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Biomedical subjects

M Stöhr

Publications and source records attributed to M Stöhr.

At least 109 records · Page 6Linked to original sources
PubMed1977

[Contribution to facial spasm (author's transl)].

Clinical, electromyographic, neurographic, and nystagmographic results of 20 cases of facial spasm are reported. The syndrome is discussed with reference to parabiosis of the facial nerve and the "ephapse" theory, the localization of facial nerve lesions, and possible etiologic factors of parabiotic changes. For the pathogenesis chronic and subclinical preimpairments of facial nerve axons are postulated as causing, after subsequent additional affections, an "ephaptic" transfer to neighboring fibers. Therapeutic possibilities are discussed.

Adult↗
PubMed1977

Flow microfluorometric monitoring of the interaction of lipid vesicles with cells.

Flow microfluorometric techniques have been applied to experiments concerned with the penetration of cells by lipid vesicles. The high sensitivity of laser flow systems enables to measure the weak fluorescence emitted by individiual liposomes tagged with perylene, inserted into their multilamellar layer. The total fluorescence of cells which habe incorporated such perylene-loaded liposomes could be measured and well separated from that unbound liposomes. Significant differences in the incorporation rates of cationic and anionic liposomes were shown by means of time-course analyses of cellular fluorescence spectra. The advantages of the rapid data analysis by flow fluorescence techniques is discussed in comparison with conventional radio-isotopic methods.

Computers↗
PubMed1977

Extended application of flow microfluorometry by means of dual laser excitation.

A dual laser beam excitation device for flow analysis of biological particles has been developed. The aid of this arrangement is to increase the range of fluorescent agents employed so far in quantitative and qualitative cytochemistry. Combining an argon ion and a helium-cadmium laser two color fluorescence measurements were performed employing propidium iodide as a DNA stain and fluorescamine which stains total protein in fixed cells. Energy transfer processes between the antibiotic and DNA specific dye mithramycin and propidium iodide both being bound to nuclear chromatin were analyzed. Utilization of energy transfer processes is generally discussed as a mean to extract information about the structure and conformation of nuclear chromatin in situ. The application of a crypton ion laser with three lines near 400 nm and a single line at 350 nm having a light output in each range of nearly one Watt gives the opportunity of utilizing DNA fluorochromes which have an excitation maximum in the deep blue region, DNA spectra are shown employing mithramycin, the benzimidazol derivative 33258 (Hoechst) and the indol compound DAPI which has a high DNA specificity combined with a great stability under UV illumination. By separating two focussed laser beams at their intersecting points with the liquid sample stream the trajectory of each flowing cell crosses the beams sequentially, which causes a solitary dual excitation of each cell. The advantages of a solitary excitation device compared with a simultaneous one is discussed.

DNA↗
PubMed1977

Retrograde changes in motor and sensory conduction velocity after nerve injury.

Nerve section is followed by a reduction of motor and sensory conduction velocity in the proximal segment of the injured nerve. This reduction of velocity is associated with retrograde changes in fiber size. If reinnervation does not occur within the next 1 1/2--2 years, retrograde degeneration of nerve fibers results, and the amplitude of the evoked nerve potential in the proximal segment of the injured nerve decreases. This retrograde degeneration is probably significant in view of the poor results frequently obtained after nerve transplantation which is carried out too late.

Humans↗
PubMed1977

[Post-traumatic and post-operative paresis of the leg plexus (author's transl)].

Post-traumatic and post-operative leg-plexus paresis is often misdiagnosed as sciatic or femoral paresis and thus falsely thought to be rare. In 20 post-traumatic cases the cause was predominantly or exclusively due to sacral plexus damage, with paralysis of the muscles innervated by the sciatic nerve and of the gluteal muscles. The most frequent cause was severe pelvic trauma with ring fracture of the pelvis, separation of the symphysis and iliosacral gap or fracture of the hip joint. Postoperative leg-plexus paresis was noted in eight cases after total hip-joint replacement (predominantly damage to the lumbar plexus) and twice after operatively treated fracture of the acetabulum. Both pressure and tearing lesions can be the basic cause.

Adolescent↗
PubMed1977

[The stiff-man syndrome. A case report with regard to clinical, electromyographical and pharmacological signs (author's transl)].

Our electromyographical findings show no evidence for a spinal or neurogenic origin of muscle stiffness in stiff-man syndrome. It is assumed that the tonic muscle rigidity is induced by abnormal impulses from the brainstem. The measured latencies of electrically induced muscle spasm in the legs are in accordance with this hypothetic site of origin. Muscle stiffness and spasm are decreased by the GABA derivative Baclofen as well as by Clonacepam, which is preferable to Diazepam because of less intense sedation. Spasms are increased by Chlorimipramine which may by used as a provocative test in uncertain cases. These pharmacological influences suggest an imbalance between a gabaminergic inhibitory and a noradrenergic and/or serotoninergic excitatory neuronal system.

Aged↗
PubMed1977

Benign fibrillation potentials in normal muscle and their correlation with endplate and denervation potentials.

Fibrillation potentials in normal muscle are identical in origin with the 'spikes' in the endplate zone. The difference in shape is due to the site of the electrode. Both potential types are characterised by a high average maximal frequency and a very irregular discharge pattern. These properties distinguish them from the typical fibrillation potentials of the denervated muscle which show lower maximal discharge frequency, very small differences between consecutive time intervals, and slow up and down drifts in the discharge frequency. Less commonly, irregularly discharging fibrillation potentials are also observed in denervated muscle, which are exactly the same as those in the normal muscle, and which, therefore, may be assumed to have the same origin. It is only the rhythmically discharging fibrillation potentials which indicate a denervating process. The irregular fibrillation potentials, on the other hand, are of no pathological significance. The term benign fibrillation potentials is suggested for the latter.

