PKM2 functions as a histidine kinase to phosphorylate PGAM1 and increase glycolysis shunts in cancer.

Phosphoglycerate mutase 1 (PGAM1) is a key node enzyme that diverts the metabolic reactions from glycolysis into its shunts to support macromolecule biosynthesis for rapid and sustainable cell proliferation. It is prevalent that PGAM1 activity is upregulated in various tumors; however, the underlying mechanism remains unclear. Here, we unveil that pyruvate kinase M2 (PKM2) moonlights as a histidine kinase in a phosphoenolpyruvate (PEP)-dependent manner to catalyze PGAM1 H11 phosphorylation, that is essential for PGAM1 activity. Moreover, monomeric and dimeric but not tetrameric PKM2 are efficient to phosphorylate and activate PGAM1. In response to epidermal growth factor signaling, Src-catalyzed PGAM1 Y119 phosphorylation is a prerequisite for PKM2 binding and the subsequent PGAM1 H11 phosphorylation, which constitutes a discrepancy between tumor and normal cells. A PGAM1-derived pY119-containing cell-permeable peptide or Y119 mutation disrupts the interaction of PGAM1 with PKM2 and PGAM1 H11 phosphorylation, dampening the glycolysis shunts and tumor growth. Together, these results identify a function of PKM2 as a histidine kinase, and illustrate the importance of enzyme crosstalk as a regulatory mode during metabolic reprogramming and tumorigenesis.

Congenital dual anterior interventricular artery.

Dual anterior interventricular artery is a rare type of CHD. We reported a fifteen-year-old girl who underwent CT angiography that demonstrated one anterior interventricular artery from aorta and another from pulmonary artery.

Fucoxanthin Induces Ferroptosis in Cancer Cells via Downregulation of the Nrf2/HO-1/GPX4 Pathway.

This study investigated the mechanism by which fucoxanthin acts as a novel ferroptosis inducer to inhibit tongue cancer. The MTT assay was used to detect the inhibitory effects of fucoxanthin on SCC-25 human tongue squamous carcinoma cells. The levels of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), glutathione (GSH), superoxide dismutase (SOD), malondialdehyde (MDA), and total iron were measured. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting were used to assess glutathione peroxidase 4 (GPX4), nuclear factor erythroid 2-related factor 2 (Nrf2), Keap1, solute carrier family 7 member 11 (SLC7A11), transferrin receptor protein 1 (TFR1), p53, and heme oxygenase 1 (HO-1) expression. Molecular docking was performed to validate interactions. Compared with the control group, the activity of fucoxanthin-treated SCC-25 cells significantly decreased in a dose- and time-dependent manner. The levels of MMP, GSH, and SOD significantly decreased in fucoxanthin-treated SCC-25 cells; the levels of ROS, MDA, and total iron significantly increased. mRNA and protein expression levels of Keap1, GPX4, Nrf2, and HO-1 in fucoxanthin-treated cells were significantly decreased, whereas levels of TFR1 and p53 were significantly increased, in a concentration-dependent manner. Molecular docking analysis revealed that binding free energies of fucoxanthin with p53, SLC7A11, GPX4, Nrf2, Keap1, HO-1, and TFR1 were below -5 kcal/mol, primarily based on active site hydrogen bonding. Our findings suggest that fucoxanthin can induce ferroptosis in SCC-25 cells, highlighting its potential as a treatment for tongue cancer.

[Inhibition of glutaminolysis alleviates myocardial fibrosis induced by angiotensin II].

