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M Gotoh

Publications and source records attributed to M Gotoh.

At least 199 records · Page 11Linked to original sources
PubMed1995

A new approach to determine the effect of mismatches on kinetic parameters in DNA hybridization using an optical biosensor.

We have demonstrated a simple yet direct method for determining the kinetic parameters in DNA-DNA interactions using biosensor technology based on the surface plasmon resonance phenomenon; a technique that does not require complex DNA labeling. To determine the effect of mismatches on the kinetics involved in DNA-DNA interactions, DNA hybridization kinetics were monitored in real time using synthetic oligonucleotides less than 20 bases in length which contained either a complementary sequence or mismatched bases. Upon analysis of the kinetic parameters obtained in oligonucleotide hybridization, we found that they were significantly affected by the presence of mismatches as well as by their number and location in a DNA duplex. In addition, the presented biosensor method is sensitive enough to detect kinetic effects caused by the presence of a single-mismatched base pair. Our findings strongly suggest that analysis of kinetic parameters involved in DNA-DNA interactions is advantageous for detecting the presence of mismatch base pairs in a DNA duplex.

Base Sequence↗
PubMed1995

Isolation and sequence analysis of human cadherin-6 complementary DNA for the full coding sequence and its expression in human carcinoma cells.

The expression pattern of E- and P-cadherin in human carcinomas has been reported by many laboratories. However, little is known about the involvement of other cadherin types in human carcinomas. cDNA clones for a cadherin molecule were isolated from a cDNA library of human hepatocellular carcinoma cells which lacked E- and P-cadherin expression but exhibited cell aggregation activity mediated by an unknown cadherin, and they were subjected to sequence analysis. The overlapped clones covered 4315 nucleotides and were found to encode a typical cadherin molecule consisting of 790 amino acids. Since the deduced amino acid sequence was identical to a partially available human cadherin-6 sequence except for two amino acid residues, the clones were considered to be human cadherin-6 cDNAs encoding the entire open reading frame. The deduced amino acid sequence also showed extremely high homology with recently reported rat K-cadherin, 97% for the putative mature protein, suggesting that cadherin-6 is the human counterpart of rat K-cadherin. Expression of cadherin-6 in various human normal tissues and carcinoma cells was examined by Northern blot analysis using a specific probe corresponding to the signal and precursor sequence. Among normal tissues examined, brain, cerebellum, and kidney showed strong expression of cadherin-6, whereas lung, pancreas, and gastric mucosa showed weak expression. Transcripts of cadherin-6 were not detected in normal liver, whereas four of six hepatocellular carcinoma cell lines examined expressed cadherin-6 abundantly. As reported for rat K-cadherin, three renal carcinoma cell lines also expressed cadherin-6 strongly. The most interesting finding was obtained for small cell lung carcinoma lines. Among 15 of such cell lines examined, all of 11 cadherin-6-positive lines were classified into the classic type, whereas the negative cell lines were all of the variant type. The present results suggest that besides E- and P-cadherin, other cadherin molecules are expressed in human cancers and are responsible for additional biological properties of the carcinoma cells.

Base Sequence↗
PubMed1995

Circular dichroism of the O-specific polysaccharide of Vibrio cholerae O1 and some related derivatives.

The O-specific polysaccharide (O-SP) of Vibrio cholerae O1 is a homopolymer of alpha-(1 --> 2)-linked 4-amino-4, 6-dideoxy-D-mannopyranose whose amino group is acylated with 3-deoxy-L-glycero-tetronic acid [N-(3-deoxy-L-glycero- tetronyl)-alpha-D-perosamine]. The circular dichroism (CD) of the O-SP as well as of a number of N-acyl (formyl, acetyl, 4-hydroxybutyl, 3-deoxy-L-and D-glycero-tetronyl) derivatives of methyl alpha-glycosides of 4-amino-4,6-dideoxy-D-mannopyranose (methyl alpha-D-perosaminide) has been studied for solutions in water, acetonitrile and 1,1,1-trifluoroethanol. The strong solvent dependence of the sign and intensity of the CD observed for the monosaccharide amides bearing achiral acyl groups is explained by solvent-mediated change of the orientation of the amido group relative to the proximal hydroxyl group at C-3. A change in the population of the nonplanar conformers with a pyramidal arrangement of bonds at the amido nitrogen has also been considered. The effect of solvents upon the CD spectra of compounds bearing chiral N-acyl substituents is less pronounced than that of their counterparts bearing achiral N-acyl substituents. The sign of the CD for the O-SP was found negative in all solvents used. This result is in agreement with the negative sign of the CD of the n --> pi electron transition observed, independent of the solvent, for the monosaccharide derivative containing the L-glycero-3-deoxytetronamido group, and the positive sign found for its D-glycero-counterpart.

