The increasing incidence of trauma in medicine brings with it new demands on the materials used for the surgical treatment of bone fractures. Titanium, its alloys, and steel are used worldwide in the treatment of skeletal injuries. These metallic materials, although inert, are often removed after the injured bone has healed. The second-stage procedure-the removal of the plates and screws-can overwhelm patients and overload healthcare systems. The development of suitable absorbable metallic materials would help us to overcome these issues. In this experimental study, we analyzed an extruded Zn-0.8Mg-0.2Sr (wt.%) alloy on a rabbit model. From this alloy we developed screws which were implanted into the rabbit tibia. After 120, 240, and 360 days, we tested the toxicity at the site of implantation and also within the vital organs: the liver, kidneys, and brain. The results were compared with a control group, implanted with a Ti-based screw and sacrificed after 360 days. The samples were analyzed using X-ray, micro-CT, and a scanning electron microscope. Chemical analysis revealed only small concentrations of zinc, strontium, and magnesium in the liver, kidneys, and brain. Histologically, the alloy was verified to possess very good biocompatibility after 360 days, without any signs of toxicity at the site of implantation. We did not observe raised levels of Sr, Zn, or Mg in any of the vital organs when compared with the Ti group at 360 days. The material was found to slowly degrade in vivo, forming solid corrosion products on its surface.

• Klíčová slova
• absorbable metals, alloy accumulation, biocompatibility, in vivo, internal organs, magnesium, strontium, systemic reactions, toxicity, zinc,
• MeSH
• fraktury tibie * metabolismus   chirurgie   MeSH
• hořčík chemie   farmakokinetika   farmakologie   MeSH
• králíci MeSH
• lidé MeSH
• slitiny * chemie   farmakokinetika   farmakologie   MeSH
• stroncium chemie   farmakokinetika   farmakologie   MeSH
• testování materiálů * MeSH
• tibie metabolismus   patologie   MeSH
• vstřebatelné implantáty * MeSH
• zinek chemie   farmakokinetika   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hořčík MeSH
• slitiny * MeSH
• stroncium MeSH
• zinek MeSH

Degradable zinc-based alloys with an appropriate corrosion rate are promising materials for the preparation of temporary orthopaedic implants. Previously, we prepared and characterised a novel Zn1.5Mg alloy. This paper is focused on the characterisation of this alloy after a surface pre-treatment, which should mimic processes occurring in vivo. The samples of the Zn1.5Mg alloy were immersed in a simulated body fluid (SBF) at 37°C for 14days in order to form a protective layer of corrosion products. Thereafter, these samples were used for the corrosion rate determination, an indirect in vitro cytotoxicity test, as well as for a direct contact test and were compared with the non-treated samples. The protective layer was characterized by SEM and its chemical composition was determined by EDS and XPS analysis. The corrosion rate was significantly decreased after the pre-incubation. The protective layer of corrosion products was rich in Ca and P. The pre-incubated samples exhibited increased cytocompatibility in the indirect test (metabolic activity of L929 cells was above 70%) and we also observed osteoblast-like cell growth directly on the samples during the contact tests. Thus, the pre-incubation in SBF leading to improved cytocompatibility could represent more appropriate model to in vivo testing.

• Klíčová slova
• Biodegradable alloys, Cytocompatibility, In vitro testing, Zinc,
• MeSH
• buněčné linie MeSH
• hořčík * chemie   farmakologie   MeSH
• koroze MeSH
• myši MeSH
• osteoblasty cytologie   metabolismus   MeSH
• slitiny * chemie   farmakologie   MeSH
• tělesné tekutiny chemie   MeSH
• testování materiálů * MeSH
• viabilita buněk účinky léků   MeSH
• vstřebatelné implantáty * MeSH
• zinek * chemie   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hořčík * MeSH
• slitiny * MeSH
• zinek * MeSH

We investigated fungal growth and community composition in buried meshbags, amended with apatite, biotite or hornblende, in Norway spruce (Picea abies) forests of varying nutrient status. Norway spruce needles and soil collected from forests overlying serpentinite had low levels of potassium and phosphorus, those from granite had low levels of magnesium, whereas those from amphibolite had comparably high levels of these nutrients. We assayed the fungal colonization of meshbags by measuring ergosterol content and fungal community with 454 sequencing of the internal transcribed spacer region. In addition, we measured fine root density. Fungal biomass was increased by apatite amendment across all plots and particularly on the K- and P-deficient serpentinite plots, whereas hornblende and biotite had no effect on fungal biomass on any plots. Fungal community (total fungal and ectomycorrhizal) composition was affected strongly by sampling location and soil depth, whereas mineral amendments had no effect on community composition. Fine root biomass was significantly correlated with fungal biomass. Ectomycorrhizal communities may respond to increased host-tree phosphorus demand by increased colonization of phosphorus-containing minerals, but this does not appear to translate to a shift in ectomycorrhizal community composition. This growth response to nutrient demand does not appear to exist for potassium or magnesium limitation.

