(1R*,21S*,22R*,24S*)-Methyl ethyl 2-[23-hy-droxy-22,24-diphenyl-8,11,14-trioxa-25-aza-tetra-cyclo-[19.3.1.0(2,7).0(15,20)]penta-cosa-2,4,6,15(20),16,18-hexaen-25-yl]but-2-enedioate.

The title compound, C40H41NO8, is a product of the reduction of the cyclic carbonyl group of the γ-piperidone subunit of the aza-14-crown-4 ether with subsequent re-esterification of its dimethyl butenoate substituent into a monoethyl monomethyl group. The aza-crown macrocycle exhibits a bowl conformation with a dihedral angle of 70.82 (5)° between the benzene rings fused to it. The piperidine ring adopts a chair conformation and the methyl ethyl ethyl-enedi-carboxyl-ate fragment has a cis conformation, with a dihedral angle of 66.51 (7)° between the two carboxyl-ate groups. The ethyl group is disordered over two sites with occupancies of 0.70 (1):0.30 (1). In the crystal, mol-ecules form inversion dimers, via pairs of O-H⋯O hydrogen bonds, that stack along the a axis.

Molecular epidemiology of hepatitis A in St. Petersburg, Russia, 1997-2003.

The molecular epidemiology of hepatitis A virus (HAV) strains circulating in the St. Petersburg and Karelia regions was studied during 1997-2003. Hepatitis A virus RNA was isolated from both clinical samples (stools or sera) and environmental samples (sewage water). RT-PCR was carried out using different primer pairs from the VP1/2A and VP1 genomic regions, the variable parts of the HAV genome. PCR products were sequenced and 306 nucleotides from the VP1/2A and 332 nucleotides from the VP1 region were used for phylogenetic analysis. The results show that the IA subtype was the most common during the follow-up period: >90% of the isolated HAV strains belonged to that subtype. The HAV strains found in intravenous drug users belonged to subtypes IA and IIIA. Only one out of a total of 88 sequenced strains was of the IB subtype. The subtypes IB and IIIA were found only in 2001-2003, which suggests that new strains were introduced into the endemic situation. The results indicate the usefulness of molecular epidemiological methods in studying changes in the circulating HAV strains and in tracing transmission routes.

Lack of association between circulating levels of plasma oxidized low-density lipoproteins and clinical outcome after coronary stenting.

BACKGROUND: We undertook this study to investigate whether there is an association between circulating oxidized low-density lipoproteins (OxLDLs) and outcome after coronary stenting. METHODS: The study included 687 patients with coronary artery disease who underwent coronary stenting. Oxidized low-density lipoproteins were measured before coronary angiography. The median of OxLDL concentrations was 67.7 U/L. Patients were divided into 2 groups: the group with OxLDL levels < median (low OxLDL group, n = 345) and the group with OxLDL levels > or = median (high OxLDL group, n = 342). The combined incidence of major adverse cardiac events (death, myocardial infarction, and target vessel revascularization) was the primary end point. Angiographic restenosis was also evaluated. RESULTS: The combined incidence of death, myocardial infarction, and target vessel revascularization was 27.2% (n = 94) in the low OxLDL group and 25.4% (n = 87) in the high OxLDL group (OR .92, 95% CI 0.68-1.23, P = .59). At 6-month angiography, restenosis was found in 28.1% of the patients (n = 74) in the low OxLDL group and in 24.2% of the patients (n = 61) in the high OxLDL group. (P = .31). CONCLUSION: Our study shows no association between circulating levels of OxLDL and restenosis or other adverse events in patients with coronary artery disease after coronary stenting.

Oxidized low density lipoproteins, statin therapy and severity of coronary artery disease.

BACKGROUND: The impact of statin therapy on the association between circulating levels of oxidized low density lipoproteins (OxLDL) and severity of coronary artery disease (CAD) has not been studied. METHODS: OxLDLs were measured in 687 patients with angiographically proven CAD (320 patients, 46.6% on statin therapy and 367 patients, 53.4% not on statin therapy on admission) using the Mercodia Oxidized LDL Enzyme-Linked Immunosorbent Assay (ELISA). RESULTS: Patients on statin therapy had lower levels of OxLDL (median [interquartile range]; 63.9 U/L [53.9; 79.8] versus 72.3 U/L [58.4; 86.1], P<0.001) and C-reactive protein (3.0 mg/L [1.2; 6.6] versus 4.0 mg/L [1.7; 13.1], P<0.001) than patients not on statins. Multivariable analysis showed that statin therapy was an independent predictor of lower levels of OxLDL (P=0.0001). In univariate analysis, OxLDL level did not differ significantly among the patients with 1-, 2-or 3-vessel disease (70.5 U/L [57.5; 85.6], 66.3 U/L [53.8; 82.6] and 68.2 U/L [57.0; 83.4], respectively, P=0.26). Multivariable logistic regression analysis showed that OxLDL was an independent correlate of angiographic severity of CAD (P=0.04) and that there was an interaction (P=0.038) between statins and OxLDL in that the increased levels of OxLDL were associated with more extensive CAD. CONCLUSION: Patients with CAD who receive statins have lower levels of OxLDL and an attenuation of the relationship between circulating levels of OxLDL and CAD severity compared with patients who do not receive statins.

