Possibilities of a pulsogram for estimation of the wave structure of the cardiac rhythm

Visual and computerized analysis of pulsograms revealed the entire daily (24-h) wave structure of the cardiac rhythm in healthy children. Only two waves characteristic of the cardiac rhythm of a healthy child follow each other all 24 h of the day. These are the respiratory and blood pressure waves. Slower waves (from several minutes to several hours in length) are encountered in the cardiac rhythm in the form of interesting regular alternations. Comparison of the periodic structures obtained on the basis of spectral analysis and from the pulsograms illustrates the limited possibilities of the Fourier spectrum in the analysis of nonstationary stochastic processes as compared to the visual analysis of pulsograms.     

Features of the power spectra of the main EEG rhythms in children with different types of attention deficit hyperactivity disorder

As a result of the examination of a group of 9- to 12-year-old children with the combined type of attention deficit hyperactivity disorder (ADHD), two variants of the clinical picture of ADHD were identified: the residual organic variant (ADHD RO) and the idiopathic variant (ADHD IP). The EEG power spectra in the main frequency ranges were studied with the eyes closed and open. The greatest intergroup differences in the power spectra were observed in the θ-band in the forntocentral and occipital derivations. In the frontocentral divisions of the cortex, the maximal values were observed in the group of ADHD RO children, whereas the highest spectral power values were observed in ADHD IP children in the occipital derivations. No statistically significant differences in the α-band spectral power between healthy subjects and ADHD schoolchildren from either group were obtained. Thus, the studies showed that these two ADHD variants have certain neurophysiological differences, which should be considered when therapeutic modalities are to be selected.     

EEG θ rhythm in preterm and full-term infants at the age of five months in endogenous attention

EEG indicators of endogenous attention (EnA) were studied in healthy infants carried to term and extremely preterm infants at a corrected age of five months. The cortical topography of the spectral amplitudes of the EEG θ rhythm was studied during long-term attention of the children to a new visual stimulus (exogenous attention, ExA) and during the retention of anticipatory attention under the conditions of constant appearance and disappearance of a stimulus in the paradigm of visual expectation (EnA). The relationship between reactive changes in the EEG θ rhythm during the retention of EnA and the behavioral parameters of the infant’s ability to retain this type of attention was also assessed. In five-month-old infants, the retention of EnA, in contrast to simpler types of attention to an exogenous stimulus, was accompanied by the appearance of a highly synchronized EEG θ rhythm (3.6–5.2 Hz) with a topical amplitude maximum in the lower temporal associative areas of the cortex. The ability to maintain EnA in children of this age is directly related to the reactive increase in the θ rhythm in the lower temporal areas of the cortex during the retention of EnA as compared to ExA. The deficit of EnA control in healthy extremely preterm (HEP) infants was associated with a relative deficit of the functional synchronization of the θ rhythm in the lower temporal areas of the cortex during the retention of EnA compared to full-term infants. In HEP infants, a decreased synchronization of the θ rhythm was equally typical of EnA and ExA. However, its cortical location depended on the type of attention. The functional nature of the θ rhythm inhibition in HEP infants suggests that this abnormality was related to alterations in the neurotransmitter interactions between the limbic and cortical structures, rather than to structural defects. These alterations could be one of the causes of the partial deficit of EnA in HEP infants.     

Alpha-rhythm of the EEG in directed attention

Degree of manifestation and synchronization of rhythmic alpha-range components in various cortical areas was studied in healthy adult subjects in conditions of controlled computer experiment by spectral-correlation method of EEG analysis during directed attention previous to discrimination of tactile, auditory and visual stimuli. The obtained results show that in preparation for discrimination of heteromodal stimuli, specific reconstructions take place of alpha-range electrical activity determined by signal modality. These changes are expressed in a local increase of the degree of synchronization of alpha oscillations in those projection and associative brain areas which are connected with the analysis of the given stimuli. Functional significance of these reconstructions is seen in the fact that they are significantly more expressed at correct recognition. A hypothesis is suggested about participation of the alpha-range in neurophysiological mechanisms of directed attention.     

Human cardiac myosin heavy chain genes and their linkage in the genome.

