86 research outputs found
Perceived effects of participation in the financial planning and budgeting processes on selected Michigan community colleges
Thesis (Ph. D.)--Michigan State University. Department of Educational Administration, 1988Includes bibliographical references (pages 201-206
The identification of a novel role for BRCA1 in regulating RNA Polymerase I transcription
The unrestrained proliferation of cancer cells requires a high level of ribosome biogenesis. The first stage of ribosome biogenesis is the transcription of the large ribosomal RNAs (rRNAs); the structural and functional components of the ribosome. Transcription of rRNA is carried out by RNA polymerase I (Pol-I) and its associated holoenzyme complex.
Here we report that BRCA1, a nuclear phosphoprotein, and a known tumour suppressor involved in variety of cellular processes such as DNA damage response, transcriptional regulation, cell cycle control and ubiquitylation, is associated with rDNA repeats, in particular with the regulatory regions of the rRNA gene.
We demonstrate that BRCA1 interacts directly with the basal Pol-I transcription factors; upstream binding factor (UBF), selectivity factor-1 (SL1) as well as interacting with RNA Pol-I itself. We show that in response to DNA damage, BRCA1 occupancy at the rDNA repeat is decreased and the observed BRCA1 interactions with the Pol-I transcription machinery are weakened.
We propose, therefore, that there is a rDNA associated fraction of BRCA1 involved in DNA damage dependent regulation of Pol-I transcription, regulating the stability and formation of the Pol-I holoenzyme during initiation and/or elongation in response to DNA damage
Monotherapie der Parkinsonschen Erkrankung mit Budipin - Ein randomisierter Doppelblindvergleich mit Amantadin -
Breast cancer resistance protein (ABCG2) in clinical pharmacokinetics and drug interactions: practical recommendations for clinical victim and perpetrator drug-drug interaction study design
Breast cancer resistance protein (BCRP; ABCG2) limits intestinal absorption of low-permeability substrate drugs and mediates biliary excretion of drugs and metabolites. Based on clinical evidence of BCRP-mediated drug-drug interactions (DDIs) and the c.421C>A functional polymorphism affecting drug efficacy and safety, both the US Food and Drug Administration and European Medicines Agency recommend preclinical evaluation and, when appropriate, clinical assessment of BCRP-mediated DDIs. Although many BCRP substrates and inhibitors have been identified in vitro, clinical translation has been confounded by overlap with other transporters and metabolic enzymes. Regulatory recommendations for BCRP-mediated clinical DDI studies are challenging, as consensus is lacking on the choice of the most robust and specific human BCRP substrates and inhibitors and optimal study design. This review proposes a path forward based on a comprehensive analysis of available data. Oral sulfasalazine (1000 mg, immediate-release tablet) is the best available clinical substrate for intestinal BCRP, oral rosuvastatin (20 mg) for both intestinal and hepatic BCRP, and intravenous rosuvastatin (4 mg) for hepatic BCRP. Oral curcumin (2000 mg) and lapatinib (250 mg) are the best available clinical BCRP inhibitors. To interrogate the worst-case clinical BCRP DDI scenario, study subjects harboring the BCRP c.421C/C reference genotype are recommended. In addition, if sulfasalazine is selected as the substrate, subjects having the rapid acetylator phenotype are recommended. In the case of rosuvastatin, subjects with the organic anion-transporting polypeptide 1B1 c.521T/T genotype are recommended, together with monitoring of rosuvastatin's cholesterol-lowering effect at baseline and DDI phase. A proof-of-concept clinical study is being planned by a collaborative consortium to evaluate the proposed BCRP DDI study design
Breast Cancer Resistance Protein (ABCG2) in Clinical Pharmacokinetics and Drug Interactions: Practical Recommendations for Clinical Victim and Perpetrator Drug-Drug Interaction Study Design
Disposition and Metabolism of Ralfinamide, a Novel Na-Channel Blocker, in Healthy Male Volunteers
Ralfinamide is an α-aminoamide derivative with ion channel blocking properties, acting both peripherally and centrally through different molecular targets important in pain control. Absorption, blood and plasma time courses, and urinary and faecal excretion of total radioactivity were assessed in 6 male healthy volunteers administered a single oral dose of 320 mg <sup>14</sup>C-(S)-ralfinamide. Pharmacokinetics of the parent drug were investigated over 120 h, urinary and plasma metabolites up to 192 h post-dose. <sup>14</sup>C-(S)-ralfinamide was rapidly and completely absorbed. Ralfinamide and the dealkylated ralfinamide metabolite (NW-1716) represented the majority of plasma radioactivity. Plasma elimination of the parent compound occurred mono-exponentially (half-life approx. 15 h). <sup>14</sup>C-radioactivity was eliminated in a bi-phasic manner (terminal half-life of 60 and 24 h for plasma and whole blood, respectively). Plasma-concentrations of unchanged ralfinamide were significantly lower than radioactivity concentrations, indicating metabolism of the parent compound. At 192 h post-dose the total balance of radioactivity was almost complete (95%). The main route of excretion was via the kidneys (94% of the dose). Major metabolites identified in urine and plasma were the N-dealkylated acid of ralfinamide and deaminated ralfinamide acid (NW-1799). Other metabolites, in particular the product of glucuronide conjugation N-dealkylated-β-glucuronide, were identified.</jats:p
Direct HPLC separation of enantiomers of pantoprazole and other benzimidazole sulfoxides using cellulose-based chiral stationary phases in reversed-phase mode
A method for detecting and preventing negative RNA interference in preparation of lentiviral vectors for siRNA delivery
The lentiviral vector is a useful tool for delivery of hairpin siRNA (shRNA) into mammalian cells. However, the efficiency of this system for carrying double-stranded siRNA (dsRNA) has not been explored. In this study we cloned the two forms of siRNA-coding sequence, a palindromic DNA with a spacer loop for shRNA and a double-stranded DNA with opposing Pol III promoters for dsRNA, into lentiviral DNA vectors, and compared their viral vector production yields. Our results indicate that sharply lower titer vector was obtained for dsRNA while much higher titer vector was produced for shRNA, posing a fundamental concern whether siRNA-carrying viral RNA itself is an inherent target of RNAi. Further experimental analyses using packaging cells that either allow or do not allow siRNA transcription indicate that the shRNA-carrying viral RNA is resistant to RNAi but the viral RNA carrier for dsRNA is not, offering a linker of RNAi bias–target secondary structure that causes shRNA vector to evade RNAi degradation. More importantly, the poor yield of dsRNA vector production was restored when a novel packaging cell line was used that blocks the antisense strand from dsRNA duplexes. This method has important implications for the RNAi field, especially for those who are using lentiviral dsRNA and dsRNA libraries for various biological discovery and therapeutic interventions
- …
