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Biomedical subjects

R A Keller

Publications and source records attributed to R A Keller.

13 recordsLinked to original sources
PubMed1991

Rapid DNA sequencing based upon single molecule detection.

We are developing a laser-based technique for the rapid sequencing of 40-kb or larger fragments of DNA at a rate of 100 to 1000 bases per second. The approach relies on fluorescent labeling of the bases in a single fragment of DNA, attachment of this labeled DNA fragment to a support, movement of the supported DNA fragment into a flowing sample stream, and detection of individual fluorescently labeled bases as they are cleaved from the DNA fragment by an exonuclease. The ability to sequence large fragments of DNA will significantly reduce the amount of subcloning and the number of overlapping sequences required to assemble megabase segments of sequence information.

Base Sequence↗
PubMed1989

Characteristics of child sexual abuse treatment programs.

Within the professional community, a vast number of sexual abuse treatment programs have emerged to meet the needs of victims and their families. Significant variations among these programs can be observed due to differences in philosophy, system context, client focus, problem definition, and the treatment strategy adopted. Unfortunately, little comparative information is available regarding the operation of different programs and, more importantly, their relative treatment effectiveness. This article presents the findings from a nationwide survey of 553 sexual abuse treatment programs. The survey focused on program context, client, and service characteristics. Overall it was found that most programs are affiliated with a larger public or private agency, focus on treating victims, and rely on a combination of individual, family, dyad, and group therapy approaches.

Child↗
PubMed1989

High-speed DNA sequencing: an approach based upon fluorescence detection of single molecules.

We are developing a laser based technique for the rapid sequencing of large fragments (approximately 40 kb) of DNA based upon the detection of single, fluorescently tagged nucleotides cleaved from a single DNA fragment. We have demonstrated significant progress on several of the important steps of this technique. The projected rate of sequencing is several hundred bases per second which is orders of magnitude faster than existing methods. Once developed, this technology could be utilized by investigators for rapid sequencing of genetic material from virtually any source.

Base Sequence↗
PubMedDate not supplied

Single-molecule detection as an approach to rapid DNA sequencing.

Current sequencing technologies are insufficient to cope with large-scale projects such as sequencing the human genome and genomes of model organisms. In addition, as genetic lesions associated with specific human diseases are identified, DNA sequencing will be used increasingly for clinical applications. Thus, new approaches are needed to combine high-throughput with accuracy for both research and diagnostic purposes. A novel technology based on detection of individual fluorescent nucleotides in a flowing sample stream is under development.

Animals↗
PubMedDate not supplied

A computer program for the localization of small areas in roentgenological images.

A method and associated algorithm are presented which allow a simple and accurate determination to be made of the location of small symmetric areas presented in roentgenological images. The method utilizes an operator to visually spot object positions but eliminates the need for critical positoning accuracy on the operator's part. The rapidity of measurement allows results to be evaluated on-line. Parameters associated with the algorithm have been analyzed, and methods to facilitate an optimum choice for any particular experimental setup are presented.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

The capability of fluoroscopic systems for the production of computerized axial tomograms.

Previous work in our laboratories and at other institutions has shown that fluoroscopic images recorded on a video disc can be used successfully for producing computerized-axial-tomograms. The work described in this paper gives a quantitative analysis of the capabilities of such imaging systems, in conjunction with a particular method of data processing, for detecting and imaging changes in object absorptivity. Relations between the degree of contrast or absorptivity and object size required by this type of system can be inferred from the data.

Fluoroscopy↗
PubMedDate not supplied

Simple method for the generation of organ and vessel contours from roentgenographic or fluoroscopic images.

A simple method is described for outlining or contouring any area defined by a change in film density or fluoroscopic screen intensity. The entire process, except for the positioning of an electronic window, is accomplished using a small computer having appropriate software. The electronic window is operator positioned over the area to be processed. The only requirement is that the window be alrge enough to encompass the total area to be considered.

Fluoroscopy↗
PubMedDate not supplied

Tumor localization and beam monitoring--electrofluorotomography.

Methodology and instrumentation are presented which are potentially capable of presenting fluoroscopically derived transverse axial body sections for use in radiation-oncology treatment planning and beam monitoring. These combine the methods of Takahashi for generating transverse axial tomograms with electronic radiography, electrofluorotomography, and a contouring program for extracting body and tumor contours in a digital format. The system will also be capable of assuring both initial and day-to-day beam alignment.

Fluoroscopy↗
PubMedDate not supplied

Computerized system for the measurement of gallstone volume, in vivo.

Instrumentation and methodology for the determination of gallstone volume from standard roentgenographic views have been developed. Evaluation of size is made by using video viewing, an operator-set electronic window, intercept registers, and the programming of a PDP/8E for handling the data. The programming makes corrections for geometric factors arising from anatomical variations, corrections for variations in technique, roentgenographic magnification, and provides for the use of several roentgenographic views. The precision of the measuring (video) technique is approximately 0.5 mm as measured on the roentgenogram. Estimates and test data indicate that this system should be capable of an absolute accuracy within 10% of the true volume.

Cholelithiasis↗