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Biomedical subjects

R Kwak

Publications and source records attributed to R Kwak.

At least 37 records · Page 2Linked to original sources
PubMed1983

[Moyamoya disease associated with persistent primitive trigeminal artery-Report of two cases].

Two cases of Moyamoya disease associated with persistent primitive trigeminal artery (PTA) are reported. Case 1: A 44 year-old man had sudden severe headache and found to have a subcortical hematoma in the left temporo-parietal lobe by CT-scans. Four vessel study revealed the right PTA and Moyamoya disease. Case 2: A 56 year-old woman suffered sudden severe headache and was diagnosed as subcortical hematoma in the right temporo-parietal lobe by CT scans. The left PTA and Moyamoya disease were revealed by four vessel study. In the previously reported 232 cases with PTA, we couldn't find out any case associated with Moyamoya disease. There are also no cases associated with Moyamoya disease in 93 cases of persistent primitive hypoglossal artery (PHA) whose vascular anomaly is essentially similar to that of PTA. In the 907 cases of Moyamoya disease collected by Japanese cooperative study, there were no cases in which PTA or PHA was associated by. The period when PTA or PHA disappears at the embryonic stage (5-14 mm) almost corresponds to the period (11-14 mm) in which the vascular state is similar to Moyamoya phenomena. From this point of view, two cases of Moyamoya disease associated with PTA suggest that there is a close relationship between Moyamoya disease and PTA. On the other hand, it seems that Moyamoya disease is associated with PTA by mere chance, because their combination is very rare and Moyamoya vessels changes frequently and dynamically, while PTA does not change.

Adult↗
PubMed1982

[Centro-median thalamotomy for central pain following stroke --its effectiveness and limits].

Centro-median thalamotomy was performed on 18 patients with central pain caused by cerebrovascular disease. Fourteen were males and four were females. Clinical diagnoses were thalamic pain in 17 cases including cheiro-orale syndrome in one case and phantom limb pain in one case. CT scans were performed on six recent cases. Four cases had a small low density sera in the thalamus. The other two cases had no remarkable findings. The target was 7.5-11.0 nm posterior to the middle point of the intercommissural line, 1.0 mm below-2.0 mm above that line and 5.5-10.0 mm from the midline. Unilateral lesion was made on 15 cases. Postoperatively, five cases had almost completely relief of pain and four cases had partial improvement. The duration of pain relief was, however, less than two months in four cases, and between three and seven months in four cases. One case had a pain free period for seven months. But, then, severe dysesthesia appeared. Six cases had no pain relief by unilateral lesion. Two cases had no pain relief by bilateral lesions. In the remaining case, unilateral lesion was effective for six months. Then lesion of opposite side was made, but the result was unsatisfactory. The durations from the onset of apoplectic attack to the occurrence of pain were between four months and three years in ten effective cases, and within three months in six among eight failed cases. Many surgical and medical treatments have been attempted for central pain. However, ideal method is still not appeared. Centro-median thalamotomy was effective for 56% of the patients with central pain. But in most of the cases, the duration of pain relief is about a half year at the longest. And may be, this is the limit of effectiveness of centro-median thalamotomy for central pain.

Adult↗
PubMed1982

[Factors affecting prognosis of thalamic hemorrhage (author's transl)].

The present study deals with the factors affecting the prognosis in the acute stage of 29 cases with hypertensive thalamic hemorrhage diagnosed by CT scan. It was thought that the following factors were significantly related to the outcome of the patients who were unable to lead daily life, remained in vegetative state or died. (1) Consciousness level was below 10 in the so-called 3-3-9 formula. (2) Bilateral Babinski's signs was observed. (3) Localization of the hematoma was all the thalamic nuclei type. (4) Hematoma volume was above 10 ml. (5) As for the size of hematoma, the maximum dimension of hematoma was over 30 or 35 mm, maximum width over 30 mm, maximum length over 25 mm and maximum height over 30 or 40 mm. (6) Ventricles were dilatated. It was seemed that the prognosis had no significant relationship with the age of the patients, the difference between left and right side of hematoma, with the presence or the absence of ventricular penetration of hematoma, and with the existence of midline shift. We thought that in the acute stage of hypertensive thalamic hemorrhage of the prognosis could be forecasted by neurological findings, accurate calculation of the hematoma volume and size, localization of hematoma and presence or absence of ventricular dilatation by CT scan.

Adult↗
PubMed1981

[Effects of bilateral mammillary bodies destruction on lever pressing for food reward in the rabbit (author's transl)].

