scholarly journals Effect of crosslinking with riboflavin and ultraviolet a (UVA) on the scleral tissue structure

2017 ◽  
Vol 10 (2) ◽  
pp. 6-12
Author(s):  
Mukharram M Bikbov ◽  
Valentina K Surkova ◽  
Emin L Usubov ◽  
Nikolaj A Nikitin ◽  
Mikhail Nikolaevich Astrelin
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Average Diameter ◽  
Tissue Structure ◽  
In Vitro Experiments ◽  
Pathological Changes ◽  
Ultraviolet A ◽  
Intermediate Space ◽  
Special Software

Purpose. To evaluate the effect of the scleral crosslinking with riboflavin and ultraviolet A (UVA) on the scleral tissue structure in vitro experiments. Material and methods. The study was conducted on 7 porcine cadaver eyes. Two parallel scleral strips were excised from each eyeball, one of which was subjected to crosslinking procedure (instillation of 0.1% aqueous solution of riboflavin mononucleotide for 20 minutes, ultraviolet irradiation of 3 mW /cm2 for 30 minutes), second was used as control. Scleral structure was evaluated by light (Van Gieson’s stain) and electron microscopy. Morphometric analysis of the microphotographs was performed using special software. Results. As a result of crosslinking, the average packing density of collagen fibers increased by 8.2%, the area of the intermediate space decreased by 5.2%, the average diameter of collagen fibrils increased by 12%. There were no pathological changes in scleral structures. Conclusion. Obtained results confirm the efficacy of scleral crosslinking with riboflavin/UVA in the formation of additional crosslinks, and the procedure safety for the scleral tissue.

scholarly journals Тhe Safety Assessment of the Ultraviolet Scleral Crosslinking with Riboflavin/UVA in Experiment

2019 ◽  
Vol 16 (1S) ◽  
pp. 108-111
Author(s):  
M. N. Astrelin ◽  
V. K. Surkova
Keyword(s):  
Aqueous Solution ◽  
Side Effects ◽  
Functional State ◽  
Safety Assessment ◽  
Pathological Changes ◽  
Ultraviolet A ◽  
Total Exposure Time ◽  
The Right ◽  
And Control

The purpose is to evaluate the safety of the scleral crosslinking with riboflavin/ultraviolet A (UVA) in an experiment in vivo. Materials and methods. The study was carried out on 34 Chinchilla rabbits (68 eyes). The right eyes were crosslinked (34 eyes), the left eyes were served as controls (34 eyes). Scleral crosslinking (SCXL) was performed with sclera saturation with a photosensitizer (0.1 % aqueous solution of riboflavin) for 20 minutes and its subsequent irradiation with ultraviolet A (wavelength of 370 ± 5 nm, irradiance — 3 mW/cm2), total exposure time — 30 minutes (6 cycles of 5 minutes). The effect of the procedure on the anatomical and functional state of the eye layers was assessed with high-resolution optical coherent tomography (OCT) and electroretinography (ERG) before crosslinking, a day, 7 and 30 days after it. Results. OCT did not reveal any pathological changes after scleral crosslinking with riboflavin/UVA. The layers of the retina, choroid and sclera were clearly visualized. The performed morphometric analysis has showed the absence of statistically significant changes in the eye layers thickness after ultraviolet crosslinking. The amplitude-time characteristics and the shape of the electroretinogram of the experimental and control rabbits eyes were identical during all periods of observation, had a classic appearance. All waves of ERG were well expressed. It indicates a satisfactory functional state of the retinal neuroreceptor mechanisms. Conclusion. For ultraviolet crosslinking we used UVA with an irradiance of 3 mW/cm2 for 30 minutes and a 0.1 % aqueous solution of riboflavin without dextran and did not reveal any side effects of the procedure. Thus, scleral crosslinking with these parameters is safe for the eye layers in an experiment in vivo.

