MR Imaging of the Extracranial Facial Nerve with the CISS Sequence.

BACKGROUND AND PURPOSE: MR imaging is not routinely used to image the extracranial facial nerve. The purpose of this study was to determine the extent to which this nerve can be visualized with a CISS sequence and to determine the feasibility of using that sequence for locating the nerve relative to tumor. MATERIALS AND METHODS: Thirty-two facial nerves in 16 healthy subjects and 4 facial nerves in 4 subjects with parotid gland tumors were imaged with an axial CISS sequence protocol that included 0.8-mm isotropic voxels on a 3T MR imaging system with a 64-channel head/neck coil. Four observers independently segmented the 32 healthy subject nerves. Segmentations were compared by calculating average Hausdorff distance values and Dice similarity coefficients. RESULTS: The primary bifurcation of the extracranial facial nerve into the superior temporofacial and inferior cervicofacial trunks was visible on all 128 segmentations. The mean of the average Hausdorff distances was 1.2 mm (range, 0.3-4.6 mm). Dice coefficients ranged from 0.40 to 0.82. The relative position of the facial nerve to the tumor could be inferred in all 4 tumor cases. CONCLUSIONS: The facial nerve can be seen on CISS images from the stylomastoid foramen to the temporofacial and cervicofacial trunks, proximal to the parotid plexus. Use of a CISS protocol is feasible in the clinical setting to determine the location of the facial nerve relative to tumor.

Disentangling the genetic effects of refugial isolation and range expansion in a trans-continentally distributed species.

In wide-ranging taxa with historically dynamic ranges, past allopatric isolation and range expansion can both influence the current structure of genetic diversity. Considering alternate historical scenarios involving expansion from either a single refugium or from multiple refugia can be useful in differentiating the effects of isolation and expansion. Here, we examined patterns of genetic variability in the trans-continentally distributed painted turtle (Chrysemys picta). We utilized an existing phylogeographic dataset for the mitochondrial control region and generated additional data from nine populations for the mitochondrial control region (n = 302) and for eleven nuclear microsatellite loci (n = 247). We created a present-day ecological niche model (ENM) for C. picta and hindcast this model to three reconstructions of historical climate to define three potential scenarios with one, two, or three refugia. Finally, we employed spatially-explicit coalescent simulations and an approximate Bayesian computation (ABC) framework to test which scenario best fit the observed genetic data. Simulations indicated that phylogeographic and multilocus population-level sampling both could differentiate among refugial scenarios, although inferences made using mitochondrial data were less accurate when a longer coalescence time was assumed. Furthermore, all empirical genetic datasets were most consistent with expansion from a single refugium based on ABC. Our results indicate a stronger role for post-glacial range expansion, rather than isolation in allopatric refugia followed by range expansion, in structuring diversity in this species. To distinguish among complex historical scenarios, we recommend explicitly modeling the effects of range expansion and evaluating alternate refugial scenarios for wide-ranging taxa.

Interoperability and HealthGRID.

OBJECTIVES: GRID technology, with initiatives like the GGF, will have the potential to allow both competition and interoperability not only among applications and toolkits, but also among implementations of key services. The pyramid of eHealth interoperability should be achieved from standards in communication and data security, storage and processing, to the policy initiatives, including organizational protocols, financing procedures, and legal framework. The open challenges for GRID use in clinical fields illustrate the potential of the combination of grid technologies with medical routine into a wider interoperable framework. METHODS: The Telemedicine Alliance is a consortium (ESA, WHO and ITU), initiated in 2002, in building a vision for the provision of eHealth to European citizens by 2010. After a survey with more that 50 interviews of experts, interoperability was identified as the main showstopper to eHealth implementation. RESULTS: There are already several groups and organizations contributing to standardization. TM-Alliance is supporting the "e-Health Standardization Coordination Group" (eHSCG). CONCLUSIONS: It is now, in the design and development phase of GRID technology in Health, the right moment to act with the aim of achieving an interoperable and open framework. The Health area should benefit from the initiatives started at the GGF in terms of global architecture and services definitions, as well as from the security and other web services applications developed under the Internet umbrella. There is a risk that existing important results of the standardization efforts in this area are not taken up simply because they are not always known.