Effects for continuous reinforcement (CRF) learning and differential reinforcement of low rate (DRL) learning for food in the rabbit by bilateral mammillary bodies destruction were examined with the Skinner box. There was no marked changes in general behavior, except a tendency to freezing by a sign of somebody and sounds. In CRF learning a delay in the start of bar pressing was thought to be due to a decrease in exploratory behavior and a decrease of the number of bar pressing may be due either to a delay of adaptation to a new environment, or to an impediment of learning by the decrease in rewarding effects. The acquisition of DRL learning was affected, but the retention of that was not. DRL learning has been generally remarked to be chiefly consisted of motivation and temporal discrimination. In our study, however, there was no remarkable changes in motivation itself and temporal discrimination was not affected at all. It was concluded that the impediment of acquisition depended upon a general decrease in cerebral rewarding effects.

Animals↗
PubMed1980

Hemodynamics in the anterior part of the circle of Willis in patients with intracranial aneurysms: a study of cerebral angiography.

Cerebral angiography revealed that hypoplasia of the A1 portion of the anterior cerebral artery is more frequent in patients with aneurysms of the anterior communicating artery than in those with aneurysms of other intracranial arteries. As for the hypoplasia of the A1, the angiographic findings corresponded to the surgical findings in 86.9% of all the patients. In patients with anterior communicating artery aneurysms, the incidence of hypoplasia of the A1 portion was about 3 times higher on the right side than on the left side.

Adolescent↗
PubMed1980

Anterior communicating artery aneurysms with associated anomalies.

In 296 cases with a single aneurysm of the anterior communicating artery (ACoA), fenestration or the presence of more than two ACoA's was observed in 17 cases (5.7%), and abnormal vessels of ACoA origin, such as a median artery of the corpus callosum, were observed in 13 cases (4.4%). As more than one anomaly was found in some of these cases, anomalies of the ACoA were found in total of 26 cases (8.8%). This occurrence rate was no higher than that observed in other cerebral aneurysm cases and in the control cases, which were reported previously. There was no significant increase of hypoplasia of the A1 portion if the ACoA aneurysm was complicated by other arterial anomalies.

Corpus Callosum↗
PubMed1980

Review of incompletely occluded surgically treated cerebral aneurysms.

Among the 837 cases of direct surgical treatment of single saccular aneurysms in our clinic from 1961 until September, 1975, postoperative angiograms were obtained in 578 cases and an investigation showed 41 had residual aneurysms. Of these, 19 were further treated by muscle wrapping or wrapping subsequent to treatment ofhe neck. Postoperative angiograms revealed residual aneurysms in 22 cases (3.8%) in which insufficient surgical treatment was performed.

Cerebral Angiography↗
PubMed1980

Afferent artery and the site of neck of anterior communicating aneurysms.

The relationship between the afferent artery and the site of aneurysmal neck and hemodynamics in the anterior part of the circle of Willis was investigated from surgical and angiographic findings in 213 patients with anterior communicating artery aneurysms. An afferent artery was limited to the dominant A1 in about 95% of them. The neck of an aneurysm was more than three times greater at the bifurcation of the dominant A1 and the anterior communicating artery than at the bifurcation of the non-dominant A1 and the anterior communicating artery.

Cerebrovascular Circulation↗
PubMed1980

[Electrical activity of the dorsal hippocampus during DRL learning in the rabbit (author's transl)].

The change of electrical activity of the dorsal hippocampus during differential reinforcement of low rate (DRL) learning was examined in six rabbits. Bipolar electrodes were implanted stereotaxically into the dorsal hippocampus (3 mm posterior to bregma, 4-4.5 mm lateral and 7-7.5 mm ventral from bregma). After completion of continuous reinforcement learning, the animals learned DRL on a 10 sec. schedule. Rhythmic theta waves (6-8 Hz, 0.6-1.5 mV) were predominant in the early sessions of the DRL schedule. With further sessions, regular theta waves decreased and desynchronized waves or slightly irregular theta waves increased especially during the 10 second waiting period. Contrary to the report of Bennett et al., synchronized waves were always seen from 1-2 sec. before lever-press until completing of lever-press. Moreover, these preceding synchronized waves became more pronounced and of higher frequencies (8-10 Hz.) as learning proceeded. These high frequency regular waves (alpha-bursts) were seen in 5.6-35.8% of reinforced lever-press in the 10th session, and 79.5-93.8% in the 60th session. Alpha bursts were sometimes seen after 8-9 sec. waiting in the later sessions, but never seen within five secs.. During the extinction of DRL learning, the occurrence rate of alpha-bursts on adequate but non-rewarded lever-pressing decreased. These results cannot be explained satisfactorily in terms of an association between synchronized waves and voluntary movement. Frequency increase was seen when rabbits expected reinforcement after waiting for about 10 sec. or more. These results indicate that frequency increase of hippocampal synchronized waves is seen in association with higher central processing, most likely with memory.

