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Biomedical subjects

K Takakura

Publications and source records attributed to K Takakura.

At least 415 records · Page 23Linked to original sources
PubMed1984

[Dynamic computed tomography of brain tumor].

Dynamic computed tomography (CT) has been widely used because of its simplicity, but regional cerebral perfusion of brain tumors has not critically been evaluated. This study was conducted to evaluated parameters obtained from the dynamic perfusion study in brain tumors and to clarify the usefulness of the dynamic CT comparing with Xe-enhanced CT. Dynamic CT was performed on 20 patients with brain tumor (three meningiomas, one pineal tumor, three metastatic brain tumors, thirteen gliomas). Dynamic CT consisted of performing six rapid sequential scans after a bolus intravenous injection of 40 ml of iodinated contrast medium. In this study, five parameters (corrected first moment, area, peak, time to peak, percent terminal height) were obtained from computer analysed curve fit on time density curve profile of serial scanning. In Xe-enhanced CT, serial CT was taken every three or five minutes during inhalation of 40 to 50 percent stable xenon. Flow rate constant (K), partition coefficient (lambda) and cerebral blood flow (CBF) for each pixel were calculated from delta HU (Hounsfield unit) and end-tidal air curve and displayed on CRT as images. In patients with meningioma, values of area and percent terminal height of the tumor were much higher than those of contralateral gray matter, and these findings show excessive increase of the intratumoral blood volume and extreme extravasation of iodinated contrast medium respectively. In patients with metastatic brain tumor or malignant glioma, which were enhanced by contrast medium, the values of all parameters of the tumors were higher than contralateral gray matter. Increase of intratumoral blood volume and destruction of blood brain barrier are suggested in these tumors. In the remaining patients with glioma, which was not enhanced, the values of corrected first moment and time to peak of the tumors were higher but area and peak were lower than contralateral gray matter. These findings show decrease of intratumoral blood volume and delay of mean transit time and arrival time of the bolus. Compared with CBF measured by Xe-enhanced CT, it was suggested that high density area of metastatic brain tumor or malignant glioma consisted of viable tumor cells, and in patients with glioma, low density area adjacent to the tumor with contrast enhancement was the invasive site of the tumor. Using dynamic CT, we were also able to distinguish the tissue contains viable tumor cells from the other part of brain by the differences in the parameter value.

Adult↗
PubMed1984

[Neonatal survival and perinatal factors in infants born at 24 to 32 weeks of gestation].

Clinical associations between neonatal survival and perinatal factors were studied in very premature infants delivered at Kurashiki Central Hospital Perinatal Center during April 1979 to March 1983. The very premature singleton infants without congenital anomaly were studied in the present work, including 45 live-birth infants born at 24 to 32 weeks of gestation and weighing 590 to 2,000g at birth. The mortality rate for male infants was higher than that for female infants, but this difference was not statistically significant. The mortality rate for infants born at 28 to 32 weeks of gestation was 2.9%, and that for infants weighing 1,000g or more at birth, respectively. The cause of all these neonatal death was massive aspiration syndrome with intracranial hemorrhage, and severe neonatal asphyxia. The mortality rate for infants born at 24 to 32 weeks of gestation was 60%, and that of infants weighing 999g or less, 60%, respectively. The cause of all these neonatal deaths was respiratory distress syndrome with intracranial hemorrhage. Clinically, it was suggested that cesarean section after onset of labor, PROM, and Betamethasone prior to delivery increased the survival rate of these infants statistically significantly. The most important neonatal complication in the prognosis of very premature infants was intracranial hemorrhage. The most correlated perinatal factors of neonatal intracranial hemorrhage were one min. Apgar score and fetal lung maturation.

Apgar Score↗
PubMed1984

[Synchronization chemoradiotherapy for malignant gliomas].