The present study was aimed to investigate the role and mechanism of glutaminolysis of cardiac fibroblasts (CFs) in hypertension-induced myocardial fibrosis. C57BL/6J mice were administered with a chronic infusion of angiotensin II (Ang II, 1.6 mg/kg per d) with a micro-osmotic pump to induce myocardial fibrosis. Masson staining was used to evaluate myocardial fibrosis. The mice were intraperitoneally injected with BPTES (12.5 mg/kg), a glutaminase 1 (GLS1)-specific inhibitor, to inhibit glutaminolysis simultaneously. Immunohistochemistry and Western blot were used to detect protein expression levels of GLS1, Collagen I and Collagen III in cardiac tissue. Neonatal Sprague-Dawley (SD) rat CFs were treated with 4 mmol/L glutamine (Gln) or BPTES (5 µmol/L) with or without Ang II (0.4 µmol/L) stimulation. The CFs were also treated with 2 mmol/L α-ketoglutarate (α-KG) under the stimulation of Ang II and BPTES. Wound healing test and CCK-8 were used to detect CFs migration and proliferation respectively. RT-qPCR and Western blot were used to detect mRNA and protein expression levels of GLS1, Collagen I and Collagen III. The results showed that blood pressure, heart weight and myocardial fibrosis were increased in Ang II-treated mice, and GLS1 expression in cardiac tissue was also significantly up-regulated. Gln significantly promoted the proliferation, migration, mRNA and protein expression of GLS1, Collagen I and Collagen III in the CFs with or without Ang II stimulation, whereas BPTES significantly decreased the above indices in the CFs. α-KG supplementation reversed the inhibitory effect of BPTES on the CFs under Ang II stimulation. Furthermore, in vivo intraperitoneal injection of BPTES alleviated cardiac fibrosis of Ang II-treated mice. In conclusion, glutaminolysis plays an important role in the process of cardiac fibrosis induced by Ang II. Targeted inhibition of glutaminolysis may be a new strategy for the treatment of myocardial fibrosis.

Citrus-derived DHCP inhibits mitochondrial complex II to enhance TRAIL sensitivity via ROS-induced DR5 upregulation.

Heat-modified citrus pectin, a water-soluble indigestible polysaccharide fiber derived from citrus fruits and modified by temperature treatment, has been reported to exhibit anticancer effects. However, the bioactive fractions and their mechanisms remain unclear. In this current study, we isolated an active compound, trans-4,5-dihydroxy-2-cyclopentene-l-one (DHCP), from heat-treated citrus pectin, and found that is induces cell death in colon cancer cells via induction of mitochondrial ROS. On the molecular level, DHCP triggers ROS production by inhibiting the activity of succinate ubiquinone reductase (SQR) in mitochondrial complex II. Furthermore, cytotoxicity, apoptotic activity, and activation of caspase cascades were determined in HCT116 and HT-29 cell-based systems, the results indicated that DHCP enhances the sensitivity of cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), with DHCP-induced ROS accounting for the synergistic effect between DHCP and TRAIL. Furthermore, the combination of DHCP and TRAIL inhibits the growth of HCT116 and HT-29 xenografts synergistically. ROS significantly increases the expression of TRAIL death receptor 5 (DR5) via the p53 and C/EBP homologous protein pathways. Collectively, our findings indicate that DHCP has a favorable toxicity profile and is a new TRAIL sensitizer that shows promise in the development of pectin-based pharmaceuticals, nutraceuticals, and dietary agents aimed at combating human colon cancer.

Role of Circular RNAs in the Pathogenesis of Malignant Melanoma.

Malignant melanoma is one of the most aggressive types of skin cancer. Thus, efficient diagnosis and treatment methods are crucial for advanced melanoma. Circular RNAs (circRNAs) have been regarded as a 'splicing noise' in the past decades. However, several circRNAs have been recently reported to be differentially expressed in melanoma, and the cell or tissue-specific expression makes these suitable candidate diagnostic or therapeutic biomarkers. In addition, emerging studies have confirmed that circular RNAs play pivotal roles in the proliferation, invasion, metastasis, and migration of malignant melanoma. However, specific pathogenic mechanisms between melanoma and circRNAs remain unclear. In the present study, it was summarized that circRNAs are associated with the pathogenesis of melanoma, including hsa_circ_0083444, hsa_circ_0005320, hsa_circ_0067531, hsa_circ_0084043, hsa_circ_0000082, hsa_circ_0016418, hsa_circ_0085533 and hsa_circ_0025039, hsa_circ_0001946, hsa_circ_0002770, hsa_circ_0079593, hsa_circ_0027247, hsa_circ_0017247, hsa_circ_0020710. These can provide potential diagnosis, treatment, and prognostication biomarkers for advanced melanoma in clinical applications.

The potential pathogenic roles of S100A8/A9 and S100A12 in patients with MPO-ANCA-positive vasculitis.