Dimerization partners determine the activity of the Twist bHLH protein during Drosophila mesoderm development.

The basic helix-loop-helix transcription factor Twist regulates a series of distinct cell fate decisions within the Drosophila mesodermal lineage. These twist functions are reflected in its dynamic pattern of expression, which is characterized by initial uniform expression during mesoderm induction, followed by modulated expression at high and low levels in each mesodermal segment, and finally restricted expression in adult muscle progenitors. We show two distinct partner-dependent functions for Twist that are crucial for cell fate choice. We find that Twist can form homodimers and heterodimers with the Drosophila E protein homologue, Daughterless, in vitro. Using tethered dimers to assess directly the function of these two particular dimers in vivo, we show that Twist homodimers specify mesoderm and the subsequent allocation of mesodermal cells to the somatic muscle fate. Misexpression of Twist-tethered homodimers in the ectoderm or mesoderm leads to ectopic somatic muscle formation overriding other developmental cell fates. In addition, expression of tethered Twist homodimers in embryos null for twist can rescue mesoderm induction as well as somatic muscle development. Loss of function analyses, misexpression and dosage experiments, and biochemical studies indicate that heterodimers of Twist and Daughterless repress genes required for somatic myogenesis. We propose that these two opposing roles explain how modulated Twist levels promote the allocation of cells to the somatic muscle fate during the subdivision of the mesoderm. Moreover, this work provides a paradigm for understanding how the same protein controls a sequence of events within a single lineage.

The EGL-3 proprotein convertase regulates mechanosensory responses of Caenorhabditis elegans.

Neuroactive peptides are packaged as proproteins into dense core vesicles or secretory granules, where they are cleaved at dibasic residues by copackaged proprotein convertases. We show here that the Caenorhabditis elegans egl-3 gene encodes a protein that is 57% identical to mouse proprotein convertase type 2 (PC2), and we provide evidence that this convertase regulates mechanosensory responses. Nose touch sensitivity (mediated by ASH sensory neurons) is defective in mutants lacking GLR-1 glutamate receptors (GluRs); however, mutations eliminating the egl-3 PC2 restored nose touch sensitivity to glr-1 GluR mutants. By contrast, body touch sensitivity (mediated by the touch cells) is greatly diminished in egl-3 PC2 mutants. Taken together, these results suggest that egl-3 PC2-processed peptides normally regulate the responsiveness of C. elegans to mechanical stimuli.

The effect of heliox in acute severe asthma: a randomized controlled trial.

STUDY OBJECTIVES: To evaluate the effect of heliox on airflow obstruction and dyspnea in patients with acute severe asthma. DESIGN: A prospective, randomized, controlled study. SETTING: A university hospital. PATIENTS: Twenty-three patients presenting to the emergency department with acute severe asthma were randomized to receive 70%/30% heliox or 30% oxygen. MEASUREMENTS: Peak expiratory flow (PEF), dyspnea score, heart rate, respiratory rate (RR), and BP were measured at baseline and 20, 120, 240, 360, and 480 min after starting the test gas. After baseline, the PEF was measured by using the gas that was randomized to the treatment program. RESULTS: In the first 20 min, there was a 58.4% increase in percent predicted PEF (%PEF) in the heliox group (p<0.001), whereas there was only a 10.1% increase in %PEF for the oxygen group (p>0.1). Eighty-two percent of the heliox group had >25% improvement in %PEF at 20 min, whereas only 17% of the oxygen group did (p<0.01). The next significant improvement in %PEF in the heliox group occurred at 480 min. At the end of the study in the heliox group, the PEF did not significantly (p>0.1) change immediately after the heliox was discontinued (270.6 to 264.2 L/min). In the heliox group in the first 20 min, there was a significant decrease in dyspnea score and RR (p<0.05), but there were no further significant improvements for the rest of the study. In the oxygen group, no variables significantly improved until 360 min. CONCLUSION: Heliox rapidly improves airflow obstruction and dyspnea in patients with acute severe asthma and may be useful as a therapeutic bridge until the corticosteroid effect occurs.

