[Molecular characteristics and drug susceptibility analysis of Streptococcus agalactiae from respiratory specimen sources].

To study the carriage status of drug susceptibility, clonal complex groups, serotypes, surface proteins and virulence genes of Streptococcus agalactiae from respiratory specimen sources. A total of 35 strains of S.agalactiae meeting the criteria were collected from 3 hospitals in 2 locations, Tangshan and Jinan. The age span of the patients was 3 days-92 years, and the percentage of elderly patients≥60 years was 71.5%.The susceptibility to 9 antimicrobial drugs was measured and analyzed using the micro broth dilution method. The strains were 100.0% sensitive to penicillin, linezolid, vancomycin, and ceftriaxone; However, it exhibits high resistance rates to erythromycin, clindamycin and levofloxacin, at 97.1%, 85.7% and 82.9% respectively; and the resistance rates to tetracycline and chloramphenicol were 34.3% and 14.2%, respectively. Genome sequence determination and analysis showed that 16 resistance genes were detected in 35 strains, among which: macrolide and lincosamide resistance genes were mainly ermB, with a carrying rate of 74.2%; tetracycline resistance genes were mainly tetM, with a carrying rate of 25.7%; in addition, the mutation rates of the quinolone resistance determinants gyrA and parC were 88.5% and 85.7%, respectively. 35 strains belonged to 6 ST types and 4 clonal groups, with CC10/ST10 as the main one, accounting for 62.8%; they contained 4 serotypes of Ⅰb, Ⅱ, Ⅲ, and Ⅴ, as well as 1 untyped strain, with serotype Ⅰb as the main one, accounting for 65.7%. The strains carried three pilus types, PI1+PI2a, PI2a and PI2b types, respectively, and detected five surface proteins, alpha, alp1, rib, srr, and rdf_0594, and seven virulence factors, cba, cfb, cylE, fbsA, hylB, lmb, and pavA. Overall, S.agalactiae isolated from respiratory tract specimens is predominantly sourced from elderly patients, with CC10 strains being most prevalent. These strains harbor multiple drug-resistant and virulence genes, demonstrating elevated resistance rates to macrolides, lincosamides, and quinolones. This emphasizes the necessity for vigilant attention to the health threat posed by S. agalactiae from respiratory tract speciments of elderly patients.

[Protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A-induced acute liver injury in mice].

Objective: To investigate the protective effect of intraperitoneal transplantation of human liver-derived stem cells at different times against concanavalin A (ConA)-induced acute liver injury in mice. Methods: A total of 88 male C57BL/6 mice were randomly divided into normal control group (group C), ConA model group (group M), and human liver-derived stem cells (HYX1)+ConA group (group E); according to the interval between phosphate buffer/HYX1 injection and ConA injection, Groups M and E were further divided into 3-hour groups (M1 and E1 groups), 6-hour groups (M2 and E2 groups), 12-hour groups (M3 and E3 groups), 24-hour groups (M4 and E4 groups), and 48-hour groups (M5 and E5 groups). The levels of alanine aminotransferase (ALT), aspartate transaminase (AST), and total bilirubin (TBil) in peripheral blood were measured, liver tissue sections were used to observe pathological changes, and the Ishak score for liver inflammation was determined. The independent samples t-test was used for comparison between groups, and P < 0.05 was considered statistically significant. Results: The levels of ALT, AST, and TBil in group C were (36.25±1.16) U/L, (120.20±5.77) U/L, and (2.20±0.23) µmol/L, respectively; the levels of ALT, AST, and TBil and Ishak score were (8 721.23±837.39) U/L, (8 110.31±290.10) U/L, (8.41±0.10) µmol/L, and (13.32±1.30), respectively, in group M1, (8 334.31±666.50) U/L, (7 560.20±760.34) U/L, (10.40±0.80) µmol/L, and (12.67±0.81), respectively, in group M2, (8 960.75±551.93) U/L, (8 535.62±675.14) U/L, (10.95±1.43) µmol/L, and (14.57±0.65), respectively, in group M3, (8 618.57±886.40) U/L, (11 440.54 ± 1 327.86) U/L, (13.30±1.86) µmol/L, and (13.21±1.06), respectively, in group M4, and (10 170.13±1 112.37) U/L, (11 470.56±1 108.40) U/L, (12.75±1.55) µmol/L, and (15.07±1.58), respectively, in group M5. The levels of ALT, AST, and TBil and Ishak score were (1 016.35±163.47) U/L, (952.30±103.91) U/L, (7.77±0.62) µmol/L, and (3.50±0.21), respectively, in group E1, (42.10±6.20) U/L, (126.72±13.33) U/L, (3.41±0.53) µmol/L, and (2.01±0.40), respectively, in group E2, (44.21±4.30) U/L, (216.71±35.88) U/L, (3.47±0.44) µmol/L, and (2.13±0.25), respectively, in group E3, (2 909.69±212.14) U/L, (2 988.43±333.70) U/L, (7.03±0.93) µmol/L, and (4.70±0.50), respectively, in group E4, and (7 874.26±799.60) U/L, (10 940.54±947.35) U/L, (10.53±1.09) µmol/L, and (8.60±0.83), respectively, in group E5. Groups M1-M5 had significantly higher levels of ALT, AST, and TBil than group C (all P < 0.01), and groups M1-M4 had significantly higher levels of AST and ALT than groups E1-E4 (all P < 0.01), while there were no significant differences in the levels of AST and ALT between groups M5 and E5 (both P > 0.05). The pathological sections of liver tissue showed that compared with group M, group E had significant reductions in the degree of necrosis and Ishak score (both P < 0.05). Conclusion: Intraperitoneal transplantation of human liver-derived stem cells has a protective effect against ConA-induced acute liver injury in mice, and the injection at 6 and 12 hours in advance has the best protective effect.

