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Biomedical subjects

T Taniguchi

Publications and source records attributed to T Taniguchi.

At least 271 records · Page 15Linked to original sources
PubMed1998

A critical role for cyclin C in promotion of the hematopoietic cell cycle by cooperation with c-Myc.

Cyclin C, a putative G1 cyclin, was originally isolated through its ability to complement a Saccharomyces cerevisiae strain lacking the G1 cyclin gene CLN1-3. Unlike cyclins D1 and E, the other two G1 cyclins obtained by the same approach and subsequently shown to play important roles during the G1/S transition, there is thus far no evidence to support the hypothesis that cyclin C is indeed critical for the promotion of cell cycle progression. In BAF-B03 cells, an interleukin 3 (IL-3)-dependent murine pro-B-cell line, cyclin C gene mRNA was induced at the G1/S phase upon IL-3 stimulation and reached a maximal level in the S phase. Enforced expression of exogenous cyclin C in this cell line failed to alter its growth properties. In the present study, we examined whether cyclin C is capable of cooperating with the cytokine-responsive immediate-early gene products c-Myc and c-Fos in the promotion of cell proliferation. We found that cyclin C is able to cooperate functionally with c-Myc, but not c-Fos, to induce both BAF-B03 cell proliferation in a cytokine-independent fashion and the formation of cell clusters. Furthermore, cyclin C was primarily responsible for the induction of cdc2 gene expression. Our data define a novel role for cyclin C in the regulation of both the G1/S and G2/M phases of the cell cycle, and this effect appears to be independent of the activity of CDK8 in the control of transcription.

Animals↗
PubMed1998

Tyrosine phosphorylation and association of p130Cas and c-Crk II by ANG II in vascular smooth muscle cells.

In cultured vascular smooth muscle cells (VSMC), angiotensin II (ANG II) stimulated tyrosine phosphorylation of multiple proteins including a 130-kDa protein. This 130-kDa protein was identified as a Crk-associated substrate, p130Cas. ANG II-stimulated tyrosine phosphorylation of p130Cas was rapid, concentration dependent, and inhibited by the AT1-receptor antagonist CV-11974. Neither downregulation of protein kinase C by long exposure of cells to phorbol 12,13-dibutyrate nor blockade of Ca2+ mobilization by 1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester had an effect on ANG II-stimulated tyrosine phosphorylation of p130Cas. Stimulation with ANG II enhanced the specific association of p130Cas with c-Crk II. The time course of the association of p130Cas and c-Crk II was similar to that of tyrosine phosphorylation of p130Cas. c-Crk II was also tyrosine phosphorylated in response to ANG II. These results indicate that ANG II induces tyrosine phosphorylation of p130Cas and c-Crk II and their specific association, suggesting a potential role of the p130Cas-c-Crk II complex in ANG II signal transduction in VSMC.

Angiotensin II↗
PubMed1998

Protective effect of talipexole on MPTP-treated planarian, a unique parkinsonian worm model.

The planarian, a flatworm, has a high potential for regeneration, and dopamine plays a key role in its behavior. Planarians treated with MPTP underwent autolysis and individual death in a concentration-dependent manner. When the planarian body was cut into anterior, middle and posterior pieces, each piece subsequently regenerated and reorganized to form a new individual within approximately 10 days. The anterior piece was significantly more sensitive than the middle and posterior pieces to MPTP cytotoxicity. Concomitant treatment with talipexole, an anti-parkinsonian drug, inhibited MPTP-induced autolysis and individual death in a concentration-dependent manner. Pramipexole showed a similar protective effect. In addition, post-treatment with talipexole at 1 hr after MPTP completely inhibited MPTP-induced individual death. Although MPTP treatment caused 30% of the planarians to undergo autolysis and individual death within 12 hr, post-treatment with talipexole even at 12 hr completely rescued the remaining 70% of the planarians from death. These results suggest that the MPTP-treated planarian may be useful as a novel parkinsonian model in which talipexole has a protective effect even in the case of post-treatment.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1998

Tamsulosin: alpha1-adrenoceptor subtype-selectivity and comparison with terazosin.

