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Biomedical subjects

M Ueda

Publications and source records attributed to M Ueda.

At least 55 records · Page 3Linked to original sources
PubMed2005

Alterations of p53, cyclin D1 and pRB expression in the carcinogenesis of esophageal squamous cell carcinoma.

Many molecular alterations occur in esophageal carcinogenesis; however, little is known about the molecular genetic events responsible for the development of carcinoma. We investigated the expression of ki67, p53, cyclin D1 and pRB in 105 biopsy specimens using immunohistochemistry from iodine unstained lesions as indicators of carcinogenesis of the esophagus. Also, the genetic alternation of esophageal dysplasia from patients with accompanying esophageal squamous cell carcinoma (ESCC) was examined to study the evidence for field carcinogenesis in the esophagus. The expression of p53, cyclin D1 and pRB was detected in 31, 0 and 51.7% respectively of mild dysplasia; 40, 0 and 70% of moderate dysplasia; 40, 20 and 70% of severe dysplasia; and 48, 32 and 80% of carcinoma specimens. p53 expression was significantly increased in mild dysplasia, whereas cyclin D1 and pRB expression were significantly increased in carcinoma as compared to both normal epithelium and esophagitis. The ki67 LI and the rate of p53 expression were significantly higher in dysplasia with ESCC than in dysplasia without ESCC. Ki67, p53, cyclin D1 and pRB expression may be useful biomarkers for assessing the risk of developing esophageal cancer. Dysplasia observed at screening for secondary lesions has a highly malignant potential and careful follow-up studies are required.

Carcinoma, Squamous Cell↗
PubMed2004

Multiphoton transitions in a macroscopic quantum two-state system.

We have observed multiphoton transitions between two macroscopic quantum-mechanical superposition states formed by two opposite circulating currents in a superconducting loop with three Josephson junctions. Resonant peaks and dips of up to three-photon transitions were observed in spectroscopic measurements when the system was irradiated with a strong rf-photon field. The widths of the multiphoton absorption dips are shown to scale with the Bessel functions in agreement with theoretical predictions derived from the Bloch equation or from a spin-boson model.

Journal Article↗
PubMed2004

Near-infrared spectrophotoscopy of finger venules in assessment of autonomic dysfunction.

The authors evaluated morphologic changes in the venules of the finger using near-infrared spectrophotoscopy in patients with autonomic dysfunction, such as familial amyloidotic polyneuropathy and multiple-system atrophy. Abnormalities of the venules, such as tortuosity, irregular venous caliber, and microaneurysm-like change, and a linear negative correlation between the degree of orthostatic hypotension and the degree of vasoconstriction of the venules were observed.

Adult↗
PubMed2004

Heterologous expression of metabotropic glutamate receptor subtype 1 in Saccharomyces cerevisiae.

The upstream region of the isocitrate lyase gene (UPR-ICL) from the n-alkane-utilizing yeast Candida tropicalis serves as a useful promoter of gene expression in the yeast Saccharomyces cerevisiae. The production of rat metabotropic glutamate receptor 1alpha (mGluR1alpha), which belongs to the G-protein-coupled receptor (GPCR) family, was tested under the control of UPR-ICL. Expression of mGluR1alpha was found in recombinant clones and enhanced by replacing the signal sequence of mGluR1alpha with the corresponding region of the alpha-factor receptor (Ste2), which is a GPCR found in S. cerevisiae. Moreover, the membrane fraction from a recombinant clone associated with Vesl-1S/Homer-1a protein binds the mGluR1alpha in rat cerebellum. These results suggest that the UPR-ICL-controlled gene expression system is useful for heterologous GPCRs in S. cerevisiae.

Animals↗
PubMed2004

Yeast cell-surface display--applications of molecular display.

In a cell-surface engineering system established using the yeast Saccharomyces cerevisiae, novel, so-called arming yeasts are constructed that are armed with biocatalysts in the form of enzymes, functional proteins, antibodies, and combinatorial protein libraries. Among the many advantages of the system, in which proteins are genetically displayed on the cell surface, are easy reproduction of the displayed biocatalysts and easy separation of product from catalyst. As proteins and peptides of various kinds can be displayed on the yeast cell surface, the system is expected to allow the preparation of tailor-made functional proteins. With its ability to express many of the functional proteins necessary for post-translational modification and in a range of different sizes, the yeast-based molecular display system appears uniquely useful among the various display systems so far developed. Capable of conferring novel additional abilities upon living cells, cell-surface engineering heralds a new era of combinatorial bioengineering in the field of biotechnology. This mini-review describes molecular display using yeast and its various applications.

Agglutinins↗
PubMed2004

Experimental study of mechanical analysis in mandibular lengthening. Application of strain gauge measurement.

