Enhancing the Air Stability of Dimolybdenum Paddlewheel Complexes: Redox Tuning through Fluorine Substituents.

The optical and electrochemical properties of quadruply bonded dimolybdenum paddlewheel complexes (Mo2PWCs) make them ideal candidates for incorporation into functional materials or devices, but one of the greatest bottlenecks for this is their poor stability toward atmospheric oxygen. By tuning the potential at which the Mo2 core is oxidized, it was possible to increase the tolerance of Mo2PWCs to air. A series of homoleptic Mo2PWCs bearing fluorinated formamidinate ligands have been synthesized and their electrochemical properties studied. The oxidation potential of the complexes was tuned in a predictable fashion by controlling the positions of the fluorine substituents on the ligands, as guided by a Hammett relationship. Studies into the air stability of the resulting complexes by multinuclear NMR spectroscopy show an increased tolerance to atmospheric oxygen with increasingly electron-withdrawing ligands. The heteroleptic complex Mo2(DFArF)3(OAc) [where DFArF = 3,5-(difluorophenyl)formamidinate] shows remarkable tolerance to oxygen in the solid state and in chloroform solutions. Through the employment of easily accessible ligands, the stability of the Mo2 core toward oxygen has been enhanced, thereby making Mo2PWCs with electron-withdrawing ligands more attractive candidates for the development of functional materials.

Occupational dermatoses by type of work in Greece.

BACKGROUND: To elucidate the relationship between seven occupational dermatoses (ODs) and 20 types of work in Greece. METHODS: This was a prevalence epidemiologic study of certain ODs among 4,000 workers employed in 20 types of enterprise, in 104 companies, in 2006-2012, using data from company medical records, questionnaires, occupational medical, and special examinations. The χ(2) test was applied to reveal statistically significant relationships between types of enterprises and occurrence of ODs. RESULTS: A high percentage (39.9%) of employees included in the study population suffered from ODs. The highest prevalence rates were noted among hairdressers (of contact dermatitis: 30%), cooks (of contact dermatitis: 29.5%), bitumen workers (of acne: 23.5%), car industry workers (of mechanical injury: 15%), construction workers (of contact urticaria: 29.5%), industrial cleaning workers (of chemical burns: 13%), and farmers (of malignant tumors: 5.5%). We observed several statistical significant correlations between ODs (acute and chronic contact dermatitis, urticaria, mechanical injury, acne, burns, skin cancer) and certain types of enterprises. There was no statistically significant correlation between gender and prevalence of ODs, except for dermatoses caused by mechanical injuries afflicting mainly men [χ(2) (1) = 13.40, p < 0.001] and for chronic contact dermatitis [χ(2) (1) = 5.53, p = 0.019] afflicting mainly women. CONCLUSION: Prevalence of ODs is high in Greece, contrary to all official reports by the Greek National Institute of Health. There is a need to introduce a nationwide voluntary surveillance system for reporting ODs and to enhance skin protection measures at work.

Contrast-induced acute kidney injury in patients with renal dysfunction undergoing a coronary procedure and receiving non-ionic low-osmolar versus iso-osmolar contrast media.

BACKGROUND: Although the superiority of low-osmolar over high-osmolar contrast agents in prevention of contrast-induced acute kidney injury (CI-AKI) is generally accepted, the relative nephrotoxicity of iso-osmolar over low-osmolar agents has not yet clearly defined. We examined the incidence of CI-AKI according to the type of contrast agent used in a randomized study of ascorbic acid for CI-AKI prevention. METHODS: A total of 222 patients with baseline serum creatinine >or=1.2 mg/dL who were undergoing a coronary procedure and who were randomized to receive ascorbic acid or placebo were evaluated. The iso-osmolar agent iodixanol was used in 144 patients, whereas low-osmolar non-ionic agents were used in 78 patients (iomeprol, n = 40; iobitridol, n = 30; iopentol, n = 8). CI-AKI was defined by an absolute serum creatinine increase of >or=0.5 mg/dL or a relative increase of >or=25% measured 2 to 5 days after the procedure. RESULTS: The groups of patients who received iso-osmolar and low-osmolar non-ionic agents were well balanced in terms of demographic, clinical, and procedural characteristics. The overall CI-AKI incidence was 14.6% for the iso-osmolar iodixanol versus 14.1% for the combined low-osmolar non-ionic agents (iomeprol, 10%; iobitridol, 10%; iopentol, 50%). For iodixanol, the incidence of CI-AKI was 7.4% for patients randomized to receive ascorbic acid and 21.6% for placebo (P = 0.02). The corresponding incidences for the low-osmolar non-ionic agents were 9.1% and 20.6%, respectively (P = 0.19). CONCLUSION: No differences in CI-AKI incidence were apparent among patients receiving non-ionic iso-osmolar iodixanol and non-ionic low-osmolar contrast agents. The preventative effect of ascorbic acid was also similar.

Effect of balloon valvuloplasty in patients with severe aortic stenosis on levels of N-terminal pro-B-type natriuretic peptide.

Plasma levels of brain natriuretic peptide (BNP) have been shown to correlate to aortic stenosis severity and are predictive of symptom development and survival. They also predict postoperative outcomes after valve replacement in patients with aortic stenosis. The early evolution of N-terminal-pro-BNP (NT-pro-BNP) levels after 50 aortic balloon valvuloplasty procedures performed in 45 patients was investigated. The mean NT-pro-BNP concentration decreased from 7,048 +/- 7,636 pg/ml at baseline to 5,309 +/- 6,150 pg/ml at 1 to 3 days after the procedure (mean difference 1,739 pg/ml, 95% confidence interval 804 to 2,675, p = 0.001). The absolute reduction in NT-pro-BNP levels correlated to the reductions in the maximum and mean transvalvular pressure gradients (on echocardiography: c = 0.57, p = 0.004, and c = 0.54, p = 0.012, respectively; invasively: c = 0.54, p = 0.025, and c = 0.39, p = 0.019). In conclusion, NT-pro-BNP levels decrease early after aortic balloon valvuloplasty in patients with severe aortic stenosis at high surgical risk.

