Fibrinogen alpha and beta gene polymorphisms in pediatric stroke--case-control and family based study.

BACKGROUND/PURPOSE: Data on the role of the -455G > A polymorphism of the gene encoding ß fibrinogen subunit (FGB) and the Thr312Ala polymorphism of the gene for the α fibrinogen subunit (FGA) in childhood ischemic stroke are insufficient. Therefore the aim of the study was to evaluate a possible association between these two polymorphisms and arterial ischemic stroke. METHODS: The study group consisted of 85 children after ischemic stroke, 146 of their parents and 159 controls. Both polymorphisms were genotyped using the restriction fragment length polymorphism method. Two study designs were used: a case-control model and a family-based transmission-disequilibrium test. Statistica 7.1 and EpiInfo 6 softwares were used in all analyses. RESULTS: In the TDT test, a tendency to a higher transmission of the 312Ala allele of the FGA gene and the -455A allele of the FGB gene was observed, however, it was statistically non-significant. The frequencies of alleles and genotypes of both FGA and FGB genes polymorphisms did not differentiate children from both groups also in the case-control model. Additive or synergistic effects between FGA and FGB genes polymorphisms were not observed. CONCLUSION: An analysis of the results obtained in this study and a critical review of previously published data indicate that examined gene polymorphisms are not related to ischemic stroke in children.

First observation of HO˙ reactivity in water under high energy ions at elevated temperature.

This communication reports the first observation of the formation of HO˙ produced under two different High energy ion beams, (18)O(8+) and (36)Ar(18+) having Linear Energy Transfers (LET) of 65 and 350 eV nm(-1) respectively, at temperatures up to 411 K. Both scavenging with various concentrations of SCN(-) and heavy-ion pulse radiolysis methods are used with an original temperature and pressure regulated optical cell. Deconvolution of kinetics is used to analyze the evolution of HO˙ track segment yields as a function of time and temperature. It takes care of involving the ionic strength effect and Arrhenius expression in the rate constants correction. The results show a fast decay of HO˙ yields in the 10(-10)-10(-8) s range which denotes an efficient reactivity of this species in the track structure of the ion beam. This effect is enhanced with the lowest LET of O(8+). Increasing the temperature also accelerates the decays for both ions. These observations are discussed in terms of temperature activation of reactions and the track structure exhibiting the formation of HO˙ in a "low LET" penumbra around the ionization tracks. HO˙ track segment yields at 100 ns, of 0.4 × 10(-7) and 0.6 × 10(-7) mol J(-1), respectively for 350 and 65 eV nm(-1), are not affected by temperature.

Implementation of laser induced fluorescence in a pulse radiolysis experiment--a new way to analyze resazurin-like reduction mechanisms.

Resazurin (RNO) reduction by hydrated electrons produces a fluorescent molecule: resorufin (RN). To take advantage of RN fluorescence, a novel setup is designed by implementing fluorescence detection induced by laser in a pulse radiolysis experiment. Time resolved fluorescence spectra were recorded with a fast gated intensified CCD camera during the reduction of RNO from µs to ms. Two 532 nm laser types have been used to describe the short µs range by a 5 ns Q-switch laser and the µs-ms range by a CW DPSS laser. By fitting the simulated model to the experimental data a second order rate constant of 10(9) M(-1) s(-1) was re-evaluated. This method should be considered in the near future in many in situ and real time measurements for evaluating radical production.

The plasminogen activator inhibitor-1 gene polymorphism in determining the risk of pediatric ischemic stroke--case control and family-based study.

Pediatric ischemic stroke, though relatively rare, remains an important medical problem since 20-40% of patients have recurrent strokes and 50-85% of them suffer from long-term neurological deficits. Approximately 20-50% of the affected children have prothrombotic disorders, therefore upon looking for possible genetic causes of the disease we focused on the plasminogen activator inhibitor (PAI-1)--the major inhibitor of fibrinolysis. The aim of the present study was to investigate a possible association between the -675_-674insG PAI-1 gene polymorphism and pediatric ischemic stroke. The study population consisted of 343 individuals: 70 children with ischemic stroke, 140 their biological parents and 133 control children. The PAI-1 gene polymorphism was genotyped using the restriction fragment length polymorphism and was visualized by AgNO3 staining. The transmission/disequilibrium test showed exactly the same transmission of alleles from parents to the affected children (37:37). The case-control model also did not reveal any statistical significance in alleles and genotypes distribution between patients and control children. The obtained results suggest that the 4 G/5 G polymorphism of the PAI-I gene is not a risk factor of ischemic stroke in Polish children.