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Biomedical subjects

R M Gardner

Publications and source records attributed to R M Gardner.

At least 127 records · Page 7Linked to original sources
PubMed1987

Measurement of anaerobic threshold in chronic airflow obstruction.

We compared determinations of anaerobic threshold (AT) made from measurements of arterial lactate concentration with AT determined from ventilatory response measurements of subjects with chronic airflow obstruction (CAO). Six untrained subjects with CAO performed incremental maximal cycle ergometer tests. Ventilation (VE); O2 uptake (VO2), CO2 output (VCO2); end-tidal CO2 fraction (FETCO2); and end-tidal O2 fraction (FETO2) were measured breath by breath. Arterial lactate concentration was sampled at rest and every 30 s during exercise from an indwelling arterial catheter. For three subjects with more severe airflow obstruction, plots of VE/VO2 and FETO2 failed to detect AT. In contrast, a systematic increase of the respiratory gas exchange ratio across the lung (R) accompanied increasing arterial lactate concentrations in all 6 subjects. We conclude that progressive increases of VE/VO2 and FETO2 cannot be relied upon for the measurement of AT in patients with severe CAO. Progressive increases of R unaccompanied by decreasing FETCO2 detect AT in CAO.

Aged↗
PubMed1987

Bringing HELP to the clinical laboratory--use of an expert system to provide automatic interpretation of laboratory data.

In domains where the types of data which are to be interpreted are relatively constrained (as in the case of specific laboratory test results), our modular data-driven approach can be very productive and well received by the clinical recipient of the data. The computer rarely surpasses the knowledge of an experts result from lack of communication, imperfect memory, oversight or multiple decision-makers caring for the same patient. In such cases, most of the alerts are immediately recognized as valid, so the need for elaborate explanations is not a high priority. On the other hand, a non-specialist is alerted to the need for additional investigation, tests or collaborative support, by the fact that a reminder or diagnosis that s/he had not previously considered, appears. In other words, for the expert, a data-driven system provides unceasing oversight in high-volume low-yielded situations where a small number of mistakes may uncommonly occur for reasons which are not related to the lack of knowledge of the provider. For the non-specialist the system suggests that the patient may have problems in a domain for which the physician needs additional support. In the present state of the art, we do not think that total reliance on the computer-contained knowledge is the ultimate source of this additional support; providing the awareness of the need may be the most important contribution. Once you know that you need help, it is usually obtainable. In a discussion about how computer systems have failed, Friedman and Gustafson made the following observation.(ABSTRACT TRUNCATED AT 250 WORDS)

Decision Making, Computer-Assisted↗
PubMed1986

Optimizing the electrocardiogram and pressure monitoring.

Monitoring the electrocardiogram and directly measuring BP provide current and important data for intraoperative and ICU patient management. However, these physiologic measurements are not infallible; their accuracy is largely dependent on the careful set-up and use of the measuring instruments. This report integrates practical clinical and engineering information to provide a basis for optimizing ECG and pressure monitoring in the clinical setting.

Blood Pressure Determination↗
PubMed1986

Classical conditioning of pupillary constriction.

Previous attempts to condition classically the pupillary response have resulted in mixed outcome. Studies using light as the UCS have generally been unsuccessful while those studies using shock as the UCS have been more successful. In the present study six subjects were visually presented 15 CVC trigrams while their pupil sizes were monitored. Five of the CVCs had been previously presented, five had been previously presented while paired with shock, and five had not been previously presented. Analysis indicated that more pupillary constriction occurred to the five CVCs paired with shock than those presented without shock or those not previously presented. The resulting classically conditioned pupillary constriction is discussed in terms of the development of meaning through classical conditioning.

Cognition↗
PubMed1986

Signal-detection analysis of recognition memory of obese subjects.

Obese and normal-weight subjects were run on a series of recognition-memory tasks with low and high meaningful CVC trigrams. Subjects received feedback or no feedback regarding the appropriateness of their answers during testing for recognition memory. A signal-detection analysis was used to examine a relatively pure index of memory (d') as compared to response-bias factors [Ln (beta)]. No significant main effect on memory of obese and control subjects was noted although a significant interaction indicated that obese subjects' memory increases over trials in a differential fashion from normal-weight individuals with poorer performance among the obese after 3 trials. Feedback facilitated memory for both groups. Analysis of response criteria [Ln (beta)] showed no significant difference between groups. Highly meaningful trigrams had a significantly lower response criterion than low meaningful trigrams and there was a significant interaction of meaningfulness by trials. An interaction of feedback by meaningfulness was also present. Advantages of using a signal-detection analysis in memory studies comparing obese and normal weight subjects are discussed. Ramifications of the present data for the internality/externality hypothesis of obesity are also discussed.

Adolescent↗
PubMed1985

Development of a computerized infectious disease monitor (CIDM).

