Photophysical Exploration of Zn(II) Polypyridine Photosensitizers in Two-Photon Photodynamic Therapy: Insights from Theory.

The high incidence and difficulties of treatment of cancer have always been a challenge for mankind. Two-photon photodynamic therapy (TP-PDT) as a less invasive technique provides a new perspective for tumor treatment due to its low-energy near-infrared excitation, high targeting, and minor damage. At present, the emerging metal complexes used as the photosensitizers (PSs) in TP-PDT have aroused great interest. However, most metal complexes as PSs in TP-PDT still face some problems, such as slow clearance, unsatisfactory two-photon absorption (TPA) characteristics, high price, low reactivity, and poor solubility. In this work, density functional theory and time-dependent density functional theory were used to characterize the one/two-photon response, solvation free energy, and lipophilicity of a series of novel PSs applied in TP-PDT. The results suggest that based on complex 1, replacing Ru(II) center with Zn(II) (complex 2) can effectively prolong the triplet excited state lifetime while reducing the cost and environmental pollution, and the azetidine heterospirocycles were introduced into the ligand scaffold (complex 3), which effectively reduced the vibration relaxation of the ligand group and improved the water solubility; further, the addition of acetylenyl groups subtly enhanced the light absorption and significantly improved the two-photon response (complex 4). In addition, all complexes met the requirement of a PS and could be used as potential candidates for TP-PDT. In particular, complex 4 has the advantages of high solvation free energy, a large TPA cross-section (1413 GM), a long triplet state lifetime (671 µs), good chemical reactivity, and low cost, and it is easy to be scavenged by organisms. Overall, this contribution may provide an important clue to formulate clear design principles for type I/II PSs and rational design of PSs with high intersystem crossing rates, a long lifetime, and therapeutic excitation wavelengths.

A Theoretical Investigation into the Homo- and Hetero-leptic Cu(I) Phosphorescent Complexes Bearing 2,9-dimethyl-1,10-phenanthroline and bis [2-(diphenylphosphino)phenyl]ether Ligand.

Cu(I) complexes have received widespread attention as a promising alternative to traditional noble-metal complexes. Herein, we systematically study the properties of Cu(I) complexes from homo- to hetero-ligands, and found the following: (1) hetero-ligands are beneficial to regulate phosphorescent efficiency; (2) when the hetero-ligands in a tetracoordinated Cu(I) complex are 1:1, the ligands coordinate along the dx2-y2 direction of Cu(I) ion, which can observably suppress structural deformation; (3) unlike the P^P ligand, the N^N ligand can enhance the participation of Cu(I) during the transition process; (4) the addition of an appropriate amount of P^P ligand can effectively raise the energy level of HOMO (highest occupied molecular orbital), enhance the proportion of LLCT (ligand-ligand charge transfer), and thereby increase the available singlet emission transition moments which can be borrowed, thus promoting the radiative decay process. As a result, this work provides a detailed understanding of the effects of different ligands in Cu(I) complexes, and provides a valuable reference and theoretical basis for regulating and designing the phosphorescent properties of Cu(I) complexes in the future.

Proximal gastrectomy versus total gastrectomy for proximal gastric carcinoma. A meta-analysis on postoperative complications, 5-year survival, and recurrence rate.

OBJECTIVE: To compare proximal gastrectomy (PG) with total gastrectomy (TG) for proximal gastric carcinoma, through the 5-year survival rate, recurrence rate, postoperative complications, and long-term life quality. METHODS: The meta-analysis was carried out in the General Surgery Department of the Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China. We searched Medline, EMBASE, and the Cochrane Library from June to November 2012. The literature searches were carried out using medical subject headings and free-text word: `proximal gastrectomy` `total gastrectomy` `partial gastrectomy` `stomach neoplasms` and `gastric cancer`. Two different reviewers carried out the search and evaluated studies independently. RESULTS: Two randomized controlled trials and 9 retrospective studies were included. A total of 1364 patients were included in our study. Our analysis showed that there is no statistically significant difference in 5-year survival rate between PG and TG (60.9% versus 64.4%). But, the recurrence is higher in the PG group than the TG (38.7% versus 24.4%). The anastomotic stenosis rate is also higher in the PG than the TG (27.4% versus 7.4%). CONCLUSION: Proximal gastrectomy is an option for upper third gastric cancer in terms of safety. However, it is associated with high risk of reflux symptoms and anastomotic stenosis. Therefore, TG should be the first choice for proximal gastric cancer to prevent reflux symptoms.

[Correlation of single nucleotide polymorphisms of X-ray repair cross complementing group 1 gene to hereditary susceptibility of colorectal cancer].

OBJECTIVE: To investigate the correlation of single nucleotide polymorphisms (SNP) of XRCC1 gene to hereditary susceptibility of colorectal cancer. METHODS: XRCC1 genotypes in 124 colorectal cancer patients and 214 matched healthy people as control were analyzed by SnaP Shot SNP-typing technique. Five different inheritance models including codominant, dominant, recessive, overdominant and log-additive were analyzed using logistic regression model. The haplotype distribution was estimated with phase and its correlation with the risk of colorectal cancer was evaluated. RESULTS: The frequencies of mutant 25487G-A, 25489C-T and 1799782C-T alleles were 0.20, 0.11, 0.32 respectively in the patients, and 0.23, 0.13, 0.34 in the controls. There was no significant correlation of polymophisms of XRCC1 gene to the risk of colorectal cancer in 5 different inheritance models (P>0.05). GCT, GCC, ACC and GTC were the most common haplotypes and the odds ratios were 1, 1.35, 0.90 and 0.84 respectively. There was no significant difference of distribution between 2 groups in haplotypes. CONCLUSION: Polymorphisms of XRCC1 gene, including rs25487, rs25489, rs1799782, are not associated with to the risk of colorectal cancer.