Dorsal root potentials: effects of acoustic and visual stimuli.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
N S Chu
Publications and source records attributed to N S Chu.
ECG changes resulting from cerebral stimulation. III. Action of diphenylhydantoin on arrhythmias.
Explore the source record for details and available documents.
Animals↗
Brainstem auditory evoked potentials in hepatic encephalopathy.
Brainstem auditory evoked potentials were obtained from 30 patients primarily with viral hepatitis to determine the functional status of the brainstem in hepatic encephalopathy. The patients were divided into four groups: Group 1 with compensated hepatic diseases; Group 2 with hepatic failure but no hepatic encephalopathy; Group 3 with Grade 1 or 2 hepatic encephalopathy, and Group 4 with Grade 3 or 4 hepatic encephalopathy. The brainstem auditory evoked potential central conduction times (I-V interval) of four patient groups were not significantly different from that of the age-matched control group. The present data suggest that the brainstem auditory pathways remain undisturbed in hepatic encephalopathy.
Adult↗
Effects of Betel chewing on the central and autonomic nervous systems.
Betel chewing has been claimed to produce a sense of well-being, euphoria, heightened alertness, sweating, salivation, a hot sensation in the body and increased capacity to work. Betel chewing also leads to habituation, addiction and withdrawal. However, the mechanisms underlying these effects remain poorly understood. Arecoline, the major alkaloid of Areca nut, has been extensively studied, and several effects of betel chewing are thought to be related to the actions of this parasympathomimetic constituent. However, betel chewing may produce complex reactions and interactions. In the presence of lime, arecoline and guvacoline in Areca nut are hydrolyzed into arecaidine and guvacine, respectively, which are strong inhibitors of GABA uptake. Piper betle flower or leaf contains aromatic phenolic compounds which have been found to stimulate the release of catecholamines in vitro. Thus, betel chewing may affect parasympathetic, GABAnergic and sympathetic functions. Betel chewing produces an increase in heart rate, blood pressure, sweating and body temperature. In addition, EEG shows widespread cortical desynchronization indicating a state of arousal. In autonomic function tests, both the sympathetic skin response and RR interval variation are affected. Betel chewing also increases plasma concentrations of norepinephrine and epinephrine. These results suggest that betel chewing mainly affects the central and autonomic nervous systems. Future studies should investigate both the acute and chronic effects of betel chewing. Such studies may further elucidate the psychoactive mechanisms responsible for the undiminished popularity of betel chewing since antiquity.
Animals↗
Motor evoked potentials with magnetic stimulation: correlations with height.
The relationship between height and motor evoked potentials (MEPs) was studied in 52 healthy young subjects. Evoked responses from the abductor digiti minimi and tibialis anterior muscles were obtained following magnetic stimulation over the vertex and the cervical and lumbar regions. The latencies of MEPs were highly correlated with height. The conduction time from the motor cortex to the lumbar region was also correlated with height, but that from the motor cortex to the cervical region was not. It is concluded that height is an important variable in defining the MEP normality.
Adolescent↗
Effects of ethanol on Purkinje cells recorded from cerebellar slices.
The effects of ethanol on rat cerebellar Purkinje cells were studied using brain slice preparations. The spontaneous activity of Purkinje cells exhibited either steady or cyclic firing patterns. The steady units were generally inhibited by ethanol, but some units were excited by low doses. The cycling units showed a dose-related decrease in firing rate and the duration of cyclic firing. The data indicate that ethanol in concentrations which produce behavioral effects is primarily inhibitory to cerebellar Purkinje cells.
Action Potentials↗
Somatosensory and brainstem auditory evoked potentials in alcoholic liver disease with and without encephalopathy.
Median somatosensory and brainstem auditory evoked potentials (SEP and BAEP) were studied in chronic alcoholics with and without complications of alcoholic liver disease. The alcoholics were divided into 4 groups: Group 1 with minimally abnormal liver function tests; Group 2 with hepatic failure; Group 3 with mild to moderate hepatic encephalopathy; and Group 4 with severe encephalopathy. A control group consisted of age-matched normal subjects. In the alcoholic groups, BAEPs showed a significant prolongation in the latencies of peaks III to VI and interpeaks I-III, III-V, and I-V. The peak latency prolongation was associated with a reduction in all peak amplitudes. In median SEPs, the cervical N13 and cortical N20 latencies were significantly delayed in the alcoholic groups. The amplitude of all cortical SEP components within 150 msec analysis time was also significantly reduced. In addition, the alcoholic groups had slowing in median nerve conduction and prolongation in central conduction time (N13 to N20 interpeak latency). In both BAEPs and SEPs, there were no differences in the peak amplitude and the peak latency among the alcoholic groups except for the late cortical SEP components which showed progressive prolongation and eventual absence from Groups 2 to 4. The present data indicate that chronic alcoholics have subclinical dysfunction in the central somatosensory and brainstem auditory pathways irrespective of the complications of alcoholic liver disease. However, the late components of the cortical SEPs can be affected in hepatic failure and hepatic encephalopathy.
