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R Kwak

Publications and source records attributed to R Kwak.

At least 19 recordsLinked to original sources
PubMed1988

[Intracranial physiological calcification on computed tomography (Part 1): Calcification of the pineal region].

Of intracranial physiological calcification, common calcification of pineal region, choroid plexus of lateral ventricles and of basal ganglia was examined based on the frequency of occurrence of age and sex and type of CT scanners. Consecutive cases of 2877 (1450 males and 1427 females) underwent plain CT scanning were studied. Pathological calcification was excluded from this study. Three types of CT scanners (SCN-200, Somatom 2 and TCT-10 A) were used. As a whole, calcification was shown in 67.7% in pineal region, 57.6% in choroid plexus of lateral ventricles and 7.5% in basal ganglia. First, we reported in detail the calcification of pineal region, in which calcification occurred most frequently. Calcification in pineal region had a close relation with age by increasing with aging. The youngest patient was 8 years old. There was a striking increase in number of patients aged from 10 to 39 years. There was a gradual increase in those aged over 40 years. Of patients aged from 70 to 79 years, calcification was found in 81.5%. The incidence was noted no changes in patients aged over 80 years. As for patients aged over 20 years, calcification was observed in 75.1% (82.6% males and 68.0% females). In patients aged from 20 to 79 years, the calcification was significantly higher in male than female. Although there was a different incidence of calcification examined by three types of CT scanners, it was not significant. There was no significant difference between thickness of 8 mm section and 10 mm.

Adolescent↗
PubMed1988

[Intracranial physiological calcification on computed tomography (Part 2): Calcification in the choroid plexus of the lateral ventricles].

In this paper, we describe calcification in the choroid plexus of lateral ventricles with a discussion of the frequency of occurrence in categories of age, sex, and laterality, and its correlation with pineal calcification. The study was conducted on 2877 consecutive cases (1450 males and 1427 females) that had plain CT scanning. Three types of CT scanners (SCN-200, Somatom 2 and TCT-10 A) were used. This series included only calcification of the choroid plexus in the trigone of the lateral ventricles (glomus). Calcification was found in none of the cases aged under 9 years, 5.9% aged from 10 to 14 years and 17.4% aged from 15 to 19 years. The calcification rate strikingly increased with increasing age of the cases. It was 51.5% of cases between 30 and 39 years of age. After that, the increasing rate of calcification gradually decreased, however calcification was found in 74.4% of cases aged over 80 years. The calcification rate was 64.7% in our total series of cases aged over 20 years, 66.5% aged over 30 years and 70.7% aged over 50 years. The calcification rate of male cases was greater than that of females in the age group of over 15 years. However, there was a significant difference only in the cases ranging from 60 to 79 years of age. The initial incidence of male cases was found at the age of 12 years and that of females at the age of 16 years. There was no difference in calcification on right and left sides.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

[Aplasia of the posterior arch of the atlas--report on two cases].

Two cases of aplasia of the posterior arch of the atlas incidentally found are reported. Case 1: A 37-year-old man hit the forehead and the right mandible against the front glass at a head-on collision of his car and was brought to the emergency room. He was alert and neurologically normal except for multiple incision wounds with glass fragments in the face. CT, and cervical X-rays revealed total absence of the posterior arch of the atlas. Case 2: A 73-year-old woman, who sustained whip lash injury at an automobile accident, was admitted several hours after injury, complaining of neck and occipital pain. No neurological deficit was seen. CT demonstrated hemi-aplasia of the posterior arch of the atlas and isolated rudimentary posterior tubercle. Review of the literature and discussions were made on the incidence and genesis of this anomaly.

Adult↗
PubMed1987

[Effect of septal lesions on the hippocampal EEG and behavior during DRL learning in the rabbit].

We had reported that hippocampal high frequent activity at 8-10 Hz (alpha-burst) appeared during approach and lever press with the progress of DRL learning. In this study, effect of bilateral septal lesions on hippocampal EEG (especially on alpha-burst) and behavior during 10 second DRL learning was investigated in thirteen rabbits. Using the atlas of Sawyer et al., bipolar electrodes were implanted chronically in bilateral septum at coordinates of A 1-2, L 1 and D 10-11 and dorsal hippocampus at P 3-5, L 4-6 and D 7-8. Septal lesion was made by using 8-mA DC currents for 15-50-sec period enough to abolish hippocampal theta activity. DRL learning was performed after septal lesions in five rabbits. In this group, acquisition of learning was disturbed and rhythmic slow activity of the hippocampus was markedly reduced. However, movement itself was not disturbed. Although hippocampal activity recovered gradually with the progress of session, alpha-burst was not observed by the 70th session. In eight rabbits, septal lesions were made after completion of DRL learning which required 40-50 sessions. In this group, the preservation of DRL learning was disturbed and relearning was not completed by the 30th session after septal lesions. Hippocampal rhythmic activity was remarkably reduced and alpha-burst was disappeared. But, voluntary movement itself was not altered. There are several theories concerning with hippocampal rhythmic slow activity. Some author emphasized that hippocampal rhythmic activity appeared at the time of voluntary movement and it had close relation to voluntary movement.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Anterior osteophytectomy for cervical spondylotic myelopathy in developmentally narrow canal.

