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T Muramatsu

Publications and source records attributed to T Muramatsu.

At least 73 records · Page 4Linked to original sources
PubMed2001

Glypican-2 binds to midkine: the role of glypican-2 in neuronal cell adhesion and neurite outgrowth.

Cell-surface heparan sulfate proteoglycans participate in molecular events that regulate cell adhesion, migration, and proliferation. The present study was performed to elucidate whether glypican-2 plays a role in interactions of neurons with midkine (MK), a heparin-binding neuroregulatory factor. MK bound to heparan sulfate chains of glypican-2 in a manner similar to syndecan-3. Microbeads coated with MK or poly-L-lysine induced clustering of glypican-2 as well as syndecan-3. Substratum-bound MK or poly-L-lysine induced cell adhesion of N2a neuroblastoma cells, while only MK promoted neurite outgrowth of these cells. Ligation of cell-surface glypican-2 with MK or an antibody against epitope-tagged glypican-2 induced cell adhesion and promoted neurite outgrowth. These results verified that cell-surface glypican-2 bound to MK and suggested that MK-glypican-2 interactions participate in neuronal cell migration and neurite outgrowth. In addition, we observed different localization of epitope-tagged glypican-2 and syndecan-3 on the surface of N2a cells; the result suggested that they may play different roles in MK-mediated neural function.

Animals↗
PubMed2001

Syndecan-4 deficiency increases susceptibility to kappa-carrageenan-induced renal damage.

SUMMARY: The expression and roles of syndecan-4 in the kidney were investigated. Syndecan-4 expression was detected in the ureteric bud invaginating into the metanephric mesenchyme at 11.5 gestational days, and remained in the collecting ducts, distal renal tubules, glomeruli, and some capillaries between renal tubules until the mature kidney stage. However, organogenesis of the kidney was normal in syndecan-4-deficient (Synd4[-/-]) mice. Although most renal functions of Synd4(-/-) mice were not impaired, a significant increase in susceptibility to kappa-carrageenan-induced renal damage was observed in these mice. kappa-Carrageenan was heavily deposited in the collecting ducts of Synd4(-/-) mice and caused obstructive nephropathy, leading to death of 7 of 24 Synd4(-/-) mice within 7 days after administration, whereas none of 24 Synd4(+/+) mice died. After administration of kappa-carrageenan, blood urea nitrogen of Synd4(-/-) mice was significantly higher than that of Synd4(+/+) mice. Thus, syndecan-4 may function to prevent kappa-carrageenan deposition in the collecting ducts.

Animals↗
PubMed2001

In situ visualization of ultraviolet-light-induced DNA damage repair in locally irradiated human fibroblasts.

We have developed a novel method that uses a microfilter mask to produce ultraviolet-induced DNA lesions in localized areas of the cell nucleus. This technique allows us to visualize localized DNA repair in situ using immunologic probes. Two major types of DNA photoproducts [cyclobutane pyrimidine dimers and (6-4) photoproducts] were indeed detected in several foci per nucleus in normal human fibroblasts. They were repaired at those localized sites at different speeds, indicating that DNA photoproducts remain in relatively fixed nuclear positions during repair. A nucleotide excision repair protein, proliferating cell nuclear antigen, was recruited to the sites of DNA damage within 30 min after ultraviolet exposure. The level of proliferating cell nuclear antigen varied with DNA repair activity and diminished within 24 h. In contrast, almost no proliferating cell nuclear antigen fluorescence was observed within 3 h in xeroderma pigmentosum fibroblasts, which could not repair either type of photolesion. These results demonstrate that this technique is useful for visualizing the normal nucleotide excision repair process in vivo. Interestingly, however, in xeroderma pigmentosum cells, proliferating cell nuclear antigen appeared at ultraviolet damage sites after a delay and persisted as late as 72 h after ultraviolet exposure. This result suggests that this technique is also valuable for examining an incomplete or stalled nucleotide excision repair process caused by the lack of a single functional nucleotide excision repair protein. Thus, the technique provides a powerful approach to understanding the temporal and spatial interactions between DNA damage and damage-binding proteins in vivo.

