transmission electron microscopy (TEM) Dotaz Zobrazit nápovědu
Autoři vyšetřili transmisní elektronovou mikroskopii (TEM) vekou submakulární neovaskulární membránu, která klinicky imitovala nitrooční nádor. TEM byly ve vzorku nalezeny fibroblasty, pigmentové buňky sítnice, části světločivých buněk, krevní výron a vazivová tkáň.
The authors examined by transmission electron mycroscopy (TEM) a large submacular neovascular membrane which imitated clinically an intraocular tumour. TEM revealed in the sample fibroblast, pigmented retinal cells, parts of light-sensitive cells, a haematoma and connective tissue.
- MeSH
- dospělí MeSH
- elektronová mikroskopie MeSH
- epiretinální membrána MeSH
- krvácení do sklivce ultrasonografie MeSH
- laserová koagulace MeSH
- lidé MeSH
- makulární degenerace patologie MeSH
- neovaskularizace sítnice MeSH
- senioři MeSH
- vitrektomie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mužské pohlaví MeSH
- senioři MeSH
- Publikační typ
- kazuistiky MeSH
Scanning and transmission electron microscopy (TEM) were used to study the histopathological effects of the monogenean Macrogyrodactylus clarii Gussev, 1961 on the gills of the catfish Clarias gariepinus (Burchell). Suction generated during attachment created 'footprints' on host surfaces in which the host tissues were elevated above the general gill surface. 'Footprints' were bordered by four clefts caused by the muscular flaps on the anterior, lateral and posterior margins of the haptor. The hamuli points penetrate the gill tissue but no evidence was found for the insertion of the marginal hooklets. At the site of attachment, host cells adjacent to the lateral flaps often appeared compressed and widely spaced with large intercellular spaces. Desquamation of these surface epithelia was also apparent and some of the widely spaced epithelial cells had pseudopodium-like processes. Cells within the upper surface epithelial layer of the host were vacuolated and necrotic. Ruptured blood capillaries (blood spaces) in the secondary gill lamellae contained atypical compressed erythrocytes, agranular and granular leucocytes and evidence of haemorrhaging. Cells with fibrotic cytoplasm, putative phagocytes and host mucous cells were evidence of a host response at the site of parasite attachment. The possible role of these cells is discussed in relation to host resistance against infection.
- MeSH
- infekce červy třídy Trematoda parazitologie patologie MeSH
- mikroskopie elektronová rastrovací MeSH
- nemoci ryb parazitologie patologie MeSH
- sumci parazitologie MeSH
- transmisní elektronová mikroskopie MeSH
- Trematoda ultrastruktura MeSH
- žábry patologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Diabetic cystoid macular oedema (DME) is a common cause of visual acuity decrease. Good anatomical results and visual acuity (VA) of pars plana vitrectomy (PPV) in a case of a macular hole with internal limiting membrane peeling leads to the use of this technique in DME. A favourable result even in a case without vitreoretinal traction leads to the conclusion that pathogenesis of this disease is different. We analysed retrospectively 20 eyes from 20 patients with DME that had undergone PPV and peeling ILM. Half of them were laser treated before surgery. All eyes had an attached posterior hyaloid membrane in the macular region, but without thickening and without traction. We examined parts of excised tissues by transmission electron microscopy (TEM). Median duration of DME at the time of PPV was approximately 18.0 months (range 12 – 24 months). The median preoperative best corrected VA of 0.4 (range 0, 01–1, 0), improved to a median postoperative VA of 0.55 (range 0, 01–1, 0). Ten eyes without preoperative laser coagulation had a median VA improvement of 112 %, while 10 eyes with preoperative focal macular laser treatment had a median VA improvement of 17 %. In all 20 eyes, DME was no longer visible on microscopic examination after a median period of 3.0 months after PPV. We classified TEM samples containing ILM, glial cells and connective tissue as monolayer membrane, multilayer membrane, and true epimacular fibrous membrane. PPV and peeling ILM resulted in the resolution of oedema, with an improvement in visual acuity in the majority of cases. Eyes without preoperative macular photocoagulation had a significantly higher visual improvement than eyes with preoperative laser treatment, but PPV had an additive effect on final visual acuity in focal laser treated eyes. A randomised controlled prospective trial of PPV versus laser is needed to determine the role of PPV as a treatment modality for DME.
