含IKVAV肽自组装成凝胶的实验

目的:利用特定结构的多肽在生理条件下的自组装特性构筑功能性再生支架,对神经修复和再生具有重要意义,并可望突破其他支架材料的局限性。设计合成含IKVAV肽(C16H31O-AAAAGGGEIKVAV),并诱发其自组装过程。方法:实验于2005-01/2006-07在华中科技大学同济医学院附属协和医院骨科实验室完成。实验方法:①寡肽的合成:采用固相法合成肽。②寡肽自组装:取质量分数为0.01的寡肽溶液150μL,置于玻璃小瓶中,pH值调整为9.5,然后滴加等体积的磷酸盐缓冲液,震荡离心(2000r/min,离心10min)。实验评估:①高效液相色谱仪测肽纯度;色谱仪测肽的相对分子质量。②透射电镜下观察自组装凝胶超微结构。结果:①高效液相色谱仪示多肽纯度为95%,质谱仪示肽的相对分子质量为1351.6。②质量分数为0.01的肽溶液在磷酸盐缓冲液触发下数秒钟形成凝胶,透射电镜示自组装的凝胶为交织成网状的纤维结构,直径3～6nm,长度100～1500nm。结论:实验合成了含IKVAV肽,在磷酸盐缓冲液中可自组装成多孔凝胶结构。     

晚期脊髓损伤患者胚胎嗅鞘细胞移植后的电生理评价

目的:采用客观的电生理检查手段评价胚胎嗅鞘细胞移植治疗晚期脊髓损伤的有效性。方法:①对象:选择2003-02/2005-01北京市西山医院暨北京康复中心神经外科收治的接受人胚胎嗅鞘细胞移植治疗的晚期完全性脊髓损伤患者199例,男164例,女35例,平均年龄(34.7±11.3)岁,平均病程(4.7±5.5)年;受伤节段:颈段99例,胸段89例,胸腰段11例;受伤原因:车祸、摔伤、医源性损伤、机器挤压伤等。4个月流产胚胎由北京市虹天济神经科学研究院协作医院提供,产妇及其家属均签署知情同意书,实验经医院医学伦理委员会批准。②方法:取人胚胎嗅球,消化成单个嗅鞘细胞后培养2周。199例晚期完全性脊髓损伤患者均接受人胚胎嗅鞘细胞移植治疗,在全麻下行脊髓损伤节段后方入路,切开硬膜,显露出病变脊髓。分上下两点各注入50μL嗅鞘细胞悬液,细胞数共约1×106个。术后给予止血、抗感染等处理,未使用任何免疫抑制剂。③评估:移植前后分别采用肌电/诱发电位仪检查肌电图和椎旁躯体感觉诱发电位,每例患者检查2次,时间一致,且由同一医生操作。肌电图即检查患者大力收缩时的肌肉情况,以观察运动单位电位的数量、波幅及持续放电能力。椎旁躯体感觉诱发电位是于中线旁开2cm处两侧同时给予刺激,刺激强度以引起可见的肌肉抽动为准,在头皮上记录电位。方波刺激频率3Hz,强度20～40mA,时限0.2ms,观察感觉平面下降情况。结果:199例晚期完全性脊髓损伤患者均进入结果分析。①术后肌电图检查:93例(46.7%)显示部分受累肌肉大力收缩时募集波型改善,运动单位电位数量增加;105例(52.8%)无变化,1例(0.5%)比术前差。②椎旁躯体感觉诱发电位检查:90例(45.2%)显示感觉平面下降,其中左侧平均下降(1.9±1.2)个节段,右侧平均下降(2.0±1.2)个节段;107例(53.8%)无变化,2例(1.0%)双侧感觉平面上升。结论:对于胚胎嗅鞘细胞移植治疗晚期脊髓损伤患者,肌电图和椎旁躯体感觉诱发电位这两种电生理检查能较为客观的反映脊髓术后感觉和运动功能恢复情况。     

Aurolab aqueous drainage implant in the vitreous cavity: Our modifications over the conventional technique of glaucoma implant surgery