Cellular synchronization chemoradiotherapy was performed in 122 patients with glioblastoma and malignant astrocytoma (GrIII) registered between April 1977 and August 1982. The study was a non-randomized clinical phase II trial. The chemotherapeutic agents employed as synchronizers during the irradiation were VM26 (epipodophyllotoxin) and vincristine (VCR) as plant alkaloids and ACNU as a nitrosourea. Either VM26 or VCR was administered on D1, D2 and D3 at the dosage of 1 mg/kg (0.025 mg/kg-VCR) body weight. ACNU was administered on D2 and D3 at the dosage of 1 mg/kg body weight. The duration of the chemotherapy was eight to fourteen days at the initial induction stage and almost eight weeks at the maintenance stage. Thus, two synchronization arms of VM26 + ACNU and VCR + ACNU were employed. The regimen-VM 26 + ACNU + Radiation (Rad) could yield the initial induction of CR + PR-30%, NC-50%, and PG-15% in 58 cases. Long-term survival, calculated by the cumulative survival rate, was as follows: one year, 58%; two years, 42%; three years, 32%; four years, 30%, and five years, 25%. The regimen VCR + ACNU + Rad could yield the initial induction of CR + PR-28%, NC-49%, and PG-23% in 64 cases. The cumulative survival rate was calculated as follows: one year, 55%; two years, 42%; three years, 27%; four years, 22%, and five years, 22%. As a control, particularly for the survival rate, the data of the All-Japan Registry were revised to correspond to our study population. The survival rate of simple radiation cases thus revised was as follows: one year, 43%; two years, 23%; three years, 11%; four years, 7%, and five years, 5%. The comparison between VM 26 plus ACNU and VCR plus ACNU yielded a higher initial induction response of 35% for the former (vs. 28% for the latter), although it is difficult to make a judgement on the excellence of the regimen involving VM 26 plus ACNU, because this trial was clinical phase II. On the other hand, compared with the data from the All-Japan Registry, each regimen of cellular synchronization radiation therapy could achieve statistically more excellent responses both in the initial induction and the long-term survival (p less than 0.01). Thus, cellular synchronization radiation therapy is a hopeful therapeutic method for malignant glioma, with less side effects and statistically confirmed higher responses.(ABSTRACT TRUNCATED AT 400 WORDS)

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1983

Localization of concanavalin A binding sites in human pituitary adenoma cells as revealed by HRP-labelling method.

Intracellular lectin (Con A)-binding sites of human pituitary adenoma were examined by electron microscopy using the horseradish-peroxidase (HRP)-labelling technique. In this study were used 16 cases of human pituitary adenomas operated on in our clinics between 1977 and 1981: they concluded 4 each of PRL-, GH-, ACTH-producing and hormonal non-functioning adenomas. In parallel with the detection of lectin-binding sites, basal levels of their secreting hormones were determined by the radioimmunoassay technique, and their producing hormones were characterized light microscopically by the immunocytochemical HRP-labelling technique. In the present study, for hormonal functioning adenoma cells, mature or large granules of each specific type of adenoma cells had no definite Con A-binding sites. On the other hand, immature or small secretory granules of RPL- or GH-producing adenoma cells showed a positive reaction with Con A. ACTH-producing adenomas so far examined revealed no definite binding sites. Some variable results were obtained concerning non-functioning adenomas. Lectins have been and will be very useful in the detection of different subtypes of adenomas in each specific group.

Adenoma↗
PubMed1983

Extracranial-intracranial bypass to the proximal posterior cerebral artery and to the proximal middle cerebral artery for multiple occlusive cerebrovascular disease.

A 48-year-old man with a multiple occlusive cerebrovascular disease involving both the carotid and the vertebrobasilar systems is reported. Faced with noneffective conservative treatment, a surgical approach was carried out. As the patient had poorly developed posterior communicating arteries, two extracranial-intracranial bypasses were performed for both the carotid and the vertebrobasilar circulations; extracranial-intracranial bypasses with interposed saphenous vein grafts between the left external carotid artery and the proximal segment of the left middle cerebral artery, and between the right external carotid artery and the proximal segment of the right posterior cerebral artery. Advantages, precautions, and techniques of this kind of bypass procedure are discussed.

Brain Ischemia↗
PubMed1983

A double-blind clinical evaluation of the effect of Nizofenone (Y-9179) on delayed ischemic neurological deficits following aneurysmal rupture.

