PubMed · 4664502
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R E Bernstein. 1972-12-02. Some comments on potassium.. https://pubmed.ncbi.nlm.nih.gov/4664502/
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An analytical procedure was developed for the fast screening of 16 diuretics (acetazolamide, althiazide, amiloride, bendroflumethiazide, bumetanide, canrenoic acid, chlorthalidone, chlorthiazide, clopamide, ethacrynic acid, furosemide, hydrochlorthiazide, hydroflumethiazide, indapamide, triamterene, trichlormethiazide) and a masking agent (probenecid) in human urine. The whole method involves three analytical steps, including (1) liquid/liquid extraction of the analytes from the matrix, (2) their reaction with methyl iodide at 70 degrees C for 2 h to form methyl derivatives, (3) analysis of the resulting mixture by fast gas chromatography/electron impact mass spectrometry (fast GC/EI-MS). The analytical method was validated by determining selectivity, linearity, accuracy, intra and inter assay precision, extraction efficiencies and signal to noise ratio (S/N) at the lowest calibration level (LCL) for all candidate analytes. The analytical performances of three extraction procedures and five combination of derivatization parameters were compared in order to probe the conditions for speeding up the sample preparation step. Limits of detection (LOD) were evaluated in both EI-MS and ECNI-MS (electron capture negative ionization mass spectrometry) modes, indicating better sensitivity for most of the analytes using the latter ionization technique. The use of short columns and high carrier gas velocity in fast GC/MS produced efficient separation of the analytes in less than 4 min, resulting in a drastic reduction of the analysis time, while a resolution comparable to that obtained from classic GC conditions is maintained. Fast quadrupole MS electronics allows high scan rates and effective data acquisition both in scan and selected ion monitoring modes.
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BACKGROUND: Ménière's disease is a disorder characterised by hearing loss, tinnitus and disabling vertigo. Diuretics are used to try and reduce the severity and frequency of episodes but there is little evidence behind this treatment. OBJECTIVES: To assess the effect of diuretic treatment in patients with Ménière's disease. SEARCH STRATEGY: We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2005), MEDLINE (1966 to 2005), EMBASE (1974 to 2005), CINAHL and the metaRegister of Controlled Trials (mRCT) (up to 2005). SELECTION CRITERIA: Randomised controlled trials of diuretic versus placebo in Ménière's patients. DATA COLLECTION AND ANALYSIS: One author identified studies which loosely met the inclusion criteria and full texts were retrieved. Two authors independently applied the inclusion criteria. Seven studies were excluded from the review due to inappropriate study design or absence of randomisation. MAIN RESULTS: There were no trials of high enough quality to meet the standard set for this review. AUTHORS' CONCLUSIONS: There is insufficient good evidence of the effect of diuretics on vertigo, hearing loss, tinnitus or aural fullness in clearly defined Ménière's disease.