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K Takakura

Publications and source records attributed to K Takakura.

At least 19 recordsLinked to original sources
PubMed1992

Identification of 7 alpha-hydroxy-3-oxo-4-cholestenoic acid in chronic subdural hematoma.

We detected a novel kind of bile acid in the content of chronic subdural hematoma. This substance was specifically found in chronic subdural hematoma, and not in subdural hygroma, which is pathologically similar except for the lack of capsular membrane. The compound was identified as 7 alpha-hydroxy-3-oxo-4-cholestenoic acid by high performance liquid chromatography, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectrometry. The structure was confirmed by the comparison with the chemically synthesized compound. The average contents in chronic subdural hematoma were 658.09 +/- 137.53 ng/ml, while those in normal human plasma were 126.27 +/- 17.73 ng/ml. It was not detected in normal cerebrospinal fluid. The higher level in chronic subdural hematoma than human plasma strongly suggests the local, extrahepatic production of this type of C27 bile acids.

Bile Acids and Salts↗
PubMed1992

Application of superfine fiberscope for endovasculoscopy, ventriculoscopy, and myeloscopy.

In the past three years, we have used a superfine fiberscope for endovasculoscopy, ventriculoscopy, and myeloscopy. Flexible superfine fiberscope, 0.75 mm in outer diameter, could visualize various intravascular findings. In in-vivo canine experiment, sequential changes of thrombus produced by endothelial abrasion by needle or balloon in the canine carotid artery can be clearly seen. And thrombolysis by focal arterial injection of tissue plasminogen activator was sequentially observed. In the clinical study, we could evaluate the stenotic lesions of the subclavian and vertebral arteries before and after balloon angioplasty. During ventriculoscopy, a 2 mm of mini-caliber fiberscope was introduced under ultrasound monitoring, and provided clear visualization of intraventricular tumours. In myeloscopy, draining veins of arteriovenous malformations and nerve roots of the cauda equina could be clearly seen by flexible fiberscope. From these results, it can be said that the superfine fiberscope provides clear and useful visualizations of the interior of vessels, ventricles, and the intrathecal area of the spinal canal. The new applications of this superfine fiberscope for minimally invasive neurosurgery may bring about a marked improvement of therapeutic results.

Animals↗
PubMed1992

Inverse dose-rate effect of DNA breaks and inactivation of transforming activity induced by tritiated water and 60Co gamma-rays.

When an aqueous solution of plasmid DNA at a constant low concentration of 5 micrograms/cm3 was irradiated with 60Co gamma-rays, D37 dose of single-strand breaks was decreased from 18 Gy at a dose-rate of 6.77 Gy/h of acute irradiation to 2.3 Gy at a dose-rate of 0.00212 Gy/h. Or G value was increased from 0.0010 to 0.0081. Similar dose-rate dependency of D37 dose and G value were also found when the plasmid DNA solution was treated with various concentrations of tritiated water at various dose-rates, ranging from 5.13 Gy/h to 0.000118 Gy/h. RBE of tritium beta-rays for single-strand breaks was ranged from 0.3 to 0.5 in a wide range of dose-rates. When the DNA solution was saturated with argon to remove oxygen, the dose-rate dependency of gamma-rays was abolished and that of tritium beta-rays was significantly suppressed. When the DNA solution in air was kept at 4 degrees C for 50 h or 25 days after acute irradiation, the G value of DNA breaks was the same as that kept at -20 degrees C for the same period, but much lower than that of the solution irradiated for the same period at a lower dose-rate to give the same total doses. This shows that the inverse dose-rate effect could not be induced from the different exposure periods but from continuous irradiation of different dose-rates. The inverse dose-rate effect for inactivation of transforming activity of DNA irradiated with tritiated water was also observed in the range from 0.0588 Gy/h to 0.00118 Gy/h.

Cobalt Radioisotopes↗
PubMed1992

Immunohistochemical localization of androgen receptor in the human endometrium, decidua, placenta and pathological conditions of the endometrium.

