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.

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.

Antioxidative Activity of Platinum Nanocolloid and Its Protective Effect Against Chemical-Induced Hepatic Cellular Damage.

Oxidative stress, a major cause of cellular injuries, is closely associated with a variety of chronic diseases such as cancer, liver diseases, degenerative brain disease and aging. In this study, we investigated antioxidant properties of platinum nanocolloid (PNC) against various oxidative stress conditions in vitro/in vivo by treating PNC on liver cell or tissue. Antioxidant activities of the PNC were determined by measuring quenching capacity on reactive oxygen species and its protective action against hydrogen peroxide or CCl4-induced oxidative cellular damage in HepG2 cell or liver tissue of mice. In vitro study, PNC markedly suppressed the production H2O2, ·OH, α,α-diphenyl-ß-picrylhydrazyl radical and nitric oxide in a dose-dependent manner. PNC also inhibited hydrogen peroxide-induced oxidative cellular damage in HepG2 hepatocytes. In vivo study with mice, PNC reduced hepatic lipid peroxidation and CCl4 induced toxicity. Our results support that platinum nanocolloid has antioxidant activities and protects hepatic cellular oxidative damage. Thus platinum nanocolloid may have a potential to be used as an antioxidant supplement.

Research on Nutrition, Dental Caries Status Using Novel Methods, and Related Factors to Preschool Children in Rural Areas of Vietnam.

The study aims to examine correlations between nutrition status with different factors and dental caries of preschool children in rural areas of Vietnam. A big data based on a total of 690 children (356 boys and 334 girls), aged 2-5 years, living in Van Xuan commune, were thoroughly analyzed. Oral examinations were performed by dentists with the assistance of nursery teachers and the research team. Caries was diagnosed using criteria established by the International Caries Detection and Assessment System (ICDAS). The examined children and their parents responded to questions pertaining to dental hygiene practices. The nutrition status of preschool children was determined by the World Health Organization (WHO) standards in 2006. There are factors which have effects on the malnutrition status of children in the research. The prevalence of dental caries also contributed importantly to assess children's development. In this study, the stunting groups have a higher ratio of caries compared to the others. Children's morphology and nutritional status are associated with dental caries among the preschool children in Van Xuan commune, Vinh Tuong district, Vinh Phuc province.

Biological attributes of the kissing bug Triatoma rubrofasciata from Vietnam.

BACKGROUND: Triatoma rubrofasciata is the only kissing bug species distributed globally. In the Americas, this species transmits the parasite Trypanosoma cruzi, responsible for Chagas disease. The presence of T. rubrofasciata in several Asian countries has greatly increased recently. In Vietnam, it is found in large numbers, closely associated with human environments. Although T. rubrofasciata from Asia is not infected with Tryp. cruzi, it carries other parasites such as Trypanosoma lewisi and Trypanosoma conorhini. Reports of bites by T. rubrofasciata have increased significantly in several places of Vietnam, becoming a public health problem as it produces severe anaphylactic reactions. METHODS: Specimens of T. rubrofasciata were collected from seven provinces in central Vietnam. We analyzed different biological attributes (life-cycle, starvation resistance, feeding and reproductive capacities) and genetic characteristics (chromosomes and DNA sequences) of T. rubrofasciata from Vietnam and compared them with Brazilian specimens. Natural infection with Tryp. conorhini and Tryp. lewisi were analyzed in a sample of 100 collected insects. RESULTS: Species identification of T. rubrofasciata from central Vietnam was corroborated by genetic markers. Cytogenetic analyses showed that T. rubrofasciata from central Vietnam share the same chromosomal characteristics with individuals from Brazil and Hanoi. DNA sequence analyses of a mitochondrial cytochrome b gene fragment showed little variation between Old and New World specimens. Our study sample, compared with Brazilian individuals, showed a higher survival capacity revealed by a higher hatching rate (98% compared with 80.5%), a larger amount of blood taken in single meal and long-term starvation resistance. Furthermore, this species had a high natural rate of infection with Tryp. conorhini (46%) and Tryp. lewisi (27%). CONCLUSIONS: For T. rubrofasciata of Vietnam, a high rate of fecundity throughout the year, a high capacity for starvation, and its occurrence in synanthropic environments of urban areas with a high availability of food sources are risk factors to be taken into account by vector control campaigns. The several allergic reactions caused by their bites and their high infection with Tryp. lewisi highlight the need to implement specific control programmes for T. rubrofasciata in Vietnam.

PAMAM dendrimer generation 5-pluronic F127 nanofilm as a matrix for local metronidazole release.

A series of dendrimer G5-pluronic F127 nanofilms (at 1:10, 1:20 and 1:30 mole ratios), loaded with various percent of metronidazole hydrochloride, were prepared by the drug deposition with/without gelatin coating. The nanostructural feature of dendrimer G5-pluronic F127 as a matrix for a sustained drug release was investigated by choosing metronidazole, an antibacterial and antiprotozoal drug as a model drug. The studies on surface morphology, polymer erosion and metronidazole release of the prepared nanofilms revealed unique surface morphology, low film erosion rate and long drug release time. The drug release and the erosion rate of nanofilm were slowed in acidic pH condition and the presence of saliva in medium. The nanofilm of G5-PF127 (1:30 mole ratio) coated with gelatin further prolonged metronidazole release showing G5-PF127 coated with 20% gelatin to be the best suited for a metronidazole release. The nanofilms were stable for up to 9 months at dried condition, while those stored at room temperature with 30% relative humidity were less stable. Our results show that PAMAM dendrimer G5-pluronic F127 nanofilm has a potential to serve as a matrix for the local drug delivery.