Acetonitriles↗
PubMed1995

Synthesis of specifically deoxygenated analogues of the methyl alpha-glycoside of the intracatenary monosaccharide repeating unit of the O-polysaccharide of Vibrio cholerae O:1.

Treatment of methyl alpha-D-perosaminide (1) with gamma-butyrolactone gave the 2'-deoxy analogue of methyl 4,6-dideoxy-4-(3-deoxy-L-glycero-tetronamido)-alpha-D-mannopyranos ide (13), the methyl alpha-glycoside of the intracatenary monosaccharide repeating unit of the O-polysaccharide of Vibrio cholerae O:1. The analogous 4'-deoxy derivative was obtained by hydrogenolysis of a 4'-chlorodeoxy precursor, obtained by chlorination of methyl 2,3-di-O-benzyl-4-(2-O-benzyl-3-deoxy-L-glycero-tetronamido)-4,6-d ideoxy-alpha- D-mannopyranoside with methanesulfonyl chloride in DMF. To obtain the 3-deoxy analogue of 13, methyl 4-amino-2-O-benzyl-4,6-dideoxy-3-O-p-methoxy-benzyl-alpha-D-mannopyranos ide was converted into methyl 2-O-benzyl-4,6-dideoxy-4-(2,4-di-O-benzyl-3-deoxy-L-glycero-tetronami do)- alpha-D-mannopyranoside, which was deoxygenated via the corresponding 3-O-(imidazol-1-ylthiocarbonyl) derivative. Subsequent catalytic debenzylation gave the deoxy compound (24). In an alternative synthesis, which is also generally useful for the preparation of 4-N-acyl-3-deoxy derivatives of 1, methyl 4-azido-4,6-dideoxy-alpha-D-mannopyranoside was converted through a series of transformations into methyl 4-amino-2-O-benzyl-3,4,6-tri-deoxy-alpha-D-mannopyranoside. Subsequent reaction with 2-O-benzyl-3-deoxy-L-glycero-tetronolactone, followed by hydrogenolysis of the formed tetronamido derivative, gave 24.

Deoxy Sugars↗
PubMed1995

Inhibitory activity of anti-beta 2-glycoprotein I antibody on factor Va degradation by activated-protein C and its cofactor protein S.

We investigated the influence of anti-beta 2-glycoprotein I (aGPI), which recently has come to be regarded as anti-cardiolipin antibody (aCL) itself, on factor Va (FVa) degradation by activated protein C/protein S system. We found that aGPI had an inhibitory effect on FVa degradation with beta 2-glycoprotein I-dependency, thus suggesting aGPI/aCL is a highly possible factor as the pathogenesis of thrombosis observed in aGPI/aCL-positive patients.

Animals↗
PubMed1995

Human immunodeficiency virus rather than hepatitis C virus infection is relevant to the development of an anti-cardiolipin antibody.

We have investigated whether or not a relationship exists between anti-cardiolipin antibody (aCL) positivity and human immunodeficiency virus type 1 (HIV) and/or hepatitis C virus (HCV), and we have attempted to clarify which virus has close association with the development of aCL. We found that aCL positivity in HIV-infected patients was significantly higher than in HCV-infected patients. Furthermore, HIV/HCV dual-infected patients exhibited a higher aCL positivity than patients infected by HCV alone. From these results, we conclude that HIV rather than HCV plays an important role in the development of aCL.

Antibodies, Anticardiolipin↗
PubMed1995

Role of micro-chimerism in inducing immunological tolerance by intraportal injection of donor spleen cells in rats.

