Search PubMed⌕ Search

Biomedical subjects

R Kwak

Publications and source records attributed to R Kwak.

At least 55 records · Page 3Linked to original sources
PubMed1979

Angiographic study of cerebral vasospasm following rupture of intracranial aneurysms: Part I. Time of the appearance.

An investigation of the time of appearance of vasospasm as seen angiographically after the onset of subarachnoid hemorrhage was carried out on 797 cases of intracranial saccular aneurysm in which operations were performed. It has been reported that vasospasm often occurs early after the onset of subarachnoid hemorrhage. With only one subarachnoid hemorrhage, vasospasm occurred within three days after the hemorrhage in only 4.2% of the 120 cases in this study. The appearance of vasospasm was most frequently seen angiographically between ten and 17 days. During this period vasospasm was seen in 49.1% of 116 cases. In those cases with a subarachnoid hemorrhage one to 17 days before the last one, vasospasm within three days after the last hemorrhage was seen in 38.7% of 62 cases. During the period between ten and 17 days after the last hemorrhage, vasospasm was seen in only 20% of 25 cases. The preceding subarachnoid hemorrhage, which had occurred between one and 17 days before the last hemorrhage, seemed to be responsible for the high rate of vasospasm within three days after the last hemorrhage, and the low rate of vasospasm in the period between ten and 17 days after the last hemorrhage.

Brain↗
PubMed1979

Angiography study of cerebral vasospasm following the rupture of intracranial aneurysms: Part II. Relation between the site of aneurysm and the occurrence of the vasospasm.

The relation between the occurrence of vasospasm and the site of ruptured aneurysm was investigated. Vasospasm tended to occur initially on arteries close to the aneurysm, later extending to other locations. Contralateral spasm was more frequent the closer the site of the aneurysm to the mid-sagittal line. The spasm observed angiographically varies in relation to the site of the aneurysm; the site of the hematoma in the subarachnoid space was supposed to be the cause of such variation.

Brain↗
PubMed1979

[Two cases of azygos anterior cerebral artery aneurysm (author's transl)].

Two cases with azygos anterior cerebral artery were reported from an analysis of 37 cases of distal anterior cerebral artery aneurysm. Case 1 was a 57-year-old woman. She had an attack of subarachnoid hemorrhage two months before admission to our clinic. The anterior cerebral artery was not demonstrated on the right carotid angiogram, and an azygos anterior cerebral artery was visualized on the left carotid angiogram. The aneurysm was situated at the distal end of the azygos artery. Case 2 was a 71-year-old hypertensive woman. Subarachnoid hemorrhage occurred 6 days before admission to our clinic. The left carotid angiography with contraleteral compression revealed an azygos artery and an aneurysm in its middle part. The azygos arteries in both cases were confirmed at operation and aneurysmal necks were managed without any serious deficit. The distal anterior cerebral artery aneurysm is frequently accompanied by azygos artery. This vascular anomaly may cause a hemodynamic change and may be one of the factors of aneurysmal formation at this part.

Aged↗
PubMed1978

Ipsilateral cerebral atrophy with thalamic tumor of childhood. Case report.

A case of cerebral tumor with ipsilateral cerebral hemiatrophy is presented and five previously reported cases are reviewed. The etiology of this entity is discussed on the basis of the symptomatological and clinicopathological findings noted in these six cases. It is suggested that ipsilateral cerebral hemiatrophy is due to thinning of the cerebral cortex with degeneration and disappearance of ganglion cells, demyelination in the subcortex, and destruction of axons. The mechanism proposed for ipsilateral cerebral hemiatrophy due to thalamic tumor is that thalamic tumor causes degeneration and disappearance of thalamic ganglion cells and nerve fibers, with consequent secondary Wallerian degeneration of afferent and projecting fibers from the thalamus as well as retrograde degeneration of efferent fibers, thus resulting in extensive atrophy of the cerebral cortex and subcortical tissue.

Adolescent↗
PubMed1978

[Arrest reaction in man: motor arrest response by electrical stimulation of the deep structure of the cerebrum (author's transl)].

