Excitability of spinal cord and gracile nucleus neurons in rats with chronically injured sciatic nerve examined by c-fos expression

Low-threshold sensory pathways have been suggested to have an important role in the formation and maintenance of sensory abnormalities which are observed after peripheral nerve injury. Fos-like immunoreactive (Fos-LI) neurons are expressed in spinal cord laminae III-IV and the gracile nucleus by electrically stimulating the injured nerves at Abeta strength after sciatic nerve transection in rats. This suggests that the excitability of these neurons is increased by nerve injury. In this study, we investigated which receptors are involved in the regulation of the increased excitability in spinal and gracile nucleus neurons. The sciatic nerve of Sprague-Dawley rats (150 g) was transected 7 days before the experiment day. The rats were administered morphine, muscimol, baclofen, MK-801, CNQX, N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or clonidine i.p., and then electrically stimulated at 0.1 mA to the proximal region to the nerve injury site under urethane anesthesia. Two hours after the stimulation, Fos-LI expression was increased in the spinal cord dorsal horn and the gracile nucleus in control rats. Baclofen inhibited the Fos-LI expression both in the spinal cord and the gracile nucleus. Morphine inhibited only the Fos-LI expression in the posterior cutaneous (PC) nerve territory of laminae I-II, but not in the sciatic nerve (SC) territory, laminae III-IV nor the gracile nucleus. MK-801 had an inhibitory but complicated effect in laminae I-II and the gracile nucleus. The other drugs were not effective on Fos-LI expression. It is suggested that the GABA(B) receptor has a pivotal role in the regulation of Fos-LI expression after electrical stimulation to the injured low-threshold sensory fibers, and other receptors have little effect on the Fos-LI expression.     

Biological monitoring of isocyanates and related amines

Summary Two men were exposed to toluene diisocyanate (TDI) atmospheres at three different air concentrations (ca. 25, 50 and 70g/m³) . The TDI atmospheres were generated by a gas-phase permeation method, and the exposures were performed in an 8-m³ stainless-steel test chamber. The effective exposure period was 4h. The isomeric composition of the air in the test chamber was 30% 2,4-TDI and 70% 2,6-TDI. The concentration of TDI in air of the test chamber was determined by an HPLC method using the 9-(N-methyl-amino-methyl)-anthracene reagent and by a continuous-monitoring filter-tape instrument. Following the hydrolysis of plasma and urine, the related amines, 2,4-toluenediamine (2,4-TDA) and 2,6-toluenediamine (2,6-TDA), were determined as pentafluoropropionic anhydride (PFPA) derivatives by capillary gas chromatography using selected ion monitoring (SIM) in the electron-impact mode. In plasma, 2,4- and 2,6-TDA showed a rapid-phase elimination half-time of ca. 2–5 h, and that for the slow phase was > 6 days. A connection was observed between concentrations of 2,4- and 2,6-TDI in air and the levels of 2,4- and 2,6-TDA in plasma. The cumulated amount of 2,4-TDA excreted in the urine over 24 h was ca. 15%–19% of the estimated inhaled dose of 2,4-TDI, and that of 2,6-TDA was ca. 17%–23% of the inhaled dose of 2,6-TDI. A connection was found between the cumulated (24-h) urinary excretion of 2,4- and 2,6-TDA and the air concentration of 2,4- and 2,6-TDI in the test chamber. A connection was also observed between the rate of urinary excretion of 2,4- and 2,6-TDA over the last 2h of exposure and the air concentration of 2,4- and 2,6-TDI in the test chamber. Biological monitoring of exposure to monomeric 2,4- and 2,6-TDI by the analysis of 2,4- and 2,6-TDA in biological media is feasible. A method based on 24-h urine sampling and determination levels of 2,4- and 2,6-TDA in hydrolysed urine is recommended. However, exposure to TDI is often associated with aerosols containing polymeric TDI, and we do not know whether analysis of TDA in urine can also be used as a marker of exposure to TDI prepolymers.     

载重卡车和拖拉机振动参数的测量及对人体健康影响的研究

本研究对8种载重卡车、拖拉机驾驶员座位的振动进行测量,均超过ISO 2631—1985规定的暴露极限(E·L)界限值。特别是上海50型拖拉机、解放牌4吨翻斗车更为明显。对490名驾驶员进行了一般查体、心电图检查、视觉运动反应时测定和脊柱骨关节X线摄像,并与162名科室办公人员相对照。腰背痛主诉、血压偏高、心电图节律异常、视觉运动反应时减慢、胸腰椎增生性改变等均有较高的检出率,并随工龄的延长而增加。全身振动及其联合因素对人体健康的影响有必要进一步研究;我国全身振动的卫生标准及防治措施急待研制。     

