Capillary Electrophoresis-Atmospheric Pressure Chemical Ionization-Mass Spectrometry Using an Orthogonal Interface: Set-Up and System Parameters

The feasibility of atmospheric pressure chemical ionization (APCI) as an alternative ionization technique for capillary electrophoresis-mass spectrometry (CE-MS) was investigated using a grounded sheath-flow CE-MS sprayer and an orthogonal APCI source. Infusion experiments indicated that highest analyte signals were achieved when the sprayer tip was in close vicinity of the vaporizer entrance. The APCI-MS set-up enabled detection of basic, neutral, and acidic compounds, whereas apolar and ionic compounds could not be detected. In the positive ion mode, analytes could be detected in the entire transfer voltage range (0–5 kV), whereas highest signal intensities were observed when the corona discharge current was between 1000 and 2000 nA. In the negative ion mode, the transfer voltage typically was 500 V and the optimum corona discharge current was 6000 nA. Analyte signals were raised with increasing nebulizing gas pressure, but the pressure was limited to 25 psi to avoid siphoning and current drops. Signal intensities appeared to be optimal and constant over a wide range of sheath liquid flow rate (5–25 μL/min) and vaporizer temperature (200–350°C). APCI-MS signals were unaffected by the composition of the background electrolyte (BGE), even when it contained sodium phosphate and sodium dodecyl sulfate (SDS). Consequently, BGE composition, sheath-liquid flow rate, and vaporizer temperature can be optimized with respect to the CE separation without affecting the APCI-MS response. The analysis of a mixture of basic compounds and a steroid using volatile and nonvolatile BGEs further demonstrates the feasibility of CE-APCI-MS. Detection limits (S/N = 3) were 1.6–10 μM injected concentrations

Cardiovascular drug use and differences in the incidence of cardiovascular mortality in elderly Serbian men

OBJECTIVE: To assess whether the difference in risk of cardiovascular mortality between urban and rural areas of Serbia could be explained by differences in the use of cardiovascular medication. METHODS: The Serbian cohorts of the Seven Countries Study, Velika Krsna (VK), Zrenjanin (ZR) and Belgrade (BG), were enrolled in 1962-1964 and were followed up for 25 years. The survivors of these cohorts were re-examined in 1987, 1988 and 1989, respectively. This second examination of elderly men aged 65 to 84 years included a questionnaire about current use of cardiovascular medication, risk factors and diseases and a physical examination. All subjects were followed until death or the predefined censor date (10 years after baseline). The Cox proportional hazards model was used to calculate the risk of cardiovascular mortality in the rural cohorts compared to the urban cohort and to adjust for confounding. MAIN OUTCOME MEASURE: Cardiovascular death. RESULTS: A total of 227 men from VK, 184 men from ZR and 287 men from BG were followed for a mean duration of 7.4 years and was complete for all subjects. After exclusion of 13 subjects with missing medication data, the incidences of cardiovascular mortality in VK, ZR, and BG were 60, 74, and 26 per 1,000 person-years, respectively. The prevalence of cardiovascular medication use was 38% in VK, 52% in ZR, and 59% in BG. The greatest difference in use of specific medication was observed for betablockers (0% in VK and ZR, 13% in BG). After adjustment for cardiovascular risk factors, diseases and age, the relative risks (RRs) of cardiovascular mortality were 2.12 [95% CI: 1.44-3.12], and 2.27 [95% CI: 1.56-3.30] in VK, and ZR compared to BG. Additional adjustment for the use of cardiovascular medication increased these RRs to 2.40 [95% CI: 1.61-3.60] and 2.55 [95% CI: 1.72-3.78], respectively. CONCLUSION: The variation in cardiovascular medication use could not explain the excess risk of mortality in the rural Serbian cohorts compared to urban Belgrade

Cardiovascular drug use and differences in the incidence of cardiovascular mortality in elderly Serbian men

OBJECTIVE: To assess whether the difference in risk of cardiovascular mortality between urban and rural areas of Serbia could be explained by differences in the use of cardiovascular medication. METHODS: The Serbian cohorts of the Seven Countries Study, Velika Krsna (VK), Zrenjanin (ZR) and Belgrade (BG), were enrolled in 1962-1964 and were followed up for 25 years. The survivors of these cohorts were re-examined in 1987, 1988 and 1989, respectively. This second examination of elderly men aged 65 to 84 years included a questionnaire about current use of cardiovascular medication, risk factors and diseases and a physical examination. All subjects were followed until death or the predefined censor date (10 years after baseline). The Cox proportional hazards model was used to calculate the risk of cardiovascular mortality in the rural cohorts compared to the urban cohort and to adjust for confounding. MAIN OUTCOME MEASURE: Cardiovascular death. RESULTS: A total of 227 men from VK, 184 men from ZR and 287 men from BG were followed for a mean duration of 7.4 years and was complete for all subjects. After exclusion of 13 subjects with missing medication data, the incidences of cardiovascular mortality in VK, ZR, and BG were 60, 74, and 26 per 1,000 person-years, respectively. The prevalence of cardiovascular medication use was 38% in VK, 52% in ZR, and 59% in BG. The greatest difference in use of specific medication was observed for betablockers (0% in VK and ZR, 13% in BG). After adjustment for cardiovascular risk factors, diseases and age, the relative risks (RRs) of cardiovascular mortality were 2.12 [95% CI: 1.44-3.12], and 2.27 [95% CI: 1.56-3.30] in VK, and ZR compared to BG. Additional adjustment for the use of cardiovascular medication increased these RRs to 2.40 [95% CI: 1.61-3.60] and 2.55 [95% CI: 1.72-3.78], respectively. CONCLUSION: The variation in cardiovascular medication use could not explain the excess risk of mortality in the rural Serbian cohorts compared to urban Belgrade