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At least 757 records · Page 42

All sources NASA NTRS DOE OSTI

NASA NTRS1992

Large scale crystallization of protein pharmaceuticals in microgravity via temperature change

The major objective of this research effort is the temperature driven growth of protein crystals in large batches in the microgravity environment of space. Pharmaceutical houses are developing protein products for patient care, for example, human insulin, human growth hormone, interferons, and tissue plasminogen activator or TPA, the clot buster for heart attack victims. Except for insulin, these are very high value products; they are extremely potent in small quantities and have a great value per gram of material. It is feasible that microgravity crystallization can be a cost recoverable, economically sound final processing step in their manufacture. Large scale protein crystal growth in microgravity has significant advantages from the basic science and the applied science standpoints. Crystal growth can proceed unhindered due to lack of surface effects. Dynamic control is possible and relatively easy. The method has the potential to yield large quantities of pure crystalline product. Crystallization is a time honored procedure for purifying organic materials and microgravity crystallization could be the final step to remove trace impurities from high value protein pharmaceuticals. In addition, microgravity grown crystals could be the final formulation for those medicines that need to be administered in a timed release fashion. Long lasting insulin, insulin lente, is such a product. Also crystalline protein pharmaceuticals are more stable for long-term storage. Temperature, as the initiation step, has certain advantages. Again, dynamic control of the crystallization process is possible and easy. A temperature step is non-invasive and is the most subtle way to control protein solubility and therefore crystallization. Seeding is not necessary. Changes in protein and precipitant concentrations and pH are not necessary. Finally, this method represents a new way to crystallize proteins in space that takes advantage of the unique microgravity environment. The results from two flights showed that the hardware performed perfectly, many crystals were produced, and they were much larger than their ground grown controls. Morphometric analysis was done on over 4,000 crystals to establish crystal size, size distribution, and relative size. Space grown crystals were remarkably larger than their earth grown counterparts and crystal size was a function of PCF volume. That size distribution for the space grown crystals was a function of PCF volume may indicate that ultimate size was a function of temperature gradient. Since the insulin protein concentration was very low, 0.4 mg/ml, the size distribution could also be following the total amount of protein in each of the PCF's. X-ray analysis showed that the bigger space grown insulin crystals diffracted to higher resolution than their ground grown controls. When the data were normalized for size, they still indicated that the space crystals were better than the ground crystals.

Long, Marianna M.↗

NASA NTRS1993

A Fiber Optic Probe for the Detection of Cataracts

A compact fiber optic probe developed for on-orbit science experiments was used to detect the onset of cataracts, a capability that could eliminate physicians' guesswork and result in new drugs to 'dissolve' or slow down the cataract formation before surgery is necessary. The probe is based upon dynamic light scattering (DLS) principles. It has no moving parts, no apertures, and requires no optical alignment. It is flexible and easy to use. Results are presented for excised but intact human eye lenses. In a clinical setting, the device can be easily incorporated into a slit-lamp apparatus (ophthalmoscope) for complete eye diagnostics. In this set-up, the integrated fiber optic probe, the size of a pencil, delivers a low power cone of laser light into the eye of a patient and guides the light which is backscattered by the protein molecules of the lens through a receiving optical fiber to a photo detector. The non-invasive DLS measurements provide rapid determination of protein crystalline size and its size distribution in the eye lens.

Ansari, Rafat R.↗

NASA NTRS1992

Cortical localization of cognitive function by regression of performance on event-related potentials

This paper demonstrates a new method of mapping cortical localization of cognitive function, using electroencephalographic data. Cross-subject regression analyses are used to identify cortical sites and post-stimulus latencies where there is a high correlation between subjects' performance and their cognitive event-related potential amplitude. The procedure was tested using a mental arithmetic task and was found to identify essentially the same cortical regions that have been associated with such tasks on the basis of research with patients suffering localized cortical lesions. Thus, it appears to offer an inexpensive, noninvasive tool for exploring the dynamics of localization in neurologically normal subjects.

