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The effect of combretastatin A4 disodium phosphate and 5,6-dimethylxanthenone-4-acetic acid on water diffusion and blood perfusion in tumours.
2008-01-01
PURPOSE: To evaluate the effect of the vascular disrupting drugs combretastatin A-4 disodium phosphate (CA4DP) and 5,6-dimethylxanthenone-4-acetic acid (DMXAA) on the intra/extracellular volume fraction of water and blood perfusion in tumours using MRI. METHODS AND MATERIALS: Mice with C3H mammary carcinomas underwent repeated MRI T2-weighted imaging, water-diffusion and perfusion measurements before and up to 6-hours following CA4DP and DMXAA treatment. RESULTS: CA4DP treatment caused an increase in water diffusion in those tumour areas that presented the lowest blood perfusion, however this appeared only after five hours. The blood perfusion in highly perfused tumour regions decreased immediately after administration of CA4DP. DMXAA treatment caused an early decrease in water diffusion in the low-perfused tumour segments and followed by a subsequent decrease in the remaining part of the tumour. The blood perfusion decreased early in all parts of the tumour. CONCLUSION: The effect of CA4DP and DMXAA on tumour blood flow was comparable. The reduction in regional blood flow caused by CA4DP in the whole tumour segment occurred early, however, changes in ADC after DMXAA appeared more extended and earlier than after CA4DP treatment, especially in tumour areas already suffering from a low blood perfusion.
2008-01-01
Purpose. To evaluate the effect of the vascular disrupting drugs combretastatin A-4 disodium phosphate (CA4DP) and 5,6-dimethylxanthenone-4-acetic acid (DMXAA) on the intra/extracellular volume fraction of water and blood perfusion in tumours using MRI. Methods and materials. Mice with C3H mammary carcinomas underwent repeated MRI T2-weighted imaging, water-diffusion and perfusion measurements before and up to 6-hours following CA4DP and DMXAA treatment. Results. CA4DP treatment caused an increase in water diffusion in those tumour areas that presented the lowest blood perfusion, however this appeared only after five hours. The blood perfusion in highly perfused tumour regions decreased immediately after administration of CA4DP. DMXAA treatment caused an early decrease in water diffusion i...
Early effects of combretastatin-A4 disodium phosphate on tumor perfusion and interstitial fluid pressure
2007-01-01
Combretastatin-A4 disodium phosphate (CA4DP) is a vascular-disruptive agent that causes an abrupt decrease in tumor blood flow. The direct actions of CA4DP include increases in vascular permeability and destabilization of the endothelial cytoskeleton, which are thought to contribute to occlusion of the tumor vasculature. It has been proposed that increased permeability causes a transient increase in interstitial fluid pressure (IFP), which in turn could collapse intratumoral blood vessels. We examined the immediate effects of CA4DP on tumor IFP in C3H mammary carcinoma. Mice were treated with 100 mg/kg CA4DP by intraperitoneal injection. Tumor perfusion was recorded by laser Doppler flowmetry at separate time points, and IFP was recorded continuously by the wick-in-needle method. In this study, we found that CA4DP treatment resulted in a rapid reduction in tumor perfusion, followed by a decrease in IFP; no increases in IFP were observed. This suggests that CA4DP-induced reductions in tumor perfusion are not dependent on increases in IFP
1993-12-01
The purpose of the summer undergraduate internship program for research in environmental studies is to provide an opportunity for well-qualified students to undertake an original research project as an apprentice to an active research scientist in basic environmental research. Ten students from throughout the midwestern and eastern areas of the country were accepted into the program. These students selected projects in the areas of marine sciences, biostatistics and epidemiology, and toxicology. The research experience for all these students and their mentors was very positive. The seminars were well attended and the students showed their interest in the presentations and environmental sciences as a whole by presenting the speakers with thoughtful and intuitive questions. This report contains the research project written presentations prepared by the student interns.
2008-12-01
Neutrophil granulocytes play an important role in innate host defence against microbial invasions and they are also the key effector cells in mediating host tissue damage. These functions often rely...Full Text Available
2008-12-01
Full Text Available.Neutrophil granulocytes play an important role in innate host defence against microbial invasions and they are also the key effector cells in mediating host tissue damage. These functions often rely on the production of reactive oxygen species (ROS) from the membrane-bound NADPH-oxidase system. The magnitude of ROS production varies depending on the state of the cells, i.e. resting or primed. Many priming agents as well as potent NADPH-oxidase activators have been identified and characterized for human neutrophils. The cytokine tumour necrosis factor (TNF)-α is one prominent example of a priming agent and the synthetic hexapeptide WKYMVm is an agonist that triggers an activation of the NADPH-oxidase of human neutrophils through two members of the formyl peptide family of receptors, formyl peptide receptor (FPR) and FPR-like 1 (FPRL1). This peptide also activates murine neutrophils but the precise receptor involved has not been previously characterized. We show in this study that WKYMVm activates stably transfected HL60 cells expressing murine formyl peptide receptor-related sequence 2 (Fpr-rs2) and that activation of murine neutrophils with WKYMVm is blocked by an FPRL1-specific antagonist. WKYMVm is thus an agonist for Fpr-rs2 and we suggest that this receptor is in fact the mouse orthologue of FPRL1. In addition, we show that the WKYMVm response in murine neutrophils can be primed by TNF-α and this priming process involves mobilization of subcellular granules. The results obtained using neutrophils derived from TNF receptor type I (TNFRI)-deficient animals suggest that TNF-α exerts its priming effect via the TNFRI.
The procedures manual of the Environmental Measurements Laboratory. Volume 2, 28. edition
1997-02-01
This report contains environmental sampling and analytical chemistry procedures that are performed by the Environmental Measurements Laboratory. The purpose of environmental sampling and analysis is to obtain data that describe a particular site at a specific point in time from which an evaluation can be made as a basis for possible action.
The element technology of clean fuel alcohol plant construction
1996-02-01
The fuel alcohol has been highlighted as a clean energy among new renewable energy sources. However, the production of the fuel alcohol has following problems; (i)bulk distillate remains is generated and (ii) benzene to be used as a entertainer in the azeotropic distillation causes the environmental problem. Thus, we started this research on the ground of preserving the cleanness in the production of fuel alcohol, a clean energy. We examined the schemes of replacing the azotropic distillation column which causes the problems with MSDP(Molecular Sieve Dehydration Process) system using adsorption technology and of treating the bulk distillate remains to be generated as by-products. In addition, we need to develop the continuous yea station technology for the continuous operation of fuel alcohol plant as a side goal. Thus, we try to develop a continuous ethanol fermentation process by high-density cell culture from tapioca, a industrial substrate, using cohesive yeast. For this purpose, we intend to examine the problem of tapioca, a industrial substrate, where a solid is existed and develop a new process which can solve the problem. Ultimately, the object of this project is to develop each element technology for the construction of fuel alcohol plant and obtain the ability to design the whole plant. (author) 54 refs., 143 figs., 34 tabs.