In distraction osteogenesis, the assessment of new bone formation and the decision of when to remove the distraction device are very important from clinical viewpoint. The purpose of this study was to measure bone stiffness using a strain gauge during and after mandibular lengthening, and to compare the results with those from radiographic and histological examinations. Twelve adult mongrel dogs served as the experimental subjects. An external distraction device was connected to the mandible, and distraction was started 7 days after operation and continued for 10 consecutive days. The animals underwent strain gauge measurement and radiographic examination of the mandible at the completion of distraction and every 2 weeks until the end of the consolidation period. The animals were then sacrificed at 2, 4, 6, 8, 10, and 12 weeks after completion of the distraction for histologic examinations. There was correlation between the amount of decrease in strain, increase in ratio of radiopacity, and newly formed bone in the distracted area.

Animals↗
PubMed2004

A new technique of microvascular suturing: the chopstick rest technique.

With the conventional techniques of tying knots during microvascular anastomosis or neural suturing, time may be lost due to various reasons. The loose end of the suture often falls down into the operative field and gets stuck to the surrounding tissues. In the process of retrieving the suture, the surrounding tissues can be picked up together with the suture. When the posterior wall technique [Br J Plast Surg 34 (1981) 47, Plast Reconstr Surg 69 (1982) 139, Microsurgery 8 (1987) 22, J Reconstr Microsurg 15 (1999) 321] is used, the loose end of the suture may be stuck to the backside of the vessel and may be hard to grab. In order to avoid those problems, a new way of tying a microsuture was developed. By avoiding contact of the loose end of the suture to the surrounding tissue at any point during tying, the microvascular anastomosis can be performed quicker and more efficiently.

Humans↗
PubMed2004

Usefulness of artificial liver support for pretransplant patients with fulminant hepatic failure.

This study assessed the usefulness of artificial liver support (ALS) for pretransplant patients with fulminant hepatic failure (FHF). Five patients (age 14 to 52 years, 3 men and 2 women) with FHF who were being prepared for living donor liver transplantation (LDLTx) were enrolled in this study. ALS included plasma exchange, using 40 to 50 units of fresh frozen plasma per session, and high-flow hemodiafiltration, using a high-performance polysulfone membrane. Variables such as circulatory and respiratory function, coma grade, and neurologic disorders were evaluated. Although systolic and diastolic blood pressures showed no statistical differences between pre-ALS and post-ALS, the difference in heart rates was statistically significant. After ALS initiation in the pre-LDLTx period, one of the three patients who needed mechanical ventilation was weaned from it. After LDLTx, all patients recovered neurologically; no neurologic disorder was observed. These results suggested that ALS could predict neurologic status after LDLTx. The difference in coma grades also achieved statistical significance. Our study indicates that short-term ALS is useful for improving circulatory and respiratory function prior to liver transplantation, as well as for predicting posttransplantation neurologic status. Although some patients recover by ALS alone, the survival rate of ALS-only patients is less than 50%. ALS prolongs intensive treatment, thus increasing both the risk of infection and the medical costs. Further investigation to determine a precise marker for liver regeneration will be needed to establish a consensus on the indications for long-term ALS. We conclude that ALS is useful to improve circulatory and respiratory functions among pretransplant patients, and to predict neurologic status after LDLTx.

Adolescent↗
PubMed2004

Prevention of hepatitis B virus recurrence after living donor liver transplantation.

The emergence of lamivudine-resistant hepatitis B mutations is a major complication during pretransplantation treatment. The proper time to begin Lamivudine before transplantation is not yet known. Twenty-six patients received preoperative lamivudine treatment followed by combined lamivudine and hepatitis B immunoglobulin after transplantation up to December 2002. The length of preoperative lamivudine treatment ranged from 13 to 200 days (mean, 52 +/- 37 days). Hepatitis B virus-DNA was positive in 22 of 26 (84.6%) patients before preoperative lamivudine prophylaxis and persistently positive among only 4 of 22 patients (18%) who at transplantation did not show a viral mutation. In all patients, hepatitis B virus-DNA became negative immediately after transplantation. At a median follow-up of 34 months, neither a hepatitis B recurrence nor a mutation had occurred in any patient. The ability to schedule the proper time for preoperative lamivudine prophylaxis is an advantage of living donor liver transplantation.

Antiviral Agents↗
PubMed2004

Targeted conversion of the transthyretin gene in vitro and in vivo.

