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Biomedical subjects

T Sugimura

Publications and source records attributed to T Sugimura.

At least 145 records · Page 8Linked to original sources
PubMed1998

Linkage mapping of the Bra, Brb and Brg genes for rat protein phosphatase 2A 55 kDa B-regulatory subunit isotypes.

We previously identified the rat Bra, Brb and Brg genes, which encode alpha, beta and gamma isotypes of the 55 kDa B-regulatory subunit of protein phosphatase 2A. Polymerase chain reaction-single strand conformation polymorphism analysis in the present study identified polymorphisms in Bra, Brb and Brg between the ACI and BUF, ZI and TM, and BN and WTC strains, respectively. Linkage analysis using mapping panels composed of F2 or back-crosses of these strains allowed Bra, Brb and Brg to be assigned to chromosomes 15, 18 and 14, respectively. Furthermore, it was revealed that Bra is located close to the Rb1 locus. Using polymorphism in Bra, loss of heterozygosity (LOH) was analyzed for rat mammary tumors induced in (SD x F344) F1 female rats by a food-borne carcinogen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, and a typical mammary carcinogen, 7,12-dimethylbenz[a]anthracene. No LOH was detected at the Bra locus.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1998

Purification of pierisin, an inducer of apoptosis in human gastric carcinoma cells, from cabbage butterfly, Pieris rapae.

A substance strongly cytotoxic to human carcinoma cell line TMK-1 has been found in pupae, larvae and adults of the cabbage butterfly, Pieris rapae, and named pierisin. Pierisin was purified from the pupae of P. rapae by ammonium sulfate precipitation followed by DEAE-cellulose, Phenyl-Sepharose and hydroxyapatite column chromatographies. The molecular weight of the purified pierisin, which was homogenous on SDS-polyacrylamide gel, was analyzed by mass spectrometry and found to be 98 kDa. Pierisin showed a strong cytotoxic effect, with and IC50 of 0.75 ng/ml for human gastric carcinoma TMK-1 cells. The dying cells exhibited characteristic morphological features of apoptosis, such as cell shrinkage, chromatin condensation and nuclear fragmentation. Oligonucleosomal DNA fragmentation was also observed in DNA isolated from pierisin-treated cells. Moreover, similar characteristic changes showing apoptotic cell death were observed in TMK-1 cells treated with a crude extract of pupae of P. rapae. These results indicate that pierisin from the pupae of P. rapae induces apoptosis in human carcinoma cells.

ADP Ribose Transferases↗
PubMed1998

THA revision with extensively porous-coated stems. 32 hips followed 2-6.5 years.

Since 1991, we have used 32 extensively porous-coated femoral stems with cylindrical distal cross-section for revision of failed cemented stems. At an average follow-up of 4 years, one stem had been re-revised due to a periprosthetic femoral fracture, but no aseptic loosening has been observed. The average postoperative Harris Hip Score was 84 points. Radiographically, 23 stems were well fixed with bone-ingrowth, which was mostly observed in the distal portion of the porous coating. Increased thickness and density of the thin cortical wall was also seen. Mild stress shielding was present in 4 cases, but was not progressive and gave no symptoms. An extensively porous-coated stem, with a cylindrical distal cross-section, seems to be a reasonable choice in femoral revision.

Aged↗
PubMed1998

The human poly(ADP-ribose) glycohydrolase maps to chromosome 10q11.23-21.1 by fluorescence in situ hybridization.

Poly(ADP-ribose) glycohydrolase (PARG) digests poly(ADP-ribose), which is synthesized by poly(ADP-ribose) polymerase (PARP) after DNA damage. We mapped the human poly(ADP-ribose) glycohydrolase gene to chromosome 10q11.23-21.1 by fluorescence in situ hybridization analysis. Since chromosomal rearrangements in thyroid papillary carcinoma and loss of heterozygosity in glioblastoma are frequently observed in this region, genetic alteration of PARG could be implicated in these diseases.

Base Sequence↗
PubMed1997

Effects of gender and species on spectra of mutation induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in the lacI transgene.