Human myosin heavy chains are encoded by a multigene family consisting of at least 10 members. A gene-specific oligonucleotide has been used to isolate the human beta myosin heavy chain gene from a group of twelve nonoverlapping genomic clones. We have shown that this gene (which is expressed in both cardiac and skeletal muscle) is located 3.6kb upstream of the alpha cardiac myosin gene. We find that DNA sequences located upstream of rat and human alpha cardiac myosin heavy chain genes are very homologous over a 300bp region. Analogous regions of two other myosin genes expressed in different muscles (cardiac and skeletal) show no such homology to each other. While a human skeletal muscle myosin heavy chain gene cluster is located on chromosome 17, we show that the beta and alpha human cardiac myosin heavy chain genes are located on chromosome 14.     

Human tissue kallikreins as promiscuous modulators of homeostatic skin barrier functions

Human tissue kallikreins (KLKs) are the largest family of secreted serine protease endopeptidases encoded by 15 genes clustered on chromosome 19q13.4. Multiple KLK enzymes are co-localized in the upper stratum granulosum and stratum corneum of human epidermis, and in associated appendages such as hair follicle epithelia and sweat glands. Until recently, kallikrein proteolytic activity in the skin was exclusively attributed to KLK5 and KLK7. However, wider cutaneous roles of kallikreins became evident in recent years as the proposal of KLK proteolytic activation cascades emerged. We postulate that these proteolytic enzymes may serve as promiscuous mediators of different skin barrier functions, since they are capable of proteolysing different substrates that govern skin desquamation, antimicrobial defense, and lipid permeability. Growing evidence now attests to potential kallikrein involvement in skin inflammation, pigmentation, and tumor suppression via their ability to target proteinase-activated receptor signaling pathways. Current knowledge on kallikrein roles in skin physiology and pathobiology is described in this review.     

Regulation of sinus cardiac rhythm during different states of attention in full-term and preterm 5-month-old infants

Parasympathetic heart rate regulation was studied in full-term (FT) and very preterm (VPT) infants at the corrected age of 5 months during endogenous and exogenous sustained attention. Cardiac interval duration and the respiratory sinus arrhythmia (RSA) were used as indices of parasympathetic regulation of heart activity during infants’ sustained attention to a new visual stimulus (exogenous attention) and anticipatory attention to repeatedly appearing and disappearing stimuli in the visual expectation paradigm (endogenous attention). The psychomotor development and behavior regulation were assessed using the Bayley Scales of Infant Development, and the clinical risk was scored on the Ballard scale. A shift of attention state affected the RSA only in the FT infants. The endogenous attention was associated with a relatively high RSA level, with the higher RSA levels being significantly correlated with the Bayley Behavior Rating Scale scores. At the age of 5 months, the degree of clinical risk in the VPT infants was not correlated with specific features of parasympathetic regulation. The results are discussed in terms of the concepts of physiological mechanisms of exogenous and endogenous attention in infants. The central regulation of the autonomic functions during a shift of attention state is less efficient in healthy VPT infants as compared to their FT peers. The RSA reactivity can be a more sensitive indicator of CNS regulatory disorders than the standard indices of clinical risk.     

Suppression of gamma EEG activity as an index of a spreading depression wave in the neocortex of a waking rabbit

A spreading depression (SD) can spontaneously develop in seizures, attacks of migraine, vascular disorders and other pathological states of the brain. However, problems in technique of recording the DC-potential in the neocortex of humans and waking animals substantially restrict the possibilities of studying functional consequences of the SD. In this article, the EEG pattern was studied in detail at the moment of the SD development. Specific features were revealed, which make it possible to detect the SD without recording shifts of the DC-potential. At the moment of the SD arrival, the interhemispheric balance drastically disturbs because of a strong decrease in the high-frequency activity. By the time indices, the course of the suppression of the gammal and gamma2 EEG frequencies is the most reliable symptom of the SD wave development. The EEG spectral power in the delta band increases with a certain delay in reference to the deep depression of the high-frequency activity and is, in essence, an SD aftereffect. The found EEG signs of an SD wave can substantially simplify the identification of this phenomenon both in experiment and clinical conditions in certain pathological states of the brain.     

