Search results for "dosage"
showing 10 items of 516 documents
Low dose CT of the heart: a quantum leap into a new era of cardiovascular imaging.
2010
In 10 years, computed tomography coronary angiography (CTCA) has shifted from an investigational tool to clinical reality. Even though CT technologies are very advanced and widely available, a large body of evidence supporting the clinical role of CTCA is missing. The reason is that the speed of technological development has outpaced the ability of the scientific community to demonstrate the clinical utility of the technique. In addition, with each new CT generation, there is a further broadening of actual and potential applications. In this review we examine the state of the art on CTCA. In particular, we focus on issues concerning technological development, radiation dose, implementation,…
CT coronary angiography at an ultra-low radiation dose (< 0.1 mSv): feasible and viable in times of constraint on healthcare costs
2013
Computed tomography coronary angiography (CTCA) has reached very high standards both in terms of diagnostic performance and radiation dose reduction. This commentary follows a report on CTCA using less than 0.1 mSv in selected patients. This is an extraordinary accomplishment, both for technology and for medicine. The difficult task is now to implement this tool in clinical practice so it can play the best possible role. CTCA can improve diagnostic pathways, can save money for healthcare systems and could even improve pharmacological therapy. All of this may happen, but it will require the combined effort of all the experienced operators in this field, including the referring clinicians. In…
Quantification of a novel group of nitrate-reducing bacteria in the environment by real-time PCR
2004
Abstract Nitrate reduction is performed by phylogenetically diverse bacteria. Analysis of narG (alpha subunit of the membrane bound nitrate reductase) trees constructed using environmental sequences revealed a new cluster that is not related to narG gene from known nitrate-reducing bacteria. In this study, primers targeting this as yet uncultivated nitrate-reducing group were designed and used to develop a real-time SYBR® Green PCR assay. The assay was tested with clones from distinct nitrate-reducing groups and applied to various environmental samples. narG copy number was high ranging between 5.08×108 and 1.12×1011 copies per gram of dry weight of environmental sample. Environmental real-…
A cluster of cuticle protein genes of Drosophila melanogaster at 65A: sequence, structure and evolution
1997
0016-6731 (Print) Journal Article Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, Non-P.H.S.; A 36-kb genomic DNA segment of the Drosophila melanogaster genome containing 12 clustered cuticle genes has been mapped and partially sequenced. The cluster maps at 65A 5-6 on the left arm of the third chromosome, in agreement with the previously determined location of a putative cluster encompassing the genes for the third instar larval cuticle proteins LCP5, LCP6 and LCP8. This cluster is the largest cuticle gene cluster discovered to date and shows a number of surprising features that explain in part the genetic complexity of the LCP5, LCP6 and LCP8 loci. The genes encoding LCP5 a…
Spectrophotometric estimation of bicalutamide in tablets
2007
A simple, sensitive, rapid, accurate and precise spectrophotometric method has been developed for the estimation of bicalutamide in bulk and pharmaceutical dosage forms. Bicalutamide shows maximum absorbance at 272 nm with molar absorptivity of 2.3399×10(4) l/mol/cm. Beer's law was obeyed in the concentration range of 1.5-18 μg/ml. The limit of detection and limit of quantification were found to be 0.1 and 0.4 μg/ml, respectively. Results of analysis were validated statistically and by recovery studies.
Spectrofluorimetric Determination of Iproniazid and Isoniazid in a FIA System Provided with a Solid-Phase Reactor
1998
Abstract A FIA assembly is proposed for the fluorimetric determination of iproniazid and isoniazid. The oxidation of both drugs is carried out by H2O2. The excess of reagent is destroyed and removed from the flow-injection manifold by means of a metallic copper reactor which acts as catalyst in the decomposition of H2O2 and a home made debubbler. The calibration graphs were linear up to 14 μg ml−1 and 10 μg ml−1 (n=6) for iproniazid and isoniazid, respectively, with limits of detection of 0.008 μg ml−1 and 0.005 μg ml−1. The sample throughput was 24 h−1 for both drugs. The influence of foreign compounds was studied and the procedure was applied to determination of iproniazid and isoniazid i…
FI-on line photochemical reaction for direct chemiluminescence determination of photodegradated chloramphenicol.
2002
Abstract A new, simple, clean and selective flow injection strategy based on the tandem photochemical reaction-chemiluminescence detection was applied to the determination of chloramphenicol. The determination is based on the on-line photodegradation of the drug in a glycine buffer at pH 8.8 by using a photoreactor consisting of 697 cm×0.5 mm PTFE tubing helically coiled around an 8 W low-pressure mercury lamp. Photodegradated chloramphenicol is detected by direct chemiluminescence of resulting photo-fragments and their subsequent reaction with potassium permanganate in sulfuric acid medium as oxidant. The method allows the chemiluminescence determination of compounds which do not exhibit n…
Use of micellar mobile phases for the chromatographic determination of clorazepate, diazepam, and diltiazem in pharmaceuticals
2001
An ODS-2 column, a micellar mobile phase of high elution strength containing 0.1M sodium dodecyl sulfate and 3% (v/v) butanol, and ultraviolet detection at 230 nm are used for the determination of either of two benzodiazepines (clorazepate and diazepam) and a benzothiazepine (diltiazem) in pharmaceuticals. The procedure is shown to be competitive against conventional chromatography with methanol-water mobile phases, especially for diltiazem. The composition of the micellar mobile phase is selected using a predictive strategy based on an accurate retention model and assisted by computer simulation. Calibration graphs are linear at least in the 2.5 to 20 microg/mL, 4 to 20 microg/mL, and 5 to…
MICELLAR LIQUID CHROMATOGRAPHIC DETERMINATION OF ANTI-CONVULSANT DRUGS IN PILLS AND CAPSULES
2000
A simple chromatographic procedure is reported for the determination of several anti-convulsant drugs in pharmaceuticals: carbamazepine, and the benzodiazepines bentazepam, halazepam, oxazepam, pinazepam, and tetrazepam. The procedure utilizes a C18 column, a hybrid micellar mobile phase of 0.1 M SDS-3% butanol-0.1% triethylamine-0.01 M phosphate buffer (pH 3), and UV detection (230 nm). The drugs eluted in less than 13 min, in accordance to their relative polarities, as indicated by their octanol-water partition coefficients. The limits of detection (μg/mL), and intra and inter-day repeatabilities (%), for 4 μg/mL were: carbamazepine (0.03, 1.0, 4.1), bentazepam (0.05, 1.3, 1.6), halazepam…
Flow analysis-spectrophotometric determination of ?-dopa in pharmaceutical formulations by reaction with p-Aminophenol
1994
Abstract A new method has been developed for the spectrophotometric determination of l -dopa in pharmaceutical formulations. The method is based on the reaction between the open-chain quinone of l -dopa, obtained in NaOH, and the benzoqinoneimine form of p-aminophenol, in the presence of KIO4. The reaction product is determined at 574 nm by using both alternately procedures, one based on the stopped-flow and another on a flow injection approach. Under the best experimental conditions L-dopa can be determined with a limit of detection of 52 ng/ml and a relative standard deviation of 0.2% for three replicate measurements of a solution containing 4 μg/ml.