BACKGROUND: The significance of S100A8/A9 and S100A12 in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) has not been clarified. This study was dedicated to exploring the potential pathogenic roles of S100A8/A9 and S100A12 in patients with myeloperoxidase (MPO)-ANCA-positive vasculitis. METHODS: Serum and urine concentrations of S100A8/A9 and S100A12 of forty-two AAV patients were evaluated. The influence of S100A8/A9 and S100A12 on the chemotaxis, the apoptosis, the release of IL-1ß, the complement activation, the respiratory burst, as well as the neutrophil extracellular traps (NETs) formation of MPO-ANCA-activated neutrophils was investigated. RESULTS: The serum and urine S100A8/A9 and S100A12 of active MPO-AAV significantly increased (compared with inactive AAV and healthy controls, p < 0.001) and were correlated with the severity of the disease. In vitro study showed that S100A8/A9 and S100A12 activated the p38 MAPK/NF-κB p65 pathway, increased the chemotaxis index (CI) and the release of IL-1ß, extended the life span, and enhanced the complement activation ability of MPO-ANCA-activated neutrophils. The Blockade of TLR4 and RAGE inhibited the effects of S100A8/A9 and S100A12. All above-mentioned effects of S100A8/A9 and S100A12 were ROS-independent because neither S100A8/A9 nor S100A12 enhanced the ROS formation and NETs formation of MPO-ANCA-activated neutrophils. CONCLUSION: S100A8/A9 and S100A12 serve as markers for assessing the disease severity, and they may also play a role in MPO-AAV pathogenesis.

A preliminary study on early postmortem submersion interval (PMSI) estimation and cause-of-death discrimination based on nontargeted metabolomics and machine learning algorithms.

Postmortem submersion interval (PMSI) estimation and cause-of-death discrimination of corpses in water have long been challenges in forensic practice. Recently, many studies have linked postmortem metabolic changes with PMI extension, providing a potential strategy for estimating PMSI using the metabolome. Additionally, there is a lack of potential indicators with high sensitivity and specificity for drowning identification. In the present study, we profiled the untargeted metabolome of blood samples from drowning and postmortem submersion rats at different PMSIs within 24 h by liquid chromatography-tandem mass spectrometry (LC-MS/MS). A total of 601 metabolites were detected. Four different machine learning algorithms, including random forest (RF), partial least squares (PLS), support vector machine (SVM), and neural network (NN), were used to compare the efficiency of the machine learning methods. Nineteen metabolites with obvious temporal regularity were selected as candidate biomarkers according to "IncNodePurity." Robust models were built with these biomarkers, which yielded a mean absolute error of 1.067 h. Additionally, 36 other metabolites were identified to build the classifier model for discriminating drowning and postmortem submersion (AUC = 1, accuracy = 95%). Our results demonstrated the potential application of metabolomics combined with machine learning in PMSI estimation and cause-of-death discrimination.

Inferring Postmortem Submersion Interval in Rats Found in Water Based on Vitreous Humor Metabolites.

OBJECTIVES: The metabolomics technique of LC-MS/MS combined with data analysis was used to detect changes and differences in metabolic profiles in the vitreous humor of early rat carcasses found in water, and to explore the feasibility of its use for early postmortem submersion interval (PMSI) estimation and the cause of death determination. METHODS: The experimental model was established in natural lake water with 100 SD rats were randomly divided into a drowning group (n=50) and a postmortem (CO2 suffocation) immediately submersion group (n=50). Vitreous humor was extracted from 10 rats in each group at 0, 6, 12, 18 and 24 h postmortem for metabolomics analyses, of which 8 were used as the training set to build the model, and 2 were used as test set. PCA and PLS multivariate statistical analysis were performed to explore the differences in metabolic profiles among PMSI and causes of death in the training set samples. Then random forest (RF) algorithm was used to screen several biomarkers to establish a model. RESULTS: PCA and PLS analysis showed that the metabolic profiles had time regularity, but no differences were found among different causes of death. Thirteen small molecule biomarkers with good temporal correlation were selected by RF algorithm. A simple PMSI estimation model was constructed based on this indicator set, and the data of the test samples showed the mean absolute error (MAE) of the model was 0.847 h. CONCLUSIONS: The 13 metabolic markers screened in the vitreous humor of rat corpses in water had good correlations with the early PMSI. The simplified PMSI estimation model constructed by RF can be used to estimate the PMSI. Additionally, the metabolic profiles of vitreous humor cannot be used for early identification of cause of death in water carcasses.

Neoadjuvant chemotherapy versus neoadjuvant chemoradiotherapy for locally advanced oesophageal squamous cell carcinoma: a single-Centre, open-label, randomized, controlled, clinical trial (HCHTOG1903).

