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81.
The application of a circular dichroism (c.d.) detection system in HPLC using a chiral stationary phase is presented. The simultaneous measurement of the absorbance and c.d. signal allows the evaluation of the anisotropy factor (g = Δ/) and thus the determination of the enantiomeric excess (e.e.) of the eluates. When this detection system is used in preparative chiral chromatography the collection of the enantiomeric fractions can be readily optimized.  相似文献   
82.
Serotonin (5-HT) is a mediator (through 5-HT1P receptors) of slow EPSPs in myenteric ganglia of the small intestine. The effect of 5-HT can be mimicked by elevating cAMP; therefore, we tested the hypothesis that the slow EPSP-like response to 5-HT is cAMP-mediated. Guinea pig gut was enzymatically dissociated; myenteric ganglia remained intact and were collected by filtration. Neurons in the isolated ganglia retained their ability to manifest the slow EPSP-like response to 5-HT. Exposure to 5-HT raised the ganglionic level of cAMP (ED50 0.3 μM). This effect was not antagonized by the 5-HT1P antagonist, N-acetyl-5-hydroxytryptophyl-5-hydroxytryptophan amide (100.0 μM), or mimicked by the 5-HT1P agonist, 5-hydroxyindalpine (10.0 μM). Increases in cAMP were also evoked by the 5-HT1 agonist, 5-carboxyamidotryptamine (10.0 μM), the 5-HT2 agonist, (±)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI; 1.0–10.0 μM), and by the 5-HT4 agonists, renzapride (1.0–10.0 μM) and 5-methoxytryptamine (1.0–10.0 μM); however, neither the 5-HT1/5-HT2 antagonists, spiperone, methysergide, and methiothepin, nor the 5-HT4 antagonist, tropisetron (ICS 205–930; 10.0 μM), were able to inhibit the rise in cAMP evoked by these compounds or by 5-HT (0.1–10.0 μM). The 5-HT-evoked elevation of cAMP was antagonized by ketanserin (10.0 μM), which also blocked the effects of 5-methoxytryptamine and DOI, but not those of renzapride. The effective concentration of DOI, however, was higher than that needed for activation of 5-HT2 receptors, and Northern analysis using a cDNA probe encoding the rat 5-HT2 receptor failed to reveal the presence of 5-HT2 mRNA in myenteric ganglia, although it hybridizes with mRNA of the right size in the guinea pig brain. Compounds that failed to change levels of cAMP or to antagonize the action of 5-HT included 8-hydroxy-di-n-propylamino tetralin, R58639, R88226, and sumatriptan. It is concluded that the receptor responsible for the 5-HT-induced rise in cAMP in ganglia isolated from the guinea pig myenteric plexus is not a known subtype of 5-HT receptor. Since the pharmacology of this novel receptor is different from that of the slow EPSP-like response to 5-HT, the receptor probably does not mediate the slow EPSP. © 1993 Wiley-Liss, Inc.  相似文献   
83.
84.
目的观察Agilent 2100 Bioanalyzer 芯片分析系统(以下简称Bioanalyzer)在基因差异表达研究中的应用。方法应用限制性显示技术分别从正常和热休克处理后的酿酒酵母细胞中分离出cDNA片段,然后再用Bioanalyzer和传统的琼脂糖凝胶电泳技术对RD-PCR产物进行检测分析。结果Bioanalyzer能更快速、敏感地分离和显示差异表达的基因片段,并且通过对差异片段进行定量比较,发现了数个表达有明显差异的基因片段。结论Bioanalyzer在基因差异表达研究中具有重要的应用价值。  相似文献   
85.
BACKGROUND AND OBJECTIVES: Evaluation of long-term results using a thermal balloon endometrial ablation technique to treat menorrhagia and hypermenorrhea, considered dysfunctional uterine bleedings. METHODS: A single-arm, prospective study with long-term follow-up of 48 months at the department of obstetrics and gynecology, University of Kiel, Germany. Following hysteroscopic evaluation of the uterine cavity and fractionated curettage, the Cavaterm endometrial thermal ablation technique was performed on 70 patients over the age of 40 with menorrhagia and hypermenorrhea in whom medical treatment had previously failed. The study included a group of 10 patients with adenomyosis and uterine fibroids. RESULTS: In 65 patients, a complete 48-month follow-up evaluation was possible: 58% of patients reported amenorrhea and 33% hypomenorrhea. Nine percent of patients remained eumenorrheic. Fifty percent of the small group with failed indications for the procedure had to undergo a hysterectomy. CONCLUSIONS: The Cavaterm thermal coagulation system in the earlier mode of application (15 minutes at a temperature of 70 degrees C and a pressure of 200 mm Hg) is a safe and highly effective method of endometrial ablation resulting in a minimal amount of posttreatment menstrual bleeding.  相似文献   
86.