Tank characterization data report: Tank 241-C-112
1993-04-01
Tank 241-C-112 is a Hanford Site Ferrocyanide Watch List tank that was most recently sampled in March 1992. Analyses of materials obtained from tank 241-C-112 were conducted to support the resolution of the Ferrocyanide Unreviewed Safety Question (USQ) and to support Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-10-00. Analysis of core samples obtained from tank 241-C-112 strongly indicates that the fuel concentration in the tank waste will not support a propagating exothermic reaction. It is probable that tank 241-C-112 exceeds the 1,000 g-mol inventory criteria established for the Ferrocyanide USQ; however, extensive energetic analysis of the waste has determined a maximum exothermic value of -9 cal/g dry waste. This value is substantially below any levels of concern (-75 cal/g). In addition, an investigation of potential mechanisms to generate concentration levels of radionuclides high enough to be of concern was performed. No credible mechanism was postulated that could initiate the formation of such concentration levels in the tank. Tank 241-C-112 waste is a complex material made up primarily of water and inert salts. The insoluble solids are a mixture of phosphates, sulfates, and hydroxides in combination with aluminum, calcium, iron, nickel, and uranium. Disodium nickel ferrocyanide and sodium cesium nickel ferrocyanide probably exist in the tank; however, there appears to have been significant degradation of this material since the waste was initially settled in the tank.
System 80+{trademark} Standard Design: CESSAR design certification. Volume 17: Amendment I
1990-12-21
This report, entitled Combustion Engineering Standard Safety Analysis Report -- Design Certification (CESSAR-DC), has been prepared in support of the industry effort to standardize nuclear plant designs. These volumes describes the Combustion Engineering, Inc. System 80+{trademark} Standard Design. This Volume 17 provides Appendix A of this report, closure of unresolved and Genetic Safety Issues.
2008-01-01
The porphyrazines (pzs), a class of porphyrin analogues, are being investigated for their potential use as tumor imaging/therapeutic agents. We here examine six peripherally-functionalized M[pz(Full Text Available
2008-01-01
Full Text Available.The porphyrazines (pzs), a class of porphyrin analogues, are being investigated for their potential use as tumor imaging/therapeutic agents. We here examine six peripherally-functionalized M[pz(AnB4-n)] pzs with n=4, 3, or 2 (in a trans conformation) and M = H2 or Zn, where A is an [S((CH2)2O)4Me]2 unit and B is a fused β,β′-diisopropyloxybenzo group. Cell viability/proliferation assays and fluorescence microscopy were carried out in both tumor and normal cells. Dark toxicity studies disclosed that four of the compounds exhibited toxicity in both normal and tumor cells; one was nontoxic in both normal and tumor cells, and one was selectively toxic to normal cells. Additionally, three of the pzs showed enhanced photo-induced toxicity with these effects in some cases being observed at treatment concentrations of up to ten-fold lower than that needed for a response in Photofrin. All six compounds were preferentially absorbed by tumor cells, suggesting that they have potential as in vitro diagnostic agents and as aids in the isolation and purification of aberrant cells from pathological specimens. In particular, two promising diagnostic candidates have been identified as part of this work.
2009-01-01
The purpose of the present study was to use capacitive coupling of pulsed electromagnetic field (CC-PEMF) and hydroxyapatite nanoparticles (HAp) as a countermeasure to prevent osteoporosis induced by...Full Text Available
2009-01-01
Full Text Available.The purpose of the present study was to use capacitive coupling of pulsed electromagnetic field (CC-PEMF) and hydroxyapatite nanoparticles (HAp) as a countermeasure to prevent osteoporosis induced by simulated microgravity. We used the hind-limb suspension (HLS) rat model to simulate microgravity-induced bone losses for 45 days. In order to compare the resulting changes, mineralogical (bone mineral density [BMD], calcium [Ca], and phosphorus [P]), biochemical (osteocalcin, alkaline phosphatase [ALP], and type I collagen), and histological (scanning electron microscopy) parameters were adopted. As a countermeasure to the above, the effect of PEMF and HAp application were examined. Three-month-old female Wistar rats were randomly divided into control (n = 8), HLS (n = 8), HLS with PEMF (n = 8), HLS with HAp nanoparticles (n = 8), and HLS with HAp and PEMF (n = 8). We observed: 1) significant decrease (p < 0.01) in BMD, Ca, P, type I collagen, and ALP activity in femur and tibia in hind-limb bone and serum osteocalcin in HLS rats as compared with the ground control. 2) Nonsignificant increase in BMD (p < 0.1), Ca (p < 0.1), P (p < 0.5), type I collagen (p < 0.1), and ALP activity (p < 0.5) in femur and tibia in hind-limb bone and serum osteocalcin (p < 0.5) in HLS + PEMF rats compared with HLS rats. 3) Significant increase in BMD (p < 0.02), Ca (p < 0.05), P (p < 0.05), type I collagen (p < 0.02), and ALP activity (p > 0.02) in femur and tibia in hind-limb bone with a nonsignificant increase in serum osteocalcin (p > 0.1) in HLS + HAp rats compared to HLS rats. 4) Significant increase in BMD (p > 0.01). Ca (p > 0.01). P (p > 0.01). type I collagen (p > 0.01). and ALP activity (p > 0.01) in femur and tibia in hind-limb bone and serum osteocalcin (p > 0.02) were also observed. Results suggest that a combination of low level PEMF and Hap nanoparticles has potential to control bone loss induced by simulated microgravity.
Survey of Water Chemistry and Corrosion of NPP
2008-06-15
Status of water chemistry of nuclear power plant and materials corrosion has been surveyed. For PWR, system chemistry of primary coolant and secondary coolant as well as the related corrosion of materials was surveyed. For BWR, system chemistry as whole has been surveyed with its accompanying corrosion problems. Radiolysis of coolant water and activation of corrosion products also was surveyed. Future NPP such as supercritical water cooled reactor and fusion reactor has also been surveyed for their water chemistry and corrosion problems. As a result, proposal for some research items has been suggested. Some related corrosion research techniques and electrochemical fundamentals are also presented.
