Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15  PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10  TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60  TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

[A case of giant pleural tuberculoma]

We retrospectively analyzed a rare case of giant pleural tuberculoma. The patient was a female, 62 years old, admitted to hospital for intermittent fever and hemoptysis. The CT scan of the chest and abdomen showed a mass in the right thoracic cavity, and the uneven surface of the bilateral fallopian tubes. Routine blood tests showed a decrease in platelets, white blood cells, and hemoglobin. The mass in the chest was finally confirmed as a tuberculoma by biopsy. The patient was diagnosed with tuberculosis more than 9 years ago and had been treated with anti-tuberculosis drugs for more than 9 years, which caused damage to the liver, bone marrow and other organs, and led to the drug-resistant tuberculosis, making diagnosis and treatment more complex.

[The value of nomogram for predicting microvascular invasion based on clinical and Gd-EOB-DTPA-enhanced magnetic resonance imaging features]

Objective: To investigate the risk factors of microvascular invasion (MVI) in China liver cancer staging system stage Ⅰa (CNLC Ⅰa) hepatocellular carcinoma (HCC), and develop a nomogram for predicting MVI based on clinical and radiographic data. Methods: This retrospective study focused on CNLC Ⅰa HCC patients who underwent radical resection at the Cancer Hospital, Chinese Academy of Medical Sciences from January 2016 to December 2020. Patients' clinical characteristics and laboratory test results and pre-surgery gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging results were collected. The clinical and radiographic risk factors for MVI were identified by univariate and multivariate logistic regression analyses and used for the construction of the predictive nomogram. The nomogram model was then internally validated, and its performance was assessed. Results: A total of 104 patients were divided into the MVI-positive group (n=28) and the MVI-negative group (n=76). Multivariate logistic regression analysis at the P<0.1 level identified serum alpha-ferroprotein >7 ng/ml, total bilirubin >21 μmol/L, prothrombin time >12.5 s, non-smooth margin, and incomplete or absent capsule as risk factors of MVI, based on which a nomogram model was built. The model achieved an area under the curve (AUC) value of 0.867 (95% confidence interval, 0.791-0.944) in the internal validation. The sensitivity and specificity of the nomogram model were 0.786 and 0.829, respectively, with the prediction curve nearly overlapping the ideal curve. Based on the Hosmer-Lemeshow test, the predicted and real results were not significantly different (P=0.956). Conclusions: The probability of MVI of CNLC Ⅰa HCC can be objectively predicted by the monogram model that quantifies the clinical and radiographic risk factors. The model can also help clinicians select individualized surgical plans to improve the long-term prognosis of patients.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory of the bright GRB 221009A, which serendipitously occurred within the instrument field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger, then rose to a peak about 10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

Factors associated with failure of high-flow nasal cannula oxygen therapy in patients with severe COVID-19: a retrospective case series

Objective

To identify factors associated with high-flow nasal cannula (HFNC) therapy failure in patients with severe COVID-19.

Methods

We retrospectively examined clinical and laboratory data upon admission, treatments, and outcomes of patients with severe COVID-19. Sequential Organ Failure Assessment (SOFA) scores were also calculated.

Results

Of 54 patients with severe COVID-19, HFNC therapy was successful in 28 (51.9%) and unsuccessful in 26 (48.1%). HFNC therapy failure was more common in patients aged ≥60 years and in men. Compared with patients with successful HFNC therapy, patients with HFNC therapy failure had higher percentages of fatigue, anorexia, and cardiovascular disease; a longer time from symptom onset to diagnosis; higher SOFA scores; a higher body temperature, respiratory rate, and heart rate; more complications, including acute respiratory distress syndrome, septic shock, myocardial damage, and acute kidney injury; a higher C-reactive protein concentration, neutrophil count, and prothrombin time; and a lower arterial partial pressure of oxygen/fraction of inspired oxygen (PaO₂/FiO₂). However, male sex, a low PaO₂/FiO₂, and a high SOFA score were the only independent factors significantly associated with HFNC therapy failure.

Conclusions

Male sex, a low PaO₂/FiO₂, and a high SOFA score were independently associated with HFNC therapy failure in patients with severe COVID-19.

[Associations between gene polymorphisms of signal transducer and activator of transcription 3 and the susceptibility to hepatitis B virus related liver cirrhosis]

To investigate the associations between gene polymorphisms of signal transducer and activator of transcription 3 (STAT3) and liver cirrhosis (LC) after hepatitis B virus (HBV) infection. A case-control study was conducted in 243 patients with hepatitis B cirrhosis (HBV-LC, case group) and 486 HBV-infected subjects without LC (non-LC, control group) collected from January 2018 to September 2020 at the Changsha Central Hospital Affiliated to Nanhua University. Three single nucleotide polymorphisms (SNPs) of STAT3 gene, including rs4796793C>G, rs2293152C>G, and rs1053004T>C were selected through literature and biological information database, and the genotypes were detected by real-time fluorescent quantitative PCR (RFQ-PCR). The distribution differences of STAT3 SNPs genotypes between the two groups were compared using Chi-square test and haplotype analysis was conducted by Shesis online. The proportion of HBV C genotype in HBV-LC patients was significantly higher than that in the control group (80.91% vs. 70.79%, χ²=7.109, P=0.008), while the logarithm of ALT was significantly lower than that of the control group (1.78±0.43 vs. 1.95±0.54, t=3.801, P=0.000). The genotypes distributions of rs4796793, rs2293152, and rs1053004 were not significantly different between HBV-LC and non-LC in overall analysis and stratified analysis by gender (χ²=2.610, 1.505, 0.586, 2.653, 2.685, 1.583, 0.351, 5.388, 0.339, respectively, P>0.05 for each). Among the subjects infected with HBV genotype C, rs1053004 CC (vs. TT) significantly increased the risk of HBV-LC [odds ratio (OR) = 1.40, 95% confidence interval (CI): 1.03-1.91]. Among the HBV-infected subjects with HBeAg negative, rs4796793 GG genotype (vs. CC) and G allele (vs. C) significantly increased the risks of HBV-LC (OR = 2.17, 95%CI: 1.11-4.23; OR = 1.45, 95%CI: 1.06-1.97, respectively). Haplotypes analysis showed that the frequency of haplotype C-G-T composed of rs4796793, rs2293152, and rs1053004 was significantly lower in HBV-LC than that in the control group (non-LC) (27.3% vs. 35.6%, χ²=9.949, P = 0.001). The correlation between STAT3 and HBV-LC is different in HBV-infected subjects with different infection status. The HBV-infected subjects carrying haplotype rs4796793C-rs2293152G-rs1053004T of STAT3 gene have significantly decreased risk of LC.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

[Correlation study between changes in intestinal microflora structure and immune indexes in newly treated patients with pulmonary tuberculosis]

