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Biomedical subjects

R P Patterson

Publications and source records attributed to R P Patterson.

36 records · Page 2Linked to original sources
PubMed1984

Heart rate, rate-pressure product, and oxygen uptake during four sexual activities.

Heart rate, rate-pressure product, and VO2 were measured in ten healthy men during four specified sexual activities: coitus with husband on top, coitus with wife on top, noncoital stimulation of husband by wife, and self-stimulation by husband. Foreplay generated slight, but statistically significant, increases above resting baseline in cardiac and metabolic variables. From stimulation through orgasm, average effort was modest for relatively short spans. Maximum exercise values occurred during the brief spans of orgasm, then returned quickly to near baseline levels. The two noncoital activities required lower expenditures than the two coital positions, with man-on-top coitus rating the highest. Large variations among subjects and among activities discourage use of a general equivalent activity for comparison, such as "two flights of stairs," to represent "sexual activity."

Adult↗
PubMed1981

The response of the oxygen pulse during a stress test in patients with coronary artery disease.

The pattern of change of the O2 uptake . beat-1 versus the difference between the measured and predicted MET level varied considerably during a progressive exercise stress test among patients with coronary artery disease and normals. For normal subjects under work load changes from 2 to 10 MET (1 MET = resting VO2), the O2 . beat-1 approximately doubled; whereas for some patients, the value fell near the end of the stress rest to a level near that at the beginning. This parameter is one measure of the efficiency of the cardiovascular system to respond to exercise and appeared to correlate with the physiological condition of the patient.

Coronary Artery Bypass↗
PubMed1981

Energy cost of ambulation with crutches.

Energy consumption data were obtained on 8 normal subjects ambulating with underarm crutches, using a 3-point gait at 30, 40, 50, 60, 70, and 80 meters per minute (m.min-1) on level terrain, and 40, 60m.min-1 on a 5% grade, and climbing 19-cm stairs at 16 and 24 steps/minute. The subjects ambulated without crutches at 30, 50, 70m.min-1 on the level, 60m.min-1 on a 5% grade, and stairs at 16 and 24 steps/minute. Oxygen consumption (VO2) and ventilation data were obtained from a portable device. Respiratory quotients were determined from samples of expired gas. Maximal upper extremity(bicycle ergometer) and lower extremity (treadmill) stress tests were determined. The energy cost (oxygen consumption) VO2.wt-1 (ml.min-1.kg-1) of ambulating with underarm crutches compared to normal walking was approximately twice as great. The heart rate (HR) and VO2 for any given rate of vertical rise tested was less with crutch stair climbing than with crutch walking. There was no difference in VO2 or HR when ambulating with underarm compared to forearm (Lofstrand) crutches.

Adult↗
PubMed1980

Pressure and temperature patterns under the ischial tuberosities.

A study was conducted to investigate the pressure relief patterns under the ischial tuberosities in group of 12 paraplegic subjects. A small electrical pressure transducer was taped over each ischial tuberosity, and each subject had a thermistor taped near one tuberosity. The subjects were instrumented in the morning and allowed to go about their normal activities for the day sitting on a 4-inch foam cushion. The subjects sat at pressures greater than 150, greater than 90, and greater than 30 mmHg for 17.6 percent, 53.5 percent, and 91.8 percent of the time, respectively. The subjects sat on the average for 10.1 min without doing a pushup with a duration greater than 1 sec and sat on the average for 29.6 min without doing a pushup with a duration greater than 5 sec. Two of the subjects sat for periods greater than 60 min for greater than 75 percent of the time (ignoring pushups less than 5 sec) and greater than 65 percent of the time ignoring pushups less than 1 sec. The average time between pushups was within the generally accepted limits to prevent ulcers--10-30 minutes. A few of the subjects had occasional long periods of uninterrupted pressure greater than what is thought to be required to produce ulcers--and did not develop them.

