•The frog skin-derived frenatin 2.1S promotes recruitment of cytotoxic NK cells.•Frenatin 2.1S enhances activational state and tumoricidal capacities of NK cells.•Frenatin 2.1S might be considered as ...a candidate for antitumor immunotherapy.
Frog skin is a source of peptides with various biological properties. Frenatin 2.1S, derived from norepinephrine-stimulated skin secretions of the Orinoco lime tree frog Sphaenorhynchus lacteus, exhibits immunostimulatory effects as demonstrated by the promotion of proinflammatory phenotypes of mononuclear cells in mouse peritoneal cavity and spleen. The aim of this study was to identify the populations of host cells sensitive to the action of frenatin 2.1S in vivo and to study its effects on their functional antitumor capacity. A single injection of frenatin 2.1S (100μg) in BALB/c mice increased the presence of peritoneal CD11c+ dendritic cells and CD3+ T cells 24h after administration and there was a significant increase in the number of IL-17 and CXCR3 expressing inflammatory T cells. Frenatin 2.1S treatment also increased the number of TNF-α expressing F4/80+ proinflammatory M1 macrophages. The most striking finding of the study is the marked increase of the number of peritoneal natural killer (NK) cells following frenatin 2.1S injection. Further, frenatin 2.1S administration led to activation of NK cells as evaluated by increased expression of NKG2D, FasL, CD69 and CD107a. The increased ratio of interferon-γ vs. IL-10 producing NK cells is further indication of the proinflammatory action of frenatin 2.1S. Peptide treatment enhanced the tumoricidal action of peritoneal NK cells on 4T1 mouse mammary carcinoma cells as revealed by the real-time automated monitoring of cell status. Our data demonstrate that frenatin 2.1S promotes activation and cytotoxic capacity of NK cells and should be regarded as a candidate for antitumor immunotherapy.
•Frenatin 2.1S enhances activation state and homing capacity of mouse peritoneal Th1 type lymphocytes and NKT cells.•Frenatin 2.1S increases the percentage of (F4/80+CD11c+CD206+) pro-inflammatory M1 ...macrophages.•Frenatin 2.1S enhances the expression of MHC class II molecules on F4/80+CD11c+ macrophages.•Frenatin 2.1S increases the percentage of peritoneal B cells of the (CD19+CD11b+CD5+) B1a phenotype.
Host-defense peptides secreted by epithelial cells exhibit cytotoxic and immunoregulatory effects in order to protect the organism against invading microorganisms. Antimicrobial peptides derived from frog skin display both immunostimulatory and immunosuppressive actions as demonstrated by in vitro cytokine production by macrophages. Frenatin 2.1S, first isolated from skin secretions of the frog, Sphaenorhynchus lacteus (Hylidae), enhances the in vitro production of pro-inflammatory IL-1β, TNF-α and IL-23 by mouse peritoneal cells. In order to test whether the immunostimulatory action of frenatin 2.1S may be reproduced in vivo, effects of intraperitoneal injections of this peptide on mononuclear cells in the peritoneum and spleen were determined 24h after administration. The data indicate that frenatin 2.1S enhances the activation state and homing capacity of Th1 type lymphocytes and NKT cells in the mouse peritoneal cavity, as evaluated by increased expression of early activation marker CD69 among T and NKT cells and chemokine receptor CXCR3 among T cells. Frenatin 2.1S significantly increases the percentage of (F4/80+CD11c+CD206+) pro-inflammatory M1 macrophages and enhances the expression of MHC class II molecules on F4/80+CD11c+ macrophages in the mouse peritoneal cavity. Additionally, injection of frenatin 2.1S, in the presence or absence of lipopolysaccharide, increases the percentage of peritoneal B cells of the (CD19+CD11b+CD5+) B1a phenotype thus contributing to an inflammatory milieu. We suggest that the immunostimulatory effect of frenatin 2.1S may have therapeutic relevance in disease states, such as certain types of cancer, in which an enhanced inflammatory response may be beneficial.
Ceramic pigments based on cerium oxide were synthesized by self-propagating room temperature method and their color properties were assessed from the viewpoint of potential environmentally non-toxic ...pink pigments. Thermal stabilities of the pigments were examined at 600, 900 and 1200 °C. According to X-ray powder diffraction and Raman spectroscopy results, all obtained pigments were single-phase solid solutions of cerium oxide, independent of the concentration of dopants. The X-ray analysis showed that the crystallites were of nanometric dimensions, as recorded and by transmission electron microscopy analysis. Color characteristics of solid solutions, which depended on concentration erbium ions and calcination temperature, and their position in the chromaticity diagram were studied by ultraviolet–visible spectrophotometry, which confirmed potential application of environmentally friendly pigments of desired color. The color efficiency of pigments was also evaluated by colorimetric analysis.
