Mechanisms of actions of hydrogen sulphide on rat distal colonic epithelium

BACKGROUND AND PURPOSE

The aim of this study was to clarify the mechanisms by which hydrogen sulphide (H₂S) affects ion secretion across rat distal colonic epithelium.

EXPERIMENTAL APPROACH

Changes in short-circuit current induced by the H₂S-donor, sodium hydrosulphide (NaHS; 10 mmol·L⁻¹), were measured in Ussing chambers after permeabilization of the apical membrane with nystatin. Cytosolic Ca²⁺ concentration ([Ca²⁺]_i) and Ca²⁺ in intracellular stores were measured with fluorescent dyes. Changes in mitochondrial membrane potential were estimated with rhodamine 123.

KEY RESULTS

NaHS had a biphasic effect on overall currents across the basolateral membrane: an initial inhibition followed by a secondary stimulation. Both a scilliroside-sensitive action on the Na⁺-K⁺-ATPase and modulation of glibenclamide-sensitive and tetrapentylammonium-sensitive (i.e. ATP-sensitive and Ca²⁺-dependent) basolateral K⁺ channels were involved in this action. Experiments with rhodamine 123 revealed that NaHS induced a hyperpolarization of the mitochondrial membrane. NaHS evoked a biphasic change in [Ca²⁺]_i, an initial decrease followed by a secondary increase, known to be mediated by the release of stored Ca²⁺. Initial falls in [Ca²⁺]_i were not mediated by a sequestration of Ca²⁺ in intracellular Ca²⁺ storing organelles, as the Mag-Fura-2 signal was unaffected by NaHS. Falls in [Ca²⁺]_i were inhibited by 2′,4′-dichlorobenzamil, an inhibitor of the Na⁺-Ca²⁺-exchanger, and attenuated in Na⁺-free buffer, suggesting a transient stimulation of Ca²⁺ outflow by this transporter, directly demonstrated by Mn²⁺ quenching experiments.

CONCLUSIONS AND IMPLICATIONS

ATP-sensitive and Ca²⁺-dependent basolateral K⁺ conductances, the basolateral Na⁺-K⁺-pump as well as Ca²⁺ transporters were involved in the action of H₂S in regulating colonic ion secretion.     

急性颈髓损伤患者低钠血症的机制及治疗方案探讨

目的探讨脊髓损伤后低钠血症的机制及治疗方法。方法 2001年2月~2007年1月共收治急性脊髓损伤患者68例（完全性损伤43例,不完全性损伤25例）。测定患者的血浆渗透压、Na＋、K＋、Ca2＋、血糖（G lu）、血尿素氮（Bun）、抗利尿激素（ADH）、血浆肾素活性、醛固酮。根据上述指标的异常将低钠血症患者分成SIADH组、CSW S组和对照组,SIADH组入选标准为：ADH浓度升高,急性期出现血钠降低,血尿素氮和血糖正常。SIADH组给予以限水为主,适当补盐的治疗方案;CSW S组入选标准为：血浆肾素活性、醛固酮、ADH浓度降低,CSW S组给予以积极补充血容量,补充丢失的钠盐。对照组：低血钠症。结果 SIADH组和CSW S组之间的治疗效果差异无统计学意义,SIADH组和CSW S组与对照组的治疗效果差异有统计学意义。结论治疗急性脊髓损伤患者低钠血症时,根据其发病机制给予不同的治疗方案,可收到明显的临床效果,减少脊髓损伤并发症的发生发展。     

Electrolyte disturbances and acute kidney injury in patients with cancer

The interrelation between kidney disease and cancer is complex and reciprocal. Among the most frequent cancer-associated kidney diseases are the electrolyte and acid-base disturbances, which occur frequently and often are associated with an ominous prognosis, and acute kidney injury. Tumor lysis syndrome is a potentially life-threatening condition that frequently occurs in patients with a high tumor burden and high cellular turnover after cytotoxic therapy (including steroids in steroid-sensitive hematologic malignancies). Electrolyte and acid-base disturbances are the consequence of neoplastic spread, anticancer treatment, or, more rarely, paraneoplastic phenomena of all types of tumors. This article reviews hyponatremia and hypernatremia, hypokalemia and hyperkalemia, hypomagnesemia, hypercalcemia and hypocalcemia, hypophosphatemia, and the most important disturbances in acid-base balance in cancer patients. Acute kidney injury (AKI) is a frequent occurrence in cancer patients and has the potential to substantially alter the outcome of patients with cancer and jeopardize their chances of receiving optimal cancer treatment and a potential cure. As in many other circumstances, the etiology of AKI in cancer patients is multifactorial. Initiation and/or continuation of dialysis in the AKI cancer patient should be based on the general clinical condition and overall life expectancy and the personal patient expectations on quality of life after eventual recovery.     

