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Biomedical subjects

R C Chen

Publications and source records attributed to R C Chen.

At least 91 records · Page 5Linked to original sources
PubMed1985

Changes in motor unit action potential parameters in monopolar recordings related to filter settings of the EMG amplifier.

We studied the effect of different electromyographic amplifier settings on various parameters of motor unit potentials (MUPs) as recorded by the monopolar needle. Of the four filter settings used--2Hz-10kHz, 20Hz-10kHz, 20Hz-2kHz and 500Hz-10kHz--2Hz-10kHz yielded longest duration recordings. Reductions of all parameters of the MUP except for phases and turns were demonstrated with the 500Hz-10kHz filter. No significant differences were noted between recordings obtained with 20Hz-10kHz and 20Hz-2kHz filters. Frequencies below 500Hz were more significant in determining the various parameters of the MUP than were those above 2kHz. Most suitable filter settings for recording MUPs were 2Hz-10kHz and 20Hz-10kHz. Measurements of MUPs were shown to be specific for a given filter setting.

Action Potentials↗
PubMed1984

Acupuncture on experimental epilepsies.

The therapeutic effect of acupuncture on epilepsies was evaluated in 4 experimental models. 24 acupuncture points were tried. In electroconvulsive threshold model, square wave electrical stimulus of 0.2 msec and 6 Hz was applied through a pair of cotton electrodes at the cornea of mice for 3 sec. The stimulus intensity to induce stun reaction of the mouse was compared. In 86 control animals, the stimulus threshold was 0.70 +/- 0.22 mA. In the acupuncture treated group (N = 80), the threshold was 0.75 +/- 0.14 mA. In maximal electroshock model, the stimulus parameters were 60 Hz, 0.4 sec and 75 mA. The tonic extensor response of the hindlimbs of the mice was observed. 75.7% of the 115 control mice and 77.5% of the 80 acupuncture treated mice were observed to have tonic extensor response. In the focal cortical penicillin model, penicillin was applied at the subpial space over the exposed cortex of 24 cats. After the appearance of repeated spikes in ECoG, acupuncture was performed. In 175 trials the interictal spikes were decreased in 16 times, increased in 82 times. In 99 trials during seizures, the ictal activity was decreased in 4 times, increased in 79 times. In the intravenous penicillin model, high dose penicillin (1,000,000-1,500,000 U/kg) was given to 20 cats. It induced repetitive spikes and frequently even seizure discharges in EEG. Acupuncture was then tried. In 192 instances, acupuncture reduced the spikes in 13, increased the spikes in 103 times. In 74 trials during seizures, the ictal activity was suppressed in 4 times and aggravated in 66 times.(ABSTRACT TRUNCATED AT 250 WORDS)

Acupuncture Therapy↗
PubMed1981

[The correlation between autoantibodies and leukocyte migration index in myasthenia gravis (author's transl)].

Sera from 38 myasthenic patients and 15 non-myasthenic controls were surveyed by indirect immunofluorescence technique for reactivity against skeletal muscle, nuclei and mitochondria. Cell-mediated response to purified muscle antigen was detected by leukocyte migration inhibition assay. The positive rates for antiskeletal antibody (ASMA), antinuclear antibody (ANA), and antimitochondrial antibody (AMA) were 50%, 10.5% and 0%, respectively, in the myasthenic patients, and were 13.3%, 6.6% and 0%, respectively, in the controls. The mean titer of antiskeletal muscle antibody was 1:9.8 in the myasthenic patients and 1:1.8 in the controls. Both the positive rate and the mean titer of ASMA were higher and the migration index was lower in the patients with thymoma or thymic hyperplasia. To the contrary, among the group treated with corticosteroids, the correlation of the positive rate and mean titer of ASMA to migration index revealed a marginally significantly negative linear correlation (y = -0.72 chi + 84.69, r = -0.80, 0.1 greater than p greater than 0.05). This meant that the higher positive rate of ASMA was usually associated with the lower migration index. The facts of higher positive rate of ASMA in myasthenic patients and its negative correlation to migration index gave supportive evidence for a possible role of ASMA in the pathogenesis of myasthenia gravis.

Adolescent↗