• Klíčová slova
• cell image synthesis, deep learning, generative adversarial networks, style transfer,
• MeSH
• deep learning * MeSH
• neuronové sítě MeSH
• počítačové zpracování obrazu * MeSH
• Publikační typ
• časopisecké články MeSH
• komentáře MeSH

The simulations of cells and microscope images thereof have been used to facilitate the development, selection, and validation of image analysis algorithms employed in cytometry as well as for modeling and understanding cell structure and dynamics beyond what is visible in the eyepiece. The simulation approaches vary from simple parametric models of specific cell components-especially shapes of cells and cell nuclei-to learning-based synthesis and multi-stage simulation models for complex scenes that simultaneously visualize multiple object types and incorporate various properties of the imaged objects and laws of image formation. This review covers advances in artificial digital cell generation at scales ranging from particles up to tissue synthesis and microscope image simulation methods, provides examples of the use of simulated images for various purposes ranging from subcellular object detection to cell tracking, and discusses how such simulators have been validated. Finally, the future possibilities and limitations of simulation-based validation are considered. © 2016 International Society for Advancement of Cytometry.

• Klíčová slova
• cell imaging, cell model, digital cell, digital phantom, ground truth, image cytometry, simulation, validation, virtual imaging,
• MeSH
• algoritmy MeSH
• interpretace obrazu počítačem metody   MeSH
• lidé MeSH
• obrazová cytometrie metody   MeSH
• rozpoznávání automatizované metody   MeSH
• umělá inteligence MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Novel synthetic approaches for the development of multimodal imaging agents with high chemical stability are demonstrated. The magnetic cores are based on La0.63Sr0.37MnO3 manganite prepared as individual grains using a flux method followed by additional thermal treatment in a protective silica shell allowing to enhance their magnetic properties. The cores are then isolated and covered de novo with a hybrid silica layer formed through the hydrolysis and polycondensation of tetraethoxysilane and a fluorescent silane synthesized from rhodamine, piperazine spacer, and 3-iodopropyltrimethoxysilane. The aminoalkyltrialkoxysilanes are strictly avoided and the resulting particles are hydrolytically stable and do not release dye. The high colloidal stability of the material and the long durability of the fluorescence are reinforced by an additional silica layer on the surface of the particles. Structural and magnetic studies of the products using XRD, TEM, and SQUID magnetometry confirm the importance of the thermal treatment and demonstrate that no mechanical treatment is required for the flux-synthesized manganite. Detailed cell viability tests show negligible or very low toxicity at concentrations at which excellent labeling is achieved. Predominant localization of nanoparticles in lysosomes is confirmed by immunofluorescence staining. Relaxometric and biological studies suggest that the functionalized nanoparticles are suitable for imaging applications.

• Klíčová slova
• Cell labeling, Dual probes, MRI, Magnetic nanoparticles, Manganites, Molten salt synthesis, Silica coating,
• MeSH
• fibroblasty cytologie   metabolismus   MeSH
• fluorescence MeSH
• fluorescenční protilátková technika MeSH
• HeLa buňky MeSH
• Jurkat buňky MeSH
• kultivované buňky MeSH
• kůže cytologie   metabolismus   MeSH
• lanthan chemie   MeSH
• lidé MeSH
• magnetická rezonanční tomografie MeSH
• magnetické nanočástice chemie   MeSH
• membránové glykoproteiny asociované s lyzozomy imunologie   metabolismus   MeSH
• monoklonální protilátky imunologie   MeSH
• oxid křemičitý chemie   MeSH
• povrchové vlastnosti MeSH
• průtoková cytometrie MeSH
• silany chemie   MeSH
• sloučeniny manganu chemie   MeSH
• stroncium chemie   MeSH
• transmisní elektronová mikroskopie MeSH
• velikost částic MeSH
• viabilita buněk MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• LAMP1 protein, human MeSH Prohlížeč
• lanthan MeSH
• magnetické nanočástice MeSH
• manganite MeSH Prohlížeč
• membránové glykoproteiny asociované s lyzozomy MeSH
• monoklonální protilátky MeSH
• oxid křemičitý MeSH
• silany MeSH
• sloučeniny manganu MeSH
• stroncium MeSH
• tetraethoxysilane MeSH Prohlížeč

