Neuronal damage in the hippocampus of inbred mouse strains in the models of epilepsy induced by kainic acid and pilocarpine

Elucidation of the mechanisms of neuronal damage is an important task of modem neuroscience and is of paramount importance for medicine. Present work compares two models of excitotoxic neuronal damage induced by kainic acid and pilocarpine, in which inbred C57BL/6J (C57BL) and FVB/NJ (FVB) mice were used. Both models produced higher neuronal damage in FVB although mortality was higher in C57BL. No significant differences between two strains of mice were found in seizures severity. Kainic acid demonstrated greater tropism to hippocampus in comparison with pilocarpine. Hsp-70 and Egr-1 expression was not significantly different in C57BL and FVB. Analysis of the isolated mitochondrial fraction has shown different degree of free radical production in the strains studied, that could be one of the reasons for unequal susceptibility of their neurons to excitotoxic cell death.     

Neuropeptide Modulation of Evoked Responses of Neurons in the Medial Septal Region of Hibernating Ground Squirrels in Conditions of Chronic Isolation of the Medial Septal Region from Preoptic-Hypothalamic Structures

Septal slices from hibernating ground squirrels were initially (for two weeks) subjected to basal separation of the septal region and were then used for studies of the effects of neuropeptides extracted from the brains of hibernating animals (TSKYR, TSKY, and DY) and monoaminergic neurotransmitters (noradrenaline and serotonin) on neuronal responses evoked by intraseptal electrical stimulation. Despite removal of a large complex of afferent connections and direct contacts with the preoptic region, the neurons retained their normal reactivity and the normal distribution of response types. Neuropeptides efficiently modulated responses, and had strong facilitatory effects on oligosynaptic short-latency responses consisting of single spikes. In most cases (78% of tests), effects on evoked activity were independent of effects on baseline discharge frequency. These data lead to the suggestion that neuropeptides have two influences on septal neurons: a direct, non-synaptic influence on the pacemaker potential responsible for baseline activity, and modulation of synaptic processes. Analysis showed that retention of descending septohippocampal connections was not critical for entry into hibernation and the tonic maintenance of this state. The effects of preoptic-hypothalamic mechanisms of hibernation determine the paradoxical latent excitability of septal cells, allowing the septohippocampal system to filter external signals and provide for urgent arousal of the forebrain during hibernation.     

Changes in DNA and surface properties of peripheral blood leukocytes in monkeys after whole-body γ-irradiation

Central Roentgeno-Radiologic Research Institute, Ministry of Health of the USSR, Leningrad. Institute of Biophysics, Ministry of Health of the USSR, Moscow. Research Institute of Experimental Pathology and Therapy, Academy of Medical Sciences of the USSR, Sukhumi. (Presented by Academician of the Academy of Medical Sciences of the USSR V. A. Lapin.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 108, No. 8, pp. 158–159, August, 1989.     

Pulse oximetry: Achievements and prospects

Institute for Management Sciences, Russian Academy of Sciences and All-Russian Scientific-Research Institute for Medical Instrument Engineering, Moscow. Translated from Meditsinskaya Tekhnika, No. 4, pp. 27–31, July–August, 1993.     

Study of CATCH 22: genetic aspects

Introducing molecular genetic techniques into clinical practice has made it possible to detect del 22q11.2, an etiological factor for congenital cardiovascular diseases in CATCH 22. The authors' complex (clinical, syndromological, molecular genetic, and computed) approach to examining this group of syndromes has enabled patients at high risk for CATCH 22 to be identified. A list of gene candidates responsible for manifestations of CATCH 22 and data on how pathological phenotypes are developing in model objects are presented.     

Effect of ischemia and postischemic reperfusion on some mechanisms of regulation, rhythmogenesis, and contractile function of the heart in rats

Isolated rat hearts were perfused with Krebs' solution after Langendorff's method. Decrease of the perfusion rate from 8.8 to 2.2 ml/min for 40 minutes led to inhibition of the contractile and rhythmic function of the heart and its reactivity to isoproterenol (IP) and acetyl choline (AC), drop in the intensity of lipid peroxidation appraised according to malonyl dialdehyde (MDA) level, and reduction of noradrenaline (NA) concentration in the myocardium in maintenance of the cAMP level. Forty-minute postischemic reperfusion normalized cardiac function, caused further diminution of the heart reactive properties to IP and AC, activated lipid peroxidation, reduced the NA concentration, and maintained a normal MDA level. The effect of ischemia and reperfusion on the regulatory mechanisms, rhythmogenesis, and contractile function of the heart is discussed.