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Biomedical subjects

T Kumagai

Publications and source records attributed to T Kumagai.

At least 37 records · Page 2Linked to original sources
PubMed2001

Application of 2-(3,5,6-trifluoro-2-hydroxy-4-methoxyphenyl)benzoxazole and -benzothiazole to fluorescent probes sensing pH and metal cations.

2-(3,5,6-Trifluoro-2-hydroxy-4-methoxyphenyl)benzoxazole (3) and benzothiazole analogue (4) are prepared by the two-step procedures from the corresponding 2-(pentafluorophenyl)benzazoles. Benzoxazole 3 is applicable to a fluorescent probe sensing magnesium cation, and 4 is suitable for sensing zinc cation. Both fluorophores 3 and 4 are sensitive to the pH change at pH 7-8, resulting in large fluorescence enhancement under basic conditions. Their high sensitivity to pH and selectivity in metal cations are ascribed to the high acidity of the fluorophenol moiety.

Benzothiazoles↗
PubMed2001

Gene therapy utilizing the Cre/loxP system selectively suppresses tumor growth of disseminated carcinoembryonic antigen-producing cancer cells.

Recent clinical trials of cancer gene therapy have shown encouraging results for controlling localized tumors. However, to control metastatic or disseminated tumor cells, further modification of vectors is required to enhance specificity and infectivity against targets. We investigated whether utilization of the Cre recombinase(Cre)/loxP system contributes to enhanced antitumor effects together with minimal adverse reactions in specific gene therapy against disseminated carcinoembryonic antigen (CEA)-producing cancer cells in the peritoneal cavity of mice. CEA-producing cancer would be a good therapeutic target because it is found in lung, stomach and colon sites, which account for most cancers. We constructed a pair of recombinant adenoviral vectors (Ads), one of which expresses the Cre gene under the control of the CEA promoter (Ad.CEA-Cre); the other expresses the herpes simplex virus thymidine kinase (HSV-TK) gene (Ad.lox-TK), or the beta-galactosidase gene (beta-gal) by Cre (Ad.lox-beta-gal). Intraperitoneal coinjection of Ad.CEA-Cre and Ad.lox-beta-gal into mice with peritonitis carcinomatosa by CEA-producing tumor cells showed selective expression of the beta-gal gene in tumor foci. Coinfection of Ad.CEA-Cre and Ad.lox-TK followed by ganciclovir (GCV) administration significantly suppressed the total tumor weight in the peritoneal cavity of the mice to 13% of that of the untreated mice and 22% of that of the mice treated with Ad.CEA-TK/GCV, an Ad that expressed the HSV-TK gene driven by the CEA promoter alone. Moreover, treatment with Ad.CEA-Cre and Ad.lox-TK/GCV completely suppressed tumors in 4 of 10 (40%) mice without significant weight loss, although 2 of 10 mice treated with Ad.CAG-TK/GCV, an adenovirus vector that strongly but nonspecifically expressed the TK gene, died due to severe side effects including diarrhea, weight loss and liver dysfunction. These findings suggest that cell type-specific gene therapy using the Cre/loxP system is effective against disseminated cancer cells without significant side effects.

Adenoviridae↗
PubMed2001

Nonsense and frameshift mutations in ZFHX1B, encoding Smad-interacting protein 1, cause a complex developmental disorder with a great variety of clinical features.

Mutations in ZFHX1B, encoding Smad-interacting protein 1 (SIP1), have been recently reported to cause a form of Hirschsprung disease (HSCR). Patients with ZFHX1B deficiency typically show mental retardation, delayed motor development, epilepsy, microcephaly, distinct facial features, and/or congenital heart disease, in addition to the cardinal form of HSCR. To investigate the breadth of clinical variation, we studied DNA samples from six patients with clinical profiles quite similar to those described elsewhere for ZFHX1B deficiency, except that they did not have HSCR. The results showed the previously reported R695X mutation to be present in three cases, with three novel mutations-a 2-bp insertion (760insCA resulting in 254fs262X), a single-base deletion (270delG resulting in 91fs107X), and a 2-bp deletion (2178delTT resulting in 727fs754X)-newly identified in the other three. All mutations occurred in one allele and were de novo events. These results demonstrate that ZFHX1B deficiency is an autosomal dominant complex developmental disorder and that individuals with functional null mutations present with mental retardation, delayed motor development, epilepsy, and a wide spectrum of clinically heterogeneous features suggestive of neurocristopathies at the cephalic, cardiac, and vagal levels.

