 is unsatisfactory. In the future, it will be necessary to develop more high-quality guidelines or consensuses for the management in paediatric wards to deal with nosocomial outbreaks in order to fully prepare for emergency medical and health problems.

Serum calcium level is associated with brachial-ankle pulse wave velocity in middle-aged and elderly Chinese.

OBJECTIVE: To study the relation between serum calcium level and elevated BaPWV in Chinese subjects. METHODS: The relation between serum calcium level and elevated BaPWV was studied in 9 615 subjects. The mean value of left and right BaPWV was analyzed. BaPWV was defined as high when it was ⋝1752.5 cm/s (the upper quartile) either side. RESULTS: The BaPWV and its elevated percentage progressively increased across the quartiles of the serum calcium level (P<0.05). The prevalence of elevated BaPWV was significantly higher in subjects of the second, third and highest quartiles than in those of the lowest quartile (26.9%, 28.4%, and 33.2% vs 23.7%, P=0.0116, P=0.0004, and P<0.0001). Logistic regression analysis revealed that the risk of elevated BaPWV was 1.32- fold higher in subjects of the highest quartile than in those of the lowest quartile (OR=1.32, 95% CI: 1.08-1.60). CONCLUSION: The elevated serum calcium level is related to an elevated BaPWV and a higher risk of arterial stiffness, independent of conventional risk factors, in middle-aged and elderly Chinese subjects.

[The analysis of the sampling modulation transfer function and the influence on the Gaussian spectra].

As the parameters of the photoelectric detector have important effects on the performance of the dispersive spectrometers, it is necessary to detail the discrete sampling process of the photoelectric detector array. In the present paper, the sampling model was setup, and the effects on the sampling results caused by the spatial frequency of the cosine signal, the width of the sampling pixel, and the initial phase of the sampling pixel position to the crest of the input cosine signal were discussed thoroughly in the frequency domain. By introducing the integral function, a general expression of the sampling modulation transfer function was given, and the concept and expression of the average sampling modulation transfer function was proposed. Since that expression eliminates the effect of initial phase, it is much more convenient to the practical applications. For the typical Gaussian spectrum produced by the dispersive spectrometer, the Fourier transform result of that spectrum was multiplied by the average sampling modulation transfer function to produce a functional expression of the modulation transfer function of the whole system. The average aliasing error of the sampling process was expressed as a function of spatial frequencies; the relationship between the peak value of the average aliasing error and the width of the Gaussian spectrum was discussed; and the critical value of the spectrum width to restore this spectrum precisely was proposed. That critical value is significant for providing guidance to the design and fabrication of dispersive spectrometers.

A high-yield and scaleable adenovirus vector production process based on high density perfusion culture of HEK 293 cells as suspended aggregates.

Cells of the human embryonic kidney cell line (HEK 293) were grown as suspended aggregates in stirred vessels and infected with a recombinant adenovirus vector (Ad-TH-GFP). Regular spherical aggregates with the mean diameter less than 300 microm and a viable cell density greater than 5 x 10(6) cells x ml(-1) were readily achieved after 9 day culture in spinner flasks. The HEK 293 cells growing as suspended aggregates could be efficiently infected by Ad-TH-GFP at an MOI of 10 with a prolonging infection time up to 144 hour post-infection (hpi). The time profile of Ad-TH-GFP production was strongly corresponding to the infection process with a virus concentration peak occurred consistently at 144 h after infection. And the infected aggregates essentially maintained spherical in shape, the portion of dissociated cells from the infected aggregates was less than 5% at 144 hpi. Perfusion culture of HEK 293 cells grown as suspended aggregates in a 7.5 L stirred tank bioreactor and infected with Ad-TH-GFP at a density higher than 1 x 10(7) cells x ml(-1) resulted in a similar Ad-TH-GFP production kinetics, but a much higher virus yield approximately at 5.7 x 10(11) GTU ml(-1) at 144 hpi to that of the infected spinner flask cultures. These results demonstrate the feasibility for using suspended cell aggregates as an immobilization system to facilitate perfusion in stirred tank bioreactors, and improve volumetric productivities by eliminating the cell density effect.

