硝基胍的毒性研究

目的对硝基胍的毒性进行研究,为制订卫生标准提供依据.方法包括急性毒性试验、蓄积毒性试验及亚慢性毒性试验.结果硝基胍大鼠经口LD50为8 066 mg/kg,小鼠经口LD50为10 044 mg/kg,蓄积系数大于5.3.亚慢性毒性试验中,高剂量组雄性大鼠在染毒第3周和第8周,体重有明显的负增长(P＜0.05);高剂量组雄性大鼠睾丸脏器系数明显高于对照组(P＜0.05);红细胞免疫功能测定结果显示,中、高剂量组大鼠红细胞受体花环率分别为10.00±2.37和7.50±2.66,明显低于对照组(P＜0.05,P＜0.01).其余各项指标未见明显改变.结论硝基胍属于微毒级毒物,轻度蓄积,亚慢性毒性试验对动物有一定的影响.     

A simple method for screening assessment of acute toxicity of chemicals

We proposed a simple method for screening assessment of acute oral and dermal toxicity using only three rats and mice of each sex at each dose level. Animals were first treated with chemicals at a dose of 2000 mg/kg and were carefully observed for compound-related morbidity and mortality. If none of the animals died, the following toxicity tests were suspended. If some of the animals died, toxicity tests at doses of 200 and 20 mg/kg were performed. The approximate LD₅₀ values calculated by this method showed little difference between two separate laboratories and were in good agreement with LD₅₀ values reported in the literature. Our toxicological data also showed that LD₅₀ values were about 2–2.5 times the MNLD (maximum non lethal dose) in acute oral and dermal toxicity. This meant that a chemical could be regarded as having an LD₅₀ of about 4000 mg/kg or higher when there was no mortality at the dose of 2000 mg/kg. A chemical with such low toxicity would not require further testing for lethal effects. Therefore, this simple method combining the fixed-dose procedure with the limit test is suitable for determination of approximate LD₅₀ values of chemicals and for screening for necessity for classical full LD₅₀ test using many animals.This work was supported by a grant from Ministry of Health and Welfare in Japan (No. 467 and 511)     

Effect of electrical stimulation on gastric electrical activity,motility and emptying

Abstract The aim was to measure the effect of gastric electrical stimulation on the frequency of canine antral pacesetter potentials (PPs), the strength of antral contractions, and the rate of gastric emptying while fasting, after feeding and with pentagastrin stimulation. Four conscious dogs with a stimulating electrode placed 10 cm proximal to the pylorus and recording electrodes and strain gauges placed 7, 5 and 3 cm proximal to the pylorus underwent myoelectric and strain gauge recordings while fasting, after feeding (250 ml 5% dextrose labelled with polyethylene glycol), and during pentagastrin infusion (0.5 μg kg^?1 min^?1) on four separate days. On each day, electrical stimulation was done using one of four stimulation frequencies (0, 6, 30 and 1200 stimuli per minute ***[s.p.m.]). Stimulation at 6 and 30 s.p.m. increased the fasting and fed PP frequency, whereas 1200 s.p.m. stimulation did not. Feeding decreased the maximum driven frequency, and pentagastrin increased it. Neither the motility index nor the gastric emptying rate were consistently changed by stimulation at any frequency. In conclusion, canine proximal antral stimulation at 6 and 30 s.p.m. sped PP frequency during fasting and after feeding, but stimulation over a wide range of frequencies had little effect on gastric contractions and emptying.     

甘肃省1995年急性弛缓性麻痹病例病毒学监测

甘肃省１９９５年共报告１５岁以下儿童急性弛缓性麻痹（ＡＦＰ）病例９０例，发病率为１．３２／１０万。省脊髓灰质炎（脊灰）实验室收到ＡＦＰ病例的粪便标本共７９例，占８８％；双份合格粪便标本采集率为６８％（６１／９０）；粪便标本７天内送省脊灰实验室的占６５％（５２／７９）收到粪便标本后７天内分离培养的占８９％（７０／７９）；分离培养结果及时报告率为８７％（６９／７９）。病毒分离阳性率１３．９２％（１１／７９），其中脊灰病毒（ＰＶ）Ⅱ型５株，Ⅲ型１株，非脊灰肠道病毒（ＮＰＥＶ）５株。收到ＡＦＰ病例密切接触者粪便标本３ｌ８份，病毒分离阳性率５．６６％（１８／３１８），其中ＰＶⅡ型８株，ＮＰＥＶ１０株。全部送检粪便标本ＮＰＥＶ分离率３．７８％（１５／３９７）。所分离的ＰＶ均为疫苗株，且Ⅱ型居多。     

