Clinical outcome of Burkholderia cepacia complex infection in cystic fibrosis adults.

BACKGROUND: The Burkholderia cepacia complex (BCC) is one of the most important groups of organisms infecting cystic fibrosis (CF) patients. The aim of the study was to examine how infection with BCC affects clinical outcome. METHODS: Nineteen CF adults infected with BCC and 19 controls infected with Pseudomonas aeruginosa were studied over a 4-year period. The best forced expiratory volume in 1 s (FEV(1)) and body mass index (BMI) for each year were recorded and annual rate of decline calculated. RESULTS: The BCC infected group displayed a significantly greater reduction of FEV(1) and BMI compared to the P. aeruginosa infected group (p=0.001 and p=0.009, respectively). Sixteen patients infected with a single Burkholderia cenocepacia strain had a significantly greater rate of FEV(1) decline compared to those infected with Burkholderia multivorans (n=3) or P. aeruginosa (p=0.01 and p<0.0001, respectively). The rate of BMI decline was significantly greater in patients infected with B. cenocepacia compared to those with P. aeruginosa (p=0.007), but not significantly different in those with B. multivorans (p=0.29). CONCLUSION: BCC infection is associated with an accelerated decline in pulmonary function and BMI. Infection with a single B. cenocepacia strain was associated with a more rapid decline in lung function than those infected with either B. multivorans or P. aeruginosa.     

Airway persistence by the emerging multi‐azole‐resistant Rasamsonia argillacea complex in cystic fibrosis

Infections caused by Rasamsonia argillacea complex have been reported in various clinical settings. Cystic fibrosis (CF) is one of the main underlying conditions. An observational cohort study of CF patients with Rasamsonia in respiratory samples was conducted. Eight isolates from 6 patients were identified as R. argillacea complex and tested for antifungal susceptibility. All isolates had high MICs to voriconazole and posaconazole and low MECs to echinocandins. Four patients experienced lung function decline in the year preceding first Rasamsonia isolation. This continued in the year following first isolation in 3 out of 4 cases. Antifungal therapy was initiated in 2 patients, to which only one exhibited a clinical response. Three out of 6 patients died within 3 years of isolating Rasamsonia. Genotyping suggests that similar genotypes of Rasamsonia can persist in CF airways. Consistent with other fungi in CF, the clinical impact of airway colonisation by Rasamsonia is variable. In certain patients, Rasamsonia may be able to drive clinical decline. In others, though a clear impact on lung function may be difficult to determine, the appearance of Rasamsonia acts as a marker of disease severity. In others it does not appear to have an obvious clinical impact on disease progression.     

B-cell influences on the induction of allotype suppressor T cells

Allotype suppressor T-cell (Ts) populations that persist for the life of the animal arise in (BALB/c × SJL)F(1) hybrids exposed perinatally to antibody to the paternal (Ig-1b) allotype on IgG(2a)-isotype immunoglobulin H chains. These Ts suppress Ig-lb production by depleting the supply of allotype- specific helper T cells (Th) required, in addition to carrier-specific Th, for the latter stages of Ig-1b memory B-cell differentiation. In this publication, we show that specific Ig-1 allotype Ts are induced by perinatal exposure to antisera which interfere with normal B-cell maturation, i.e., by antibodies reactive with surface IgM on immature precursors of IgG(2a), memory cells. Antibodies to IgM (Ig-6) allotypes carried on precursors induce specific suppression for the IgG2, allotype produced by progeny of the target precursor. Anti-Ig-6a and anti-Ig-6b induce Ts that specifically suppress Ig-1a and Ig-1b, respectively. Heterologous (goat) anti-IgM induces suppression for both IgG(2a) immunoglobulins (Ig-1a and Ig-1b). Ts activity in these antiprecursor-Ig-suppressed mice is expressed in adoptive transfer assays and, as with anti-Ig-1b-induced Ts, is rendered ineffective by cotransfer of adequate numbers of T cells but not B cells from nonsuppressed mice. The Ts induction, in contrast with Ts expression, is reversed by the introduction of appropriate adult B-cell populations from nonsuppressed donors. Taken together, these data suggest that the development of mature B cells plays a central role in the early establishment of the balance between helper cells and suppressor cells that determines whether Ts or Th will dominate in regulating Ig-1b production in adult animals.     

