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Aim of our study was to measure conduction velocity and pattern of excitation during hypothermia in hearts of ground squirrels Citellus undulatus, known to be most resilient hibernators. We imaged electrical conduction in intact isolated hearts of summer active and winter hibernating ground squirrels at temperatures varying from +37 degrees C to +3 degrees C. Electrical activity was mapped using CCD camera (500 frames/sec) and voltage-sensitive dye di-4-ANEPPS during normal sinus rhythm and ventricular pacing. No spontaneous tachyarrhythmia was observed in all hearts at any temperature. Hearts were able to maintain spontaneous sinus rhythm and normal pattern of epicardial excitation throughout the whole range of studied temperatures. Despite responsiveness to pacing in all hearts ventricular conduction velocity was significantly reduced (about 10-fold) at low temperatures +3 degrees C. Our data provides the first direct demonstration that isolated heart of the summer active and winter hibernating ground squirrel Citellus undulatus is able to maintain normal excitation pattern in a range of temperatures from +37 degrees C to +3 degrees C.

Immunomodulating drug Levamisole was studied as a component in the combined treatment of juvenile slow progredient schizophrenia. Apart from normalizing the immune parameters, the drug improved the patients' clinical conditions. Most prominent was its clinical effect in patients with immune system sensitive to the drug. The patient's condition ameliorated in relation with the features of his initial state. Treating the patients with depressive-asthenic states has yielded the best results. Weaker was the effect on patients with obsessive-phobic disorders. The least curable were senesto-hypochondriac and dysmorphophobic disorders with sensitive delusions of relation.

The study of T lymphocyte suppressors in juvenile continuously progressive schizophrenia showed that the number of suppressor cells in patients was significantly decreased as compared to a group of mentally normal donors; 20.4% and 28.9% respectively. The parallel study of the number of suppressor cells in the peripheral blood and the proliferative activity of T lymphocytes upon their stimulation with mitogenic lectins of PHA and Con A demonstrated that in the mentally normal donors, these parameters were inversely correlated, whereas in the patients with juvenile continuously progressive schizophrenia, there was no such correlation between the above indices. The data obtained are indicative of the impaired regulatory activity of T lymphocyte suppressors in this group of schizophrenic patients.

The authors investigated the effect of the immunostimulant levamisole on the immunological reactivity of schizophrenics and the resultant decrease in the therapeutic resistance of these patients toward psychotropic therapy. Thirteen patients with juvenile malignant continuously progressive schizophrenia were studied, using a double blind design of examination. The number of suppressor T-cells in patients treated with levamisole increased from 16.6% to 22.8% (p less than 0.001) which was not observed in patients on placebo. It has been demonstrated that the immunological parameters in patients with juvenile malignant continually progressive schizophrenia can be fully recovered. Yet, the changes observed in the clinical picture were heterogeneous and unremarkable. The experimental findings suggest that the use of levamisole may be more effective in patients with less progressive forms of the disease.

The paper deals with the effect of psychotropic drugs on blood levels of suppressive T-lymphocytes in patients with continuously progressive schizophrenia. The patients were examined three times: the first sample of blood was taken after a long psychotropic therapy, the second 3 weeks after the discontinuation of the therapy and the third one 3 weeks after the resumption of treatment. The lowest levels of suppressory T-lymphocytes (averaging 16.3%) were observed during the first examination. Following the discontinuation of therapy the content of T-suppresspors increased to 21.3% (P less than 0.001) failing, however, to reach the mean level characteristic of normal donors (25.7%). The amount of suppressory T-lymphocytes decreased again after treatment resumption. It is concluded that one of the factors contributing to changes in the immunological status in patients with juvenile continuously progressive schizophrenia may be a long-term use of psychotropic drugs.