Hypnotizability and response to EMG relaxation training

This study examines the relationship between Spiegel's Hypnotic Induction profile (HIP) and ability to perform EMG relaxation under conditions of self-induced and audio-assisted biofeedback training. One hundred women volunteered for screening with Spiegel's test for hypnotizability. Thirty students were then selected from the top, middle, and bottom of the HIP scoring distribution for EMG biofeedback training in relaxation. Three treatment trials included baseline, EMG biofeedback with self-induced relaxation, and EMG biofeedback with audio relaxation instructions. Contrary to predictions, high HIPs were not significantly different from low HIPs on any of the treatment measures, although all students showed a training effect. The middle HIPs demonstrated significantly higher levels of EMG activity than the extreme groups.     

Association between translation efficiency and horizontal gene transfer within microbial communities

Horizontal gene transfer (HGT) is a major force in microbial evolution. Previous studies have suggested that a variety of factors, including restricted recombination and toxicity of foreign gene products, may act as barriers to the successful integration of horizontally transferred genes. This study identifies an additional central barrier to HGT-the lack of co-adaptation between the codon usage of the transferred gene and the tRNA pool of the recipient organism. Analyzing the genomic sequences of more than 190 microorganisms and the HGT events that have occurred between them, we show that the number of genes that were horizontally transferred between organisms is positively correlated with the similarity between their tRNA pools. Those genes that are better adapted to the tRNA pools of the target genomes tend to undergo more frequent HGT. At the community (or environment) level, organisms that share a common ecological niche tend to have similar tRNA pools. These results remain significant after controlling for diverse ecological and evolutionary parameters. Our analysis demonstrates that there are bi-directional associations between the similarity in the tRNA pools of organisms and the number of HGT events occurring between them. Similar tRNA pools between a donor and a host tend to increase the probability that a horizontally acquired gene will become fixed in its new genome. Our results also suggest that frequent HGT may be a homogenizing force that increases the similarity in the tRNA pools of organisms within the same community.     

Age-related changes in postural responses to backward platform translation

The aim of the study was to investigate age-related changes in postural responses to platform translation with 3 various velocities. We focused on the influence of linear velocity using the smoothed profile of platform acceleration (till 100 cm.s(-2)). Eleven healthy young (20-31 years) and eleven healthy elderly (65-76 years) subjects were examined. The subjects stood on the force platform with their eyes closed. Each trial (lasting for 8 sec) with different velocity (10, 15, 20 cm.s(-1)) of 20 cm backward platform translation was repeated 4 times. We have recorded displacements of the centre of pressure (CoP) and the EMG activity of gastrocnemius muscle (GS) and tibialis anterior muscle (TA). The results showed increased maximal values of CoP responses to the platform translation. There was also observed a scaling delay of CoP responses to platform translation with different velocities in elderly. The EMG activity of GS muscle during backward platform translation was of about similar shape in both groups during the slowest platform velocity, but it increased depending on rising velocity. EMG activity of TA was not related to the platform velocity. Early parts of postural responses showed significant co-activation of TA and GS muscles of elderly. It is likely that elderly increased body stiffening in order to help their further balance control.     

P-ANCA vasculitic neuropathy with 12-year latency between onset of neuropathy and systemic symptoms

Background  

The differential diagnosis of chronic progressive multifocal asymmetric neuropathies is challenging. Vasculitic neuropathies, multifocal forms of chronic inflammatory demyelinating polyneuropathy, multifocal motor neuropathies, and asymmetric lower motor neuron disorders are important considerations.     

Bilateral neural transections at the level of mesencephalon increase food intake and reduce latency to onset of feeding in response to neuropeptide Y

Administration of neuropeptide Y (NPY) into the IIIrd ventricle of the rat brain induces robust ingestive behavior with a latency to onset of feeding (LOF) ranging from 12 to 20 min. Since substantial amounts of NPY found in hypothalamic sites that mediate the control of feeding behavior originate from the brain stem, we studied the effects of NPY on LOF and food intake in male and female rats after bilateral severing of brain stem NPY input to the hypothalamus at the level of the mesencephalon. NPY in doses of 117 pmol significantly increased food intake and decreased LOF in both male and female transected rats. Higher doses of 470 pmol NPY decreased only the LOF in transected rats as compared to sham control rats. Additionally, 117 pmol NPY in transected rats elicited food consumption equivalent to that produced by 470 pmol NPY in control rats. These studies show that decreases in NPY levels found in the paraventricular nucleus and neighboring hypothalamic sites as a result of these neural transections may render rats hyperresponsive to NPY, presumably due to denervation-induced hypersensitivity in these sites.     