A 2-way cross-over, open-labeled trial to compare efficacy and safety of insulin Aspart and Novolin R delivered with CSII in 21 Chinese diabetic patients.

BACKGROUND: Subcutaneous absorption is accelerated by the monomeric conformation of insulin Aspart, which provides good glycemic control with a lower risk of hypoglycemia and less body weight increase. In the present study we investigated the efficacy and safety of a rapid-acting human insulin analogue (insulin Aspart) delivered with continuous subcutaneous insulin infusion (CSII) into Chinese diabetic patients. METHODS: A total of 21 patients with type 1 or type 2 diabetes were recruited for the 2-way cross-over, open-labeled trial, and then randomized to Group A (n = 10, treated with insulin Aspart) or Group B (n = 11, treated with Novolin R). Insulin Aspart and Novolin R were administered by CSII. Capillary glucose concentrations were measured at 8 time points, pre-prandial and postprandial, bedtime (10 pm), midnight (2 am) every day during the treatment. RESULTS: The average capillary glucose profiles for the day were much better controlled in Group A than in Group B (P < 0.01). The blood glucose levels were particularly better controlled in Group A than in Group B at pre-breakfast ((6.72 +/- 1.24) mmol/L vs (7.84 +/- 1.58) mmol/L, P = 0.014), post-breakfast ((8.96 +/- 2.41) mmol/L vs (11.70 +/- 3.11) mmol/L, P = 0.0028), post-supper ((8.15 +/- 2.10) mmol/L vs (10.07 +/- 2.36) mmol/L, P = 0.008), bed time ((7.73 +/- 1.72) mmol/L vs (9.39 +/- 2.05) mmol/L, P = 0.007) and midnight ((6.32 +/- 1.16) mmol/L vs (7.48 +/- 1.36) mmol/L, P = 0.0049). There was no significant difference in the frequency of hypoglycemic episodes between the two groups. CONCLUSION: Insulin Aspart results in better control of blood glucose levels than regular human insulin (Novolin R) in diabetic patients during delivery by CSII.

[Enhancement of exogenous gene expression by artificial transcription factor in CHO cells].

Using the amino acids 1-147 of the yeast transcriptional activator GAL4 as the DNA-binding domain and four tandem repeats of the 12-aa peptide (DALDDFDLDMLG) of the herpesvirus as the activation domain, an artificial transcription factor, GVP4,was constructed via the linkage of the nuclear localization signal sequence of SV40. And then, GVP4 was cloned into expression vector pcDNA3 . 1/Hygro ( + ) . Various amounts of targeting sites of artificial transcription factor were linked to the upstream of promoter CMV in exogenous gene expression vector pcDNA3.1 ( + ) that separately harbored EGFP cDNA and t-PA cDNA.The CHO cells were then co-transfected with GVP4 expression vector and EGFP or t-PA expression vector. The effect of GVP4 on exogenous gene expression was evaluated by measuring the fluorescence intensity of EGFP in CHO cells and the concentration of t-PA in the supernatant. GVP4 showed positive effect on the enhancement of exogenous gene expression in CHO cells integrated with targeting sites of artificial transcription factor. And, CHO cells integrated with 10 targeting sites of GVP4 was more favorable to foreign gene expression, which resulted in 2-3-fold increase in both EGFP and t-PA expressions. These results indicated that artificial transcription factor is potent in the enhancement of exogenous gene expression in mammalian cells.

