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N Takai

Publications and source records attributed to N Takai.

At least 37 records · Page 2Linked to original sources
PubMed2000

Polo-like kinase expression in normal human endometrium during the menstrual cycle.

The enzyme, polo-like kinase (PLK), is a mammalian serine/threonine kinase involved in cell cycle regulation. A great deal of evidence regarding the role of PLK in the cell cycle has been obtained through studies of cultured cells, though little is known about its function or even expression in vivo. The endometrium undergoes rapid proliferation and differentiation under ovarian steroid hormone control during the 28-day cycle. Thus, normal endometrium provides an excellent model in which to study the hormone dependency of PLK expression. In the present study, we examined the features of PLK expression in 20 samples of normal human endometrium during the menstrual cycle. The expression of Ki-67 and proliferating cell nuclear antigen (PCNA) were also examined as markers of proliferation. Immunohistochemical studies showed that PLK staining was detected in the basement membrane of many endometrial glands, stromal cells, and some endothelial cells. The number of PLK-positive endometrial gland cells was significantly higher in the late proliferative phase (19.16% +/- 4.98%) and the early secretory phase (19.28% +/- 4.99%) than in the early proliferative phase (2.60% +/- 2.33%) or the late secretory phase (5.76% +/- 2.16%) (P<0.0001). PLK expression seemed to be correlated with the expression of Ki-67 and PCNA in many endometrial glands and stromal cells particularly in the late proliferative phase, reflecting a role of PLK in cellular proliferation. Nevertheless, in the early secretory phase, at which point the expression of Ki-67 and PCNA decreased in endometrial glands, PLK was strongly expressed. This finding suggests that PLK may have some post-mitotic functions in certain specialized cell types. Although the highest expression of PLK was observed in the late proliferative and the early secretory phases, the expression drastically decreased in the late secretory phase. These findings, taken together, indicate that the expression of PLK in normal endometrium fluctuates over the course of the menstrual cycle, suggesting in turn that PLK is associated with hormone-dependent cellular proliferation and that hormone functions may be involved in its regulation.

Adult↗
PubMed1999

Localization of neuronal-constitutive nitric oxide synthase and secretory regulation by nitric oxide in the rat submandibular and sublingual glands.

The distribution of neuronal-constitutive nitric oxide synthase (ncNOs)-positive nerve fibres was compared immunohistochemically, and the effect of NOs inhibitor and NO scavenger on the secretory response was compared functionally, in the two glands. Numerous ncNOs-positive fibres were distributed around acini in the submandibular gland but scarcely any around acini in the sublingual gland. Within the submandibular ganglion (parasympathetic), the nerve-cell bodies were strongly positive. Within the superior cervical ganglion (sympathetic), the nerve-cell bodies were negative, although some positive nerve fibres were observed. The secretory responses to the electrical stimulation of the chorda were significantly reduced by the NOs inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME, 10(-9)-10(-3) M) in a dose-dependent manner. The NO scavenger, 2-(4-carboxyphenyl)4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (carboxy-PTIO) also reduced the chorda-evoked secretion (10(-9)-10(-6) M). The submandibular secretions evoked by stimulation of the superior cervical ganglion were not affected by L-NAME or carboxy-PTIO. In the sublingual gland, neither L-NAME nor carboxy-PTIO affected chorda-evoked salivary secretion. The histochemical and functional results both suggest that NO plays an excitatory role in the regulation of parasympathetic nerve-induced salivary secretion in the rat submandibular gland, but not in the sublingual gland.

Animals↗
PubMed1999

The simple indicator for revascularization of acute middle cerebral artery occlusion using angiogram and ultra-early embolectomy.

