ObjectiveTo investigate the platelet metabolomic characteristics of the rat model of coronary heart disease （CHD） with blood stasis syndrome （BSS） based on ultra-high performance liquid chromatography coupled with quadrupole-Orbitrap high-resolution mass spectrometry （UPLC-Q-Exactive Orbitrap-MS）， screen potential biomarkers and metabolic pathway information， and elucidate the association mechanism between platelet metabolic disorders and myocardial injury. MethodsA total of 12 rats were randomized into a normal group and a modle group. The rat model of CHD-BSS was established by continuous high-fat feeding， intragastric administration of vitamin D3 in divided doses combined with subcutaneous injection of isoproterenol. Additionally， changes in standard lead Ⅱ electrocardiogram （ECG） and myocardial histopathological alterations of rats in the two groups were observed to evaluate myocardial injury in the modle group. After preprocessing of the untargeted metabolomic data of platelet samples from the two groups， multivariate statistical analysis and differential screening were performed sequentially. Principal component analysis （PCA） was performed to verify the separation of metabolic profiles of samples between groups. An orthogonal partial least squares-discriminant analysis （OPLS-DA） model was then constructed to preliminarily screen potential differential metabolites based on model parameters. Secondary screening was conducted with the fold change of metabolite expression to finally identify metabolites with significant intergroup differences， and metabolic pathway enrichment analysis was carried out based on these differential metabolites. Finally， potential platelet-specific biomarkers were identified based on receiver operating characteristic（ROC） curves. ResultsCompared with the normal group， the modle group presented obvious elevation of the J point and an ST-segment elevation greater than 0.1 mV on ECG， as well as pathological injuries such as loose arrangement of fibers and cellular vacuolar degeneration in the myocardial tissue. A total of 370 differentially expressed metabolites were dysregulated in the modle group， involving 8 significantly enriched metabolic pathways，such as purine metabolism， arachidonic acid metabolism， oxidative phosphorylation and adenosine monophosphate-activated protein kinase （AMPK） signaling pathway. Nine differential metabolites enriched in these pathways showed statistically significant differences in content. ROC curve analysis revealed that the area under the curve（AUC） of all characteristic metabolites was higher than 0.8. Among them， the AUC values of four metabolites， including sphinganine 1-phosphate， sphingosine 1-phosphate， 12-ketoleukotriene B₄ and 14，15-dihydroxyeicosatrienoic acid， reached 1.0， indicating their potential as biomarkers. ConclusionPlatelet metabolic characteristics are significantly altered in the rat model of CHD-BSS. The screened potential biomarkers possess favorable diagnostic performance. The pathological changes mediated by these metabolites， including inflammatory response， thrombosis， and energy metabolism disorders， serve as critical mechanisms for abnormal platelet activation and subsequent myocardial injury. Platelet metabolomics provides a new perspective for the screening of biomarkers and research on pathological mechanisms of CHD-BSS.

Objective To investigate the development and dynamic changes of cysts in the brain of mice following infection with different forms of Toxoplasma gondii, so as to provide insights into for toxoplasmosis prevention and control. Methods ICR mice at ages of 6 to 8 weeks, each weighing 20 to 25 g, were intraperitoneally injected with tachyzoites of the T. gondii PRU strain at a dose of 1 × 10⁵ tachyzoites per mouse, orally administered with cysts at a dose of 20 oocysts per mouse or oocysts at a dose of 200 oocysts per mouse for modeling chronic T. gondii infection in mice, and the clinical symptoms and survival of mice were observed post-infection. Mice were orally infected with T. gondii cysts at doses of 10 (low-dose group), 20 (medium-dose group), 40 cysts per mouse (high-dose group), and the effect of different doses of T. gondii infections on the number of cysts was examined in the mouse brain. Mice were orally administered with T. gondii cysts at a dose of 20 cysts per mouse, and grouped according to gender (female and male) and time points of infections (20, 30, 60, 90, 120, 150, 180 days post-infection), and the effects of gender and time points of infections on the number of cysts was examined in the mouse brain. In addition, mice were divided into the tachyzoite group (Group T), the first-generation cyst group (Group C1), the second-generation cyst group (Group C2), the third-generation cyst (Group C3) and the fourth-generation cyst group (Group C4). Mice in the Group T were intraperitoneally injected with T. gondii tachyzoites at a dose of 1 × 10⁵ tachyzoites per mouse, and the cysts were collected from the mouse brain tissues 30 days post-infection, while mice in the Group C1 were orally infected with the collected cysts at a dose of 30 cysts per mouse. Continuous passage was performed by oral administration with cysts produced by the previous generation in mice, and the effect of continuous passage on the number of cysts was examined in the mouse brain. Results Following infection with T. gondii tachyzoites, cysts and oocysts in mice, obvious clinical symptoms were observed on days 6 to 13 and mice frequently died on days 7 to 12. The survival rates of mice were 67.0%, 87.0% and 53.0%, and the mean numbers of cysts were (516.0 ± 257.2), (1 203.0 ± 502.0) and (581.0 ± 183.1) in the mouse brain (F = 11.94, P < 0.01) on day 30 post-infection with T. gondii tachyzoites, cysts and oocysts, respectively, and the numbers of cysts in the brain tissues were significantly lower in mice infected with T. gondii tachyzoites and oocysts than in those infected with cysts (all P values < 0.01). The survival rates of mice were 87.0%, 87.0% and 60.0%, and the mean numbers of cysts were (953.0 ± 355.5), (1 084.0 ± 474.3) and (1 113.0 ± 546.0) in the mouse brain in the low-, medium- and high-dose groups on day 30 post-infection, respectively (F = 0.42, P > 0.05). The survival rates of male and female mice were 73.0% and 80.0%, and the mean numbers of cysts were (946.4 ± 411.4) and (932.1 ± 322.4) in the brain tissues of male and female mice, respectively (F = 1.63, P > 0.05). Following continuous passage, the mean numbers of cysts were (516.0 ± 257.2), (1 203.0 ± 502.0), (896.8 ± 332.3), (782.5 ± 423.9) and (829.2 ± 306.0) in the brain tissues of mice in the T, C1, C2, C3 and C4 groups, respectively (F = 4.82, P < 0.01), and the number of cysts was higher in the mouse brain in Group 1 than in Group T (P < 0.01). Following oral administration of 20 T. gondii cysts in mice, cysts were found in the moues brain for the first time on day 20 post-infection, and the number of cysts gradually increased over time, peaked on days 30 and 90 post-infection and then gradually decreased; however, the cysts were still found in the mouse brain on day 180 post-infection. Conclusions There is a higher possibility of developing chronic T. gondii infection in mice following infection with cysts than with oocysts or tachyzoites and the most severe chronic infection is seen following infection with cysts. The number of cysts does not correlate with the severity of chronic T. gondii infection, and the number of cysts peaks in the mouse brain on days 30 and 90 post-infection.