To explore the correlation between the changes of the intestinal flora of newly treated pulmonary tuberculosis patients and the immune indicators of the body, and to provide a reference for the prevention and treatment of pulmonary tuberculosis. A single-center and case-control study was adopted. From October 2020 to April 2021, 43 patients with newly diagnosed tuberculosis in the Department of Tuberculosis, Affiliated Changsha Central Hospital,University of South China were selected as the control group. 43 cases of newly treated pulmonary tuberculosis (PTB), 43 healthy control (HC) during the same period, collected fresh feces and whole blood of subjects, and used Illumina Hiseq high-throughput sequencing technology to analyze 16S of all microorganisms in feces The V4 region of rRNA was amplified and sequenced, and the structure of the intestinal flora was analyzed by QIIME software. Use flow cytometry to determine the subject's immune indicators (CD3⁺, CD4⁺, CD8⁺, CD4⁺CD25⁺CD127^-Treg, CD14⁺CD16⁺, CD14⁺CD16^-), and analyze the changes in intestinal flora and immune function in newly treated pulmonary tuberculosis patients Inherent connection. The χ² test, t test, and Wilcox rank sum test were used to analyze the differences in age, gender, α diversity, and relative abundance of the two groups of people. Compared with the HC group, the alpha diversity of the intestinal flora in the PTB group decreased (shannon index: t=3.906, P=0.000 2; simpson index: Z=553, P=0.004 7; chao1 index: t=5.395, P=0.000 0). β diversity analysis showed that there were significant differences in the structure of the intestinal flora between the two groups (P=0.000). Species difference analysis showed that at the phylum level, the relative abundance of Firmicutes in the PTB group was significantly lower than that in the HC group (Z=486.0, P=0.000 5). At the genus level, there are 15 different bacterial genera between the two groups. In the PTB group, bifidobacterium, enterococcus, lactobacillus, anaerostipes, the relative abundance of the above 5 genera of veillonella is higher than that of the HC group (P<0.05); Butyricimonas, clostridium, and broutella (blautia), coprococcus, dorea, lachnospira, roseburia, faecalibacterium, ruminococcus, the relative abundance of 10 bacterial genera including dialister was lower than that of the HC group (P<0.05). Comparison of immune indexes between groups showed that CD14⁺CD16⁺monocytes (%) in the PTB group were higher than those in the HC group (t=2.456, P=0.001 6<0.05), while CD14⁺CD16^-monocytes (%) were lower than HC (t=-4.368, P=0.000<0.05), while the differences in CD3⁺, CD4⁺, CD8⁺, CD4⁺/CD8⁺and Treg (CD4⁺CD25⁺CD127^-) were not statistically significant (P>0.05). Spearman correlation analysis showed that Firmicutes in the PTB group was negatively correlated with CD4⁺/CD8⁺, CD14⁺CD16⁺(r=-0.218, P=0.048; r=-0.245, P=0.025), and positively correlated with CD14⁺CD16^-Correlation (r=0.250, P=0.022); At the genus level, Faecalis is positively correlated with CD4⁺/CD8⁺and CD4⁺(r=0.250, P=0.023; r=0.258, P=0.019); Rosella and CD3⁺, CD8⁺and CD14⁺CD16^-are positively correlated (r=0.27, P=0.024; r=0.219, P=0.046; r=0.027, P=0.039), and negatively correlated with CD14⁺CD16⁺(r=-0.280, P= 0.01). Changes in the structure of the intestinal flora of newly treated pulmonary tuberculosis patients may be one of the influencing factors of the immune function of the body. Targeted optimization of the structure of the intestinal flora and improvement of the body's immunity may be used as an effective auxiliary treatment for pulmonary tuberculosis.

[Efficacy and safety of paclitaxel liposomes compared to paclitaxel combined with platinum in concurrent chemoradiotherapy for unresectable cervical carcinoma: a Meta-analysis]

Objective: To explore the efficacy and safety of paclitaxel liposomes compared to paclitaxel with platinum in concurrent chemoradiotherapy for unresectable cervical carcinoma. Methods: SinoMed, CNKI, WanFang MED ONLINE, VIP, PubMed, MEDLINE, Cochrane Library, Embase and ClinicalTrials.gov were searched to collect the papers or clinical studies of paclitaxel liposomes and paclitaxel combined with platinum in concurrent chemoradiotherapy for unresectable cervical carcinoma from the inception to January 15th 2021 in Chinese and English. Two independent reviewers screened the literatures, extracted the data and assessed the bias of the included studies. Meta-analysis was performed using RevMan 5.4 and R software. Results: Totally 9 papers involving 666 patients with unresectable cervical carcinoma were included. The results of meta-analysis indicated that compared to paclitaxel combined with platinum in concurrent chemoradiotherapy for unresectable cervical carcinoma, paclitaxel liposomes combined with platinum exhibited superiority in near-term efficacy (complete response + partial response) [81.4%(272/334) vs 68.7%(228/332), RR=1.19; 95% CI: 1.09, 1.29, P=0.000 1]; substantially decreased the incidence rates of blood system disorders [myelosuppressio, 50.3%(168/334)vs 65.1%(216/332)], gastrointestinal disorders [34.4%(115/334) vs 55.1%(183/332)], alopecia [42.2%(94/223)vs 63.3%(140/221)], allergic reaction [11.6% (23/198)vs 27.6%(54/196), P≤0.000 1], peripheral neuritis [43.0%(52/121) vs 54.9%(67/122)], or joint and muscle pain [20.3%(16/79) vs 34.6%(28/81), P<0.050 0]. Conclusion: Compared to paclitaxel combined with platinum in concurrent chemoradiotherapy for unresectable cervical carcinoma, paclitaxel liposomes is superior in near-term efficacy, and exhibits better safety.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

[Value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid enhanced magnetic resonance imaging and diffusion-weighted MR imaging in predicting microvascular invasion in hepatocellular carcinoma and the prognostic significance]

Objective: To investigate the combined value of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) enhanced magnetic resonance imaging (MRI) and diffusion-weighted imaging (DWI) in predicting pathological microvascular invasion (pMVI) preoperatively, and to determine the relationship between prediction results and prognosis in hepatocellular carcinoma (HCC) patients. Methods: A total of 181 newly diagnosed HCC patients were enrolled in this study. Imaging characteristics and the apparent diffusion coefficient (ADC) value of DWI were analyzed. The differences of imaging characteristics and ADC values between different pMVI groups were analyzed.Multivariate logistic regression and receiver operating characteristic (ROC) curve were used to analyze the value for pMVI prediction by using significant parameters. The patients were grouped based on MRI predicted MVI (mrMVI), and the relationship between mrMVI and recurrence free survival time (RFS) was analyzed. Results: Fifty-one patients were pMVI positive and 130 patients were pMVI negative. The ADC value in pMVI positive group were (1.10±0.17)×10(-3) mm(2)/s, significantly lower than (1.27±0.22)×10(-3) mm(2)/s of pEMVI negative group (P<0.001). The incidence rates of incomplete enhancing "capsule" , non-smooth tumor margin, arterial peritumoral enhancement, mosaic architecture and peritumoral hypointensity on hepatobiliary phase (HBP) in pMVI positive group were significantly higher than those of negative group (all P<0.05). Multivariate logistic regression analysis showed that tumor margin, arterial peritumoral enhancement, peritumoral hypointensity on HBP and ADC value were independently associated with pMVI. ROC analysis showed that the area under curve, sensitivity and specificity of pMVI predicted by combined parameters were 0.830, 76.5% and 81.5%, respectively. The median RFS of mrMVI positive group was 23.6 months, significantly lower than 38.2 months of mrEMVI negative group (P=0.004). Conclusion: Tumor margin, arterial peritumoral enhancement, peritumoral hypointensity on HBP and ADC value are independent predictors of pMVI in HCC, and mrMVI is related with RFS.

