Search PubMed⌕ Search

Biomedical subjects

H Narabayashi

Publications and source records attributed to H Narabayashi.

At least 109 records · Page 6Linked to original sources
PubMed1983

Pharmacological basis of akinesia in Parkinson's disease.

Akinesia, the core symptom of the parkinsonism, which is the term having been used routinely in daily practice of neurology in describing the specific motor disturbance in parkinsonian patients, is not well defined in sense of its generating mechanism. The author tried to analyze this concept from physiological and pharmacological standpoint and classified into three subgroups, i.e. slowness of movement, poverty of movement and difficulty in initiating repetitive movement. These three groups are interpreted as due to deficiency either of DA or of NE, the former being related to the slowness of movement and the poverty of movement and the latter to the freezing symptoms in the later stage of illness. Parkinson's disease now should better be understood as the result of deficiency of several catecholamine metabolites due to chains of enzymic error, and not only of DA.

Brain↗
PubMed1982

Alteration of inner-membrane components and damage to electron-transfer activities of bovine heart submitochondrial particles induced by NADPH-dependent lipid peroxidation.

We investigated the changes of the inner-membrane components and the electron-transfer activities of bovine heart submitochondrial particles induced by the lipid peroxidation supported by NADPH in the presence of ADP-Fe3+. Most of the polyunsaturated fatty acids were lost as a result of the peroxidation, and phospholipids were changed to polar species. Ubiquinone was also modified to polar substances as the peroxidation proceeded. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis showed the disappearance of 27000-Mr and 30000-Mr proteins and the appearance of highly polymerized substances. Flavins and cytochromes were not diminished, but the respiratory activity was lost. The reactions of NADH oxidase and NADH-cytochrome c reductase were most sensitive to the peroxidation, followed by those of succinate oxidase and succinate-cytochrome c reductase. Succinate dehydrogenase and duroquinol-cytochrome c reductase were inactivated by more extensive peroxidation, but cytochrome c oxidase was only partially inactivated. NADH-ferricyanide reductase was not inactivated. The pattern of the inactivation indicated that the lipid peroxidation affected the electron transport intensively between NADH dehydrogenase and ubiquinone, and moderately at the succinate dehydrogenase step and between ubiquinone and cytochrome c.

Animals↗
PubMed1981

Biopterin in human brain and urine from controls and parkinsonian patients: application of a new radioimmunoassay.

Total biopterin concentrations in the post-mortem human brain (caudate nucleus) and in the urine of controls and parkinsonian patients were measured by a newly developed radioimmunoassay. There was good correlation between the total biopterin level and tyrosine hydroxylase activity in the human brain. Biopterin concentrations in the caudate nucleus were greatly reduced in parkinsonian patients. In contrast, the reduction of urinary biopterin in parkinsonian patients was slight and not statistically significant, as compared with normal controls.

Aged↗
PubMed1980

Clinical analysis of akinesia.

Symptoms called akinesia in movement are analysed and classified into three groups. The first is that secondary to existence of marked rigidity of muscles and the second is that due to striatal dopamine deficiency, which simply be interpreted as "lack of movement". The third is freezing or festination in quick repetitive movement especially in gait, speech and handwriting, for which 1-Dopa therapy has no influence. Specific difficulty in the latter condition is found in the rhythm formation of repetitive movements when repetition is over 2 Hz, which the author named "hastening phenomenon converging into 5 Hz". However, the neural mechanism and pathology under the third group of akinesia is still not known. In most of the parkinsonian patients, it is considered that all three groups of akinesia are mixed together with variety of grade. Careful observations on the changes of clinical pictures through the course of 1-Dopa therapy and of stereotaxic surgery provided the analysis of so-called akinesia as described.

Dopamine↗
PubMed1980

From experiences of medial amygdalotomy on epileptics.

This paper does not present any new cases. From the long-term follow-up study of the cases operated by the stereotaxic medial amygdalotomy, the progressive worsening in clinical pictures of the chronic epileptics, such as changes of pattern of seizures, aggravation of seizure tendency and of emotional and behaviour problems, were found to be parallelly improved. The reason of such beneficial changes is discussed and the possible participation of the limbic structures is suggested.

Adolescent↗
PubMed1980

Effects of postural change of the shoulder on EMG reaction time of triceps brachii.

Postural dependence of electromyographic reaction time (EMG-RT) of triceps brachii in normal subjects was examined at neutral (N) and facilitating (F) positions. EMG-RT was faster at F than at N; moreover, the slower one's EMG-RT, the larger the difference of EMG-RTs. F position of arms causes the shifting of EMG-RT through two biasing systems. The action of one system arises from either arm and acts on both arms, as the facilitation and its intensity depend on one's EMG-RT. The other system arises from one arm, and facilitates the ipsilateral arm but inhibits the contralateral arm; its intensity is independent of one's EMG-RT. The amount of the shift is determined by the added contribution of those two actions.

Adolescent↗
PubMed1980

Importance of microstereoencephalotomy for tremor alleviation.

Application of the microelectrode technique in human stereotactic surgery, which is especially important for tremor control, is now routine for the procedure in our surgical theater. Neurons responsible for tremor generation can very delicately and exactly be identified within the ventralis intermedius nucleus (Vim) of the thalamus, which automatically determines the location of the minimum required thermocoagulation lesion to abolish tremor. Neurons with rhythmic burst discharges, which are synchronus in phase to the peripheral tremor, are organized in delicate somatotopic fashion within the Vim. Electrical stimulation of the neuron area through this microelectrode usually inhibits tremor of the corresponding area and a small thermocoagulation lesion, usually 3 mm in diameter, permanently abolishes tremor. These three findings, i.e., existence of rhythmic bursts, effect of the stimulation and surgical lesion, are the same in parkinsonian tremor, postural tremor and intention tremor. Physiological interpretation of different types of tremor will be proposed. In the cases of idiopathic neck tremor, a single Vim neuron corresponded to four neck muscles, i.e., bilateral sternocleidomastoid muscle (SCM) and bilateral posterior neck muscles, and most markedly to the controlateral posterior neck muscle and the ipsilateral SCM. Instrumentation of microstereoencephalotomy is also explained.

Aged↗
PubMed1980

Postural dependence of reaction time after a VL thalamotomy.

Postural dependence of the EMG-RT of the triceps brachii muscles was measured in 68 parkinsonian patients of which 38 underwent a ventrolateral thalamotomy. A thalamotomy did not affect patients' EMG-RT per se, but it changed the postural dependence of the EMG-RT. After left thalamotomy the position changes of both shoulders did not influence the EMG-RT of the right triceps, and after right thalamotomy the position change of the left shoulder had no influence on the EMG-RT of both triceps. As for the sensorimotor function, it is assumed that the right thalamus has bilateral control on the input system and the left thalamus has bilateral control on the output system.

Adult↗