Comparison of simultaneous pH measurements made with 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) and pH-sensitive microelectrodes in snail neurones

 We have evaluated the pyrene-based ratiometric fluorescent dye, 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS), by using it in conjunction with glass pH-sensitive microelectrodes to measure intracellular pH (pH_i) in voltage-clamped snail neurones. Intracellular acidification with propionic acid, and alkalinization following the activation of H⁺ channels allowed the calibration of the dye to be compared with that of the pH microelectrode over the pH range 6.50–7.50. HPTS calibrated in vitro and glass pH-sensitive microelectrodes produced similar absolute resting pH_i values, 7.16±0.05 (n=10) and 7.17±0.06 (n=9) respectively in nominally CO₂/HCO₃ ^–-free saline. At both extremes of the pH range there were small discrepancies. At acidic pH_i, 6.87±0.09 (n=5), the intracellular HPTS measurement differed by –0.08±0.03 pH units from the pH-sensitive microelectrode measurement. At alkaline pH_i,7.32±0.10 (n=5), HPTS measurements produced pH values that differed by +0.07±0.04 pH units from those of the pH-sensitive microelectrode. Some of the discrepancy could be accounted for by the slow response of the recessed-tip pH-sensitive microelectrode (time constant 77±15 s, n=3). Further experiments showed that HPTS, used at an intracellular concentration of 200 μM to 2 mM, did not block activity-dependent pH_i changes. The intracellular HPTS concentration was calculated by measurement of intracellular chloride during a series of HPTS-KCl injections. Comparison of HPTS with 2′,7′-bis(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF), at the same concentration, showed that HPTS produces a larger change in ratio over the pH range 6.00–8.00. Received: 19 February 1998 / Received after revision and accepted: 22 April 1998     

Differential action of TEA+ on two K+-current components of a molluscan neurone

Summary Snail neuronal membranes have two distinct outward current components. Both components are carried by K⁺-ions. They are, however, differentially influenced by Tetraethylammonium. At low concentrations in the external bath (5 mM), TEA⁺ blocks the delayed outward current only. The fast outward current is affected if higher TEA⁺ concentrations are used. Intracellular TEA⁺, applied iontophoretically, blocks both current components in a similar manner.     

Parathyroid hormone enhances calcium current in snail neurones — Simulation of the effect by phorbol esters

Effects of parathyroid hormone substance (PTH) on the voltage-activated calcium current (I _Ca) were studied on intracellularly perfused neurones of the snail, Helix pomatia, under voltage-clamp conditions. Application of 0.1 nM PTH produced a marked potentiation of the current. The effect developed slowly (60–70 min) and remained after removal of PTH. Potentiation could be observed in most neurones, but varied considerably from cell to cell; in some neurones I _Ca was increased 2- to 3-fold. Addition of ethylenebis(oxonitrilo)tetraacetate (EGTA, 10 mM) to, or removal of adenosine 5-triphosphate (ATP, 2 mM) from the intracellular perfusing solution resulted in a suppression or attenuation of the potentiating effect. The effect could be reproduced by the synthetic 1–34 amino acid fragment of PTH. Extracellularly applied protein kinase-C (PK-C) activator phorbol ester phorbol 12-myristate 13-acetate (PMA, 0.1–10 M) produced a similar slow increase in I _Ca (up to 1.5- to 2-fold), while its inactive analogue (4-phorbol ester) had no effect on I_Ca. The effects of PTH and PMA were not additive. PK-C inhibitors [1-(5-isoquinoline-sulphonyl)-2-methylpiperazine hydrochloride] (H-7, 100 M) and staurosporine (100 M) as well as calcium channel antagonists Cd²⁺, verapamil, nifedipine and nimodipine depressed the effect of PTH. The chloride channel blocker 4,4-diisothiocyanato-stilbene-2,2-disulphonic acid (DIDS, 1 mM) did not affect the potentiating action of PTH. Activation of the adelylate cyclase system also potentiated I _Ca in some neurones, but this effect had a different time course and was additive to the effect of PTH. A conclusion is made that activation of PK-C may mediate the slowly developing enhancement of I _Ca by PTH.     