2008-03-01
Sixty-two clinical isolates of Enterobacter aerogenes resistant to expanded-spectrum cephalosporins were collected between July 2003 and May 2005. Among these isolates, 23 (37.1%)...Full Text Available
2008-03-01
Full Text Available.Sixty-two clinical isolates of Enterobacter aerogenes resistant to expanded-spectrum cephalosporins were collected between July 2003 and May 2005. Among these isolates, 23 (37.1%) were imipenem (IPM) susceptible, and 39 (62.9%) were IPM insusceptible, of which 89.7% (35/39) were resistant and 10.3% (4/39) were intermediate. Isolate genotypes were compared by pulsed-field gel electrophoresis. Of 62 isolates, 48 belonged to epidemic pulsotype A (77.4%). This pulsotype included 37.5% and 58.4% of β-lactam phenotypes b and a, respectively. Nine isolates (14.5%) belonged to pulsotype E, which included 22.3% and 77.7% of phenotypes b and a, respectively. The β-lactamases with pIs of 5.4, 6.5, 8.2, and 8.2 corresponded to extended-spectrum β-lactamases (ESBLs) TEM-20, TEM-24, SHV-5, and SHV-12, respectively. Of 39 IPM-insusceptible E. aerogenes isolates, 26 (66.6%) were determined to be metallo-β-lactamase producers, by using a phenotypic method. Of these isolates, 24 harbored a blaIMP-1 gene encoding a protein with a pI of >9.5, and two carried the blaVIM-2 gene encoding a protein with a pI of 5.3, corresponding to β-lactamases IMP-1 and VIM-2, respectively. The remaining 13 (33.4%) isolates were negative for the blaIMP-1 and blaVIM-2 genes but showed an alteration of their outer membrane proteins (OMPs). Ten of these isolates produced the two possible OMPs (32 and 42 kDa), with IPM MICs between 8 and 32 μg/ml, and three others produced only a 32-kDa OMP with IPM MICs >32 μg/ml. This work demonstrates that, in addition to resistance to expanded-spectrum cephalosporins, IPM resistance can occur in ESBL-producing E. aerogenes isolates by carbapenemase production or by the loss of porin in the outer membrane.
Structure-guided engineering of the regioselectivity of RNA ligase ribozymes
2009-03-18
Ribozyme-catalyzed RNA synthesis is central to the RNA world hypothesis. No natural RNA polymerase ribozymes have been discovered. However, ribozymes that catalyze the requisite chemistry, generating...Full Text Available
Structure-guided engineering of the regioselectivity of RNA ligase ribozymes
2009-03-18
Full Text Available.Ribozyme-catalyzed RNA synthesis is central to the RNA world hypothesis. No natural RNA polymerase ribozymes have been discovered. However, ribozymes that catalyze the requisite chemistry, generating a new phosphodiester through attack of a terminal hydroxyl of an RNA on the α-phosphate of a triphosphate-activated oligonucleotide, have been isolated by in vitro selection. These experiments often yield ribozymes that generate 2'–5' phosphodiesters rather than conventional 3'–5' linkages. We have determined crystal structures of the duplex formed by the template segment of a representative 2'–5' RNA ligase ribozyme, the class II ligase, and its ligation product. The structures reveal a product-template duplex with a G•A pair at the ligation junction. This sheared pair is flanked on one side by a minor groove-broadening wedge comprised of two unpaired nucleotides. The reported structure of an independently isolated 3'–5' ligase ribozyme, the L1 ligase, shows a product-template duplex that shares the G•A pair with the class II ligase. However, this G•A pair is flanked by G•U wobbles, rather than an unpaired wedge. We demonstrate that these structural differences of the substrate-template duplexes are largely responsible for the divergent regioselectivity of the two ribozymes, independent of their catalytic moieties, by constructing chimeras. The L1 ligase with a class II substrate-template duplex shows a thirty-fold increase in 2'–5' bond synthesis, while the class II ligase with an L1 substrate-template duplex produces 3'–5' bonds exclusively. These results demonstrate how local geometry inherent to the substrate-template duplexes controls the regioselectivity of ribozyme-catalyzed RNA ligaiton reactions.
Sample processing for DNA chip array-based analysis of enterohemorrhagic Escherichia coli (EHEC)
Full Text Available.BackgroundExploitation of DNA-based analyses of microbial pathogens, and especially simultaneous typing of several virulence-related genes in bacteria is becoming an important objective of public health these days.ResultsA procedure for sample processing for a confirmative analysis of enterohemorrhagic Escherichia coli (EHEC) on a single colony with DNA chip array was developed and is reported here. The protocol includes application of fragmented genomic DNA from ultrasonicated colonies. The sample processing comprises first 2.5 min of ultrasonic treatment, DNA extraction (2×), and afterwards additional 5 min ultrasonication. Thus, the total sample preparation time for a confirmative analysis of EHEC is nearly 10 min. Additionally, bioinformatic revisions were performed in order to design PCR primers and array probes specific to most conservative regions of the EHEC-associated genes. Six strains with distinct pathogenic properties were selected for this study. At last, the EHEC chip array for a parallel and simultaneous detection of genes etpC-stx1-stx2-eae was designed and examined. This should permit to sense all currently accessible variants of the selected sequences in EHEC types and subtypes.ConclusionIn order to implement the DNA chip array-based analysis for direct EHEC detection the sample processing was established in course of this work. However, this sample preparation mode may also be applied to other types of EHEC DNA-based sensing systems.
Sample processing for DNA chip array-based analysis of enterohemorrhagic Escherichia coli (EHEC)
BackgroundExploitation of DNA-based analyses of microbial pathogens, and especially simultaneous typing of several virulence-related genes in bacteria is becoming an important objective...Full Text Available
1993-03-01
This is the seventh quarterly report on the progress of activities addressing safety issues associated with Hanford Site high-level radioactive waste tanks that contain ferrocyanide compounds. In the presence of oxidizing materials, such as nitrates or nitrites, ferrocyanide can be made to explode in the laboratory by heating it to high temperatures [above 285{degrees}C (545{degrees}F)]. In the mid 1950s approximately 140 metric tons of ferrocyanide were added to 24 underground high-level radioactive waste tanks. An implementation plan (Cash 1991) responding to the Defense Nuclear Facilities Safety Board Recommendation 90-7 (FR 1990) was issued in March 1991 describing the activities that were planned and underway to address each of the six parts of Recommendation 90-7. A revision to the original plan was transmitted to US Department of Energy by Westinghouse Hanford Company in December 1992. Milestones completed this quarter are described in this report. Contents of this report include: Introduction; Defense Nuclear Facilities Safety Board Implementation Plan Task Activities (Defense Nuclear Facilities Safety Board Recommendation for enhanced temperature measurement, Recommendation for continuous temperature monitoring, Recommendation for cover gas monitoring, Recommendation for ferrocyanide waste characterization, Recommendation for chemical reaction studies, and Recommendation for emergency response planning); Schedules; and References. All actions recommended by the Defense Nuclear Facilities Safety Board for emergency planning by Hanford Site emergency preparedness organizations have been completed.
