Biomedical subjects

R D Jones

Publications and source records attributed to R D Jones.

238 records · Page 14Linked to original sources

PubMedDate not supplied

Impairment and recovery profiles of sensory-motor function following stroke: single-case graphical analysis techniques.

Graphical analysis procedures have been developed to improve interpretation of sensory-motor tests from individual subjects following acute brain damage. The procedures have been applied to 11 unilateral stroke patients assessed serially over 12 months on a computerized quantitative sensory-motor test battery of which grip strength, arm speed, and tracking have been chosen for illustrative purposes. The results indicate that four graphs are necessary to fully demonstrate neurologic impairment and recovery of each sensory-motor function, although fewer graphs would be satisfactory in some applications. Such analyses have proven valuable in the display of serial performance of individual patients but demonstration of impairment and recovery is much more difficult than for group analyses.

Activities of Daily Living↗

PubMedDate not supplied

Comparative pharmacokinetics of propofol in Chinese adults and children.

The pharmacokinetics of propofol were studied in 14 healthy young male Chinese adults, aged 18-38 years, undergoing minor orthopedic surgery. All patients who received a single bolus dose of propofol 2.5 mg/kg were paralyzed with atracurium and mechanically ventilated. Anesthesia was maintained with 67% nitrous oxide plus 1-2% isoflurane in oxygen with alfentanil 5 micrograms/kg intravenously as a bolus injection. Blood concentrations of propofol over the subsequent 24 hours were measured using high pressure liquid chromatography with fluorimetric detection. Data were consistently described by a three compartment model but analysis revealed two significantly different blood propofol concentration-time profiles (p less than 0.05). Five patients, designated "fast" metabolizers, demonstrated a mean elimination half-life which was shorter than that described in Chinese children, while their total body clearance was similar. Nine other patients, designated "slow" metabolizers, had a longer mean elimination half-life and slower total body clearance than those in elderly Caucasian patients. This may be suggestive of propofol metabolism at some extra-hepatic site in some patients, while other patients demonstrate marked lipophilicitic constraint of the drug by the deep compartment.

Adolescent↗

PubMedDate not supplied

A miniature segment-length strain gauge arch for the assessment of myocardial function.

A miniature myocardial segment-length strain gauge arch utilizing solid-state strain gauge elements is described. The arch weighs 0.25 g, has a frequency response flat to 30 Hz, requires simple circuitry, and is stable in situ for periods exceeding 6 hours. Its miniaturization and ease of insertion offer distinct advantages over similar devices previously described. Miniature arches have been applied simultaneously to multiple sites to assess left ventricular function in dogs. The response of these arches to a variety of interventions indicates that this device may be used to follow localized segment-length and velocity changes. The study also clearly demonstrates that the orientation of strain gauge arches with respect to muscle fiber direction in the ventricular wall qualitatively and quantitatively affects the recorded segment-length alterations.

Animals↗

PubMedDate not supplied

Biologically based validation of PC electrophysiology data collection systems utilizing the Good Automated Laboratory Practices.

Since there was a scientific need to conduct electrophysiology measurements to detect possible ocular (electroretinography, ERG), central neurotoxic (quantitative electroencephalography, qEEG), and cardiac (electrocardiography, ECG) effects in animals used in certain regulatory studies, the acquisition of suitable automated PC software systems were required. This article describes the process by which these systems were validated to ensure that they met the scientific requirements, while also addressing the principles of Good Automated Laboratory Practices (GALP). After a thorough search of existing commercial packages, a plan was developed specific for each PC-based collection system selected for evaluation. The common elements of each plan included consideration of both scientific and GALP elements, such as necessary biological response variables, raw data acquisition and identification, acceptance criteria, security, protection, storage media, data integrity, audit requirements and standard operating procedures. The authors' approach to validation for each electrophysiology system was to determine scientific needs for accuracy, precision, and detection limit of biological effects concurrent with GALP requirements. The selected software systems were employed in separate scientific GLP studies conducted in dogs, rats, and mini-pigs to demonstrate the ability to detect cholinesterase effects due to multiple infusions of physostigmine, based on parallel measurement of cholinesterase biomarkers. Since the systems were designed for human usage, certain adaptations were necessary. A critical assumption to be tested was the ability of the system's algorithms to adequately capture and assimilate the data in an accurate fashion. Concomitantly, the related GALP needs, such as data integrity, security, CD-ROM archive, and personnel training requirements were evaluated, implemented, and defined to accommodate the application and process needs. The biological approach to validation of these PC-based electrophysiology systems met the necessary scientific acceptance criteria as well as compliance requirements in order to be used in regulatory studies.

Algorithms↗