• Klíčová slova
• Norway spruce (Picea abies), ectomycorrhizal fungi (EMF), ergosterol, fungal community composition, hyphae, minerals, soil nutrients,
• MeSH
• biomasa MeSH
• draslík farmakologie   MeSH
• ergosterol metabolismus   MeSH
• fosfor farmakologie   MeSH
• hořčík farmakologie   MeSH
• houby účinky léků   růst a vývoj   MeSH
• lesy * MeSH
• listy rostlin chemie   účinky léků   MeSH
• minerály metabolismus   MeSH
• multivariační analýza MeSH
• půdní mikrobiologie * MeSH
• smrk účinky léků   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• ergosterol MeSH
• fosfor MeSH
• hořčík MeSH
• minerály MeSH

This study deals with the use of cationic far-red absorbing photosensitizers (λ(max) ~740 nm) from the group of the phthalocyanines, in photodynamic therapy. The photosensitizers differed in their central atom, bearing either hydrogen, zinc or magnesium. These photosensitizers were tested in vitro on the tumour cell line HeLa (cervical cancer) and non-tumour cell line NIH3T3 (mouse fibroblast). The following tests were performed: measurement of reactive oxygen species production, viability testing, Comet assay and cell type detection (apoptotic, necrotic and living cells). The best results were achieved with zinc derivative at relatively low half-maximum inhibitory concentration (0.04 μM) and a total radiation dose of 15 J cm(-2).

• Klíčová slova
• Photosensitizer, Phthalocyanine, cellular damage, oxidative stress, photodynamic treatment, phototoxicity, tumour cells,
• MeSH
• buněčné linie MeSH
• buňky NIH 3T3 MeSH
• fotochemoterapie metody   MeSH
• fotosenzibilizující látky farmakologie   MeSH
• HeLa buňky MeSH
• hořčík farmakologie   MeSH
• indoly farmakologie   MeSH
• isoindoly MeSH
• lidé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádory farmakoterapie   metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• zinek farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• fotosenzibilizující látky MeSH
• hořčík MeSH
• indoly MeSH
• isoindoly MeSH
• phthalocyanine MeSH Prohlížeč
• reaktivní formy kyslíku MeSH
• zinek MeSH

Novel zinc, magnesium, and metal-free octasubstituted phthalocyanine photosensitizers bearing [(triethylammonio)ethyl]sulfanyl substituents in the peripheral or nonperipheral positions were synthesized and investigated for their photophysical properties (ΦΔ value up to 0.91, λmax up to 750 nm) and photodynamic anticancer activity. The photodynamic treatment of 3T3, HeLa, SK-MEL-28, and HCT 116 cancer cells revealed that the magnesium complexes were not active (IC50 > 100 μM), whereas the IC50 values of the zinc complexes typically reached values in the submicromolar range with low toxicity in the dark (TC50 ≈ 1500 μM). The subcellular changes upon photodynamic treatment of the HeLa cells indicated that the studied photosensitizers induced damage primarily to the lysosomes, which was followed by a relocalization and damage to other organelles. The time-lapse morphological changes along with the flow cytometry and caspase activity measurements indicated a predominant involvement of necrosis-like cell death.

• MeSH
• absorpce radiace MeSH
• antitumorózní látky chemická syntéza   chemie   farmakologie   MeSH
• buněčná smrt účinky léků   MeSH
• buňky 3T3 MeSH
• fotochemoterapie * MeSH
• fotosenzibilizující látky chemická syntéza   chemie   farmakologie   MeSH
• HCT116 buňky MeSH
• HeLa buňky MeSH
• hořčík chemie   farmakologie   MeSH
• indoly chemická syntéza   chemie   farmakologie   MeSH
• isoindoly MeSH
• léky antitumorózní - screeningové testy MeSH
• lidé MeSH
• molekulární struktura MeSH
• myši MeSH
• organokovové sloučeniny chemická syntéza   chemie   farmakologie   MeSH
• proliferace buněk účinky léků   MeSH
• světlo MeSH
• viabilita buněk účinky léků   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zinek chemie   farmakologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antitumorózní látky MeSH
• fotosenzibilizující látky MeSH
• hořčík MeSH
• indoly MeSH
• isoindoly MeSH
• organokovové sloučeniny MeSH
• phthalocyanine MeSH Prohlížeč
• zinek MeSH