The immunohistochemical localization of the androgen receptor in the human endometrium at various stages of the menstrual cycle and post-menopausal period, in decidua and placenta of early pregnancy, and in several pathological conditions of the endometrium has been investigated. At any phase of the menstrual cycle, both endometrial glandular cells and endometrial stromal cells showed positive nuclear staining. Endometrial stromal cells of the functional layer showed stronger staining than those of the basal layer, but endometrial glandular cells of both layers showed the same staining intensity. There was little staining in myometrium. Even after menopause, endometrial glandular and stromal cells showed the same staining pattern as the basal layer of pre-menopausal endometrium and the staining intensity of endometrial stromal cells was weak. In decidua and placenta of early pregnancy, decidual and trophoblastic cells showed positive staining and there was no staining in the stromal cells of placenta. The expression of the androgen receptor was also detected in adenomyosis, endometriosis and endometrial carcinoma. Although the proliferation and differentiation of endometrium are mediated mainly by oestrogen and progesterone receptors, the androgen receptor may play some role in modulating these changes. These results suggest that it may be involved in both physiological and pathological changes of the endometrium.

Adult↗
PubMed1992

Immunohistochemical localization of androgen receptor in the human ovary throughout the menstrual cycle in relation to oestrogen and progesterone receptor expression.

In order to elucidate the role of androgen receptors (AR) in human ovaries, we examined their immunohistochemical localization, in comparison with oestrogen receptors (ER) and progesterone receptors (PR), at various stages of the menstrual cycle and follicular development. Primordial and primary follicles did not express AR. In granulosa and thecal cells of secondary follicles there was weak nuclear staining for AR. Granulosa cells of dominant follicles showed moderate nuclear staining for AR, which was stronger than that in thecal cells. In the luteal phase, the staining intensity for AR was strongest in the early luteal phase just after ovulation and declined gradually thereafter. Thecal cells of atretic follicles showed moderate nuclear staining for AR, which was a little stronger than that in dominant follicles. There was weak nuclear staining for AR in stromal cells surrounding follicles. Though there was variation in the staining intensity, AR were present at almost all stages of the menstrual cycle. There is a possibility that androgens, mediated by AR, may play an essential role in follicular growth and maturation, atresia and luteinization as autocrine or paracrine agents.

Adult↗
PubMed1992

Dipeptidyl peptidase IV as a differentiation marker of the human endometrial glandular cells.

To investigate the involvement of membrane-bound peptidases in the human endometrial function, we examined the expression of dipeptidyl peptidase (DPP) IV and its enzyme activity. Immunohistological studies revealed that DPP IV was detected on human endometrial glandular cells and endometrial surface epithelium, but not on endometrial stromal cells or decidual cells in the first trimester of pregnancy. DPP IV expression on glandular cells and surface epithelium was weak in the proliferative phase, began to increase gradually in the early secretory phase, and was strong in mid-to late secretory phase and in the first trimester of pregnancy. DPP IV enzyme activity was detected histochemically in glandular cells and surface epithelium in the mid-secretory phase, and became stronger in the late secretory phase, but was rarely detected in the proliferative phase and early secretory phase. During the first trimester of pregnancy DPP IV enzyme activity in glandular cells and surface epithelium was slightly weaker than in the late secretory phase. Endometrial stromal cells and decidual cells, however, had no detectable DPP IV enzyme activity at any time throughout the menstrual cycle or during the first trimester of pregnancy. These findings indicate that DPP IV is a differentiation marker for glandular cells and surface epithelium and that active DPP IV is present in both areas during the peri-implantation period and thereafter.

Adult↗
PubMed1992

Expression of aminopeptidase N and neutral endopeptidase on the endometrial stromal cells in endometriosis and adenomyosis.

Indirect immunofluorescence staining revealed that endometrial stromal cells (ESC) in the ectopic endometrium of patients with endometriosis or adenomyosis expressed aminopeptidase N/cluster of differentiation (CD) 13 antigen and neutral endopeptidase/CD10 antigen, both of which are expressed on ESC in the normal endometrium throughout the menstrual cycle. Thus, ESC in the ectopic endometrium resembled ESC in the normal endometrium not only morphologically but also antigenically. Both peptidase antigens may be useful markers for the histological diagnosis of endometriosis and adenomyosis.