[Study on the relationship between serum vitamin D and the risk of type 2 diabetes in Harbin residents]

Objective: To analyze the relationship between serum vitamin D level and the risk of type 2 diabetes in Harbin residents. Methods: On April 2010, 24 communities in 7 districts of Harbin were selected as research sites using multi-stage stratified cluster random sampling method. A total of 9 734 residents aged 20-74 years was investigated using general questionnaire survey, dietary survey and biochemical indicators test and followed up from January 2015 to July 2016. A total of 4 721 subjects with serum vitamin D were included in the study. According to the quartile of baseline serum vitamin D, the subjects were divided into four groups, from Q1 to Q4 group. The multivariate logistic regression model was used to analyze the relationship between serum vitamin D and the risk of type 2 diabetes. A mediation analysis model was used to analyze the mediating role of insulin resistance in this risk relationship. Results: At the time of follow-up, 432 patients with type 2 diabetes were screened. The median (P(25), P(75)) age of the diabetic group and the non-diabetic group were 54 (49, 61) and 51 (43, 57) years, respectively, and males accounted for 40.5% (175 cases) and 35.5% (1 513 cases), respectively. The median (P(25), P(75)) serum vitamin D was 16.0 (13.5, 18.5) and 17.4 (14.3, 20.5) ng/ml, respectively. After relevant confounders and insulin resistance index (HOMA-IR) were adjusted, compared to the serum vitamin D level Q(1) group, the risk of diabetes was reduced by 40% in the Q(3) group with RR (95%CI) about 0.60 (0.44-0.82), while the risk of diabetes was reduced by 59% in Q(4) group with RR (95%CI) about 0.41 (0.29-0.57). Through mediation analysis, the Gutt index mediating effect representing peripheral insulin resistance was 53.8%, and the mediating effect of HOMA-IR representing hepatic insulin resistance was 6.6%. Conclusion: The risk of type 2 diabetes is low in Harbin residents with higher serum vitamin D level. Insulin resistance has a mediating effect on the relationship of vitamin D and the risk of type 2 diabetes.

[Association between dyslipidemia and carotid plaque incidence in a research group: a prospective cohort study]

Objective: To assess the association and intensity of baseline dyslipidemia with the incidence of carotid plaque in a researchers group in China. Methods: A total of 716 researchers were enrolled in this prospective cohort study. Dyslipidemia was assessed in 2010. Follow-up study on carotid plaque was conducted in 2017. Results: Over 8 years' follow-up, 289 carotid plaque patients were identified among 716 individuals who did not have carotid plaque at baseline survey, with cumulative incidence of 40.36%. After adjustment of age, gender, BMI, waist circumference, FPG, SBP, DBP, ALT and uric acid, compared with non-dyslipidemia group, HR of carotid plaque for such populations with ≥3 types of dyslipidemia was 1.681 (95%CI: 1.090--2.593). Conclusions: Dyslipidemia might be associated with higher risk of carotid plaque, and population with ≥3 types of dyslipidemia had higher risk for carotid plaque. Prevention of dyslipidemia or reduction of types of dyslipidemia might be one of the effective precautions for prevention of carotid plaque.

[Research of mHLA-G and the receptor expression with kidney rejection and CMV active infection following kidney transplantation]

Objective: To study the expression of membrane HLA-G (mHLA-G) and the receptor immunoglobulin-like transcript 2(ILT2) on lymphocyte and find their association with rejection and cytomegalovirus (CMV) infection after renal transplantation. Methods: A total of 88 cases of renal transplant recipients for the first time from February 2014 to February 2016 were studied in this work. Recipients can be divided into rejection group (n=12) and stable renal function group (n=41) according to whether rejection occurred. Recipients only infected CMV not developed rejection were included in the CMV positive group (n=24). CMV negative group (n=11) including CMV negative recipients once infected CMV.The expression of mHLA-G and ILT2 on lymphocytes were detected by flow cytometry, and the differences among different groups were analyzed. Results: The data showed that after renal transplantation, T and B lymphocytes mHLA-G expression rate was the lowest in the rejection group (0.42%±0.35%, 0.88%±0.47%), having significant difference with renal function stable group and CMV positive group (all P<0.01). In CMV positive group the expression of mHLA-G on T and B lymphocytes was the highest (1.31%±0.69%, 2.01%±0.91%), having significant difference with rejection group (P<0.001). The expression of mHLA-G on B cell was statistically significantly different between CMV positive group and CMV negative group (P<0.05). There was no significant difference in ILT2 expression on B cell among the four groups (P>0.05). The expression rate of ILT2 on T cells was higher in the CMV positive group (36.91%±14.91%), having significant difference with the other three groups (P<0.01). Conclusions: Low expression of mHLA-G on T and B lymphocytes may predict rejection after renal transplantation. High expression of mHLA-G and ILT2 on lymphocytes is prone to CMV infection after renal transplantation .

[Effect of Human Umbilical Cord-derived Mesenchymal Stem Cells on Proliferation and Differentiation of Leukemia Cells]

OBJECTIVE

To investigate the effect of human umbilical cord-derived mesenchymal stem cells(HUC-MSC) on the proliferation and differentiation of NB4 treated with all-trans retinoid acid (ATRA) and its underlining mechanisms .

METHODS

Human umbilical cord mesenchymal stem cells were isolated from umbilical cord of newborns. Co-culture system was established by HUC-MSC and NB4 in vitro. The experiment was divided into 4 groups: NB4 group (NB4 cells alone) , NM group (NB4 cells co-cultured with HUC-MSC) , NA group (NB4 cells treated with ATRA) , NMA group (NB4 cells co-cultured with HUC-MSC and treated with ATRA) . NB4 cells were counted by a microscopy, NB4 proliferation was monitored by CCK-8 assay, NB4 differentiation was assessed by Wright ' s staining and nitroblue tetrazolium reduction test. IL-6 levels in the culture supernatant of different groups were tested by ELISA kit. Quantitative PCR was used to detect the transcription level of CDKN1A, CCND1 and Survivin.

RESULTS

NB4 and HUC-MSC in the co-culturing systems were in good condition with a slight repression of NB4 proliferation by HUC-MSC. HUC-MSC could collaborate with ATRA to induce significant NB4 differentiation. Consistent with this finding, IL-6 expression levels of co-cultured groups were remarkably higher than that in any other groups or the group of HUC-MSC alone. The quantitative PCR analysis showed that the levels of CDKN1A and CCND1 mRNA expression were increased or decreased respectively in the co-cultured groups.

CONCLUSION

HUC-MSC co-culture can reduce proliferation but promote the differentiation of NB4 cells, suggesting that this effect may be closely related with the secretion of IL-6 which can affect the expression of some factors in vitro.

[Characteristics of HBV transmission in families with HBsAg-positive fathers and familial clustering of HBV infection]

OBJECTIVE

To investigate the characteristics of hepatitis B virus (HBV) transmission among family members in families with familial clustering of HBV infection and poor outcomes, as well as the prevalence and distribution characteristics of HBsAg in offspring with different parental HBsAg status.

METHODS

The general information of each member in families with poor outcomes were collected from 2007 to 2010, and serological test was performed to analyze the prevalence and distribution of HBsAg in family members. The chi-square test or Fisher's exact test was used to analyze and compare the sex of offspring and the prevalence of HBsAg in them in 266 nuclear families with different paternal and maternal HBsAg status.

RESULTS

The positive rates of HBsAg in parents, siblings, children, and spouses of the probands were 20%, 88.2%, 76.8%, and 9.5%, respectively. The nuclear families with HBsAg-positive fathers and HBsAg-negative mothers had a significantly increased proportion of male offspring (male/female ratio = 2.02) compared with those with HBsAg-positive mothers and HBsAg-negative fathers (1.22) or those with HBsAg-negative fathers and mothers (0.96). In addition, in the nuclear families with HBsAg-positive fathers and HBsAg-negative mothers, the male offspring had a significantly higher HBsAg positive rate than female offspring (37.4% vs 13.8%), while in those with HBsAg-positive mothers and HBsAg-negative fathers or those with HBsAg-negative fathers and mothers, HBsAg positive rate showed no significant difference between male and female offspring.

CONCLUSION

In families with familial clustering of HBV infection and poor outcomes, mother-to-child transmission is still the major route of HBV transmission, but father-to-child transmission also plays a role in HBV transmission in this special population. Positive HBsAg in fathers is associated with the increased proportion of male offspring, and father-to-son transmission of HBV is higher than father-to-daughter transmission.

[Effect of BD Regimen Combined with Cyclophosphamide and Pirarubicin in Treatment of Relapse/Refractory Multiple Myeloma]

OBJECTIVE

To compare the efficacy and safety of BD regimen combined with cyclophosphamide(CTX) and pirarubicin chemotherapy(P-CAD) for patients with relapse/refractory multiple myeloma(MM).