山茨菇挥发油化学成分气相色谱-质谱联用分析

目的：分析山茨菇挥发油的化学成分。方法：用气相色谱-质谱联用法（GC-MS）分析。结果：山茨菇挥发油的化学成分，共鉴定了40个组分，其中芒樟醇、异石竹烯、β-金合欢烯、橙花叔醇、细辛醚、肉桂酸酯类等为其挥发油主要成分。结论：该结果可供临床研究参考。     

醒脑酊质量控制方法的研究

目的 :建立醒脑酊的质量控制方法。方法 :采用薄层色谱法对醒脑酊中的薄荷脑、丁香、冰片进行定性鉴别 ;并采用气相色谱法对该药中的薄荷脑进行含量测定。气相色谱条件 :以萘为内标物 ,填充玻璃柱 (2.1mm× 3.2m ,Shimadzu 7 G ,) ,载气N₂ ,流速 50mL·min^-1 ,柱温 145℃ ;进样口及检测器温度 180℃ ,不分流方式进样 ,进样量3μL。 结果 :薄层色谱图斑点清晰 ,阴性对照无干扰 ;气相色谱法精密度、重现性良好 ,平均加样回收率为 98.4% ,RSD=0.9%。结论 :本方法快速简便 ,结果准确 ,可用于控制醒脑酊的质量。     

救急行军散的质量标准研究

目的 :建立救急行军散 (薄荷脑、冰片、黄芩、雄黄、朱砂、苏铁蕨贯众、陈皮等 )的质量标准。方法 :通过TLC、GC对散剂中的黄芩、陈皮、苏铁蕨贯众、薄荷脑、冰片进行鉴别研究 ;同时采用GC测定散剂中的薄荷脑、冰片含量。结果 :TLC色谱中均能明显地检出黄芩、陈皮、苏铁蕨贯众药材 ,GC色谱中均能明显地检出薄荷脑、冰片 ,GC法测得薄荷脑、冰片的含量分别为 75 .6 9～ 78.5 1mg·g-1和 6 1.2 6～ 6 4 .14mg·g-1,平均加样回收率为 :薄荷脑 99.35 % (RSD为 0 .98% ) ,冰片99 .2 4 % (RSD为 1.0 5 % )。结论 :所建立的方法简便可行 ,重现性好 ,可用于救急行军散的质量控制     

气相色谱法测定紫金胶囊中麝香酮含量

目的 :建立以气相色谱法测定紫金胶囊中麝香酮含量的方法。方法 :样品用乙醚提取 ,以OV 17为气相色谱柱 ,柱温为 2 0 0℃ ,氢火焰离子化检测器 (FID) ,载气为N2 ,流速 5 0mL·min-1。测定紫金胶囊中麝香酮的含量。结果 :麝香酮在 1.5～7.5 μg范围间呈良好线性关系 ,平均回收率为10 2 .0 % ,RSD =3.1%。结论 :本方法简便、准确、重现性好 ,可作为本制剂的质量控制方法     

GC法测定丁蔻理中丸中丁香酚的含量

目的：采用气相色谱法测定丁蔻理中丸中丁香酚的含量。方法：气相色谱法，聚乙二醇(PEG)—20M柱，柱长2m，内径4mm；柱温180℃，进样器220℃，FID检测器；柱头压力：150kPa，内标物：桂皮醛。结果：所测丁香酚与其它组分具有良好的分离效果，线性范围为8.92～71．36μg／ml，平均回收率为99．9％，RSD为1．28％(n=5)。结论：本方法简便、快速，结果准确，可用于丁蔻理中丸中丁香酚的含量测定。     

绿衣枳壳指纹图谱的研究

目的 　应用 GC对绿衣枳壳药材挥发油进行指纹图谱研究。方法　色谱条件 :HP-1石英毛细管柱 ( 3 0 m× 0 .3 2 mm,0 .2 5μm) ,柱温条件 :起始温度 110℃ ( 2 0 min) 4℃·min- 1 14 0℃ ( 7min) 7℃· min- 1 2 2 0℃ ( 10 min) ;分流进样 ,分流比 1∶ 60 ;进样口温度 2 80℃。结果 　指纹图谱对绿衣枳壳中各成分均有较好分离。 结论 　该方法简便 ,准确 ,重现性好 ,可作为绿衣枳壳具有专属性的指纹图谱     

硝呋太尔中有机溶剂残留量的GC测定

采用毛细管气相色谱法，以外标法测定硝呋太尔中有机溶剂甲醇、乙醇、二嚼烷、N，N-二甲基甲酰胺的含量。采用二乙烯基苯／苯乙烯多孔聚合物为固定液的毛细管石英色谱柱，程序升温的方法。各组分的线性关系良好(r均大于0．999)，平均回收率分别为99．2％、96．2％、90．7％和98．8％，检测限分别为2．9、3．0、2．2和1．8ng。