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Y Kudo

Publications and source records attributed to Y Kudo.

At least 145 records · Page 8Linked to original sources
PubMed1997

The phylogeny of the genera Chryseomonas, Flavimonas, and Pseudomonas supports synonymy of these three genera.

The 16S rRNA sequences of Chryseomonas luteola, the type species of the genus Chryseomonas, and Flavimonas oryzihabitans, the type species of the genus Flavimonas, were determined. These sequences were compared with the sequences of 27 representative strains of the genus Pseudomonas. C. luteola and F. oryzihabitans were located in the cluster that contains Pseudomonas aeruginosa, the type species of genus Pseudomonas Migula 1894, and the levels of 16S rRNA sequence homology between P. aeruginosa and the other two species were more than 93.9%. All of the strains of the genus Pseudomonas sensu stricto whose sequences have been determined were included in the P. aeruginosa cluster. These results suggested that Chryseomonas, Flavimonas, and Pseudomonas are synonymous, and we concluded that Chryseomonas and Flavimonas are junior subjective synonyms of Pseudomonas.

Base Sequence↗
PubMed1997

Overexpression of cyclin-dependent kinase-activating CDC25B phosphatase in human gastric carcinomas.

CDC25 phosphatases activate cyclin-dependent kinases by removing inhibitory phosphate groups on the molecules and positively regulate the cell cycle progression. The expression of CDC25A, B and C was examined in gastric carcinoma cell lines and gastric carcinoma tissues by northern blotting and immunohistochemistry. The gastric carcinoma cell lines expressed CDC25A, B and C mRNA at various levels. The expression levels of CDC25B were generally higher than those of CDC25A and C. Of the 40 gastric carcinomas, 70% of the tumors expressed CDC25B mRNA at higher levels than the corresponding normal mucosas, while 38% overexpressed CDC25A mRNA. The CDC25C expression was at very low or undetectable levels. No obvious correlation was detected between the expression of CDC25B and p53 gene mutations. Immunohistochemically, CDC25-positive tumor cells were detected in 43 (78%) of 55 gastric carcinoma cases, of which 27 (49%) were strongly positive. Strong expression of CDC25B protein was associated with advanced stage and deep invasion. Furthermore, the incidence of strong expression was significantly higher in carcinomas with nodal metastasis than in those without metastasis. These findings suggest that overexpression of CDC25B may favor development and progression and may be an indicator of malignant behavior of gastric carcinomas.

Adenocarcinoma↗
PubMed1997

Reduced expression of cyclin-dependent kinase inhibitor p27Kip1 is associated with advanced stage and invasiveness of gastric carcinomas.

Reduced expression of a cyclin-dependent kinase inhibitor p27Kip1 has recently been shown to predict poor survival of patients with breast and colorectal cancers. We studied the expression of p27Kip1 in gastric carcinomas by northern blotting, western blotting and immunohistochemistry to determine whether lack of p27 has implications for aggressiveness of gastric cancer. Reduced expression of p27 was detected in 40% of the gastric carcinomas at the mRNA level, while it was detected in 57% at the protein level. No gross alterations of the p27 gene were observed in any of the cases examined by Southern blot analysis. Immunohistochemical studies revealed that the expression of p27 was well preserved in most of the gastric adenomas, whereas it was so in only 26% of the gastric carcinomas. Fifty-six percent of the carcinomas showed almost no p27-positive cells. Decrease of p27-positive cells significantly correlated with advanced stage, depth of tumor invasion and lymph node metastasis. The expression of p27 showed an inverse correlation with the expression of cyclin E. These findings suggest that reduction of p27Kip1 protein may reflect the progression of gastric carcinomas and may be an indicator of high-grade malignancy.

Adenocarcinoma↗
PubMed1997

Expression of p21WAF1/CIP1 in colorectal adenomas and adenocarcinomas and its correlation with p53 protein expression.