术中血液保护对颅脑肿瘤患者血电解质及凝血功能的影响

目的 观察围术期血液保护对颅脑肿瘤患者电解质及凝血功能的影响.方法 90例患者按照抽签法随机分为A、B、C 3组,A组术前静脉注射凝血酶2kU,在气管插管后静脉注射6%羟乙基淀粉130/0.4溶液15ml/kg,速率30ml/min,联合硝酸甘油控制性降压;B组凝血酶＋控制性降压;C组术前静脉注射凝血酶2kU.3组分别于麻醉前（基础值,T0）、手术开始后60min（T1）、术毕即刻（T2）和术后24h（T3）采血测定血红蛋白（Hb）、红细胞压积（Hct）、血小板（PLT）、电解质（K＋、Na＋、Cl-、Ca＋）、血浆凝血酶原时间（PT）、凝血酶时间（TT）、部分凝血活酶时间（APTT）和纤维蛋白原浓度（Fib）.结果 A组血液稀释后T1,时段Hb、Hct均明显低于T0（P＜0.05或0.01）.但在T2时段均恢复或接近于T0水平（P＞0.05）,而C组Hb、Hct、PLT在T2、T3时段均明显低于同组T0或A、B组同时段数值（P＜0.05或0.01）.3组血清K＋、Na＋、Cl-、Ca2＋在T1、T2时段与T0比较差异无统计学意义（P＞0.05）,但在T3时段血K＋均明显降低（P＜0.05）;A组PT、APTT和FjO在T1时段均明显延长或降低（P＜0.05）,而B组和C组在T2时段PT、APTT均延长（P＜0.05）,各组术后24h凝血功能指标均恢复T0水平.结论 凝血酶结合扩容性血液稀释与控制性降压用于颅脑肿瘤患者围术期血液保护对电解质及凝血功能无明显影响,且凝血酶可强化血小板和/或凝血因子的功能,利于术中止血.     

枸橼酸莫沙比利分散片配合聚乙二醇电解质散剂治疗慢性便秘的疗效观察

目的探讨枸橼酸莫沙比利分散片（新络纳）配合聚乙二醇电解质散剂（舒泰清）治疗慢性便秘的疗效。方法将临床确诊病例147例随机分成治疗组51例,采用枸橼酸莫沙比利分散片配合聚乙二醇电解质散剂治疗;对照1组46例,采用车前蕃泻颗粒治疗;对照2组50例,采用麻仁软胶囊治疗。结果治疗组有效率90．2％,对照1组有效率89．1％,两组比较差异无统计学意义（P〉0．05）,对照2组有效率74％。治疗组与对照2组比较差异有统计学意义（P〈0．05）。结论枸橼酸莫沙比利分散片配合聚乙二醇电解质散剂治疗慢性便秘的疗效与车前蕃泻颗粒疗效相当,优于麻仁软胶囊的疗效。     

莫沙必利对聚乙二醇电解质散溶液用于结肠清洁的影响

目的 评价莫沙必利是否能缓解口服聚乙二醇电解质散溶液(PEG)用于结肠清洁过程中的胃肠道不适症状,并了解它是否有助于改善PEG清洁肠道的质量.方法 前瞻性随机对照研究,甲组(2000 mL等渗PEG溶液+莫沙必利)92例、乙组(2 000 mL等渗PEG溶液)93例.主要观察恶心、呕吐、腹胀和腹痛等腹部不适症状的发生和严重程度,结肠清洁质量的分级和合格率,以及结肠镜是否插入盲肠和所用时间.结果 甲组未出现恶心、呕吐和饱胀等不适症状的比例明显高于乙组,甲组发生中或重度恶心、呕吐和饱胀等腹部不适的比例明显低于乙组,差异有显著性(P＜0.05).两组间直乙状结肠的清洁质量分级比较差异无显著性(P=0.082);但甲组右半结肠清洁质量的分级效果优于乙组,差异有显著性(P =0.036).甲组直乙状结肠或右半结肠清洁质量的合格率稍高于乙组,但差异均无显著性(P＞0.05).甲组插入盲肠的比例稍高于乙组,甲组插入盲肠所需时间稍短于乙组,但两组间比较差异均无显著性(P＞0.05).结论 加用莫沙必利有助于减少和减轻口服2000 mL等渗PEG溶液导致的消化道不适症状,可能会改善结肠清洁的质量.     