The aim of this study was to investigate the response of Russian sturgeon (Acipenser gueldenstaedtii) sperm to external cations (Na(+), K(+), Ca(2+), and Mg(2+)) and their susceptibility on the induction of motility and swimming behavior. An in vitro spermatozoa motility assay was used by a computer-aided Motion-Analysis system. Sperm motility was inhibited by 60 mM NaCl (~140 mOsm/kg) and 0.7 mM KCl solutions (~ 21.4 mOsm/kg). The Ca(2+) and Mg(2+) ions were not able to inhibit spermatozoa motility. By contrast, Na(+) within a limited concentration range (between 45 and 55 mm) was able to reverse the inhibitory effect of K(+) at the critical concentration (0.7 mM). Ca(2+) and Mg(2+) were also able to reverse the K(+)-mediated spermatozoa motility restriction at concentrations starting at 0.01 and 0.1 mM, respectively. These results provide evidence for the role of K(+) in suppressing spermatozoa motility, and suggest that Ca(2+), Mg(2+), and possibly Na(+) trigger motility in Russian sturgeon sperm.

• MeSH
• analýza spermatu MeSH
• draslík farmakologie   MeSH
• hořčík farmakologie   MeSH
• kationty farmakologie   MeSH
• motilita spermií účinky léků   MeSH
• osmolární koncentrace MeSH
• plavání MeSH
• ryby * fyziologie   MeSH
• sodík farmakologie   MeSH
• spermie účinky léků   fyziologie   MeSH
• vápník farmakologie   MeSH
• vodní hospodářství MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• hodnotící studie MeSH
• práce podpořená grantem MeSH
• Názvy látek
• draslík MeSH
• hořčík MeSH
• kationty MeSH
• sodík MeSH
• vápník MeSH

We used NADPH-diaphorase staining to study effects of magnesium pre-treatment during long-lasting hypoxia on the brain structure of rats. NADPH-diaphorase is an enzyme co-localized in neurons with NO-synthase that is responsible for NO synthesis. NO participates in hypoxic-ischaemic injury of the brain. Hypoxia was induced in consecutive days from the 2nd till the 11th day of postnatal life in a hypobaric chamber (for 8 hours per day). Magnesium was administered before each hypoxia exposition. At the age of 12 days, the animals were transcardially perfused with 4% buffered neutral paraformaldehyde under the deep thiopental anaesthesia. Cryostat sections were stained to identify NADPH-diaphorase positive neurons that were then quantified in five hippocampal regions. In comparison to the control animals, intermittent hypoxia brought about higher density of NADPH-diaphorase positive neurons in all studied areas of the hippocampal structure: in CA1 and CA3 areas of the hippocampus and in hilus, in the dorsal and ventral blades of the dentate gyrus. Magnesium pre-treatment during hypoxia reduced number of NADPH-diaphorase positive neurons in all studied areas.

• MeSH
• hipokampus účinky léků   metabolismus   MeSH
• hořčík farmakologie   MeSH
• hypoxie metabolismus   MeSH
• krysa rodu Rattus MeSH
• NADPH-dehydrogenasa metabolismus   MeSH
• neurony metabolismus   MeSH
• oxid dusnatý metabolismus   MeSH
• potkani Wistar MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• hořčík MeSH
• NADPH-dehydrogenasa MeSH
• oxid dusnatý MeSH

A set of single-tryptophan mutants of the Na(+)/K(+)-ATPase isolated, large cytoplasmic loop connecting transmembrane helices M4 and M5 (C45) was prepared to monitor effects of the natural cytoplasmic ligands (i.e., Mg(2+) and/or ATP) binding. We introduced a novel method for the monitoring of the changes in the electrostatic surface potential (ESP) induced by ligand binding, using the quenching of the intrinsic tryptophan fluorescence by acrylamide or iodide. This approach opens a new way to understanding the interactions within the proteins. Our experiments revealed that the C45 conformation in the presence of the ATP (without magnesium) substantially differed from the conformation in the presence of Mg(2+) or MgATP or in the absence of any ligand not only in the sense of geometry but also in the sense of the ESP. Notably, the set of ESP-sensitive residues was different from the set of geometry-sensitive residues. Moreover, our data indicate that the effect of the ligand binding is not restricted only to the close environment of the binding site and that the information is in fact transmitted also to the distal parts of the molecule. This property could be important for the communication between the cytoplasmic headpiece and the cation binding sites located within the transmembrane domain.