At the LDS Hospital in Salt Lake City, an interface was developed between the microbiology laboratory computer system and the HELP integrated central hospital computer system. The HELP system includes medical information from most clinical care support areas. The microbiology data are translated from the laboratory computer file structure to a hierarchical data structure on the HELP system. A knowledge base was created with the help of infectious disease experts, and became part of a Computerized Infectious Disease Monitoring system (CIDM). The knowledge base is automatically activated when specific microbiology data are entered into a patient's computer file (data driven), thus decisions are made automatically with no additional effort required of medical personnel. The CIDM was designed to inform infectious disease personnel when a patient has one of the following conditions: a hospital-acquired infection, an infection at a normally sterile body site, an infection due to a bacteria with an unusual antibiotic sensitivity pattern, an infection for which the patient is not receiving an antibiotic to which the offending bacteria is sensitive, an infection that could be treated with a less expensive antibiotic, an infection which is required by law to be reported to state and national health authorities, and those patients receiving prophylactic antibiotics longer than is medically indicated. All of the microbiology data are now extensively reviewed by nurses and physicians from terminals at nursing stations or intensive care units. The CIDM is currently being used for hospital-acquired infection surveillance at LDS Hospital.

Anti-Bacterial Agents↗
PubMed1985

Computerized data management and decision making in critical care.

Computers are being increasingly employed in all levels of society. Computer applications in clinical medicine have lagged behind administrative and billing functions. However, computers are now finding an increasingly useful place in critical care medicine. The complexity of the patients' conditions and the large amount of data generated by critically ill patients provide an ideal area of application for computers. The computer can assist in collecting data, calculating derived parameters, speeding data communications, record keeping, report generation, and decision making. This article has discussed and illustrated how the computer can aid in the care of the critically ill.

Critical Care↗
PubMed1985

Effects of mepacrine on uterine contractile responses.

Mepacrine is a potent inhibitor of uterine contractile responses in vitro. Pretreatment of isolated rat uterine horns with mepacrine (1.3 X 10(-4)M) for periods of time ranging from 15 s to 5 min prior to the addition of carbachol (1.0 X 10(-4)M) showed that mepacrine could significantly reduce carbachol-induced uterine contractile responses within 15 s of exposure. The maximal inhibitory effects of mepacrine on uterine contractile responses were observed within 2 min of mepacrine treatment. A dose-response study related to the effect of increasing concentrations of mepacrine (7.5 X 10(-6) to 1.3 X 10(-4)M) on carbachol-induced (1 X 10(-4)M) uterine contractions revealed that a dose of 3.1 X 10(-5)M mepacrine reduced the carbachol-induced contraction by 50%. A dose of 7.8 X 10(-5)M mepacrine produced the maximal inhibitory effect on the carbachol-induced uterine contractions. Two doses of mepacrine (3.1 X 10(-5) and 1.3 X 10(-4)M) significantly reduced maximal contractile responses and shifted contractile dose-response curves of carbachol, oxytocin, prostaglandin F2 alpha, and BaCl2 to the right. Based on the nonselective inhibition by mepacrine of contractile responses induced by different uterotonic agents, these results suggest that mepacrine cannot be used to characterize the role of phospholipase in regulating the actions of hormones in uterine tissue.

Animals↗
PubMed1985

Frequency of wedge pressure errors in the ICU.

Using 94 flow-directed pulmonary artery catheters in 53 ICU patients, we obtained prospectively 282 pulmonary artery wedge pressure (WP) measurements from 286 attempts. After catheter manipulation, 96% of these WP measurements were ultimately free of technical problems, and 84% were confirmed by aspiration of pulmonary capillary blood from the wedge position. The 95% confidence interval for repeated measurements of WP in stable ICU patients was 4 mm Hg. The WP measurement error was defined as the difference between unconfirmed and confirmed WP pairs obtained from stable patients. The probability of encountering a WP measurement error of at least 4 mm Hg was 33% for the 93 WP measurements with technical problems, 5% for the 189 WP measurements without technical problems, and 14% for the entire set of 286 WP measurement attempts. Quality control procedures, including dynamic response testing, easily identified most errors.

Adolescent↗
PubMed1985

Effects of experimentally-induced diabetes on oestradiol-stimulated changes in the ultrastructure of the rat endometrium.

Alterations in endometrial cell morphology following oestradiol treatment of ovariectomized animals were examined in euglycaemic and streptozotocin-induced diabetic rats. Endometrial morphology was examined 18, 24, 36 and 48 h after oestradiol administration. Nuclei of endometrial cells from saline injected euglycaemic and diabetic rats exhibited pleomorphic nuclei with areas of heterochromatin dispersed throughout the nucleus. Nucleoli were homogeneous in appearance and endometrial cells showed no mitotic chromosome function or cell division. The cytoplasm of euglycaemic and diabetic cells contained few mitochondria. The mitochondria that were present contained a uniformly dense matrix and cristae that extended across the mitochondria. The formation of round to oval shaped nuclei with diffuse euchromatin was observed at 18, 24 and 36 h following oestradiol administration in euglycaemic animals. Alterations in nuclear morphology and the formation of euchromatin were absent or reduced at the same time intervals examined in diabetic animals. Nucleoli in oestradiol-treated euglycaemic animals at 18, 24 and 36 h post-injections became very prominent and displayed easily visible granules and fibrillar material. Comparable changes in nucleolar morphology in oestradiol-treated diabetic rats were absent. The development of oval to round mitochondria containing short cristae and an electron-lucent matrix became apparent at 18 h post-injection of oestradiol in euglycaemic control animals. Alterations in mitochondrial morphology did not appear in endometrial cells of oestradiol-treated diabetic animals at any of the time points examined. At 24 and 36 h post-injection of oestradiol in euglycaemic animals, mitotic figures were observed in mitochondrial cells. Cell division and mitotic figures were not observed in oestradiol-treated diabetic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