Cleaning,Shaping, and Disinfecting Abilities of 2 Instrument Systems as Evaluated by a Correlative Micro–computed Tomographic and Histobacteriologic Approach

IntroductionThis study assessed the cleaning, shaping, and disinfection abilities of 2 instrumentation systems in molar root canals using a novel correlative analytical approach.MethodsThe root canals from extracted mandibular and maxillary molars with apical periodontitis were pair matched according to anatomic similarities as determined by micro–computed tomographic analysis and prepared with either XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n = 16) or Reciproc Blue (VDW, Munich, Germany) (n = 16) instruments and 2.5% sodium hypochlorite irrigation. Pre- and postpreparation micro–computed tomographic scans were used to identify and calculate the unprepared surface areas (shaping), which were histobacteriologically evaluated for the presence of residual bacteria (disinfection) and pulp tissue remnants (cleaning) in each canal third.ResultsUnprepared canal surface areas for XP-endo Shaper and Reciproc Blue in the full canal length were approximately 26% and 19% (P < .05), respectively (30% and 23% in the apical part of the canal, P > .05). Preparation with Reciproc Blue resulted in 37.5% canals free of bacteria in all sections examined and 56% in the apical sections only. XP-endo Shaper resulted in 44% canals free of bacteria in all sections, and 56% in the apical part of the canal only. Pulp tissue remnants were not observed in 31% (all canal sections) and 50% (apical canal sections) of specimens from both instrument systems. No significant differences were observed between instruments when comparing the amount of pulp tissue remnants and the number of cases negative for bacteria and tissue remnants (P > .05).ConclusionsAlthough the Reciproc Blue instrument had superior shaping ability in comparison with XP-endo Shaper, both systems performed similarly in cleaning and disinfecting root canals. Irregular canals and difficult-to-reach areas were not thoroughly cleaned and disinfected by any of the tested systems.     

Selection of an Escherichia coli O157:H7 bacteriophage for persistence in the circulatory system of mice infected experimentally

A bacteriophage lytic for Escherichia coli O157:H7 was isolated from bovine manure. Following in-vivo selection, the phage acquired the capacity to persist in the circulatory system of mice for at least 38 days. When mice were infected experimentally with E. coli O157:H7 (10(7) CFU/mouse), simultaneous injection of the mice with phage (10(8) PFU/mouse) cleared E. coli O157:H7 from the mice within 48 h.     

Toll-like receptors in Borrelia burgdorferi-induced inflammation

Lyme arthritis, the most common manifestation of late Lyme disease, has been associated with the presence of Borellia burgdorferi in the joint. However, it is still unclear whether the pathogen itself is able to elicit such a sustained inflammatory response, or whether an aberrant immunological reaction of the host is the main driving force. Borrelia antigens, including lipoproteins, flagellin and DNA, are ligands of Toll-like receptors, and can thus elicit a strong stimulation of host cells, such as neutrophils, mononuclear cells and resident tissue cells. Understanding the molecular basis of the signalling events caused by Borrelia lipoproteins will lead to a greater understanding of inflammation in Lyme arthritis and, hopefully, new treatment strategies for chronic antibiotic-resistant disease.     

Structure, Metabolism, and Functions of Peripheral Blood Lymphocytes during Long-Term Persistence of Epstein-Barr Virus

Study of surface architectonics, blast transformation potential, and cytochemical activity of peripheral blood lymphocytes from children infected with Epstein-Barr virus revealed imbalance between structural, metabolic, and functional state of lymphocytes. This imbalance persists in delayed period after infection and determines long-term viral persistence in the macroorganism.     

Persistence of varicella-zoster virus DNA in blood mononuclear cells of patients with varicella or zoster

Varicella-zoster virus (VZV) DNA was detectable by in-situ hybridization in blood mononuclear cells (MNCs) of patients with varicella or zoster for 2–56 days after the onset of a rash. VZV DNA was present in many MNCs from one acute varicella patient 2 days after the onset of the rash and was rarely found in MNCs during acute zoster, convalescent zoster, and convalescent varicella. The morphology of MNCs containing VZV was heterogenous, although most viral-DNA-containing MNCs were large monocytoid cells. Serial examination of blood MNCs from one adult with varicella revealed VZV DNA up until 8 weeks, but not 16 weeks, after the appearance of the rash; parallel studies in four zoster patients showed VZV DNA up until 3 weeks, but not later than 7 weeks after the appearance of the rash. These results indicate that MNCs become infected with VZV during the primary encounter with VZV (varicella) and during reactivation (zoster) and that infection continues for weeks after the onset of the skin rash. Furthermore, the detection of VZV DNA in blood MNCs of uncomplicated zoster patients coincides with the period during which these patients experience pain.     

