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Biomedical subjects

M Kase

Publications and source records attributed to M Kase.

At least 73 records · Page 4Linked to original sources
PubMed1986

Multisystem degeneration: drugs and square wave jerks.

We studied a 55-year-old woman with macrosquare wave jerks and macrosaccadic oscillations with a vertical component. The oscillations almost completely disappeared after administration of diazepam, clonazepam, thiamylal, or phenobarbital. A disorder of GABAergic tonic inhibitory system from the substantia nigra to superior colliculus probably plays an important the pathogenesis of these abnormal ocular movements. role in the pathogenesis of these abnormal ocular movements.

Clonazepam↗
PubMed1986

Quantitative analysis of the oculocardiac reflex by traction on human extraocular muscle.

The oculocardiac reflex was quantitatively studied in 15 patients with strabismus. The reflex was observed in all patients when the medial rectus and inferior oblique muscles were stretched; the medial rectus muscle had a lower threshold than the inferior oblique. Bradycardia was evoked in 7 of the 15 patients when the lateral rectus was tractioned with tensions of 50 g and 600 g. The oculocardiac reflex was a graded phenomenon as a function of tension applied to the extraocular muscles. As tension was increased, bradycardia occurred rapidly and became deep. Systemic administration of atropine prevented completely the bradycardia from occurring. The results suggest that the response of the extraocular muscles to stretch are critically mediated through a polysynaptic path to the heart, resulting in suppression of the heart rate.

Arrhythmias, Cardiac↗
PubMed1986

Saccade-related activity of periaqueductal gray matter of the monkey.

Single unit activity was recorded extracellularly from the periaqueductal gray matter (PAG) and the superior colliculus of three monkeys during spontaneous saccades and fixation. Most saccade-related cells were found in the dorsal and lateral regions of the PAG and they paused with saccades. The pause preceded the onset of saccades by 34.5 +/- 6.8 msec (n = 31). In 90% of the 31 PAG cells, the saccade-related modulation in activity occurred in all directions. There was a linear relationship between pause duration and saccade duration with correlation coefficients larger than 0.70 in most cells. Superior colliculus cells showed bursts preceding onset of saccades. The lead times averaged 25.3 msec (n = 35). There was no linear relationship between burst duration and saccade duration. These results suggest that the dorsal and lateral regions of PAG play an important role in the saccadic system, probably through long lead burst units in the deep layer of the superior colliculus and/or pontine reticular formation.

Animals↗
PubMed1985

Effects of bromocriptine on parkinsonism. A nation-wide collaborative double-blind study.

The effects of bromocriptine in patients with Parkinson's disease manifesting various problems in levodopa therapy were tested in a double-blind manner with the collaboration of 59 institutions. The slow and low principle was in part adopted. Either bromocriptine or placebo was added to levodopa. Twenty-nine % of the bromocriptine-treated patients (n = 108), in contrast to 14.8% of the placebo-treated (n = 108), showed either marked or moderate improvement (P less than 0.05). Twenty to 37% improvement was noted in most of the symptoms studied in those treated with bromocriptine. The significant superiority of bromocriptine was also noted in the effects on wearing-off phenomena and frozen gait. No irreversible side effects were noted. It is concluded that bromocriptine is useful in patients who are manifesting various difficulties in levodopa therapy. Our results are comparable to those using higher maintenance doses. Dopamine antagonistic actions were not observed. This is unlike the case with experimental animals.

Bromocriptine↗
PubMed1985

Macrosaccadic oscillation, saccadic dysmetria and motor error in spinocerebellar degeneration.

The macrosaccadic oscillation was analyzed quantitatively in a 31-year-old man with spinocerebellar degeneration, using DC electrooculogram. Over a follow-up period of one year the macrosaccadic oscillation changed into saccadic dysmetria where square oscillations were suppressed during fixation and occurred only after visually guided saccades. The initial movements in the oscillation followed the main saccades with a mean latency of 147.6 msec. When a saccade showed an overshoot, a fast movement occurred in the opposite direction, and with undershoot of the saccade, the fast movement occurred in the same direction as that of the saccade. Furthermore, the amplitudes of the oscillation had a close correlation with those of the motor error, ie, the difference in the amplitudes between the target displacement and saccade. The results suggest that square oscillations in the macrosaccadic oscillation and saccadic dysmetria may be caused by an elevation of the gain in the corrective saccadic system.

Adult↗
PubMed1984

Effect of aging on the accuracy of visually guided saccadic eye movement.