急性肠系膜静脉血栓形成16例临床分析

目的　分析急性肠系膜静脉血栓形成 (ASMVT)的临床特征和诊断方法。方法　对北京友谊医院 1985年 10月至 2 0 0 2年 10月确诊的 16例ASMVT的临床资料进行分析 ,并结合文献 ,总结ASMVT的临床特征和诊断方法。结果 16例ASMVT患者 ,年龄 19～ 6 4岁 (平均 4 5 9岁 )。主要症状有腹痛 ( 16 / 16 )、腹胀 ( 16 / 16 )、呕吐 ( 10 / 16 )、发热 ( 8/ 16 ) ,主要体征有腹部膨隆 ( 16 / 16 )、腹膜刺激征( 16 / 16 )。误诊率 75 % ( 12 / 16 ) ,死亡率 4 4 % ( 7/ 16 )。结论　ASMVT的临床表现有一定的特征 ,早期彩色超声检查、诊断性腹腔穿刺、结合CT或肠系膜上动脉造影异常发现可对ASMVT做出正确的诊断 ,早期手术可以降低死亡率     

紫杉醇诱导体外培养胃腺癌细胞系SGC-7901凋亡

目的：研究紫杉醇对胃腺癌细胞系SGC—7901的凋亡诱导作用。方法：紫杉醇不同浓度、不同作用时间分别处理胃腺癌细胞系SGC—7901。采用MTT法测定胃癌细胞的生长抑制率，通过组织学观察、TUNEL等手段检测胃腺癌细胞系SGC--7901细胞凋亡情况。结果：紫杉醇对胃腺癌细胞系SGC—7901有明显的抑制作用，并在一定剂量和时间范围内诱导胃腺癌细胞系SGC—7901凋亡，随着药物浓度的增加及时间的延长，凋亡细胞明显增多，当紫杉醇作用浓度为20μmol/L以上时，细胞出现破碎、坏死。结论：紫杉醇对胃腺癌细胞系SGC—7901有明显的抑制作用，诱导凋亡是其发挥抗癌作用的机制之一。     

The herbal preparation STW5 (lberogast®) has potent and region-specific effects on gastric motility

Functional dyspepsia (FD) is amongst the most common functional gastrointestinal disorders. Symptomatic treatment includes the use of herbal preparations whose effects on gastric motility are unclear. The present study aimed at investigating the effects of STW 5 (Iberogast), a fixed combination of hydroethanolic herbal extracts, on gastric motility in vitro. Muscle strips from guinea-pig gastric fundus, corpus and antrum were set up in organ baths either in circular or longitudinal orientation. Addition of ethanol-free STW 5 to the organ baths (32-512 microg mL(-1)) dose-dependently evoked a sustained and reversible relaxation of circular and longitudinal fundus and corpus muscle strips without changes in phasic activity. In contrast, antral muscle strips responded to STW 5 with a significant increase in the contractile force of phasic contractions without changes in tone. All effects were resistant to tetrodotoxin (0.5 micromol L(-1)), atropine (1 micromol L(-1)), omega-conotoxin GVIA (0.5 micromol L(-1)), capsaicin (1 micromol L(-1)) or L-NAME (100 micromol L(-1)), suggesting that neither nerves nor nitric oxide pathways were involved. These data demonstrate that STW 5 profoundly alters gastric motility in a region-specific but not layer-specific manner and thus implicates Iberogast in the treatment of FD patients suffering from motility disorders with impaired fundus accommodation and/or antral hypomotility.     

How reproducible is cutaneous electrogastrography? An in-depth evidence-based study1

AIM: To check on reproducibility of parameters of the cutaneous electrogastrogram registered at a close or a distant time span. METHODS: Twenty-two volunteers recruited by an advertisement (11 females and 11 males, median age 25 years, range: 18-35) underwent three surface electrogastrography examinations of which two were taken on consecutive days and the third one was accomplished at least 2 weeks before or after the two other sessions. The examination involved a 30-min fasted recording, followed by a 90-min postprandial registration after intake of a 394-kcal mixed solid-liquid test meal. RESULTS: Parameters of the electrogastrogram pertaining to the frequency of the gastric slow waves exhibited good to moderate reproducibility, whereas fair reproducibility characterized parameters expected to describe the power of gastric slow waves. With the exception of the difference fed minus fasted power (DeltaDP), in no instance was the medium term reproducibility any worse than the short term one. Categorical data analysis revealed that the relative time share of normogastria postprandially exhibited a better reproducibility than in the fasted period. The Cohen's kappa-value of 0.459 for the DeltaDP for the medium term reproducibility placed this parameter within the range of moderate agreement between repeat examinations. Of the two two-parameter combinations considered, the alliance of the fasted and fed normogastria performed worse than any of those parameters considered alone, whereas a combination of the DeltaDP with the fed-state normogastria revealed a kappa-value amounting to 0.510 for the medium term reproducibility. CONCLUSIONS: The feasibility of some electrogastrographic parameters to convey clinically useful information may be hampered by their fair reproducibility. Recoding of parameters of the cutaneous electrogastrogram from primary continuous to secondary categorical may help achieve a better agreement between repeat examinations.