Biomedical subjects

K Takakura

Publications and source records attributed to K Takakura.

At least 181 records · Page 10Linked to original sources

PubMed1994

Ultrasound guided endoscopic neurosurgery--new surgical instrument and technique.

For minimal invasive endoscopic neurosurgery, a mini-caliber endoscope equipped with a useful working channel and its guidance system is basically essential. We developed the device for ultrasound guided endoscopic neurosurgery. A minicaliber fiberscope with an outer diameter of 3.4 mm equipped with 2.5 mm of working channel for forceps, suction, and coagulation probe was developed. A 5 MHz phase arrayed 12 mm ultrasound probe was used as guidance system. A fixation device for the mini-caliber fiberscope and ultrasound probe was also constructed. The surgical procedure is very simple, and can be performed through a 2 cm burr hole. Real-time and a directly visualized image might provide more safety and reliability during brain surgery.

Brain Diseases↗

PubMed1994

Clinico-pathological study of malignant lymphoma of the central nervous system.

This report describes the clinico-pathological features of a group of 36 patients with malignant lymphoma of the central nervous system (CNS) who were treated at one institution between 1970 and 1993. All cases were B cell type lymphomas. The authors summarize the most salient findings with respect to clinical course, pathology, treatment and disease outcome, and emphasize the value of diagnostic and therapeutic modalities in the management of patients with primary CNS lymphoma.

Adolescent↗

PubMed1994

Comparison between the effects of treatment in vitro and in vivo with lipopolysaccharide on responsiveness of rat thoracic aorta.

Effects of treatment in vivo and in vitro with lipopolysaccharide (LPS) on the responsiveness of rat thoracic aorta were examined. The endothelium-denuded aortic strips isolated 6 hr after intraperitoneal (i.p.) administration of LPS (20 mg/kg), which could produce hemodynamic changes, relaxed in response to L-arginine. The same amplitude of relaxation was produced by L-arginine in the aortic strips incubated with a lower dose of LPS (1 microgram/ml) in vitro for 6 hr. Both relaxing responses were inhibited by NG-nitro-L-arginine (L-NOARG). The contractile responses to phenylephrine and KCl were reduced by LPS treatment in vivo or in vitro, but the extent of inhibition was greater in vivo than in vitro. Further, the attenuation of contractile responses was completely reversed by L-NOARG in the strips treated in vitro, whereas the reversal by L-NOARG was incomplete in the strips treated with LPS in vivo. Endothelium-dependent relaxation induced by acetylcholine was attenuated by LPS in vivo but not in vitro. These results suggest that the hyporesponsiveness of rat thoracic aorta after treatment in vitro with LPS, which can produce hemodynamic changes, may be related to an enhanced NO production in the smooth muscle cells, while not only the NO pathway but also additional factors may be involved in the vascular hyporesponsiveness of the sepsis rats.

Acetylcholine↗

PubMed1994

[Treatment of malignant brain tumor].

The pathophysiology and treatment of malignant brain tumors (malignant glioma, metastatic brain tumor and malignant lymphoma) were discussed. In order to improve the prognosis of malignant brain tumor patients, many clinical trials have been conducted. The most acceptable treatment for malignant glioma is surgical resection plus radiochemotherapy with ACNU. A multidisciplinary approach to treatment is important for control of metastatic brain tumors. Treatment of malignant lymphoma includes radiotherapy and chemotherapy in combination. Combination chemotherapy with CHOP is more effective for malignant lymphoma.

Brain Neoplasms↗

PubMed1994

[Pharmacodynamic study of mitomycin C mixed with fibrin glue for treatment of malignant brain tumors].