Kinematic and EMG analysis of horizontal bimanual climbing in humans

Climbing is an increasingly popular recreational and competitive behavior, engaged in a variety of environments and styles. However, injury rates are high in climbing populations, especially in the upper extremity and shoulder. Despite likely arising from an arboreal, climbing ancestor and being closely related to primates that are highly proficient climbers, the modern human shoulder has devolved a capacity for climbing. Limited biomechanical research exists on manual climbing performance. This study assessed kinematic and muscular demands during a bimanual climbing task that mimicked previous work on climbing primates. Thirty participants were recruited – 15 experienced and 15 inexperienced climbers. Motion capture and electromyography (EMG) measured elbow, thoracohumeral and trunk angles, and activity of twelve shoulder muscles, respectively, of the right-side while participants traversed across a horizontal climbing apparatus. Statistical parametric mapping was used to detect differences between groups in kinematics and muscle activity. Experienced climbers presented different joint motions that more closely mimicked the kinematics of climbing primates, including more elbow flexion (p = 0.0045) and internal rotation (p = 0.021), and less thoracohumeral elevation (p = 0.046). Similarly, like climbing primates, experienced climbers generally activated the shoulder musculature at a lower percentage of maximum, particularly during the exchange from support to swing and swing to support phase. However, high muscle activity was recorded in all muscles in both participant groups. Climbing experience coincided with a positive training effect, but not enough to overcome the high muscular workload of bimanual climbing. Owing to the evolved primary usage of the upper extremity for low-force, below shoulder-height tasks, bimanual climbing may induce high risk of fatigue-related musculoskeletal disorders.     

Correlation between ventilation and EEG-defined arousal during sleep onset in young subjects

Trinder, John, John A. Van Beveren, Philip Smith, JanKleiman, and Amanda Kay. Correlation between ventilation and EEG-defined arousal during sleep onset in young subjects.J. Appl. Physiol. 83(6):2005-2011, 1997.In studies of elderly individuals, ventilationand EEG-defined arousal have been shown to vary periodically andsynchronously. Such results have been interpreted as indicating theprimacy of sleep/wake state in causing ventilatory instability duringsleep onset. However, because the elderly individuals studied wereperiodic breathers, the results do not unequivocally support thisconclusion. In this study the relationship between ventilation andEEG-defined arousal was assessed in a group of 21 young, healthy men inwhom ventilatory instability during sleep onset was not periodic.Ventilation and EEG(O₁-A₂)recordings were collected, and the longest uncontaminated periods fromearly and late in sleep onset were selected for subsequent analysis.The 84 time series (21 subjects, 2 variables, and 2 occasions in sleeponset) were subjected to spectral analysis to identify periodicity, and the relationship between the two variables was determined bycross-correlational methods. The results indicated that the time serieswere nonperiodic, yet significant correlations were observed betweenthe two variables. The data support the view that during sleep onsetventilatory instability is driven primarily by variations in sleep/wakearousal level.

     

Correlation between precolonization of trigeminal ganglia by attenuated strains of pseudorabies virus and resistance to wild-type virus latency.

We compared the levels of latent pseudorabies virus (PRV) DNA in trigeminal ganglia (TG) of pigs after intranasal inoculation of different PRV strains by using quantitative DNA PCR. The extent of colonization attained in each case varied significantly according to the type of strain and inoculum dose, wild-type (WT) PRV being the most efficient strain in colonizing TG. When groups of pigs representing different levels of precolonization of TG with an attenuated PRV strain were challenged with WT PRV, it became evident that there is a statistically significant inverse correlation between the extent of precolonization attained by an attenuated PRV strain in TG and the level of establishment of latency by superinfecting WT PRV. The protection against WT PRV latency did not correlate with the extent of WT PRV replication at the portal of entry.     

