丙泊酚、硫喷妥钠联合麻醉诱导对血液动力学的影响

目的：观察小剂量丙泊酚和硫喷妥钠联合用于麻醉诱导对血流动力学的影响及临床应用价值。方法：择期全身麻醉气管插管手术患者84例，ASAⅠ-Ⅱ级，随机分成3组（n=28），硫喷妥钠组（A组）：诱导量5mg/kg；丙泊酚组（B组）；诱导量2.0mg/kg；联合诱导组（C组）硫喷妥钠1－2mg/kg加丙泊酚0.5-1.0mg/kg，观察诱导后2min,5min,10min血液动力学变化。结果：C组在丙泊酚诱导前先静脉预注硫喷妥钠1－2mg/kg，患者静脉注射部位疼痛发生率明显低于B组（P＜0．01），平均动脉压和心率均无明显变化（P＞0．05），而A和B组给药后2min与5min平均动脉压均低于麻醉前，心率均高于麻醉前（P＜0．05－P＜0．05）。结论：丙泊酚与硫喷妥钠联合麻醉诱导具有协同作用，减少单独用药不良反应发生率，血液动力学稳定，麻醉诱导更加平稳，安全，为临床全麻诱导提供一种可行的方法。     

AN-132 block of cardiac sodium channels: A gate-related receptor analysis

Summary Based on the gate-related receptor hypothesis, an analysis of kinetics of AN-132, a new antiarrhythmic agent, blockade of cardiac sodium channels and the gate-related receptor which is bound by the drug was performed by computer simulation. Model-predicted apparent rates of onset of AN-132 (30 μmol/L) blocking were 0.051, 0.038, and 0.034 AF⁻¹ at stimulation frequencies of 1.0, 2.0 and 3.0 Hz, respectively. The time constant of recovery from block by AN-132 at resting potential -90 mV was 39.5 s. These findings are in agreement with those experimental data documented. The analysis of gate-related receptor shows that AN-132 binds the inactivation gate-related receptor, and the binding and unbinding are modulated by the inactivation process.     

Topical application of fluorides on teeth

Abstract Prevention of caries in exposed root surfaces constitutes an important clinical problem. It is thus important that clinicians involved with periodontology have an insight into fluoride prophylaxis. The understanding of the cariostatic mechanism of fluoride has improved during recent years. The aim of the present review is to give a short account of the present concept. Calcium fluoride appears to be the only product which is formed on enamel, dentin or cementum during brief topical treatments with fluoride or use of toothpaste containing fluoride. This calcium fluoride is stable in the oral environment: this is contrary to what was believed until recently. The calcium fluoride constitutes a pH-dependant reservoir of fluoride which releases fluoride when pH drops. The practical consequences of this concept is discussed.     

Differential effects of the pyrethroid tetramethrin on tetrodotoxin-sensitive and tetrodotoxin-resistant single sodium channels

The differential effects of the pyrethroid tetramethrin on tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant (TTX-R) single sodium channel currents in rat dorsal root ganglion (DRG) neurons were investigated using the outside-out configuration of patch-clamp technique. Channel conductances were 10.7 and 6.3 pS for TTX-S and TTX-R sodium channels, respectively, at a room temperature of 24–26°C. The single-channel current of TTX-S sodium channels at the test potential of −30 mV was −1.27 ± 0.25 pA, and was not changed after exposure to 10 μM tetramethrin (−1.28 ± 0.23 pA). The open time histogram of TTX-S single-channel currents could be fitted by a single exponential function with a time constant of 1.27 ms. After exposure to 10 μM tetramethrin, the open time histogram could be fitted by the sum of two exponential functions with time constants of 1.36 ms (τ_fast) and 5.73 ms (τ_low). The percentage of contribution of each component to the population was 62% for the fast component representing the normal channels and 38% for the slow component representing the tetramethrin modified channels. The amplitudc of TTX-R single-channel currents was slightly changed from −0.72 ± 0.14 to −0.83 ± 0.07 pA by 10 μM tetramethrin. The open time histogram of TTX-R single-channel currents could be fitted by a single exponential function with a time constant of 1.92 ms. In the presence of 10 μM tetramethrin, the open time histogram could be fitted by the sum of two exponential functions with time constants of 2.07 ms (τ_fast) and 9.75 ms (τ_slow). The percentage of contribution of each component was 15% for the fast, unmodified component and 85% for the slow, modified component. Differential effects of tetramethrin on the open time distribution of single sodium channel currents explains the differential sensitivity of TTX-S and TTX-R sodium channels.     