The expression of p53-inducible cyclin-dependent kinase inhibitor, p21WAF1/CIP1 in non-neoplastic mucosa, adenoma and adenocarcinoma of the colorectum was examined by immunohistochemistry and western blotting and its relation with the expression of p53 protein was analyzed. Non-neoplastic epithelial cells at the surface area showing no proliferative activity expressed p21WAF1/CIP1. The expression of p21WAF1/CIP1 was immunohistochemically detected in 55% (206/377) of the adenomas and 66% (190/289) of the adenocarcinomas, respectively. The incidence of strongly positive cases was significantly higher in the adenocarcinomas (27%) than in the adenomas (18%) (P < 0.05). The incidence of cases with strong p21WAF1/CIP1 expression was higher in stages 0, 1 and 2 carcinomas than in stages 3 and 4 carcinomas (P < 0.05). A decrease in the incidence of cases with strong expression was detected in carcinomas invading deeper than muscularis propria. The incidence of strongly positive cases was significantly lower in carcinomas with lymph node metastasis than those without metastasis (P < 0.05). The expression of p21 as well as p53 detected by western blotting was compatible with the results of immunohistochemistry in most cases examined. However, there was no significant correlation between the expression of p21WAF1/CIP1 and the abnormal accumulation of p53. These findings overall suggest that: (i) the physiological expression of p21WAF1/CIP1 may be associated with cellular senescence of colorectal mucosa; (ii) reduced expression of p21WAF1/CIP1 may participate in the progression of colorectal carcinoma; and (iii) p53-independent pathway may be considerably involved in the induction of p21WAF1/CIP1.

Adenocarcinoma↗
PubMed1997

Perineural and neural involvement in skin cancers.

BACKGROUND: Malignant skin tumors rarely spread along nerves. Complete resection of involved nerves is often unsuccessful. OBJECTIVE: In the treatment of tumors with perineural invasion, surgeons should accurately estimate the extent of distant spread. METHODS: We report six cases of skin cancers, including two basal cell carcinomas, two squamous cell carcinomas, and two neurotropic malignant melanomas, that invaded nerve or perineural spaces. RESULTS: In three of the cases, the tumors developed on the face and involved the infraorbital nerves or its branches. Two patients suffered from tumors on old burn scars of lower legs. Branches of posttibal nerves were involved in both cases. In the last case, tumor invasion of a branch of the greater occipital nerve was detected. CONCLUSION: The extent of surgical excision should include the area of skin supplied by the affected nerve, which must be resected in continuity.

Adult↗
PubMed1997

Mechanisms underlying the rapid depolarization produced by deprivation of oxygen and glucose in rat hippocampal CA1 neurons in vitro.

