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Biomedical subjects

P Schröter

Publications and source records attributed to P Schröter.

At least 19 recordsLinked to original sources
PubMed2003

Optical probing of a fractionally charged quasihole in an incompressible liquid.

In photoluminescence spectroscopy of a low-mobility two-dimensional electron gas subjected to a quantizing magnetic field, we observe an anomaly around nu=1 / 3 at a very low temperature (0.1 K) and an intermediate electron density (0.9 x 10(11) cm(-2)). The anomaly is explained as due to perturbation of the incompressible liquid at the Laughlin state due to close proximity of a localized charged exciton which creates a fractionally charged quasihole in the liquid. The anomaly of approximately 2 meV can be destroyed by applying a small thermal energy of approximately 0.2 meV that is enough to close the quasihole energy gap.

Journal Article↗
PubMed1994

Malignant gliomas--ploidy and DNA-content before and after therapy.

DNA ploidy and S-phase percentage from nine malignant gliomas (four glioblastomas, four anaplastic astrocytomas grade 3 and one anaplastic oligoastrocytoma grade 3) have been estimated by single cell cytophotometry on biopsy and necropsy specimens. All gliomas from biopsy material showed, with the exception of two diploid tumours, a polyploid-aneuploid DNA-pattern and stem-lines of different ploidy. The most frequent stem-lines were diploid and hyperdiploid. In necropsy material, following treatment i.e. operation and combined drug and radiation therapy, the heterogeneous nature of all malignant gliomas persisted. From seven aneuploid-polyploid gliomas four showed an elevation and three of them a decrease of DI values. Diploid tumors remained diploid. Because of marked heterogeneity of ploidy patterns and the small number of tumors investigated, ploidy changes could not be used for estimation of therapy efficacy and prognosis. Further studies will be necessary to answer this question.

Adult↗
PubMed1987

[Neuropathology of contralateral pain flexor reflexes].

Postmortem neuropathological and neuroanatomical--topographical examinations of brain section series of 10 patients with brain tumours of different histological type and localization with evidence of the Contralateral Pain Flexor Reflex (CPFR), described by Sayk (1982), were performed. In each case could be found an alteration or damage of functionally relevant structures of the ventrocaudal--lateral Thalamus, the intralaminar and intralaminar-reticular nuclei, of the Pulvinar thalami, the lemniscus medialis and the striopallidar nuclei formation by tumuorcellinfiltration and oedema. Possible ways of origin of the CPFR, pathophysiological possibilities and the prognostic relevance of this reflex are discussed.

Adult↗
PubMed1983

[Degree of malignancy in multiple sclerosis: clinicopathologic mortality study].

Basing on the neuropathologic findings (acute, subacute resp. chronic demyelination) in 58 cases with multiple sclerosis (MS) the determination of the degree of defect in relation to the duration of working capacity and disability has been carried out in comparison with an index made up for progression and malignancy of the disease. In the final phase of illness an acute exacerbation was noteworthy from the morphological point of view in 48.3% of the patients; in these cases was established a hightened index of malignancy. Differences of sex distribution a. o. pointed to a longer lasting defective (chronic) stage in women. The assessment of progression after a five-year period of examination by a limiting malignancy-index allows a probable prognosis to the chances and the risk of the developing process of disease and may be of importance for care.

Adult↗
PubMed1979

[Concentration of amino acids in synaptosomes of the rat brain in the preconvulsive phase of experimentally-induced seizures].

In the synaptic vesicae of rat brains the free amino acids were determined for control animals and experimental animals during the preconvulsive phase of induced cerebral spasms. Especially high concentrations were established for taurine, glutamic acid, asparaginic acid, gamma-aminobutyric acid and valine. Prior to a cerebral spasm the glutamic acid concentration is lowered in the synaptosomes.

Amino Acids↗
PubMed1977

[The problem of polyneuropathy in methaqualone medication].

Thirteen years after the introduction of methaqualone into therapy, investigators (namely, Finke, Spiegelberg, and Suchenwirth), by reference to individual cases, pointed out the possible development of polyneuropathies. This has not so far been confirmed despite worldwide use of the drug. Experiments on rats, which were conducted by the present authors, show a statistically significant decrease in maximum motor conduction speed, which is believed to be functional disorder. Clinical symptoms or nervous structural variations in the sense of polyneuropathy could not be observed.

Animals↗
PubMed1975

[Contribution to the subacute necrotic myelitis (Foix-Alajouanine) (author's transl)].

A case of a 54 years old man with an acute lumbalgia in result of heavy labour is described. With in 7 years he developed a progressive paralysis of the upper and lower motor neuron type and an insensibility of the inferior extremities. The protein content of the cerebrospinal fluid was increased. The cells were insignificantly increased in number. No tumour was detected. The man died at the age of 62 on intoxication by infected decubitus and focal pneumonia. Autopsy revealed subacute necrotic myelitis (Foix-Alajouanine) with enlarged, varicose, and thickened extramedullary veins of the sacral, lumbal, and lower thoracic spinal cord, which was soft and diminished in size. In the grey and white matter of the cord, there were found more numerous and more prominent vessels like an angioma capillare et venosum; complete and incomplete necrosis was observed, partially with plasmatic infiltration. Some nerve cells were still present. Nerve fibres without myelin mantle were found in the spinal cord as well as in the spinal roots. The authors support the suggestion that the subacute necrotic myelitis results from a dysgenesis of the spinal venous vessels.

Autopsy↗
PubMed1975

[Experimental allergic encephalomyelitis as a model for the study of therapeutic concepts for encephalomyelitis disseminata].

The induction of immunological tolerance with, and for, the caused organotypical antigen is a conception for a specific therapy for neuroimmunological diseases with at least a partial autoallergic pathogenesis. Appropriate to a set step-by-step programme for the development of antigen-specific therapy preventive tolerance experiments were carried out at the model of experimental allergic encephalomyelitis (EAEM) with allogenic myelin basic protein (BP) prepared from rabbits. The result is: 100 ug BP given intravenously simultaneously with 100 ug BP in incomplete Freud's adjuvant given intracutanously twice a week and 40 mg Cyclophosphamid given daily during the minor clinical incidence rate and no signs of EAEM pathomorphologically. A longlasting tolerance for the BP could be obtained as a test proved after 100 days. Hints are given for further potential therapeutic treatments, such as the use of antigen bound chemically to the immunosuppressive drug or the use of chemically modified BP for the induction of a specific tolerance.

Animals↗