BACKGROUND: Neoadjuvant therapy plus oesophagectomy has been accepted as the standard treatment for patients with potentially curable locally advanced oesophageal cancer. No completed randomized controlled trial (RCT) has directly compared neoadjuvant chemotherapy and neoadjuvant chemoradiation in patients with oesophageal squamous cell carcinoma (ESCC). The aim of the current RCT is to investigate the impact of neoadjuvant chemotherapy plus surgery and neoadjuvant chemoradiotherapy plus surgery on overall survival for patients with resectable locally advanced ESCC. METHODS: This open label, single-centre, phase III RCT randomized patients (cT2-T4aN + M0 and cT3-4aN0M0) in a 1:1 fashion to receive either the CROSS regimen (paclitaxel 50 mg/m2; carboplatin (area under the curve = 2), q1w, 5 cycles; and concurrent radiotherapy, 41.4 Gy/23 F, over 5 weeks) or neoadjuvant chemotherapy (paclitaxel 175 mg/m2; and cisplatin 75 mg/m2, q21d, 2 cycles). Assuming a 12% 5-year overall survival difference in favour of the CROSS regimen, 80% power with a two-sided alpha level of 0.05 and a 5% dropout each year for an estimated 3 years enrolment, the power calculation requires 456 patients to be recruited (228 in each group). The primary endpoint is 5-year overall survival, with a minimum 5-year follow-up. The secondary endpoints include 5-year disease-free survival, toxicity, pathological complete response rate, postoperative complications, postoperative mortality and quality of life. A biobank of pre-treatment and resected tumour tissue will be built for translational research in the future. DISCUSSION: This RCT directly compares a neoadjuvant chemotherapy regimen with a standard CROSS regimen in terms of overall survival for patients with locally advanced ESCC. The results of this RCT will provide an answer for the controversy regarding the survival benefits between the two treatment strategies. TRIAL REGISTRATION: NCT04138212, date of registration: October 24, 2019.

[Effect of Huaier aqueous extract on growth and metastasis of human non-small cell lung cancer NCI-H1299 cells and its underlying mechanisms].

This study aims to investigate the effect of Huaier aqueous extract on the growth and metastasis of human non-small cell lung cancer NCI-H1299 cells and its underlying mechanisms. MTT assay was used to detect the effect of Huaier aqueous extract on the proliferation of NCI-H1299 cells. Flow cytometry was used to examine the effect of Huaier aqueous extract on the apoptosis, cell cycle, and ROS level of NCI-H1299 cells. Wound healing assay was used to evaluate the effect of Huaier aqueous extract on the migration ability of NCI-H1299 cells. Western blot was used to detect the levels of proteins involving apoptosis, epithelial-mesenchymal transition(EMT), and MAPK signaling pathway in NCI-H1299 cells exposed to Huaier aqueous extract. The results showed that Huaier aqueous extract inhibited the proliferation of NCI-H1299 cells, and induced cell-cycle arrest at the phase S. Huaier aqueous extract promoted the apoptosis of NCI-H1299 cells by down-regulating the expression of anti-apoptotic protein Bcl-2. Moreover, Huaier aqueous extract increased ROS level and induced ferroptosis in NCI-H1299 cells. EMT played a critical role in cancer metastasis. Huaier aqueous extract reduced the migration ability of NCI-H1299 cells by inhibiting EMT of NCI-H1299 cells. In addition, this study revealed that Huaier aqueous extract inhibited MAPK signaling pathway in human non-small cell lung cancer NCI-H1299 cells, which may be one of Huaier's mechanisms in inhibiting growth and metastasis of NCI-H1299 cells. This study provides a new theoretical basis for the clinical treatment of lung cancer with Huaier, and important reference significance for further studies on the anti-tumor mechanisms of Huaier.

Tet methylcytosine dioxygenase 1 promotes hypoxic gene induction and cell migration in colon cancer.