The chemotherapy for malignant brain tumors creates two major problems to be solved viz systemic toxicity and interference by the blood brain barrier. The interstitial chemotherapy with sustained release of anticancer drugs has been widely investigated to overcome these problems. The Mitomycin C (MMC) - contained fibrin glue might be a promising candidate for use in local chemotherapy of malignant brain tumors. We investigated pharmacokinetics of the MMC-contained fibrin clot in vitro, activity of the MMC for the cultured glioma cell line, and its effect on the normal mouse brain. The MMC concentration in saline was measured up to 96 hours after the placement of fibrin glue into 5, 10 and 15 ml of saline. Then we periodically replaced the saline to keep the concentration difference of the MMC between the saline and the fibrin clot and evaluated the dissolution of the MMC for 288 hours. The potency of the MMC to suppress the rat glioma cell line was measured after being dissolved from the MMC-contained fibrin clot. The effects of the MMC-contained fibrin clot were histologically evaluated. The MMC-contained fibrin glue, the MMC solution and the fibrin glue were separately injected into the mouse brains. Mice were sacrificed 24, 72, 168 and 336 hours after the injection and brains were examined with photomicroscopy. The MMC was released into the saline rapidly within 24 hours then gradually released until 96 hours had elapsed. Total amounts of the dissolved MMC were proportional to the amounts in the saline.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1994

[Intracavernous internal carotid artery aneurysm associated with persistent trigeminal artery variant: case report].

The authors report a case of an intracavernous internal carotid artery aneurysm associated with a persistent trigeminal artery variant (PTAV). A 47-year-old-woman developed a subarachnoid hemorrhage due to the rupture of aneurysm and underwent direct clipping operation. PTAV is basically an anomalous anastomosis between the internal carotid artery and the anterior inferior cerebellar artery. In this patient, the PTAV originated from the C4 portion of the right internal carotid artery and distributed in the territory of the hemispheric branch of the posterior inferior cerebellar artery. There have been only three reported cases of the internal carotid artery aneurysms arising from the crotch of PTAV. It is also unusual that rupture of such a small aneurysm in the cavernous sinus causes subarachnoid hemorrhage. Embryological development of PTAV and possible mechanism of subarachnoid hemorrhage from the intracavernous aneurysm are discussed.

Aneurysm, Ruptured↗

PubMed1994

[Microcirculatory disturbances in normotensive stage of endotoxin shock].

Red blood cell (RBC) deformability is necessary for maintenance of normal oxygenation in microcirculation. To evaluate oxygen utilization in the early stage of endotoxin shock, we observed RBCs from a rheological point of view in mesenteric microcirculation in rats. Endotoxin shock was induced by Shwaltzman reaction. The velocity of RBC decreased from 1.33 mm.sec-1 to 0.55 mm.sec-1 at 60 min after the provoking injection. RBC could not change its shape in capillaries. In contrast, the mean blood pressure remained at 110 mmHg throughout this observation. In hemorrhagic shock the deformability of RBC in capillaries was not impaired even though mean blood pressure decreased to 43 mmHg. In vitro, we examined the index of RBC deformability with or without endotoxin by the modified Reid's method. The index was decreased significantly by endotoxin. We conclude that impaired deformability of RBC may be a factor of insufficient oxygen utilization in the early stage of endotoxin shock.

Animals↗

PubMed1993

Prognosis of intracranial germ cell tumours: effectiveness of chemotherapy with cisplatin and etoposide (CDDP and VP-16).

A co-operative study for patients with intracranial germ cell tumours was performed to analyze their prognosis and the effectiveness of Cisplatin/Etoposide (CDDP/VP-16) chemotherapy. A total of 46 patients; 30 primary and 16 recurrent cases were registered from 15 participating neurosurgical institutions in Japan. Based on histological criteria and tumour markers, they were classified into three groups; germinoma, germinoma with syncytiotrophoblastic giant cell (STGC), and non-germinomatous malignant tumour. Sixteen patients were treated with CDDP/VP-16 chemotherapy alone and the other 30 patients were treated by a combination of surgery and/or radiation in addition to chemotherapy. Eleven out of 13 patients (85%) with germinoma showed a complete (n = 10) or partial (n = 1) response to CDDP/VP-16 chemotherapy even if their tumours were recurrent and there was evidence of CSF dissemination. For the germinoma with STGC and non-germinomatous malignant tumour, a high response rate; 100% for the former and 78% for the latter, could also be achieved in both the primary and the recurrent cases except in those cases of immature teratoma. Their survival times were still different between them. Two-year survival was 50% in germinoma with STGC and 48% in non-germinoma, while it was 88% in germinoma cases.

