Search PubMed⌕ Search

Biomedical subjects

S Wolf

Publications and source records attributed to S Wolf.

At least 469 records · Page 26Linked to original sources
PubMedDate not supplied

Using our brains.

Explore the source record for details and available documents.

Animals↗
PubMedDate not supplied

Oscillatory functions affecting outcome of coronary heart disease: the hazard of too much or too little stability.

The objective was to identify physiological and behavioral indicators predictive of sudden arrhythmic death in patients who had experienced myocardial infarction in the past. In a 10-year prospective study of 79 patients, 59 men and 20 women aged 36 to 76 who had suffered a well-documented myocardial infarction (MI) at some time in the past (6 weeks-5 years) were individually matched with healthy controls of age, sex, race, height, weight, educational background and type of job. Both patients and controls were reexamined and retested at intervals of 6-8 weeks throughout the first 7 years of the study. Fifty-three patients died, 7 of noncardiac disorders, 2 died of suicide. Forty-four, 31 men and 13 women died suddenly of apparent MI. Thirty-one, or 70% of them were autopsied. Eleven were found to have experienced a recent MI and 20 had only an old scar. Age was not a determinant of cardiac mortality among the patients. The average age of those who died was 56 and of survivors 53. Neither was the level of serum cholesterol concentration, the LDL/HDL ratio, or the treadmill test a significant determinant of death. The measured physiological data that did significantly correlate to the cardiac deaths at the 0.01 level of confidence were low RR variability or wide mean RR variation month to month, prolonged QT interval or wide mean QT variability month to month. The findings support the view that proper physiological balance requires some degree of instability, but not too little or too much. Walter Cannon in his first paper on homeostasis (Cannon, 1926), credited Charles Richet with this perception "The living being is stable... In a sense it is stable because it is modifiable--the slight instability is the necessary condition for the true stability of the organism" (Richet, 1990).

Adult↗
PubMedDate not supplied

Rules of evidence in psychophysiological investigations.

Conventional rules encourage an investigator to focus primarily on quantifiable data. In psychophysiological studies, however, the most relevant data may be nonquantifiable, at least at the present time. Behavior, visceral or general, does not necessarily depend on the quantity of a particular stress, but rather is the result of a complex interactive central processing of afferent signals, reflecting more the relevance of actuating factors than their quantitative features. Thus, the rules of evidence must ask not only for measurement, when possible, but for context as well and for data on related intangibles that determine the significance of an experience to an affected individual. Such an inquiry requires the perspicacity of a skilled and disciplined observer. As the practiced ear of a well-trained cardiologist can draw reliable anatomical inferences from listening to the heartbeat, so the eyes and ears of an educated physician should be able to determine the significance of events to his patient with a fair degree of reliability. Both the physician and the cardiologist, however, must deal with the potential distortion brought on by their own biases. Despite problems of bias, lack of replicability, and the need to persist in efforts toward precise measurement, progress continues in understanding the contribution of psychosocial stresses to a variety of gastrointestinal, cardiovascular, respiratory, cutaneous, and other bodily disturbances and the pathways and neurohumoral mechanisms whereby they are mediated. The agenda now calls for developing new strategies for dealing with the powerful intangibles that activate the mechanisms. Meanwhile, as Robert Morrison once cautioned, "We must not expect a science to know more than it does."

Behavior↗
PubMedDate not supplied

Manipulating the QT interval of the ECG by cognitive effort.

Abnormal prolongation of the QT interval of the ECG has been reported to indicate a hazard of sudden arrhythmic death. Therefore, with the aid of biofeedback from a newly devised instrument capable of measuring and recording the QT interval of the ECG in real time, ten healthy subjects, aided by biofeedback, attempted to shorten and also to lengthen QT. Although the changes achieved were relatively small, the ten subjects as a group were successful in both shortening and lengthening QT at the 0.01 level of significance. The degree of success varied, however, from person to person and from time to time in the same individual. If the findings reported here can be applied more generally to patients at risk for sudden death, and if biofeedback effects can be made to persist without reinforcement, it or other cognitive techniques may prove clinically useful for shortening QT.

Adult↗
PubMedDate not supplied

The effect of alcohol and barbiturate on the frequency of atrial and ventricular premature beats during sleep.

Repeated EEG and ECG monitoring during sleep was carried out in two subjects with ischemic heart disease and one presumably healthy control. All three displayed frequent ectopic heart beats. Two had ventricular and the third atrial premature beats. The study had two objectives: (1) to ascertain the distribution of ectopic beats among the stages of sleep; and (2) to ascertain the effect of alcohol and barbiturates on the frequency of premature beats. Both drugs are known to alter the pattern of sleep stages. It was found that neither atrial nor ventricular premature beats favored a particular sleep stage. Neither drug had a consistent effect on their frequency and there was no correlation with heart rate. For the most part premature beats were fewer on the second night of a procedure although a day filled with anxiety appeared to greatly increase the frequency of premature contractions.

Adult↗