PURPOSE: The purpose of this study was to investigate whether (44)Sc-labeled puromycin can be utilized for imaging of protein synthesis in vivo. METHODS: For micro-positron emission tomographic (μPET) studies, 20-25 MBq of [(44)Sc]-DOTA-puromycin was administered to tumor-bearing rats, and animals were scanned for 1 h dynamically. Results were further validated by dissecting organs and tissues of the animals after the measurement and in vitro blocking experiments using puromycin or cycloheximide to block protein synthesis. RESULTS: μPET images of tumor-bearing rats showed significant tumor uptake of [(44)Sc]-DOTA-puromycin and a clear-cut tumor visualization. In both blocking experiments, cellular uptake of [(44)Sc]-DOTA-puromycin ([(44)Sc]-DOTA-Pur) could be suppressed by blocking protein synthesis. CONCLUSIONS: We report for the first time successful μPET imaging with (44)Sc obtained from a (44)Ti/(44)Sc generator, as well as noninvasive μPET imaging of ribosomal activity, respectively protein synthesis, with a puromycin-based radiopharmaceutical and the direct correlation between cellular uptake of [(44)Sc]-DOTA-Pur and protein synthesis.

• MeSH
• heterocyklické sloučeniny monocyklické chemie   farmakokinetika   farmakologie   MeSH
• kinetika MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• molekulární zobrazování metody   MeSH
• nádorové buněčné linie MeSH
• pozitronová emisní tomografie MeSH
• proteiny analýza   chemie   metabolismus   MeSH
• proteosyntéza MeSH
• puromycin analogy a deriváty   farmakokinetika   farmakologie   MeSH
• skandium chemie   farmakokinetika   MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid MeSH Prohlížeč
• heterocyklické sloučeniny monocyklické MeSH
• proteiny MeSH
• puromycin MeSH
• skandium MeSH

The cell surface receptor claudin-4 (Cld-4) is upregulated in various tumours and represents an important emerging target for both diagnosis and treatment of solid tumours of epithelial origin. The C-terminal fragment of the Clostridium perfringens enterotoxin cCPE290-319 appears as a suitable ligand for targeting Cld-4. The synthesis of this 30mer peptide was attempted via several approaches, which has revealed sequential SPPS using three pseudoproline dipeptide building blocks to be the most efficient one. Labelling with fluorine-18 was achieved on solid phase using N-succinimidyl 4-[18F]fluorobenzoate ([18F]SFB) and 4-[18F]fluorobenzoyl chloride as 18F-acylating agents, which was the most advantageous when [18F]SFB was reacted with the resin-bound 30mer containing an N-terminal 6-aminohexanoic spacer. Binding to Cld-4 was demonstrated via surface plasmon resonance using a protein construct containing both extracellular loops of Cld-4. In addition, cell binding experiments were performed for 18F-labelled cCPE290-319 with the Cld-4 expressing tumour cell lines HT-29 and A431 that were complemented by fluorescence microscopy studies using the corresponding fluorescein isothiocyanate-conjugated peptide. The 30mer peptide proved to be sufficiently stable in blood plasma. Studying the in vivo behaviour of 18F-labelled cCPE290-319 in healthy mice and rats by dynamic PET imaging and radiometabolite analyses has revealed that the peptide is subject to substantial liver uptake and rapid metabolic degradation in vivo, which limits its suitability as imaging probe for tumour-associated Cld-4.

• Klíčová slova
• 18F-fluorobenzoylation, Claudin family of tight junction proteins, Difficult peptide sequences, Molecular imaging, Radiolabelled peptides, Small animal positron emission tomography,
• MeSH
• buňky HT-29 MeSH
• cílená molekulární terapie MeSH
• claudin-4 antagonisté a inhibitory   chemie   metabolismus   MeSH
• enterotoxiny chemická syntéza   chemie   farmakokinetika   farmakologie   MeSH
• izotopové značení MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• ligandy MeSH
• molekulární mimikry fyziologie   MeSH
• molekulární zobrazování MeSH
• myši nahé MeSH
• myši MeSH
• nádory farmakoterapie   MeSH
• potkani Wistar MeSH
• pozitronová emisní tomografie MeSH
• radioizotopy fluoru chemie   MeSH
• techniky syntézy na pevné fázi MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• claudin-4 MeSH
• enterotoxin, Clostridium MeSH Prohlížeč
• enterotoxiny MeSH
• Fluorine-18 MeSH Prohlížeč
• ligandy MeSH
• radioizotopy fluoru MeSH