Feeding of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) to F344 rats induces colon tumors specifically in male rats. Mutant frequencies and mutational spectra of the lacI transgene were studied in male and female Big Blue transgenic rats after feeding 400 ppm of PhIP in the diet for 60 days. Mutant frequencies in the colon mucosa were increased 20-25 times compared with those of the control rats, being 661.4 +/- 33.3 x 10(-6) and 718.2 +/- 16.9 x 10(-6) in males and females, respectively. No significant differences in types and distribution of the mutations were detected between males and females. One-base deletions were the most frequent mutation, including the characteristic guanine deletion at 5'-GGGA-3' which is also seen in the Apc gene of rat colon cancers induced by PhIP. Comparison of the lacI mutations in the rat colon with those previously identified in the mouse colon showed that the rate of G to T transversions was significantly higher in the mouse. This is the first report stating that there exist differences in the mutation specificity on the same gene, among mammalian species. However, the characteristic guanine deletion was recovered in both the mouse and the rat. These findings do not offer a mechanistic explanation of the gender specificity of PhIP-induced colon cancer in rats, though the universality of the guanine deletion suggests that this alteration may prove a useful indicator of human exposure.

Animals↗
PubMed1997

Interventional treatment for children with severe coronary artery stenosis with calcification after long-term Kawasaki disease.

BACKGROUND: About 4% of children with Kawasaki disease (KD) eventually develop ischemic heart disease, which is often associated with calcified stenosis. We assessed the utility of the percutaneous transluminal coronary rotational ablation (PTCRA) in children with coronary artery stenosis after KD. METHODS AND RESULTS: Four children (three boys and one girl; age, 12 to 13 years) with coronary artery stenosis underwent percutaneous transluminal coronary angioplasty (PTCA) and PTCRA 11.8+/-0.9 years after the onset of KD. Morphology of the coronary artery wall was evaluated by intravascular ultrasound imaging. In one patient, the targeted lesion for intervention was in the left anterior descending artery (90% stenosis); in the other three patients, it was in the middle of the right coronary artery (75% to 90% stenosis). PTCA failed in three patients because of severe stenosis with calcification. However, PTCRA proved effective, with stenosis rates reduced from 90% to 25%. Follow-up coronary angiography performed 4 months after the procedure demonstrated no restenosis, but mild aneurysms occurred in two patients. CONCLUSIONS: This study suggests that PTCRA is useful for revascularizing coronary arteries with severe stenosis and calcification as long-term sequelae of KD. Intravascular ultrasound imaging is useful in assessing the coronary artery wall pathology and in selecting the best treatment intervention.

Adolescent↗
PubMed1997

Growth regulation of human prostate cancer cells by bone morphogenetic protein-2.

Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-beta (TGF-beta) family and have been identified as factors that stimulate bone formation in vivo. They turned out to be multifunctional molecules regulating the growth, differentiation, and apoptosis in various target cells. Some BMPs and their receptors (BMPRs) are expressed on prostate cancer cells. We have reported previously that BMPR-IB mRNA expression is highest in the prostate, a characteristic that is not shared by the other BMPRs, BMPR-IA and BMPR-II. However, the amounts of BMPR-IB mRNA were significantly low in prostate tissues after androgen withdrawal therapy. They were also low in prostate cancer cell lines. Semiquantitative RT-PCR showed that BMPR-IB mRNA was induced by androgen in the androgen-sensitive human prostatic cancer cell line LNCaP, whereas the expression of BMPR-IA and BMPR-II mRNAs was not affected by androgen. When the recombinant human BMP-2 was added to the LNCaP cells in the presence of androgen, cell growth was inhibited. In contrast, the growth rate was increased by the addition of the same ligand when the cells were cultured in the absence of androgen; under this condition, the amounts of BMPR-IB mRNA were decreased significantly. These observations showed that the amounts of BMPR-IB, but not those of BMPR-IA, were regulated by androgen and further suggest that BMPR-IA and BMPR-IB differentially modulate prostate cancer cell growth in response to BMP under different hormonal conditions; BMPR-IA elicits growth stimulation, and BMPR-IB conveys a negative regulatory signal in response to BMP-2.