Enhancement of exogenous gene expression by artificial transcription factor in CHO cells / 生物工程学报

Using the amino acids 1-147 of the yeast transcriptional activator GAL4 as the DNA-binding domain and four tandem repeats of the 12-aa peptide (DALDDFDLDMLG) of the herpesvirus as the activation domain, an artificial transcription factor, GVP4,was constructed via the linkage of the nuclear localization signal sequence of SV40. And then, GVP4 was cloned into expression vector pcDNA3 . 1/Hygro ( + ) . Various amounts of targeting sites of artificial transcription factor were linked to the upstream of promoter CMV in exogenous gene expression vector pcDNA3.1 ( + ) that separately harbored EGFP cDNA and t-PA cDNA.The CHO cells were then co-transfected with GVP4 expression vector and EGFP or t-PA expression vector. The effect of GVP4 on exogenous gene expression was evaluated by measuring the fluorescence intensity of EGFP in CHO cells and the concentration of t-PA in the supernatant. GVP4 showed positive effect on the enhancement of exogenous gene expression in CHO cells integrated with targeting sites of artificial transcription factor. And, CHO cells integrated with 10 targeting sites of GVP4 was more favorable to foreign gene expression, which resulted in 2-3-fold increase in both EGFP and t-PA expressions. These results indicated that artificial transcription factor is potent in the enhancement of exogenous gene expression in mammalian cells.

Cultivation of recombinant Chinese hamster ovary cells grown as suspended aggregates in stirred vessels.

Recombinant Chinese hamster ovary (rCHO) cells capable of producing a prourokinase mutant (mPro-uk) grown as suspended aggregates in stirred vessels were described and characterized. The addition of chitosan to a mixture of DMEM and Ham's F12 (D-MEM/F-12) medium promoted cell aggregation and spheroid formation efficiently. Multicellular aggregates formed immediately after the rCHO cells were inoculated into the chitosan-added medium, and the mean diameter of the cell aggregates reflecting the aggregate size increased with culture time, shifting from 65 to 163 mum after 2 and 9 d of culture in spinner flasks. No significant difference in the metabolism performance of the rCHO cells was observed between suspended aggregates and anchored monolayers. However, the cells cultured as suspended aggregates showed a marked decrease in growth rate as evaluated from specific growth rate (mu). Replacing D-MEM/F-12 medium with CD 293 medium caused compact spherical cell aggregates to dissociate into small irregular aggregates and single cells without apparent effects on cell performance in subcultures. The perfusion culture of the rCHO cells grown as suspended aggregates in a 2-l stirred tank bioreactor for 15 d resulted in a maximum viable cell density of 5.6 x 10(6) cells ml(-1) and an mPro-uk concentration of about 2.6 x 10(3) IU ml(-1), and cell viability was remained at roughly 90% during the entire run.

[In vitro cytolysis of B-lymphoma cells mediated by an anti-CD3/anti-CD20 bispecific single-chain antibody].

After having successfully constructed and expressed the gene of the anti-CD3/anti-CD20 bispecific single-chain antibody (bscCD3 x CD20), here we analyzed its in vitro bioactivity of mediating the lysis of Ramous human B-lymphoma cells in the presence of T-enriched human peripheral blood lymphocytes (PBL). Obvious opoptosis characters were observed by Annexin V/PI(AV/PI) stained and scanning electron microscope. As evaluated by non-radioactive cytotoxity assay, the bscCD3 x CD20 showed potent bioactivity of mediating human B-lymphoma cells lysis in the presence of T-enriched human PBL. The potency of cytotoxicity depended on the ratios of effect cells to target cells (E:T) used. Further, the antibody showed a dose and time-dependent effect on mediating Ramous cells lysis. The specific lysis reached about 87.3% at an antibody concentration of 5microg/mL and E:T used at 10:1. Clear changes in apoptogenes expression profiles were detected by apoptosis gene array after Ramous cells were treated with the antibody and PBL. Among the upregulated apoptogenes, ATM and P53 showed an increase of 187 times and 15 times respectively, which suggested that ATM-p53 pathway may be the main apoptosis way of Ramous cells induced by T cells in the presence of the bscCD3 x CD20.

[Effects of hydrodynamic on aggregates formation, growth and metabolism of HEK293 cells in suspension culture].

