Different Cellular Effects of Platinum Nanoparticles on RAW 264.7 Cells.

The cellular effects of platinum nanoparticle (PtNP) and platinum nanocolloid (PtNC) were investigated on murine leukemia Raw 264.7 cells. PtNP induced strong cytotoxic effects on Raw 264.7 cells while PtNC showed only mild cytotoxicity. Dramatic reduction in cell growth and morphological changes were observed for cells treated with PtNPs while PtNC did not show these effects. Both PtNPs and PtNC suppressed nitric oxide production, but PtNPs were superior to PtNC. PtNP strongly suppressed the expression of iNOS, COX-2 proteins and the phosphorylation of AKT on LPS-stimulated Raw 264.7 cells while PtNC showed only weak effects on these proteins. Our data showed that the preparation method of platinum nanoparticles may cause different cellular effects on cell growth and signaling.

Platinum Nanoparticles Induce Apoptosis on Raw 264.7 Macrophage Cells.

The cellular effects of platinum nanoparticles (PNP05, average size of 5 nm, and PNP30, average size of 30 nm) were investigated on murine leukemia Raw 264.7 cells. Cells treated with various concentrations of PNPs showed size-dependent cytotoxicity in an MTT assay with PNP5 of smaller nanoparticles higher toxicity than PNP30. Investigations on cell morphology, Annexin V assay, DNA fragmentation and the activity of caspase-3/-7 showed that PNPs induced apoptosis on Raw 264.7 cells by changing cell morphology and density, increasing cell population in apoptosis and causing nucleus fragmentation. Further study on caspase activity by Western blotting revealed that the apoptosis was induced by the activation of caspase-3 and -7. In addition, PNPs inactivated DNA repair system, generating dose-dependent DNA ladder bands on agarose gel electrophoresis. Taken together, PNPs triggered cytotoxicity on Raw 264.7 cells by suppressing cell growth/survival and inducing apoptosis.

Cellular Effects of Troglitazone on YD15 Tongue Carcinoma Cells

An FDA approved drug for the treatment of type II diabetes, Troglitazone (TRO), a peroxisome proliferator–activated receptor gamma agonist, is withdrawn due to severe idiosyncratic hepatotoxicity. In the search for new applications of TRO, we investigated the cellular effects of TRO on YD15 tongue carcinoma cells. TRO suppressed the growth of YD15 cells in the MTT assay. The inhibition of cell growth was accompanied by the induction of cell cycle arrest at G₀/G₁ and apoptosis, which are confirmed by flow cytometry and western blotting. TRO also suppressed the expression of cell cycle proteins such as cyclin D1, cdk2, cdk4, cyclin B1, cdk1(or cdc2), cyclin E1 and cyclin A. The inhibition of cell cycle proteins was coincident with the up-regulation of p21(CIP1/WAF1) and p27(KIP1). In addition, TRO induces the activation of caspase-3 and caspase-7, as well as the cleavage of PARP. Further, TRO suppressed the expressions of Bcl-2 without affecting the expressions of Bad and Bax. Overall, our data supports that TRO induces cell cycle arrest and apoptosis on YD15 cells.

Preparation and Biophysical Characterization of Poly(amidoamine) Dendrimer-Poly(acrylic acid) Graft.

A series of PAMAM dendrimer generation 5-poly(acrylic acid) grafts were prepared to evaluate the potential use of dendritic grafts as a drug encapsulated nanocarrier. The structural features of the synthesized polymer graft were identified by FT-IR and 1H-NMR spectra and the biophysical properties were characterized by measuring its particle size and zeta potential. The prepared dendrimer G5-PAA grafts had particle size in the range of 600 to 900 nm and the size increased proportionally with the number of PAA on dendrimer surface. The electrostatic property of the dendrimer G5-PAA, carried out by HPLC reversed phase column analysis and the measurement of zeta potential, revealed that both migration time and zeta potential were dependent on the number of grafted PAA. The number of free amino groups on dendrimer G5-PAA, determined quantitatively by fluorescamine assay, was in a reverse order with the reaction mole ratio of dendrimer to PAA. In addition, dendrimer G5-PAA showed a pH-dependent solubility in aqueous solution with characteristic pH region of solubility, depending on the dendrimer generation. The observed biophysical properties indicate that PAMAM dendrimer G5-PAA is promising as a drug encapsulated nanocarrier.

Candida krusei colonization in patients with gastrointestinal diseases.

A total of 135 stomach samples from patients with gastrointestinal diseases and normal controls were examined for Helicobacter pylori infection and Candida colonization. Candida krusei was found in specimens from 20% bleeding, 52% ulcer, and 100% gastritis patients, whereas H. pylori infection rates were 82%, 35% and 30%, respectively, for the same groups of patients. C. krusei was not detected in stomach samples from normal controls.