A study on the sustainability assessment of China's basic medical insurance fund under the background of population aging-evidence from Shanghai.

Objective: As China's population aging process accelerates, the expenditure of China's basic medical insurance fund for employees may increase significantly, which may threaten the sustainability of China's basic medical insurance fund for employees. This paper aims to forecast the future development of China's basic medical insurance fund for employees in the context of the increasingly severe aging of the population. Methods: This paper taking an empirical study from Shanghai as an example, constructs an actuarial model to analyze the impact of changes in the growth rate of per capita medical expenses due to non-demographic factors and in the population structure on the sustainability of the basic medical insurance fund for employees. Results: Shanghai basic medical insurance fund for employees can achieve the goal of sustainable operation in 2021-2035, with a cumulative balance of 402.150-817.751 billion yuan in 2035. The lower the growth rate of per capita medical expenses brought about by non-demographic factors, the better the sustainable operation of the fund. Conclusion: Shanghai basic medical insurance fund for employees can operate sustainably in the next 15 years, which can further reduce the contribution burden of enterprises, which lays the foundation for improving the basic medical insurance treatment for employees.

Children's internal migration and subjective wellbeing of older parents left behind: Spiritual or financial support?

Introduction: Against the background of population aging and large-scale internal migration, this study uses an ordered logit with two-way fixed effects to examine the effect of children's internal migration on the subjective wellbeing of parents left behind. The study is based on the China Family Panel Studies database. Methods: Data were obtained from CFPS (China Family Panel Studies), and ordered logit with two-way fixed effects was used to test the total effect of children's internal migration on subjective wellbeing of parents left behind, and KHB test was used to separate intergenerational spiritual support and intergenerational financial support to examine the intergenerational support preferences of parents left behind. Results: The results show that children's internal migration has a significant negative effect on the subjective wellbeing of parents left behind, mainly through the reduction of intergenerational spiritual support. Furthermore, intergenerational financial support significantly mitigates this negative effect. There is heterogeneity in the direction of the total wellbeing effect across parents' preferences, as well as in the masking effect of financial support. However, the effect of financial support never fully offsets the effect of spiritual support. Discussion: To cope with the negative effects of children's internal migration on parents, positive measures should be taken to change parental preferences.

Systematic Functional Analysis of Sigma (σ) Factors in the Phytopathogen Xanthomonas campestris Reveals Novel Roles in the Regulation of Virulence and Viability.

The black rot pathogen Xanthomonas campestris pv. campestris (Xcc) is a model organism for the study of plant bacterial pathogenesis mechanisms. In bacteria, σ factors serve as important regulatory elements that respond to various environmental signals and cues. Though Xcc encodes 15 putative σ factors little is known about their roles. As an approach to identify the potential role of each σ factor, we constructed mutations in each of the σ-factor genes as well as generating mutants deficient in multiple σ factors to assess these regulators potential additive functions. The work identified two σ70 factors essential for growth. Furthermore, the work discovered a third σ70 factor, RpoE1, important for virulence. Further studies revealed that RpoE1 positively regulates the expression of the hrp gene cluster that encodes the type III secretion system (T3SS) which determines the pathogenicity and hypersensitive response of Xcc on plants. In vivo and in vitro studies demonstrated that RpoE1 could bind to the promoter region and promote transcription of hrpX, a gene encoding a key regulator of the hrp genes. Overall, this systematic analysis reveals important roles in Xcc survival and virulence for previously uncharacterized σ70 factors that may become important targets for disease control.

A new immunosuppressive pregnane glycoside from aqueous fraction of Epigynum cochinchinensis.

Chemical investigation on the aqueous fraction of the stems of Epigynum cochinchinensis led to the isolation of a new pregnane glycoside named as epigycoside A (1) along with three known analogues (2-4). The structure of compound 1 was elucidated by means of spectroscopic techniques, including HRESIMS, and 1D and 2D NMR experiments. The immunosuppressive activity of 1 was evaluated by an in vitro model of concanavalin A-induced mice splenocytes proliferation. Compound 1 showed significant inhibitory activity in a dose-dependent manner, closer to the efficacy of positive control, dexamethasone, at a concentration of 50 µM.

Seco-pregnane glycosides from the stems of Epigynum auritum.

Chemical investigation of the stems of Epigynum auritum led to the isolation and identification of a novel 16,17-seco pregnane glycoside, epigynoside D, along with other three known compounds (2-4). The structure of compound 1 was elucidated by means of spectroscopic analysis, including HRESIMS, 1D and 2D NMR experiments. All isolated compounds were tested for their in vitro cytotoxic, immunological and anti-acetylcholinesterase activities.

Effects of TGF-ß1 and alginate on the differentiation of rabbit bone marrow-derived mesenchymal stem cells into a chondrocyte cell lineage.