Selectivity of tamsulosin and terazosin to functional alpha1-adrenoceptors was examined. Both drugs competitively inhibited the contractile responses to noradrenaline in different tissues where the responses were mediated through the alpha1D-, alpha1B- or alpha1L-subtype. Together with the affinities obtained in the binding study with cloned (alpha1a, alpha1b, alpha1d) and native (alpha1A and alpha1B) subtypes, the selectivity of tamsulosin was alpha1A>alpha1L, alpha1D>alpha1B. Terazosin had lower affinity at various subtypes than tamsulosin, but showed relatively high selectivity to the alpha1D-subtype. In the human prostate, tamsulosin was more than 30-fold higher in affinity than terazosin in functional and binding studies.

Adrenergic alpha-Antagonists↗
PubMed1998

Effects of peptidase inhibitors on the enkephalin-induced anti-nociception in rats.

The intra-third-ventricular (i.t.v.) administration of [Met5]-enkephalin (enk) to rats pretreated i.t.v. with three peptidase inhibitors (PIs), amastatin, captopril and phosphoramidon, inhibited the tail-flick response. The enk-induced inhibition was augmented by increasing the doses of the three PIs, with the maximum inhibition being attained at the doses of 10 nmol each. The enk-induced inhibition in rats pretreated with any combination of two PIs, however, were markedly smaller than that in rats pretreated with all three PIs, indicating that three kinds of enzymes all played important roles in the inactivation of enk. The inhibitory effect of enk on the tail-flick response in rats pretreated with the three PIs at doses of 10 nmol each was approximately tenfold higher than that of morphine. The relative anti-nociceptive potencies of enk and morphine were similar to the relative inhibitory potencies obtained previously with the isolated guinea pig ileum pretreated with the three PIs, indicating that the hydrolysis of the i.t.v. administered enk was largely prevented by the three PIs. However, the magnitude of the enk-induced inhibition in rats pretreated s.c. with the three PIs indicated that the hydrolysis of enk injected i.t.v. was not largely prevented by the s.c. administration of three PIs at doses up to 10 micromol each/kg.

Animals↗
PubMed1998

Hemagglutination with crane herpesvirus.

A crane herpesvirus (CrHV) grown in chicken embryo fibroblast (CEF) cells was tested for hemagglutination (HA) with erythrocytes from a variety of species at 4 degrees C, room temperature and 37 degrees C. HA was observed at all temperatures with erythrocytes from mouse, ddY and BALB/c strains, but not with those from cattle, sheep and chicken. Mice, ddY strain, showed an individual variation in agglutinability of their erythrocytes and erythrocytes from BALB/c gave a higher HA titer. The HA activity was inhibited by the sera obtained from naturally infected cranes, experimentally infected duck and immunized rabbit with CrHV. HI antibody titers of these sera showed a closely positive correlation with their neutralizing antibody titers.

Animals↗
PubMed1998

Significance of circulating hepatocyte growth factor level as a prognostic indicator in primary breast cancer.

The circulating hepatocyte growth factor (HGF)/scatter factor level is frequently increased in advanced cancer patients. In this study, we have assessed the prognostic value of the circulating HGF level determined by enzymatic immunoassay in primary breast cancer patients. Of 200 primary breast cancer patients, 54 (27.0%) showed the increase of serum HGF level according to the age-matched cutoff values. The prognosis of the patients with the increased HGF level was statistically worse than that of the patients with normal HGF level (P = 0.0001, log-rank test). Multivariate analysis confirmed that the increase in HGF level was an independent prognostic indicator in primary breast cancer patients. In the background analysis, the increase in serum HGF level was significantly associated with tumor size, nodal status, and histological evidence of venous invasion. The data indicate that up-regulation of the circulating HGF level may predict systemic tumor spread and early relapse in primary breast cancer patients.