BACKGROUND: The purpose of the study was: (1) to find a clinical indicator for revascularization of acute middle cerebral artery (MCA) occlusion using angiograms of 100 patients examined immediately after onset and treated medically and (2) to investigate 10 ultra-early MCA embolectomies. METHODS: Quantity of collateral circulation, based on time required for conduction of contrast media to the insular portion of the MCA from the anterior cerebral artery, MCA conduction time (MCT) was graded as: Grade 1: In the arterial phase, there was conduction not only to the insular portion of the MCA but also to proximal M2; Grade 2: Conduction to the insular portion was present in late arterial phase; Grade 3: Conduction was present in capillary phase; Grade 4: Conduction was present in venous phase; Grade 5: No conduction was seen. The results of embolectomy are discussed. RESULTS: MCT can predict the extent of resultant low-density area on computed tomographic scan. For Grades 3, 4, or 5, embolectomy could be considered superior to medical treatment, if the low-density area was localized in the basal ganglia or centrum semiovale after surgery. Consequently, embolectomy was effective in four cases recanalized within 6 hours of onset. Except for one Grade 5 case, the remaining nine cases showed neither lethal hemorrhagic infarction nor brain edema. Overall outcome was significantly better than cases treated medically (p < 0.05), but some cases did not recover from hemiparesis due to infarcts in the area of the lenticulostriate arteries. CONCLUSIONS: MCT helps to predict the applicability of revascularization of acute MCA occlusion. Efficacy of embolectomy depends on revascularization within 6 hours of onset. Even after complete MCA flow restoration, infarcts in the area of the lenticulostriate arteries cannot always be prevented.

Acute Disease↗
PubMed1999

Expression of N-methyl-D-aspartate receptor-dependent long-term potentiation in the neostriatal neurons in an in vitro slice after ethanol withdrawal of the rat.

To examine changes in corticostriatal synaptic transmission in rats with ethanol withdrawal syndrome, intracellular and extracellular responses to subcortical white matter stimulation were recorded in neostriatal slice preparations. The resting membrane potential, input resistance and depolarizing postsynaptic potentials to single cortical white matter stimulation were similar in the neostriatum of naive and ethanol withdrawal rats. Repetitive stimulation of the white matter induced more pronounced N-methyl-D-aspartate receptor-mediated postsynaptic potentials in ethanol withdrawal than naive rat neostriatum. In intracellular recording, tetanic stimulation (50 Hz, 20 s) induced more pronounced post-tetanic potentiation of depolarizing postsynaptic potentials in the neostriatum of ethanol withdrawal than naive rats. However, in extracellular recording, tetanic stimulation induced smaller post-tetanic depression of population spikes in the neostriatum of ethanol withdrawal than naive rats. Tetanic stimulation of the subcortical white matter induced long-term potentiation of postsynaptic potentials and population spikes in the ethanol withdrawal rat neostriatum, while long-term depression was evoked in the naive rat neostriatum. The induction of long-term potentiation was blocked by D-2-amino-5-phosphonovaleric acid or 7-chlorokynurenic acid, N-methyl-D-aspartate receptor antagonists, but not by (RS)-methyl-4-carboxyphenyl-glycine, a metabotropic glutamate receptor antagonist. Dopamine also significantly depressed the induction of long-term potentiation in ethanol withdrawal rat neostriatum and this depressant effect was antagonized by the D2 antagonist L-sulpiride but not by the D1 antagonist SCH23390. These results indicate that the N-methyl-D-aspartate component of the corticostriatal glutamatergic responses, which might be necessary for induction of long-term potentiation, was enhanced in ethanol withdrawal rats. The depression of long-term potentiation induction by activation of D2 receptor suggests that corticostriatal N-methyl-D-aspartate response or intracellular mechanisms involving in the induction of the long-term potentiation can be suppressed by D2 activation and that the D2 effects are inhibited in the neostriatum of ethanol withdrawal rats.

Animals↗
PubMed1999

Expression of polo-like kinase (PLK) in the mouse placenta and ovary.

The polo-like kinase (PLK) is a mammalian serine/threonine kinase involved in cell cycle regulation. Much evidence for the role of PLK in the cell cycle has come from studies of cultured cells; however, little is known about its function or even expression in vivo. The present study examined the features of PLK expression in the mouse placenta and ovary. Immunohistochemical studies showed that PLK is highly expressed in the basement membrane of the endometrial gland, in some endothelial cells, in endometrium after embryo implantation, in trophoblastic tissue invading the decidua, in the ovarian stroma and in some lutein bodies. In contrast, PLK was not detectable by immunohistochemistry in endometrial stroma before decidualization, in decidua, in trophoblastic tissue not invading the decidua or in ovarian follicles. PLK expression seemed to be correlated with the expression of proliferation cellular nuclear antigen (PCNA) in many placental and ovarian cells, reflecting a role in cellular proliferation. Nevertheless, in ovarian stroma and lutein bodies where PCNA was not expressed, PLK was strongly expressed. This finding indicates that PLK may have some post mitotic functions in certain specialized cell types.

Amino Acid Sequence↗
PubMed1999

Remission of idiopathic hypoparathyroidism during lactation: a case report.

