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At least 721 records · Page 40Linked to original sources

[Preparation and characterization of Mn-Zn ferrite oxygene nanoparticle for tumor thermotherapy].

With the sulfate as the materials and NaOH as precipitator, Mn(0.4)Zn(0.6)Fe2O4 nanoparticles were produced, which are proved to be spinel Mn-Zn ferrite analyzed by X-ray diffraction(XRD). Their shapes are approximately global examined by transmission electron microscopy(TEM) and their average diameter is 50 nm measured with image analysis-system. The Curie temperature was measured and in vitro heating test in a alternating magnetic field was carried out. The results show that the Curie temperature is 105. 407 degrees C, While its magnetic fluid could rise to 43 degrees C - 47 degrees C due to different concentration in a alternating magnetic field. The result provide theoretical and practical evidence to select an appropriate material and concentration for tumor

Electromagnetic Fields↗

[Comparative study of the toxicity of metal chlorides and a synthetic organic molluscacide, N-tritylmorpholine, in 2 fresh-water amphipods, Gammarus pulex and Echinogammarus berilloni].

The effects of three metal salts (BaCl2, CuCl2, ZnCl2) and of N-trityl-morpholine (Triphenmorph) were studied on two aquatic amphipod species, Gammarus pulex and Echinogammarus berilloni. Experiments were made up in eucalcic and oligocalcic waters for determining the LC50 at different exposure times. The order of toxicity was the same in eucalcic water with the two species: Triphenmorph greater than Cu2+ greater than Zn2+ greater than Ba2+. This order was the same in oligocalcic water with Echinogammarus berilloni; with Gammarus pulex, CuCl2 was more toxic than Triphenmorph.

Animals↗

Inhibitory effect of polaprezinc on the inflammatory response to Helicobacter pylori.

Helicobacter pylori-infected gastrointestinal mucosa is frequently infiltrated by polymorphonuclear leukocytes (PMN) and monocytes, and these invading cells have been implicated in gastrointestinal mucosal inflammation. To clarify the efficacy of polaprezinc, a chelate compound consisting of zinc and L-carnosine, against H pylori-induced inflammation including PMN infiltration, the in vitro effects of this drug on interleukin (IL)-8 production by an established gastric cancer cell line (MKN 45 cells) and on PMN-endothelial cell adhesive interactions was investigated. Polaprezinc and zinc sulphate inhibited IL-8 production by MKN 45 cells in response to stimulation with H pylori water extract (HPE) in a dose-dependent manner from 10(-7) M to 10(-5) M. In addition, the expression of CD11b and CD18 on PMN and PMN-dependent adhesion to endothelial cells elicited by HPE was inhibited by polaprezinc and zinc sulphate in a concentration-dependent manner. L-carnosine did not have any effects on IL-8 production or PMN-endothelial cell interactions. These results suggest that polaprezinc, mainly the zinc component, may inhibit H pylori-induced PMN-mediated gastric inflammation by attenuating CD11b/CD18 expression on PMN and IL-8 production from gastric epithelial cells.

Anti-Inflammatory Agents↗

Photomodification of the electrical properties of the plasma membrane: a comparison between 6 different membrane-active photosensitizers.

The present study deals with photomodification of the electrical properties of the plasma membrane of an epithelial cell line (opossum kidney (OK) cells). The effect of photofrin II (previously investigated) is compared with that of 5 other membrane-active sensitizers: sulfonated Zn-phthalocyanine, merocyanine 540, rose bengal, methylene blue and protoporphyrin IX (an endogenous sensitizer induced by addition of its biosynthetic precursor 5-aminolaevulinic acid). The study was performed in order to investigate whether photomodification of the ion transport properties of the plasma membrane by membrane-active sensitizers is a general and early event in cellular photosensitization. The changes in the electrical properties were monitored by application of the whole-cell and the inside-out configuration of the patch-clamp technique. Illumination in the presence of the compounds (apart from merocyanine 540) gave rise to similar changes of the electrical properties of the membrane: depolarization of the membrane potential, inactivation of a large-conductance, Ca2+-dependent K+-channel (maxi-KCa), and a strong increase of the leak conductance of the membrane. This similarity indicates the general character of the functional photomodifications by membrane-active sensitizers previously reported for photofrin II.

Aminolevulinic Acid↗

Porphyrin-perylene bisimide dyads and triads: synthesis and optical and coordination properties.

[structure: see text] Novel porphyrin perylene dyad and triad dyes have been prepared by the coupling of aminophenyltrisphenylporphyrin and tetraphenoxy-substituted perylenetetracarboxylic acid bisanhydrides in a one-step synthesis. Fluorescence spectra of these compounds reveal features that are attributable to emission of perylene bisimides as well as porphyrin excited states. The self-assembly behavior of zinc-metalated compounds with 4,4'-bipyridine and diazabenzoperylene has been investigated by (1)H NMR spectroscopy in CDCl(3), showing that oligomeric zigzag assemblies are formed.