Glaucoma drainage devices (GDDs) are used for managing refractory glaucoma due to failed trabeculectomy, neovascular glaucoma, traumatic glaucoma, and secondary glaucoma post keratoplasty. Aurolab aqueous drainage implant (AADI) is a nonvalved drainage implant conventionally implanted with the tube placed in the anterior chamber. Studies about the outcome of the various aqueous drainage devices implanted in the anterior chamber have reported complications such as tube extrusion, migration, blockage, erosion, and corneal decompensation. We propose modifying the conventional GDD implantation technique by placing the tube in the vitreous cavity, thereby negating the risk of anterior segment complications in patients with refractory glaucoma whose anterior segment is already compromised. Another novel approach implemented in this technique was making a scleral tunnel instead of using a scleral or corneal patch graft to cover the tube to prevent its migration. This article describes the surgical steps of this technique and its advantages, along with a surgical video.     

Pharmacokinetics of oltipraz in diabetic rats with liver cirrhosis

Background and purpose:

The incidence of diabetes mellitus is increased in patients with liver cirrhosis. Oltipraz is currently in trials to treat patients with liver fibrosis and cirrhosis induced by chronic hepatitis types B and C and is primarily metabolized via hepatic cytochrome P450 isozymes CYP1A1/2, 2B1/2, 2C11, 2D1 and 3A1/2 in rats. We have studied the influence of diabetes mellitus on pharmacokinetics of oltipraz and on expression of hepatic, CYP1A, 2B1/2, 2C11, 2D and 3A in rats with experimental liver cirrhosis.

Experimental approach:

Oltipraz was given intravenously (10 mg·kg⁻¹) or orally (30 mg·kg⁻¹) to rats with liver cirrhosis induced by N-dimethylnitrosamine (LC rats) or with diabetes, induced by streptozotocin (DM rats) or to rats with both liver cirrhosis and diabetes (LCD rats) and to control rats, and pharmacokinetic variables measured. Protein expression of hepatic CYP1A, 2B1/2, 2C11, 2D and 3A was measured using Western blot analysis.

Key results:

After i.v. or p.o. administration of oltipraz to LC and DM rats, the AUC was significantly greater and smaller, respectively, than that in control rats. In LCD rats, the AUC was that of LC and DM rats (partially restored towards control rats). Compared with control rats, the protein expression of hepatic CYP1A increased, that of CYP2C11 and 3A decreased, but that of CYP2B1/2 and 2D was not altered in LCD rats.

Conclusions and implications:

In rats with diabetes and liver cirrhosis, the AUC of oltipraz was partially restored towards that of control rats.     

Cost‐effectiveness of CT thorax and bronchoscopy in haemoptysis with normal CXR for exclusion of lung cancer

As fibre‐optic bronchoscopy and CT thorax become more widely used, patients with haemoptysis who had normal CXR and sputum results are more commonly offered both CT and bronchoscopy to exclude lung cancer. Doctors who are under possible litigation pressure arising from missed diagnoses of lung cancer are often exhaustive in their investigations, even when the haemoptysis has been transient. The present study aims to investigate the number of cancer patients who can be detected with the two investigations, and compare recent similar study results with archive results. We found that despite the use of more efficient investigation tools, the yield is paradoxically much lower and, hence, less cost‐effective than that of previous studies. The likely reason is that doctors tend to over‐investigate, even for short‐term, minimal blood‐streaked sputum, which is common among simple bronchitis. In order to be more cost‐effective, these investigations should be used more selectively and for high risk patients such as those with prolonged haemoptysis and those who are heavy smokers.     

野菊花水提液抗氧化作用的实验研究

目的：观察野菊花水提液的体内外抗氧化的作用。方法：分别用ＴＢＡ法、ＤＴＮＢ法及紫外分光光度测定脂质过氧化（ＬＰＯ）产物ＭＤＡ的含量、全血谷胱甘肽过氧化物酶（ＧＳＨ－Ｐx）及过氧化氢酶（ＣＡＴ）活力。结果：野菊花水提液体外可抑制大鼠心、脑、肝、肾组织自动ＬＰＯ及由Ｈ２Ｏ２引发的红细胞脂质过氧及溶血;小鼠ｉｇ给药２ｇ／（ｋｇ．ｄ）７ｄ,可显著升高全血ＧＳＨ－Ｐx、ＣＡＴ活力（Ｐ〈０．０５）。结论：野菊     