Intracellular recordings were made to investigate the mechanism, site, and ionic basis of generation of the rapid depolarization induced by superfusion with ischemia-simulating medium in hippocampal CA1 pyramidal neurons of rat tissue slices. Superfusion with ischemia-simulating medium produced a rapid depolarization after approximately 6 min of exposure. When oxygen and glucose were reintroduced, the membrane potential did not repolarize but depolarized further, reaching 0 mV approximately 5 min after reintroduction. Simultaneous recordings of changes in cytoplasmic Ca2+ concentration ([Ca2+]i) and membrane potential recorded from 1-[6-amino-2-(5-carboxy-2-oxazolyl)-5-benzofuranyloxy]-2-(2- amino-5-methylphenoxy)-ethane-N,N,N',N'-tetraacetic acid pentaacetoxymethyl ester (Fura-2/AM) loaded slices revealed a rapid increase in [Ca2+]i in all CA1 layers corresponding to the rapid depolarization of the soma membrane. The result suggests that the rapid depolarization is generated not only in the soma but also in the apical and basal dendrites. Application of 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), DL-2-amino-4-phosphonobutyric acid, and DL-2-amino-3-phosphonopropionic acid or bicuculline did not affect the amplitude and the maximal slope. Reduction in the concentration of extracellular Ca2+ or addition of CNQX or DL-2-amino-5-phosphonopentanoic acid delayed the onset of the rapid depolarization. The amplitude of the rapid depolarization recorded with Cs acetate electrodes in tetraethylammonium-containing medium had a linear relationship to the membrane potential between -50 and 20 mV. The reversal potential was shifted in the hyperpolarizing direction by a decrease in either [Na+]o or [Ca2+]o, whereas the reversal potential was shifted in the depolarizing direction by a decrease in [Cl-]o or using CsCl electrodes. An increase or decrease in [K+]o did not affect the reversal potential. These results indicate that the rapid depolarization is Na+, Ca2+, and Cl- dependent. The lack of effects of changes in [K+]o is probably due to the accumulation of interstitial K+ before generating the rapid depolarization. Prolonged application of ouabain (30 microM) caused an initial small hyperpolarization, a subsequent slow depolarization, and a rapid depolarization. In summary, the present study has demonstrated that the rapid depolarization is voltage-independent and is probably due to a nonselective increase in permeability to all participating ions, which may occur only in pathological conditions. The underlying conductance change is primarily the result of inhibition of Na,K-ATPase activity in the recorded neuron.

Animals↗
PubMed1997

Factors that reverse the persistent depolarization produced by deprivation of oxygen and glucose in rat hippocampal CA1 neurons in vitro.

In CA1 pyramidal neurons in rat hippocampal tissue slices, superfusion with ischemia-simulating medium produced a rapid depolarization after 6 min of exposure. The membrane potential eventually reached 0 after 5 min (a persistent depolarization), even when oxygen and glucose were reintroduced. The role of various ions in the reversal of this persistent depolarization after reintroduction of oxygen and glucose was investigated. The peak of the persistent depolarization was decreased in solutions containing reduced Na+ or Ca2+ and in solutions containing Co2+ or Ni2+. In contrast, the depolarization was not affected by reduction of external K+ or Cl- or by addition of tetrodotoxin (TTX), flunarizine, or nifedipine. These results suggest that sustained Na+ and Ca2+ influxes produce the persistent depolarization. The membrane potential recovered after reintroduction of oxygen and glucose in low Ca2+, low Cl-, or K+-rich medium and in TTX- or tetraethylammonium-containing medium, but not in low Na+ or low K+ medium and in flunarizine- or nifedipine-containing medium. Either reduction in extracellular Ca2+ or addition of Co2+ was the most effective in promoting recovery from the persistent depolarization, suggesting that Ca2+ influx has a key role in causing the membrane dysfunction. The peak of the persistent depolarization was reduced by 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), DL-2-amino-5-phosphonopentanoic acid (AP5), DL-amino-3-phosphonopropionic acid (AP3), or DL-amino-4-phosphonobutyric acid, suggesting that activation of non-N-methyl-D-aspartate (non-NMDA), NMDA, and metabotropic glutamate (Glu) receptors is involved in the generation and maintenance of the persistent depolarization. Among these Glu receptor antagonists, only CNQX or AP5 was able to reduce dose dependently the level of depolarization, suggesting that Ca2+ influx via both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid/kainate type II receptors and NMDA receptors contributes to the membrane dysfunction. trans-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) did not affect the peak potential of the persistent depolarization, but it dose-dependently restored the membrane potential. AP3 antagonized the protective action of t-ACPD. The membrane potential also recovered after reintroduction when the slice was pretreated by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester, ryanodol 3-(1H-pyrrole-2-carboxylate), 8-(diethylamino)octyl-3,4,5-trimethoxybenzoate hydrochloride, and procaine, suggesting that raised [Ca2+]i from Ca2+-induced Ca2+ release pool contributes to the membrane dysfunction. It, therefore, is concluded that raised [Ca2+]i has a dominant role in causing irreversible changes. The increase in [Ca2+]i during the persistent depolarization may be the result of Ca2+ entry via both a leaky membrane and Glu-activated receptor channels as well as Ca2+ released from internal stores.

