Protection of the vascular endothelium in experimental situations

One of the factors proposed as mediators of vascular dysfunction observed in diabetes is the increased generation of reactive oxygen species (ROS). This provides support for the use of antioxidants as early and appropriate pharmacological intervention in the development of late diabetic complications. In streptozotocin (STZ)-induced diabetes in rats we observed endothelial dysfuction manifested by reduced endothelium-dependent response to acetylcholine of the superior mesenteric artery (SMA) and aorta, as well as by increased endothelaemia. Changes in endothelium-dependent relaxation of SMA were induced by injury of the nitric oxide radical (·NO)-signalling pathway since the endothelium-derived hyperpolarising factor (EDHF)-component of relaxation was not impaired by diabetes. The endothelial dysfunction was accompanied by decreased ·NO bioavailabity as a consequence of reduced activity of eNOS rather than its reduced expression. The results obtained using the chemiluminiscence method (CL) argue for increased oxidative stress and increased ROS production. The enzyme NAD(P)H-oxidase problably participates in ROS production in the later phases of diabetes. Oxidative stress was also connected with decreased levels of reduced glutathione (GSH) in the early phase of diabetes. After 10 weeks of diabetes, adaptational mechanisms probably took place because GSH levels were not changed compared to controls. Antioxidant properties of SMe1EC2 found in vitro were partly confirmed in vivo. Administration of SMe1EC2 protected endothelial function. It significantly decreased endothelaemia of diabetic rats and improved endothelium-dependent relaxation of arteries, slightly decreased ROS-production and increased bioavailability of ·NO in the aorta. Further studies with higher doses of SMe1EC2 may clarify the mechanism of its endothelium-protective effect in vivo

Deteriorated gene expression of selected calcium transporters in streptozotocin-induced diabetic hearts of Wistar rats

Aim: The aim is to identify the possible changes in the expression of genes, that regulate calcium homeostasis in cardiomyocytes in diabetes mellitus

Multicolour three dimensional structured illumination microscopy of immunolabeled plant microtubules and associated proteins

Abstract Background In the present work, we provide an account of structured illumination microscopy (SIM) imaging of fixed and immunolabeled plant probes. We take advantage of SIM, to superresolve intracellular structures at a considerable z-range and circumvent its low temporal resolution capacity during the study of living samples. Further, we validate the protocol for the imaging of fixed transgenic material expressing fluorescent protein-based markers of different subcellular structures. Results Focus is given on 3D imaging of bulky subcellular structures, such as mitotic and cytokinetic microtubule arrays as well as on the performance of SIM using multichannel imaging and the quantitative correlations that can be deduced. As a proof of concept, we provide a superresolution output on the organization of cortical microtubules in wild-type and mutant Arabidopsis cells, including aberrant preprophase microtubule bands and phragmoplasts in a cytoskeletal mutant devoid of the p60 subunit of the microtubule severing protein KATANIN and refined details of cytoskeletal aberrations in the mitogen activated protein kinase (MAPK) mutant mpk4. We further demonstrate, in a qualitative and quantitative manner, colocalizations between MPK6 and unknown dually phosphorylated and activated MAPK species and we follow the localization of the microtubule associated protein 65-3 (MAP65-3) in telophase and cytokinetic microtubular arrays. Conclusions 3D SIM is a powerful, versatile and adaptable microscopy method for elucidating spatial relationships between subcellular compartments. Improved methods of sample preparation aiming to the compensation of refractive index mismatches, allow the use of 3D SIM in the documentation of complex plant cell structures, such as microtubule arrays and the elucidation of their interactions with microtubule associated proteins

Micro/nano-structured titanium surfaces modified by NaOH–CaCl2-heat-water treatment: Biomimetic calcium phosphate deposition and hMSCs behavior