The approach for the detection of replicational activity in cells using 5-bromo-2'-deoxyuridine, a low concentration of hydrochloric acid and exonuclease III is presented in the study. The described method was optimised with the aim to provide a fast and robust tool for the detection of DNA synthesis with minimal impact on the cellular structures using image and flow cytometry. The approach is based on the introduction of breaks into the DNA by the low concentration of hydrochloric acid followed by the subsequent enzymatic extension of these breaks using exonuclease III. Our data showed that the method has only a minimal effect on the tested protein localisations and is applicable both for formaldehyde- and ethanol-fixed cells. The approach partially also preserves the fluorescence of the fluorescent proteins in the HeLa cells expressing Fluorescent Ubiquitin Cell Cycle Indicator. In the case of the short labelling pulses that disabled the use of 5-ethynyl-2'-deoxyuridine because of the low specific signal, the described method provided a bright signal enabling reliable recognition of replicating cells. The optimized protocol was also successfully tested for the detection of trifluridine, the nucleoside used as an antiviral drug and in combination with tipiracil also for the treatment of some types of cancer.

• MeSH
• bromodeoxyuridin metabolismus   MeSH
• buněčný cyklus * MeSH
• buňky A549 MeSH
• exodeoxyribonukleasy metabolismus   MeSH
• fluorescenční mikroskopie MeSH
• HeLa buňky MeSH
• kyselina chlorovodíková farmakologie   MeSH
• lidé MeSH
• průtoková cytometrie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• bromodeoxyuridin MeSH
• exodeoxyribonuclease III MeSH Prohlížeč
• exodeoxyribonukleasy MeSH
• kyselina chlorovodíková MeSH

Data-driven cell tracking and segmentation methods in biomedical imaging require diverse and information-rich training data. In cases where the number of training samples is limited, synthetic computer-generated data sets can be used to improve these methods. This requires the synthesis of cell shapes as well as corresponding microscopy images using generative models. To synthesize realistic living cell shapes, the shape representation used by the generative model should be able to accurately represent fine details and changes in topology, which are common in cells. These requirements are not met by 3D voxel masks, which are restricted in resolution, and polygon meshes, which do not easily model processes like cell growth and mitosis. In this work, we propose to represent living cell shapes as level sets of signed distance functions (SDFs) which are estimated by neural networks. We optimize a fully-connected neural network to provide an implicit representation of the SDF value at any point in a 3D+time domain, conditioned on a learned latent code that is disentangled from the rotation of the cell shape. We demonstrate the effectiveness of this approach on cells that exhibit rapid deformations (Platynereis dumerilii), cells that grow and divide (C. elegans), and cells that have growing and branching filopodial protrusions (A549 human lung carcinoma cells). A quantitative evaluation using shape features and Dice similarity coefficients of real and synthetic cell shapes shows that our model can generate topologically plausible complex cell shapes in 3D+time with high similarity to real living cell shapes. Finally, we show how microscopy images of living cells that correspond to our generated cell shapes can be synthesized using an image-to-image model.

• Klíčová slova
• Cell shape modeling, Generative model, Implicit neural representation, Neural network,
• MeSH
• Caenorhabditis elegans * MeSH
• lidé MeSH
• mitóza MeSH
• nádory plic * MeSH
• neuronové sítě MeSH
• počítačové zpracování obrazu metody   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Amphiphilic gradient copolymers are promising alternatives to block copolymers for self-assembled nanomaterials due to their straightforward synthesis via statistical copolymerization of monomers with different reactivities and hydrophilicity. By carefully selecting monomers, nanoparticles can be synthesized in a single step through gradient copolymerization-induced self-assembly (gPISA). We synthesized highly sensitive 19F MRI nanotracers via aqueous dispersion gPISA of hydrophilic poly(ethylene glycol) methyl ether methacrylate (PEGMA) with core-forming N,N-(2,2,2-trifluoroethyl)acrylamide (TFEAM). The PPEGMA-grad-PTFEAM nanoparticles were optimized to achieve spherical morphology and exceptional 19F MRI performance. Noncytotoxicity was confirmed in Panc-1 cells. In vitro 19F MR relaxometry and imaging demonstrated their diagnostic imaging potential. Notably, these gradient copolymer nanotracers outperformed block copolymer analogs in 19F MRI performance due to their gradient architecture, enhancing 19F relaxivity. The synthetic versatility and superior 19F MRI performance of gradient copolymers highlight their potential in advanced diagnostic imaging applications.