•New inorganic pigments Ce1−xErxO2−δ (x = 0.05–0.20) were prepared by SPRT method.•Single-phase form was evidenced for each pigment by XRPD and Raman spectroscopy.•The XRPD and TEM analysis showed that the crystallites of nanometric dimensions.•The synthesized pigments show great thermal stability and various pink shades.•Pigments may be a potential alternative to the classical toxic pink pigments.
Simple route was used for synthesis of nanostructured titania samples doped with 3 and 6mol% of Cr3+. Titanium(IV)-isopropoxide and water were used as starting materials and as an agents for ...controlling hydrolysis and condensation reactions. The phase evolution of titania (TiO2) was followed by calcination at 400, 600 and 800°C. The synthesized powders were examined by field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD). Single-phase anatase was obtained at low temperature (400°C) in all cases. The photocatalytic activity of TiO2 doped nanopowders was evaluated by the photocatalytic degradation of crystal violet in aqueous solution. The present study indicates that this simple synthesis method can be an effective route to produce efficient photoactive doped anatase nanopowders.
New manufacturing process for nanometric SiC Babić, Biljana; Bučevac, Dušan; Radosavljević-Mihajlović, Ana ...
Journal of the European Ceramic Society,
July 2012, 2012-07-00, Letnik:
32, Številka:
9
Journal Article
Recenzirano
Nanometric β-SiC powder was prepared by carbothermal reduction of freeze-dried gel. Initially, the gel was obtained by polycondensation of sol consisting of resorcinol and formaldehyde as a source of ...C and tetraethoxysilane as a source of silicon. The effect of temperature and time of heat treatment (carbothermal reduction) as well as the effect of C/Si ratio on SiC powder properties was studied. It was possible to obtain nanosized (∼20nm) β-SiC powder after one-hour heat treatment at relatively low temperature of 1200°C. The powder was successfully synthesised without the need for excess carbon which is typical for conventional carbothermal reduction using some other sources of graphite. The increase in temperature of heat treatment to 1400°C caused considerable growth of SiC particles up to 400nm. It was found that prolonged heat treatment at 1200°C is an effective way to obtain well crystallized SiC and keep the size of SiC particles below 50nm at the same time.
•Single phase solid solution Ce1−xBixO2−δ with the composition of x=0.1–0.5 were successfully synthesized at room temperature using simple and fast Self Propagating Room Temperature procedure ...(SPRT).•Thermal stability of Ce1−xBixO2−δ solid solutions was investigated at various temperatures up to 1400°C.•It was revealed that all samples with concentration of bismuth higher than 10at.% are unstable during thermal treatment.•Bi leaving the structure of ceria and formation of β-Bi2O3 and β′-Bi2O3 as secondary phases.
Single phase solid solution Ce1−xBixO2−δ with the composition of x=0.1–0.5 were successfully synthesized at room temperature using simple and fast Self Propagating Room Temperature procedure (SPRT). Thermal stability of these solid solutions with different concentration of Bi cation was investigated at various temperatures up to 1400°C by applying thermogravimetric analysis (DTA/DTG/TG). Powders were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and Infra Red spectroscopy (IR). It was revealed that all samples with concentration of bismuth higher than 10at.% are unstable during thermal treatment, resulting in Bi leaving the structure of ceria and formation of β-Bi2O3 as second phase. Moreover, at a certain temperatures bismuth begins to evaporate.
Introduction. Gastric cancer (GC) represents one of the most common cancers worldwide, frequently diagnosed at advanced stages with poor prognosis, indicating on need for new diagnostic and ...prognostic markers. The aim of the study was to determine the expression of IL-32, proinflammatory and angiogenic mediators, in patients with diffuse and intestinal gastric cancer and the relationship with clinicopathological aspects. Material and Methods. The tissue samples of diffuse and intestinal types of tumor of 70 patients with gastric cancer were analyzed. Expression of IL-32, VEGF, IL-17, and CD31 was measured by immunohistochemistry. Results. IL-32 expression was significantly lower in tissue samples from patients with diffuse type of gastric cancer that is also a severe and more progressive form (TNM stages III and IV, poor histological differentiation, and higher nuclear grade III). Expression of IL-17 was also decreased in patients with diffuse type of gastric cancer. Microvascular density was diminished in diffuse type of gastric cancer. Conclusions. Downregulated expression of IL-32 in tumor tissue of patients with diffuse type of gastric cancer may implicate on its role in limiting ongoing proinflammatory and proangiogenic processes. This emphasizes on unrecognized role of IL-32 in biology of diffuse type of gastric cancer.
