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Biomedical subjects

R L Summers

Publications and source records attributed to R L Summers.

29 records · Page 2Linked to original sources
PubMed1997

Medical computing in Mississippi.

As our society enters the information age, physicians are finding an ever growing role for computers in the practice of medicine. Computers are used for education, research, medical record keeping, communications and as a powerful reference resource. They have even served as electronic consultants to assist in diagnosis and medical decision making. Mississippians have been pioneers in the use of computers in research and education and have taken a very progressive view of the future of medical computing in our state. Resources such as the Mississippi Health Sciences Information Network have served to connect rural health practitioners to academic centers and other informational resources and improve the quality of patient care throughout the state. Internet users will find that there are many Mississippi medical institutions that have home pages on the world wide web that also connects us to the global medical community. Computers are rapidly becoming one of the most important new tools in the black bag of the modern physician.

Computer Communication Networks↗
PubMed1996

Graphic analysis for the study of metabolic states.

Graphic analyses have been used in the study of physiology as a means to better understand dynamic processes and to visualize the mechanisms of their interactions. A graphic analysis of glucose homeostasis was constructed by considering the main factors that influence glucose dynamics. The analysis is achieved by equating curves representing both the inflow and outflow of glucose from the circulation as dependent upon the serum insulin concentration. The point where these two curves intersect is the steady-state balance for blood glucose exchange and is termed the equilibrium point. With the use of this graphic depiction of glucose homeostasis, it is now possible to study the influence of multiple factors on glucose dynamics. A variety of metabolic states can also be analyzed by reconstructing the effects of the pathophysiology on the form and shape of the curves. Some of the metabolic states that have been analyzed by this technique include starvation, exercise, obesity, type I and type II diabetes mellitus, stress, hypopituitarism, hyperpituitarism, and hyperthyroidism. Although the analyses do not reflect all of the controversial nuances of the field, they do provide a means for a general approach to the study of glucose homeostasis and serve as a methodology that can be extrapolated to many areas of physiological study.

Audiovisual Aids↗
PubMed1994

Resistance to metabolic actions of insulin and its role in hypertension.

Insulin resistance and hyperinsulinemia have been postulated to be important in raising blood pressure in obese as well as lean hypertensive individuals. However, cause-and-effect relationships among these variables have not been clearly established. The three most widely used methods to assess insulin resistance in vivo (fasting plasma insulin, glucose disposal after a glucose load, or glucose disposal during a hyperinsulinemic euglycemic clamp) may provide different estimates of insulin resistance under various physiological and pathophysiological conditions. Fasting hyperinsulinemia may reflect mainly hepatic insulin resistance, whereas impairment of glucose disposal indicates resistance to the metabolic effects of insulin in skeletal muscle. The importance of these different sites of insulin resistance in the etiology of cardiovascular diseases, however, is still unclear. Although hyperinsulinemia and insulin resistance have been speculated to cause hypertension, most of the evidence supporting this hypothesis has come either from correlation studies or from short-term studies of the cardiovascular, renal, and sympathetic effects of insulin. The few long-term studies that have been conducted in dogs and in humans do not support the insulin concept of hypertension. In fact, these studies suggest that the vasodilator actions of insulin tend to reduce, rather than elevate, blood pressure. Correlations between insulin resistance, hyperinsulinemia, and hypertension do not appear to be explainable by the concept that insulin resistance occurs secondary to hypertension. Obesity may be a key factor in explaining these relationships; weight gain appears to cause insulin resistance, compensatory hyperinsulinemia, and hypertension through parallel, but not necessarily linked, mechanisms. However, insulin resistance and compensatory hyperinsulinemia may contribute to increased risk of other cardiovascular diseases associated with hypertension, such as coronary artery disease.

Animals↗
PubMed1994

Interface for the documentation and compilation of a library of computer models in physiology.

A software interface for the documentation and compilation of a library of computer models in physiology was developed. The interface is an interactive program built within a word processing template in order to provide ease and flexibility of documentation. A model editor within the interface directs the model builder as to standardized requirements for incorporating models into the library and provides the user with an index to the levels of documentation. The interface and accompanying library are intended to facilitate model development, preservation and distribution and will be available for public use.

Computer Simulation↗
PubMed1989

A simulation support system for solving large physiological models on microcomputers.

