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Biomedical subjects

N Takai

Publications and source records attributed to N Takai.

At least 19 recordsLinked to original sources
PubMed2006

Beta-hydroxyisovalerylshikonin induces apoptosis and G0/G1 cell-cycle arrest of endometriotic stromal cells: a preliminary in vitro study.

BACKGROUND: Most of the current medical treatments for endometriosis aim to down-regulate the estrogen activity. However, a high recurrence rate after medical treatments has been the most significant problem. Beta-hydroxyisovalerylshikonin (beta-HIVS) is an ATP non-competitive inhibitor of protein-tyrosine kinases and is considered an apoptosis-inducing agent. The aim of this study is to evaluate the effects of beta-HIVS on the proliferation, cell cycle and apoptosis of endometriotic stromal cells. METHODS: We investigated the effects of beta-HIVS on cultured ovarian endometriotic cyst stromal cells (ECSC) by a modified methylthiazoletetrazolium (MTT) assay, a 5-bromo-2'-deoxyuridine (BrdU) incorporation assay and internucleosomal DNA fragmentation assays. The effect of beta-HIVS on the cell cycle of ECSC was determined by flow cytometry. The expression of apoptosis-related molecules was examined in ECSC using western blot analysis. RESULTS: Beta-HIVS significantly inhibited the proliferation and DNA synthesis of ECSC and induced apoptosis and G0/G1 phase cell-cycle arrest of these cells. Down-regulation of the B-cell lymphoma/leukaemia-2 (Bcl-2) expression with the activation of caspase-3, caspase-8 and caspase-9 was observed in ECSC after beta-HIVS treatment. CONCLUSIONS: These results suggest that beta-HIVS induces apoptosis of ECSC by suppressing anti-apoptotic proteins. Although our present findings are preliminary, beta-HIVS could potentially be a therapeutic agent for the treatment of endometriosis.

Apoptosis↗
PubMed2002

Complete response to radiation therapy in a patient with chemotherapy-resistant ovarian clear cell adenocarcinoma.

Recurrent ovarian cancer after front-line chemotherapy is incurable. In most institutions, chemotherapy is continued as salvage therapy after primary chemotherapy failure and despite the fact that long-term survival and complete responses are infrequent. Radiation therapy for patients with recurrent ovarian cancer has often been done with palliative intent. A patient with ovarian clear cell adenocarcinoma received irradiation with palliative intent to the whole pelvis after chemotherapy (paclitaxel, carboplatin, and irinotecan) produced no effect. Although she developed a rectovaginal fistula due to cancer invasion during radiation therapy. One year and half after the therapy, she is still alive with no evidence of disease. In an effort to maximize salvage potential and quality of life while minimizing toxicity, selected patients with ovarian cancer should be treated with radiation therapy directed to residual or recurrent sites.

Adenocarcinoma, Clear Cell↗
PubMed2002

Significance of fractionated irradiation for the biological therapeutic gain of carbon ions.

It is well established that the RBE (relative biological effectiveness) for cell killing depends on LET (linear energy transfer), and that a maximum RBE is observed at approximately 150 keV.micron-1. However, the therapeutic gain depends on the ratio of the RBEs for the effects on the cancer cell population and the effects on normal tissues. The RBE of a given radiation quality depends not only on LET but also on dose, biological system and effect, and irradiation conditions. There is no data available to answer the question: which LET is suitable to improve the biological therapeutic gain of carbon ions? Here, three different LET values of 290 MeV/u carbon ions were selected, and the relative biological effectiveness was compared between tumour-growth retardation and skin damage using a murine transplantable tumour. Larger RBE values for tumours after than the skin type were obtained when carbon ions of intermediate LET were delivered daily for 2 to 5 fractions. The biological therapeutic gain would be high for the carbon ion SOBP if the number of fractions were correctly selected in clinical trials.

