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Biomedical subjects

J Stelling

Publications and source records attributed to J Stelling.

16 recordsLinked to original sources
PubMed2003

The systems biology markup language (SBML): a medium for representation and exchange of biochemical network models.

MOTIVATION: Molecular biotechnology now makes it possible to build elaborate systems models, but the systems biology community needs information standards if models are to be shared, evaluated and developed cooperatively. RESULTS: We summarize the Systems Biology Markup Language (SBML) Level 1, a free, open, XML-based format for representing biochemical reaction networks. SBML is a software-independent language for describing models common to research in many areas of computational biology, including cell signaling pathways, metabolic pathways, gene regulation, and others. AVAILABILITY: The specification of SBML Level 1 is freely available from http://www.sbml.org/

Database Management Systems↗
PubMed2001

Ability of laboratories to detect emerging antimicrobial resistance: proficiency testing and quality control results from the World Health Organization's external quality assurance system for antimicrobial susceptibility testing.

The accuracy of antimicrobial susceptibility data submitted by microbiology laboratories to national and international surveillance systems has been debated for a number of years. To assess the accuracy of data submitted to the World Health Organization by users of the WHONET software, the Centers for Disease Control and Prevention distributed six bacterial isolates representing key antimicrobial-resistance phenotypes to approximately 130 laboratories, all but one of which were outside of the United States, for antimicrobial susceptibility testing as part of the World Health Organization's External Quality Assurance System for Antimicrobial Susceptibility Testing. Each laboratory also was asked to submit 10 consecutive quality control values for several key organism-drug combinations. Most laboratories were able to detect methicillin (oxacillin) resistance in Staphylococcus aureus, high-level vancomycin resistance in Enterococcus faecium, and resistance to extended-spectrum cephalosporins in Klebsiella pneumoniae. Many laboratories, particularly those using disk diffusion tests, had difficulty in recognizing reduced susceptibility to penicillin in an isolate of Streptococcus pneumoniae. The most difficult phenotype for laboratories to detect was reduced susceptibility to vancomycin in an isolate of Staphylococcus epidermidis. The proficiency testing challenge also included a request for biochemical identification of a gram-negative bacillus, which most laboratories recognized as Enterobacter cloacae. Although only a small subset of laboratories have submitted their quality control data, it is clear that many of these laboratories generate disk diffusion results for oxacillin when testing S. aureus ATCC 25923 and S. pneumoniae ATCC 49619 that are outside of the acceptable quality control range. The narrow quality control range for vancomycin also proved to be a challenge for many of the laboratories submitting data; approximately 27% of results were out of range. Thus, it is important to establish the proficiency of laboratories submitting data to surveillance systems in which the organisms are tested locally, particularly for penicillin resistance in pneumococci and glycopeptide resistance in staphylococci.

Anti-Bacterial Agents↗
PubMed1999

Learning to listen: serendipitous outcomes of a research training experience.

Experience gained in a qualitative research-training project led a group of clinical nurse specialists to discover the value of using research interview strategies in their clinical work. Clinical interviews, designed to garner data sufficient to decide on interventions, narrow the focus of the interviewer to information deemed relevant to that end. Research interview strategies involve a temporary suspension of the search for intervention, encourage a full description of the respondent's story and experience, and emphasise really listening to that story. In this case it is the respondent who decides what the story is and what information is relevant. This leads the interviewer to a fuller understanding of the context and perceptions of the respondent. The understanding and knowledge thus obtained comprise a better foundation for devising interventions which are individualised and specific to the individual and family.

Communication↗
PubMed1998

Dephosphorylation activates the purified plant plasma membrane H+-ATPase--possible function of phosphothreonine residues in a mechanism not involving the regulatory C-terminal domain of the enzyme.

The plasma membrane H+-ATPase was purified from tobacco cells (line BY-2). After solubilization by lysophosphatidylcholine followed by separation on a glycerol gradient, a fraction with a high specific activity of 9 micromol ATP x min(-1) x mg protein(-1) was obtained, in which the H+-ATPase polypeptide represented at least 80% of the protein. The incubation of this fraction in the presence of alkaline phosphatase increased H+-ATPase activity by 40%, in a manner consistent with dephosphorylation of the enzyme itself. The hydrolytic activity of the solubilized enzyme and its proton translocating activity, after reconstitution into proteoliposomes, were stimulated to the same extent. Alkaline phosphatase treatment was also accompanied by a 92% decrease in the H+-ATPase phosphothreonine content, whereas the phosphoserine residues were almost unaffected. The dephosphorylation induced a slight decrease of the affinity of the enzyme towards ATP. The purified enzyme was not activated by lysophosphatidylcholine addition nor by trypsin-mediated proteolysis, two treatments reported to release the inhibitory control by the C-terminal domain of the H+-ATPase and to increase the affinity of the enzyme towards ATP. Based on these results, the regulatory phosphorylation evoked by alkaline phosphatase most likely differs from the autoinhibitory control of the H+-ATPase by its C-terminal domain.

Alkaline Phosphatase↗
PubMed1996

Different acute effects of single-axis and multi-axis hand-arm vibration.

