Adenosine A2A receptor deficiency alleviates blast-induced cognitive dysfunction

Traumatic brain injury (TBI), particularly explosive blast-induced TBI (bTBI), has become the most prevalent injury among military personnel. The disruption of cognitive function is one of the most serious consequences of bTBI because its long-lasting effects prevent survivors fulfilling their active duty and resuming normal civilian life. However, the mechanisms are poorly understood and there is no treatment available. This study investigated the effects of adenosine A2A receptor (A2AR) on bTBI-induced cognitive deficit, and explored the underlying mechanisms. After being subjected to moderate whole-body blast injury, mice lacking the A2AR (A2AR knockout (KO)) showed less severity and shorter duration of impaired spatial reference memory and working memory than wild-type mice did. In addition, bTBI-induced cortical and hippocampal lesions, as well as proinflammatory cytokine expression, glutamate release, edema, cell loss, and gliosis in both early and prolonged phases of the injury, were significantly attenuated in A2AR KO mice. The results suggest that early injury and chronic neuropathological damages are important mechanisms of bTBI-induced cognitive impairment, and that the impairment can be attenuated by preventing A2AR activation. These findings suggest that A2AR antagonism is a potential therapeutic strategy for mild-to-moderate bTBI and consequent cognitive impairment.     

Long-term expression of human alpha1-antitrypsin gene in mouse liver achieved by intravenous administration of plasmid DNA using a hydrodynamics-based procedure

The liver is an important target organ for gene transfer due to its large capacity for synthesizing serum proteins and its involvement in numerous genetic and acquired diseases. Previously, we and others have shown that an efficient gene transfer to liver cells in vivo can be achieved by an intravenous injection of plasmid DNA using a hydrodynamics-based procedure. In this study, we systematically characterized the expression of transgene encoding a secretory protein in mouse. Using human alpha1-antitrypsin (hAAT) gene as a reporter, we demonstrate that the serum level of hAAT can reach as high as 0.5 mg/ml by a simple tail vein injection of 10-50 microg plasmid DNA into a mouse. The serum hAAT reaches the peak level 1 day after DNA injection and then declines during the following 2 to 4 weeks to 2-5 microg/ml, a level which persists for at least 6 months. Southern analysis of extracted DNA and RT-PCR analysis of RNA from the liver reveal that hAAT gene is active and present as episomal form after 6 months. These results suggest that the hydrodynamics-based transfection procedure provides a valuable tool for screening genes for therapeutic purposes in whole animals.     

鼠胚成纤维细胞的培养条件及滋养层制备

背景:鼠胚成纤维细胞经丝裂霉素C处理或Y射线照射阻断其有丝分裂后,铺层的细胞可保持活力但不增殖,并能够在生长过程中产生促进胚胎十细胞生长的因子和抑制胚胎干细胞分化的因子,但其生命期有限.目的:探讨分离小鼠胚胎成纤维细胞的最适胚龄与培养条件,以及用其制备细胞饲养层的效果.设计、时间及地点:细胞学体外观察,于2005-11/2006-07在广东省计划生育专科医院实验室完成.材料:清洁级昆明系孕7.5,10.5,13.5,16.5,19.5 d雌鼠各5只.方法:无菌取上述各孕龄小鼠胚胎分离鼠胚成纤维细胞,调整细胞浓度为1×107L-1、1×109L-1 1×1011 L-1,胰酶消化传代.当胚胎成纤维细胞生长并相互接触时,加入丝裂霉素C作用2-4 h,用无钙无镁PBS配制的胰蛋白酶液消化2～5 min,终止后用吸管吹打皿底,使细胞充分分离,以含10%胎牛血清的DMEM液调整细胞浓度为5×108 L-1,将该悬液移入明胶处理的培养皿内常规培养,制备鼠胚成纤维细胞饲养层.主要观察指标:胎龄、细胞浓度、传代次数对鼠胚成纤维细胞生长增殖的影响.不同胎龄鼠胚成纤维细胞饲养层制备效果.结果:7.5～19.5 d鼠胚均可分离出成纤维细胞,但7.5 d.10.5 d鼠胚分离所得成纤维细胞数最少,寿命短,且混有大量杂细胞:13.5d鼠胚分离所得成纤维细胞数量多,增殖快,所含杂细胞少:16.5～19.5 d鼠胚分离所得成纤维细胞生长状态不良,增殖缓慢,杂细胞较多.同等条件下与1x107 L-1、1×1011 L-1浓度比较,1×109 L-1浓度的鼠胚成纤维细胞生长状况良好,铺层时间适中,细胞寿命最长(P＜0.05).以13.5 d鼠胚成纤维细胞经初代培养后传4代,成功建立了成纤维细胞株,相同条件下1～代细胞形态,体积、生长状况无明显差别.7.5～19.5 d鼠胚成纤维细胞制备的饲养层,铺层时间基本相似(P＜0.05),细胞寿命均可维持一二周.结论:分离小鼠胚胎原代成纤维细胞的最适胎龄及细胞浓度分别为13.5d与1×109 L-1,4代以内传代次数不影响鼠胚成纤维细胞的生长增殖,且不同胎龄所制备的饲养层细胞寿命无差别.     

