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Biomedical subjects

T Tsuji

Publications and source records attributed to T Tsuji.

At least 325 records · Page 18Linked to original sources
PubMed1999

Reperfusion accelerates the distribution of type I and III collagen messenger RNA expression after acute myocardial infarction: in situ hybridization in experimental infarction in rats.

BACKGROUND: The effects of reperfusion on the time-dependent appearance and distribution of type I and III collagen messenger RNA (mRNA) expression had not hitherto been examined. OBJECTIVE: To compare the sequential changes in the extent of distribution of type I and III collagen mRNA expression in reperfused infarct hearts of rats with those in unreperfused infarct hearts. METHODS: Using an experimental rat model of infarction, we examined type I and III collagen mRNA expression with specific rat pro alpha 1 (I) and human pro alpha 1 (III) collagen riboprobes by in-situ hybridization. Reperfusion was established after a 2 h coronary ligation that produced complete necrosis of the myocytes. RESULTS: Positive signals both for alpha 1 (I) and for alpha 1 (III) collagen mRNA appeared in the infarct peripheral zone 12 h after coronary ligation both of the reperfused and of unreperfused hearts. The spread of signal into the infarct central zone occurred 1-2 days earlier for the reperfused hearts than it did for the unreperfused hearts. The difference between the distributions of signals for the reperfused and unreperfused hearts became obscure on day 14. No notable difference between the extents of signal distribution for alpha 1 (I) and alpha 1 (III) collagen mRNA was obtained. We observed intense signals from spindle-shaped mesenchymal cells (myofibroblasts and fibroblasts) located between surviving myocytes in the marginal zone of the infarct. No myocyte exhibited signals both for alpha 1 (I) and for alpha 1 (III) collagen mRNA. CONCLUSION: In the present study, using in-situ hybridization, we demonstrated that reperfusion accelerates the distribution of expression both of alpha 1 (I) and of alpha 1 (III) collagen mRNA in the infarct zone after acute myocardial infarction in rats.

Animals↗
PubMed1999

[Causative organisms of acute otitis media and acute sinusitis in children and their susceptibility of oral beta-lactam antibiotics].

The clinical efficacy of cefditoren pivoxil (CDTR-PI) was evaluated for 43 pediatric patients with acute otitis media or acute sinusitis. The causative organisms were identified and their susceptibilities to 6 oral beta-lactam antibiotics were measured; ampicillin (ABPC), cefaclor (CCL), cefdinir (CFDN), cefditoren pivoxil (CDTR-PI), cefteram pivoxil (CFTM-PI) and cefpodoxime proxetil (CPDX-PR). The ages of 43 patients were distributed from 4 months to 10 years and 7 months, and especially children under 4 years accounted for 72% (31 cases). In 22 cases (51%), Haemophilus influenzae or Streptococcus pneumoniae were identified as the pathogens, but in 18 cases, no causative organisms were defined. Treatment by CDTR-PI was successful in 12 cases out of 15 evaluable cases in which H. influenzae or S. pneumoniae were identified as the main causative organisms. From the susceptibility testing of them, some strains of H. influenzae were found to be ABPC-resistant and some strains of S. pneumoniae were benzylpenicillin (PCG)-resistant. To support above clinical evaluation of CDTR-PI, susceptibility testings on clinically isolated H. influenzae (81 strains) and S. pneumoniae (79 strains) were performed using above mentioned 6 oral beta-lactam antibiotics. The MIC80s against H. influenzae were; CDTR-PI 0.06 microgram/ml, CCL 2 micrograms/ml, CPDX-PR 0.125 microgram/ml, CFTM-PI 0.03 microgram/ml, CFDN 1 microgram/ml and ABPC 1 microgram/ml. Those against S. pneumoniae were; CDTR-PI 0.5 microgram/ml, CCL > 4 micrograms/ml, CPDX-PR 2 micrograms/ml, CFTM-PI 1 microgram/ml, CFDN 2 micrograms/ml and ABPC 1 microgram/ml. From those results, it was concluded that CDTR-PI or CFTM-PI may be preferable for the treatment of acute otitis media and acute sinusitis in children.

