Mal de débarquement syndrome.

Mal de débarquement syndrome (MdDS) is typified by a prolonged rocking sensation - for a month or longer - that begins immediately following a lengthy exposure to motion. The provoking motion is usually a sea voyage. About 80% of MdDS sufferers are women, and most of them are middle-aged. MdDS patients are troubled by more migraine headaches than controls. Unlike dizziness caused by vestibular disorders or motion sickness, the symptoms of MdDS usually improve with re-exposure to motion. The long duration of symptoms - a month or more - distinguishes MdDS from land-sickness. Treatment of MdDS with common vestibular suppressants is nearly always ineffective. Benzodiazepines can be helpful, but their usefulness is limited by the potential for addiction. Studies are ongoing regarding treatment with visual habituation and transcranial magnetic stimulation.

Complete genome sequence of the animal pathogen Listeria ivanovii, which provides insights into host specificities and evolution of the genus Listeria.

We report the complete and annotated genome sequence of the animal pathogen Listeria ivanovii subsp. ivanovii strain PAM 55 (serotype 5), isolated in 1997 in Spain from an outbreak of abortion in sheep. The sequence and its analysis are available at an interactive genome browser at the Institut Pasteur (http://genolist.pasteur.fr/LivaList/).

Genotypic characterization of Listeria monocytogenes isolated from humans in India.

Listeria monocytogenes is a foodborne pathogen associated with severe diseases in humans and animals. The genotypic analysis of 17 L. monocytogenes isolates recovered from humans in India during 2006-2009 using multiplex serotyping PCR allowing serovar predictions, conventional serology and by pulsed field gel electrophoresis (PFGE) is presented. The isolates were recovered from patients exhibiting various clinical conditions. A multiplex-PCR based serotyping assay revealed 88·24% (15/17) of the strains belonging to the serovar group 4b, 4d, 4e and 11·76% (2/17) to the serovar group 1/2b, 3b. Conventional serology indicated that 13 (76·47%) L. monocytogenes isolates to be of serotype 4b, 2 (11·76%) serotype 4d, and 2 (11·76%) serotype 1/2b. Ten ApaI and nine AscI pulsotypes were recognized among the 17 human isolates. PFGE analysis allowed discrimination among isolates of the same serotype and among isolates from the same sampling areas or those isolated from different areas. Thus, PFGE together with multiplex-PCR serotyping allows rapid discrimination of L. monocytogenes strains. In addition, the predominance of L. monocytogenes serotype 4b is of concern, as this serotype has been most frequently associated with human listeriosis outbreaks.

Multiple ST clonal complexes, with a predominance of ST131, of Escherichia coli harbouring blaCTX-M-15 in a tertiary hospital in Tanzania.

The molecular epidemiology of 32 non-duplicate, CTX-M-15 extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains, isolated from clinical samples, was investigated. Multilocus sequence typing revealed multiple sequence type clonal complexes: ST131 (12), ST405 (4), ST638 (3), ST38 (2), ST827 (2), ST224 (1), ST648 (1), ST46 (1) and two new sequence type clonal complexes (1845 and 1848) in 22 pulsed field gel electrophoresis clusters. The bla(CTX-M-15) gene was located on conjugative IncF plasmids. This is the first report of the worldwide emerging clonal complex ST131 linked to bla(CTX-M-15) in Tanzania and demonstrates the need for constant surveillance in developing countries to prevent the spread of these multiresistant isolates.

Kinship affects innate responses to a predator in bluegill Lepomis macrochirus larvae.

Naïve kin groups and mixed-family groups of bluegill Lepomis macrochirus larvae were exposed to a novel predator cue. The larvae responded by increasing shoal cohesiveness in kin groups but not in mixed-family groups; moreover, larvae sired by males of the 'cuckolder' life history tended to have an enhanced ability to respond to direct cues of kinship v. larvae sired by males of the 'parental' life history, which instead appeared to respond to cues of life history rather than relatedness per se. The increased shoal cohesion among related individuals probably confers a survival benefit and indicates that the antipredatory shoaling response is innate in L. macrochirus.

A voice-activated integrated development environment for manually disabled programmers.

PURPOSE: The paper presents the design and implementation of voice-based interface to support two types of application development activities (coding, and visual GUI design) by manually disabled programmers. METHOD: Prototype programs were implemented, and tests were performed for both proposed voice-based interface models. RESULTS: The interface design concepts, and the results and lessons learned of the usability studies are discussed. CONCLUSIONS: The usability studies indicated that the interface models were sound, although the voice recognition aspects left something to be desired.

Hidden pathogens uncovered: metagenomic analysis of urinary tract infections.

