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Biomedical subjects

T Eguchi

Publications and source records attributed to T Eguchi.

At least 19 recordsLinked to original sources
PubMed2006

RB silencing compromises the DNA damage-induced G2/M checkpoint and causes deregulated expression of the ECT2 oncogene.

As alterations in retinoblastoma (RB)/E2F pathway are commonly found in human cancers, the molecular mechanism underlying cell cycle deregulation caused by the mutations in the RB/E2F pathway needs to be investigated extensively. Compared with good understanding of RB/E2F functions in G1-S cell cycle progression, it is not fully understood how an abrogated RB pathway affects the G2-M phase of the cell cycle. Here, we report that disruption of RB accelerated G2-M progression in the presence of DNA damage by elevating the expression of a set of mitotic regulatory genes. We generated RB(+)- and (-)-matched cells using short hairpin RNA. In the RB(-) cells, the G2/M checkpoint mediated by a DNA-damaging agent was over-ridden. With microarray analysis, we found that the expression of key G2-M regulatory genes was upregulated in RB(-) cells. In particular, we demonstrated that the proto-oncogene ECT2 was directly regulated by E2Fs. Furthermore, suppression of ECT2 expression by small interfering RNA in RB(-) cells resulted in cytokinesis arrest, suggesting that RB(-) cells lack the regulation of E2F-mediated cytokinesis. These results indicate that aberrant ECT2 expression, observed in various human tumors, could be the direct result of RB/E2F pathway deficiency, thereby contributing to cell division in cancers.

Cell Division↗
PubMed2006

A 2-stage procedure combining maxillary advancement by distraction technique with mandibular setback surgery in patients with cleft lip and palate.

A 2-stage procedure combining maxillary advancement by distraction technique with mandibular setback surgery was used to correct jaw deformities in 5 patients with severe maxillary retrusion secondary to cleft lip and palate. First, a Le Fort I maxillary osteotomy was performed. Immediately after maxillary distraction, the distraction device was removed. The advanced maxilla was fixed with miniplates after adjusting the length and direction of advancement, and mandibular setback surgery was performed simultaneously to obtain a normal occlusal relationship. This 2-stage procedure resulted in stable occlusion and a markedly improved facial profile.

Adolescent↗
PubMed2006

Electrostatic potential screened by a two-dimensional electron system: a real-space observation by scanning-tunneling spectroscopy.

Scanning-tunneling spectroscopy at 5 K was used to investigate the electrostatic potential profile on the Si(111)-square root of 3 x square root of 3 Ag surface at subnanometer spatial resolution. The potential was measured from an energy-level shift of electronic states on the surface. The potential images obtained reveal that the potential drops around the steps and Ag adsorbates, upon which positive charges are presumably accumulated. The profiles of the reduced potentials are explained with the screening of potential due to the charges by two-dimensional electron gas (2DEG) existing on the surface. The Friedel oscillation, which results from the screening and has a period of the half Fermi wavelength of the 2DEG, was also observed in the potential images.

Journal Article↗
PubMed2005

Characterization of new monoclonal antibodies against porcine lymphocytes: molecular characterization of clone 7G3, an antibody reactive with the constant region of the T-cell receptor delta-chains.

A battery of mouse monoclonal antibodies (mAbs) reactive with porcine peripheral blood (PB) leukocytes was generated. Among the mAbs, 6F10 was found to react probably with cluster of differentiation (CD)8 alpha-chain, while 7G3 and 3E12 were found to recognize gammadelta T-cells, as revealed by two-color flow cytometric and immunoprecipitation studies. 7G3 was shown to react with the constant (C) region of the T-cell receptor (TCR) delta-chain by the following facts: (1) 7G3 immunoprecipitated full-length TCR delta-chain protein fused with glutathione S-transferase (GST) produced by Esherichia coli and (2) 7G3 reacted with TCR delta-chain expressing Cos-7 cells transfected with either full-length or N-terminal deleted mutant cDNA, but did not react with Cos-7 cells transfected with C-terminal deleted mutant TCR delta-chain cDNA. All three mAbs produced high-quality immunostaining results on frozen sections, revealing a distinct distribution of gammadelta T-cells and CD8(+) cells. This report precisely characterizes mAbs against porcine TCR for the first time, facilitating molecular biological investigations of the porcine immune system.

