Studies on the structure of bovine factor V by scanning transmission electron microscopy

We studied purified bovine factor V (mol wt 330,000) by scanning transmission electron microscopy (STEM) of freeze-dried unstained or negatively contrasted preparations. Freeze-dried molecules revealed discrete shapes ranging from roughly spheroidal (100 to 120 nm) to oblong (140 to 200 nm in length X 50 to 100 nm in width). Oblong shapes could often be resolved into two or three distinct domains, ranging from 60 to 100 nm in diameter. A "satellite" nodular structure (30 to 50 nm in diameter) connected to the main molecule by a thin stalk (approximately 10 nm wide) up to 80 nm in length was occasionally seen. Glutaraldehyde-treated preparations yielded the same shapes as were seen in unfixed preparations but revealed better definition of submolecular features and "satellite" nodules. STEM mass analysis confirmed that each of the different shapes represented a monomolecular form of factor V. Negatively stained images revealed objects having the same general shapes as freeze-dried molecules, although greater detail was evident. Some images suggested that molecules consist of five or more discrete parts. Taken together, these observations indicate that factor V molecules are multidomainal, flexible structures that tend to have an irregular oblong shape with an axial ratio between 3:2 and 2:1.     

The multifaceted roles of nitric oxide in cancer

The roles of nitric oxide (NO) in numerous disease states have generated considerable discussion over the past several years. NO has been labeled as the causative agent in different pathophysiological mechanisms, yet appears to protect against various chemical species such as those generated under oxidative stress. Similarly, NO appears to exert a dichotomy of effects within the multistage model of cancer. Chronic inflammation can lead to the production of chemical intermediates, among them NO, which in turn can mediate damage to DNA. Yet, NO also appears to be critical for the tumoricidal activity of the immune system. Furthermore, NO can also have a multitude of effects on other aspects of tumor biology, including angiogenesis and metastasis. This report will discuss how the chemistry of NO may impact the initiation and progression stages of cancer.      

Expanding the therapeutic repertoire of epidermal growth factor receptor blockade: radiosensitization

Expression of epidermal growth factor receptor (EGFR) has been associated with radioresistance in cancer. Moreover, tumour cell recovery after irradiation paradoxically occurs, in part, as a result of activation of EGFR signalling by such treatment. A recent article by Huang, Li, Armstrong and Harari provides strong rationale for considering the anti-EGFR agent ZD1839 ('Iressa') as a radiosensitizing strategy. With the use of several in vitro and xenograft models of human squamous cell head and neck carcinoma, ZD1939 was shown to markedly improve radiotherapeutic response, with superior tumour inhibition and delayed tumour regrowth. Mechanisms underlying this effect included anti-proliferative and pro-apoptotic activity, with significant perturbation of tumour angiogenesis.     

腕关节极限运动与头-月-三角-钩骨融合体稳定性的关系

目的:较大运动强度对腕关节头-月-三角-钩骨四角融合体稳定性究竟有何影响,国内外尚无报道。分析腕关节极限运动与四角融合体稳定性的关系。方法:实验于2005-03/2006-03在南通大学骨科生物力学实验室完成。选用12具未经防腐处理的新鲜尸体肘关节以远标本,切断桡舟月韧带、舟月骨间韧带掌侧部分、舟月骨间韧带背侧部分、桡舟头韧带,建立腕关节不稳定模型后,进行头-月-三角-钩骨四角融合术。融合腕模拟屈、伸、尺偏及桡偏运动,腕关节在安全活动范围内从0°开始,每5°1个等级,每个方向分别施以5万次极限运动。每次运动前后均摄标准前后位及侧位片,测量前后位片融合体高度、融合体宽度、头月正位角及侧位片桡月角、头月角并观察克氏针松动及弯曲情况。所有腕关节均采用运动前后自身对照。结果:①当腕关节屈曲至35°、背伸至25°、桡偏10°、尺偏15°时,极限运动对融合体的稳定性无影响,未出现融合体的解体。②当腕关节屈曲至40°、背伸至30°时,头月角、桡月角及融合体高度与0°相比差异具有显著性意义(P<0.05);当桡偏至15°、尺偏至20°时,融合体的稳定性受到影响,头月正位角、融合体宽度与0°相比差异具有显著性意义(P<0.01)。③克氏针弯曲的临界值:平均在屈曲至43.3°、背伸至32.5°、尺偏至23.3°、桡偏至15.8°时克氏针弯曲。结论:极限运动时,在掌屈40°、背伸30°、桡偏15°、尺偏20°的范围内进行功能锻炼,不会影响四角融合体的稳定性,但应避免环转运动。     

