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.     

空管药物疗法治疗牙髓病和根尖周病疗效观察

用ＳＭＴＤ复合药物对牙髓病和根尖周病实施空管药物疗法。７８例１０３颗获得完整随访资料患牙经两年观察，９２．２％治愈率。文章介绍了治疗方法，讨论了空管药物疗法的愈合机理、优点、失败原因及其预防措施。     

Pharmacokinetics of Controlled Release and Immediate Release Morphine Sulphate Tablets after a Single Dose and Multiple Doses in Chinese Volunteers

健康志愿者１０名，随机交叉口服硫酸吗啡控释片（ＣＲＭＳ）３０ｍｇ（３０ｍｇ×１）和硫酸吗啡普通片（ＩＲＭＳ）２０ｍｇ（１０ｍｇ×２），分别于服药前后各时点取静脉血，用ＧＣＭＳ测定血浆中吗啡含量。以药代软件程序处理，分别求得ＣＲＭＳ和ＩＲＭＳ的Ｃｍａｘ为１９．３８±３．８０和２１．２７±６．２１ｎｇ／ｍｌ；ｔｍａｘ为２．３６±０．３７ｈ和０．５５±０．１６ｈ；ｔ１／２β为３．５３±０．８７ｈ和３．０３±０．７４ｈ，曲线下面积ＡＵＣ为１４５．１５±１７．６５和９３．０８±１６．６５ｎｇ·ｈ／ｍｌ。癌症病人多次口服硫酸吗啡至稳态，ＣＲＭＳ和ＩＲＭＳ的峰浓度分别为２７．４３±０．３３ｎｇ／ｍｌ，２２．６８±０．１６ｎｇ／ｍｌ；谷浓度分别为１９．４５±１．４４ｎｇ／ｍｌ；１８．１４±０．４９ｎｇ／ｍｌ。     

毛细管电泳技术快速检测p53基因点突变

目的：探讨利用毛细管电泳技术快速检测p53基因点突变的临床应用价值。方法：采用毛细管电泳作SSCP分析，检测20例结肠癌肿瘤标本p53基因第7外显子PCR扩增产物，并与传统的聚丙烯酰胺凝胶电泳结果进行比较，最后用DNA序列测定判断其准确性。结果：20例结肠癌标本中，毛细管电泳技术检测出5例标本(Ca4，Ca6，Ca7，Ca8，Ca14)有突变，而凝胶电泳结合银染技术仅检出4例标本(Ca4，Ca6，Ca7，Cal4)有突变，测序证实经毛细管电泳所检出的5例标本均存在点突变。结论：对于PCR产物的单链构象多态性分析，毛细管电泳技术是一种更加快速、简便、敏感的方法，可应用于临床筛查基因点突变。     

用β－CD单分子胶束荧光技术监测秦艽中龙胆苦甙血药浓度

本文使用β－ＣＤ单分于胶束荧光技术，对甘肃道地药材秦艽中龙胆苦甙在免血中吸收代谢，进行了２４ｈ监测绘制药时曲线，效果良好．     

北方汉族人群维生素D受体基因Bsm I位点多态性与前列腺癌易感性的相关性分析

目的 :研究低发病的中国汉族人群维生素D受体基因 (VDRG)BsmⅠ 位点单核苷酸多态性 (SNP)与前列腺癌的关系 ,探讨不同种族前列腺癌发病的基因差异。　方法 :收集中国北方地区汉族人群 10 3例前列腺癌病人及10 6例健康对照者外周血标本 ,应用变性高效液相色谱 (DHPLC)检测VDRG第 8内含子BsmⅠ多态位点 ,并对该位点SNP分布进行分析。　结果 :BsmⅠ 多态位点bb、Bb、BB基因型和等位基因在北方地区汉族前列腺癌病人及对照者中的分布频率差异无显著性 (P >0 .0 5 ) ,基因型分布频率分别为 92 .2 3%、7.77%、0和 94.34 %、5 .6 6 %、0 ;等位基因B、b分别为 3.88%、96 .12 %和 2 .91%、97.0 9%,而与高发病人群的分布相比有显著不同。　结论 :VDRGBsmⅠ多态性在低发病的中国汉族人群与前列腺癌无相关 ,其分布与高发病人群有明显差异 ,提示VDRGBsmⅠ多态性可能是前列腺癌发病种族差异的原因之一。     

High level production of soluble single chain antibodies in small-scale Escherichia coli cultures

