A selective, sensitive and precise assay based on solid phase extraction and liquid chromatography–tandem mass spectrometry(LC–MS/MS) was developed for the simultaneous determination of amiloride(AMI) and hydrochlor...A selective, sensitive and precise assay based on solid phase extraction and liquid chromatography–tandem mass spectrometry(LC–MS/MS) was developed for the simultaneous determination of amiloride(AMI) and hydrochlorothiazide(HCTZ) in human plasma. Sample clean-up with 250 μL of plasma was done on Phenomenex Strata^(?)-X extraction cartridges using their labeled internal standards(AMI-15 N3 and HCTZ-13 C,d2). Chromatography was performed on Hypersil Gold C18(50 mm×3.0 mm, 5 μm) column using acetonitrile with 4.0 m M ammonium formate(p H 4.0, adjusted with 0.1% formic acid)(80:20, v/v) as the mobile phase. Detection was carried out on a triple quadrupole API 5500 mass spectrometer utilizing an electrospray ionization interface and operating in the positive ionization mode for AMI and negative ionization mode for HCTZ. Multiple reaction monitoring was used following the transitions at m/z 230.6/116.0, m/z233.6/116.0, m/z 296.0/204.9 and m/z 299.0/205.9 for AMI, AMI-15 N3, HCTZ and HCTZ-13 C,d2,respectively. Calibration curves were linear(r2≥0.9997) over the concentration range of 0.050–50.0 and0.50–500 ng/m L for AMI and HCTZ, respectively, with acceptable accuracy and precision. The signal-to-noise ratio at the limit of quantitation was ≥14 for both the analytes. The mean recovery of AMI and HCTZ from plasma was 89.0% and 98.7%, respectively. The IS-normalized matrix factors determined for matrix effect ranged from 0.971 to 1.024 for both the analytes. The validated LC–MS/MS method was successfully applied to a bioequivalence study using 5 mg AMI and 50 mg HCTZ fixed dose tablet formulation in 18 healthy Indian volunteers with good reproducibility.展开更多
Esophageal adenocarcinoma is increasing in the US and Western countries and frequent gastresophageal reflux or gastresophageal reflux disease carrying gastric acid and bile acid could contribute to esophageal adenocar...Esophageal adenocarcinoma is increasing in the US and Western countries and frequent gastresophageal reflux or gastresophageal reflux disease carrying gastric acid and bile acid could contribute to esophageal adenocarcinogenesis. This study was designed to detect the expression of gastric acid-inducing gene Na＋/H＋ exchanger-1 （NHE-1） ex vivo and then to explore targeting of NHE-1 expression or activity to control esophageal cancer cell viability in vitro and in nude mouse xenografts. The data showed that NHE-1 was highly expressed in esophageal adenocarcinoma tissues （66 of 101 cases [65.3%｜, but not in normal esophageal squamous cell epithelium （1 of 26 cases [3.8~0]）. Knockdown of NHE-1 expression using NHE-1 shRNA or inhibition of NHE-1 activity using the NHE-1 inhibitor amiloride suppressed viability and induced apoptosis in esophageal cancer cells. Molecularly, amiloride inhibited expression of cyclooxygenase-2 and matrix metallopeptidase-9 but not NHE-1 mRNA in esophageal cancer cells. A combination of amiloride and guggulsterone （a natural bile acid receptor inhibitor） showed more than additive effects in suppressing esophageal cancer cell growth in vitro and in nude mouse xenografts. This study suggests that inhibition of NHE-1 expression or activity or combination of amiloride and guggulsterone could be useful in control of esophageal adenocarcinoma.展开更多
In the retina, pH fluctuations may play an important role in adapting retinal responses to different light intensities and are involved in the fine tuning of visual perception. Acidosis occurs in the subretinal space ...In the retina, pH fluctuations may play an important role in adapting retinal responses to different light intensities and are involved in the fine tuning of visual perception. Acidosis occurs in the subretinal space （SRS） under pathological conditions such as age-related macular degeneration （AMD）. Although it is well known that many transporters in the retinal pigment epithelium （RPE） cells can maintain pH homeostasis efficiently, other receptors in RPE may also be involved in sensing acidosis, such as acid-sensing ion channels （ASICs）. In this study, we investigated whether ASICla was ex- pressed in the RPE cells and whether it was involved in the function of these cells. Real-time RT-PCR and Western blotting were used to analyze the ASICla expression in ARPE-19 cells during oxidative stress induced by hydrogen peroxide （H202）. Furthermore, inhibition or over-expression of ASICla in RPE