Biomedical subjects

Takashi Morimoto

Publications and source records attributed to Takashi Morimoto.

15 recordsLinked to original sources

PubMed2007

Voltage-sensitive oxonol dyes are novel large-conductance Ca2+-activated K+ channel activators selective for beta1 and beta4 but not for beta2 subunits.

The large-conductance Ca(2+)-activated K(+) (BK) channel is activated by both the increase of intracellular Ca(2+) concentration and membrane depolarization. The BK channel plays crucial roles as a key molecule in the negative feedback mechanism regulating membrane excitability and cellular Ca(2+) in various cell types. Here, we report that a widely used slow-response voltage-sensitive fluorescent dye, bis(1,3-dibutylbarbituric acid)trimethine oxonol [DiBAC(4)(3)], is a potent BK channel activator. The application of DiBAC(4)(3) at concentrations of 10 nM and higher significantly increased whole-cell BK channel currents in human embryonic kidney 293 cells expressing rat BK channel alpha and beta1 subunits (rBKalphabeta1). In the presence of 300 nM DiBAC(4)(3), the activation voltage of the BK channel current shifted to the negative direction by approximately 30 mV, but the single-channel conductance was not affected. DiBAC(4)(3) activated whole-cell rBKalphabeta1 and rBKalphabeta4 currents in the same concentration range but partially blocked rBKalphabeta2 currents. The BK channel alpha subunit alone and some other types of K(+) channels examined were not markedly affected by 1 microM DiBAC(4)(3). Structure-activity relationship analyses revealed that a set of oxo- and oxoanion-moieties in two 1,3-dialkylbarbituric acids, which are conjugated by oligomethine, is the novel skeleton for the beta-subunit-selective BK channel-opening property of DiBAC(4)(3) and related oxonol compounds. This conjugated structure may be located stereochemically in one plane. These findings provide a molecular and structural basis for understanding the regulatory mechanism of BK channel activity by an auxiliary beta subunit and will be fundamental to the development of beta-selective BK channel openers.

Animals↗

PubMed2006

Activation of p38 MAPK and/or JNK contributes to increased levels of VEGF secretion in human malignant glioma cells.

Malignant gliomas are typically angiogenic and secrete high levels of VEGF. Hypoxia has been identified as an important regulator of VEGF. However, malignant gliomas express high levels of VEGF in both hypoxic perinecrotic and vital tumor areas. In this study, we examined intracellular signaling pathways involved in the secretion of VEGF in glioma cells under normoxic conditions. Human malignant glioma cell lines, T98G, U373MG, U87MG, and A172, and human fetal lung fibroblasts (HFL) were cultured both with and without IL-1beta under normoxic conditions. VEGF, IL-1, IL-6, and TNF-alpha were measured with ELISA. VEGF mRNA levels were estimated by RT-PCR. Inhibitors of COX-2, MAPK, and phosphatidyl inositol 3-kinase (PI3-K), and blocking antibodies to TGF-beta II and TNF-alpha, or IL-1 receptor antagonist, were used to examine their effects on VEGF secretion. Phosphorylation of MAPK was examined by immunoblotting. The basal levels of VEGF secretion were significantly higher in U87MG, U373MG, and T98G, than HFL. IL-1beta significantly stimulated VEGF secretion in these glioma cells. Inhibitors of p38 MAPK and/or JNK significantly suppressed VEGF secretion both in the presence and absence of IL-1beta, while inhibitors of COX-2, ERK1/2, and PI3-K did not. Constitutive phosphorylation of p38 MAPK and JNK was observed in these glioma cells. The levels of IL-1beta in U87MG were significantly higher than in other glioma cell lines, and IL-1 receptor antagonist suppressed basal secretion of VEGF from U87MG. In conclusion, p38 MAPK and JNK pathways play an important role in VEGF secretion from malignant glioma cells under normoxic conditions, possibly contributing to VEGF-induced angiogenesis in malignant gliomas at vital tumor areas where there is no hypoxia.

Brain Neoplasms↗

PubMed2005

The significance of the intraoperative repeated dosing of antimicrobials for preventing surgical wound infection in colorectal surgery.

