Engineering topics

Giblin, Frank J.

Publications and source records attributed to Giblin, Frank J..

3 records

NASA NTRS2005

Protection against UV and X-ray cataracts using dynamic light scattering

Static and dynamic light scattering (SLS and DLS) analysis was used to investigate the aggregation of lens proteins in a hyperbaric oxygen (HBO)/guinea pig in vivo model for nuclear cataract. Nuclear cataract, an opacity which occurs in the center of the lens, is a major type of human maturity-onset cataract for which the cause is not well-understood. HBO is commonly used in major hospitals for treating complications such as poor wound healing due to impaired blood circulation. It is known that treatment of human patients with HBO for extended periods of time can produce nuclear cataract. Guinea pigs, initially 18 months old, were treated with HBO (2.5 atm of 100% O2 for 2.5 hr) 3x per week for 7 months to increase tie level of lens nuclear light scattering. Age-matched animals were used for controls. The eyes of the animals were analyzed in vivo using an integrated static and DLS fiber optic probe in collaboration with the NASA group. DLS in vivo was used to measure the size of lens proteins at 50 different locations across the optical axis of the guinea pig lens.

Giblin, Frank J.↗

NASA NTRS2002

Non-Invasive, Quantitative, and Remote Detection of Early Radiation Cataracts for Applications in Bio-Astronautics and Bio-Informatics

Human exploration of Mars may be a possibility in the next twenty years. Maintaining good vision is an essential aspect of achieving a successful mission. Continuous radiation exposure is a risk factor for radiation-induced cataracts in astronauts. A compact device based on the technique of dynamic light scattering (DLS) is designed for monitoring an astronaut's ocular health during long-duration space travel. Preliminary data on the simulated effects of ionizing radiation exposure to the ocular tissues of nonhuman animals and results on the sensitivity of DLS over established clinical procedures in investigating cataracts are presented. This capability of early diagnosis, unmatched by any other clinical technique in use today, may enable prompt initiation of preventive/curative therapy. An internet web based system integrating photon correlation data and controlling the hardware to monitor cataract development in vivo at a remote site in real time (teleophthalmology) is currently being developed. Cataract studies on-board the International Space Station (ISS) will be helpful in designing better protective radiation shields for future space vehicles and space suits.

Ansari, Rafat R.↗

NASA NTRS2000

Applications in Bioastronautics and Bioinformatics: Early Radiation Cataracts Detected by Noninvasive, Quantitative, and Remote Means

Human exploration of Mars is a key goal in NASA's exploration planning in the next 20 years. Maintaining crew health and good vision is certainly an important aspect of achieving a successful mission. Continuous radiation exposure is a risk factor for radiation-induced cataracts in astronauts because radiation exposure in space travel has the potential of accelerating the aging process (ref. 1). A patented compact device (ref. 2) based on the technique of dynamic light scattering (DLS) was designed for monitoring an astronaut's ocular health during long-duration space travel. This capability of early diagnosis, unmatched by any other clinical technique in use today, may enable prompt initiation of preventive/curative therapy. An Internet web-based system integrating photon correlation data and controlling the hardware to monitor cataract development in vivo at a remote site in real time (teleophthalmology) is currently being developed. The new technology detects cataracts very early (at the molecular level). Cataract studies onboard the International Space Station will be helpful in quantifying any adverse effect of radiation to ocular health. The normal lens in a human eye, situated behind the cornea, is a transparent tissue. It contains 35 wt % protein and 65 wt % water. Aging, disease (e.g., diabetes), smoking, dehydration, malnutrition, and exposure to ultraviolet light and ionizing radiation can cause agglomeration of the lens proteins. Protein aggregation can take place anywhere in the lens, causing lens opacity. The aggregation and opacification could produce nuclear (central portion of the lens) or cortical (peripheral) cataracts. Nuclear and posterior subcapsular (the membrane's capsule surrounds the whole lens) cataracts, being on the visual optical axis of the eye, cause visual impairment that can finally lead to blindness. The lens proteins, in their native state, are small in size. As a cataract develops, this size grows from a few nanometers (transparent) to several micrometers (cloudy). Ansari and Datiles have shown that DLS can detect cataracts at least two to three orders of magnitude earlier noninvasively and quantitatively than the best imaging (Scheimpflug) techniques in clinical use today (ref. 3).

Ansari, Rafat R.↗