Biomedical subjects

G Japaridze

Publications and source records attributed to G Japaridze.

6 recordsLinked to original sources

PubMed2005

Competing effects of interactions and spin-orbit coupling in a quantum wire.

We study the interplay of electron-electron interactions and Rashba spin-orbit coupling in one-dimensional ballistic wires. Using the renormalization group approach we construct the phase diagram in terms of Rashba coupling, Tomonaga-Luttinger stiffness and backward scattering strength. We identify the parameter regimes with a dynamically generated spin gap and show where the Luttinger liquid prevails. We also discuss the consequences for the operation of the Datta-Das transistor.

Journal Article↗

PubMed2004

Universality of the rho meson coupling in effective field theory.

It is shown that both the universal coupling of the rho meson and the Kawarabayashi-Suzuki-Riadzuddin-Fayyazuddin expression for the magnitude of its coupling constant follow from the requirement that chiral perturbation theory of pions, nucleons, and rho mesons is a consistent effective field theory. The prerequisite of the derivation is that all ultraviolet divergences can be absorbed in the redefinition of fields and the available parameters of the most general effective Lagrangian.

Journal Article↗

PubMed2002

Auditory brainstem, middle-latency, and slow cortical responses in multiple sclerosis.

The efficacy of auditory brainstem responses (ABRs), middle-latency responses (MLRs), and slow cortical potentials (SCPs) has been evaluated in 40 patients with multiple sclerosis (MS). ABRs and MLRs were averaged to clicks and SCPs to 1-kHz tone bursts of 70-dB nHL intensity. ABR, MLR, and SCP abnormalities were detected in 65.0, 42.5, and 30.0% of the sample, respectively. The combined sensitivity of ABRs and MLRs amounted to 80.0%, of ABRs and SCPs to 75.0%, and of MLRs and SCPs to 60.0%. The joint aptitude of all three responses equalled 87.5%. All three responses were capable to detect MS in seven of nine patients, failing to display neurological signs of brainstem lesion. The responses were also abnormal in three of five subjects with negative magnetic resonance imaging. It is concluded that the combined application of ABRs, MLRs, and SCPs promotes both detecting and confirming MS loci.

Acoustic Stimulation↗

PubMed1997

Auditory brainstem response, middle-latency response, and slow cortical potential in patients with partial epilepsy.

Auditory brainstem responses (ABRs), middle-latency responses (MLRs), and slow cortical potentials (SCPs) have been recorded in patients with partial epilepsy previously untreated by anticonvulsants. Peak latencies, interpeak intervals, and amplitudes were estimated and the mean group values were compared with the respective data in age- and gender-matched healthy individuals. Neither ABRs nor MLRs in the patients differed significantly from those in the control group. Conversely, the SCP characteristics demonstrated regular differences: the P2 peak latency in the patients was prolonged and both the P1N1 and N1P2 amplitudes were increased. Considering the mechanisms of the ABR and MLR, it has been suggested that the specific structures of central auditory pathway up to the primary cortex do not play any essential role in the pathogenesis of partial epilepsy. Furthermore, it is speculated that the SCP-generating cortical areas, being primarily of non-specific qualities, are intimately involved in the mechanisms of epilepsy.

Adolescent↗

PubMed1993

Auditory middle-latency response: intramodal and intermodal interactions.

Intramodal and intermodal interactions have been studied in generators of the auditory middle-latency response (MLR). The MLRs were recorded to the wide-band clicks. Similar clicks or electric shocks to the median nerve served as conditioning stimuli. A procedure was employed permitting to avoid distortions of test MLRs due to superimposition upon potentials to the conditioning stimuli. A rapid recovery of responsiveness in MLR generators was revealed in intramodal experiments. Poorly discernible test MLRs were identified at conditioning interval of 10 ms, while already at interval of 50 ms the MLR restoration was completed. No effects of shocks upon MLRs were evident in intermodal experiments. The starting knee was only altered in most test MLRs, outlining a narrow strip of intermodal interaction. The sources of the MLR are discussed and a subcortical rather than cortical, polylevel rather than monolevel, monomodal rather than polymodal nature of the MLR is proposed.

Acoustic Stimulation↗

PubMedDate not supplied

Effects of carbamazepine on auditory brainstem response, middle-latency response, and slow cortical potential in epileptic patients.

Auditory brainstem responses, middle-latency responses, and slow cortical potentials (ABRs, MLRs, SCPs) were recorded in 21 epileptic patients before and during treatment with carbamazepine (CBZ). The peak-latencies, interpeak intervals, and amplitudes were estimated and evaluated statistically. CBZ monotherapy resulted in prolongation of peak latencies of ABR waves I, III, and V as well as of interpeak intervals I-III and I-V. A significant increase in the peak-latencies of MLR components Na, Pa, and Nb and of interpeak intervals V-Pa and Na-Nb was also observed along with the systematic NaPa amplitude reduction. CBZ also prolonged the peak-latencies of SCP components P1 and N1. Based on the obtained results, we suggest that CBZ exerts suppressive influences both on modally specific (lemniscal) and modally nonspecific (extralemniscal) auditory structures.

Acoustic Stimulation↗