A 35-year-old woman with idiopathic hypoparathyroidism achieved a spontaneous remission during lactation even though 1-alpha-hydroxyvitamin D3 therapy was discontinued after delivery. Urinary excretion of cyclic adenosine 3',5'-monophosphate and phosphate was significantly increased during lactation, probably in response to the increased levels of circulating parathyroid hormone-related protein derived from the breast tissue.

Adult↗
PubMed1999

Endometrioid adenocarcinoma arising from adenomyosis.

In spite of many references to carcinoma arising from endometriosis at extrauterine sites, there are few documented cases of carcinoma developing in association with adenomyosis. We present 2 rare cases of adenocarcinoma arising from adenomyosis. The relationship between prior frequent estrogen use and carcinogenesis and the possible effects of chemotherapy and radiation therapy are reviewed.

Adenocarcinoma↗
PubMed1999

Immunohistochemical localization of polo like kinase in early human placenta.

Polo like kinase (PLK) is the kinase that was first cloned by us from the cDNA library of human placenta. It belongs to the serine/threonine kinase family and plays a very important role in cell proliferation. In this study, the localization of PLK in early human placenta in vivo was investigated. Immunostaining revealed PLK protein in syncytiotrophoblastic cells and extravillous trophoblastic cells; however proliferating cell nuclear antigen was not. It is known that cytotrophoblastic cells proliferate highly in early human placental villi; however, PLK was not detected in those cells. These results suggest that PLK plays a different role in syncytiotrophoblastic cells than it does in other proliferating cells.

Cell Cycle Proteins↗
PubMed1998

Hyperexcitability of amygdala neurons of senescence-accelerated mouse revealed by electrical and optical recordings in an in vitro slice preparation.

In the amygdala (AMG) slices obtained from both the young (4-7 months old) and aged (17-20 months old) groups of Senescence-Accelerated Mouse (SAM) P10, spontaneous bursts were recorded in the medial, central and basolateral nuclei. The spontaneous bursts were also observed in the slices from the young group of SAMR1, whereas the mean frequency was significantly lower than that from the young group of SAMP10. The spontaneous burst was barely detectable in slices from the aged group of SAMR1 during perfusing with the standard solution, while bicuculline methiodide (10 microM), a GABAA receptor antagonist, or Mg2+-free solution induced a similar bursting activity observed in the young group. The burst response was also evoked in the medial, central and basolateral AMG following stimulation of the stria terminalis (ST). Both spontaneous and evoked bursts were completely suppressed by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 4 microM), an alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)/kainate receptor antagonist, but not by (+)-5-methyl-10, 11-dihydro-5H-dibenzo-[a,d]-cyclohepten-5,10-imine hydrogen maleate (MK-801, 30 microM), an N-methyl-d-aspartate receptor antagonist. The hyperexcitability of the AMG neurons was further substantiated by optical recordings. Following stimulation of the ST, the optical signals reflected postsynaptic responses spread into the medial and central AMG areas at 2-5 ms and faded out at 20-30 ms after stimulation. The intensity of the optical signal recorded in the slice from the young SAMP10 was significantly higher than that from SAMR1 or ddY mice. These observations indicate that bursts mediated by AMPA/kainate receptors were transiently generated in the AMG of SAMR1 at the young age, while the bursts with higher frequency were continuously generated in the AMG of SAMP10. The chronic neuronal hyperactivity in the AMG may be partially responsible for the age-related deterioration of memory and learning abilities observed in SAMP10.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1998

Involvement of caspase-like proteinases in apoptosis of neuronal PC12 cells and primary cultured microglia induced by 6-hydroxydopamine.

Activation of proteolytic enzymes, including the caspase family of proteinases, is a feature characteristic of the apoptotic program. In the present study, we examined a potential role of intracellular proteinases in the death of neuronal PC12 and primary cultured rat microglial cells induced by 6-hydroxydopamine (6-OHDA). In both neuronal PC12 and microglial cells, 6-OHDA (10-200 microM) induced apoptosis in a dose-dependent manner as judged by the DNA break. The 6-OHDA was ineffective in Bcl-2-overexpressing neuronal PC12 cells. Pretreatment of these cells with two caspase inhibitors, acetyl-Try-Val-Ala-Asp-aldehyde and acetyl-Asp-Glu-Val-Asp-aldehyde, prevented the 6-OHDA-induced apoptosis. Pepstatin A and leupeptin, potent inhibitors of aspartic and cysteine proteinases, respectively, partly inhibited the apoptosis of microglia but not neuronal PC12 cells. In contrast, GBR12935, a dopamine uptake inhibitor, significantly inhibited the apoptotic death of neuronal PC12 cells but not microglia. These results suggest that mechanisms by which 6-OHDA induces apoptosis in these two cell types are distinct; 6-OHDA incorporated into neuronal PC12 cells and its metabolites may activate the caspase-like enzymes, whereas oxidative metabolites of the agent produced extracellularly may activate the caspase and the endosomal/lysosomal proteolytic systems in microglia.