Amino Acid Sequence↗
PubMed2005

Gene transfer of bFGF to recipient bed improves survival of ischemic skin flap.

BACKGROUND: The recipient bed is a promising target of angiogenic therapy to treat ischemic skin flaps. We delivered basic fibroblast growth factor (bFGF) gene to the recipient bed by a plasmid-based method with electroporation, and assessed the effects on flap viability in a rat dorsal skin flap model. METHODS: A 25 x 90 mm(2) axial skin flap was elevated on the back of male Sprague-Dawley rats. Two days before flap elevation, an expression plasmid vector containing the bFGF gene with the signal sequence was injected into the dorsal muscles beneath the skin flap, and then electroporation was delivered (FGF-E(+) group). As control, rats were injected with a plasmid vector containing LacZ gene (LacZ-E(+) group), instead of bFGF gene. Other groups of animals received plasmid vector containing bFGF (FGF-E(-) group) or LacZ (LacZ-E(-) group) gene without electroporation. Seven days later, the area of necrosis and neovascularisation of the skin flap were evaluated. RESULTS: The bFGF gene was successfully transferred to the dorsal muscles, and bFGF was expressed in muscle tissue. The area of flap necrosis (%) in the FGF-E(+) group (21.7+/-5.3%) was significantly smaller than that in the LacZ-E(+) (28.3+/-4.1%), FGF-E(-) (29.7+/-3.3%), and LacZ-E(-) (28.1+/-2.5%) groups. Postmortem angiograms and histological analyses showed that vascularisation in the distal part of the skin flap was significantly increased in the FGF-E(+) group compared with the other groups. CONCLUSION: These findings suggested that gene delivery of bFGF to the recipient bed muscles enhanced vascularity and viability of an ischemic skin flap, and that plasmid-based gene delivery with electroporation was a suitable delivery method.

Animals↗
PubMed2004

Imaging of all dangling bonds and their potential on the Ge/Si105 surface by noncontact atomic force microscopy.

High-resolution noncontact atomic force microscope (AFM) images were successfully taken on the Ge105-(1 x 2) structure formed on the Si105 substrate and revealed all dangling bonds of the surface regardless of their electronic situation, surpassing scanning tunneling microscopy, whose images strongly deviated from the atomic structure by the electronic states involved. An atomically resolved electrostatic potential profile by a Kelvin-probe method with AFM shows potential variations among the dangling bond states, directly observing a charge transfer between them. These results clearly demonstrate that high-resolution noncontact AFM with a Kelvin-probe method is an ideal tool for analysis of atomic structures and electronic properties of surfaces.

Journal Article↗
PubMed2004

Use of diffusion-weighted magnetic resonance imaging in empyema after cranioplasty.

External decompression can be an effective treatment for acute intracranial hypertension, but the cranial defect must be repaired. The most serious complication of cranioplasty is late infection. Confusing an empyema that occurs after cranioplasty with a fluid collection (haematoma or liquor) can have catastrophic consequences, such as the development of cerebritis. The goal of this study was to assess the ability of diffusion-weighted (DW) magnetic resonance imaging (MRI) to diagnose empyema after cranioplasty. DW MRI and apparent diffusion coefficient (ADC) maps were studied in six patients with surgically verified empyema after cranioplasty. The findings were compared with those in five patients who had surgically verified haematoma or liquorrhoea. In the patients with empyema, the lesion was hyperintense, whereas the fluid collections (haematoma and liquorrhoea) were visualized as hypointense lesions. The ADC maps showed that empyema had a significantly lower intensity than the fluid collections (haematoma or liquorrhoea). DW MRI can be used to identify empyema after cranioplasty and can help to differentiate it from other fluid collections. Hence, this is a useful additional imaging modality for the diagnosis of empyema after cranioplasty.

Adolescent↗
PubMed2003

Molecular cloning and chromosomal assignment to SSC12p13-->p11 of swine chemokine receptor CCR7.