Urinary tract infections (UTIs) are the most common kidney and urologic diseases in industrial nations and are usually caused through faecal contamination of the urinary tract. In this study, we have examined 1449 urine specimens both by culture and by PCR. The majority of UTIs examined were caused by Escherichia coli (35.15%), followed by miscellaneous bacteria (23.03%), and by Enterococcus faecalis (19.39%). A large fraction of fastidious and anaerobic bacteria (22.43%) was not detected under culture conditions but only by using PCR. This group of bacteria evade the standard culture conditions used in routine diagnostic laboratories examining urine specimens. The molecular approach used broad-range 16S rDNA PCR, denaturing high-performance liquid chromatography analysis, sequencing, and bioinformatic analysis to uncover these 'hidden' pathogens and is recommended in particular when examining leukocyte esterase-positive and culture-negative urinary tract specimens.

GECO--linear visualization for comparative genomics.

UNLABELLED: In order to understand and interpret phylogenetic and functional relationships between multiple prokaryotic species, qualitative and quantitative data must be correlated and displayed. GECO allows linear visualization of multiple genomes using a client/server based approach by dynamically creating .png- or .pdf-formatted images. It is able to display ortholog relations calculated using BLASTCLUST by color coding ortholog representations. Irregularities on the genomic level can be identified by anomalous G/C composition. Thus, this software will enable researchers to detect horizontally transferred genes, pseudogenes and insertions/deletions in related microbial genomes. AVAILABILITY: http://bioinfo.mikrobio.med.uni-giessen.de/geco2/GecoMainServlet

Augur--a computational pipeline for whole genome microbial surface protein prediction and classification.

UNLABELLED: The analysis of protein function is a challenge and a major bottleneck towards well-annotated and analysed microbial genomes. In particular, bacterial surface proteins present an opportunity for pharmacological intervention and vaccine development. We present Augur, an automatic prediction pipeline that integrates major surface prediction algorithms and enables comparative analysis, classification and visualization for gram-positive bacteria on a genomic scale. AVAILABILITY: http://bioinfo.mikrobio.med.uni-giessen.de/augur

Perturbation parameters associated with nonlinear responses of the head at small amplitudes.

The head-neck system has multiple degrees of freedom in both its control and response characteristics, but is often modeled as a single joint mechanical system. In this study, we have attempted to quantify the perturbation parameters that would elicit nonlinear responses in a single degree-of-freedom neuromechanical system at small amplitudes and velocities of perturbation. Twelve healthy young adults seated on a linear sled randomly received anterior-posterior sinusoidal translations with +/-15 mm and +/-25 mm peak displacements at 0.81, 1.76, and 2.25 Hz. Head angular velocity and angular position data were examined using a nonlinear phase-plane analysis. Poincare sections of the phase plane were computed and Lyapunov exponents calculated to measure divergence (chaotic behavior) or convergence (stable behavior) of system dynamics. Variability of head angular position and velocity across the entire phase plot was compared to that of the Poincare sections to quantify spatial-temporal irregularity. Multiple equilibrium points and positive Lyapunov exponents revealed chaotic behavior at 0.81 Hz at both amplitudes whereas responses at 1.76 and 2.25 Hz exhibited periodic oscillations, clustered phase points, and negative Lyapunov exponents. However, intersubject variability increased at the lowest frequency and a few subjects presented chaotic behavior at all frequencies. An inverted pendulum with position and velocity threshold nonlinearity was adopted as a simplistic model of the head and neck. Simulations with the model resulted in features similar to those observed in the experimental data. Our principal finding was that increasing the perturbation amplitude had a stabilizing effect on the behavior across frequencies. Nonlinear behaviors observed at the lowest stimulus frequency might be attributed to fluctuations in control between the multiple sensory inputs. Although this study has not conclusively pointed toward any single mechanism as responsible for the responses observed, it has revealed clear directions for further investigation. To examine if changing the sensory modalities would elicit a significant change in the nonlinear behaviors observed here, further experiments that target a patient population with some sort of sensory deficit are warranted.

[The pharmacology of vestibular disorders]. / Farmacología de las alteraciones vestibulares.

INTRODUCTION: In recent years, significant advances have been made in the physiology and the pharmacology of vestibular disorders. It is now possible to elaborate an approximation of the mechanisms of action of the drugs used in the symptomatic treatment of vertigo. DEVELOPMENT: These drugs usually have a number of different pharmacological actions and overlapping effects. They can modify the intensity of the symptoms (e.g. vestibular suppressants) or prevent recurrences (e.g. calcium blockers in the case of vestibular migraine). Most of the drugs used for the acute treatment of vertigo can have a negative effect on the central compensation mechanisms. Vestibular rehabilitation exercises and certain drugs can speed up compensation. Choice of medication and the method of administration depend on the severity of the clinical symptoms, the pattern of temporal evolution, the underlying vestibular disease, the associated clinical conditions and the profile of the collateral effects of the drugs utilised. CONCLUSIONS: Vestibular suppressants and antiemetic drugs are still the basis of the acute treatment of vertigo.

[Neck vibration: usefulness in neurotology]. / Vibración cervical: utilidad neurootológica.