In spite of many reports of arrest reaction in animals, there are very few reports in man. During a therapeutic stereotaxic operation we observed peculiar phenomena caused by electrical stimulation to the deep structure of the cerebrum. This phenomenon is quite similar to that reported by Van Buren, but there are a few differences between them. Arrest reaction was observed in 14 of 23 cases, 17 of 28 tracks. Stimuli which caused the arrest reaction were 60--100 Hz square waves of, 1 msec duration and 5--15 V. The electrical stimulation caused an interruption of counting and other motor actions, which could be resumed following release of stimuli. Psychic confusion or memory disturbances were not observed with the exception of a few cases. 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↗
PubMed1978

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. This phenomenon is quite similar to that reported by Van Buren, but there are a few differences between them. Arrest reaction was observed in 14 of 23 cases, 17 of 28 tracks. Stimuli which caused the arrest reaction were 60--100 Hz square waves of 1 msec duration and 5--15 V. The electrical stimulation caused an interruption of counting and other motor actions, which could be resumed following release of stimuli. Psychic confusion or memory disturbances were not observed with the exception of a few cases. 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 vicinity of the caudate nucleus. However, the possibility that the current spread to the motor fiber cannot be definitely ruled out.

Adult↗
PubMed1978

[Effects of bilateral amygdalectomy on levers 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 amygdalectomy were examined with the Skinner box. There was no changes in general behaviour and no impediment of CRF learning. But the completion of DRL learning was delayed by amygdalectomy. In the stage of completion of DRL learning there was no difference of total number of the reinforcement and the lever pressing between the control group and amygdalectmized group. But there was the impediment of DRL learning by the analysis of frequency distribution of inter-response time and of transition probability matrix in the amygdalectimized group. We thought that this impediment of DRL learning was due to the impediment of selection of decision of lever pressing action. The memory of the preamygdalectomy was maintained well after amygdalectomy.

Amygdala↗
PubMed1978

[Angiographical study of ruptured aneurysm in the multiple aneurysm patients (author's transl)].

Sixty four multiple intracranial aneurysm cases have been analysed for the purpose of identifying the relation between aneurysm rupture and aneurysmal features, mass signs, vasospasms and locations of the aneurysms. 1) 85% of the larger and largest aneurysm in each case were the ruptured aneurysm. 2) Aneurysms with a greater ratio of length to width showed a high frequency of rupturing. 3) Irregularities of the aneurysmal wall and the existence of a daughter aneurysm attached to the main aneurysm have a tendency to rupture. 4) Evidence of mass signs, associated with intracerebral, subarachnoid and subdural hematoma or a cerebral edema is also useful for the identification of the ruptured aneurysm. 5) Anterior communicating artery aneurysms have a relatively high frequency of being the ruptured aneurysm in cases of multiple aneurysm. 6) By utilizing all the investigated factors of the angiogram, the ruptured aneurysm might be identified in about 90% of the cases of multiple aneurysms.

Adult↗
PubMed1978

[Hemodynamics in the anterior part of the circle of Willis in patients with the anterior communicating artery aneurysm--a study by cerebral angiography (author's transl)].

In order to study the cerebral angiographic findings of the hypoplasia of the A1 of the anterior cerebral artery, and the abnormal blood circulation in the anterior part of the circle of Willis, 485 patients who had had at least bilateral carotid angiography and complete data were selected, out of 1,000 patients with cerebral aneurysms to whom intracranial direct surgery had been done from June 1961 to September 1975. Patients with multiple cerebral aneurysms were excluded in this study. Seventy six patients were selected as controls. 1. Cerebral angiography revealed that hypoplasia of the A1 of the anterior cerebral artery is much more frequent in patients with aneurysms of the anterior communicating artery than in those with aneurysms of other intracranial arteries. It was observed in 145 of the 213 patients with aneurysms of the anterior communicating artery (68.1%). As for the hypoplasia of the A1, the angiographic findings corresponded to the surgical findings in 86.9% of all the patients. The incidence of hypoplasia of the left and right A1 portions was higher in patients with aneurysms of the anterior communicating artery than in those with aneurysms of other intracranial arteries. The incidence was about 3 times higher on the right side than on the left side. 2. It was considered that the abnormal blood circulation was observed in the anterior part of the circle of Willis in 155 patients, including 145 with angiographic findings of hypoplasia of a unilateral A1 and 10 with anomalies of the anterior communicating artery or A1 of anterior cerebral artery other than hypoplasia, out of 213 patients with aneurysms of the anterior communicating artery (72.8%). 3. The above findings are considered important for a diagnosis of an aneurysm of the anterior communicating artery and for a surgical approach.

