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Biomedical subjects

Y Ito

Publications and source records attributed to Y Ito.

At least 271 records · Page 15Linked to original sources
PubMed2001

Localization of chondrocyte precursors in periosteum.

OBJECTIVE: Periosteal chondrogenesis is relevant to cartilage repair and fracture healing. Periosteum contains two distinct layers: a thick, outer fibrous layer and a thin, inner cambium layer which is adjacent to the bone. Specific chondrocyte precursors are known to exist in periosteum but have not yet been identified. In this study, the location of the chondrocyte precursors in periosteum was determined. METHOD: One hundred and twenty periosteal explants from 30 2-month-old NZ rabbits were cultured for up to 42 days. Histomorphological changes and spatio-temporal localization of Col. II mRNA and protein were analysed. RESULTS: On day 7, chondrocyte differentiation appeared in the most juxtaosseous region in the cambium layer. Col. II mRNA and protein were also evident in the same region. By day 14, chondrocyte differentiation progressed further into the juxtaosseous cambium layer, as did Col. II mRNA and protein. With growth of the neocartilage, the cambium layer gradually diminished to the extent that by 21-28 days it was no longer evident. Cartilage growth was significant and followed an appositional pattern, growing away from the fibrous layer. The fibrous layer remained essentially unchanged from 0-42 days, without evidence of hypertrophy or atrophy. Col. II mRNA expression was never seen in the fibrous layer. CONCLUSION: From these data, three conclusions can be drawn concerning chondrogenesis from periosteum: (1) the chondrocyte precursors are located in the cambium layer of periosteum; (2) chondrogenesis commences in the juxtaosseous area in the cambium layer and progresses from the juxtaosseous region to the juxtafibrous region of the cambium layer; (3) neocartilage growth is appositional, which displaces the fibrous layer away from the cartilage already formed, as new cartilage is formed between these two layers. These findings suggest that the least differentiated (stem or reserve) cells are located in the cambium layer furthest from the bone. CLINICAL RELEVANCE: These findings show that the chondrocyte precursors are located in the cambium layer of periosteum. Preservation of this layer is essential for chondrogenesis. As neocartilage growth is appositional, away from the fibrous layer, it can be expected that the new cartilage deposited in and adjacent to a periosteal graft would be expected to be located on the side of the cambium layer, rather than on the side of the fibrous layer of the graft.

Animals↗
PubMed2001

Laparoscopic ultrasonography for resection of insulinomas.

BACKGROUND: There have been few reports on the use of laparoscopic ultrasonography as an aid for the resection of insulinomas. In this study, we review our experience with laparoscopic ultrasonography for the intraoperative localization and resection of insulinomas. METHODS: We attempted laparoscopic resection of insulinomas in 7 patients (median age, 50 years) during a 4-year period. Preoperative imaging showed that 1 of the insulinomas was located in the head of the pancreas, 2 were located in the body, and 4 were located in the tail. RESULTS: We identified the insulinomas in all 7 patients with laparoscopic ultrasonography. In 6 of the patients, the insulinomas were laparoscopically resectable, either by enucleation (4 patients) or by resection of the pancreatic tail (2 patients). Conversion to laparotomy was necessary for the insulinomas in the head of the pancreas because they were close to the portal vein and the major pancreatic duct. All patients showed improvement in their hypoglycemia after the operations. Minor leakage of pancreatic juice occurred in 4 patients, and this was resolved with conservative treatment. CONCLUSIONS: Laparoscopic ultrasonography is useful for the intraoperative localization of insulinomas. Laparoscopy is a safe and feasible technique for resecting insulinomas located in the body or tail of the pancreas.

Adult↗
PubMed2001

Nitric oxide participates in cataract development in selenite-treated rats.