Montgomery, R. W.↗

NASA NTRS1992

A comparison of neural network and fuzzy clustering techniques in segmenting magnetic resonance images of the brain

Magnetic resonance (MR) brain section images are segmented and then synthetically colored to give visual representations of the original data with three approaches: the literal and approximate fuzzy c-means unsupervised clustering algorithms and a supervised computational neural network, a dynamic multilayered perception trained with the cascade correlation learning algorithm. Initial clinical results are presented on both normal volunteers and selected patients with brain tumors surrounded by edema. Supervised and unsupervised segmentation techniques provide broadly similar results. Unsupervised fuzzy algorithms were visually observed to show better segmentation when compared with raw image data for volunteer studies. However, for a more complex segmentation problem with tumor/edema or cerebrospinal fluid boundary, where the tissues have similar MR relaxation behavior, inconsistency in rating among experts was observed.

Hall, Lawrence O.↗

NASA NTRS1992

Human low vision image warping - Channel matching considerations

We are investigating the possibility that a video image may productively be warped prior to presentation to a low vision patient. This could form part of a prosthesis for certain field defects. We have done preliminary quantitative studies on some notions that may be valid in calculating the image warpings. We hope the results will help make best use of time to be spent with human subjects, by guiding the selection of parameters and their range to be investigated. We liken a warping optimization to opening the largest number of spatial channels between the pixels of an input imager and resolution cells in the visual system. Some important effects are not quantified that will require human evaluation, such as local 'squashing' of the image, taken as the ratio of eigenvalues of the Jacobian of the transformation. The results indicate that the method shows quantitative promise. These results have identified some geometric transformations to evaluate further with human subjects.

Juday, Richard D.↗

NASA NTRS1987

Melatonin in human preovulatory follicular fluid

Melatonin, the major hormone of the pineal gland, has antigonadotrophic activity in many mammals and may also be involved in human reproduction. Melatonin suppresses steroidogenesis by ovarian granulosa and luteal cells in vitro. To determine if melatonin is present in the human ovary, preovulatory follicular fluids (n = 32) from 15 women were assayed for melatonin by RIA after solvent extraction. The fluids were obtained by laparoscopy or sonographically controlled follicular puncture from infertile women undergoing in vitro fertilization and embryo transfer. All patients had received clomiphene citrate, human menopausal gonadotropin, and hCG to stimulate follicle formation. Blood samples were obtained by venipuncture 30 rain or less after follicular aspiration. All of the follicular fluids contained melatonim, in concentrations substantially higher than those in the corresponding serum. A positive correlation was found between follicular fluid and serum melatonin levels in each woman; these observations indicate that preovulatory follicles contain substantial amounts of melatonin that may affect ovarian steroidogenesis.

Brzezinski, Amnon↗

NASA NTRS1987

Melatonin in human preovulatory follicular fluid

Melatonin, the major hormone of the pineal gland, has antigonadotrophic activity in many mammals and may also be involved in human reproduction. Melatonin suppresses steroidogenesis by ovarian granulosa and luteal cells in vitro. To determine if melatonin is present in the human ovary, preovulatory follicular fluids (n = 32) from 15 women were assayed for melatonin by RIA after solvent extraction. The fluids were obtained by laparoscopy or sonographically controlled follicular puncture from infertile women undergoing in vitro fertilization and embryo transfer. All patients had received clomiphene citrate, human menopausal gonadotropin, and hCG to stimulate follicle formation. Blood samples were obtained by venipuncture 30 min or less after follicular aspiration. All of the follicular fluids contained melatonin, in concentrations (35.6 plus or minus 4.8 (plus or minus SEM) pg/mL) substantially higher than those in the corresponding serum (10.0 plus or minus 1.4 pg/mL). A positive correlation was found between follicular fluid and serum melatonin levels in each woman (r = 0.770; P less than 0.001). These observations indicate that preovulatory follicles contain substantial amounts of melatonin that may affect ovarian steroidogenesis.

Brzezinski, Amnon↗

NASA NTRS1994

Measuring Intracranial Pressure And Volume Noninvasively

Ultrasonic technique eliminates need to drill into brain cavity. Intracranial dynamics instrument probes cranium ultrasonically to obtain data for determination of intracranial pressure (ICP) and pressure-volume index (PVI). Instrument determines sensitivity of skull to changes in pressure and by use of mechanical device to exert external calibrated pressure on skull. By monitoring volume of blood flowing into jugular vein, one determines change of volume of blood in cranial system. By measuring response of skull to increasing pressure (where pressure increased by tilting patient known amount) and by using cranial blood pressure, one determines intial pressure in cerebrospinal fluid. Once PVI determined, ICP determined.

