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Biomedical subjects

Fischer

Publications and source records attributed to Fischer.

9 recordsLinked to original sources
PubMed2004

Applications of shape memory alloys in medical instruments.

Endosmart GmbH was founded in January 2002 and is a spin-off from the Forschungszentrum Karlsruhe. Endosmart focuses on the use of NiTi mostly outside the implant market. Therefore a lot of tools especially for instruments for minimally invasive surgery are being developed. Innovative hingeless graspers, baskets, flexible instruments and also parts of instruments, just to name a few of them. A new focus of our work is the excellent compatibility to magnetic resonance imaging (MRI) systems, and this has led to the development of the first MRI compatible needles for use in a surgical robot. New in the field of NiTi is the porous foam and its compatibility to human cells and first results show new possibilities in growing artificial cells. In combination with the elasticity of the foam a new generation of e.g. medical bone implants could be possible. This paper describes several developments in the field of instruments of shape memory alloys (SMAs) made also at Endosmart.

Journal Article↗
PubMed2001

Transplantation of genetically modified fibroblasts expressing BDNF in adult rats with a subtotal hemisection improves specific motor and sensory functions.

OBJECTIVE: We have previously reported that grafting fibroblasts genetically modified to express brain-derived neurotrophic factor (BDNF) into a subtotal cervical hemisection site that destroys the entire lateral funiculus will promote regeneration of rubrospinal axons and growth of other axons, prevent atrophy and death of axotomized red nucleus neurons, and improve forelimb use during spontaneous vertical exploration. We have now extended these studies by using additional sensorimotor tests to examine recovery. METHODS: The range of tests used included those in which the intervention did not improve recovery, those in which the intervention was associated with recovery, and those that showed little deficit. The selected tasks tested both sensory and motor functions and both forelimb and forelimb function. We used the open-field locomotor rating scale (BBB), locomotion on a narrow beam, forelimb use during swimming, horizontal rope walking, and a somatosensory asymmetry (patch-removal) test. After testing during an 8-week recovery period, a second lesion was made just rostral to the initial lesion/transplant site to test the role of the transplant in recovery. The rats were then retested for a further 5 weeks after the repeated lesion. RESULTS: The horizontal rope, swim, and patch-removal tests were reliably sensitive to the subtotal hemisection injury. Fb/BDNF-transplanted animals recovered motor functions on the horizontal rope-crossing test, and this recovery was abolished by a second lesion just rostral to the first lesion/transplant. In the patch-removal test, the latency to contact the affected limb was shorter in Fb/BDNF-treated rats than in the control group, and this effect was completely abolished by a second lesion. CONCLUSIONS: The rope-crossing and patch-removal tests are particularly useful tasks for assessing the beneficial effects of BDNF-expressing grafts in this injury model.

Animals↗
PubMed1977

[Acute liver damage due to thioacetamide. Morphology, biochemistry and neurophysiologic comparison with cerebrotoxic substances].

Morphology, biochemistry and neurophysiological comparisons with effects of brain-toxic substances. The acute damage of the liver by thioacetamide is characterized neurophysiologically by a far--reached synchronous beginning of cortical and subcortical alteration of activity, a retardation of cortical and subcortical EEG, threshold increase of the EEG--arousal reaction, reductions in amplitude of centrally evoked potentials and increase of acoustically evoked potentials. We impute that according to an acute "toxic" damage of the liver a "membrane hyperpolarisation" results in all or nearly all areas of the brain. A general decrease of excitability of the brain seems consequently plausible. In opposition to this results only activities of the cortex or structures nearby the cortex (areas above the midbrain reticular formation) will be affected by exogenous arterial hyperammoniemia up to 1700 mug/100 ml.

Acetamides↗