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Biomedical subjects

R S Ledley

Publications and source records attributed to R S Ledley.

At least 19 recordsLinked to original sources
PubMed1984

Sex differences in blood protein patterns: a computer-assisted electrophoretic analysis of mid-molecular weight range proteins of human serum.

We have studied the sexual dimorphism of human serum proteins between the ranges of approximately 60,000 and 150,000 daltons using computerized imaging and densitometry. Methodology is presented, based on the TEXAC computer system for the detection, segmentation and integration of protein bands. The results are discussed in terms of potential future applications in computerized medical diagnosis.

Adolescent↗
PubMed1984

Aldehyde-induced platelet aggregation.

Formaldehyde, acetaldehyde, malondialdehyde, glutaraldehyde and paraldehyde, when added in vitro to platelet-rich plasma, generate a similar distinct platelet aggregation response which is dose dependent when measured with a manual visual microscopic technique and by computerized image analysis, 'computerized platelet aggregation analysis'. Light transmission aggregometry did not measure this aggregation in a reliable manner. The aggregating reaction was specific to the aldehyde group and was not seen when the aldehyde was replaced by an alcohol, ketone, or acetate group in the case of acetaldehyde. The maximal aggregating effect of these aldehydes was directly proportional to the number of aldehyde groups per molecule. Aggregation was found to require the presence of plasma, but not von Willebrand's factor.

Acetaldehyde↗
PubMed1983

Computer applications in analysis, mapping and cataloging of proteins separated by two dimensional electrophoresis.

Two dimensional electrophoretic separation of complex mixtures of proteins can only be exploited to its fullest potential using sophisticated computerized spot detection, quantification, pattern recognition, pattern normalization, data reduction and data storage. We present a discussion of some of the technical problems and of the options available which will ultimately lead toward full computerization of the data.

Computers↗
PubMed1983

Cost containment in the concentrated care center: a study of nursing, bed and patient assignment policies.

In an effort to deliver the best possible care to seriously ill patients in the most cost-effective manner, Georgetown University has developed the Concentrated Care Center (CCC) as an essential component of the medical center complex. The design of the CCC, together with the application of controlled variable staffing procedures, permits considerable flexibility in the assignment of nurses (as well as patients) to individual units. This report outlines certain research hypotheses regarding policies designed to increase the cost-effectiveness of patient care in the CCC environment. Statistical techniques based on the theory of stochastic processes are developed to test these hypotheses and a FORTRAN IV computer program is developed to analyze one year of operational data from the CCC.

Computers↗
PubMed1982

Decision theory model of the emergency medical triage process.

The major objective of this research project was to apply the scientific discipline of decision-making to the problem of identifying the appropriate receiving hospital for persons injured in accidents. This problem, which is usually referred to as the prehospital triage process, is enormously important in terms of maximizing the critically injured patient's chances for survival. The long term objective of this research program, for which this project was a pilot study, is to develop an interactive computer system to support decisions regarding triage of patients at the scene of medical emergencies. The completed system will offer guidance to the paramedic in deciding whether to transport the emergency victim to the nearest hospital for stabilization and further evaluation or directly to the hospital best equipped to deal with the specific conditions of the victim.

Accidents↗
PubMed1982

CT techniques.

Since the advent of whole-body CT scanning in 1974, many studies have been made in its application to all parts of the body. One of the most fruitful areas has been CT of the spinal cord. The only limitation appears to be the technique used; there is no substitute for a good technique. We shall first review standard CT techniques, then mention special techniques for spinal cord work, and finally discuss the future.

Diagnosis, Differential↗
PubMed1980

Albumin obscures sex differences in blood protein patterns of rats and humans.

Sex related differences in the blood protein patterns of male and female rats and humans have been studied by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. In rats, a prominent band of mol.wt. 74000--78000 is seen in females in far greater quantity than in males, castrated males or ovariectomized females. A secondary band of 100000 is seen under non-reducing conditions in female rats that is absent in males. In humans, bands of 92000 and 88000 mol.wt. appear to be variable in concentration in men although relatively constant in women. The above differences are observable only if serum albumin is removed from the samples before electrophoresis. The results suggest that each sex has its own characteristic blood protein pattern.

Adolescent↗
PubMed1979

Application of the ACTA-scanner to visualization of the spine.

The development of a new computer program called VISUAL, designed to be applied to a series of cross-sectional ACTA scans of the body, makes possible the three-dimensional visulaization of spinal structure without the necessity of surgical exploration. With VISUAL, a molded three-dimensional image of the spine can be displayed on a CT scanner monitor from any of several angles, or from several angles successively, with the direction of illumination determined by the operator.

Computers↗
PubMed1978

Medical technology and cost containment: two applications of operations research.

The government proposes "common sense" regulations to help contain rising health costs due to the increasing use of high-technology procedures, such as computerized tomography scanning. Two illustrations are given showing that such ad hoc regulations may have the effect of increasing costs and are certainly far from the optimum obtained by known methods of operations research.

Computers↗
PubMed1978

Evaluation of calcium concentration in bones from CT scans.

Fresh cadaveric lumbar vertebrae from 28 subjects were obtained at autopsies and then analyzed by CT scans. An average CT number, calibrated against water and representing the relative x-ray attenuation coefficient of cancellous bone of each vertebra, was obtained. Calcium concentrations in milligrams per cubic centimeter for each vertebral specimen, calculated by physical methods, were plotted against the average CT numbers. The results suggest a linear relationship between the CT numbers and the calcium content of bone.

Adult↗
PubMed1977

Radiotherapy treatment planning using the ACTA-scanner.

Computerized tomography is useful in radiotherapy treatment planning in the following ways: (1) Its image provides the most accurate possible contour of the patient and demonstrates the internal structures in their proper relation to each other. (2) The tumor and its extension are accurately demonstrated. (3) Corrections for tissue heterogeneities can be accomplished in one of two ways, either by arbitrary assignment of densities to tissues or by direct scanning with a therapy source. This latter procedure is under investigation. (4) The computer can be programmed to demonstrate summations of dose delivered from multiple fields.

Dose-Response Relationship, Radiation↗
PubMed1977

A forthcoming cross-sectional atlas correlating CT scans with anatomical structures.

With the development of the whole-body CAT (computerized axial tomographic) scanner, a need has arisen for a cross-sectional anatomy book that correlates acutal CT scans with detailed anatomical structures. This article describes a forthcoming cross-sectional atlas using CT scans of normal living human volunteers. After a preliminary discussion of such considerations as some fundamental differences between cross-sectional anatomy and conventional anatomy and the relationship between cross-sectional anatomy and computerized tomography, there is an explanation of the textual format. This section includes a description of the presentations on the pages, the use of color in the scans, and the use of certain advanced features of the ACTA-Scanner, the scanner used for the atlas. The final part of the article illustrates sample scans and a diagram from the forthcoming test.

Anatomy↗