Coordination-Induced Multivalent Self-Assembling Catalysts for Spectral Sensing Zn2+ with High Selectivity and Sensitivity.

The introduction of signal amplification to molecular spectral sensing systems is an intriguing topic in supramolecular analytical chemistry. In this study, click chemistry was used to generate a triazole moiety to bridge with a long hydrophobic alkyl chain (Cn) and another short alkyl chain (Cm) bearing a 1,4,7-triazacyclonane (TACN) group for efficiently generating a self-assembling multivalent catalyst, Cn-triazole-Cm-TACN·Zn2+ (n and m represent the carbon numbers of both alkyl chains, respectively; n = 16, 18, and 20; m = 2 and 6), to catalyze the hydrolysis of 2-hydroxypropyl-4-nitrophenyl phosphate (HPNPP) when Zn2+ was added. The triazole moiety introduced adjacent to the TACN group plays an important role in improving the selectivity of Zn2+ because the triazole moiety can participate in the coordination interaction between the Zn2+ and neighboring TACN group. The supplementary triazole complexing increases the space requirement for coordinated metal ions. This catalytic sensing system also shows high sensitivity, with a favorable limit of detection down to 350 nM, even if only UV-vis absorption spectra rather than more sensitive fluorescence techniques were used for signaling, and can be used to determine the concentration of Zn2+ in tap water, which demonstrates the practical application feasibility.

Minimalistic Artificial Catalysts with Esterase-Like Activity from Multivalent Nanofibers Formed by the Self-Assembly of Dipeptides.

Imitating and incorporating the multiple key structural features observed in natural enzymes into a minimalistic molecule to develop an artificial catalyst with outstanding catalytic efficiency is an attractive topic for chemists. Herein, we designed and synthesized one class of minimalistic dipeptide molecules containing a terminal -SH group and a terminal His-Phe dipeptide head linked by a hydrophobic alkyl chain with different lengths, marked as HS-C n+1-His-Phe (n = 4, 7, 11, 15, and 17; n + 1 represents the carbon atom number of the alkyl chain). The His (-imidazole), Phe (-CO2 -) moieties, the terminal -SH group, and a long hydrophobic alkyl chain were found to have important contributions to achieve high binding ability leading to outstanding absolute catalytic efficiency (k cat/K M) toward the hydrolysis reactions of carboxylic ester substrates.

Relationship between obstructive sleep apnea and coronary microcirculatory function among patients with cardiac syndrome X.

OBJECTIVES: Obstructive sleep apnea (OSA) is an emerging risk factor for cardiovascular disease. Microcirculatory dysfunction has been proposed as a potential mechanism in the pathogenesis of cardiovascular disease in OSA. This study aims to investigate the relationship between OSA and coronary microcirculatory function. PATIENTS AND METHODS: One thousand and thirty-eight patients (598 female, mean age 60±9 years) with angiographically normal coronary arteries were divided into three groups with non-OSA of apnea-hypopnea index (AHI) less than 5 (n=403), mild-to-moderate OSA of AHI 5-30 (n=386), and severe OSA of AHI more than 30 (n=249). RESULTS: The prevalence of OSA was very high in patients with syndrome X (635/1038). Patients with higher AHI values had a lower coronary flow reserve, were more likely to have a higher total cholesterol, low-density lipoprotein cholesterol, and high sensitive C-reactive protein, and were more likely to be obese. Compared with the non-OSA group, the multivariable-adjusted odds ratio of coronary microcirculatory function for an AHI of 5-30 events/h was 1.93, 95% confidence interval 1.66-3.47, P=0.038, and for an AHI of more than 30 events/h was 2.18, 95% confidence interval 1.62-4.23, P=0.024, in model 1; and coronary microcirculatory function for an AHI of 5-30 events/h and more than 30 events/h odds ratio 1.31, 95% confidence interval 1.06-2.88, P=0.043, versus odds ratio 2.08, 95% confidence interval 1.03-2.16, P=0.036, in model 2. CONCLUSION: As compared with having no sleep apnea, categories with higher AHI were associated with increased odds of lower coronary flow reserve. The data suggested a close relationship between OSA and coronary microcirculatory function in atherosclerosis.

Myeloperoxidase and risk of recurrence of atrial fibrillation after catheter ablation.

BACKGROUND: Myeloperoxidase (MPO) has been associated with the development of atrial fibrillation (AF), but its impact on the recurrence of AF after catheter ablation has not been explored. This study investigated the effect of plasma MPO on recurrence after catheter ablation of paroxysmal AF. METHODS AND RESULTS: Two hundred eighty-eight consecutive patients with paroxysmal AF and who underwent circumferential pulmonary vein isolation were prospectively enrolled. After a mean ± SD follow-up of 516 ± 204 (91-910) days, the recurrence rates were 16.9%, 25.7%, 29.7%, and 38.0% from the lowest MPO quartile to the highest MPO quartile, respectively (P = 0.023). After adjustment for age, sex, left atrial diameter, high-sensitivity C-reactive protein, and pulmonary vein isolation, there was an increased risk of recurrence in the subjects with the highest MPO quartile compared with those with the lowest quartile (hazard ratio, 3.18; 95% confidence interval, 2.12-5.23; P = 0.024). As a continuous variable, MPO was also an independent predictor of recurrence (hazard ratio, 2.12; 95% confidence interval, 1.71-3.27; P = 0.032). CONCLUSIONS: Patients with high MPO levels were at an increased risk of AF recurrence after catheter ablation.

Correlation between plasma lipoprotein-associated phospholipase A2 and peripheral arterial disease.

Lipoprotein-associated phospholipase A2 (Lp-PLA2) is a recently identified and potentially useful plasma biomarker for cardiovascular diseases. However, its role in peripheral arterial disease (PAD) remains unclear. The objective of this study was to assess the independent association of Lp-PLA2 and other inflammatory markers with the reduced ankle-brachial blood pressure index (ABI), a marker of PAD. We performed a cross-sectional study in 982 individuals aged ≥40 years who were recruited from the First Affiliated Hospital of Zhengzhou University. PAD was defined as an ABI <0.9 in at least one leg. The individuals were further divided into two groups, 145 with PAD and 837 without PAD. Following adjustment for traditional cardiovascular risk factors, the odds ratios of PAD when comparing the highest to the lowest quartiles were 3.24 (95% CI, 1.68-3.94) for Lp-PLA2, 2.14 (95% CI, 1.07-3.11) for homocysteine, 1.93 (95% CI, 1.02-4.01) for fibrinogen, 2.26 (95% CI, 1.32-5.74) for apolipoprotein B and 1.3 (95% CI, 0.75-2.49) for high-sensitivity C-reactive protein (hsCRP). When Lp-PLA2 and inflammatory markers were simultaneously included in the full model, the corresponding odds ratios were 1.81 (95% CI, 1.14-3.68) for Lp-PLA2, 1.15 (95% CI, 0.49-2.69) for homocysteine, 1.21 (95% CI, 0.88-5.57) for fibrinogen, 0.98 (95% CI, 0.51-3.85) for apolipoprotein B and 1.23 (95% CI, 1.12-3.51) for hsCRP. Lp-PLA2 levels were significantly and independently associated with PAD following adjustment for other inflammatory markers. These findings reflect the potential role of circulating Lp-PLA2 as a marker of atherosclerosis.