Cell Line↗
PubMed2001

Alcohol and aldehyde dehydrogenase gene polymorphisms and oropharyngolaryngeal, esophageal and stomach cancers in Japanese alcoholics.

Alcohol dehydrogenase-2 (ADH2) and aldehyde dehydrogenase-2 (ALDH2) gene polymorphisms play roles in ethanol metabolism, drinking behavior and esophageal carcinogenesis in Japanese; however, the combined influence of ADH2 and ALDH2 genotypes on other aerodigestive tract cancers have not been investigated. ADH2/ALDH2 genotyping was performed on lymphocyte DNA samples from Japanese alcoholic men (526 cancer-free; 159 with solitary or multiple aerodigestive tract cancers, including 33 oropharyngolaryngeal, 112 esophageal, 38 stomach and 22 multiple primary cancers in two or three organs). After adjustment for age, drinking and smoking habits, and ADH2/ALDH2 genotypes, the presence of either ADH2*1/2*1 or ALDH2*1/2*2 significantly increased the risk for oropharyngolaryngeal cancer [odds ratios (ORs), 6.68 with ADH2*1/2*1 and 18.52 with ALDH2*1/2*2] and esophageal cancer (ORs, 2.64 and 13.50, respectively). For patients with both ADH2*1/2*1 and ALDH2*1/2*2, the risks for oropharyngolaryngeal and esophageal cancers were enhanced in a multiplicative fashion (OR = 121.77 and 40.40, respectively). A positive association with ALDH2*1/2*2 alone was observed for stomach cancer patients who also had oropharyngolaryngeal and/or esophageal cancer (OR = 110.58), but it was not observed for those with stomach cancer alone. Furthermore, in the presence of ALDH2*1/2*2, the risks for multiple intra-esophageal cancers (OR = 3.43) and for esophageal cancer with oropharyngolaryngeal and/or stomach cancer (OR = 3.95) were higher than the risks for solitary intra-esophageal cancer and for esophageal cancer alone, but these tendencies were not observed for ADH2*1/2*1 genotype. Alcoholics' population attributable risks due to ADH2/ALDH2 polymorphisms were estimated to be 82.0% for oropharyngolaryngeal cancer and 63.9% for esophageal cancer.

Adult↗
PubMed2001

A splicing factor, Prp8: preferential localization in the testis and ovary in adult mice.

Prp8 is a splicing factor of 220 kDa originally identified in yeast and is a component of the U5 small nuclear ribonucleoprotein particle. Mouse Prp8 cDNA was cloned and shown to share 62.6 and 68.2% sequence identity with the yeast homologue at the amino acid and nucleotide level, respectively, while it differs by only 3 amino acid residues from the human homologue. During mouse embryogenesis, Prp8 is expressed intensely at day 9.5 of gestation, and its expression decreases progressively during embryogenesis. In adult mice, Prp8 is expressed strongly in the testis and moderately in the ovary. in situ hybridization analysis revealed that Prp8 is preferentially expressed in the outer cell layer in the testis, probably in the spermatogonia and primary spermatocytes, and in granulosa cells in the ovary. In Caenorhabditis elegans, microinjection of a double stranded RNA corresponding to a portion of the Prp8 sequence results in the arrest of embryogenesis at the late-gastrulation stage. These results suggest that Prp8 plays an important role in reproduction and development. Prp8 was shown to bind to midkine (MK), a heparin-binding growth factor. Since Prp8 expression partially overlaps with the sites of action of MK, it is possible that binding to Prp8 is involved in part of MK signaling.

Aging↗
PubMed2001

Molecular cloning and expression of endo-beta-N-acetylglucosaminidase D, which acts on the core structure of complex type asparagine-linked oligosaccharides.

