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Biomedical subjects

K Ueda

Publications and source records attributed to K Ueda.

At least 73 records · Page 4Linked to original sources
PubMed2001

HeLa ZIP kinase induces diphosphorylation of myosin II regulatory light chain and reorganization of actin filaments in nonmuscle cells.

Dlk/ZIP kinase is a serine/threonine kinase highly homologous to DAP kinase. We have reported that HeLa ZIP kinase (hZIPK) phosphorylated the regulatory light chain of myosin II (MRLC) at both Ser19 and Thr18 in vitro. In this study, we demonstrate that hZIPK also induces the diphosphorylation of MRLC in nonmuscle cells. Peptide mapping revealed that transient transfection of hZIPK into HeLa cells caused diphosphorylation of MRLC. In contrast, transfection of the kinase inactive mutant of hZIPK did not induce any phosphorylation of MRLC. Using antibodies specific for mono- or diphosphorylated MRLC, we showed that diphosphorylated MRLC induced by the overexpression of hZIPK was concentrated in striking aggregates or bundles of actin filaments in HeLa cells, while monophosphorylated MRLC showed no prominent localization to these aggregates. Overexpression of hZIPK also induced dramatic changes in cell shape and disruption of nuclear morphology reminiscent of changes during apoptosis. These effects of hZIPK were suppressed by the coexpression of a mutant MRLC where both phosphorylation sites were replaced with alanine, indicating that the changes in actin organization were a consequence of MRLC diphosphorylation. These results suggested that hZIPK plays a role in regulating actin organization and cell morphology in non-muscles and at least part of its effects are mediated through the diphosphorylation of MRLC.

Actin Cytoskeleton↗
PubMed2001

Accumulation of iodized oil within the nonneoplastic liver adjacent to hepatocellular carcinoma via the drainage routes of the tumor after transcatheter arterial embolization.

PURPOSE: After transcatheter arterial embolization (TAE) with iodized oil (Lipiodol), a relatively dense accumulation of Lipiodol is often seen in the nontumorous liver adjacent to a hypervascular hepatocellular carcinoma (HCC) nodule. We compared this phenomenon with the findings obtained with single-level dynamic CT during hepatic arteriography (SLDCTHA) and presumed its possible mechanism. METHODS: Fifty-six patients with HCC underwent hepatic angiography including SLDCTHA followed by segmental or subsegmental TAE with a mixture of an anticancer drug and Lipiodol. We compared the drainage area of the HCC depicted on SLDCTHA with the Lipiodol accumulation in the nontumorous liver adjacent to the HCC on CT after TAE (LpCT). RESULTS: In 26 of the 56 patients, a definite corona enhancement around the HCC, suggesting the drainage of blood from the tumor into the surrounding liver parenchyma, was seen on the late phase of SLDCTHA. In 17 of these 26 patients (65.4%), LpCT showed a more intense accumulation of Lipiodol in the nontumorous liver adjacent to the HCC that corresponded to the drainage area revealed on SLDCTHA. CONCLUSION: The drainage of blood from the HCC was considered to be a possible mechanism of the accumulation of Lipiodol in the nontumorous liver adjacent to the HCC.

Carcinoma, Hepatocellular↗
PubMed2001

Deterioration of axotomy-induced neurodegeneration by group IIA secretory phospholipase A2.

Phospholipase A2 (PLA2) is proposed to play a role in the repair of the ruptured membrane after axotomy. In neonatal rats, we examined the effect of Group IIA secretory PLA2 (sPLA2-IIA) on axotomy-induced cell death of motoneurons. sPLA2-IIA significantly induced death of axotomized motoneurons. Indoxam, a specific inhibitor for sPLA2-IIA, protected motoneurons from the sPLA2-IIA-induced deterioration. The present study indicated that sPLA2-IIA possessed neurotoxic effect rather than neuroprotective effect against facial nerve.

Animals↗
PubMed2001

Synthesis of a tetronic acid library focused on inhibitors of tyrosine and dual-specificity protein phosphatases and its evaluation regarding VHR and cdc25B inhibition.

Selective inhibitors of protein tyrosine phosphatases (PTPs) and dual-specificity phosphatases (DSPs) are expected to be useful tools for clarifying the biological functions of the PTPs themselves and also to be candidates for novel therapeutics. We planned a library approach for the identification of PTP/DSP inhibitors in which 3-acyltetronic acid is used as a "core" phosphate mimic. A series of novel tetronic acid derivatives were synthesized and evaluated as inhibitors of the dual-specificity protein phosphatases VHR and cdc25B. Several compounds are found to be potent inhibitors of cdc25B, which is a key enzyme for cell-cycle progression. The promising results described herein strongly indicated that this tetronic acid library is potent as a library focused on the PTP/DSP-selective inhibitor.

