Rapid determination of gross alpha-activity in water by coprecipitation

U radu je izložena brza i jednostavna metoda za određivanje ukupne alfa aktivnosti u vodi. Opisana metoda podrazumeva kvantitativnu koprecipitaciju radijuma Ba+2 jonima i naknadnu koprecipitaciju aktinida sa Fe+3 jonima uz kontrolu pH taloženja. Za merenje ukupne alfa aktivnosti koristi se ZnS(Ag) scintilacioni detektor.In this work, a rapid and easy method for the determination of gross alpha activity in water is presented. The method described here is a coprecipitation of radium with barium and subsequent coprecipitation of the actinides with Fe+3 carrier. For determination of gross alphaactivity is used ZnS(Ag) scintillation detector.XXV Simpozijum Društva za zaštitu od zračenja Srbije i Crne Gore, Kopaonik, 30.9 do 2.10. 2009

Influence of Cyp2c19∗2 Gene Variant on Therapeutic Response during Clopidogrel Treatment in Patients with Carotid Artery Stenosis

Background: Despite the proven clinical effect of oral antiplatelet drugs, a considerable number of patients do not have an adequate response to clopidogrel. The aim of our study was to determine the influence of CYP2C19*2 loss-of-function variant allele on clopidogrel responsiveness in patients with carotid artery stenosis. Methods: One hundred and twelve patients with carotid artery stenosis undergoing endarterectomy were included in this one-year prospective study. All of them received clopidogrel (75 mg daily) for at least 30 days after the intervention. They were followed from the moment of hospital admission. CYP2C19*2 genotyping was performed by TaqMan Assay. The influence of CYP2C19*2 variant allele on clopidogrel platelet reactivity was determined using multiple-electrode aggregometry (MEA). Results: Genotyping results showed that 82 (73.2%) patients were homozygous for wild type, 29 (25.9%) were heterozygous for the CYP2C19*2 allele and 1 (0.9%) was CYP2C19*2 homozygous. After 24 hours, among those with the wild type 29.3% were clopidogrel responders, and in those with the CYP2C19*2 alleles 10%. In the wild type group, 74.4% were clopidogrel responders after 7 days of taking the drug; 82.9% after 30 days of clopidogrel introduction, respectively. In patients with the CYP2C19*2 alleles the number of responders increased up to 46.7% after 7 days; 53.3% after 30 days of taking the drug, respectively. The risk for being a low-responder is higher for the patients heterozygous for the CYP2C19*2 allele vs. wild type (OR 4.250, 95% CI 1.695-10.658, P lt 0.01). Conclusions: The CYP2C19*2 loss-of-function variant allele has significant influence on clopidogrel response in patients with carotid artery stenosis undergoing endarterectomy

Clopidogrel High On-Treatment Platelet Reactivity in Patients with Carotid Artery Stenosis Undergoing Endarterectomy. A Pilot Study

Objectives: A considerable number of patients do not achieve an adequate response to clopidogrel. Our study aimed to evaluate genetic and non-genetic factors as possible risks for clopidogrel high on-treatment platelet reactivity (HTPR) in patients (n=112) with carotid artery stenosis undergoing endarterectomy (CEA). Methods: Using multiple-electrode impedance aggregometry (MEA) the antiplatelet effectiveness of clopidogrel was measured after 24 h, 7 and 30 days of clopidogrel treatment, which was introduced after elective CEA at a dose of 75 mg daily, for at least 30 days. Results: HTPR was observed among 25% patients after clopidogrel therapy for 30 days. Further analysis showed that 53.3% of patients carrying the CYP2C19*2 gene variant had clopidogrel-HTPR, while in the wild type group there were 14.6% (p lt 0.001). Multivariate logistic regression analysis identified the CYP2C19*2 variant allele (OR 4.384; 95% CI 1.296-14.833, p=0.017) and high total cholesterol level (OR 2.090; 95% CI 1.263-3.459, p=0.004) as the only independent risk factors for clopidogrel-HTPR. Conclusion: The CYP2C19*2 gene variant and high total cholesterol level were major factors for clopidogrel-HTPR in patients with carotid artery stenosis undergoing CEA