Experimental and numerical studies of the scattering of light from a two-dimensional randomly rough interface in the presence of total internal reflection: optical Yoneda peaks.

The scattering of polarized light from a dielectric film sandwiched between two different semi-infinite dielectric media is studied experimentally and theoretically. The illuminated interface is planar, while the back interface is a two-dimensional randomly rough interface. We consider here only the case in which the medium of incidence is optically more dense than the substrate, in which case effects due to the presence of a critical angle for total internal reflection occur. A reduced Rayleigh equation for the scattering amplitudes is solved by a rigorous, purely numerical, nonperturbative approach. The solutions are used to calculate the reflectivity of the structure and the mean differential reflection coefficient. Optical analogues of Yoneda peaks are present in the results obtained. The computational results are compared with experimental data for the in-plane mean differential reflection coefficient, and good agreement between theory and experiment is found.

The prognostic utility of D-dimer and fibrin monomer at long-term follow-up after hospitalization with coronary chest pain.

D-dimer and fibrin monomer both reflect a prothrombotic potential. There are limited data available comparing these two markers of activated coagulation in a prospective manner in an unselected patient population presenting to the emergency department with chest pain. In addition, their role in risk stratification in patients with acute coronary syndrome is still under evaluation. Therefore, we wanted to assess the prognostic value of these markers with respect to long-term all-cause mortality in 871 patients admitted to the emergency department. Blood samples were obtained immediately following admission. After a follow-up period of 24 months, 123 patients had died. In the univariate analysis, both D-dimer and fibrin monomer predicted all-cause mortality within 2 years with an odds ratio of 7.78 (95% confidence interval, 3.95-15.33) and 4.19 (95% confidence interval, 2.42-7.28), respectively, in the highest quartile (Q4) compared with the lowest quartile (Q1). However, in the multivariable logistic regression model for death within 2 years, the odds ratio of D-dimer and fibrin monomer was 1.80 (95% confidence interval, 0.81 to 3.97) and 1.04 (95% confidence interval, 0.53 to 2.04) in Q4 compared with Q1, respectively, and added no prognostic information above and beyond age, known coronary heart disease, B-type natriuretic peptide and the index diagnoses of ST-segment elevation myocardial infarction, non-ST-segment elevation myocardial infarction and unstable angina pectoris. In an unselected patient population hospitalized with chest pain and potential acute coronary syndrome, neither D-dimer nor fibrin monomer provided complementary prognostic information to established risk determinants during long-term follow-up.

The effect of primary percutaneous coronary intervention as compared to tenecteplase on myeloperoxidase, pregnancy-associated plasma protein A, soluble fibrin and D-dimer in acute myocardial infarction.

INTRODUCTION: Acute coronary reperfusion is accomplished pharmacologically with intravenous thrombolytic therapy or mechanically with primary percutaneous coronary intervention (PCI). METHODS: We have determined the immediate effects of the main coronary reperfusion procedures on the plasma concentrations of myeloperoxidase (MPO), pregnancy-associated plasma protein A (PAPP-A), fibrin monomer (FM) and D-dimer (DD). We studied a total of 38 patients admitted for ST-segment elevation infarct (STEMI). 18 patients were given thrombolytic therapy with tenecteplase and 20 were treated with primary PCI. RESULTS: The plasma concentrations of PAPP-A increased by a factor of six to eight times (p<0.001) following both reperfusion therapies. No significant increase was observed for MPO by either procedure. DD and FM concentrations both increased significantly following thrombolytic therapy, p=0.000, whereas only minor increases, although statistically significant for FM (p=0.013), were noted after PCI. DD and FM were highly correlated prior to the two treatment regimens (R=0.91), and were still highly correlated after PCI (R=0.94) and thrombolytic therapy (R=0.86). No correlation was demonstrated between PAPP-A and markers of activated coagulation. CONCLUSIONS: This is the first report of a significant rise in the plasma concentration of PAPP-A after PCI as compared to thrombolytic treatment (p=0.002) and may indicate a greater impact of PCI than that of thrombolytic therapy on target coronary plaques.

Long term influence of regular intake of high dose n-3 fatty acids on CD40-ligand, pregnancy-associated plasma protein A and matrix metalloproteinase-9 following acute myocardial infarction.

