Spatial organization of EEG in rats with genetically determined emotionality

In order to study the possibility of EEG discrimination of genetically determined emotionality (increased propensity to emotional and stress reactions and anxiety) brain electrical activity was recorded in rats of two strains: Maudsley Reactive and Maudsley Nonreactive (24 derivations from the convexital skull surface were used). The program package "Synchro-EEG" was used for EEG processing. It was demonstrated that the two rat strains were significantly different in 120 EEG parameters of 840 ones analyzed. On the basis of 37 parameters, each rat was correctly recognized as belonging to the respective group with the error of 4.89%. The analysis of the detected signs allowed their classification to be performed in accordance with the peculiarities of the emotional and cognitive processes and the level of nonspecific activation. Specific forms of interaction between these components in the system of emotional reactions were revealed.     

Features of gastrin reaction in rats with different susceptibilities to gastric mucosa lesions in immobilization-cold stress]

The connection between the character of gastrin and acid reactions and visible morphological changes of gastric mucosa in immobilising-cold stress was studied in the experiments on mongrel rats. It is established that in the rats the fundal gastric mucosa is resistant to the disturbing action of the immobilising-cold stress. The post-stress gastrin contents in the antrum and duodenum mucosa is higher and in the serum lower than in rats with ulceration. The rats with the stress erosions have the intermediate position. The acid factor didn't play the significant role in the ulcerogenesis because its value didn't overstep the limits established in the extradigestive period.     

Possible involvement of orexin in the stress reaction in rats

We examined whether corticotropin-releasing factor (CRF) was involved in orexin-induced grooming and face-washing behaviors, and whether orexin was involved in the stress reaction. Administration of alpha-helical CRF, CRF antagonist, alone had no behavioral effect, but it blocked the orexin-induced grooming and face-washing behaviors in rats. The level of corticosterone increased in a dose-dependent manner 15 min after icv injection of orexin, and it remained high for at least 60 min. In 2-month-old rats, 1 h of immobilization stress increased orexin mRNA levels, but not the melanin-concentrating hormone (MCH) mRNA, in the lateral hypothalamic area (LHA). In 6-month-old rats, 30 min of cold stress increased the expression of orexin mRNA in the LHA. Unlike in the 2-month-old rats, immobilization stress did not change orexin mRNA expression in 6-month-old rats. These results suggest that CRF is involved in orexin-induced behaviors, and that orexin may play an important role in some stress reactions.     

Paradoxical sleep deprivation, stress and emotionality in the rat

88 adult male rats were divided into 9 groups. Group I and II served as controls. The rats of group III were repeatedly aroused during 4 days at the very onset of each paradoxical sleep period by direct MRF stimulation. This deprivation reduced the daily amount of paradoxical sleep by 70%, while the slow wave sleep was reduced by 10% only. In group IV, the animals were given food and water for one hour a day only. Groups V and VI were subjected to immobilization and cold stress, respectively. Groups VII, VIII and IX were deprived of paradoxical sleep on platforms of 15, 11 and 6.5 cm in diameter, respectively. Stress was estimated by the classical Selye's triad: weight of adrenals and thymus and gastric ulceration. Emotionality was measured in the open field and also by self-stimulation of the lateral hypothalamus. Neither emotional behaviour disturbances nor stress features were found after paradoxical sleep deprivation in the group III. Moreover, this deprivation induced a slight, though significant, reduction in adrenals weight. Also, no changes in emotional behaviour were noted in the stress-exposed group V and VI. Only the interplay between REM-sleep deprivation and stress on the platforms in groups VII, VIII and especially IX led to a considerable shift in emotionality.     