EEG and behavioral changes in a hyperkinetic child concurrent with training of the sensorimotor rhythm (SMR)

Reduced seizure incidence coupled with voluntary motor inhibition accompanied conditioned increases in the sensorimotor rhythm(SMR), a 12–14 Hz rhythm appearing over rolandic cortex. Although SMR biofeedback training has been successfully applied to various forms of epilepsy in humans, its potential use in decreasing hyperactivity has been limited to a few cases in which a seizure history was also a significant feature. The present study represents a first attempt to explore the technique's applicability to the problem of hyperkinesis independent of the epilepsy issue. The results of several months of EEG biofeedback training in a hyperkinetic child tend to corroborate and extend previous findings. Feedback presentations for SMR were contingent on the production of 12–14-Hz activity in the absence of 4–7-Hz slow-wave activity. A substantial increase in SMR occurred with progressive SMR training and was associated with enhanced motor inhibition, as gauged by laboratory measures of muscular tone(chin EMG) and by a global behavioral assessment in the classroom. Opposite trends in motor inhibition occurred when the training procedure was reversed and feedback presentations were contingent on the production of 4–7 Hz in the absence of 12–14-Hz activity. Although the preliminary nature of these results is stressed, the subject population has recently been increased to establish the validity and generality of the findings and will include the use of SMR biofeedback training after medication has been withdrawn.This research was a segment of the junior author's dissertation research.     

Auditory competence of the newborn infant with regard to specific and non-specific rhythms

This study is based on the analysis of modifications in the heart-rate of newborn infants (n = 12) hearing heartbeats at 72 and 120 bpm and metronome beats at 45, 72 and 120 bpm. The results show a selective discrimination of these acoustic stimulations by the infant.     

Spectral analysis of the cardiac rhythm of fishes

Spectral analysis of the rhythmograms in the cod Gadus morhua callarias, plaice Pleuronectes platessa, herring Clupea harengus membras and trout Salmo gairdneri revealed complex wave structure of their cardiac rhythm. In all the species investigated, slow (0.01-0.06 Hz), intermediate (0.06-0.25 Hz) and fast (0.25-0.5 Hz) waves were recorded. It is suggested that the wave structure of cardiac rhythm reflects rather complicated relationships between functional systems regulating cardiac activity.     

Operant conditioning of EEG rhythms and ritalin in the treatment of hyperkinesis

Enhanced voluntary motor inhibition regularly accompanies conditioned increases in the sensorimotor rhythm (SMR), a 12--14-Hz Rolandic EEG rhythm in cats.A similar rhythm, presumably SMR, has also been identified in the human EEG. The clinical effectiveness of SMR operant conditioning has been claimed for epilepsy, insomnia, and hyperkinesis concurrent with seizure disorders. The present report attempts to follow up and replicate preliminary findings that suggested the technique's successful application to hyperkinesis uncomplicated by a history of epilepsy. SMR was defined as 12--14-Hz EEG activity in the absence of high-voltage slow-wave activity between 4 and 7 Hz. Anticipated treatment effects were indexed by systematic behavioral assessments of undirected motor activity and short attention span in the classroom. EEG and behavioral indices were monitored in four hyperkinetic children under the following six conditions: (1) No Drug, (2) Drug Only, (3) Drug and SMR Training I, (4) Drug and SMR Reversal Training, (5) Drug and SMR Training II, (6) No Drug and SMR Training. All hyperkinetic subjects were maintained on a constant drug regimen throughout the phases employing chemotherapy. Contingent increases and decreases in SMR occurred in three of four training subjects and were associated with similar changes in classroom assessments of motor inactivity. Combining medication and SMR training resulted in substantial improvements that exceeded the effects of drugs alone and were sustained with SMR training after medication was withdrawn. In contrast, these physiological and behavioral changes were absent in one highly distractible subject who failed to acquire the SMR task. Finally, pretraining levels of SMR accurately reflected both the seve-ity of original motor deficits and the susceptibility of hyperkinetic subjects to both treatments. Although the procedure clearly reduced hyperkinetic behavior, a salient, specific therapeutic factor could not be identified due to the dual EEG contingency imposed combined with associated changes in EMG. Despite these and other qualifying factors, the findings suggested the prognostic and diagnostic value of the SMR in the disorder when overactivity rather than distractibility is the predominant behavioral deficit.