Fine-Tuning the Linear Release Rate of Paclitaxel-Bearing Supramolecular Filament Hydrogels through Molecular Engineering

One key design feature in the development of any local drug delivery system is the controlled release of therapeutic agents over a certain period of time. In this context, we report the characteristic feature of a supramolecular filament hydrogel system that enables a linear and sustainable drug release over the period of several months. Through covalent linkage with a short peptide sequence, we are able to convert an anticancer drug, paclitaxel (PTX), to a class of prodrug hydrogelators with varying critical gelation concentrations. These self-assembling PTX prodrugs associate into filamentous nanostructures in aqueous conditions and consequently percolate into a supramolecular filament network in the presence of appropriate counterions. The intriguing linear drug release profile is rooted in the supramolecular nature of the self-assembling filaments which maintain a constant monomer concentration at the gelation conditions. We found that molecular engineering of the prodrug design, such as varying the number of oppositely charged amino acids or through the incorporation of hydrophobic segments, allows for the fine-tuning of the PTX linear release rate. In cell studies, these PTX prodrugs can exert effective cytotoxicity against glioblastoma cell lines and also primary brain cancer cells derived from patients and show enhanced tumor penetration in a cancer spheroid model. We believe this drug-bearing hydrogel platform offers an exciting opportunity for the local treatment of human diseases.

Cellular immunity in systemic lupus erythematosus as evidenced in vitro by leucocyte migration inhibition tests

A leucocyte migration inhibition test was performed on 26 patients with systemic lupus erythematosus (SLE) and on 35 control subjects using three different antigens, fetal calf thymus DNA, baker's yeast RNA, and calf thymus extractable nuclear antigen (ENA). Leucocyte migration was inhibited by DNA in 17 out of 26 SLE patients (65-3%), and in only 2 of the 35 controls (5-7%). When RNA or ENA was added none of the patients or controls showed inhibition. In SLE patients migration inhibition by DNA was significantly correlated with the presence of proteinuria and/or granular casts in urinary sediment. When the migration inhibition test was positive, immunofluorescence verified active histology of the glomeruli obtained by a percutaneous renal biopsy.

Isotonic Saline Nebulization and Lung Function in Children With Mild Respiratory Ailments

Nebulization with saline solution, although commonly used to alleviate respiratory symptoms, particularly in children, is often questioned concerning its effectiveness. In this study, we investigated the effects of isotonic saline nebulization on lung function in 40 children (mean age of 14±1 years) suffering from different types of airway disorders. Measurements were carried out directly before and up to 15 min after nebulization, for six days in a row, always on the same day time in the morning. The children were divided into two study groups according to the baseline ratio of forced expired volume in one second/forced vital capacity (FEV1/FVC), below and above 80 %. We found significant improvements after saline nebulization in FEV1, mid-expiratory flow at 50 % and 75 % of FVC (MEF50 and MEF75), and peak expiratory flow (PEF) in the group with the baseline FEV1/FVC less than 80 %. In contradistinction, children with an index greater than 80 % displayed no appreciable changes in the lung function variables when compared with the baseline level before saline nebulization. We conclude that isotonic saline nebulization might mitigate the functional signs of threatening pulmonary obstruction and as such may be clinically useful in pediatric patients with mild respiratory problems.