Sphene (CaTiSiO
5
), a calcium titanosilicate ceramic has been prepared from a powder mixture of CaCO
3
, TiO
2
and SiO
2
using vibro-milling for homogenization and activation of precursors. During ...the high-pressure and high-temperature synthesis (HPS) process at 4 GPa and 1,200 °C, sphene undergoes into phase transition, from room-temperature phase
P
2
1
/a
to high-temperature phase
A
2
/a
. Evidence of that structural phase transition is given in this paper using infrared, Raman spectroscopy and X-ray powder diffraction. Rietveld refinement was employed to get the structural information of the synthesized powder. The most important structural change due to phase transition, the disappearance of the characteristic out-of-center distortion of the Ti atom and moving to the center of octahedra, was confirmed. HPS is an effective method for producing full-dense ceramics without any additives. Reduction of particle size occurred during high-pressure compaction. Microstructure and particle size of both phases were analyzed by scanning electron microscopy.
•Mechanical activation of precursors has been used for the preparation of Cr-doped sphene ceramic pigments (CaTi1−yCrySiO5).•The average particle size is around 1μm, which is desirable for ...application.•The optimum pigment (best hue with lowest Cr content) is obtained with 0.1% Cr.•Both chromium ions (Cr4+ and Cr3+), find itself within distorted octahedral coordination.
Mechanical activation of precursors has been used for the preparation of Cr-doped sphene ceramic pigments (CaTi1−yCrySiO5). Ceramic material has been prepared from a powder mixture of CaCO3, TiO2, SiO2 and Cr(NO3)⋅9H2O using vibro-milling for homogenization and activation of precursors. The mechanochemical process initially yielded amorphous powders, which on further calcination, crystallized to yield Cr-doped sphene ceramic pigment. Phase evolution in CaTi1−yCrySiO5 composition with thermal treatment was investigated by X-ray powder diffraction (XRPD). Texture properties and particle size distribution were analyzed by scanning electron microscopy (SEM) and laser diffraction, respectively. UV/Vis reflectance spectra are used to determinate the behavior of the chromium ion. The color efficiency of pigments was evaluated by colorimetric analysis (CIE L*a*b system). Photoluminescence measurements were also performed.
Platinum-based drugs are widely recognized efficient anti-tumor agents, but faced with multiple undesirable effects. Here, four dinuclear platinum(II) complexes, {Pt(1,2-pn)Cl}
2
(
μ
-pydz)Cl
2
(
C1
...), {Pt(ibn)Cl}
2
(
μ
-pydz)Cl
2
(
C2
), {Pt(1,3-pn)Cl}
2
(
μ
-pydz)Cl
2
(
C3
) and {Pt(1,3-pnd)Cl}
2
(
μ
-pydz)Cl
2
(
C4
), were designed (pydz is pyridazine, 1,2-pn is ( ±)-1,2-propylenediamine, ibn is 1,2-diamino-2-methylpropane, 1,3-pn is 1,3-propylenediamine, and 1,3-pnd is 1,3-pentanediamine). Interactions and binding ability of
C1
–
C4
complexes with calf thymus DNA (CT-DNA) has been monitored by viscosity measurements, UV–Vis, fluorescence emission spectroscopy and molecular docking. Binding affinities of
C1
–
C4
complexes to the bovine serum albumin (BSA) has been monitored by fluorescence emission spectroscopy. The tested complexes exhibit variable cytotoxicity toward different mouse and human tumor cell lines.
C2
shows the most potent cytotoxicity, especially against mouse (4T1) and human (MDA-MD468) breast cancer cells in the dose- and time-dependent manner.
C2
induces 4T1 and MDA-MD468 cells apoptosis, further documented by the accumulation of cells at sub-G1 phase of cell cycle and increase of executive caspase 3 and caspase 9 levels in 4T1 cells.
C2
exhibits anti-proliferative effect through the reduction of cyclin D3 and cyclin E expression and elevation of inhibitor p27 level. Also,
C2
downregulates c-Myc and phosphorylated AKT, oncogenes involved in the control of tumor cell proliferation and death. In order to measure the amount of platinum(II) complexes taken up by the cells, the cellular platinum content were quantified. However,
C2
failed to inhibit mouse breast cancer growth in vivo. Chemical modifications of tested platinum(II) complexes might be a valuable approach for the improvement of their anti-tumor activity, especially effects in vivo.
Graphical abstract
Dinuclear platinum(II) complex {Pt(ibn)Cl}
2
(
μ
-pydz)Cl
2
shows anti-tumor activity, triggers the apoptosis and reduces the proliferation of mouse breast cancer cells in vitro. However, its inhibitory effect on tumor growth in vivo is absent.
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