Biomedical subjects

Michiko Watanabe

Publications and source records attributed to Michiko Watanabe.

30 records · Page 2Linked to original sources

PubMed2003

Polyphenols from some foodstuffs as inhibitors of ovalbumin permeation through caco-2 cell monolayers.

Some spices showed high inhibitory activity against ovalbumin permeation through Caco-2 cell monolayers. Pimentol from allspice, rosmarinic acid and luteolin-7-O-beta-glucuronide from thyme, quercetin-3-O-beta-glucuronide from coriander and rutin from tarragon were identified as the active principles. A structure-activity relationship study among the active isolates and their related compounds indicated that the presence of a catechol structure played an important role in the inhibitory activity of each compound.

Anti-Allergic Agents↗

PubMed2003

Developmental transitions in cardiac conduction.

The proper sequence of electrical activation of the mature four-chambered heart requires specialized conduction pathways including the His-Purkinje system and a nearly complete separation of the atrial and ventricular myocardium. We tracked the emergence of the structure of the mature His-Purkinje system in the developing chicken embryo with anti-polysialylated neural cell adhesion molecule (PSA-NCAM) and the HNK1 antibody against a sulfated carbohydrate epitope. The function of the His-Purkinje system was assayed using extracellular electrodes and high-resolution voltage-sensitive two-dimensional optical mapping. The appearance of the mature form of the His-Purkinje system delineated by the markers coincided with the onset of the mature electrophysiological pattern of ventricular activation. These data suggest that, at the completion of ventricular septation, the His-Purkinje system undergoes critical structural and functional transitions that impact on the global pattern of conduction and contraction of the developing four-chambered heart.

Action Potentials↗

PubMed2002

The essential role of Cited2, a negative regulator for HIF-1alpha, in heart development and neurulation.

Cited2 is a cAMP-responsive element-binding protein (CBP)/p300 interacting transcriptional modulator and a proposed negative regulator for hypoxia-inducible factor (HIF)-1alpha through its competitive binding with HIF-1alpha to CBP/p300. Disruption of the gene encoding Cited2 is embryonic lethal because of defects in the development of heart and neural tube. Morphological and Doppler echocardiographic analyses of Cited2(-/-) embryos reveal severe cardiovascular abnormalities, including pulmonic arterial stenosis and ventricular septal defects accompanied by high peak outflow velocities, features of the human congenital cardiac defect termed tetralogy of Fallot. The mRNA levels of several HIF-1alpha-responsive genes, such as vascular endothelial growth factor (VEGF), Glut1, and phosphoglycerate kinase 1, increased in the Cited2(-/-) hearts. The increase of VEGF levels is significant, because defects in the Cited2(-/-) embryos closely resemble the major defects observed in the VEGF transgenic embryos. Finally, compared with wild-type, cultured fibroblasts from Cited2(-/-) embryos demonstrate an enhanced expression of HIF-1alpha-responsive genes under hypoxic conditions. These observations suggest that functional loss of Cited2 is responsible for defects in heart and neural tube development, in part because of the modulation of HIF-1 transcriptional activities in the absence of Cited2. These findings demonstrate that Cited2 is an indispensable regulatory gene during prenatal development.

Animals↗

PubMed2002

Initiation of apoptosis in the developing avian outflow tract myocardium.

Apoptosis occurs within the cardiac outflow tract (OFT) myocardium during normal development of chick hearts. This peak of apoptosis occurs at stage 30-31 and coincides with dramatic remodeling of the OFT, suggesting that apoptosis occurs to allow proper alignment of the great vessels over their respective ventricles. The signals that initiate apoptosis in this setting are unknown. The aim of this study was to characterize the cells undergoing apoptosis in the cardiac OFT myocardium and the cells that may influence this process. Two cell populations that may initiate apoptosis of the cardiomyocytes are the cardiac neural crest (CNC) cells and epicardial cells. We examined stage 30-31 chick embryos that had undergone removal of the CNC cells or had delayed epicardial growth for alterations of apoptosis. Removal of the CNC cells did not reduce the levels or pattern of apoptosis in the OFT myocardium. In contrast, impeding the growth of the epicardium over the OFT resulted in a 57% reduction in apoptotic cells in the OFT myocardium. Analysis of the apoptotic cells within the OFT myocardium showed that as many as 92% of them expressed cardiomyocyte markers. In the quail, the endothelial marker QH1 identified a component from the epicardium, endothelial cells, in regions where apoptosis is elevated in the OFT myocardium. These results suggest that a component from the epicardium, possibly endothelial cells, is required for the initiation of apoptosis in OFT cardiomyocytes.

