Biomedical subjects

Martin Hecht

Publications and source records attributed to Martin Hecht.

7 recordsLinked to original sources

PubMed2006

Shear viscosity of claylike colloids in computer simulations and experiments.

Dense suspensions of small strongly interacting particles are complex systems that are rarely understood on the microscopic level. We investigate properties of dense suspensions and sediments of small spherical Al2O3 particles in a shear cell by means of a combined molecular-dynamics and stochastic rotation dynamics simulation. We study structuring effects and the dependence of the suspension's viscosity on the shear rate and shear thinning for systems of varying salt concentration and pH value. To show the agreement of our results with experimental data, the relation between the bulk pH value and surface charge of spherical colloidal particles is modeled by Debye-Hückel theory in conjunction with a 2 pK charge regulation model.

Journal Article↗

PubMed2006

Botulinum toxin in patients with multiple sclerosis.

Nearly all patients with multiple sclerosis (MS) will develop spasticity in the course of their disease. This symptom accounts for most of the handicap and impairment in the quality of life. Treatment with botulinum toxin will enable an efficient and safe alleviation of spasticity and the problems involved, given a realistic definition of the therapeutic target and a graded multimodal approach. Treatment may fail for a great number of reasons that require diligent analysis. Compared with other disorders resulting in spasticity as well, MS does not constitute a monophasic disorder but is influenced by many factors. Treatment of spasticity in MS must therefore be guided by its particular aspects.

Botulinum Toxins, Type A↗

PubMed2005

Discussing living wills. A qualitative study of a German sample of neurologists and ALS patients.

Patients suffering from amyotrophic lateral sclerosis (ALS) eventually lose their ability to communicate their treatment preferences in later stages of the disease. A living will enables ALS patients to specify their choices concerning life-sustaining treatment in advance. Our premise was that completion of a living will should be preceded by a discussion between patient and physician. We conducted a qualitative study of a sample of 15 neurologists and 15 ALS patients from two neurology centers in Germany. Our aim was to explore how discussions about living wills are undertaken. Data analysis followed grounded theory techniques. Our findings showed that both the patients and the physicians considered living wills to be closely connected to forthcoming death. Physicians waited for respiratory failure to occur before they informed ALS patients about living wills, an information strategy that we called the "wait-and-see-policy". The patients completed their living will when they had accepted the hopelessness of their disease. They mostly used living will forms and did not see the necessity to set down disease-specific preferences. They intended to wait for symptoms to emerge before they made the decision about whether or not to accept life-sustaining treatment. The patients as well as the physicians pursued a wait-and-see policy towards end-of-life care, thus weakening the purpose of living wills. Our results point to the necessity and importance of an open and honest patient-physician communication which is a prerequisite for the discussion of living wills.

Adolescent↗

PubMed2005

Simulation of claylike colloids.

We investigate the properties of dense suspensions and sediments of small spherical silt particles by means of a combined molecular dynamics and stochastic rotation dynamics (SRD) simulation. We include van der Waals and effective electrostatic interactions between the colloidal particles, as well as Brownian motion and hydrodynamic interactions which are calculated in the SRD part. We present the simulation technique and first results. We have measured velocity distributions, diffusion coefficients, sedimentation velocity, spatial correlation functions, and we have explored the phase diagram depending on the parameters of the potentials and on the volume fraction.

Journal Article↗

PubMed2005

Neurophysiological measures in amyotrophic lateral sclerosis: markers of progression in clinical trials.

In this review we evaluate clinical neurophysiological methods, originally described for use in diagnosis that can be applied to measurement of change during the progress of amyotrophic lateral sclerosis (ALS). Such measurements are potentially important in clinical trials, and also in clinical practice. We have assessed methods for lower and upper motor neuron function, including conventional EMG, nerve conduction and F-wave studies, the derived Neurophysiological Index, motor unit counting methods (MUNE), and transcranial magnetic motor cortex stimulation. We have also addressed the validity of measurements of electromechanical coupling. Methods for measuring muscle strength are beyond the scope of this review. We conclude that MUNE, M-wave amplitude and the Neurophysiological Index are sufficiently reliable, sensitive, and relevant to the clinical problem of ALS, to be used in clinical trials in the disease. Transcranial magnetic stimulation is of limited value, but a combination of the measurements made as part of this technique may also be useful. We conclude that clinical neurophysiological techniques should now be used in measuring change in clinical trials in ALS.

Amyotrophic Lateral Sclerosis↗

PubMed2004

Antrochoanal polyp and obstructive sleep apnoea in children.

Antrochoanal polyps were first documented in the 18th century. They represent one of the most common types of nasal polyps in children without cystic fibrosis. Only a few reports on children who had a history of snoring due to an antrochoanal polyp and only two cases where the antrochoanal polyp caused documented obstructive sleep apnoea (OSA) have been published so far. This report adds a third case of paediatric OSA induced by an antrochoanal polyp in a 12-year-old boy. After endonasal endoscopically-controlled polypectomy and a recurrence, transoral osteoplastic antrotomy in combination with endoscopic endonasal polypectomy eliminated the antrochoanal polyp and OSA was resolved. The authors have reviewed essential historical aspects about children suffering from snoring and/or OSA caused by an antrochoanal polyp.

Child↗

PubMed2002

Subjective experience and coping in ALS.

OBJECTIVE: Amyotrophic lateral sclerosis is a rapidly progressive and fatal disease which has no known cure and limited symptomatic treatment. While coping strategies in more common diseases are widely assessed, coping is poorly understood in ALS. METHODS: We examined 41 ALS patients using a standardised interview, a validated coping self-rating questionnaire and a self-rating depression scale. The evaluation was repeated after six months. RESULTS: "Loss of speech", "loss of mobility" and "the poor prognosis" were the most frequent answers in the standardised interview to questions regarding the worst aspect of the disease. Pain was seldom mentioned. "Family members" were most helpful in coping with the disease, followed by "unspecific mechanisms" and "technical aids". None of our patients expressed a wish for assisted suicide. In comparison with other fatal diseases, patients with ALS had similar rankings in the coping mechanism of "rumination", but lower rankings in "search for social integration", "defence of fear", "search for information and communication". In contrast,* "search for hold in the religion" was of high importance for our ALS patients. In the follow-up examination the importance of "search for information and communication" increased. CONCLUSION: The results emphasise the importance of "loss of speech" and the importance of the caring family as well as the availability of technical aids in ALS. Coping in ALS seems to be based mainly on "rumination" and *"hold in the religion", but the increasing importance of "search for information" indicates that the sustained offer of information is essential.

Adaptation, Psychological↗