Wnt5a deficiency in osteocalcin-expressing cells could not alleviate the osteoarthritic phenotype in a mouse model of post-traumatic osteoarthritis.

Objectives: Wnt5a, which regulates the activities of osteoblasts and osteoclasts, is reportedly overexpressed in osteoarthritis (OA) tissues. The purpose of this study was to elucidate its role in the development of OA by deleting Wnt5a in osteocalcin (OCN)-expressing cells. Materials and Methods: Knee OA was induced by anterior cruciate ligament transection (ACLT) in OCN-Cre;Wnt5afl/fl knockout (Wnt5a-cKO) mice and control littermates. Eight weeks after surgery, histological changes, cell apoptosis, and matrix metabolism of cartilage were evaluated by toluidine blue, TUNEL staining, and im-immunohistochemistry analyses, respectively. In addition, the subchondral bone microarchitecture of mice was examined by micro-computed tomography (micro-CT). Results: Histological scores show substantial cartilage degeneration occurred in ACLT knees, coupled with decreased collagen type II expression and enhanced matrix metalloproteinase 13 expression, as well as higher proportions of apoptotic cells. Micro-CT results show that ACLT resulted in decreased bone mineral density, bone volume/trabecular volume, trabecular number, and structure model index of subchondral bones in both Wnt5a-cKO and control littermates; although Wnt5a-cKO mice display lower BMD and BV/TV values, no significant difference was observed between Wnt5a-cKO and control mice for any of these values. Conclusion: Our findings indicate that Wnt5a deficiency in OCN-expressing cells could not prevent an osteoarthritic phenotype in a mouse model of post-traumatic OA.

Associations between physical activity intensity and body compositions in adolescents / 中国学校卫生

Objective@#To study the specific correlation between physical activity intensities and body compositions of adolescents and to provide guidance for the improvement of various body compositions of Chinese adolescents.@*Methods@#From September to December 2019, body composition measurement based on bioelectrical impedance analyzer and the physical activity measurement based on accelerometers were performed among 971 adolescents from 8 high schools, such as Tsinghua Middle School in Beijing, by random number coding sampling. Statistical analysis was conducted by using independent sample t test, Pearson correlation coefficient method and multiple linear regression method.@*Results@#Sedentary behavior(SB) of the junior and senior high school boys was significantly lower than that of girls, while the VPA(vigorous physical activity) and moderate vigorous physical activity(MVPA) were significantly higher than those of boys ( t =-1.98, -8.09; 5.20, 4.52; 3.53, 4.03, P <0.05). light physical activity(LPA) and moderate physical activity(MPA) of boys were significantly higher than those of girls in the senior high schools ( t =3.67, 5.63, P <0.01). Lean mass(LM) of the junior school boys was correlated to their MVPA( β =0.302), bone mineral content(BMC) was quantitively related to SB( β =-0.001), MVPA( β =0.002), and fat mass(FM) was related to SB( β =0.050), and MVPA( β =-0.323) ( P <0.05). LM of junior school girls was quantitively correlated to LPA ( β =0.080) and MVPA( β =0.613). And there was also correlation among BMC ,SB( β =-0.004) and MVPA( β =0.008) between FM and MVPA( β =-0.237) ( P <0.05) . There was a correlation between total body LM and MVPA ( β =0.393), total body BMC and SB ( β =-0.001), MVPA ( β =0.002), and total body FM and MVPA ( β =-0.393) in senior high school boys( P <0.05). There was a correlation between senior high school girls’ total body LM and LPA ( β =0.063), MVPA ( β =0.601), total body FM and SB ( β =0.029), and MVPA ( B =-0.529)( P <0.05).@*Conclusion@#There are gender differences and correlations between adolescent physical activity intensity and body composition. It is recommended that relevant departments provide personalized physical activity dose guidance for adolescents to improve their physical fitness.

[Overview of research and development of polypeptide drugs and traditional Chinese medicine-peptides].