Endo-beta-N-acetylglucosaminidase D (Endo D) produced by Streptococcus pneumoniae cleaves the di-N-acetylchitobiose structure in asparagine-linked oligosaccharides. The enzyme generally acts on complex type oligosaccharides after removal of external sugars by neuraminidase, beta-galactosidase, and beta-N-acetylglucosaminidase. We cloned the gene encoding the enzyme and expressed it as a periplasm enzyme in Escherichia coli. The first 37 amino acids in the predicted sequence are removed in the mature enzyme, yielding a protein with a molecular mass of 178 kDa. The substrate specificity of the recombinant enzyme is indistinguishable from the enzyme produced by S. pneumoniae. Endo-beta-N-acetylglucosaminidase A (Endo A) from Arthrobacter protophormiae, the molecular mass of which is 72 kDa, had 32% sequence identity to Endo D, starting from the N-terminal sides of both enzymes, although Endo A hydrolyzes high-mannose-type oligosaccharides and does not hydrolyze complex type ones. Endo D is not related to endo-beta-N-acetylglucosaminidases H, F(1), F(2), or F(3), which share common structural motifs. Therefore, there are two distinct groups of endo-beta-N-acetylglucosaminidases acting on asparagine-linked oligosaccharides. The C-terminal region of Endo D shows homology to beta-galactosidase and beta-N-acetylglucosaminidase from S. pneumoniae and has an LPXTG motif typical of surface-associated proteins of Gram-positive bacteria. It is possible that Endo D is located on the surface of the bacterium and, together with other glycosidases, is involved in virulence.

Amino Acid Sequence↗
PubMed2001

Mechanical properties of tendon and aponeurosis of human gastrocnemius muscle in vivo.

Load-strain characteristics of tendinous tissues (Achilles tendon and aponeurosis) were determined in vivo for human medial gastrocnemius (MG) muscle. Seven male subjects exerted isometric plantar flexion torque while the elongation of tendinous tissues of MG was determined from the tendinous movements by using ultrasonography. The maximal strain of the Achilles tendon and aponeurosis, estimated separately from the elongation data, was 5.1 +/- 1.1 and 5.9 +/- 1.6%, respectively. There was no significant difference in strain between the Achilles tendon and aponeurosis. In addition, no significant difference in strain was observed between the proximal and distal regions of the aponeurosis. The results indicate that tendinous tissues of the MG are homogeneously stretched along their lengths by muscle contraction, which has functional implications for the operation of the human MG muscle-tendon unit in vivo.

Achilles Tendon↗
PubMed2001

Enhancement of diphtheria toxin-induced apoptosis in Vero cells by combination treatment with brefeldin A and okadaic acid.

In the present study, we compared the abilities of ricin and diphtheria toxin to induce apoptosis in Vero cells. The cytolysis and DNA fragmentation by ricin paralleled its protein synthesis inhibitory activity. However, unlike ricin, diphtheria toxin could induce neither cytolysis nor DNA fragmentation in Vero cells up to very high concentration, in spite of the fact that Vero cells were even more sensitive to protein synthesis inhibition by diphtheria toxin than ricin. Interestingly, coexistence of brefeldin A (BFA) and okadaic acid (OA) significantly enhanced diphtheria toxin-mediated cytolysis and DNA fragmentation without affecting the activity of protein synthesis inhibition. Ammonium chloride almost completely abolished the ability of diphtheria toxin to induce apoptosis in the presence of BFA and OA as well as the protein synthesis inhibitory activity. The mutant CRM 197, which does not catalyze the ADP ribosylation of elongation factor-2 (EF-2), failed to induce apoptosis in Vero cells even in the presence of BFA and OA. Thus, translocation of diphtheria toxin into the cytosol and subsequent enzymatic inactivation of EF-2 may be necessary steps to induce apoptosis. Taken together our results suggest that protein synthesis inhibition by toxins is not sufficient to induce apoptosis, and underlying mechanisms of apoptosis induction may be distinct between ricin and diphtheria toxin. Since a morphological change in the Golgi complex was observed in Vero cells treated with BFA and OA, modulation of the Golgi complex by these reagents may be partly responsible for enhanced apoptosis induction by diphtheria toxin.

4-Chloro-7-nitrobenzofurazan↗
PubMed2001

An integrase facilitates long-lasting foreign gene expression in vivo in mouse spermatogenic cells.