The effect of Nizofenone (Y-9179), a vertebral protective agent, on delayed ischemic neurological deficits following subarachnoid hemorrhage (SAH) due to aneurysmal rupture was investigated by a cooperative double-blind clinical trials. Delayed ischemic neurological deficits following SAH are closely associated with the occurrence of vasospasm, and the effectiveness of any cerebral protective agent depends on sufficient coverage by the drug over the period around the onset of ischemic insult. Therefore, the study was designed so that the effect of Nizofenone could be analyzed in terms of these two factors. In patients admitted within day 9 of SAH, drug administration was immediately initiated and continued for 5 days. When delayed ischemic neurological deficits occurred, angiography was carried out to confirm the presence of vasospasm, and then drug administration was extended for an additional 5 days. Ten of the 100 cases enlisted in the study were excluded prior to code-breaking because of the occurrence of severe complications not related to vasospasm. Out of the 42 cases of the Nizofenone group and 48 of the placebo group, 25 and 29 developed vasospasm, respectively. Thus Nizofenone did not prevent vasospasm. Of the 25 cases of the Nizofenone group with vasospasm, 13 cases received sufficient drug coverage around the onset of vasospasm. The placebo group, the total Nizofenone group, and the Nizofenone group with sufficient drug coverage were stratified according to the occurrence of vasospasm. The disability status index one month after admission and the neurological functions, such as motor and speech functions, of each group were then compared. In patients who developed vasospasm, only the Nizofenone group with sufficient drug coverage had a significantly better outcome than the placebo group (p less than 0.05). No particular side effect of Nizofenone was observed. Thus, the results indicate that Nizofenone may be useful in the therapy of delayed ischemic neurological deficits following SAH, although the effect of the drug may be considerably influenced by the timing of its administration.

Adult↗
PubMed1983

[Adjuvant immunotherapy with levamisole for malignant glioma].

The long-term therapeutic results in patients with glioblastoma multiforme and malignant astrocytoma were compared between 15 cases of levamisole treated group and 18 cases of control group similar in method and time of treatment to the levamisole treated group. As the result, it was found that the prolongation of life was noted in the levamisole treated group compared with the control. In adult patients, the levamisole treated group survived significantly longer than the control group (p less than 0.05). There is, however, no significant difference of prolongation of the survival time between the levamisole treated (8 cases) and control (8 cases) groups, both which were pretreated by chemoradiotherapy using ACNU and vincristine. This paper refers also to side effects of levamisole.

Adolescent↗
PubMed1983

[Glioblastoma and fibrosarcoma in the brain with metaplastic bone formation--a case report].

The authors report a case in which left deep temporal fibrosarcoma with calcified area developed about 6 months after radiation therapy for left temporal astrocytoma. A 37 year-old woman was admitted to our clinic because of headache and visual deterioration. CT scan and angiography suggested left deep temporal glioma and on August 5, 1980, partial resection was performed. Histological sections showed astrocytoma G 2. Postoperative course was uneventful and she left the hospital after radiation therapy of 50 Gy. On March, 1981, right hemiparesis was noticed and progressed rapidly. CT scan suggested left temporal tumor recurred. On March 30, 1981, second operation was performed and this time, histological sections showed glioblastoma. After operation, beta-Interferon (IFN) was given intratumorally via Ommaya's reservoir (3 X 10(6) IU, daily). But in spite of IFN therapy, tumor became larger and she died on June 30, 1981. Autopsy revealed coexistence of glioblastoma and fibrosarcoma with metaplastic bone formation. A brief discussion concerning the problem of cerebral mixed tumors follows the description of the case.

Adult↗
PubMed1983

[Second-look operations and chemotherapy for malignant tumors of the brain].

Second-look operations for glioblastomas, one of the most malignant types of brain tumor, were performed after the administration of chemotherapeutic treatments of general-VM 26 plus ACNU, local-MTX, or interferon-beta in each of ten, two, and three cases, respectively. Patients who had received the treatments were divided into two groups, living and deceased, as of August 1982. Therapeutic evaluation was performed with clinical parameters. Among the cases of CR, one (a 14-year-old female) had undergone surgery four times in the four years following onset, and no trace of tumor shadow appeared on the CT grams that were taken one month after the last surgery. Her performance was evaluated as almost 100% (ECOG). In cases of local administration, one case, which had been treated with IFN-beta, demonstrated an apparent decrease in the growth fraction and a pronounced decrease in tumor progression potency. Cell kinetic analyses were also performed, and cell cycle time and growth fraction were estimated by computer with the aid of flow cytometry. Efficacious chemotherapy yielded a decreased value of the growth fraction and an increase in cell cycle time. The decreased value of the growth fraction demonstrates especially well the effectiveness of a chemotherapeutic regimen. The cell kinetic analyses aided in the rational establishment of a chemotherapeutic regimen. Second-look operations for malignant brain tumors will enable more effective refinements in chemotherapeutic regimens and more successful results.