Changes in oculomotor behaviors with aging were studied in normal young and elderly subjects. Saccadic eye movements induced by presentation of a visual target were analyzed. Elderly subjects commonly showed an elongation of the time to locate the target, accompanied by an increase in reaction times (mean increase, 100 ms) and a decrease in saccadic velocities. The decrease in the velocity was particularly notable when a large-amplitude saccade was executed. In spite of the slowed motor responses, most elderly subjects preserved the function necessary to execute a correct saccade toward the visual target. The saccadic slowing was accompanied by an increase in saccade duration. Although a longer time was necessary for elderly subjects to locate the target, the accuracy of the initial saccades was not different from that of young subjects. One group of elderly subjects showed extremely long reaction times. These subjects, displaying no abnormal neurological symptoms, were not able to locate the visual target with initial saccades. They had to execute multistep saccades typically seen in patients with degenerative neurological diseases.

Adult↗
PubMed1984

Pupillary light reflex in amblyopia.

The pupillary light reflex of 15 strabismic and anisometropic amblyopes, and eight subjects who had recovered from functional amblyopia was studied by using an infrared electropupillogram. Ten of the fifteen amblyopes had significantly longer latencies of contraction when the amblyopic eyes were stimulated than when the normal eyes were stimulated. However, there was no relationship between the delay in pupillary light reflexes and reduced visual acuity of amblyopic eyes. The amplitudes and maximum velocities of the contraction were not altered significantly in amblyopic and normal eyes. All of the subjects who had recovered showed no significant difference of the latencies of the pupillary responses to stimulation between normal and amblyopic eyes. These findings indicate that a retinal mechanism in amblyopic eyes may be responsible for the abnormally long pupillary light reflex latency.

Adolescent↗
PubMed1982

Pachymeningitis cervicalis hypertrophica.

Presented here is an autopsy case of pachymeningitis cervicalis hypertrophica. A 77-year-old female had the initial symptoms of cervical radiculopathy which terminated in the syndrome of spinal cord transection. Prior to the onset of radiculopathy, the patient had been admitted to the hospital because of a fever and had been shown to have granulomatous sinusitis. Autopsy revealed chronic granulomatous pachymeningitis of the cervical spinal cord, the lesion being mostly restricted to this region. From histopathologic similarities, the extension of sinusitis to cervical pachymeningitis was assumed, but this was not confirmed. An attempt to discover the causative micro-organisms was unsuccessful. The possibility of a limited form of Wegener's granulomatosis could be excluded in view of the absence of true angiitis. Corresponding to the levels of pachymeningitis, the spinal cord was also severely damaged, which was principally due to circulatory disturbance as a result of pachymeningitis.

Aged↗
PubMed1980

Discharges of Purkinje cells and mossy fibres in the cerebellar vermis of the monkey during saccadic eye movements and fixation.

1. Discharges of Purkinje cells and of presumed mossy fibres were extracellularly recorded from vermal lobules VI and VII of two monkeys during saccadic eye movements and fixation. Among the units showing changes in activity in relation to either saccades or eye position, eighty-four units were identified as mossy fibres and ninety-one units were Purkinje cells.2. Based on the discharge patterns associated with saccades, mossy fibre units were classified into long-lead burst, burst, and burst-tonic units. The long-lead burst units (twenty-eight units) started firing long before the saccades, the discharge consisting of a prelude (average lead time: 160 msec) and a burst (average lead time: 16 msec). In twenty-two units the saccade-related bursts showed a directional preference. The burst units (thirty-seven units) started firing slightly before the saccade onset (average lead time: 7.4 msec) and thirteen units showed directional preference. The bursts in burst-tonic units (thirteen units) had an average lead time of 0.2 msec.3. Among the ninety-one Purkinje cells, eighty-eight cells showed bursts associated with saccades. Three units paused for all directions of saccades.4. Seventy-one units out of the eighty-eight burst Purkinje cells showed bursts beginning approximately at the saccade onset (average lead time: 0.6 msec) and lasting throughout the saccade. The durations of bursts and saccades were highly correlated (correlation coefficients ranging from 0.70 to 0.88).5. In the remaining seventeen burst Purkinje cells, the bursts followed the saccade onset (average delay: 32 msec). The bursts started approximately 40 msec before the end of a saccade and persisted on the average 70 msec after its completion. Peak firing rate occurred with a close temporal relation to the end of the saccade.6. The tonic activity in nineteen mossy fibres and five Purkinje cells changed with eye positions. In the nineteen mossy fibres, there were thirteen burst-tonic and six tonic units. The activity in the five Purkinje cells was a linear function of horizontal eye position.

Action Potentials↗