Progress in brain penetration evaluation in drug discovery and development

This review discusses strategies to optimize brain penetration from the perspective of drug discovery and development. Brain penetration kinetics can be described by the extent and time to reach brain equilibrium. The extent is defined as the ratio of free brain concentration to free plasma concentration at steady state. For all central nervous system (CNS) drug discovery programs, optimization of the extent of brain penetration should focus on designing and selecting compounds having low efflux transport at the blood-brain barrier (BBB). The time to reach brain equilibrium is determined by both BBB permeability and brain tissue binding. Rapid brain penetration can be achieved by increasing passive permeability and reducing brain tissue binding. Although many drug transporters have been identified at the BBB, the available literature demonstrates only the in vivo functional importance of P-glycoprotein (P-gp) in limiting brain penetration of its substrates. Drug-drug interactions mediated by P-gp at the BBB are possible due to inhibition or induction of P-gp. For newly identified drug transporters at the BBB, more research is needed to reveal their in vivo significance. We propose the following strategies for addressing drug transporters at the BBB. 1) Drug discovery screens should be used to eliminate good P-gp substrates for CNS targets. Special consideration could be given to moderate P-gp substrates as potential CNS drugs based on a high unmet medical need and the presence of a large safety margin. 2) Selection of P-gp substrates as drug candidates for non-CNS targets can reduce their CNS-mediated side effects.     

连续性血液净化治疗重症急性肾功能衰竭患者的护理

目的观察连续性血液净化(CBP)治疗重症急性肾功能衰竭(ARF)的临床疗效和对预后的影响,评价护理方法的作用。方法对2000年以来入我院ICU的13例ARF(伴发多器官功能障碍综合征,MODS)病人进行CBP治疗的临床资料进行回顾性分析,观察血管通路的护理、抗凝方法的选用、液体平衡的管理、监测生命体征等护理方法在治疗中的作用。结果9例患者经CBP治疗24小时后,生命指征平稳,BUN、Scr下降(P<0.05),CO2CP正常,87～240小时后进入多尿期;4例患者死于严重创伤或多器官功能衰竭(MOF)。治疗过程中无持续低血压和低体温等并发症。结论对重症ARF的患者应用CBP治疗,血液动力学稳定,溶质清除率高,有利于营养支持及清除炎性细胞因子,从而改善重症ARF患者的预后;正确的护理方法在其中起到重要的作用。     

大连市心脑血管疾病患者与健康者血硒水平的比较

背景:硒是人体必需的微量元素之一,是具有抗氧化功能的硒酶的活性中心,能清除体内的自由基,有效地催化有害的过氧化物还原为无害的羟基化合物,增强人体免疫力,预防和治疗心脑血管疾病和癌症。目的:比较心脑血管疾病患者血硒水平与健康者的差别,以期对心脑血管疾病的预防和治疗提供依据。设计:病例-对照分析。单位:大连铁路卫生学校,大连铁路医院,大连铁道学院应化系。对象:采集2000-03/2001-05大连铁路医院收治的心脑血管疾病患者血样319份。319例患者中男169例,女150例;高血压164例,冠状动脉粥样硬化性心脏病97例,心律失常41例,脑血管意外17例。健康组300例为同期健康体检者,男159例,女141例。方法:用新极谱法测定心脑血管疾病患者血样的血硒水平。主要观察指标:①两组受试者血硒的总体水平。②不同性别血硒水平比较。③患者组不同病种间血硒水平比较。结果:619例受试者全部进入结果分析。①患者组总体血硒水平低于健康组[(114.0±52.5),(146.5±51.0)μg/L,P<0.001],仅为健康人的76%。②男性与女性血硒含量的概率分布均为正态分布,男女之间差异无显著性意义(P>0.10),但血硒水平女性略高于男性。③高血压、冠状动脉粥样硬化性心脏病、心律失常患者血硒水平相当于健康组的82.7%,68.6%,66.0%,但男女之间差异不显著(P>0.10)。脑血管意外患者的血硒水平最低,为(84.4±28.9)μg/L,仅是健康人的57.6%。结论:心脑血管疾病患者血硒水平低于健康人,应适量补充有机硒和无机硒。     

Clinical features in a large Iranian family with a limb-girdle congenital myasthenic syndrome due to a mutation in DPAGT1

Mutations in DPAGT1 are a newly recognised cause of congenital myasthenic syndrome. DPAGT1 encodes an early component of the N-linked glycosylation pathway. Initially mutations in DPAGT1 have been associated with the onset of the severe multisystem disorder – congenital disorder of glycosylation type 1J. However, recently it was established that certain mutations in this gene can cause symptoms restricted to muscle weakness resulting from defective neuromuscular transmission. We report four cases from a large Iranian pedigree with prominent limb-girdle weakness and minimal craniobulbar symptoms who harbour a novel mutation in DPAGT1, c.652C>T, p.Arg218Trp. This myasthenic syndrome may mimic myopathic disorders and is likely under-diagnosed.     

Clinical features and management of intracranial subependymomas in children

Subependymoma is a rare low-grade glioma of the central nervous system that occurs most commonly in middle-aged and elderly men and rarely in children. Only a few paediatric patients with subependymomas have been reported. The authors retrospectively analysed five paediatric patients (4 males and 1 female; mean age 8.6 years; age range 5–13 years) at a single institute from July 1998 to April 2009 and summarised the clinical characteristics and management of paediatric intracranial subependymoma. The most common symptom in these five paediatric patients with subependymoma was intracranial hypertension. The tumours were located in the fourth ventricle in two patients, in the fourth ventricle with extension to the cerebellopontine angle (CPA) in one patient; in the right CPA exclusively in one patient, and intraparenchymally in the left parietal lobe in one patient, the latter two of which are rare locations for subependymoma. Surgery was performed on all five patients. The surgical approach was selected as appropriate for the tumor location. Total resection was achieved in three patients, and subtotal resection in two. All five patients had good outcomes without recurrence. We conclude that surgery is the optimal therapy for paediatric patients with intracranial subependymoma.