Search

Objective(s): P-glycoprotein (P-gp) is an efflux protein, the overexpression of which has been associated with multidrug resistance in various cancers. Although siRNA delivery to reverse P-gp expression may be promising for sensitizing of tumor cells to cytotoxic drugs, the therapeutic use of siRNA requires effective carriers that can deliver siRNA intracellularly with minimal toxicity on target cells. We investigated a special class of PEGylated lipid-based nanoparticles (NP), named nanolipoparticles (NLPs), for siRNA- mediated P-gp downregulation. Materials and Methods: NLPs were prepared based on low detergent dialysis method. After characterization, we evaluated the effect of NLPs on siRNA delivery, and P-gp downregulation compared to oligofectamineTM (OFA) in vitro and in vivo. Results: Our results showed a significant decrease in P-gp expression and subsequent enhancement of chemosensitivity to doxorubicin in vitro. Although the effectiveness of NLPs for in vitro siRNA delivery compared to OFA was limited, the results of in vivo studies showed noticeable effectiveness of NLPs for systemic siRNA delivery. siRNA delivery using NLPs could downregulate MDR1 in tumor cells more than 80%, while OFA had a reverse effect on MDR1 expression in vivo. Conclusion: The results indicated that the prepared NLPs could be suitable siRNA delivery systems for tumor therapy.

Background: Brain natriuretic peptide is a predictor of mortality in multiple cardiovascular diseases but its value in patients with chronic kidney disease is still a matter of debate. Patients and methods: We studied 48 haemodialysis patients with mean age 70.0±13.9 years,62.5% female, 43.8% diabetics, with a mean haemodialysis time of 38.1±29.3 months. To evaluate the role of brain natriuretic peptide as a prognostic factor in this population we performed a two-session evaluation of pre- and postmid-week haemodialysis plasma brain natriuretic peptide concentrations and correlated them with hospitalisation and overall and cardiovascular mortality over a two-year period. Results: There were no significant variations in pre– and post-haemodialysis plasma brain natriuretic peptide concentrations. Pre- and post-haemodialysis brain natriuretic peptide concentrations were significantly greater in patients who died from all causes(p=0.034 and p=0.001, respectively) and from cardiovascular causes (p=0.043 and p=0.001, respectively). Patients who were hospitalised in the two-year study period also presented greater pre- and posthaemodialysis brain natriuretic peptide concentrations(p=0.03 and p=0.036, respectively). Patients with mean brain natriuretic peptide concentrations ≥ 390 pg/mL showed a significantly lower survival at the end of the two-year study period. Conclusion: Brain natriuretic peptide was a good predictor of morbidity and mortality (overall and cardiovascular) in our population.

Decreased expression of p16 may result from hypermethylation of the promoter or from deletion of the gene. It can lead to intensified proliferation of neoplastic cells and to cytostatic drug resistance. The study was aimed at the examination of prognostic value of p16 expression in relation to Ki67 and caspase-3 in ovarian cancers using immunohistochemistry. The immunohistochemical studies were performed on 73 paraffinembedded samples of ovarian cancers from 43 patients and samples from 6 healthy ovaries. We have used monoclonal antibodies against p16. ABC method and DAB were used for antigens visualisation. The intensity of the immunohistochemical reactions was appraised using the semi-quantitative IRS scale. In healthy ovaries we have shown strong reaction in the nuclei of surface epithelium. In the case of studied ovarian cancers, the reaction of a nuclear and cytoplasmic localization was obtained. The mean overall immunoreactivity score of nuclear p16 expression amounted to 5.30±3.44 SD in primary laparotomy material and 6.61±4.34 SD in secondary cytoreduction material. Statistical analysis demonstrated that lower p16 expression was typical of the younger patients and the patients who died. Kaplan- Meier’s analysis proved that lower expression of p16 was characteristic of cases with shorter overall survival. In the present study we have demonstrated that lowered p16 expression represented an unfavourable prognostic index in ovarian cancer. Lowered p16 expression was also typical for chemotherapy-resistant ceases (cases of lower caspase-3 and higher Ki67 at secondary cytoreduction expression).

Made available in DSpace on 2015-12-30T10:19:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2005