Contact-Killing Antibacterial Polystyrene Polymerized Using a Quaternized Cationic Initiator.

Contact-killing antibacterial materials are attracting attention owing to their ability for sustained antibacterial activity. However, contact-killing antibacterial polystyrene (PS) has not been extensively studied because its chemically stable structure impedes chemical modification. In this study, we developed an antibacterial PS sheet with a contact-killing surface using PS synthesized from 2,2'-azobis-[2-(1,3-dimethyl-4,5-dihydro-1H-imidazol-3-ium-2-yl)]propane triflate (ADIP) as a radical initiator with cationic moieties. The PS sheet synthesized with ADIP (ADIP-PS) exhibited antibacterial activity in contrast to PS synthesized with other azo radical initiators. Surface ζ-potential measurements revealed that only ADIP-PS had a cationic surface, which contributed to its contact-killing antibacterial activity. The ADIP-PS sheets also exhibited antibacterial activity after washing. In contrast, PS sheets containing silver, a typical leachable antibacterial agent, lost all antibacterial activity after the same washing treatment. The antibacterial ADIP-PS sheet demonstrated strong broad-spectrum activity against both Gram-positive and Gram-negative bacteria, including drug-resistant bacteria. Cytotoxicity tests using L929 cells showed that the ADIP-PS sheets were noncytotoxic. This contact-killing antibacterial PS synthesized with ADIP thus demonstrated good prospects as an easily producible antimicrobial material.

Impact of Physical Inactivity on the Risk of Disability and Hospitalization in Older Patients with Advanced Lung Cancer.

PURPOSE: This prospective observational study aimed to explore the influence of physical inactivity during initial chemotherapy on the risk of disability and hospitalization in later life among older patients with advanced non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Patients aged 70 or above who were scheduled to receive first-line chemotherapy for newly diagnosed advanced NSCLC were recruited for the study. An electronic pedometer was used to measure daily steps; based on the change rate (cutoff: -12.5%) from pretreatment to 12 ± 4 weeks after enrolment, patients were classified as active or inactive. The Barthel Index estimated activities of daily living. We compared disability-free survival time, mean cumulative functions of hospital stays, and medical costs, between the active and inactive groups. RESULTS: Among the 29 patients enrolled, 21 were evaluable. Compared with active patients (n = 11), inactive patients (n = 10) showed shorter disability-free survival (6.4 vs 19.9 months, p < 0.05) and tended to have longer hospital stays (23.7 vs 6.3 days/person) and higher inpatient care cost (¥1.6 vs ¥0.3 million/person [US$16,000 vs US$3000/person]) during the first year. CONCLUSION: Physical inactivity during initial chemotherapy may be a risk factor for developing disability and requiring hospitalization in later life for older patients with advanced NSCLC. Our findings may indicate the need for lifestyle interventions with multidisciplinary teams, which include physicians, nurses, and physiotherapists, for older patients with advanced lung cancer during an active cancer treatment. A large-sample-sized study is needed to validate our findings.

Clinical impact of walking capacity on the risk of disability and hospitalizations among elderly patients with advanced lung cancer.

PURPOSE: Little is known about the impact of decreased walking capacity on clinical outcomes in elderly patients with cancer. This prospective observational study aimed to investigate the impact of walking capacity on the risk of disability and hospitalization in elderly patients with advanced lung cancer. METHOD: This study prospectively enrolled 60 patients aged ≥ 70 years with advanced non-small-cell lung cancer (NSCLC) scheduled to receive first-line chemotherapy or radical radiotherapy between January 2013 and December 2014 (trial registration number: UMIN000009768). Patients were classified into the mobile or less mobile group based on the median incremental shuttle walking distance (ISWD) before initial treatment. Assessments included the Barthel index, disability-free survival time, mean cumulative lengths of hospital stay, and inpatient medical costs. RESULTS: The median ISWD was 290 m (interquartile range, 245-357.5 m). The mobile group (ISWD ≥ 290 m) had a longer disability-free survival time than the less mobile group (ISWD < 290 m, 24.6 months vs. 8.4 months, p < 0.05). During the first year from study entry, the mobile group had shorter cumulative lengths of hospital stay (41.3 vs. 72.9 days/person, p < 0.05) and lower inpatient medical costs (¥1.9 vs. ¥2.9 million/person, p < 0.05) than the less mobile group. CONCLUSION: Elderly NSCLC patients with adequate walking capacity showed lower risks of disability, shorter hospitalizations, and lower inpatient medical costs than patients with reduced walking capacity. Further prospective research is needed to validate these findings. The trial was registered with the University Hospital Medical Information Network as trial number UMIN000009768 on January 13, 2013. TRIAL REGISTRATION: UMIN000009768.

Thermo-Responsive Nanocomposite Hydrogels Based on PEG-b-PLGA Diblock Copolymer and Laponite.

Poly(ethylene glycol)-b-poly(d,l-lactide-co-glycolide) (PEG-b-PLGA) diblock copolymers are widely known as polymeric surfactants for biomedical applications, and exhibit high solubility in water compared to PLGA-b-PEG-b-PLGA triblock copolymers known as gelation agents. In order to overcome the difficulties in the preparation of thermo-responsive hydrogels based on PLGA-b-PEG-b-PLGA due to the low solubility in water, the fabrication of thermo-responsive hydrogels based on PEG-b-PLGA with high solubility in water was attempted by adding laponite to the PEG-b-PLGA solution. In detail, PEG-b-PLGA with high solubility in water (i.e., high PEG/PLGA ratio) were synthesized. Then, the nanocomposite solution based on PEG-b-PLGA and laponite (laponite/PEG-b-PLGA nanocomposite) was fabricated by mixing the PEG-b-PLGA solutions and the laponite suspensions. By using the test tube inversion method and dynamic mechanical analysis (DMA), it was found that thermo-responsive hydrogels could be obtained by using PEG-b-PLGA, generally known as polymeric surfactants, and that the gelation temperature was around the physiological temperature and could be regulated by changing the solution composition. Furthermore, from the structural analysis by small angle neutron scattering (SANS), PEG-b-PLGA was confirmed to be on the surface of the laponite platelets, and the thermosensitive PEG-b-PLGA on the laponite surface could trigger the thermo-responsive connection of the preformed laponite network.