- MeSH
- diabetická retinopatie diagnóza komplikace terapie MeSH
- financování organizované MeSH
- komplikace diabetu diagnóza etiologie terapie MeSH
- lidé MeSH
- makulární edém diagnóza etiologie MeSH
- mikroskopie elektronová rastrovací transmisní metody využití MeSH
- prospektivní studie MeSH
- statistika jako téma metody MeSH
- vitrektomie metody přístrojové vybavení využití MeSH
- Check Tag
- lidé MeSH
Autoři vyšetřili transmisní elektronovou mikroskopií pupilární membránu u neovaskulárního glaukomu. Membrána byla tvořena vazivem, ve kterém převažovaly fibroblasty, pigmentové buňky a kolagenní vlákna. Vysoký obsah buněk svědčil pro vysokou metabolickou a růstovou aktivitu.
The authors examined using transmission electron microscopy the pupillary membrane in neovascular glaucoma. The membrane was formed by connective tissue where fibroblasts, pigmentcells andcollagenfibres predominated. Thehigh cell content suggested a high metabolic and growth activity.
Quantitation of viruses is practised widely in both basic and applied virology. Infectious titration in cell cultures, the most common approach to it, is quite labour-intensive and alternative protocols are therefore sought. One of the alternatives is transmission electron microscope (TEM) quantitation using latex particles at a known concentration as a reference for counting virus particles. If virus TCID₅₀ is determined in parallel, the ratio of infectious to non-infectious virus particles may be established. This study employs such an approach to compute the number of virus particles and TCID₅₀, and establish their correlation for three viruses: Canine adenovirus 1 (CAdV-1), Feline calicivirus (FCV) and Bovine herpesvirus 1 (BoHV-1). Each of the viruses was grown in five replicates until complete cytopathology was recorded (time 0), then frozen. They were thawed, filter-sterilised and left for additional periods of 16, 32 and 48 h at 37°C. At each time point, the infectious ability of the virus was characterised by TCID50 and the number of virions quantified by TEM, in order to evaluate the influence of timing on virus harvest. The virus particle count determined by TEM did not change for any of the viruses throughout the experiment. The relationship between virus particle counts with TCID₅₀ at time 0 showed good linearity response; their ratio was almost constant. The virus particle-to-TCID₅₀ ratio varied between 146 and 426 (mean±SD: 282±103) for CAdV-1, between 36 and 79 (57±18) for FCV and between 110 and 249 (167±53) for BoHV-1. The proportion of non-infectious particles did not change throughout the experiment for either CAdV-1 or BoHV-1. However, a decrease in virus infectious ability disclosed by TCID₅₀ indicated that the fraction of non-infectious particles in FCV increased 300,000 times when time 0 and 48 h were compared. The quantitation of viruses with TEM is a simple and rapid protocol for virus quantitation but account must be taken of the type of virus and harvesting time as virus counts need not necessarily correlate with virus infectious ability.
- MeSH
- bovinní herpesvirus 1 izolace a purifikace fyziologie MeSH
- buněčné linie MeSH
- časové faktory MeSH
- kočičí kalicivirus izolace a purifikace fyziologie MeSH
- kultivace virů MeSH
- mikrobiální viabilita * MeSH
- psí adenoviry izolace a purifikace fyziologie MeSH
- transmisní elektronová mikroskopie metody MeSH
- virová nálož metody MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Extracellular vesicles (EVs) function as important conveyers of information between cells and thus can be exploited as drug delivery systems or disease biomarkers. Transmission electron microscopy (TEM) remains the gold standard method for visualisation of EVs, however the analysis of individual EVs in TEM images is time-consuming if performed manually. Therefore, we present here a software tool for computer-assisted evaluation of EVs in TEM images. TEM ExosomeAnalyzer detects EVs based on their shape and edge contrast criteria and subsequently analyses their size and roundness. The software tool is compatible with common negative staining protocols and isolation methods used in the field of EV research; even with challenging TEM images (EVs both lighter and darker than the background, images containing artefacts or precipitated stain, etc.). If the fully-automatic analysis fails to produce correct results, users can promptly adjust the detected seeds of EVs as well as their boundaries manually. The performance of our tool was evaluated for three different modes with variable levels of human interaction, using two datasets with various heterogeneity. The semi-automatic mode analyses EVs with high success rate in the homogenous dataset (F1 score 0.9094, Jaccard coefficient 0.8218) as well as in the highly heterogeneous dataset containing EVs isolated from cell culture medium and patient samples (F1 score 0.7619, Jaccard coefficient 0.7553). Moreover, the extracted size distribution profiles of EVs isolated from malignant ascites of ovarian cancer patients overlap with those derived by cryo-EM and are comparable to NTA- and TRPS-derived data. In summary, TEM ExosomeAnalyzer is an easy-to-use software tool for evaluation of many types of vesicular microparticles and is available at http://cbia.fi.muni.cz/exosome-analyzer free of charge for non-commercial and research purposes. The web page contains also detailed description how to use the software tool including a video tutorial.
