hollow structure
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Here we provide a review on TldD/TldE family proteins, summarizing current knowledge and outlining further research perspectives. Despite being widely distributed in bacteria and archaea, TldD/TldE proteins have been escaping attention for a long time until several recent reports pointed to their unique features. Specifically, TldD/TldE generally act as peptidases, though some of them turned out to be N-deacetylases. Biological function of TldD/TldE has been extensively described in bacterial specialized metabolism, in which they participate in the biosynthesis of lincosamide antibiotics (as N-deacetylases), and in the biosynthesis of ribosomally synthesized and post-translationally modified bioactive peptides (as peptidases). These enzymes possess special position in the relevant biosynthesis since they convert non-bioactive intermediates into bioactive metabolites. Further, based on a recent study of Escherichia coli TldD/TldE, these heterodimeric metallopeptidases possess a new protein fold exhibiting several structural features with no precedent in the Protein Data Bank. The most interesting ones are structural elements forming metal-containing active site on the inner surface of the catalytically active subunit TldD, in which substrates bind through β sheet interactions in the sequence-independent manner. It results in relaxed substrate specificity of TldD/TldE, which is counterbalanced by enclosing the active centre within the hollow core of the heterodimer and only appropriate substrates can entry through a narrow channel. Based on the published data, we hypothesize a yet unrecognized central metabolic function of TldD/TldE in the degradation of (partially) unfolded proteins, i.e., in protein quality control.
PURPOSE OF REVIEW: This review describes the latest advances in cell therapy, biomaterials and 3D bioprinting for the treatment of cardiovascular disease. RECENT FINDINGS: Cell therapies offer the greatest benefit for patients suffering from chronic ischemic and nonischemic cardiomyopathy. Rather than replacing lost cardiomyocytes, the effects of most cell therapies are mediated by paracrine signalling, mainly through the induction of angiogenesis and immunomodulation. Cell preconditioning, or genetic modifications are being studied to improve the outcomes. Biomaterials offer stand-alone benefits such as bioactive cues for cell survival, proliferation and differentiation, induction of vascularization or prevention of further cardiomyocyte death. They also provide mechanical support or electroconductivity, and can be used to deliver cells, growth factors or drugs to the injured site. Apart from classical biomaterial manufacturing techniques, 3D bioprinting offers greater spatial control over biomaterial deposition and higher resolution of the details, including hollow vessel-like structures. SUMMARY: Cell therapy induces mainly angiogenesis and immunomodulation. The ability to induce direct cardiomyocyte regeneration to replace the lost cardiomyocytes is, however, still missing until embryonic or induced pluripotent stem cell use becomes available. Cell therapy would benefit from combinatorial use with biomaterials, as these can prolong cell retention and survival, offer additional mechanical support and provide inherent bioactive cues. Biomaterials can also be used to deliver growth factors, drugs, and other molecules. 3D bioprinting is a high-resolution technique that has great potential in cardiac therapy.
- MeSH
- 3D tisk * MeSH
- biokompatibilní materiály MeSH
- bioprinting * MeSH
- kardiomyocyty MeSH
- lidé MeSH
- myokard MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Monogeneans rely on firm attachment to often flexible and uneven surfaces and are renowned for their effective posterior attachment structures in the form of adhesives, clamps, hamuli and suckers. Polystomatids do not secrete adhesives and do not have clamps. While only some have hamuli, all have suckers in the adult form. Three different types of haptoral suckers have been described based on basic morphology but have never been studied in depth. Using enzyme digestion and light (differential interference contrast), confocal and scanning electron microscopy, we examined representatives and propose four sucker types. Haptoral sucker Type I are symmetrical soft, flexible, cup- to disk-shaped suckers and are found in all polystomes infecting frogs and salamanders. Type II suckers are symmetrical soft, flexible, cup-shaped suckers with a hollow continuous skeletal ring and no other skeletal elements. They are found in species of Nanopolystoma Du Preez, Wilkinson et Huyse, 2008 infecting caecilians. Type III suckers are symmetrical firm, cup-shaped suckers with elaborate skeletal elements that contribute to a secure grip on the host tissue. This type of sucker is found in all polystomes infecting freshwater turtles and the common hippopotamus. Type IV suckers are asymmetrical with an elaborate series of long, thin sclerites with terminal spines or hooks. This type of sucker is only known from Concinnocotyla australensis (Reichenbach-Klinke, 1966) infecting the Australian lungfish. These different sucker types are crucial for the survival of polystomatid flatworms within their respective microhabitats.
