Biomedical subjects

C Becker-Carus

Publications and source records attributed to C Becker-Carus.

At least 19 recordsLinked to original sources

PubMed2001

Haptic discrimination of size and texture in squirrel monkeys (Saimiri sciureus).

The present study analyzed haptic abilities of four squirrel monkeys. Using a two-alternative forced-choice procedure, stimuli were presented in a visually opaque box, allowing unrestrained test subjects to grab through a small opening and touch the discriminanda. Difference thresholds were determined by a modified method of limits. In the first experiment we determined size difference thresholds for the discrimination of circular cylinders using standard stimuli differing in diameter from 10 mm to 35 mm. In the second experiment a texture difference threshold was obtained for the discrimination of grooved surfaces (groove width 2-7 mm). The squirrel monkeys achieved a mean size difference threshold of 8% stimulus difference. The linear increase of absolute thresholds as a function of the starting stimulus size showed that haptic size discriminations in squirrel monkeys correspond to Weber's law. Three of the animals achieved a texture difference of 10% stimulus difference, while one monkey showed a distinctively lower haptic acuity. An analysis of the exploratory behavior points to a subject-related difference in the significance of cutaneous and kinesthetic information during size discriminations. Whereas differences in the animals' exploratory behavior did not correlate with the size difference threshold a subject achieved, different thresholds for texture discrimination can be explained by the different exploratory procedures the monkeys used to touch grooved surfaces. The low difference thresholds determined for the squirrel monkeys in the present study point to the significance of unrestrained test conditions for the assessment of the haptic capacity of a species.

Animals↗

PubMed1997

Episodic variations of prolactin, thyroid-stimulating hormone, luteinizing hormone, melatonin and cortisol in infertile women with subclinical hypothyroidism.

Preliminary data have suggested that female infertility due to corpus luteum insufficiency may be caused by subclinical hypothyroidism [exaggerated thyroid-stimulating hormone (TSH) response to thyrotrophin-releasing hormone (TRH) stimulation]. L-Thyroxine supplementation has been recommended to achieve pregnancies in subclinical hypothyroid women. This controlled study was carried out in order to investigate the biochemical diagnosis of subclinical hypothyroidism as a possible infertility factor. Five infertile patients (aged 25-36 years) with subclinical hypothyroidism (n = 4, stimulated TSH >20 microU/ml) or primary hypothyroidism (n = 1) and five healthy controls (aged 22-39 years) with normal thyroid function (stimulated TSH <15 microU/ml), regular cycles and no history of infertility were studied in the early follicular phase. In the pre-study evaluation, eight of 23 volunteers (34.8%) had to be excluded because of subclinical hypothyroidism with stimulated TSH values (TSHs) >15 microU/ml. Cycle function of patients and controls was compared by the method of LH pulse pattern analysis. Therefore blood samples were drawn every 10 min during a 24 h period. Sleep was recorded from midnight to 7 a.m. Repetition of the TRH tests at the end of the 24 h blood sampling period confirmed the difference in stimulated TSH values of the two study groups. Pulse analysis for luteinizing hormone (LH), TSH and prolactin showed no differences between patients and controls for pulse frequency, amplitude, height, length, area under curve (AUC) and the 24 h mean. Even the hypothyroid patient had a normal LH pulse pattern. Additional measurement of melatonin in pooled sera every 30 min gave the well-documented diurnal profiles during day and night for both groups. Patients had significantly higher melatonin values at seven time points during the night. Peaks for LH, TSH, prolactin and cortisol were correlated with the sleep stages wake, rapid eye movement, 1 + 2 and 3 + 4. We concluded that corpus luteum insufficiency in female infertility cannot be explained by subclinical hypothyroidism and thus should not be treated with L-thyroxine for fertility reasons.

Adult↗

PubMed1996

[Restitutive effect of sleep on chronic performance stress].

During a polysomnographic (2 nights) sleep registration of 5 chronically stressed compared to 5 control persons 24 h blood cortisol values and salivary cortisol at daytime were measured and compared with measured stress vulnerability. While daytime cortisol levels were reduced under stress conditions, during night sleep combined with a significant change in sleep architecture cortisol excretion raised markedly compared to controls, and the cortisol response to CRF provocation is no more blunted but activated beyond controls, demonstrating the restitutive and protective effect of sleep.

