Hydrophilic and hydrophobic copolymers of a polyaspartylhydrazide bearing positive charges as vector for gene therapy

BACKGROUND: The design of polymeric vectors for gene delivery provided with specific properties is one of the most critical aspects for a successful gene therapy. These polymers should be biocompatible as well as able to carry efficiently DNA to target tissues and to transfect it into cells. RESULTS: The formation of complexes of poly[(α,β‐asparthylhydrazide)–poly(ethylene glycol)] and poly[(α,β‐asparthylhydrazide)–hexadecylamine] copolymers functionalised with glycidyltrimethylammonium chloride (PAHy–PEG‐GTA and PAHy–C₁₆‐GTA, respectively) with DNA was studied. The effects of the introduction of hydrophilic (PEG) or hydrophobic (C₁₆) moieties on the chains of PAHy–GTA copolymers, such as the stabilising effect on the DNA structure, were evaluated. In particular, we observed a high DNA protection by PAHy–PEG‐GTA copolymers. Degradation studies led us to suppose a particular aqueous conformation of the polyionic complex of PAHy–PEG₂₀₀₀‐GTA in which DNA should be internalised into an inner core surrounded by a PEG hydrophilic shell; while no significant protection was detected with PAHy–C₁₆‐GTA in which DNA should be disposed on the surface of the complex, freely exposed to DNase II action. CONCLUSION: The insertion of PEG or C₁₆ chains into the polymeric structure of PAHy–GTA copolymers changes significantly the DNA complexing and protecting ability of the PAHy–GTA copolymers, showing that hydrophilic and hydrophobic side chains can play a crucial role in supramolecular arrangements of interpolyelectrolyte complexes between DNA and PAHy copolymers. Copyright © 2008 Society of Chemical Industry     

Freeze-Dried Secretome (Lyosecretome) from Mesenchymal Stem/Stromal Cells Promotes the Osteoinductive and Osteoconductive Properties of Titanium Cages

Titanium is one of the most frequently used materials in bone regeneration due to its good biocompatibility, excellent mechanical properties, and great osteogenic performance. However, osseointegration with host tissue is often not definite, which may cause implant failure at times. The present study investigates the capacity of the mesenchymal stem cell (MSC)-secretome, formulated as a ready-to-use and freeze-dried medicinal product (the Lyosecretome), to promote the osteoinductive and osteoconductive properties of titanium cages. In vitro tests were conducted using adipose tissue-derived MSCs seeded on titanium cages with or without Lyosecretome. After 14 days, in the presence of Lyosecretome, significant cell proliferation improvement was observed. Scanning electron microscopy revealed the cytocompatibility of titanium cages: the seeded MSCs showed a spread morphology and an initial formation of filopodia. After 7 days, in the presence of Lyosecretome, more frequent and complex cellular processes forming bridges across the porous surface of the scaffold were revealed. Also, after 14 and 28 days of culturing in osteogenic medium, the amount of mineralized matrix detected by alizarin red was significantly higher when Lyosecretome was used. Finally, improved osteogenesis with Lyosecretome was confirmed by confocal analysis after 28 and 56 days of treatment, and demonstrating the production by osteoblast-differentiated MSCs of osteocalcin, a specific bone matrix protein.     

The relationship between status variables and criminal thinking in an offender population.

The authors examined the relationship between criminal thinking factors of control, cognitive immaturity, and egocentrism, and offender characteristics (i.e., age, education, sentence length, time served, reception of mental health services) in 435 adult male offenders. Results of a canonical correlation analysis identified 1 significant and meaningful relationship between a criminal thinking set containing all 3 factors and an offender characteristic set containing all characteristics except for age. Higher levels of criminal thinking on all 3 factors were associated with more education, longer sentence length, more time served, and lack of reception of mental health services. Implications for providing treatment with offenders that targets reducing criminal recidivism and future directions for investigation into the relationship between dynamic recidivism risk factors and offender characteristics are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Return rate following intake revisited.

Attempted to replicate N. E. Betz and S. L. Shullman's (1979) study that examined the relationship of client and counselor sex, experience level, and type of referral to the return rate of clients after intake interviews. In addition, the effect on return rate of clients referred to another counselor vs those who continued with the counselor at intake and the agreement between client and intake counselor on the nature of the problem were examined. 539 16–65 yr old counseling-center clients participated. Most of the differences related to sex were not significant. No differences were found relating to counselor experience level. Significant differences were found in return rates relating to counselor/client agreement on the nature of the problem and to the decision to keep or refer clients. (7 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)