Environmentally Friendly Aqueous Solution Synthesis of Hierarchical CaWO4 Microspheres at Room Temperature

2008 ◽  
Vol 8 (3) ◽  
pp. 1288-1294 ◽  
Author(s):  
Wenshou Wang ◽  
Liang Zhen ◽  
Chengyan Xu ◽  
Baoyou Zhang ◽  
Wenzhu Shao
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Large Scale ◽  
Room Temperature ◽  
Blue Emission ◽  
Environmentally Friendly ◽  
Average Diameter ◽  
Solution Synthesis ◽  
Chemical Route ◽  
Hierarchical Microspheres

An environmentally friendly route for the synthesis of hierarchical CaWO4 microspheres with novel morphology at room temperature has been successfully developed. CaCl2 and Na2WO4 were used as reaction regents, and distilled water was used as an environmentally friendly solvent. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and photoluminescence spectroscopy. This green wet-chemical route provides a simple, one-step, low-cost approach for the large-scale synthesis of hierarchical CaWO4 microspheres with relatively uniform diameters of 3–6 μm. The hierarchical microspheres are built up with numerous nanorods with an average diameter of 50 nm, which are radially oriented to the microsphere center. SEM observations of different intermediates indicate the possible growth process, in which the hierarchical structure growth is from nuclei through kayak-like, rod-like, peanut-like, dumbbell-like, and peach-like structures to final microspheres, via "self-assembled preferential end growth" of kayak-like particles in aqueous solution. The hierarchical CaWO4 micro-spheres exhibit a strong, broad blue emission peak of 412 nm.

scholarly journals Surface coat on the epithelium of developing palatine shelves in the mouse as revealed by electron microscopy

Development ◽  
1974 ◽  
Vol 31 (3) ◽  
pp. 683-692
Author(s):  
R. M. Greene ◽  
D. M. Kochhar
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Ruthenium Red ◽  
Entire Length ◽  
Surface Epithelium ◽  
Positive Staining ◽  
Surface Coat ◽  
In Vitro Experiments ◽  
Acid Mucopolysaccharides

The fine structure of the surface epithelium of developing palatine shelves in the mouse was studied from days 11 through 14 of gestation. Ruthenium red, a cationic stain used as an ultrastructural indicator of acid mucopolysaccharides, was employed to detect the presence of any surface coat. Positive staining was first observed on day 12 of gestation and was seen to be present throughout the period of shelf elevation and fusion. It was seen over medial and lateral surfaces as well as the inferior tip of vertical shelves. The surface coat was found to be present along the entire length of the shelf, extending superiorly up the medial and lateral epithelial borders until it abruptly disappeared. Since this surface coat first appeared approximately 48 h prior to shelf elevation, it is suggested that its appearance may be associated with the ability of palatine shelves to undergo fusion as shown by previous in vitro experiments. The time of acquisition by the shelves of this ‘fusing potential’ is also in the range of 48 h before shelf elevation.

scholarly journals Synthesis and biological activity of raltitrexed-carrier conjugates.

2010 ◽  
Vol 57 (1) ◽  
Author(s):  
Monika Jagiello ◽  
Urszula Kanska ◽  
Dmitry Nevozhay ◽  
Janusz Boratynski
Keyword(s):  
Cell Cycle ◽  
Aqueous Solution ◽  
Biological Activity ◽  
Covalent Binding ◽  
Maximum Yield ◽  
Free Drug ◽  
S Phase ◽  
In Vitro Experiments ◽  
M Phase

Drugs used in chemotherapy give undesirable side effects, e.g., cardiotoxicity, leucopenia, hair loss and others. Covalent binding of a drug with a carrier may change its biodistribution, elimination and/or rate of transformation in the organism. The aim of this work was to synthesize conjugates of anticancer drug - raltitrexed (RTX) with lysozyme, bovine serum albumin (BSA), and dextran T40 and to investigate their cytotoxicity and influence on the cell cycle in comparison with the free drug. Before conjugation RTX was transformed into anhydride by treatment with dicyclohexylcarbodiimide in dimethylformamide. Activated RTX was added into aqueous solution of carriers at different pH (from 8.5 to 10.5) for 3 to 15 min. The reaction was stopped by reducing the pH to 7.0. Maximum yield of the reaction was obtained at pH 10 for BSA as well as for dextran. The highest level of substitution was obtained after 5 min of the reaction. In in vitro experiments on three cell lines: SW707, LoVo and A549, all conjugates tested had up to a few hundred times higher IC(50) than the free drug. Interestingly, it was noticed that the conjugates based on dextran and albumin were more cytotoxic than the free drug in the highest concentrations tested (1000 and 10000 ng/ml). The influence of RTX and the conjugates on SW707 cell cycle was studied. RTX blocked the cell cycle mostly in the G(0)-G(1) and S phase and increased the percentage of apoptotic cells. Cells in the G(2)-M phase were not observed. The conjugates blocked the cell cycle in the S phase and decreased the percentage of cells in the G(0)-G(1) phase.