PURPOSE: The role of nitric oxide in the development of selenite-induced cataracts in rats was examined using nitric oxide synthase (NOS) inhibitors. METHODS: Subcutaneous injection of sodium selenite was used to induce cataracts in rats, with or without pretreatment with NOS inhibitors. The anterior eye segment analysis system (EAS-1000, Nidek) was used to measure lens opacity. The glutathione content of the lenses was determined by an HPLC method and the Ca2+ content by atomic absorption spectrometry. Nitrite, a stable metabolite of nitric oxide, was determined fluorometrically. NADPH-diaphorase activity staining and Western blot analysis were used to determine NOS levels. RESULTS: Administration of the NOS inhibitor, NG-nitro-L-arginine methyl ester (L-NAME), inhibited lens opacification in selenite-treated rats. NG-nitro-d-arginine methyl ester, an inactive enantiomer of l-NAME, had no effect. Aminoguanidine, another NOS inhibitor, also inhibited the development of cataracts in a dose-dependent manner. On the other hand, L-arginine, a substrate of NOS, accelerated the development of cataracts. Although the opacification of the lenses was apparent approximately 3 days after selenite injection, the nitrite level was increased within one day. In addition, NOS was induced in the eye within one day of selenite injection. CONCLUSIONS: The present study demonstrated that NOS inhibitors prevented the development of cataracts in selenite-treated rats. The results also suggest that nitric oxide had an important role in the development of selenite-induced cataracts.

Animals↗
PubMed2001

Expression of plasma membrane Ca(2+)-ATPase in lenses from normal and hereditary cataract UPL rats.

PURPOSE: The regulation of calcium concentration in lens cells is important in the mechanisms of cataractogenesis. The Ca( 2+) level in cells is controlled by plasma membrane Ca(2+)-ATPase (PMCA). PMCA has several isoforms that are distributed in various cell types in the body. In this study, we investigated the PMCA mRNA expression in normal lenses and in lenses from rats with newly developed hereditary cataracts. METHODS: The rats used were the UPL strain of Sprague-Dawley rats, with (UPL) and without (normal) the dominant gene for cataracts. PMCA mRNA expression in the lens, brain, liver and kidney in the normal and UPL rats was detected by reverse transcription-PCR using isoform specific primers. Partial cDNA sequences of the lens PMCA were also determined. RESULTS: PMCA1, 2, 3 and 4 were expressed in the brain and kidney. Distinct from the brain, liver and kidney, only one isoform of PMCA, PMCA1b, was expressed in both normal and UPL rat lenses. Sequences of PMCA in normal and UPL rat lenses were not different. CONCLUSIONS: The present study demonstrated that PMCA1b is the only form of PMCA present in both normal and UPL rat lenses.

Animals↗
PubMed2001

Involvement of inducible nitric oxide synthase in cataract formation in Shumiya cataract rat (SCR).

PURPOSE: Our previous results showed that the oral administration of aminoguanidine (AG), an inhibitor of inducible nitric oxide synthase (iNOS), strongly suppresses lens opacification in Shumiya cataract rat (SCR). Therefore, we examine whether iNOS is upregulated and involved in cataract formation in SCR. METHODS: The expressions of iNOS mRNA and iNOS protein in SCR lenses were examined by RT-PCR and Western blotting, respectively. Calpain-mediated alphaB-crystallin proteolysis was analyzed by Western blotting using antibody specific to the calpain-generated fragment of alphaB-crystallin. Lens opacification was analyzed using computerized image analysis software connected to the Anterior Eye Segment Analysis System (EAS-1000, Nidek). Calcium contents in lenses were measured by atomic absorption spectrophotometry. RESULTS: High levels of iNOS mRNA and iNOS protein are expressed in cataractous lenses compared with normal lenses. The increases in their expression are markedly suppressed by the oral administration of AG, which acts to prevent lens opacification. The induction of iNOS protein is observed before the elevation in calcium content and the acceleration of calpain-mediated proteolysis, both of which are closely related to the development of lens opacification. CONCLUSIONS: These findings strongly suggest that iNOS is involved in cataract formation in SCR. The induction of iNOS occurs prior to the elevation of calcium content and its induction is inhibited by AG-treatment. Considering our previous result that the elevation of calcium content is also prevented by AG-treatment, it is conceivable that upregulation of iNOS causes calcium influx into lens cells and the subsequent activation of calpain.