The objective of the present study was to attain long-lasting foreign gene expression in vivo in spermatogenic cells in the mouse testis for establishing spermatogenic-cell mediated gene transformation. Prior to in vivo gene transfer, surgical cryptorchidism was performed by retaining the testis into the abdominal cavity for 1 month to remove differentiated spermatogenic cells. Subsequently, in vivo gene transfer was conducted by electroporation with a lacZ reporter gene in combination with a retroviral integrase gene, and the testis was descended immediately to the scrotum to recover from the cryptorchidism, and restart spermatogenesis. At 1 month post-transfection in vivo, lacZ gene expression was detected in some spermatocyte-like cells in seminiferous tubules of the mouse testis. However, the recovery period of 1 month appeared to be too short, since no elongated and fully differentiated spermatids were found. At 2 months post-transfection, fully differentiated spermatogenic cells expressing the lacZ gene, albeit at low frequency, were detected when the integrase gene was co-transfected, while virtually no lacZ-positive cells were found in the absence of the integrase gene. It was concluded, therefore, that stable transformation of spermatogenic cells in vivo would be facilitated by integrase gene co-transfection.

Journal Article↗
PubMed2001

Purification and characterization of bifunctional alginate lyase from Alteromonas sp. strain no. 272 and its action on saturated oligomeric substrates.

A marine bacterium (strain No. 272) isolated from sea mud in Omura Bay produced an alginate lyase and was classified as an Alteromonas species. The enzyme was purified from the culture medium of the bacterium by DEAE-Cellulofine, Sephadex G-100 gel chromatography to an electrophoretically homogeneous state in the presence and absence of SDS. The molecular mass of the enzyme was 23 and 33.9 kDa on Sephadex G-100 column chromatography and SDS-polyacrylamide gel electrophoresis, respectively, with an isoelectric point of 3.8. The predominant secondary structure of the enzyme was found to be most likely beta-structure by circular dichroism. The enzyme was most active at pH 7.5-8.0 and stable around pH 5-11. The enzyme was more labile in Tris-HCI buffer (pH 7.0) to heat treatment, than in phosphate buffer (pH 7.0). No of metal ions significantly affected the enzyme activity. The enzyme acted on sodium alginate in an endo-type manner and on two components of alginate, poly-alpha1,4-L-guluronate and poly-beta1,4-D-mannuronate, as judged by routine ultraviolet assay (235 nm) and circular dichroic spectral changes of the substrates. However, the coexisting poly-alpha1,4-L-guluronate and poly-beta1,4-D-mannuronate apparently interacted with the enzyme in a competitive manner. Although the enzyme depolymerized alginate in an endo-type, it did not act on trimeric guluronate and mannuronate, but on the tetramers or more. The kinetic analyses showed that kcat/Km for each oligomer was larger for the guluronate oligomers than for the mannuronate ones, and that the subsite structure of the enzyme most likely consisted of six binding sites from the intrinsic reaction rate constant (kint) and intrinsic substrate binding constant (Kint).

Alginates↗
PubMed2001

In vivo gene electroporation in skeletal muscle with special reference to the duration of gene expression.

To determine the limits of the duration of in vivo transferred foreign gene expression, we conducted electroporation (EP), a powerful non-viral means of gene transfer for living animals, into skeletal muscle of rats and mice with a luciferase, GFP or erythropoietin (EPO)-encoding reporter plasmid. The luciferase reporter plasmid was used for optimization of EP conditions, while GFP and EPO plasmids were used for monitoring the duration of gene expression. In the rat, increased hematocrit levels were maintained for at least 9 weeks with approximately a 3-fold increase in plasma EPO protein concentration at 4 weeks post-transfection. In the mouse, the GFP plasmid transfer confirmed that the reporter gene expression lasted as long as 3 months post-transfection. By introducing the EPO gene in vivo in the mouse, increased hematocrit levels revealed that duration of reporter gene expression was at least 14.5 months after in vivo gene EP into skeletal muscle. These results implicate an excellent potential of in vivo gene EP, applicable to both experimental and therapeutic purposes.

Animals↗
PubMed2001

In vivo gene electroporation confers nutritionally-regulated foreign gene expression in the liver.