Evaluation of the accuracy of three electronic apex locators using glass tubules

AIM: To evaluate the accuracy of three different electronic apex locators (EALs) using glass tubules. METHODOLOGY: Forty-eight glass tubules with different diameters and an agar model were used to mimic root canals. A size 15 stainless steel K-file was used as the measuring electrode. The Root ZX, Propex and Neosono Ultima EZ were used to measure the tubule length with tubules dry, or filled with 0.9% NaCl, 3% H(2)O(2), 2.5% NaOCl or 17% EDTA. The distance between the real length (RL) and measured length (ML) of the tubules was recorded. The range of RL +/- 0.5 mm and RL +/- 1 mm was used to evaluate the accuracy of the EALs. Results were subject to correlation analysis and Friedman's test. RESULTS: In dry tubules, the accuracy of Root ZX was 75-91.7% for RL +/- 0.5 mm and 100% for RL +/- 1 mm, whilst the measurements of the other two EALs were all within the RL +/- 0.5 mm. No influence from the increase in tubule diameter on the accuracy of all three EALs was observed in dry tubules. In tubules filled with electrolyte, the accuracy of the Root ZX decreased as tubule diameter increased (R(d) > 0, P < 0.05). The RL-ML distance recorded by Propex was inversely related to the tubule diameter (R(d) < 0, P < 0.05). The accuracy of Propex was 75-100% for RL +/- 0.5 mm and 100% for RL +/- 0.5 mm when the tubule diameter was not more than 0.80 mm, but decreased in tubules with diameter over 0.80 mm and filled with 2.5% NaOCl or 17% EDTA. Nearly, all the measurements (except for six tubules) using Neosono Ultima EZ were within 1 mm shorter than RL despite the contents in tubules and the increase of tubule diameter. CONCLUSIONS: The accuracy of the Root ZX decreased as the tubule diameter increased when tubules were filled with electrolytes. The electrolytes in the tubules decreased the accuracy of Propex when the tubule diameter was large. The electrolytes in tubules and tubule diameter had no influence on the accuracy of Neosono Ultima EZ. The Propex and Neosono Ultima EZ were more accurate than the Root ZX under various conditions in this laboratory study.     

5％碳酸氢钠对单肺通气患者血气的影响

目的评价5％碳酸氢钠（NaHCO3）对开胸单肺通气（OLV）患者术中血气的影响。方法择期开胸手术患者60例。男44例,女16例。年龄18～65岁。体重55～80kg。随机等分3组。I组：空白对照;II组：5％NaHC0330mL;III组：5％NaHCO360mL。连续监测血压（BP）、心率（I-IR）、动脉氧饱和度（SpO2）等。3组均采用静吸复合麻醉,诱导静注芬太尼3μg/kg、丙泊酚1．5～2．0mg／kg、琥珀胆碱1．5mg／kg,维持吸入1．0％-2．0％异氟烷,持续输注瑞芬太尼0．1～0．2μg／（kg·min）和间断静注维库溴铵0．02～0．03mg／kg。OLV后应用5％NaHCO3（Ⅱ组：1mL/min;Ⅲ组：2mL/min）,分别在麻醉前（T0）、麻醉诱导后双肺通气时（T1）、单肺通气30分钟时（T2）、手术完毕前双肺通气时（L）采外周动脉血1mL进行血气分析。结果麻醉后组内比较：SpO2、动脉氧分压（PaO2）、血氧饱和度（SaO2）和CL^-3组麻醉后均有升高,与T0比较（P〈0．05或P〈0．01）;pH值、碱剩余（BE）和K‘3组在麻醉后均有下降,与T0比较（P〈0．05或P〈0．01）。麻醉后同时间段组间比较：SaO2在T2时间段Ⅲ组比I组和Ⅱ组高（P〈0．05）;BE在T2时间段、T3时间段Ⅲ组比I组高（P〈0．05和P〈0．01）。Ⅲ组患者苏醒最快,与I组比较（P〈0．05）。结论Ⅲ组患者呼吸系统相对平稳,保持较高的SaO2,pH值和BE值下降幅度减小,苏醒迅速,有高氯代酸倾向,但是不会影响CO2的排除。     

芪苈强心胶囊治疗慢性充血性心力衰竭效果评价

目的：观察芪苈强心胶囊治疗慢性充血性心力衰竭（CHF）的临床疗效。方法：将64例CHF患者采用随机数字表随机分为治疗组33例和对照组31例,两组基线水平无差异,两组均应用洋地黄、利尿剂、ACEI等常规治疗,治疗组加服芪苈强心胶囊。比较两组患者治疗前后出汗改善情况、心功能好转率、6分钟步行距离、血清离子变化及用药期间的不良反应。结果：治疗1、2周后治疗组患者出汗缓解率高于对照组（P<0.05）。治疗1周后两组患者心功能和6分钟步行距离均较治疗前提高,但组间比较差异无显著性（P>0.05）,2周后治疗组优于对照组（P<0.05）。治疗1周后两组患者血清Na+水平均较治疗前降低,但组间比较差异无显著性（P>0.05）;2周后治疗组血清Na+水平高于对照组（P<0.05）。治疗1、2周后两组血清K+水平比较差异无显著性（P>0.05）。治疗组和对照组患者未出现任何不良反应,无停用芪苈强心胶囊者。结论：芪苈强心胶囊对患者止汗作用明显,短期内即可见效;有一定的强心作用,但起效相对慢;有一定的保钠作用,对血钾影响不大;耐受性好。