Animals↗
PubMed2001

Expression and clinical significance of the erbB family in intrahepatic cholangiocellular carcinoma.

The type I family of growth factor receptors is known to play a role in the development of several carcinomas, but its role in hepatic malignancies is not clearly understood. In this study we investigated the expression of this family of EGF-R, c-erbB-2, c-erbB-3 and c-erbB-4 in 38 intrahepatic cholangiocellular carcinomas (CCC) by means of immunohistochemistry. EGF-R expression was related to lymph node metastasis, aberrant p53 expression, proliferating activity, and carcinoma differentiation. c-erbB-2 expression was observed in more than 50% of the cases, but was not related to any clinicopathological features, c-erbB-3 expression was linked to lymph node metastasis, and c-erbB-4 expression was directly related to proliferating activity and lymph node metastasis. These results indicate that: 1) EGF-R contributes greatly to CCC progression, and c-erbB-3 and c-erbB-4 have roles similar to but less than that of EGFR, and 2) c-erbB-2 is expressed in CCC in high incidence, but its clinical role in CCC remains unclear.

Bile Duct Neoplasms↗
PubMed2001

Hemispheric asymmetry in the induction of false memories.

The purpose of this study was to investigate hemispheric asymmetry in verbal memory by using a false recognition paradigm and a standard list learning paradigm, which can induce high false recognition for semantically related distractors. The experiment showed that the LH could discriminate the targets from the related distractors more accurately than the RH. This result was attributed to the hemispheric difference in the hit rate rather than in false recognition. The results of the present study suggest that the model of RH coarse semantic coding and LH fine semantic coding is applicable not only to language processing but also to verbal memory.

Journal Article↗
PubMed2001

HMGN4, a newly discovered nucleosome-binding protein encoded by an intronless gene.

We describe a newly discovered nuclear protein, HMGN4, that is closely related to the canonical HMGN2 nucleosome-binding protein. The protein is encoded by an intronless gene, which, in humans, is located in the hereditary hemochromatosis [correction of hemachromatosis] region at position 6p21.3. A single approximately 2-kb HMGN4 mRNA was found to be expressed, in variable amounts, in all human tissues tested; however, the HMGN4 transcript was significantly less abundant than that of HMGN2. The HMGN4 protein could be detected in HeLa cells by Western analysis with an antibody elicited against a unique region of the protein. Transfection of HeLa cells with a plasmid expressing HMGN4-GFP indicated that the protein localizes to the nucleus. Our results expand the multiplicity of the HMGN protein family and increase the known cellular repertoire of nucleosome-binding proteins.

Animals↗
PubMed2001

Sequence-specific interaction between the disintegrin domain of mouse ADAM 3 and murine eggs: role of beta1 integrin-associated proteins CD9, CD81, and CD98.

ADAM 3 is a sperm surface glycoprotein that has been implicated in sperm-egg adhesion. Because little is known about the adhesive activity of ADAMs, we investigated the interaction of ADAM 3 disintegrin domains, made in bacteria and in insect cells, with murine eggs. Both recombinant proteins inhibited sperm-egg binding and fusion with potencies similar to that which we recently reported for the ADAM 2 disintegrin domain. Alanine scanning mutagenesis revealed a critical importance for the glutamine at position 7 of the disintegrin loop. Fluorescent beads coated with the ADAM 3 disintegrin domain bound to the egg surface. Bead binding was inhibited by an authentic, but not by a scrambled, peptide analog of the disintegrin loop. Bead binding was also inhibited by the function-blocking anti-alpha6 monoclonal antibody (mAb) GoH3, but not by a nonfunction blocking anti-alpha6 mAb, or by mAbs against either the alphav or beta3 integrin subunits. We also present evidence that in addition to the tetraspanin CD9, two other beta1-integrin-associated proteins, the tetraspanin CD81 as well as the single pass transmembrane protein CD98 are expressed on murine eggs. Antibodies to CD9 and CD98 inhibited in vitro fertilization and binding of the ADAM 3 disintegrin domain. Our findings are discussed in terms of the involvement of multiple sperm ADAMs and multiple egg beta1 integrin-associated proteins in sperm-egg binding and fusion. We propose that an egg surface "tetraspan web" facilitates fertilization and that it may do so by fostering ADAM-integrin interactions.

