神经短肽NAP在缺氧环境中对体外小鼠Müller细胞的保护作用

目的:观察神经短肽NAP对小鼠Mller细胞在缺氧环境中的保护作用。方法:用重组腺相关病毒作为载体,将含NT4-NAP融合基因的rAAV-NAP和含报告基因的rAAV-GFP对体外培养的小鼠Mller细胞进行感染,用MTT法和流式细胞仪检测感染细胞和未感染细胞在缺氧24h时的增殖活性和凋亡率。结果:感染rAAV-GFP的小鼠Mller细胞表达出明显的绿色荧光,缺氧24h时,感染rAAV-NAP的细胞与未感染细胞相比,增殖活性高(A=0.109,P<0.05),两组细胞凋亡率分别为8.13%和18.72%,感染有NAP细胞的凋亡率显著低于正常细胞(P<0.05)。结论:神经短肽NAP可以减轻缺氧对Mller的损害。     

可分泌表达神经保护肽的重组慢病毒对闭合性脑损伤小鼠的神经保护作用

目的：通过滴鼻给药途径,给予闭合性脑损伤小鼠可分泌表达神经保护肽NAP的重组慢病毒,观察该重组病毒经鼻-脑通路对中枢神经系统的保护作用,为携带可分泌表达NAP的重组慢病毒治疗神经系统退行性疾病提供理论依据。 方法：选用8~12周成年雄性昆明小鼠54只,随机分为4组：空白对照组10只（Control组）、重锤加害组20只（CHI组）、重组慢病毒rLent/NT4-NAP保护组20只（rLent组）和重组慢病毒rLent/GFP组4只（GFP组）。观察各组小鼠的死亡率、神经功能损伤（NSS）评分、脑水肿含量和病理改变情况。应用共聚焦显微镜观测GFP组小鼠鼻黏膜、嗅神经和脑组织内绿色荧光表达情况。 结果：rLent组小鼠死亡率（15％）明显低于CHI组小鼠（55％）;rLent组小鼠NSS评分在创伤后1、3、5和7 d均显著低于CHI组（P<0.01）; rLent组小鼠创伤后24 h的脑水肿含量明显低于CHI组（P<0.01）;HE染色显示rLent组小鼠病理改变明显轻于CHI组;GFP组仅在鼻黏膜处可见呈条索样的绿色荧光,而在嗅神经及大脑则未发现绿色荧光。 结论：分泌表达NAP的重组慢病毒可感染鼻黏膜细胞,分泌表达的短肽NAP能够改善闭合性脑损伤小鼠的神经功能;未加装分泌表达元件的重组病毒rLent/GFP仅能感染鼻黏膜细胞,不能通过血脑屏障进入中枢神经系统。     

Ameliorative effect of NAP on laser‐induced retinal damage

Purpose: NAP is the smallest active element of activity‐dependent neuroprotective protein (ADNP) in the non‐myelinated neural tissue. This study evaluated the neuroprotective effect of NAP in reducing the spread of laser‐induced retinal damage in rat. Methods: Laser lesions were created in 72 DA pigmented rats. Two groups were treated by one intravenous or intravitreal injection of NAP immediately after exposure to laser. Two control groups were similarly administered saline injection. Histological and morphometrical evaluations of the lesions were preformed 3, 20 and 60 days after photocoagulation. Results: After intravitreal treatment with NAP, a significant reduction in the diameter of the laser‐induced lesions was found 3 days after photocoagulation (p < 0.001) but not after 20 and 60 days while the systemic treatment significantly reduced lesion diameter 20 and 60 days after photocoagulation (p = 0.001). Significant difference in photoreceptor cell loss was found in eyes treated intravitreally only 3 days after photocoagulation (p = 0.002). In the systemically treated animals such effect was found only after 20 and 60 days (p < 0.001). Conclusions:  Treatment with NAP ameliorates laser‐induced retinal lesions. Intravitreal treatment had an early short‐term effect while the effect of systemic administration was delayed and prolonged. This treatment may be of clinical significance in reducing laser‐induced retinal injuries in humans.     

Susceptibilities of drugs to nitrosation under simulated gastric conditions

Drugs of differing structures and pharmacological actions have been incubated at 37 degrees C and pH 2.0 under conditions simulating those within the normal fasting stomach. The nitrite concentration (25 microM) was kept as constant as possible for 3 hr in an attempt to mimic its in vivo replenishment from the saliva. The extents of N-nitrosation varied widely, but were less than those observed by Gillatt et al. (Fd Chem. Toxic. 1984, 22, 269) using the WHO Nitrosation Assay Procedure, in which the initial nitrite concentration is 40 mM, 1600 times greater, and the pH (3.0) is close to the optimum for the N-nitrosation of secondary amines. The highest yield of N-nitroso compound was obtained with the benzathine salt of penicillin G whereas some drugs, including hydrochlorothiazide and chlorthalidone, produced no detectable N-nitroso derivative. The degree of N-nitrosation was consistently reduced when the initial nitrite concentration of 25 microM was not replenished during the incubations, underlining the importance of simulating the continuous supply of nitrite from the saliva. In all instances, the reactions of the drugs with nitrous acid were inhibited and, in most cases, completely prevented by the presence of ascorbic acid (125 mg).     

