Search PubMed⌕ Search

Biomedical subjects

R Mather

Publications and source records attributed to R Mather.

8 recordsLinked to original sources
PubMed2000

Effect of food on the pharmacokinetics of oral MMI270B (CGS 27023A), a novel matrix metalloproteinase inhibitor.

MMI270B is a matrix metalloproteinase inhibitor (MMPI) with in vitro and in vivo activity. To exert optimal target inhibition, MMPI must be given chronically, and therefore, oral bioavailability is important. We analyzed the effect of food intake on AUC0-8 h, Cmax, and Tmax. Seventeen patients were entered into the study. Doses of MMI270B were 150, 400, and 600 mg. The first day, patients ingested the drug in a fasted state and were not allowed to eat for 2 h. The second day, patients ingested the drug 30 min after a light breakfast. Mean AUC0-8 h was not significantly influenced by food intake. Plasma concentrations were well above the IC50 of several MMPs at all doses tested. Mean Cmax was significantly decreased after food intake. Mean Tmax was significantly delayed after food intake. Food intake did not result in a significant change in exposure to MMI270B (AUC0-8 h) but did result in a significant, although not clinically relevant, decrease in peak plasma levels and time to reach peak plasma levels. No specific guidelines concerning the ingestion of MMI270B in either a fed or a fasted state are recommended.

Administration, Oral↗
PubMed1998

Information frames: a new multimedia approach to Web-based learning of biology and medicine.

Presentation of content in hyperlinked multimedia formats for teaching has failed using the computer's power of navigation through rich visual and auditory information. We have developed "Information Frames", an authoring tool in hypertext markup language (html) format, that allows easy utilization by technology-challenged teachers and professors, and attracts students because of interactive, design-based learning. An Information Frame contains a definition, explanation and illustration of a single concept. Topics are provided with hyperlinks to other Information Frames having related concepts that may provide prerequisite knowledge, or may raise the concept to a more integrative level. A graphical view of the linked-Information Frames presents a Concept Map of the overall topic.

Computer Communication Networks↗
PubMed1997

Coronary artery calcium: alternate methods for accurate and reproducible quantitation.

RATIONALE AND OBJECTIVES: The aim of this study was to determine a more precise and accurate method of quantitating coronary artery calcium (CAC) detected with electron-beam computed tomography (CT) in patients with low CAC scores. MATERIALS AND METHODS: Two 40-section, 3-mm-collimation, electrocardiographically gated electron-beam CT examinations of the heart were performed in each patient. Fifty patients with average scores between 2 and 100, as determined with the conventional scoring algorithm, were selected. The modified conventional scoring algorithm was compared with two techniques: calculated calcium volume and approximated calcium mass. RESULTS: The percentage difference between scans ranged from 37.2% for the conventional scoring method to 28.2% and 28.4% for volume- and mass-based methods, respectively. Increasing lesion size thresholds does not improve quantitative precision and reduces accuracy in patients with small amounts of CAC. CONCLUSION: Quantification methods based on calcification volume or mass decrease score variation compared with the conventional scoring method, and increased size threshold does not improve accuracy.

Adult↗
PubMed1997

Estimation of the left ventricular ejection fraction using a novel multiphase, dark-blood, breath-hold MR imaging technique.

OBJECTIVE: In this paper, we evaluate a recently proposed dual-phase dark-blood MR sequence for estimating the left ventricular ejection fraction, compare Simpson's method of estimation of ejection fraction with a model based on the biplane method, assess the reproducibility of both methods, and finally, test a semiautomated method for contouring the endocardial border. SUBJECTS AND METHODS: An MR pulse sequence was implemented to acquire cardiac images in both diastolic and systolic phases within a single breath-hold. A special magnetization preparation scheme rendered blood dark while a segmented acquisition allowed breath-hold scan times. Five healthy volunteers and five patients with cardiac disease were imaged. Ejection fractions were estimated using (1) long-axis and four-chamber biplane views with an ellipsoid model and (2) a series of short-axis views in combination with Simpson's model. These values of ejection fractions were then compared with values obtained from echocardiography. RESULTS: Estimates of ejection fractions obtained using biplane ellipsoid volume and Simpson's rule methods varied by 14% in healthy volunteers. However, for patients with severe cardiomyopathy, differences between the values of ejection fraction obtained with the two methods varied by as much as 150%. Ejection fraction estimates obtained from MR images with the biplane ellipsoid method and from echocardiography varied by approximately 14% for all subjects. Ejection fraction estimates obtained with the semiautomated algorithm agreed well with estimates obtained with manual contours made by experienced radiologists. Intraobserver variability was low for both the short-axis (3%) and biplane (4%) methods. However, interobserver variability of the biplane method (12%) exceeded that of the short-axis method (4%). Interexamination variability (9%) was the largest factor in determining the reproducibility of the ejection fraction estimates. CONCLUSION: Breath-hold dark-blood MR imaging technique with simultaneous acquisition of a series of short-axis views during systolic and diastolic phases permits rapid and accurate estimates of ejection fractions in healthy subjects and in patients. Model based biplane MR imaging methods are less reliable in patients with global cardiomyopathy. The estimation of ejection fractions can be automated using the proposed contouring algorithm and the dark-blood short-axis views.

Adult↗
PubMed1995

The interactive image tool: adding structure to images.

The interactive image format and tool were developed by the Stanford University Medical Media and Information Technologies (SUMMIT) group to allow medical educators to add interactive annotations and outlines to medical cross-sections, gross dissections, and clinical images. The interactive image tool (IIT) format offers a general specification for adding structural information to images. The IIT format has been used to create rich databases of image/structure information which are employed in educational software created at SUMMIT. These databases consist of information which is re-usable in other applications as well as a standalone image database. Future extensions to the IIT format will provide a means to organize information based on the structure of that information rather than on the arbitrary or haphazard links of current hypertext and hypermedia information networks.

Anatomy↗