Under laboratory conditions the effects of single-axis and multi-axis hand-arm vibration exposure on several strain parameters were tested in up to 20 male subjects. As parameters of these acute effects, the biodynamic vibration behavior of the hand-arm system, the electrical activity of the most affected muscle groups, the skin temperature, the vibration sensitivity of the fingertips, and the subjective vibration sensation were measured. When comparing simulated three-axis vibration exposure with single-axis vibration exposure, synergistic effects in the form of an increasing reaction could be found. It could be proven that the vector sum of the frequency-weighted acceleration in the three axes represents the acute effects better than does the weighted acceleration in the main axis alone. This summation has to take into account the relatively lower effects of vibration in the x- or y-direction compared with the z-direction. On the basis of the experimental results a new proposal for frequency weighting of the three different axes and an energetic summation procedure are derived. Application of this knowledge in the International Standard ISO 5349 is proposed.

Adolescent↗
PubMed1994

Breakpoints and continuities: a case study of reactive change.

In 1987, nursing administrators effected radical changes on a pediatric psychiatry ward: A bachelor's degree in nursing science became mandatory for nursing staff, family systems nursing was introduced, and postdischarge nursing follow-up was instituted. To convey how they accomplished the changes, a case history of change on the ward is presented. It suggests that there were many driving forces. Factors most important to nursing's success included a strong vision of nursing, sufficient pain or discomfort to motivate change, the ability to recognize and seize opportunities, and the linking of change to existing institutional practices, policies, and values.

Child↗
PubMed1988

The contractile properties and movement dynamics of pigeon eye muscle.

The lateral rectus (LR) muscle of the pigeon was directly stimulated in situ at 41 degrees C. The length tension relationships for active and passive tension were investigated to determine the optimum muscle length (Lo). Isometric responses to single and twin pulses, tetani and sinusoidal stimulation were measured. A linear relationship was found between length and active tension during stimulation. Increase in stimulation frequency produced a corresponding shift in tension with the slope of the curves remaining the same. At Lo (1.21 times resting length) the average contraction time of single twitches was 6.03 ms and the half-relaxation time was 7.77 ms. Stimulation frequencies of 200 Hz and over gave rise to a fused tetanus. Tension increased to a maximum at 200 Hz and rate of tension rise saturated at 600 Hz. The tension response to tetanic stimulation was linear over the range 70-180 Hz. Maximum tetanic tension was around 3.48 N/cm2 and the twitch:tetanus ratio was 0.164. Prolonged activation at fusion frequency showed a high fatigue resistance. Sinusoidal stimulation with pulse trains of 100-180 Hz produced a sinusoidal response over the frequency range 0.6-40 Hz, from which the gain and phase relationships were determined. The muscle response approximates a first order low pass filter, with a characteristic frequency of 11.2 Hz. There is an additional phase lag, equivalent to the response latency, of 2.89 ms. The results are compared to the contractile properties of mammalian eye and avian skeletal muscle. The frequency response of the LR is compared to that of cat soleus and gastrocnemius and to pigeon eye movement dynamics.

Animals↗
PubMed1987

Muscle fibre types in the external eye muscles of the pigeon, Columba livia.

Fibre typing with antisera raised against specific myosin types from muscles of known physiological properties were used to characterise the fibre types within the oculorotatory muscles of pigeons. Fibres reacting strongly to antiserum anti-ALD (specific for tonic fibre myosin) were found lying along the global margin of the muscle and also in a layer lying immediately beneath a discrete band of fibres running along the orbital margin. These fibres resembled those of the skeletal muscle ALD in their type properties. Using another antiserum, anti-I, specific for slow twitch and to a lesser extent, slow tonic myosins, it was possible to identify another slow fibre type which formed the orbital layer and also lay scattered randomly through the body of the muscle. No equivalent to this type was found in the skeletal muscles ALD or iliofibularis. The remaining fibres which did not react with either anti-ALD or anti-I formed 58% of the fibre population and reacted with an antiserum specific for fast myosin. However, their response to alkali preincubation suggests that the fast fibres of eye muscles also contain a myosin which is different from those in skeletal muscle.

Adenosine Triphosphatases↗
PubMed1986

The mechanics of pigeon eye movements--are they like other vertebrates?

The lateral rectus muscle of the pigeon eye was driven by stimulation of the abducens nucleus. Eye rotation was measured with an opto-electronic movement detector. Eye position was linearly related to stimulation frequency in the range 40-110 Hz and saturated at frequencies above 250 Hz. Maximum eye velocity of 240 degrees/s was obtained with a stimulation frequency of 360 Hz. Stimulation with sinusoidally modulated pulse frequencies (40-110 Hz) over the modulation frequency range 0.01-6.0 Hz were used to determine the gain and phase relationships of the oculomotor system. The response approximates a first order low pass frequency model with a characteristic frequency of 0.45 Hz at high frequencies. There is an additional phase lag equivalent to a time delay of 9.8 ms. The results are compared with similar experiments performed on the dogfish and cat oculomotor systems.

Abducens Nerve↗
PubMedDate not supplied

But is it nursing?

Should hospitals adopt a standardized workload measurement instrument? Would it lead to better and/or more objective staffing decisions? How would it affect nursing work and staff nurses? The author uses sociological research to address these and other questions about the implications of adopting a workload measurement instrument.

Humans↗