Clostridium difficile in paediatric populations

An increase in Clostridium difficile infection incidence has been observed among hospitalized children in the United States. The present statement, targeted at clinicians caring for infants and children in community and institutional settings, summarizes the relevant information relating to the role of C difficile in childhood diarrhea and provides recommendations for diagnosis, prevention and treatment. Significant differences between adult and paediatric risk factors and disease are discussed, along with emerging therapies. The relationship between age and disease severity in children with a newly emergent and more fluoroqinolone-resistant strain of C difficile (North American Pulse-field type-1 [NAP1]) remains unknown. The importance of antimicrobial stewardship as a preventive strategy is highlighted. This statement replaces a previous Canadian Paediatric Society position statement on C difficile published in 2000.     

NF-κB 激活蛋白2(NAP2)诱导白细胞介素-12分泌的研究

目的：研究新克隆的编码NF—κB激活蛋白2(NAP2)基因的功能及作用机制。方法：采用NF-κB和IL—12启动子荧光素酶报告质粒及胞质内IL—12染色法，观察NAP2基因产物在巨噬细胞中对NF—κB、IL—12启动子的激活及对IL-12合成的调控。结果：NAP2可激活NF—κB和IL—12启动子，而IκBαDN则可抑制他们的活化。在巨噬细胞系J774中，NAP2也可诱导IL—12表达。结论：NAP2基因产物可激活IL—12启动子并诱导IL—12的合成，提示NAP2可能是通过调控NF—κB转录因子而调节IL—12的表达。     

In vitro susceptibility to 17 antimicrobials of clinical Clostridium difficile isolates collected in 1993–2007 in Sweden

This study investigated the MICs of 17 antimicrobials, for 606 toxigenic clinical isolates of Clostridium difficile collected between 1993 and 2007 in Sweden. Low MIC₉₀ values were found for metronidazole (0.5 mg/L), vancomycin (1.0 mg/L), teicoplanin (0.125 mg/L), fusidic acid (1.0 mg/L), linezolid (2.0 mg/L), daptomycin (2.0 mg/L) and tigecycline (0.064 mg/L). Three isolates (0.5%) had elevated MICs for vancomycin (4–8 mg/L); however, these isolates originated from the same patient, who was receiving long-term intravenous vancomycin treatment. High-level clindamycin resistant isolates (MIC >256 mg/L) peaked in 1997 with 39 of 95 (41%) and out of these, 36% were also highly resistant to erythromycin. β-Lactams such as penicillin V and piperacillin displayed MIC₉₀s of 8 and 32 mg/L, respectively, whereas MICs of cefuroxime were >256 mg/L for all isolates. Universal resistance to ciprofloxacin and levofloxacin was found, and resistance to moxifloxacin increased from 4% of isolates in 2004 to 23% in 2007. Notably, these moxifloxacin-resistant isolates did not belong to the recent epidemic PCR ribotype 027, but to the pre-existing epidemic type 012 (82%), and these isolates accounted for the majority of isolates that were resistant to clindamycin (70%), tetracycline (84%) and rifampicin (92%) as well. This investigation of susceptibility data on clinical C. difficile isolates showed variations of multiresistance to be due to a specific PCR ribotype 012, emphasizing the importance of genotyping when evaluating emerging resistance over time.     

表达幽门螺杆菌NAP基因的减毒沙门菌疫苗株的建立

目的：建立表达幽门螺杆菌(H．pylori)中性粒细胞活化蛋白(Hp—NAP)的减毒沙门菌疫苗株。方法：用PCR扩增Hp—NAP基因，并克隆至原核表达质粒pTrc99A中，经PCR及酶切鉴定后测定其基因序列，并与GenBank中相关序列的同源性进行比较。以重组质粒pTrc99A—NAP转化减毒伤寒沙门菌SL3261，培养后筛选阳性菌落，抽提质粒进行PCR及酶切鉴定。表达的Hp—NAP蛋白用SDS—PAGE进行鉴定，用薄层扫描分析蛋白含量。结果：核苷酸序列测定及同源性分析证实，克隆的Hp—NAP基因与GenBank中相关序列的同源性为98％(397／402)，氨基酸序列的同源性为98％(131／133)。以重组质粒pTrc99A—NAP转化的减毒沙门菌，可表达Mr约15000的Hp—NAP蛋白，表达量约占菌体蛋白量的37．5％。结论：建立了可表达Hp—NAP基因的减毒鼠伤寒沙门疫苗株，为进一步研制Hp口眼疫苗奠定了基础。