Adolescent↗

PubMed1993

Noonan phenotype associated with intracerebral hemorrhage and cerebral vascular anomalies: case report.

A case of a 19-year-old man with multiple characteristics of the Noonan phenotype and a massive intracerebral hemorrhage in the left putaminal region is presented. The hemorrhage was removed surgically, and the patient made a good recovery and was finally able to walk unassisted. Postoperative cerebral angiograms revealed various vascular anomalies, including a small aneurysm. To the best of our knowledge, this is the second detailed case report of an association of the Noonan phenotype with cerebral vascular anomalies presenting intracerebral hemorrhage. The etiology of this syndrome remains unknown but the possible causes of this rare association are discussed.

Adult↗

PubMed1993

The expression of c-kit protein in human adult and fetal tissues.

The c-kit proto-oncogene encodes a tyrosine kinase receptor and is allelic with the dominant white-spotting (W) locus of the mouse. In this study we investigated the expression of human c-kit protein in various adult and fetal human tissues immunohistochemically using anti-human c-kit monoclonal antibody. To discriminate c-kit+ cells from mast cells expressing c-kit, mast cells were identified by staining with Toluidine blue. In oogonia, spermatogonia and skin melanocytes of the fetus and in oocytes of adult ovary, c-kit expression was detected. In adult uterus, c-kit+ cells were widely distributed in the basal layer of the endometrium, myometrium and cervix, the number and distribution being almost identical to those of mast cells. In fetal uterus, c-kit+ non-mast cells clustered beneath the epithelium and a few mast cells were observed in the myometrium and subserosal layer. In both adult and fetus, c-kit+ non-mast cells were detected within smooth muscle layers of the intestine, colon and oesophagus, while mast cells were observed in the mucosal and submucosal layers of these organs. In contrast to mice, no expression of c-kit protein was detected in the human placenta and decidua. Thus, the distribution of c-kit+ cells in various tissues is similar but not identical between adult and fetus and between human and mouse.

Adult↗

PubMed1993

Human leukocyte antigen-DR is a differentiation antigen for human granulosa cells.

We raised a murine monoclonal antibody, OG-3, which reacts with human granulosa cells. Immunohistologically, OG-3 antigen was weakly expressed on the granulosa cells of some growing and atretic follicles, but not on those of preovulatory follicles. After ovulation, the antigen expression rapidly increased on granulosa cells during corpus luteum formation. The antigen expression on granulosa/large luteal cells decreased in the mid-luteal phase, but increased again in the late luteal phase. In early pregnancy, OG-3 antigen expression on large luteal cells increased after 7 wk of gestation. The OG-3 antigen distribution in various organs resembled that of human leukocyte antigen (HLA) class II molecules. An HLA-class II-positive human B cell line (AKIBA) and a murine L-cell transfectant expressing HLA-DR antigen were positive for OG-3 antigen, whereas an HLA-class II-negative human T-cell line and L-cell transfectants expressing HLA-DP and DQ antigens were negative. The molecular mass of OG-3 antigen purified from AKIBA cells was 32-35 kDa. The staining profiles in ovaries with anti-HLA-DR or anti-HLA-class II antibodies were similar to that with OG-3. These results indicate that OG-3 antigen is identical to HLA-DR, and that HLA-DR is a differentiation antigen for human granulosa cells.

Adult↗

PubMed1993

Primary malignant tumor of the fallopian tube: appearance at CT and MR imaging.