Cantrell, John H.↗

NASA NTRS1991

Linking medical records to an expert system

This presentation will be done using the IMR-Entry (Intelligent Medical Record Entry) system. IMR-Entry is a software program developed as a front-end to our diagnostic consultant software MEDAS (Medical Emergency Decision Assistance System). MEDAS (the Medical Emergency Diagnostic Assistance System) is a diagnostic consultant system using a multimembership Bayesian design for its inference engine and relational database technology for its knowledge base maintenance. Research on MEDAS began at the University of Southern California and the Institute of Critical Care in the mid 1970's with support from NASA and NSF. The MEDAS project moved to Chicago in 1982; its current progress is due to collaboration between Illinois Institute of Technology, The Chicago Medical School, Lake Forest College and NASA at KSC. Since the purpose of an expert system is to derive a hypothesis, its communication vocabulary is limited to features used by its knowledge base. The development of a comprehensive problem based medical record entry system which could handshake with an expert system while creating an electronic medical record at the same time was studied. IMR-E is a computer based patient record that serves as a front end to the expert system MEDAS. IMR-E is a graphically oriented comprehensive medical record. The programs major components are demonstrated.

Naeymi-Rad, Frank↗

NASA NTRS1991

The National Disaster Medical System

The Emergency Mobilization Preparedness Board developed plans for improved national preparedness in case of major catastrophic domestic disaster or the possibility of an overseas conventional conflict. Within the health and medical arena, the working group on health developed the concept and system design for the National Disaster Medical System (NDMS). A description of NDMS is presented including the purpose, key components, medical response, patient evacuation, definitive medical care, NDMS activation and operations, and summary and benefits.

Reutershan, Thomas P.↗

NASA NTRS1989

Living Well in Space: Clinical Care Challenge

This video describes the Health Maintenance Facility (HMF). The HMF provides inflight medical care including prevention, diagnosis, and care during transport if the patient must be evacuated. A comparison to medical services found in a large hospital is used to describe the HMF's subsystems.

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NASA NTRS1988

Answering the Space Medicine Challenge

The development of the Space Station Health Maintenance Facility (HMF) is featured. The HMF will provide necessary inflight medical care, including prevention, diagnosis, treatment, and care during transport if the patient must be evacuated from Space Station.

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NASA NTRS1993

Identifying and responding to customer needs at the Kennedy Space Center

The Patient Questionnaire Program at the Kennedy Space Center (KSC) has been in place for several years. It has helped to identify customer perceptions and needs. The questionnaire is presented and the survey results are discussed with respect to total quality management.

Ferguson, E. B.↗

NASA NTRS1993

OSHA Bloodborne Pathogens Standards Exposure Control Plan

The Hummer Associates Exposure Control Plan is designed to reduce significant occupational exposure to bloodborne pathogens and infectious materials for Hummer Associates health care personnel. Under universal precautions, all patients and all body fluids are considered potentially infectious for bloodborne pathogens. Medical personnel need not be at increased risk if universal precautions are correctly understood and followed. This program covers all employees who could reasonably anticipate contact with blood or other potentially infectious materials during the performance of their job responsibilities. Although HIV and hepatitis B are mentioned most often, this program applies to all bloodborne diseases. The two main components needed to implement this program are universal precautions and engineering/work practice controls. This program covers all employees who may have occupational exposure to blood or other potentially infectious materials. Other aspects of this program are discussed.

Luhrs, Caro Elise↗

NASA NTRS1993

Space research on organs and tissues

Studies in space on various physiological systems have and will continue to provide valuable information on how they adapt to reduced gravitational conditions, and how living in a 1 g (gravity) environment has guided their development. Muscle and bone are the most notable tissues that respond to unweighting caused by lack of gravity. The function of specific muscles and bones relates directly to mechanical loading, so that removal of 'normal forces' in space, or in bedridden patients, causes dramatic loss of tissue mass. The cardiovascular system is also markedly affected by reduced gravity. Adaptation includes decreased blood flow to the lower extremities, thus decreasing the heart output requirement. Return to 1 g is associated with a period of reconditioning due to the deconditioning that occurs in space. Changes in the cardiovascular system are also related to responses of the kidney and certain endocrine (hormone-producing) organs. Changes in respiratory function may also occur, suggesting an effect on the lungs, though this adaptation is poorly understood. The neurovestibular system, including the brain and organs of the inner ear, must adapt to the disorientation caused by lack of gravity. Preliminary findings have been reported for liver. Additionally, endocrine organs responsible for release of hormones such as insulin, growth hormone, glucocorticoids, and thyroid hormone may respond to spaceflight.