Abnormalities, Multiple↗
PubMed2001

A Drosophila haemocyte-specific protein, hemolectin, similar to human von Willebrand factor.

We identified a novel Drosophila protein of approximately 400 kDa, hemolectin (d-Hml), secreted from haemocyte-derived Kc167 cells. Its 11.7 kbp cDNA contains an open reading frame of 3843 amino acid residues, with conserved domains in von Willebrand factor (VWF), coagulation factor V/VIII and complement factors. The d-hml gene is located on the third chromosome (position 70C1-5) and consists of 26 exons. The major part of d-Hml consists of well-known motifs with the organization: CP1-EG1-CP2-EG2-CP3-VD1-VD2-VD'-VD3-VC1-VD"-VD"'-FC1-FC2-VC2-LA1-VD4-VD5-VC3-VB1-VB2-VC4-VC5-CK1 (CP, complement-control protein domain; EG, epidermal-growth-factor-like domain; VB, VC, VD, VWF type B-, C- and D-like domains; VD', VD", VD"', truncated C-terminal VDs; FC, coagulation factor V/VIII type C domain; LA, low-density-lipoprotein-receptor class A domain; CK, cysteine knot domain). The organization of VD1-VD2-VD'-VD3, essential for VWF to be processed by furin, to bind to coagulation factor VIII and to form interchain disulphide linkages, is conserved. The 400 kDa form of d-Hml was sensitive to acidic cleavage near the boundary between VD2 and VD', where the cleavage site of pro-VWF is located. Agarose-gel electrophoresis of metabolically radiolabelled d-Hml suggested that it is secreted from Kc167 cells mainly as dimers. Resembling VWF, 7.9% (305 residues) of cysteine residues on the d-Hml sequence had well-conserved positions in each motif. Coinciding with the development of phagocytic haemocytes, d-hml transcript was detected in late embryos and larvae. Its low-level expression in adult flies was induced by injury at any position on the body.

Amino Acid Sequence↗
PubMed2001

A strong association between HLA-DR9 and gelatin allergy in the Japanese population.

The frequency of HLA class I and II phenotypes was determined among 23 patients with positive gelatin IgE, eight of whom developed anaphylaxis, 18 patients who did not have gelatin IgE but who experienced non-immediate reactions after exposure to gelatin. HLA-DR9, which is unique to Orientals, was present in 56.5% of the gelatin IgE positive patients, as compared to control population frequency of 24% (P < 0.002). In the non-immediate reaction group, who did not generate IgE, phenotype distribution resembled controls. HLA-DR9 positive individuals have a relative risk of 4.1 for developing gelatin allergy with positive IgE.

Anaphylaxis↗
PubMed2001

The role of distinct p185neu extracellular subdomains for dimerization with the epidermal growth factor (EGF) receptor and EGF-mediated signaling.

The extracellular domain of p185(c-neu) can be viewed as a complex structure of four subdomains, two of which are cysteine-rich subdomains. We have investigated the contribution of these distinct p185(c-neu) extracellular subdomains to p185/epidermal growth factor receptor (EGFR) heteromer formation and EGF-induced heteromeric signaling. Our studies indicate that at least two separate p185 subdomains, a region spanning subdomains I and II and subdomain IV are involved in association of p185 with the EGFR. We also demonstrated that subdomain IV reduced the heteromeric signaling and transforming activities induced by EGF after associating with EGFR. When 126 aa were deleted from subdomain IV, this small subdomain IV-derived fragment could still lead to heterodimers with EGFR and suppress EGF-induced mitogen-activated protein kinase activation and subsequent transformation abilities. These data provide information about trans-inhibitory mechanisms of mutant p185 species and also indicate that both the entire and a part of subdomain IV may represent a therapeutic target for erbB-overexpressing tumors. Finally, these studies define a basic feature of receptor-receptor associations that are determined by cystine-knot containing subdomains.

Animals↗
PubMed2001

4-Hydroxy-2-nonenal is a powerful endogenous inhibitor of endothelial response.