Pregnancy-associated plasma protein A (PAPP-A) and matrix metalloproteinase 9 (MMP-9), both zinc-binding endopeptidases, are abundantly expressed in ruptured and eroded plaques in patients with acute coronary syndromes (ACS). The adhesion molecule CD-40 ligand (CD40L), expressed on activated platelets and T-lymphocytes, can activate metalloproteinases and thereby promote plaque-rupture. N-3 fatty acids, through their anti-inflammatory and anti-thrombotic properties, might reduce the levels of these proatherosclerotic markers and thereby the development of ACS. 300 patients were randomized on day 4 to 6 following an acute myocardial infarction (MI) to receive either 4 g of n-3 fatty acids or a similar daily dose of corn oil for at least one year. We compared levels of PAPP-A, MMP-9 and sCD-40 L at baseline and 12 months in each group, and also looked for inter-group changes. In the omega-3 group, the median level of PAPP-A rose from 0.47 mU/l to 0.56 mU/l (p < 0.001). In the same group, sCD-40 L decreased from a mean baseline value of 5.19 ng/ml to 2.45 ng/ml (p < 0.001) and MMP-9 decreased nonsignificantly from 360.50 ng/ml to 308.00 ng/ml. Corresponding values for the corn oil group were 0.54 mU/l to 0.59 mU/l for PAPP-A (p = 0.007), 5.27 ng/ml to 2.84 ng/ml for sCD-40 L (p < 0.001) and 430.00 ng/ml to 324.00 ng/ml for MMP-9 (p = ns), respectively. In conclusion; both interventions resulted in a significant rise in PAPP-A, a significant decrease in sCD40L and a non-significant decrease in MMP-9 after 12 months of treatment in MI survivors. No inter-group differences were noted.

Activated factor 12 (FXIIa) predicts recurrent coronary events after an acute myocardial infarction.

BACKGROUND: Activated factor XII (FXIIa) is involved in vascular injury and repair, participating in inflammation, thrombosis, and fibrinolysis. We wanted to test the hypothesis that FXIIa may predict an acute coronary syndrome (ACS) after a myocardial infarction (MI) and to evaluate whether FXIIa is related to global markers of end-stage coagulation and inflammation, including fibrin monomer (FM) and ultrasensitive C-reactive protein (microCRP). METHODS: In a prospective study of 300 patients with acute MI, we evaluated the predictive value of FXIIa in blood samples drawn 4 to 6 days after admission. Cardiac death, re-MI, and troponin-T-positive unstable angina pectoris were registered during a median follow-up period of 1.5 years. RESULTS: In the upper quartile of FXIIa (Q4) (> or =2.23 ng/mL) 32.0% of patients had an ACS as compared with 16.9% of patients with FXIIa in the three lower quartiles (Q1-3, P =.008). Relative risk of recurrent ACS for patients with FXIIa in the Q4 as compared with Q1-3 was 1.89 (95% CI, 1.22 to 2.93). A secondary ACS occurred earlier in patients with FXIIa in the Q4 as compared with those with FXIIa in the Q1-3 (P =.0039). Conventional risk factors as potential confounders were not associated with time to event. FXIIa did not correlate with FM or microCRP, and the FM and microCRP levels were of a similar magnitude in the Q4 as compared with the Q1 and the Q1-3 of FXIIa. CONCLUSIONS: FXIIa predicts recurrent coronary events after MI. The prognostic ability of FXIIa was not reflected by markers of hypercoagulability or inflammation.

Changes in tissue factor and activated factor XII following an acute myocardial infarction were uninfluenced by high doses of n-3 polyunsaturated fatty acids.

Few data exist on the effects of n-3 polyunsaturated fatty acids (PUFAs) on the initiators and endstage products of coagulation following an acute myocardial infarction (MI). We assessed the long-term effects of n-3 PUFAs on postinfarct variations of tissue factor (TF), activated factor XII (FXIIa) and fibrin monomer (FM), and expected additional statin treatment to modify thrombogenicity. Acute MI patients (n = 300) were randomly allocated to a high dose of n-3 PUFAs or corn oil for at least one year. Plasma concentrations of TF, FXIIa and FM were unaffected by n-3 PUFAs as compared to corn oil, and were uninfluenced by additional statin treatment in subgroup analyses. TF decreased (p = 0.0001), while FXIIa increased during the first 6 weeks (p = 0.001). FM remained essentially unchanged during the entire observation period. In conclusion, TF, FXIIa and FM were unaffected by long-term treatment with high- dosed n-3 PUFAs and by additional statin treatment.