Organic tanks safety program, FY97 waste aging studies. Revision 1
1998-02-01
To model tank waste aging and interpret tank waste speciation results, the authors began measuring the reactivity of organic complexants and related compounds towards radiation-induced oxidation reactions. Because of the high efficiency of scavenging of the primary radicals of water radiolysis by nitrate and nitrite ion, the major radiolytically-generated radicals in these solutions, and in Hanford tank wastes, are NO{sub 2}, NO and O{sup {minus}}. Prior to this effort, little quantitative information existed for the reactions of these radicals with organic compounds such as those that were used in Hanford processes. Therefore, modeling of actual waste aging, or even simulated waste aging, was not feasible without measuring reactivities and determining reaction paths. The authors have made the first rate measurements of complexant aging and determined some of their degradation products.
National Synchrotron Light Source Activity Report 1998
1999-05-01
National Synchrotron Light Source Activity Report for period October 1, 1997 through September 30, 1998
Minutes of the Tank Waste Science Panel meeting January 12--13, 1993
1993-10-01
The eight meeting of the Tank Waste Science Panel (Science Panel) was convened January 12, 1993 in Richland, Washington. A list of attendees at this meeting is provided in Appendix A. Appendix B is the agenda prepared for the meeting. It was not strictly followed. The meeting focused on the presentation and discussion of recent information and results obtained from studies conducted to understand flammable gas released and ferrocyanide content behavior in Hanford waste tanks. The Science Panel discussed work performed at Pacific Northwest Laboratoy PNL, Westinghouse Hanford Company, Florida State University, and Fauske Associates. A number of recommendations and observations were made.
Microtubule Dynamics as a Target in Oncology
2009-05-01
Full Text Available.Drugs that affect microtubule dynamics, including the taxanes and vinca alkaloids, have been a mainstay in the treatment of leukemias and solid tumors for decades. New, more effective microtubule-targeting agents continue to enter into clinical trials and some, including the epothilone ixapebilone, have been approved for use. In contrast, several other drugs of this class with promising preclinical data were later shown to be ineffective or intolerable in animal models or clinical trials. In this review we discuss the molecular mechanisms as well as preclinical and clinical results for a variety of microtubule-targeting agents in various stages of development. We also offer a frank discussion of which microtubule-targeting agents are amenable to further development based on their availability, efficacy and toxic profile.
Microtubule Dynamics as a Target in Oncology
2009-05-01
Drugs that affect microtubule dynamics, including the taxanes and vinca alkaloids, have been a mainstay in the treatment of leukemias and solid tumors for decades. New, more effective microtubule-targeting...Full Text Available
Mechanism of Mg2+ Binding in the Na+,K+-ATPase
2009-05-06
Full Text Available.AbstractThe Mg2+ dependence of the kinetics of the phosphorylation and conformational changes of Na+,K+-ATPase was investigated via the stopped-flow technique using the fluorescent label RH421. The enzyme was preequilibrated in buffer containing 130 mM NaCl to stabilize the E1(Na+)3 state. On mixing with ATP, a fluorescence increase was observed. Two exponential functions were necessary to fit the data. Both phases displayed an increase in their observed rate constants with increasing Mg2+ to saturating values of 195 (± 6) s−1 and 54 (± 8) s−1 for the fast and slow phases, respectively. The fast phase was attributed to enzyme conversion into the E2MgP state. The slow phase was attributed to relaxation of the dephosphorylation/rephosphorylation (by ATP) equilibrium and the buildup of some enzyme in the E2Mg state. Taking into account competition from free ATP, the dissociation constant (Kd) of Mg2+ interaction with the E1ATP(Na+)3 state was estimated as 0.069 (± 0.010) mM. This is virtually identical to the estimated value of the Kd of Mg2+-ATP interaction in solution. Within the enzyme-ATP-Mg2+ complex, the actual Kd for Mg2+ binding can be attributed primarily to complexation by ATP itself, with no apparent contribution from coordination by residues of the enzyme environment in the E1 conformation.
Mechanism of Mg2+ Binding in the Na+,K+-ATPase
2009-05-06
AbstractThe Mg2+ dependence of the kinetics of the phosphorylation and conformational changes of Na+,K+-ATPase was investigated...Full Text Available
Manual of analytical methods for the Industrial Hygiene Chemistry Laboratory
1991-08-01
This Manual is compiled from techniques used in the Industrial Hygiene Chemistry Laboratory of Sandia National Laboratories in Albuquerque, New Mexico. The procedures are similar to those used in other laboratories devoted to industrial hygiene practices. Some of the methods are standard; some, modified to suit our needs; and still others, developed at Sandia. The authors have attempted to present all methods in a simple and concise manner but in sufficient detail to make them readily usable. It is not to be inferred that these methods are universal for any type of sample, but they have been found very reliable for the types of samples mentioned.
Implementation plan for the Defense Nuclear Facilities Safety Board Recommendation 90-7. Revision 1
1992-12-01
This document revises the original plan submitted in March 1991 for implementing the recommendations made by the Defense Nuclear Facilities Safety Board in their Recommendation 90-7 to the US Department of Energy. Recommendation 90-7 addresses safety issues of concern for 24 single-shell, high-level radioactive waste tanks containing ferrocyanide compounds at the Hanford Site. The waste in these tanks is a potential safety concern because, under certain conditions involving elevated temperatures and low concentrations of nonparticipating diluents, ferrocyanide compounds in the presence of oxidizing materials can undergo a runaway (propagating) chemical reaction. This document describes those activities underway by the Hanford Site contractor responsible for waste tank safety that address each of the six parts of Defense Nuclear Facilities Safety Board Recommendation 90-7. This document also identifies the progress made on these activities since the beginning of the ferrocyanide safety program in September 1990. Revised schedules for planned activities are also included.