Ten-eleven translocation 1 (TET1), a widely reported DNA demethylation protein, has been associated with tumorigenesis and metastasis. However, whether TET1 is an oncogene or tumor suppressor gene has been controversial; the mechanism of how TET1 affects cancer progression remains unclear. The current study aims to investigate how TET1 is changed in the tumor microenvironment and to explore the mechanisms of how TET1 affects colon cancer progression. Because hypoxia prevails on solid tumors, we established an important connection between hypoxia and DNA demethylation in tumorigenesis. By qPCR and RNA interference (RNAi) technology, we found that hypoxia increased TET1 expression with a hypoxia-inducible factor-1-alpha (HIF-1α)-dependent manner. By CHIP-qPCR and pyrosequencing technology, we demonstrated that TET1 regulated the target gene expression of HIF-1α through HIF-1α binding to hypoxia-responsive elements (HREs), and HIF-1α binding to HREs depended on CpG methylation levels. By Cell Counting Kit-8 (CCK-8) and transwell assay, we showed that loss of TET1 did not affect cell proliferation but inhibited migration. We also identified two novel gene mutants of TET1 in 120 paired tumor/normal tissue specimens by DNA sequencing and found that TET1 E2082K mutant blocked the TET1-enhanced cell migration. Our results showed that the downregulation of TET1 rescued the abnormally high levels of gene expression resulting from hypoxia in tumors and reduced the migration activity of tumor cells, suggesting a therapeutic role by interference with TET1 in colon cancer treatment. By demonstrating that hypoxia upregulated TET1 and that TET1 drove HIF-1α-responsive genes, we showed that an epigenetic mechanism and tumor microenvironment-driven models coexisted and mutually affected colon cancer.

Trim47 is a critical regulator of cerebral ischemia-reperfusion injury through regulating apoptosis and inflammation.

Cerebral ischemia is a leading cause of death and long-term disability in the world. Tripartite motif-47 (Trim47), a member of the TRIM family proteins, has been reported to be involved in apoptosis and inflammation in various types of diseases. Nevertheless, the underlying molecular mechanism of Trim47 in cerebral ischemia/reperfusion (I/R) injury remains unclear. This study aimed to explore the role of Trim47 in cerebral I/R injury and the potential underlying mechanisms. The results indicated that Trim47 expression was markedly induced in rats after stroke onset. By the use of genetic approaches, we indicated that Trim47 knockdown significantly reduced the infarct size, mitigated the neurological deficits scores and decreased brain water contents in rats with cerebral I/R injury induced by middle cerebral artery occlusion (MCAO). In addition, Trim47 knockdown-alleviated cerebral I/R was correlated with the suppression of apoptosis through inhibiting Caspase-3 cleavage. Furthermore, reducing Trim47 apparently decreased the release of pro-inflammatory factors, including interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS), in brain samples of MCAO rats, which was partly by the blockage of nuclear factor-kappa B (NF-κB) signaling. However, Trim47 over-expression markedly accelerated cerebral ischemia injury through promoting apoptosis and inflammation. The suppressive effects of Trim47 knockdown on cerebral I/R were verified in human neuron-like cells stimulated by oxygen and glucose deprivation (OGD). Thus, this study demonstrated a new mechanism for the effect of Trim47 on cerebral I/R injury, and targeting Trim47 might provide feasible therapies for stroke treatment.

Effect of inappropriate admissions on hospitalization performance in county hospitals: a cross-sectional study in rural China.

BACKGROUND: Inappropriate admissions cause excessive utilization of health services compared with outpatient services. However, it is still unclear whether inappropriate admissions cause excessive use of health services compared with appropriate admissions. This study aims to clarify the differences in the hospitalization performances between appropriately admitted inpatients and inappropriately admitted inpatients. METHODS: A total of 2575 medical records were obtained after cluster sampling in three counties. Admission appropriateness was assessed by appropriateness evaluation protocol (AEP). The propensity score matching (PSM) was computed to match patients in treatment and control group with similar characteristics, and to examine the differences in the utilization of hospitalization services between the two groups. The samples were matched in two major steps in this study. In the first step, total samples were matched to examine the differences in the utilization of hospital services between the two groups using 15 individual covariates. In the second step, PSM was computed to analyze the differences between the two groups in different disease systems using 14 individual covariates. RESULTS: For the whole sample, the inappropriate group has lower expenditure of hospitalization (EOH) (difference = - 0.12, p = 0.003) and shorter length of stay (LOS) (difference = - 0.73, p = 0.016) than the appropriate group. For number of clinical inspection (NCI), it has no statistically significant difference (difference = - 0.39, p = 0.082) between the two groups. Among different disease systems, no significant differences were observed between the two groups among EOH, LOS and NCI, except that the EOH was lower in the inappropriate group than that in the appropriate group for surgical disease (difference = - 0.169, p = 0.043). CONCLUSION: Inappropriate admissions have generated excessive health service utilization compared with appropriate admissions, especially for internal diseases. The departments in charge of medical services and hospital managers should pay high attention to the health service utilization of the inappropriately admitted inpatients. Relevant medical policies should be designed or optimized to increase the appropriateness in health care service delivery and precision in clinical pathway management.

