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Biomedical subjects

Y Takeda

Publications and source records attributed to Y Takeda.

At least 271 records · Page 15Linked to original sources
PubMed1999

Purification and characterization of chondroitin 4-sulfotransferase from the culture medium of a rat chondrosarcoma cell line.

Chondroitin 4-sulfotransferase, which transfers sulfate from 3'-phosphoadenosine 5'-phosphosulfate to position 4 of N-acetylgalactosamine in chondroitin, was purified 1900-fold to apparent homogeneity with 6.1% yield from the serum-free culture medium of rat chondrosarcoma cells by affinity chromatography on heparin-Sepharose CL-6B, Matrex gel red A-agarose, 3',5'-ADP-agarose, and the second heparin-Sepharose CL-6B. SDS-polyacrylamide gel electrophoresis of the purified enzyme showed two protein bands. Molecular masses of these protein were 60 and 64 kDa under reducing conditions and 50 and 54 kDa under nonreducing conditions. Both the protein bands coeluted with chondroitin 4-sulfotransferase activity from Toyopearl HW-55 around the position of 50 kDa, indicating that the active form of chondroitin 4-sulfotransferase is a monomer. Dithiothreitol activated the purified chondroitin 4-sulfotransferase. The purified enzyme transferred sulfate to chondroitin and desulfated dermatan sulfate. Chondroitin sulfate A and chondroitin sulfate C were poor acceptors. Chondroitin sulfate E from squid cartilage, dermatan sulfate, heparan sulfate, and completely desulfated N-resulfated heparin hardly served as acceptors of the sulfotransferase. The transfer of sulfate to the desulfated dermatan sulfate occurred preferentially at position 4 of the N-acetylgalactosamine residues flanked with glucuronic acid residues on both reducing and nonreducing sides.

Animals↗
PubMed1999

Induction of cytokines in a human colon epithelial cell line by Shiga toxin 1 (Stx1) and Stx2 but not by non-toxic mutant Stx1 which lacks N-glycosidase activity.

Stx1 and Stx2 produced by Shiga toxin-producing Escherichia coli are cytotoxic due to their N-glycosidase activity on 28S rRNA. In this study, we have shown that proinflammatory cytokine mRNAs, especially IL-8, were induced by Stx1 and Stx2 in Caco-2 cells. A non-toxic mutant of Stxl which lacks N-glycosidase activity did not induce cytokine mRNAs. IL-8 production at the protein level was enhanced by Stx1 and Stx2, but not by the mutant Stx1. These results demonstrate that Shiga toxins induce expression and synthesis of cytokines in Caco-2 cells and their N-glycosidase activity is essential for the induction.

Amino Acid Substitution↗
PubMed1999

Microchimerism in thymus is associated with up-regulated T helper type 1 cytokine transcription during cardiac allograft rejection in rats.

BACKGROUND: Intrathymic microchimerism (MC) is thought to be responsible for inducing allograft tolerance. However, the role of MC in the thymus gland after transplantation, particularly in the rejection response, is unknown. We investigated serial changes in intrathymic cytokine production associated with MC and allograft rejection. METHODS: Donor-specific cell injection (DSI) and heterotopic heart transplantation (HTx) were performed in the fully allogeneic combination using DA rats (RT1a) as donors and WS rats (RT1k)as recipients. MC was checked by polymerase chain reaction (PCR) using a donor RT1.Bbeta domain 1 region sequence-specific primers. Reverse transcription (RT)-PCR analysis of cytokine (interleukin [IL]-2, interferon-gamma, IL-4, and IL-10) profiles of the thymus was performed in animals given DSI, HTx, or DSI/HTx. RESULTS: DSI alone resulted in an immediate development of MC, detected by PCR, in various organs including the thymus, spleen, liver, and blood, of most rats, lasting for over 2 months. However, DSI-induced MC selectively disappeared in the thymus on day 7 after grafting, several days before the rejection of cardiac allograft. RT-PCR analysis of cytokine profiles showed that the levels of Th1 (IL-2 and interferon-gamma) cytokines transcribed in the thymus were higher than in the spleen. MC reappeared in the thymus on day 21 after grafting, but was not associated with elevation of Th1 cytokine transcription when allograft was replaced by fibrosis. CONCLUSIONS: Intrathymic MC does not always confer unresponsiveness to alloantigen, but can be eliminated after anti-donor response.