Antiplatelet effects of a 600 mg loading dose of clopidogrel are not attenuated in patients receiving atorvastatin or simvastatin for at least 4 weeks prior to coronary artery stenting.

AIMS: To test prospectively whether the antiplatelet effect of a 600 mg loading dose of clopidogrel is attenuated in patients receiving atorvastatin and simvastatin for at least 4 weeks prior to coronary artery stenting. METHODS AND RESULTS: Blood samples were obtained at least 2 h after receiving 100 mg aspirin and 600 mg clopidogrel and prior to coronary stenting from 90 patients without statin therapy and 90 patients with statin (atorvastatin and simvastatin) therapy for at least 4 weeks. Maximal and residual platelet aggregation was evaluated with optical aggregometry in response to ADP (5 and 20 micromol/l). Surface expression of IIb/IIIa (CD61) and P-selectin (CD62) was assessed with whole blood flow-cytometry at baseline and following stimulation (5 and 20 micromol/l ADP). Inhibition of ADP-induced platelet aggregation was not impaired in the presence of concomitant statin therapy. Moreover, patients with and without statin therapy did not differ in respect to all flow-cytometric parameters obtained. CONCLUSION: The antiplatelet effect of a high, 600 mg loading dose of clopidogrel is not diminished in patients receiving atorvastatin and simvastatin for at least 4 weeks prior to coronary stenting.

Pharmacokinetics of clopidogrel after administration of a high loading dose.

The adenosine diphosphate (ADP) receptor P2Y12 blocking agent clopidogrel is clinically proven to be efficient in preventing thrombotic events. However, its therapeutic value is limited by an, as yet poorly explained, interindividual heterogeneity in platelet inhibition. To evaluate possible pharmacokinetic determinants of this response variability, we developed a sensitive and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) assay for quantification of unmodified inactive clopidogrel, its inactive carboxyl metabolite, and its active thiol metabolite in plasma. Analyte concentrations and platelet aggregation were assessed in ten healthy volunteers receiving an oral load of 600 mg clopidogrel. Subjects showed marked inter-individual differences in maximal platelet inhibition and in plasma pharmacokinetics. Univariate regression revealed linear correlations between maximal antiplatelet effect and peak plasma concentrations (cmax) of unchanged clopidogrel (r=0.76; p=0.01), of the carboxyl metabolite (r=0.70; p=0.03), and of the thiol metabolite (r=0.73; p=0.02), as well as linear correlations between cmax values of clopidogrel and its metabolites. This indicates that the response variability is predominantly caused by individual differences in clopidogrel absorption and that other factors, such as ADP receptor reactivity or differences in bioactivation of clopidogrel, do not play a major role.

Loading with 600 mg clopidogrel in patients with coronary artery disease with and without chronic clopidogrel therapy.

BACKGROUND: It is not known whether further suppression of platelet function can be achieved with clopidogrel beyond that provided by currently recommended loading and maintenance doses. We performed a comparative assessment of the antiplatelet effects of a 600-mg loading dose of clopidogrel given to patients with and without chronic clopidogrel therapy. METHODS AND RESULTS: Those eligible for this prospective study were aspirin-treated patients with suspected or documented coronary artery disease admitted to hospital for coronary angiography. Two series of 20 consecutive patients each were assessed in this study. The first series included patients who had never received clopidogrel (first-use group); the second series included patients on chronic therapy with a daily dose of 75 mg clopidogrel for > or =1 month (chronic therapy group). Blood samples were drawn before and 6 hours after oral administration of 600 mg clopidogrel for aggregometry and flow cytometry studies. In the first-use group, loading with 600 mg clopidogrel inhibited ADP 5 micromol/L-induced platelet aggregation from 90+/-9% to 51+/-19% (P<0.001). In the chronic therapy group, loading with 600 mg clopidogrel yielded further inhibition of ADP 5 micromol/L-induced platelet aggregation in addition to that achieved by the maintenance dose of 75 mg/d, from 52+/-14% to 33+/-12% (P<0.001). In both groups, 600 mg clopidogrel loading significantly inhibited ADP-induced expression of glycoprotein IIb/IIIa and P-selectin receptors. CONCLUSIONS: Further platelet inhibition can be achieved with clopidogrel in addition to that provided by currently recommended loading and maintenance doses. Higher doses may be warranted after assessment of their clinical efficacy and safety.

ABO locus O1 allele and risk of myocardial infarction.