Snail与E-cadherin在食管癌中的表达及临床意义

目的研究食管癌中转录因子Snail及黏附因子E-cadherin的表达,并探讨与食管癌浸润转移的关系。方法采用免疫组化SP法检测68例食管癌组织和40例癌旁组织中Snail,E-cadherin的表达情况,分析两者在不同分化程度的食管癌中的表达,以及与临床病理因素之间的关系。结果食管癌组织Snail阳性率(82.4%)显著高于癌旁组织(42.5%)(p<0.05),Snail的表达与食管癌不同分化程度、浸润深度、淋巴结转移及远处转移有关(p<0.05)。食管癌组织E-cadherin的阳性率(36.7%)显著低于癌旁组织(87.5%)(p<0.05),E-cadherin的表达与食管癌不同分化程度、浸润深度、淋巴结转移、临床分期及远处转移有关(p<0.05)。食管癌组织中Snail与E-cadhrin的表达呈负相关(p<0.05)。结论Snail蛋白高表达与E-cadherin蛋白低表达可能参与食管癌浸润转移的发生,并且联合检测可作为其重要生物学标志,有助于食管癌早期诊断和预后评价。     

Snail蛋白在骨肉瘤中的表达及临床意义

目的 观察Snail蛋白在骨肉瘤中的表达,探讨其在骨肉瘤发生、发展中的作用.方法 采用免疫组化SP法检测骨肉瘤组织42例、骨软骨瘤10例中Snail蛋白的表达.结果 ①Snail蛋白在骨肉瘤中表达高于骨软骨瘤组织中的表达,差异有统计学意义(P＜0.01);②Snail蛋白在骨肉瘤组织中的表达与软组织浸润、Ennekin...     

海南省广州管圆线虫中间宿主感染现状调查

目的 了解海南省广州管圆线虫中间宿主感染现状,为继续开展防治工作提供科学依据。方法 2018—2019年,按海南省的地理方位和水系分布,抽取与2006年一致的5个调查点,采集广州管圆线虫中间宿主螺蛳,以“肺检法”结合“匀浆法”检测中间宿主并查找广州管圆线虫幼虫。结果 2018—2019年,在5个调查点共检测野外采集螺蛳1 597只,广州管圆线虫幼虫平均感染率为6.39%(102/1 597)。其中福寿螺、褐云玛瑙螺、蜗牛和蛞蝓感染率分别为7.95%(43/541)、6.45%(34/527)、15.91%(7/44)和3.71%(18/485)。福寿螺感染率琼中县较高为9.57%(11/115),海口较低为4.90%(5/102),各地感染率差异无统计学意义(χ²=5.63,P>0.05)。褐云玛瑙螺的感染率儋州市较高为16.50%(17/103),三亚市最低为0.95%(1/105)。各地感染率差异有统计学意义(χ²=12.89,P<0.05)。蜗牛感染率儋州市最高为33.33%(5/15),三亚市最低为0,各地感染率差异有统计...     

武汉市综合治理垸内钉螺孳生地效果及效益分析

目的对武汉市垸内综合治理控制血吸虫病流行的效果及费用效益进行分析,为决策和评价提供科学依据。方法根据不同地理特点,以环境改造为主,采用沟渠硬化、开新填旧、建鱼池等方法,辅以药物杀灭对垸内钉螺孳生地进行全面综合治理。收集治理前后螺情、人畜病情以及项目费用、疫区经济状况等相关资料,计算螺情、病情指标下降率以及单位效果费用、净效益、费用效益比,进行防治效果评价和费用-效果、费用-效益分析。结果经综合治理,全市有螺处数、有螺面积分别下降了79．93％,85．73％;垸内各流行村人群粪检阳性率下降了58．82％;耕牛粪检阳性率下降了73．14％。项目血防综合效果指数为71．50,费用效益比为1：2．92,净效益费用比为1．92。结论垸内钉螺孳生地综合治理,有效控制了血吸虫病流行,是湖沼型垸内亚型地区控制并消灭血吸虫病的有效对策和措施。     