METHODS

Twenty-eight cases of relapse/refractory MM were enrolled in a group of P-CAD regimen, 36 cases of relapse/retractory MM treated with BD were used as controls. The therapeutic efficacy and adverse reactions of 2 regimens for patients with relapse/retractory MM were compared and analyzed.

RESULTS

The overall response rate (CR+NCR+PR+MR) of the 28 cases treated with P-CAD regimen was 85.7%, and the response rate (CR+PR) was 75.0%. The median progression-free survival time were 16.1 months, and the average survival time were 30.6 months, while the overall response rate of the 36 patients treated with BD regimen was 63.9%, and the response rate was 55.6%. The median progression-free survival time were 13.7 months, and the average survival time were 26.7 months. The adverse reactions of 2 groups included gastrointestinal reactions, peripheral neuropathy, fatigue, skin rashes, leucopenia and thrombocytopenia, and they were all well tolerated.

CONCLUSION

BD regimen combined with cyclophosphamide and pirarubicin chemotherapy can improve the response rate of patients with relapse/refractory multiple myeloma, and shows the trend of prolonging PFS and survival times. Patients were well tolerated, and this regimen is a new choice in treatment of relapse/refractory MM.

[Reconstruct abdominal aortic branch arteries totally by endovascular repair in complex aortic aneurysms: a single-centre experience]

OBJECTIVE

To report experiences and results of complex aortic aneurysms involving the visceral arteries treating by total endovascular repair.

METHODS

Seventy cases of thoracoabdominal aortic lesions treating by total endovascular repair in Department of Vascular Surgery, People's Liberation Army General Hospital from January 2011 to December 2014 were retrospectively analyzed. There were 47 cases underwent chimney technique, 6 underwent sandwich technique, 15 underwent fenestration technique and 2 underwent branched stent grafts technique.

RESULTS

The average follow-up time was 21 months, range from 3 to 47 months. Completion angiography showed that typeⅠ endoleak of chimney, sandwich, fenestration and branched stent grafts group were 9/47, 5/6, 2/15 and 0, respectively. While at 30-day typeⅠ endoleak reduced to 7/47, 2/6, 0 and 0. During follow-up, there were 3 target vessel stents occlusion in chimney group, the patency rate of target vessel stent was 95.1% (58/61). In sandwich, fenestration and branched stent grafts group, all the target vessel stents kept patent.

CONCLUSION

In this study, chimney, sandwich, fenestration and branched stent grafts techniques show good short-term and midterm results, the long-term effects still need further studies.

Effect of baculovirus P35 protein on apoptosis in brain tissue of rats with acute cerebral infarction

We explored the effect of baculovirus P35 protein on apoptosis in the brain tissue of rats with acute cerebral infarction (ACI). A rat model of middle cerebral artery infarction was created. The rats were randomly divided into sham, model, and treatment groups. Baculovirus P35 protein was injected into the intracranial arteries of the treatment group rats. The rats in the model group were given an equal volume of phosphate-buffered saline. The rats were sacrificed after 72 h and the brain tissue was separated. The levels of caspase-3, Bcl-2, and Bax mRNA, the brain cell apoptosis index, and the infarct size were determined. After 72 h, the levels of caspase-3 and Bax mRNA in the model and treatment groups were significantly greater than in the sham group, and the levels of Bcl-2 mRNA were significantly smaller (P < 0.05). The levels of caspase-3 and Bax mRNA were significantly lower in the treatment group than in the model group, and the level of Bcl-2 mRNA was significantly greater (P < 0.05). Compared with the sham group, the brain tissue apoptosis index and the cerebral infarction area increased significantly in the model and treatment groups (P < 0.05). The brain tissue apoptosis index and cerebral infarction area in the treatment group were significantly lower than in the model group (P < 0.05). Baculovirus P35 protein can effectively inhibit brain cell apoptosis in rats with ACI. It delayed apoptosis and necrosis in subjects with ACI tissue and had a protective effect on brain tissue.

Effect of surface free energies on the heterogeneous nucleation of water droplet: a molecular dynamics simulation approach

Heterogeneous nucleation of water droplet on surfaces with different solid-liquid interaction intensities is investigated by molecular dynamics simulation. The interaction potentials between surface atoms and vapor molecules are adjusted to obtain various surface free energies, and the nucleation process and wetting state of nuclei on surfaces are investigated. The results indicate that near-constant contact angles are already established for nano-scale nuclei on various surfaces, with the contact angle decreasing with solid-liquid interaction intensities linearly. Meanwhile, noticeable fluctuation of vapor-liquid interfaces can be observed for the nuclei that deposited on surfaces, which is caused by the asymmetric forces from vapor molecules. The formation and growth rate of nuclei are increasing with the solid-liquid interaction intensities. For low energy surface, the attraction of surface atoms to water molecules is comparably weak, and the pre-existing clusters can depart from the surface and enter into the bulk vapor phase. The distribution of clusters within the bulk vapor phase becomes competitive as compared with that absorbed on surface. For moderate energy surfaces, heterogeneous nucleation predominates and the formation of clusters within bulk vapor phase is suppressed. The effect of high energy particles that embedded in low energy surface is also discussed under the same simulation system. The nucleation preferably initiates on the high energy particles, and the clusters that formed on the heterogeneous particles are trapped around their original positions instead of migrating around as that observed on smooth surfaces. This feature makes it possible for the heterogeneous particles to act as fixed nucleation sites, and simulation results also suggest that the number of nuclei increases monotonously with the number of high energy particles. The growth of nuclei on high energy particles can be divided into three sub-stages, beginning with the formation of a wet-spot, increase of contact angle with near-constant contact line, and finally growth with constant contact angle. The growth rate of nuclei also increases with the size of high energy particles.

Polymorphisms in the delta-like 2 homolog gene and their association with growth and meat-quality traits in Qinchuan cattle

The delta-like 2 homolog (DLK2) modulates adipogenesis, hematopoiesis, osteogenesis, and other cell-differentiation processes. In the present study, we detected potential polymorphisms in the DLK2 gene in 604 individuals of Qinchuan cattle by using PCR-RFLP and DNA-sequencing methods. Herein, we identified five novel single-nucleotide polymorphisms (SNPs) (g.888G>A, g.910A>G, g.995G>A, g.4321A>G, g.4850A>G) and analyzed their association with measured traits. Four of the five analyzed polymorphisms were associated with at least one of the following traits: body weight (BW), chest depth (CD), chest circumference (CC), back fat thickness (BT), and rib-eye area (REA). To the best of our knowledge, our research is the first to report the association of DLK2 gene polymorphisms with growth and meat quality traits in Qinchuan cattle. In summary, the results of our study suggest that the DLK2 gene can be used as a candidate gene in beef cattle breeding.

Predicting targeted polypharmacology for drug repositioning and multi- target drug discovery

Prediction of polypharmacology of known drugs and new molecules against selected multiple targets is highly useful for finding new therapeutic applications of existing drugs (drug repositioning) and for discovering multi-target drugs with improved therapeutic efficacies by collective regulations of primary therapeutic targets, compensatory signalling and drug resistance mechanisms. In this review, we describe recent progresses in exploration of in-silico methods for predicting polypharmacology of known drugs and new molecules by means of structure-based (molecular docking, binding- site structural similarity, receptor-based pharmacophore searching), expression-based (expression profile/signature similarity disease-drug and drug-drug networks), ligand-based (similarity searching, side-effect similarity, QSAR, machine learning), and fragment-based approaches that have shown promising potential in facilitating drug repositioning and the discovery of multi-target drugs.