cells was obtained using inhibitors （amiloride and PCTxl） or by the transfection of cDNA encod- ing hASICla. Cell viability was determined by using the MTT assay. The real-time RT-PCR and West- ern blotting results showed that both the mRNA and protein of ASICla were expressed in RPE cells. In- hibition of ASICs by amiloride in normal RPE cells resulted in cell death, indicating that ASICs play an important physiological role in RPE cells. Furthermore, over-expression of ASICla in RPE cells pro- longed cell survival under oxidative stress induced by H2O2. In conclusion, ASICla is functionally expressed in RPE cells and may play an important role in the physiological function of RPE cells by pro-tecting them from oxidative stress.展开更多
Drugs Used Uropoiem System Diseases 泌尿系统用药Amiloride 阿米洛利Bumetanide 丁尿胺依他尼酸（利尿酸）Etacrynic Acid 依他尼酸（利尿酸） Furosemide 呋塞米（呋喃苯胺酸，速尿） H ydrochlorothiazide 氢氯噻嗪（双氢克...Drugs Used Uropoiem System Diseases 泌尿系统用药Amiloride 阿米洛利Bumetanide 丁尿胺依他尼酸（利尿酸）Etacrynic Acid 依他尼酸（利尿酸） Furosemide 呋塞米（呋喃苯胺酸，速尿） H ydrochlorothiazide 氢氯噻嗪（双氢克尿塞）展开更多
Diuretics are drugs widely used in treatment of heart failure and hypertension and as doping agents in sports. Wrong prescription and excessive abuse can lead to negative side effects. Despite the effectiveness of met...Diuretics are drugs widely used in treatment of heart failure and hypertension and as doping agents in sports. Wrong prescription and excessive abuse can lead to negative side effects. Despite the effectiveness of methods usually used for the determination of diuretics (gas or liquid chromatography, capillary electrophoresis), they do not always provide necessary sensitivity. Moreover, sample preparation increases time of analysis. A rapid and sensitive luminescent method for determination of 5 diuretics (amiloride, bendroflumethiazide, bumetanide, furosemide, triamterene) in aqueous solutions and amiloride and triamterene in human urine is described. Intrinsic luminescent properties of protolytic forms of diuretics were studied in order to provide highly sensitive analysis. Investigation of interfering influence of diuretics was carried out to provide selective determination of triamterene, bumetanide and furosemide in aqueous mixtures of diuretics. Influence of urine at luminescent properties of diuretics was studied. The possibility of determination of triamterene and amiloride in human urine as individual substances and in mixture was proved. Simple and rapid technique for their determination in human urine was elaborated. The techniques elaborated for determination of triamterene in presence of other diuretics and furosemide in presence of commensurate amount of bumetanide allow enhancing specifity of analysis. Sufficient selectivity and sensitivity were reached in determination of amiloride and triamterene in human urine. The reduction of time of analysis due to avoiding sample preparation merits the techniques proposed.展开更多
文摘A selective, sensitive and precise assay based on solid phase extraction and liquid chromatography–tandem mass spectrometry(LC–MS/MS) was developed for the simultaneous determination of amiloride(AMI) and hydrochlorothiazide(HCTZ) in human plasma. Sample clean-up with 250 μL of plasma was done on Phenomenex Strata^(?)-X extraction cartridges using their labeled internal standards(AMI-15 N3 and HCTZ-13 C,d2). Chromatography was performed on Hypersil Gold C18(50 mm×3.0 mm, 5 μm) column using acetonitrile with 4.0 m M ammonium formate(p H 4.0, adjusted with 0.1% formic acid)(80:20, v/v) as the mobile phase. Detection was carried out on a triple quadrupole API 5500 mass spectrometer utilizing an electrospray ionization interface and operating in the positive ionization mode for AMI and negative ionization mode for HCTZ. Multiple reaction monitoring was used following the transitions at m/z 230.6/116.0, m/z233.6/116.0, m/z 296.0/204.9 and m/z 299.0/205.9 for AMI, AMI-15 N3, HCTZ and HCTZ-13 C,d2,respectively. Calibration curves were linear(r2≥0.9997) over the concentration range of 0.050–50.0 and0.50–500 ng/m L for AMI and HCTZ, respectively, with acceptable accuracy and precision. The signal-to-noise ratio at the limit of quantitation was ≥14 for both the analytes. The mean recovery of AMI and HCTZ from plasma was 89.0% and 98.7%, respectively. The IS-normalized matrix factors determined for matrix effect ranged from 0.971 to 1.024 for both the analytes. The validated LC–MS/MS method was successfully applied to a bioequivalence study using 5 mg AMI and 50 mg HCTZ fixed dose tablet formulation in 18 healthy Indian volunteers with good reproducibility.