Animals↗
PubMed1999

Analysis of the genes responsible for the O-antigen synthesis in enterohaemorrhagic Escherichia coli O157.

The genes responsible for O157 O-antigen synthesis were cloned from Shiga toxin 1 (Stx1)-producing enterohaemorrhagic Escherichia coli O157:H-. Based on the published sequence of the rfbE(EcoO157:H7) gene, the rfbE gene was amplified by PCR and used as the probe. One clone (1-4-1) out of ten agglutinated using the slide agglutination test with O157 antiserum. The DNA sequence of a 31.5 kb fragment in p1-4-1 was determined and found to contain 26 open reading frames (ORFs). These ORFs were organized as two clusters of genes, comprising orf2 to orf16 and orf17 to orf24 regions, which were aligned in opposite directions. The GC contents of orf1, orf12 and orf14 to orf26 were similar to the overall GC content of the E. coli chromosome (51%). However, orf2 to orf11 and orf13 showed a much lower GC content of 30.0 to 39.4%. The minimum region essential for O157 O-antigen expression in E. coli K-12 lay between orf2 and orf13, which corresponded to the region of low GC content in E. coli O157. A colony hybridization test was carried out against reference strains of E. coli representing serogroups O1 to O173 using O157 O-antigen synthesis genes (orf2-orf13) of E. coli O157 as probes. With the exception of orf12, all probes from E. coli O157 O-antigen synthesis gene cluster did not hybridize with DNA from E. coli O1 to O173, except O157 reference strains, under high stringency conditions. These data suggest that the region from orf2 to orf13 has originated from a non-E. coli species with a low GC content.

Bacterial Proteins↗
PubMed1999

Sclerotherapy with a ligation of incompetent veins for a stasis ulcer due to varix cruris: minimal invasive therapy for varix cruris.

A retrospective analysis was performed on 11 patients (mean age 50 years), consisting of 8 men and 3 women, with a stasis ulcer due to varix cruris who underwent sclerotherapy with a ligation of incompetent veins on an outpatient basis. The follow-up ranged from 26 to 76 months (mean 53 months). The ulcers healed in 14 to 128 days (mean 41 days) after this procedure except in 1 patient. Three patients healed within 1 month and 7 others within 2 months. Only 1 patient needed over 2 months to heal. A recurrence of the ulcer was observed in 1 case 59 days after healing, and incompetent perforating veins were newly identified. This patient required an additional endoscopic subfascial division of the perforating veins and is now in the process of healing. No deterioration of the ulcer was observed. Thrombophlebitis and faintness were observed in 1 patient each. Neither pulmonary embolism nor deep venous thrombosis was observed. In conclusion, sclerotherapy with a ligation of any incompetent veins was found to be a safe and effective treatment for a stasis ulcer due to varix cruris; however, long-term observation will be required to confirm the effectiveness of this procedure. To successfully use combination therapy with less or minimally invasive procedures, a precise diagnosis of vein incompetency is crucial.

Adult↗
PubMed1999

A new orally active antitumor 1R,2R-cyclohexanediamine-platinum(IV) complex: trans-(n-valerato)chloro(1R,2R-cyclohexanediamine) (oxalato)platinum(IV).