scholarly journals Subfractionation of hepatic endosomes in Nycodenz gradients and by free-flow electrophoresis. Separation of ligand-transporting and receptor-enriched membranes

1985 ◽  
Vol 232 (1) ◽  
pp. 25-32 ◽  
Author(s):  
W H Evans ◽  
N Flint
Keyword(s):  
Electron Microscopy ◽  
Alkaline Phosphatase ◽  
Binding Sites ◽  
Average Diameter ◽  
Free Flow ◽  
Density Range ◽  
Short Intervals ◽  
Electrophoresis Separation ◽  
Isopycnic Centrifugation

The complexity of rat liver endosome fractions containing internalized radioiodinated asialotransferrin, asialo-(alkaline phosphatase), insulin and prolactin was investigated by using free-flow electrophoresis and isopycnic centrifugation in Nycodenz gradients. Two subfractions were separated by free-flow electrophoresis. Both subfractions contained receptors for asialoglycoprotein and insulin. Glycosyltransferase activities were associated with the more electronegative vesicles, whereas 5′-nucleotidase and alkaline phosphodiesterase activities were associated with the less electronegative vesicles. Three subfractions were separated on Nycodenz gradients. Two subfractions, previously shown to become acidified in vitro, contained the ligands. At short intervals after uptake (1-2 min), ligands were mainly in subfraction DN-2 (density 1.115 g/cm3), but movement into subfraction DN-1 (density 1.090 g/cm3) had occurred 10-15 min after internalization. Low amounts of glycosyltransferase activities were associated with subfraction DN-2, and 5′-nucleotidase and alkaline phosphodiesterase activities were mainly located in subfraction DN-1. The binding sites for asialoglycoproteins and insulin were distributed towards the higher density range in the Nycodenz gradients, thus indicating a segregation of receptor-enriched vesicles and those vesicles containing the various ligands 10-15 min after internalization. Electron microscopy of the subfractions separated on Nycodenz gradients indicated that whereas the ligand-transporting fractions consisted mainly of empty vesicles (average diameter 100-150 nm), the receptor-enriched component was more granular and smaller (average diameter 70-95 nm). The properties of the endosome subfraction are used to assign their origin to the regions of the endocytic compartment where ligand-receptor dissociation and separation occur.

Electrochemical Synthesis of Nanostructured Oxide Layers on Threaded Surfaces of Medical Implants

2018 ◽  
Vol 69 (7) ◽  
pp. 1636-1639 ◽  
Author(s):  
Octav Marius Russu ◽  
Gabriela Strnad ◽  
Laszlo Jakab-Farkas ◽  
Razvan Cazacu ◽  
Andrei Feier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Average Diameter ◽  
Electrochemical Anodization ◽  
Medical Implants ◽  
Oxide Layers ◽  
Self Organized ◽  
Nanostructured Oxide ◽  
Nanostructured Layers ◽  
Scanning Electron

Self organized nanostructured oxide layers were developed on threaded surfaces of medical implants made of Ti6Al4V alloy. The synthesis was done by electrochemical anodization in phosphate/fluoride based electrolyte. By anodization in an aqueous solution of 9.34 wt.% H3PO4 and 0.4 wt.% HF the threaded surfaces were covered by continuous, self ordered nanoporous oxide layers. Scanning electron microscopy (SEM) was used to evaluate the morphology of the nanostructured layers. The diameters of the nanopores depends on anodization potential, by using U = 24 V the openings had an average diameter of 40 nm, while using U = 30V the average nanopores diameter was of 63 nm. The current density was ~10 A/m2 in the steady state of potentiodynamic stage of anodization, and below 45 A/m2 in potentiostatic stage.

