Study by nontraditional analytic methods of features of cortical potentials,taking high-frequency components into account,in dogs during instrumental learning

A new method has been developed for the coding of EEG tracings which is an alternative to the classical spectral correlation analysis. This method has made it possible to compensate to a considerable degree for limitations which are unavoidable with the Fourier transform, and to obtain additional information regarding the form of the tracing, which reflects the fluctuations of brain potentials. The new system that has been presented for coding the EEG is, in our view, the most adequate (of the methods known to us) for identifying the individual features of the EEG, in terms of evaluating both their regional differences and similarities. The data obtained convince us once again of the real existence of high-frequency low-power components of the EEG, and their enhancement during instrumental learning in dogs (motor alimentary conditioned reflexes). In addition, data have been obtained pointing to the intensification in some regions of a slow-wave constituent; this has not been observed previously in carrying out a Fourier transform. Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow. Translated from Zhurnal Vysshei Nervnoi Deyatel'nosti imeni I. P. Pavlova, Vol. 44, No. 2, pp. 244–253, March–April, 1994.     

Reciprocal regulation of the nitric oxide synthase/arginase balance in mouse bone marrow-derived macrophages by TH 1 and TH 2 cytokines

Activation with lipopolysaccharide induces macrophages to produce the enzymes arginase and nitric oxide (NO) synthase. Both enzymes use as a substrate the amino acid L-arginine, which can be either hydrolyzed by arginase to urea and ornithine or oxidized by NO synthase to NO and citrulline. NO is important in the bactericidal and cytotoxic activities of macrophages. An equivalent functional role of arginase and its products is not known. We tested the induction of arginase in bone marrow-derived macrophages by endogenous mediators that are known to induce NO synthase, such as interferon-γ (IFN-γ), or suppress the induction of this enzyme, such as interleukin (IL)-4, IL-10, and prostaglandin E₂ (PGE₂). We find that PGE₂ and the TH2 cytokines IL-4 and IL-10 are potent inducers of arginase. In contrast, the TH 1 cytokine IFN-γ does not induce arginase. Simultaneous application of both types of mediators leads to reduced induction of both arginase and NO synthase. Exposure of macrophage cultures to inducers of NO synthase exhausts their ability to respond subsequently to inducers of arginase. Conversely, exposure of the cells to inducers of arginase exhausts their ability to respond subsequently to inducers of NO synthase. The results are consistent with a competition of both enzymes for their substrate, L-arginine, with a reciprocal inhibition in the induction of both enzymes, or a combination of both phenomena. The enzymes NO synthase and arginase appear to define two alternate functional states of macrophages, induced by TH 1 and TH 2 cytokines, respectively.     

Antitumor activity of normal bone marrow cells

After separation of normal murine bone marrow cells in a Percoll density gradient cellular fractions with densities of 1.076 and 1.060 g/ml are capable of suppressing thein vitro growth of leukemia cells. The cytostatic activity of these fractions, however, does not surpass the level of antitumor antiproliferative activity intrinsic to intact bone marrow cells. These cells were found to be capable of joining the splenocytes, thymocytes, and lymph node cells in effector cytostatic cooperation and thus enhance the final antitumor effect. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 120, N ^o 8, pp. 181–183, August, 1995     

Sequences of conserved region in the A subunit of DNA gyrase from nine species of the genus Mycobacterium: phylogenetic analysis and implication for intrinsic susceptibility to quinolones.

The sequences of a conserved region in the A subunit of DNA gyrase corresponding to the quinolone resistance-determining region were determined for nine mycobacterial species and were compared. Although the nucleotide sequences were highly conserved, they clearly differentiated one species from another. The results of the phylogenetic analysis based on the sequences of the quinolone resistance-determining regions were compared with those provided by the 16S rRNA sequences. Deduced amino acid sequences were identical within the nine species except for amino acid 83, which was frequently involved in acquired resistance to quinolones in many genera, including mycobacteria. The presence at position 83 of an alanine for seven mycobacterial species (M. tuberculosis, M. bovis BCG, M. leprae, M. avium, M. kansasii, M. chelonae, and M. smegmatis) and of a serine for the two remaining mycobacterial species (M. fortuitum and M. aurum) correlated well with the MICs of ofloxacin for both groups of species, suggesting the role of this residue in intrinsic susceptibility to quinolones in mycobacteria.     

Tests of autonomic dysfunction in patients with multiple sclerosis

Autonomic dysfunction is frequent in patients with multiple sclerosis (MS). The sympathetic skin response (SSR) and the R-R interval variation (RRIV) are simple electrophysiologic tests for the assessment of central and peripheral autonomic disturbances. Both tests were performed in 60 patients with clinically definite MS and 30 controls. The SSR was recorded simultaneously from both upper and both lower limbs. In all volunteers normal responses were recorded from the four limbs, but 39 patients (65%) showed abnormal responses in at least one limb. The reduction in amplitude of the response was correlated with patients' EDSS. In individual limbs, the SSR amplitude correlated with weakness, spasticity and cerebellar dysfunction, but was not sufficiently related to the deep sensory loss. The RRIV was abnormal in 48 MS patients (80%), as compared to the controls, but showed no significant relationship either to the EDSS or to the SSR. The sensitivity of SSR and RRIV is high and comparable with that of visual and somatosensory evoked potentials.     

Symmetrical interdigital keratoderma of the hands

We report the case of a 26-year-old man affected by a symmetrical keratoderma localized to the interdigital spaces of the fingers. No occupational, traumatic, or irritant factors were discovered. Clinical and histological features were consistent with the diagnosis of symmetrical interdigital hyperkeratosis, a sporadic disorder described by Frei in 1926. We believe this condition to be less rare than the few cases reported in the literature would suggest.