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Biomedical subjects

J Kass

Publications and source records attributed to J Kass.

17 recordsLinked to original sources
PubMed2005

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.

Computer Security↗
PubMed2001

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.

Animals↗
PubMed2001

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.

Animals↗
PubMed1999

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.

Amino Acid Sequence↗
PubMed1999

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.

Aerospace Medicine↗
PubMed1995

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.

Animals↗
PubMed1994

Coverage of genetic technologies under national health reform.

This article examines the extent to which the technologies expected to emerge from genetic research are likely to be covered under Government-mandated health insurance programs such as those being proposed by advocates of national health reform. Genetic technologies are divided into three broad categories; genetic information services, including screening, testing, and counseling; experimental technologies; and gene therapy. This article concludes that coverage of these technologies under national health reform is uncertain. The basic benefits packages provided for in the major health reform plans are likely to provide partial coverage of experimental technologies; relatively broad coverage of information services; and varying coverage of gene therapies, on the basis of an evaluation of their costs, benefits, and the degree to which they raise objections on political and religious grounds. Genetic services that are not included in the basic benefits package will be available only to those who can purchase supplemental insurance or to those who can purchase the services with personal funds. The resulting multitiered system of access to genetic services raises serious questions of fairness.

Federal Government↗
PubMed1991

Subjective luminous line perception under changing g-load and body-positions in parabolic flight.

Five healthy subjects were subjected to parabolic flight with laterally tilted head, trunk, or body position. A vertical luminous line was viewed by the subjects in a head-fixed goggle device. During normal, hyper- and hypogravity phases subjective luminous line orientation was measured. The data imply that stimulation of the neck position receptors markedly influences the perception of the subjective vertical as well as mechanisms of convergence of otolithic signals and visual information within the brain.

Adult↗
PubMed1990

Effect of inhaled triamcinolone on bronchial hyperreactivity and airways obstruction in asthma.

We measured changes in methacholine bronchial hyperreactivity and airways obstruction in 37 asthmatics treated with inhaled triamcinolone for 6 weeks. All received regular bronchodilator therapy but not steroids or cromolyn. Initial studies included spirometry and the provocative concentration of methacholine required to decrease the FEV1 by 20% (PC20). Patients were randomized into two groups: those given inhaled triamcinolone, 200 micrograms four times daily (T) by metered dose inhaler, and those given a placebo inhaler (P). Daily AM and PM peak flow measurements were recorded, while PC20 and pulmonary function tests were obtained at 3 and 6 weeks. Change in canister weight was used to determine treatment compliance. The PC20 of T increased from a baseline 1.00 mg/mL to 2.90 mg/mL at 6 weeks, whereas in P it decreased from 1.15 mg/mL to 1.05 mg/mL. Percent change in PC20 (delta PC20) for each patient was defined as: [(PC20(week 6)--PC20(baseline]/PC20 (baseline)] X 100. At 6 weeks, this was 290% in T versus 65% in P (P less than .05). Likewise, at 6 weeks T was significantly greater than P with respect to: delta FEV1 (4.1% versus -3.8%, P less than .05) and delta FEF25-75% (20.3% versus -5.6%, P less than .01). Patients were further separated into higher and lower complier subgroups. In T, higher compliers showed more improvement at 6 weeks than lower compliers in: delta PC20 (533.3 versus 67.8%, P less than .05), delta FEV1 (8.7 versus -1.7%, P less than .01), and delta FEF25-75% (31.9 versus 1.1%, P less than .01). These data suggest that triamcinolone improves bronchial hyperreactivity as well as airways obstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Inhalation↗
PubMed1989

Influence of proprioceptive information on space orientation on the ground and in orbital weightlessness.

Conscious space orientation depends on afferent information from different sense organs including the labyrinth, the eyes, tactile cues from the skin, joint receptors, muscle spindles, tendon organs and possibly viscera. An important role is played by impulses from the cervical position receptors in interaction with concomitant information from the otolith system. In order to isolate the effect of cervical position receptors from that of the otolith system, space experiments in orbital weightlessness and in parabolic aircraft flight were performed. It was found that stimulation of the neck receptors in weightlessness markedly influences the perception of the subjective vertical and horizontal and in addition has a weak effect on ocular torsion.

Adaptation, Physiological↗
PubMed1984

Effects of rectilinear acceleration and optokinetic and caloric stimulations in space.

During the flight of Spacelab 1 the crew performed a number of experiments to explore changes in vestibular function and visual-vestibular interactions on exposure to microgravity. Measurements were made on the threshold for detection of linear oscillation, vestibulo-ocular reflexes elicited by angular and linear movements, oculomotor and posture responses to optokinetic stimulations, and responses to caloric stimulation. Tests were also conducted on the ground, during the 4 months before and on days 1 to 6 after flight. The most significant result was that caloric mystagmus of the same direction as on the earth could also be evoked in the weightless environment.

Acceleration↗
PubMed1984

The European vestibular experiments in Spacelab-1.

A series of experiments were performed in the Spacelab-1 mission on November/December, 1983, pre-, in-, and postflight. These experiments covered various aspects of the functions of the vestibular system, the inflight tests comprising threshold measurements for linear movements in three orthogonal axes, optokinetic stimulation, vestibulo-ocular reflexes under linear and angular accelerations, caloric stimulation with and without linear accelerations; pre- and postflight tests repeated the inflight protocol with the addition of subjective vertical and eye counter-rotation measurements using a tilt table. One of the most surprising and significant results was the caloric test: strong caloric nystagmus on the two subjects tested was recorded inflight; this was contrary to what was expected from Barany's convection hypothesis for caloric nystagmus.

Adaptation, Physiological↗
PubMed1978

Memory factors in vowel discrimination of normal and at-risk infants.

The role of memory factors in infant vowel discrimination was examined by studying the categorical versus continuous discrimination of very brief vowels and the effect on discrimination of the silent delay interval between the last familiar and the first novel stimulus. 8-week-old infants of normal and at-risk medical histories were presented in a nonnutritive sucking paradigm with either a between-category or a within-category vowel shift. The results revealed reliable between-category but not within-category discrimination. In addition, the magnitude of the recovery in the between-category shift was related inversely to the duration of the shift delay interval. Finally, differences were observed between normal and at-risk infants in their initial attention to, discrimination of, and memory for short vowels. These findings were discussed in terms of the relative contributions of auditory and phonetic short-term memory in infant and adult vowel perception.

Attention↗
PubMedDate not supplied

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.

Aerospace Medicine↗
PubMedDate not supplied

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.

Adaptation, Psychological↗