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111.
A new method of time-frequency analysis, based on the Matching Pursuit (MP) algorithm, was used to extract and quantify EEG 'driving' or frequency-following responses produced in human primary somatosensory cortex (SI) by 33 Hz vibrotactile stimulation of the right index fingertip in a single subject. EEG signals were recorded from a 5 x 5 array of electrodes centered over the left hand area, time-locked to repeated presentations of four vibratory stimulus amplitudes. The MP algorithm was used to decompose the edited and and filtered EEG signals into waveforms selected from a large and redundant dictionary. Statistical discrimination of the vibratory stimulus amplitudes was then readily achieved in terms of trial-by-trial measures of response amplitude constructed in automated fashion from the calculated MP parameters. The results were orderly and physiologically coherent, and potentially open the way to correlation of psychophysical magnitude estimates with measures of neurophysiological response on a trial-by-trial basis. The approach developed here appears well suited to detection and characterisation of time dependent or transient target signals embedded in a noisy background. 相似文献
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AJ Van Oosterhout B Van Esch G Hofman CL Hofstra I Van Ark FP Nijkamp ML Kapsenberg HF Savelkoul FR Weller 《Canadian Metallurgical Quarterly》1998,19(4):622-628
Microelectrode recording methods for stereotactic localization of the subthalamic nucleus (STN) and surrounding structures are described. These methods accurately define targets for chronic deep brain stimulation in the treatment of Parkinson's disease. Mean firing rates and a burst index were determined for all recorded neurons, and responses to active and passive limb and orofacial movements were tested. STN neurons had a mean firing rate of 37+/-17 Hz (n = 248) and an irregular firing pattern (median burst index, 3.3). Movement-related activity and tremor cells were identified in the STN. Ventral to the STN, substantia nigra pars reticulata neurons had a mean rate of 71+/-23 Hz (n = 56) and a more regular firing pattern (median burst index, 1.7). Short trains (1-2 seconds) of electrical microstimulation of STN could produce tremor arrest but were not found to be useful for localization. Compared with data from normal monkeys our findings suggest that STN neuronal activity is elevated in Parkinson's disease. 相似文献
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More than 50% of patients with chronic renal failure will be suppressed in their cell-mediated immune response to 2,4-dinitrochlorobenzene (DNCB). This applies in renal failure attributable to juvenile onset diabetes as well as other types of end stage renal disease. Significantly better kidney survival of both living related and cadaver grafts is seen in diabetic patients who are non-responsive to DNCB. Twelve-month kidney survival for DNCB-negative patients receiving living related allografts is 71% compared with 25% for DNCB-positive patients. Twelve-month kidney survival in cadaver recipients is 39% in DNCB-negative compared with 9% for DNCB-positive patients. Successful second grafts were done in DNCB-negative diabetic patients, however, all second grafts in DNCB-positive patients failed in less than 3 months. DNCB skin test reactivity as a measure of cell-mediated response is a valuable predictor of immunological outcome of transplantation in patients whose renal disease results from juvenile onset diabetes. Patient survival in DNCB nonresponders is nearly twice that of DNCB responders. Differences in outcome following transplantation could not be accounted for by HLA disparity, transfusion history, or other variables known to effect transplant outcome. Kidney and patient survival in DNCB-positive diabetic patients receiving either cadaver or living related allografts is sufficiently low as to identify them as a subpopulation of renal failure patients who should be treated by dialysis, or selected for special protocols which might provide immunological manipulation prior to transplantation to improve their treatment outcome. 相似文献
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FG Middleton PF Jurgenson JP Utz S Shadomy HJ Shadomy 《Canadian Metallurgical Quarterly》1976,136(4):444-448
In 17 previously reported cases of cladosporiosis, no reliable therapy was described, and death occurred usually within one year of diagnosis. Pretreatment isolates from our two patients were inhibited by 6.2 mug/ml and 3.1mug/ml of flucytosine, respectively. Although both patients died, postmortem examination results showed that in one patient, the fungus had been eradicated. In the other patient, C trichoides that was isolated at postmortem examination was resistant to flucytosine treatment. 相似文献
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In 17 of 26 patients with extensive, symptomatic Paget's disease poor renal visualization was noted on bone scanning with 99mTc-diphosphonate. Renal function was normal in all patients. The intensity of the renal image proved to be inversely related to the extent and metabolic activity of the Pagetic process. This finding supports the hypothesis that in Paget's disease the balance between skeletal and renal extraction of circulating tracer amy be displaced in favor of the former. 相似文献
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