Distinct response of yeast ribosomes to a miscoding event during translation

Numerous mechanisms have evolved to control the accuracy of translation, including a recently discovered retrospective quality control mechanism in bacteria. This quality control mechanism is sensitive to perturbations in the codon:anticodon interaction in the P site of the ribosome that trigger a dramatic loss of fidelity in subsequent tRNA and release factor selection events in the A site. These events ultimately lead to premature termination of translation in response to an initial miscoding error. In this work, we extend our investigations of this mechanism to an in vitro reconstituted Saccharomyces cerevisiae translation system. We report that yeast ribosomes do not respond to mismatches in the P site by loss of fidelity in subsequent substrate recognition events. We conclude that retrospective editing, as initially characterized in Escherichia coli, does not occur in S. cerevisiae. These results highlight potential mechanistic differences in the functional core of highly conserved ribosomes.     

Relation between object properties and EMG during reaching to grasp

In order to stably grasp an object with an artificial hand, a priori knowledge of the object’s properties is a major advantage, especially to ensure subsequent manipulation of the object held by the hand. This is also true for hand prostheses: pre-shaping of the hand while approaching the object, similar to able-bodied, allows the wearer for a much faster and more intuitive way of handling and grasping an object. For hand prostheses, it would be advantageous to obtain this information about object properties from a surface electromyography (sEMG) signal, which is already present and used to control the active prosthetic hand.We describe experiments in which human subjects grasp different objects at different positions while their muscular activity is recorded through eight sEMG electrodes placed on the forearm. Results show that sEMG data, gathered before the hand is in contact with the object, can be used to obtain relevant information on object properties such as size and weight.     

Correlation between far-red absorbing phytochrome and response in phytochrome-mediated anthocyanin synthesis

Abstract Mustard seedlings were light treated at 24 h after sowing (25°C) to induce phytochrome-mediated anthocyanin synthesis in cotyledons and hypocotylar hook. All light treatments were performed within the range of the reciprocity law. The in situ photoconversion kinetics of phytochrome (P_r→ P_fr) were measured under the same light treatment. It was found that between 0.4 and 1.0 relative P_fr level the amount of anthocyanin extracted from the organs at 52 h after sowing was linearily correlated with the amount of P_fr produced at 24 h in cotyledons and hypocotylar hook. It is concluded that an explanation of the fluence response function for red light mediated anthocyanin synthesis in the mustard seedling does not require the concept of active vs. bulk phytochrome.     

Correlation between SERT polymorphisms and Venlafaxine response in major depression patients

Major depression (MD) has a complex multifactorial aetiology with genetic and environmental factors contributing to this disorder. As with all antidepressant treatments, there is variability in drug response because of heredity, and this leads us to focus on the genetic polymorphism of the drug’s metabolising transporter genes. The serotonin transporter (5-HTT) gene is a particularly important candidate for genetic involvement in MD disorders owing to its key role in the regulation of serotonergic transmission and is therefore considered an interesting candidate in the mechanism of antidepressant drugs. Here, we studied the associations between genetic polymorphisms in two regions of the 5-HTT gene (5-HTTLPR and VNTR) to understand venlafaxine response. Venlafaxine was found to be effective in MD patients based on their HAM-D and CGI scores (p<0.05). Although the results did not yield a significant difference between the frequencies of the SS, LS, LL, 9/9, 10/10, 12/12 and 10/12 genotypes and venlafaxine response, venlafaxine dose was increased in patients with Stin2.12 and S alleles. These alleles might have a predisposition to mood disorders. Further studies with more patients are required to confirm this clinical association.     

