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Biomedical subjects

T Jahn

Publications and source records attributed to T Jahn.

22 records · Page 2Linked to original sources
PubMed1996

Correction of interleukin-2 receptor function in X-SCID lymphoblastoid cells by retrovirally mediated transfer of the gamma-c gene.

X-SCID, the most common form of human SCID, is due to mutations in the common gamma chain gene (gamma-c) that encodes an essential component of the cytokine receptors for interleukin-2 (IL-2), IL-4, IL-7, IL-9, and IL-15. Activation of the Janus family tyrosine kinases Jak1 and Jak3 is necessary for appropriate signalling through the IL-2 receptor (IL-2R). Neither Jak1 nor Jak3 was phosphorylated after IL-2 stimulation of an Epstein-Barr virus-transformed cell line (LCL) from an X-SCID patient with a gamma-c null mutation. However, we now show that appropriate IL-2R function can be restored in an X-SCID LCL by transduction of a wild-type gamma-c gene. A retroviral vector, G1gamma-cSvNa, was constructed and produced in the PG13 packaging line. Transduced X-SCID LCL expressed the G1gamma-cSvNa transcript. IL-2 stimulation of the transduced cell line resulted in appropriate tyrosine phosphorylation of both Jak1 and Jak3. Thus, retroviral-mediated transduction of normal gamma-c can reconstitute downstream signalling through the IL-2R in X-SCID cell lines, suggesting that gene therapy may be a treatment for this disease.

B-Lymphocytes↗
PubMed1996

Monitoring of task performance during functional magnetic resonance imaging of sensorimotor cortex at 1.5 T.

Functional magnetic resonance imaging (fMRI) has found widespread clinical interest. Difficulties in clinical use of the fMRI technique arise, considering the lack of knowledge about activation task performance. This accounts especially for sensorimotor activation studies, in which performance of the sensorimotor activation task is-if at all-usually rated visually by subjective or semiquantitative methods (i.e., defining categories of performance such as neurological soft signs scales). Recently, instrumental methods for the measurement and analysis of motor performance have been developed. Pronation/supination (hand rotation) movement was shown to be an easily measurable and promising motor task. We have adapted a mechanic device (pronation/supination device, PSD) to monitor motor performance during the fMRI experiment. In a feasibility study, an investigation of fMRI activation strength dependence of sensorimotor cortices and supplementary motor area upon task frequency (25, 50, and 75 cycles/min) was carried out on 10 right-handed healthy volunteers. Furthermore, the authors report the observation of stimulus-induced activation changes in the cerebellum during pronation/supination movement.

Hand↗
PubMed1993

Relationship between crossover and modality shift effects in sequential reaction time performance of schizophrenic patients.

On the basis of reaction time measurement, two well-known experimental indicators of attentional dysfunctions in schizophrenia were studied. These are the crossover effect (COE), induced by alternating preparatory intervals, and the modality shift effect (MSE), induced by alternating stimulus modalities. For the first time, the relationship between these indicators was examined. Correlations of both indicators with clinical variables such as psychopathology, subjective complaints, duration of illness and medication were also analyzed. Subjects were 50 schizophrenic inpatients and 50 healthy controls, 21 women and 29 men in each group. While earlier results for COE and MSE were replicable, no correlation between the two was found, leading to the conclusion that they involve different aspects of attention not necessarily impaired to the same extent in all patients.

Adolescent↗