Animals↗
PubMed1997

Phenobarbital molecularly imprinted polymer selectively binds phenobarbital.

Molecularly imprinted polymer (MIP) was prepared against phenobarbital using methacrylic acid as the functional monomer and ethylene glycol dimethacrylate as the cross linking monomer. We analyzed the recognition properties of the phenobarbital MIP. In some organic solvents, imprinted polymer showed selective binding to phenobarbital. Two dissociation constants of binding were calculated by Scatchard plot analyses; Kd values were 1.8, 121.7 microM, and the number of binding sites was 8.3, 92.3 mumol/g MIP in toluene-heptane-acetic acid (25 : 75 : 1, v/v), respectively. The relationship between the binding affinity to phenobarbital MIP and the polarity of the solvent system, as well as the structure of the template molecule is also discussed.

Cross-Linking Reagents↗
PubMed1997

[Ca2+ dynamics in glial cells].

Because glial cells have been characterized by electrophysiological studies as being silent and inactive, neuroscientists have overlooked the roles of these cells in the dynamic function of the central nervous system. Recent measurements of intracellular Ca2+ concentration, however, revealed the dynamic and active features of the glial cells. Some populations of these cells gave rise to increase in intracellular Ca2+ concentration by stimulation with neurotransmitters such as glutamate, acetylcholine, serotonin, noradrenaline and histamine through the activation of specific neurotransmitter receptors distributed on the glial cells. Although the roles of the increased intracellular Ca2+ concentration in glial cells have not been elucidated, these properties suggested the functional participation of glial cells in synaptic modulation and plasticity.

Animals↗
PubMed1997

Peculiar archaea found in Japanese paddy soils.

Archaeal 16S rDNA clones retrieved from paddy soil DNA were sequenced. Among 100 clones, 88 clones were assigned to methanogens and nine clones were assigned to crenarchaeota. However, three of the nine clones were phylogenetically far from the cultured crenarchaeota and closely related to marine planktonic archaea. The other three clones showed extremely novel 16S rDNA sequences and were phylogenetically far from both Crenarchaeola and Euryarchaeota. This paper reports the ubiquitous presence of crenarchaeotal and extremely novel clones in paddy soils.

Archaea↗
PubMed1997

[Changes in porphyrin metabolism of mice given beryllium and/or zinc].

Beryllium chloride and/or zinc chloride were intraperitoneally injected into mice. The amount of beryllium (Be) injected corresponded to 1/10th of the LD50 dose intravenously administered. The amount of zinc (Zn) injected was the same as Be. The changes in porphyrin metabolism of the mice were studied. Delta-aminolevulinic acid dehydratase (ALA-D) activities in the blood were found to increase significantly in Zn and BeZn groups when compared to the control level. The blood porphobilinogen deaminase (PBG-D) activity in the Zn group was slightly less than that in the controls. The ALA-D and PBG-D activities in liver were higher in the Be and BeZn groups than in the controls. The splenic ALA-D activities were significantly higher in the Zn and BeZn groups than in the control and Be groups. The splenic PBG-D activities were markedly higher in the Be and/or Zn groups than in the controls. An increase in ALA-D activities in the blood and spleen was observed in the BeZn group, together with an increase in ALA-D activities caused by Zn administration. Furthermore, the increase in PBG-D activities in liver and spleen was observed in the Be and/or Zn groups. The results suggested that chemical similarity between Be and Zn brought about these phenomena.

Animals↗
PubMed1997

Cellular localization of thrombopoietin mRNA in the liver by in situ hybridization.