Inverted pyramidal neurons in chimpanzee sensorimotor cortex are revealed by immunostaining with monoclonal antibody SMI-32.

We used the monoclonal antibody SMI-32 to label pyramidal cells of sensorimotor cortex in two chimpanzees. The majority of the pyramidal cells had typical vertically oriented apical dendrites that extended towards the pial surface. A small population of pyramidal cells varied from this orientation, so that the apical dendrites were 20 degrees or more from radial, and were often inverted, extending away from the pial surface. When numbers of non-inverted and inverted pyramidal cells were compared, less than 1% were found to be inverted.

Distinct signaling pathways mediate touch and osmosensory responses in a polymodal sensory neuron.

The Caenorhabditis elegans ASH sensory neurons mediate responses to nose touch, hyperosmolarity, and volatile repellent chemicals. We show here that distinct signaling pathways mediate the responses to touch and hyperosmolarity. ASH neurons distinguish between these stimuli because habituation to nose touch has no effect on the response to high osmolarity or volatile chemicals (1-octanol). Mutations in osm-10 eliminate the response to hyperosmolarity but have no effect on responses to nose touch or to volatile repellents. OSM-10 is a novel cytosolic protein expressed in ASH and three other classes of sensory neurons. Mutations in two other osmosensory-defective genes, eos-1 and eos-2, interact genetically with osm-10. Our analysis suggests that nose touch sensitivity and osmosensation occur via distinct signaling pathways in ASH and that OSM-10 is required for osmosensory signaling.

Psycho-social training for man in space.

In preparation for the international manned space station various international and national space agencies are already participating with the Russian MIR programme with short, medium, and long term presence on the MIR station. Although selection criteria for all crew include careful psychological screening, with some effort also regarding team build-up, this has proved insufficient; moreover. little or no effort is expended in the area of psycho-social- or team training. This paper propounds the authors' thesis that, in addition to the steps already being taken, psycho-social training is essential for long-duration flight. A concrete proposal is made for such a training program, with an overview of how such a program will look like; examples of past applications are given.

Extensor hallucis longus tendon injury: an in-depth analysis and treatment protocol.

This article analyzes the controversial topic of whether or not to repair a lacerated extensor hallucis longus tendon. A literature review of extensor hallucis longus tendon injuries is presented. The authors then provide a treatment protocol for extensor hallucis tendon injuries.

Rapid-eye-movement-specific sleep-disordered breathing: a possible cause of excessive daytime sleepiness.

Some patients referred for polysomnography with complaints of excessive daytime sleepiness (EDS) and clinically suspected obstructive sleep apnea (OSA) have a respiratory disturbance index (RDI) < 10. Many would consider these patients not to have OSA. We reviewed 34 such patients to determine whether respiratory disturbances confined primarily to rapid eye movement (REM) sleep correlated with an objective criterion for EDS: a mean sleep latency (MSL) < 10 min. REM-specific events were quantified with indices calculated for REM sleep alone. Univariate linear regression showed that a REM-specific respiratory disturbance index (REM-RDI) and the transient arousal index (TAI) computed for REM sleep (REM-TAI) were associated with a low MSL (R2 = -0.35, p = 0.001; and R2 = -0.27, p = 0.01, respectively). In our subjectively sleepy patients with an overall RDI < 10, a REM-RDI > or = 15 had the highest predictive accuracy (82%) for an MSL < 10 min. Seventeen of the 34 study patients had a REM-RDI > or = 15. Their mean MSL was 8.3 +/- 0.8 min. We conclude that within a group of patients with daytime sleepiness, suspected OSA, and a normal RDI, there may be a subset who have clinically significant REM-specific sleep-disordered breathing.

Operational evaluation of the EXEMSI project. Experimental Campaign for the European Manned Space Infrastructure.