PURPOSE: It is widely accepted that antimicrobial prophylaxis is useful for the prevention of surgical wound infection, especially in colorectal surgery. While many reports support the finding that the first dose should be administered immediately before surgery, there is less evidence concerning the ideal timing for the second dose. The purpose of this study is to examine the significance of intraoperative repeated dosing. METHODS: A surgical series of 131 patients with primary colorectal cancer was retrospectively analyzed for 14 parameters, including the protocols of antimicrobial administration to determine the clinical risk factors for surgical wound infection. RESULTS: The overall surgical wound infection rate of the 131 patients was 16.0% (21/131). When the operation finished within 4 h after the first dose (n = 29), wound infection was observed in only one patient (3.4%). In a prolonged operation exceeding 4 h after the first dose, the surgical wound infection rates were 8.5% and 26.5%, respectively, for those with (n = 47) and without (n = 49) intraoperative repeated dosing, which were significantly different based on both a univariate analysis (P = 0.031) and a multivariate analysis (P = 0.0079). CONCLUSION: Intraoperative repeated antimicrobial dosing is therefore recommended to prevent the surgical wound infection for prolonged colorectal surgery.

Aged↗

PubMed2004

Reconstruction of a high-resolution image on a compound-eye image-capturing system.

The authors have proposed an architecture for a compact image-capturing system called TOMBO (thin observation module by bound optics), which uses compound-eye imaging for a compact hardware configuration [Appl. Opt. 40, 1806 (2001)]. The captured compound image is decomposed into a set of unit images, then the pixels in the unit images are processed with digital processing to retrieve the target image. A new method for high-resolution image reconstruction, called a pixel rearrange method, is proposed. The relation between the target object and the captured signals is estimated and utilized to rearrange the original pixel information. Experimental results show the effectiveness of the proposed method. In the experimental TOMBO system, the resolution obtained is four times higher than that of the unit image that did not undergo reconstruction processing.

Journal Article↗

PubMed2004

Impairment of both apoptotic and cytoprotective signalings in glioma cells resistant to the combined use of cisplatin and tumor necrosis factor alpha.

PURPOSE: Tumor necrosis factor (TNF)-alpha elicits two opposing effects, the induction of apoptosis and the transcription of antiapoptotic genes. We have recently shown that cisplatin sensitizes glioma cells to TNF-induced apoptosis, but only in some cell lines. To understand the mechanism involved in the different susceptibilities, we examined both the activation of caspases and cytoprotective signaling by TNF-alpha. EXPERIMENTAL DESIGN: Caspase activation was examined by estimating the cleavage of substrate peptides and by immunoblot to identify the cleavage of procaspases. Peptide inhibitors of caspases were used to reverse the cytotoxicity. The binding of TNF-alpha to the receptor was analyzed by flow cytometry. Nuclear factor (NF)-kappaB activation was assayed by the binding of NF-kappaB to oligonucleotides containing the consensus binding site. Interleukin (IL)-1beta, IL-6, IL-8, and manganous superoxide dismutase (MnSOD) were measured by enzyme-linked immunoassays. RESULTS: T98G and U87MG underwent apoptosis on treatment with cisplatin and TNF-alpha, but U373MG and A172 were resistant. Caspases 2, 3, and 6-10, but not caspases 1, 4, and 5, were activated in sensitive cells, and none were activated in resistant cells. The binding of TNF-alpha to the receptor was the same in all four of the cell lines. In the sensitive cells, NF-kappaB activation and the production of IL-1beta, IL-6, IL-8, and MnSOD were significantly elevated by TNF-alpha. However, in the resistant cells, the production of IL-1beta and IL-6 were specifically impaired in response to TNF-alpha. CONCLUSIONS: Our results indicate that both apoptotic and cytoprotective pathways are impaired in glioma cells that are resistant to treatment with cisplatin and TNF-alpha.

Antineoplastic Agents↗

PubMed2004

Does serum CA19-9 play a practical role in the management of patients with colorectal cancer?