The expression of thrombopoietin (TPO) mRNA is observed in several tissues, including liver, kidney, brain, skeletal muscle, intestine, spleen, and bone marrow. Among these organs, the highest expression of TPO mRNA is detected in the liver. We identified cells producing TPO by means of in situ hybridization of adult rat liver using digoxigenin-11-UTP-labeled cRNA probes. We found that the cells expressing TPO mRNA also expressed serum albumin mRNA. TPO mRNA was detected in parenchymal cells (hepatocytes) but not in non-parenchymal cells (including endothelial cells, epithelial cells, and so forth). To determine the location of TPO expression in embryogenesis, sections of fetal mice were further analyzed by in situ hybridization. TPO mRNA was detected only in hepatocytes of fetal liver, which was also the major site of hematopoiesis. The expression of TPO mRNA in fetal liver was observed from 12.5 days postcoitus. Northern blot analysis showed that mouse liver transcribed the same size of TPO mRNA in the fetus and in the adult. These results clearly demonstrate that hepatocytes are the primary site of TPO production in the liver from fetus to adult.

Animals↗
PubMed1997

[A study on the role of ultrasonography in antenatal care in Thailand with focus on the appropriate technology].

The authors investigated the state of antenatal care, outcome of deliveries and use of ultrasonography at the Maternal and Childhood Health Hospital in Khonkane province, Thailand. The study was conducted before (stage I) and after (stage II) the introduction of the second ultrasonographic equipment in an attempt to set up a proper standard of technological level of clinical laboratory services and to investigate the usefulness of introducing ultrasonography into the prenatal care in developing countries. As a result, about 60% of first antenatal visits were in their second or third trimester, about 80% of pregnancies terminated by normal vaginal deliveries, parity, rate of cesareans sections and pre-term labors were not significantly different in both stages. Ultrasonography was performed on 16% of the first antenatal visits in stage I, while, in stage II, it was performed on 31.3% of them. Ultrasonography was used most frequently to determine the gestational age and presentation of the fetus in both years (70.3% and 79.1% respectively in stage I and stage II). In most of the cases, ultrasonography was performed only once during the gestation. Thus, it was proved that technical training must be provided with introduction of new equipment to medical facilities and utilization of medical technologists for ultrasonography was another concern in developing countries. Beside, it was important to determine the proper period during the gestation when ultrasonography should be applied and to adopt an effective public health service including health education and health insurance to promote antenatal visits in time during the proper periods.

Developing Countries↗
PubMed1997

[In vitro combination effect of vancomycin and carbapenems against carbapenem-resistant MRSA].

We determined in vitro combined effects of vancomycin (VCM) plus carbapenems (CRBs) on 12 methicillin-resistant Staphylococcus aureus (MRSA) which are resistant to CRBs. Combinations of VCM plus imipenem (IPM) and VCM plus panipenem (PAPM) and VCM plus meropenem (MEPM) indicated synergistic effects, fractional inhibitory concentration (FIC) indices of < or = 0.05, against 67%, 75%, 67% of the strains, respectively. Against forty two percent of strains tested, 1 MIC of VCM was equal to 1 MBC, and similarly, IPM, PAPM and MEPM had 1 MIC = 1 MBC against 42%, 67% and 75% of the strains tested, respectively. Combinations of VCM plus IPM and VCM plus PAPM and VCM plus MEPM showed synergistic effects, hence a fractional bactericidal concentration (FBC) index of < or = 0.50, against 42%, 50%, 75% of the strains, respectively, and the combination of VCM plus MEPM was most synergistic. These results suggest that combination therapy of VCM with CRB is useful for the treatment of MRSA infection in patients with renal dysfunction.

Anti-Bacterial Agents↗
PubMed1997

Pharmacokinetic and pharmacodynamic evaluation of central effect of the novel antiallergic agent betotastine besilate.