The aim of the present study was to investigate the effect of a three-dimensional (3D) culture system of sodium alginate gel on the directional differentiation induction of bone marrow-derived mesenchymal stem cells (BMSCs) into chondrocytes, as well as the in vitro gene transfection technique. The biological characteristics of the passage and proliferation of rabbit BMSCs were investigated under conditions of in vitro monolayer and 3D culture of sodium alginate gel. Transforming growth factor (TGF)-ß1 gene recombinant adenoviral cosmid vectors and the recombinant adenoviral vector Ad.TGF-ß1 were constructed, and the effect of Ad.TGF-ß1 transfection on the differentiation of BMSCs into chondrocytes was investigated. The whole bone marrow rinsing method was used to obtain, separate and purify the rabbit BMSCs, and the in vitro monolayer and 3D culture of sodium alginate gel were thus successfully and stably established. A safe, stable and efficient method of constructing Ad.TGF-ß1 TGF-ß1 gene recombinant adenoviral vectors was established. Following TGF-ß1 transfection, BMSCs were able to continuously secrete significantly increased amounts of specific extracellular matrix components of chondrocytes, such as collagen II and proteoglycans. Furthermore, the effects in the post-gene transfection 3D culture group were found to be enhanced compared with those in the monolayer culture group. In conclusion, the 3D culture system of sodium alginate gel and in vitro gene transfection exhibited significant inductive effects on differentiation, which could be used to promote BMSCs to differentiate into chondrocytes.

A novel Wnt5a-Frizzled4 signaling pathway mediates activity-independent dendrite morphogenesis via the distal PDZ motif of Frizzled 4.

The morphology of the dendritic tree is critical to neuronal function and neural circuit wiring. Several Wnt family members have been demonstrated to play important roles in dendrite development. However, the Wnt receptors responsible for mediating this process remain largely elusive. Using primary hippocampal neuronal cultures as a model system, we report that Frizzled4 (Fzd4), a member of the Fzd family of Wnt receptors, specifically signals downstream of Wnt5a to promote dendrite branching and growth. Interestingly, the less conserved distal PDZ binding motif of Fzd4, and not its conserved proximal Dvl-interacting PDZ motif, is required for mediating this effect. We further showed that Dvl signaled parallel to and independent of Fzd4 in promoting dendrite growth. Unlike most previously described pathways, Wnt5a/Fzd4 signaling promoted dendrite development in an activity-independent and autocrine fashion. Together, these results provide the first identification of a Wnt receptor for regulating dendrite development in the mammalian system, and demonstrate a novel function of the distal PDZ motif of Fzd4 in dendrite morphogenesis, thereby expanding our knowledge of the complex roles of Wnt signaling in neural development.

Extracellular matrix of mechanically stretched cardiac fibroblasts improves viability and metabolic activity of ventricular cells.

BACKGROUND: In heart, the extracellular matrix (ECM), produced by cardiac fibroblasts, is a potent regulator of heart's function and growth, and provides a supportive scaffold for heart cells in vitro and in vivo. Cardiac fibroblasts are subjected to mechanical loading all the time in vivo. Therefore, the influences of mechanical loading on formation and bioactivity of cardiac fibroblasts ECM should be investigated. METHODS: Rat cardiac fibroblasts were cultured on silicone elastic membranes and stimulated with mechanical cyclic stretch. After removing the cells, the ECMs coated on the membranes were prepared, some ECMs were treated with heparinase II (GAG-lyase), then the collagen, glycosaminoglycan (GAG) and ECM proteins were assayed. Isolated neonatal rat ventricular cells were seeded on ECM-coated membranes, the viability and lactate dehydrogenase (LDH) activity of the cells after 1-7 days of culture was assayed. In addition, the ATPase activity and related protein level, glucose consumption ratio and lactic acid production ratio of the ventricular cells were analyzed by spectrophotometric methods and Western blot. RESULTS: The cyclic stretch increased collagen and GAG levels of the ECMs, and elevated protein levels of collagen I and fibronectin. Compared with the ECMs produced by unstretched cardiac fibroblasts, the ECMs of mechanically stretched fibroblasts improved viability and LDH activity, elevated the Na⁺/K⁺-ATPase activity, sarco(endo)plasmic reticulum Ca²âº-ATPase (SERCA) activity and SERCA 2a protein level, glucose consumption ratio and lactic acid production ratio of ventricular cells seeded on them. The treatment with heparinase II reduced GAG levels of these ECMs, and lowered these metabolism-related indices of ventricular cells cultured on the ECMs. CONCLUSIONS: Mechanical stretch promotes ECM formation of cardiac fibroblasts in vitro, the ECM of mechanically stretched cardiac fibroblasts improves metabolic activity of ventricular cells cultured in vitro, and the GAG of the ECMs is involved in regulating metabolic activity of ventricular cells.

