Radiation Response of Large-Area 4H-SiC Schottky Barrier Diodes.

We report on the effects of large-area 4H-SiC Schottky barrier diodes on the radiation response to ionizing particles. Two different diode areas were compared: 1 mm × 1 mm and 5 mm × 5 mm. 6LiF and 10B4C films, which were placed on top of the diodes, were used as thermal neutron converters. We achieved a thermal neutron efficiency of 5.02% with a 6LiF thermal neutron converter, which is one of the highest efficiencies reported to date. In addition, a temperature-dependent radiation response to alpha particles was presented. Neutron irradiations were performed in a JSI TRIGA dry chamber and an Am-241 wide-area alpha source was used for testing the alpha response of the 4H-SiC Schottky barrier diodes.

Angiographic control and percutaneous treatment of myocardial ischemia immediately after CABG.

Perioperative myocardial ischemia is rare but serious complication of CABG. Graft dysfunction, coronary artery thrombosis and incomplete revascularization are main causes. Pharmacological treatment, intra aortic counter pulsation and immediate additional grafting have limited results. Treatment strategy based on coronary angiography findings could lessen the burden of high mortality rate in these patients. The purpose of this study was to analyze the causes of perioperative ischemia and angiography based treatment strategy including percutaneous intervention. We enrolled all 55 consecutive patients that went early coronary angiography for perioperative myocardial ischemia in a prospective longitudinal study. Incorrect graft anastomosis, graft spasm, displacement and dissection were found in 49%, 7%, 5% and 4% of patients, respectively. Acute coronary artery thrombotic occlusion was found in 5% of patients and ischemia due to incomplete revascularization in 6% of patients. In 22% of patients no cause of myocardial ischemia could be detected. There were no complications of coronary angiography. Based on coronary angiography findings percutaneous intervention was performed in 30 patients, additional grafting in 8 patients and no action was taken in 17 patients. Percutaneous intervention with stenting was performed on coronary arteries (78%) and graft anastomosis (22%) with primary success 97%. One anastomosis rupture with treatable tamponade and one lethal stent thrombosis were complications of percutaneous treatment. Overall in hospital mortality was 30%. We concluded that graft dysfunction is usual cause of myocardial ischemia due to incorrect anastomosis and that percutaneous intervention on bypass graft or coronary artery can lessen high mortality rate in these patients.

C-reactive protein gene polymorphisms affect plasma CRP and homocysteine concentrations in subjects with and without angiographically confirmed coronary artery disease.

Human C-reactive protein (CRP) is a reactant involved in the acute phase response and one of the many molecular factors involved in pathogenesis of coronary artery disease (CAD). CRP gene variants potentially mediate CRP plasma concentrations and the development of CAD. 220 Croatian subjects with angiographically confirmed CAD and 132 control subjects were included in the study. CRP gene polymorphisms 1059G/C and -717G/A were determined by RFLPs, using MaeIII and KspI endonuclease, respectively. Plasma concentrations of CRP and homocysteine were determined by immunoturbidimetry and FPIA, respectively. CRP 1059G/C gene variants were significantly associated with CAD (OR = 0.50; 95% CI = 0.27, 0.94; P = 0.032). Wild GG genotype and rare allele C carrier genotypes were 184 and 22 in CAD(+) group, and 101 and 24 in CAD(-) group, respectively. Multivariate analysis with age, gender, BMI, smoking status, hypertension and diabetes as covariates showed that 1059C carriers had lower CRP concentrations in CAD(-) (P = 0.010) and CAD(+) subjects (P = 0.028). This allele was also significantly associated with lower plasma homocysteine concentrations in both groups (P = 0.018 for CAD(-) and 0.002 for CAD(+). There was no significant difference between CAD(+) and CAD(-) subjects in absolute frequencies for CRP -717A/G gene variant, but multivariate analysis showed that carriers of the rarer G allele had significantly higher CRP plasma concentrations in CAD(-) subjects (P = 0.031) and higher homocysteine concentrations in CAD(+) group (P < 0.001). Atherosclerosis is an inflammatory disease resulting from different genetic and environmental factors. Results presented here support the contribution of CRP genetic variations in the development of CAD.