- MeSH
- mikroskopie elektronová rastrovací MeSH
- Trematoda * anatomie a histologie klasifikace MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
... radio-ulnar joint 118 -- Architecture and mechanical features of the distal end of the ulna 118 -- Structure ... ... prehensile ability of the hand 200 -- The architecture of the hand 204 -- The carpus 208 -- The hollowing ... ... movements of M1 272 -- Radiographic features of the TM joint and of the trapezial system 274 -- The structural ...
Seventh edition xiii, 367stran, 2 nečíslované listy obrazové přílohy : ilustrace ; 28 cm
Polyacrylonitrile (PAN) membranes have been prepared using needleless electrospinning with wire electrode and characterized by a series of methods HRSEM, XRD, air permeability and area weight measurements in dependence of high voltage and electrode distance. HRSEM analysis revealed the tendency to longitudinal rolling of strip-shaped PAN fibers forming hollow fibers. Combination of XRD analysis and molecular modeling explains this phenomenon as the consequence of the specific crystal structure of PAN fibers, where the isotactic PAN chains are arranged in layers forming belt shaped nanofibers with the strong tendency to roll up longitudinally forming hollow fibers. This effect offers the possibility to create hollow nanofibers by electrospinning with the appropriate choice of structure of polymer chains.
Úvod: Korozivní preparáty (KP) slouží k vizualizaci a hodnocení morfologie dutých struktur. KP s naplněným kapilárním řečištěm umožňují za pomoci zobrazovacích metod získání dat použitelných pro matematické modelování orgánové perfuze. Náročnost přípravy KP stoupá s objemem cévního řečiště, proto byly touto metodou doposud zkoumány zejména malé živočišné druhy. Cílem této studie bylo optimalizovat protokoly přípravy korozivních preparátů různých orgánů prasete domácího, a to vzhledem k dostupnosti těchto orgánů a významu prasete domácího v experimentální medicíně. Metoda: Byly použity orgány (játra, slezina, ledviny a tenké střevo) zdravého prasete domácího. Celkem 10 prasat (6 samic), plemeno přeštické černostrakaté, hmotnost 35–45 kg. Orgány byly vypreparovány, do systémového řečiště byl aplikován heparin a následně byl cévní systém orgánu propláchnut buď in situ (játra), nebo po vyjmutí z těla zvířete (ledviny, slezina, tenké střevo) heparinizovaným fyziologickým roztokem. Veškerá manipulace s vyjmutými orgány pak probíhala pod vodní hladinou z důvodu prevence embolizace vzduchu do cévního řečiště. Dalším krokem byla intraarteriální (u jater i intraportální) aplikace pryskyřice Biodur E20? (Heidelberg, Německo). Po ztuhnutí pryskyřice byly odstraněny okolní tkáně pomocí 15% roztoku KOH a poté vymyty vodou. Objemné preparáty byly uchovávány v 70% denaturovaném alkoholu, menší byly vysušeny mrazem. Hotové KP byly zkoumány pomocí stereomikroskopu, běžné výpočetní tomografie (CT), mikro-CT, skenovací elektronové mikroskopie (SEM) nebo vysokorozlišovacího digitálního mikroskopu. Výsledky: Díky odběru orgánů za specifických podmínek, použití vhodné pryskyřice i metodiky nástřiku se podařilo získat kvalitní KP jater, ledvin, sleziny a tenkého střeva prasete domácího. Možnost barvení pryskyřice zlepšila makroskopickou přehlednost preparátů. Bylo provedeno skenování pomocí běžného CT, které se ukázalo jako vhodná metoda pro zkoumání preparátu jater. Mikro-CT, SEM a vysokorozlišovací digitální mikroskopie pak přinesly obrazy nejdrobnějších struktur řečiště zkoumaných orgánů. I když se SEM pro kontrolu kvality odlitků ještě stále jeví jako nezastupitelná, zdá se, že může být částečně nahrazena vysokorozlišovacím digitálním mikroskopem. Mikro-CT umožnilo získání dat o prostorovém uspořádání řečiště a dat pro budoucí softwarové modelování orgánové perfuze zkoumaných orgánů. Vysoká kvalita získaných preparátů umožnila jejich využití i ve výuce anatomie člověka. Závěr: Podařilo se optimalizovat protokol přípravy KP jater, ledvin, sleziny a tenkého střeva prasete domácího. S použitím různých zobrazovacích modalit mohou být tyto KP využity pro získání dat o prostorové architektonice cévního řečiště. Tato data mohou být využita pro přípravu matematických modelů orgánové perfuze využitelných například pro optimalizaci orgánových resekcí.