Journal Article↗

Metal-induced alteration of the cell membrane/cytoplasm complex studied by flow cytometry and detergent lysis.

Flow cytometric analysis of the cell cycle is most effectively accomplished with membrane-/cytoplasm-free ("clean") nuclei. Non-ionic detergents (e.g. NP40 or Triton X-100) commonly are employed to solubilize cell membranes/cytoplasm to produce "clean" nuclei. Treatment of murine erythroleukemic cells (MELC) with tri-n-butyltin methoxide, cadmium acetate, zinc sulfate, or lead acetate alters the properties of the cell membrane/cytoplasm complex making it resistant to NP40 dissolution. On a molar basis, the organotin compound was more effective in inducing resistance to detergent-mediated dissolution than the inorganic metal compounds. Resistance to NP40-mediated dissolution was manifested as an increase in the flow cytometric parameters 90 degrees scatter and fluorescein isothiocyanate (FITC) fluorescence and was confirmed by light microscopy.

Acetates↗

Zinc mediated methyl transfer from trimethyl phosphate to chelating and non-chelating alkyl thiols. Model for Zn-dependent methyltransferases.

The methyl transfer from trimethyl phosphate to alkyl thiols was investigated in the presence of zinc ions and in the absence of strong base. The chelating thiol N-(2-mercaptoethyl)picolylamine (MEPAH) was methylated by trimethyl phosphate, in MeOH, in the presence of Zn salts whereas the reaction did not take place in the absence of Zn(2+). The pre-formed complex (MEPA)(2)Zn was methylated faster than the MEPAH in the presence of zinc ions The methyl transfer also took place in chloroform with similar yields at room temperature. When non-chelating hexanethiol was the methyl acceptor, a slower reaction took place in the presence of pyridine which was independent of Zn(2+). Kinetic studies of the methyl transfer from trimethyl phosphate to (MEPA)(2)Zn gave a second-order rate constant of 5.0 x 10(-5) M(-1) s(-1) as measured by 1H NMR spectroscopy in MeOH. The results obtained suggest that the methyl transfer to MEPA-Zn involves a zinc-bound thiolate.

Chelating Agents↗

Zn(II)-phthalocyanines as phototherapeutic agents for cutaneous diseases. Photosensitization of fibroblasts and keratinocytes.

Two tetrasubstituted (RLP024 and RLP040) and one monosubstituted (MRLP101) Zn-phthalocyanines were readily accumulated by three skin-derived cell lines (HT-1080 transformed human fibroblasts, 3T3 mouse embryo fibroblasts and HaCaT human keratinocytes) upon 1 h-incubation with 0.5-5 microM phthalocyanine concentrations. The affinity was markedly larger for the tetra- as compared with the mono-substituted phthalocyanine, even though smaller phthalocyanine amounts were generally recovered from keratinocytes. As a consequence, the two tetra-substituted phthalocyanines exhibited a higher phototoxicity against all the three cell lines. Typically, the cell survival decreased by at least 80% after 1 min irradiation with 600-700 nm light at a fluence-rate of 50 mW/cm2 in the presence of 5 microM phthalocyanine. Fluorescence microscopy and caspase-3 activation studies indicate that cell death of fibroblasts largely occurred by a random-necrotic process while the keratinocytes underwent cell death predominantly via apoptosis in spite of a very similar pattern of subcellular distribution of the phthalocyanines.

3T3 Cells↗

Effect of aluminum on delta-aminolevulinic acid dehydratase from mouse blood.

The objective of this study was to investigate aluminum deposition in whole blood and plasma of mice and the activity of blood delta-aminolevulinic acid dehydratase (ALA-D) after in vitro and in vivo exposure to this element. In vitro experiments showed activation and inhibition of the enzyme activity when 0.01-5.0 mM of aluminum sulphate were used (IC(50): 1.31 mM). Treatment with citrate and aluminum plus citrate increased ALA-D activity in vivo and the increase in enzyme activity was parallel to the increase in aluminum content in blood and plasma. These results show that aluminum has a distinct effect on ALA-D activity: first, at relatively lower concentrations it activated, and at high concentration it inhibited, blood ALA-D in vitro; second, it activated the enzyme when administered to drinking water. One important toxicological finding of the present report is that the apparent irrelevant addition of citrate to the drinking water significantly increased the level of aluminum in blood and plasma. Thus, in order to predict more accurately the extent of human exposure to aluminum it would be advantageous to consider the level of citrate ingestion and not exclusively the aluminum level in water or food.

Administration, Oral↗