ADAM Proteins↗
PubMed2001

Influence of postsurgical residual tumor volume on local control in radiotherapy for maxillary sinus cancer.

BACKGROUND: The aim was to study the influence of postsurgical gross residual tumor volume on local control of maxillary sinus cancer treated with radiotherapy combined with debulking surgery. METHODS: Forty-three patients who underwent combined surgery and radiotherapy (50-72 Gy, median 60 Gy) for squamous cell carcinoma of the maxillary sinus were reviewed. Gross residual tumor volume (GRTV) after surgery was measured on computed tomograms obtained during the radiotherapy planning. Patients were classified according to GRTV as follows: group AA, GRTV = 0 (microscopic residual, n = 2); group A, GRTV < 10 cm3 (n = 24); group B, 10-40 cm3 (n = 9); and group C, > or = 40 cm3 (n = 8). The relationship between local control and GRTV was analyzed using univariate and multivariate analysis. RESULTS: The 2-year local control rate for all patients was 62%. The differences in local control rates between groups AA, A and B were not significant (P > 0.05), but the rate was significantly lower in group C than in the other groups (69% at 2 years vs 31% at 1 year, P < 0.001). Multivariate analysis showed that GRTV (P = 0.002) and histological differentiation (poorly differentiated histology was favorable, P = 0.035) were independent prognostic factors and that intra-arterial chemotherapy and administered total dose were not. Local control in groups A and B significantly depended on the total dose of radiotherapy, with 2-year control rates of patients receiving 50 Gy (n = 6) and > or = 60 Gy (n = 27) of 17% vs 79%, respectively (P < 0.001). CONCLUSIONS: Our data suggest that adequate, not complete, debulking associated with a total radiotherapy dose of > or = 60 Gy can provide satisfactory local control for patients with squamous cell carcinoma of the maxillary sinus.

Carcinoma, Squamous Cell↗
PubMed2001

Therapeutic results of alternating chemoradiotherapy for nasopharyngeal cancer using cisplatin and 5-fluorouracil: its usefulness and controversial points.

BACKGROUND: The present study was conducted to evaluate the therapeutic results of alternating chemoradiotherapy for locally advanced nasopharyngeal cancer (NPC). METHODS: The subjects consisted of six patients with stage III nasopharyngeal cancer and 26 patients with stage IV nasopharyngeal cancer. Using 6 MV photons, radiotherapy was performed at an exposure of 1.8-2.0 Gy five times per week. That is, a total absorbed dose of 36-40 Gy was irradiated between the base of the skull and supraclavicular fossa. After decreasing the irradiation field, an absorbed dose of 26-30 Gy was additionally given thereafter. One course of chemotherapy consisted of the administration of 5-fluorouracil (5-FU) at a dose of 700 mg/m2/24 h for 5 days (days 1-5) and cisplatin (CDDP) at a dose of 50 mg/m2/24 h for 2 days (days 6-7) and a total of 2-3 courses of chemotherapy were performed. During the alternating chemoradiotherapy, chemotherapy was performed initially and 3-5 days after completing the chemotherapy, radiotherapy was performed for 3-4 weeks. Thereafter, chemotherapy and radiotherapy were performed alternately. RESULTS: The scheduled courses of alternating chemoradiotherapy were completed in 30 (94%) of 32 patients. Although one patient developed shock induced by metal allergy to CDDP, no severe adverse effects were noted in any other patients. In these 32 patients, the overall 5-year survival rate was 75% (95% confidence interval: 60-90%) and the progression-free survival rate was 63% (95% CI: 46-89%). CONCLUSIONS: This method of alternating chemoradiotherapy yielded higher or at least similar survival rates and lower toxicities than concurrent chemoradiotherapy and is worth trying in a multi-institutional study.