Acute Disease↗
PubMed1999

[Indication of percutaneous microwave coagulation therapy for hepatocellular carcinoma].

Multifocal carcinogenesis is caused by a persistent infection of hepatitis viruses, and is considered to be the main cause of post-operational recurrences of hepatocellular carcinoma. It has been generally believed that a single therapeutic modality (including resection therapy) cannot improve the survival rate. In this paper, we describe the efficacy of microwave coagulation therapy and its indications based on an analysis of cases experienced at our institution over a 10-year period. We compared the background factors, recurrence rate, and survival rate of various therapies, and concluded that microwave coagulation therapy is highly effective for tumor coagulation and necrosis. Microwave coagulation therapy is also technically easier than a surgical operation, has fewer complications, and results in an equally good survival rate when compared to hepatectomy. Due to these intrinsic advantages, microwave therapy is useful not only as a treatment after recurrence, but also as a primary therapy of small liver tumors. When the detection rate for small liver tumors increases, microwave coagulation therapy will start to play an even more important role in the treatment strategy for hepatocellular carcinomas as a less invasive option, in addition to laparotomic and percutaneous/laparoscopic surgeries.

Carcinoma, Hepatocellular↗
PubMed1999

Synthesis and antitumor activities of amino acid prodrugs of amino-combretastatins.

The synthesis and antitumor activity of water-soluble amino acid prodrugs of amino-combretastatins were reported. Among the synthesized compounds, 7e (CS-39-L-Ser HCI, AC-7700) showed enhanced antitumor activity and decreased toxicity in a Colon 26 murine adenocarcinoma model. Compound 7e showed improved solubility and was easily formulated for in vivo administration. Compound 7e was cleaved to generate the parent compound, CS-39, in the whole blood of mice as well as man, possibly by the action of amino peptidase on the erythrocyte membrane.

Animals↗
PubMed1999

One-step direct assay for mature-type adrenomedullin with monoclonal antibodies.

Adrenomedullin (AM) is a potent hypotensive peptide. Plasma contains mature-type AM (m-AM), which is amidated at the carboxy terminus, and an intermediate, AM-Gly. We developed a one-step two-site IRMA specific for determining human m-AM with monoclonal antibodies. The detection limit was 0.5 pmol/L, and the working range (CV <15%) was 1-300 pmol/L. Dilution of plasma samples showed good linearity. The recovery of added AM was 91-118%. The intra- and interassay imprecision values (CVs) were 4.4-8.2% and 5.5-8.3%, respectively. The assay had no cross-reactivity with AM-Gly or other peptides similar to AM. The mean (+/- SD) plasma human m-AM concentration of 61 healthy subjects was 1.18 +/- 0.65 pmol/L. In conclusion, our IRMA makes it possible to specifically measure m-AM, using a small amount of plasma sample (0.2 mL) by a one-step overnight assay without prior extraction. Our simplified method would be suitable for clinical studies on AM, especially when large numbers of samples must be processed.

Adrenomedullin↗
PubMed1998

Structure-function studies of human leptin.

To elucidate the structural requirement of human leptin for its functions, the wild-type, mutant-type, C-terminal deletion, and N-terminal deletion were expressed in Escherichia coli and purified in soluble forms. These leptin analogs were intracerebroventrically injected into C57BL/6J ob/ob mice, and their in vivo biological activities were evaluated. The mutant-type leptin lacking a C-terminal disulfide bond reduced food intake at doses of more than 15 pmol/mouse, which was as effective as the wild-type leptin. C-terminal deletion without the loop structure, also significantly, but to a lesser extent, reduced food intake at doses of more than 90 pmol/mouse. However, N-terminal deletions showed no effect on food intake. We also evaluated the effects of the leptin analogs on radiolabeled leptin binding to its receptor in the choroid plexus using autoradiography. An excess of unlabeled mutant-type leptin as well as wild-type leptin led to complete inhibition of binding. C-terminal deletions led to weak inhibitory activity, whereas N-terminal deletions caused no inhibitory activity. These results clearly demonstrate that the N-terminal region of leptin is essential for both its biological and receptor binding activities. The amino acid sequence of the C-terminal loop structure is also important for enhancing these actions, whereas the C-terminal disulfide bond is not needed.

