Biomedical subjects

M Takeda

Publications and source records attributed to M Takeda.

At least 289 records · Page 16Linked to original sources

PubMed1998

Activation of protein phosphatase 2A by cAMP-dependent protein kinase-catalyzed phosphorylation of the 74-kDa B'' (delta) regulatory subunit in vitro and identification of the phosphorylation sites.

Human erythrocyte protein phosphatase 2A, which comprises a 34-kDa catalytic C subunit, a 63-kDa regulatory A subunit and a 74-kDa regulatory B'' (delta) subunit, was phosphorylated at serine residues of B'' in vitro by cAMP-dependent protein kinase (A-kinase). In the presence and absence of 0.5 microM okadaic acid (OA), A-kinase gave maximal incorporation of 1.7 and 1.0 mol of phosphate per mol of B'', respectively. The Km value of A-kinase for CAB'' was 0.17 +/- 0.01 microM in the presence of OA. The major in vitro phosphorylation sites of B'' were identified as Ser-60, -75 and -573 in the presence of OA, and Ser-75 and -573 in the absence of OA. Phosphorylation of B'' did not dissociate B'' from CA, and stimulated the molecular activity of CAB'' toward phosphorylated H1 and H2B histones, 3.8- and 1.4-fold, respectively, but not toward phosphorylase a.

Animals↗

PubMed1998

Factors affecting mandibular complications in low dose rate brachytherapy for oral tongue carcinoma with special reference to spacer.

PURPOSE: To evaluate the efficacy of a spacer in the prevention of mandibular complications in low dose rate (LDR) brachytherapy (BRT) for oral tongue carcinoma. METHODS AND MATERIALS: A retrospective analysis was conducted using 103 patients with T1 or T2 tongue carcinoma treated by a single plane implantation of iridium (192Ir) pins between 1979-1994. Of these patients, 60 were treated by BRT alone, and the rest were combined with external irradiation (Ext) and/or chemotherapy (CHT). Forty-eight and 55 patients were given BRT with and without a spacer, respectively. Spacers were individually made of acrylic resin according to a prosthetic technique so as to obtain the thickness of 7-10 mm at the lingual part of the implanted side. Variables, including a spacer, which may be associated with the development of osteoradionecrosis (ORN) of the mandible, were analyzed by the Cox proportional hazards regression analysis. RESULTS: Our spacer reduced about 50% of the absorbed dose at the lingual side surface of the lower gingiva (LSG) to that in the absence of a spacer. Absolute incidence of ORN was 2.1% (1 of 48) and 40.0% (22 of 55), with and without a spacer, respectively, and the difference was statistically significant by univariate analysis (p = 0.0004). It was revealed by the Cox analysis that the spacer (p = 0.0247), combined CHT (p = 0.0295), and combined Ext (p = 0.0279) were significant independent factors associated with the development of ORN. The spacer was shown to be a significant factor by univariate analysis (p = 0.0037), but not by multivariate analysis when analysis was restricted to the patients who did not receive CHT. The absorbed dose, dose rate, and biological effective dose (BED) reflecting early or late response were estimated at the LSG, and prognosticators associated with the incidence of ORN were also determined by the Cox analysis. Particularly, BED for late response by BRT, the total absorbed dose, and any BED by Ext plus BRT were highly significant factors in the whole population. Essentially similar results were obtained in the patients without receiving CHT. CONCLUSIONS: It was clarified that our spacer effectively prevents mandibular complications in LDR BRT by 192Ir for oral tongue carcinoma. Furthermore, introduction of a spacer provided novel information concerning the development of ORN, where BED particularly for late response given by BRT, the total absorbed dose, and any BED by Ext plus BRT could be good prognostic factors only when estimated at the LSG.

Adult↗

PubMed1998

Comparison of the structural characteristics of chromosome VI in Saccharomyces sensu stricto: the divergence, species-dependent features and uniqueness of saké yeasts.

