Biosciences, Bioengineering, and Pharmaceutical Research

Physicians and scientists from the University of Texas Health Science Center at San Antonio are collaborating with Institute researchers in neurobehavioral studies using the SwRI inhalation dosing laboratory. The team is developing an animal model to examine the problems reported by patients who have been sensitized to volatile chemicals. SwRI staff members are also conducting inhalation dosing and neurotoxicity chemical sensitivity evaluations of toluene according to U.S. Environmental Protection Agency test guidelines.

Institute staff members are involved in a variety of programs related to the diagnosis and treatment of disease, including the development of biomaterials and medical devices, bioengineering and biosciences research, pharmaceutical research, and health and safety testing.

Embossed Braille characters are produced by printers that are typically expensive, noisy, and cumbersome. Through an internal research project, Institute engineers and scientists are testing the feasibility of a low-cost Braille printer that creates extremely durable characters by spraying a fast-drying liquid plastic onto ordinary paper. The improved printer, expected to be faster and quieter than traditional Braille printers, would greatly increase availability of Braille text to the visually impaired.

Optical diagnosis relies on sophisticated signal analysis techniques to extract information from light reflected from organs and tissues, allowing physicians to detect diseases or abnormalities. In the past year, Institute engineers and physicists designed a compact optical analysis system to monitor anesthesia gas delivery in operating rooms and intensive care units. A new optical monitoring technique was also developed to measure the amount of oxygen in the blood. The system employs a small catheter that can be inserted directly into a blood vessel.

Algorithms that calculate blood oxygen saturation were investigated at SwRI using a specialized test apparatus. The apparatus allows control of blood physiological variables that affect oxygen saturation, including pH, temperature, and total hemoglobin. SwRI used the test apparatus to conduct a Good Laboratory Practices performance study of a new oximeter, and the results have been submitted to the Food and Drug Administration (FDA) for review. Institute scientists also plan to use the apparatus to study the biocompatibility of blood substitutes.

The Institute conducts medical device performance and compatibility evaluations with specialized laboratory test systems that simulate physiological conditions. This blood-loop bench test system was used to measure the oxygen saturation and performance of a new patient oximeter with a bench spectrophotometer.

Medical application software is strongly regulated by the FDA in the U.S. and by regulatory agencies such as the European Union internationally. Institute analysts are experienced in both innovative computer software development and applicable critical regulatory issues. In 1996, SwRI provided software specifications for a heart-lung bypass monitor and a pacemaker programmer. Institute researchers also conducted software design and development for a spreadsheet program that automates clinical chemistry data recording, a heat stress monitor, a bedside infusion pump, and a data acquisition system for a cardiac catheterization laboratory. In addition, SwRI developed a cardiac output monitor that is FDA-approved and in use.

The interaction between a pacemaker and a cellular telephone is analyzed in one of SwRI's anechoic chambers. To simulate conditions inside the human body, the pacemaker is immersed in a 37 degrees C saline solution. The pacemaker is exposed to varying levels of electromagnetic energy radiating from a dipole antenna placed in close proximity to the device.

In January 1996, the European Union imposed strict regulations governing the performance of medical instruments in the presence of electromagnetic interference from sources such as cellular telephones and certain medical devices. Since then, in a multidisciplinary effort for the medical electronics industry, SwRI has evaluated, improved, and qualified more than 20 medical instruments for use under the new guidelines. The devices include blood pressure monitors, oximeters, cardiac output computers, and complex multifunction monitors for use in intensive care units and operating rooms.

In response to growing concerns about the effects of cellular telephone use by patients with pacemakers, SwRI cooperated with medical device manufacturers to improve the safety and reliability of the devices. Institute engineers designed test cells that mimic the electromagnetic field strengths produced inside the human body by a cellular phone. Pacemakers and implantable defibrillators underwent performance tests in the cells, and the results were used by manufacturers to improve the implantable devices.

Preclinical safety and efficacy investigations conducted in accordance with Good Laboratory Practice standards provide data for use by the FDA in the testing of new drugs. Many drugs and medical devices are designed to be compatible with human biochemistry and immunology. Consequently, the Institute relies increasingly on nonhuman primates as the biomedical model most closely resembling human physiology.

Preclinical studies are in progress to evaluate the safety of administering drugs directly to the brain. This method may be required in the treatment of serious neurological disorders, in which direct drug administration is needed to circumvent regulatory mechanisms such as blood-brain barriers. Using magnetic resonance imaging to target and verify implant location, SwRI researchers successfully inserted small-diameter intracerebroventricular cannulas in the brains of rhesus monkeys.

Carbon monoxide is the leading cause of death by poisoning in the United States. Researchers at SwRI are establishing a baboon model to test drugs developed to treat carbon monoxide poisoning. Currently, no pharmacological intervention exists, leaving patients with oxygen therapy as their only treatment option. The experimentation requires a specialized inhalation exposure system and continuous monitoring of multiple parameters.

1996 Annual Report SwRI Home