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Biomedical subjects

B T Engel

Publications and source records attributed to B T Engel.

At least 73 records · Page 4Linked to original sources
PubMed1985

A longitudinal study of tolerance to cold stress among C57BL/6J mice.

C57BL/6J male mice of different ages were movement-restricted and exposed to 10 degrees C for 3-hr periods every other week while colonic temperature was measured. A longitudinal trend in cold tolerance related to age and to initial colonic temperature was demonstrated. Adaptative thermoregulatory changes during cold exposure occurred during the first two tests. These were similar for all age groups except 30-month-old mice. There was no adaptation of colonic temperature during cold exposure among aged mice with repeated testing; however, their baseline colonic temperatures prior to testing increased after the first two tests. This finding suggests that old animals adjust to repeated cold stress differently than do younger mice. Specifically, younger animals are capable of adjusting their thermoregulatory response during cold stress with no change in baseline (pre-stress) temperature. Old animals do not modify the responses emitted during the stress; however, they do adapt by raising their baseline temperatures. Repeated cold exposure started later in life increased mortality among old animals but did not affect maximum lifespan.

Adaptation, Physiological↗
PubMed1985

Biofeedback treatment of fecal incontinence in geriatric patients.

Eighteen fecally incontinent geriatric patients were first treated for constipation as a possible cause of incontinence, and the 13 who remained incontinent were provided sphincter biofeedback training. Half the patients were instructed to perform 50 sphincter exercises per day for a four-week period prior to the start of biofeedback training to determine whether such exercises would improve bowel control in the absence of biofeedback training. Sphincter exercises alone did not produce clinical improvements and did not significantly increase the strength of sphincter contractions. Biofeedback training did significantly augment sphincter strength and was associated with greater than 75 per cent decreases in incontinence for 10 (77 per cent) of the patients. Improvements were maintained in 60 per cent at six months and in 42 per cent at one year. Thus biofeedback training appears to be of specific value in the treatment of fecal incontinence in geriatric patients.

Aged↗
PubMed1985

Central control of cardiovascular adjustments to exercise.

Voluntary heart rate (HR) control during moderate exercise on a bicycle ergometer was studied in 10 healthy physically conditioned men (5 experimental and 5 control). The results showed that subjects could learn to attenuate the tachycardia of exercise while exercising at a steady work level of 60-70% of maximum HR. Experimental subjects who saw beat-to-beat displays of HR and were instructed to slow HR showed 22% less increase in HR than did control subjects who exercised without HR displays or instruction to slow HR (42.6 vs. 54.6 beats/min). When the control subjects were given feedback in additional sessions, they also decreased HR significantly by 9% (54.6 vs. 49.9 beats/min). Analyses of concomitant respiratory and metabolic data showed that HR attenuation was accompanied by decreased O2 consumption (P less than 0.06) and pulmonary ventilation (P less than 0.01). Rate pressure product also fell, indicating a decrease in myocardial O2 consumption. Comparisons among pre- and postsubmaximal and cardiovascular pulmonary and humoral responses during maximal test sessions suggested that the improvement in cardiopulmonary function during feedback training occurred with no sacrifice to working muscle requirements because blood lactate concentrations were similar. The attenuation of the HR response obtained in the present study indicates that feedback training in physically conditioned subjects can influence cardiovascular responses even under conditions of heavy local demands imposed by working muscles.

Adult↗
PubMed1985

Urinary incontinence in the elderly. Bladder-sphincter biofeedback and toileting skills training.

Behavioral treatment of urinary incontinence was given to 39 elderly outpatients; 19 had stress incontinence, 12 detrusor motor instability, and 8 urge incontinence without instability. Biofeedback involving the bladder and sphincter was used to teach selective control of sphincter muscles or voluntary inhibition of detrusor contractions. Traditional behavioral methods used included habit training to gradually increase the voiding interval and relaxation training to cope with the urge to void. After an average 3.5 training sessions, patients with stress incontinence reduced the frequency of incontinent episodes an average of 82% (range, 55% to 100%). Patients with detrusor motor instability showed an average 85% improvement (range, 39% to 100%), and patients with urge incontinence reduced incontinence an average of 94% (range, 83% to 100%). Furthermore, 13 of the patients achieved total continence, and 19 had fewer than one accident per week after treatment.

Abdomen↗
PubMed1984

Age-related decline in cold tolerance can be retarded by brain stimulation.

The sharp decline in capacity of old C57BL/6J male mice to maintain body temperature during 3-hr cold exposure can be delayed and even partly restored after 15, 30-min, daily sessions of hypothalamic self-stimulation. In control experiments it was demonstrated that electrical stimulation of "rewarding" areas of hypothalamus itself is sufficient for improvement of the age-related deterioration of thermoregulatory ability.

Acclimatization↗
PubMed1984

An improved cold stress test for aging mice.

Tolerance to cold stress is a simple and reliable test which can be used longitudinally to study age-related differences or changes in thermoregulation of C57BL/6J mice. Neither prior food deprivation nor permanently inserted thermoprobes are necessary conditions for eliciting reliable age differences. However, restraint during the test is important and does elicit reliable age differences.

Aging↗
PubMed1984

Operant conditioning and the modulation of cardiovascular function.

