Oxidative damage on DNA induced by asbestos and man-made fibers in vitro

Summary We compared the potential of asbestos and man-made fibers to attack DNA by the determination of the yield of 8-hydroxy-2-deoxyguanosine (8-OH-dGuo) under several in vitro conditions. Asbestos induced 6.6–99.8 of 8-OH-dGuo per 10⁵ dGuo in calf thymus DNA after 20 h of incubation, while the levels of 8-OH-dGuo in man-made fibers were low (3.6–9.4). The amounts of 8-OH-dGuo were strongly stimulated by the addition of H₂O₂ in asbestos, but not in man-made fibers. However, the yield of 8-OH-dGuo was induced more than that with asbestos by the further addition of FeSO₄ in attapulgite, fiberglass, potassium titanate whisker, and metaphosphate polymer. The addition of ethylene diamine tetraacetic acid (EDTA) promoted the induction of 8-OH-dGuo with asbestos and H₂O₂. The effects of mannitol (known as a hydroxy radical scavenger) were not dramatic on 8-OH-dGuo induction by all fibers except fiberglass and basic magnesium sulfate whisker, which induced higher amounts after mannitol addition than in these fibers and H₂O₂. Therefore, it was suggested that asbestos could damage DNA, resulting in 8-OH-dGuo as a cause of point mutation, and also several types of manmade fibers had similar effects to asbestos under certain conditions.     

Effects of intravenously administered lidocaine on pulmonary vagal afferents and phrenic nerve activity in cats

The ability of lidocaine to suppress activity of single vagal afferent fiber and that of phrenic nerve was studied in 20 cats anesthetized with pentobarbital. Slowly adapting stretch receptors (SAR, n = 16) and rapidly adapting stretch receptors (RAR, n = 7) were identified by their discharge pattern to pulmonary inflation. Intravenous lidocaine (1mg·kg^–1 or 2mg·kg^–1) produced a suppression of SAR activity but not of RAR activity. Suppression of phrenic nerve activity lasted much longer than that of SAR. These findings indicate that iv lidocaine acts more dominantly on CNS than on peripherals. We conclude that iv lidocaine prevents cough and hemodynamic changes caused by airway manipulation mainly through its action on CNS and not on peripherals (peripheral nerves or their receptor).(Aoki M, Harada Y, Namiki A, et al.: Effects of intravenously administered lidocaine of pulmonary vagal afferents and phrenic nerve activity in cats. J Anesth 6: 395–400, 1992)     

降纤酶低分子肝素治疗短暂性脑缺血发作的研究

目的 观察降纤酶与低分子肝素治疗短暂性脑缺血发作的效果及副作用。方法 选择本院神经内科住院患者36例应用降纤酶10U加入加入250ml生理盐水中静脉滴注，隔日1次，共3次；低分子肝素0．5ml脐旁皮下注射，12h 1次，连用7—10d,同时常规给予复方丹参滴注，口服尼莫地平，维生素E，维生素C，停用低分了肝素后给予肠溶阿斯匹林75mg，每日1次口服。结果 治疗开始后TLA发作相继减少，停止发作时间分别为1d内9例，3d内15例，5d内12例。随访6个月—1年，1例2个月后复发，重新应用上药治愈。结论 降纤酶与低分子肝素治疗TLA安全有效、无明显副作用、不易复发。     

多通道光纤化学传感器连续在位监测固体制剂的体外溶出度多通道光纤化学传感器连续在位监测固体制剂的体外溶出度

目的 为连续在位监测固体制剂的体外溶出度,自制多通道光纤化学传感溶出仪。方法 用自制光纤荧光溶出度监测仪与ZRS-4型智能溶出仪联用,连续在位监测氧氟沙星片、甲硝唑片、呋喃妥因肠溶片的体外溶出度,溶出曲线经微机从5种常用数学模型中根据相关系数R值,优选最佳模型进行拟合。结果 方法的回收率分别为97.4%～104.4%, 97.4%～103.8%, 96.6%～102.1%,日内、日间的RSD均小于5%。经与中国药典2000版方法及美国药典23版方法对照,各时间点药物累积溶出量和拟合后提取的参数均无显著性差异(P>0.05)。结论 本法简便、快速,结果准确、可靠,重现性好。     

In vitro evaluation study of the membrane autotransfusion system experimental prototype: MATS-I

Abstract: Membrane Autotransfusion System (MATS) utilizing plasmapheresis technology has been developed in our laboratory. A specially designed polyethylene hollow fiber membrane was utilized. This study was conducted to evaluate performance of the first experimental prototype, MATS-I. The results of this study showed that the MATS-I could concentrate diluted blood at 10% of the initial hematocrit concentration (HCTi) into over 40% after passing through the system at a transmembrane pressure of 70 mm Hg. Moreover, the MATS-I can continuously treat 10,000 ml of diluted blood at various HCTi levels without deteriorating its performances. Even though the MATS-I met all required performances as an autotransfusion system, several areas of improvement of the system were necessary to meet various clinical needs. The next prototype, MATS-II, can be designed based on experiences obtained from the MATS-I. The MATS is smaller, more atraumatic and continuous, and is a faster system when compared to the currently available centrifugal autotransfusion devices.     

离子交换纤维对阿魏酸的吸附和解吸研究

 目的　测定自制的强碱性离子交换纤维对阿魏酸的吸附和解吸的性能。方法　采用测定静态吸附速率曲线及测定30.8K的吸附等温线的方法,并对不同入口浓度和不同流速下,阿魏酸在固定床吸附柱上的动态吸附过程进行了研究。结果　离子交换纤维对阿魏酸的静态饱和吸附量为180.4mg·g^-1(干纤维),用少量甲醇和稀盐酸即可将吸附在纤维上的阿魏酸完全解吸。结论　离子交换纤维对阿魏酸的吸附速率远大于D2.96离子交换树脂对阿魏酸的吸附速率,是提纯和分离阿魏酸的一种新型离子交换剂。     

玻璃纤维粉尘对呼吸系统影响的调查

目的探讨玻璃纤维粉尘对呼吸系统的影响。方法选择玻璃纤维粉尘作业130名男性工人为研究对象,并以某化妆品厂130名男性工人作为对照组,进行鼻、咽喉、高千伏胸部X射线影像学检查和肺功能测定。结果玻璃纤维作业工人慢性鼻炎检出率20.77%,慢性咽炎62.31%,肺纹理改变19.23%,肺功能“小气道功能轻度异常”16.5%,显著高于对照组(P<0.05),且随工龄增长,检出率升高。结论玻璃纤维粉尘对呼吸系统有一定危害作用。     

Increased granule cell neurogenesis in the adult dentate gyrus following mossy fiber stimulation sufficient to induce long-term potentiation

Neurons are continually added at a low rate to the granule cell layer of the dentate gyrus during adulthood in rats. The functional significance of this unusual feature is not completely understood, although recent studies suggest continued granule cell neurogenesis is essential for normal learning and memory. We report here that, in the adult rat, stimulation of the granule cell mossy fibers sufficient to induce long-term potentiation (LTP) increases the number of newly formed granule cells in the dentate gyrus, indicating that granule cell neurogenesis is regulated by efferent activity and, possibly, the induction of LTP.