PURPOSE: The authors have previously reported that trans-bis(n-valerato)(1R,2R-cyclohexanediamine) (oxalato)platinum(IV) (C5-OHP), an oxaliplatin derivative, is an orally active antitumor agent in an intraperitoneal (i.p.) L1210 murine leukemia model. In this study, several oxaliplatin derivatives of the general formula trans-(carboxylato)chloro(1R,2R-cyclohexanediamine)(oxala to)platinum(IV) were synthesized in order to find new derivatives with greater oral activity than C5-OHP in a clinically predictive tumor model. In the formula, the carboxylate and chloride ligands are situated in axial positions. METHOD: Four complexes with the axial carboxylate ligands n-butyrate, n-valerate, n-caproate or n-heptanoate were synthesized and designated C4-OHP-Cl, C5-OHP-Cl, C6-OHP-Cl and C7-OHP-Cl, respectively. The oral antitumor activity of the complexes was evaluated against the murine reticulosarcoma M5076 implanted subcutaneoulsy (s.c.) in to male BDF1 mice. The complexes were administered orally daily for 5 days in two cycles initiated on days 5 and 12 postimplantation. The physicochemical properties were examined by measuring the concentrations of the complexes in test solutions at intervals by HPLC. The pharmacokinetic behaviors of C5-OHP-Cl, C6-OHP-Cl and C5-OHP following a single oral administration were studied in non-tumor-bearing male BDFl mice. RESULTS: Of the complexes synthesized in this study, C5-OHP-Cl, which exhibited high activity in the i.p. L1210 model, was found to be orally active in the s.c. M5076 model while C5-OHP was not. The in vitro reduction of the complexes by ascorbate was much more rapid than that of C5-OHP, while the complexes were more stable than C5-OHP in HCl-acidic and alkaline solutions. Pharmacokinetic study showed that Cmax and AUC0 24h values of plasma total and filterable platinum of C5-OHP-Cl were four to six times greater than those of C5-OHP, indicating that C5-OHP-Cl was absorbed more than C5-OHP. CONCLUSION: C5-OHP-Cl was found to be a superior 1-OHP derivative C5-OHP, exhibiting significant oral antitumor activity in the s.c. M5076 model. The enhanced activity of C5-OHP-Cl was considered to be due in part to increased susceptibility to reduction and increased gastrointestinal absorption. C5-OHP-Cl is a suitable candidate for further study as an oral cancer chemotherapy agent.

Administration, Oral↗
PubMed1999

Homologs of animal eyes absent (eya) genes are found in higher plants.

Homologs of the eyes absent (eya) gene in animals function at multiple stages in the development of organs. Their functional roles in the genetic network that regulates eye development in Drosophila have recently been extensively analyzed. A rice homolog of eya was identified from a cDNA library made from embryo RNA. The corresponding gene (OSEya1) encodes a conserved ED1 domain and a short N-terminal peptide. The ED1 domain of OSEya1 shows 25% identity and 36% similarity to the product of Drosophila eya. Mammalian and squid eya homologs show about 35% similarity to OSEya1. Homologous sequences were also found in the alfalfa EST database (53% identity and 65% similarity to OSEya1) and in the Arabidopsis genome sequence (63% identity). Therefore, eya homologs are present in both monocots and dicots. Three regions in the ED1 domain are well conserved in animals and plants. Plant eya products deduced from the nucleotide sequences also have short N-terminal peptides. The OSEya1 gene is located between the wx gene and the telomere on the short arm of chromosome 6. OSEya1 is expressed in the embryo, shoot apex, and caryopsis in rice. Expression in the embryo increases during embryogenesis until 7 days after pollination, with preferential localization in leaf primordia and the shoot apical meristem. Expression in the influorescence was observed in floral meristems. The functions of OSEya1 in higher plants are discussed and compared with those of their animal homologs. OSEya1 might regulate the morphogenesis of lateral organs as a subunit of a transcription factor.

Amino Acid Sequence↗
PubMed1999

Measurement of hepatocyte growth factor in serum and plasma.

To investigate whether serum or plasma should be used for the measurement of blood hepatocyte growth factor, the levels were compared in 28 normal subjects and 30 patients who had undergone surgery. The serum level was significantly higher than the plasma level. The serum and plasma hepatocyte growth factor levels differed markedly depending on the subjects, although overall there was a significant correlation between levels (r=0.862, P=0.0001). In serum obtained by the clotting of platelet- or leukocyte-containing plasma with thrombin, hepatocyte growth factor increased in proportion to the number of leukocytes. The difference between serum and plasma hepatocyte growth factor levels also correlated with the number of leukocytes in the patients (r=0.642, P=0.0004). Such a correlation was not observed for platelets. These findings suggest that the serum hepatocyte growth factor level does not strictly reflect the in vivo blood level, due to the release from leukocytes during sample preparation (i.e., blood clotting ) and that plasma is more suitable for assay of blood hepatocyte growth factor.