Aromatization of androgens into estrogens reduces response latency to a noxious thermal stimulus in male quail

We recently demonstrated the presence of estrogen synthase (aromatase) and of estrogen receptors in the dorsal horn (laminae I-II) throughout the rostrocaudal extent of the spinal cord in male and female Japanese quail. The spinal laminae I-II receive and process abundant sensory information elicited, among others, by acute noxious stimulation of the skin and resulting in rapid, reflex-like withdrawal behavior. In the present study, we demonstrate that systemic treatment with estradiol or testosterone markedly decreases the latency of the foot withdrawal in the hot water test. A simultaneous treatment with an aromatase inhibitor blocks the effects of testosterone demonstrating, hence, that they are mediated by a conversion of testosterone into an estrogen by aromatase. Furthermore, the testosterone- or estradiol-induced decrease in foot withdrawal latency is blocked by a treatment with the estradiol receptor antagonist, tamoxifen, indicating that the effects are largely mediated by the interaction of estradiol with estrogen receptors. Together, these data suggest that sex steroids modulate sensitivity to noxious stimuli possibly by a direct action at the level of the dorsal horn of the spinal cord.     

Diel horizontal migration and swarm formation in Daphnia in response to Chaoborus

Dense swarms of Daphnia longispina (up to 4000 animals l^–1) were recorded along the littoral zone in a lake where Chaoborus flavicans is considered the main predator. D. longispina coexisted with D. pulex, but there were no D. pulex in the littoral swarms. Swarms were less dense at night (about 1/10 the density), and D. longispina exhibited diel horizontal migrations by aggregating in the littoral during the day and spreading out at night. Laboratory experiments showed that Chaoborus capture efficiency on juvenile daphnids was higher in the light compared to darkness, and that Daphnia exhibited a behavioural response to water that had previously contained Chaoborus. We conclude that predation from Chaoborus can be an important factor affecting the distribution patterns of Daphnia observed in this lake. The behavioural experiments indicated that this influence might be partly mediated by chemical agents.     

Parametric inference of neuronal response latency in presence of a background signal

Neurons are commonly characterized by spontaneous generation of action potentials (spikes), which appear without any apparent or controlled stimulation. When a stimulus is applied, the spontaneous firing may prevail and hamper identification of the effect of the stimulus. Therefore, for any rigorous analysis of evoked neuronal activity, the presence of spontaneous firing has to be taken into account. If the background signal is ignored, however small it is compared to the response activity, and however large is the delay, estimation of the response latency will be wrong, and the error will persist even when sample size is increasing. The first question is: what is the response latency to the stimulus? Answering this question becomes even more difficult if the latency is of a complex nature, for example composed of a physically implied deterministic part and a stochastic part. This scenario is considered here, where the response time is a sum of two components; the delay and the relative latency. Parametric estimators for the time delay and the response latency are derived. These estimators are evaluated on simulated data and their properties are discussed. Finally, we show that the mean of the response latency is always satisfactorily estimated, even assuming a wrong distribution for the response latency.     

Correlation between the adaptive response and individual sensitivity to monoepoxybutene in in vitro experiments on human lymphocytes

Individual variations in the susceptibility to mutagenic/carcinogenic chemicals depend on the activity of xenobiotic metabolizing enzymes and on DNA- and chromosome-damage repair systems. Monoepoxybutene (MEB) is a genotoxic metabolite of 1,3-butadiene (BD), which has been classified as a probable carcinogen in humans. The purpose of the present study was to investigate by in vitro experiments on human whole blood lymphocytes (WBL), whether an individual sensitivity to MEB correlates with the adaptive response to the tested agent. In the analyzed group, 8.3% of blood donors were relatively sensitive to MEB. The comparison of SCE induction in cultures pretreated and not pretreated with an adaptive dose (AD) of MEB showed, that there was an adaptive response to MEB. The adaptive response in the group of relatively sensitive donors was similar to that of the relatively resistant ones. This result suggests that individual sensitivity to the tested agent and adaptive response depend on different biological mechanisms.     

Influence of the cardiac phase on the latency of a motor response to a visual stimulus in the blowfly

The main feature of heart activity in the blowfly, Calliphora vomitoria, is the regular alternation of phases of forward and backward beating. It is known that forward beats are inhibited by sensory stimulation and locomotor activity. In the present study it is shown that the latency of a motor response to a moving visual stimulus is significantly longer when the releasing stimulus is applied in the course of forward beating (0.90 ± 0.07 sec) than during backward beating (0.70 ± 0.06 sec). A facilitatory influence of backward beating of the heart on motor activity is thus demonstrated. This finding is discussed with reference to the biological significance of heart-beat reversal in insects and a possible role for sensory-induced cardiac responses as preparatory for motor behaviour.