Silk-elastinlike copolymers enhance bioaccumulation of semisynthetic glycosaminoglycan ethers for prevention of radiation induced proctitis

Radiation-induced proctitis (RIP) is a debilitating adverse event that occurs commonly during lower abdominal radiotherapy. The lack of prophylactic treatment strategies leads to diminished patient quality of life, disruption of radiotherapy schedules, and limitation of radiotherapy efficacy due to dose-limiting toxicities. Semisynthetic glycosaminoglycan ethers (SAGE) demonstrate protective effects from RIP. However, low residence time in the rectal tissue limits their utility. We investigated controlled delivery of GM-0111, a SAGE analogue with demonstrated efficacy against RIP, using a series of temperature-responsive polymers to compare how distinct phase change behaviors, mechanical properties and release kinetics influence rectal bioaccumulation. Poly(lactic acid)-co-(glycolic acid)-block-poly(ethylene glycol)-block-poly(lactic acid)-co-(glycolic acid) copolymers underwent macroscopic phase separation, expelling >50% of drug during gelation. Poloxamer compositions released GM-0111 cargo within 1 h, while silk-elastinlike copolymers (SELPs) enabled controlled release over a period of 12 h. Bioaccumulation was evaluated using fluorescence imaging and confocal microscopy. SELP-415K, a SELP analogue with 4 silk units, 15 elastin units, and one elastin unit with lysine residues in the monomer repeats, resulted in the highest rectal bioaccumulation. SELP-415K GM-0111 compositions were then used to provide localized protection from radiation induced tissue damage in a murine model of RIP. Rectal delivery of SAGE using SELP-415K significantly reduced behavioral pain responses, and reduced animal mass loss compared to irradiated controls or treatment with traditional delivery approaches. Histological scoring showed RIP injury was ameliorated for animals treated with GM-0111 delivered by SELP-415K. The enhanced bioaccumulation provided by thermoresponsive SELPs via a liquid to semisolid transition improved rectal delivery of GM-0111 to mice and radioprotection in a RIP model.

Further research on personality dimensions and physical symptoms using the Differential Diagnostic Technique

The personality dynamics using the Differential Diagnostic Technique are delineated as part of an effort to understand their key role underlying the expression of physical symptoms. An urban sample of 40 boys and 71 girls, aged 14 and 15 years old, from regular classrooms completed the Health Survey which taps into five scales of physical symptoms of stress and the Differential Diagnostic Technique. The personality dimensions produced were very similar to those of earlier studies involving a young criminogenic sample. Expected trends for physical symptoms with ego control, rigid defensiveness, and personality organization are reported. This study provided further validity and reliability data for the Differential Diagnostic Technique as a useful instrument for assessing and interpreting the dynamics of human behaviour.