Whether or not nutritionally-regulated foreign gene expression in vivo is achievable was examined in mouse liver after in vivo gene transfer by electroporation (EP). Electric pulses were applied to a left liver lobe immediately after injection of a luciferase reporter gene driven by the liver-type phosphoenolpyruvate carboxykinase (PEPCK) gene promoter. Cooling treatments especially with solid carbon dioxide in the transfection site prior to the in vivo gene EP increased reporter gene expression by a factor of 100. Body bioluminescence imaging also confirmed strong expression of the in vivo transferred reporter gene in a transfected area of the liver. Fasting conferred a 13-fold increase in the reporter gene expression in vivo in the liver when driven by the liver-type PEPCK promoter, whereas virtually no induction was found either by the SV40 promoter or by the same PEPCK promoter in the muscle when the mice were fasted. The administration of cAMP mimicked the fasting-induced reporter gene expression by the PEPCK promoter in the liver of fed mice. These results implicate that nutritionally-regulated foreign gene expression in vivo is attainable at least locally in the liver by a simple and convenient non-viral gene EP method.

Animals↗
PubMed2001

Elevated gastrin secretion by in vivo gene electroporation in skeletal muscle.

Whether or not in vivo gene transfer of gastrin gene into skeletal muscle by electroporation could modify gastrin secretion was examined. The expression plasmid vector, either pMEPrGaspA encoding the rat gastrin gene or pEGFP-N1 encoding the GFP reporter gene was injected into M. rectus abdominis of rats or M. biceps formis of mice. Subsequently, square electric pulses of direct current were applied six times at 25 V with a loading period of 100 msec per pulse. Clear foreign gene expression in the skeletal muscle was demonstrated by both GFP fluorescence and immunostaining of rat gastrin. Time course changes in plasma gastrin levels after transfection revealed that in rats, gastrin gene transfer significantly increased the plasma gastrin level for 4 weeks post-transfection (P<0.05), but the difference diminished at the end of the 10-week period. In mice, plasma gastrin level elevated similarly for 3 weeks, and pH of gastric contents decreased in the gastrin gene transfected group compared with the control counterpart (P<0.05). These findings suggest that localized in vivo gene transfer by electroporation allows skeletal muscle to become an artificial endocrine tissue for hormonal manipulation of animals.

Animals↗
PubMed2001

Colocalization of neuropilin-1 and Flk-1 in retinal neovascularization in a mouse model of retinopathy.

PURPOSE: To investigate the mechanisms of the development of retinal neovascularization, the localizations of vascular endothelial (VEGF) receptors Flk-1 and neuropilin (NP)-1 mRNAs were examined. METHODS: The model of retinopathy of prematurity (ROP) was produced by ischemia-induced ocular neovascularization, by exposing postnatal day-7 mice to 75% oxygen for 5 days and then returning them to room air for 5 days. Retinal neovascularization was visualized by injection of fluorescein-dextran. Expression of Flk-1 and NP-1 mRNAs were examined by in situ hybridization with flatmount and serial sections of the retina. The localization of NP-1 was also confirmed by immunohistochemistry. Blood vessel patterns were characterized by immunohistochemical localization of von Willebrand factor (vWF). RESULTS: Flatmount in situ hybridization showed intense expression of NP-1 and Flk-1 mRNAs colocalized in the area of neovascularization. In situ hybridization of serial sections of the retina revealed that expression of Flk-1 and NP-1 was restricted to neovascularized vessels of the retina from ROP mice. CONCLUSIONS: The restricted expression of Flk-1 and NP-1 on neovascularized vessels suggests that these molecules may play important roles in retinal neovascularization. This is the first report of the colocalization of NP-1 and Flk-1 on neovascularized vessels of the retina from ROP mice.

Animals↗
PubMed2001

Efficacy of cutting balloon angioplasty for in-stent restenosis: an intravascular ultrasound evaluation.