抑制剂对酪氨酸酶影响的初步研究

采用酶动力学及聚丙烯酰胺凝胶电泳方法研究了ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ、ＤＤＣ对酪氨酸酶的抑制作用。ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ为非竞争性抑制作用，随着抑制剂浓度增加，酶活性逐渐减弱。当ＮａＨＳＯ３、ＮａＮ３、ＫＳＣＮ的浓度分别达到１．２ｍｍｏｌ／Ｌ１２。５ｍｍｏｌ／Ｌ１２．５ｍｍｏｌ／Ｌ时，酶活性的抑制率为１００％、５０％、２４％。ＤＤＣ对酪氨酸酶的抑制作用为竞争性抑制作用，其浓度达４ｍｍｏｌ／Ｌ时，酶活性１００％受到抑制。     

Two types of intraoral distribution of fluorotic enamel

Abstract Different distributions of fluorotic dental enamel within the dentition have been described in the literature. This report describes two patterns of intraoral distribution. In nine Tanzanian low fluorosis communities with a prevalence of pitting fluorosis of less than 2% and in live moderate fluorosis communities with a prevalence of pitting fluorosis of 16–59%, incisors and first molars were the least affected teeth. In four high fluorosis communities with a prevalence of pitting fluorosis of 86–97%, maxillary incisors exhibited lower Thylstrup-Fejerskov Index values than the maxillary canines, premolars and molars. The mandibular teeth exhibited increasing Thylstrup-Fejerskov Index values from the anterior to the posterior region. The curves presenting the intraoral distribution of the severity of dental fluorosis corresponded with the curve presenting the completion time of primary enamel formation of the various tooth types, with the exception of the first molars in high fluorosis communities. The similarity of the curves suggests that the later in life enamel is completed, the higher is the severity of dental fluorosis. This relation seems to be explained by the prevailing feeding and dietary habits, which result in minimal intake of fluoride in the first 18 months of life during breastfeeding, followed by increasing fluoride ingestion in the following years through consumption of tea, seafish and F-containing magadi salt.     

示波极谱滴定法测定盐酸苯海拉明苯妥英钠及其制剂含量

采用示波极谱滴定法测定了盐酸苯海拉明、苯妥英钠及其制剂含量,所得结果均达到药典标准,与非水滴定法或提取后分光光度法比较,本法具有快速、准确、简单、操作方便、免用有机溶剂的优点。     

高碘摄入对SD大鼠钠/碘同向转运体蛋白表达影响的免疫组化研究

目的:动态观察长期高碘摄入对SD大鼠甲状腺细胞钠/碘同向转运体(NIS)蛋白表达的影响.方法:SD大鼠分别饲以去离子水及不同碘浓度的碘化钾水,给碘后1 d及1,2,4,8周处死.测定尿碘、组织碘含量,免疫组织化学方法观察甲状腺细胞NIS蛋白表达水平.结果:高碘摄入可引起甲状腺滤泡细胞膜表面NIS蛋白表达的下降.短期较低浓度的高碘摄入对NiS蛋白的表达无明显影响,而较高浓度的碘摄入则引起NIS蛋白表达的明显减少;长期高碘摄入对NIS蛋白表达的抑制作用,可在机体自我调节机制作用下得以部分恢复,但NIS蛋白表达仍处较低水平.结论:高碘摄入可导致甲状腺细胞表面NIS蛋白表达下降,随摄碘浓度的增加抑制作用增强;不同浓度的碘摄入对NIS蛋白表达的抑制作用表达时间不同.     

乳牙釉质表面氟浓度与患龋状况的关系

目的 探讨牙齿不同部位之间、易患龋牙与非易患龋牙之间牙釉质表面氟浓度有无差异。方法 收集上海、北京和深圳3个地区儿童的下颌乳中切牙45颗,并利用微样酸蚀法分析乳牙釉质表面氟元素的分布。结果 氟浓度从釉质表面到内部有由高到低的变化趋势,牙磨耗是牙齿丧失氟的重要元素,未发现釉质表层氟浓度与龋蚀指数(CSI)、龋补牙数(dft)有相关性(P>0.05)。结论 乳牙釉质表面氟浓度与患龋状况无明显相关性。     

高浓度氟引起SH-SY5Y神经细胞中α7尼古丁受体水平降低

目的：观察氟中毒对神经细胞中α7尼古丁受体的影响。方法：体外培养SH-SY5Y神经细胞，在培养液中加人不同浓度的氟化物，培养48h后测定细胞MTT水平；用放射配体结合实验测定α7尼古丁受体亚型含量；用Westem Bloting方法测定α7尼古丁受体亚单位蛋白水平。结果：经氟处理的神经细胞中MTT水平降低，α7尼古丁受体最大结合容量降低，α7尼古丁受体亚单位蛋白含量减少。结论：氟中毒可引起SH—SY5Y神经细胞中α7尼古丁受体表达降低。