We cloned a gene encoding the swine chemokine (C-C motif) receptor 7 (CCR7) and clarified its genomic structure and chromosomal assignment. The ORF and deduced amino-acid sequence were highly conserved with human and mouse CCR7. The swine CCR7 gene was mapped to SSC12p13-->p11 by FISH analysis. Stimulation of swine peripheral blood mononuclear cells by IL-12 and IL-18, considered potent inducers of Th1 cells from analyses in humans and mice, downregulated the expression of CCR7. This is the first report of the molecular cloning, chromosomal assignment and characterization of a chemokine receptor in swine.

Amino Acid Sequence↗
PubMed2002

A useful approach to the differential diagnosis of small polypoid lesions of the gallbladder, utilizing an endoscopic ultrasound scoring system.

BACKGROUND AND STUDY AIMS: The purpose of this study was to assess the accuracy of endoscopic ultrasonography (EUS) in making a differential diagnosis of small (< or = 20 mm in diameter) polypoid lesions of the gallbladder, and to construct an EUS scoring system. PATIENTS AND METHODS: The EUS findings were retrospectively analyzed in 70 surgical cases of small polypoid lesions classified into two groups: neoplastic (adenocarcinoma in 11, and adenoma in 7), and non-neoplastic (cholesterol polyp in 44, inflammatory polyp in 7 and fibrous polyp in 1). The EUS variables were the maximum diameter and height/width ratio of the largest polyps, echo level, internal echo pattern, surface patterns, number and shape of polyps, presence of hyperechoic spotting, complication of gallbladder stones. The EUS data were used for the construction of an EUS scoring system to ascertain the risk of neoplasia. RESULTS: Three EUS variables, i. e. tumor maximum size, internal echo pattern, and hyperechoic spotting were statistically significant according to multivariate analysis using stepwise logistic regression models (P < 0.01, P < 0.05, and P < 0.01, respectively). The total EUS score based on the coefficient of multivariate analysis was as follows: (maximum diameter in mm) + (internal echo pattern score; where heterogeneous = 4, homogeneous = 0) + (hyperechoic spot[s] score; where presence = - 5, absence = 0). According to our EUS scoring system, the sensitivity, specificity, and accuracy for the risk of neoplastic polyps with scores of 12 or higher were 77.8 %, 82.7 % and 82.9 %, respectively. CONCLUSIONS: The EUS scoring system will be a useful means of differentiating between neoplastic and non-neoplastic polyps of the gallbladder.

Adenocarcinoma↗
PubMed2001

Effects of low-level occupational exposure to styrene on color vision: dose relation with a urinary metabolite.

To investigate the threshold effects of chronic low-level occupational exposure to styrene on color vision, we examined color discrimination in 105 male workers exposed to styrene (mean age 37.7 years; mean length of exposure 6.2 years; mean urinary concentration of mandelic acid 0.21 g/L) and in 117 referents (mean age 37.7 years). We also assessed the effects of styrene by examination of the nature of the relation between disorders of nervous function and age, alcohol consumption, and other variables. A standardized questionnaire was adopted to collect information about work history, occupational or nonoccupational solvent exposure, alcohol consumption, and drug use. Color vision was evaluated by the Lanthony desaturated panel D-15 test. The results of the test were expressed as the color confusion index (CCI). There was a dose-dependent relationship between the urinary concentration of mandelic acid and color vision loss. The CCIs of the subgroups whose urinary mandelic acid levels were 0.1-0.2 and >0.2 g/L were significantly higher than those of each referent group (P<0.05 and P<0.01, respectively), but not in the subgroup whose urinary mandelic acid level was lower than 0.1 g/L. Our study suggests that a low level of styrene, presumably 0.1-0.2 g/L, involves the risk of inducing adverse effects on color vision. After confounding factors were adjusted for, the urinary mandelic acid level had a significant positive relationship with color vision.

Adult↗
PubMed2001

Range of motion physiotherapy reduces the force deficit in antagonists to denervated rat muscles.