Cell Cycle Proteins↗
PubMed2001

Analysis of 825C/T polymorphism of G proteinbeta3 subunit in obese/diabetic Japanese.

The GNB3 825C/T polymorphism, which is common worldwide, is associated with enhanced G-protein activation. The frequency of 825-T allele was increased with body mass index (BMI) and finally had a high frequency in relatively mild obese (BMI >27 kg/m(2)) subjects in some populations. In the present study, we investigated 208 severely obese [BMI >or=30 kg/m(2) (97th percentile)] Japanese subjects including 146 probands with diabetes. No increase in the 825-T allele frequency was observed in the 208 severely obese and even in a subgroup of the 55 most obese [BMI >or=35 kg/m(2) (99.7th percentile)] subjects compared with that in 150 controls (BMI <25 kg/m(2)) (0.48 and 0.48 vs 0.51, respectively). Also, the frequency was not increased in the 146 obese subjects with diabetes (0.48). We concluded that the 825-T allele is not associated with obesity or diabetes associated with obesity at least in the Japanese population.

Body Mass Index↗
PubMed2001

Carcinoembryonic antigen-specific suicide gene therapy of cytosine deaminase/5-fluorocytosine enhanced by the cre/loxP system in the orthotopic gastric carcinoma model.

Tumor-specific gene delivery is crucial to achieving successful effects in suicide gene therapy. Carcinoembryonic antigen (CEA) promoter has been widely used for this purpose, but the expression level of tumor-specific promoters such as CEA promoter is generally low. In the previous study, we used the Cre/loxP system and showed that LacZ expression by the CEA promoter was remarkably enhanced and maintained its specificity using the Cre/loxP regulation system. In this study, the Cre/loxP system was first applied to augmentation of selective expression of the cytosine deaminase (CD) gene as a suicide gene therapy in CEA-producing cells. The double infection with AxCEANCre expressing Cre recombinase under the control of the CEA promoter and AxCALNLCD expressing the CD gene under the control of the CAG promoter by the Cre switching system rendered CEA-producing tumor cells 13-fold more sensitive to 5-fluorocytosine (5-FC) compared with the single infection with AxCEACD expressing CD gene driven by the CEA promoter. The therapeutic efficacy of the enhanced CD/5-FC suicide gene therapy was evaluated in orthotopic implantation models of human gastric carcinoma. Adenovirus vectors (1 x 10(9) plaque-forming units) were administered i.p. into mice three times, and then 5-FC was administered i.p. for the next 10 days. Tumor volume and weight in mice treated with AxCEANCre and AxCALNLCD/5-FC were significantly reduced as compared with those in mice treated not only with Mock (AxCALacZ) but also with AxCEACD/5-FC (P < 0.0001). This beneficial effect on tumor burden was also reflected in the overall survival. The survival periods of the mice treated with AxCEANCre and AxCALNLCD/5-FC were longer than those of mice treated with Mock or AxCEACD/5-FC (P < 0.01). These results suggested that application of the Cre/loxP system could provide a new approach for enhanced selective suicide gene therapy of CD/5-FC for the treatment of advanced gastric carcinoma.

Adenoviridae↗
PubMed2001

Development and maturation of taste buds of the palatal epithelium of the rat: histological and immunohistochemical study.