Recently, we reported that intraportal (IP) injection of donor spleen cells (SPCs) prevented liver allograft rejection. Moreover, we developed a new method using polymerase chain reaction (PCR)-mediated restriction fragment length polymorphism (RFLP) analysis, and demonstrated micro-chimerism (MC) at the DNA level in the spleen 14 days after IP injection. In the present study, the long-term presence of injected allogeneic SPCs was investigated at the cellular level by immunofluorescence staining as well as the DNA level using RFLP analysis. Male ACI (RT1a) rats were used as the donors and Lewis (RT1(1)) rats as the recipients. After DNA preparation from the lymphoid organs, RT1B beta domain 1 region was amplified by PCR, and RFLP analysis was performed with PvuII restriction enzyme. In the immunofluorescence staining, the monoclonal antibody, MN4-91-6, was used to detect the injected donor ACI SPCs in a frozen specimen. We did not detect MC in Lewis rats intravenously injected with 5 x 10(7) ACI SPCs on day 14. On the other hand, stable chimerism in the spleen was observed in intraportally injected rats up to 28 days after injection at not only the DNA level but also the cellular level. No chimerism was detected in other organs (including the thymus, lymph nodes, and liver). In conclusion, the long-term presence of injected allogeneic SPCs in the spleen was demonstrated after IP injection but not after IV injection, and this phenomenon may be one of the mechanisms involved in portal venous immunosuppression.

Animals↗
PubMed1995

A protocol with FK 506 for inducing unresponsiveness to murine islet allografts.

BACKGROUND: The most favorable protocol for transplantation is inducing unresponsiveness before operation by means of nondangerous modalities. This would permit discontinuance of long-term use of immunosuppressants. In this study we developed a potential protocol for inducing unresponsiveness to islet allografts by preoperative donor spleen cell inoculation (DSI) and a single injection of FK 506. METHODS: BALB/c (H-2d) and C57BL/6 (H-2b) mice were used as islet donors and recipients, respectively. The streptozocin-induced diabetic mice that had been given DSI at a dose of 1 x 10(7) or 1 x 10(4) and a single injection of FK 506 (10 mg/kg intramuscularly) at different schedules (on day 1, 3, 5, or 7 relative to DSI on day 0) were subjected to islet allografting on day 10. RESULTS: All islet recipients returned to normoglycemia within a few days with no toxic effect of FK 506 treatment. DSI at a dose of 1 x 10(7) alone led to shortening of the mean survival time to 10.1 +/- 4.1 days, as compared with 13.5 +/- 6.3 days for the untreated animals. In contrast, marked prolongation of graft survival was induced when FK 506 was given on day 3 (> 84 +/- 27.3 days, p < 0.0001) or on day 5 after DSI (> 50.9 +/- 46.0 days, p < 0.05). Five of seven allografts given FK 506 on day 3 and three of seven allografts given FK 506 on day 5 survived indefinitely. Other time schedules of DSI and FK 506 treatment (on day 1 or 7 after DSI) or FK 506 treatment alone had no significant effect on mean survival time. With the same protocol, third-party islet allografts (C3H) were immediately rejected (10.6 +/- 2.6 days). CONCLUSIONS: Prolongation of islet allograft survival was induced by certain doses of DSI and preoperative FK 506 treatment. This modality prevents an adverse effect of FK 506 on grafted islets and can induce unresponsiveness to islet allografts, offering a protocol for successful clinical islet transplantation.

Animals↗
PubMed1995

Molecular cloning of a cell-surface glycoprotein that can potentially discriminate mesothelium from epithelium: its identification as vascular cell adhesion molecule 1.

It has long been a practical problem for surgical pathologists to distinguish mesothelium from epithelium in order to make a positive diagnosis of mesothelioma. In this study, we developed a new monoclonal antibody, designated MS-2761 (IgG1, k), against cultured non-neoplastic mesothelial cells. Immunohistochemistry and slot-blot analysis revealed that this monoclonal antibody reacted with 100% (12/12) of benign and malignant mesothelioma tissues and a mesothelioma cell line, but not with 99% (77/78) of epithelial tumour tissues and 97% (33/34) of epithelial tumour cell lines. A gene encoding the cell-surface antigen defined by this monoclonal antibody was isolated from a mesothelial cell cDNA library constructed with a mammalian cell expression vector through transfection of Cos-7 cells and immunoselection by panning. DNA sequencing and a database search revealed that the gene was identical to vascular cell adhesion molecule 1 (VCAM1, also referred to as INCAM110). The prominent VCAM1 transcript in mesothelium was 3.2 kb in size with seven Ig-like domains, in addition to a minor transcripts with six Ig-like domains. This monoclonal antibody potentially discriminates mesothelium from epithelium and may become a tool for differential diagnosis of mesothelioma.