The authors present 19 cases of cervical spondylotic myelopathy in patients with developmentally narrow canal treated by microsurgical anterior osteophytectomy with interbody fusion, with follow-up periods of 1 to 8 years (mean 38 months). Postoperatively, the lower limb function, evaluated by Nurick's six-grade classification, improved two or three grades in 16 cases, one grade in two cases, and remained unchanged in one case. The upper limb function, evaluated by the authors' own four-grade classification, improved two or three grades in 11 cases, one grade in seven cases, and remained unchanged in one case. No deterioration caused by the osteophytectomy was seen. During the follow-up period, spondylolisthesis appeared 31 months postoperatively in one patient and soft disc hernia occurred 66 months postoperatively in another; these two patients were treated by a second operation and cervical traction, respectively. The authors conclude that anterior osteophytectomy with interbody fusion is applicable as a surgical treatment of cervical spondylotic myelopathy even where developmental canal stenosis is present.

Adult↗
PubMed1985

[Risk factors of cerebral aneurysm re-rupture during angiography].

Although re-rupture of cerebral aneurysm during angiography has been reported occasionally, we have encountered 13 such patients during eight years since 1974, the incidence corresponding to 4.4 percent of 295 consecutive aneurysm patients on whom a total of 467 angiographies were performed. Extravasation on angiogram was noticed in 10 of these patients. We carefully analyzed the following factors to determine which one is significantly related to aneurysm re-rupture during cerebral angiography. The factors we investigated were sex, age, sites of ruptured aneurysm, surgical risk grade and time interval between the latest rupture of aneurysm and angiography. Our procedures of angiography were standardized as such that contrast material was injected by means of power injector and the injection pressure was adjusted at 2.5 kg/cm2 in vertebral angiography, 3 kg/cm2 in carotid angiography and 4 kg/cm2 in retrograde brachial angiography. Volume of contrast material was 6-8 ml, 10-12 ml and 30-32 ml, respectively. An incidence of re-rupture during angiography when performed within the initial 24 hours after the latest bleeding episode was 12 out of 123 angiographies (9.8%), whereas 1 out of 344 angiographies (0.3%) which were performed later than 24 hours. This difference was significant (p less than 0.001). These data were further analyzed every one hour period. It was learned that re-rupture rate was significantly high, 9 out of 45 patients (20.0%) when angiography was done within 5 hours after the latest aneurysm rupture (p less than 0.01), particularly, 8 out of 27 patients (29.6%) within 3 hours (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Trigeminal neurinoma presenting abducens nerve palsy as initial symptom: a report of two cases].

Two cases of trigeminal neurinoma presenting abducens nerve palsy as initial symptom are reported. Case 1. A 33-year-old female was admitted because of double vision of two months duration. Neurological examination revealed left abducens nerve palsy. CT scan disclosed a left parasellar tumor with a homogeneous enhancement effect. The tumor was subtotally resected by left extradural subtemporal approach, and diagnosed as trigeminal neurinoma. Case 2. A 18-year-old female was admitted because of double vision of one month duration. Neurological examination revealed left mydriasis and left abducens nerve palsy. CT scan disclosed a low density mass in the left cerebellopontine angle region and enhanced parasellar mass. The cystic mass located at the posterior fossa was removed by left retromastoid suboccipital approach, and diagnosed as trigeminal neurinoma. In these two cases, the abducens nerve palsy disappeared within two months postoperatively. The trigeminal neurinoma presenting abducens nerve palsy as initial symptoms is rare. We were able to collect six similar cases from the literature. All of them, including present two cases, were classified as ganglion type. It was suspected that the abducens nerve was compressed by the trigeminal neurinoma at the cavernous sinus, the petrous apex or the posterior fossa.

Abducens Nerve↗
PubMed1985

[A case report of intracerebral tuberculoma during antituberculous therapy].

A case of multiple intracerebral tuberculoma occurred in the course of anti-tuberculous therapy is reported. A 16-year-old high school boy had been treated with isoniagid, streptomycin and paramino-salicylic acid on the tuberculous pleulitis for 3 months previously. He was admitted to our hospital because of progressive headache associated with vomiting. Neurological examination revealed bilateral full papilledema and incomplete bilateral abducens palsy. An immediate CT study with contrast enhancement demonstrated two small ring-like mass with considerable perifocal edema in the left temporal and occipital lobe, respectively. Intracerebral tuberculoma was considered to be most likely, so the patient was given antituberculous therapy with steroid and mannitol. However, despite of medical decompression, he developed intracranial hypertension aggravated, leading to removal of tumor 7 days after admission. Initially left temporal tuberculoma, which had more extensive and prominent perifocal edema, was successfully excised. The specimen was a walnut-sized granuloma with hard capsule including pus inside. Numerous tuberculous bacilli were identified with Ziel-Nielsen staining technique from the pus. Postoperative course was gratifying, and other tumor in the left occipital lobe, which was also diagnosed as tuberculoma, was treated with continuing administration of isoniagid, ethanbutol and rifampicin. However, the former two drugs were forced to be discontinued because of agranulocytosis. Only rifampicin was maintained for 2 months thereafter but no decrease of the size was observed in serial CT studies. Then left occipital tuberculoma was removed. The pathology was tuberculoma with positive bacilli staining. He discharged 1 month later without any neurological deficit but was on antituberculous therapy (rifampisin) as an outpatient for 3 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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↗
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↗