Gold@Silver@Gold Core Double-Shell Nanoparticles: Synthesis and Aggregation-Enhanced Two-Photon Photoluminescence Evaluation

A facile, straightforward, and low-cost method is proposed to synthesize gold@silver@gold core double-shell nanoparticles. The technique is a seed-mediated growth protocol that contains four steps of (1) gold seed synthesis, (2) gold seed growth, (3) silver layer coating through silver salt reduction, and (4) gold layer deposition via gold precursor reduction. The prepared nanoparticles had a narrow size distribution and the average particle size of 28 ± 1 nm. Cysteine was introduced to the nanoparticles solution as a coupling agent to assemble nanoparticles. Aggregation-induced two-photon photoluminescence enhancement of three types assembled nanoparticles, i.e., gold@silver@gold, gold@silver, and gold nanoparticles, was studied. It was observed that the assembled core double-shell nanoparticles presented huge enhancement in two-photon photoluminescence signal in comparison with two other nanoparticles. Moreover, the gold@silver@gold nanoparticle is a stable and biocompatible plasmonic nanosystem. This paper provides a novel candidate for two-photon photoluminescence excitation sensing and imaging for biomedical applications.

     

Effects of shoot and root application of thiamin on salt-stressed sunflower plants

Plants of sunflower (Helianthus annuus L. cv Giza2) were salt-stressed with a combination of NaCl and CaCl₂ inconcentrations having different osmotic potentials (s from 0 to –1.0MPa) and were treated with 5 and 10mg L^–1 of thiamin either sprayed on the shoot orapplied to the root. The membranes of leaf discs from salt-stressed plantsappeared to be less stable (more injured) under heat(51°C) and drought (40% polyethylene glycol6000) stresses than control plants. Salinity slowed the rate of growth (lengthand dry mass production), lowered leaf relative water content (RWC) and leafandroot water potential (w), decreased the contents of chlorophyll (Chl),soluble sugars (SS) and the K⁺/Na⁺ ratio butenhanced total free amino acids (TAA), Na⁺,Ca²⁺and Cl^– accumulation in the shoot and root system. Root orshoot application of thiamin reduced membrane injury by either heat ordehydration stress, lowered leaf w, improved uptake of K⁺,and increased leaf RWC, Chl, SS, TAA contents and dry mass production. Theeffects of salinity (s), thiamin (Thi.) and their interaction(s×Thi) on the parameters tested were significant.Salinity was dominant (as indicated by ² values) in affectingthe contents of Ca²⁺, Cl^–, TAA and membranestability to heat and leaf w. The role of thiamin was dominant forNa⁺, K⁺ and SS contents and the contribution ofinteraction was dominant for growth parameters, Chl. and root w.     

Chemopreventive activity of selenocysteine prodrugs against tobacco‐derived nitrosamine (NNK) induced lung tumors in the A/J mouse

Prodrugs of L ‐selenocysteine have potential utility in cancer chemoprevention. This study reports the efficacy of three selenazolidine‐4(R)‐carboxylic acids, (2‐unsubstituted, 2‐oxo, and 2‐methyl derivatives; SCA, OSCA, and MSCA, respectively) against tobacco‐related lung tumorigenesis in a mouse model. Seven days after initiation of an AIN‐76A diet supplemented with sodium selenite (5 ppm Se), L ‐selenomethionine (3.75 ppm Se), Se‐methyl‐L ‐selenocysteine (3 ppm Se), L ‐selenocystine (15 ppm Se), SCA (15 ppm Se), OSCA (15 ppm Se), or MSCA (15 ppm Se), mice received 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK; 10 μmol, i.p.). After an additional 16 weeks on the diets, two compounds, OSCA and selenocystine, significantly reduced lung adenoma multiplicity from 7.2 tumors per mouse in the NNK group to 4.5 and 4.6 tumors per mouse, respectively. Neither selenium concentration nor glutathione peroxidase activity in either RBCs or liver served as surrogate indicators of tumor reduction. Hepatic selenium levels were significantly elevated by all selenium‐containing compounds except Se‐methyl‐L ‐selenocysteine and SCA; RBC selenium levels by all except sodium selenite and MSCA. With the exception of L ‐selenomethionine, RBC glutathione peroxidase activity was increased along with the elevated selenium levels. Hepatic glutathione peroxidase activity was elevated by all Se‐compounds except SCA. The two compounds showing significant tumor reduction (OSCA and selenocystine) were the only two compounds that showed ubiquity of changes, elevating both selenium levels and GPx activity in both liver and RBC. © 2005 Wiley Periodicals, Inc. J Biochem Mol Toxicol 19:396‐405, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/jbt.20105     

