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J Zeitlhofer

Publications and source records attributed to J Zeitlhofer.

117 records · Page 7Linked to original sources
PubMedDate not supplied

Somatotopy of human hand somatosensory cortex as studied in scalp EEG.

We recorded somatosensory evoked potentials (SEPs) in scalp EEGs during stimulation of the median nerve, the ulnar nerve and the individual digits in 3 normal subjects and in 1 epilepsy patient. In this patient we also measured SEPs from chronically indwelling subdural grid electrodes during electrocorticography (ECoG). We applied dipole modelling technique to study the 3-dimensional intracerebral locations and time activities of the neuronal sources underlying stimulation of different peripheral receptive fields. The sources underlying median nerve SEPs were located an average of 10.8 mm lateral inferior to those underlying ulnar nerve SEPs. Digit SEP sources showed a somatotopic arrangement from lateral inferior to medial superior in the order thumb, index finger, middle finger, ring finger and little finger, with some overlap or reversal for adjacent digits. The average distance between thumb and little finger was 12.5 mm. Thumb, index finger and middle finger were clustered around median nerve cortical representation, whereas ring finger and little finger were arranged around ulnar nerve cortex. In the epilepsy patient, the source localizations obtained in scalp EEGs showed good agreement with those on ECoGs. We conclude that SEPs recorded in scalp EEGs can be used to study functional topography of human somatosensory cortex non-invasively.

Adult↗
PubMedDate not supplied

Collagenase-induced experimental arthritis.

Rabbits were injected intraarticularly three times with 0.5 ml of 10, 50 or 100 mg% purified rheumatoid synovial collagenase or with identical amounts of trypsin. 18 hours after the last injection the collagenase-injected animals showed distinct cellular exudation into the synovial fluid and acute arthritis; one week later there was a decrease of the cell count in the synovial fluid and appearance of proliferative synovitis, while 3 weeks later there was no exudation and less chronic inflammation but distinct fibrosis of the synovium. A direct action of collagenase on the connective tissue components would seem to be responsible for these changes. No pathologic alteration of the cartilage was observed. Trypsin-injected control animals showed negligible cellular exudation and no pathologic alteration of the synovium.

Animals↗
PubMedDate not supplied

Acute autoimmune collagen-induced arthritis in rabbits.

Three groups of rabbits were investigated: I. 9 rabbits, immunized with rabbit collagen type I, received 1 intraarticular injection of same antigen in the right knee, and control preparations in the left knee. II. 4 rabbits, immunized with calf collagen type I, received the same intraarticular injections as in group I. III. 2 non-immunized rabbits received also the same intraarticular injections. Synovial fluid and synovium were obtained in all groups 18 hours after intraarticular injection. Knee-joints of all animals immunized and challenged intraarticularly with rabbit collagen showed strong cellular exsudation (mean 1.800 X 10(3) cells,) in contrast to control joints (mean 21 to 484 X 10(3) cells). Histologic investigation of synovium of group I animals showed in rabbit collagen injected knees in contrast to controls, vascular reactions with enlargement of small vessels, thikening of endothelial cells, perivascular infiltration and aggregation of polymorphonuclears in lumen of vessels. Intraarticular injection of rabbit collagen in calf collagen immunized rabbits, induced a limited cellular exsudation, (mean 670 X 10(3) cells) which was lower than in rabbit collagen immunized animals, however also more pronounced than in control joints. Whilst results after intraarticular injection of rabbit collagen in rabbit collagen immunized animals are interpreted as early signs of autoimmune arthritis, results after intraarticular injection of rabbit collagen in calf collagen immunized animals are regarded as milder symptoms of synovitis induced by crossreactivity of antigens.

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