自主呼吸试验通过后拔管失败原因分析

目的:分析通过自主呼吸试验(SBT)后拔管失败的原因,提高撤机拔管的成功率。方法:回顾性分析重症监护病房(ICU)接受机械通气并通过SBT后拔管的126例患者的临床资料及其拔管失败原因。结果:拔管失败28例(22.22%),因呼吸系统原因导致拔管失败15例,其中气道分泌物过多且喘憋加重14例,呼吸骤停1例;低氧血症7例;呼吸性酸中毒3例,其中喉水肿1例,支气管狭窄1例;意识障碍加重3例,其中脑出血1例。拔管失败患者中,血白蛋白水平是拔管失败后患者病死率的保护因素。结论:仅通过SBT来指导撤机拔管可能有一定的局限性,除了呼吸系统原因外,氧合状态、中枢神经系统、营养状态等都可能对拔管结局产生影响,因此对于通过SBT进行脱机拔管的患者,仍应该充分评估呼吸道、中枢神经、心功能以及营养状态等多方面因素。     

Characterization of rpoB mutations in rifampicin-resistant Mycobacterium tuberculosis isolated in China

The objective of this study was for the elucidation of the characteristics of the rpoB gene mutation in rifampicin (RIF)-resistant Mycobacterium tuberculosis strains isolated in China. The rifampicin resistance determination regions (RRDR) of the rpoB genes of 242 M. tuberculosis strains were sequenced, including 193 RIF-resistant, 46 RIF-sensitive clinical isolates and three manually induced RIF-resistant tuberculosis strains. Mutations in the 81 bp RRDR of the rpoB gene were identified in 89.6% (173/193) of RIF-resistant clinical isolates. No mutation was observed in RIF-sensitive strains. Ser531Leu mutations accounted for 46.1% (89/193) of RIF-resistant strains; the mutation frequency of 526-His was 17.6% (34/193) in RIF-resistant strains. Furthermore, a combination of 2-3 single-point mutations was observed in 24 RIF-resistant strains (12.4%; 24/193). Mutations in three manually induced RIF-resistant tuberculosis strains were located at codons 531 and 526, respectively. The results indicate that about 90% of rifampicin-resistant M. tuberculosis strains isolated in China had rpoB mutations;531-Ser and 526-His were the most common positions substituted; high-level rifampicin-resistant strains had a higher frequency of 531-Ser mutations than low-level rifampicin-resistant strains. Sequencing analysis of the 81 bp fragment in the rpoB gene is useful in predicting the rifampicin-resistant phenotype.     

肝细胞癌高表达基因TPT1真核报告表达载体的构建及鉴定

目的构建TPT1真核报告表达载体pEGFP-N3TPT1,为进一步研究其功能奠定基础.方法通过PCR和酶切的方法获取具有黏性末端的TPT1基因的全长开放读码框,将其定向连入真核表达载体pEGFP-N3绿色荧光报告基因的氨基侧,构成pEGFP-N3TPT1的真核报告表达载体,通过酶切和测序鉴定TPT1的正确插入.结果酶切和测序均证实TPT1正确插入了真核报告表达载体pEGFP-N3TPT1中.结论成功构建了TPT1的真核报告表达载体pEGFP-N3TPT1.     

拉米夫定治疗慢性乙型肝炎中变异病毒株的动态变化

目的:建立定量检测及监测乙肝病毒DNA的rtM204I/V(YMDD)及rtL180M变异的方法.方法:以克隆、测序鉴定及构建乙肝病毒DNA YMDD及变异(YIDD和YVDD)质粒作为标准,4例接受拉米夫定治疗(100 mg/d,疗程48 wk以上)的慢性乙型肝炎患者血清标本为对象,用焦磷酸测序的方法检测变异位点核苷酸的频率,并计算变异株的含量比例,通过检测不同变异株类型的标准质粒,确定测序峰图的背景信号.结果:通过检测标准质粒后,确定背景信号为5%,变异位点调整后的核苷酸频率转化为变异病毒株的比例后,4例患者治疗前均检测出变异的病毒株(4.5%-33%),并且随治疗时间延长呈增多的趋势.病毒载量及ALT分析提示基因型耐药发生后,将发生病毒学反跳及临床耐药.结论:焦磷酸测序可以定量检测及动态监测变异病毒株的含量.拉米夫定耐药突变株在拉米夫定治疗前已存在,并随治疗时间的增加而增长,出现病毒学反弹及临床耐药.     