Previous studies have revealed that chromosome VI of saké yeasts is much larger than that of the other strains of Saccharomyces cerevisiae. Southern analysis using segments of chromosome VI of a laboratory strain as probes suggested that the nucleotide sequence of a major portion of this chromosome is conserved, but considerable diversity was found in the distal parts in the other strains. Physical maps also indicated that differences in length of chromosome VI were mainly due to differences in its ends. NotI was found to generate 9 kb and/or 16 kb fragments from the left telomere of chromosome VI in most saké yeasts, but no fragment in the case of AB972. SfiI produced one or two 30-50 kb fragments from the right end of this chromosome in all saké yeasts tested, but produced a 20 kb fragment in the case of AB972. All S. cerevisiae strains not employed in saké brewing were the same as AB972 in these respects. S. paradoxus had one NotI site in chromosome VI, while S. bayanus had two, one of which is possibly common to both species. The SfiI site mentioned above was present in chromosome VI of all species, while that of S. bayanus and S. paradoxus each had a second site distinct from the other. Chromosome VI of S. pastorianus was not distinguishable from that of S. bayanus.

Blotting, Southern↗

PubMed1998

Bulbectomy of neonatal mice induces migration of basal cells from the olfactory epithelium.

Bulbectomy of neonatal mice induced cell migration from the olfactory epithelium in the nasal septum. We examined cell types of migrating clusters by immunohistochemistry using anti-keratin and anti-BrdU antibodies, and by electron microscopy. At 1-2 days after unilateral bulbectomy of P1 mice, cells migrated from the olfactory epithelium to the lamina propria of the septal olfactory mucosa. Horizontal basal cells that reacted specifically with anti-keratin antibody, and globose basal cells characterized by a round shape and poor content of organellae in their cytoplasm, were contained in the cluster. At 1 week, migrated clusters that contained keratin-positive horizontal basal cells were observed in both the lamina propria and olfactory bulb on the unoperated side. At 1 month, not only basal cells but also olfactory cells and presumed supporting cells were involved in the clusters in the lamina propria and olfactory bulb, suggesting that migrated cells do not transform to other phenotypes.

Animals↗

PubMed1998

Variable Bcl-2 phenotype in benign and malignant lesions of urothelium.

We examined Bcl-2, Bax and p53 expression in transitional epithelium, benign lesions derived from transitional epithelium (Brunn's nests and inverted papillomas) and transitional cell cancer (TCC) of the upper urinary tract and urinary bladder using immunostaining of cryostat sections. We also performed Western blot analysis of normal urothelium and TCCs for Bcl-2 and p53. Immunohistochemical staining showed that Bcl-2 was expressed only on basal layer cells, whereas Bax expression was restricted to superficial layers in normal transitional epithelium. Benign lesions of the urinary bladder (Brunn's nests and inverted papillomas) showed strong immunoreactivity to Bcl-2. Taken together, 16 (17%) TCCs were positive for Bcl-2, 62 (64.6%) TCCs were positive for Bax and 28 (29%) TCCs were positive for p53. The expression of Bcl-2 on TCC had a statistical correlation with tumor stage, histopathologic grade and p53 protein accumulation. The results suggest that although Bcl-2 overexpression is detected in normal urothelium and benign lesions of the urinary bladder, it might also contribute to the high grade tumor malignancy of TCC.

Adult↗

PubMed1998

A novel method of assessing carcinoma cell proliferation by biophoton emission.

Changes in the emission intensities of ultraweak biophoton emission during the cell proliferation of human carcinoma cell culture (TE9 cell line) were detected using a highly sensitive and low noise measurement apparatus coupled with a flow culture system. In the sampling period of 93 h, the biophoton emission intensity from the culture followed a similar course as that of the growth curve. Spectral analysis of the biophoton emission from the cell culture demonstrated a significant peak at around 530 nm. Our results suggest that the emission intensity mainly depends on the cell population and that this noninvasive technique has a potential role in cancer diagnosis.

Carcinoma↗

PubMed1998

Domain- and site-specific phosphorylation of bovine NF-L by Rho-associated kinase.

