METHODS: Serum and urine samples were collected from healthy human subjects. The experiment was divided into two parts, part one to evaluate 2,2,2,2-tetradeutero-4,4-dimethyl-4-silapentanoic acid (TSP) and 4,4-dimethyl-4-silapentane-1-ammonium trifluoroacetate (DSA) as the optimal internal standard for the serum and urine samples. The second part investigated the effects of preservatives in the serum and urine samples on extended storage.
RESULTS: Overall, TSP and DSA are suitable to be used as an internal standard in human urine samples. However, DSA is a superior internal standard in serum samples for NMR analysis. For the effect of preservative, the results indicated that human serum and urine samples could be stored without addition of preservative in -80 °C, as no changes in NMR fingerprinting have been observed during storage in the absence or presence of the preservative.
CONCLUSIONS: The findings suggest the use of DSA and TSP as an internal standard in serum and urine samples, respectively. Storage of serum and urine samples without any addition of preservative for an extended period has no effect on the metabolites changes. By having a standardised method, it will offer a considerable saving in both operator and spectrometer time and most importantly produce reproducible and reliable data.
METHODS: Serum and urine samples were collected from healthy human subjects. The experiment was divided into two parts, part one to evaluate 2,2,2,2-tetradeutero-4,4-dimethyl-4-silapentanoic acid (TSP) and 4,4-dimethyl-4-silapentane-1-ammonium trifluoroacetate (DSA) as the optimal internal standard for the serum and urine samples. The second part investigated the effects of preservatives in the serum and urine samples on extended storage.
RESULTS: Overall, TSP and DSA are suitable to be used as an internal standard in human urine samples. However, DSA is a superior internal standard in serum samples for NMR analysis. For the effect of preservative, the results indicated that human serum and urine samples could be stored without addition of preservative in -80 °C, as no changes in NMR fingerprinting have been observed during storage in the absence or presence of the preservative.
CONCLUSIONS: The findings suggest the use of DSA and TSP as an internal standard in serum and urine samples, respectively. Storage of serum and urine samples without any addition of preservative for an extended period has no effect on the metabolites changes. By having a standardised method, it will offer a considerable saving in both operator and spectrometer time and most importantly produce reproducible and reliable data.
METHODS: A total 621 patients with estimated glomerular filtration rate (eGFR) of 15-59ml/min/1.73m(2) (CKD stage 3 & 4) were selected and followed up for 10 years or until ESRD or death, whichever occurred first. Subjects who did not meet inclusion criteria were excluded (n=1474).
RESULTS: Annual cumulative decline in eGFR was 3.01±0.40 ml/min/1.73m(2) . Overall disease progression was observed in 60% patients while 18% died. Among patients with CKD stage 3, 21% progressed to stage 4, 10% to stage 5ND (non-dialysis) and 31% to RRT while mortality was observed in 16% patients. On the other hand, 8% patients with CKD stage 4 progressed to stage 5ND, 31% to RRT and mortality was observed in 24% cases. Patients with CVD, higher systolic blood pressure, elevated phosphate levels, heavy proteinuria, microscopic hematuria and use of diuretics were more likely to develop ESRD. Advancing age, low eGFR, low systolic blood pressure, low hemoglobin and baseline diabetes were found to be significant predictors of mortality while being female reduced risk of mortality.
CONCLUSION: Our data suggest that, in this CKD cohort, patients were more likely to develop ESRD than death. Prime importance should be given to mild forms of CKD to retard and even reverse CKD progression.
SETTING: Five medical and cardiology wards of a tertiary care center in Malaysia.
SUBJECTS: Five hundred cardiac inpatients, who received ACEIs concomitantly with other interacting drugs.
METHOD: This was a prospective cohort study of 500 patients with cardiovascular diseases admitted to Penang Hospital between January to August 2006, who received ACEIs concomitantly with other interacting drugs. ACEI-drug interactions of clinical significance were identified using available drug information resources. Drug Interaction Probability Scale (DIPS) was used to assess the causality of association between ACEI-drug interactions and the adverse outcome (hyperkalemia).
MAIN OUTCOME MEASURE: Hyperkalemia as an adverse clinical outcome of the interaction was identified from laboratory investigations.
RESULTS: Of the 489 patients included in the analysis, 48 (9.8%) had hyperkalemia thought to be associated with ACEI-drug interactions. Univariate analysis using binary logistic regression revealed that advanced age (60 years or more), and taking more than 15 medications were independent risk factors significantly associated with hyperkalemia. However, current and previous smoking history appeared to be a protective factor. Risk factors identified as predictors of hyperkalemia secondary to ACEI-drug interactions by multi-logistic regression were: advanced age (adjusted OR 2.3, CI 1.07-5.01); renal disease (adjusted OR 4.7, CI 2.37-9.39); hepatic disease (adjusted OR 5.2, CI 1.08-25.03); taking 15-20 medications (adjusted OR 4.4, CI 2.08-9.19); and taking 21-26 medications (adjusted OR 9.0, CI 1.64-49.74).
CONCLUSION: Cardiac patients receiving ACEIs concomitantly with potentially interacting drugs are at high risk of experiencing hyperkalemia. Old age, renal disease, hepatic disease, and receiving large number of medications are factors that may significantly increase their vulnerability towards this adverse outcome; thus, frequent monitoring is advocated.