Animals↗
PubMed1995

Citrus flavone tangeretin inhibits leukaemic HL-60 cell growth partially through induction of apoptosis with less cytotoxicity on normal lymphocytes.

Certain anti-cancer agents are known to induce apoptosis in human tumour cells. However, these agents are intrinsically cytotoxic against cells of normal tissue origin, including myelocytes and immunocytes. Here we show that a naturally occurring flavone of citrus origin, tangeretin (5,6,7,8,4'-pentamethoxyflavone), induces apoptosis in human promyelocytic leukaemia HL-60 cells, whereas the flavone showed no cytotoxicity against human peripheral blood mononuclear cells (PBMCs). The growth of HL-60 cells in vitro assessed by [3H]thymidine incorporation or tetrazolium crystal formation was strongly suppressed in the presence of tangeretin; the IC50 values range between 0.062 and 0.173 microM. Apoptosis of HL-60 cells, assessed by cell morphology and DNA fragmentation, was demonstrated in the presence of > 2.7 microM tangeretin. Flow cytometric analysis of tangeretin-treated HL-60 cells also demonstrated apoptotic cells with low DNA content and showed a decrease of G1 cells and a concomitant increase of S and/or G2/M cells. Apoptosis was evident after 24 h of incubation with tangeretin, and the tangeretin effect as assessed by DNA fragmentation or growth inhibition was significantly attenuated in the presence of Zn2+, which is known to inhibit Ca(2+)-dependent endonuclease activity. Ca2+ and Mg2+, in contrast, promoted the effect of tangeretin. Cycloheximide significantly decreased the tangeretin effect on HL-60 cell growth, suggesting that protein synthesis is required for flavonoid-induced apoptosis. Tangeretin showed no cytotoxicity against either HL-60 cells or mitogen-activated PBMCs even at high concentration (27 microM) as determined by a dye exclusion test. Moreover, the flavonoid was less effective on growth of human T-lymphocytic leukaemia MOLT-4 cells or on blastogenesis of PBMCs. These results suggest that tangeretin inhibits growth of HL-60 cells in vitro, partially through induction of apoptosis, without causing serious side-effects on immune cells.

Antineoplastic Agents↗
PubMed1995

Resistance to activated protein C activity of an anti-beta 2-glycoprotein I antibody in the presence of beta 2-glycoprotein I.

Some researchers claim that lupus anticoagulant-positive plasma may cause a false-positive reaction in the test for activated protein C (APC) resistance, a hereditary thrombophilic state characterized by abnormal factor V, which frequently causes venous thrombosis. We investigated whether anti-beta 2-glycoprotein I antibody (aGPI), which has recently come to be regarded as an anti-cardiolipin antibody (aCL) itself, might have an effect on the APC resistance test.

Antibodies, Anticardiolipin↗
PubMed1995

Effects of the pacing site, procainamide, and lead configuration on the relationship between the upper limit of vulnerability and the defibrillation threshold.

In six open chest dogs, we determined the upper limit of vulnerability (ULV) and defibrillation threshold (DFT) by an up-down algorithm when the pacing site was at the right atrium, at the left ventricular apex, and at the left ventricular base. Monophasic shocks (6 ms) were given to epicardial patches at 20 and 40 ms before the peak of the T wave to bracket the mid-upslope. In an additional six closed-chest dogs, we determined the ULV and the DFT with transvenous leads with an 8-ms biphasic waveform. The S1 pacing site was at the right ventricular apex and the right atrium, and the shocks were given at 20 ms and 40 ms before the peak of the T wave, and on the peak of T wave. The same test was repeated after intravenous procainamide infusion (20 mg/Kg loading, then 2 mg/min maintenance). In the first six dogs, the ULV determined when pacing was given to the left ventricular apex, the left ventricular base, and the right atrium was 4.2 +/- 1.7 J, 4.4 +/- 2.1 J, and 3.9 +/- 1.5 J, respectively; values that were not significantly different from the DFT of 4.8 +/- 1.9 J, 4.5 +/- 1.9 J, and 4.2 +/- 1.3 J, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Algorithms↗
PubMed1995

Prevalence of beta 2-glycoprotein I antibody in systemic lupus erythematosus patients with beta 2-glycoprotein I dependent antiphospholipid antibodies.