Rho-associated kinase (Rho-kinase), the putative target of the small GTP-binding protein Rho, phosphorylated neurofilament protein (NF-L) in vitro with approximately 1 mole phosphate per mole NF-L. Phosphorylated NF-L no longer formed the 10 nm filaments, and NF-L filaments were phosphorylated with a result of nearly complete disassembly. NF-L phosphorylated by Rho-kinase was digested with trypsin, and digested fragments were assigned by MALDI/TOF. Unique phosphorylation sites were found at Ser-26 and Ser-57 in the head domain of NF-L. These results indicate that domain- and site-specific phosphorylation by Rho-kinase may regulate the assembly-disassembly of NF-L filaments.

Amino Acid Sequence↗

PubMed1998

Aberrant muscle activation in patients after resection of non-primary motor areas: demonstration by surface electromyography.

Two patients presented with a tumor involving mainly the supplementary motor area or the premotor cortex. Shortly after tumor resection, each developed transient impairment of voluntary movements. An electromyogram, with the skin electrodes placed over the muscles of the upper arms and forearms, demonstrated aberrant ipsilateral, contralateral or bilateral muscle activation during unilateral motor tasks in both patients. The bilateral activation was more prominent in the patient who had an intact dominant hemisphere. The present study suggests for the first time the importance of non-primary motor areas of the human brain in activating the proper set of muscles on the proper side of the body.

Adult↗

PubMed1998

Alzheimer-associated presenilin-1 gene is induced in gerbil hippocampus after transient ischemia.

To investigate the biological roles of the presenilin-1 (PS-1) gene after neuronal injury, the changes of PS-1 mRNA expression in the gerbil hippocampus after transient ischemia were examined. From 1 day to 3 day-reperfusion after 5 min-ischemia, PS-1 mRNA was induced in the hippocampus compared with the sham-operated control. The cells which induced the PS-1 genes were neurons of CA3 and dentate gyrus, the region relatively resistant to ischemic stress. These findings suggest that the induction of PS-1 genes may be associated with some responses of neurons damaged by transient ischemia.

Alzheimer Disease↗

PubMed1998

Involvement of macromolecule synthesis, endonuclease activation and c-fos expression in cisplatin-induced apoptosis of mouse proximal tubule cells.

We have previously demonstrated that cisplatin-induced nephrotoxicity is associated with the induction of apoptosis using mouse renal cells derived from the terminal proximal tubule (S3) which is the major target site of cisplatin-induced injury. The purpose of this study was to elucidate the intracellular mechanisms leading to the cisplatin-induced apoptosis of S3 cells. Actinomycin D (an inhibitor of RNA synthesis), cycloheximide (an inhibitor of protein synthesis) and aurintricarboxylic acid (an endonuclease inhibitor) reduced the extent of DNA fragmentation, a biochemical parameter of apoptosis, in cisplatin-treated S3 cells. Furthermore, cisplatin-induced apoptosis of S3 cells was accompanied by an increase in the level of c-fos mRNA expression, which is inhibited by pretreatment of the cells with actinomycin D, but not with cycloheximide or aurintricarboxylic acid. In contrast, outer medullary collecting duct cells treated with cisplatin exhibited morphological changes characteristic of apoptosis and an increase in the level of c-fos mRNA expression, but no increase in the extent of DNA fragmentation. In conclusion, the synthesis of macromolecules such as RNA and protein, endonuclease activation and c-fos expression appear to be involved in the intracellular pathways leading to the induction of apoptosis in cisplatin-treated S3 cells. In addition, the response to cisplatin may be different in different cells.

Animals↗

PubMed1998

Gain-of-function mutations of c-kit in human gastrointestinal stromal tumors.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the human digestive tract, but their molecular etiology and cellular origin are unknown. Sequencing of c-kit complementary DNA, which encodes a proto-oncogenic receptor tyrosine kinase (KIT), from five GISTs revealed mutations in the region between the transmembrane and tyrosine kinase domains. All of the corresponding mutant KIT proteins were constitutively activated without the KIT ligand, stem cell factor (SCF). Stable transfection of the mutant c-kit complementary DNAs induced malignant transformation of Ba/F3 murine lymphoid cells, suggesting that the mutations contribute to tumor development. GISTs may originate from the interstitial cells of Cajal (ICCs) because the development of ICCs is dependent on the SCF-KIT interaction and because, like GISTs, these cells express both KIT and CD34.