• MeSH
• adenosintrifosfát metabolismus   farmakologie   MeSH
• akrylamid metabolismus   farmakologie   MeSH
• cytoplazma metabolismus   MeSH
• fluorescence MeSH
• hořčík metabolismus   farmakologie   MeSH
• jodidy metabolismus   farmakologie   MeSH
• konformace proteinů účinky léků   MeSH
• ligandy MeSH
• molekulární modely MeSH
• mutace MeSH
• myši MeSH
• povrchové vlastnosti MeSH
• sodíko-draslíková ATPasa chemie   genetika   metabolismus   MeSH
• statická elektřina * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosintrifosfát MeSH
• akrylamid MeSH
• hořčík MeSH
• jodidy MeSH
• ligandy MeSH
• sodíko-draslíková ATPasa MeSH

Conformational changes of the Na(+)/K(+)-ATPase isolated large cytoplasmic segment connecting transmembrane helices M4 and M5 (C45) induced by the interaction with enzyme ligands (i.e. Mg(2+) and/or ATP) were investigated by means of the intrinsic tryptophan fluorescence measurement and molecular dynamic simulations. Our data revealed that this model system consisting of only two domains retained the ability to adopt open or closed conformation, i.e. behavior, which is expected from the crystal structures of relative Ca(2+)-ATPase from sarco(endo)plasmic reticulum for the corresponding part of the entire enzyme. Our data revealed that the C45 is found in the closed conformation in the absence of any ligand, in the presence of Mg(2+) only, or in the simultaneous presence of Mg(2+) and ATP. Binding of the ATP alone (i.e. in the absence of Mg(2+)) induced open conformation of the C45. The fact that the transmembrane part of the enzyme was absent in our experiments suggested that the observed conformational changes are consequences only of the interaction with ATP or Mg(2+) and may not be related to the transported cations binding/release, as generally believed. Our data are consistent with the model, where ATP binding to the low-affinity site induces conformational change of the cytoplasmic part of the enzyme, traditionally attributed to E2-->E1 transition, and subsequent Mg(2+) binding to the enzyme-ATP complex induces in turn conformational change traditionally attributed to E1-->E2 transition.

• MeSH
• adenosintrifosfát metabolismus   farmakologie   MeSH
• biofyzikální jevy MeSH
• biologické modely MeSH
• DNA primery genetika   MeSH
• fluorescenční polarizace MeSH
• fluorescenční spektrometrie MeSH
• hořčík metabolismus   farmakologie   MeSH
• konformace proteinů účinky léků   MeSH
• molekulární modely MeSH
• mutageneze cílená MeSH
• myši MeSH
• peptidové fragmenty chemie   genetika   metabolismus   MeSH
• rekombinantní proteiny chemie   genetika   metabolismus   MeSH
• sekvence nukleotidů MeSH
• sodíko-draslíková ATPasa chemie   genetika   metabolismus   MeSH
• substituce aminokyselin MeSH
• techniky in vitro MeSH
• termodynamika MeSH
• tryptofan chemie   MeSH
• vazebná místa MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• adenosintrifosfát MeSH
• DNA primery MeSH
• hořčík MeSH
• peptidové fragmenty MeSH
• rekombinantní proteiny MeSH
• sodíko-draslíková ATPasa MeSH
• tryptofan MeSH

Influence of magnesium pre-treatment during repetitive hypoxia was studied in the hippocampus of rats by histochemical analysis (NADPH-diaphorase staining). NADPH-diaphorase occurs concurrently with NO-synthase that is responsible for NO synthesis. Rat pups were kept together with their mother for 8 hours a day in a hypobaric chamber at a simulated altitude of 7,000 m since the day of birth till the 17th day. The first group of animals was exposed to the repeated hypoxia; the second group under the same conditions was pre-treated by magnesium before the exposition to the hypoxia. Both groups were compared with intact control animals and intact animals treated with magnesium. The experimental and control animals were the transaortically perfused with 4% buffered neutral formaldehyde under thiopental anaesthesia at the age of 35 days. Brains were processed for NADPH-d staining. We estimated the density of NADPH-d positive neurons in CA1 and CA3 areas of the hippocampus and in the dentate gyrus. Intermittent hypoxia brings about higher numbers of NADPH-diaphorase positive neurons of CA1 and CA3 of the hippocampus and of the dorsal blade of dentate gyrus, in the comparison with either group of control animals. In the hilus and ventral blade of the dentate gyrus, on the contrary, the number of NADPH-d positive neurons was smaller. Magnesium pre-treatment during hypoxia decreased number of nitrergic neurons in all areas of the hippocampus except CA1 area, where the effect of magnesium was not significant. These results demonstrate that magnesium can probably have a neuroprotective effect.

• MeSH
• hipokampus cytologie   účinky léků   metabolismus   MeSH
• hořčík farmakologie   MeSH
• krysa rodu Rattus MeSH
• mozková hypoxie metabolismus   patologie   MeSH
• NADPH-dehydrogenasa metabolismus   MeSH
• potkani Wistar MeSH
• synthasa oxidu dusnatého metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• hořčík MeSH
• NADPH-dehydrogenasa MeSH
• synthasa oxidu dusnatého MeSH