Micro-scale socioeconomic inequalities and health indicators in a small isolated community of Vis Island, Croatia.

AIM: To investigate whether socioeconomic inequalities at a micro-scale, through their effect on major health risk factors and other health indicators, contribute to health status in an isolated island population with demonstrated reduced genetic and environmental variability. METHODS: This cross-sectional study was performed in 2003 and 2004 in the adult population of the island of Vis, Croatia. Participants were recruited from the electoral register. A total of 1024 participants were included in the study, which represented a response rate of approximately 70%. The level of education and household socioeconomic status were used as the socioeconomic status indicators. Associations of these indicators with hypertension, obesity, hyperlipidaemia, smoking, diet indicators, and supplementary vitamins and calcium intake were investigated. Data analysis was performed by multivariate methods. RESULTS: Age and gender were most commonly associated with the presence of major health risk factors. Level of education did not show significant association with any of the investigated risk factors, supplements intake, or with dietary habits. Household socioeconomic status was significantly associated only with excessive alcohol intake (logistic regression odds ratio [OR], 1.85; 95% confidence interval [CI], 1.12-3.07, P=0.016), obesity (OR, 1.78; 95% CI, 1.13-2.81 P=0.013), and high-fat diet (multiple linear modeling F=2.75, P=0.042). CONCLUSION: In isolated communities, socioeconomic stratification may be a less important health determinant than in large general populations, making these populations favorable resource for biomedical research into other health risk factors.

[Myocardial revascularization strategy in patients with acute coronary syndrome]. / Strategija revaskularizacije miokarda u bolesnika s akutnim koronarnim sindromom.

Acute coronary syndrome (ACS) represents a spectrum of conditions caused by activated malignant coronary disease, with one of the following outcomes: stabilization, myocardial infarction or sudden death. The strategies of diagnostic procedures and treatment for ACS have been developed on the basis of differentiation between the two main groups of patients: those with unstable angina pectoris (UAP) and non-ST-segment elevation myocardial infarction (NSTEMI), and those with ST-elevation myocardial infarction (STEMI). The diagnosis and treatment of STEMI patients have both temporal and spatial limitations, where rapid identification and use of revascularization strategy, generally from 6 to not more than 12 hours, are the mainstay of the respective algorithm. In contrast to this, in UAP/NSTEMI patients the nature of the disease usually allows for more time for the diagnosis and choice of most appropriate therapy, whereas the chance of saving practically the entire myocardial area is much greater. Proposals of the possible algorithms for the procedures to be used in the diagnosis and management of ACS, based on the real possibilities available in the Republic of Croatia, and some our own results are presented in this review.

Long-term results and learning curve for radio frequency ablation of accessory pathways.

Radio frequency (RF) catheter ablation of accessory pathways represents an interventional method in modern cardiology that has become the first-line treatment for patients with symptomatic WPW-syndrome. The aim of this study was to analyze: (1) the learning curve for the ablation procedure; (2) procedural parameters and success; and (3) personal assessment of the treatment by the patients. Learning curve analysis included 195 consecutive patients, who underwent ablation between 1991 and 1996. The follow-up survey included 65 consecutive patients. The analysis of the procedural parameters showed significant improvement after 100 cases, implying a completion of the learning curve at this point. Long-term follow-up showed a high success rate for all pathways (95.4%). All procedure parameters indicated significantly higher degree of difficulty for right free-wall and septal pathways, with lowest long-term success rate for right-sided pathways (78.6%). Personal assessment survey showed high acceptance of the treatment; the procedure was described as a significant improvement of overall quality-of-life by 92.3% of patients. The results of this study confirm the catheter ablation of accessory pathways--in particular after completion of the learning curve--as a low-risk and highly efficient treatment for symptomatic WPW-syndrome, with a high degree of patient-related acceptance.