BACKGROUND: We used a rat hindlimb model of tibial nerve transection to determine if a loss of mechanical function exists in innervated antagonists compared with denervated muscles. We tested two hypotheses: (1) denervation of the rat ankle plantar flexors results in decreased force production of the ankle dorsiflexors, and (2) daily passive ankle range of motion (ROM) physiotherapy prevents or reduces the force deficit. METHODS: Adult Lewis rats were assigned to one of three groups: (1) a sham (S) group, in which the tibial nerve was exposed but not transected; (2) a no rehabilitation (NR) group, in which a 2-cm segment of tibial nerve was excised at midthigh to denervate the ankle plantar flexors; or (3) a rehabilitation (R) group, in which a 2-cm segment of tibial nerve was excised and the animals were subjected to ankle passive ROM physiotherapy for two 5-min sessions each day. After 14 days, maximum isometric tetanic force (F(0)) and specific force (sF(0)) were measured in the extensor digitorum longus (EDL) muscle, an ankle dorsiflexor. RESULTS: Compared with those from animals in the S group, EDL muscles from animals in the NR group demonstrated a 22% decrease in both F(0) and sF(0). In the EDL from animals in the R group, daily passive ROM physiotherapy diminished the deficit in F(0) but not in sF(0). CONCLUSIONS: These data support the hypotheses that nerve injuries result in impaired mechanical function in the innervated antagonists to denervated muscles and that passive ROM physiotherapy can improve force production in these muscles.

Animals↗
PubMed2001

Novel mode of processing and secretion of connective tissue growth factor/ecogenin (CTGF/Hcs24) in chondrocytic HCS-2/8 cells.

The synthesis, processing, and secretion of human connective tissue growth factor (CTGF/Hcs24) in a human chondrocytic cell line, HCS-2/8, were analyzed immunochemically. By metabolic pulse-labeling, chasing, and subsequent immunoprecipitation analyses, active synthesis of CTGF was observed not only in growing HCS-2/8 cells, but also in confluent cells. However, secretion and processing of CTGF were found to be regulated differentially, depending upon the growth status. During phases of growth, HCS-2/8 cells released CTGF molecules immediately without sequestering them within the cell layer. In contrast, after the cells reached confluence, the secretion slowed, resulting in an accumulation of CTGF in the cells or extracellular matrices (ECMs). Also, in confluent cell layers, a 10 kDa protein that was reactive to an anti-CTGF serum was observed. This CTGF-related small protein was not detected immediately after labeling, but gradually appeared within 6 h after chase, which suggests its entity as a processed subfragment of CTGF. Surprisingly, the 10 kDa protein was stable even 48 h after synthesis, and was not released by ECM digestion, suggesting an intracellular maintenance and function. Taken together, the behavior of CTGF in HCS-2/8 cells is remarkably different from that reported in fibroblasts, which may represent unique roles for CTGF in the growth and differentiation of chondrocytes.

Amino Acid Sequence↗
PubMed2001

Amino acid sequence of Kalinowaski's Tinamou (Nothoprocta kalinowskii) hemoglobin and the rate of evolution of bird alphaD-globin.

Two hemoglobin components are recognized in erythrocytes of the adult Tinamou. We determined the amino acid sequences of Tinamou alphaD-, alphaA-, and beta-globins from intact globin chains and several chemically cleaved fragments. A remarkable feature of Tinamou hemoglobin was a deletion in the alphaD-globin chain. This has not been reported in the literature, except in pigeon embryonic alphaD-globin. The amino acid sequences of Tinamou globin were highly similar to those of Ostrich and Rhea hemoglobin. Comparison between Tinamou, Ostrich, and Rhea that suggested the evolution speed of globin, alphaD = alphaA > beta, was related with the early appearance birds. The important residues in Tinamou hemoglobin as the heme contact and oxygen binding regions were highly conserved in other species.

Amino Acid Sequence↗
PubMed2001

Cell-type-specific trans-activation of herpes simplex virus thymidine kinase promoter by the human T-cell leukemia virus type I Tax protein.