The unexplored effect of chemical treatment of laser micro/nanostructured titanium surfaces deserves attention due to broadening our knowledge of surface enhancement of biomimetic synthesis of hydroxyapatite and osseointegration of titanium implants. In this study, NaOH-CaCl2-heat-water treatment of titanium is revisited and used to modify porous laser micro/nanostructured oxidic and flat titanium surfaces which are characterized by XRD, electron microscopy, zeta potential and FTIR and Raman spectroscopy. These surfaces are also assessed for their ability to induce biomimetic Ca phosphate deposition from a simulated body fluid (SBF) and to grow human Mesenchymal stem cells (hMSCs). The treatment of titanium surfaces is shown to involve unreported formation of crystalline CaCO3 and the related interpretation of physicochemical changes of the treated titanium surface in soaked SBF raises doubts about the specific role of an intermediary CaTiO3 in the biomimetic formation of apatite on titanium substrates. We show that the biomimetic formation of Ca phosphate in Tas SBF solution occurs both on the surface and in the bulk solution, it is enhanced on the structured surfaces and is affected by a Ca-O(Ti) layer originating on the pristine and chemical treated flat and micro/nanostructured topographies with different delays. These findings are confronted with the pilot results of in vitro analyses showing that the cell growth, shape and osteogenic differentiation of hMSCs are impeded on the surfaces modified by the NaOH-CaCl2-heat-water treatment

Korozní chování povrchu silicidu titanu v přítomnosti peroxidu vodíku: Tvorba sub-μm kuliček na bázi TiOx, nanokompozitních fází TiOx / SiOx a mezoporézní sítě TiOx / SiOx

Dosud neprozkoumaná koroze povrchu silicidu titanu (Ti5Si3) okyseleným peroxidem vodíku je zajímavá díky svému potenciálnímu využití při zlepšování osseointegrace titanových implantátů potažených silicidy titanu. Detailní charakterizace produktů koroze pomocí FTIR, Ramanovy a XP spektroskopie, elektronové mikroskopie, XRD, BET a techniky rozptylu světla umožňují rozpoznání hydratovaných nanokompozitních fází TiOx / SiOx (x≤2) složených ze segregovaných amorfních fází SiOx a sítě na bázi TiOx obsahující vazby Ti-O-Si a -O-O. ¨ Vzhled TiOx síťoví závisí na rozsahu peroxidace. Méně postupující peroxidace poskytuje submikronové kuličky na bázi Tild, které po žíhání vyvíjejí anatasová nahozena, která odolávají do teploty 800 °C. Výraznější peroxidace produkuje větší mesoporézní tělíska na bázi TiOx, která se desintegrují po působení ultrazvuku na entity o velikosti mikrometrů. Navrhovaný mechanismus povrchové koroze vyplývá z komplementárního použití analytických technik. Jednokroková produkce bioaktivních (hydratovaných TiOx a SiOx) druhů je vhodná pro další výzkum osseointegrace mírně zkorodovaných titanových implantátů potažených Ti5Si3.silicid titanu, peroxid vodíku, mikrofáze SiOx, nanofáze TiOx a SiOx, mezoporézní a mikroporézní částice na bázi TiOxSo far unexplored corrosion of titanium silicide (Ti5Si3) surface with acidified hydrogen peroxide is of interest due to its potential use in improving osseointegration of titanium implants coated by titanium silicides. Detailed examination of corrosion products by FTIR, Raman and XP spectroscopy, electron microscopy, XRD, BET and light scattering techniques allows recognition of hydrated nanocomposite TiOx/SiOx (x≤2) phases composed of segregated amorphous SiOx species and TiOx–based networks containing Ti-O-Si and -O-O- bonds. The appearance of the TiOx networks depends on the extent of peroxidation. A less progressed peroxidation yields sub- μm-sized TiOx-based spheres which upon annealing develop anatase nanograins withstanding 800° C. A more progressed peroxidation produces larger mesoporous TiOx-based bodies which disintegrate upon sonication into micrometer-sized entities. The proposed mechanism of surface corrosion is based on the complementary use of analytical techniques. The one-step production of bioactive (hydrated TiOx and SiOx) species deserves to be explored in osseointegration studies of slightly corroded Ti5Si3-coated titanium implants