Adult↗
PubMed1992

Human endometrial stromal cells and decidual cells express cluster of differentiation (CD) 13 antigen/aminopeptidase N and CD10 antigen/neutral endopeptidase.

With specific monoclonal antibodies, we found that human endometrial stromal cells and decidual cells express two function-related surface antigens. Indirect immunofluorescence staining revealed that both endometrial stromal cells and decidual cells during the first trimester of pregnancy expressed cluster of differentiation (CD) 13 antigen and CD10 antigen, which are identical to aminopeptidase N and neutral endopeptidase, respectively. By flow cytometric analysis, CD13 antigen was detected on 82-93% of the examined cells, and CD10 antigen was detected on 75-93% of the examined cells in endometrial stromal cell-enriched preparations. Furthermore, peptidase activity was detected in these cell preparations by an assay based on the hydrolysis of alanine-p-nitroanilide into p-nitroaniline and alanine.

Adult↗
PubMed1992

Expression of c-kit protein during placental development.

The c-kit proto-oncogene encodes a transmembrane tyrosine kinase receptor and is shown to be allelic with the white-spotting locus (W) of the mouse. In order to elucidate the role of c-kit protein during placental development, we have examined the expression of c-kit protein in the uterus and placenta of mice at pre- and post-implantation stages by the avidin-biotin-peroxidase (ABC) method using rat anti-mouse c-kit monoclonal antibody. At Days 3 and 5 of pregnancy and pseudo-pregnancy, c-kit protein was detected in the glandular epithelium, but little expression was observed in the luminal epithelium. At Day 7 of pregnancy, expression was detected in the stromal cells around the uterine crypts of the mesometrial portion, but not in the vigorously proliferating decidual cells around the developing embryo. At Days 9 and 10 of pregnancy, the decidua basalis facing invading trophoblasts gradually expressed c-kit protein. In the mature placenta, c-kit protein was detected in the labyrinthine and decidual layers, but in neither the giant trophoblastic nor the spongiotrophoblastic layer. By Northern blotting and reverse transcriptase-polymerase chain reaction (RT-PCR), c-kit mRNA was detected at the stages of periimplantation and placental development. These results suggested that the c-kit protein might be involved in the proliferation and differentiation of placenta.

Animals↗
PubMed1992

Differential expression of aminopeptidase-N on human ovarian granulosa and theca cells.

The expression of aminopeptidase-N and neutral endopeptidase in human ovarian tissue was examined using specific monoclonal antibodies for each of these peptidases and histochemical staining for enzyme activity. Aminopeptidase-N is a membrane-bound metalloprotease catalyzing the removal of N-terminal amino acids from peptides and was detected by immunofluorescence staining on theca interna cells in secondary follicles and on luteinized thecal cells in preovulatory follicles and corpora lutea. However, aminopeptidase-N was not detected on granulosa cells. Peptidase activity was also detected by histochemical staining on theca interna cells and luteinized thecal cells. Luteinized granulosa cells showed peptidase activity, despite the lack of aminopeptidase-N. Neutral endopeptidase was not detected in ovarian granulosa and thecal cells. These observations indicate that aminopeptidase-N can be a useful surface marker for thecal cells.

Adult↗
PubMed1992

Cytokine modulation of progesterone and estradiol secretion in cultures of luteinized human granulosa cells.

To clarify the possible roles of cytokines in the regulation of luteal cell function, we examined the effects of interferon (IFN), interleukin-1 (IL-1), and tumor necrosis factor (TNF) on progesterone and estradiol secretion in cultures of luteinized human granulosa cells. IFN gamma reduced hCG-stimulated progesterone secretion in a concentration-dependent manner; at its maximal inhibitory concentration (10 ng/mL), IFN gamma reduced progesterone secretion to 20% of that in the hCG-stimulated controls. Whereas other IFN (alpha and beta) reproduced the inhibitory effect of IFN gamma, IL-1 and TNF had no effect on hCG-stimulated progesterone secretion at concentrations of 1 and 10 ng/mL. IFN gamma also markedly reduced FSH-stimulated estradiol secretion. Unlike their effects on hCG-stimulated progesterone secretion, IL-1 and TNF reproduced the inhibitory effect of IFN gamma on FSH-stimulated estradiol secretion. IFN gamma significantly reduced both hCG- and FSH-stimulated cAMP generation in granulosa cells. IL-1 and TNF inhibited FSH-stimulated cAMP generation, but they did not inhibit hCG-stimulated cAMP generation. None of these cytokines reduced forskolin-stimulated cAMP generation, thus suggesting that these cytokines affect steps proximal to cAMP generation without affecting cAMP generation itself. IFN gamma also reduced progesterone secretion in response to (Bu)2cAMP, suggesting that it also affects steps distal to cAMP generation. This study has demonstrated that cytokines modulate the steroidogenesis of luteinized human granulosa cells in vitro; the results suggest that cytokines may play permissive roles in regulating luteal cell function.