Virtual screening methods as tools for drug lead discovery from large chemical libraries

Virtual screening methods have been developed and explored as useful tools for searching drug lead compounds from chemical libraries, including large libraries that have become publically available. In this review, we discussed the new developments in exploring virtual screening methods for enhanced performance in searching large chemical libraries, their applications in screening libraries of ~ 1 million or more compounds in the last five years, the difficulties in their applications, and the strategies for further improving these methods.

SNPs at 3'-UTR of the bovine CDIPT gene associated with Qinchuan cattle meat quality traits

The CDIPT is crucial to the fatty acid metabolic pathway, intracellular signal transduction and energy metabolism in eukaryotic cells. We detected three SNPs at 3'-untranslated regions (UTR), named 3'-UTR_108 A > G, 3'-UTR_448 G > A and 3'-UTR_477 C > G, of the CDIPT gene in 618 Qinchuan cattle using PCR-RFLP and DNA sequencing methods. At each of the three SNPs, we found three genotypes named as follows: AA, AB, BB (3'-UTR_108 A > G), CC, CD, DD (3'-UTR_448 G > A) and EE, EF, FF (3'-UTR_477 C > G.). Based on association analysis of these SNPs with ultrasound measurement traits, individuals of genotype BB had a significantly larger loin muscle area than genotype AA. Individuals of genotype CC had significantly thicker back fat than individuals of genotype DD. Individuals of genotype EE also had significantly thicker back fat than did individuals of genotype FF. We conclude that these SNPs of the CDIPT gene could be used as molecular markers for selecting and breeding beef cattle with superior body traits, depending on breeding goals.

Novel SNPs in the exon region of bovine DKK4 gene and their association with body measurement traits in Qinchuan cattle

The aim of this study was to determine whether single nucleotide polymorphisms (SNPs) of bovine Dickkopf homolog 4 (DKK4) are associated with body measurement traits in Qinchuan cattle. By using PCR-SSCP technology and DNA sequencing, we discovered 5 DKK4 SNPs in Qingchuan cattle, including -65G>A and -77G>T in the 5'-untranslated region, 1532C>G and 1533T>C in exon 2, and 2088C>T in exon 3. The sequencing map showed that 1532C>G and 1533T>C were in close linkage disequilibrium and were treated as 1532C>G-1533T>C in this study. Allele frequencies were calculated and analyzed by the chi-square test, which showed that -65G>A and 1532C>G-1533T>C were in Hardy-Weinberg equilibrium (P > 0.05), whereas -77G>T and 2088C>T were not in all 633 tested Qinchuan cattle individuals (P < 0.01). Gene heterozygosity (HE), effective allele number (NE), and polymorphism information content (PIC) were 0.407, 1.686, and 0.324 at -65G>A; 0.472, 1.894, and 0.361 at -77G>T; 0.476, 1.908, and 0.363 at 1532C>G-1533T>C; and 0.218, 1.279, and 0.195 at 2088C>T. We also evaluated the potential association of these SNPs with body measurement traits in all 633 individuals; the results suggest that several SNPs in Qinchuan cattle DKK4 were significantly associated with body length, hip height, rump length, hip width, heart girth, and pin bone width (P < 0.05 and P < 0.01). These results suggest that bovine DKK4 could be used as candidate gene for Qinchuan cattle breeding.

Diabetes mellitus and incidence and mortality of gastric cancer: a meta-analysis

AIMS

Epidemiologic studies have examined the possible associations between diabetes mellitus (DM) and gastric cancer (GC), but the results are inconclusive. We conducted a meta-analysis to assess the evidence regarding the associations between diabetes and incidences of, or mortality from, gastric cancer.

METHODS

PubMed, Embase and Web of Science were searched up to Oct 20, 2011. We identified studies that included effects estimates with 95% confidence intervals (CIs) of the associations between GC and diabetes. Summary RRs for the GC incidence and mortality were calculated using random-effects model; subgroup analyses were also performed. Heterogeneity among studies was examined using Q and I2 statistics.

RESULTS

A total of 7 case-control and 18 cohort studies met the inclusion criteria. The summary RR showed a slightly statistical link between history of DM and GC incidence (RR=1.11, 95% CI: 1.00-1.24, p=0.045, I2=79.5%). In the subgroup analyses, a positive association was noted among the studies conducted in Asia (summary RR=1.19, 95% CI: 1.07-1.32, I2=29.8%). Additionally, slight associations between DM and GC were observed by pooling the data of type 2 DM, cohort studies and the studies controlling more confounders, respectively. Furthermore, mortality from GC with diabetes was increased compared with individuals without diabetes (summary RR=1.29, 95% CI: 1.04-1.59). No publication bias was found.

CONCLUSION

Individuals with diabetes have an increased risk of developing gastric cancer, and are positively associated with gastric cancer mortality. Large better-designed cohort studies are needed to verify this conclusion.

Effect of various freezing solutions on cryopreservation of mesenchymal stem cells from different animal species

The objective of this study is to compare the effects of different well defined freezing solutions with a reduced concentration of dimethylsulfoxide (DMSO) combined with polyethylene glycol (PEG) and/or trehalose on cryopreservation of mesenchymal stem cells (MSCs) from mice, rats and calves. Post-thaw cell viability, proliferation capacity and differentiation potential of MSCs from different species were assessed after cryopreservation with the conventional slow freezing method. Although the post-thaw viabilities and metabolic activities varied among the different species, satisfactory results were obtained with 5 percent (v/v) DMSO, 2 percent (w/v) PEG, 3 percent (w/v) trehalose and 2 percent (w/v) bovine serum albumin (BSA) as the freezing solution. Our results showed that mouse MSCs were more robust to cryopreservation compared with rat and bovine MSCs.

Virtual screening of selective multitarget kinase inhibitors by combinatorial support vector machines

Multitarget agents have been increasingly explored for enhancing efficacy and reducing countertarget activities and toxicities. Efficient virtual screening (VS) tools for searching selective multitarget agents are desired. Combinatorial support vector machines (C-SVM) were tested as VS tools for searching dual-inhibitors of 11 combinations of 9 anticancer kinase targets (EGFR, VEGFR, PDGFR, Src, FGFR, Lck, CDK1, CDK2, GSK3). C-SVM trained on 233-1,316 non-dual-inhibitors correctly identified 26.8%-57.3% (majority >36%) of the 56-230 intra-kinase-group dual-inhibitors (equivalent to the 50-70% yields of two independent individual target VS tools), and 12.2% of the 41 inter-kinase-group dual-inhibitors. C-SVM were fairly selective in misidentifying as dual-inhibitors 3.7%-48.1% (majority <20%) of the 233-1,316 non-dual-inhibitors of the same kinase pairs and 0.98%-4.77% of the 3,971-5,180 inhibitors of other kinases. C-SVM produced low false-hit rates in misidentifying as dual-inhibitors 1,746-4,817 (0.013%-0.036%) of the 13.56 M PubChem compounds, 12-175 (0.007%-0.104%) of the 168 K MDDR compounds, and 0-84 (0.0%-2.9%) of the 19,495-38,483 MDDR compounds similar to the known dual-inhibitors. C-SVM was compared to other VS methods Surflex-Dock, DOCK Blaster, kNN and PNN against the same sets of kinase inhibitors and the full set or subset of the 1.02 M Zinc clean-leads data set. C-SVM produced comparable dual-inhibitor yields, slightly better false-hit rates for kinase inhibitors, and significantly lower false-hit rates for the Zinc clean-leads data set. Combinatorial SVM showed promising potential for searching selective multitarget agents against intra-kinase-group kinases without explicit knowledge of multitarget agents.