Adult↗
PubMed1998

In vitro and in vivo induction of heme oxygenase-1 in rat glial cells: possible involvement of nitric oxide production from inducible nitric oxide synthase.

To determine whether heme oxygenase-1 (HO-1) protein is induced by endogenous nitric oxide (NO) in rat glial cultures, we examined the effects of lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), and NO donors such as S-nitroso-N-acetylpenicillamine (SNAP), in mixed glial cells and in vivo rat hippocampus. In cultured glial cells, treatment with LPS induced the expression of 130-kd inducible NO synthase (iNOS) after 6 h, and NO2- accumulation and enhancement of the protein level of 33-kd HO-1 after 12 h. In addition, treatment with SNAP induced HO-1 expression after 6 h. Although NOS inhibitors such as NG-nitro-L-arginine (NNA) and NG-methyl-L-arginine did not change LPS-induced iNOS expression, these inhibitors suppressed both NO2- accumulation and the enhancement of HO-1. Immunocytochemistry showed that treatment with LPS for 24 h induced iNOS immunoreactivity predominantly in ameboid microglia, while this treatment induced HO-1-immunoreactivity in both microglia and astrocytes. In in vivo rat hippocampus, microinjection of LPS plus IFN-gamma, or SNAP after 24 h also induced HO-1 immunoreactivity in reactive microglia and astrocytes. In addition, intraperitoneal administration of NNA inhibited HO-1 immunoreactivity induced by the microinjection of LPS plus IFN-gamma. These results suggest that endogenous NO production by iNOS in microglia causes autocrine and paracrine induction of HO-1 protein in microglia and astrocytes in vitro and in rat brain.

Animals↗
PubMed1998

[Enhanced induction of apoptosis of human colorectal cancer cells after preoperative treatment with 5-fluorouracil its relationship to DNA ploidy pattern].

We examined the relationship between apoptosis induced by 5-fluorouracil (5-FU) that was given preoperatively to colorectal cancer patients and DNA ploidy pattern, and investigated the cell cycle changes, and the expression of Ki-67. Twenty-nine patients with advanced colorectal cancer were divided into four groups, 3 days, 5 days, 7 days, and 10 days. Groups received continuous intravenous 5-FU at 500 mg/body/day preoperatively. Then, patients were divided into two groups by DNA ploidy pattern, diploid(D) and aneuploid(A). Apoptotic cells were stained by the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) method. The expression of Ki-67 was examined by immunohistochemical staining. We used flow cytometry (FCM) for analysis of cell cycle distribution. Apoptosis of cancer cells was mostly increased in 7 days 5-FU administration in both D and A groups. The expression of Ki-67 was reduced according to the prolongation of the term of 5-FU administration in both D and A groups. We assessed S-phase fraction (SPF) to evaluate the cell cycle changes by 5-FU. Tumor samples of all patients after injection of 5-FU showed S-phase accumulation. The ratio of SPF (after 5-FU/before 5-FU) was the highest in the 5-day 5-FU administration group in both D and A groups. We concluded that apoptosis and S-phase accumulation were increased, and proliferative activity was decreased by preoperative 5-FU administration in colorectal cancer patients. However, there was no clear correlation between DNA ploidy pattern and these changes.

Adenocarcinoma↗
PubMed1998

[Analysis of genomic instability by fluorescence DNA sequencer].