Animals↗

PubMed2002

The pros and cons of apoptosis assays for use in the study of cells, tissues, and organs.

Programmed cell death or apoptosis occurs in many tissues during normal development and in the normal homeostasis of adult tissues. Apoptosis also plays a significant role in abnormal development and disease. Increased interest in apoptosis and cell death in general has resulted in the development of new techniques and the revival of old ones. Each assay has its advantages and disadvantages that can render it appropriate and useful for one application, but inappropriate or difficult to use in another. Understanding the strengths and limitations of the assays would allow investigators to select the best methods for their needs.

Animals↗

PubMed2002

An active compound against allergen absorption in hypoallergenic wheat flour produced by enzymatic modification.

Hypoallergenic wheat flour produced by modification with cellulase and actinase showed inhibitory activity against ovalbumin permeation in an in vitro model by using the Caco-2 cell monolayer. The activity was found in the cellulase preparation used for producing the flour. An active compound was isolated by HPLC and identified as Trp-Ser-Asn-Ser-Gly-Asn-Phe-Val-Gly-Gly-Lys by 1H-NMR data and Edman degradation. The undecapeptide, some oligopeptides with the N-terminal sequences and Trp ethyl ester showed activity at 10(-7) M, acetyl Trp being active at 10(-2) M. These data suggest that the Trp residue without a free carboxyl group would be required for the inhibitory activity of ovalbumin absorption through the intestinal tract.

Absorption↗

PubMed2002

[Direct assay for urine cortisol with cortisol kit [TFB]].

We examined Cortisol Kit [TFB] for direct assay of urine cortisol. And the multiplication by dilution factor of urine cortisol values in this kit was examined. The coefficient of correlation of cortisol levels (46 urine samples) between Cortisol Kit [TFB] and Chemilumi ACS-Cortisol II, which is another kit for direct assay of urine cortisol, was r = 0.858, y = 1.86x + 38.2 (p < 0.001). There were differences between the both cortisol levels of each urine sample in spite of the good coefficient of correlation. The urine cortisol values obtained from the standard curve in addition of 50 microliters of zero standard were 50-80% of the values obtained from the standard curve in the package insert. These results suggest that the specificity of the antibodies of both direct assay kits for urine cortisol may be different each other, and the multiplication by 1.09, the dilution factor due to the addition of zero standard to only urine sample, is unnecessary although it is indispensable for urine samples to add zero standard. Cortisol Kit [TFB] was very convenient for its easy assay procedure and short incubation.

Evaluation Studies as Topic↗

PubMedDate not supplied

Adenoviral transfer of antisenses or ribozyme to O6-methylguanine-DNA methyltransferase mRNA in brain-tumor model resistant to chloroethyl-nitrosourea.

Chloroethyl-nitrosourea is a potent chemotherapeutic agent for brain tumors. However, acquired resistance to this drug has become a serious problem for the treatment of patients. Previously, we established an animal model resistant to nitrosourea (Anticancer Res 19: 5313-5318, 1999). In this study, we evaluate the efficacies of antisense sequences and ribozyme transduction by an adenoviral vector utilizing this model. Adenoviral vectors encoding antisense sequences or ribozyme to MGMT mRNA were constructed, then MGMT-expressing glioma cells were infected with these viruses and 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea (ACNU) sensitivities were quantified. The adenoviral transfer of antisense RNA and ribozyme down-regulated the transcription and expression of MGMT in vitro. It also conferred sensitivity to nitrosourea in vitro and in vivo. However, the effect was minimal. These data suggest that incomplete depletion of MGMT is not sufficient to overcome the resistance and that additional optimization will be required for the complete reversion of drug resistance.

Adenoviridae↗

PubMedDate not supplied

Mutant ICR mouse, kuru2, manifests hearing impairment and abnormal behavior.