Animals↗
PubMed2002

c-Ets1 is a promising marker in epithelial ovarian cancer.

c-Ets1 controls the expression of some genes involved in extracellular matrix remodeling. To elucidate the involvement of c-Ets1 in epithelial ovarian carcinogenesis, we investigated the role of the proto-oncogene c-ets1 in the regulation of physiological processes such as cell proliferation, differentiation, and tumor invasion. Using fluorescent immunohistochemistry, we analyzed serial frozen sections for c-Ets1 protein expression in 26 patients with ovarian epithelial carcinoma, 10 patients with benign cystadenoma of the ovary, and 10 premenopausal patients with normal ovaries. We analyzed the relationship between the percentage of c-Ets1 stained cells in a patient and characteristics of the patient including histological classification, clinical stage, histological grade, and clinical outcome. c-Ets1 was not detected in any cases of benign ovarian cystadenoma. Most of the c-Ets1 proteins were found in the cytoplasm and some in the nucleus of epithelial ovarian cancer tissues. Moreover, c-Ets1 was strongly expressed in the head portion of papillary cancer tissues that had invaded the stroma. c-Ets1 expression was significantly associated with clinical stage (p<0.01), histological grade (p<0.01), and clinical outcome (p<0.01). Survival data were available for all patients and univariate Cox regression analysis showed that c-Ets1 expression was significantly associated with a poor prognosis (p<0.05). Our results demonstrate that c-Ets1 expression in epithelial ovarian cancer correlates to the malignant potential of the tumor.

Biomarkers, Tumor↗
PubMed2001

Polo-like kinase (PLK) expression in endometrial carcinoma.

Polo-like kinase (PLK) is a cell cycle-regulated, cyclin-independent serine/threonine protein kinase. Recent reports have shown a critical role for PLK during tumorigenesis. To explore whether PLK plays a general role as a tumor marker of endometrial carcinomas, we examined the expression of PLK mRNA and protein in endometrial carcinomas and normal endometrium, and analyzed the relationship between PLK protein expression and malignant potential. We found that PLK mRNA was expressed in all specimens from endometrial carcinoma patients using RT-PCR methods, although some specimens from normal endometria were negative. Immunohistochemically, most of the PLK was found in the cytoplasm (around the nucleus), and partly in the nucleus of endometrial carcinoma glands and also secreted tissues from endometrial carcinoma glands. PLK was expressed at the basement membrane of carcinoma glands and partly expressed in the head portion of papillary carcinoma tissues. There was a significant correlation between percentages of PLK-positive cells and histological grade of endometrial carcinoma (P<0.0001). However, the expression of proliferating cell nuclear antigen and Ki-67 was independent of PLK expression. Moreover, we noted that PLK is strongly expressed in invading carcinoma cells. PLK expression could reflect the degree of malignancy and proliferation in endometrial carcinoma. Thus, in addition to being of diagnostic value, modulation of PLK activity in the tumors by chemotherapeutic agents or gene therapy may prove to be of therapeutic value.

Adult↗
PubMed2001

Id1 expression is associated with histological grade and invasive behavior in endometrial carcinoma.

Basic helix-loop-helix (bHLH) DNA-binding proteins have been reported to regulate tissue-specific transcription of cellular differentiation within multiple cell lineages. The Id family of helix-loop-helix proteins does not possess a basic DNA-binding domain and functions as a negative regulator of bHLH proteins by forming high-affinity heterodimers with bHLH proteins. Id proteins were originally characterized as inhibitors of DNA binding and cell differentiation. Thus, overexpression of Id proteins correlates with cell proliferation and arrested differentiation in many cell lineages. To elucidate the involvement of Id1 in endometrial carcinogenesis, we analyzed serial frozen sections for Id1 protein expression in 20 cases of endometrial carcinoma and 20 cases of normal endometria by fluorescent immunohistochemistry. We analyzed the relationship between the percentages of Id1-stained cells and the patient's characteristics, including histological grade, clinical stage, presence of invasion to >1/2 myometrium, and clinical outcome. In normal endometria, Id1 was not detected in either the proliferative or the secretory phase. There was, however, abundant Id1 immunoreactivity in the endometrial carcinoma cells. Moreover, Id1 was strongly expressed in the inflammatory cells. Scoring on the basis of the percentage of positive cells indicated that Id1 expression is significantly associated with histological grade (P<0.05) and the presence of invasion to >1/2 myometrium (P<0.05). Our results demonstrate that increased Id1 expression in endometrial carcinoma correlates with the malignant potential of this tumor.

Adult↗
PubMed2001

Expression of chloride channel, ClC-5, and its role in receptor-mediated endocytosis of albumin in OK cells.