Adult↗
PubMed2001

Application of atomic scale STEM techniques to the study of interfaces and defects in materials.

Incoherent imaging and analysis techniques in the scanning transmission electron microscope (STEM) provide the potential to map changes in structure, composition and bonding that occur at materials interfaces and defects on the fundamental atomic scale. Such comprehensive characterization capabilities permit a detailed analysis of the structure-property relationships of interfaces and defects to be performed. In this paper, we discuss the resolution limits of such techniques in the JEOL 2010F STEM/TEM operating both under standard conditions and at elevated temperatures. Examples of the use of such techniques to quantify the atomic scale defect chemistry at interfaces and defects in perovskite oxides, the growth and structure of II-VI and III-V quantum dots and the electronic structure of threading dislocations in GaN will also be presented.

Journal Article↗
PubMed2001

Apoptosis in the normal human amnion at term, independent of Bcl-2 regulation and onset of labour.

This study was designed to detect apoptosis in the human amnion and to elucidate the signalling pathway involved in its regulation. Samples of human amnion were obtained from 34 women (weeks 11-42 of gestation) and studied using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling (TUNEL) method with light microscopy (LM) and transmission electron microscopy (TEM). Apoptotic regulators in the samples were studied by immunohistochemistry and caspase activity assay. The TUNEL method with LM demonstrated that the percentage of TUNEL-positive cells in the amniotic epithelium was the highest in weeks 40-41 of gestation (P < 0.05) independent of the onset of labour, and the cells were often detached from the epithelium into the amniotic cavity at term. The TUNEL method with TEM clearly showed the characteristic features of apoptosis such as the nuclear condensed chromatin with abundant free 3'-OH DNA ends, cell shrinkage and a decrease in the number of desmosomes, except for the presence of apoptotic bodies. Fas and Fas ligand (FasL) were constantly expressed on apical membranes of amniotic epithelial cells from weeks 16-27 through to 40-41 of gestation, while no Bcl-2 expression was observed throughout the gestational periods. Activities of caspase-3 and caspase-8, but not of caspase-9, were higher in weeks 40-41 than those from weeks 16-27 of gestation (P < 0.01). We conclude that apoptosis in term amniotic epithelium is independent of Bcl-2 regulation and onset of labour, and may play an important role in the fragility and rupture of human fetal membranes at term.

Amnion↗
PubMed2001

Evidence of G-A/A-G pair, not A-G/G-A pair, in SECIS element.

The decoding of selenocysteine (Sec) codon for selenoprotein translation in animals requires the SECIS (selenocysteine insertion sequence) element in the 3'-untranslated region (3'-UTR) of selenoprotein mRNA. It has been hypothesized that SECIS has G-A/A-G pairs, which are non-Watson-Crick base pairs, and are one of the most indispensable parts for Sec translation. However, DNA structure research has shown that the DNA loop structure was closed by a G-A pair (1), although there is little evidence for G-A stability in SECIS. Our aim was to investigate the existence of a G-A/A-G base pair by electrophoretic mobility and Tm measurement, and we found that G-A/A-G bases formed a stable pair, but A-G/G-A bases did not.

3' Untranslated Regions↗
PubMed2001

In vitro evidence for differential involvement of CTGF, TGFbeta, and PDGF-BB in mesangial response to injury.

