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Biomedical subjects

A Baum

Publications and source records attributed to A Baum.

At least 37 records · Page 2Linked to original sources
PubMed1997

Stress and genetic testing for disease risk.

Healthy people who believe they are at risk for a life-threatening disease appear to carry a substantial stress burden because of threat of disease and uncertainty of risk. Testing for risk factors may be helpful by reducing this uncertainty, but diseases with multiple causes, like breast cancer, appear to be determined by genetic factors and by age, reproductive behavior, exposure to environmental toxins, or unknown antecedents. For diseases caused by inherited genetic defects, testing brings different benefits and stressors. A model is proposed that predicts long-term distress when risk analysis suggests a very high risk, when uncertainty is not reduced, when results of testing are at odds with preventive actions already taken, and when people who receive a positive, risk-increasing result lack strong social support, coping skills, other psychosocial resources, or all of these.

Adaptation, Psychological↗
PubMed1997

Coping self-efficacy buffers psychological and physiological disturbances in HIV-infected men following a natural disaster.

The importance of coping self-efficacy (CSE) appraisals on psychological and physiological functioning for HIV seropositive patients facing a severe environmental stressor was tested comparing 37 HIV-infected gay men and 42 healthy male control participants following Hurricane Andrew. Results suggested that greater levels of CSE were related to lower emotional distress and posttraumatic stress disorder (PTSD) symptoms in both groups. In addition, greater CSE was associated with lower norepinephrine to cortisol ratios in the HIV group but not in the healthy control group. Results are discussed in relation to the coping process for HIV-infected individuals specifically and chronically ill populations in general who face severe environmental stressors.

Adaptation, Psychological↗
PubMed1996

Self-reported stressors, symptom complaints and psychobiological functioning I: Cardiovascular stress reactivity.

Taking into account neuroticism and lifestyle variables (smoking and alcohol consumption), cardiovascular and psychological reactions to stressful films were studied in four groups of subjects selected on self-reported levels of recent stressor load and symptom complaints (low-load/low-symptoms: low-load/high-symptoms; high-load/low-symptoms; high-load/high-symptoms). The films were known either to stimulate or to depress cardiovascular activity. The results showed that psychological reactions (distress; deactivation; openness/involvement) were associated with group membership and condition. In addition, high-symptom subjects were characterized by faster resting heart rates and smaller ECG T-wave amplitudes (TWAs), reflective of greater sympathetic tone on the myocard. Further, low-symptom subjects, in particular those labeled as stress-resistant (high-load/low-symptoms), exhibited larger myocardial responses to the cardiovascular-stimulating films than did high-symptom subjects. Low-symptom subjects showed predicted variations in physiological responses to the different films, whereas the responses by the high-symptom subjects showed lesser variation across films. It is concluded that the cardiovascular responses of low-symptom subjects more accurately followed the energetic demands of the body, whereas the high-symptom subjects were in a comparatively enduring state of arousal.

Adaptation, Psychological↗
PubMed1996

Time course of natural killer cell activity and lymphocyte proliferation in response to two acute stressors in healthy men.

To clarify the time course of immune system activity during and after acute stressor exposure, this study collected immune measures from 31 men at 6 times (before, during, and after 2 common laboratory stressors; mental arithmetic with harassment or a cold pressor task). The 6-min stressor period was associated with increased self-report of pain and distress in both stressor groups and with increased systolic and diastolic blood pressure and heart rate in the mental arithmetic group. Increased natural killer cell activity in this group was observed during the task (2 and 5 min into the task) and 5 min after the task ended. A significant Group x Time effect was observed for lymphocyte proliferation to pokeweed mitogen, and a significant Group x Time x Dilution effect was observed for proliferation to concanavalin A. Inspection of the data suggested that this interaction was due to a reduction in proliferation in both stressor groups during the task period.

Adult↗
PubMed1996

Ventricular fibrillation in the patient with blunt trauma: not always exsanguination.

Three cases of successful prehospital resuscitation of blunt trauma patients sustaining cardiac arrest resulting from ventricular fibrillation are reported. Although probably uncommon, ventricular fibrillation not caused by severe hypovolemia, exsanguination, or severe hypoxia in the setting of blunt trauma might be a treatable cause of cardiac arrest. Early electrocardiographic monitoring of patients with blunt trauma, including those with cardiac arrest, can detect this small, yet easily salvageable group of patients.

Adolescent↗
PubMed1996

Relation between beta-adrenergic receptor density and lymphocyte proliferation associates with acute stress.

