Protective composite silica/polyelectrolyte shell with enhanced tolerance to harsh acid and alkali conditions.

Here we report a facile method to fabricate composite polymeric/inorgainc shells consisting of poly(allylamine hydrochloride) (PAH)/poly-(sodium 4-styrenesulfonate) (PSS) multilayers strengthed by the in situ formed silica (SiO2) nanoparticles (NPs), achieving an enhanced stability under harsh acidic and basic conditions. While the unsiliconised PAH/PSS multilayers show a pH-dependent stability and permeability, the composite PAH/PSS/SiO2 shells display significantly higher chemical tolerance towards a variety of harsh conditions (1 ≤ pH ≤ 13, high salinity). Upon treatment with either hydrochloric acid (HCl, pH=1) or 0.2 M ethylenediaminetetraacetic acid disodium salt (EDTA, weak acid, chelator), the (PAH/PSS)6/SiO2 shells are able to maintain the integrity of most calcium carbonate (CaCO3) particles, as the shells are tickened and densified by sufficient SiO2 NPs. When treated with NaOH solution at pH=13, the (PAH/PSS)6/SiO2 shells also display an intact morphology and maintain the ability to intercept rhodamin B (Rh-B) molecules, which is quite different to that observed with the unsiliconised (PAH/PSS)6 shells. Ultrasound is proved to rapidly break the composite shells, hence can be used as a potential stimulus to trigger the release of encapsulated substances. All the results demonstrate the fact that the composite (PAH/PSS)6/SiO2 shells have a higher chemical stability, lower permeability for small molecules and a greater sensitivity to ultrasound, which is promising for many applications where protecting the activity of small molecules is required, such as the delivery of encapsulated drugs in an unhindered form to their specific destination within the human body.

Overall Survival of Elderly Patients Having Surgery for Colorectal Cancer Is Comparable to Younger Patients: Results from a South Asian Population.

INTRODUCTION: There has been a continuous debate on whether elderly patients with colorectal cancer (CRC) fair worse. The aim of this study is to assess the thirty-day mortality (TDM) and overall survival (OS) of elderly patients undergoing surgery for CRC. METHOD: OS between two groups (≥70 versus <70 years) having surgery for CRC was analyzed. Demographics, tumour characteristics, and serological markers were considered as independent factors. Multivariable analysis was done using the Cox proportional hazard model. We also compared overall survival in the elderly versus those <60 and <50 years. RESULTS: 477 patients, 160 elderly (55% male; median age 75, range 70-89) and 317 younger patients (49% male; median age 55, range 16 to 69), were studied. Overall survival in CRC patients ≥70 is comparable to <70 (P = 0.45) and <60 years (P = 0.08). Poor OS was observed in the ≥70 versus <50 years (P = 0.03). TDM in the elderly was poor (P < 0.05). Postoperative cardiac complication was the only determinant affecting survival in the elderly (P = 0.01). CONCLUSION: OS in elderly CRC patients having surgery is not worse compared to <70 and <60 years although the TDM was higher. Postoperative cardiac complications significantly affected OS in those ≥70 compared to those <50 years. Chronological age alone should not negatively influence surgical decision-making in the elderly.