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Biomedical subjects

R M Gardner

Publications and source records attributed to R M Gardner.

At least 109 records · Page 6Linked to original sources
PubMed1988

Physiological responses of obese subjects to external stimuli.

Physiological arousal was measured in 11 obese and 11 normal-weight subjects during presentation of emotive, food, and neutral stimuli. No differential arousal (heart rate, temperature, GSR, and EMG on frontalis muscle) between the groups was obtained for any of the three types of stimuli. Discrepancies between the present findings and earlier results are discussed.

Adolescent↗
PubMed1988

Physiological arousal of obese persons to food stimuli.

Physiological arousal was measured in 20 obese and 20 normal-weight subjects during presentation of imagery tasks with food- and nonfood-related stimuli and during presentation and eating of food. No differential arousal, as measured by skin conductance, was obtained between the groups for any of the stimuli. Presentation and eating of the food did produce significant arousal in subjects.

Adult↗
PubMed1988

Standardization of spirometry: a summary of recommendations from the American Thoracic Society. The 1987 update.

The spirometer is used to measure forced vital capacity in pulmonary, occupational, and general medicine. Results of spirometry affect decisions regarding patient treatment and disability compensation. Accurate spirometers are also required for epidemiologic studies. The recommendations of the American Thoracic Society cover equipment selection, validation, and quality control; maneuver performance recommendations; measurement procedures; and reference values and interpretation standardization.

Forced Expiratory Flow Rates↗
PubMed1988

Dynamics of invasive pressure monitoring systems: clinical and laboratory evaluation.

Seven pressure monitoring systems were evaluated in the clinical setting and in the laboratory to assess their adequacy for recording invasive blood pressures. We found that a large number of systems used in the clinical setting gave erroneous pressure results because of inadequate dynamic response. Results of testing similar systems in the clinical setting and under optimal laboratory conditions differed greatly. Four major findings were made: (1) Air bubbles in the monitoring systems near the transducer accounted for most of the variability of the dynamic characteristics of systems in the clinical setting; (2) simple catheter transducer system setups performed better, suggesting that simple "kits" be used; (3) membrane domes perform adequately if they are attached with care and according to the manufacturer's specifications; and (4) extension tubing was detrimental to the dynamic response of all systems, especially for pulmonary artery catheters. Fast-flush testing of pressure monitoring systems is needed to ensure the adequacy of dynamic response characteristics in the clinical setting. If the fast-flush characteristics are inadequate, physicians and nurses have the opportunity to troubleshoot the system and remove air bubbles and excessive tubing and to properly attach the transducer domes until optimal characteristics are obtained.

Blood Pressure Determination↗
PubMed1987

Interactions between estrogen and EGF in uterine growth and function.

The rat uterus contains specific, high-affinity EGF receptors which possess a tyrosine kinase activity. As demonstrated autoradiographically, these receptors are present in the epithelial, stromal and myometrial cells of the uterus. Estrogen treatment in vivo produces a 2-3-fold increase in EGF receptor levels in the immature rat, the immature mouse and the ovariectomized adult rat; furthermore, EGF receptor levels vary throughout the estrus cycle in concert with levels of occupied nuclear estrogen receptor. This estrogen-induced increase in EGF receptor is preceded by an increase in the level of EGF receptor mRNA as judged by Northern blot analysis. In general, there is a good correlation between estrogen-induced DNA synthesis and EGF receptor levels in the uterus, although in certain situations EGF receptor levels are elevated without a subsequent increase in DNA synthesis. These observations suggest that an increase in tissue EGF receptor levels is important in estrogen-induced uterine growth, but that this increase in receptor levels alone is not sufficient to stimulate DNA synthesis. In addition to its possible role in tissue growth, we have shown very recently that EGF causes contraction of myometrial smooth muscle in a completely in vitro organ bath system. The qualitative nature of this contractile response is distinct from that produced by other classical uterotonic agents. The physiological significance of this uterine response to EGF remains to be elucidated.

Animals↗
PubMed1987

Factors influencing production of 5(E)-19-nor-10-keto-vitamin D3 by rumen bacteria.

Mixed populations of rumen bacteria or Clostridium hastiforme (a rumen isolate) catalyzed the oxidation of vitamin D3 to 5(E)-19-nor-10-keto-vitamin D3. The reaction depended upon small amounts of O2 (less than 0.1% dissolved O2); when O2 was available, supernatant obtained from heat-killed mixed cultures also produced 5(E)-19-nor-10-keto-vitamin D3. Results obtained by ultrafiltration indicated that at least two heat-stable factors of bacterial origin were involved. Lower rates of the same oxidation were observed when O2 was introduced to solutions containing vitamins D3 and L-cysteine. Oxygen radicals are known to be produced in such solutions and the involvement of such radicals in the D3 oxidation is probable since production in cysteine solutions was inhibited by superoxide dismutase and catalase.