There is increasing evidence that lipid peroxidation is involved in many of the pathophysiologies associated with cardiovascular diseases, such as atherosclerosis and the long-term complications of diabetes. Among the products which originate from the peroxidation of cellular membrane lipids, 4-hydroxy-2-nonenal (HNE) is believed to be largely responsible for the cytopathological effects observed during oxidative stress in vivo. Here we found that HNE dramatically inhibited the expression of adhesion molecules induced by inflammatory stimuli in human aortic endothelial cells. The inhibition was found to be accompanied by a significant reduction of NF-kappaB activation followed by nuclear localization. This and the observation that the HNE treatment of the cells resulted in a rapid reduction of intracellular glutathione levels suggest that redox regulation of NF-kappaB may be involved in the modulation of the endothelial response by reactive aldehydes.

Aldehydes↗
PubMed2001

Adenovirus-mediated gene therapy specific for small cell lung cancer cells using a Myc-Max binding motif.

Recent clinical trials of gene therapy for patients with thoracic cancers have shown that these treatments were well tolerated with minimal side effects and that we need to further enhance specificity as well as efficiency of gene transfer to target cancer cells. We previously reported that myc-overexpressing SCLC cell lines became selectively sensitive to ganciclovir (GCV) by transducing the herpes simplex virus thymidine kinase (HSV-TK) gene under the control of the Myc-Max response elements (a core nucleotide sequence, CACGTG) and that this construct (MycTK) could be utilized to develop a novel treatment against chemo-radio-resistant SCLC. We report here in vivo antitumor effects and safety of a replication-deficient adenoviral vector containing the Myc-Max binding motif (AdMycTK) on SCLC cells. In vitro infection with AdMycTK selectively rendered myc-overexpressing SCLC cell lines 63- to 307-fold more sensitive to GCV. In vivo injections with AdMycTK followed by GCV administration markedly suppressed the growth of myc-overexpressing tumors established in the subcutis or in the peritoneal cavity of athymic mice. On the other hand, infection with AdMycTK did not significantly affect either in vitro GCV sensitivity of the cells expressing very low levels of the myc genes or the growth of their subcutaneous tumors. Moreover, we observed no apparent side effects of this treatment including body weight loss or biochemical abnormalities in contrast to the treatment with AdCATK that conferred strong but nonspecific expression of the HSV-TK gene. These results suggested that AdMycTK/GCV therapy is effective on SCLC patients whose tumors overexpress myc family oncogenes.

Adenoviridae↗
PubMed2001

Cyclopentenone prostaglandins as potential inducers of intracellular oxidative stress.

In the present study, we find that cyclopentenone prostaglandins (PGs) of the J(2) series, naturally occurring derivatives of PGD(2), are potential inducers of intracellular oxidative stress that mediates cell degeneration. Based on an extensive screening of diverse chemical agents on induction of intracellular production of reactive oxygen species (ROS), we found that the cyclopentenone PGs, such as PGA(2), PGJ(2), Delta(12)-PGJ(2), and 15-deoxy-Delta(12,14)-PGJ(2), showed the most potent pro-oxidant effect on SH-SY5Y human neuroblastoma cells. As the intracellular events that mediate the PG cytotoxicity, we observed (i) the cellular redox alteration represented by depletion of antioxidant defenses, such as glutathione and glutathione peroxidase; (ii) a transient decrease in the mitochondrial membrane potential (Deltapsi); (iii) the production of protein-bound lipid peroxidation products, such as acrolein and 4-hydroxy-2-nonenal; and (iv) the accumulation of ubiquitinated proteins. These events correlated well with the reduction in cell viability. In addition, the thiol compound, N-acetylcysteine, could significantly inhibit the PG-induced ROS production, thereby preventing cytotoxicity, suggesting that the redox alteration is closely related to the pro-oxidant effect of cyclopentenone PGs. More strikingly, the lipid peroxidation end products, acrolein and 4-hydroxy-2-nonenal, detected in the PG-treated cells potently induced the ROS production, which was accompanied by the accumulation of ubiquitinated proteins and cell death, suggesting that the membrane lipid peroxidation products may represent one of the causative factors that potentiate the cytotoxic effect of cyclopentenone PGs by accelerating intracellular oxidative stress. These data suggest that the intracellular oxidative stress, represented by ROS production/lipid peroxidation and redox alteration, may underlie the well documented biological effects, such as antiproliferative and antitumor activities, of cyclopentenone PGs.