Adolescent↗
PubMed1978

[The angiographical study on cerebral vasospasm following the rupture of intracranial aneurysm (1st report).--Time relationship between vasospasm on angiography and the onset of subarachnoid hemorrhage (aurhor's transl)].

Time relationship between the presence of vasospasm on angiography and the onset of subarachnoid hemorrhage (SAH) was investigated with 797 direct surgical cases with intracranial saccular aneurysm. It has been said that vasospasm would occur in early days after the onset of SAH. But in this paper, in the cases with only one history of SAH, vasospasm occurred within 3 days after SAH was seen in only 4.2% of the 120 cases. The peak of vasospasm on angiography was seen in the period between 10 and 17 days after SAH. During this period vasospasm was seen in 49.1% of the 116 cases. Meanwhile, in the cases with preceding SAH occurred between 1 and 17 days before the onset of the last SAH, vasopasm occurred within 3 days after the last SAH was seen in 38.7% of the 62 cases. On the contrary, during the period between 10 and 17 days after the last SAH, vasospasm was seen in only 20% of the 25 cases. Preceding SAH occurred between 1 and 17 days before the last SAH seemed to be responsible for the high rate of vasospasm within 3 days after the last SAH and the low rate of vasospasm in the period between 10 and 17 days after the last SAH.

Adult↗
PubMed1978

[Anterior communicating artery aneurysms accompanied with anomalies or anterior communicating artery (author's transl) ].

The investigation was carried out on arterial anomalies complicated with 296 cases of single aneurysm of anterior communicating artery and on the etiological significance of the anomalies in the development of cerebral aneurysms. Either the fenestration in anterior communicating artery or the presence of more than 2 anterior communicating arteries was observed in 17 cases (5.7%). As the anomaly was duplicated in some of these cases, the total number of cases with anomalies of anterior communicating artery became to be 26 cases (8.8%) out of 296 cases investigated. This occurrence rate was not higher than those observed in other cerebral aneurysmal cases and the control cases, which were reported previously. There was no significant difference as to the occurrence rate of hypoplasia of the A1 portion between the cases whose aneurysms of anterior communicating artery were complicated with arterial anomalies and the cases without the arterial anomalies.

Circle of Willis↗
PubMed1978

[Relationship between the afferent artery and the site of neck of anterior communicating artery aneurysm, and hemodynamics in the anterior part of the circle of Willis (author's transl)].

Of 346 patients with direct intracranial surgery for an aneurysm of anterior communicating artery that we have experienced from June 1961 to September 1975, 213 patients having sufficient data were selected to study a relationship between hypoplasia of the A1 of the anterior communicating artery, and sites of an afferent artery and a neck of an aneurysm. 1. Ninety seven of 182 patients who had had the bilateral angiography before surgery had hypoplasia of the right A1, 90 of which (92%) had an afferent artery of an aneurysm only in the left A1. All 29 patients with hypoplasia of the left A1 had an afferent artery of an aneurysm only in the right A1. An afferent artery was limited to the dominant A1 in about 95% of them. 2. Angiography revealed that of 204 patients in whom the neck of an aneurysm in the anterior communicating artery was confirmed, 140 patients had hypoplasia of a unilateral A1. The neck of an aneurysm was located at the bifurcation of the dominant A1 and the anterior communicating artery in 48 of the 140 patient (34.3%), at the bifurcation of the non-dominant A1 and the anterior communicating artery in 14 patients (10.0%), and in the anterior communicating artery itself in 78 patients (55.7%). Cerebral angiography revealed that the neck of an aneurysm was more than 3 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. 3. The above findings suggest that hemodynamics in the anterior part of the circle of Willis may participate in the initiation, growth, and rupture of an aneurysm of the anterior communicating artery.

Adult↗