Identifying Novel Type ZBGs and Nonhydroxamate HDAC Inhibitors Through a SVM Based Virtual Screening Approach

Histone deacetylase inhibitors (HDACi) have been successfully used for the treatment of cancers and other diseases. Search for novel type ZBGs and development of non-hydroxamate HDACi has become a focus in current research. To complement this, it is desirable to explore a virtual screening (VS) tool capable of identifying different types of potential inhibitors from large compound libraries with high yields and low false-hit rates similar to HTS. This work explored the use of support vector machines (SVM) combined with our newly developed putative non-inhibitor generation method as such a tool. SVM trained by 702 pre-2008 hydroxamate HDACi and 64334 putative non-HDACi showed good yields and low false-hit rates in cross-validation test and independent test using 220 diverse types of HDACi reported since 2008. The SVM hit rates in scanning 13.56 M PubChem and 168K MDDR compounds are comparable to HTS rates. Further structural analysis of SVM virtual hits suggests its potential for identification of non-hydroxamate HDACi. From this analysis, a series of novel ZBG and cap groups were proposed for HDACi design.

Virtual screening of Abl inhibitors from large compound libraries by support vector machines

Abl promotes cancers by regulating cell morphogenesis, motility, growth, and survival. Successes of several marketed and clinical trial Abl inhibitors against leukemia and other cancers and appearances of reduced efficacies and drug resistances have led to significant interest in and efforts for developing new Abl inhibitors. In silico methods of pharmacophore, fragment, and molecular docking have been used in some of these efforts. It is desirable to explore other in silico methods capable of searching large compound libraries at high yields and reduced false-hit rates. We evaluated support vector machines (SVM) as a virtual screening tool for searching Abl inhibitors from large compound libraries. SVM trained and tested by 708 inhibitors and 65,494 putative noninhibitors correctly identified 84.4 to 92.3% inhibitors and 99.96 to 99.99% noninhibitors in 5-fold cross validation studies. SVM trained by 708 pre-2008 inhibitors and 65 494 putative noninhibitors correctly identified 50.5% of the 91 inhibitors reported since 2008 and predicted as inhibitors 29,072 (0.21%) of 13.56M PubChem, 659 (0.39%) of 168K MDDR, and 330 (5.0%) of 6638 MDDR compounds similar to the known inhibitors. SVM showed comparable yields and substantially reduced false-hit rates against two similarity based and another machine learning VS methods based on the same training and testing data sets and molecular descriptors. These suggest that SVM is capable of searching Abl inhibitors from large compound libraries at low false-hit rates.

Prediction of antibiotic resistance proteins from sequence-derived properties irrespective of sequence similarity

Increasing antibiotic resistance has become a worldwide challenge to the clinical treatment of infectious diseases. The identification of antibiotic resistance proteins (ARPs) would be helpful in the discovery of new therapeutic targets and the design of novel drugs to control the potential spread of antibiotic resistance. In this work, a support vector machine (SVM)-based ARP prediction system was developed using 1308 ARPs and 15587 non-ARPs. Its performance was evaluated using 313 ARPs and 7156 non-ARPs. The computed prediction accuracy was 88.5% for ARPs and 99.2% for non-ARPs. A potential application of this method is the identification of ARPs non-homologous to proteins of known function. Further genome screening found that ca. 3.5% and 3.2% of proteins in Escherichia coli and Staphylococcus aureus, respectively, are potential ARPs. These results suggest the usefulness of SVMs for facilitating the identification of ARPs. The software can be accessed at SARPI (Server for Antibiotic Resistance Protein Identification).

Evaluation of virtual screening performance of support vector machines trained by sparsely distributed active compounds

Virtual screening performance of support vector machines (SVM) depends on the diversity of training active and inactive compounds. While diverse inactive compounds can be routinely generated, the number and diversity of known actives are typically low. We evaluated the performance of SVM trained by sparsely distributed actives in six MDDR biological target classes composed of a high number of known actives (983-1645) of high, intermediate, and low structural diversity (muscarinic M1 receptor agonists, NMDA receptor antagonists, thrombin inhibitors, HIV protease inhibitors, cephalosporins, and renin inhibitors). SVM trained by regularly sparse data sets of 100 actives show improved yields at substantially reduced false-hit rates compared to those of published studies and those of Tanimoto-based similarity searching method based on the same data sets and molecular descriptors. SVM trained by very sparse data sets of 40 actives (2.4%-4.1% of the known actives) predicted 17.5-39.5%, 23.0-48.1%, and 70.2-92.4% of the remaining 943-1605 actives in the high, intermediate, and low diversity classes, respectively, 13.8-68.7% of which are outside the training compound families. SVM predicted 99.97% and 97.1% of the 9.997 M PUBCHEM and 167K remaining MDDR compounds as inactive and 2.6%-8.3% of the 19,495-38,483 MDDR compounds similar to the known actives as active. These suggest that SVM has substantial capability in identifying novel active compounds from sparse active data sets at low false-hit rates.

A support vector machines approach for virtual screening of active compounds of single and multiple mechanisms from large libraries at an improved hit-rate and enrichment factor

Support vector machines (SVM) and other machine-learning (ML) methods have been explored as ligand-based virtual screening (VS) tools for facilitating lead discovery. While exhibiting good hit selection performance, in screening large compound libraries, these methods tend to produce lower hit-rate than those of the best performing VS tools, partly because their training-sets contain limited spectrum of inactive compounds. We tested whether the performance of SVM can be improved by using training-sets of diverse inactive compounds. In retrospective database screening of active compounds of single mechanism (HIV protease inhibitors, DHFR inhibitors, dopamine antagonists) and multiple mechanisms (CNS active agents) from large libraries of 2.986 million compounds, the yields, hit-rates, and enrichment factors of our SVM models are 52.4-78.0%, 4.7-73.8%, and 214-10,543, respectively, compared to those of 62-95%, 0.65-35%, and 20-1200 by structure-based VS and 55-81%, 0.2-0.7%, and 110-795 by other ligand-based VS tools in screening libraries of >or=1 million compounds. The hit-rates are comparable and the enrichment factors are substantially better than the best results of other VS tools. 24.3-87.6% of the predicted hits are outside the known hit families. SVM appears to be potentially useful for facilitating lead discovery in VS of large compound libraries.

[Research on development of gold immunochromagraphic assay test kit for serum Coxsackievirus IgM antibody.]

BACKGROUND

To develop gold immunochromatographic assay (GICA) test kit for serum Coxsackievirus IgM antibody and optimize the key experiment conditions.

METHODS

Colloidal gold particles of 20 nm were prepared and coupled with sheep anti-human IgM, the gold immunochromatography assay test kit was setup for serum Coxsackievirus IgM antibody.

RESULTS

The spheroidal colloid gold particles of 20 nm showed bright red in color. The minimal stable concentration (MSC) of gold sheep anti-human IgM was 1 ug/ml, and the suitable stable concentration (SSC) was 1.5 ug/ml. The pH 8.2 was appropriate; 30 sera samples were tested by GICA and ELISA, there was no significant difference between the two methods.

CONCLUSION

The quality of gold immunochromatography assay test kit is associated with such factors as the quality and quantity of antigen or antibody, colloid gold particles, buffers, etc.

Differential expression of prostaglandin E receptor subtype EP2 in rat uterus during early pregnancy

PGE2 is essential for mammalian female reproduction. This study was to examine the expression of EP2 gene in the rat uterus during early pregnancy, delayed implantation and artificial decidualization by in situ hybridization and immunohistochemistry. There was no detectable EP2 mRNA expression in the uterus from days 1 to 4 of pregnancy (day 1 = day of vaginal sperm). A low level of EP2 immunostaining was observed in the luminal and glandular epithelium from days 1 to 4 of pregnancy. Both EP2 mRNA and protein expression were highly detected in the luminal epithelium at implantation sites on day 6 of pregnancy. EP2 expression decreased from day 7 of pregnancy and was undetectable on days 8 and 9 of pregnancy. After delayed implantation was terminated by estrogen treatment and the embryo implanted, both EP2 mRNA and protein expression were strongly observed in the luminal epithelium at the implantation site. There was no detectable EP2 expression in both control and decidualized uteri. In conclusion, these data suggest that EP2 expression at implantation site may play an important role during embryo implantation in rats.

