Serum endocan levels in patients with cardiac syndrome X.

BACKGROUND: Endocan is a recently introduced marker of endothelial dysfunction and is also associated with inflammation and atherosclerosis. To date, the relationship between cardiac syndrome X (CSX) and endocan has not been studied. The objective of this study was to compare the serum endocan levels of patients with CSX with those of control subjects. PATIENTS AND METHODS: In this study, 50 patients were included in the CSX group and 28 patients in the control group. Patients with pathological conditions that could potentially influence endothelial functions were excluded. Endocan serum concentrations were measured using an enzyme-linked immunosorbent assay. RESULTS: The mean endocan level of the CSX group was significantly higher than that of the control group (3051.3 ± 1900.5 ng/l vs. 2088.1 ± 522.2 ng/l; p = 0.002). There was no difference between the two groups in terms of age, gender, hypertension, diabetes mellitus, dyslipidemia, and smoking status. In receiver operating characteristic (ROC) curve analysis, endocan levels greater than 2072 ng/l had a 72% sensitivity and 54% specificity (p = 0.002) for accurately predicting a diagnosis of CSX. CONCLUSION: The results of this study suggest that patients with CSX have higher endocan levels. Therefore, endocan may be valuable in helping uncover the underlying pathogenesis of CSX.

Liquid-phase chemical sensing using lateral mode resonant cantilevers.

Liquid-phase operation of resonant cantilevers vibrating in an out-of-plane flexural mode has to date been limited by the considerable fluid damping and the resulting low quality factors (Q factors). To reduce fluid damping in liquids and to improve the detection limit for liquid-phase sensing applications, resonant cantilever transducers vibrating in their in-plane rather than their out-of-plane flexural resonant mode have been fabricated and shown to have Q factors up to 67 in water (up to 4300 in air). In the present work, resonant cantilevers, thermally excited in an in-plane flexural mode, are investigated and applied as sensors for volatile organic compounds in water. The cantilevers are fabricated using a complementary metal oxide semiconductor (CMOS) compatible fabrication process based on bulk micromachining. The devices were coated with chemically sensitive polymers allowing for analyte sorption into the polymer. Poly(isobutylene) (PIB) and poly(ethylene-co-propylene) (EPCO) were investigated as sensitive layers with seven different analytes screened with PIB and 12 analytes tested with EPCO. Analyte concentrations in the range of 1-100 ppm have been measured in the present experiments, and detection limits in the parts per billion concentration range have been estimated for the polymer-coated cantilevers exposed to volatile organics in water. These results demonstrate significantly improved sensing properties in liquids and indicate the potential of cantilever-type mass-sensitive chemical sensors operating in their in-plane rather than out-of-plane flexural modes.