社区新冠疫情防疫人员心理健康状况及影响因素

摘 要：目的：了解上海市高桥社区外来务工子弟小学学生血红蛋白值的变化特征,为制定预防贫血的策略提供参考依 据。方法：以2019学年上海市高桥社区外来务工子弟小学1～4年级所有在校学生为研究对象,分别于2019年6月和2020年 6月对其进行血红蛋白值检测。结果：共检测学生730人,其中男生417人 （57.12%）、女生313人 （42.88%）。男生两次血红 蛋白均值分别为 （128.95±13.72） g/L和 （133.07±13.32） g/L,女生分别为 （126.25±12.33） g/L和 （128.87±12.84） g/L,男生 两次血红蛋白均值均高于女生,差异有统计学意义 （t值分别为8.19和4.33,P值均＜0.05）。7岁组、8岁组、9岁组和10岁 组学生第二次血红蛋白均值均高于第一次,差异均有统计学意义 （t值分别为5.82、3.34、5.53和3.11,P值均＜0.05）。肥胖 组、超重组、正常组、轻度消瘦组、中重度消瘦组学生血红蛋白均值第二次均高于第一次,差异均有统计学意义 （t值分别 为 3.50 、2.94 、7.08 、2.26 和 2.20,P值均＜0.05）。研究对象贫血发病率、恢复率和人群持续率分别为 13.32%、61.48%和 6.44%。女生贫血发病率和人群持续率均高于男生,差异均有统计学意义 （χ2值分别为4.45,4.35,P值均＜0.05）;各年龄组 贫血发病率、恢复率和人群持续率比较,差异均有统计学意义 （χ2值分别为19.91、7.62和12.78,P值均＜0.05）;不同营养 状况学生贫血发病率、恢复率和人群持续率比较,差异均有统计学意义 （χ2值分别为 16.65、5.11和 37.26,P 值均＜0.05）。 结论：应加强对外来务工子弟小学学生的贫血检测工作,干预措施重点实施对象为女生、低年级、消瘦和持续贫血的学生。     

Long-term persistent immunogenicity after successful standard and triple-dosed hepatitis B vaccine in hemodialysis patients: A 3-year follow-up study in China

BackgroundAlthough the efficacy of hepatitis B vaccines among hemodialysis patients has been documented, the long-term persistence of immunogenicity in this population remains largely unknown. We explored the long-term persistence of immunogenicity induced by different hepatitis B vaccine regimens in hemodialysis patients.MethodsIn initial study, we conducted a randomized, multicenter, double-blind, parallel-controlled trial among hemodialysis patients in 13 hospitals in Shanxi Province, China. A total of 352 hemodialysis patients were allocated to receive 3-dose 20 μg (IM20 group) and 3-dose 60 μg (IM60 group) recombinant hepatitis B vaccine at months 0, 1, and 6. Vaccine-induced immune responses were measured at month 7. In this study, the responders (anti-HBs ≥ 10 mIU/mL) were followed up at months 18, 24, 30, 36 and 42, respectively. We used the generalized log-rank test and generalized estimating equations (GEE) to analyze the long-term durability of responses and the kinetics of anti-HBs levels, respectively.ResultsA total of 284 patients were involved in the extended follow-up period. The duration of vaccine-induced response with 75% of patients maintained protective antibody were 12 months and 18 months in the IM20 group and IM60 group, respectively (P = 0.291). The long-term persistent immunogenicity induced by 3-dose 60 μg was more satisfactory than that by 3-dose 20 μg hepatitis B vaccine in patients with hemodialysis duration ≥ five years (P = 0.023). The peak anti-HBs levels in 100–1000 mIU/mL or ≥ 1000 mIU/mL were more likely to maintain long-term protective antibody compared to anti-HBs levels in 10–100 mIU/mL (P ＜ 0.05). The kinetic profile was similar between the two groups (P = 0.334).ConclusionHigh-dose 60 μg hepatitis B vaccine could lead a satisfactory long-term durability of immunogenicity among patients with hemodialysis duration of five years or more. Peak anti-HBs level after vaccination was associated with the long-term persistence of immunogenicity.     

Epidemiology and virulence gene expression of intracellular group A streptococci in tonsils of recurrently infected adults

Intracellularly persistent group A streptococci (GAS, Streptococcus pyogenes) have been associated with recurrent tonsillopharyngitis and antibiotic treatment failure. As a supplementation of the published in vitro data, conventional bacteriology and molecular epidemiology was performed on material from 29 adult patients of a German army hospital with anamnestic signs of recurrent tonsillopharyngitis. Pre-surgery tonsil swabs and the surgically removed tonsils were examined with respect to growth of aerobic bacteria in absence and presence of antibiotics with exclusively extracellular activity. Under such antibiotic selection, Staphylococcus aureus and GAS were cultured from specimens of 13 and 3 patients, respectively. In every material GAS-positive by culture methods, the intracellular location of the penicillin-susceptible GAS isolates was confirmed by immunohistologic examination of tonsillar sections using a GAS-specific IgG antibody. The three intracellular GAS isolates were typed by emm gene sequencing and could be associated to types M6 and M49 (two isolates). The bacteria were serially passaged on sheep blood agar, and semiquantitative mRNA analysis from virulence genes was performed using bacteria of the 4th and 25th passage after isolation. An M-type-specific pattern of virulence gene expression and different gene expression levels in relation to the passage number were observed.     

血源乙型肝炎疫苗免疫持久性观察

为了解血源乙型肝炎（乙肝）疫苗的免疫持久性,对澄江县1991～1995年按照0、1、6个月免疫程序完成血源乙肝疫苗接种的人群,按接种后间隔1～5年分组,每组随机抽取100名儿童,采末梢血,共得517份免疫者的血清样品．用酶联免疫吸附试验（ELISA）检测抗-HBs、HBsAg。结果表明,接种乙肝疫苗2年内抗-HBs阳性率在90％以上,以后随间隔年眼的延长而明显下降,间隔5年降至60％,人群平均保护率达78.57％．