Tischler, Marc E.↗

NASA NTRS1993

Autogenic-feedback training: A potential treatment for post-flight orthostatic intolerance in aerospace crews

Postflight orthostatic intolerance was identified as a serious biomedical problem associated with long duration exposure to microgravity in space. High priority was given to the development of countermeasures for this disorder which are both effective and practical. A considerable body of clinical research demonstrated that people can be taught to increase their own blood pressure voluntarily and that this is an effective treatment for chronic orthostatic intolerance in paralyzed patients. The present pilot study was designed to examine the feasibility of adding training in control of blood pressure to an existing preflight training program designed to facilitate astronaut adaptation to microgravity. Using an operant conditioning procedure, Autogenic-Feedback Training (AFT), three men and two women participated in four to nine (15-30 training sessions). At the end of training, the average increase in systolic and diastolic pressure, as well as mean arterial pressures that the subjects made, ranged between 20 and 5O mmHg under both supine and 45 deg head-up tilt conditions. These findings suggest that AFT may be a useful alternative treatment or supplement to existing approaches for preventing postflight orthostatic intolerance. Further, the use of operant conditioning methods for training cardiovascular responses may contribute to the general understanding of the mechanisms of orthostatic intolerance.

Cowings, Patricia S.↗

NASA NTRS1994

Electrical stimulation in exercise training

Electrical stimulation has a long history of use in medicine dating back to 46 A.D. when the Roman physician Largus found the electrical discharge of torpedo fishes useful in the treatment of pain produced by headache and gout. A rival Greek physician, Dioscorides, discounted the value of the torpedo fish for headache relief but did recommend its use in the treatment of hemorrhoids. In 1745, the Leyden jar and various sized electrostatic generators were used to treat angina pectoris, epilepsy, hemiplegia, kidney stones, and sciatica. Benjamin Franklin used an electrical device to treat successfully a young woman suffering from convulsive fits. In the late 1800's battery powered hydroelectric baths were used to treat chronic inflammation of the uterus while electrified athletic supporters were advertised for the treatment of male problems. Fortunately, such an amusing early history of the simple beginnings of electrical stimulation did not prevent eventual development of a variety of useful therapeutic and rehabilitative applications of electrical stimulation. Over the centuries electrical stimulation has survived as a modality in the treatment of various medical disorders with its primary application being in the rehabilitation area. Recently, a surge of new interest in electrical stimulation has been kindled by the work of a Russian sport scientist who reported remarkable muscle strength and endurance improvements in elite athletes. Yakov Kots reported his research on electric stimulation and strength improvements in 1977 at a Canadian-Soviet Exchange Symposium held at Concordia University in Montreal. Since then an explosion of new studies has been seen in both sport science and in medicine. Based upon the reported works of Kots and the present surge of new investigations, one could be misled as to the origin of electrical stimulation as a technique to increase muscle strength. As a matter of fact, electric stimulation has been used as a technique to improve muscle strength for over a century. Bigelow reported in 1894, for example, the use of electrical stimulation on a young man for the purpose of increasing muscle strength. Employing a rapidly alternating sinusoidal induced current and a dynamometer for strength testing, Bigelow reported that the total lifting capacity of a patient increased from 4328 pounds to 4639 pounds after only 25 minutes of stimulation. In 1965, Massey et al. reported on the use of an Isotron electrical stimulator that emitted a high frequency current. Interestingly enough, the frequencies used by Massey et al. and the frequencies used by Bigelow in 1894 were in the same range of frequencies reported by Kots as being the most effective in strength development. It would seem the Russian secret of high frequency electrical stimulation for strength development, then, is not a modern development at all.

Kroll, Walter↗

NASA NTRS1991

Aircraft to Medicine

This video discusses how the technology of computer modeling can improve the design and durability of artificial joints for human joint replacement surgery. Also, ultrasound, originally used to detect structural flaws in aircraft, can also be used to quickly assess the severity of a burn patient's injuries, thus aiding the healing process.

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