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Biomedical subjects

M Halbach

Publications and source records attributed to M Halbach.

9 recordsLinked to original sources
PubMed1990

Nasopharyngeally and vertex recorded P300's in normal subjects.

The P300 waveform has been associated with cognitive activity during information processing, and the hippocampus has been discussed as a possible generator of this waveform. This being the case some would argue that it should be possible to record the P300 with a shorter latency and greater amplitude from an electrode placed as near the hippocampus as possible. Under local anaesthesia we inserted a specially constructed needle electrode through the left nostril in the recessus pharyngeus close to the hippocampus. The results did not support the hippocampal hypothesis. Nasopharyngeally recorded P300's were found to have significantly decreased amplitudes and extended latencies when compared to vertex recordings.

Adult↗
PubMed1989

Abnormal glucocorticoid dependent increase of spiperone binding sites on lymphocytes from schizophrenics in vitro.

The attempt was made to revise experimentally the concept of spiperone binding to human peripheral lymphocytes as a peripheral marker for schizophrenic disorder. Although it was not possible to detect differences in spiperone binding in freshly isolated lymphocytes from schizophrenics and controls, a significant increase in spiperone binding became apparent when the lymphocytes from patients were cultured in vitro in the presence of physiological concentrations of glucocorticoids. From our findings we have to assume that glucocorticoid-dependent regulation of the gene(s) containing the coding for spiperone binding sites could be functionally affected in distinct forms of schizophrenic psychosis. The glucocorticoid-induced increase of spiperone binding of human lymphocytes could represent a dynamic peripheral marker system. It further has to be investigated whether this concept of a regulatory dysfunction, as observed in lymphocytes from schizophrenic patients, can be applied to the CNS in general.

Adult↗
PubMed1987

Neuromuscular, autonomic and central cholinergic hyperactivity associated with thymoma and acetylcholine receptor-binding antibody.

Two cases of a neuromuscular hyperactivity syndrome associated with a proliferative thymoma and high serum titres of acetylcholine receptor (AChR) antibody with no signs of myasthenia are reported. The clinical and electrodiagnostic findings indicated generalized cholinergic hyperactivity at the neuromuscular junction and in the autonomic and central nervous system, resulting in generalized myokymia, excessive sweating and intermittent psychotic behaviour. The association with thymoma and raised AChR antibody suggests that this syndrome represents a unique type of autoimmune disease, in which antibodies against the AChR facilitate rather than inhibit cholinergic action. This conclusion is supported by the remission of symptoms after thymectomy and with immunosuppressive therapy in one case.

Adult↗
PubMed1979

Impairment of hormone dependent signal transfer by chronic SSPE virus infection.

In a CNS-derived cell line, the cellular response to hormonal stimulation, represented by the rise of intracellular cAMP levels, is impaired under the influence of a persisting neurotropic virus infection. This dysfunction is caused by the decrease in adenylate cyclase activity, most probably due to the virus-induced loss of active catalytic units.

Adenylyl Cyclases↗
PubMed1979

Rabies virus infection selectively impairs membrane receptor functions in neuronal model cells.

A persistent infection with rabies virus (HEP-Flury) was established in the CNS-derived hybrid cell line 108CC15 which possesses specific membrane receptors for prostaglandins, catecholamines and acetylcholine. We report a differential virus influence on the specific receptor response to PGE, isoproterenol and acetycholine as indicated by typical changes of the intracellular cyclic AMP levels. As the adenylate cyclase activity was unchanged in infected cells in vitro, a selective virus influence on specific receptors themselves or their coupling to the cAMP synthesizing system must be considered.

Animals↗
PubMed1978

Interferon enhances the fragility of lysosomes in L-929 mouse fibroblasts.

Infection of interferon-treated L-929 mouse fibroblasts with vaccinia WR virus is followed by severe cytolysis within 3 to 4 h. It is shown that this cytolysis cannot be caused by enzymes released from lysosomes into the cytosol. However, there is evidence that homologous interferon has a noxious effect on lysosomes. This phenomenon appears to be another aspect of the anticellular functions of interferon.

Animals↗
PubMed1975

First experiences with a documentation system via display terminals.

A documentation and monitoring system has been developed by members of the Department of Anesthesiology and the Department of Medical Data Processing of the Rheinisch-Westfälische Technische Hochschule Aachen. It is conceived in such a way that it should cover all the needs of the department, which is to say that every anesthesia done by a staff member should be documented, supervised and assisted by the computer service. The anesthesiological staff works only with 16 color visual display units, which are installed in the different operation theatres and in the intensive care unit of the department. These devices are used as an inquiry-response system for the dialogue between medical operator and computer. They display both alphanumerics and graphics in four different colors and modes. Information is entered in the system via so-called masks, which contain a larger section of information, and by on-line data recording.

Anesthesiology↗