Biomedical subjects
M Turnheim
Publications and source records attributed to M Turnheim.
[Electrophysiological studies in vincristin-polyneuropathy (author's transl)].
21 Patients with malignant brain tumors were treated with vincristine (1,4 mg/m2) in the course of combination chemotherapie, given in 14 days series over 3 months up to 26 month. 18 patients developed clinical signs of a sensory and 4 patients of a sensomotoric polyneuropathy. Changes in nerve conduction velocity of the N. peronaeus and N. suralis and amplitude of the evoked muscle response (M. extensor digitorum brevis) and nerve action potential were studied in dependency of the total vincristine dosage. The following conclusions were drawn. 1. Clinical occurrence of vincristine polyneuropathy and decrease of nerve conduction velocity of peroneal and sural nerve and the amplitude of the muscle response and nerve action potential are dosage dependent. 2. Sensory fibres appear to be damaged earlier and more severe than motor fibers, but this difference was statistically not significant. 3. Nerve conduction velocity of peroneal and sural nerve is normal or slightly decreased in vincristine polyneuropathy, but the amplitude of the evoked response in extensor digitorum brevis muscle and of the nerve action potential of the suralis nerve are markedly diminished. This result indicates that vincristine polyneuropathy is of primary axonal orgin. 4. If vincristine dosage is reduced to half or vincristine is discontinued after a reduction of the potential amplitude in the extensor digitorum brevis muscle below 1 mV, severe, not reversible polyneuropathies may be avoided.
Coupling between neuronal activity and focal blood flow in experimental seizures.
Local blood flow, ECoG and single cortical neurone activity were recorded simultaneously from single microelectrodes in 17 cats. Seizures were induced by repeated intravenous injections of pentylenetetrazol (PTZ, 10-20 mg/kg) or by local application of 1 M Na-penicillin. Seven to 20 sec after appearance of burst activity in cortical neurones and ECoG, focal flow increased up to 300% of control. The extent of this flow increase was significantly correlated with the change in firing rate of the neurones. With cessation of seizure activity the flow returned to or below control values. Forty to 70 mg/kg PTZ caused status epilepticus with high voltage rhythmic discharges lasting 30 min-2 h. In 3 cats with status, the flow decreased below control despite persisting seizures, indicative of uncoupling between activity and flow. The delayed coupling between activity and flow during drug-induced seizures indicates a metabolic mediator. Uncoupling observed in cases with long lasting seizures may be due to brain oedema following increased permeability of the blood-brain barrier.
Combination chemotherapy of malignant glioma. Effect of postoperative treatment with CCNU, vincristine, amethopterine and procarbazine.
Explore the source record for details and available documents.
A technique for recording local blood flow and neuronal activity with a single microelectrode.
A technique is presented for recording both local blood flow, by means of hydrogen clearance method, and neuronal activity of the cat's cortex using a single microelectrode. The requirements of electrodes for recording cerebral blood flow are different from those for recording extracellular spikes. Only electrodes within a small range of impedance (measured at 10 Hz) are suitable to record both. A bridge method is used for the recordings. The bridge signal is split in order to amplify cell activities and H2 responses separately. Three examples demonstrate the method and the importance of appropriately selected electrodes.
[Characteristic features of ischaemic strokes in young adults (author's transl)].
Clinical symptoms, angiographic findings and risk factors were recorded according to a classification system in 28 women and 39 men who suffered an ischaemic cerebral stroke before the age of 40. This enabled correlations to be made within the group of young patients and the discovery--by comparison with a corresponding group of patients over 40--of statistically significant age-specific features of cerebro-vascular disease. Vascular lesions in young patients show a sex-specific distribution and a characteristic relationship to clinical symptoms. The prognosis is more favorable in young patients; risk factors which predispose to stroke and influence its further development are less frequent. It is, therefore, suggested that characteristic features of strokes in young adults can be partially explained by the fact that they are usually caused by single pathological alterations in otherwise healthy persons.
Brain perfusion and neuropsychological test scores: a correlation study in aphasics.
Explore the source record for details and available documents.
Neuronal activity and focal flow in experimental seizures.
Explore the source record for details and available documents.
[Clinical picture, cerebrospinal fluid findings, and pathological anatomy of subacute demyelinating encephalitis ("mixed form" of multiple, diffuse and concentric sclerosis)].
Explore the source record for details and available documents.
Flow and compartmental weight in relation to the cours of stroke.
Using a scintillation camera system, hemispheric and regional cerebral blood flow was measured repeatedly during the course after a stroke. In 20 patients who improved clinically mean hemispheric and regional flow and relative weight of rapidly perfused compartment increased, while these values decreased in 15 patients, on an average, whose clinical condition deteriorated or did not change. The changes of flow and relative weight were significantly different between the two groups. Futhermore, the relationship between changes in clinical condition, scored according to a rating scale, and changes in flow and compartmental weight was proved by significant Spearman rank correlation coefficients. In six cases hyperperfused areas in locations of disturbed neurological function were observed; these areas were found to be ischemic at measurements done early and late in the cours after the stroke. This type of hyperperfusion was related to beneficial prognosis. The results indicate a shift of tissue form fast to slowly cleared compartment after a cerebrovascular attack. If tissue morphology is not entirely destroyed, recovery might occur; this results in an increase of recorded weight of rapidly clearing compartments, which correlates to the clinical course.