Characterization of two labor-induced genes, DSCR1 and TCTE1L, in the pregnant ovine myometrium

In the present study we characterized two labor-induced genes, DSCR1 (Down syndrome candidate region 1) and TCTE1L (murine t-complex like), which were identified by suppression subtractive hybridization in the pregnant ovine myometrium. DSCR1 and TCTE1L cDNA sequences were retrieved from a custom-made labor-myometrial cDNA library by hybridization screening. The characterized cDNA sequences include 5'-untranslated region (UTR), coding region and 3'-UTR, which are 12 bp, 351 bp and 1716 bp for TCTE1L, and 64 bp, 594 bp and 1539 bp for DSCR1 respectively. The two cDNA sequences encode proteins of 116 and 197 amino acids for TCTE1L and DSCR1 respectively. Northern analysis further confirmed the significant increases of myometrial DSCR1 and TCTE1L mRNA associated with spontaneous term labor (n=6) compared with gestation-matched controls not in labor (n=6). The abundance of DSCR1 and TCTE1L mRNA was attenuated when myometrial contraction was inhibited by Nimesulide (n=6), a specific prostaglandin H synthase 2 inhibitor. Fetal occupancy greatly upregulated DSCR1 and TCTE1L mRNA in the gravid horn during betamethasone-induced premature labor (n=6) compared with the non-gravid horn not in labor (n=3). Estradiol upregulated TCTE1L mRNA, but had no effect on DSCR1 mRNA expression in the non-pregnant sheep myometrium. Progesterone alone had no effect on both DSCR1 and TCTE1L mRNA expression, however progesterone antagonized estradiol's stimulating effect on myometrial TCTE1L mRNA expression in ovariectomized non-pregnant sheep. Upregulation of DSCR1 and TCTE1L in both betamethasone-induced premature labor and spontaneous term labor and inhibition of their expression by Nimesulide suggest a functional role of these two genes in myometrial activation associated with onset of labor. Mechanical stretch, labor and steroids differentially regulated DSCR1 and TCTE1L mRNA in the pregnant and non-pregnant sheep myometrium.

Differential gene expression between visceral and subcutaneous fat depots

Abdominal obesity has been linked to the development of insulin resistance and Type 2 diabetes mellitus (DM2). By surgical removal of visceral fat (VF) in a variety of rodent models, we prevented insulin resistance and glucose intolerance, establishing a cause-effect relationship between VF and the metabolic syndrome. To characterize the biological differences between visceral and peripheral fat depots, we obtained perirenal visceral (VF) and subcutaneous (SC) fat from 5 young rats. We extracted mRNA from the fat tissue and performed gene array hybridization using Affymetrix technology with a platform containing 9 000 genes. Out of the 1 660 genes that were expressed in fat tissue, 297 (17.9 %) genes show a two-fold or higher difference in their expression between the two tissues. We present the 20 genes whose expression is higher in VF fat (by 3 - 7 fold) and the 20 genes whose expression is higher in SC fat (by 3 - 150 fold), many of which are predominantly involved in glucose homeostasis, insulin action, and lipid metabolism. We confirmed the findings of gene array expression and quantified the changes in expression in VF of genes involved in insulin resistance (PPARgamma leptin) and its syndrome (angiotensinogen and plasminogen activating inhibitor-1, PAI-1) by real-time PCR (qRT-PCR) technology. Finally, we demonstrated increased expression of resistin in VF by around 12-fold and adiponectin by around 4-fold, peptides that were not part of the gene expression platform. These results indicate that visceral fat and subcutaneous fat are biologically distinct.

Effect of ultrasound on the structural and physiochemical properties of organosolv soluble hemicelluloses from wheat straw

Effect of ultrasound on the yield and physiochemical properties of hemicelluloses from wheat straw using 0.5 M NaOH in 60% aqueous methanol has been comparatively studied. The results showed that applying sonication for 5, 10, 15, 20, 25, 30, and 35 min resulted in an increasing yield of hemicelluloses by 2.9%, 3.9%, 6.0%, 8.6%, 8.6%, 8.6%, and 9.2% of the original hemicelluloses, respectively, in comparison with the experiment performed without ultrasonic assistance. The hemicelluloses isolated by ultrasound-assisted extraction, showed a slightly lower molecular weight, associated lignin, and thermal stability during the first stage of decomposition, but slightly more linear as compared to the hemicelluloses obtained by classical method without ultrasonic irradiation. No substantial differences in the main structure features between the hemicellulosic preparations isolated by classical or ultrasound-assisted extractions were found.

Congou tea drinking and oesophageal cancer in South China

The study from a large hospital-based case-control for 1248 cases with oesophageal cancer and the same number of controls in South China showed that Congou, a grade of Chinese black tea, may protect against cancers of the oesophagus and reduce the risk of a combination of alcohol drinking and smoking (especially smoking), regardless of temperature when drinking.

Characterization of topology-, gestation- and labor-related changes of a cassette of myometrial contraction-associated protein mRNA in the pregnant baboon myometrium

Our objective was to examine the topology-, gestation- and labor-related changes of estrogen receptor (ER)alpha, progesterone receptor (PR), oxytocin receptor (OTR) and thrombospondin-1 (TSP1) mRNA in pregnant baboon myometrium. ER alpha, PR, OTR and TSP1 mRNAs extracted from the lower uterine segment and fundal myometrium of pregnant baboons not in labor between 121 and 180 days of gestational age (n=9) and in established spontaneous labor between 164 and 193 days of gestational age (n=5) were analyzed by Northern blot. There were no topology-, gestation- or labor-related changes of ER alpha and PR mRNA in or between the lower uterine segment or/and the fundus. OTR mRNA was the same in the lower uterine segment and the fundus from baboons not in labor and non-labor fundal, but not lower uterine segment, myometrial OTR mRNA increased with gestation (R(2)=0.81, P<0.05). Fundal OTR mRNA rose significantly compared with the lower uterine segment during spontaneous labor. TSP1 mRNA increased significantly in both the fundus and lower uterine segment during labor. TSP1 mRNA in the lower uterine segment during spontaneous labor was higher than in the fundus during spontaneous labor. In conclusion, fundal and lower uterine segment ER alpha and PR mRNA remained unchanged in late gestation and spontaneous labor. The increased OTR mRNA may serve as a mechanism to increase uterine sensitivity to OT during late gestation. The higher fundal OTR mRNA compared with the lower uterine segment provides polarity which assists fetal expulsion by uterine contractions during labor. The significance of increased TSP1 mRNA during labor may relate to homeostasis and merits further study.

Lyme disease Borrelia spp. in ticks and rodents from northwestern China

In May 1999, field surveys of Lyme disease spirochetes were conducted around the Tianshan Mountains in Xinjiang Uygur Autonomous Region in northwestern People's Republic of China. Ixodes persulcatus ticks were obtained in a Tianchi Lake valley with primary forest, while the tick fauna was poor in the semidesert or at higher altitudes in this region. Species identities were confirmed by molecular analysis in which an internal transcribed spacer sequence was used. Of 55 adult ticks, 22 (40%) were positive for spirochetes as determined by Barbour-Stoenner-Kelly culture passages. In addition, some rodents, including Apodemus uralensis (5 of 14 animals) and Cricetulus longicaudatus (the only animal examined), and some immature stages of I. persulcatus (4 of 11 ticks) that had fed on A. uralensis were positive for spirochetes. Based on 5S-23S rRNA intergenic spacer restriction fragment length polymorphism analysis and reactivity with monoclonal antibodies, 35 cultures (including double isolation cultures) were identified as Borrelia garinii (20 isolates, including 9 Eurasian pattern B isolates and 11 Asian pattern C isolates), Borrelia afzelii (10 pattern D isolates), and mixed cultures (5 cultures, including isolates that produced B. garinii patterns B and C plus B. afzelii pattern D). These findings revealed that Lyme disease pathogens are distributed in the mountainous areas in northwestern China even though it is an arid region, and they also confirmed the specific relationship between I. persulcatus and genetic patterns of Borrelia spp. on the Asian continent.