Alpha Rhythm↗
PubMed1979

The safe time limit of temporary clamping of cerebral arteries in the direct surgical treatment of intracranial aneurysm under moderate hypothermia.

Of 274 operated cases of cerebral aneurysm, temporary occlusion of the cerebral arteries was used in 215 cases (79%). Of the 215 cases, 177 (82%) showed no sequelae. The maximum safe time limit for temporary occlusion at the bilateral A1 portion of the anterior cerebral arteries was 48.5 min at 26 degrees C, 47 min at 27 degrees C, and 42 min at 28 degrees C; at the M1 portion of the middle cerebral arteries, it was 30 min at 26 degrees C, 35 min at 27 degrees C, 36 min at 27.5 degrees C, 40 min at 30 degrees C and 19 min at normothermia; and at the dominant A1 portion, in cases of hypoplasia at the contralateral A1 portion, it was 82 min at 26 degrees C, 86 min at 27.5 degrees C, and 63 min at 28 degrees C. Consequently, when performing direct surgery on aneurysms of the anterior communicating artery, unilateral clamping of the A1 portion prevents rupture during surgery and has the advantage of prolonging the occlusion time. Neurological sequelae may have been caused by the temporary occlusion of the cerebral artery in one case, and by the temporary occlusion or the surgical operation in six cases. Of the 22 fatal cases, only one was thought to be due to the temporary occlusion of the cerebral artery. Intermittent release of the clamping for 5 to 10 min is considered to be effective in prolonging the safe time limit of temporary clamping of the cerebral arteries in surgery of cerebral aneurysm under moderate hypothermia.

Adult↗
PubMed1979

Arrest reaction in man: motor arrest response by electrical stimulation of the deep structure of the cerebrum.

In spite of many reports of arrest reaction in animals, there are very few reports in man. During a therapeutic stereotactic operation we observed peculiar phenomena caused by electrical stimulation to the deep structure of the cerebrum. The electrical stimulation caused an interruption of counting and other motor actions, which could be resumed following release of stimuli. In almost all cases psychic confusion of memory disturbances were not observed. The head of the caudate nucleus and its adjacent white matter cause arrest reaction with the lowest threshold of 5 V; on the other hand, substantia medullaris lobi frontalis, radiatio corporis callosi and nucl. reticularis oralis of the thalamus caused arrest reaction with the highest threshold of 10--15 V. The arrest reaction that we observed is thought to be due to a direct effect on the head of the caudate nucleus, not due to secondary effects on the internal capsule and the motor fiber in the vicinity of the caudate nucleus. However, the possibility that the current spread to the motor fiber cannot be definitely ruled out.

Adult↗
PubMed1979

The correlation between hypertension in past history and the incidence of cerebral aneurysms.

The incidence of hypertension in past history was investigated in 811 cases of cerebral aneurysm. These cases were compiled from 1,000 cases of saccular aneurysm in which direct surgical operations for aneurysm were performed at our clinic during the period from June 1961 to September 1975. Of the 811 cases, 365 (45%) had hypertension in their past history; 185 (42.7%) out of 433 males and 180 (47.6%) out of 378 females. In the 5th decade of age, the incidence was significantly higher in the females than in the males, but no difference by sex was noted in other age groups. In the males from the 3rd to the 7th decade, the number of hypertensives increased significantly with advancing age, whereas in the females a significant difference was observed only between the 4th and 7th decades, the latter including more hypertensives. The incidence of hypertensives in the aneurysm cases was compared with that in the Japanese population reported by Sasaki. This comparison revealed that in both sexes between the 4th and 6th decades, the incidence was significantly higher in the former, whereas no significant difference was noted between the two in the 7th decade. As to the location of aneurysms, only the multiple aneurysms group had a significantly greater number of hypertensives than single aneurysm group. These results agree with previous reports that cerebral aneurysm may occur more frequently in the hypertensives than in the normotensives.

Adult↗