Hairy root culture optimization and resveratrol production from <Emphasis Type="Italic">Vitis vinifera</Emphasis> subsp. <Emphasis Type="Italic">sylvesteris</Emphasis>

Resveratrol is a polyphenolic compound produced in very low levels in grapes. To achieve high yield of resveratrol in wild grape, three Agrobacterium rhizogenes strains, Ar318, ArA4 and LBA9402, were used to induce hairy roots following infection of internodes, nodes or petioles of in vitro grown Vitis vinifera subsp. sylvesteris accessions W2 and W16, and cultivar Rasha. The effects of inoculation time, age of explants, bacterial concentration and co-cultivation times were examined on the efficiency of the production of hairy roots. Strains Ar318, ArA4 and LBA9402 all induced hairy roots in the tested genotypes, but the efficiency of ArA4 strain was higher than the other strains. The highest hairy root production was with using internodes as explants. The transformation of hairy roots lines was confirmed by PCR detection of rolB gene. Half Murashige and Skoog (MS) medium was better for biomass production compared with MS medium. HPLC analysis of resveratrol production in the hairy root cultures showed that all the genotypes produced higher amounts of resveratrol than control roots. The highest amount of resveratrol was produced from W16 internode cultures, which was 31-fold higher than that of control root. Furthermore, TLC analysis showed that treatments of hairy roots with sodium acetate and jasmonate elevated resveratrol levels both in hairy root tissue and excreted into the half MS medium. These results demonstrate that endogenous and exogenous factors can affect resveratrol production in hairy root culture of grape, and this strategy could be used to increase low resveratrol production in grapes.     

Effects of lead and kinetin on the growth, and some physiological components of safflower

Pollution of the root environment with excess of Pb retarded shoot growth, decreased chlorophyll (Chl) content and reduced Chl stability (CSI) to heat. Plants growing in Pb polluted soil accumulated much more free amino acids and less soluble sugars than the control plants. Stability of leaf membranes to heat (51 °C) or dehydration stresses (40% polyethylene glycol, 6000) decreased in response to Pb pollution where the membranes of leaf discs excised from Pb-treated plants were damaged more than those taken from plants growing in Pb free soil. Supplying kinetin ameliorated the deleterious effects of Pb pollution on the parameters tested. Kinetin-treated plants had higher Chl, soluble sugars content and produced more biomass in their shoots. Also, kinetin increased leaf membrane stability especially in Pb-treated plants, effectively protected chlorophyll degradation by heat and increased Chl a and b stability index; the most effective concentration was 10 mg L^–1. The effects of Pb and kinetin as well as their interaction (Pb × Kin) on the parameters tested were statistically significant. Applied kinetin had a dominant role (as indicated by ²) in affecting shoot growth, soluble sugars, Chl a and b contents, stability of leaf membranes to dehydration stress as well as the Chl stability index. Pb had a dominant role on total free amino acids (TAA) and leaf relative water content (RWC). The interaction between Kin × Pb influenced the stability of leaf membranes to heat stress in a major way.     

Oxidative Stress in Skin Fibroblasts Cultures of Patients with Huntington’s Disease

Oxidative stress and mitochondrial dysfunction should play a role in the neurodegeneration in Huntington’s disease (HD). The most consistent finding is decreased activity of the mitochondrial complexes II/III and IV of the respiratory chain in the striatum. We assessed enzymatic activities of respiratory chain enzymes and other enzymes involved in oxidative processes in skin fibroblasts cultures of patients with HD. We studied respiratory chain enzyme activities, activities of total, Cu/Zn- and Mn-superoxide-dismutase, glutathione-peroxidase (GPx) and catalase, and coenzyme Q₁₀ (CoQ₁₀) levels in skin fibroblasts cultures from 13 HD patients and 13 age- and sex-matched healthy controls. When compared with controls, HD patients showed significantly lower specific activities for catalase corrected by protein concentrations (P < 0.01). Oxidized, reduced and total CoQ₁₀ levels (both corrected by citrate synthase (CS) and protein concentrations), and activities of total, Cu/Zn- and Mn-superoxide-dismutase, and gluthatione-peroxidase, did not differ significantly between HD-patients and control groups. Values for enzyme activities in the HD group did not correlate with age at onset and of the disease and with the CAG triplet repeats. The primary finding of this study was the decreased activity of catalase in HD patients, suggesting a possible contribution of catalase, but not of other enzymes related with oxidative stress, to the pathogenesis of this disease.     