Hanford environmental analytical methods: Methods as of March 1990. Volume 3, Appendix A2-I
1993-05-01
This paper from the analytical laboratories at Hanford describes the method used to measure pH of single-shell tank core samples. Sludge or solid samples are mixed with deionized water. The pH electrode used combines both a sensor and reference electrode in one unit. The meter amplifies the input signal from the electrode and displays the pH visually.
2008-05-01
Full Text Available.A central composite design was employed to produce microcapsules of propranolol hydrochloride by o/o emulsion solvent evaporation technique using a mixture of cellulose acetate butyrate as coat material and span-80 as an emulsifier. The effect of formulation variables namely levels of cellulose acetate butyrate (X1) and percentage of Span-80 (X2) on encapsulation efficiency (Y1), drug release at the end of 1.5 h (Y2), 4 h (Y3), 8 h (Y4), 14 h (Y5), and 24 h (Y6) were evaluated using the F test. Mathematical models containing only the significant terms were generated for each response parameter using multiple linear regression analysis and analysis of variance. Both the formulation variables exerted a significant influence (P <0.05) on Y1 whereas the cellulose acetate butyrate level emerged as the lone factor which significantly influenced the other response parameters. Numerical optimization using desirability approach was employed to develop an optimized formulation by setting constraints on the dependent and independent variables. The experimental values of Y1, Y2, Y3, Y4, Y5, and Y6 for the optimized formulation was found to be 92.86±1.56% w/w, 29.58±1.22%, 48.56±2.56%, 60.85±2.35%, 76.23±3.16% and 95.12±2.41%, respectively which were in close agreement with those predicted by the mathematical models. The drug release from microcapsules followed first order kinetics and was characterized by Higuchi diffusion model. The optimized microcapsule formulation developed was found to comply with the USP drug release test-1 for extended release propranolol hydrochloride capsules.
2008-05-01
A central composite design was employed to produce microcapsules of propranolol hydrochloride by o/o emulsion solvent evaporation technique using a mixture of cellulose acetate butyrate as coat material...Full Text Available
Ferrocyanide Safety Project: FY 1991 annual report
1992-06-01
The Hanford Ferrocyanide Task Team is addressing issues involving ferrocyanide precipitates in the single-shell waste storage tanks (SSTs), in particular the risk of explosion. This Task Team, which is composed of researchers from Westinghouse Hanford Company (WHC), Pacific Northwest Laboratory (PNL), an outside consultants, was formed in response to the need for an updated analysis of safety questions on the Hanford SSTSs. The Ferrocyanide Safety Project, discussed in this report, is being conducted by PNL as part of the Waste Tank Safety Program led by WHC. The overall purpose of the WHC program, which is sponsored by the US Department of Energy's Tank Safety Project Office, is to provide technical information on ferrocyanide chemistry and its interaction and reactive behavior with other tank constituents. Ultimately, this information will be used to maintain the tanks in a safe condition, implement interim stabilization strategies, and identify optimal disposal options. While by itself ferrocyanide is a stable complex of ferrous ion and cyanide, it can be made to explode in the laboratory in the presence of oxidizing materials such as nitrates and/or nitrites temperatures above 280{degree}C or by sufficient electrical spark. The specific goal of the PNL project is so determine the conditions necessary for the ferrocyanide-bearing wastes in Hanford SSTs to represent a hazard, to determine the conditions where these same wastes am not a hazard, or to determine the conditions which are necessary to assure the wastes are safe prior to treatment for permanent disposal. This annual report gives the results of the work conducted by PNL in FY 1991. The activities mainly focused on preparing and characterizing synthetic wastes and alkali nickel ferrocyanides produced using the In-Farm cesium scavenging flowsheet and pure potential nickel ferrocyanides that could be produced by all of the cesium scavenging flowsheets.
Ferrocyanide Safety Program: Data interpretation report for tank 241-T-107 core samples
1994-08-01
Between November 1992 and March 1993, three core samples were obtained from tank 241-T-107. Analyses were performed on these core samples to support the Ferrocyanide Safety Program and the Hanford Federal Facility Agreement and Consent Order (Ecology et al. 1994) Milestone M-10-00. This document summarizes and evaluates those analytical results that are pertinent to the Ferrocyanide Safety Issue. This document compares the analytical results with the data requirements for ferrocyanide tanks as documented in Data Requirements of the Ferrocyanide Safety Issue Developed Through the Data Quality Objectives Process (Meacham et al. 1994) and provides an assessment of the safety condition of the tank. Analytes not listed in the Data Quality Objectives (DQO) document (Meacham et al. 1994) or not pertinent to the Ferrocyanide Safety Issue are not discussed in this report. Complete documentation of the analytical results can be found in the data package for the tank 241-T-107 cores (Svancara and Pool 1993). A more complete evaluation of the analytical results and an estimate of the tank inventory will be provided in a forthcoming tank characterization report for tank 241-T-107.
FRACTIONAL CRYSALLIZATION LABORATORY TESTS WITH SIMULATED TANK WASTE
2007-11-29
Results are presented for several simulated waste tests related to development of the fractional crystallization process. Product salt dissolution rates were measured to support pilot plant equipment design. Evaporation tests were performed to evaluate the effects of organics on slurry behavior and to determine optimum antifoam addition levels. A loss-of-power test was performed to support pilot plant accident scenario analysis. Envelope limit tests were done to address variations in feed composition.
Enhanced Beetle Luciferase for High-Resolution Bioluminescence Imaging
We developed an enhanced green-emitting luciferase (ELuc) to be used as a bioluminescence imaging (BLI) probe. ELuc exhibits a light signal in mammalian cells that is over 10-fold stronger than that...Full Text Available
Enhanced Beetle Luciferase for High-Resolution Bioluminescence Imaging
Full Text Available.We developed an enhanced green-emitting luciferase (ELuc) to be used as a bioluminescence imaging (BLI) probe. ELuc exhibits a light signal in mammalian cells that is over 10-fold stronger than that of the firefly luciferase (FLuc), which is the most widely used luciferase reporter gene. We showed that ELuc produces a strong light signal in primary cells and tissues and that it enables the visualization of gene expression with high temporal resolution at the single-cell level. Moreover, we successfully imaged the nucleocytoplasmic shuttling of importin α by fusing ELuc at the intracellular level. These results demonstrate that the use of ELuc allows a BLI spatiotemporal resolution far greater than that provided by FLuc.