Bone Morphogenetic Protein 2↗
PubMed1997

Induction of minisatellite mutation in NIH 3T3 cells by treatment with the tumor promoter okadaic acid.

Okadaic acid (OA) is a strong tumor promoter of mouse skin carcinogenesis and also a potent inhibitor of serine/threonine protein phosphatases. OA induces various genetic alterations in cultured cells, such as diphtheria-toxin-resistance mutations, sister chromatid exchange, exclusion of exogenous transforming oncogenes, and gene amplification. The present study revealed that it caused minisatellite mutation (MSM) at a high frequency in NIH 3T3 cells, although no microsatellite mutation was found. Nine of 31 clones (29%) exhibited MSM after 6 days of OA treatment, as opposed to only 1 of 30 clones (3%) without OA exposure. Moreover, NIH 3T3 cells treated with OA acquired tumorigenicity in nude mice, giving rise to 7 tumors within 25 weeks in 20 sites where 3 x 10(6) cells were injected. In contrast, the same numbers of untreated cells gave rise to only one tumor, and the tumor grew much slower. All of three OA-induced tumors examined manifested the MSM. The findings thus point to a molecular mechanism by which OA could function as a tumor promoter, and also the biological relevance of the induction of MSM in the tumorigenic process by OA.

3T3 Cells↗
PubMed1997

Minisatellite instability in severe combined immunodeficiency mouse cells.

We have recently found that okadaic acid, which shows strong inhibitory activity on protein serine/threonine phosphatases and tumor-promoting activity in vivo and in vitro, induces minisatellite mutation (MSM). Human tumors and chemically induced counterparts in experimental animals are also sometimes associated with MSM. In the present study, we demonstrated minisatellite (MS) instability in severe combined immunodeficiency (SCID) cells in which the DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is impaired. Cells from a SCID fibroblast cell line transformed by simian virus 40 large tumor antigen, SC3VA2, and from an embryonal SCID fibroblast cell line, SC1K, were cloned and propagated to 10(7) to 10(8) cells, and then subjected to subcloning. After propagation of each subclone to 10(7) to 10(8) cells, DNA samples were digested with HinfI and analyzed by Southern blotting using the Pc-1 MS sequence as a probe. Under low-stringency conditions, about 40 MS bands were detected, with 45% +/- 6% and 37% +/- 3% of SC3VA2 and SC1K cells, respectively, having MSM. In contrast, cells from the RD13B2 cell line, which was established from SCVA2 by introducing human chromosome 8q fragments, on which DNA-PKcs is known to reside, to complement the SCID phenotype, showed a very low frequency of MSM (3% +/- 3%). The high frequencies of MSM in SC3VA2 and SC1K were significant, with no difference between the two. The present study clearly demonstrates that MS instability exists in SCID fibroblasts, suggesting that DNA-PKcs might be involved in the stable maintenance of MS sequences in the genome.

Animals↗
PubMed1997

Isolation of a candidate gene, CAB1, for cholesterol transport to mitochondria from the c-ERBB-2 amplicon by a modified cDNA selection method.

An improved cDNA selection method was established to isolate expressed genes efficiently from an amplified chromosome region in human cancer. Biotinylated yeast artificial chromosome DNA containing c-ERBB-2 was hybridized in solution with PCR-amplifiable cDNAs of an esophageal cancer cell line bearing the c-ERBB-2 amplification. After capturing the hybrids on avidin-coated magnetic beads, the cDNAs were amplified by PCR. Four new genes (A39, C51, CAB1, and GRB-7) coamplified with c-ERBB-2 were isolated from the enriched cDNA library. CAB1, GRB-7, and c-ERBB-2 were overexpressed in gastric and esophageal cancer cells in correspondence with the amplification. The deduced amino acid sequence of the CAB1 gene had significant homology to the recently discovered steroidogenic acute regulatory protein, StAR, which plays an essential role in cholesterol transport to mitochondria. It was established that multiple overexpressed genes are frequently present in a single amplicon.

Amino Acid Sequence↗
PubMed1997

Gene therapy for peritoneal dissemination of pancreatic cancer by liposome-mediated transfer of herpes simplex virus thymidine kinase gene.