Familial amyloidotic polyneuropathy (FAP) is the common form of hereditary generalized amyloidosis and is characterized by the accumulation of amyloid fibrils in the peripheral nerves and other organs. Liver transplantation has been utilized as a therapy for FAP, because the variant transthyretin (TTR) is predominantly synthesized by the liver, but this therapy is associated with several problems. Thus, we need to develop a new treatment that prevents the production of the variant TTR in the liver. In this study, we used HepG2 cells to show in vitro conversion of the TTR gene by single-stranded oligonucleotides (SSOs), embedded in atelocollagen, designed to promote endogenous repair of genomic DNA. For the in vivo portion of the study, we used liver from transgenic mice whose intrinsic wild-type TTR gene was replaced by the murine TTR Val30Met gene. The level of gene conversion was determined by real-time RCR combined with mutant-allele-specific amplification. Our results indicated that the level of gene conversion was approximately 11 and 9% of the total TTR gene in HepG2 cells and liver from transgenic mice, respectively. Gene therapy via this method may therefore be a promising alternative to liver transplantation for treatment of FAP.

Amyloid Neuropathies↗
PubMed2004

Transplantation of cultured salivary gland cells into an atrophic salivary gland.

Patients with dry mouth have been treated with salivary substitutes and/or medications such as pilocarpine or cevimeline hydrochloride. These treatments temporarily relieve their symptoms and induce salivation from residual tissue. However, no treatment is available for the purpose of regenerating an atrophic gland. In this study, the feasibility of a cell transplantation therapy for the atrophic submandibular glands was investigated in rats. Further, the potential of cell differentiation into a useful phenotype was assessed by immunohistochemistry together with cell tracking with the fluorescent dye PKH 26. Rat submandibular glands were excised, and the salivary gland epithelial cells were cultured for 3 weeks with 3T3 cells as a feeder layer. Ductal ligation of the submandibular gland was employed to generate an atrophic gland. One week after the operation, the ligation was removed, and the cultured cells labeled with PKH 26 were injected into the atrophic submandibular glands. As a control, the cultured cells were also injected into normal submandibular glands. Two weeks after cell transplantation, the transplanted cells were detectable in both the experimental and control groups. The cells were clustered in the connective tissue between the lobules. Four weeks after transplantation, the labeled cells were detectable in the experimental group but not in the control group. In the atrophic glands, the scattered transplanted cells were observed over a broad area of the gland but localized mainly around the acini and ductal region. Immunostaining results showed a possible involvement of the transplanted cells in ductal regeneration, while neither myoepithelial nor acinar differentiations were observed within the 4 weeks since transplantation. This study demonstrated that cell transplantation to the salivary gland is feasible, and that the transplanted cells were selectively attracted to and remained in the damaged area without affecting normal tissue.

3T3 Cells↗
PubMed2003

Bioadsorption of cadmium ion by cell surface-engineered yeasts displaying metallothionein and hexa-His.

The Cd(2+)-chelating abilities of yeast metallothionein (YMT) and hexa-His displayed on the yeast-cell surface were compared. Display of YMT and hexa-His by alpha-agglutinin-based cell-surface engineering was confirmed by immunofluorescent labeling. Surface-engineered yeast cells with YMT and hexa-His fused in tandem showed superior cell-surface adsorption and recovery of Cd2+ under EDTA treatment on the cell surface than hexa-His-displaying cells. YMT was demonstrated to be more effective than hexa-His for the adsorption of Cd2+. Yeast cells displaying YMT and/or hexa-His exhibited a higher potential for the adsorption of Cd2+ than Escherichia coli cells displaying these molecules. In order to investigate the effect of the displayed YMT and hexa-His on sensitivity to toxic Cd2+, growth in Cd(2+)-containing liquid medium was monitored. Unlike hexa-His-displaying cells, cells displaying YMT and hexa-His fused in tandem induced resistance to Cd2+ through active and enhanced adsorption of toxic Cd2+. These results indicate that YMT-displaying yeast cells are a unique bioadsorbent with a functional chelating ability superior to that of E. coli.

Adsorption↗
PubMed2003

UV-induced skin damage.

Solar radiation induces acute and chronic reactions in human and animal skin. Chronic repeated exposures are the primary cause of benign and malignant skin tumors, including malignant melanoma. Among types of solar radiation, ultraviolet B (290-320 nm) radiation is highly mutagenic and carcinogenic in animal experiments compared to ultraviolet A (320-400 nm) radiation. Epidemiological studies suggest that solar UV radiation is responsible for skin tumor development via gene mutations and immunosuppression, and possibly for photoaging. In this review, recent understanding of DNA damage caused by direct UV radiation and by indirect stress via reactive oxygen species (ROS) and DNA repair mechanisms, particularly nucleotide excision repair of human cells, are discussed. In addition, mutations induced by solar UV radiation in p53, ras and patched genes of non-melanoma skin cancer cells, and the role of ROS as both a promoter in UV-carcinogenesis and an inducer of UV-apoptosis, are described based primarily on the findings reported during the last decade. Furthermore, the effect of UV on immunological reaction in the skin is discussed. Finally, possible prevention of UV-induced skin cancer by feeding or topical use of antioxidants, such as polyphenols, vitamin C, and vitamin E, is discussed.