Electrophysiology↗
PubMed1976

[Nerve-root damage from local injections (author's transl)].

Paravertebral injections of local anaesthetics (procaine hydrochloride, frequencly in combination with other substances) may damage cervical or lumbosacral nerve roots, depending on the site of injection. Five such iatrogenic lesions are described. Paravertebral injections of local anaesthetics also carry the risk of irreversible paraplegia and such treatment should therefore not be given in the cervical and lumbar segments.

Adult↗
PubMed1976

Lens culinaris lectin immobilized on sepharose: binding and sugar-specific release of intact tissue culture cells.

Lens culinaris lectin (LCL) covalently linked to 2B Sepharose binds tissue culture cells to the matrix. This is prevented by hapten sugars specific for LCL. Unlike other immobilized lectins, lens culinaris lectin allows the removal of bound cells from the matrix on addition of the specific sugars in a concentration-dependent manner. Binding and release occur under physiological conditions. Released cells continue to grow.

Cell Membrane↗
PubMed1976

[Orbicularis oculi reflex after facial paralysis: decreased amplitude of reflex response and spreading to all hemifacial muscles after reinnervation (author's transl)].

After the acute stage of peripheral facial paralysis with nerve degeneration we find some signs of paresis after reinnervation due to insufficient motor recovery and associated movements due to faulty reinnervation. Electromyographical investigation of the orbicularis oculi reflex can be used for the objective evaluation of these two phenomena. This shows the following typical signs: 1. The amplitudes of the early and late reflex response are decreased on the affected side proportionate to the degree of paresis. 2. The response occurs in all reinnervated hemifacial muscles as a result of misdirection of fibres which originally innervated the orbicularis oculi muscle.

Eyelids↗
PubMed1976

[Relapsing tetanus (author's transl)].

Tetanus relapses are caused by reactivated tetanus spores which have remained in the region of the wound, and made possible by unsatisfactory immunisation during a tetanus infection. From previously communicated individual case reports, the frequency of relapse, the length of the interval and the type of course are grouped together and compared with a case of our own. Electromyography plays a decisive role in the differential diagnosis of clinically similar syndromes and hysterical reactions. The characteristic electrophysiological findings are presented from the example of our own patient. Finally the therapeutic consequences are pointed out.

Adult↗
PubMed1976

[Post-anaesthetic palsies of brachial plexus (author's transl)].

Six cases of post-anaesthetic upper plexus palsy are described, in one case combined with an injury of the accessory nerve. These palsies are commonly due to stretching of the plexus when the arm is in an extreme position, especially when the neck is extended and flexed to the opposite side at the same time. Though mostly reversible, these lesions can incapacitate the patients for a long period and must be avoided. The methods of prevention are discussed in detail.

Adolescent↗
PubMed1976

[The ultimate electromyographic patterns in reinnervated muscle (author's transl)].

We investigated 59 patients in later stages after section and suture (n =23) or transplantation (n = 36) of the ulnar or median nerve. The most typical change in electromyographic pattern consists in a markedly increase of mean amplitude, due to an increased number and concentration of muslce fibers in the reconstituted motor-units. The mean duration and the incidence of polyphasic potentials are only slightly increased, indicating a nearly synchronous excitement of the different muscle fibers of the various motor-units. In no case there is a complete recovery; the mean amplitude of evoked potentials in reinnervated muscles varied from 32% in poor-, to 62% in satisfactory reinnervation, compared with the corresponding normal muscle in the opposite hand.

Electromyography↗
PubMed1975

[Periods of spontaneous discharges in paretic muscles. Low frequency rhythms of repetitive single, grouped and serial discharges (author's transl)].

Of 1800 patients examined electromyographically, 37 showed different forms of spontaneous low frequency periodical discharges in neuromuscular diseases. Besides the well-known high frequency bizarre discharges of 10-150 per sec in neuropathies and myopathies, low frequency periods of mostly polyphasic potentials are described as "low frequency bizarre discharge". Three types of these rhythms are distinguished: single, grouped, and serial discharges in various peripheral nerve and motor neuron and muscle diseases. The rate of the periods varied from 0.2 to 6 per sec, but was nearly constant in one and the same muscle. The discharge rate within the period may be higher, up to 150 per sec. The low frequency single discharges probably originate in the muscle fibers, the grouped and serial discharges possibly in the terminal branches of peripheral nerves. Rhythmical repetitive discharges may result from a reduction of stimulus threshold and accommodation of muscle- and nerve fibers respectively. Grouped and serial discharges may also be provoked by nerve stimulation or voluntary innervation.

Action Potentials↗
PubMed1975

The alkaline hydrolysis of nucleic acid for removal of RNA associated fluorescence in phenantridium related flow through cytofluorometry.

Flow through microfluorometry of phenantridium and fluoresceinisothiocyanate stained HeLa cells showed the absence of extranuclear RNA related fluorescence after prolonged hydrolysis of cells in ethanolic barium hydroxide. DNA distribution were as good as in RNAse treated samples. Distribution pattern of cellular protein/DNA ratios yielded greater resolution power than those after RNAse digestion. The cellular protein content has not been affected. The ethanolic hydrolysis has the advantage to be of less expense and to allow cell conservations for further measurements with other well preserving fixatives. Thus, application of glutaraldehyde has been proved to be valuable.

Barium↗