E-cad、Snail表达与Dukes B期大肠癌浸润、转移、预后的关系

目的研究E- cad、Snail表达与大肠癌侵袭、转移和预后的关系。方法采用免疫组化EnVision法,分别检测E- cad、Snail在正常大肠黏膜上皮、大肠腺瘤及大肠癌患者癌组织中的表达。结果 E- cad的表达与肿瘤分化程度、浸润深度、静脉、淋巴管侵犯、淋巴结转移与否及Dukes分期状况密切相关（均P＜0.05）,而与年龄、性别、肿瘤大小、肿瘤病理类型无相关性（均P＞0.05）。45例Dukes B期的大肠癌患者中7例E- cad染色阴性,其1、3、5年生存率分别为85.71％、57.14％、0.00％;38例为中度阳性或强阳性,其1、3、5年生存率分别为97.37％、65.79％、39.47％,两者比较有统计学差异（P＜0.01）。Snail表达与肿瘤病理类型、分化程度、浸润深度、静脉、淋巴管侵犯、淋巴结转移与否及Dukes分期明显相关（均P＜0.05）,而与年龄、性别、肿瘤大小无相关性（均P＞0.05）。45例Dukes B期的大肠癌患者中26例Snail染色阴性,其1、3、5年生存率分别为100.00％、69.23％、42.31％;19例为中度阳性或强阳性,其1、3、5年生存率分别为89.47％、57.89％、26.32％,两者比较有统计学差异（P＜0.01）。多因素分析结果显示：肿瘤淋巴结转移、Dukes分期、E- cad表达强度、Snail表达强度可预示患者术后生存情况（均P＜0.05）。E-cad与Snail在大肠癌组织中的表达呈显著负相关（r=-0.508,P＜0.01）。结论 E- cad与Snail可作为大肠癌患者的独立预后指标,预示患者术后生存情况。Dukes B期大肠癌患者中,E- cad阴性者预后明显较阳性者为差;Snail阳性者的预后明显较阴性者为差。     

Effect of Rapamycin on TGF-β1- induced epithelial-mesenchymal transition in LoVo colonic adenocarcinoma cells

Objective:To investigate the effect of Rapamycin on epithelial-mesenchyrnal transition(EMT) of LoVo colonic adenocarcinoma cells in vitro.Methods:Cultured LoVo colonic adenocarcinoma cells were divided into three groups: negative control group,EMT-inducing group(TGF-β1) and EMT-interfering group(TGF-β1 plus Rapamycin).E-cadherin expression in LoVo cells was detected by Western Blot,while the expression of vimentin was evaluated through immunocytochemistry.The Snail mRNA in LoVo cells was examined by RT-PCR.Results:TGF-β1 induced LoVo cell switching from polygonal to spindle-shaped.TGF-β1 enhanced the expression of vimentin,but lowered the level of E-cadherin.In contrast,Rapamycin impaired the transition induced by TGF-β1.Rapamycin dramatically abrogated TGF-β1-induced vimentin expression and restored E-cadherin expression in LoVo cells.Rapamycin significantly repressed the up-regulation of Snail mRNA expression induced by TGF-β1.Conclusion:Rapamycin dramatically abrogated TGF-β1 induced Snail mRNA expression in LoVo cells,hence inhibiting EMT of these cells in vitro.     

血水草杀螺成分-血水草生物碱(ECA)的提取

目的 从血水草中提取杀螺有效成分—血水草生物碱(ECA)。方法 采用70％乙醇渗漉提取，用减压浓缩、酸解、盐析等方法纯化，提取ECA原粉。结果 ECA原粉的提取率为1.009％．结论 本提取方法可靠，设备及工艺流程简单，提取条件易控制，且成本低，便于开发应用。