By using the size distribution of cell aggregates, viable cell density, cell viability, specific consumption rate of glucose (q(glc)), specific production rate of lactate (q(lac)) and lactate transform rate (Y(lac/glc)) as the evaluation indexes, the effects of hydrodynamic on aggregates formation, growth and metabolism of HEK293 cells in suspension culture were examined in 250mL spinner-flasks by setting the agitation rates at 25, 50, 75 and 100r/min, respectively. It was found that agitation plays an important role in HEK293 cell aggregates formation and cell aggregates size distribution. After 7d cultivation in spinner-flasks operated at 50r/min and 75r/min, the average diameter of HEK293 cell aggregates was 201 microm and 175 microm, respectively, with the fraction of aggregates larger than 225 microm less than 10%. The cell viability was kept above 90% with the metabolic indexes, including q(glc), q(lac) and Y(lac/glc) kept constant. These results demonstrated that hydrodynamic derived from the proper agitation play a decisive role in controlling the formation and size distribution of HEK293 cell aggregates, and provided sufficient mass transfer to support the normal growth and metabolism of HEK293 cells in suspended aggregates.

Characteristics of HEK293 Cells Growth and Metabolism under Carrier-free Immobilization Culture Mode / 中国生物工程杂志

By using the cell density, cell viability, size distribution of cell aggregates,specific consumption rate of glucose (q_ glc ), specific production rate of lactate (q_ lac ), lactate transform rate (Y_ lac/glc ) and amino acids utilization as the evaluation indexes, the growth and metabolism of HEK293 cells under carrier-free immobilization culture mode were examined and compared with those of HEK293 cells cultured in static tissue flasks. It was found that HEK293 cells grown as suspended cell aggregates in spinner flasks maintained the basic growth and metabolism characteristics of HEK293 cells in stationary anchored culture, and HEK293 cells under carrier-free immobilization culture mode as suspended aggregates in stirred bioreactor facilitate perfusion performance and increase unit productivity. Cultivation of HEK293 cells in carrier-free immobilization culture mode has potential for further improving mammalian cells culture technique.

A High-throughput and Quantitative Assay Based on Fluorescence Intensity for Detection of Apoptosis / 中国生物工程杂志

Based on the different permeability of DNA-intercalant dyes YO-PRO-1(YP) and propidium iodide (PI) to the membrane of viable, apoptotic and necrotic cells, cell samples were stained with 4?mol/L YP and 4?g/ml PI for 10 min, and the fluorescence intensity of both YP and PI were measured by fluorometer at Ex/Em wavelength of 485/538nm and 530/590nm, respectively. The correlation between YP fluorescence intensity and the apoptotic cell number was confirmed by fluorescence microscope and linear regression(r=0.999,P

The Study and Design Methods of Serum-Free Medium for Animal Cells / 中国生物工程杂志

With the expanding scale of animal cell culture and increasing demand of biopharmaceutical,the development of serum-free medium based on cell lines and products has become a major task in the field of cell engineer.The statistical methods and tools are popular in the processes of design medium and can be used to evaluate the multiple factors and their interaction scientifically and effectively.The novel microarray and proteomic analysis can improve the performance of identifying the role of medium.The aim is to provide some idea for serum-free medium study through systematically summarizing the newly and commonly used serum-free medium study and design approaches and their characteristics.

Retroviral Expression System and Its Application in Efficient Foreign Gene Expression / 中国生物工程杂志

Retroviral expression system which consists of retroviral vector,envelop protein vector and packaging cell line is an efficient expression system for recombinant protein.It has great potential in gene therapy and biopharmacy.Transcriptional active genome regions are the preferred targets for retrovirus integration.Furthermore,VSV-G protein enables this system a broader host range and makes virus integration more efficient.After infection of high-titer virus,high production clones can be selected through simple screening.So far,the research on retrovirus expression system has developed into application in bio-pharmacy industry.Here the composition of this system and the mechanism of virus transduction and summarize the application and prospect of retroviral expression system are introduced.