Thymol and Carvacrol Prevent Doxorubicin‐Induced Cardiotoxicity by Abrogation of Oxidative Stress,Inflammation, and Apoptosis in Rats

The aim of this study was to assess the possible protective effects of thymol and carvacrol (CAR) against doxorubicin (DOX)‐induced cardiotoxicity. A single dose of DOX (10 mg/kg i.v.) injected to male rats revealed significant increases in serum lactate dehydrogenase, creatine kinase, creatine kinase isoenzyme‐MB, aspartate transaminase, tumor necrosis factor‐alpha, and cardiac troponin levels. It also increased heart contents of malondialdehyde and caspase‐3 accompanied by a significant reduction in heart content of reduced glutathione as well as catalase and superoxide dismutase activity as compared with the control group. In contrast, administration of thymol (20 mg/kg p.o.) and/or CAR (25 mg/kg p.o.) for 14 days before DOX administration and for 2 days after DOX injection ameliorated the heart function and oxidative stress parameters. Summarily, thymol was more cardioprotective than CAR. Moreover, a combination of thymol and CAR had a synergistic cardioprotective effect that might be attributed to antioxidant, anti‐inflammatory, and antiapoptotic activities.     

MMP‐2 and MMP‐9 as prognostic markers for the early detection of urinary bladder cancer

The present study assessed protein and gene expression levels of tissue inhibitor of metalloproteinase‐2 (TIMP‐2), matrix metalloproteinase‐2 (MMP‐2), and MMP‐9 in urine and blood samples of 50 patients with bladder carcinoma. The expression of TIMP‐2, MMP‐2, and MMP‐9 levels with tumor stage and grade was also assessed. Results showed that the expression levels of MMP‐2 and MMP‐9 in both blood and urine were significantly elevated in group 1 when compared with groups 2 and 3 healthy subjects. The discriminatory ability in the diagnosis of bladder carcinoma of MMP‐2 and MMP‐9 expression was confirmed by receiver operating characteristic curve analysis that revealed a sensitivity and specificity of 100%. MMP‐2 and MMP‐9 levels were not correlated with grade or stage of the tumor. With respect to TIMP‐2 blood and urine levels, results showed a significant decrease in gene expression levels in bladder carcinoma group, whereas, TIMP‐2 protein showed a significant increase in bladder carcinoma.     

Utilization of erythrosine B in spectrofluorimetric quenching analysis of amlodipine and perindopril in pharmaceutical and biological matrices

A spectrofluorimetric approach that is sensitive, simple, validated, and cost-effective has been proposed for the estimation of amlodipine (AML) and perindopril (PER) in their bulk powders, pharmaceutical formulations, and spiked human plasma. The recommended approach utilized the quantitative quenching effect of the two cited drugs on the fluorescence intensity of erythrosine B, as a result of complex binary reactions among each drug with erythrosine B at pH 3.5 (Teorell and Stenhagen buffer). The quenching of erythrosine B fluorescence was recorded at 554 nm after excitation at 527 nm. The calibration curve was detected in the range 0.25–3.0 μg ml⁻¹, with a correlation coefficient of 0.9996 for AML, and 0.1–1.5 μg ml⁻¹, with a correlation coefficient of 0.9996 for PER. The established spectrofluorimetric approach was validated for the estimation of the cited drugs with high sensitivity regarding International Council on Harmonization guidelines. Therefore, the established approach could be utilized for quality control of the cited drugs in their pharmaceutical formulations.     

Quince (Cydonia oblonga Miller) peel polyphenols modulate LPS-induced inflammation in human THP-1-derived macrophages through NF-κB, p38MAPK and Akt inhibition

Chronic inflammation is a hallmark of several pathologies, such as rheumatoid arthritis, gastritis, inflammatory bowel disease, atherosclerosis and cancer. A wide range of anti-inflammatory chemicals have been used to treat such diseases while presenting high toxicity and numerous side effects. Here, we report the anti-inflammatory effect of a non-toxic, cost-effective natural agent, polyphenolic extract from the Tunisian quince Cydonia oblonga Miller. Lipopolysaccharide (LPS) treatment of human THP-1-derived macrophages induced the secretion of high levels of the pro-inflammatory cytokine TNF-α and the chemokine IL-8, which was inhibited by quince peel polyphenolic extract in a dose-dependent manner. Concomitantly, quince polyphenols enhanced the level of the anti-inflammatory cytokine IL-10 secreted by LPS-treated macrophages. We further demonstrated that the unexpected increase in IL-6 secretion that occurred when quince polyphenols were associated with LPS treatment was partially responsible for the polyphenols-mediated inhibition of TNF-α secretion. Biochemical analysis showed that quince polyphenols extract inhibited the LPS-mediated activation of three major cellular pro-inflammatory effectors, nuclear factor-kappa B (NF-κB), p38MAPK and Akt. Overall, our data indicate that quince peel polyphenolic extract induces a potent anti-inflammatory effect that may prove useful for the treatment of inflammatory diseases and that a quince-rich regimen may help to prevent and improve the treatment of such diseases.