Interfering ribonucleic acids that suppress expression of multiple unrelated genes

<p>Abstract</p> <p>Background</p> <p>Short interfering RNAs (siRNAs) have become the research tool of choice for gene suppression, with human clinical trials ongoing. The emphasis so far in siRNA therapeutics has been the design of one siRNA with complete complementarity to the intended target. However, there is a need for multi-targeting interfering RNA in diseases in which multiple gene products are of importance. We have investigated the possibility of using a single short synthetic duplex RNA to suppress the expression of <it>VEGF-A </it>and <it>ICAM-1</it>; genes implicated in the progression of ocular neovascular diseases such as diabetic retinopathy.</p> <p>Results</p> <p>Duplex RNA were designed to have incomplete complementarity with the 3'UTR sequences of both target genes. One such duplex, CODEMIR-1, was found to suppress VEGF and ICAM-1 by 90 and 60%, respectively in ARPE-19 cells at a transfected concentration of 40 ng/mL. Use of a cyan fusion reporter with target sites constructed in its 3'UTR demonstrated that the repression of VEGF and ICAM-1 by CODEMIR-1 was indeed due to interaction with the target sequence. An exhaustive analysis of sequence variants of CODEMIR-1 demonstrated a clear positive correlation between activity against VEGF (but not ICAM-1) and the length of the contiguous complementary region (from the 5' end of the guide strand). Various strategies, including the use of inosine bases at the sites of divergence of the target sequences were investigated.</p> <p>Conclusion</p> <p>Our work demonstrates the possibility of designing multitargeting dsRNA to suppress more than one disease-altering gene. This warrants further investigation as a possible therapeutic approach.</p

POPcorn: An Online Resource Providing Access to Distributed and Diverse Maize Project Data

The purpose of the online resource presented here, POPcorn (Project Portal for corn), is to enhance accessibility of maize genetic and genomic resources for plant biologists. Currently, many online locations are difficult to find, some are best searched independently, and individual project websites often degrade over time—sometimes disappearing entirely. The POPcorn site makes available (1) a centralized, web-accessible resource to search and browse descriptions of ongoing maize genomics projects, (2) a single, stand-alone tool that uses web Services and minimal data warehousing to search for sequence matches in online resources of diverse offsite projects, and (3) a set of tools that enables researchers to migrate their data to the long-term model organism database for maize genetic and genomic information: MaizeGDB. Examples demonstrating POPcorn's utility are provided herein

In silico modeling indicates the development of HIV-1 resistance to multiple shRNA gene therapy differs to standard antiretroviral therapy

<p>Abstract</p> <p>Background</p> <p>Gene therapy has the potential to counter problems that still hamper standard HIV antiretroviral therapy, such as toxicity, patient adherence and the development of resistance. RNA interference can suppress HIV replication as a gene therapeutic via expressed short hairpin RNAs (shRNAs). It is now clear that multiple shRNAs will likely be required to suppress infection and prevent the emergence of resistant virus.</p> <p>Results</p> <p>We have developed the first biologically relevant stochastic model in which multiple shRNAs are introduced into CD34+ hematopoietic stem cells. This model has been used to track the production of gene-containing CD4+ T cells, the degree of HIV infection, and the development of HIV resistance in lymphoid tissue for 13 years. In this model, we found that at least four active shRNAs were required to suppress HIV infection/replication effectively and prevent the development of resistance. The inhibition of incoming virus was shown to be critical for effective treatment. The low potential for resistance development that we found is largely due to a pool of replicating wild-type HIV that is maintained in non-gene containing CD4+ T cells. This wild-type HIV effectively out-competes emerging viral strains, maintaining the viral <it>status quo</it>.</p> <p>Conclusions</p> <p>The presence of a group of cells that lack the gene therapeutic and is available for infection by wild-type virus appears to mitigate the development of resistance observed with systemic antiretroviral therapy.</p

Pharmacokinetics made easy, revised/ Birkett

xviii, 131 hal.: ill.; 15 cm

Pharmacokinetics made easy, revised/ Birkett

xviii, 131 hal.: ill.; 15 cm

Compliance with restrictions on the subsidized use of proton pump inhibitors in Australia

AimsTo determine among a cohort of patients newly dispensed a prescription for a proton pump inhibitor (PPI) the extent of prior use of other less expensive agents such as antacids and H2-receptor antagonists as evidence of a 'stepped care' approach to peptic ulcer and oesophageal disease.MethodsA retrospective drug utilization study was conducted within the Pharmaceutical Benefits Scheme (PBS) claims database in Australia. A cohort of social security recipients, who received approval for PPI supply in the month of October 1996, had no prior PPI approval in the previous 18 months and went on to have the drug dispensed, was assembled. This group of 'new PPI starters' was then examined for supply of less expensive prescription medicines to treat peptic ulcer and oesophageal disease in the 12 months prior to obtaining their PPI approval.ResultsIn a cohort of 4554 defined new PPI users, 1205 (26.5%) showed no use of H2-receptor antagonists, antacids, cisapride, cytoprotectants or antiregurgitants in the 12 month period prior to commencing the PPI. The major reason for use given by prescribers for PBS supply was 'severe refractory ulcerating oesophagitis'.ConclusionsSubsidized supply is currently restricted on cost-effectiveness grounds to refractory peptic ulcer disease or severe oesophageal disease. Despite this, utilization and epidemiological data suggest that there is widespread leakage of use outside these indications particularly to less severe forms of oesophageal disease. This patient tracking study has shown within the PBS database that around a quarter of the patients are treated directly with a PPI without being prescribed less expensive agents at least in the preceding 12 months.McManus, Peter; Marley, John; Birkett, Donald J.; Lindner, Juli