Effect of hyperbaric factors on the biochemical and hematological indicators in rats (in vivo) and in humans (in vitro)]

The influence of hyperbaric factors on complex of biochemical and haematological parameters was examined in rats (in vivo) on donor blood samples. It was established, that the sojourn in heliox under the pressure 6.1 MPa and rO2 60 kPa results in activation of lipid peroxidation, alteration of erythrocyte oxygen transport function and the suppression of lipid metabolism. There are no significant alterations of these parameters in the comparative experiment with the pO2 40 kPa. The decompression of donor blood samples from 5.1 MPa to 0.1 MPa during 50 minutes had no significant influence on complex of biochemical, haematological and immunological parameters as compared to control probes.     

Features of lipid peroxidation in brain and liver tissues from aging rats under stress

The lipid peroxidation (LPO) level between in the adult and old rats brain and liver was determined as to be essentially undiffering. Stress activated the LPO independence the age of animals and tissues investigated. The concentration changes of LPO products testify to it. In the adult rats under the stress capability of tissues to induction in vitro ferment and ascorbat-depending LPO, in comparison with the control, decreases, at old--does not change in the brain and considerably grows in the liver. Stress is accompanied by an oppression of Na, K-ATP-ase PM activity of hepatocytes, more expressed in the old animals.     

EEG Features in Women with a Complicated Pregnancy

Clinical and EEG spectral analysis was carried out in 14 pregnant women (five women at risk of preterm labor and four with miscarriage). It was shown that the baseline EEG pattern of women with the persistent threat of preterm labor was characterized by the high spectral power of the -rhythm and its predisposition to hypersynchronization. In the miscarriage group, virtually a complete absence of the -rhythm and the predominance of generalized both high-frequency and slow low-amplitude rhythms are noted in most pregnant women. The data obtained allow a risk group characterized by either a hypersynchronous unstable -rhythm or its absence to be identified among pregnant women.     

Oxidative stress induced by chronic administration of sodium dichromate [Cr(VI)] to rats

Chromium occurs in the workplace primarily in the valence forms Cr(III) and Cr(VI). Recent studies have demonstrated that sodium dichromate [Cr(VI)] induces greater oxidative stress as compared with Cr(III), as indicated by the production of reactive oxygen species by peritoneal macrophages and hepatic mitochondria and microsomes, and enhanced excretion of urinary lipid metabolites and hepatic DNA-single strand breaks (SSB) following acute oral administration of Cr(III) and Cr(VI). We have therefore examined the chronic effects of sodium dichromate dihydrate [Cr(VI); 10 mg (33.56 μmol)/kg/day] on hepatic mitochondrial and microsomal lipid peroxidation, enhanced excretion of urinary lipid metabolites including malondialdehyde (MDA), formaldehyde (FA), acetaldehyde (ACT), acetone (ACON) and propionaldehyde (PROP), and hepatic DNA damage over a period of 90 days. The maximal increases in hepatic lipid peroxidation and DNA damage were observed at approximately 45 days of treatment. Maximum increases in the urinary excretion of MDA, FA, ACT, ACON and PROP were 3.2-, 2.6-, 4.1-, 3.3- and 2.1-fold, respectively, while a 5.2-fold increase in DNA-SSB was observed. The results clearly indicate that chronic sodium dichromate administration induces oxidative stress resulting in tissue damaging effects which may contribute to the toxicity and carcinogenicity of hexavalent chromium.     

Behavioral characteristics and stress reaction of the pituitary-adrenal system in prenatally stressed rats

Mothers' stress was shown to considerably diminish the orienting-studying activity of male rats in the dioestrus stage, as well as enhancement of anxiety. In prenatally stressed male rats, on the contraty, the anxiety diminished while their behaviour in the open field tests remained practically unaltered. The prenatal stress affected the stressor response of the hypophysis-adrenal systems in both sexes. The data obtained suggest that the mothers' stress affects both behaviour and stressor response in male as well as female rats.     

Graft-versus-host reaction following granulocyte transfusion from a normal donor (author's transl)]

Graft-versus-Host disease following the transfusion of leukocytes from normal donor occured during remission-reinduction therapy in a 5 years old girl with acute lymphocytic leukemia. The clinical picture consisting of rash, diarrhea and somnolence was congruent with the diagnosis. Graft-versus-Host disease was confirmed by histology of skin biopsy and exclusion of other causes. The child survived the disease. We recommend the irradiation of leukocyte concentrates before transfusion.     