PURPOSE: CA19-9 is often used in combination with carcinoembryonic antigen to manage patients with colorectal cancer, even though there is insufficient evidence to support this use of CA19-9. Carcinoembryonic antigen, by contrast, has been regarded as a better indicator of poor prognosis and recurrence. The purpose of this study is to clarify whether CA19-9 is, in fact, a useful marker in the management of colorectal cancer patients by comparing it with carcinoembryonic antigen. METHODS: A retrospective investigation was done for a consecutive series of 155 patients with colorectal adenocarcinoma who underwent potentially curative surgery between 1995 and 1999. Excluded were patients with postoperative assays performed less than three times for either carcinoembryonic antigen or CA19-9 and those who had developed secondary cancers. Data from 118 patients were analyzed in terms of prediction of prognosis and detection of recurrences. RESULTS: The sensitivities of preoperative CA19-9 and carcinoembryonic antigen were 29.8 percent and 45.3 percent, respectively. In the univariate analysis of preoperative carcinoembryonic antigen and CA19-9 assays in 114 patients, high carcinoembryonic antigen level was significantly associated with poor prognosis (P = 0.0090) by log-rank test). We could not find a significant association between preoperative CA19-9 abnormality and survival (P = 0.12). Multivariate analysis of preoperative factors indicated significance in TNM stage (P = 0.0094) and tumor location (P = 0.036) but in neither carcinoembryonic antigen (P = 0.061) nor CA19-9 (P = 0.22). Among 40 patients with recurrences, postoperative elevations of tumor markers were seen in 19 cases for CA19-9 and in 37 for carcinoembryonic antigen throughout the follow-up periods. Sensitivity, specificity, positive predictive value, and negative predictive value were 0.48, 0.88, 0.68, and 0.77, respectively, for CA19-9, and 0.93, 0.88, 0.80, and 0.96, respectively, for carcinoembryonic antigen. In patients with recurrences, the initial postoperative elevation of tumor markers was seen earlier than the detection of recurrence in 68.4 percent of those with CA19-9 elevation and in 67.6 percent of those with carcinoembryonic antigen elevation. There was only one patient with recurrence who had CA19-9 elevation without carcinoembryonic antigen elevation, while 19 recurrent patients had carcinoembryonic antigen elevation without CA19-9 elevation. Multivariate analysis showed a significant risk of carcinoembryonic antigen elevation against recurrence with an odds ratio of 32.0 (P < 0.0001), in contrast to an insignificant association of CA19-9 elevation (P = 0.23). CONCLUSION: We could not find clinical significance to support the use of CA19-9 to predict the prognosis and detect recurrence of colorectal cancer. Because of this, we do not recommend routine use of CA19-9 in staging and surveillance of colorectal cancer patients.

Adenocarcinoma↗

PubMed2004

Molecular characterization of two highly homologous receptor-like kinase genes, RLK902 and RKL1, in Arabidopsis thaliana.

Receptor-like kinases (RLKs) constitute a large family of signal perception molecules. We characterized two highly homologous RLK genes, RLK902 and RKL1, in Arabidopsis. RLK902 and RKL1 showed a 75% amino acid sequence identity over their entire regions. In the RLK902 pro::GUS transgenic lines, GUS activity was strong in the root tips, lateral root primordia, stipules, and floral organ abscission zones, while the RKL1 promoter activity was dominant in the stomata cells, hydathodes and trichomes of young rosette leaves, and floral organ abscission zones. Neither the rlk902 mutant line, rkl1 mutant line nor rlk902/rkl1 double-knockout mutant line showed any significant phenotypes under normal growth conditions. These results suggest that RLK902 and RKL1 might mediate the signal transduction pathway in which at least one other complementary signaling pathway to these two RLKs might exist.

Amino Acid Sequence↗

PubMed2003

Cytoplasmic complex of p53 and eEF2.

We have shown previously that cytoplasmic p53 is covalently linked to 5.8S rRNA. The covalent complex is associated with a small subset of polyribosomes, which includes polyribosomes translating p53 mRNA. Because 5.8S rRNA resides in or near the ribosomal P site, our findings suggested involvement of p53 in translational regulation. Ninety-seven kiloDaltons eEF2 was found to coimmunoprecipitate in a salt-stable complex with p53. The 97 kDa species was identified as eEF2, because it was (1) recognized by a polyclonal antiserum specific for eEF2, (2) ADP-ribosylated by diphtheria toxin (DT), and (3) radiolabeled by gamma-32P-azido-GTP and UV-irradiation. p53 and eEF2 sedimented in sucrose gradients in both polyribosomal and subribosomal fractions. Subribosomal p53 can bind eEF2 without the mediation of ribosomes, because (1) it binds subribososomal eEF2, (2) it binds phosphorylated eEF2, and (3) subribosomal p53-bound eEF2 can be ADP-ribosylated by DT. No effect of p53 activation was found on eEF2 expression or phosphorylation. However, the binding of eEF2 to p53 decreased when cytoplasmic p53 migrated to the nucleus. Renaturation of temperature sensitive A135V mutant p53 (ts-p53) was found to alter the sensitivity of p53 mRNA translation, but not bulk mRNA translation, to the translocation-specific elongation inhibitor, cycloheximide (Cx). The association of p53 with two translational components involved in ribosomal translocation, eEF2 and 5.8S rRNA, and the effect of p53 on sensitivity to the translocation inhibitor, Cx, as well as the known molecular interactions of these components in the ribosome suggest involvement of p53 in elongation.