Palatal taste buds are intriguing partners in the mediation of taste behavior and their spatial distribution is functionally important for suckling behavior, especially in the neonatal life. Their prenatal development has not been previously elucidated in the rat, and the onset of their maturation remains rather controversial. We delineated the development and frequency distribution of the taste buds as well as the immunohistochemical expression of alpha-gustducin, a G protein closely related to the transduction of taste stimuli, in the nasoincisor papilla (NIP) and soft palate (SP) from the embryonic day 17 (E17) till the postnatal day 70 (PN70). The main findings in the present study were the development of a substantial number of taste pores in the SP of fetal rats (60.3 +/- 1.7 out of 122.8 +/- 5.5; mean +/- SD/animal at E19) and NIP of neonatal rats (9.8 +/- 1.0 out of 44.8 +/- 2.2 at PN4). alpha-gustducin-like immunoreactivity (-LI) was not expressed in the pored taste buds of either prenatal or newborn rats. The earliest expression of alpha-gustducin-LI was demonstrated at PN1 in the SP (1.5 +/- 0.5 cells/taste bud; mean +/- SD) and at PN4 in the NIP (1.4 +/- 0.5). By age the total counts of pored taste buds continuously increased and their morphological features became quite discernible. They became pear in shape, characterized by distinct pores, long subporal space, and longitudinally oriented cells. Around the second week, a remarkable transient decrease in the total number of taste buds was recorded in the oral epithelium of NIP and SP, which might be correlated with the changes of ingestive behaviors. The total counts of cells showing alpha-gustducin-LI per taste bud gradually increased till the end of our investigation (14.1 +/- 2.7 in NIP and 12.4 +/- 2.5 in SP at PN70). We conclude that substantial development of taste buds began prenatally in the SP, whereas most developed entirely postnatal in the NIP. The present study provides evidence that the existence of a taste pore which is considered an important criterion for the morphological maturation of taste buds is not enough for the onset of the taste transduction, which necessitates also mature taste cells. Moreover, the earlier maturation of palatal taste buds compared with the contiguous populations in the oral cavity evokes an evidence of their significant role in the transmission of gustatory information, especially in the early life of rat.

Animals↗
PubMed2001

Reversal of drug resistance mediated by multidrug resistance protein (MRP) 1 by dual effects of agosterol A on MRP1 function.

We previously isolated agosterol A (AG-A) from a marine Spongia sp. and found that it completely reversed colchicine resistance in P-glycoprotein (Pgp)-over-expressing KB-C2 cells and vincristine resistance in multidrug-resistance protein (MRP)1-over-expressing CV60 cells. However, a tri-deacetylated derivative of AG-A (IAG-A) showed almost no activity in reversing Pgp- or MRP1-mediated drug resistance. In this study, we examined the mechanisms by which AG-A reverses MRP1-mediated drug resistance by investigating the interaction between agosterols and MRP1 in MRP1-over-expressing human KB carcinoma (KB/MRP) cells. [3H]-Leukotriene C4 (LTC4), [3H]-2,4-dinitrophenyl-S-glutathione uptake into membrane vesicles prepared from KB/MRP cells and intracellular [3H]-vincristine accumulation and efflux in KB/MRP cells were measured with or without AG-A and/or inactive IAG-A. AG-A reduced MRP1-mediated [3H]-LTC4 transport in a dose-dependent manner, but IAG-A did not. Inhibition by AG-A was competitive, with a K(i) value of 31 microM. AG-A at 10 microM enhanced the accumulation of [3H]-vincristine in KB/MRP cells to the level of that in control cells in the absence of the agent. Likewise, ATP-dependent efflux of [3H]-vincristine from KB/MRP cells was enhanced compared with KB-3-1 cells and inhibited by AG-A. In addition, AG-A reduced intracellular levels of glutathione, a compound required for MRP1-mediated transport of some anti-cancer drugs. These findings suggest that AG-A reverses MRP1-mediated drug resistance by directly inhibiting the capacity of MRP1 to transport drugs. In addition, the capacity of AG-A to reduce cellular glutathione levels may contribute to the modulating activity of MRP1.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2001

Effects of posture on cardiac autonomic nervous activity in patients with congestive heart failure.

OBJECTIVES: We aimed to clarify which recumbent position is preferred by patients with congestive heart failure (CHF) and to evaluate whether cardiac autonomic nervous activity is different among three recumbent positions (supine, left lateral decubitus, right lateral decubitus) in patients with CHF. BACKGROUND: It remains unclear whether cardiac autonomic nervous activity is different among three recumbent positions in patients with CHF. METHODS: We studied 17 male CHF patients (66+/-7 years) and 17 age- and gender-matched healthy subjects (66+/-7 years). Each subject underwent 24-h ambulatory electrocardiographic monitoring. A channel was used to record the CM5 lead, and another to record the signal of the patient's posture with use of a newly developed small-sized detector (3.2 cm x 3.2 cm). By using spectral analysis of heart rate variability, frequency-domain measures were calculated and compared among the three recumbent positions. Normalized high-frequency (HF: 0.15 to 0.40 Hz) power was used as an index of vagal activity and the low frequency (0.04 to 0.15 Hz)/HF power ratio was used as an index of sympathovagal balance. RESULTS: In patients with CHF, the time for the right lateral decubitus position was two-fold longer than that for the supine and left lateral decubitus positions. The increased cardiac sympathetic activity and decreased vagal tone in CHF patients were normalized in the right lateral decubitus position. CONCLUSIONS: The right lateral decubitus position in patients with CHF may be a self-protecting mechanism of attenuating the imbalance of cardiac autonomic nervous activity.