Animals↗
PubMed1998

An increase in [3H]QNB binding by proton-beam irradiation in intact rat brain: an apparent positive cooperativity of binding.

After focal irradiation of rat brains with a beam of proton (dose, 30 Gy), [3H]quinuclidinyl benzilate (QNB) binding, both in vitro and in vivo, was measured, using either autoradiographic or tissue-dissection methods. No changes in in vitro [3H]QNB binding were seen in autoradiograms of brain slices from irradiated rat. The irradiated side of the brain showed a significant increase in [3H]QNB binding in vivo in the striatum and cerebral cortex 24 h after irradiation. This increase in binding was transient, and had almost disappeared 2 weeks after irradiation. These results indicate that early changes in receptor function as a results of radiation damage are only detected in in-vivo conditions. In the striatum of the intact rat brain, an apparent positive cooperativity of binding was observed, which was more pronounced on the irradiated side.

Animals↗
PubMed1998

Ruptured distal anterior choroidal artery aneurysm presenting with casting intraventricular haemorrhage.

This report describes a rare case of a distal anterior choroidal artery aneurysm which developed intraventricular haemorrhage without subarachnoid haemorrhage as shown on computerized tomographic (CT) scan. A 69-year-old hypertensive man suddenly became unconscious. An emergency CT scan showed a severe intraventricular haemorrhage and a small round low-dense lesion within the haematoma at the right trigone. The haematoma with obstructive hydrocephalus made the lateral ventricles larger on the right than on the left. CT scan could not detect any subarachnoid haemorrhage. Right interal carotid angiography revealed a saccular aneurysm at the plexal point of the right anterior choroidal artery. We approached the aneurysm and the small round lesion through the trigone via a right temporo-occipital corticotomy. We could clip the aneurysmal neck and remove the intraventricular haematoma and the papillary cystic mass (corresponding to the small round lesion on CT scan) totally in one sitting. Histological examination revealed the aneurysm to be a true one and the papillary cystic mass to be a choroid plexus cyst.

Aged↗
PubMed1998

Interleukin-1beta and interleukin-8 in cervicovaginal fluid during pregnancy.

OBJECTIVE: We investigated the usefulness of cervicovaginal interleukin-1beta and interleukin-8 levels during pregnancy as markers of preterm and term parturition. STUDY DESIGN: Cervicovaginal fluids were obtained from 119 pregnant women at 24 to 41 weeks' gestation. Cytokine concentrations were measured by enzyme-linked immunoassay. RESULTS: Interleukin-1beta and interleukin-8 concentrations in cervicovaginal fluids obtained from women not in labor increased exponentially as gestational age increased. Interleukin-1beta and interleukin-8 concentrations were significantly correlated. These cytokine concentrations were significantly higher in patients in preterm labor than in patients at preterm not in labor and were significantly higher in women at term in labor than in women at term not in labor. These cytokine levels were significantly correlated with the degree of cervical dilation and tocolytic index. CONCLUSIONS: These findings suggest that cervicovaginal interleukin-1beta and interleukin-8 contribute to term and preterm parturition. Measurement of cervicovaginal concentrations of these cytokines may be clinically useful in patients with threatened premature delivery.

Adult↗
PubMed1998

MaMi, a human endometrial stromal sarcoma cell line that constitutively produces interleukin-6, interleukin-8, and monocyte chemoattractant protein-1.