The relations between acute changes in beta-adrenoreceptor density on lymphocytes and lymphocyte proliferation to a laboratory speech stressor were examined. Male participants either prepared and delivered a challenging speech task or read from a list of words. Participants engaged in the speech task, but not those involved in reading, exhibited significant increases in systolic blood pressure (an index of sympathetic nervous system arousal) and beta-adrenoreceptor density, accompanied by significant decreases in lymphocyte proliferation to pokeweed mitogen (PWM) but not concanavalin A (Con A). Increases in adrenoreceptor density significantly predicted decreases in lymphocyte activity in response to both mitogens. The increases in beta-adrenoreceptor density in the speech task condition occurred within 5 min after the baseline period, when participants were preparing for the speech task, but not yet speaking. These findings suggest that an acute stressor eliciting sympathetic nervous system activity can evoke rapid changes in beta-adrenoreceptor activity and decreases in mitogenic responses.

Journal Article↗
PubMed1995

Health Care Financing Administration (HCFA) and reimbursement in telemedicine.

Telemedicine has real potential to improve the availability of services and advice of medical specialists to primary care practitioners and their patients. Use of the term "telemedicine" for the purposes of this article will refer to two-way, interactive video systems over which medical consultation takes place. This does not include the use of telecommunications technology to transport still images, particularly radiologic images, from one site to another. We are quite aware that teleradiology and telepathology is already in common use in many sites. We are currently exploring the question of quality standards for teleradiology in addition to other forms of telemedicine.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1995

Lewis rats of the inbred strain LEW/Han: life expectancy, spectrum and incidence of spontaneous neoplasms.

Although Lewis rats are frequently used in biomedical research, little is known about their life-data and spontaneous pathology. Therefore, it was the aim of this study to determine the life expectancy, spectrum and incidence of spontaneous neoplasms of the inbred rat strain LEW/Han. A total of 629 LEW/Han rats (305 females and 324 males) from a specified pathogen-free breeding colony were kept from weaning up to their natural death under defined environmental conditions. A complete histological examination was performed on all organs and macroscopically altered tissues of all animals which died during the first three years of the study. These were 296 female (98%) and 213 male (66%) rats. The mean lifespan of the females (27.7 +/- 5.1 months) was significantly shorter than that of the males (32.5 +/- 6.6 months). In both sexes, the lifespan was mainly determined by the occurrence of neoplasms. Of the large spectrum of 52 histologically different tumour types, the highest incidences were observed for adenomas of the pituitary gland and adenomas/adenocarcinomas of the adrenal cortex in both sexes, mammary gland tumours and endometrial carcinomas in females, and C-cell adenomas/adenocarcinomas of the thyroid gland and tumours of the haemopoietic system in males. Of these, the high incidences of tumours of the haemopoietic system in males (27.7%) and of endometrial carcinomas in females (45.2%) should be considered as characteristic features of the strain.

Animals↗
PubMed1995

A histopathological study on alterations in DMBA-induced mammary carcinogenesis in rats with 50 Hz, 100 muT magnetic field exposure.

Several epidemiological studies have indicated that residential or occupational exposure to 50 or 60 Hz magnetic fields (MF) may increase the risk of breast cancer, possibly by suppression of pineal production of the oncostatic hormone melatonin. In view of the methodological problems of epidemiological studies on MF exposure and cancer risk, laboratory studies are needed to determine whether 50/60 Hz exposure can initiate, promote or copromote mammary cancer. In the present study, 216 female Sprague-Dawley rats were divided into four groups. Two of the groups (with 99 animals each) received oral applications of 7,12-dimethylbenz[a]anthracene (DMBA) and were either sham-exposed or exposed in a 50 Hz, 100 muT MF for 24 h/day 7 days/week for a period of 91 days. The other two groups (nine animals each) were either sham-exposed or MF-exposed without DMBA treatment. The exposure chambers and all other environmental factors were identical for MF-exposed and sham-exposed animals. At the end of the 3 month period of MF exposure, all rats were used for histopathological diagnosis of lesions. At the time of necropsy, significantly more MF-exposed DMBA-treated rats exhibited macroscopically visible mammary tumours than DMBA-treated controls. Furthermore, the size of mammary tumours was significantly larger in MF-exposed rats. Histopathological examination of the mammary gland showed that the number of neoplastic and non-neoplastic lesions did not significantly differ between groups, indicating that MF exposure had not altered the incidence of mammary lesions but had only accelerated tumour growth, consistent with a co-promoting effect. In the MF-exposed group, significantly more rats exhibited malignant mammary tumours than in controls, indicating that MF exposure had affected the progression of DMBA-induced lesions. The number of metastases of mammary tumours or of primary lesions in other organs in response to DMBA was not affected by MF exposure. In rats without DMBA application, no non-neoplastic or neoplastic lesions were determined. The data demonstrate that long-term exposure of DMBA-treated female rats promotes the growth and progression of mammary tumours, while tumour incidence is not affected, at least under the experimental conditions of the present study. The data thus add to the accumulating evidence that MF exposure exerts tumour co-promoting effects.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1994

Petite mutants of sophorolipid-producing Candida yeasts.