By using Western blot and RT-PCR analyses, the expression of ClC-5, a member of the ClC family of voltage-gated chloride channels, and its mRNA was detected in OK cells. The effect of chloride channel inhibitors on receptor-mediated endocytosis of albumin was examined in OK cells and compared to that of vacuolar H(+)-ATPase inhibitors. Accumulation of fluorescein-isothiocyanate (FITC)-albumin, a receptor-mediated endocytosis marker, was inhibited by 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB), a chloride channel inhibitor, in a concentration-dependent fashion. In contrast, uptake of FITC-inulin, a fluid-phase endocytosis marker, was not affected by NPPB. Other chloride channel inhibitors, 4,4'-diisothiocyanatostilbene-2-2'-disulfonic acid and diphenylamine-2-carboxylic acid, also inhibited FITC-albumin uptake. NPPB, as well as a vacuolar H(+)-ATPase inhibitor bafilomycin A(1), caused a decrease in the affinity and in the maximal velocity of FITC-albumin uptake. These results suggest that chloride channel, most likely ClC-5, plays an important role in the receptor-mediated endocytosis of albumin in OK cells.

Albumins↗
PubMed2001

Expression of polo-like kinase in ovarian cancer is associated with histological grade and clinical stage.

Polo-like kinase (PLK), a cell cycle-regulated, cyclin-independent serine/threonine protein kinase, has been shown in recent reports to play a critical role during tumorigenesis. To investigate whether PLK plays a general role as a tumor marker of ovarian cancers, we examined the expression of PLK protein in ovarian cancers, and analyzed the relationship between PLK protein expression and histological grade. Immunohistochemically, the majority of PLK was found in the cytoplasm (around the nucleus), and a portion was found in the nucleus of ovarian cancer glands and also in the fluid secreted from these glands. PLK was expressed at the basement membrane of cancer glands and partly expressed in the head portion of papillary cancer tissues. A significant correlation was found between percentages of PLK-positive cells and histological grade of ovarian cancer (P<0.001). However, the expression of proliferating cell nuclear antigen, Ki-67, and cyclin B1 was independent of PLK expression. Taken together, these findings suggest that PLK expression may reflect the degree of malignancy rather than the degree of proliferation in ovarian cancer. Thus, in addition to being of diagnostic value, PLK activity in ovarian tumors may be modulated by chemotherapeutic agents or gene therapy to therapeutic effect.

Adenocarcinoma↗
PubMed2001

FTIR spectroscopic analyses of human placental membranes.

We investigated the differences in the Fourier transform infrared (FTIR) spectra of normal and abnormal human placentas. Normal placentas, placentas with infant intrauterine growth restriction (IUGR), and placentas from mothers with diabetes mellitus (DM) were used, none of which had been treated before measurement. The tissues were divided into three parts: the upper one-third portion (P1), the middle portion (P2), and the lower one-third portion (P3). Placental tissues were also investigated histochemically. The differences of the main second-derivative FTIR spectra among P1, P2, and P3 in normal placentas were observed in bands appearing between 1080 and 1090 cm(-1). Bands in P2 were observed at 1083 cm(-1), which was significantly higher than that in P3 (p < 0.05). The spectrum of P2 tissue in placentas with infant IUGR had a peak at 1081 cm(-1), which was significantly different from those of P1 and P3 (p < 0.05). In placentas with DM, the P2 band was shifted to a peak at 1088 cm(-1). These data were well correlated with the histochemical sugar-chain staining pattern of the P2 portion of the placenta. Our data suggested that this IR technique is applicable to the clinical diagnosis of diseases in the gynecological field.

Adult↗
PubMed2001

Expression of cathepsin L in normal endometrium and endometrial cancer.

OBJECTIVE: To evaluate the expression of cathepsin L in normal endometrium and endometrial adenocarcinoma. STUDY DESIGN: Tissue from eight cases of G1 and eight of G2 endometrioid adenocarcinoma, and 15 normal endometrial specimens were examined by immunohistochemistry. RESULTS: In the normal endometrium, cathepsin L was expressed in a few cell layers of the apical part of the glandular epithelium throughout the menstrual cycle. In the carcinomas, there was an inverse correlation between the grade of tumor and the cathepsin L expression. CONCLUSION: Cathepsin L expression may cease during endometrial carcinogenesis and its expression may be less important in tumor progression than it is in tumors of other tissues.

Adenocarcinoma↗
PubMed2001

Dose--response of initial G2-chromatid breaks induced in normal human fibroblasts by heavy ions.

