PCWG2 recommends increasing emphasis on time-to-event end points (ie, failure to progress) as decision aids in proceeding from phase II to phase III trials. Recommendations will evolve as data are generated on the utility of intermediate end points to predict clinical benefit.

For two series of polyethylenimine-graft-poly(ethylene glycol) (PEI-g-PEG) block copolymers, the influence of copolymer structure on DNA complexation was investigated and physicochemical properties of these complexes were compared with the results of blood compatibility, cytotoxicity, and transfection activity assays. In the first series, PEI (25 kDa) was grafted to different degrees of substitution with PEG (5 kDa) and in the second series the molecular weight (MW) of PEG was varied (550 Da to 20 kDa). Using atomic force microscopy, we found that the copolymer block structure strongly influenced the DNA complex size and morphology: PEG 5 kDa significantly reduced the diameter of the spherical complexes from 142 +/- 59 to 61 +/- 28 nm. With increasing degree of PEG grafting, complexation of DNA was impeded and complexes lost their spherical shape. Copolymers with PEG 20 kDa yielded small, compact complexes with DNA (51 +/- 23 nm) whereas copolymers with PEG 550 Da resulted in large and diffuse structures (130 +/- 60 nm). The zeta-potential of complexes was reduced with increasing degree of PEG grafting if MW >or= 5 kDa. PEG 550 Da did not shield positive charges of PEI sufficiently leading to hemolysis and erythrocyte aggregation. Cytotoxicity (lactate dehydrogenase assay) was independent of MW of PEG but affected by the degree of PEG substitution: all copolymers with more than six PEG blocks formed DNA complexes of low toxicity. Finally, transfection efficiency of the complexes was studied. The combination of large particles, low toxicity, and high positive surface charge as in the case of copolymers with many PEG 550 Da blocks proved to be most efficient for in vitro gene transfer. To conclude, the degree of PEGylation and the MW of PEG were found to strongly influence DNA condensation of PEI and therefore also affect the biological activity of the PEI-g-PEG/DNA complexes. These results provide a basis for the rational design of block copolymer gene delivery systems.

No abstract

This is a review article of the wide-awake approach to hand surgery. More than 95% of all hand surgery can now be performed without a tourniquet. Epinephrine is injected with lidocaine for hemostasis and anesthesia instead of a tourniquet and sedation. This is sedation-free surgery, much like a visit to a dental office. The myth of danger of using epinephrine in the finger is reviewed. The wide awake technique is greatly improving results in tendon repair, tenolysis, and tendon transfer. Here, we will explain its advantages.

Traditionally, surgeons were taught that local anesthesia containing epinephrine should not be injected into fingers. This idea has since been refuted in many basic and clinical scientific studies, and today, injection of lidocaine plus epinephrine is widely used for digital and hand anesthesia in Canada. The key advantages of the wide-awake technique include the creation of a bloodless field without the use of an arm tourniquet, which in turn reduces the need for conscious sedation. The use of local anesthesia permits active motion intraoperatively, which is particularly helpful in tenolysis, flexor tendon repairs, and setting the tension on tendon transfers. Additional benefits of wide-awake anesthesia include efficiencies and cost savings in outpatient surgical case flow due to the absence of conscious sedation.

Star-shaped poly(ethylene glycol)-block-polyethylenimine [star-(PEG-b-PEI)] significantly enhance plasmid DNA condensation of low molecular weight (MW) PEIs. The star-block copolymers were prepared via a facile synthesis route using hexamethylene diisocyanate as linker between PEG and PEI blocks. NMR and FT-IR spectroscopy confirmed the structures of intermediately activated PEG and final products. Furthermore, the copolymers were characterized by size exclusion chromatography, static light scattering, and viscosimetry. Their molecular weights (M(w) 19-26 kDa) were similar to high MW PEI (25 kDa). Thermoanalytical investigations (thermogravimetric analysis, differential scanning calorimetry) were also performed and verified successful copolymer synthesis. DNA condensation with the low MW PEIs (800 and 2000 Da) and their 4- and 8-star-block copolymers was studied using atomic force microscopy, dynamic light scattering, zeta-potential measurements, and ethidium bromide (EtBr) exclusion assay. It was found that low MW PEIs formed huge aggregates (500 nm to 2 microm) in which DNA is only loosely condensed. By contrast, the star-block copolymers yielded small (80-110 nm), spherical and compact complexes that were stable against aggregation even at high ionic strength and charge neutrality. Furthermore, as revealed in the EtBr exclusion assay these star-block copolymers exhibited a DNA condensation potential as high as high MW PEI. Since these star-(PEG-block-PEI) copolymers are composed of relatively nontoxic low MW PEI and biocompatible PEG, their potential as gene delivery agents merits further investigations.

No abstract

A major challenge in the development of anticancer therapies is the considerable time and resources needed for conducting randomized clinical trials (RCT). There is a need for more efficient RCT designs that accelerate development, minimize costs, and make trials more appealing to patients.We review the statistical and logistical characteristics of multi-arm designs that compare several experimental treatments to a common control arm. In particular, we present a rationale for not requiring multiplicity adjustment in multi-arm trials that are designed for logistical efficiency. Relative to conducting separate RCTs for each experimental agent, this multi-arm design is shown to require a lower total sample size than multiple two-arm trials.