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  • Author or Editor: G Lázár x
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Abstract

Pulmonary arterial hypertension (PAH) is a rare and progressive disease, characterized by increased vascular resistance leading to right ventricle (RV) failure. The extent of right ventricular dysfunction crucially influences disease prognosis; however, currently no therapies have specific cardioprotective effects. Besides discussing the pathophysiology of right ventricular adaptation in PAH, this review focuses on the roles of growth factors (GFs) in disease pathomechanism. We also summarize the involvement of GFs in the preservation of cardiomyocyte function, to evaluate their potential as cardioprotective biomarkers and novel therapeutic targets in PAH.

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Abstract  

Radon activity concentrations of 1077 homes were surveyed in two villages of Northern Hungary to obtain the yearly averages. The distribution of indoor radon activity concentrations covered a wide range. Cancer incidences of all the 2680 inhabitants for the last 30 years were also studied in these villages in order to establish a possible correlation with radon exposure. The methods applied in the analysis allow to draw up statistically supported statements concerning the relative cancer risks of different radon level groups. The results show that among non-smoking middle-aged women the frequency of cancer, regardless to tumor types, is lower for those who live in residential radon activity concentrations of a level between 110 and 185 Bq.m-3 compared to those living in radon levels outside this range. A minimum value in the cancer frequency exists at a level of significance p<0.008 (determined with the help of Fisher's test). In general, the present study corroborates the outcome of other studies demonstrating the existence of a biopositive effect, and suggests a wider concept of radon health effects.

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The effect of potassium channel blockers tetraethylammonium and 4-aminopyridine was examined on the elevated K+ concentration-induced microglial activation on rat hippocampal slice preparations. Microglial cells were detected by immunohistochemistry with a monoclonal antibody (OX 42) raised against a type 3 complement receptor. During activation the morphology of the microglial cells changes and the staining intensity increases. The degree of microglial activation was determined by measuring the integrated optical density of the cells. Tetraethylammonium and 4-aminopyridine failed to reduce the elevated K+ concentration-induced microglial activation. Both potassium channel blockers, when applied on the hippocampal slices without K+, caused significantly increased microglial activation as compared to the control slices. In order to check whether the functional alteration of the neuronal population induced by 4-aminopyridine caused the activation of the microglial cells, Schaffer collaterals were cut to block spreading of epileptiform hyperactivity of the CA3 pyramidal cells to the CA1 region. No significant differences were found in microglial activation between the CA3 and CA1 regions, indicating that the effect of 4-aminopyridine on microglial cells is independent of the epileptiform activity caused by the drug.

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Exercise-caused metabolic changes can be followed by monitoring exhaled volatiles; however it has not been previously reported if a spectrum of exhaled gases is modified after physical challenge. We have hypothesized that changes in volatile molecules assessed by an electronic nose may be the reason for the alkalization of the exhaled breath condensate (EBC) fluid following physical exercise.Ten healthy young subjects performed a 6-minute running test. Exhaled breath samples pre-exercise and post-exercise (0 min, 15 min, 30 min and 60 min) were collected for volatile pattern (“smellprint”) determination and pH measurements (at 5.33 kPa CO2), respectively. Exhaled breath smellprints were analyzed using principal component analysis and were related to EBC pH.Smellprints (p=0.04) and EBC pH (p=0.01) were altered during exercise challenge. Compared to pre-exercise values, smellprints and pH differed at 15 min, 30 min and 60 min following exercise (p<0.05), while no difference was found at 0 min post-exercise. In addition, a significant correlation was found between volatile pattern of exhaled breath and EBC pH (p=0.01, r=−0.34).Physical exercise changes the pattern of exhaled volatiles together with an increase in pH of breath. Changes in volatiles may be responsible for increase in EBC pH.

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The incidence of post-transplant diabetes mellitus and its effects on the kidney allograft function and morphology were assessed. Patients were divided into three groups according to their glucose metabolism. Risk factors for diabetes were first assessed, and then changes in renal function were checked. Morphological changes in the allografts were examined by protocol biopsies. The overall incidence of diabetes was 16%. The development of diabetes was influenced significantly by the body mass index, the body weight and the age of the recipient. The incidence of diabetes was 8.6% in patients on cyclosporine A therapy and 28.8% in those on tacrolimus (p < 0.05). As to the morphology of the kidney, a significantly higher proportion of the biopsies showed severe interstitial fibrosis/tubular atrophy (p = 0.0004) and subclinical acute rejection ( p = 0.001) in the diabetic group compared to the normal one. This clinical study has revealed that the adverse effect of diabetes on the allograft can be detected with protocol biopsy before the manifestation of a functional deterioration.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: G. Duplâtre, Zs. Kajcsos, T. Goworek, L. Varga, L. Liszkay, I. Billard and K. Lázár