Animals↗
PubMed1998

Novel B-ring modified combretastatin analogues: syntheses and antineoplastic activity.

A series of B-ring modified combretastatin analogues were synthesized and their inhibitory activity against microtubule assembly, cytotoxic activity against Colon 26 adenocarcinoma cancer cell line were evaluated. Among these, pyridone derivative (19) showed strong antimitotic activity and cytotoxicity, along with excellent water-solubility.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Syntheses and antitumor activity of cis-restricted combretastatins: 5-membered heterocyclic analogues.

A series of cis-restricted combretastatin analogues with 5-membered heterocycles were synthesized and their inhibitory activity against microtubule assembly and cytotoxic activity against the colon 26 adenocarcinoma cancer cell line were evaluated. Some of the heterocyclic analogues showed potent antitubulin activity and cytotoxicity. Compounds 16 and 35 showed marked tumor growth suppression in the colon 26 murine tumor model.

Animals↗
PubMed1998

Novel combretastatin analogues effective against murine solid tumors: design and structure-activity relationships.

A series of combretastatin A-4 (CA-4) analogues were synthesized, and their cytotoxic effects against murine Colon 26 adenocarcinoma and inhibitory activity on tubulin polymerization were evaluated. Since CA-4 has limited aqueous solubility, the target compounds were designed to improve solubility by introduction of a nitrogen-containing group. Among the compounds synthesized, those with an amino moiety in place of the phenolic OH of CA-4 showed potent antitubulin activity and cytotoxicity against murine Colon 26 adenocarcinoma in vitro. Some of the compounds which were potent in vitro were evaluated in the murine tumor model Colon 26 in vivo. Among these, 13bHCl, 21aHCl, and 21bHCl showed significant antitumor activity in the animal model, while CA-4 was ineffective. 13bHCl and 21aHCl were further evaluated in two murine tumor models (Colon 38 and 3LL) and human xenografts HCT-15. These compounds showed potent antitumor activity comparable or superior to that of CDDP. The structure-activity relationships of this series of compounds are also discussed.

Acrylonitrile↗
PubMed1998

Reduction of ornithine decarboxylase antizyme (ODC-Az) level in the 7,12-dimethylbenz(a)anthracene-induced hamster buccal pouch carcinogenesis model.

Ornithine decarboxylase (ODC) activity is elevated in and necessary for oral carcinogenesis, but the mechanism for its deregulation is unclear. Using subtractive hybridization, a 1029 bp full-length cDNA encoding a 222 amino acid open reading frame has been isolated from normal hamster oral keratinocytes. The hamster cDNA is homologous to the human, mouse and rat ornithine decarboxylase antizyme gene (ODC-Az). The hamster ODC-Az gene demonstrated a restriction fragment length polymorphism (RFLP) upon Southern blot analysis comparing normal and tumor hamster genomic DNA. Northern blot analysis revealed that normal hamster oral keratinocytes express readily detectable level of ODC-Az mRNA. Malignant oral keratinocytes demonstrate reduced expression of the ODC-Az mRNA. In contrast, malignant hamster oral keratinocytes have elevated ODC mRNA levels and lengthened ODC protein half-life when compared to the normal counterparts. This was corroborated by direct measurement of ODC enzymatic activity. These data support the hypothesis that the reduced and/or loss of expression and function of the ODC-Az gene is an important event for the early de-regulation of cellular proliferation during oral tumor development.

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

IL-4-dependent regulation of TGF-alpha and TGF-beta1 expression in human eosinophils.