scholarly journals Synthesis and characterization of nanosized NiO2 and NiO using Triton® X-100

2009 ◽  
Vol 7 (1) ◽  
pp. 155-158 ◽  
Author(s):  
Mohammad Kooti ◽  
Mehdi Jorfi
Keyword(s):  
Electron Microscopy ◽  
Aqueous Solution ◽  
Scanning Electron Microscopy ◽  
Fine Powder ◽  
Average Diameter ◽  
Synthesis And Characterization ◽  
Xrd Diffraction ◽  
High Yields ◽  
Scanning Electron

AbstractNanosized NiO2 particles with an average diameter of 15 nm are prepared by treating of Ni(NO3)2 · 6H2O with an aqueous solution of KClO in the presence of Triton® X-100. This black fine powder of nickel peroxide was characterized by XRD diffraction, energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The as-prepared NiO2 can be easily transformed to nanosized NiO merely by washing it with acetone. The obtained NiO has an average diameter of 40 nm and was characterized by the same means used for NiO2. The nanoparticles of NiO2 and NiO were obtained in high yields and purities.

Preparation and Characterization of Mno.5Zno.5Fe2O4 @Au Composite Nanoparticles and its Anti-Tumor Effect on Glioma Cells

2011 ◽  
Vol 138-139 ◽  
pp. 907-913
Author(s):  
Yun Tao Li ◽  
Jing Liu ◽  
Li Wang ◽  
Jia Zhang ◽  
Zi Yu Wang ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Microscopy ◽  
Au Nanoparticles ◽  
Glioma Cells ◽  
Trisodium Citrate ◽  
Average Diameter ◽  
Composite Nanoparticles ◽  
Au Nanoparticle ◽  
Core Shell

To explore the preparation method and characters of a new gold nanoshells on maganese-zinc ferrite (Mno.5Zno.5Fe2O4@Au) composite nanoparticles. Mno.5Zno.5Fe2O4@Au nanoparticles with core/shell structure were synthesized by reduction of Au3+ with trisodium citrate in the presence of Mno.5Zno.5Fe2O4 magnetic nanoparticles (MZF-NPs) prepared by improved co-preciption with the character of superparamagnetism and detected by transmission electron microscopy (TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), energy dispersive spectrometry (EDS) and Marven laser particle size analyzer.Thermodynamic test was used to observe temperature change of various doses of Mno.5Zno.5Fe2O4@Au nanoparticles. The cytotoxicity of the Mno.5Zno.5Fe2O4@Au composite nanoparticles in vitro was tested by the MTT assay. The therapeutic effect of Mno.5Zno.5Fe2O4@Au composite nanoparticles combined with magnetic fluid hyperthermia (MFH) on human glioma cells were evaluated in vitro by an MTT assay.The results indicated that the Mno.5Zno.5Fe2O4@Au composite nanoparticles were prepared successfully. The core/shell particles were spherical with exact average diameter of them was 66.9nm.EDS showed each Mno.5Zno.5Fe2O4@Au nanoparticle contained Mn, Zn, Fe, O and Au elements, and this proved Au had successfully attached to Mn0.5Zn0.5Fe2O4.The result of thermodynamic test showed that Mno.5Zno.5Fe2O4@Au composite nanoparticles could serve as a heating source under alternating magnetic field (AMF) exposure leading to reach their steady temperature (40-45°C). Moreover, Mno.5Zno.5Fe2O4@Au composite nanoparticles didn’t show cytotoxicity in vitro. The therapeutic result reveals that Mno.5Zno.5Fe2O4@Au composite nanoparticles can significantly inhibit the growth of glioma cells.The conclusion was that the self-prepared Mno.5Zno.5Fe2O4@Au composite nanoparticles had strong magnetic responsiveness and good power absorption capabilities in the high frequency AMF,then they could suggested to be useful for glioma hyperthemia. Mno.5Zno.5Fe2O4 @Au composite nanoparticles can not only be directed to tumor region in a given magnetic field more exactly but also produce marked thermotherapy.

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