Abstract  

Positron annihilatioin data collected for zeosil (a zeoilite-type solid allowing abundant Psformation) are discussed, with particular attention payed to the longest-lived positronium states as observed in lifetime spectroscopy experiments. To unravel the nature of these components, additional information was sought by applying an extermal magnetic field and by reecording the total energy distributioin of the annihilation radiation. From both the lifetime and the extended Doppler spectra, it is shown that positronium presents a very long-lived component with a relative intensity of ca. 30% and a lifetime close to the intrinsic tripler lifetime (140ns), therefore undergoing almost no pick-off annihilation. From the magnetic field experiments, the contact density parameter has a value of essentially 1, which is characteristic of an unpoerturbed triplet Ps state in vacuo. This positronium state therefore does not appear to interact with the medium.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: L. Varga, L. Liszkay, Zs. Kajcsos, K. Lázár, H. Beyer, G. Onestyák, E. Kótai and L. Lohonyai

Abstract  

In many sorts of zeolites long-living positron components are manifested, connected presumably with Ps-formation in various kinds of free space in the zeolite structure. Literature values demonstrate, however, a broad scasttr of data obtained for assumedly on the same composition of zeolite indicating the possible influence of tehnology, adsorbates, impurities, water content, etc. In the present work spectral changes of the 511 keV annihilation peak and its vicinity are evaluated, applying for the first time a combination of theS and W parameters and the 3-specific left plateau region measured in zeolites. To ensure reproducible experimental conditions, evaluated samples were measured. The data show individual temperature behaviours of the annihilation parameters in the studied temperature range of 90–450 K for each kind of samples. The temperature dependence becomes reproducible after the first heating run. The results are discussed with respect to the evolution of long-living positron and positronium components.

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Summary  

The associations between cancer mortality and median radon levels were examined in 34 Hungarian small villages (with population less than 5000) during the 1984-2000 period. The yearly averages of radon activity concentrations were measured in more than 70 homes in totally 5,081 houses in each village. There were no significant differences in the age distribution and the cancer mortality rate between the studied villages and all Hungarian villages with less than 5000 inhabitants. A previous cohort study in two neighboring villages in Hungary revealed a lower cancer incidence rate among women aged 30-64 in medium radon level (110-185 Bq . m-3). The aim of this study was checking the results of the previous study. Cancer mortality rate was examined in two groups: below and above the median value (110 Bq . m-3) of radon level. The lower or higher radon levels of homes do not result in significant differences concerning cancer mortality rate of males. However, the middle-aged group (30-64 years) of women had more lethal cancer cases in the lower radon level groups (59-109 Bq . m-3) than in the higher ones (110-226 Bq . m-3), the relative cancer risk was 1.3 (95% CI 1.1 to 1.6).

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Abstract  

Ferrisilicates of MFI structure (HZSM-5) with Si/Fe ratios of 27.5, 35 and 67 have been studied by in situ Mössbauer spectroscopy, and the results are correlated with studies on catalytic conversions of toluene. Various species of iron ions are identified from 300 K spectra recorded after combinations of evacuation and reduction at 570 and 670 K, respectively. The roles of identified species are suggested in catalytic processes.

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Summary  

Diffusions of85Sr,137Cs,60Co and125I radionuclides have been studied in borecore samples from Boda siltstone/claystone formation (BCF) under ambient and in situ conditions. In-diffusion (85Sr,137Cs,60Co and125I) and through-diffusion measurements (125I) were performed at ambient conditions, and for iodine, in-diffusion measurements were also carried out at in situ conditions (100 bar, 50 °C). In the case of cationic species carrier-containing solutions were also applied.60Co was detected only in the first slice of borecore at each sample, while137Cs was detected also in the first-, second- and third slices according to the concentration-increase of inactive carrier. Among the investigated cations,85Sr exhibited the fastest diffusion rate with 2.7-6.0 . 10-12m2/s apparent diffusivity values. In the course of in-diffusion measurements 4.7 . 10-11 m 2 /s, during through-diffusion investigations 1.4-1.6 . 10-12m2/s and at in situ conditions 5.0-8.0 . 10-12 m2/s apparent diffusivities were obtained for125I.Modest sorption of125I can also be deduced from the results.

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