Amino Acid Sequence↗

PubMed1998

Effects of NMDA and non-NMDA receptor antagonists on the medullary inspiratory neuronal activity during spontaneous augmented breaths in anesthetized rats.

To elucidate whether there is a difference between the effects of iontophoretically applied N-methyl-D-aspartate (NMDA) and non-NMDA receptor antagonists on the activity of inspiratory neurons during spontaneous augmented breaths, extracellular single unit recording of inspiratory neurons (I-augmenting, I-decrementing and I-other) was performed in pentobarbital anesthetized rats. The spontaneous augmented breath was divided into two different phases; the first phase (phase I) resembled a normal inspiration, but the second phase (phase II) consisted of a marked increase in diaphragm electromyogram activity. The mean firing frequency of I-aug type neurons was significantly decreased after 50 nA application of both D-2-amino-5-phosphonopentanoic acid (AP-5) (NMDA receptor antagonist) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) (non-NMDA receptor antagonist). The mean firing frequency of both I-dec and I-other neurons was significantly decreased by both AP-5 and CNQX applications (70 nA). After AP-5 application, relative changes in the discharge rates during inspiratory phases I and II of spontaneous augmented breaths were significantly suppressed in all types of neurons, but CNQX application had no significant effect on the response changes during phase II. In all cell types of neurons, a significant difference between the iontophoretic AP-5 and CNQX applications in the relative mean firing rate was observed. These results suggested that activation of the NMDA receptor-induced neurotransmission can modify the discharge rate of medullary inspiratory neurons, irrespective of the cell types, during the inspiratory phase II of spontaneous augmented breaths, but that non-NMDA receptor blockade may not significantly influence their discharge rate.

2-Amino-5-phosphonovalerate↗

PubMed1998

Involvement of H2O2 production in cisplatin-induced nephrotoxicity.

The purpose of this study was to elucidate the involvement of H2O2 production in cisplatin-induced nephrotoxicity. The S3 cells were more sensitive than OMCT cells in cell viability and H2O2 production during cisplatin treatment. The cytotoxicity and H2O2 production induced by cisplatin were terminated by treatment with catalase. In conclusion, we emphasize the importance of the hydroxy radical in cisplatin nephrotoxicity.

Animals↗

PubMed1998

Enhanced expression in seminoma of human zinc finger genes located on chromosome 19.

Six Krüppel-type zinc finger (ZF) genes were cloned from a seminoma cDNA library. One, ZFS-1, showed high sequence homology to the ZNF91 KRAB (Krüppel-associated box) ZF gene family and also the same chromosomal assignment. Interestingly, Northern blot analyses using ZFS-1 and ZNF91 revealed that multiple ZF genes on chromosome 19 were predominantly expressed in seminomas. In addition, the testis and the seminoma showed specific expression of 2.3 kb transcript. Our results suggest that ZF genes on chromosome 19 may be implicated in the development and/or growth of seminomas.

Amino Acid Sequence↗

PubMed1998

Urinary levels of monocyte chemoattractant protein (MCP)-1 and disease activity in patients with IgA nephropathy.

Using a quantitative sandwich ELISA, we studied 17 patients with IgA nephropathy to determine if levels of urinary monocyte chemoattractant protein-1 (MCP-1) might reflect the disease activity. The levels of urinary MCP-1 in patients with the advanced stage were significantly higher than those in patients with the mild stage of the disease, or in healthy controls. The results showed a significant correlation between the levels of urinary MCP-1 and the disease activity, i.e., levels of urinary casts and urinary protein. It was thus suggested that the measurement of urinary MCP-1 is useful in evaluating the degree of renal injuries and/or prognosis in patients with IgA nephropathy.

Adult↗

PubMed1998

Expression of E- and P-cadherin during tooth morphogenesis and cytodifferentiation of ameloblasts.