Adaptation, Psychological↗

PubMed1995

[Patients of an ambulatory sleep center--critical variables of insomniacs].

The following study presents results of a broad diagnostical screening for 128 insomniacs, which includes polysomnography, sleep-wake diaries and psychosometrical testing. It was our special aim to investigate about critical but not classical variables for insomnia, which had been mentioned in sleep literature before. We therefore focused on hypotheses about the meaning of state 1 sleep (according to Zorick et al. 1984) and the number of REM-Non-REM Cycles (according to Rüther et al. 1985) for the diagnosis of insomnia. Statistical analysis (t-Test, p = 0.05) showed that patients with less than 3 REM-Non-REM Cycles consumed significantly more hypnotics during 6 months before the sleep examination. Moreover it was obvious (Chi-Square, p = 0.001) that more than 50% of insomniacs with organic causes presented less than 3 cycles, whereas the latter was true only for 1 patient with primary insomnia. Although results were not as strong for the "state-1 sleep variable", we find that these non-classical sleep variables should be sincerely regarded within the future context of the diagnosis of insomnia.

Adult↗

PubMed1995

[Sleep of sleep research personnel--results of the Munster Congress survey].

Due to different knowledge of sleep and sleep disorders (i.e. focussing) sleep quality of sleep-researchers may be better or worse than the sleep of other scientists. On the Münster Congress for Sleep-research and Sleep medicine in March 1994 we investigated this question using the Pittsburger Sleep Quality Index (PSQI). 46 sleep researchers, 52 practitioners and 103 scientists of other disciplines from the Münster University filled out the questionnaire. Results show no difference in overall sleep quality between the three groups, but only sleep quality in the group of sleep researchers shows a bimodal distribution suggesting a subpopulation with more serious sleep problems. 10 to 15% of the total academic population can be regarded as "poor" sleepers. Especially the group of practitioners, in which we found the highest values of daytime sleepiness, seems to be a risk-population for sleep disorders.

Adult↗

PubMed1989

[Psychophysiologic reaction patterns in coping with events by intensive care patients].

The aim of this study was to demonstrate the clear relations between psychological and physiological parameters determined in intensive care patients. For this purpose, heart rate, salivary-cortisol secretion and blood pressure were measured as physiological stress indicators; psychological parameters were covered by examining the patients' way of coping, that is to contrast emotional with rational coping. By comparison, the equivalent parameters were determined in a group of healthy patients. When comparing both groups, we found a higher salivary-cortisol secretion and an increased heart rate in the group of intensive care patients, with the circadian rhythm of the cortisol-secretion remaining almost stable. When examining the patients' group according to the way of coping, we found a higher activation of the sympathetic nervous system in those patients who coped with their situation emotionally than in those who faced their problems rationally. The level of physiological excitation significantly decreased after the patients had been transferred from the ICU to the normal ward. The increased physiological excitation of ICU patients serves to release energies that help them to cope with their situation and can likewise be associated with emotional reactions such as being extremely watchful and in a state of mobilization as well as feeling particularly helpless. The extent of physiological irritation is modified by the way of intrapsychical coping.

Adaptation, Psychological↗

PubMed1985

[Effectiveness of acupuncture and attitude-relaxation training in the treatment of primary sleep disorders].

UNLABELLED: The present study focuses on the differential efficiency of specific psychological and medical procedures for the treatment of chronic sleep disorders (primary symptoms). 32 selected subjects with chronic sleep disorders were assigned to one of the following groups according to their own choice: cognitive change and relaxation training (n = 12), needle acupuncture (n = 8), laser acupuncture (n = 12), and a waiting control group (n = 12). Before, during, and after the respective therapy each subject kept a record with 13 items about his/her sleeping behaviour which had to be filled out every morning. RESULTS: All treatment groups showed an increase in the subjective recovery by sleep as well as a decrease in the use of drugs. On a follow up after two weeks the cognitive change/relaxation group showed a significant decrease in the time required to fall asleep and in the frequency of waking up.

Acupuncture Therapy↗

PubMed1979