Animals↗

PubMed2003

[A patient with stage IVb small cell carcinoma of the esophagus who survived 23 months after systemic cancer chemotherapy].

A 59-year-old male visited our hospital with complaints of difficulty in swallowing. X-ray barium studies and upper gastrointestinal endoscopic examination revealed an irregular ulcerated lesion in the lower portion of the esophagus, which was diagnosed based on pathology tests as small cell carcinoma. A computed tomography scan showed para-aortic lymph node swelling and multiple liver metastases. Treatment with chemotherapy of CDDP and 5-FU showed clinical complete remission. However, the patient died of paraaortic lymph node metastasis, recurrence of the original lesion, multiple liver metastasis and brain metastasis 23 months after diagnosis. The prognosis of small cell carcinoma of the esophagus is quite unfavorable because of the highly aggressive biological behavior. However, if remission is achieved by chemotherapy as in this case, a better prognosis is possible.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed2003

[Long-term prognosis of patients with local recurrence of breast cancer].

From 1985 to 2002, 22 patients with local recurrence after radical mastectomy have been treated in our hospital. Resection was possible in 9 patients. We evaluated long-term prognosis of the 9 patients. The observation interval from first recurrence was 17-207 months (median 91.5 months). Five of the 9 experienced recurrence again. Opposite axillary lymph node metastasis was observed in 2, bone metastasis in 1, liver metastasis in 1, and lung metastasis in 1. Disease free interval (DFI) until the first recurrence of patients with a second recurrence was 69-100 months (median 90 months). The interval from first recurrence to second recurrence was 46-108 months (median 60 months). Each second recurrence occurred within double the DFI until the first recurrence. For all of the patients in which a second recurrence was not observed, the observed interval was shorter than the DFI until first recurrence. Local recurrence should be considered systemic disease. Many of the patients who underwent resection of the local recurrence experienced a second recurrence after longer observation. We believe that patients with local recurrence should be observed for a period of about double the DFI.

Adult↗

PubMed2002

An increase in urinary nitrite/nitrate excretion is associated with the hyperdynamic state after cardiovascular surgery.

OBJECTIVES: To test the hypotheses (1) that nitric oxide (NO) production is stimulated after cardiovascular surgery and is related to the hyperdynamic state and (2) that NO production is more prominent in patients with cardiopulmonary bypass. DESIGN: Prospective, clinical study. SETTING: Intensive care unit in a university hospital. PATIENTS: One hundred patients after cardiovascular surgery: coronary artery bypass graft with (n=53) and without (n=17) cardiopulmonary bypass, valve surgery with cardiopulmonary bypass (n=23) and thoracic aortic replacement with cardiopulmonary bypass (n=7). INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Urinary nitrite/nitrate (NOx) excretion was measured by the high-performance liquid chromatography-Griess system as an index of endogenous NO production during the first 2 postoperative days. Hemodynamic variables, hematologic variables and serum C-reactive protein concentrations were measured after the operation. Urinary NOx concentrations were 146+/-70 and 190+/-93 micro mol/l, and the amounts of NOx excreted in the urine were 23+/-10 and 18+/-8 micro mol/h on the 1st and 2nd days, respectively. Urinary NOx excretions were positively correlated with the cardiac index (P<0.01), but inversely correlated with the systemic vascular resistance index (P<0.01). Urinary NOx concentrations were positively correlated with serum C-reactive protein concentrations (P<0.01), but inversely correlated with the cardiopulmonary bypass time (P<0.01). The urinary NOx concentration was highest in patients undergoing coronary artery bypass graft without cardiopulmonary bypass. CONCLUSION: These findings suggest, firstly, that NO production is stimulated by a surgical inflammatory response and, secondly, that the endogenous NO contributes to the increase in cardiac output that accompanies the reduced systemic vascular resistance after cardiovascular surgery.