Aerobiosis↗
PubMed1987

Obesity and body image: an evaluation of sensory and non-sensory components.

Body image in 38 obese and normal weight subjects was measured using a video TV monitor. Tasks included a continuous task where subjects manipulated the size of their body image on a TV screen, and a discrete task, where they judged the accuracy of their TV image which was presented as either too heavy or too thin. Subjects viewed their images in both regular street clothes and with minimal clothing. Results from the continuous task revealed that obese subjects overestimated body size. All subjects were more accurate on trials in which the initial image was adjusted in the heavier direction. On the discrete task, a signal detection analysis revealed sensory sensitivity differences between obese and normal weight subjects. Obese subjects were better at detecting distortion caused by a too thin image, but were inferior in detecting a too heavy distortion. No significant differences were obtained in response criteria or between clothing conditions.

Adult↗
PubMed1987

Contractions of the isolated uterus stimulated by epidermal growth factor.

Epidermal growth factor (EGF) produces uterine contractions in tissues removed from immature and adult rats. EGF produces both an increase in resting tone and the development of rhythmic contractions, and this effect is abolished by treatment with antibodies against EGF. The ED50 for this response is observed at an EGF concentration of 3.5 nM. This in vitro effect of EGF requires treatment of the animals in vivo with estradiol for 24 h before removal of uterine tissue. This effect of estradiol does not appear to be due solely to an induction of tissue EGF receptors. These results demonstrate a new activity of EGF and suggest a previously unrecognized function for this peptide growth factor.

Animals↗
PubMed1987

Purification and characterization of an exo-beta-1,4-glucanase from Ruminococcus flavefaciens FD-1.

An exo-beta-1,4-glucanase (Exo A) from Ruminococcus flavefaciens FD-1 was purified to homogeneity and characterized. Enzyme activity was monitored during purification by using the substrate p-nitrophenyl-beta-D-cellobioside (NPC). Over 85% of the NPC activity was found to be extracellular once the filter paper was degraded (7 days). Culture supernatant was harvested, and the protein was concentrated by ultrafiltration. The retentate (greater than or equal to 300,000 Mr), containing most of the activity against NPC, was then fractionated with a TSK DEAE-5PW column. This yielded a sharp major peak of NPC enzyme activity, followed by a broader, less active area that appeared to contain at least six minor peaks of lower enzymatic activity. Further purification was achieved by chromatography with a hydroxylapatite column. Finally, gel filtration chromatography yielded a homogeneous enzyme (Exo A) as determined by silver stains of both sodium dodecyl sulfate- and nondenaturing electrophoresis gels. Substrate specificity experiments and the products of cellulose digestion indicate that the enzyme was an exo-beta-1,4-glucanase. Exo A required Ca2+ for maximal activity and had an apparent Km of 3.08 mM for NPC, with a Vmax of 0.298 mumol/min per mg of protein. The enzyme had an Mr of 230,000, as determined by gel filtration chromatography, and was a dimer of 118,000-Mr subunits. The N-terminal amino acid sequence of the enzyme is presented.

Amino Acid Sequence↗
PubMed1987

Turbine flowmeter vs. Fleisch pneumotachometer: a comparative study for exercise testing.

The purpose of this study was to investigate the characteristics of a newly developed turbine flowmeter (Alpha Technologies, model VMM-2) for use in an exercise testing system by comparing its measurement of expiratory flow (VE), O2 uptake (VO2), and CO2 output (VCO2) with the Fleisch pneumotachometer. An IBM PC/AT-based breath-by-breath system was developed, with turbine flowmeter and dual-Fleisch pneumotachometers connected in series. A normal subject was tested twice at rest, 100-W, and 175-W of exercise. Expired gas of 24-32 breaths was collected in a Douglas bag. VE was within 4% accuracy for both flowmeter systems. The Fleisch pneumotachometer system had 5% accuracy for VO2 and VCO2 at rest and exercise. The turbine flowmeter system had up to 20% error for VO2 and VCO2 at rest. Errors decreased as work load increased. Visual observations of the flow curves revealed the turbine signal always lagged the Fleisch signal at the beginning of inspiration or expiration. At the end of inspiration or expiration, the turbine signal continued after the Fleisch signal had returned to zero. The "lag-before-start" and "spin-after-stop" effects of the turbine flowmeter resulted in larger than acceptable error for the VO2 and VCO2 measurements at low flow rates.

Carbon Dioxide↗