BACKGROUND: Connective tissue growth factor (CTGF) is a profibrotic growth factor, which is upregulated in wound healing and renal fibrosis, including anti-Thy-1.1 nephritis. The kinetics of CTGF mRNA expression in anti-Thy-1.1 nephritis suggested that CTGF regulation might contribute to glomerular response to injury downstream of transforming growth factor-beta (TGFbeta). In anti-Thy-1.1 nephritis the initial damage is followed by mesangial repair and limited sclerosis, which involves mesangial cell (MC) activation (alpha-smooth-muscle actin (alphaSMA) expression), proliferation, migration, and extracellular matrix production. The present in vitro study addresses the possible role of CTGF in these different aspects of mesangial response to injury, and how CTGF activity might relate to effects of TGFbeta and platelet-derived growth factor-BB (PDGF-BB). METHODS AND RESULTS: Immunostaining and ELISA showed that alphaSMA expression and transformation of MC into myofibroblast-like cells was induced by TGFbeta, but not affected by PDGF-BB, CTGF, or neutralizing anti-CTGF antibodies. [(3)H]thymidine incorporation and Ki67 staining demonstrated that, unlike PDGF-BB, neither CTGF nor TGFbeta induced the proliferation of MC. In contrast, both CTGF and TGFbeta induced MC migration, as evidenced by approximation of wound edges in scrape-wounded, non-proliferating rat MC monolayers. In addition, fibronectin expression was upregulated by both CTGF and TGFbeta, as measured by dot-blot analysis. Anti-CTGF completely blocked the effect of added CTGF. Moreover, anti-CTGF significantly reduced TGFbeta-induced increase in fibronectin. CONCLUSION: It thus appears that CTGF is specifically involved in a subset of the adaptive changes of MC involved in mesangial repair and sclerosis, which makes it an interesting candidate target for future intervention strategies.

Actins↗
PubMed2001

Peptide mimics of monocyte chemoattractant protein-1 (MCP-1) with an antagonistic activity.

In this study, we attempted to analyze the peptide motifs recognized by 24822.111 and F9, monoclonal antibodies (mAbs) that inhibit the chemotactic activity of monocyte chemoattractant protein-1 (MCP-1), a member of the CC subfamily of chemokines. We isolated phage clones from a phage display library and identified six peptide motifs. One of these clones, C27, was strongly and specifically recognized by 24822.111 mAb, while another, G25, was similarly recognized by F9 mAb. Both the C27 motif and the G25 motif contain two cysteines in their sequences and have little homology to the primary amino acid sequence of MCP-1. These clones, however, bound to THP-1 cells, and the binding was competitively inhibited by MCP-1. The clones strongly inhibited the MCP-1-induced chemotaxis of human monocytes. The synthetic and intramolecularly disulfide-linked peptides of C27 and G25 (sC27 and sG25) also inhibited the chemotaxis induced by MCP-1, while their derivatives with serine in place of cysteine did not, suggesting the importance of the loop structure for the inhibition. These results suggest that sC27 and sG25 may mimic the MCP-1-binding domain to the MCP-1 receptor.

Amino Acid Sequence↗
PubMed2001

Differential control of cellular gene expression by diffusible and non-diffusible EGF.

Cell gene expression is affected by both the kind and mode of growth factor stimulation (diffusive vs. non-diffusive). Epidermal growth factor (EGF) was pattern-immobilized on a polystyrene plate. Although the growth of the rat phaeochromocytoma cell line PC12 is stimulated by diffusible EGF, and differentiation is stimulated by diffusible nerve growth factor (NGF), immobilized (non-diffusible) EGF stimulated PC12 differentiation. The immobilized EGF caused a long-lasting stimulation of the intracellular signal protein mitogen-associated protein MAP kinase (MAPK, also known as ERK) and p38 (a subfamily of the MAPK superfamily) in cells, as did diffusible NGF. The switching between growth stimulation and differentiation is considered to be due to the duration of the stimulus. The function of the biosignal conjugate was regulated using conjugation methodology.

Animals↗