大鼠单克隆抗体与博来霉素A6偶联物治疗人大肠癌实验研究

用Dextran T-40为中介体偶联大鼠抗人大肠癌单克隆抗体R19和博来霉素A6。体外实验显示R19与A6偶联物对人盲肠癌细胞Hce-8693抑制50%克隆生成浓度(IC₅₀)为0.019μmol/L;游离A6及无关单抗与A6偶联物M3-A6分别为1.05和1.00μmol/L;对人结肠HT-29细胞IC₅₀为0.078μmol/L,而游离A6为4.0μmol/L。同时加入R19单抗能阻断R19-A6偶联物的细胞毒性。体内实验显示:R19-A6偶联物对裸鼠移植的人盲肠癌生长的抑制率达90%,而同等剂量的游离A6,R19与A6混合物和M3-A6的抑制率分别为52,34和48%。结果表明单抗R19与A6偶联物对人大肠癌的抑制作用明显比游离A6强。     

人单克隆抗体与平阳霉素偶联物治疗乳腺癌实验研究

抗乳腺癌人单抗CMI用DextranT-40为中介体的方法与平阳霉素(PYM)偶联,体外实验显示CMI-PYM偶联物对人乳腺癌细胞的IC₅₀(抑制50%克隆生成浓度)为0.35μmol·L^-1;游离PYM为4.0μmol·L^-1。裸鼠体内实验证明,局部给予CMI-PYM偶联物(2.5mg·kg^-1)对移植的人乳腺癌抑制率达95%,等剂量平阳霉素为58%。结果表明人单抗CMI-平阳霉素偶联物对乳腺癌有显著疗效,偶联物对肿瘤的抑制作用比游离平阳霉素更强。     

Regulation of microRNA biosynthesis and expression in 2102Ep embryonal carcinoma stem cells is mirrored in ovarian serous adenocarcinoma patients

Background

Tumours with high proportions of differentiated cells are considered to be of a lower grade to those containing high proportions of undifferentiated cells. This property may be linked to the differentiation properties of stem cell-like populations within malignancies. We aim to identify molecular mechanism associated with the generation of tumours with differing grades from malignant stem cell populations with different differentiation potentials. In this study we assessed microRNA (miRNA) regulation in two populations of malignant Embryonal Carcinoma (EC) stem cell, which differentiate (NTera2) or remain undifferentiated (2102Ep) during tumourigenesis, and compared this to miRNA regulation in ovarian serous carcinoma (OSC) patient samples.

Methods

miRNA expression was assessed in NTera2 and 2102Ep cells in the undifferentiated and differentiated states and compared to that of OSC samples using miRNA qPCR.

Results

Our analysis reveals a substantial overlap between miRNA regulation in 2102Ep cells and OSC samples in terms of miRNA biosynthesis and expression of mature miRNAs, particularly those of the miR-17/92 family and clustering to chromosomes 14 and 19. In the undifferentiated state 2102Ep cells expressed mature miRNAs at up to 15,000 fold increased levels despite decreased expression of miRNA biosynthesis genes Drosha and Dicer. 2102Ep cells avoid differentiation, which we show is associated with consistent levels of expression of miRNA biosynthesis genes and mature miRNAs while expression of miRNAs clustering to chromosomes 14 and 19 is deemphasised. OSC patient samples displayed decreased expression of miRNA biosynthesis genes, decreased expression of mature miRNAs and prominent clustering to chromosome 14 but not 19. This indicates that miRNA biosynthesis and levels of miRNA expression, particularly from chromosome 14, are tightly regulated both in progenitor cells and in tumour samples.

Conclusion

miRNA biosynthesis and expression of mature miRNAs, particularly the miR-17/92 family and those clustering to chromosomes 14 and 19, are highly regulated in both progenitor cells and tumour samples. Strikingly, 2102Ep cells are not simply malfunctioning but respond to differentiation specifically, a mechanism that is highly relevant to OSC samples. Our identification and future manipulation of these miRNAs may facilitate generation of lower grade malignancies from these high-grade cells.