Effect of lipid levels and lipid-lowering therapy on restenosis after coronary artery stenting.

BACKGROUND: Recent experimental and clinical data suggest that lowering serum lipid levels with statins may prevent or delay the process of restenosis. The purpose of this trial is to determine whether lipid levels relate to restenosis and/or whether statin therapy can prevent or delay the process of restenosis after intracoronary stenting. METHODS: One hundred thirty-six patients who underwent single coronary artery stenting from June 1995 to June 1997 in our institution were included in the study. All these patients were followed for at least 9 months (mean 392+/-148 days) for major adverse cardiac events (MACE). We defined as MACE the occurrence of death, myocardial infarction, or need for target lesion revascularization. From this cohort, 103 patients had at least one lipid parameter from the lipid profile evaluated within 2 months from the date of the procedure. Patients who had the stent because of an acute myocardial infarction were included in the study only if their lipid profile was evaluated before or at least 6 weeks after the event. Patients with triglyceride levels above 500 had both triglyceride and low-density lipoprotein cholesterol levels excluded from the statistical analysis. Patients were divided into two groups based on lipid levels: normal (Group I; n=31) and elevated (Group II; n=72). Patient outcomes were also analyzed by statin therapy use. RESULTS: There was no significant difference in MACE rates between the two groups when outcomes were analyzed by lipid levels (22.6% versus 20.8% P=0.8). Furthermore, outcomes were analyzed by use of statin therapy (Group III, n=53, on statin versus Group IV, n=50, on no statin). There was also no difference in MACE rates between the two groups (20.8% versus 22%; P=0.8). CONCLUSION: The process of restenosis has unique features that differentiate it from atherosclerosis. Although lipid-lowering therapy is crucial in delaying the process of atherosclerosis, its role in the prevention of restenosis is yet to be proven.

Prospective native coronary artery stenosis treated with sirolimus-eluting stent (ONASSIS) registry--acute results and mid-term outcomes: a single-center experience.

BACKGROUND: Encouraging results with the use of the sirolimus-eluting stent (SES) have been recently presented in several multi-center trials. In the present study, the short- and mid-term clinical outcomes of the SES in everyday clinical practice of interventional cardiology were compared with a strategy using conventional bare metal stents. METHODS: In a total of 530 consecutive patients (males 86%, mean age 61 +/- 10 years) who had been treated with a SES were compared with a control group of 398 patients (males 87%, mean age 59 +/- 11 years) treated with a bare metal stent before the use of SES. In-hospital results and clinical outcomes during follow-up (11.22 +/- 3.4 versus 11.41 +/- 3.1 months) were obtained. RESULTS: Patients treated with SES had more risk factors for coronary artery disease or multivessel disease compared to those with treated bare metal stent. The clinical success rate was 99.6% in the SES group and 98.5% in the bare metal stent group (p = ns), and non-Q-wave myocardial infarction (MI) occurred in 5.7% and 4.0% of patients, respectively. The incidence of death or MI during follow-up was not different (1.1% versus 1.3% and 0.8% versus 1.8%; p = ns). Percutaneous or surgical revascularization for target lesion restenosis was required in 2.1% of patients treated with SES and in 10.1% of those with bare metal stents (p < 0.001), and the event-free survival from death, cerebrovascular accident, MI or any percutaneous or surgical revascularization was 93.13% and 83.63%, respectively (p < 0.01). CONCLUSIONS: The implantation of the SES is associated with excellent in-hospital and mid-term results, mainly because of dramatic reductions in the need for repeat revascularization, despite a higher risk factor profile and more complex lesion characteristics.

Ascorbic acid prevents contrast-mediated nephropathy in patients with renal dysfunction undergoing coronary angiography or intervention.

BACKGROUND: Contrast agents can cause a reduction in renal function that may be due to the generation of reactive oxygen species. Conflicting evidence suggests that administration of the antioxidant acetylcysteine prevents this renal impairment. The action of other antioxidant agents has not been investigated. METHODS AND RESULTS: We conducted a randomized, double-blind, placebo-controlled trial of ascorbic acid in 231 patients with a serum creatinine concentration > or =1.2 mg/dL who underwent coronary angiography and/or intervention. Ascorbic acid, 3 g at least 2 hours before the procedure and 2 g in the night and the morning after the procedure, or placebo was administered orally. Contrast-mediated nephropathy was defined by an absolute increase of serum creatinine > or =0.5 mg/dL or a relative increase of > or =25% measured 2 to 5 days after the procedure. Contrast-mediated nephropathy occurred in 11 of the 118 patients (9%) in the ascorbic acid group and in 23 of the 113 patients (20%) in the placebo group (odds ratio [OR], 0.38; 95% confidence interval [CI], 0.17 to 0.85; P=0.02). The mean serum creatinine concentration increased significantly in the placebo group (from 1.36+/-0.50 to 1.50+/-0.54 mg/dL, P<0.001) and nonsignificantly in the ascorbic acid group (from 1.46+/-0.52 to 1.52+/-0.64 mg/dL, P=0.07). The mean increase in serum creatinine concentration was greater in the placebo group than in the ascorbic acid group (difference of 0.09 mg/dL; 95% CI, 0.00 to 0.17; P=0.049). CONCLUSIONS: Prophylactic oral administration of ascorbic acid may protect against contrast-mediated nephropathy in high-risk patients undergoing a coronary procedure.