Primary malignancy of the fallopian tube is a rare entity. To determine the radiologic characteristics of the tumor, 10 patients with pathologically confirmed fallopian tube malignancy (nine with adenocarcinoma and one with mixed müllerian tumor) underwent magnetic resonance (MR) imaging and computed tomography (CT). With both CT and MR imaging, the lesion appeared relatively small, solid, and lobulated when not associated with hydrosalpinx. At CT, the lesion had an attenuation equal to that of other nonspecific soft-tissue masses and enhanced less than myometrium. On T1-weighted MR images the tumor was usually hypointense, and on T2-weighted images the tumor was most often homogeneously hyperintense. Associated CT and MR imaging findings were peritumoral ascites (four cases), intrauterine fluid collection (two cases), and hydrosalpinx (one case). MR findings allowed the lesion to be distinguished from uterine leiomyoma in three cases in which pelvic examination, ultrasound, and CT findings were equivocal.

Adenocarcinoma↗

PubMed1993

Sustained uterine contractions: a cause of hypointense myometrial bulging.

Fifteen pregnant women were studied with magnetic resonance (MR) imaging. In 14 women, the myometrium exhibited distinct hypointense bulging on T2-weighted images that distorted the gestational sac and decidua but not the outer uterine coutour. In 12 women, an obvious discrepancy was observed between the inner myometrial configuration on T1-weighted images and that on intermediate and T2-weighted images. In three women who underwent serial T2-weighted studies separated by about 30 minutes during one MR examination, hypointense myometrial bulging was observed at a different site on each study. In two women who underwent follow-up MR study within a week after dilation and curettage, the previously distinct hypointense bulging completely disappeared. These findings confirm the transient and mobile nature of this myometrial bulging. This phenomenon can be attributed to sustained uterine contractions, which partially force the blood out of the uterus. The decrease in blood volume results in a decrease in water content, which accounts for the decrease in myometrial signal intensity on T2-weighted images.

Adult↗

PubMed1993

Clinical analysis of incidentally discovered unruptured aneurysms.

BACKGROUND AND PURPOSE: We analyzed the risk factors for rupture of an intracranial aneurysm based on a retrospective angiographic study of ruptured and unruptured aneurysms. METHODS: The 44 cases of asymptomatic aneurysms were selected from 1612 patients whose lesions had been discovered fortuitously by angiography (2.7%) during the period from 1980 to 1989. All these patients were free from any sign of intracranial aneurysm. The variations in age, sex, and location of the aneurysms were analyzed compared with 638 ruptured aneurysms that had been treated in our institute during the same period. The size, shape, and arterial geometry of the unruptured aneurysms were examined angiographically. RESULTS: Unruptured aneurysm was discovered fortuitously in 44 (2.7%) of 1612 patients, with greater incidence in women aged older than 60 years. Unruptured aneurysms were less likely to occur in the anterior communicating artery (12.8%) and the middle cerebral artery (6.4%). However, they were frequently found in the internal carotid artery, with an incidence of 10.6% in cavernous portion of the internal carotid artery, 19.1% in the internal carotid-ophthalmic artery, 19.1% in the internal carotid-posterior communicating artery, and 12.8% in the internal carotid-anterior choroidal artery. Seven of the nine internal carotid-posterior communicating artery aneurysms showed a hypoplastic or aplastic posterior communicating artery. The mean diameter of the unruptured aneurysms was 4.8 mm, and 80% were smaller than 6 mm. CONCLUSIONS: Intracranial aneurysms are formed not only at the bifurcation of an artery but also at its branching and bending points. However, an aneurysm located at the bifurcation, such as the anterior communicating artery and the middle cerebral artery, bleeds easily in contrast with lateral aneurysms such as those found at the branching and bending points on the internal carotid artery.

Adolescent↗

PubMed1993

Selective venous sampling directly from cavernous sinus in Cushing's syndrome.