TGFs play important roles in wound healing and carcinogenesis. We have previously demonstrated that eosinophils infiltrating into different pathologic processes elaborate TGF-alpha and TGF-beta1. Eosinophils infiltrating hamster cutaneous wounds were found to express TGFs sequentially. In this study, we examined the biologic mediators that may regulate the expression of TGF-alpha and -beta1 by eosinophils. Eosinophils were isolated from the peripheral blood of healthy donors and cultured in the absence or presence of IL-3, IL-4, and IL-5. Cells were analyzed by in situ hybridization and immunohistochemistry. Supernatants from these cultures were assayed for secreted TGF-alpha and TGF-beta1 using TGF-specific ELISAs. IL-3, IL-4, and IL-5 independently up-regulated TGF-beta1 mRNA and product expression by eosinophils in all donors. Interestingly, TGF-alpha production by eosinophils was up-regulated by IL-3 and IL-5 but was down-regulated by IL-4. Consistent with the ability of IL-4 to regulate eosinophil responses, IL-4 signaling molecules are present in human eosinophils. The observation that IL-4 can differentially regulate the expression of TGF-alpha and TGF-beta1 suggests that IL-4 may serve as a physiologic molecular switch of TGF expression by the infiltrating eosinophils in wound healing and carcinogenesis.

Adult↗
PubMed1998

Transforming growth factor-beta 1 stimulates or inhibits cell growth via down- or up-regulation of p21/Waf1.

Transforming growth factor-beta (TGF-beta) regulates cell proliferation positively or negatively. The mitoinhibition by TGF-beta has been attributed to induction of cyclin-dependent kinase (CDK) inhibitors, such as p15/ Ink4B, p27/Kip1, and p21/Waf1 also known as Cip1 and Sdi1. However, the biological process by which TGF-beta exerts the stimulatory effects on cell growth remains poorly understood. Here we report that TGF-beta 1 stimulates DNA synthesis of IMR-90 human embryonic lung fibroblasts but inhibits that of HuCCT1 human cholangiocarcinoma cells, via down- or up-regulation of p21/Waf1, respectively. TGF-beta 1 markedly suppresses IMR-90 cells to express two different kinds of the p21/Waf1 gene transcription factors, the p53 tumor suppressor and the interferon regulatory factor-1 (IRF-1). This is followed by a marked decrease in expression of p21/Waf1 in a manner consistent with the timing of activation of cyclin E-associated kinase, which normally accompanies the G1-S transition in the cell cycle. Contrarily, TGF-beta 1-induced inhibition of DNA synthesis in HuCCT1 cells is preceded by IRF-1-dependent but p53-independent up-regulation of p21/Waf1 expression followed by inactivation of cyclin E-associated kinase. Thus the cell growth stimulation or inhibition by TGF-beta 1 are mediated by the down- or up-regulation of p21/ Waf1, respectively.

CDC2-CDC28 Kinases↗
PubMed1998

m-Calpain (calcium-activated neutral proteinase) in Alzheimer's disease brains.

An antibody specific for the calpain isoform m-calpain was used to resolve conflicting results from several studies on the possible role of m-calpain in the pathogenesis of Alzheimer's disease (AD). Levels of the enzyme in both cytosolic and membranous fractions of brain tissue were determined by Western blot analysis. We also demonstrated changes in m-calpain molecules in AD brains using high-resolution 2D gel electrophoresis (2DE). The levels of the m-calpain isoform detected in the cytosolic fraction were significantly increased in AD brains when compared with the levels in controls. On 2DE, m-calpain molecules resolved into eight main spots. These spots were detected in AD brains as well as in control brains, suggesting that the calpain molecule was not qualitatively changed in AD. Quantitative analysis of the m-calpain spots on 2DE, on the other hand, indicated that the ratio of the intensity of four protein spots in the acidic region to that of the total spots was increased in AD brains.