PURPOSE: To investigate initial chromatid breaks in prematurely condensed G2 chromosomes following exposure to heavy ions of different LET. MATERIAL AND METHODS: Exponentially growing human fibroblast cells AG1522 were irradiated with gamma-rays, energetic carbon (13 keV/ microm, 80 keV/microm), silicon (55 keV/microm) and iron (140 keV/microm, 185keV/microm, 440keV/microm) ions. Chromosomes were prematurely condensed using calyculin-A. Initial chromatid-type and isochromatid breaks in G2 cells were scored. RESULTS: The dose response curves for total chromatid breaks were linear regardless of radiation type. The relative biological effectiveness (RBE) showed a LET-dependent increase, peaking around 2.7 at 55-80keV/microm and decreasing at higher LET. The dose response curves for isochromatid-type breaks were linear for high-LET radiations, but linear-quadratic for gamma-rays and 13 keV/microm carbon ions. The RBE for the induction of isochromatid breaks obtained from linear components increased rapidly between 13keV/microm (about 7) and 80keV/microm carbon (about 71), and decreased gradually until 440 keV/microm iron ions (about 66). CONCLUSIONS: High-LET radiations are more effective at inducing isochromatid breaks, while low-LET radiations are more effective at inducing chromatid-type breaks. The densely ionizing track structures of heavy ions and the proximity of sister chromatids in G2 cells result in an increase in isochromatid breaks.

Azure Stains↗
PubMed2001

Ca2+-images of smooth muscle cells and endothelial cells in one confocal plane in femoral artery segments of the rat.

Simultaneous recording of Ca2+-images in one confocal plane from vascular smooth muscle cells (SMCs) and endothelial cells (ECs) of an intact rat femoral artery segment was performed using indo-1 and a confocal microscope. During application of 10 microM acetylcholine (ACh), elevation and oscillation of intracellular Ca2+ concentration ([Ca2+]i) were observed in ECs but not in SMCs. Sequential conduction of Ca2+ oscillation from an EC to the neighboring ECs in one longitudinal direction was often observed in the presence of ACh. On the other hand, the activation of voltage-dependent Ca2+ channels by external 30 mM K+ resulted in the elevation of [Ca2+]i only in SMCs. When 10 microM ACh was added in the presence of 30 mM K+, it was observed in one confocal plane that [Ca2+]i in ECs and SMCs was almost simultaneously increased and decreased, respectively. The simultaneous recording method in this intact preparation will provide a line of valuable information about the interactions between SMCs and ECs, based on spatio-temporal analyses of absolute values of [Ca2+]i in individual cells.

Acetylcholine↗
PubMed2001

Kinetics of chromatid break repair in G2-human fibroblasts exposed to low- and high-LET radiations.

The purpose of this study is to determine the kinetics of chromatid break rejoining following exposure to radiations of different quality. Exponentially growing human fibroblast cells AG1522 were irradiated with gamma-rays, energetic carbon (290 MeV/u), silicon (490 MeV/u) and iron (200 MeV/u, 600 MeV/u). Chromosomes were prematurely condensed using calyculin A. Prematurely condensed chromosomes were collected after several post-irradiation incubation times, ranging from 5 to 600 minutes, and the number of chromatid breaks and exchanges in G2 cells were scored. The relative biological effectiveness (RBE) for initial chromatid breaks per unit dose showed LET dependency having a peak at 55 keV/micrometers silicon (2.4) or 80 keV/micrometers carbon particles (2.4) and then decreased with increasing LET. The kinetics of chromatid break rejoining following low- or high-LET irradiation consisted of two exponential components. Chromatid breaks decreased rapidly after exposure, and then continued to decrease at a slower rate. The rejoining kinetics was similar for exposure to each type of radiation, although the rate of unrejoined breaks was higher for high-LET radiation. Chromatid exchanges were also formed quickly.

Cell Line↗
PubMed2000

Expression of c-Ets1 is associated with malignant potential in endometrial carcinoma.

