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Biomedical subjects

K Kräuchi

Publications and source records attributed to K Kräuchi.

9 recordsLinked to original sources

Diurnal variation of symptoms in seasonal affective disorder.

The classic melancholic pattern of depressive symptoms being worse in the morning was present in 3/4 of a sample of 47 seasonal affective disorder patients (SAD), as assessed by global ratings and self-ratings of diurnal variation (DV). The type of DV did not predict response to light, but it did predict relapse within a week: Only those SAD patients with symptoms worse in the evening or no DV did so.

Adult

Morning or night-time melatonin is ineffective in seasonal affective disorder.

Melatonin, at the same doses used to treat circadian-rhythm related sleep disturbances, had no effect on the depressive symptoms in seasonal affective disorder (SAD) patients, whether given early (7 a.m.) or late (11 p.m.) for a week. Slight improvements in sleep were seen with nighttime administration. The circadian rhythmicity of urinary 6-sulphatoxymelatonin was not modified in any way. Melatonin at this dosage (5 mg/day) or at these two times is therefore not a potential alternative treatment for SAD; light remains the therapy of choice.

Adult

The relationship of affective state to dietary preference: winter depression and light therapy as a model.

Seasonal affective disorder (SAD) patients often crave carbohydrates when depressed during the winter. We measured dietary intake using a daily Food/Drink Frequency Questionnaire in 36 SAD patients over four conditions: when depressed in winter, during light therapy (1 h 2500 lux, morning or evening), during withdrawal, and when euthymic in summer. Carbohydrate intake (both sweet and starch) in the second half of the day was elevated during winter depression and was as low after light therapy as in summer. The medial hypothalamus is hypothesised to play a key role in coupling 'mood and food' in SAD.

Adolescent

Static magnetic fields decrease nocturnal pineal cAMP in the rat.

Magnetosensitivity of the rat's pineal cyclic adenosine monophosphate (cAMP) system was investigated. During their dark phase, rats were exposed for one hour to a static magnetic field (MF) inverting the horizontal component of the natural MF. MF-exposed animals showed a 38% decrease in pineal cAMP content (1.21 pmol/pineal gland) compared to a non-exposed control group (1.96 pmol/pineal gland).

Animals

The four seasons: food intake frequency in seasonal affective disorder in the course of a year.

Patients with seasonal affective disorder (SAD) report atypical symptoms of increased appetite, particularly "carbohydrate craving," increased body weight, and sleepiness, during their winter depression. To document feeding behavior in detail, a Food/Drink Frequency Questionnaire (FDFQ) was given to female control subjects and SAD patients at each of the four seasons. SAD patients consumed carbohydrate-rich foods (starch and not sweets) more often than controls (annual mean) and also showed a seasonal rhythm with maximum values in winter and minimum values in summer. In contrast, protein-rich food intake was identical in both groups and did not show seasonal variation. Fiber-rich food intake was also increased in SAD patients. SAD patients ate more meals per day, both at breakfast and in the second half of the day. Again, SAD patients showed seasonal changes of meal number with a minimum in summer. Body weight and body mass index did not undergo significant seasonal changes in the group as a whole, nor did SAD patients differ from controls. These atypical symptoms in SAD can be interpreted as a "medial hypothalamus syndrome" involving alpha 2-noradrenergic and serotonergic mechanisms.

Adult

Weak 50-Hz electromagnetic fields activate rat open field behavior.

Rats were tested in an open field after previous exposure to a weak, 50-Hz electromagnetic field of the same order of magnitude as the earth's magnetic field. Animals exposed to the artificial field at the beginning of the light phase showed 40% more rearing activity than controls, together with a slight increase in ambulation and a tendency towards less defecation and a shortened rearing latency. A replication experiment yielded the same results. Animals exposed at the beginning of the dark phase manifested no significant changes in open field activity. The results show that weak electromagnetic stimuli can modify some behavioral responses, and that these responses are sensitive to circadian phase.

Animals

Specific in vivo binding of d-LSD in rat brain.

A reproducible in vivo d-LSD binding method in rat brain is described, with high affinity (Kd of 5 pmoles/g wet wt), stereospecificity (d- vs. 1-LSD) and regional selectivity. It may be a useful adjunct to in vitro methods for measuring changes in turnover at the synaptic level related to the intact receptor.

Animals