Betotastine besilate (betotastine CAS 125602-71-3, TAU-284) is a novel antiallergic agent with histamine H1 receptor antagonistic activity. As the classical antihistamines are known to produce drowsiness, the present study was conducted to assess a possible influence of betotastine on the central nervous system (CNS). Measurement of the drug concentration in brain and plasma after i.v. administration revealed that betotastine, as well as cetirizine and epinastine, poorly penetrate into the CNS, while terfenadine do so slightly more and ketotifen remarkably more. In vitro receptor binding assays demonstrated that betotastine is a highly specific histamine H1 receptor ligand, having no significant binding affinity for histamine H3, adrenergic alpha 1, alpha 2, beta, dopamine D2L, serotonin 5-HT2, muscarinic, and benzodiazepine receptors. On global behavior of mice, oral administration of betotastine did not produce any marked changes at the doses of 100-1000 mg/kg, but suppressed huddling behavior at 1000 mg/kg and caused slight mydriasis at 300 mg/kg and more. Betotastine did not significantly affect spontaneous motor activity (SMA) and hexobarbital-induced anesthesia in mice up to 300 mg/kg p.o. In the sleep-wakefulness pattern of cats, it reduced the total duration of sleep at 10 mg/kg p.o., but did not show significant effect at 30 and 100 mg/ kg p.o. Cetirizine showed a similar profile as betotastine in these experiments, whereas ketotifen and epinastine induced sedative signs or toxic symptoms in lower doses, and terfenadine affected SMA and the anesthesia at a high dose. These results suggest the very low liability of betotastine to produce sedative side-effect in a therapeutic dose range.

Animals↗
PubMed1996

Imaging of Ca2+/calmodulin-dependent protein kinase II activity in hippocampal neurones.

Our aim was to visualize the dynamic features of Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity. In order to do so, we synthesized a new reagent by conjugating a fluoroprobe, 6-acryloyl-2-dimethylaminonaphthalene (acrylodan), to syntide 2, a specific peptide substrate for CaMKII. In cell-free conditions, the conjugate was found to be an effective indicator of calmodulin activation by Ca2+ and the subsequent activation of CaMKII. The reagent is cell-permeable and can stain living cells when bath-applied. Using this technique we were able to obtain fluorescence images of stained cells and analyse the dynamic features of CaMKII inside the cells by means of image processing. Regional heterogeneity of CaMKII activation in cultured hippocampal neurones was seen following L-glutamate administration.

Animals↗
PubMed1996

A facilitatory effect on the induction of long-term potentiation in vivo by chronic administration of antisense oligodeoxynucleotides against catalytic subunits of calcineurin.

A rise in Ca2+ concentration at postsynaptic sites provides an initial step in inducing both the long-term potentiation (LTP) and long-term depression (LTD) in the CA1 region of the hippocampus. LTP induction requires the activation of Ca(2+)-sensitive protein kinases following the rise in Ca2+. By contrast, the activity of protein phosphatase(s) appears to be critical to induce LTD. Here we demonstrate that inhibition of the synthesis of calcineurin A alpha and A beta, catalytic subunits of Ca2+/calmodulin- (CaM) dependent protein phosphatase, reduces the threshold of induction for commissural-CA1 LTP in anesthetized rats. In rats administered antisense oligodeoxynucleotides (ODNs) against calcineurin A alpha and A beta intraventricularly for 7 days, a brief tetanic stimulation to the CA3 region, which in the control case was below threshold for the induction of LTP, now produced a long-lasting increase in both the EPSP slope and the amplitude of population spike recorded from the commissural-CA1 pathway. Western blot analysis of calcineurin showed that the threshold reduction was accompanied by a selective decrease in the protein levels in the hippocampus. Thus our study provides direct evidence that calcineurin per se has an antagonizing role in LTP induction. Complementary experiments with the selective calcineurin inhibitor, FK506, also showed the reduction of LTP threshold in a dose-dependent manner. These results, together with previous studies, support the hypothesis that the quantitative phosphorylation level of critical intracellular proteins determines whether the synaptic efficacy will increase or decrease after the activity-dependent rise in postsynaptic Ca2+.

Animals↗