Blood Cell Count↗
PubMed1999

Novel polymorphisms in the upstream region of the human dopamine D4 receptor (DRD4) gene.

We found nine novel polymorphisms in the upstream region of the human dopamine D4 receptor (DRD4) gene of Japanese by direct sequencing. These polymorphisms are -809G > A, -768G > A, -616C > G, -603T > del, -602G > del, -600G > C, -376C > T, -291C > T, and -128G > T. One known polymorphism, -521C > T, was also recognized. Six of these sites were identified as restriction fragment length polymorphisms (RFLPs).

Humans↗
PubMed1999

Ameloblastic fibroma and related lesions: current pathologic concept.

Ameloblastic fibroma (AF) is a true mixed tumor, in which the epithelial and the ectomesenchymal elements are neoplastic. There are two rare variants of AF; granular cell AF and peripheral AF. Ameloblastic fibrosarcoma is a rare tumor, and is regarded as the malignant counterpart of the benign AF. Recent immunohistochemical study using MIB-1 shows labelling indices in the mesenchymal component of the recurrent AF and ameloblastic fibrosarcoma are quite high, in contrast with the conventional AF. Ameloblastic fibrodentinoma is a histologic variant of AF in which dentin or dentinoid tissue has formed, but there is no eveidence that ameloblastic fibrodentinoma exhibit a different biologic behavior than ordinary AF. Ameloblastic fibro-odontoma is a lesion similar to AF, but also showing inductive changes that lead to the formation of both dentin and enamel. Some lesions diagnosed as ameloblastic fibro-odontoma are probably developing odontoma, but the others should not be considered as hamartomatous in nature, since there are rare cases of ameloblastic fibro-odontoma showing true neoplastic behavior, and since the existence of malignant variant is evident. In revised WHO's classification of odontogenic tumors, the terms "ameloblastic fibrodentinoma" and "dentinoma" are used synonymously, however, there are histologic difference between several cases reported previously as "dentinoma" and ameloblastic fibrodentinoma.

Ameloblastoma↗
PubMed1999

Chemical studies on antioxidant mechanism of curcuminoid: analysis of radical reaction products from curcumin.

In the course of studies on the antioxidant mechanism of curcumin, its radical reaction was investigated. Curcumin was reacted with radical species, which were generated from the pyrolysis of 2, 2'-azobis(isobutyronitrile) under an oxygen atmosphere, and the reaction products from curcumin were followed by HPLC. The reaction at 70 degrees C gave several products, three of which were structurally identified to be vanillin, ferulic acid, and a dimer of curcumin after their isolation. The dimer was a newly identified compound bearing a dihydrofuran moiety, and its chemical structure was elucidated using spectroscopic analyses, especially 2D NMR techniques. A mechanism for the dimer production is proposed and its relation to curcumin's antioxidant activity discussed. The time course and gel permeation chromatography studies of the reaction were also investigated, and the results indicate that the dimer is a radical-terminated product in the initial stage.

Antioxidants↗
PubMed1999

Evaluation of the antioxidant activity of environmental plants: activity of the leaf extracts from seashore plants.

The antioxidant activity of the methanolic extracts of the leaves of 39 plant species was examined. These leaves were collected from the plants growing on subtropical seashores. The activity was evaluated by three kinds of assay methods, which included the DPPH radical scavenging assay, linoleic acid oxidation assay, and oxidative cell death assay. Two extracts from Excoecaria agallocha and Terminalia catappa showed remarkably potent activity in all assay systems. The HPLC analysis of the extracts indicated the presence of the same antioxidant and isolation work for the compound identified ellagic acid. The isolated ellagic acid showed strong antioxidant activity in the assay systems used.