Determinants of inappropriate admissions of children to county hospitals: a cross-sectional study from rural China.

BACKGROUND: The incidence of inappropriate admissions in China has become the shackle of its' service supply system. This research aims to assess the level of children's inappropriate admissions to county hospitals in rural China and identify the characteristics and determinants of children's inappropriate admissions. METHODS: A retrospective review was conducted on data of children aged 0-14 years. A total of 771 children medical records in four county hospitals was collected by stratified random sampling in Midwestern China and was evaluated through the Rural Appropriateness Evaluation Protocol. A questionnaire survey was conducted among doctors whose names were shown in medical records. Chi-square test was used to analyse the characteristics of inappropriate admissions, and a binary logistic regression model was used to examine the determinants of inappropriate admissions. RESULTS: Inappropriate admissions indicate that patients who could have been treated as outpatients received services as inpatients. The average rate for inappropriate admissions of children in county hospitals was 61.35%. The highest rate of inappropriate admissions was found among children aged 1-5 years (68.42%). Inappropriate admissions mostly occurred in children with respiratory diseases (72.45%), circulatory diseases (72.22%) and certain infectious diseases and parasitic diseases (70.37%). Binary logistic regression analysis showed that county, normal health status, treating department, disease, the length of hospital stay and the doctor's self-evaluation on the understanding about the degree of the patient's feelings were determinants for children's inappropriate admissions. CONCLUSIONS: County hospitals have a high rate of inappropriate admissions of children. The relationship of children's inappropriate admissions to age distribution and the insurance compensation is affected by disease and hospitalisation expenses, respectively. The determinants of children's inappropriate admissions are directly related to the weak level of primary care services in the health service system, the initial requirements requested by children's admission decision makers and the interests among medical institutions and doctors.

Effect of viscosity on pseudo-Scholte wave propagation at liquid/porous medium interface.

A theory of pseudo-Scholte wave propagating in a saturated porous medium loaded on its interface by a viscous compressible liquid is described. The porous medium is simulated by the Biot theory with high-frequency correction, and the overlying liquid is simulated by the linearized Navier-Stokes equation. An analytical expression for the complex dispersion equation of pseudo-Scholte wave through boundary conditions is established. Then the Riemann sheets related to body waves are discussed and the real and imaginary parts of the complex dispersion equation are separated and solved numerically. The resulting phase velocity, attenuation, as well as displacement and pressure fields are analyzed and comparisons are drawn with the non-viscous model. Finally, a set of parametric analyses is carried out to describe the effects of the phase velocity ratios of the S-wave in the porous medium to Ls-mode in overlying liquid on phase velocity and attenuation of the pseudo-Scholte waves.

Changes in inpatients' distribution and benefits under institution level-based quota payment for specific diseases in rural China: An interrupted time-series analysis.

The distribution of patients is increasingly disordered in China, which leads to the waste of medical resources, increase in inpatients' economic burden, and decrease in benefits from health insurance. Institution level-based quota payment for specific diseases represents a typical payment-system reform mode in rural China that rationalizes the distribution of rural inpatients. The aim of this study is to evaluate the effectiveness of this mode by estimating rural inpatients' distribution among hospitals at different levels, per capita cost of hospitalization, and actual compensation ratio and then to provide suggestions to advance this mode. Interrupted time-series analysis was applied to evaluate the effect of the reform mode in the study, and Weiyuan County, Gansu Province, was selected as our sample. Institution level-based quota payment for specific diseases in Weiyuan County has rationalized the distribution of rural inpatients and improved their benefit levels. Further research should be conducted to evaluate the appropriateness of medical services, the health outcomes of rural inpatients, and the sustainability and replicability of the policy.

KfoA, the UDP-glucose-4-epimerase of Escherichia coli strain O5:K4:H4, shows preference for acetylated substrates.