Aged↗
PubMed2001

Human ABCA1 contains a large amino-terminal extracellular domain homologous to an epitope of Sjögren's Syndrome.

ABCA1 has been suggested to play a key role in cellular lipid release from peripheral cells. In order to study structure-function relationship of this protein, the protein product of a full-length human ABCA1 cDNA was examined for its functions and topological orientation. The electrophoretic mobilities of human ABCA1 expressed in transfected cells increased when treated with N-glycosidase F, suggesting that ABCA1 is highly glycosylated. The ABCA1 was photoaffinity-labeled with ATP and mediated the apoA-I-dependent-release of cholesterol and phospholipid. The influenza hemagglutinin (HA) epitope was introduced into the amino-terminus (N-HA) or between the residues 207 and 208 (207-HA) of the protein. While an antibody against the C-terminus peptide of ABCA1 detected both fusion proteins, an anti-HA antibody did not react with the N-HA fusion protein. Confocal microscopy demonstrated strong cell surface signal with the anti-HA antibody of nonpermeabilized HEK293 cells expressing the 207-HA fusion protein. The results suggested that the signal peptide in the amino-terminal region is cleaved off in its mature form and that the following large hydrophilic region is exposed to outside of cells unlike previously proposed models. We found that this amino-terminal extracellular domain contains a segment homologous to the autoantigen SS-N, an epitope of Sjögren's syndrome, and further identified that ABCA7 codes for the autoantigen SS-N.

ATP Binding Cassette Transporter 1↗
PubMed2001

Stable operation of a 300-m laser interferometer with sufficient sensitivity to detect gravitational-wave events within our galaxy.

TAMA300, an interferometric gravitational-wave detector with 300-m baseline length, has been developed and operated with sufficient sensitivity to detect gravitational-wave events within our galaxy and sufficient stability for observations; the interferometer was operated for over 10 hours stably and continuously. With a strain-equivalent noise level of h approximately 5x10(-21)/sqrt[Hz], a signal-to-noise ratio of 30 is expected for gravitational waves generated by a coalescence of 1.4M-1.4M binary neutron stars at 10 kpc distance. We evaluated the stability of the detector sensitivity with a 2-week data-taking run, collecting 160 hours of data to be analyzed in the search for gravitational waves.

Astronomy↗
PubMed2001

Enantioselective total synthesis of a potent antitumor antibiotic, fredericamycin A.

The asymmetric total synthesis of both enantiomers of the potent antitumor antibiotic fredericamycin A (1) is detailed based on the protocol for the construction of its peri-hydroxy polyaromatic skeleton bearing the chirality at the spiro carbon via a strong base-induced cycloaddition of suitably substituted homophthalic anhydrides (AB-ring unit) with an optically active CDEF-ring unit. Particular attention has been given to the novel synthesis of the optically active spiro carbon center by a stereospecific rearrangement of optically active benzofuzed-trans-epoxy acylates leading to spirocyclopentane-1,1'-indane systems. This method is quite useful for the construction of an optically active spiro compound and was applied to the synthesis of the optically pure CDEF-ring unit of 1. Cycloaddition of the optically pure CDEF-ring unit to AB-ring units prepared via benzyne afforded two natural and unnatural-type hexacyclic compounds, which were converted to natural and unnatural enantiomers of synthetic 1, and the absolute configuration of natural 1 was determined as S.

Antibiotics, Antineoplastic↗
PubMed2001

Initial and long-term results of directional coronary atherectomy in unprotected left main coronary artery.

Angioplasty in the unprotected left main coronary artery (LMCA) has been controversial. Recently, several studies have suggested that new procedures and devices such as directional coronary atherectomy (DCA) and stents may change this situation. Although there are many reports of unprotected LMCA stenting, there are few reports of DCA of this lesion. Therefore, initial and long-term results were evaluated in 101 patients who underwent DCA for unprotected LMCA in our hospital. Emergency procedures were performed in 15 patients and electively in 86 patients. Scheduled angiographic follow-up was routinely performed, and all patients were clinically followed for >4 months after DCA. Technical success was achieved in 99%, and in-hospital outcomes were cardiac death (2%), noncardiac death (4%), Q-wave myocardial infarction (1%), non-Q-wave myocardial infarction (8.9%), coronary artery bypass grafting (0%), and repeat angioplasty (4%). In-hospital results varied considerably, depending on presentation. In-hospital mortality was significantly higher in the emergency, left ventricular ejection fraction < or =35%, and high-risk surgical subgroups. The angiographic restenosis rate was 20.4% at follow-up, and its predictor was postminimal lumen diameter by multivariate analysis. Mean clinical follow-up was 2.8 years; estimated 1- and 3-year survival rates were 87% and 80.7%, respectively. The cardiac survival rate of the low-risk surgical subgroup was significantly higher than that of the high-risk surgical subgroup (p <0.05). Thus, our data show that DCA can be performed safely and effectively in unprotected LMCA with an acceptable low restenosis rate and high survival rate.

