GSH-responsive poly-resveratrol based nanoparticles for effective drug delivery and reversing multidrug resistance.

Cancer poses a serious threat to human health and is the most common cause of human death. Polymer-based nanomedicines are presently used to enhance the treatment effectiveness and decrease the systemic toxicity of chemotherapeutic agents. However, the disadvantage of currently polymeric carriers is without therapy procedure. Herein, for the first time, glutathione (GSH)-responsive polymer (PRES) with anti-cancer effect was synthesized following the condensation-polymerization method using resveratrol (RES) and 3,3'-dithiodipropionic acid. PRES can not only suppress the tumor cells growth but can also self-assemble into nanoparticles (∼93 nm) for delivering antitumor drugs, such as paclitaxel (PTX@PRES NPs). The system could achieve high drug loading (∼7%) and overcome multidrug resistance (MDR). The results from the in vitro studies revealed that the NPs formed of PRES were stable in the systemic circulation, while could be efficiently degraded in tumor cells high GSH environment. Results from cytotoxicity tests confirmed that PTX@PRES NPs could effectively suppress the growth of cancer cells (A549) and drug-resistant cells (A549/PTX). The NPs could also be used to significantly increase the therapeutic efficacy of the drugs in A549/PTX tumor-bearing mice. In vivo investigations also demonstrated that the PRES-based NPs exhibited tumor inhibition effects. In summary, we report that the GSH-responsive polymer synthesized by us exhibited multiple interesting functions and could be used for effective drug delivery. The polymer exhibited good therapeutic effects and could be used to overcome MDR. Thus, the synthesized system can be used to develop a new strategy for treating cancer.

Effects of biofilm on metal adsorption behavior and microbial community of microplastics.

In this study, the adsorption behavior of Cu(II) and Pb(II) on the biofilm-developed polystyrene (PS) microplastics (MPs) was compared with the virgin PS (V-PS) and UV-aged PS (UV-PS). The results demonstrated that the biofilm could enhance the adsorption abilities onto MPs more than UV radiation. The intra-particle diffusion model suggested that the adsorption on V-PS was dominated by intra-particle diffusion, while the adsorption rate was controlled by the binding diffusion on UV-PS and biofilm-developed PS (Bio-PS). Compared with the V-PS and UV-PS, the Bio-PS showed the largest adsorption capacity based on the Freundlich isotherm model, which indicated that the adsorption of heavy metals onto Bio-PS was multilayer and heterogeneous. The adsorption mechanism of Bio-PS contained physical adsorption, chemisorption, and biosorption. These Bio-PS adsorption types participated in both oxygen and nitrogen groups. Based on the 16S rRNA analysis, the diversity of the microbial community with biofilm changed to a certain extent after the adsorption of heavy metals. Furthermore, the stress of lead (Pb) adsorption had a higher impact on the microbial community distribution and the PS biofilm. This study illustrated how the formation of biofilms can highly affect the adsorption behavior of MPs as well as the microbial community of MPs.

Route of administration of exogenous progesterone for luteal support does not significantly affect the serum concentration in assisted reproductive technology.

The objective of this research is to study the guiding role of serum progesterone level on exogenous luteal support protocols. In the retrospective study, a total of 537 infertile women undergoing IVF/ICSI were recruited. Serum samples were obtained for serum progesterone measurements. The results demonstrated that the progesterone levels of all women gradually decreased over the course of 7 days after ET. The progesterone level of the pregnant women reached a nadir on day 7 after ET and subsequently began to rise, while the progesterone level of the non-pregnant women continued to decrease. Even with different routes of administration of exogenous progesterone, the progesterone levels followed the same patterns. The serum progesterone level does not represent the adequacy of exogenous progesterone supplementation. Therefore, there is no need to measure serum progesterone levels frequently after embryo transfer or adjust the dose according to serum progesterone levels.

[Bacterial diversity in the oral cavity of adolescents with different caries susceptibilities].

OBJECTIVE: To analyze the differences between the bacterial diversities in the saliva of caries-free and caries-susceptible adolescents through polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE). METHODS: Twenty adolescent subjects aged 12-18 years were recruited and subdivided into two groups: caries-free adolescents (n = 10) and caries-susceptible adolescents (n = 10). Saliva samples were collected. Total DNA was isolated directly from each sample. A portion of the 16S rRNA gene locus was PCR-amplified by using universal primers. Microbial diversity was analyzed through PCR-DGGE. RESULTS: Analyzing the DGGE profile, we found that the composition of the saliva microbiome exhibited great intra-individual differences; the average band numbers of the caries-free adolescent group and the caries-susceptible adolescent group were 32.5 ± 3.7 and 27.3 ± 3.4, respectively. The differences between the groups were statistically significant (P = 0.008). Shannon-Wiener's indexes of the caries-susceptible adolescent group and the caries-free adolescent group were 2.5 ± 0.2 and 2.6 ± 0.2, respectively, but the differences between the groups were not significant (P = 0.405). Clustering analysis results suggested that most of the samples in the same group clustered together; this observation showed a high community structure similarity. CONCLUSION: The microbial diversity and complexity of bacteria in saliva are significantly higher in caries-free adolescents than in caries-susceptible adolescents. During caries development, bacterial diversity in the saliva likely decreases.