Peptide is a compound consisting of 2-50 amino acids, which is intermediate between small molecule and protein. It is characterized by a variety of biological activities, easy absorption, strong specific targeting, and few side effects and has become one of the hotspots in biomedical research in recent years. Chinese medicine contains a large number of peptides. The traditional processing methods such as decocting and boiling can effectively boost peptides to exert their due biological activities. At present, however, the research on Chinese medicinal components in laboratory generally employs high-concentration alcohol extraction method, which may cause the peptides to be ignored in many natural Chinese medicines. Substantial studies have revealed that the peptides in Chinese medicine are important material basis responsible for the traditional efficacy. Based on years of research and literature retrieval, this study put forward the concept of "traditional Chinese medicine(TCM)-peptides", referring to the components consisting of two or more amino acids with molecular weight between small molecules and proteins that can express the efficacy of Chinese medicine. Furthermore, this study also summarized the extraction and separation of TCM-peptides, and structure determination methods and routes, predicted the research prospect of modern research methods of TCM-peptides based on "holistic view" and big data. The artificial intelligence prediction was combined with high-throughput screening technology to improve the discovery efficiency and accuracy of TCM-peptides, and holographic images between TCM-peptides and biological targets were established to provide references for the innovative drug design and related health product development of TCM-peptides based on TCM theories.

[Effects of Side-effect Attenuation Prescriptions on Cyclophosphamide-induced Myelosuppression in Mice].

OBJECTIVE: To determine the effects of Side-effect Attenuation Prescriptions on the levels of white blood cells (WBC), hemoglobin (HGB) and platelet (PLT) in peripheral blood of mice influenced by cyclophosphamide (CTX). METHODS: Mice were randomly divided into 6 groups: normal control group, myelosuppression group induced by CTX (model group), recombinant human granulocyte colony stimulating factor (G-CSF) group, and Side-effect Attenuation Prescriptions group (experimental groups with high, middle, and low dosages). Marrow depressed models were established by injecting CTX intraperitoneally (40 mg/kg, once/d, 10 d) to the mice. High, middle, and low dosage experimental groups received 40 g/kg, 20 g/kg, and 10 g/kg Side-effect Attenuation Prescriptions once a day for two weeks, respectively. Mice in the G-CSF group were given G-CSF (50 µg/kg) by hypodermic injection three days before blood sampling. Levels of WBC, HGB and PLT counts in peripheral bloods of the mice were detected at 7 d and 14 d after the marrow depressed models were established. RESULTS: The Side-effect Attenuation Prescriptions slowed down the decline of blood levels of WBC, HGB and PLT induced by CTX (P < 0.05), and accelerated the recovery of WBC and HGB levels compared with model group at 14 d (P < 0.05). CONCLUSION: The Side-effect Attenuation Prescriptions can accelerate recovery of WBC, HGB and PLT in peripheral bloods of mice.

Polydatin protects learning and memory impairments in a rat model of vascular dementia.

Polydatin is one of the most common encountered stilbenes of nature and a key component of the Chinese herb Polygonum cuspidatum. This study is to investigate the effects of polydatin on learning and memory impairments induced by chronic cerebral hypoperfusion in rats, as well as the potential mechanism. Both common carotid arteries and both vertebral arteries occlusion (four-vessel occlusion, 4-VO) induced severe cognitive deficits tested by water maze task, along with oxidative stress in hippocampus. Oral administration of polydatin for 30 days markedly attenuated cognitive deficits compared with the control (p < 0.05). Biochemical determination revealed that polydatin decreased the production of malondialdehyde (MDA) and significantly increased the activities of superoxide dismutase (SOD) and catalase (CAT). Additionally, polydatin effectively alleviated the injuries of cultured neurons induced by oxygen-glucose deprivation (OGD). These results suggest that polydatin exhibit therapeutic potential for vascular dementia, which is most likely related, at least in part, to its anti-oxidant activity and the direct protection of neurons.

Oxidative stress and peripheral skeletal muscle dysfunction in rats with emphysema.