Adult↗
PubMed1992

Human luteal cells express dipeptidyl peptidase IV on the cell surface.

We previously reported that human theca interna cells and small luteal cells express membrane-bound aminopeptidase N, and suggested that membrane-bound peptidases are involved in folliculogenesis and luteal function by regulating extracellular peptide concentrations. In this study, we examined the expression of dipeptidyl peptidase IV (DPP IV), which is a membrane-bound peptidase and has its catalytic domain at extracellular sites, in human granulosa cells, thecal cells of growing, preovulatory, and atretic follicles, as well as corpora lutea. Indirect immunofluorescence staining of ovarian tissues with specific monoclonal antibodies revealed that DPP IV was present in large and small luteal cells in corpora lutea. DPP IV peptidase activity was also detected histochemically in corpora lutea. In growing, preovulatory, and atretic follicles, there was weak immunoreactivity and DPP IV peptidase activity on luteinized theca interna cells, but not on granulosa cells. The expression of DPP IV on the cell surface of large and small luteal cells was confirmed by indirect immunofluorescence staining of freshly isolated luteal cells. These results indicate that DPP IV is a useful surface differentiation marker of human luteal cells and suggest that peptidases are involved in luteal function.

Adult↗
PubMed1992

Ganglioside composition and its relation to clinical data in brain tumors.

The ganglioside composition of 15 cases of meningioma, 15 cases of astrocytoma, 5 cases of neurinoma, 4 cases of ependymoma, 3 cases of metastatic brain tumor and 1 case each of mixed glioma, oligodendroglioma, medulloblastoma, embryonal carcinoma, and cultured glioma cell line were analyzed by thin-layer chromatography. The GM2, GD3, and GD2 content of the tumors was determined using specific monoclonal antibodies (MAb). Cases were grouped according to the difference in ganglioside pattern and various clinical features. In meningiomas and astrocytomas, GM3 and GD3 were the major gangliosides. The tumor content of the rather simple gangliosides (GM3, GM2, GD3, GD2) increased or was almost equal to that of normal tissue (leptomeninges tissue in the case of meningiomas, and brain tissue in the case of astrocytomas), while the tumor content of complex gangliosides (GM1, GD1a, GT1a, GT1b) decreased as compared with normal tissue. The GM3 content of meningiomas increased in middle-aged patients, who comprised the majority of the patients with these tumors. The GD2 content decreased in middle-aged patients with initial symptoms of meningioma within a year. The GM3 content of astrocytomas decreased in patients who underwent radiotherapy. The amount of GM3 and GD3 increased in small tumors. GM3 may be related to the early proliferative stage. The ganglioside patterns of brain tumors are shown in this study to differ according to clinical features and also to be changeable in their clinical courses.

Aging↗
PubMed1992

Radiotherapy for pediatric brain stem glioma: radiation dose, response, and survival.

An analysis of 39 patients under 20 years of age with brain stem glioma treated with radiotherapy between 1977 and 1991 was undertaken. Twenty-eight (71.2%) of the patients responded well to initial radiotherapy, and 11 (28.8%) responded poorly. Median survival for the total patient population was 10 months. Response rates and median survivals were influenced by radiation dose: 45.5% and 9 months at doses less than 4499 cGy (n = 11), 83.3% and 13 months at doses between 4500 and 5499 cGy (n = 12), 66.7% and 11.5 months at doses between 5500 and 6499 cGy (n = 9), and 100% and 10 months at doses more than 6500 cGy (n = 7). Multivariate analysis revealed the response to initial radiotherapy was the only predictor of survival with radiation doses up to 6499 cGy. Four of the patients who responded well demonstrated radiological and/or histological calcification within or around the tumor at the time of clinical deterioration. Radiation injury was confirmed in two autopsy cases. The possibility that intratumoral radiation injury causes clinical deterioration is suggested.