BACKGROUND: Establishment of mutant animals presents valuable information on corresponding human diseases. We established a mutant mouse, kuru2, from the previously reported Ascites ICR Mouse. MATERIALS AND METHODS: Epileptic individuals of Ascites ICR Mouse were mated and maintained with sibling mating. This mouse was characterized by hearing impairment and abnormal behavior such as ataxic gait, disturbance of positional sense, hyperirritability, head-tossing and circling movement. RESULTS: No detectable auditory brain stem response was evoked from an early stage of life. Abnormal behavior started from 4 to 12 weeks of age. Microscopic examination revealed no major abnormalities in the central nervous system. In the inner ear, the vestibule and cochlea were well developed, however degeneration of the spiral ganglions was observed at a late age. The genetic mode was autosomal recessive. DISCUSSION: Since this mouse has a distinctive phenotype, the animal may provide an understanding of hereditary hearing impairment and abnormal behavior.

Animals↗

PubMedDate not supplied

Progressive degeneration of stereocilia in cochlear hair cells in hearing-impaired kuru2 mice.

BACKGROUND: We previously isolated a mouse strain, kuru2, which exhibits abnormal behavior and hearing impairment. To investigate the etiology of this impairment, the ultrastructure of the inner ear was examined. MATERIALS AND METHODS: The morphologies of the cochlea and the vestibule of control (Jcl:ICR) and mutant mice were analyzed by electron microscopy. In some experiments, the mice were cross-mated and their offspring examined. RESULTS: The mutant mice displayed progressive degeneration of the stereocilia in the cochlea. The stereocilia started to degenerate on post-natal day 10 and, subsequently, the hair bundles continued to degenerate. On day 18, degeneration of the stereocilia was complete. In contrast, the vestibule was intact. DISCUSSION: Many mutant mice display hearing impairment These mice demonstrate a characteristic morphology of the inner ear and, since correlations may be made with corresponding human diseases, the current results could contribute to the further understanding of hearing impairment mechanisms.

Animals↗

PubMedDate not supplied

Local delivery of doxorubicin for malignant glioma by a biodegradable PLGA polymer sheet.

Implantable, biocompatible and biodegradable devices bearing an anticancer drug can provide promising local therapy to patients with malignant disorders. With the aim of treating brain tumors, especially gliomas, a membranous sheet containing doxorubicin was produced by co-polymerization to poly(D,L-lactide-co-glycolide) (PLGA). When release of the drug from the sheet was measured, sustained release continued until day 34. The data contrasted with the burst release from material containing a higher proportion of the drug. In terms of biodegradability, a subcutaneous 3 x 3-mm tetragonal sheet was almost completely absorbed by day 80. When a glioma was implanted subcutaneously and the tumor nodule exposed to the sheet, the device inhibited tumor growth significantly. The sheet consisted of an amorphous structure with cavities estimated to have a diameter of 0.5 - 3 microm by electron microscopic observation. Since the sheet is implantable, biodegradable and has a sustained-drug release property, the device may play a role in the local therapy of brain tumors.

Animals↗

PubMedDate not supplied

Inhibition of poly (ADP-ribose) polymerase as a protective effect of nicaraven in ionizing radiation- and ara-C-induced cell death.

BACKGROUND: Nicaraven is a drug used for patients with a subarachnoid hemorrhage. It crosses the blood-brain barrier and has potent antivasospastic and brain-protective effects. While nicaraven scavenges the hydroxyl radical, the mechanism of its protection remains obscure. In addition to the hydroxyl radical scavenging effect, nicaraven also exhibits inhibitory action on poly (ADP-ribose) polymerase (PARP). The mechanism of the pharmacological action of nicaraven has not yet been clarified. MATERIALS AND METHODS: Human myeloid HL-525 cells were exposed to ionizing radiation or hydrogen peroxide and the effect of nicaraven on the activation of the Egr-1 promoter was measured. Next, the action of the drug on DNA fragmentation and inhibition of thymidine uptake caused by the genotoxic stimulation of ionizing radiation or cytosine B-D-arabinofuranoside (ara-C) were assessed. Finally, direct inhibition of the PARP enzyme by nicaraven was measured. RESULTS: Nicaraven did not inhibit the activation of the Egr-1 promoter caused by H2O2 and the activation caused by ionizing radiation. However, the drug repressed DNA fragmentation and increased thymidine uptake dose-dependently. Nicaraven had a direct inhibitory effect on PARP. DISCUSSION: The effect of nicaraven on the Egr-1 promoter was different from that of another free-radical scavenger, N-acetyl cysteine. Nicaraven demonstrated similar protection of the PARP inhibitors including 3-aminobenzamide. Since nicaraven directly inhibits the PARP enzyme, the drug might be useful in oncology as well as in studying tissue-damaging conditions characterized by increased PARP activity.

Acetylcysteine↗