Clinical outcome and atherothrombogenic risk profile after prolonged wash-out following long-term treatment with high doses of n-3 PUFAs in patients with an acute myocardial infarction.

BACKGROUND: Sustained effects following withdrawal of n-3 PUFAs are unknown. METHODS: Clinical outcome [cardiac death, resuscitation, recurrent myocardial infarction (MI) or unstable angina pectoris] was assessed after prolonged wash-out following randomised treatment with high-dosed n-3 PUFAs or corn oil for 12-24 months in 300 acute MI patients. Atherothrombogenic risk markers, serum glucose and markers of lipid peroxidation and inflammation were evaluated in 89 out of the 100 last included patients. RESULTS: After a total median observation period of 45 (range 0-53) months no intergroup difference in prognosis was observed for any of the cardiac events. Favourable effects on serum triglycerides and HDL-cholesterol by n-3 PUFAs were lost after washout, but triglycerides decreased in the corn oil as compared to the n-3 group, P < 0.001. The decline in total cholesterol after withdrawal was similar in both groups. No intergroup difference in the change in thiobarbituric acid-malondialdehyde, a marker of lipid peroxidation, ultrasensitive C-reactive protein, homocysteine, glucose or blood platelets was noted at sustained follow-up. CONCLUSION: Clinical outcome was similar in both patient groups, and the atherothrombogenic risk improvement by n-3 PUFAs was lost after prolonged wash-out. Withdrawal did not affect homocysteine, glucose or markers of lipid peroxidation or inflammation.

Serum concentrations of cardiac troponin T in sudden death.

Ischemic heart disease is the most common cause of sudden death of natural causes in most western countries. By autopsy, there may be no gross or histologic evidence of acute myocardial damage unless the patient survived for several hours following the event. Cardiac troponin in serum has become the recommended biochemical marker for myocardial injury in the clinical setting. We performed a prospective study on 102 autopsied subjects at the Central Hospital of Rogaland, Stavanger, Norway. Femoral blood was sampled for subsequent analysis of cardiac troponin T (cTnT). In the subjects with morphologic evidence of recent myocardial injury (n = 34), the mean serum cTnT level was 1.95 microg/L compared with 0.16 microg/L in the subjects with a noncardiac cause of death (n = 35) and 0.61 microg/L in the group with probable sudden cardiac death without morphologic signs of acute myocardial injury (n = 33). The observed differences in mean serum cTnT levels between the groups were statistically significant (P < 0.0001). These data suggest that elevated postmortem serum concentration of cTnT reflects ongoing myocardial damage and may support a diagnosis of cardiac-related death in cases associated with sparse or inconclusive morphologic findings postmortem.

Reduction in homocysteine by n-3 polyunsaturated fatty acids after 1 year in a randomised double-blind study following an acute myocardial infarction: no effect on endothelial adhesion properties.

We hypothesized that n-3 polyunsaturated fatty acids (n-3 PUFAs) as compared to corn oil administered for 1 year following an acute myocardial infarction (MI) may reduce plasma total homocysteine (p-tHcy), ultrasensitive C-reactive protein (microCRP), and the adhesive properties of the endothelium, expressed as soluble E-selectin (sE-selectin) and soluble intercellular adhesion molecule-1 (sICAM-1). In a prospective, randomised, double-blind study, 300 acute MI patients were allocated to highly concentrated n-3 PUFAs (n = 150) or corn oil (n = 150). After 1 year on treatment there was an intergroup difference in p-tHcy in favour of the n-3 group (n = 118), p = 0.022. However, sE-selectin, sICAM-1 and microCRP were unaffected by the treatment. In conclusion, reduction of p-tHcy by long-term n-3 PUFAs treatment was not associated with demonstrable effects on markers of endothelial adhesion properties.