Heterotropic interactions in aspartate transcarbamoylase: turning allosteric ATP activation into inhibition as a consequence of a single tyrosine to phenylalanine mutation.

Aspartate transcarbamoylase (EC 2.1.3.2) is extensively studied as a model for cooperativity and allostery. This enzyme shows cooperativity between the catalytic sites, and its activity is feedback inhibited by CTP and activated by ATP. These regulatory processes involve several interfaces between catalytic and regulatory chains as well as between domains within these two types of chains. As far as the regulatory chain is concerned, its two domains are in contact through a hydrophobic interface, in which a tyrosine residue is inserted in a pocket involving two leucine residues of the allosteric domain and a valine and a leucine residue of the zinc domain. To probe the possible implication of this hydrophobic core in the CTP and ATP regulatory effect, the tyrosine was replaced by a phenylalanine through oligonucleotide-directed mutagenesis. Interestingly, the resulting mutant shows a complete inversion of the ATP effect; it is now inhibited by ATP instead of being activated by this nucleotide triphosphate. This mutant remains normally sensitive to the feedback inhibitor CTP. This result shows that the hydrophobic interface between the two domains of the regulatory chain plays an important role in the discrimination between the regulatory signals promoted by the two allosteric effectors.     

The use of computerized birthday greeting reminders in the management of diabetes

BACKGROUND: Although mailed reminders have been used for prevention among general populations, few studies have evaluated their effectiveness among chronically ill populations. OBJECTIVE: We evaluated the effectiveness of mailed reminders for improving diabetes management. The reminder included a letter from the individual's primary care physician (PCP), a self-care handbook, a preventive care checklist, and specific recommendations regarding receipt of routine monitoring and screening. METHODS: Of 195 PCPs practicing with a large group practice, 111 agreed to have their adult patients with diabetes randomized to receive the reminder (n = 1,641) or usual care (n = 1,668). Using data from automated databases, we fit generalized estimating equations to evaluate the effect of reminder receipt on fasting lipid profile and glycated hemoglobin testing, dilated retinal exam receipt, and visit frequency during the 6 and 12 months following randomization, and glycated hemoglobin and cholesterol levels in the year following randomization. RESULTS: Reminder and usual care recipients did not differ in sociodemographic, clinical, or prior testing characteristics. In the 6 months following randomization, reminder recipients were more likely to receive a retinal exam (odds ratio [OR], 1.29; 95% confidence interval [95% CI], 1.12 to 1.49) and diabetes visit (OR, 1.28; 95% CI, 1.12 to 1.47). In the 12 months following randomization, reminder recipients were more likely to receive a glycated hemoglobin test (OR, 1.21; 95% CI, 1.03 to 1.43), retinal exam (OR, 1.23; 95% CI, 1.07 to 1.41), and diabetes visit (OR, 1.25; 95% CI, 1.09 to 1.29). In the follow-up year, reminder recipients also tended to have a glycated hemoglobin test that did not reflect poor control (<9.5%). CONCLUSIONS: We found small but significant improvements in the management of patients with diabetes receiving a computerized mailed reminder.     

