Chronic exposure to 25-80-microT, 200-Hz magnetic field does not influence serum melatonin concentrations in patients with low back pain.

There is substantial evidence that magnetic field (MF) exposure influences melatonin secretion in animals. However, data on its influence on human melatonin levels are scarce, and seemingly contradictory. Because of its many beneficial effects, very low-frequency MF exposure is used in physiotherapy of some neurological diseases and overloading syndromes of the locomotor system. In previous studies, we observed a decrease in human serum melatonin nocturnal concentrations after exposure to MF (2.9 mT, 40 Hz), and we suggested that differences among various studies may depend on different characteristics of the applied MF. Therefore, in the present study, we examined whether or not MF of different parameters exerts the same effect. The study was performed in seven men (mean age: 36.7 +/- 3.8 years; range: 32-42) suffering from low back pain. Patients were exposed to a pulsating MF (induction: 25 80 microT; frequency: 200 Hz, modulated, automatically programmed; complex saw-like impulse shape; bipolar) generated by a Quatronic MRS 2000 apparatus ("magnetic bed") for 3 wk (5 days/wk, twice a day at 08:00 and 13:00 hr for 8 min each), applied to the whole body in patients laying in a horizontal position. The study was performed in spring. Diurnal serum melatonin profiles were estimated 1 day before exposure to MF (baseline), and 1 day and 1 month after the last exposure. No changes in melatonin concentrations were observed either after 1 day or after 1 month following the exposure in comparison to baseline.

[Evaluation of the prognostic value of general motor activity for rehabilitation of patients after cerebral stroke]. / Ocena wartosci prognostycznej podzialu na kliniczne grupy motoryki ogólnej ciala dla rehabilitacji chorych po udarze mózgu.

Following cerebral stroke motor activity of the patient is dependent on the extensiveness of brain ischemia. Evaluation of this activity may be an exponent of brain ischemia extent. It can be used for the determination of predictability of patient survival and results of rehabilitation. Using Mathew and Barthel scales effectiveness of treatment and rehabilitation was evaluated four times during 12-month follow-up in patients of General Motor Activity Clinical Group II i III. The results obtained may be evidence of significant prognostic importance of evaluation of general motor activity of the organism in the initial period of treatment and rehabilitation only, i.e. within 3 months following cerebral stroke. However, it is no importance for evaluation of remote results (one year following cerebral stroke). The evaluation of general activity cannot be used to predict the dynamics of the improvement of neurological and functional status of patients undergoing rehabilitation following cerebral stroke.

Chronic exposure to 2.9 mT, 40 Hz magnetic field reduces melatonin concentrations in humans.

Diurnal rhythm of serum melatonin concentrations was estimated in 12 men with low back pain syndrome before and after exposure to a very low-frequency magnetic field (2.9 mT, 40 Hz, square wave, bipolar). Patients were exposed to the magnetic field for 3 weeks (20 min per day, 5 days per week) either in the morning (at 10:00 hr) or in the late afternoon (at 18:00 hr). Significant depression in nocturnal melatonin rise was observed regardless of the time of exposure. This phenomenon was characteristic for all the subjects, although the percent of inhibition of melatonin secretion varied among the studied individuals.