Aldehydes↗
PubMed2001

Molecular analysis of Japanese patients with Rett syndrome: Identification of five novel mutations and genotype-phenotype correlation.

Rett syndrome is an X-linked dominant neurodevelopmental disorder that affects females almost exclusively. The recent identification of mutations of the methyl-CpG-binding protein 2 gene (MECP2) in patients with RTT, encouraged us to analyze the gene in 37 Japanese patients divided into classical RTT (14 cases), variant RTT (13 cases), and mentally retarded patients with Rett-like features (10 cases). Mutations in MECP2 were identified from most of the patients with classical and variant RTT (25 of 27 cases). Six reported common mutations were detected in 17 cases, and rare single nucleotide substitutions were found in 3 patients. In addition, one insertion mutation (1189insA) and four deletion mutations including one double deletion mutant (451delG, 100del4, 1124del53 and 881del289 plus 1187del8) were newly identified. In the 10 mentally retarded patients with Rett-like features, however, no mutation was detected in the coding region of MECP2. The finding of MECP2 mutations in 92.5% of patients with RTT indicates that RTT fulfilling the diagnostic criteria are due to genetic alteration.

Amino Acid Substitution↗
PubMed2001

Evaluation of urinary rapid test for Helicobacter pylori in general practice.

There is increasing interest in noninvasive tests for the diagnosis of Helicobacter pylori (H. pylori) infection. One such test, a urine-based rapid test kit (RAPIRUN H. pylori Antibody, Otsuka Pharmaceutical Co., Ltd.) for detection of antibody to H. pylori, has been developed and is considered ideal. In addition to its noninvasiveness and safe handling-due to use of urine as a sample-the assay procedure used for the urinary rapid test is very simple. Only 10-20 minutes are required to complete an assay, and no instruments are needed. The aim of this study was to examine the clinical usefulness of this urine-based rapid test. A total of 189 patients, including 76 patients with gastroduodenal disease, were recruited. A pair of random single-void urine and serum samples was collected from each of the 189 patients, and antibody to H. pylori in the urine and serum samples was measured using the urine-based rapid test kit and three commercially available serum-based ELISA kits. For the patients with gastroduodenal disease, invasive diagnostic methods using endoscopic biopsy specimens such as culture, histology, and rapid urease test were also performed. The sensitivity, specificity, and accuracy of the urinary rapid test were evaluated on the basis of the three serum ELISA results or the invasive diagnostic results. In addition, various urinalyses were performed, and the effects of substances existing in urine on the urinary rapid test results were examined. Of the 189 patients, the urinary rapid test was positive for 110 (58.2%), negative for 78 (41.3%), and invalid for only one patient (0.5%). Based on the three serum-based ELISA results, the sensitivity, specificity, and accuracy of the urinary rapid test were 93.7, 88.9, and 92.2%, respectively. On the basis of the biopsy-based test results, the sensitivity of the urinary rapid test was 100% and its accuracy (95.2%) was equivalent or superior to that of each serum-based ELISA. In addition, no significant differences were observed between groups positive and negative on urinary rapid testing in any urinalysis parameter examined. The novel urinary rapid test kit evaluated in this study enables simple, rapid, and accurate diagnosis of H. pylori infection, and is an ideal test method for point-of-care testing.

Adult↗
PubMed2001

Molecular cloning, sequence analysis and expression of a novel gene induced by near-UV light in Bipolaris oryzae.

A cDNA clone derived from a novel gene (uvi-1) that is inducible by near-UV light was isolated by a differential screening procedure from a cDNA library of the fungus Bipolaris oryzae and characterized further. Sequence analysis of the clone revealed that uvi-1 encodes a protein with a putative molecular mass of 17 kDa; the UVI-1 protein shows significant similarity to a putative protein encoded by a cDNA which is expressed during appressorium formation in the rice blast fungus, Magnaporthe grisea. The corresponding genomic clone was also isolated, and Southern analysis of genomic DNA indicated the presence of a single copy of the uvi-1 gene in B. oryzae. Northern analysis showed that the uvi-1 transcripts are induced by exposure to near-UV light, but not by blue or red light. Furthermore, accumulation of uvi-1 transcripts is observed during differentiation of the appressorium.