Operant learning appears to be one of the primary mechanisms underlying what cardiovascular and pulmonary physiologists have called adaptation, habituation, and central command. In general, studies that have attempted to use operant conditioning alone to create experimental models of behaviorally induced disease have been unsuccessful because the cardiovascular responses adapted or habituated over time. Thus, these studies have provided implicit demonstrations of the roles played by CNS and conditioning processes in achieving and preserving homeostasis. During the past few years those interested in behavioral contributions to cardiovascular pathology have therefore begun to look at interactions between behavior and other variables that might predispose organisms towards pathology (e.g. genetic background; excessive sodium intake). Perhaps even more promising has been the growth in the number of technically competent, well-controlled studies designed to investigate: (a) broad scientific questions of how behaviorally important processes such as learning and reinforcement interact with physiologically important variables such as blood flow redistribution and cardio-pulmonary integration; and (b) the role of behavioral variables in CNS control of the circulation. Based upon our survey of the recent literature, we believe that the time is ripe for those interested in cardiovascular neurobiology increasingly to include behavioral variables in their studies, because the raison d'etre of the CNS is to optimize the organism's ability to interact with its environment. Only when these organismic-environmental interactions are studied both behaviorally and physiologically, in a broad biological context, will it be possible to develop rational models of neuro-circulatory regulation.

Animals↗
PubMed1983

Behavioral treatment of high blood pressure: III. Follow-up results and treatment recommendations.

This article is the third in a series of studies designed to evaluate systolic blood pressure biofeedback and relaxation in the treatment of elevated blood pressure. It reports on the posttreatment follow-up results. The main findings were that patients who received the behavioral treatments could achieve and sustain reductions in blood pressure for at least 18 months. Furthermore, a number of patients who were receiving diuretic therapy to control their pressures were able to maintain reduced pressure for at least 9 months after discontinuing medication. A model for a behavioral-stepped care program is proposed.

Behavior Therapy↗
PubMed1982

Changes in hippocampal rhythmic slow activity during instrumental cardiovascular conditioning in the monkey (Macaca mulatta).

Analyses of 4-8 Hz electrical activity (RSA) of the mid-ventral hippocampus, motor activity (M), and blood pressure were carried out during experiments in which three monkeys were operantly conditioned to slow heart rate (HR), to speed HR or during control, no feedback (FB) periods. The results showed that RSA activity was greater during contingent HR (FB) slowing than during HR slowing noncontingent (FB) for all three animals. Motor activity tended to show small changes across conditions; however, it was higher during HR speeding and lower during HR slowing in two animals. There was no differential effect of FB on motor activity for any animal. Blood pressure changes were small and variable throughout conditioning, RSA changes tended to be highly consistent both early and late in conditioning. Results are discussed in terms of attentional and somatic factors that may be operative during instrumental cardiovascular conditioning.

Animals↗
PubMed1982

Behavioral treatment of high blood pressure II. Acute and sustained effects of relaxation and systolic blood pressure biofeedback.

The effects on blood pressure of regular patient and professional monitoring of blood pressure, extensive patient-involved assessment of results, relaxation, and systolic blood pressure biofeedback are analyzed by comparisons of data from two 3-month treatment periods with results from a 1-month baseline period and by comparisons among control and treatment groups. Ninety borderline hypertensive patients completed the treatments. Major findings are: A Acute effects; 1) Both relaxation and systolic blood pressure biofeedback lowered blood pressure acutely. 2) Improvement in performance of relaxation and biofeedback with practice showed that they are learned skills. 3) Acutely, relaxation and biofeedback were equally effective for lowering systolic blood pressure, but relaxation lowered diastolic blood pressure more. B. Long-term effects; 1) Blood pressure declined for at least 6 months with regular monitoring and patient-involved assessment. 2) The greatest lowering of blood pressure by behavioral intervention occurred during periods when pressures tended to be highest. 3) A combination of relaxation and biofeedback, with biofeedback preceding relaxation, was better than either used alone and slightly, but not significantly, better than relaxation preceding biofeedback. 4) The long-term effects of biofeedback were slightly greater than those of relaxation. A staged, incremental behavioral treatment of borderline hypertension is proposed.

Behavior Therapy↗
PubMed1981

Instrumental control of cardioacceleration induced by central electrical stimulation.

Each of four monkeys (Macaca mulatta) was operantly conditioned to slow and to speed heart rate through a shock-avoidance procedure. During these sessions, electrical brain stimulation that produced tachycardia and pressor responses was delivered on alternate, 64-second segments to one of several brain regions. All animals were able to attenuate the increases in heart rate produced by brain stimulation during the slowing sessions when posterior hypothalamic and striatal regions were stimulated but not when anterior hypothalamic or subthalamic areas were stimulated. During speeding or control sessions during which heart rate was monitored, brain stimulation continued to increase heart rate.

Animals↗
PubMed1981

Clinical biofeedback: a behavioral analysis.

Clinical biofeedback studies have shown that patients can learn to control highly specific physiological responses such as relaxation of the internal anal sphincter, contraction of the external anal sphincter, heart rate and intracardiac conduction patterns, or blood pressure. Findings from a number of studies indicate that the ability to learn to control abnormal responses is highly reinforcing and facilitates further learning. Other findings indicate that learning tends to be specific to the response being trained. If it is desirable to teach patients to control more than one response, it may be necessary to teach each response independently.

Behavior Therapy↗
PubMed1981

Skin potential level: age and recording site interactions.

Two experiments comparing the skin potential level (SPL) of young (30 to 47 years), middle-aged (48 to 65 years), and old (66 to 82 years) men during rest and during stimulus presentations using a nonhydrating electrolyte medium demonstrated that there was an ordered relationship between SPL negativity and age with the older men having less negative levels. Age differences in SPL were dependent upon recording site with larger age differences occurring when SPL was recorded from the medial phalanx than when SPL was recorded from the thenar eminence.

Adult↗