Aged↗
PubMed1998

Synthesis and antiviral activity of novel acyclic nucleosides: discovery of a cyclopropyl nucleoside with potent inhibitory activity against herpesviruses.

A series of acyclic nucleosides with two hydroxymethyl groups mimicking the 3'- and 5'-hydroxyl groups of the 2'-deoxyribose moiety were prepared and evaluated for their antiherpetic activity. Among those, 9-[[cis-1', 2'-bis(hydroxymethyl)cycloprop-1'-yl]methyl]guanine (3) showed extremely potent antiviral activity against herpes simplex virus type-1 (HSV-1) with good selectivity. Both enantiomers of 3 were synthesized starting from chiral epichlorohydrins, and only one of the enantiomers with 1'S,2'R-configuration (3a) exhibited strong antiherpetic activity (IC50 of 0.020 microg/mL against HSV-1 Tomioka vs 0.81 microg/mL for acyclovir). Enantiomer 3a was also more inhibitory than acyclovir against varicella-zoster virus (VZV) but ineffective against human immunodeficiency virus (HIV). Compound 3a is phosphorylated by HSV-1 thymidine kinase (TK) very efficiently. The relationship between conformation and antiherpetic activity in this series of compounds is discussed.

Acyclovir↗
PubMed1998

Ubiquitous presence of cellular proteins that specifically bind to the 3' terminal region of hepatitis C virus.

The 3' terminal region (3'-X tail) of hepatitis C virus (HCV) genomic RNA forms a stable stem-loop structure. The 3'-X tail consists of 98 nucleotides (nt) that are highly conserved among the HCV strains and supposed to function as a cis-acting region for replication of negative strand RNA and/or viral encapsidation. In the present study, by UV cross-linking assay we found two kinds of cellular proteins of approximately 87 and 130 kDa, which specifically bind to the full-length 3'-X tail (nt 1 to 98), but not the 3'- or 5'-truncated 3'-X tail, consisting of nt 1 to 50 or nt 51 to 98, respectively. These proteins were detected in human cell lines such as hepatic tumor cell lines and a T-lymphocyte cell line and also in a human embryonic lung fibroblast cell strain. In addition, human hepatocellular carcinoma tissues expressed these proteins regardless of infection or uninfection of HCV. Furthermore, these proteins were also detected in normal human tissues derived from the lung, heart, kidney, stomach, intestine, and colon. Thus, these cellular proteins, which are ubiquitously present in human tissues, might be involved in viral replication and/or encapsidation.

Binding Sites↗
PubMed1998

Cloning, mapping, expression, function, and mutation analyses of the human ortholog of the hamster putative tumor suppressor gene Doc-1.

doc-1 is a putative tumor suppressor gene isolated and identified from the hamster oral cancer model. Here, we report the molecular cloning and the functional characterization of the human ortholog of the hamster doc-1 gene. Human doc-1 cDNA is 1.6 kilobase pairs in length and encodes for a 115-amino acid polypeptide (12.4 kDa, pI 9. 53). Sequence analysis showed 98% identity between human and hamster doc-1 protein sequences. DOC-1 is expressed in all normal human tissues examined. In oral keratinocytes, expression of DOC-1 is restricted to normal oral keratinocytes. By immunostaining of normal human mucosa, DOC-1 is detected in both the cytoplasm and nuclei of basal oral keratinocytes; while in suprabasilar cells, it is primarily found in the nuclei. Human oral cancers in vivo did not exhibit immunostaining for DOC-1. Like murine DOC-1, human DOC-1 associates with DNA polymerase alpha/primase and mediates the phosphorylation of the large p180 catalytic subunit, suggesting it may be a potential regulator of DNA replication in the S phase of the cell cycle. Using a human doc-1 cosmid as a probe, human doc-1 is mapped to chromosome 12q24. We identified four exons in the entire human doc-1 gene and determined the intron-exon boundaries. By polymerase chain reaction and direct sequencing, we examined premalignant oral lesion and oral cancer cell lines and found no intragenic mutations.

Amino Acid Sequence↗