Within the recent four years, there have been substantial advances in understanding the molecular pathogenesis of HNPCC. As one of the result of investigation, microsatellite instability has been observed in hereditary non-polyposis colorectal cancer (HNPCC) and other sporadic cancers. Moreover, there is strong supporting evidence that mismatch repair genes play a role in HNPCC. Here, we present our investigational results and discuss possible molecular mechanisms governing DNA mutation and genomic instability, leading to the development of neoplasm. We investigated replication error (RER) of 4 microsatellite markers (dinucleotide repeats) in 131 patients with colorectal cancer (10 met the criteria of HNPCC group B), using fluorescence-based DNA sequencer. We detected RER positivity (at more than two loci) in 12 of 131 patients (9.2%). PCR-SSCP and direct sequencing of the mismatch repair genes, hMSH2 and hMLH1, revealed that two patients in HNPCC group B had germline mutations of hMSH2. The fluorescence-based techniques, such as the present RER analysis do not require radioactive materials and specialized rooms, and can easily be performed in a clinical laboratory.

Colorectal Neoplasms, Hereditary Nonpolyposis↗
PubMed1998

Protection against dynorphin-(1-8) hydrolysis in membrane preparations by the combination of amastatin, captopril and phosphoramidon.

The amounts of dynorphin-(1-8) [dyn-(1-8)] and its seven hydrolysis products, Y, YG, YGG, YGGF, YGGFL, YGGFLR and YGGFLRR, were estimated after incubating dyn-(1-8) with a membrane fraction from either guinea-pig ileum or striatum for various times at 37 degrees C. The major hydrolysis products during the initial 5-min incubation were YGGFLR and Y, which indicates that dipeptidyl carboxypeptidase and aminopeptidase activities were mainly involved in the hydrolysis. After 60 min of incubation, dyn-(1-8) was completely hydrolyzed in both membrane preparations. When the ileal and the striatal preparations were incubated for 60 min in the presence of both captopril, a dipeptidyl carboxypeptidase inhibitor, and amastatin, an aminopeptidase inhibitor, 63.8 and 49.3% of dyn-(1-8), respectively, were hydrolyzed. The YGG fragment was the major hydrolysis product in both preparations. When the ileal and the striatal membrane fractions were incubated with dyn-(1-8) in the presence of three peptidase inhibitors, captopril, amastatin and phosphoramidon (an inhibitor of endopeptidase-24.11), approximately 95% of the opioid octapeptide remained intact in both cases. This shows that dyn-(1-8) was almost exclusively hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive dipeptidyl carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. Additionally, the Ke (equilibrium dissociation constant) values of selective antagonists against dyn-(1-8) and its initial main hydrolysis product YGGFLR in two isolated preparations pretreated with the three peptidase inhibitors indicate that the latter acts on mu receptors in guinea pig ileum but delta receptors in mouse vas deferens and the former acts on kappa receptors in both preparations. It is indicated, therefore, that in the absence of peptidase inhibitors endogenously released dyn-(1-8) acts either through dyn-(1-8) itself on kappa receptors or through YGGFLR on mu or delta receptors depending on both the three peptidase activities and the three receptor type densities at the target synaptic membrane.

Animals↗
PubMed1998

Regulation of the interferon system, immune response and oncogenesis by the transcription factor interferon regulatory factor-1.

Interferon regulatory factor-1 (IRF-1) is a transcriptional activator which was originally identified as the regulator of the type I interferon (IFN-alpha/beta) gene expression. Subsequent studies have revealed that IRF-1 is involved in a wide spectrum of the host defense mechanisms, including the antiviral response by IFNs. IRF-1 has also been shown to regulate a variety of cytokines and their target genes, thereby contributing to the development and function of the Th1-type immune response. Furthermore, IRF-1 is a critical regulator of cell growth and death, and its inactivation accelerates cell transformation. IRF-1 may be a prototypical example of a transcription factor which can selectively modulate distinct sets of genes depending on the cell type and/or nature of the cellular stimuli, so as to evoke appropriate response in each.

Animals↗
PubMed1998

[A case of leiomyosarcoma of the jejunum with postoperative hepatic encephalopathy].