Antioxidants↗
PubMed1999

Case report: Occurrence of hepatocellular carcinoma 4.5 years after successful treatment with virus clearance for chronic hepatitis C.

A 67-year-old man with hepatitis C virus infection and histological features of chronic active hepatitis was treated with human recombinant interferon alpha-2b. He responded successfully to interferon with normalization of serum alanine aminotransferase and continuous eradication of hepatitis C virus. However, 4.5 years after the end of interferon therapy, hepatocellular carcinoma, 20 mm in diameter, was detected by routine ultrasonographic screening. The patient underwent surgical treatment for resection of the hepatocellular carcinoma. The non-cancerous liver tissue was histologically normal. This suggests that patients who have shown a complete response to interferon therapy for chronic hepatitis C should be followed up closely.

Aged↗
PubMed1999

An immunohistochemical study of bizarre neoplastic cells in pleomorphic adenoma: its cytological nature and proliferative activity.

The cytological nature and proliferative activity of bizarre neoplastic cells, widely scattered in pleomorphic adenomas of salivary gland origin were studied. Pleomorphic adenomas containing numerous bizarre neoplastic cells were found in four cases, and were equal to 2.9% of all pleomorphic adenomas examined. All four cases presented as well-circumscribed, firm masses measuring less than 1.5 cm in size, located in the palate, and were of 7 months to 4 years duration. Histopathologically, these pleomorphic adenomas were cell rich type, and were well demarcated from surrounding tissues, although their fibrous capsules were partially defective. In addition to characteristic histopathological findings of pleomorphic adenoma, numerous neoplastic cells with bizarre appearance were scattered throughout the lesion, excepting for tubuloductal structures. These bizarre neoplastic cells had irregular-shaped and large nuclei with or without hyperchromatism, although their nucleoli were small and mitotic figures were few. Furthermore, there were many multinucleated giant cells, some of which showed multilobulated nuclei. Neither necrosis nor infarct was seen in the tumors. Immunohistochemically, bizarre neoplastic cells scattered in solid-proliferating areas and myxoid areas were neoplastic myoepithelial cells in nature. There was no statistical significance of MIB-1 labeling indices between pleomorphic adenomas with bizarre neoplastic cells and usual pleomorphic adenomas. The p53 labeling indices were quite low. Although the benign nature of pleomorphic adenomas with numerous bizarre neoplastic cells and hypercellularity, distinguishing such pleomorphic adenomas from various stages of malignant transformation in pleomorphic adenomas and other carcinomas should be made by histological section of submitted biopsy specimen or aspirated content for cytological diagnosis. The present paper suggests that the term 'bizarre cell pleomorphic adenoma' is an appropriate name for this neoplasm, in that it is distinguished from the usual benign pleomorphic adenoma which is easily diagnosed by routinely prepared histological or cytological stainings.

Adenoma, Pleomorphic↗
PubMed1999

A comparison of post-ictal headache between patients with occipital lobe epilepsy and temporal lobe epilepsy.

We investigated post-ictal headaches (PIH) using a questionnaire to ascertain their characteristics and compare them among different types of epilepsy. The subjects consisted of 34 patients with occipital lobe epilepsy (OLE) and 75 patients with temporal lobe epilepsy (TLE). PIH occurred in 62% of OLE and 23% of TLE (P < 0.05). The quality of pain in PIH was 'steady' in 71% of OLE and 29% of TLE (P < 0.05) as opposed to 'pounding'. Other factors, such as frequency, severity, duration, and accompanying symptoms showed no significant differences. We found very few patients with migraine-like headaches. Analyses of clinical factors, such as age at onset, duration of epilepsy, seizure frequency, family history of headache, and interictal headache did not reveal any relationship to PIH, although generalized tonic-clonic seizures are associated with PIH in TLE (P < 0.05). These results suggest that the nature of PIH may be different between OLE and TLE, and that the region of epileptic focus or spreading area of epileptic discharge may have a close relation to the induction of PIH. An association with migraine, which has been reported previously, was unclear in our study.

Adult↗