1979-01-01
Separate abstracts have been prepared for the individual papers. (TFD)
2008-01-01
Full Text Available.BackgroundThis study evaluated the therapeutic efficacy of combining vascular disrupting agents with antiangiogenic agents.Materials and MethodsHuman clear cell renal carcinoma (Caki-1) tumors were established in nude mice. Treatments consisted of Avastin (2 mg/kg) administered twice a week; CA4P (100 mg/kg) or OXi4503 (25 mg/kg) administered 3 times a week for a period of 2 weeks; or a combination of Avastin and CA4P or OXi4503. Tumor response was assessed by growth delay.ResultsThe tumor growth delays were 8, 6, and 18 days for Avastin, CA4P, and OXi4503, respectively. When the two therapies were combined, there was a significantly greater tumor response than what was achieved with single-agent treatments. For example, Avastin plus CA4P led to a growth delay of 13 days, and 27 days for Avastin plus OX14503.ConclusionVascular-directed therapies that include both antiangiogenic and vascular disrupting therapeutics can result in significantly enhanced antitumor effects.
2008-01-01
BackgroundThis study evaluated the therapeutic efficacy of combining vascular disrupting agents with antiangiogenic agents.Full Text Available
Determination of silver nanoparticle release from antibacterial fabrics into artificial sweat
Silver nanoparticles have been used in numerous commercial products, including textiles, to prevent bacterial growth. Meanwhile, there is increasing concern that exposure to these nanoparticles may...Full Text Available
Determination of silver nanoparticle release from antibacterial fabrics into artificial sweat
Full Text Available.Silver nanoparticles have been used in numerous commercial products, including textiles, to prevent bacterial growth. Meanwhile, there is increasing concern that exposure to these nanoparticles may cause potential adverse effects on humans as well as the environment. This study determined the quantity of silver released from commercially claimed nanosilver and laboratory-prepared silver coated fabrics into various formulations of artificial sweat, each made according to AATCC, ISO and EN standards. For each fabric sample, the initial amount of silver and the antibacterial properties against the model Gram-positive (S. aureus) and Gram-negative (E. coli) bacteria on each fabric was investigated. The results showed that silver was not detected in some commercial fabrics. Furthermore, antibacterial properties of the fabrics varied, ranging from 0% to greater than 99%. After incubation of the fabrics in artificial sweat, silver was released from the different fabrics to varying extents, ranging from 0 mg/kg to about 322 mg/kg of fabric weight. The quantity of silver released from the different fabrics was likely to be dependent on the amount of silver coating, the fabric quality and the artificial sweat formulations including its pH. This study is the unprecedented report on the release of silver nanoparticles from antibacterial fabrics into artificial sweat. This information might be useful to evaluate the potential human risk associated with the use of textiles containing silver nanoparticles.
DEVELOPMENT OF IMMUNOAFFINITY RESTRICTED ACCESS MEDIA FOR RAPID EXTRACTIONS OF LOW MASS ANALYTES
2008-11-15
Restricted access media using antibodies as immobilized ligands were developed for the rapid and selective capture of small analytes by immunoextraction, giving rise to materials referred to...Full Text Available
DEVELOPMENT OF IMMUNOAFFINITY RESTRICTED ACCESS MEDIA FOR RAPID EXTRACTIONS OF LOW MASS ANALYTES
2008-11-15
Full Text Available.Restricted access media using antibodies as immobilized ligands were developed for the rapid and selective capture of small analytes by immunoextraction, giving rise to materials referred to as immunoaffinity restricted access media (IA-RAM). To make such a material, intact antibodies for the desired target were first immobilized onto porous silica, with antibodies at or near the outer surface of the support then being treated with papain (or a related agent) to release and remove their binding domains. The result was a support in which only antibodies deep within the pores remained intact and able to bind to the target. Items evaluated in the development of such media included the immobilization method used for the antibodies, the pore size of the support, and the amount of papain and time that were used for support treatment. A theoretical model was also developed to describe the extent of binding domain removal based on the measured polypeptide content of the IA-RAM support before and after treatment with papain. The final optimized conditions for making the IA-RAM supports were used to prepare columns that contained anti-fluorescein antibodies. Injections of fluorescein and fluorescein-labeled bovine serum albumin onto these IA-RAM columns gave selective and quantitative extraction of fluorescein in 1-2 s. This approach can be used with other antibodies and low mass targets and should be valuable for such applications as the rapid separation of drugs from drug-protein complexes or the isolation of labeled/modified peptides from intact proteins that contain the same modification or label.
1993-11-01
The coordination chemistry and solution behavior of the toxic ions lead(II) and plutonium(IV, V, VI) have been investigated. The ligand pK{sub a}s and ligand-lead(II) stability constants of one hydroxamic acid and four thiohydroaxamic acids were determined. Solution thermodynamic results indicate that thiohydroxamic acids are more acidic and slightly better lead chelators than hydroxamates, e.g., N-methylthioaceto-hydroxamic acid, pK{sub a} = 5.94, log{beta}{sub 120} = 10.92; acetohydroxamic acid, pK{sub a} = 9.34, log{beta}{sub l20} = 9.52. The syntheses of lead complexes of two bulky hydroxamate ligands are presented. The X-ray crystal structures show the lead hydroxamates are di-bridged dimers with irregular five-coordinate geometry about the metal atom and a stereochemically active lone pair of electrons. Molecular orbital calculations of a lead hydroxamate and a highly symmetric pseudo octahedral lead complex were performed. The thermodynamic stability of plutonium(IV) complexes of the siderophore, desferrioxamine B (DFO), and two octadentate derivatives of DFO were investigated using competition spectrophotometric titrations. The stability constant measured for the plutonium(IV) complex of DFO-methylterephthalamide is log{beta}{sub 110} = 41.7. The solubility limited speciation of {sup 242}Pu as a function of time in near neutral carbonate solution was measured. Individual solutions of plutonium in a single oxidation state were added to individual solutions at pH = 6.0, T = 30.0, 1.93 mM dissolved carbonate, and sampled over intervals up to 150 days. Plutonium solubility was measured, and speciation was investigated using laser photoacoustic spectroscopy and chemical methods.