Objective: To understand the epidemic trend of tobacco use among junior middle school students in Shunyi District of Beijing in recent 5 years, and to provide scientific basis for formulating adolescent tobacco control strategies and intervention measures. Methods: The two stage sampling method was used to survey 3 junior middle school schools randomly selected from Shunyi District, Beijing, in November 2013, December 2015 and November 2017. The number of students surveyed each year was 1 520, 1 404 and 1 467 respectively. Results: A total of 4 500 questionnaires were distributed and 4 391 questionnaires were valid, with an effective rate of 97.6%. The current smoking rate and the attempting smoking rate in Shunyi District junior high school students increased substantially, the difference was statistically significant(χ2=9.15, 11.54, P<0.01). The exposure rate of second-hand smoke among junior high school students in Shunyi District is increasing year by year. The current smoking rate and the attempting smoking rate of second-hand smoke at home and in public places were higher than those of non-exposed ones. The differences in the current smoking rates of junior high school students (χ2=25.86, 37.61, P<0.01) and the attempting smoking rate (χ2=49.51, 63-86, P<0.01) were statistically significant. The influence of Shunyi District junior high school students through different tobacco information access channels on the current smoking rate of junior high school students increased year by year. Different tobacco information access channels have significant difference in the influence of the junior middle school students’ attempting smoking rate(P<0.05). Conclusion The overall tobacco use of junior high school students in Shunyi District of Beijing is increasing by year. The exposure of second-hand smoke is not optimistic, and the supervision of tobacco information acquisition channels is urgent to be strengthened.

JB25 and JB26 are new HIV-1 nonnucleoside reverse transcriptase inhibitors, and show potent anti-HIV activities. Sequential passage experiments with wild-type virus were performed to select and identify mutations induced by these two compounds in vitro. For the initial passage, compounds were present at approximately 2-fold IC50 in MT-2 cells. When cytopathic effect (CPE) was observed in more than 75% of the cells, the culture supernatants were collected. For the subsequent passages, fresh MT-2 cells were infected with 1 mL supernatants from the previous passage (regardless of the virus titer) and cultured in the presence of the compounds at concentrations that were increased 2-fold compared with that in the previous passage. This procedure was repeated with increasing concentrations for 12 passages. JB25 had amino acid substitution L100I (TTA-->ATA) at passage 6, and then changed into 100 M (ATA-->ATG) at passage 12, which was rare mutation form and had not been reported. At the same time, Y188C (TAT-->TGT) mutation appeared at passage 10. For JB26, there was a L100I (TTA-->ATA) mutation at passage 10. In a word, JB25 and JB26 showed a low genetic barrier to the development of resistance, and the resistance to JB26 developed slower than JB25. The mutations selected by JB25 and JB26 were mainly associated with codons 188 and 100 of HIV-1 reverse transcriptase.

AIM:To study the senescence of human umbilical vein endothelial cells(HUVECs) and Bcl-2,Bax gene expression associated with apoptosis induced by angiotensinⅡ(AngⅡ).METHODS:HUVECs were cultured in vitro and the cell viability was observed by methyl thiazolyl tetrazolium(MTT).HUVECs were intervened by AngⅡ and valsartan(AngⅡ type 1 receptor blocking) and divided into 3 groups:the control group,AngⅡ group(stimulated with AngⅡ10-6mol/L for 48 h),valsartan group(valsartan was added to cells 1 h before 10-6mol/L AngⅡ treatment).?-gal staining aod cell cycle analysis were used to identify the cell aging status.Morphologic changes and percentage of apoptosis were assayed with Hoechst33258 under fluorescent microscope.The expressions of Bcl-2 and Bax,and the apoptosis-associated genes were detected by immunocytochemical staining,RT-PCR and Western blotting.RESULTS:The cell viability by AngⅡ-induced cells was(81.9%?4.1)%,the positive cell number of ?-gal staining was significantly higher in AngⅡ-induced cells(80.10%?6.81)% than that in the control cells.The cell cycle was at G0-G1(91.36%?6.45)%,the apoptotic cells significantly increased(31.84?2.86)% under fluorescent microscope.In valsartan group,Bcl-2 mRNA and protein expression increased markedly(P