壳聚糖/肝素和壳聚糖/重组水蛭素共价包被镍钛合金片的体外生物相容性

目的:体外评价生物活性分子共价包被镍钛金属片后的生物相容性。方法:实验于2005-11/2006-10在南京医科大学心血管药理实验室完成。实验材料:镍钛合金片(镍含量55.3%～55.6%,钛含量43.5%～44.2%,厚度0.05cm,激光切割为0.5cm×0.5cm);壳聚糖(脱乙酰度90%,Mr200000);肝素、重组水蛭素。实验分组:①实验分4组:未包被组、壳聚糖组、壳聚糖/肝素组、壳聚糖/重组水蛭素组。将壳聚糖、肝素(1g/L)和重组水蛭素(20mg/L)用共价化学交联法包被于镍钛金属片单面。②溶血实验:将各组样品加0.2mL稀释血液和10mL生理盐水。阳性对照和阴性对照分别用10mL蒸馏水和10mL生理盐水各加0.2mL稀释血,与样品同样操作。③人全血动态接触实验:各组镍钛合金片分别放入10mL新鲜的人全血后行扫描电镜检查,并检测血常规(红细胞计数、白细胞计数、血小板计数)及凝血3项(部分凝血活酶活化时间、凝血酶原时间、凝血酶时间)。④内皮细胞种植、培养:人脐静脉内皮细胞培养、传代后,植入每孔已放入1片镍钛金属片的24孔板中,倒置显微镜下观察人脐静脉内皮细胞生长情况及细胞形态。⑤免疫荧光标记:Fn免疫荧光染色(红色激发波长510nm)观察细胞生长和黏附情况,Ki67免疫荧光标记(绿色激发波长510nm)观察细胞增殖情况。实验评估:①各组血液样本溶血率。②各组人全血接触实验后血液样本血细胞计数和凝血活性。③扫描电镜下各组人全血接触实验后镍钛金属片表面形态。④倒置显微镜下人脐静脉内皮细胞形态。⑤荧光显微镜下镍钛金属片表面人脐静脉内皮细胞生长、黏附情况。⑥荧光显微镜下镍钛金属片表面人脐静脉内皮细胞增殖情况。结果:①溶血率:各组镍钛金属片溶血率均小于1.7%。②血细胞计数和凝血活性:各组接触血液后红细胞、白细胞和血小板计数与未接触血液无差别;壳聚糖/重组水蛭素组与壳聚糖/肝素组部分凝血活酶活化时间、凝血酶原时间和凝血酶时间值较未包被组和壳聚糖组明显延长,差异有显著性意义(P<0.001);壳聚糖/重组水蛭素组部分凝血活酶活化时间和凝血酶时间值较壳聚糖/肝素组延长,差异有显著性意义(P<0.005)。③扫描电镜下各组人全血接触实验后镍钛金属片表面形态:镍钛合金片表面有纤维蛋白黏附、血小板黏附和聚集,顺序依次为壳聚糖组>未包被组>壳聚糖/肝素组>壳聚糖/重组水蛭素组。④倒置显微镜下人脐静脉内皮细胞形态:与人脐静脉内皮细胞72h孵育,见各组镍钛金属片边缘细胞生长、移行良好,无细胞变形。⑤荧光显微镜下镍钛金属片表面人脐静脉内皮细胞生长、黏附情况:利用Fn免疫荧光标记人脐静脉内皮细胞,镍钛金属片表面的人脐静脉内皮细胞黏附和生长顺序如下:壳聚糖组>未包被组>壳聚糖/重组水蛭素组>壳聚糖/肝素组。⑥荧光显微镜下镍钛金属片表面人脐静脉内皮细胞增殖情况:利用Ki67免疫荧光标记人脐静脉内皮细胞,镍钛金属片表面的人脐静脉内皮细胞增殖顺序如下:壳聚糖组=未包被组>壳聚糖/重组水蛭素组>壳聚糖/肝素组。结论:壳聚糖/肝素与壳聚糖/重组水蛭素包被镍钛金属后具有良好抗凝血活性,但壳聚糖/重组水蛭素与壳聚糖/肝素相比更有利于人脐静脉内皮细胞的生长。     

大鼠海马神经细胞体外缺糖缺氧模型制备方法的改进

目的:改进培养大鼠海马神经细胞体外缺糖缺氧模型制备方法,并通过兴奋性氨基酸N-甲基-D-天冬氨酸受体拮抗剂进行验证。方法:实验于2004-09/2005-06在南方医科大学基础医学院神经生物学教研室进行。实验材料:出生1d内清洁级SD大鼠,由南方医科大学实验动物中心提供(合格证号为粤证监字2004B023号)。N-甲基-D-天冬氨酸受体拮抗剂5-甲基二氢丙环庚烯亚胺马来酸(MK-801)和D-2-氨基-5-磷酰基戊酸(d-APV)购自Sigma公司。实验方法:取新生1dSD大鼠海马组织作神经细胞分散细胞原代培养,培养到13d时进行氧/葡萄糖剥夺模型的制备:将neurobasal培养基更换为不含葡萄糖的BSSo培养基,连续充以50mL/LCO2 950mL/LN2(体积比)混合气体。缺氧30,45,60,90min后取出细胞,更换为正常neurobasal培养基,恢复正常条件继续培养。将神经细胞随机分为正常对照组、单纯缺氧组、无糖缺氧组、MK-801组和d-APV组。将10μmol/LMK-801和500μmol/Ld-APV在通50mL/LCO2 950mL/LN2混合气前加入到BSSo培养基,缺氧结束后随BSSo培养基一起去掉。复氧24h后采用MTT比色法测神经细胞成活率及Hoechst荧光染料法测神经细胞凋亡率。结果:①随着氧/葡萄糖剥夺时间延长,神经细胞存活率下降。氧/葡萄糖剥夺30,45,60,90min再复氧24h,神经细胞存活率分别为(81.48±3.84)%、(63.14±3.14)%、(41.73±2.97)%和(16.78±2.12)%。②N-甲基-D-天冬氨酸受体拮抗剂MK-801(10μmol/L)和d-APV(500μmol/L)均能明显增加神经细胞存活率(P<0.05),并且两组细胞存活率与正常对照组比较,差异无统计学意义(P>0.05)。结论:实验制备的海马神经细胞短时间氧/葡萄糖剥夺模型可对神经细胞造成迟发性死亡,兴奋性氨基酸N-甲基-D-天冬氨酸受体拮抗剂可保护氧/葡萄糖剥夺诱导的神经细胞损伤,说明本实验建立的缺氧模型有效并简便可靠,并且缩短了缺氧时间。