- Publikační typ
- časopisecké články MeSH
The Pithoviridae giant virus family exhibits the largest viral particle known so far, a prolate spheroid up to 2.5 μm in length and 0.9 μm in diameter. These particles show significant variations in size. Little is known about the structure of the intact virion due to technical limitations with conventional electron cryo-microscopy (cryo-EM) when imaging thick specimens. Here we present the intact structure of the giant Pithovirus sibericum particle at near native conditions using high-voltage electron cryo-tomography (cryo-ET) and energy-filtered cryo-EM. We detected a previously undescribed low-density outer layer covering the tegument and a periodical structuring of the fibres in the striated apical cork. Energy-filtered Zernike phase-contrast cryo-EM images show distinct substructures inside the particles, implicating an internal compartmentalisation. The density of the interior volume of Pithovirus particles is three quarters lower than that of the Mimivirus. However, it is remarkably high given that the 600 kbp Pithovirus genome is only half the size of the Mimivirus genome and is packaged in a volume up to 100 times larger. These observations suggest that the interior is densely packed with macromolecules in addition to the genomic nucleic acid.
Liposomes are used for in vitro or in vivo vectorization of drugs, proteins, or nucleic acids. However, the main problem with the application of liposomes for this purpose is their low stability in contact with blood serum. In this article, interactions between the whole serum and anionic liposomes, both bare and covered with strong polycations, were studied. The polycations of different chemical structures were prepared by the modification of poly(allylamine hydrochloride) (PAH). Dynamic light scattering (DLS), zeta potential and transmission cryo-electron microscopy (cryo-TEM) measurements showed that the adsorption of the polycations on the anionic liposomes induced a reversible aggregation of vesicles. The stable isolated polyelectrolyte-covered vesicles were obtained after the addition of sufficient amounts of the polycations. The effect of full serum on the morphology and stability of the polycation-coated liposomes was studied using cryo-TEM and a fluorescence method. The cryo-TEM analysis revealed that the introduction of serum caused the osmotic-driven destabilization of the bare liposomes or formation of twinned vesicles. Due to these processes the liposomes lost most of their content immediately after serum addition. The polycation-covered liposomes showed improved stability in the presence of serum. Partial deflation of the vesicles was observed, however, the loss of the content was significantly limited. The effect of the polymer structure, especially the position of the charged groups with respect to the main polymer backbone, on the stabilization of the polycation-covered liposomes in the presence of serum was discussed.
- MeSH
- elektrolyty chemie MeSH
- elektronová kryomikroskopie * MeSH
- fluoresceiny metabolismus MeSH
- fosfatidylcholiny chemie MeSH
- hydrodynamika MeSH
- liposomy chemie ultrastruktura MeSH
- polyaminy chemie MeSH
- polymery chemie MeSH
- sérum chemie MeSH
- skot MeSH
- statická elektřina MeSH
- tlak MeSH
- transmisní elektronová mikroskopie * MeSH
- zvířata MeSH
- Check Tag
- skot MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Cell culture methods have been developed in efforts to produce biologically relevant systems for developmental and disease modeling, and appropriate analytical tools are essential. Knowledge of ultrastructural characteristics represents the basis to reveal in situ the cellular morphology, cell-cell interactions, organelle distribution, niches in which cells reside, and many more. The traditional method for 3D visualization of ultrastructural components, serial sectioning using transmission electron microscopy (TEM), is very labor-intensive due to contentious TEM slice preparation and subsequent image processing of the whole collection. In this chapter, we present serial block-face scanning electron microscopy, together with complex methodology for spheroid formation, contrasting of cellular compartments, image processing, and 3D visualization. The described technique is effective for detailed morphological analysis of stem cell spheroids, organoids, as well as organotypic cell cultures.
