Serum-resistant lipopolyplexes for gene delivery to liver tumour cells.

In this study, an efficient non-viral gene transfer system has been developed by employing polyethylenimine (PEI 800, 25 and 22kDa) and DOTAP and cholesterol (Chol) as lipids (lipopolyplex), at three different lipid/DNA molar ratios (2/1, 5/1 and 17/1) by using five different protocols of formulation. Condensation assays revealed that PEI of 800, 25 and 22kDa were very effective in condensing plasmid DNA, leading to a complete condensation at N/P ratios above 4. Addition of DOTAP/Chol liposomes did not further condense DNA. Increasing the molar ratio lipid/DNA in the complex resulted in higher positive values of the zeta-potential, while the particle size increased in some protocols, but not in others. High molecular weight PEI (800kDa) used in the formulation of lipopolyplexes lead to a bigger particle size, compared to that obtained with smaller PEI species, whether branched (25kDa) or linear (22kDa). These vectors were also highly effective in protecting DNA from attack by DNAse I. Transfection activity was maximal by using protocols 3 and 4 and a lipid/DNA molar ratio of 17/1. These complexes showed high efficiency in gene delivery of DNA to liver cancer cells, even in the presence of high concentration of serum (60% FBS). On the other hand, complexes formed with linear PEI (22kDa) were more effective than lipopolyplexes containing branched PEI (800 or 25kDa). The complexes resulted to be much more efficient than conventional lipoplexes (cationic lipid and DNA) and polyplexes (cationic polymer and DNA). The same behaviour was observed for complexes prepared in the presence of the therapeutic gene pCMVIL-12. Toxicity assays revealed a viability higher than 80% in all cases, independently of the protocol, molar ratio (lipid/DNA), molecular weight and type of PEI.     

Implementing and complying with the Smoke-free Hospitals Project in Catalonia, Spain.

The objective of the study was to describe the implementation of measures for preventing tobacco consumption developed in the Catalan Network of Smoke-free Hospitals. Information from 25 hospitals that are actively involved in the Catalan Network of Smoke-free Hospitals (April 2004) was used. The degree of implementation of the Smoke-free Hospitals Project was analysed by means of the Self-Audit Questionnaire of the European Network for Smoke-free Hospitals; each hospital was analysed globally and according to the duration of its Network membership (<1 year: implementation stage; > or =1 year: consolidation stage). In terms of global indicators, there were high levels of commitment (64.8%), communication (74.7%), tobacco control (77.4%) and implementation of smoke-free environments (81.0%). A lower degree of implementation (<50%) was found in education and training, health promotion and healthy workplaces. According to the duration of Network membership, significant differences were observed for communication, environment, healthy workplaces and follow-up. Deficits were observed in areas such as specialist training and cessation support, and further input is required here. By identifying areas needing attention, providing a guide for policy development and by administering it periodically, one can ensure that progress is kept on track.     

Abnormalities of thirst regulation in patients with chronic renal failure on hemodialysis.

To determine whether thirst mechanisms are altered in nondiabetic patients with chronic renal failure on hemodialysis, 4 patients with an average weight gain between dialysis sessions of more than 5% of dry body weight (group I), 5 patients with less than 3% weight gain (group II), and a group of 6 healthy subjects (group III) were submitted to infusion of hypertonic saline. After infusion the subjects had free access to water. Thirst was evaluated by visual analogue rating scales. Despite similar increments of effective plasma osmolality during saline infusion, patients of group I were thirstier than groups II and III (p less than 0.005 and p less than 0.01, respectively). Changes in thirst ratings were similar in groups II and III. Osmotic thresholds for thirst onset were similar in groups II and III (288.9 +/- 8.5 and 289.8 +/- 3.4 mosm/kg, respectively), but lower in group I (277.6 +/- 7.6 mosm/kg). Nevertheless, great variations were observed in the latter group. Thus, 2 patients showed thresholds for thirst within the normal range, whereas the others had low osmolar thresholds for thirst and baseline plasma osmolalities and high basal thirst scores. During the drinking period, the patients of group I drank more (14.2 +/- 2.8 ml/kg) than those of groups II (5.3 +/- 1.6 ml/kg; p less than 0.02) and III (10.2 +/- 1.6 ml/kg; n.s.) The plasma levels of angiotensin II in uremic patients were higher than in healthy subjects, although there were no differences between groups I and II and no correlation between basal angiotensin II levels and the interdialytic weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)