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991.
992.
Leire García Maria Bu?uales Nejat Düzgüne? Conchita Tros de Ilarduya 《European journal of pharmaceutics and biopharmaceutics》2007,67(1):58-66
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. 相似文献
993.
Carlos Calderón Rafael Rotaeche Arritxu Etxebarria Mercé Marzo Rosa Rico Marta Barandiaran 《BMC health services research》2006,6(1):138-11
Background
The GRADE method represents a new approach to grading the quality of evidence and strength of recommendations in the preparation of Clinical Practice Guidelines (CPG). In the context of a pilot study to assess the implementability of the system in Spain, we considered it relevant to gain an insight into the significance of the perceptions and attitudes expressed by the actual experts participating in the system try-out. 相似文献994.
Paulo Rogério Ferreti Bonan Estela Kaminagakura Fábio Ramoa Pires Pablo Agustin Vargas Oslei Paes de Almeida 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2006,101(2):205-211
OBJECTIVE: The aim of this work was to study cytokeratin (Ck) expression in initial radiation-induced oral mucositis. STUDY DESIGN: Eleven cases of initial radiomucositis of the buccal mucosa and 9 normal specimens were immunostained for Ck 1, 5, 6, 7, 8, 10, 14, 16, 18, and 19 by immunoperoxidase method. RESULTS: Expression of Ck 1, 6, 10, and 16 was stronger in mucositis than in normal mucosa. Ck 7, 8, and 18 were negative for both control and study groups. Ck 5, 13, and 14 were positive for both groups, nevertheless suprabasal staining for Ck 14 was more evident in mucositis than in the control group. Sporadic staining for Ck 19 was observed in 1 case of mucositis and in 2 controls. CONCLUSIONS: Increased Ck expression can be associated with the reactive proliferation of the epithelium and increasing resistance of the oral mucosa during the initial phases of radiotherapy. 相似文献
995.
996.
C Frank S Sagratella M Benedetti A Scotti de Carolis 《Pharmacology, biochemistry, and behavior》1989,33(3):713-715
A transient increase (10 min) in extracellular calcium concentration (4 mM) causes a long-lasting (greater than 2 hr) enhancement of population spike responses evoked by radiatum fibers to CA1 pyramidal neurons in rat hippocampal slices. This phenomenon is similar to tetanic long-term potentiation (LTP), and is also related to memory processes. The influence of various drugs was investigated on calcium-induced LTP. The NMDA antagonist 2 amino-5-phosphonopentanoic acid (AP5; 100 microM) was able to prevent the calcium-induced LTP, while atropine sulphate (10 microM), propranolol hydrochloride (10 microM) and verapamil hydrochloride (100 microM) were ineffective. The results suggest an involvement of the NMDA receptor in the development of calcium-induced LTP. 相似文献
997.
998.
999.
W L de Kort M A Verschoor A A Wibowo J J van Hemmen 《American journal of industrial medicine》1987,11(2):145-156
A group of workers, occupationally exposed to lead and cadmium compounds (n = 53), was compared to a group of workers not exposed to these metals (n = 52). The average values of systolic, diastolic, and mean blood pressure were found to be higher in the exposed group (p less than 0.05). In contrast with the correlation between CdU and blood pressure, the correlation between PbB and systolic and mean blood pressure remained statistically significant after controlling for age and pulse rate (r = 0.22, p less than 0.05). The prevalence of potential hypertension (defined as systolic blood pressure greater than or equal to 160 mm Hg and/or diastolic blood pressure greater than or equal to 95 mm Hg and/or under treatment for hypertension) was higher in the exposed group, but the observed relative risk was not statistically significant: relative risk = 1.91 (95% confidence limits, 0.90-4.05). Furthermore, a significant correlation between PbB and Hgb (r = -0.28, p = 0.004) was observed. Differences in kidney function, as assessed in this study, were not detected. 相似文献
1000.