Counter-effect of constrained dynamic loading on osteoporosis in ovariectomized mice.

In recent years, dynamic mechanical loading has been shown to effectively enhance bone remodeling. The current study attempted to research the counter-effect of constrained dynamic loading on osteoporosis (OP) in ovariectomized (OVX) mice. Female Kunming (KM) mice were randomly divided into 2 groups: SHAM and OVX. The right ulnas of the OVX mice were subjected to a 4-week constrained dynamic loading protocol, and the mechanical properties, trabecular micromorphology parameters and biochemical indices of osteogenesis were evaluated. We detected higher levels of tissue alkaline phosphatase (AKP) and serum bone gamma-carboxyglutamic-acid-containing proteins (BGPs), better trabecular micromorphology parameters and ulnar mechanical properties in the loading group than in the nonloading group. In summary, constrained dynamic loading could prevent ovariectomy-induced osteoporosis by facilitating osteogenesis, improving trabecular microstructure and enhancing bone mechanical properties.

Mechanical stimulus inhibits the growth of a bone tissue model cultured in vitro △.

OBJECTIVES: To construct the cancellous bone explant model and a method of culturing these bone tissues in vitro, and to investigate the effect of mechanical load on growth of cancellous bone tissue in vitro. METHODS: Cancellous bone were extracted from rabbit femoral head and cut into 1-mm-thick and 8-mm-diameter slices under sterile conditions. HE staining and scanning electron microscopy were employed to identify the histomorphology of the model after being cultured with a new dynamic load and circulating perfusion bioreactor system for 0, 3, 5, and 7 days, respectively. We built a three-dimensional model using microCT and analyzed the loading effects using finite element analysis. The model was subjected to mechanical load of 1000, 2000, 3000, and 4000 µÎµ respectively for 30 minutes per day. After 5 days of continuous stimuli, the activities of alkaline phosphatase (AKP) and tartrate-resistant acid phosphatase (TRAP) were detected. Apoptosis was analyzed by DNA ladder detection and caspase-3/8/9 activity detection. RESULTS: After being cultured for 3, 5, and 7 days, the bone explant model grew well. HE staining showed the apparent nucleus in cells at the each indicated time, and electron microscope revealed the living cells in the bone tissue. The activities of AKP and TRAP in the bone explant model under mechanical load of 3000 and 4000 µÎµ were significantly lower than those in the unstressed bone tissues (all P<0.05). DNA ladders were seen in the bone tissue under 3000 and 4000 µÎµ mechanical load. Moreover, there was significant enhancement in the activities of caspase-3/8/9 in the mechanical stress group of 3000 and 4000 µÎµ(all P<0.05). CONCLUSIONS: The cancellous bone explant model extracted from the rabbit femoral head could be alive at least for 7 days in the dynamic load and circulating perfusion bioreactor system, however, pathological mechanical load could affect the bone tissue growth by apoptosis in vitro. The differentiation of osteoblasts and osteoclasts might be inhibited after the model is stimulated by mechanical load of 3000 and 4000 µÎµ.

[Residue of chlorpyrifos and its degradation dynamics in Chinese chive (Allium tuberosum) plant and soil].

This paper studied the residue of chlorpyrifos and its degradation dynamics in Chinese chive (Allium tuberosum) plant and soil after irrigating different concentrations of this pesticide into A. tuberosum root zone under plastic greenhouse and open-field cultivated conditions. The chlorpyrifos in A. tuberosum plant had a faster degradation rate than that in soil, with an average half-life of the pesticide being 3.41 and 7.40 days in the plant and soil, respectively. Under the conditions of plastic greenhouse and open-field cultivation, the degradation rate of chlorpyrifos in A. tuberosum plant had less difference, with the average half-life of chlorpyrifos being 3.37 and 3.44 days, respectively. 21 days after irrigating into root zone, the chlorpyrifos (0.021-0.102 mg x kg(-1)) in A. tuberosum plant did not exceed the maximum residue limit (< or = 0.01 mg x kg(-1), GB 2763-2005). A few chlorpyrifos residue was found in the new growth parts of A. tuberosum, but the residue concentration was obviously lower than that in the first harvested plant after irrigating this pesticide. The chlorpyrifos residue in soil had significant effects on the residue of the pesticide in A. tuberosum plant.

Involvement of p38MAPK/NF-κB signaling pathways in osteoblasts differentiation in response to mechanical stretch.

