颠茄类生物碱的毛细管气相色谱和色—质联用分析

本文用毛细管气相色谱和气相色谱-质量选择检测器分析颠茄生物碱类(莨菪碱、东莨菪碱、山莨菪碱和樟柳碱)的研究。对颠茄生物碱与不同硅烷化试剂、反应能力、反应时间以及反应温度作了探索。结果表明,MSTFA是最好的硅烷化试剂。文内给出了这些生物碱的原型和硅烷化衍生物的保留值和它们的特征性碎片离子。这些数据有助于该类生物碱的鉴定。方法已初步应用于这些生物碱在生物合成中的转化研究。此外,还讨论了颠茄生物碱类TMS衍生化的优点。     

Thrombolytic therapy with tissue plasminogen activator or streptokinase induces transient thrombin activity

We have determined the plasma level of fibrinopeptide A as a specific index of thrombin activity during the infusion of a thrombolytic agent in patients with acute myocardial infarction. Peripheral venous plasma levels of fibrinopeptide A increased following the initiation of thrombolytic therapy from 2.7 nmol/L to a peak of 13.0 nmol/L at 30 minutes with streptokinase and from 1.1 nmol/L to a peak of 10.7 nmol/L at 90 minutes with tissue plasminogen activator. The amount of fibrinogen converted to fibrin I was determined by integration of the plasma level of fibrinopeptide A over time. The amount of fibrin I formed over the five-hour period from the start of drug infusion was approximately 10 mg/dL in response to either streptokinase or recombinant tissue plasminogen activator. We conclude that activation of coagulation occurs in response to thrombolytic therapy despite heparin administration. This thrombin action, though transient, would be sufficient to cause rethrombosis if localized and incompletely opposed by fibrinolytic activity.     

The management of refractory gastric ulcer using H2-receptor antagonists.

BACKGROUND: There is little information on the natural history of refractory gastric ulcer, defined as non-healing on cimetidine > or = 1 g daily given for at least 3 months. SETTING: A district general hospital serving an industrial population. METHODS: Patients with refractory gastric ulcer had their treatment extended and/or the dose increased, and upon healing the majority were put on maintenance treatment with cimetidine 400 mg nightly or 1 g daily and their progress was followed. RESULTS: Of 536 patients with gastric ulcer, 74 (14%) were refractory. Fifty of the 74 (68%) refractory gastric ulcer patients were refractory on their very first course of cimetidine. They had no distinguishing demographic features. Healing occurred in 62 patients (84%) after a mean treatment period of 11.1 months; 28 patients required cimetidine > or = 2 g daily. Eleven of 23 (48%) patients relapsed on maintenance with cimetidine 400 mg compared with seven of 24 (29%) on 1 g daily. A total of 22 out of 62 (35%) relapsed; nine had a second refractory recurrence but none thereafter. Eleven patients were operated upon, seven for failed medical treatment. Only two patients eventually proved to have malignant disease. CONCLUSIONS: Refractory gastric ulcer is uncommon, transient and rarely malignant. Most patients can be satisfactorily managed medically.     

Reduced Ia-afferent-mediated Hoffman reflex in streptozotocin-induced diabetic rats

Familial amyloidotic polyneuropathy (FAP) is a late-onset inherited disease characterized by the deposition of amyloid fibrils. FAP is associated with mutations on the transthyretin (TTR) gene. A monoclonal antibody, MAb 39-44, reacting with high molecular weight aggregates of TTR but not with tetrameric TTR has recently been generated and characterized. This antibody recognizes a cryptic epitope that is expressed in isolated recombinant amyloidogenic mutants and in ex vivo amyloid. In the present work we show that this amyloid-specific antibody specifically recognizes in a direct enzyme-linked immunoassay (ELISA) plasma TTR from carriers of various mutations associated with FAP, both in asymptomatic individuals and in patients. In contrast, it does not react with plasma TTR from healthy individuals or that from carriers of nonpathogenic mutations. Using the ELISA developed in this study we identified three different TTR mutations in Portuguese patients with neuropathy of unknown cause, later shown to have amyloid tissue deposition. This antibody recognizes conformations that express cryptic epitopes shared by amyloidogenic TTR variants associated with FAP, not present among nonpathogenic TTR molecules. This antibody will contribute to further identify and characterize intermediates of the amyloidogenic cascade. In addition, it will also be useful for screening amyloidogenic TTR mutations in patients with neuropathy of unknown cause, prior to precise molecular diagnosis using protein and/or DNA analysis.     

Tracheobronchial stenosis in infants: successful balloon dilation therapy

Four infants with congenital or acquired tracheobronchial stenosis were successfully treated with angioplasty balloon catheter dilation. The technical details and complications of these procedures are described. The authors believe balloon dilation therapy should be considered as the initial form of therapy for tracheal stenosis in infants, even in the presence of complex stenotic lesions.     