BACKGROUND: Peripheral skeletal muscle dysfunction in patients with chronic obstructive pulmonary disease (COPD) may be due to the disease per se or as a result of concomitant confounding factors. Although the mechanistic basis for this functional impairment is uncertain, oxidative stress may play a role. The purpose of this study was to investigate whether local oxidative stress is associated with the reduced peripheral skeletal muscle performance in rats with emphysema. METHODS: In situ mechanical properties of gastrocnemius were measured in Sprague-Dawley rats 5 months after intratracheal instillation of either elastase (EMP, n = 10) or normal saline (CON, n = 10). Lipofuscin inclusions, myocyte apoptosis and antioxidant enzyme activities were examined in the gastrocnemius muscle. RESULTS: Lipofuscin inclusions were significantly higher in the gastrocnemius muscle of EMP compared with CON (3.2 + or - 0.4 vs. 1.7 + or - 0.4, P < 0.01). The activities of antioxidant enzymes were significantly increased in muscle homogenates of EMP as compared to CON. No significant differences were found in myocyte apoptosis between EMP and CON (1.2 + or - 0.9 vs. 1.0 + or - 0.8, P > 0.05). EMP decreased the fatigue endurance of gastrocnemius muscle (half-time to fatigue recovery: (150.0 + or - 55.4) seconds vs. (55.2 + or - 29.3) seconds, P < 0.01) and had no effect on maximal tetanic force ((467.4 + or - 36.6) g vs. (493.2 + or - 30.5) g, P > 0.05). A significantly positive correlation was found between the level of lipofuscin inclusions and the half-time to fatigue recovery of gastrocnemius muscle in EMP (r = 0.664, P < 0.05). CONCLUSION: Local oxidative stress may have important functional consequences for peripheral skeletal muscle in rats with EMP.

Using oligonucleotide suspension arrays for laboratory identification of bacteria responsible for bacteremia.

The aim of this study was to develop and validate an oligonucleotide suspension array for rapid identification of 15 bacterial species responsible for bacteremia, particularly prevalent in Chinese hospitals. The multiplexed array, based on the QIAGEN LiquiChip Workstation, included 15 oligonucleotide probes which were covalently bound to different bead sets. PCR amplicons of a variable region of the bacterial 23S rRNA genes were hybridized to the bead-bound probes. Thirty-eight strains belonging to 15 species were correctly identified on the basis of their corresponding species-specific hybridization profiles. The results show that the suspension array, in a single assay, can differentiate isolates over a wide range of strains and species, and suggest the potential utility of suspension array system to clinical laboratory diagnosis.

[Ion channel mechanism of regulatory volume decrease in human epithelial cells].

AIM: To observe the regulatory volume decrease (RVD) process of human intestine cells and investigate its ion channel mechanism. METHODS: Cultured human intestine cells were exposed to hypotonic solution and the cell volume was measured using Coulter Counter System. RT-PCR was explored to detect the mRNA expression of Ca(2+) -activated K+ channel. RESULTS: Human intestine cells showed a RVD process and this process could be blocked by Cl- channel blocker NPPB and K+ channel blocker TEA. Further results demonstrated the subtype of K+ channel involved in RVD was an intermediate-conductance, Ca(2+) -activated K+ channel (IK) because of its high sensitivity to clotrimazole. RT-PCR results also showed the expression of IK in this cell line. CONCLUSION: The RVD process of intestine cell was dependent on the parallel activation of Cl- channel and K+ channel. The subtype of K+ channel in volved in the RVD process was IK channel.

[Identification of closely related bacteria via phylogenetic methods].

OBJECTIVE: To differentiate closely related pathogenic bacteria via phylogenetic method on the basis of gyrB gene sequences. METHODS: GyrB sequences of 19 strains of E.coli, 13 Shigella spp. 2 Aeromonas caviae, 2 Aeromonas hydrophilia,1 Aeromonas veronii were determined and combined with sequences retrieved from public databases to construct phylogenetic trees. For each sequence tested, the identification deduced from the clustering relation of sequences was compared with the phenetic identification. RESULTS: All the tested sequences, except those of Shigella boydii and Shigella dysenteriae, were corresponded with the 5 closest sequences on the tree at the species level. While the BLAST queries returned some other bacteria organisms or undetermined entries. CONCLUSION: Phylogenetics displays good discriminative power in bacterial sequences differentiation.

Effects of arsenic on seed germination and physiological activities of wheat seedlings.