Adolescent↗
PubMed1983

[Case of tinnitus, vertigo, and a loss of caloric response due to neurovascular compression].

The authors report a case of neurovascular compression of the eighth cranial nerve in a 49-year-old businessman. The patient was admitted to the University of Tokyo Hospital because of progressive vertigo and tinnitus on the right without hearing loss over the seven years prior. There were no other symptoms. The general examination was normal. He was neurologically intact except for loss of caloric response. Audiometric studies and brain stem response were normal. The findings of routine hematology, biochemistry, and serology were within normal limits. Tomogram showed that right internal auditory meatus was wider than the left by 2 mm. Computed tomography with metrizamide demonstrated a filling defect in the right cerebellopontine angle. We decided to proceed with exploratory operation with the tentative diagnosis of a left cerebello-pontine angle mass, perhaps neurinoma en plaque meningioma, or epidermoid tumor. Left retromastoid craniectomy with microsurgical exploration of the cerebellopontine angle revealed not a tumor, but a loop of the anterior interior cerebellar artery (AICA) compressing the eighth cranial nerve close to the porus acousticus. A piece of muscle was inserted between the eighth cranial nerve and the AICA. His postoperative course was uneventfull with complete relief of symptoms and without impairment of hearing. In patients with hemifacial spasm and trigeminal neuralgia, neurovascular compression (NVC) has been found at the root entry zone of the facial or trigeminal nerves close to the brain stem at the "junction zone" on the glia and schwann sheath of these nerves.(ABSTRACT TRUNCATED AT 250 WORDS)

Caloric Tests↗
PubMed1983

[Visualization of cerebellopontine angle diseases by nuclear magnetic resonance imaging].

The preliminary results from the clinical use a prototype whole body nuclear magnetic resonance (NMR) machine constructed by Toshiba Inc. are presented. Cranial NMR scans were performed on more than 30 cases with broad spectrum of neurologic diseases using saturation-recovery and inversion-recovery sequences with a field strength of 1500 Gauss. Selective excitation sequence was used for the slice selection and filtered backprojection was used to reconstruct the images. They were displayed on a 256 X 256 matrix as 12 mm thick sections. Data acquisition time varied between 3 and 12 minutes. Our initial experiences with six cases harboring cerebellopontine angle lesions disclosed advantages and disadvantages of NMR imaging in comparison with X-ray CT. The advantages were the absence of linear artifacts from the surrounding bone, the marked gray-white matter differentiation, and the variety of tomographic planes available. The disadvantages included the lack of bone detail, the lack of visualization of the major intracranial vessels, and the long time required for scanning (several minutes per slice). Although much continued evaluation is necessary, NMR seems to have vast potential as a diagnostic tool.

Adult↗
PubMed1983

[Tomographic analysis of CBF in cerebral infarction].

Cerebral perfusion was examined in various types of occlusive disease by computed tomographic CBF method. The method utilized has several advantages over conventional studies using isotope, providing high resolution images in a direct relation to CT anatomy. Ten representative cases were presented from 25 consecutive cases of occlusive disease studied by this method. The method included inhalation of 40 to 60% xenon with serial CT scanning for 25 min. K (build-up rate), lambda (partition coefficient) and CBF values were calculated from HU for each pixel and Xe in expired air, based on Fick's principle, and displayed on CRT as K-, lambda- and CBF-map separately. CBF for gray matter of normal control was 82 +/- 11 ml/100 gm/min and that for white matter was 24 +/- 5 ml/100 gm/min. The ischemic threshold for gray matter appeared to be approximately 20 ml/100 gm/min, as blood flow in focus of complete infarction was below this level. Blood flow between 20-30 ml/100 gm/min caused some change on CT, such as localized atrophy, cortical thinning, loss of distinction between gray and white matter and decreased or increased density, which were considered to be compatible with pathological changes of laminar necrosis or gliosis with neuronal loss. In a case with occlusion of middle cerebral artery with subsequent recanalization, causing hemorrhagic infarct, hyperemia was observed in the infarcted cortex that was enhanced by iodine. Periventricular lucency observed in two cases, where blood flow was decreased below threshold, could be classified as "watershed infarction" mainly involving white matter. In moyamoya disease, blood flow in the anterior circulation was decreased near ischemic level, whereas that in basal ganglia and territory of posterior cerebral artery was fairly preserved, which was compatible with general angiographic finding of this disease.