目的 :研究老年人不同疾病时骨密度 (BMD)的分布情况。方法 :用DXADAS 6 0 0EX型骨密度仪对183例老年患者进行左侧远程桡骨加尺骨BMD检测。结果 :内分泌疾病组、消化道疾病组和其它疾病组的患病率分别为 72 7% ,2 0 6 %和 31 4 %。T值比较 :三组差异明显 (P <0 0 0 1)。累积骨丢失率 (ABLR)比较 :前一组明显高于后两组病人 (P <0 0 1)。BMD比较中 ,内分泌和其它疾病组明显低于消化道疾病组 (P <0 0 0 1)。相关分析显示 ,内分泌和消化道疾病组的年龄变化与BMD呈正相关 (r =0 5 19P <0 0 0 1和r =0 5 89P <0 0 0 1) ,内分泌疾病组和其它疾病组的体重变化与BMD呈正相关 (r=0 918P <0 0 0 1和r =0 338P <0 0 0 1)。结论 :老年人骨质疏松 (OP)患病率以内分泌疾病组最高 ,消化道疾病组较低 ;随年龄和体重增加 ,BMD降低加重。  相似文献   
87.
马来酸罗格列酮胃漂浮型缓释片的研究   总被引:10,自引:0,他引:10       下载免费PDF全文
目的:根据流体动力学平衡控释原理(HBS)研制了马来酸罗列酮胃漂浮型缓释片。方法;以体外释放度和漂浮情况为筛选指标,采用单因素考察和正交试验设计相结合, 对胃漂浮缓释片的处方、制备工艺及体外释放条件进行优化筛选;采用γ闪烁照相技术对优化处方的内漂浮情况进行胃内动态观察。结果:马来酸罗格列酮胃漂浮缓释片在释放介质中迅速起漂,持漂时间超过12h,12h达最大累积释放;初步确定在胃内滞留时间达3h以上。结论:优化处方的释放过程符合Higuchi方程,释放机制为异常扩散;胃漂浮片在胃滞时间明显长于普通片。  相似文献   
88.
We propose a haphazard branching theory to support the concept of bronchopulmonary malinosculations, and we apply this theory to classify congenital bronchopulmonary vascular malformation (BPVM) based on the anatomical results we have found. Between January 1990 and December 1997, a total of 22 pediatric patients (10 male and 12 female), aged 2 days to 14 years (median, 19.6 months), with congenital BPVM were enrolled in this retrospective study. Study modalities include the clinical features and plain chest films (n = 22) plus at least two of the following: echocardiography (n = 13), barium esophagraphy (n = 2), bronchoscopy (n = 4), contrast bronchography (n = 8), high-resolution direct coronal CT (n = 1) and electron beam or ultrafast CT (n = 1) of the chest, MRI (n = 10), MRA (n = 1), contrast cineangiocardiography (n = 9), surgery (n = 11), or autopsy (n = 2). The salient clinical features were recurrent lung infections in 14 patients, acute respiratory distress in 13, associated cardiovascular malformations in 8, dextroversion in 7, congestive heart failure in 7, dextrocardia in 4, and complex congenital heart diseases in 4. There were abnormal openings (malinosculations) of the pulmonary airway in 20 patients: to an artery in 12, to a vein in 8, and to the lung parenchyma in 9. These 22 patients with congenital BPVM can be classified into bronchial malinosculation (10 cases), arterial malinosculation (2 cases), and bronchoarterial malinosculation (10 cases). Congenital BPVM can be classified in terms of bronchopulmonary malinosculation based upon a haphazard branching theory, in which abnormal communications between two independent systems (primitive foregut system and aortic-pulmonary arch system) occurred coincidentally rather than causally.  相似文献   
89.
90.
通过 PCR获得 E.coli B谷胱甘肽合成酶系基因 ( gsh I,gsh II)片段 ,结合定点突变稀有起始密码子 ,设定 gsh I与 gsh II位置与距离 ,构建双顺反子重组表达载体 p Trc99A/gsh I- gsh II,建立GSHI、GSH- II蛋白表达体系。结果表明 :以 0 .0 8mmol/L IPTG于 2 8℃诱导工程菌 E.coli BL2 1( DE3) ( p Trc99A/gsh I- gsh II) ,GSH- I、GSH- II蛋白比为 4.5∶ 1 ( m∶ m)时谷胱甘肽合成能力最高 ,达到每克湿菌体 8.5 mg。通过构建单顺反子重组表达载体 p Trc99A/gsh I、p Trc99A/gsh II测定GSH- I与 GSH- II蛋白的最适配比 ,结果表明 :在 GSH- I、GSH- II蛋白总量恒定的情况下 ,要提高谷胱甘肽产率 ,两者比例以 3∶ 1~ 6∶ 1为宜  相似文献   
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