Adult↗
Responses of midbrain dorsal raphe neurons to ethanol studied in brainstem slices.
The effects of ethanol on midbrain dorsal raphe (DR) neurons were studied using the brainstem slice preparations. Ethanol in low doses (100 mg% and 200 mg%) exerted more excitation than inhibition on DR cells. Higher doses of ethanol produced inhibition in the majority of DR neurons. The present data indicate that the effects of ethanol were biphasic with low concentrations tending to excite and high concentrations to inhibit DR neurons.
Action Potentials↗
Sympathetic response to betel chewing.
Explore the source record for details and available documents.
Adult↗
Late CT manifestations in spontaneous lobar hematoma.
PURPOSE: The purpose of this work was to determine the late CT manifestations of spontaneous lobar hematoma. METHOD: Serial CT studies were performed in 75 cases. The initial study was done during the acute stage of stroke, and the subsequent one was performed at least 6 months later. RESULTS: There were 20 cases (27%) with no trace of previous hemorrhage, 14 (19%) with a slit cavity, 11 (15%) with a small round cavity, 20 (27%) with pseudoinfarct, 8 (11%) with ventricular deformity but no residual cavity, and 2 (3%) with only calcification at the site of the hemorrhage. CONCLUSION: Our data show that the typical residual slit was relatively uncommon in lobar hematomas and that, depending on their size, hematomas would disappear, reduce to a small cavity, or form a pseudoinfarct.
Adult↗
Long-term ambulatory cassette EEG with sphenoidal recording in complex partial seizures.
Long-term ambulatory cassette EEG with sphenoidal recording (A/EEG-SP) was performed in 51 patients. Group A comprised 31 patients with a clinical diagnosis of complex partial seizures (CPS), and group B comprised 20 patients suspected of having CPS. In group A, detection of temporal spikes was 27% by routine EEG (R/EEG), 72% by sphenoidal EEG (SP/EEG), 27% by A/EEG with temporal chain montage, and 91% by A/EEG-SP. The highest yield achieved by A/EEG-SP as compared with other EEG recordings was documentation of spontaneous seizures of temporal lobe origin. The detection rate of spontaneous seizures by A/EEG-SP was approximately 30%, and the focal or regional onset of seizures could be determined in 60% of patients. In group B, detection of temporal spikes was 11% by R/EEG, 18% by SP/EEG, and 30% by A/EEG-SP. Spontaneous seizures were recorded by A/EEG-SP in two patients (10%). Thus, A/EEG-SP was more effective than A/EEG in detecting interictal and ictal temporal discharges, and A/EEG-SP was superior to SP/EEG in documenting spontaneous seizures of temporal lobe origin.
Adolescent↗
Random mitotic segregation of mitochondrial DNA in MELAS syndrome.
We describe the heterogeneity of clinical features and molecular genetic characteristics of the probands and other members in two families with mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes (MELAS) syndrome. A point mutation at the 3243rd nucleotide position of mtDNA was found only in some of the maternal lineage members of the two families. Furthermore, the proportions of mutant mtDNA were varied and found only in some tissues of the individuals. Intriguingly, in some subjects, the mutant mtDNA was found in blood cells or hair follicles but was absent in muscles. The data do not support the notion of a selective advantage of wild-type mtDNA to rapidly replicating cells. We suggest that a rapid replicative segregation may occur in early embryogenesis.
Adolescent↗
Wilson's disease: resolution of MRI lesions following long-term oral zinc therapy.
A 28-year-old man with Wilson's disease developed neurological deterioration after a low-dose of d-penicillamine treatment for 2 weeks. He showed an akinetic rigid syndrome with generalized dystonia. Brain magnetic resonance images (MRI) on T2 and proton weighted images showed an increased signal intensity over the thalamus, basal ganglia and brainstem, especially the midbrain and pons. After treatment had been changed to zinc sulphate, the akinetic-rigid syndrome and dystonia were improved slowly in the following 4 years. Serial MRI studies showed a gradual resolution of the lesions. His current neurological status was almost normal except for dysarthria and mild intention tremor.
Administration, Oral↗