2008-09-01
Tetrocarcin A (TCA), produced by Micromonospora chalcea NRRL 11289, is a spirotetronate antibiotic with potent antitumor activity and versatile modes of action. In this study, the biosynthetic...Full Text Available
2008-09-01
Full Text Available.Tetrocarcin A (TCA), produced by Micromonospora chalcea NRRL 11289, is a spirotetronate antibiotic with potent antitumor activity and versatile modes of action. In this study, the biosynthetic gene cluster of TCA was cloned and localized to a 108-kb contiguous DNA region. In silico sequence analysis revealed 36 putative genes that constitute this cluster (including 11 for unusual sugar biosynthesis, 13 for aglycone formation, and 4 for glycosylations) and allowed us to propose the biosynthetic pathway of TCA. The formation of d-tetronitrose, l-amicetose, and l-digitoxose may begin with d-glucose-1-phosphate, share early enzymatic steps, and branch into different pathways by competitive actions of specific enzymes. Tetronolide biosynthesis involves the incorporation of a 3-C unit with a polyketide intermediate to form the characteristic spirotetronate moiety and trans-decalin system. Further substitution of tetronolide with five deoxysugars (one being a deoxynitrosugar) was likely due to the activities of four glycosyltransferases. In vitro characterization of the first enzymatic step by utilization of 1,3-biphosphoglycerate as the substrate and in vivo cross-complementation of the bifunctional fused gene tcaD3 (with the functions of chlD3 and chlD4) to ΔchlD3 and ΔchlD4 in chlorothricin biosynthesis supported the highly conserved tetronate biosynthetic strategy in the spirotetronate family. Deletion of a large DNA fragment encoding polyketide synthases resulted in a non-TCA-producing strain, providing a clear background for the identification of novel analogs. These findings provide insights into spirotetronate biosynthesis and demonstrate that combinatorial-biosynthesis methods can be applied to the TCA biosynthetic machinery to generate structural diversity.
1993-07-01
Polystyrene divinylbenzene was modified by acetyl, sulfonic acid, and quaternary ammonium groups. A resin functionalized with an acetyl group was impregnated in a PTFE membrane and used to extract and concentrate phenolic compounds from aqueous samples. The acetyl group created a surface easily wetted, making it an efficient adsorbent for polar compounds in water. The membrane stabilized the resin bed. Partially sulfonated high surface area resins are used to extract and group separate an aqueous mixture of neutral and basic organics; the bases are adsorbed electrostatically to the sulfonic acid groups, while the neutraons are adsorbed hydrophobically. A two-step elution is then used to separate the two fractions. A partially functionalized anion exchange resin is used to separate organic acids and phenols from neutrals in a similar way. Carboxylic acids are analyzed by HPLC and phenols by GC.
Characterization and localization of side population cells in the lens
PurposeSide population (SP) cells were isolated and the possibility whether lens epithelial cells contain stem cells was investigated.MethodsMouse...Full Text Available
Characterization and localization of side population cells in the lens
Full Text Available.PurposeSide population (SP) cells were isolated and the possibility whether lens epithelial cells contain stem cells was investigated.MethodsMouse lens epithelial cells were stained by Hoechst 33342 and then sorted by fluorescence-activated cell sorting (FACS). The expression of stem cell markers in sorted SP cells and the main population of epithelial cells were analyzed by quantitative real-time PCR. Localization of SP cells in the mouse lens was studied by fluorescence microscopy.ResultsThe sorted cells contained SP cells, which were no longer separable by FACS following treatment with verapamil. The number of SP cells decreased with aging, but the adult mouse lens still contained SP cells. Phase contrast microscopy revealed that SP cells were smaller in size than non-SP cells. SP cells were localized near the equator region in lens epithelial cell layers. SP cells expressed higher levels of the stem cell markers ATP-binding cassette transporter G2 (ABCG2), p75 neurotrophin receptor (p75NTR), nestin (nes), B-cell lymphoma 2 (Bcl2), and cell surface antigen Sca-1 mRNA than the main population cells. These results suggest that SP cells contain a high proportion of stem cells.ConclusionsThe SP cells in the lens contain stem cells, and these stem cells are localized around the germinative zone.
CLC3 IS A CRITICAL REGULATOR OF THE CELL CYCLE IN NORMAL AND MALIGNANT GLIAL CELLS
2008-09-10
While most brain cells are post-mitotic, small populations of progenitor or stem cells can divide throughout life. These cells are believed to be the most likely source for primary brain malignancies...Full Text Available
CLC3 IS A CRITICAL REGULATOR OF THE CELL CYCLE IN NORMAL AND MALIGNANT GLIAL CELLS
2008-09-10
Full Text Available.While most brain cells are post-mitotic, small populations of progenitor or stem cells can divide throughout life. These cells are believed to be the most likely source for primary brain malignancies including gliomas. Such tumors share many common features with non-malignant glial cells but owing to their insidious growth form cancers that are typically incurable. In studying the growth regulation of these tumors, we recently discovered that glioma cell division is preceded by a cytoplasmic condensation that we called pre-mitotic condensation (PMC). PMC represents an obligatory step in cell replication and is linked to chromatin condensation. If perturbed, the time required to complete a division is significantly prolonged. We now show that PMC is a feature shared more commonly among normal and malignant cells and that the reduction of cell volume is accomplished by Cl− efflux through ClC3 Cl− channels. Patch-clamp electrophysiology demonstrated a significant upregulation of chloride currents at M phase of the cell cycle. Colocalization studies and co-immunoprecipitation experiments showed the channel on the plasma membrane and at the mitotic spindle. In order to demonstrate a mechanistic role for ClC3 in PMC we knocked down ClC3 expression using shRNA constructs. This resulted in a significant reduction of chloride currents at M-phase that was associated with a decrease in the rate of PMC and a similar impairment of DNA condensation. This data suggests that PMC is an integral part of cell division and is dependent on ClC3 channel function.
BIO-ORGANIC CHEMISTRY QUARTERLY REPORT. March through05/1963
1963-07-23
This report covers the following titles: (1) Fertility and litter size of normally ovulated and artificially ovulated mice; (2) Further studies on sterility produced in male mice by deuterium oxide; (3) Planarian disaggregation; (4) Uptake of organic compounds by planarians. II; (5) Effects of environmental complexity and training on acetylcholinesterase and cholinesterase activity in rat brain; (6) Effects of environmental complexity and training on brain chemistry and anatomy among mature rats; (7) Improvements in paper chromatographic techniques for labeled cell extracts; (8) measurement and adjustment of pH in small volumes of solutions; (9) Carbon-14 and Nitrogen-15 tracer studies of amino acid synthesis during photosynthesis by Chlorella Pyrenoidosa; (10) Photosynthesis of {sup 14}C-labeled protein from {sup 14}CO{sub 2} by Chlorella; (11) Further studies on carboxydismutase; (12) Electron microscopy of chlorophyll a crystals; (13) The possible role of chromanyl phosphates in oxidative and photosynthetic phosphorylation; (14) Oxidation-reductions of some coenzymes; (15) Preparation of some [{sup 14}C] labeled substances: glucose-6-phosphate, fructose-6-phosphate, 6-phosphogluconic acid, pyruvic acid, and succinic acid; (16) attempt to synthesize high molecular weight polynucleotides using Schramm's purely chemical method; and (17) Optical properties of some dye-polyanion complexes.