We report a case of leiomyosarcoma of the jejunum with postoperative hepatic encephalopathy. A 60-year-old man was operated for tumor of the abdomen. He was diagnosed as leiomyosarcoma of the jejunum with disseminated peritoneal metastasis, but no liver metastasis and cirrhosis. A palliative resection of the jejunum was performed. After operation, disturbance of orientation and apraxia with electroencepharographic abnormality and hyperammonemia developed. He was diagnosed as hepatic encephalopathy without lesion of the liver, and died 11 months after surgery. We consider that the portosystemic shunt and bleeding from the digestive tract due to invasion of metastatic lesions caused hepatic encephalopathy.

Hepatic Encephalopathy↗
PubMed1998

[Anesthetic management of total en bloc spondylectomy].

We analyzed the anesthetic management of 20 patients with total en bloc spondylectomy (TES) for solitary spinal metastases. Anesthesia was maintained with isoflurane, nitrous oxide in oxygen, and fentanyl in all patients. The duration of anesthesia was 733 minutes, and the amount of bleeding was 5371 ml on the average. During operation, hypovolemic shock occurred in 5 cases and huge hemothorax in 4 cases. Postoperative, huge hemothorax occurred in 6 cases and severe pneumonia in 3 cases. Maintenance of hemodynamic and respiratory function is important in perioperative management of TES.

Adult↗
PubMed1998

Protective effects of the antiparkinsonian drugs talipexole and pramipexole against 1-methyl-4-phenylpyridinium-induced apoptotic death in human neuroblastoma SH-SY5Y cells.

Treatment of human neuroblastoma SH-SY5Y cells with 1 mM 1-methyl-4-phenylpyridinium (MPP+) for 3 days induced production of reactive oxygen species (ROS), followed by caspase-3 activation, cleavage of poly(ADP-ribose) polymerase (PARP), and apoptotic cell death with DNA fragmentation and characteristic morphological changes (condensed chromatin and fragmented nuclei). Simultaneous treatment with 1 mM talipexole slightly inhibited the MPP+-induced ROS production and apoptotic cell death. In contrast, pretreatment with 1 mM talipexole for 4 days markedly protected the cells against MPP+-induced apoptosis. However, this protective effect might not be mediated by dopamine receptors. The talipexole pretreatment induced an increase in antiapoptotic Bcl-2 protein level but had no effect on levels of proapoptotic Bax, Bak, and Bad. It also inhibited MPP+-induced ROS production, p53 expression, and cleavages of caspase-3 and PARP. Similarly, pramipexole pretreatment increased Bcl-2 and inhibited MPP+-induced apoptosis. Although pretreatment with bromocriptine also had a protective effect against MPP+-induced apoptosis, it had no effect on the protein levels of Bcl-2 family members. On the other hand, N6,2'-O-dibutyryl cAMP or calphostin C induced a decreased Bcl-2 level and enhanced MPP+-induced cell death. These results suggest that talipexole has dual actions: (1) it directly scavenges ROS, affording slight protection against MPP+-induced apoptosis, and (2) it induces Bcl-2 expression, thereby affording more potent protection, if it is administrated before MPP+. Pramipexole has similar effects, whereas bromocriptine seems to exhibit the former but not the latter effect.

1-Methyl-4-phenylpyridinium↗
PubMed1997

Purification and characterization of 25-hydroxyvitamin D3 1alpha-hydroxylase from rat kidney mitochondria.

We purified extensively 25-hydroxyvitamin D3 1alpha-hydroxylase (calcidiol, NADPH: oxygen oxidoreductase (1-hydroxylating), EC 1.14.13.13) from kidney mitochondria of rachitic rats and disclosed its peculiar properties as a P450. The final preparation was identified as a 55 kDa protein having an intense absorption at 417 nm characteristic of P450. The specific activity was 4.8 nmol/min/mg of protein indicating a 350-fold purification. Specific content of P450 was 1.1 nmol/mg of protein and turnover number was 4.4 min-1.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