Peritoneal dissemination is one of the most common complications of the malignancies of the digestive system, such as gastric or pancreatic cancers. Yet, no effective therapy has been established so far to alleviate this devastating and often fatal end-stage condition. Here we describe a novel approach of intraperitoneal (i.p.) lipofection of a suicidal gene to the pancreatic cancer cells in a mouse peritoneal dissemination model. A human pancreatic cancer cell line, PSN-1, was inoculated into the peritoneal cavity of nude mice. Eight days later, a herpes simplex virus thymidine kinase (HSV-TK) gene expression plasmid under a potent hybrid promoter CAG was injected as a DNA-lipopolyamine complex. Ganciclovir (GCV) was then administered for 8 days, and the mice were examined for tumor development at the 24th day after the tumor inoculation. Although all 24 control mice showed macroscopic peritoneal dissemination and solid tumors on the pancreas, 8 of the 14 mice treated with HSV-TK and GCV were free of tumors, and only a few small tumors were observed in the remaining 6 mice. Treatment-related toxicity was not observed. The semiquantitative reverse transcription polymerase chain reaction (RT-PCR) analysis suggested that the HSV-TK transgene was expressed in about 10% of tumor cells but not in the normal pancreas or in the small intestine. When the lacZ gene was transduced in place of the HSV-TK gene, the blue-stained cells were identified only in tumor nodules and not in normal organs. This preclinical study suggests the therapeutic feasibility of the i.p. lipofection-based suicidal gene/prodrug strategy for peritoneal dissemination of pancreatic cancer.

Animals↗
PubMed1997

Genetic changes induced by heterocyclic amines.

Clarification of the mutational fingerprints of HCAs offers a promising approach in the investigation of the role of heterocyclic amines (HCAs) in human carcinogenesis. We analyzed mutations in the tumor related genes of tumors induced by HCAs, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), which mainly yield DNA-adducts of C8-guanine. The G-->T transversion at codon 13-2nd position in Ha-ras was predominantly observed in mouse forestomach and rat Zymbal gland tumors induced by MeIQ. In contrast, various types of mutation were detected in the ras family genes of rat Zymbal gland tumors induced by IQ; the presence of a methyl group at position 4 of imidazo[4,5-f]quinoline gave rise to a remarkable difference in the mutational fingerprint. Apc mutations were detected in PhIP- and IQ-induced rat colon tumors, with incidences of 50% (4/8) and 15% (2/13), respectively. All five mutations detected in the four PhIP-induced tumors consisted of a guanine deletion from the 5'-GGGA-3' sequence, in contrast with T to C and C to T mutations in IQ-induced tumors. Four of these five mutations shared seven common nucleotides, -GTGGGAT- surrounding the guanine; indicating that PhIP leaves a characteristic mutational fingerprint in Apc. Colon tumors induced by PhIP were also found to have mutations in their microsatellite sequences, and similar results were detected in mammary gland tumors induced by PhIP, contrasting with no mutations in IQ-induced colon tumors and a very low frequency of mutations in 7,12-dimethylbenz[a]anthracene (DMBA)-induced mammary tumors. Although the mechanisms involved in the induction of microsatellite mutations are not known yet, microsatellite mutations which can also be detected in sporadic human tumors, including colon and breast tumors, were indicated to be a characteristic of PhIP. Mammary tumors induced by PhIP showed loss of heterozygocity (LOH) at the distal part of chromosome 10, which shows synteny with the distal part of human chromosome 17, where LOH frequently occurs in human breast cancer. In conclusion, each heterocyclic amine leave a mutational fingerprint which is specific to each compound. Since the tumor-related genes involved in PhIP-induced tumors have characteristics in common with those in human cancers, further detailed analysis will provide us with useful information on mutational fingerprints, and on the possible contribution of PhIP to human colon cancer.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1997

Metabolism of food-derived heterocyclic amines in nonhuman primates.