Isolation of egg yolk IgY from hens immunized with S.m …

目的：从鸡蛋中提取特异性抗体,鉴定抗体性质并分析其蛋白质含量,以探索一种制备被动免疫防龋抗体的制备方法。方法变形链球菌ＧＴＦ高表达株Ｓ．ｍｕｔａｎｓＢ２９－３３及茸毛链球菌Ｓ．ｓｏｂｒｉｎｕｓ６７１５免疫母鸡,采用硫酸铵沉淀法提取鸡蛋黄抗体,ＳＤＳ－ＰＡＧＥ凝胶扫描鉴定抗体性质,分析其纯度并用分光光度法测蛋白质含量。结果：用硫酸铵沉淀法可提取出鸡蛋黄抗体,其性质为ＩｇＧ,蛋白质含量约为７．００ｍｇ     

脉冲电流对胰岛素经皮渗透的促进作用

实验结果表明,脉冲电流能有效地提高胰岛素的透皮扩散速率,并随着释放池中胰岛素浓度的递增,透皮扩散速率呈线性增加。同时,胰岛素在pH值偏离等电点的酸性溶液(pH3.6)中透皮速率最高,为324.2±33.4μU/(cm²·h),而在pH值高于等电点的溶液(pH7.4)中其透皮速率降至143.7±27.3μU/(cm²·h),在pH值接近等电点(pH5.3)时,胰岛素的透皮速率最低,为78.4±21.9μU/(cm²·h)。     

Evaluation of the chronic toxicity and oncogenicity of N,N-diethyl-m- toluamide (DEET)

Chronic toxicity and/or oncogenicity studies were conducted in rats, mice, and dogs with the insect repellent DEET. DEET was mixed in the diet and administered to CD rats for two years at concentrations that corresponded to dosage levels of 10, 30 or 100 mg/kg/day for males and 30, 100, or 400 mg/kg/day for females; to CD-1 mice for 18 months at dosage levels of 250, 500, or 1000 mg/kg/day; and to dogs for one year, via gelatin capsules, at dosage levels of 30, 100, or 400 mg/kg/day. In the rodent studies, each group consisted of 60 animals of each sex, and two concurrent independent control groups, each containing 60 animals/sex were included in each study. Each group in the dog study consisted of four male and four female dogs and one control group was included in the study. Treatment-related effects were observed at the highest dose level in all three studies. For rats, the effects included decreases in body weight and food consumption and an increase in serum cholesterol in females only. In mice, the effects observed were decreases in body weight and food consumption in both sexes. The effects observed in dogs included increased incidences of emesis and ptyalism, and levels of transient reduction in hemoglobin and hematocrit, increased alkaline phosphatase (males only), decreased cholesterol, and increased potassium. One male dog in the high-dose group also exhibited ataxia, tremors, abnormal head movements, and/or convulsions on several occasions during the study. The highest no- observed-effect levels (NO-ELs) for rats, mice and dogs were determined to be 100, 500, and 100 mg/kg/day, respectively. No specific target organ toxicity or oncogenicity was observed in any of the studies.      

Fatal bronchospasm after oral ingestion of isphagula

We report the case of a 40-year-old asthmatic who suffered fatal bronchospasm following oral injestion of a laxative containing isphagula.