We have investigated the effect of growth and induction conditions on the production of soluble single-chain Fv antibody fragments in Escherichia coli under the control of wt lac promoter. The scFv was directed into the periplasmic space by a pelB leader sequence. Addition of sucrose to the medium gave a 15–25-fold increase in the yield of soluble scFv-phOx (3.0 mg/l) for bacterial shake-tube cultures and an increase of 80–150-fold (16.5 mg/l) for shake-flask cultures. Using flask culture in the presence of 0.4 M sucrose, a significant amount of scFv was released into the medium. We found that the scFv could be made to accumulate in the periplasm or be secreted into the medium by simply changing the incubation conditions and the concentration of the inducer. The ratio between soluble antibody fragments and insoluble scFv aggregates proved to be dependent on the strength of the promoter. Lowering the incubation temperature below 20°C had no effect on the yield of soluble antibody fragments in the periplasm, but they were no longer secreted into the medium. An example of high level production in shake-flask cultures and one-step purification by immobilized metal affinity chromatography (IMAC) is described for a soluble scFv specific for the T cell surface antigen CD3. The biological activity of the purified anti-CD3 scFv was demonstrated by flow cytometry. This method should be especially useful for the functional screening of a large number of clones in small-scale cultures.     

Internal and external information processing by lateral hypothalamic glucose-sensitive and insensitive neurons during bar press feeding in the monkey

Single neuron activities in the lateral hypothalamic area (LHA) were recorded during bar press feeding task in the monkey. First registered neurons were sorted into 2 groups, glucose-sensitive (GS) and glucose-insensitive (GIS) neurons, depending on their glucose sensitivity. Then firing variations to feeding, electrophoretically applied catecholamines and opiate, and to odor and taste stimuli were investigated. GS neurons responded to dopamine, noradrenaline and morphine more often than GIS neurons. In feeding task GS neurons responded during bar press (BP) and reward (RW) periods with long-lasting inhibition of firing and at cue tone (CT) with transient inhibition, while GIS neurons responded during BP and RW periods mainly with excitation and at cue light (CL) with excitation. A majority of GS neurons responded to both odor and taste stimuli more often than GIS neurons. Data suggest that these two kinds of neurons in the LHA may be involved in different functional aspects of feeding: GS neurons, mainly in internal information processing and reward mechanism, and GIS neurons, in external information processing and motor aspects.     

Impact of photon energy recovery on the assessment of left ventricular volume using myocardial perfusion SPECT

BACKGROUND: Photon energy recovery (PER) is a spectral deconvolution technique validated for scatter removal in patients and phantom studies. The purpose of this study was to examine the impact of PER on left ventricular volume measurement based on myocardial perfusion single photon emission computed tomography (SPECT). METHODS AND RESULTS: SPECT acquisitions were performed by use of a static cardiac phantom and in 25 patients after a rest injection of technetium 99m sestamibi by use of multiple energy windows (126-136, 137-144, and 145-154 keV). Data were successively reconstructed with and without PER, by use of iterative reconstruction and post-processing filtering (Butterworth filter; order, 5; cutoff, 0.30 cycles/pixel). Image contrast was evaluated in reconstructed data, and volumes were calculated by use of QGS. PER increased reconstructed image contrast from 62% +/- 2.7% to 84.3% +/- 5.7% in the phantom studies (P <.0001) and from 49% +/- 2% to 73% +/- 2% in patients (P <.0001). Although it remained underestimated (P <.0001), phantom volume was higher after PER correction compared with uncorrected data (50.9 +/- 0.8 mL vs 44.6 +/- 1 mL, P <.0001). The error in volume measurement was decreased by PER correction (16.6% +/- 1.3% vs 27% +/- 1.7% [uncorrected data], P <.0001). In patients, left ventricular volume increased from 83 +/- 10 mL to 91 +/- 10 mL (P <.0001), and the PER-induced volume increase was correlated with the image contrast increase (r = 0.61, P =.001). Finally, the percentage of volume increase was higher in patients with small left ventricular volumes. CONCLUSIONS: PER has a significant impact on image contrast and left ventricular volume measurement by use of perfusion SPECT. PER improves the accuracy of phantom volume assessment. In patients, volume increase is correlated to image contrast increase and is higher in those with small ventricles.     

响洪甸放射性废物坑放射卫生学调查及评价

本文调查了一个铀水冶厂放射性废物坑的污染情况,发现该坑周围农田及坑附近淠史杭大灌渠水、泥等均受到不同程度污染。这表明,即使处理小型铀水冶厂的放射性废物,在选址、掩埋等各个环节也都应严格做到科学、合理,并且还要做好掩埋后的管理工作。