Aged↗

PubMed2002

Effects of partial suppression of ribosomal protein S6 on organ formation in Arabidopsis thaliana.

An expression library of Arabidopsis thaliana cDNAs was randomly introduced into A. thaliana. The transformant pool was used to obtain a line, c105, with reduced apical dominance and irregular positioning of leaves and flowers. The inserted DNA was a 3'-fragment of the ribosomal protein S6 gene with antisense orientation. The transcriptional level of the ribosomal protein S6 was lower in c105 than in the wild-type plant. Introduction of the same fragment into the wild-type plant gave phenotypes similar to those of c105, so the phenotypes of c105 were due to the S6 antisense expression. The phenotypes suggest selectively reduced function of specific proteins rather than an overall decrease in protein function caused by defective ribosomal biogenesis.

Arabidopsis↗

PubMed2002

Increased levels of tissue endostatin in human malignant gliomas.

PURPOSE: Malignant gliomas are typically angiogenic and express greater amounts of angiogenic factors. We examined glioma tissues for their expression of an endogenous inhibitor of angiogenesis, endostatin, a COOH-terminal fragment of collagen XVIII. EXPERIMENTAL DESIGN: We examined frozen tissues from 51 patients with astrocytic tumors (grade 2, 13; grade 3, 9; and grade 4, 29). Frozen tissues were subjected to immunoblot analysis and immunohistochemistry for endostatin. Tumor vascular density was determined by calculating the percentage of tumor capillary vessel areas/tissue section area. Tissue concentrations of vascular endothelial growth factor and basic fibroblast growth factor were examined by enzyme immunoassay. RESULTS: The levels of endostatin protein estimated by immunoblotting were significantly higher in grade 4 than lower-grade glioma tissues. The immunoreactive bands for endostatin were identified as the fragment derived from noncollagenous domain 1 of collagen XVIII, a peptide 15 residues longer than endostatin toward the NH(2)-terminal end, by NH(2)-terminal amino acid sequencing. In addition to an intense immunoreactivity for endostatin in tumor blood vessels, sections from malignant gliomas showed widely distributed immunoreactivity around tumor cells near the hyperplastic microvessels. The tumor vascular density and the levels of vascular endothelial growth factor in grade 4 glioma tissues were significantly higher than grade 2 and grade 3 gliomas, whereas the levels of basic fibroblast growth factor were the same. CONCLUSIONS: The results indicate a positive correlation between the levels of tissue endostatin and malignancy grades in gliomas. The endostatin may be released near the tumor blood vessels with hyperplasia to counteract angiogenic stimuli in malignant gliomas.

Adult↗

PubMed2002

[A case of breast reconstruction with a rectus abdominis musculocutaneus flap following re-lumpectomy for local recurrence of breast cancer after breast conserving therapy].

A 42-year-old woman underwent breast conserving operation with irradiation for Stage I (T1 N0 M0) breast cancer at the 12 o'clock axis of her right breast. At six years after surgery, a solitary local recurrent tumor (1.2 cm in diameter) was found at the 2 o'clock axis of her right breast. No metastases were found at other sites. By the desire of the patient to conserve her breast, we performed re-lumpectomy with surgical margin (2 cm) and reconstructed with a rectus abdominis musculocutaneus flap to fill the large defect of breast tissue. One year and 5 months after surgery, the patient was doing well without recurrence, and was satisfied with the cosmetic effect.

Breast Neoplasms↗

PubMedDate not supplied

Continuous intravenous administration of a low dose of epoprostenol greatly decreased serum concentrations of endothelin-1 in primary pulmonary hypertension--a case report.

Endothelin-1 (ET-1) is known to be a principal factor in the pathogenesis of primary pulmonary hypertension (PPH). Recently intravenous administration of epoprosterol improved the survival rate in PPH. However, the effect of epoprosterol on ET-1 remains to be investigated. Therefore, we studied a patient with PPH who was treated with a low dose of epoprosterol and examined the serum concentration of ET-1 during the treatment. Epoprosterol greatly decreased the serum concentration of ET-1 in parallel with improvement of the clinical course, suggesting that ET-1 level may be a marker for treatment of PPH.

Adult↗