Pediatric pneumococcal bone and joint infections. The Pediatric Multicenter Pneumococcal Surveillance Study Group (PMPSSG)

OBJECTIVE: To describe the clinical and microbiological characteristics of infants and children with bone and joint infections caused by penicillin-susceptible and penicillin-nonsusceptible strains of Streptococcus pneumoniae. DESIGN: Multicenter, prospective patient accrual; retrospective chart review of identified patients. SETTING: Eight children's hospitals in the United States. PARTICIPANTS: Forty-two children with bone and/or joint infections prospectively enrolled in the United States Pediatric Multicenter Pneumococcal Surveillance Study from September 1, 1993 to August 31, 1996. OUTCOME MEASURES: Data were collected on multiple variables, including age, gender, race, days of symptoms before and during hospitalization, antibiotic and surgical therapy, laboratory and imaging studies. RESULTS: Of the 42 children enrolled (21 bone, 21 joint infections), 14 had isolates that were not susceptible to penicillin. Eight of 16 (50%) strains isolated from children who received antibiotics within 4 weeks before hospitalization were not susceptible to penicillin, compared with 4 of 15 (27%) strains isolated from children without previous antibiotic exposure. Clinical response to therapy was similar between children infected by penicillin-susceptible strains compared with those infected by penicillin-nonsusceptible strains, including duration of hospitalization (9.1 days vs 11.2 days), days of intravenous antibiotic therapy (25.3 days vs 24.6 days), days of fever (3.6 days vs 3.1 days), and sequelae (14% vs 7%). The most commonly prescribed single agents for parenteral therapy in definitive treatment were ceftriaxone (36%), penicillin (15%), and clindamycin (15%). Oral therapy followed parenteral therapy in 56% of children. The mean (+/- standard deviation) duration of total antibiotic therapy in children with osteomyelitis was 57.5 +/- 48.6 days (range, 23-196 days) and 29.2 +/- 11.8 days (range, 12-67 days) for arthritis. Late sequelae (long-term destructive changes of the bone or joint) were documented in 5 (12%) children, 4 with osteomyelitis, and 1 with arthritis. Sequelae occurred in 30% of children with long bone osteomyelitis associated with infection in the adjacent joint. The age of children with sequelae was younger than those without sequelae (6.4 months vs 18.6 months). CONCLUSIONS: The demographic characteristics and anatomic sites of infection in our patients were similar to previously published series collected from single institutions before the emergence of significant antibiotic resistance in S pneumoniae. Our analysis suggests that children infected by penicillin-nonsusceptible strains have a similar clinical response to therapy when compared with children infected by penicillin-susceptible strains.     

三维多孔β-磷酸三钙支架与骨髓基质细胞构建组织工程骨的生物相容性及显微形态学观察

目的:定量及显微观察三维多孔β-磷酸三钙支架在构建组织工程骨时的组织相容性。方法:实验于2002-07/2005-07在第四军医大学口腔医学院颌面外科组织工程实验室完成。将兔的骨髓基质细胞,按一定量分置在培养板的各孔内,将多孔β-磷酸三钙支架材料置入孔内共培养,采用MTT法和碱性磷酸酶试剂盒检测骨髓基质细胞活性,共聚焦显微镜观察其在β-磷酸三钙支架表面的微观形态。结果:①倒置显微镜下观察接种前的细胞形态基本均匀一致。②接种后6d扫描电镜观察显示,材料表面可见较多细胞和细胞合成的丝状细胞外基质。③细胞接种后6d激光共聚焦显微镜观察显示,细胞数量明显增多,基本长满材料的表面,同时在孔隙中,也有大量细胞长入。④β-磷酸三钙对骨髓基质细胞的增殖作用:培养第5天,β-磷酸三钙组对骨髓基质细胞的增殖作用(A)低于对照组,差异有显著性意义(分别为0.47±0.02,0.52±0.02,t=2.281,P<0.05)。⑤β-磷酸三钙对骨髓基质细胞的碱性磷酸酶的活性比较:在骨髓基质细胞诱导培养5,7,9d,β-磷酸三钙组碱性磷酸酶的活性(A)明显低于对照组,差异有显著性意义(分别为5.18±0.31,6.05±0.54;12.35±0.62,14.17±0.70;15.68±0.87,17.13±1.14,t=3.302,6.025,6.019,P<0.05)。结论:三维多孔β-磷酸三钙支架有良好的组织相容性,为其应用于临床提供了可靠的实验依据。     

How to determine life expectancy change of air pollution mortality: a time series study

Background  

Information on life expectancy (LE) change is of great concern for policy makers, as evidenced by discussions of the "harvesting" (or "mortality displacement") issue, i.e. how large an LE loss corresponds to the mortality results of time series (TS) studies. Whereas loss of LE attributable to chronic air pollution exposure can be determined from cohort studies, using life table methods, conventional TS studies have identified only deaths due to acute exposure, during the immediate past (typically the preceding one to five days), and they provide no information about the LE loss per death.     