Using superselective catheterization technique, venous sampling directly from the cavernous sinus was performed in seven patients with Cushing's disease and one patient with ectopic ACTH secreting tumor. In Cushing's disease the central/peripheral (c/p) gradients of ACTH in the cavernous sinus (11.9-111.1; mean, 49.6) were much greater than those in the inferior petrosal sinus (1.0-52.0; mean, 14.0). The intercavernous gradients of ACTH provided correct lateralization in all patients but one who had a midline tumor. A patient with ectopic ACTH secreting tumor showed no gradients of ACTH both in the cavernous sinus and in the inferior petrosal sinus. The c/p gradients of PRL were smaller than those of ACTH in the cavernous sinus, inferior petrosal sinus, and jugular vein. The gradients of ACTH and PRL essentially indicated the same laterality in Cushing's disease, whereas the intersinus gradient of PRL provided a false laterality in two patients with a midline tumor. No complications have been observed during and after the sampling procedure. Thus, we conclude that 1) the selective sampling directly from the cavernous sinus offers sufficient c/p gradients (more than 10) for the reliable diagnosis of Cushing's disease, 2) CRH stimulation during the sampling and the simultaneous measurement of PRL are not necessary in this method, 3) the high concentration of pituitary hormones obtained by this sampling may be useful for other clinical investigations.

Adrenocorticotropic Hormone↗

PubMed1993

A differentiation-related molecule on the cell surface of human granulosa cells.

We raised a monoclonal antibody (OG-1) specifically reactive to human ovarian granulosa cells. Indirect immunofluorescence staining of freshly isolated granulosa cells from preovulatory follicles showed the OG-1 antigen on the cell surface of granulosa cells. The antigen was purified from granulosa cells by immunoaffinity chromatography. Under reducing or nonreducing conditions, the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile of the purified antigen showed two specific protein bands, corresponding to mol wt of 125 and 145 kilodaltons. Immunohistologically, the OG-1 antigen on granulosa cells of primary follicles seemed to increase during follicular development. After ovulation, the antigen was detected on granulosa cells during corpus luteum formation. The antigen expression began to decrease on corpus luteum days 10-12 and disappeared on corpus luteum days 13-14. Luteal cells of pregnancy did not express the OG-1 antigen. Granulosa cells in atretic follicles expressed the OG-1 antigen. On the contrary, thecal or small luteal cells did not express it throughout the menstrual cycle. These results indicate that OG-1 antigen is a differentiation-related surface antigen of human granulosa cells.

Adult↗

PubMed1993

Prepubescent pituitary null cell macroadenoma with silent macroscopic apoplexy: case report.

Secreting pituitary adenomas have marked prevalence in pediatric adenomas. We described a case of an 11-year-old boy with pituitary null cell macroadenoma with silent macroscopic pituitary apoplexy. The patient was admitted with bitemporal hemianopsia and a gradual deterioration of visual acuity. An endocrinological study revealed a low concentration of testosterone and in the plasma a decreased response of luteinizing hormone and follicle-stimulating hormone to luteinizing hormone-releasing hormone. This patient may be the first case of prepubescent null cell macroadenoma confirmed with immunohistochemical study in addition to the findings of classical histopathology.

Adenoma, Chromophobe↗

PubMed1993

Effect of chemoradiotherapy using ACNU, vincristine, and nicardipine with high-dose irradiation on malignant astrocytomas.

Fifty-two patients with malignant astrocytoma were treated with cellular synchronization radiation therapy at the University of Tokyo Hospital between 1977 and 1989. Twenty-five patients (Group 1) received 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3- nitrosourea hydrochloride (ACNU), vincristine, and 60 Gy of irradiation, and 27 patients (Group 2) ACNU, vincristine, the Ca-channel blocker nicardipine, and 72 Gy of irradiation. Median survival times for Groups 1 and 2 were 15 and 30 months, respectively. Although there was no significant difference, Group 2 achieved longer survival with 1-, 2-, and 3-year survival rates of 85.2, 65.8, and 46.9% compared to rates of 66.7, 40.0, and 26.7%, respectively, for Group 1.

Adolescent↗