Flexible modulation of electronic and magnetic properties of zigzag H-MoS2 nanoribbons by crack defects.

The effects of crack defects on electronic and magnetic properties of zigzag MoS2 nanoribbons are investigated systematically by first-principles calculations based on spin-polarized density functional theory. We find that not only the electronic and spin transport ability of zigzag MoS2 nanoribbons can be enhanced significantly by the armchair crack defects, but also their magnetism could be modulated flexibly by crack defects. Our study suggests that the introduction of crack defect is a feasible way to modulate the electronic and magnetic properties of zigzag MoS2 nanoribbons. We further propose that the crack defects may also provide a useful tool for improving the performance of devices.

Hydrogen sulfide modulates gastric acid secretion in rats via involvement of substance P and nuclear factor-κB signaling.

Hydrogen sulfide (H2S) promotes gastric acid secretion in rats. The present study aimed to test the hypothesis that H2S regulates this response via activating TRPV1 channel and through activation of the nuclear factor-κB (NF-κB) pathway. Male Wistar rats were randomly divided into the sodium hydrosulfide (NaHS, 100 µmol/kg b.w.) group, pyrrolidine dithiocarbamate (PDTC, 100 µmol/kg b.w.) group, PDTC (100 µmol/kg b.w.) + NaHS (100 µmol /kg b.w.) group, capsazepine (0.1 mM) + NaHS (100 µmol /kg b.w.) group and L703606 (0.1 mM) + NaHS (100 µmol /kg b.w.) group. The acidity of gastric juice before injection and after injection were determined by a pH meter. The results showed that sodium hydrosulfide (NaHS), an exogenous H2S donor, significantly reduced the pH of gastric juice when injected into the enterocoelia. Further, the promotional effect of NaHS on gastric acid secretion could be attenuated by capsazepine, a transient receptor potential vanilloid 1 (TRPV1) antagonist; L703606, a neurokinin 1 (NK1) receptor antagonist; and PDTC, a NF-κB inhibitor. The data from these experiments suggest that NaHS exerts an excitatory effect on gastric acid secretion possibly mediated by TRPV1 channel activation in sensory nerve terminals with the consequent release of substance P and in a NF-κB -dependent manner.

LncRNA profiling of skeletal muscles in Large White pigs and Mashen pigs during development.

Long noncoding RNA (lncRNA) has been increasingly implicated in the regulation of muscle development. Large White pigs have a higher muscle growth rate than do Mashen pigs. In the present study, the lncRNA expression profiles in skeletal muscle of these 2 pig breeds were compared at 1, 90, and 180 d of age using RNA sequencing. We obtained 2,718 million clean reads and identified a total of 5,153 novel lncRNA. We found 1,407 differentially expressed lncRNA that showed consistent expression patterns between the 2 breeds at all the 3 sampling points. Ten lncRNA were randomly selected, and their expression was validated using Real-time Quantitative PCR. In summary, this study identifies a number of lncRNA that correlate with muscle growth. The regulation and function of these lncRNA in muscle growth and development need to be further explored.

[Detection of Epstein-Barr virus and human papillomavirus in sinonasal malignant neoplasms].

OBJECTIVE: To investigate the existance of Epstein-Barr virus (EBV) and papilloma virus(HPV) in sinonasal malignant neoplasms. METHOD: EBV and HPV (including HPV6,11,16,18,33) gene were detected in paraffin-embedded tissues with polymerase chain reaction(PCR) from 32 cases of sinonasal malignant neoplasms. RESULT: EBV was detected in 12(37.5%), HPV in 21(65.6%); The coinfection of EBV and HPV was found in 6 cases with stage III-IV by TNM; 10 cases of nasal polyps contained neither EBV nor HPV. CONCLUSION: Like HPV, there may be relationship between EBV and sinonasal malignant neoplasms. The coinfection of EBV and HPV is related to stage III-IV by TNM of sinonasal malignant neoplasms.