Bone morphogenetic proteins (BMPs) are known to be important in osteoblasts' response to mechanical stimuli. BMPs/Smad signaling pathway has been demonstrated to play a regulatory role in the mechanical signal transduction in osteoblasts. However, little is currently known about the Smad independent pathway in osteoblasts differentiation in mechanical loading. In this study, MC3T3-E1 cells were subjected to mechanical stretch of 2000 micro-stain (µÎµ) at 0.5 Hz, in order to investigate the involvement of p38MAPK and NF-κB signaling pathways in mechanical response in osteoblasts. We found BMP-2/BMP-4 were up-regulated by mechanical stretch via the earlier activation of p38MAPK and NF-κB signaling pathways, which enhanced osteogenic gene expressions including alkaline phosphatase (ALP), collagen type I (Col I) and osteocalcin (OCN), and the expressions of these osteogenic genes were remarkably decreased with Noggin (an inhibitor for BMPs signals) pretreatment. Furthermore, BMP-2/BMP-4 expressions were suppressed by PDTC, an inhibitor of NF-κB pathway and SB203580, an inhibitor of p38MAPK pathway, respectively, leading to the declined levels of ALP, Col I and OCN. Interestingly, blocking in p38MAPK pathway can also cause the inactivation of NF-κB pathway in mechanical stretch. Collectively, the results indicate during mechanical stretch p38MAPK and NF-κB signaling pathways are activated first, and then up-regulate BMP-2/BMP-4 to enhance osteogenic gene expressions. Moreover, p38MAPK and NF-κB signals have cross-talk in regulation of BMP-2/BMP-4 in mechanical response.

[Safety and immunogenicity of Bilive combined hepatitis A and B vaccine].

OBJECTIVE: To study the safety and immunogenicity of the Bilive combined hepatitis A and B vaccine produced by Sinovac Biotech Co., Ltd. METHODS: Samples were selected from first year students of a senior high school (adults group) and first to fifth grade 1-5 students of 3 primary schools (children group). Those who were susceptible to both hepatitis A virus (HAV) and hepatitis B virus (HBV), HAV only or HBV only were assigned to group AB, A and B respectively and were vaccinated with three doses (0, 1 and 6 month schedule) of Bilive combined hepatitis A and B vaccine, inactivated hepatitis A vaccine and recombined hepatitis B vaccine respectively. The dosage for adult group was 500 U hepatitis A antigen and/or 10 micro g hepatitis B surface antigen and the dosage for children group was half the dosage of adult group. The potential adverse effects were observed within 72 hours after vaccination. Serum samples were collected for testing anti-HAV and anti-HBs at month 2 and 7 after the initial dose. RESULTS: The rates of local adverse effects were 0.58% and 2.56% in children AB group and adults AB group and the general adverse effects rates were 9.88% and 5.45% respectively. Both local and general adverse effect rates were not significantly different to the control group. The sero-conversion rate of anti-HAV in children and adults AB group reached 100%, one month after 3 doses. The geometric mean titer (GMTs) reached 33,910 mIU/ml and 23,435 mIU/ml respectively, significant higher than that in control group (group A). The sero-conversion rates of anti-HBs were 97.30% and 96.63%, and GMTs were 103 mIU/ml and 102 mIU/ml in children and adults AB group respectively. No significant difference on sero-conversion and GMT was observed when compared with control group. CONCLUSION: The Bilive combined hepatitis A and B vaccine had good safety profile, and the immunogenicity both on anti-HAV and anti-HBs was similar to that of separated components.

[Genomic sequence of hepatitis A virus L-A-1 vaccine strain].

OBJECTIVE: To study the genome sequence of hepatitis A virus L-A-1 strain which has been applied for live attenuated vaccine production in China, to compare with other HAV strains, to understand some characteristics of L-A-1 strain, and to find the mechanism of attenuation and cell adaptation. METHODS: Genome fragments were prepared by antigen-capture PCR from infected cell (2BS), PCR products were cloned into T vector, sequenced and analyzed by using bioinformatics program. RESULTS: Analysis of the genomic sequences(nt 25-7,418) showed that the open reading frame contains 6,675 nucleotides in length encoding 2,225 amino acids. Sequence homology comparison showed 98.00% and 94.00% homology at nucleotide level, and 98.51% and 98.65% homology at amino acid level with international strains MBB and HM 175, respectively. Through comparison with other attenuated, cell adapted and cytopathic effect (CPE) strains, L-A-1 strain had mutation at nt 152, 591, 646, 687 and insertion at nt 180-181 in 5?NTR and had mutation at nt 3,889 (aa 1 052-Val) in 2B region, these mutations and insertion are molecular basis for cell adaptation; mutation at nt 4,185 (aa 1 152-Lys) in 2C region should be attenuated marker; deletion in 3A region (nt 5,020-5,025) that caused two amino acids deletion is virus fast growth basis. CONCLUSION: Through analyzing L-A-1 strain genomic sequence, certain sites related to cell adaptation and attenuation were found.