Animals↗
PubMed2003

A chitinase with high activity toward partially N-acetylated chitosan from a new, moderately thermophilic, chitin-degrading bacterium, Ralstonia sp. A-471.

A moderately thermophilic bacterium, strain A-471, capable of degrading chitin was isolated from a composting system of chitin-containing waste. Analysis of the 16S rDNA sequence revealed that the bacterium belongs to the genus Ralstonia. A thermostable chitinase A ( Ra-ChiA) was purified from culture fluid of the bacterium grown in colloidal chitin medium. Purification of the enzyme was achieved mainly by exploiting its binding to the colloidal chitin. The molecular mass of the enzyme was estimated to be 70 kDa and the isoelectric point approximately 4.7. N-terminal amino acid sequencing revealed a sequence of ADPYLKVAYYP, which had high homology (66% identity) with that of chitinase A1 from Bacillus circulans WL-12. The pH and temperature optima were determined to be 5.0 and 70 degrees C, respectively. The enzyme was classified as a retaining glycosyl hydrolase and was most active against partially N-acetylated chitosans. Its activities towards the partially N-acetylated chitosans, i.e. chitosan 7B, chitosan 8B, and chitosan 9B, were about 11-fold, 9-fold, and 5-fold higher than towards colloidal chitin, respectively. Ra-ChiA cleaved (GlcNAc)6 almost exclusively into (GlcNAc)2. Activation of Ra-ChiA was observed by the addition of 1 mM Cu2+, Mn2+, Ca2+, or Mg2+. Degradation of the partially N-acetylated chitosan produced oligosaccharides with a degree of polymerization ranging from 1-8; these are products that offer potential application for functional oligosaccharide production.

Chitin↗
PubMed2003

Display of a functional hetero-oligomeric catalytic antibody on the yeast cell surface.

A functional hetero-oligomeric protein was, for the first time, displayed on the yeast cell surface. A hetero-oligomeric Fab fragment of the catalytic antibody 6D9 can hydrolyze a non-bioactive chloramphenicol monoester derivative to produce chloramphenicol. The gene encoding the light chain of the Fab fragment of 6D9 was expressed with the tandemly-linked C-terminal half of alpha-agglutinin. At the same time, the gene encoding the Fd fragment of the heavy chain of the Fab fragment was expressed as a secretion protein. The combined Fab fragment displayed and associated on the yeast cell surface had an intermolecular disulfide linkage between the light and heavy chains. This protein fragment catalyzed the hydrolysis of a chloramphenicol monoester derivative and exhibited high stability in binding with a transition-state analog (TSA). The catalytic reaction was also inhibited by the TSA. The successful display of a functional hetero-oligomeric catalytic antibody provides a useful model for the display of hetero-oligomeric proteins and enzymes.

Antibodies, Catalytic↗
PubMed2003

Structure-function study of the amino-terminal stretch of the catalase subunit molecule in oligomerization, heme binding, and activity expression.

Analysis of the protein structure of bovine liver catalase suggested that the N-terminal region containing two alpha-helices may function as a linker binding to another subunit. The number of amino-acid residues in catalase from the n-alkane-assimilating yeast Candida tropicalis (CTC) is the lowest of any eukaryotic catalase molecule hitherto investigated, and only one helix, corresponding to the helix alpha2 in bovine liver catalase, is estimated to be present in the same region. In the present study, N-terminal-deleted mutants of CTC were characterized to evaluate the role of the alpha-helix structure in the N-terminal region. CTCDelta1-4 and CTCDelta1-24, whose N-terminal regions were shortened by four and 24 amino-acid residues, respectively, showed an 80% decrease in specific activity compared to wild-type CTC in spite of containing the same amount of heme as in the wild-type. Polyacrylamide gel electrophoresis under nondenaturing conditions revealed that the mutants contained large amounts of oligomeric forms with molecular masses less than 220 kDa (tetramer assembly). Although the smaller oligomers were found to be bound with heme, only the tetramer exhibited catalase activity in activity staining on nondenaturing gel. CTCDelta1-49, a mutant with deletion of the N-terminal 49 amino-acid residues which contain the conserved helix alpha2, showed no catalase activity and no heme binding. However, the CD spectrum profiles of CTCDelta1-49, CTCDelta1-4, and CTCDelta1-24 indicated that these mutant subunits could attain secondary conformations similar to that of wild-type CTC, regardless of their binding with heme. From these results, it was concluded that the N-terminal stretch of catalase is significant for complete assembly into active tetramer and that the conserved helix alpha2, although it has little effect on the formation of the subunit secondary structure, is indispensable not only in assembling tetramer but also in binding heme.

Amino Acid Sequence↗