Imaging of thoracic aortic dissection

Acute thoracic aortic dissection has a high mortality if untreated, so the diagnosis must be rapidly made if mortality is to be lowered significantly. Multiple imaging techniques are often used. This retrospective study from 1988 to 1993 assesses the usefulness in diagnosis of chest X-rays, computed tomography (CT) scanning, aortography, magnetic resonance imaging (MRI), trans-thoracic (TTE) and trans-oesophageal (TOE) echocardiography. Forty-two patients with a final clinical diagnosis of dissection were studied. The diagnosis was confirmed in 16 (13 at surgery and three at autopsy). Three died with dissection given as the only cause for death. Chest X-ray abnormalities were seen in all 19 patients with surgery or death from dissection, with a widened mediastinum and/or dilated aorta being present in 17. In the group of 16 patients with surgery or autopsy proof, CT scans found dissections in 9 of 12 patients studied and correctly classified the type in only five. Aortography was performed in five, with accurate depiction of dissection and type in all. TTE found dissections in three of eight patients imaged by this method. MRI and TOE were performed each on two patients, with accurate depiction of dissection and type in each. Because of the relatively low sensitivity of CT scanning in defining aortic dissections Westmead Hospital is currently assessing the use of TOE as the prime imaging modality prior to surgical intervention.     

带股骨大粗隆稳定钢板的动力髋螺钉在不稳定型股骨粗隆间骨折

不稳定型股骨粗隆部骨折采用动力髋螺钉（DHS）固定效果欠佳，术后可出现骨折再移位、内固定松动、并发髋内翻畸形等.自2003年7月-2005年12月，采用DHS加TSP（股骨大粗隆稳定钢板），对32例不稳定型股骨粗隆部骨折进行了手术治疗，临床效果满意，现报告如下。     

Molecular mechanisms accounting for fibrinogen deficiency: from large deletions to intracellular retention of misfolded proteins

Summary.  Fibrinogen, the soluble precursor of fibrin, which is the main protein constituent of the blood clot, is synthesized in hepatocytes in the form of a hexamer composed of two sets of three polypeptides (Aα, Bβ, and γ). Each polypeptide is encoded by a distinct gene, FGA, FGB and FGG , all three clustered in a region of 50 kb on 4q32. Congenital afibrinogenemia is characterized by the complete absence of fibrinogen. The first causative mutation for this disease was identified in Geneva in a non-consanguineous Swiss family in 1999: the four patients were homozygous for a large deletion in the fibrinogen cluster, which eliminated almost the entire FGA genomic sequence. Mutations in the fibrinogen genes may lead to deficiency of fibrinogen by several mechanisms: acting at the DNA level, at the RNA level by affecting mRNA splicing or stability, or at the protein level by affecting protein synthesis, assembly or secretion. Recent reviews have provided helpful updates for the rapidly growing number of causative mutations identified in patients with fibrinogen deficiencies, either afibrinogenemia or hypofibrinogenemia. The aim of this review is to highlight specifically the subset of mutations that allow fibrinogen chain synthesis and hexamer assembly but impair secretion. Indeed, functional studies of these mutations have shed light on the specific sequences and structures in the fibrinogen molecule involved in the quality control of fibrinogen secretion.     

AG825对乳腺癌细胞的辐射增敏作用

目的：通过体外实验观察酪氨酸蛋白激酶抑制剂AG825对人类表皮生长因子受体2（ERBB-2）高表达乳腺癌细胞的生长抑制作用和辐射增敏作用，并从DNA双链断裂（Double strand break，DSB）损伤修复的角度初步探讨AG825辐射增敏机制。方法：首先通过MTT比色法观察了不同浓度AG825对ERBB-2高表达乳腺癌细胞系MDA—MB-453生长抑制作用。然后将细胞设为空白对照组，单纯放射组，AG825预处理组。通过克隆形成实验观察AG825预处理组和单纯辐射组乳腺癌细胞辐射后生存分数（Survivial fraction，SF）的差异。并且通过单细胞中性凝胶电泳分析了AG825预处理对辐射诱导的DSB的影响。同时用免疫印记法分析AG825预处理后MDA—MB-453细胞在辐射后不同时间DSB修复的关键激酶DNA依赖蛋白激酶催化亚单位（DNA dependent protein kinase catalytic subunit，DNA—PKcs）蛋白的表达情况。结果：MTT比色法显示AG825对MDA—MB-453生长抑制作用随AG825浓度增高而增加。辐射后单纯放射组MDA—MB-453细胞生存分数较空白对照组明显下降。AG825预处理组辐射后生存分数较单纯放射组进一步下降，同时DSB较单纯放射组增加。免疫印记显示单纯放射组DNA—PKcs蛋白表迭在辐射后较空白对照组增加，而AG825预处理组DNA—PKcs表达较单纯放射组下降。结论：AG825对ERBB2高表达乳腺癌细胞具有生长抑制作用一、并且其对ERBB2高表达乳腺癌细胞具有辐射增敏作用，其辐射增敏机制可能与AG825抑制DNA—PKes蛋白表达而减少辐射后DSB修复有关。但还需进一步的体内实验来评价AG825辐射增敏作用。     