Capsule of Escherichia coli O5:K4:H4 is formed of a chondroitin-repeat disaccharide unit of glucuronic acid (GlcA)-N-acetylgalactosamine (GalNAc). This polysaccharide, commonly referred to as K4CP, is a potentially important source of precursors for chemoenzymatic or bioengineering synthesis of chondroitin sulfate. KfoA, encoded by a gene from region 2 of the K4 capsular gene cluster, shows high homology to the UDP-glucose-4-epimerase (GalE) from E. coli. KfoA is reputed to be responsible for uridine 5'-diphosphate-N-acetylgalactosamine (UDP-GalNAc) supply for K4CP biosynthesis in vivo, but it has not been biochemically characterized. Here, we probed the substrate specificity of KfoA by a capillary electrophoresis (CE)-based method. KfoA could epimerize both acetylated and non-acetylated substrates, but its k cat/K m value for UDP-GlcNAc was approximately 1300-fold that for UDP-Glc. Recombinant KfoA showed a strong preference for acetylated substrates in vitro. The conclusion that KfoA is a higher efficiency UDP-GalNAc provider than GalE was supported by a coupled assay developed based on the donor-acceptor combination specificity of E. coli K4 chondroitin polymerase (KfoC). Furthermore, residue Ser-301, located near the UDP-GlcNAc binding pocket, plays an important role in the determination of the conversion ratio of UDP-GlcNAc to UDP-GalNAc by KfoA. Our results deepen the understanding of the mechanism of KfoA and will assist in the research into the metabolic engineering for chondroitin sulfate production.

Identification and characterization of a chondroitin synthase from Avibacterium paragallinarum.

Avibacterium paragallinarum is a Gram-negative bacterium that causes infectious coryza in chicken. It was reported that the capsule polysaccharides extracted from Av. paragallinarum genotype A contained chondroitin. Chondroitin synthase of Av. paragallinarum (ApCS) encoded by one gene within the presumed capsule biosynthesis gene cluster exhibited considerable homology to identified bacterial chondroitin synthases. Herein, we report the identification and characterization of ApCS. This enzyme indeed displays chondroitin synthase activity involved in the biosynthesis of the capsule. ApCS is a bifunctional protein catalyzing the elongation of the chondroitin chain by alternatively transferring the glucuronic acid (GlcA) and N-acetyl-D-galactosamine (GalNAc) residues from their nucleotide forms to the non-reducing ends of the saccharide chains. GlcA with a para-nitrophenyl group (pNP) could serve as the acceptor for ApCS; this enzyme shows a stringent donor tolerance when the acceptor is as small as this monosaccharide. Then, UDP-GalNAc and GlcA-pNP were injected sequentially through the chip-immobilized chondroitin synthases, and the surface plasmon resonance data demonstrated that the up-regulated extent caused by the binding of the donor is one possibly essential factor in successful polymerization reaction. This conclusion will, therefore, enhance the understanding of the mode of action of glycosyltransferase. Surprisingly, high activity at near-zero temperature as well as weak temperature dependence of this novel bacterial chondroitin synthase indicate that ApCS was a cold-active enzyme. From all accounts, ApCS becomes the fourth known bacterial chondroitin synthase, and the potential applications in artificial chondroitin sulfate and glycosaminoglycan synthetic approaches make it an attractive glycosyltransferase for further investigation.

Dietary patterns and the risk of metabolic syndrome in Chinese adults: a population-based cross-sectional study.

OBJECTIVE: Data on dietary patterns in relation to the risk of metabolic syndrome (MetS) in a middle-aged Chinese population are sparse. The present study was performed to determine the major dietary patterns among a population aged 45-59 years and to evaluate their associations with MetS risk in China. DESIGN: Cross-sectional examination of the association between dietary patterns and MetS. Face-to-face interviews were used to assess dietary intake using a validated semi-quantitative FFQ. OR and 95 % CI for MetS were calculated across quartiles of dietary pattern scores using multivariate logistic regression analysis models. SETTING: City of Linyi, Shandong Province, China. SUBJECTS: Adults (n 1918) aged 45-59 years. RESULTS: Three major dietary patterns were identified: traditional Chinese, animal food and high-energy. After adjustment for potential confounders, individuals in the highest quartile of the traditional Chinese pattern had a reduced risk of MetS relative to the lowest quartile (OR=0·72, 95 % CI 0·596, 0·952; P<0·05). Compared with those in the lowest quartile, individuals in the highest quartile of the animal food pattern had a greater risk of MetS (OR=1·28; 95 % CI 1·103, 1·697; P<0·05). No significant association was observed between the high-energy pattern and risk of MetS. CONCLUSIONS: These findings indicate that the traditional Chinese pattern was associated with a reduced risk, while the animal food pattern was associated with increased risk of MetS. Given the cross-sectional nature of our study, further prospective studies are warranted to confirm these findings.