Impaired humoral response to vaccines among HIV-exposed uninfected infants

Little is known about the vaccine protective response for infants born from HIV-infected mothers. We evaluated the antibody response to hepatitis B, tetanus, and diphtheria vaccine in vertically HIV-exposed uninfected infants and compared them to those of control infants not exposed to the virus. The quantitative determination of specific neutralizing antibodies against hepatitis B, diphtheria, and tetanus were performed blindly on serum samples. The results showed that 6.7% of the HIV-exposed uninfected individuals were nonresponders to hepatitis B vaccine (anti-HBs titer, <10 mIU/ml), and 64.4% were very good responders (anti-HBs titer, ≥1,000 mIU/ml), whereas only 3.6% of the nonexposed infants were nonresponders (χ(2)=10.93; 1 df). The HIV-exposed uninfected infants showed protective titers for diphtheria and tetanus but lower geometric mean anti-tetanus titers compared to those of the HIV-unexposed infants. Our data point to the necessity of evaluating vaccine immune responses in these children and reinforced that alterations in lymphocyte numbers and functions reported for newborns from HIV-infected mothers interfere with the vaccine response.     

Impact of delayed admission to intensive care units on mortality of critically ill patients: a cohort study

Introduction  

When the number of patients who require intensive care is greater than the number of beds available, intensive care unit (ICU) entry flow is obstructed. This phenomenon has been associated with higher mortality rates in patients that are not admitted despite their need, and in patients that are admitted but are waiting for a bed. The purpose of this study is to evaluate if a delay in ICU admission affects mortality for critically ill patients.     

同种异体胚胎神经干细胞移植修复脊髓损伤的时效性观察

目的:观察同种异体胚胎神经干细胞移植对脊髓损伤大鼠双后肢运动功能的修复作用,并分析其移植时效性。方法:实验于2003-07/08在大连医科大学分子生物学实验室和大连理工大学环境与生命学院生物医学实验室完成。①取孕14￣16d的大白鼠1只,引颈处死,剖腹,取出胎鼠,钳取大脑皮质及皮质下脑室旁的脑组织,体外培养大鼠胚胎神经干细胞。②将30只成年SD大鼠按随机数字表法分为3组,即损伤对照组、早期移植组和延期移植组,每组10只。3组大鼠均制作脊髓横断损伤模型,造成大鼠下肢瘫痪,早期移植组、延期移植组大鼠分别在伤后3d及3周移植胎鼠脑组织神经干细胞。观察移植后大鼠双后肢的运动功能恢复情况,通过胶质原纤维酸性蛋白及神经元特异性烯醇化酶免疫组化染色法观察各组大鼠的脊髓组织形态学变化,胶质原纤维酸性蛋白是星形胶质细胞特异性标志蛋白,神经元特异性烯醇化酶是神经元特异性蛋白。结果:脊髓损伤建模实验纳入大鼠30只,全部进入结果分析,无脱失。①各组大鼠神经干细胞移植后双后肢的功能恢复情况:早期移植组和延期移植组大鼠双后肢的运动功能均有明显改善,但早期移植组表现尤为显著。早期移植组和延期移植组细胞移植后五六天即可见瘫痪大鼠的后肢肌力开始恢复,二三周后可出现爬行,4周后后肢活动活跃;损伤对照组大鼠的瘫痪肢体无任何恢复。②移植4周后早期移植组大鼠移植区脊髓组织的形态学变化:脊髓移植区肉眼可见有增生的组织充填,镜下有大量新生的细胞,表现为神经元和神经胶质细胞阳性染色(胶质原纤维酸性蛋白( ),神经元特异性烯醇化酶( ))。结论:神经干细胞移植对脊髓横断大鼠运动功能恢复有促进作用,早期移植疗效更好。