Treatment of both Candida apicola IMET 43747 and Candida bombicola ATCC 22214 with N-methyl-N'-nitro-N-nitroso guanidine resulted in formation of auxotrophic mutants and cytochrome oxidase negative mutants. The deficiency of intact cytochrome oxidase did not affect the ability to produce sophorose lipid. This indicates that intact mitochondrial energy supplying system is not necessary for the production of the extracellular sophorose lipids by both Candida yeasts.

Candida↗
PubMed1994

The role of the experimenter in field studies of distressed populations.

In laboratory research, the experimenter's role is to behave in a standardized manner, often following a script, in order to collect data without influencing the responses of subjects. However, in field studies of vulnerable or victimized populations, experimenters confront tasks and dilemmas at odds with this concept of their role. Subjects may cry; experimenters may experience strong feelings when witnessing adversity; normative experimental behavior may feel inappropriate. This paper reports on issues identified in a graduate seminar for nonclinically trained health psychology researchers, and describes the program of training provided. Paradoxically, adhering to a more detached, noninfluential style of interaction requires adapting a flexible, rather than a rote, behavioral style. Relevant skills include explicating values, developing relational and communications skills, and training in post-traumatic stress syndromes. By thus redefining the experimenter's role, ethical and practical considerations introduced in field studies of distressed populations can be balanced with laboratory values.

Adaptation, Psychological↗
PubMed1994

Psychological stress and platelet activation: differences in platelet reactivity in healthy men during active and passive stressors.

Blood platelets have been found to play a major role in the pathogenesis of coronary artery disease. This study examined the effects of active and passive stressors on platelet function and assessed the possible effects of perceived control on platelet reactivity to stress. Heart rate, blood pressure, catecholamine levels, and platelet factor 4 (PF 4) were assessed in 55 healthy males during resting baseline (25 min), 7-min stressor/task periods, and recovery (60 min). Results showed significant increases in PF 4 during the stressor/task periods for both active and passive stressor groups. Psychological stress involving both active and passive participation had a direct effect on platelet activation.

Adolescent↗
PubMed1994

Effect of stress on perceived intoxication and the blood alcohol curve in men and women.

To determine the influence of stress on intoxication and blood alcohol concentration (BAC) 60 healthy male and female volunteers were exposed to a cold pressor test, distressing film, or control condition after consuming a moderate dose of alcohol. Two measures of perceived intoxication suggested a sobering effect of acute stressors. In addition, Ss viewing the distressing film showed longer latency to peak BAC than Ss in the control condition. As BAC began to fall, the cold pressor test initially increased rate of alcohol elimination. These stress-induced changes in intoxication and the BAC curve support a biobehavioral model in which stress may increase alcohol use partly because it attenuates alcohol's psychopharmacological impact.

Adult↗
PubMed1994

Transference in interpersonal relations: inferences and affect based on significant-other representations.

Based on an information-processing model of transference and a recent experimental demonstration of transference, defined in terms of "biased inference and memory" (Andersen & Cole, 1990), the present research examined the transfer of affective responses to a new individual, as in schema-triggered affect (Fiske, 1982). Using idiographic stimulus-generation procedures and a nomothetic experimental design, we exposed subjects to a description of a new, unknown person, allegedly seated next door. The description resembled either a positively or negatively toned significant other from the subject's own life or from another subject's life. As predicted, and replicating previous work, subjects misremembered the target person as having more representation-consistent features when the target resembled their own significant other rather than someone else's. Moreover, and also as predicted, subjects transferred more representation-consistent affect to this same target person. The data are discussed in terms of conceptions of transference and basic aspects of social cognition.

Affect↗
PubMed1994

Differential effects of active and passive laboratory stressors on immune function in healthy men.

The immunomodulatory effects of acute laboratory stressors were examined by comparing active and passive stressors in a between-subjects design. Healthy male volunteers (N = 67) were recruited and randomly assigned to an active, passive, or no stressor condition. Subjects were exposed to either the Stroop and mental arithmetic tasks (active). two surgery films (passive). or two nature films (no stress). Cardiovascular reactivity, plasma catecholamines and cortisol. and self-reported distress were measured pre-task and post-task. Lymphocyte proliferation to concanavalin A (Con A). pokeweed mitogen (PWM), and phytohemagglutinin was assessed a1 baseline, after the first task, after the second task, and 30 min later. Lymphocyte proliferation lo Con A and PWM was significantly reduced in response to the stressors. Different response patterns emerged, depending on the type of stressor and the mitogen used. Changes in lymphocyte proliferation were significantly associated with cardiovascular reactivity during the tasks. Results are discussed in terms of potency of the stressors and mechanisms underlying passive versus active laboratory tasks. Implications for future research are addressed.

Journal Article↗