BACKGROUND: The increase in the use of stents has seen the increasing emergence of in-stent restenosis (ISR). Reports suggest that the Cutting Balloon (Interventional Technologies, San Diego, California) may be a useful treatment modality for this new clinical entity. METHODS: In this study, we compared the efficacy of Cutting Balloon angioplasty (CBA) with conventional balloon angioplasty (PTCA) for ISR in 47 patients (47 lesions). Results were evaluated with intravascular ultrasound (IVUS). The CBA group included 25 patients (mean age, 65 +/- 78 years; 7 females) and the PTCA group included 22 patients (mean age, 69 +/- 51 years; 6 females). RESULTS: The procedural success rate was 100% in both groups. IVUS showed that luminal area acute gain was larger in the CBA group (2.5 +/- 0.8 mm2) compared to the PTCA group (1.8 +/- 1.0 mm2), while late loss was smaller in the CBA group (0.5 +/- 0.4 mm2) compared to the PTCA group (1.3 +/- 0.5 mm2). The change in total area was similar in both groups. The increase in area at the stented portion was 0.4 +/- 0.8 mm2 in the CBA group and 1.2 +/- 0.5 mm2 in the PTCA group. The restenosis rate at follow-up (mean follow-up, 5.4 months) was higher in PTCA patients (59%) than in the CBA patients (24%). CONCLUSION: CBA may result in no increase in total vessel area, a constant stent area, a decrease in plaque area, and an increase in lumen area (induced by the decrease in plaque area). Our IVUS findings suggest that compared to PTCA, the dilatation mechanism of CBA may be associated with reduced dilatation of both the total vessel area and the stent area for ISR. The mechanism of this modality may minimize injury to the intimal membrane and may potentially be a primary device for in-stent restenosis in the future.

Aged↗
PubMed2001

[A case of chronic hypersensitivity pneumonitis due to wild pigeons].

A 61-year-old woman was admitted to the Oita Medical University Hospital because of a nonproductive cough and exertional dyspnea. Interstitial changes had been seen on her chest radiograph 5 years previously, but no respiratory symptoms were identified at that time. On admission, chest radiography revealed linear and ground-glass opacities in the middle and lower lung fields. Computed tomography provided evidence of bronchiectasis and micro-honeycombing of the lungs, while lymphocyte and neutrophil counts in the bronchoalveolar lavage fluid were increased. Transbronchial lung biopsy demonstrated alveolitis and Masson's bodies. The patient was not a pigeon breeder, but she could have been exposed to pigeons at her workplace. Indeed, she had specific antibodies against pigeon serum and droppings, and her peripheral lymphocytes showed proliferation in response to pigeon serum. A positive provocation test involving inhalation of pigeon serum confirmed that she had chronic hypersensitivity pneumonitis caused by allergy to pigeons. This is a rare case of chronic hypersensitivity pneumonitis associated with wild pigeons, that progressed to pulmonary fibrosis. Antigen provocation testing proved to be of great value.

Alveolitis, Extrinsic Allergic↗
PubMed2001

Clinical outcome of stent implantation in small coronary arteries using different types of coronary stents.

PURPOSE: We evaluated the results of stent placement in small coronary arteries. SUBJECTS: The subjects were divided into 2 groups: the first contained 911 lesions treated with stenting in the coronary arteries (stent group), and the second contained 1,203 background- and patient-matched lesions treated with balloon angioplasty (POBA group). There was no significant difference in the background of patients or lesions between the groups. A "small coronary artery" was defined as a coronary artery with a reference vessel diameter < 3.0 mm. RESULTS: There was no significant difference in incidence of acute myocardial infarction (AMI), coronary artery bypass grafting, or death between the groups. In the stent group, acute occlusion (0.8%) and subacute thrombosis (2.1%) occurred. The restenosis rate of 29.8% in the stent group was significantly lower than in the POBA group (38.2%; p < 0.01). The restenosis rate of 19.4% in stented vessels 3.0 mm diameter was significantly lower than in vessels < 3.0 mm diameter (29.8%; p < 0.01). The rate of restenosis was 22.9% for the Multi-Link stent, 24.4% for the NIR stent, 34.1% for the GFX stent, and 35.3% for the PS stent. The restenosis rate of 23.8% in stented vessels > 2.5 mm diameter and < or = 20 mm length was significantly lower than in vessels , < or = 2.5 mm diameter and > 20 mm length (32.7%; p < 0.01). Factors associated with restenosis, analyzed using a stepwise multivariate logistic regression model, included ostial lesions and post-procedural minimum lumen diameter. CONCLUSIONS: Stent implantation in vessels < 3.0 mm diameter using a newly designed coronary stent yielded favorable clinical results, while there was a high prevalence of restenosis, leading to diffused stenotic lesions, in vessels < 2.5 mm diameter.

Aged↗