氯通道参与脑血管平滑肌细胞Ca2+池操纵性Ca2+内流

研究Cl-通道在牛脑血管平滑肌细胞Ca2+池操纵性Ca2+内流中的作用.采用培养的脑血管平滑肌细胞,在生物荧光双波长影像分析系统用Fura-2/Am荧光探针测定单个细胞内游离Ca2+浓度.结果发现① Cl-通道阻断剂DIDS(0.75 μmol/L)能降低内皮素1(10-7 mol/L)刺激引起的脑血管平滑肌细胞Ca2+内流,抑制率为29.6%±3.9%,随后加入Cl-通道阻断剂NPPB(10 μmol/L)能继续降低平台相,抑制率为44.9%±8.7%;交换加药顺序,NPPB能降低内皮素1刺激引起的Ca2+内流,DIDS能进一步降低Ca2+内流.②DIDS(0.75 μmol/L)能降低三磷酸腺苷(10 μmol/L)刺激引起的脑血管平滑肌细胞Ca2+内流,抑制率为26.7%±10.5%,随后加入NPPB(10 μmol/L)能继续降低平台相,抑制率为54.3%±9.6%;交换加药顺序,NPPB能降低三磷酸腺苷刺激引起的Ca2+内流,DIDS能进一步降低Ca2+内流.③DIDS(0.75 μmol/L)能降低环匹阿尼酸(10 μmol/L)刺激引起的脑血管平滑肌细胞Ca2+内流,抑制率为26.5%±5.0%,随后加入NPPB(10 μmol/L)能继续降低平台相,抑制率为46.1%±4.2%;交换加药顺序,NPPB能降低环匹阿尼酸刺激引起的Ca2+内流,DIDS能进一步降低Ca2+内流.提示对DIDS、NPPB敏感的非同一性Cl-通道参与内皮素1、三磷酸腺苷、环匹阿尼酸触发的脑血管平滑肌细胞 Ca2+池操纵性Ca2+内流.     

脑尔康对Alzheimer病小鼠脑细胞凋亡相关基因表达的影响

目的　观察复方中药脑尔康对 Alzheimer病 (AD)模型小鼠 ,学习记忆障碍的改善作用及对凋亡相关基因的调控作用。方法　用跳台法测试各组小鼠学习记忆功能 ,用 SP免疫组化法检测 Fas、Bcl- 2阳性细胞计数。结果　模型组与空白对照组比较 ,触电时间延长 ,潜伏期缩短 ,错误次数增多 ;Fas、Bcl- 2表达升高 (均 P<0 .0 1 )。各用药组与模型组比较触电时间缩短 ,潜伏期延长 (均 P<0 .0 5) ,Fas、Bcl- 2表达下调 (P<0 .0 5或 P<0 .0 1 )。各参数中药中、小剂量组优于西药组。结论　脑尔康能改善 AD小鼠学习记忆障碍具有促智作用 ,可通过调控凋亡相关基因表达 ,抗脑细胞凋亡 ,减少神经元丢失 ,而发挥抗痴呆作用     

Management of facial palsy after temporal bone fracture via the transmastoid approach

Conclusion: The outcomes of extended subtotal facial nerve decompression via the transmastoid approach were good for facial palsy after temporal bone fracture (TBF). Surgical decompression should be carried out as soon as possible within 8 weeks after trauma. Objective: To present outcomes of facial palsy after TBF via the transmastoid approach and to describe our experience of management of facial palsy in TBF. Methods: A consecutive clinical series was reviewed retrospectively. Eighteen cases that underwent extended subtotal facial nerve decompression (decompression from the stylomastoid foramen to the labyrinthine segment) due to facial palsy after TBF involving the perigeniculate ganglion region were analyzed. The patients were operated between 2 and 14 weeks after trauma. Results: In all, 83.3% of the 18 cases recovered to normal or near-normal level (House-Brackmann (HB) grade I or II). Among the 12 cases operated within 8 weeks after trauma, 11 cases (91.7%) recovered to normal or near-normal level. In contrast, four of the six patients (66.7%) who were operated between 9 and 14 weeks after trauma recovered to HB grade I or II.