Adolescent↗
PubMed1992

Effect of AT877 on cerebral vasospasm after aneurysmal subarachnoid hemorrhage. Results of a prospective placebo-controlled double-blind trial.

With the cooperation of 60 neurosurgical centers in Japan, a prospective randomized placebo-controlled double-blind trial of a new calcium antagonist AT877 (hexahydro-1-(5-isoquinolinesulfonyl)-1H-1,4-diazepine hydrochloride, or fasudil hydrochloride) was undertaken to determine the drug's effect on delayed cerebral vasospasm in patients with a ruptured cerebral aneurysm. A total of 276 patients, who underwent surgery within 3 days after subarachnoid hemorrhage (SAH) of Hunt and Hess Grades I to IV, were entered into the study. Nine patients were excluded because of protocol violation. The remaining 267 patients received either 30 mg AT877 or a placebo (saline) by intravenous injection over 30 minutes, three times a day for 14 days following surgery. Demographic and clinical data were well matched between the two groups. It was found that AT877 reduced angiographically demonstrable vasospasm by 38% (from 61% in the placebo group to 38% in the AT877 group, p = 0.0023), low-density regions on computerized tomography associated with vasospasm by 58% (from 38% to 16%, p = 0.0013), and symptomatic vasospasm by 30% (from 50% to 35%, p = 0.0247). Furthermore, AT877 reduced the number of patients with a poor clinical outcome associated with vasospasm (moderate disability or worse on the Glasgow Outcome Scale at 1 month after SAH) by 54% (from 26% to 12%, p = 0.0152). There were no serious adverse events reported in the AT877 group. This is the first report of a placebo-controlled double-blind trial that has demonstrated a significant reduction in angiographically revealed vasospasm by intravenous drug therapy.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1992

Rebleeding from vertebral artery dissection after proximal clipping. Case report.

The authors present the case of a patient with vertebral artery dissection that rebled after being treated by proximal clipping. This is the second report of such a case. The results indicated that proximal clipping is not free from the risk of rebleeding, and a better alternative surgical technique should always be sought when treating vertebral artery dissections.

Adult↗
PubMed1992

[Preliminary clinical trial of intrathecal rt-PA (TD-2061) for the prevention of cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage].

The results of preliminary clinical trial (a multicenter, open-label, dose escalation study) of intrathecal recombinant tissue plasminogen activator (rt-PA) for the prevention of cerebral vasospasm were reported. Seventeen patients admitted within 48 hours of subarachnoid hemorrhage (SAH) were enrolled in this study. Patients ranged from 42 to 69 years of age. All cases enrolled were classified in clinical grade II, III or IV according to the classification of Hunt and Kosnik and in group 3 or 4 according to Fisher's CT grading scale. Surgery for clipping the aneurysms were performed and a small silicone catheter was left in the subarachnoid space. Twenty four hours after the surgery intrathecal bolus infusion of rt-PA was started through the silicone catheter at 6-hour intervals for 3 days. Patients were divided into 4 groups based on the dosage of rt-PA for each infusion. The dosage of rt-PA for each infusion and a number of cases in each group was as follows; 25 KIU in 4 cases, 75 KIU in 6 cases, 200 KIU in 4 cases and 600 KIU in 3 cases. There was no significant difference in the clearance of subarachnoid clots between four groups. However, the occurrence of both symptomatic and angiographic vasospasm was less in the 75 KIU group than in other three groups. Intracranial bleeding complications were noted in 4 patients (1/6 in the 75 KIU group, 2/4 in the 200 KIU group and 1/3 in the 600 KIU group). Serial coagulation studies demonstrated no evidence of systemic fibrinolysis. Disorientation was noted in 2 out of 3 patients of the 600 KIU group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