In general the EXEMSI project has proved to be very successful mission. It has demonstrated that it is indeed possible to perform a major and useful project in a short time and on a moderate budget. In addition to achieving the scientific objectives, this simulation project provided valuable experience in the training of members of chamber crew and ground control crew for their tasks. It covered all aspects of a mission from call for experiment proposals, crew selection and training, integration and testing of the facility and its equipment, to daily monitoring and managing of the mission, and finally post-isolation data collection and evaluation. These other activities were accomplished by a small team of experts in the astoundingly short time of 8 months. What was lacking in manpower, time and funds, was more than made up for by enthusiasm, expertise, team spirit, hard work and long hours well beyond the call of duty of all those involved. In addition to the specific and technological objectives reached, many lessons learned in this operation have been identified, which could help to improve future missions. The experience has shown pitfalls to be avoided in future mission, as well as points where some small increase in effort can make a considerable difference. With the prospect of long-term manned spaceflights looming in the near future and the ever increasing costs of such endeavors, the possibilities offered by running simulated missions on the ground should be seriously considered. Such simulations permit the study of scientific and operational aspects of a space mission prior to its actual implementation. A ground based simulation of an extended space mission may be run at a fraction of the cost of an in-orbit precursor mission of even one-week duration. However, careful planning of the simulation mission is required so that it may yield relevant information and useful experience. Lessons learned from the EXEMSI project should be taken into account in such planning. At the start clear goals should be formulated, that can provide clear guidelines for building up the infrastructure and defining the operational scenario. A long duration mission simulating the conditions on the Russian space station MIR could provide a valuable source of information and experience in preparing for the MIR '95 Mission.

Group dynamics training for manned spaceflight and the CAPSULS mission: prophylactic against incompatibility and its consequences?

On February 7, 1994, four Canadian Astronauts were sealed off in a hyperbaric chamber at the Canadian Government's Defense and Civil Institute for Environmental Medicine in Toronto, Canada. This space lab training mission lasted seven days and was the first to be conducted with astronauts outside of Russia. The objective of this mission was to give Canadian astronauts, space scientists and the staff of the Canadian Space Agency (CSA), the opportunity to gain first hand experience on preparational and operational aspects of a typical space mission. Twenty-one scientific experiments involving six countries from several disciplines were involved in this mission. This paper describes the goals and preliminary results of a psychological experiment/training program that used the CAPSULS mission as a test bed for its application in the manned space flight environment. The objective of this project was to enhance the understanding of small group behaviour with a view to maximizing team effectiveness and task accomplishment in teams living and working in isolation under difficult and confined conditions. The application of this model in the light of future missions is a key thesis in this paper.

Psychological considerations of man in space: problems & solutions.

With concrete plans for long duration flight taking form a new impetus is lent to preparing man for this hostile and unnatural environment. Cramped conditions, isolation from family and loved ones, work stress, fear, and incompatibility with fellow crew, are but a few of the problems suffered by astronauts and cosmonauts during their long missions in orbit about the earth. Although criteria for selection of crew is one aspect of attacking the problem, it has not solved it. Notwithstanding good selection, team combination, and counselling before flight, problems have still occurred with unwanted consequences. Incompatibility of team members, far from being the exception, has been frequent. This has been detrimental both physiologically and psychologically for the individual as well as for the operational success and safety of the missions. Because problems will inevitably occur in future long duration missions, especially when they are of international and multi-cultural nature, the importance of dealing with them is underlined. This paper takes a different approach towards ameliorating these problems, namely that of psychological group training before a mission.

Regulatory regions 3' of the immunoglobulin heavy chain intronic enhancer differentially affect expression of a heavy chain transgene in resting and activated B cells.

We have compared the expression patterns of three Ig heavy chain transgenes. The three constructs differ only by deletion of J-C intron sequences located downstream of the Emu enhancer region. When stably transfected into a myeloma cell line, all three constructs are expressed at comparable levels. However, transgenic mice carrying each construct show dramatic differences in transgene expression. Our results indicate that, in addition to the Emu enhancer, at least two regions, RegA and RegS, within the J-C intron influence transgene expression. RegA, located directly downstream of the core Emu enhancer, is involved in up-regulation of transgene expression after LPS activation of splenocytes. RegS, located within or downstream of the Smu switch region, is important for normal levels of transgene expression in splenocytes of heavy chain transgenic mice.