Search PubMed⌕ Search

Biomedical subjects

A Steck

Publications and source records attributed to A Steck.

47 records · Page 3Linked to original sources
PubMed1983

Glial proteins in canine distemper virus-induced demyelination. A sequential immunocytochemical study.

A temporal series of demyelinating lesions in experimental canine distemper virus (CDV) infection was examined with immunohistological techniques demonstrating myelin basic protein (MBP), myelin-associated glycoprotein (MAG), and glial fibrillary acidic protein (GFAP) on serial sections. The earliest lesions were characterized by decreased MBP and MAG and increased GFAP. During the further progression of the disease, MBP and MAG losses continued to match each other. There was no indication of MAG loss preceding the disappearance of MBP. In the more advanced lesions there was a marked decrease of GFAP positive cells. Since these findings differed considerably from similar immunohistochemical studies in progressive multifocal leukoencephalopathy (PML) where demyelination results from oligodendroglial infection, it was concluded that the oligodendroglial cell body is not the primary target of CDV. The marked astroglial changes were also considered to contribute to demyelination in CDV infection but the mechanism by which this happens remains unknown.

Animals↗
PubMed1983

Activated T lymphocytes in patients with multiple sclerosis.

We used four monoclonal antibodies designated MLR-1, -2, -3, and -4, specifically directed against determinants uniquely present on activated T lymphocytes to analyze peripheral blood lymphocytes (PBL) of patients with multiple sclerosis (MS). By indirect immunofluorescence techniques, we found that many PBL expressed one or more of these activation antigens. Thus, high percentages of MLR-2 positive cells were found in all 20 MS patients (66 +/- 12% in 13 patients with the remitting form and 57 +/- 14% in 7 patients with the progressive form). MLR-3 positive cells were found in three patients with the remitting form and five patients with progressive MS, MLR-4 in seven patients with remitting MS and in five with the progressive type. MLR-1 positive cells were prominent in only two cases (one remitting and one progressive). Discrepancies between expression of MLR antigens and molecules coded by the HLA-DR region (Ia antigens) were observed.

Adult↗
PubMed1983

[Isolation syndrome of the language area. Neuropsychologic and pathologic study].

A 60 year-old patient in whom spontaneous language was abolished still had a marked capacity for completing phrases and an irrepressible echolalia. From a formal point of view, linguistic ability remained at a high level. Auditory verbal comprehension was severely affected, but was not completely abolished. There was occipital blindness. Pathologic examination reveated extensive bilateral lesions in the regions supplied by the anterior and posterior cerebral arteries. Bilateral destruction of the supplementary motor areas was noted, but the perisylvian language areas were intact. These disorders constitute a syndrome of isolation of language areas which can be used to study anatomical correlations and particularly the role of the supplementary motor area in linguistic and paralinguistic processes.

Akinetic Mutism↗
PubMed1979

Distribution of tryptophan in erythrocytes, leukocytes and thrombocytes, and its binding to plasma albumin.

The extended theory about a dysfunction of the serotoninergic system in depression and schizophrenia includes the hypothesis of a disturbance in the transport systems of tryptophan and tyrosine from blood to brain. It would be interesting to know if blood cells may be used as a model for the central transport mechanisms of these amino acids. After an oral load, the in vivo distribution of L-tryptophan (50 mg/kg) was studied in the blood plasma, in the different blood cells and its binding to plasma albumin, in six healthy, seven schizophrenic and two depressive subjects. In all the compartments studied, tryptophan reached a peak, 1--2 hours after the load. Before and after the load, the variation of the tryptophan concentration in the erythrocytes was parallel to the plasma free tryptophan, whereas the uptake of this amino acid was higher in leukocytes and thrombocytes than in erythrocytes. However, this model does not show differences between schizophrenic and normal subjects with regard to the transport of tryptophan and tyrosine in these cells.

Biological Transport, Active↗
PubMed1979

The influence of oral tryptophan on cortical evoked responses in normals and schizophrenics.

The cortical evoked responses to sensory stimulation were studied in order to evaluate the central effects of oral tryptophan in normals and schizophrenics. In the first study, seven volunteer male students were tested during four experimental sessions. Visual evoked responses to flashes were recorded at occiput and vertex, before and 1 1/2 hours after the ingestion of 35 mg/kg tryptophan in apple purée with 50 g glucose or placebo. Some significant modifications of evoked responses were observed after tryptophan ingestion: a decrease of amplitude and an increase of variability. The latencies were rather stable, presenting only minor modifications. From these results, corroborated by some data from literature, it may be supposed that tryptophan induces a decrease of arousal. In the second study, seven chronic schizophrenics and 6 volunteer controls were tested, using an analogous experimental design, however with some modifications: the tryptophan dose was increased to 50 mg/kg and administered in 200 ml of milk, instead of apple purée with glucose. The modifications of evoked responses recorded in the preceding study were no longer found. Probably, the substitution of milk for glucose resulted in an alteration of the transport of tryptophan across the blood-brain barrier. The blood parameters were rather similar in the two studies; therefore, the central effects of tryptophan did not parallel its blood levels.

Administration, Oral↗
PubMed1978

[Usefulness of the immunoglobulin-albumin ratio compared to electrophoresis in the diagnosis of multiple sclerosis].

The results obtained with gel electrophoresis on CSF samples of multiple sclerosis patients are compared with measurements of CSF IgG indexes (IgG/alb and IgG/total protein). The correlation between these parameters is good, provided the upper normal limit of the IgG/alb index is over 35% and an "overlapping" zone between 21 and 35% is introduced where the IgG/alb index has not the same diagnostic value.

Adult↗