Alternatively spliced isoforms of TRIP8b differentially control h channel trafficking and function
2009-05-13
Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (h channels) are the molecular basis for the current, Ih, which contributes crucially to intrinsic neuronal excitability....Full Text Available
Alternatively spliced isoforms of TRIP8b differentially control h channel trafficking and function
2009-05-13
Full Text Available.Hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (h channels) are the molecular basis for the current, Ih, which contributes crucially to intrinsic neuronal excitability. The subcellular localization and biophysical properties of h channels govern their function, but the mechanisms controlling these characteristics, and especially the potential role of auxiliary subunits or other binding proteins remain unclear.We focused on TRIP8b, an h channel-interacting protein that colocalizes with HCN1 in cortical and hippocampal pyramidal neuron dendrites, and found that it exists in multiple alternative splice variants with distinct effects on h channel trafficking and function. The developmentally-regulated splice variants of TRIP8b all shared dual, C-terminus-located interaction sites with HCN1. When coexpressed with HCN1 in heterologous cells individual TRIP8b isoforms similarly modulated gating of Ih, causing a hyperpolarizing shift in voltage-dependence of channel activation, but differentially upregulated or downregulated Ih current density and HCN1 surface expression. In hippocampal neurons, coexpression of TRIP8b isoforms with HCN1 produced isoform-specific changes of HCN1 localization. Interestingly, the TRIP8b isoforms most abundant in the brain are those predicted to enhance h channel surface expression. Indeed, shRNA knockdown of TRIP8b in hippocampal neurons significantly reduced native Ih. Thus, although TRIP8b exists in multiple splice isoforms, our data suggest that the predominant role of this protein in brain is to promote h channel surface expression and enhance Ih. Because Ih expression is altered in models of several diseases, including temporal lobe epilepsy, TRIP8b may play a role in both normal neuronal function and in aberrant neuronal excitability associated with neurological disease.
Full Text Available.BackgroundOur earlier studies have shown that red blood cell (RBC) morphology in Alzheimer's disease (AD) subjects was altered (> 15% of the RBCs were elongated as compared to 5.9% in normal controls (p < 0.0001)). These results suggested alterations in the RBC membrane architecture in AD subjects, possibly due to RBC-β-amyloid interactions and/or changes in the expression of membrane proteins. We hypothesized that the observed changes could be due to changes in the level of the protein components of the cytoskeleton and those linked to the RBC membrane. To examine this, we performed a proteomic analysis of RBC membrane proteins of AD subjects, and their age-matched controls using one pool of samples from each group, following their separation by SDS-PAGE, in-gel Tryptic digestion, LC-MS-MS of peptides generated, and a label-free approach of semi-quantitative analysis of their relative MS spectral intensities.ResultsThe data suggest, (1) RBC shape/morphology changes in AD subjects are possibly attributed primarily to the changes (elevation or decrease) in the level of a series of membrane/cytoskeleton proteins involved in regulating the stability and elasticity of the RBC membrane, and (2) changes (elevation or decrease) in the level of a second series of proteins in the RBC membrane proteome reflect similar changes reported earlier by various investigators in AD or animal model of AD. Of particular interest, elevation of oxidative stress response proteins such as heat shock 90 kDa protein 1 alpha in AD subjects has been confirmed by western blot analysis in the RBC membrane proteome.ConclusionsThe results suggest that this study provides a potential link between the alterations in RBC membrane proteome in AD subjects and AD pathology.
BackgroundOur earlier studies have shown that red blood cell (RBC) morphology in Alzheimer's disease (AD) subjects was altered (> 15% of the RBCs were elongated as compared...Full Text Available
2008-11-01
We have discovered that adult thalamocortical relay neurones exhibit a sustained enhancement of synaptic inhibition triggered by transient action potential firing of a single thalamic relay neurone....Full Text Available
2008-11-01
Full Text Available.We have discovered that adult thalamocortical relay neurones exhibit a sustained enhancement of synaptic inhibition triggered by transient action potential firing of a single thalamic relay neurone. The sustained activity-dependent increase in IPSC frequency (+48.3 ± 11.4%, n = 32) was blocked by chelating calcium inside an individual cell, by scavenging nitric oxide or by blocking NMDA receptor activation in the thalamus. Surprisingly, the tonic inhibition that is known to result from extrasynaptic GABAA receptor activation in these cells was unaffected by this local form of plasticity. However, tonic inhibition was increased (+ 131.9 ± 56.5%, n = 13) following widespread changes in GABA release across the thalamus. These data suggest that thalamocortical sleep-state oscillations requiring membrane hyperpolarization will be influenced by global sensing of GABA release acting through extrasynaptic GABAA receptors. In contrast, local changes in GABA release of the type observed following this novel form of activity-dependent plasticity will influence local integration of sensory information without changing levels of tonic inhibition.
2008-02-01
Site-specifically modified 2′-methylseleno RNA represents a valuable derivative for phasing of X-ray crystallographic data. Several successful applications in three-dimensional structure determination...Full Text Available
2008-02-01
Full Text Available.Site-specifically modified 2′-methylseleno RNA represents a valuable derivative for phasing of X-ray crystallographic data. Several successful applications in three-dimensional structure determination of nucleic acids, such as the Diels–Alder ribozyme, have relied on this modification. Here, we introduce synthetic routes to 2′-methylseleno phosphoramidite building blocks of all four standard nucleosides, adenosine, cytidine, guanosine and uridine, that are tailored for 2′-O-bis(acetoxyethoxy)methyl (ACE) RNA solid-phase synthesis. We additionally report on their incorporation into oligoribonucleotides including deprotection and purification. The methodological expansion of 2′-methylseleno labeling via ACE RNA chemistry is a major step to make Se-RNA generally accessible and to receive broad dissemination of the Se-approach for crystallographic studies on RNA. Thus far, preparation of 2′-methylseleno-modified oligoribonucleotides has been restricted to the 2′-O-[(triisopropylsilyl)oxy]methyl (TOM) and 2′-O-tert-butyldimethylsilyl (TBDMS) RNA synthesis methods.
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