Regulation of cyclin-dependent kinase 5 and casein kinase 1 by metabotropic glutamate receptors

Cyclin-dependent kinase 5 (Cdk5) is a multifunctional neuronal protein kinase that is required for neurite outgrowth and cortical lamination and that plays an important role in dopaminergic signaling in the neostriatum through phosphorylation of Thr-75 of DARPP-32 (dopamine and cAMP-regulated phosphoprotein, molecular mass 32 kDa). Casein kinase 1 (CK1) has been implicated in a variety of cellular functions such as DNA repair, circadian rhythm, and intracellular trafficking. In the neostriatum, CK1 has been found to phosphorylate Ser-137 of DARPP-32. However, first messengers for the regulation of Cdk5 or CK1 have remained unknown. Here we report that both Cdk5 and CK1 are regulated by metabotropic glutamate receptors (mGluRs) in neostriatal neurons. (S)-3,5-dihydroxyphenylglycine (DHPG), an agonist for group I mGluRs, increased Cdk5 and CK1 activities in neostriatal slices, leading to the enhanced phosphorylation of Thr-75 and Ser-137 of DARPP-32, respectively. The effect of DHPG on Thr-75, but not on Ser-137, was blocked by a Cdk5-specific inhibitor, butyrolactone. In contrast, the effects of DHPG on both Thr-75 and Ser-137 were blocked by CK1-7 and IC261, specific inhibitors of CK1, suggesting that activation of Cdk5 by mGluRs requires CK1 activity. In support of this possibility, the DHPG-induced increase in Cdk5 activity, measured in extracts of neostriatal slices, was abolished by CK1-7 and IC261. Treatment of acutely dissociated neurons with DHPG enhanced voltage-dependent Ca(2+) currents. This enhancement was eliminated by either butyrolactone or CK1-7 and was absent in DARPP-32 knockout mice. Together these results indicate that a CK1-Cdk5-DARPP-32 cascade may be involved in the regulation by mGluR agonists of Ca(2+) channels.

In vivo evidence for stimulation of placental, myometrial, and endometrial prostaglandin G/H synthase 2 by fetal cortisol replacement after fetal adrenalectomy

Fetal glucocorticoid-induced premature labor in sheep is an established model of premature labor. However, the pathways by which fetal cortisol triggers subsequent maternal endocrine changes, including enhanced PG synthesis, leading to labor are unclear. The current study was undertaken to determine whether cortisol administration to adrenalectomized fetuses to clamp fetal cortisol at levels present early in the late gestation rise, which are inadequate to produce labor, can stimulate placental, myometrial, and endometrial prostaglandin G/H synthase 2 mRNA and protein expression. At 109--13 d gestation, fetal sheep adrenals were removed (n = 8), or sham surgery was performed (n = 4). From d 6 postadrenalectomy, maternal and fetal plasma cortisol were determined daily by RIA. From d 7 postadrenalectomy, cortisol (4 micro/min) was continuously infused iv to four adrenalectomized fetuses. Endometrium, myometrium, and placentome were collected from all three groups of ewes (n = 4 for each group), and total RNA and proteins were extracted from each intrauterine tissue and analyzed by Northern and Western for prostaglandin G/H synthase 2 mRNA and protein. P45017 alpha hydroxylase mRNA was analyzed in the placentome by Northern blot. Data were analyzed by ANOVA. Plasma cortisol levels remained low in sham-operated and adrenalectomized fetus, whereas during cortisol infusion to adrenalectomized and cortisol-treated fetuses, plasma cortisol increased to the late gestation level. After adrenalectomy, prostaglandin G/H synthase 2 did not change in any tissue studied. Fetal plasma cortisol replacement to late gestation levels increased prostaglandin G/H synthase 2 to levels similar to term levels in all three tissues. PGHS1 mRNA and protein did not change in any group studied. There was a minimal increase in P45017 alpha hydroxylase mRNA in the placentome in the adrenalectomized and cortisol-treated group. Cortisol- induced labor further increased P45017 alpha hydroxylase mRNA in the placentome compared with that in adrenalectomized and cortisol-treated animals. These data provide evidence for in vivo cortisol up-regulation of prostaglandin G/H synthase 2, but not PGHS1, in late gestation in the ovine placentome, myometrium, and endometrium. As stimulation of the estrogen biosynthetic pathway was minimal in the adrenalectomized and cortisol-treated group, these data provide support for the concept that cortisol has a direct effect on prostaglandin G/H synthase 2 expression in addition to its classical indirect pathway on prostaglandin G/H synthase 2 as a result of estrogen synthesis.

Hyperglycemia modulates angiotensinogen gene expression

Elevated plasma angiotensinogen (AGT) levels have been demonstrated in insulin-resistant states such as obesity and type 2 diabetes mellitus (DM2), conditions that are directly correlated to hypertension. We examined whether hyperinsulinemia or hyperglycemia may modulate fat and liver AGT gene expression and whether obesity and insulin resistance are associated with abnormal AGT regulation. In addition, because the hexosamine biosynthetic pathway is considered to function as a biochemical sensor of intracellular nutrient availability, we hypothesized that activation of this pathway would acutely mediate in vivo the induction of AGT gene expression in fat and liver. We studied chronically catheterized lean (approximately 300 g) and obese (approximately 450 g) Sprague-Dawley rats in four clamp studies (n = 3/group), creating physiological hyperinsulinemia (approximately 60 microU/ml, by an insulin clamp), hyperglycemia (approximately 18 mM, by a pancreatic clamp using somatostatin to prevent endogenous insulin secretion), or euglycemia with glucosamine infusion (GlcN; 30 micromol. kg(-1). min(-1)) and equivalent saline infusions (as a control). Although insulin infusion suppressed AGT gene expression in fat and liver of lean rats, the obese rats demonstrated resistance to this effect of insulin. In contrast, hyperglycemia at basal insulin levels activated AGT gene expression in fat and liver by approximately threefold in both lean and obese rats (P < 0.001). Finally, GlcN infusion simulated the effects of hyperglycemia on fat and liver AGT gene expression (2-fold increase, P < 0.001). Our results support the hypothesis that physiological nutrient "pulses" may acutely induce AGT gene expression in both adipose tissue and liver through the activation of the hexosamine biosynthetic pathway. Resistance to the suppressive effect of insulin on AGT expression in obese rats may potentiate the effect of nutrients on AGT gene expression. We propose that increased AGT gene expression and possibly its production may provide another link between obesity/insulin resistance and hypertension.

Growth, neurobehavioral and circadian rhythm development in newborn baboons

We measured body temperature continuously using telemetry to determine the development of circadian rhythmicity in neonatal baboons after birth. Twelve fetal baboons (nine males and three females) of known gestational age ranging from 167 to 193 d were studied. We eliminated the influence of maternal factors by hand rearing these infants from the moment of birth until 45 d of life. All infants showed steady growth in body weight, head circumference, and crown-rump length. Neurobehavioral responses including visual and auditory orientation, motor maturity, irritability, and consolability increased as a function of age. Circadian rhythms of body temperature were present in the second week of life, and the amplitude of this rhythm increased throughout the developmental period studied. The increase in the amplitude of circadian body temperature rhythm independent of environmental time cues may indicate the maturation of the brain. These neonatal nonhuman primates offer an excellent model for studying neurobehavioral development and maturation of circadian rhythms while controlling external factors in a manner that is not possible with human neonates.