BACKGROUND: Uterine endometrial stromal sarcoma is a rare neoplasm with a morphology that closely resembles that of the proliferative endometrial stroma. To understand its pathologic characteristics, we established a novel cell line, MaMi, from a primary culture of an endometrial stromal sarcoma obtained from a 65-year-old Japanese woman. METHODS: We observed the morphology of MaMi cells and performed immunohistochemical analysis on the primary tumor and transplants in nude mice. Prolactin, insulin-like growth factor-binding protein-1, interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, E-selectin, vascular cell adhesion molecule-1, and fibronectin production in the culture medium of MaMi cells were also examined. RESULTS: MaMi cells were shown to exhibit a fibroblast-like morphology in vitro, and they adopted a more elongated appearance in response to 12-O-tetradecanoyl phorbol-13-acetate (TPA). On injection into nude mice, the cells gave rise to subcutaneous tumors. Immunohistologically, both the primary tumor and MaMi cell-induced tumors stained positively with antibodies to neuron-specific enolase or vimentin. MaMi cells constitutively produced IL-6, IL-8, and monocyte chemoattractant protein-1 in vitro. Interleukin-1beta, (100 pmol/L), tumor necrosis factor-alpha (1 nmol/L), and lipopolysaccharide (1 microg/mL) each increased the release of IL-6, IL-8, and monocyte chemoattractant protein-1 by MaMi cells. TPA (10 nmol/L) also stimulated the production of IL-6 and IL-8 by these cells, but inhibited that of monocyte chemoattractant protein-1. CONCLUSIONS: We demonstrated that MaMi cells closely resemble proliferative endometrial stromal cells not only morphologically, but also functionally. This cell line may prove valuable in understanding the role of cytokines produced by tumor cells in the pathogenesis of endometrial stromal sarcoma and may also be useful as an in vitro model of functioning endometrial stromal cells.

Aged↗
PubMed1997

Primary structure of rat CD14 and characteristics of rat CD14, cytokine, and NO synthase mRNA expression in mononuclear phagocyte system cells in response to LPS.

Rat CD14 cDNA clones were isolated. The predicted protein sequence exhibits 82, 61.6, and 64% identity with the mouse, rabbit, and human CD14, respectively. The levels of rat CD14 mRNA expression in resident peritoneal macrophages (PM), alveolar macrophages (AM), and peripheral blood monocytes (BM) were constitutively high, whereas that in Kupffer cells (KC) was low. On intravenous injection with lipopolysaccharide (LPS), the expression of rat CD14 mRNA in KC increased markedly, whereas the increases in PM, AM, and BM were mild. Similar features of expression of rat CD14 in these cells were observed after stimulation with LPS in vitro. The level of tumor necrosis factor alpha (TNF-alpha) mRNA expression in KC after stimulation with LPS in vivo was comparable to that in PM, AM, and BM, whereas that of TNF-alpha mRNA expression in KC and PM after stimulation with LPS in vitro was lower than that in AM and BM. Interleukin (IL)-1 beta and iNOS mRNA expressions in KC after stimulation with LPS in vivo and in vitro were low, whereas those in PM, AM, and BM were high. Little or no expression of IL-6 was observed in KC after stimulation with LPS in vivo and in vitro, whereas higher expression was observed in PM, AM, and BM than in KC.

Amino Acid Sequence↗
PubMed1997

Expression of vasoactive intestinal polypeptide receptor mRNA and secretory regulation by vasoactive intestinal polypeptide in rat submandibular and sublingual salivary glands.

Vasoactive intestinal polypeptide (VIP)-receptor mRNA was strongly expressed in the acinar cells in the submandibular gland but not in the sublingual gland. VIP-containing nerve fibres were richly distributed around acini in the submandibular gland but were rare around acini of the sublingual gland. In the submandibular gland, the chorda was stimulated at various frequencies (1-40 Hz) together with an infusion of (N-Ac-Tyr1, D-Phe2)-GRF(1-29)-NH2 (109 M), VIP antagonist, which reduced salivary flow from the submandibular gland only at high-frequency stimulation (> 20 Hz), and more markedly reduced the salivary protein concentration. When the chorda was continuously stimulated the antagonist reduced the salivary flow only during the initial 5 min. Exogenous VIP 10(-12) - 10(-8) M) infusion at the same time as chorda stimulation caused no increase in salivary flow, but the salivary protein concentration was increased in a dose-dependent manner. In the sublingual gland, neither VIP nor the VIP antagonist affected chorda-evoked salivary flow and protein concentration. Thus, endogenous VIP may play a part in the regulation of both fluid and protein secretion, especially of protein, evoked by chorda stimulation at high frequency in the submandibular gland. These phenomena occurred only in the initial phase of secretion. In the sublingual gland, it seems likely that VIP plays no part in the regulatory mechanism, at least with regard to salivary fluid secretion in the acinar cells.

Animals↗