Adult↗
PubMed2001

Activation of latent Kaposi's sarcoma-associated herpesvirus by demethylation of the promoter of the lytic transactivator.

Kaposi's sarcoma-associated herpesvirus (KSHV) is strongly linked to Kaposi's sarcoma, primary effusion lymphomas, and a subset of multicentric Castleman's disease. The mechanism by which this virus establishes latency and reactivation is unknown. KSHV Lyta (lytic transactivator, also named KSHV/Rta), mainly encoded by the ORF 50 gene, is a lytic switch gene for viral reactivation from latency, inasmuch as it is both essential and sufficient to drive the entire viral lytic cycle. Here we show that the Lyta promoter region was heavily methylated in latently infected cells. Treatment of primary effusion lymphoma-delivered cell lines with tetradecanoylphorbol acetate caused demethylation of the Lyta promoter and induced KSHV lytic phase in vitro. Methylation cassette assay shows demethylation of the Lyta promoter region was essential for the expression of Lyta. In vivo, biopsy samples obtained from patients with KSHV-related diseases show the most demethylation in the Lyta promoter region, whereas samples from a latently infected KSHV carrier remained in a methylated status. These results suggest a relationship among a demethylation status in the Lyta promoter, the reactivation of KSHV, and the development of KSHV-associated diseases.

DNA Methylation↗
PubMed2001

Influence of alkyl substitution on the gas-phase stability of 1-adamantyl cation and on the solvent effects in the solvolysis of 1-bromoadamantane.

1-Adamantyl cations having three methyl groups or one, two, or three isopropyl groups on the 3-, 5-, and 7-positions were found by FT ICR to be more stable than the 1-adamantyl cation and that the stability increases with the number of isopropyl group. The relative stabilities calculated by PM3 were in good agreement with the experimental results. In contrast, the sequence of the rates for the solvolysis in nonaqueous solvents are 3,5,7-(Me)(3)-1-AdBr < 1-bromoadamantane (1-AdBr) < 3,5,7-(n-Pr)(3)-1-AdBr < 3,5,7-(i-Pr)(3)-1-AdBr. The rates of solvolysis of 3,5,7-(i-Pr)(3)-1-AdBr and 3,5,7-(n-Pr)(3)-1-AdBr relative to 1-AdBr at 25 degrees C are 15 and 3.8 in EtOH, respectively, but markedly decreases with the increase in the amount of added water, reaching 0.84 and 0.15, respectively, in 60% EtOH. Reflecting these effects of water, the Grunwald-Winstein (GW) relationship for 3,5,7-(i-Pr)(3)-1-AdBr and 3,5,7-(n-Pr)(3)-1-AdBr against Y(Br) is linear for nonaqueous alcohols (EtOH, MeOH, TFE-EtOH, TFE, 97% HFIP), but marked downward deviations are observed for aqueous organic solvents, in particular, aqueous ethanol and aqueous acetone. The effect of the alkyl substituents to diminish relative solvolytic reactivity in EtOH-H(2)O mixtures may be ascribed to a blend of steric hindrance to Betarphinsted base-type hydration to the beta-hydrogens and hydrophobic interaction of the alkyl groups with ethanol to make the primary solvation shell less ionizing. The introduction of one nonyl group to the 3-position showed much smaller deviations in the GW relationship than the case of 3,5,7-(n-Pr)(3)-1-AdBr. The markedly decelerated solvolysis of alkylated 1-bromoadamantanes in aqueous organic solvents is a kinetic version of anomalously diminished dissociation of alkylbenzoic acids in aqueous ethanol and aqueous tert-butyl alcohol that was demonstrated by Wepster and co-workers a decade ago and ascribed to hydrophobic effects.

Journal Article↗
PubMed2001

New method of the chemical state imaging by EPMA-EXEFS.

A novel two dimensional imaging technique of the chemical bonding state was developed by combining the extended X-ray emission fine structure method with an electron probe X-ray microanalyzer mapping technology. With this method, chemical state images of some aluminum standard samples were obtained. It was confirmed that the obtained images provide correct information of chemical states.

Journal Article↗