The human T-cell leukemia virus type I Tax protein (HTLV-I Tax) is known as a trans-activating factor for a variety of genes, including those of cytokines. Here, we show that Tax is capable of activating the herpes simplex virus thymidine kinase (HSV-TK) promoter in certain mammalian cell lines. In murine NIH 3T3 fibroblasts and human HeLa cells, trans-activation by Tax was remarkably strong, whereas in human chondrocytic HCS-2/8 and monkey kidney Cos-7 cells, the responsiveness of the TK promoter to Tax was poor. Deletion analysis revealed that one of the two previously described Sp1 sites is required for the Tax responsiveness, whereas the CTF binding site is not. The results suggest possible interactions between the oncogenic Tax protein and the viral TK in coinfected cells in vivo. Care should be taken in the context of HTLV-I research, as the HSV-TK promoter has been widely used in molecular biology and gene therapeutics.

3T3 Cells↗
PubMed2001

Regulatory mechanism of human connective tissue growth factor (CTGF/Hcs24) gene expression in a human chondrocytic cell line, HCS-2/8.

CTGF/Hcs24 is a multi-functional growth factor that potentiates either the growth or differentiation of mesenchymal cells, according to the biological conditions. Among various functional aspects of CTGF/Hcs24, it is especially notable that CTGF/Hcs24 may promote endochondral ossification in growth cartilage through all stages, and it is highly expressed in a human chondrosarcoma-derived chondrocytic cell line (HCS-2/8). In this study, to clarify the regulatory mechanism of CTGF/Hcs24 gene expression in chondrocytes, we analyzed the transcriptional activity of the CTGF/Hcs24 promoter and the effect of the CTGF/Hcs24 3'-untranslated region (3'-UTR) on gene expression in HCS-2/8 by means of an established DNA transfection and luciferase reporter gene assay system. As a result, the luciferase activity of the CTGF/Hcs24 promoter was found to be remarkably high in HCS-2/8. The 3'-UTR of the CTGF/Hcs24 gene strongly repressed the luciferase activity in HCS-2/8, when it was linked to the downstream of the luciferase reporter gene, suggesting its functionality also in chondrocytic cells. Deletion analysis of the CTGF/Hcs24 promoter clarified a major segment responsible for the enhanced CTGF/Hcs24 promoter activity in HCS-2/8. The TGF-beta response element in the DNA segment was active in HCS-2/8, and point mutations in the element moderately decreased the highly maintained promoter activity with total loss of TGF-beta responsiveness. These results indicate that the strong expression of the CTGF/Hcs24 gene in HCS-2/8 was mainly caused by high transcriptional activity of the CTGF/Hcs24 promoter, and that the TGF-beta response element is one of the critical elements that support the high transcription activity.

3' Untranslated Regions↗
PubMed2001

Surgical repair for congenital macrostomia: vermilion square flap method.

Congenital macrostomia (transverse facial cleft) is a relatively rare anomaly. Surgical methods used to correct this anomaly include commissuroplasty, muscle-plasty of the orbicularis oris, and closure of the cleft cheek. The authors report a new vermilion square flap surgical technique that combines a lower lip mucocutaneous vermilion border flap with a lazy W-plasty to ensure a natural commissure and cheek skin closure. This technique was used in 8 patients with satisfactory results.

Abnormalities, Multiple↗
PubMed2001

Isolation and characterization of enterocin SE-K4 produced by thermophilic enterococci, Enterococcus faecalis K-4.

Enterococcus sp. K-4, with a bacteriocin-like activity against E. faecium, was isolated from grass silage in Thailand. Morphological, physiological, and phylogenetic studies clearly identified strain K-4 as a strain of E. faecalis. Strain K-4 produced a maximal amount of bacteriocin at 43-45 degrees C. We purified, for the first time, the bacteriocin produced at high temperature by E. faecalis to homogeneity, using adsorption on cells of the producer strain and reversed-phase liquid chromatography. The bacteriocin, designated enterocin SE-K4, is a peptide of about 5 kDa as measured by SDS-PAGE, and Mass spectrometry analysis found the molecular mass of 5356.2, which is in good agreement. The amino acid sequencing of the N-terminal end of enterocin SE-K4 showed apparent sequence similarity to class IIa bacteriocins. Enterocin SE-K4 was active against E. faecium, E. faecalis, Bacillus subtilis, Clostridium beijerinckii, and Listeria monocytogenes. Enterocin SE-K4 is very heat stable.

Amino Acid Sequence↗