Studies on the reaction mechanism of a ribonuclease II from Aspergillus oryzae (author's transl)]

Ribonuclease T2 was isolated from an Aspergillus oryzae extract. In order to define the substrate specificity, the hydrolysis of a series of 2',3'-cyclic nucleotides was measured semiquantitatively. Modifications in all positions of the bases are tolerated, as long as the base stays in the anti conformation or has a chance to return to it; bulky substituents at N-3 of the pyrimidine base lower the rate. So far the conclusion seems justified that the enzyme does not react with the substrates by specific bonds to the base, but rather by hydrophobic binding. The conformation specificity and the pH dependence of the activity support this hypothesis. The pH optima with substrates which may be positively or negatively charged are shifted to pH values at which the substrates are uncharged. This strongly indicates a hydrophobic type of interaction between base and enzyme. From the pH dependence of the kinetic parameters Km and k+2, an enzyme group with a pK of 7 (probably histidine) can be postulated. This group should interact in the protonated form with the phosphate anion. Another B.HB-system (probably two carboxylate groups) seems to be involved in the catalysis step, performing the base catalysis at the 2'-OH group and the proton catalysis at the phosphate oxygen simultaneously.     

Characterization and Robust Classification of EEG Signal from Image RSVP Events with Independent Time-Frequency Features

This paper considers the problem of automatic characterization and detection of target images in a rapid serial visual presentation (RSVP) task based on EEG data. A novel method that aims to identify single-trial event-related potentials (ERPs) in time-frequency is proposed, and a robust classifier with feature clustering is developed to better utilize the correlated ERP features. The method is applied to EEG recordings of a RSVP experiment with multiple sessions and subjects.The results show that the target image events are mainly characterized by 3 distinct patterns in the time-frequency domain, i.e., a theta band (4.3 Hz) power boosting 300–700 ms after the target image onset, an alpha band (12 Hz) power boosting 500–1000 ms after the stimulus onset, and a delta band (2 Hz) power boosting after 500 ms. The most discriminant time-frequency features are power boosting and are relatively consistent among multiple sessions and subjects.Since the original discriminant time-frequency features are highly correlated, we constructed the uncorrelated features using hierarchical clustering for better classification of target and non-target images. With feature clustering, performance (area under ROC) improved from 0.85 to 0.89 on within-session tests, and from 0.76 to 0.84 on cross-subject tests. The constructed uncorrelated features were more robust than the original discriminant features and corresponded to a number of local regions on the time-frequency plane. Availability: The data and code are available at: http://compgenomics.cbi.utsa.edu/rsvp/index.html     

Biochemical indicators of thermal stress in Tilapia aurea (Steindachner)

Tilapia aurea muscle and liver adenylate nucleotides, the adenylate energy charge (EC), plasma glucose, cortisol and chloride were monitored during acute and chronic temperature stress. Muscle EC is unaffected during acute cold water exposure but decreases significantly when tilapia are exposed to chronic, sublethal, low temperature stress. The decrease in EC is primarily the result of a decrease in ATP concentration. Plasma glucose and cortisol increase when tilapia are exposed to 11–12° C for 60 min, 11 days, and a 5-week period. Incomplete compensation is evident in 5-week acclimated fish since glucose and cortisol levels are intermediate between controls and acutely stressed fish. Acclimation to 35° C does not significantly affect plasma glucose and cortisol compared to controls (22° C). Plasma chloride is relatively unaffected by acute and chronic temperature stress. Liver adenylates are not significantly affected when tilapia are subjected to a sudden drop in water temperature (22° down to 11° C). EC is a useful indicator of chronic low temperature stress in T. aurea , while plasma glucose and cortisol are sensitive to both acute and chronic temperature stress.