During the cooking of meats, several highly mutagenic heterocyclic amines (HCAs) are produced. Three HCAs, IQ, MeIQx, and PhIP have been under study for carcinogenicity in cynomolgus monkeys, and to date, IQ has been shown to be a potent hepatocarcinogen. Concomitantly, the metabolic processing of these HCAs has been examined. Metabolism studies show that the potent hepatocarcinogenicity of IQ is associated with the in vivo metabolic activation of IQ via N-hydroxylation and the formation of DNA adducts. In monkeys undergoing carcinogen bioassay with IQ, N-hydroxylation was confirmed by the presence of the N-hydroxy-N-glucuronide conjugate of IQ in urine. The N-hydroxylation of IQ appears to be carried out largely by hepatic CYP3A4 and/or CYP2C9/10, and not by CYP1A2, an isoform not expressed in liver of this species. Notably MeIQx is poorly activated in cynomolgus monkeys and lacks the potency of IQ to induce hepatocellular carcinoma after a 5-year dosing period. The poor activation of MeIQx appears to be due to the lack of constitutive expression of CYP1A2 and an inability of other cytochromes P450, such as CYP3A4 and CYP2C9/10, to N-hydroxylate the quinoxalines. MeIQx is detoxified in monkeys largely by conjugation with glucuronide at the N-1 position. Although the carcinogenicity of PhIP is not yet known, the metabolic data suggest that PhIP will be carcinogenic in this species. PhIP is metabolically activated in vivo in monkeys by N-hydroxylation, as discerned by the presence of the N-hydroxy-N-glucuronide conjugate in urine, bile, and plasma. PhIP also produces DNA adducts that are widely distributed in tissues. The results from these studies support the importance of N-hydroxylation in the carcinogenicity of HCAs in nonhuman primates and by analogy, the importance of this metabolic activation step in the possible carcinogenicity of dietary HCAs in humans.

Amines↗
PubMed1997

Human exposure to mutagenic/carcinogenic heterocyclic amines and comutagenic beta-carbolines.

Various kinds of mutagenic and carcinogenic heterocyclic amines (HCAs) are produced by heating protein-rich foods, such as meat and fish. To evaluate the risk of these HCAs in terms of human cancer development, exposure levels must be measured. We therefore analyzed their amounts in various kinds of cooked foods and in urine samples of healthy volunteers living in Tokyo. Based on the obtained quantitative data, daily exposure levels to 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) were calculated to be 0.3-3.9 and 0.005-0.3 microgram per person, respectively. Moreover, human DNA samples were analyzed with the 32P-postlabeling method, and colon, rectum and kidney tissues were found to contain an adduct spot corresponding to the standard 5'-pdG-C8-MeIQx by TLC and HPLC, at levels of 14, 18 and 1.8 per 10(10) nucleotides, respectively. The beta-carboline compound, norharman, is produced by heating L-tryptophan, and is known to be present in cooked foods and in cigarette smoke at higher levels than mutagenic and carcinogenic HCAs. While norharman is not itself mutagenic to Salmonella, it does become mutagenic to S. typhimurium TA98 with S9 mix in the presence of non-mutagenic aromatic amines like aniline and o-toluidine. When we examined whether DNA adducts are formed in the DNA of S. typhimurium TA98 by treatment with norharman and aromatic amines using 32P-postlabeling analysis, DNA adduct formation by norharman with aromatic amines was found to be related to the appearance of mutagenicity by norharman with aromatic amines.

Aniline Compounds↗
PubMed1997

BRCA2 germline mutations in Japanese breast cancer families.

Germline mutations of BRCA2 were examined in 20 Japanese breast cancer families without BRCA1 mutations, including one demonstrating cancer development in a male. Three different mutations, resulting in truncation of the BRCA2 protein, were detected in 3 different families. They were 9474insA (exon 24, termination at codon 3110), C8729A (exon 20, S2834 ter) and 982del4 (exon 9, termination at codon 275). The 982del4 mutation was detected in the family with a case of male breast cancer. Age at onset was young, with a range of 28-43 years, in the 2 female breast cancer families with truncation mutations. One probable missense mutation, A10462G (13412V), was further detected in 2 families, although cosegregation of this allele with the breast cancer phenotype was not complete. The rate of BRCA2 mutations in Japanese families was suggested to be almost the same as in Western countries, and larger than it is the case for BRCA1.

Adult↗