P47 Creation of longer-lasting (substantive) oral care flavours

Mainstream oral care flavours are primarily designed to provide hedonic (taste) benefits and to promote breath freshness. In particular, a key criterion for a commercially successful toothpaste flavour is a long lasting reduction in the perception of mouth odour. Various additives can help deliver this benefit, in addition to flavours formulated according to patented guidelines. The residence time (substantivity) in the mouth of flavours and additives is clearly critical with respect to the longevity of the breath-freshening benefit, and little data are available in the literature to guide the selection of substantive components. The aim of this project was to investigate the dynamics of flavour loss from the buccal cavity following brushing using a mass spectrometer equipped with an atmospheric pressure headspace sampler which enabled real-time determination of flavour components in mouth air. A number of flavour ingredients found in peppermint- and spearmint-based oral care flavours were studied. The in vivo decay kinetics of flavour ingredient loss were quantified and found to be strongly related to the physicochemical properties of ingredients, except in the case of esters where a more complex dependence was observed arising from chemical transformation occurring in addition to physical transportation away from the mouth. Surprisingly, some materials were discovered to undergo rapid degradation with a half-life of minutes. Confirmatory studies of the decay kinetics of such materials were carried out in vitro, and structural features were identified which were associated with the observed hydrolytic vulnerability. This work has allowed the development of new guidelines to enable the creation of longer-lasting oral care flavours.     

Localization of neuroendocrine tumours with [111In] DTPA-octreotide scintigraphy (Octreoscan): a comparative study with CT and MR imaging

A wide variety of neuroendocrine tumours express somatostatin receptors, and can be visualized by radiolabelled somatostatin analogue scintigraphy. To investigate the value of [111In]-octreotide scintigraphy (Octreoscan), 48 patients (37 with proven carcinoid, pancreatic endocrine and medullary carcinoma of thyroid tumours, 11 with neuroendocrine syndromes multiple endocrine neoplasia (MEN-I) and Zollinger-Ellison syndrome (ZES) were examined with 111In-DTPA-D-Phe1- octreotide. Scintigrams were obtained at 24 and 48 h, and the results were compared with CT and magnetic resonance imaging (MRI). Thirty-five of 48 patients had positive [111In]-octreotide scintigraphy (23/25 (92%) carcinoids, 8/9 (89%) PETs, 4/11 (36%) MEN-I & ZES). Of the 42 lesions located by conventional imaging techniques, 37 (88%) were also identified by Octreoscan. Unexpected lesions (40 sites), not detected by CT or MR imaging were found in 24/48 (50%) patients. [111In]- octreotide scintigraphy has a higher sensitivity for tumour detection, and is superior to MR imaging and CT scanning in the identification of previously unsuspected extraliver and lymph node metastases. It may also be helpful for the localization of clinically suspected tumours in patients with MEN-I and ZES.      

体外培养脂肪组织来源干细胞与胶原/壳聚糖复合支架的亲和性

目的：制备适合脂肪组织来源的干细胞生长的支架,观察复合支架各组成的体积比率与细胞培养的亲和性. 方法：实验于2006-09/2007-01在大连理工大学干细胞与组织工程研发中心完成.①实验方法：将3.55 g/L Ⅰ型胶原和20 g/L壳聚糖分别以9∶1,7∶3,5∶5,3∶7,1∶9的体积比混合冻干,碳化二亚胺/N-羟基琥珀酰亚胺交联后再次冻干并进行分析.②实验评估：扫描电镜观察不同材料交联前后的微观结构;IPP软件分析计算支架的平均孔径;测量支架的吸水性和孔隙率;通过胶原酶检测支架的体外生物可降解性;扫描电镜和苏木精-伊红染色观察脂肪组织来源的干细胞在复合支架上的生长情况. 结果：①交联前后的微观结构：冻干后的各种支架材料呈白色,表面粗糙,材料内部呈海绵状多孔隙结构,其中以胶原/壳聚糖体积比为9∶1的复合支架最为疏松,1∶9的支架最致密.扫描电镜下支架的胶原含量越高,支架内的胶原丝越多,支架的孔与孔之间相互连通构成了通孔.交联前后支架的形态结构无明显改变.②支架的平均孔径∶交联后体积比为9∶1,7∶3和5∶5的复合支架孔径50～200 μm,可用于细胞的三维培养.③支架的吸水性和孔隙率∶体积比为5∶5的复合支架的吸水性和含水量最高,而7∶3次之;多孔支架在水中未发生明显的溶胀现象;支架的孔隙率均在90%以上.④支架的体外生物可降解性：未交联的支架随着胶原含量的减少,支架的降解速率增加.而交联后随着胶原含量的减少,降解速率减慢,交联后的复合支架降解速度较未交联慢.⑤脂肪组织来源的干细胞在复合支架上的生长情况：脂肪组织来源的干细胞在支架上培养5 d后扫描电镜观察细胞在7∶3的支架上爬行生长并融合成片,苏木精-伊红染色观察支架孔内及表面出现大量的细胞团,并融合成片状,而5∶5支架上黏附生长的细胞较少. 结论：结合支架的孔径、吸水性、孔隙率、体外生物可降解性和细胞与支架的生物相容性,可知体积比为7∶3的复合支架对脂肪组织来源的干细胞的亲和性较好,适于脂肪组织来源的干细胞的三维培养.