文摘Esophageal adenocarcinoma is increasing in the US and Western countries and frequent gastresophageal reflux or gastresophageal reflux disease carrying gastric acid and bile acid could contribute to esophageal adenocarcinogenesis. This study was designed to detect the expression of gastric acid-inducing gene Na＋/H＋ exchanger-1 （NHE-1） ex vivo and then to explore targeting of NHE-1 expression or activity to control esophageal cancer cell viability in vitro and in nude mouse xenografts. The data showed that NHE-1 was highly expressed in esophageal adenocarcinoma tissues （66 of 101 cases [65.3%｜, but not in normal esophageal squamous cell epithelium （1 of 26 cases [3.8~0]）. Knockdown of NHE-1 expression using NHE-1 shRNA or inhibition of NHE-1 activity using the NHE-1 inhibitor amiloride suppressed viability and induced apoptosis in esophageal cancer cells. Molecularly, amiloride inhibited expression of cyclooxygenase-2 and matrix metallopeptidase-9 but not NHE-1 mRNA in esophageal cancer cells. A combination of amiloride and guggulsterone （a natural bile acid receptor inhibitor） showed more than additive effects in suppressing esophageal cancer cell growth in vitro and in nude mouse xenografts. This study suggests that inhibition of NHE-1 expression or activity or combination of amiloride and guggulsterone could be useful in control of esophageal adenocarcinoma.
基金supported by the National Natural Science Foundation of China (No. 81200681)
文摘In the retina, pH fluctuations may play an important role in adapting retinal responses to different light intensities and are involved in the fine tuning of visual perception. Acidosis occurs in the subretinal space （SRS） under pathological conditions such as age-related macular degeneration （AMD）. Although it is well known that many transporters in the retinal pigment epithelium （RPE） cells can maintain pH homeostasis efficiently, other receptors in RPE may also be involved in sensing acidosis, such as acid-sensing ion channels （ASICs）. In this study, we investigated whether ASICla was ex- pressed in the RPE cells and whether it was involved in the function of these cells. Real-time RT-PCR and Western blotting were used to analyze the ASICla expression in ARPE-19 cells during oxidative stress induced by hydrogen peroxide （H202）. Furthermore, inhibition or over-expression of ASICla in RPE cells was obtained using inhibitors （amiloride and PCTxl） or by the transfection of cDNA encod- ing hASICla. Cell viability was determined by using the MTT assay. The real-time RT-PCR and West- ern blotting results showed that both the mRNA and protein of ASICla were expressed in RPE cells. In- hibition of ASICs by amiloride in normal RPE cells resulted in cell death, indicating that ASICs play an important physiological role in RPE cells. Furthermore, over-expression of ASICla in RPE cells pro- longed cell survival under oxidative stress induced by H2O2. In conclusion, ASICla is functionally expressed in RPE cells and may play an important role in the physiological function of RPE cells by pro-tecting them from oxidative stress.
文摘Drugs Used Uropoiem System Diseases 泌尿系统用药Amiloride 阿米洛利Bumetanide 丁尿胺依他尼酸（利尿酸）Etacrynic Acid 依他尼酸（利尿酸） Furosemide 呋塞米（呋喃苯胺酸，速尿） H ydrochlorothiazide 氢氯噻嗪（双氢克尿塞）
文摘Diuretics are drugs widely used in treatment of heart failure and hypertension and as doping agents in sports. Wrong prescription and excessive abuse can lead to negative side effects. Despite the effectiveness of methods usually used for the determination of diuretics (gas or liquid chromatography, capillary electrophoresis), they do not always provide necessary sensitivity. Moreover, sample preparation increases time of analysis. A rapid and sensitive luminescent method for determination of 5 diuretics (amiloride, bendroflumethiazide, bumetanide, furosemide, triamterene) in aqueous solutions and amiloride and triamterene in human urine is described. Intrinsic luminescent properties of protolytic forms of diuretics were studied in order to provide highly sensitive analysis. Investigation of interfering influence of diuretics was carried out to provide selective determination of triamterene, bumetanide and furosemide in aqueous mixtures of diuretics. Influence of urine at luminescent properties of diuretics was studied. The possibility of determination of triamterene and amiloride in human urine as individual substances and in mixture was proved. Simple and rapid technique for their determination in human urine was elaborated. The techniques elaborated for determination of triamterene in presence of other diuretics and furosemide in presence of commensurate amount of bumetanide allow enhancing specifity of analysis. Sufficient selectivity and sensitivity were reached in determination of amiloride and triamterene in human urine. The reduction of time of analysis due to avoiding sample preparation merits the techniques proposed.