Adult↗
PubMed1983

[Some practical problems of clinical diagnosis of brain death].

The authors experienced thirty brain deaths including eighteen head injuries and seven cerebrovascular accidents during the period from Nov. 1980 to Dec. 1982 and encountered with some practical problems on clinical diagnosis of brain death. In sixteen patients subjected to barbiturate (pentobarbital) therapy, the attempt to meet the criteria of brain death made it necessary to confirm the total cerebrocirculatory arrest as well as to measure the serum concentration of pentobarbital and assure its level low enough. But as a result of the angiograms performed in twenty-four cases the cerebral angiography sometimes failed to give sufficient evidence to confirm it not merely because of the angiographical intracranial delayed opacification but also because of the dissociation of filling between supra- and infratentorial spaces or between right and left hemispheres. And besides the contrast enhancement of cerebral vessels was verified in computed tomograms of two cases among ten cases who had already met the criteria and demonstrated angiographical nonfilling phenomenon. The angiographical narrowing of C 1-2, A 1, M 1 portions or basilar artery observed on serial angiograms preceding the angiographical nonfilling phenomenon was regarded as direct vascular compression by cerebral swelling or vasospasm and considered to suggest that brain death might be impending. At present the continuous monitoring of intracranial pressure performed in twenty-six cases proved to be a convincing guide to suspicion of brain death or impending brain death according to decrease in cerebral perfusion pressure and appearance of so-called plateau waves recorded in four cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

[Extra-intracranial bypass and internal carotid artery ligation in one-stage operation for intracavernous and giant carotid aneurysm].

The combined one-stage operations, STA-MCA anastomosis and internal carotid artery (ICA) ligation (or trapping) were carried out in 11 cases (Age): 18-79 yrs, Av.: 45.8 yrs) of ICA aneurysms which were inaccessible for a direct operation because of their locations and sizes. First the STA-MCA anastomosis was performed under general anesthesia. Then the patient was awaken and thereafter under local anesthesia the ICA was temporarily clamped for 30 min. under induced hypotension to check whether any ischemic signs appeared. This was followed by proximal ICA ligation when no ischemic signs were observed. In all 11 cases, the anastomosis was patent. The aneurysms disappeared. Neither cerebral ischemia nor rebleeding from the aneurysms was seen during the long follow-up. The mean value of the bypass flow was 119 m/min which was twice as much as that in the cases of other occlusive cerebrovascular diseases and which was about one third of the blood flow of the ICA. Cerebral blood flow measurements through 133Xe inhalation method revealed that there was no difference in rCBF values between the operated and non-operated sides and that their values were within normal limits. The postoperative blood pressure was unchanged in 42% of our 11 cases, temporarily elevated and thereafter normalized in 33% and persistently elevated in 25%. Ophthalmodynamometry showed that the pressure of the central retinal artery decreased postoperatively in a degree of 5-10% in comparison to the non-operated side. No visual impairment was observed postoperatively (except case 3, see the text). These combined operations, STA-MCA anastomosis and ICA ligation were beneficial in preventing the potential postoperative cerebral ischemia. Intra-arterial pressure measurements of the STA and MCA suggested that the one-stage operations of these two procedures are better than the two-stage operations for the patency of the anastomosis because the pressure gradient between the donor and recipient vessels is increased (from 10.3 mmHg to 49.3 mmHg) by this technique. Temporary ICA clamp for 30 min. under induced hypotension in local anesthesia is useful to check whether the one-stage operations can be tolerated or not. EC/IC bypass with an interposed saphenous vein graft is a more beneficial surgical technique than a routine STA-MCA anastomosis, because an immediate and larger amount of bypass flow can be obtained.

Adult↗