Adult↗
PubMed1979

Growth and Specific Nodule Activity of Soybean during Application and Recovery of a Leaf Moisture Stress.

Soybean plants growing at day/night temperatures of 30/18, 26/18, and 22/18 C were subjected to a single drying and recovery cycle during an 18- to 19-day period in the early to midpod development stage. Leaf total electrochemical water potential was reduced to about -24 bars during the 4-day drying cycle at all temperatures, but recovered to control levels upon rewatering. The changes in dry matter accumulation in whole plants and plant parts, specific activity of nodules as measured by acetylene reduction, and levels of adenosine phosphates in nodules were measured periodically during stress and recovery.Vegetative and reproductive growth were about equally suppressed by the leaf moisture stress. Both rate of appearance and number of pods were reduced. However, a similar average weight per pod for both stressed and control plants at the conclusion of the recovery period suggests that individual pod development is not irreversibly affected by a single stress cycle and that yield potential is restricted by a decrease in number of pods or seed. Dry matter accumulation in plants and pods was unaffected by temperature.Specific nodule activity and energy charge of nodules declined concurrently with leaf moisture potential. Recovery of specific nodule activity following rewatering lagged behind recovery of leaf moisture potential, but energy charge of nodules recovered as rapidly as leaf moisture potential upon rewatering. Thus, the delayed recovery of specific nodule activity does not appear to be related to recovery of energy charge of the nodules.

Journal Article↗
PubMed1978

The electrical characteristics of some commercial ECG electrodes.

The impedance and offset potential of six disposable and two non-disposable electrodes were measured on 80 subjects. A total of 160 measurements were made on skin prepared by wiping with alcohol or acetone. For 640 measurements the skin was prepared by lightly sanding. The sanding of the skin reduced the impedance by a factor of approximately 50 for males and 100 for females. The offset potential for sanded skin was reduced by approximately 2. The performance of the disposable electrodes showed no great practical difference when applied on sanded skin. The median impedance ranged from 1500 to 3250 ohms. The median offset potential ranged from 0.5 to 4 mV. It was shown that a small DC current of 100 nA applied to stainless steel electrodes could cause a polarization voltage of approximately 0.5 volts to appear in 25 min.

Disposable Equipment↗
PubMedDate not supplied

Dinitrogen fixation in soybean in response to leaf water stress and seed growth rate.

Late season declines in N2 fixation by soybeans [Glycine max (L.) Merr.] frequently are observed under field conditions but do not always occur under glasshouse and growth chamber culture where water stress is avoided and photoperiod is manipulated to alter rate of seed growth. To evaluate the effects of water stress and photoperiod during reproductive growth declines in N2-fixation, nodulated 'Ransom' soybeans dependent entirely on N2-fixation and growing under controlled environment conditions were divided into two groups at the beginning seed (R5) stage. At R5, photoperiod was utilized to experimentally alter the rate of seed growth as a sink for photosynthate and N by imposing a short-day photoperiod (SD) on half of the plants and a long-day photoperiod (LD) on the other half. Within each photoperiod treatment, half of the plants were subjected to a single episode of leaf water stress between -1.2 and -1.8 MPa at the full seed (R6) stage, and half served as nonstressed controls. Plants were sampled at 1- to 5-day intervals between R5 and full maturity (R8) stages and analyzed for N and total nonstructural carbohydrates (TNC). The rate of N accumulation from N2-fixation declined during reproductive growth for the stressed plants but not for the nonstressed plants. Thus, a water stress can actuate a late season decline in N2-fixation. When rate of seed growth was slowed under LD, N composition in leaves remained higher following water stress than when a faster rate of seed growth was promoted under SD. Dinitrogen-fixation activity and dry matter production recovered after rewatering for stressed plants under LD but not under SD. Concentration of TNC in leaflets was greater under LD for both stressed and nonstressed plants. Thus, concentration of TNC in leaflets does not appear to be as important in recovery from water stress as concentration of N.

Biomass↗