BACKGROUND: The protooncogene c-ets1 is a transcriptional factor that controls the expression of a number of genes involved in extracellular matrix remodeling. It might play a role in the regulation of physiologic processes such as cell proliferation and differentiation and also is associated with angiogenesis, cell migration, and tumor invasion. METHODS: To elucidate the involvement of c-Ets1 in endometrial carcinogenesis, the authors analyzed serial frozen sections for c-Ets1 protein expression in 20 cases of endometrial carcinoma and 20 cases of normal endometria by fluorescent immunohistochemistry. The authors analyzed the relation between the percentages of c-Ets1 stained cells and patient characteristics including histologic grade, surgical stage, presence of invasion to greater than one-half myometrium, presence of vascular involvement, presence of lymph node metastasis, and clinical outcome. RESULTS: In the normal endometria, c-Ets1 was weakly detected at the luminal surface of endometrial glands in both the proliferative and secretory phases. Most of the c-Ets1 proteins were found in the cytoplasm and partly in the nucleus of endometrial carcinoma glands, and also in fluid secreted from endometrial carcinoma glands. Moreover, c-Ets1 was strongly expressed in the head portion of papillary carcinoma tissues that invaded the stroma. c-Ets1 expression was associated significantly with histologic grade (P < 0.005), the presence of invasion to greater than one-half myometrium (P < 0.001), surgical stage (P < 0.005), and vascular involvement (P = 0.009). CONCLUSIONS: The authors' results show that c-Ets1 expression in endometrial carcinoma correlates with the malignant potential of this tumor.

Endometrial Neoplasms↗
PubMed2000

Involvement of caspase 3-like protease in methylmercury-induced apoptosis of primary cultured rat cerebral microglia.

Methylmercury (MeHg) has been implicated to induce massive neurodegeneration by disruption of neuron-glia interactions besides a direct potent neurotoxicity. In the present study, we examined potential cytotoxic effects of MeHg on primary cultured rat microglia. Following treatment with a relatively low concentration (0.5 microM) of MeHg, microglia had induced cell death accompanied by DNA fragmentation and an activation of caspase-3-like protease. MeHg-induced microglial death was significantly suppressed by the caspase-3-like protease inhibitor benzyloxycarbonyl-Try-Val-Ala-Asp-fluoromethyl-ketone indicating the occurrence of caspase-3-like protease-executed apoptosis. The aspartic protease inhibitor pepstatin A had a partial but significant inhibitory effect on MeHg-induced microglial apoptosis. These results indicate that a relatively low concentration of MeHg predominantly induces caspase-3-like protease-executed apoptosis of microglia, while the endosomal/lysosomal system is also partially involved in the cell death pathway.

Animals↗
PubMed2000

Treatment with a metallic endovascular stent in a patient with iliac venous stenosis due to endometrial cancer.

There are few cases, to our knowledge, that report the successful treatment of iliac venous stenosis due to gynecologic malignancies with the use of self-expanding metallic endovascular stents. Our patient, who had right lower limb edema, had iliac lymph node metastases which caused iliac vein stenosis by direct invasion from endometrial cancer. The patient was not considered to be a good surgical candidate. A 10-mm diameter self-expanding metallic endovascular stent was placed in the external iliac vein. The patient's symptoms of right lower limb edema improved dramatically, and she was discharged at 3 weeks after stent placement. The patient had no further symptoms, with continued resolution of the right leg edema during the 10 months following stent placement, at which time she died from the primary disease. The treatment to this patient with a self-expanding metallic endovascular stent proved to be very efficacious and less stressful than direct venous reconstruction or femorofemoral venous bypass grafting. In addition, this procedure dramatically improved the patient's quality of life.

Aged↗
PubMed2000

Intraplacental choriocarcinoma with fetomaternal transfusion.

Intraplacental choriocarcinoma is very rare, and is usually found only after maternal and fetal metastatic disease is identified. The purpose of this case report is to review the incidence and findings of intraplacental choriocarcinoma. A term placenta was investigated because the newborn was born with severe anemia (Hb 3.0 g/dL). A 2 cm nodule was noted on the surface of the amniotic membrane and grossly resembled an infarction. The tumor was examined microscopically with immunohistochemical staining for the alpha- and beta-human chorionic gonadotropin (alpha-hCG, beta-hCG) subunits, human placental lactogen (hPL) and Ki-67. Microscopically, the tumor consisted of necrotic areas with proliferation of atypical trophoblastic cells and destruction of the villi and capillaries. The cells were positive for the alpha-hCG, beta-hCG subunits, hPL and Ki-67, consistent with intraplacental choriocarcinoma. The mother and newborn were investigated for the presence of metastatic disease. Computed tomography scans and magnetic resonance imaging of the mother and infant were negative for metastatic disease. Choriocarcinoma, limited only to the placenta with no evidence of metastatic disease is very rare. Primary intraplacental choriocarcinoma may frequently be overlooked or missed, and choriocarcinoma may possibly arise in the placenta more often than in retained or persistent trophoblast following pregnancy.

Adult↗