Regulation of gap junction function; the role of nitric oxide.

Myocardial ischemia resulting from sudden occlusion of a coronary artery is one of the major causes in the appearance of severe, often life-threatening ventricular arrhythmias. Although the underlying mechanisms of these acute arrhythmias are many and varied, there is no doubt that uncoupling of gap junctions (GJs) play an important role especially in arrhythmias that are generated during phase Ib, and often terminate in sudden cardiac death. In the past decades considerable efforts have been made to explore mechanisms which regulate the function of GJs, and to find new approaches for protection against arrhythmias through the modulation of GJs. These investigations led to the development of GJ openers and inhibitors. The pharmacological modulation of GJs, however, resulted in conflicting results. It is still not clear whether opening or closing of GJs would be advantageous for the ischemic myocardium. Both maneuvers can result in protection, depending on the models, endpoints and the time of opening and closing of GJs. Furthermore, although there is substantial evidence that preconditioning decreases or delays the uncoupling of GJs, the precise mechanisms by which this attains have not yet been elucidated. In our own studies in anesthetized dogs preconditioning suppressed the ischemia and reperfusion-induced ventricular arrhythmias, and this protection was associated with the preservation of GJ function, manifested in less marked changes in electrical impedance, as well as in the maintenance of GJ permeability and phosphorylation of connexin43. Since we have substantial previous evidence that nitric oxide (NO) is an important trigger and mediator of the preconditioning-induced antiarrhythmic protection, we hypothesized that NO, among its several effects, may lead to this protection by influencing cardiac GJs. The hypotheses and theories relating to the pharmacological modulation of GJs will be discussed with particular attention to the role of NO

Népszerű városi fafajok árnyékolóképességének vizsgálata Szegeden

A városi faállomány számos aspektusból kedvezően befolyásolja egy város ökológiai állapotát. Például, klímamódosító potenciálja révén a fás vegetáció pozitívan hat a városi lakosság hőérzetére és komfortérzetére. A mikroklimatikus hatások feltárása céljából végzett terepi mérések, valamint modellfuttatások is kimutatták, hogy a fák elsősorban árnyékhatásuk révén képesek enyhíteni az emberi szervezetet érő hőstressz mértékét. A napsugárzás redukciójának hatékonyságát a lombozat transzmisszivitásának (napsugárzásátereszt őképessége) mérőszámával írhatjuk le, melynek értéke nem csupán fajonként változik, de a lombkorona évszakos változásának és egészségi állapotának is függvénye. Ebben a tanulmányban négy, magyarországi viszonyok között gyakran előforduló városi fafaj (kislevelű hárs – Tilia cordata, japánakác – Sophora japonica, nyugati ostorfa – Celtis occidentalis és fehér vadgesztenye – Aesculus hippocastanum) árnyékolóképességét vizsgáljuk. A városi fás vegetáció – közép-európai klimatikus körülmények között kifejtett – kisléptékű hatására vonatkozóan még kevés az ismeretünk, ezért munkánkkal szeretnénk elősegíteni jövőbeli, ezzel foglalkozó tanulmányok megszületését. Ebből kifolyólag nagy hangsúlyt fektetünk a kutatás módszertani alapjaira, valamint kitérünk a gyakorlati megvalósítás nehézségeire is

More Than a Diamine Oxidase Inhibitor: L-Aminoguanidine Modulates Polyamine-Related Abiotic Stress Responses of Plants

L-aminoguanidine (AG) is an inhibitor frequently used for investigating plant abiotic stress responses; however, its exact mode of action is not well understood. Many studies used this compound as a specific diamine oxidase inhibitor, whereas other studies used it for reducing nitric oxide (NO) production. Recent studies suggest its antiglycation effect; however, this remains elusive in plants. This review summarises our current knowledge about different targets of AG in plants. Our recommendation is to use AG as a modulator of polyamine-related mechanisms rather than a specific inhibitor. In the future overall investigation is needed to decipher the exact mechanisms of AG. More careful application of AG could give more insight into plant abiotic stress responses

Studying the growth characteristics of urban trees using an example from Szeged, Hungary

The spatial expansion of urbanised areas and the steady increase in the urban population, as well as climate change trends, are increasing the need for the development of adequate urban green infrastructure. The social demand for combating climate change is accompanied by the revaluation of green spaces, and in this context woody vegetation plays a key role. In a changing climatic context and under intense anthropogenic stress, the challenge of developing a tree population that is climate-friendly and resistant to disturbance is a major one. In our research, we investigate all growth parameters of the newly planted trees from the start of a street reconstruction involving a complete tree replacement (Gutenberg Street, Szeged). The structural analysis of the revealed not only the growth rate over the 8 years since planting, but also the significant differences between the two sides of the street. In order to find a possible reason for this, we examined (using SAGA GIS software) potential incoming solar radiation of the street, which could explain the significant difference in growth rate. The data collected also provided an opportunity to analyse the allometric relationships. This will partly allow the prediction of the growth rate and can provide baseline data for planning and decision-making processes in the dilemma of whether to retain older trees or plant new stocks

Investigation Of Tree Stands Of Public Spaces In Szeged

In urban areas vegetation (especially woody vegetation) is of utmost importance, since it affects the ecological conditions of the city. Urban trees play an important role in improving urban climate both at the local (city, district) and the micro-level (e.g. in public squares). Establishing and maintaining advanced and detailed information systems necessary for the management of urban tree stands is an important task of environmental and climate-conscious city management. Despite that, few of the Hungarian municipalities have a regularly updated tree database. The city of Szeged started efficient green space management in autumn 2013, when we started the creation of a detailed and up-to-date tree register for the public areas, which has been continuously expanded ever since. The survey of the present study covers the period of the growing season, from late spring to early autumn of 2013. All the trees are included in the survey and quite a number of data are recorded for each individual (e.g. species, age, size parameters, exact location, health status, etc.). The recorded data are paper-based, however they are included in a GIS-based green space inventory software, Greenformatic, where coordinates are associated to each object, while information on the state of the tree, its location and handling can be found in the attribute table. The trees included are mostly concentrated in the inner city of Szeged, but the surveys will gradually cover ever larger areas of the city. The results highlight the fact that the structural attributes of the different species’ populations are formed by the integrated effect of the species’ urban tolerance and planting policies of the past decades. The current database already allows highly complex analysis, which contributes to the well-being of city residents

The Study of Heavy Metal Adsorption on the Surface of Fungi Compost

The heavy meta l adsorption on the surface of fungi compost is one of the alternative technologies. In this study fungi composts were used and we measured the heavy metal adsorption capacities. The laboratorical methods were the preparing solutions of heavy metals, the a dsorptions of heavy metals on the surface of fungi compost by shaking method, the sample degradation and the analytical measurements by ICP - MS. The heavy metal adsorption properties of fungi compost could be used in wastewater treatment because wastewater sometimes contains a high concentration of heavy metals

Study of the degradation patterns of thermophilic fungi from special digested wastewater sludge samples

Digested wastewater sludges have high content of thermophilic fungi because of the anaerobe biodegradation. This study shows the ecophysiological properties (cellulose, hemi-cellulose, lignin and fatty-acid ester degradations) of thermophilic fungi which were isolated from digested wastewater sludge samples. The samples came from three Hungarian wastewater treatment systems. In this study four types of mycological agars were applied. This study shows digestion properties and growing temperature range of eight thermophilic fungal species. This study demonstrated wide ranges of digestion properties. Most of the isolated species are appropriate for degradations of several biopolymers