INTRODUCTION: Recently, mechanical vibration on the neck has begun to be used to improve diagnostic sensitivity in patients who have vestibular disorders. METHOD: We review results of studies of this stimulus in normal subjects and patients with vestibular lesions: the ocular responses, changes in the subjective straight ahead, and postural changes generated by the neck vibration. CONCLUSION: Although the underlying mechanism for the responses to neck vibration remains uncertain, it is an excellent addition to the neurotologic exam since it allows us demonstrate vestibular deficit with greater sensitivity than other maneuvers. As vibration is easy to apply it can be useful for screening in patients who complain of dizziness.

Effects of predictive mechanisms on head stability during forward trunk perturbation.

While much is known about reflex and mechanical contributions to the control of head stability, little is known about predictive control. The goal of this experiment was to determine the contribution of predictive mechanisms to head stability in space, in the pitch plane, during forward trunk perturbations. Eleven standing healthy subjects had their trunk pulled forward by a load-pulley apparatus. The perturbation was either self-triggered or imposed (triggered by the experimenter). Subjects were exposed to two loads: 2% and 4% of their body weight. The contributions of torques acting on the head-neck system were inferred from head and trunk kinematics, neck muscle EMG, and the torques acting on the head, which were computed using inverse dynamics. The results showed that both the head and trunk moved less during the self-triggered than imposed condition during both loads for most of the participants. There was no evidence of predictive neck countertorque or increased neck muscle co-contraction during the self-triggered condition. These findings suggest that most of the subjects improved head stability in the self-triggered condition by reducing trunk motion and the associated interactive torque that perturbed the head.

Modeling head tracking of visual targets.

Control of the head involves somatosensory, vestibular, and visual feedback. The dynamics of these three feedback systems must be identified in order to gain a greater understanding of the head control system. We have completed one step in the development of a head control model by identifying the dynamics of the visual feedback system. A mathematical model of human head tracking of visual targets in the horizontal plane was fit to experimental data from seven subjects performing a visual head tracking task. The model incorporates components based on the underlying physiology of the head control system. Using optimization methods, we were able to identify neural processing delay, visual control gain, and neck viscosity parameters in each experimental subject.

Dynamic and kinematic strategies for head movement control.

This paper describes our analysis of the complex head-neck system using a combination of experimental and modeling approaches. Dynamical analysis of head movements and EMG activation elicited by perturbation of trunk position has examined functional contributions of biomechanically and neurally generated forces in lumped systems with greatly simplified kinematics. This has revealed that visual and voluntary control of neck muscles and the dynamic and static vestibulocollic and cervicocollic reflexes preferentially govern head-neck system state in different frequency domains. It also documents redundant control, which allows the system to compensate for lesions and creates a potential for substantial variability within and between subjects. Kinematic studies have indicated the existence of reciprocal and co-contraction strategies for voluntary force generation, of a vestibulocollic strategy for stabilizing the head during body perturbations and of at least two strategies for voluntary head tracking. Each strategy appears to be executed by a specific muscle synergy that is presumably optimized to efficiently meet the demands of the task.

Comparative genomics of Listeria species.

Listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. We present and compare the genome sequences of L. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, L. innocua (3,011,209 base pairs). We found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. The presence of 270 L. monocytogenes and 149 L. innocua strain-specific genes (clustered in 100 and 63 islets, respectively) suggests that virulence in Listeria results from multiple gene acquisition and deletion events.

Bioinformatics in medical practice: what is necessary for a hospital?

Building bioinformatic facilities for a university hospital is pretty similar to using standardized building blocks to construct a house. Starting with the intention to built a dwelling house, a factory or just a shelter the architect draws a construction plan and determines the material to be used. In general, the building is then constructed by the workmen following exactly the plan. However, for particular reasons, minor alterations may be needed to improve the construction of the building. Here we use the metaphor of constructing a "bio-informatics building" to describe the steps needed to support the daily tasks of a university hospital medical microbiology department which uses genomic methods quite extensively for pathogen identification. Today the Giessen "bioinformatics building" is not yet complete but we have been able to lay solid foundations and erect the ground floor which is functional already. Using a combination of standard tools, internet accessible genomic databases and some own software tools we can support genome sequencing from the raw sequence to pathogen identification.

Internalins from the human pathogen Listeria monocytogenes combine three distinct folds into a contiguous internalin domain.

Listeria monocytogenes is an opportunistic, food-borne human and animal pathogen. Host cell invasion requires the action of the internalins A (InlA) and B (InlB), which are members of a family of listerial cell-surface proteins. Common to these proteins are three distinctive N-terminal domains that have been shown to direct host cell-specific invasion for InlA and InlB. Here, we present the high-resolution crystal structures of these domains present in InlB and InlH, and show that they constitute a single "internalin domain". In this internalin domain, a central LRR region is flanked contiguously by a truncated EF-hand-like cap and an immunoglobulin (Ig)-like fold. The extended beta-sheet, resulting from the distinctive fusion of the LRR and the Ig-like folds, constitutes an adaptable concave interaction surface, which we propose is responsible for the specific recognition of the host cellular binding partners during infection.