Introduction: Corrosion casts (CCs) are used for the visualization and assessment of hollow structures. CCs with filled capillaries enable (with the help of imaging methods) to obtain data for mathematical organ perfusion modelling. As the processing is more difficult in case of organs with greater volume of the vasculature, mainly organs from small animals have been cast up to now. The aim of this study was to optimize the protocol of corrosion casting of different organs of pig. Porcine organs are relatively easily accessible and frequently used in experimental medicine. Method: Organs from 10 healthy Prestice Black-Pied pigs (6 females, body weight 35–45 kg), were used in this study (liver, spleen, kidneys and small intestine). The organs were dissected, heparin was administered into the systemic circulation and then the vascular bed of the organs was flushed with heparinized saline either in situ (liver) or after their removal (spleen, kidney, small intestine). All handling was done under the water surface to prevent air embolization. The next step was an intraarterial (in case of the liver also intraportal) administration of Biodur E20? (Heidelberg, Germany) resin. After hardening of the resin the organ tissue was dissolved by 15% KOH and the specimen was rinsed with tap water. Voluminous casts were stored in 70% denatured alcohol, the smaller ones were lyophilized. The casts were assessed with a stereomicroscope, computed and microcomputed tomography (CT and microCT), a scanning electron microscope (SEM) and high-resolution digital microscope (HRDM). Results: High-quality CCs of the porcine liver, kidneys, spleen and small intestine were created owing to the sophisticated organ harvesting, the suitable resin and casting procedure. Macroscopic clarity was improved thanks to the possibility of resin dying. Scanning by CT was performed and showed to be a suitable method for the liver cast examination. MicroCT, SEM and HRDM produced images of the most detailed structures of vascular bed. Despite the fact that SEM seems to be an irreplaceable method for CCs quality control, it seems that this modality could be partly replaced by HRDM. MicroCT enabled to obtain data about three-dimensional layout of the vascular bed and data for mathematical modelling of organ perfusion. With regard to the quality of the CCs, they could also be used to teach human anatomy. Conclusions: The protocol of the corrosion casting of the porcine liver, kidneys, spleen and small intestine CCs was optimized. Thanks to different imaging methods, the CCs can be used as a source of data on three-dimensional architecture of the vascular bed. These data can be used for mathematical modeling of organ perfusion which can be helpful for example for optimization of organ resections.
- Klíčová slova
- korozivní preparáty, Biodur E20,
- MeSH
- anatomické modely MeSH
- kapiláry MeSH
- modely u zvířat * MeSH
- prasata MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
Recently, porous carriers are used in the pharmaceuti-cal technology due to their promising properties ‒ large specific surface area, porous structure, suitable technologi-cal properties, etc. They participate in the preparation of liquisolid systems, self-emulsifying drug delivery systems, etc., which are capable to deliver and release the drug in the required manner to the biological system. One of the most widely used porous carrier is microcrystalline cellu-lose. Other perspective carriers are magnesium alumi-nometasilicates, which show several advantageous proper-ties. Also calcium hydrogen phosphate represents a com-monly used carrier with easy compressibility, rapid disin-tegration or improved flow properties. Due to their large specific surface area, mesoporous silicates and silica aero-gels are also often used. The clay materials in the form of natural or modified materials with a structure of hollow nanotubes provide a suitable carrier of the drug. This arti-cle summarizes basic information about available porous carriers and their characterizations, as well as available application studies on the given topic.