Amino Acid Sequence↗
PubMed2001

Long-term prognosis of patients with West syndrome in Japan: social aspects.

Long-term social prognosis of 120 Japanese patients with West syndrome was surveyed using structured questionnaire at the age of 25.4 years in average. The survey revealed that ADL score remained null in one-fifth of cases; the majority entered in special education course for disabled children; only eleven cases were employed as a full-time worker. As to QOL, 60% of cases were spending daily life with joy. In summary, social prognosis of West syndrome is generally gloomy, but a proportion of patients can lead an independent social life, and an enriched social environment is the most influential factor for better prognosis

Adult↗
PubMed2001

Long-term prognosis of patients with West syndrome in Japan: medical aspects.

In this study, West syndrome prognosis over 20 years was described. All information was obtained from the primary caregivers of patients with West syndrome thorough questionnaires. Of the 259 respondents, 117 patients born between 1960 and 1980 were analyzed. At the age of 20 years two patients were deceased, of the surviving patients, 40% of patients had seizures daily or weekly and 25.2% had been seizure-free for at least 3 years. There was significant difference in the seizure persistence value between West syndrome etiologies but not between the birth cohorts; of those born in the 1960s and 1970s. Compared with severe seizure persistence, which was the duration of the existing daily or weekly seizures at each age, there were no significant difference between birth cohorts and West syndrome etiologies.

Adolescent↗
PubMed2001

Synthesis and structure-affinity relationships of 4-(5-Aryl-1,2,3,6-tetrahydropyridino)pyrimidine derivatives as corticotropin-releasing factor(1) receptor antagonists.

Recently, various non-peptide corticotropin-releasing factor(1) (CRF(1)) receptor antagonists have been reported. Structure-affinity relationships (SARs) of non-peptide CRF(1) antagonists suggest that such antagonists can be constructed of three units: a hydrophobic unit (Up-Area), a proton accepting unit (Central-Area), and an aromatic unit (Down-Area). We previously presented 4-aryl-1,2,3,6-tetrahydropyridinopyrimidine derivatives including potent CRF receptor ligands 1a and 1b and proposed that the 4-aryl-1,2,3,6-tetrahydropyridino moiety might be useful as a substituent in the Up-Area. Our interest shifted to 5-aryl-1,2,3,6-tetrahydropyridinopyrimidine derivatives 2, among which compound 2m (CRA0165) had highest affinity for CRF(1) receptors (IC(50)=11nM). We report here the design, synthesis and SARs of derivatives 2.

Animals↗
PubMed2001

Chemical modification of aryl-1,2,3,6-tetrahydropyridinopyrimidine derivative to discover corticotropin-releasing factor(1) receptor antagonists: aryl-1,2,3,6-tetrahydropyridino-purine, -3H-1,2,3-triazolo[4,5-d)pyrimidine, -purin-8-one, and -7H-pyrrolo[2,3-d]pyrimidine derivatives.

Structure-affinity relationships (SARs) of non-peptide CRF(1) antagonists suggest that such antagonists can be constructed of three units: a hydrophobic unit (Up-Area), a proton accepting unit (Central-Area), and an aromatic unit (Down-Area). Recently, various non-peptide corticotropin-releasing factor(1) (CRF(1)) receptor antagonists obtained by modification of the Central-Area have been reported. In contrast, we modified the Up-Area and presented 4- or 5-aryl-1,2,3,6-tetrahydropyridinopyrimidine derivatives including potent CRF receptor ligands 1a-c, and proposed that the 4- or 5-aryl-1,2,3,6-tetrahydropyridino moiety might be useful as a substituent in the Up-Area. Our interest shifted to the chemical modification in which the pyrimidine ring of 1a-c was replaced by other heterocycles, purine ring of 2, 3H-1,2,3-triazolo[4,5-d]pyrimidine ring of 3, purin-8-one ring of 4 and 7H-pyrrolo[2,3-d]pyrimidine ring of 5. Among them, 5-aryl-1,2,3,6-tetrahydropyridinopurine compound 6j (CRA0186) had the highest affinity for CRF(1) receptors (IC(50)=20nM). We report here the synthesis and SARs of derivatives 6-9.

Affinity Labels↗