OBJECTIVE: To investigate whether beta 2-glycoprotein I antibody (aGPI) exists in sera that are positive for antiphospholipid antibodies (aPL). METHODS: Thirty six patients with systemic lupus erythematosus (SLE) and 20 healthy volunteers were recruited. GPI independent and dependent aPL (anticardiolipin (aCL), antiphosphatidylserine, antiphosphatidylinositol, antiphosphatidic acid) were measured using a conventional enzyme linked immunosorbent assay (ELISA). aGPI was measured by an ELISA using a gamma irradiated plate coated with purified GPI. RESULTS: Twenty of 36 SLE patients were positive for at least one of the GPI-dependent aPL. Five of these 20 were also positive for aGPI. Another five of the 20 showed low GPI dependency aCL antibodies; however, three of these patients required GPI for binding to phosphatidylserine, phosphatidylinositol, or both. CONCLUSION: We confirmed the existence of aGPI in patients with true GPI dependent aPL. From these results, we recommend the use of a gamma irradiated plate with GPI as antigen for the detection of true GPI dependent aPL or aGPI.

Antibodies, Anticardiolipin↗
PubMed1995

Plasmodium vivax malaria infection diagnosed by indirect fluorescent antibody test.

We present the diagnostically challenging case of a 51-year-old Japanese male who visited Papua New Guinea for one month. Approximately a month after returning to Japan, he experienced a high fever. Malaria was suspected and he was admitted to Tsukuba University Hospital. Although the blood smear did not reveal the malarial parasite, a diagnosis of malaria was made using an indirect fluorescent antibody test (IFAT). The patient was treated and discharged but symptoms returned three months later. This time, the blood smear was positive for malarial parasites. IFAT was useful in this case for the early diagnosis of Plasmodium vivax and for ruling out infection by Plasmodium falciparum.

Animals↗
PubMed1995

Relaxation effect of an audiovisual system on dental patients. Part 2. Palus-amplitude.

Dental care services include relaxation of patients to reduce their displeasure at and tension during treatment. For this purpose, it is common to use audio or audiovisual programs, that is, to let them listen to music or watch TV. However, the former utilizes only the auditory sense, and the latter is disadvantageous in that a TV set is a rather large-scale unit. In the present study, we determined the relaxation effect of an audiovisual instrument on dental patients. The instrument, which gives virtual vision, was composed of a lightweight eyeset of the snow goggle type that has a built-in TV screen, with earphone and accessories. The relaxation effect was determined using a polygraph.

Adult↗
PubMed1995

Urodynamic study of storage and evacuation of urine in patients with a urethral Kock pouch.

PURPOSE: The urodynamics of pouch-urethra function were investigated in patients with a urethral Kock pouch to understand mechanisms involved in the storage and evacuation of urine, and elucidate any problems of long-term outcome. MATERIALS AND METHODS: Urodynamic evaluation was performed in 18 male patients who underwent bladder replacement with a urethral Kock pouch following radical cystectomy. RESULTS: Good urinary continence was achieved with normal frequency of voiding. On urodynamics pressure within the pouch remained low during the storage phase (mean 33.2 cm. water) but markedly increased during the evacuation of urine (mean 77.3 cm. water). In 8 patients (44%) extremely high pressure within the pouch (80 to 150 cm. water) was noted at voiding. Clean intermittent self-catheterization was initiated in a patient with high pressure within the pouch at voiding in whom pouch-ureter reflux developed 7 months postoperatively. The external urethral sphincter was impaired to some extent postoperatively but it contracted in response to filling of the pouch with a marked increase in urethral pressure from a mean of 31.6 to 66.3 cm. water. CONCLUSIONS: Urodynamic and radiological studies will be necessary periodically since high pressure within the pouch at voiding might jeopardize the antireflux mechanism, leading to reflux and renal impairment.

Adult↗