An association between ABO blood group and myocardial infarction (MI) has been described. One probable mechanism underlying this association is the influence of ABO blood group on plasma von Willebrand factor (vWF) levels. We conducted this genetic study to test whether the ABO O1 allele is associated with low vWF plasma levels and with a reduced risk of MI. Cases consisted of 793 consecutive, angiographically examined patients with either acute or prior MI. As controls served 340 angiographically examined patients with neither coronary artery disease nor signs of MI. ABO1 locus alleles (A1, A2, B, O1, O2) were identified with polymerase chain reaction and fluorogenic probes. The distribution of O1 alleles in the MI group versus the control group was: no O1 allele (15.4%/10.0%), one O1 allele (49.7%/50.0%) and two O1 alleles (34.9%/40.0%) (P = 0.035). O1 allele carriage was associated with a 39% reduction in the risk of MI unadjusted odds ratio, 0.61; 95% confidence interval, 0.41-0.91). The significant association was maintained after adjustment for other cardiovascular risk factors. vWF antigen levels correlated with the number of O1 alleles (P = 0.00003) in a separate control group (n = 164). Carriage of the O1 allele is associated with a decreased risk of myocardial infarction, with homozygosity providing the greatest protection.

PlA polymorphism of the glycoprotein IIIa and efficacy of reperfusion therapy in patients with acute myocardial infarction.

The Pl(A) polymorphism of the platelet glycoprotein IIIa gene is associated with altered platelet function and response to antiplatelet drugs. We sought to assess whether the Pl(A) polymorphism influences myocardial salvage achieved by reperfusion therapy in patients with acute myocardial infarction. We analyzed 292 patients enrolled in 2 randomized trials that compared stenting plus abciximab with thrombolysis (alteplase alone or alteplase plus abciximab) in acute myocardial infarction. Patients were genotyped for the Pl (A) polymorphism using polymerase chain reaction with fluorogenic probes. Technetium-99m sestamibi was injected before and 1-2 weeks after reperfusion treatment. The scintigrams enabled the calculation of the initial perfusion defect, final infarct size, and the proportion of initial defect salvaged by reperfusion (salvage index). Clinical follow-up was done up to 18 months after primary treatment. The genotype distribution was as follows: Pl (A2/A2) in 3.4%, Pl (A1/A2) in 24.7% and Pl (A1/A1) in 71.9% of patients. There were no significant differences between Pl( A2) allele carriers and Pl(A1/A1) patients in salvage index (0.4+/-0.50 vs. 0.4+/-0.43, respectively, P=0.48), final infarct size (16.8+/-20.8% vs. 18.4+/-19.1% of left ventricle, respectively, P=0.46) as well as 18-month mortality (8.5% vs.7.1%, respectively, P=0.69). The lack of relationship between Pl(A2) allele and myocardial salvage was observed for both reperfusion strategies, stenting and thrombolysis. Thus, these findings show that the functional Pl(A) polymorphism of platelet glycoprotein IIIa has no influence on the degree of myocardial salvage achieved by reperfusion therapies in patients with acute myocardial infarction.

Association of a genetic variant of endothelial nitric oxide synthase with the 1 year clinical outcome after coronary stent placement.

AIMS: Endothelial nitric oxide synthase (eNOS) catalyzes the formation of nitric oxide which has vasodilatory, antithrombotic, antiinflammatory and antiproliferative properties. The TT genotype of the single nucleotide polymorphism 894 G/T, located in exon 7 of the eNOS gene, was found to be associated with coronary spasm, coronary artery disease (CAD) and myocardial infarction (MI). We investigated the possibility that the 894 TT genotype has an unfavorable impact on the angiographic and clinical outcome after the placement of stents in coronary arteries. METHODS AND RESULTS: Our study included 1850 patients with CAD who were treated with stent implantation. Major adverse clinical events, including death, MI, and target vessel revascularization, were recorded for 1 year after the intervention. Patients with genotype 894 TT had an increase in the risk of death or MI (hazard ratio 2.14, 95% confidence interval (CI) 1.23-3.72; p=0.007), if compared with G allele carriers. TT patients showed no significant increase in the risk for angiographic restenosis (odds ratio (OR) 1.11, 95% CI 0.78-1.56; p=0.56) and target vessel revascularization (OR 1.21, 95% CI 0.82-1.78; p=0.34). CONCLUSIONS: In comparison with eNOS 894 G allele carriers, patients of the TT genotype were at an increased risk of death or MI within 1 year after coronary artery stenting.

G protein beta 3 subunit 825T allele carriage and risk of coronary artery disease.

C825T polymorphism in the G protein beta3 subunit gene (GNB3) is associated with increased transmembrane signal transduction via adenylyl cyclase inhibiting G (G(i)) proteins. We tested whether GNB3 C825T is associated with an increased risk of coronary artery disease (CAD). Genotypes were determined with polymerase chain reaction and allele-specific fluorogenic probes. Angiographically examined, consecutive patients (n=998) with CAD and angiographically examined, sex- and age-matched controls (n=340) with no evidence of CAD were studied. The proportion of T allele carriers was significantly higher in the group with CAD compared with the control group (55.6 vs. 48.5; P=0.02). T allele carriage was associated with a 33% increase in the unadjusted risk (OR 1.33 [95% confidence interval, 1.04-1.70]) and a 37% increase in the adjusted risk (OR from the multivariate model 1.37 [95% CI, 1.06-1.76]) for CAD. Moreover, an increase in T allele carriage was associated with an increase in disease severity (P=0.006; test for trend). The strongest association was observed between T allele carriage and three-vessel disease (unadjusted OR 1.47 [95% CI, 1.10-1.96]). Thus, carrying this allele is associated with the presence as well as the severity of CAD.