Effect of gamma-linolenic acid on microsomal oxidation in the rat liver following gamma-irradiation

The antioxidant and radioprotector properties of gamma-linolenic acid isolated from the seeds of Borago officialis were studied on rats gamma-irradiated to a dose of 1 Gy. The irradiation caused an increase in the content of malonaldehyde in microsomal liver fraction and disturbed the metabolism of xenobiotics. The administration of gamma-linolenic acid in the form of a commercial drug Neoglandin (daily dose, 150 mg/kg, p.o.; over 1, 3, or 7 days after irradiation reduced the level of lipid peroxidation (for all treatment schedules), normalized the activity of NADPH-oxidase, NADH-oxidase, and NADPH-reductase, and increased the content of cytochromes P-450 and b5 as compared to bothirradiated and control animals.     

Investigation of the chemical structure and biological activity of oligosaccharides isolated from rough-type Xanthomonas campestris pv. campestris B100 lipopolysaccharide

The rough-type lipopolysaccharide (LPS) of the phytopathogenic bacterium Xanthomonas campestris pv. campestris B 100 was isolated utilizing the hot phenol-water method and successively de-acylated by treatment with hydrazine and hot potassium hydroxide. Four compounds were separated by preparative high-performance anion-exchange chromatography and studied by sugar analysis and by 1D and 2D homonuclear and heteronuclear (1)H-, (13)C- and (31)P-NMR spectroscopy as well as ESI FT-MS. The two main products were a heptasaccharide and a pentasaccharide of the structures alpha-D-Manp-(1-->3)-alpha-D-Man p-(1-->4)-beta-D-Glcp-(1-->4)-alpha-D-Manp-3P -(1-->5)-alpha-Kdo-(2-->6)-beta-D-GlcpN-4P-(1-->6)-alpha-D-Glc pN-1P (1) and beta-D-Glcp-(1-->4)-alpha-D-Man p-3P-(1-->5)-alpha-Kdo-(2-->6)-beta-D-GlcpN-4 P-(1-->6)-alpha-D-GlcpN-1P (2), respectively. The products in smaller amounts were a heptasaccharide and pentasaccharide possessing the above structures plus a phosphate group at C-4 of the Kdo residue (compounds 3 and 4). Both, heptasaccharide 1 and pentasaccharide 2 were able to induce an oxidative burst in cell cultures of the non-host plant tobacco.     

尼可地尔治疗微血管性心绞痛的疗效及其对血管内皮功能的影响

目的探讨尼可地尔治疗微血管性心绞痛的临床疗效及其对血管内皮功能的影响。方法选择100例微血管性心绞痛患者,随机分为研究组和对照组各50例。对照组给予常规抗心绞痛治疗,研究组在对照组用药基础上给予尼可地尔片连续治疗3个月。治疗前后测定血浆内皮索（ET-1）、一氧化氮（NO）及血清高敏C反应蛋白（hs-CRP）水平。结果研究组症状疗效总有效率为94．0％,对照组为76．0％,差异有统计学意义（P〈0．05）。研究组心电图疗效总有效率为90．0％,对照组为72．0％,差异有统计学意义（P〈0．05）。研究组治疗后与治疗前比较NO水平显著升高,ET-1及CRP水平显著减低,差异均有统计学意义（P〈0．01）。结论尼可地尔通过抑制炎症因子、改善血管内皮功能机制改善微血管性心绞痛症状,且疗效显著。     

Tiacumicins, a novel complex of 18-membered macrolides. II. Isolation and structure determination

A novel complex of Gram-positive antibiotics has been isolated from the fermentation broth and mycelium of Dactylosporangium aurantiacum subsp. hamdenesis subsp. nov. The structures of these six compounds were deduced employing UV, MS, IR, and extensive 1D and 2D homonuclear and heteronuclear NMR experiments. Each component contained a highly unsaturated 18-membered macrolide ring. Components differed from one another by minor structural variations in the macrolide ring and by the number and esterification pattern of glycosidically bound sugars.     

Effect of acute alcoholic intoxication on lipogenesis in the liver of rats

Thirty minutes after a single ethanol injection (4 g/kg bw, i.p.) the activity of rat liver acetyl-CoA-synthetase and ATP-citralyase was decreased. Cholesterol synthesis estimated by label incorporation from 3H2O was increased whereas the synthesis of fatty acids remained at the control level. The possibility of alternative ways of acetyl-CoA production under the conditions of acute alcoholic intoxication is discussed.