Cell-cell adhesion is fundamental in morphogenesis and is known to be mediated by several groups of cell adhesion molecules. Cadherins are a group of such molecules involved in the Ca2+-dependent cell-cell adhesion mechanism and are found in most kinds of tissue. In this study using indirect immunofluorescence microscopy, we analyzed the distribution of two kinds of cadherins, E- and P-cadherin, in developing tooth germs. In the molar tooth germs at the early bud stage, marginal cells of the epithelial tooth bud expressed both E- and P-cadherin, whereas central cells expressed only E-cadherin. At the cap stage, in addition to the cells of the inner and outer enamel epithelium, which outline the enamal organ, cells of the enamel knot, which is thought to control tooth morphogenesis, strongly expressed P-cadherin. The expression of P-cadherin was prominent in the inner enamel epithelium during the early to mid bell stage, and was also evident in the non-dividing cell masses at future cusp tips, which are the so-called secondary enamel knots. In the tooth germ at the late bell stage when the cells of the inner enamel epithelium began to polarize to differentiate into ameloblasts, the polarizing ameloblasts lost P-cadherin and strongly expressed E-cadherin. However, E-cadherin was also lost from polarized ameloblasts at later stages. The stratum intermedium and the stellate reticulum were E-cadherin positive from the bell stage onward even at the stages when the ameloblasts became E-cadherin negative again. These results suggest that the differential expression of E- and P-cadherin during morphogenetic stages plays a role in the regulation of tooth morphogenesis, whereas alteration of E-cadherin expression during later stages of tooth development is related to differentiation and function of the ameloblasts and other cells supporting amelogenesis.

Ameloblasts↗

PubMed1998

Colchicine-induced cell death and proliferation in the olfactory epithelium and vomeronasal organ of the mouse.

The cytotoxic agent colchicine induced apoptotic cell death and subsequent regeneration in the mouse olfactory epithelium and vomeronasal organ. The TUNEL method revealed the presence of many apoptotic bodies in the middle to basal region of the septal olfactory epithelium and vomeronasal organ near the boundary of the respiratory epithelium at 1 day after a single i.p. injection of colchicine (4 mg/kg b.w.). In some regions of the third and the fourth nasal turbinates, massive apoptosis was observed in the olfactory epithelium. Electron micrographs of the septum showed that immature olfactory cells and globose basal cells were killed by the colchicine and had been phagocytized by the supporting cells and macrophages. In the vomeronasal organ, immature sensory cells and precursors died in response to the colchicine. In response to cell death, active proliferation of precursor cells (globose basal cells) and subsequent regeneration of olfactory cells occurred in the olfactory epithelium and vomeronasal organ. Incorporation of the mitotic tracer BrdU by precursor cells reached its peak at 4 days after colchicine treatment in the vomeronasal organ, and at 6 to 7 days in the olfactory epithelium; however, in some regions in the third and the fourth nasal turbinates, where many olfactory cells and globose basal cells had died by colchicine effect, the regeneration did not occur even in 1 month, forming the epithelium of only supporting cells and horizontal basal cells. In the next month, these regions became normal olfactory epithelium. This suggests that the globose basal cells in the surrounding normal olfactory epithelium might invade these regions to give rise to the olfactory cells.

Animals↗

PubMed1998

A surgical technique for a vertebral column autograft using the intervertebral disc for cervical disc disease.

We describe a surgical technique for a vertebral column autograft using the intervertebral disc for cervical disc disease for patients whose major problem is not spinal instability. Of a total of 41 patients with cervical disc disease suffering from cervical spondylotic radiculomyelopathy, 33 patients were operated on at one level and 8 patients were operated on at two levels. Postoperative X-ray film showed some movement at the "operated" disc level in all patients (average postoperative follow-up period was 43 months, range two years to 5 years). A significant decrease in motion in the extension position was observed postoperatively (p < 0.0001), but no significant difference was observed between the preoperative motion and the postoperative motion in the flexion position. Anterior angulation was found in two (5%) of the 41 patients. This surgical procedure has two major advantages: 1) no complications related to the iliac donor site, allowing early patient mobilization; 2) the extensive posterior spur can be removed safely and easily under a wide operative field. We believe that this surgical procedure is suitable for preserving the mobility of the spine and may avoid stress concentration at adjacent levels of the "operated" disc. However, in patients whose major problem is spinal instability, anterior cervical fusion should be performed.

Adult↗