• MeSH
• hydrofobní a hydrofilní interakce MeSH
• kontrastní látky chemie   chemická syntéza   MeSH
• lidé MeSH
• magnetická rezonanční tomografie metody   MeSH
• methakryláty * chemie   MeSH
• nádorové buněčné linie MeSH
• nanočástice chemie   MeSH
• polyethylenglykoly * chemie   MeSH
• polymerizace MeSH
• polymery chemie   chemická syntéza   MeSH
• zobrazování fluorovou magnetickou rezonancí metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• kontrastní látky MeSH
• methakryláty * MeSH
• polyethylene glycol methacrylate MeSH Prohlížeč
• polyethylenglykoly * MeSH
• polymery MeSH

Monodisperse superparamagnetic Fe3O4 nanoparticles coated with oleic acid were prepared by thermal decomposition of Fe(III) glucuronate. The shape, size, and particle size distribution were controlled by varying the reaction parameters, such as the reaction temperature, concentration of the stabilizer, and type of high-boiling-point solvents. Magnetite particles were characterized by transmission electron microscopy (TEM), as well as electron diffraction (SAED), X-ray diffraction (XRD), dynamic light scattering (DLS), and magnetometer measurements. The particle coating was analyzed by atomic absorption spectroscopy (AAS) and attenuated total reflection (ATR) Fourier transform infrared spectroscopy (FTIR) spectroscopy. To make the Fe3O4 nanoparticles dispersible in water, the particle surface was modified with α-carboxyl-ω-bis(ethane-2,1-diyl)phosphonic acid-terminated poly(3-O-methacryloyl-α-D-glucopyranose) (PMG-P). For future practical biomedical applications, nontoxicity plays a key role, and the PMG-P&Fe3O4 nanoparticles were tested on rat mesenchymal stem cells to determine the particle toxicity and their ability to label the cells. MR relaxometry confirmed that the PMG-P&Fe3O4 nanoparticles had high relaxivity but rather low cellular uptake. Nevertheless, the labeled cells still provided visible contrast enhancement in the magnetic resonance image. In addition, the cell viability was not compromised by the nanoparticles. Therefore, the PMG-P&Fe3O4 nanoparticles have the potential to be used in biomedical applications, especially as contrast agents for magnetic resonance imaging.

• Klíčová slova
• iron oxide, magnetic resonance imaging, nanoparticles, superparamagnetic, thermal decomposition,
• MeSH
• kontrastní látky chemie   MeSH
• krysa rodu Rattus MeSH
• kyselina glukuronová chemie   MeSH
• magnetická rezonanční tomografie metody   MeSH
• magnetické nanočástice chemie   MeSH
• potkani inbrední LEW MeSH
• potkani transgenní MeSH
• železité sloučeniny chemie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kontrastní látky MeSH
• kyselina glukuronová MeSH
• magnetické nanočástice MeSH
• železité sloučeniny MeSH

A new facile synthetic strategy was developed to prepare bifunctional monophosphinic acid Ln-DOTA derivatives, Gd-DO2AGAPNBn and Gd- DO2AGAPABn. The relaxivities of the Gd-complexes are enhanced compared to Gd-DOTA. Monophosphinic acid arm of these Gd-complexes affords enhancement of inner sphere water exchange rate due to its steric bulkiness. The different functionalities of DO2AGAPNBn were appended in trans positions and are designed to conjugate identical or different vectors according to the potential applications. The conjugation of Gd-DO2AGAPABn with E3 peptide known to target apoptosis was successfully performed and in vivo MRI allowed cell death detection in a mouse model.

• Klíčová slova
• Contrast agents, Gadolinium complex, Macrocyclic ligands, Peptide conjugation, Relaxivity,
• MeSH
• heterocyklické sloučeniny monocyklické chemická syntéza   chemie   MeSH
• kontrastní látky chemická syntéza   chemie   MeSH
• magnetická rezonanční tomografie MeSH
• molekulární struktura MeSH
• multimodální zobrazování * MeSH
• myši MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• 1,4,7,10-tetraazacyclododecane- 1,4,7,10-tetraacetic acid MeSH Prohlížeč
• heterocyklické sloučeniny monocyklické MeSH
• kontrastní látky MeSH