Hydrophilic, Porous, Fiber-Reinforced Collagen-Based Membrane for Corneal Repair.

Collagen membrane with outstanding biocompatibility exhibits immense potential in the field of corneal repair and reconstruction, but the poor mechanical properties limit its clinical application. Polycaprolactone (PCL) is a biodegradable polymer widely explored for application in corneal reconstruction due to its excellent mechanical properties, biocompatibility, easy processability, and flexibility. In this study, a PCL/collagen composite membrane with reinforced mechanical properties is developed. The membrane has a strong composite structure with collagen by utilizing a porous and hydrophilic PCL scaffold, maintaining its integrity even after immersion. The suture retention and mechanical tests demonstrate that compared with the pure collagen membrane, the prepared membrane has a greater tensile strength and twice the modulus of elasticity. Further, the suture retention strength is improved by almost two times. In addition, the membrane remains fully intact on the implant bed in an in vitro corneal defect model. Moreover, the membrane can be tightly sutured to a rabbit corneal defect, progressively achieve epithelialization, and remain unchanged during observation. Overall, the PCL/collagen composite membrane is a promising candidate as a suturable corneal restoration material in clinical keratoplasty.

The investigation of the ultrafast excited state deactivation mechanisms for coumarin 307 in different solvents.

The intramolecular charge transfer (ICT) and twisted intramolecular charge transfer (TICT) processes of coumarin 307 (C307) in different solvents were investigated by performing steady-state/time-resolved transient absorption spectroscopic and steady-state photoluminescence spectroscopic characterizations in combination with time-dependent density functional theoretical calculation (TDDFT). The study unveiled the remarkable influence of solvent polarity and the strength of intermolecular hydrogen bonds formed between the solutes and solvents on the relaxation dynamics of the electronic excited state. Significantly, the emergence of the TICT state was observed in polar solvents, specifically dimethylformamide (DMF) and dimethyl sulfoxidemethanol (DMSO), owing to their inherent polarity as well as the enhanced intermolecular hydrogen bonding interactions. Interestingly, even in a weak polar solvent such as methanol (MeOH), the TICT state was also observed due to the intensified hydrogen bonding effects. Conversely, nonpolar solvents, exemplified by 1,4-dioxane (Diox), resulted in the stabilization of the ICT state due to the augmented N-H⋯O hydrogen bonding interactions. The experimental findings were corroborated by the computational calculations, thus ensuring the reliability of the conclusions drawn. Furthermore, schematic diagrams were presented to illustrate the mechanisms underlying the excited-state deactivation. Overall, this investigation contributes valuable mechanistic insights and provides a comprehensive understanding of the photochemical and photophysical properties exhibited by coumarin dyes.

[Expressions of OCT4 and CD133 and their correlation in colonic cancer].

OBJECTIVE: To investigate the expressions of Oct4 and CD133 and their correlation in colonic cancer. METHODS: The expression of Oct4 and CD133 were detected by immunohistochemistry in 30 colon cancer specimens and the paired adjacent tissues. RESULTS: The positivity rates of Oct4 and CD133 expression were 83.3% (25/30) and 73.3% (22/30) in colonic cancer tissue, respectively, and their expressions were positively correlated (r=0.586, P<0.05). The matched adjacent tissues showed significantly lower levels of Oct4 and CD133 expressions (P<0.01). CONCLUSION: The expressions of Oct4 and CD133 are upregulated in colonic cancer compared with those in the adjacent tissues and show a positive correlation. Oct4 and CD133 may play an important role in the development of colon cancer.

[A case control study on the impact of CYP450 MSPI and GST-M1 polymorphisms on the risk of lung cancer].

OBJECTIVE: To study the correlation of polymorphisms of CYP1A1 MSPI and glutathiones S-transferase (GST-M1) independently and in combination with the risk of lung cancer. METHODS: A case control study which included 91 cases of lung cancer and 138 controls collected from the First Affiliated Hospital of Sun Yat-sen University of Medical Sciences, Guangzhou Tumor Hospital and The Red Cross Hospital of Guangzhou or conmunity area. All subjects were investigated with a uniform questionnaire. Blood samples were collected from all cases and controls for detecting CYP1A1 MSPI and GST-M1 polymorphisms which were analyzed by PCR and RFLP. RESULTS: It showed that there was no significant difference in frequencies of this genotypes of CYP1A1 MSPI between the two groups. The frequency of GST-M1 null (0/0) genotype was higher in the case group than in the control group, with an OR of 1.38 (95% CI 0.81 - 2.38), but there was no statistical significance. However, combination of several genotypes was strongly associated with lung cancer. There was a synergistic interaction between the m2m2 genotype of CYP1A1 MSPI and GST-M1 (0/0) genotype, with an OR of 2.47 (95% CI 1.03 - 5.90). CONCLUSION: The combination of two genetic polymorphisms significantly increases the risk of lung cancer.