Although physiological modeling and computer simulation have become useful research tools to test new scientific theories and to design and analyze laboratory experiments, developing a new model can be a tedious process because the investigator must often write very complex and specific routines for data input and output. To facilitate the design of new models (as well as the use of existing models), we have developed MODSIM, a FORTRAN-based simulation support system for the IBM PC computer than can accommodate very large dynamic models having up to several thousand equations. It provides the investigator with utilities for continuous on-line graphical and/or tabular output, as well as facilities for dynamic interaction with the model. The user must only supply a model as a list of mathematical equations written in FORTRAN, along with the initial values of the model variables and parameters. The model is precompiled, compiled, and then linked to the MODSIM utilities. Without further programming, the user can then solve the model, select variables for graphical output, and stop the model at any time to analyze the data or to change a parameter before resuming the simulation. This simulation system makes it very easy to develop new models that actively interact with the experimental research of the investigator.

Computer Simulation↗
PubMed1983

A variant tandemly repeated nucleotide sequence in Balbiani ring 2 of Chironomus tentans.

pCtBR2-2 is a genomic clone from Chironomus tentans that hybridized in situ to Balbiani ring 2 (BR2) on salivary gland polytene chromosome IV. DNA sequencing indicated that the insert contained nearly four copies of a 180 bp tandemly repeated nucleotide sequence that was distinctly different from a previously reported BR2 repeat. Sequence titration experiments detected about 70 copies of the 180 bp repeat per haploid genome, which would correspond to approximately 34% of a 37 kb BR2 gene. Each 180 bp repeat included a conserved 90 bp segment whose sequence was internally nonrepeating (INR), and a variable 90 bp repeated (R) segment comprised of three 30 bp repeats that may have evolved from a 9 bp consensus sequence. Results presented here raise the distinct possibility that other BR genes may contain significantly different repeated sequences that have not been identified.

Amino Acid Sequence↗
PubMedDate not supplied

The use of chemical restraint in helicopter transport.

INTRODUCTION: Helicopter transport of the combative patient is a major safety hazard facing air medical teams. Although physical restraints alone are helpful, the addition of chemical restraint (CR) often is necessary to control these patients while in flight. METHODS: A survey was conducted to determine the current practices of using nonparalyzing CR in air medical transport programs nationwide. The survey consisted of 24 questions on the use of CR during transport. Each U.S. program belonging to the Association of Air Medical Services was contacted by telephone, and a flight nurse or paramedic provided answers based on personal experience and statistics compiled by his or her individual program. RESULTS: Of the 100 programs responding, benzodiazepines were used most commonly to control agitation with 51% using micazolam. Patients with a head injury required CR more frequently than any other condition (73%). Crews flying larger aircraft reported less need for CR. A physician order was required by only 30% of the programs, but delays infrequently endangered the patient (2%). Only 7% of the responding programs had a patient whose condition deteriorated because of CR. CONCLUSION: CR is necessary in air medical transport. Most programs use short-acting benzodiazepines. Crews in smaller aircraft use CR more frequently, and head injury is the most common condition requiring such restraint.

Air Ambulances↗
PubMedDate not supplied

A national survey of the air medical transport of high-risk obstetric patients.

INTRODUCTION: Air medical transport of high-risk obstetric (HROB) patients can be accomplished and advantageous for neonate survival and maternal morbidity. A survey of U.S. helicopter air medical programs was conducted to determine the frequency and current practices of HROB transport. METHODS: Each program was contacted by telephone, and air medical personnel were asked to answer 12 questions based on personal experience and statistics compiled by their programs. RESULTS: Of the 203 programs surveyed, 133 (66%) provided responses. The mean number of HROB transports was 45.6 per year (4.6% of the mean 995 total transports). Although 83% of the responding programs used the standard flight crew during the HROB transport, only 52% required crew members to maintain neonatal resuscitation certification. Only 56% of the aircraft allow pelvic access in the normal patient configuration. While only 22% of programs have specific HROB launch (dispatch) protocols, 50% reported having obstetricians involved in dispatching flights, and 84% carry tocolytic agents in their drug kit. The greatest concerns included in-flight delivery (60%), inadequate fetal monitoring (6%), and inexperience (5%). CONCLUSION: While HROBs account for 5% of air medical flights, many programs appear to be poorly prepared for these patients.

Air Ambulances↗