Development of unique instrumentation using novel approaches is, in many instances, necessary to the success of biomedical research. Areas of emphasis within our group are summarized below.? ? A digital video, EEG imaging system with seizure detection for multiple small animals, being developed in collaboration with Drs. Michael Rogawski and Maciej Gasior NINDS, will detect and record seizures of small animals by monitoring their EEGs together with documenting the animals' accompanying behavior via video recording. The instrumentation consists of animal cages, swivel connectors connected to the head of each animal, EEG analog amplifiers, computer control with movie maker and graphics hardware, and software detection of spikes and seizure patterns. The system has been assembled and will visually display and record EEG data along with video of multiple small animals. The instrument has been tested on small animals and modifications have been made to the mechanical apparatus to allow for more flexible animal movement. The system will continue to be updated as the latest software changes become available. ? ? A laser flash photolysis apparatus was developed in collaboration with Dr. Fred Friedman, NCI, to measure the kinetics of carbon monoxide (CO) binding to cytochromes P450 in liver microsomes from rats treated with various drugs and carcinogens. Since numerous forms of P450 contribute to the overall reaction, a difference kinetic method was used to distinguish the kinetic behavior of individual P450s. This method entails analysis of the difference between the kinetic profiles in the absence and presence of a specific P450 effector, and successfully yielded kinetic parameters for individual P450s involved in drug and carcinogen metabolism. Specifically, various polycyclic hydrocarbons differentially accelerated CO binding to the P450 1A1, which metabolizes these carcinogens in a size- and shape-dependent manner. Wavelet analysis allows selection of critical short time scale regions where high frequency information predominates and provides information on the early events associated with the cytochrome P450 binding kinetics. ? ? In collaboration with Dr. Brian Brooks, CC, an eye movement system is being developed for use with patients who are unable to understand commands, such as infants, or patients with below-average verbalization or language barriers. Stimuli, such as sound, light, or motion of objects cause eye movements toward the stimuli. The unit has been installed, tested and used on patients in an ophthalmic testing laboratory.? ? In collaboration with Dr. Steven Stanhope and Shih-Chiao Tseng, CC, a time reaction reflex movement system is being developed to test a person's reaction time in attempting to follow a laser beam directed at the floor. Signals generated in a computer system change the position of the light and indicate when a particular light stimulus is activated and deactivated. The computer correlates signals from force plates in the floor with foot placement. The system has been completed and is ready for initial patient testing. ? ? In collaboration with Dr. Richard Hendler, NHLBI, a modified version of a high speed optical multichannel spectrometer, developed previously, has been enhanced in terms of temporal and signal amplitude resolution. The kinetics of the bacteriorhodopsin photocycle, initiated with a synchronized laser pulse (532nm, 7ns), is being studied using an optical system that follows the spectral changes associated with the transient intermediates of the photocycle. Complete spectra from approximately 400nm to 700nm are collected with less than 10 microsecond resolution, permitting extraction, though single value decomposition analysis, of the role of the intermediates. To adapt to the next phase of this project, which entails collecting infrared data, a collaboration has been established with the National Institute of Standards and Technology. The optical system has been realigned to incorporate both the high-speed multichannel analyzer and the infrared spectrometer.? ? In collaboration with Dr. Janine Smith, NEI, an ocular imaging system for measuring dry eye severity is being developed. The method uses the Oxford Scheme for grading ocular staining in dry eyes using various dyes. The software for ocular image analysis is complete and will be tested in the clinic in conjuction with a slit biomicroscope. The image analysis uses a support vector machine (SVM) algorithm from statistical learning theory. An ocular instrument will be developed for improving image capture, image enhancement, and the correction of imaging defects. It is intended that the system will enhance image quality by minimizing the potential effects of eye movement, glare, vignetting, lens distortion, noise, and non-uniform eye lighting. System and monitor calibration techniques for color management and white balance will be developed. Instillation and timing of dye administration will be controlled to account for time dilution of dye staining. A database will be developed for storing patient information and history, and to save patient images. Both the instrument and software will be initiated using a semi-automated system with the goal of future development as a fully automatic system.