This work is focused on preparation of novel porous type of core-shell-structured microparticles based on polylactide (shell) and poly(vinyl alcohol) cross-linked with glutaric acid (GA) (core) prepared by water-in-oil-in-water solvent evaporation technique. The microparticle systems were used as delivery systems for immobilisation of model antibacterial agent - nisin. The effect of cross-linking and the initial amount of nisin on their morphology was investigated using scanning electron microscopy, BET analysis, zeta potential measurement and Fourier transform infra-red spectroscopy. Encapsulation efficiency and release profile of nisin from the microparticles were studied by high performance liquid chromatography. Antibacterial activity of the prepared systems was tested by dilution and spread plate technique. Results showed the microparticles in the size range of 9-16 μm in diameter with spherical multi-hollow core-shell structure. The presence of cross-linking agent GA influences the release profile of the peptide and has synergistic effect on Listeria monocytogenes growth reduction.
- MeSH
- antibakteriální látky aplikace a dávkování MeSH
- glutaráty chemie MeSH
- Listeria monocytogenes účinky léků MeSH
- mikroskopie elektronová rastrovací MeSH
- nisin aplikace a dávkování MeSH
- nosiče léků chemie MeSH
- polyestery chemie MeSH
- polyvinylalkohol chemie MeSH
- poréznost MeSH
- velikost částic MeSH
- Publikační typ
- časopisecké články MeSH
In teaching and learning human anatomy, anatomical autopsy and prosected specimens have always been indispensable. However, alternative methods must often be used to demonstrate particularly delicate structures. Corrosion casting of porcine organs with Biodur E20® Plus is valuable for teaching and learning both gross anatomy and, uniquely, the micromorphology of cardiovascular, respiratory, digestive, and urogenital systems. Assessments of casts with a stereomicroscope and/or scanning electron microscope as well as highlighting cast structures using color coding help students to better understand how the structures that they have observed as two-dimensional images actually exist in three dimensions, and students found using the casts to be highly effective in their learning. Reconstructions of cast hollow structures from (micro-)computed tomography scans and videos facilitate detailed analyses of branching patterns and spatial arrangements in cast structures, aid in the understanding of clinically relevant structures and provide innovative visual aids. The casting protocol and teaching manual we offer can be adjusted to different technical capabilities and might also be found useful for veterinary or other biological science classes.
- MeSH
- anatomické modely * MeSH
- anatomie výchova MeSH
- audiovizuální pomůcky MeSH
- cévy anatomie a histologie MeSH
- kapiláry anatomie a histologie MeSH
- korozní odlévání metody MeSH
- mikroskopie elektronová rastrovací MeSH
- mikroskopie MeSH
- postoj MeSH
- prasata anatomie a histologie MeSH
- studenti MeSH
- Sus scrofa anatomie a histologie MeSH
- vyučování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
... Molecules, and Systems 439 -- Visualizing Cells 529 -- INTERNAL ORGANIZATION OF THE CELL 565 -- Membrane Structure ... ... of Complex Biological -- Structures 130 -- Amyloid Fibrils Can Form from Many Proteins 130 -- Amyloid ... ... Structures Can Perform Useful Functions in Cells 132 -- Many Proteins Contain Low-complexity Domains ... ... tin Structures Are Important for Eukaryotic Chromosome -jnction -- SLOBAL STRUCTURE OF CHROMOSOMES - ... ... 461 -- Protein Sequence and Structure Provide Clues About Protein -- Function 462 -- Summary 463 -- ...
Sixth edition xxxiv, 1430 stran v různém stránkování : ilustrace (převážně barevné) ; 29 cm
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- molekulární biologie, molekulární medicína
- NLK Publikační typ
- učebnice vysokých škol