The effects of arsenic (As) were investigated on seed germination, root and shoot length and their biomass and some other factors to elucidate the toxicity of As. The results showed low concentrations of As (0-1 mg/kg) stimulated seed germination and the growth of root and shoot, however, these factors all decreased gradually at high concentrations of As (5-20 mg/kg). The contents of O2*-, MDA, soluble protein and peroxidase (POD) activity all increased with increasing As concentrations. Soluble sugar content, ascorbate peroxidase (APX), and superoxide dismutase (SOD) activities decreased at low concentrations of As, and increased at high concentrations of As. While acetylsalicylic acid (ASA) and chlorophyll contents, catalase (CAT) activity displayed increasing trend when the concentrations of As was lower than 1 mg/kg, and then decreasing trend. By polyacrylamide gel electrophoresis (PAGE), As induced the expression of POD isozymes of wheat seedlings. As induced the expression of CAT isozymes but inhibited the expression of SOD isozymes of wheat seedlings at concentrations lower than 1 mg/kg. However, As inhibited the expression of CAT isozymes but induced the expression of SOD isozymes at concentrations higher than 5 mg/kg. The results indicated As could exert harmfulness in the early development stage of wheat at inappropriate concentrations.

[Study on the fluorescence characteristics of the interaction between DNA and two halogenated fluoresceins].

The fluorescence characteristics of the interaction between DNA and two halogen fluoresceins, tetrabromofluorescein (TBF) and tetrachlorotetrabromofluorescein (TTF), were studied. The result showed that for TBF, lamda ex/ lamda em were 518 nm/540 nm, and for TTF, they were 540 nm/560 nm. The intensity of fluorescence of TBF and TTF changed in the presence of DNA. The fluorescence quenching studies indicated that TBF binds to DNA in the groove and the polarization experiments showed that TBF is intercalated into the DNA base pairs. So the comprehensive interaction mode of TBF with DNA may be that TTF is intercalated into DNA base pairs and binds to DNA in the groove. Both the fluorescence quenching studies and the polarization experiments indicated that TTF is intercalated into the DNA base pairs. It was also found that ionic strength could affect the interaction of TBF/TTF and DNA. The binding constants K are 1 x 10(6) L x mol(-1) and 2 x 10(6) L x mol(-1), and the binding site numbers n are 0.62 and 0.16 for TBF and TTF, respectively.

[Classification and identification of vibrio cholerae and vibrio parahaemolyticus isolates based on gyrB gene phylogenetic analysis].

In order to validate the usefulness of gyrB genotype for the classification and identification of Vibrio cholerae and Vibrio parahaemolyticus isolates, the phylogenetic analysis of 13 V. cholerae, 8 V. parahaemolyticus, 2 Aeromonas hydrophila and 1 Plesiomonas shigelloides strains was carried out using the partial coding sequence of gyrB, a gene that encodes the B subunit of DNA gyrase (topoisomerase type II ) in bacteria. These strains were separately clustered at species level and typed by the DNA sequences of reference strains from GenBank. CtxA positive V. cholerae strains including 8 clincical isolates of 0139 and 2 clinical isolates of 01 formed one cluster. Four V. parahaemolyticus strains of 1 isolate from 2002 Zhejiang outbreak patient ( tdh positive), 2 clinical isoltates from 2004 and 1 strain from Japan were grouped with an environmental isolate ( trh positive) from 2001. GyrB genotype is applicable to species identification of V. cholerae, V. parahaemolyticus, A. hydrophila and P. shigelloides isolates. The ctxA positive 0139 and 01 group of V. cholerae are closely related, as reflected by gyrB sequence divergence. Furthermore, the toxigenic V. parahaemolyticus strain isolated from environments may be the potential pathogen to the local prevalent and sporadic cases.

[Inhibition of HBV core antigen gene expression in human embryonic kidney cell line AD293 by plasmid-based RNAi].

OBJECTIVE: To inhibit HBV core antigen gene expression with plasmid-based RNAi. METHODS: The shRNA expression vector targeting HBV core antigen gene was designed and constructed. Human embryonic kidney cell line AD293 was co-transfected with HBcAg-EGFP fusion protein expression vector and shRNA expression vector transiently, and the cells without shRNA-transfection and with non-specific shRNA transfection were used as controls. Inhibitory effect of RNAi was detected by fluorescence-activated cell sorting (FACS) and real-time fluorescence quantificational RT-PCR. RESULTS: HBV core antigen gene expression in AD293 was inhibited by shRNA, with the maximal inhibition rate of 76 % measured by FACS and of 63.1 % by real-time PCR. CONCLUSION: Effective inhibition of HBV core antigen gene expression by plasmid-based RNAi provides an alternative for anti-HBV study in vitro, which has potential clinical application.