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Biomedical subjects

T Irie

Publications and source records attributed to T Irie.

At least 19 recordsLinked to original sources

The role of sex hormones in the kinetics of chondrocytes in the growth plate. A study in the rabbit.

Sex hormones play important roles in the regulation of the proliferation, maturation and death of chondrocytes in the epiphyseal growth plate. We have investigated the effects of male castration on the cell kinetics of chondrocytes as defined by the numbers of proliferating and dying cells. The growth plates of normal rabbits and animals castrated at eight weeks of age were obtained at 10, 15, 20 and 25 weeks of age. Our study suggested that castration led to an increase in apoptosis and a decrease in the proliferation of chondrocytes in the growth plate. In addition, the number of chondrocytes in the castrated rabbits was less than that of normal animals of the same age.

Animals↗

Study for imaging of inside bone using FM-chirp pulse compression system.

We measured the attenuation of ultrasound in animal bone in vitro, and determined successfully the correct dynamic range for the detection of echo signals from inside the bone. It was possible to display a B-mode image of a 6-mm thick porcine rib bone using a high frequency (5 MHz) transducer. However, it was difficult to obtain the image of a large bone (20-mm thick femur). This paper describes a possibility of the improvement for the detection of echoes from inside the bone using the FM-chirp pulse. An ultrasonic wave generator that generates the FM-chirp pulse for a frequency range of 100 KHz to 5 MHz was fabricated. And the pulse was transmitted from a transducer and received by a hydrophone in the water. The received waveform and the frequency spectrum were displayed on an oscilloscope. We measured the amplitude spectrum of the received waves before and after inserting a sample bone between the transducer and the hydrophone. In the experiment, three types of focused transducers (0.5, 1 and 2.25 MHz) and three kinds of sample bones (spine, femur and rib of a pig) were used. From the results of the measurement, we could find the useful information for imaging of inside the bone.

Animals↗

Gene expression profiling of mouse condylar cartilage during mastication by means of laser microdissection and cDNA array.

Little is known about the mechanisms of mandibular condylar growth. In this study, gene expression in the mandibular condylar cartilage of young post-natal mice was monitored by means of a cDNA microarray, real-time PCR, and laser microdissection before and after the initiation of mastication (newborn, 7 days, 21 days, initiation of mastication, and 35 days). Insulin-like growth factor-1 (IGF-I), transforming-growth-factor-beta-2 (TGFbeta2), and aggrecan mRNAs were clearly expressed at 21 days, while the expression of osteopontin mRNAs was most clear at 35 days. Parathyroid-hormone-related protein (PTHrP), Indian-hedgehog (Ihh), and insulin-like growth factor-2 (IGF-2) mRNAs were clearly expressed during lactation (newborn and 7 days). Heat-shock-protein 84 (HSP-84) and heat-shock-protein 86 (HSP-86) were clearly expressed at 35 days. These results revealed that gene expression changed during mandibular condylar cartilage growth, and that, interestingly, these changes coincided with the initiation of mastication.

Aggrecans↗

Serial Analysis of Gene Expression (SAGE) of Magnaporthe grisea: genes involved in appressorium formation.

Treatment with cyclic AMP (cAMP) induces appressorium formation in the phytopathogenic fungus Magnaporthe grisea, the causative agent of rice blast disease. In a search for the M. grisea genes responsible for appressorium formation and host invasion, SAGE (Serial Analysis of Gene Expression) was carried out using mRNA isolated from fungal conidia germinating in the presence and absence of cAMP. From cAMP-treated conidia 5087 tags including 2889 unique tags were isolated, whereas untreated conidia yielded 2342 unique tags out of total of 3938. cAMP treatment resulted in up- and down-regulation of genes corresponding to 57 and 53 unique tags, respectively. Upon consultation of EST/cDNA databases, 22 tags with higher representation in cAMP-treated conidia were annotated with putative gene names. Furthermore, 28 tags corresponding to cAMP-induced genes could be annotated with the help of the recently published genome sequence of M. grisea. cAMP-induced genes identified by SAGE included many genes that have not been described so far, as well as a number of genes known to be involved in pathogenicity, e.g. MPG1, MAS1 and MAC1. RT-PCR of 13 randomly selected genes confirmed the SAGE results, verifying the fidelity of the SAGE data.

Base Sequence↗

The amygdala and Alzheimer's disease: positron emission tomographic study of the cholinergic system.

The primary transmitter deficit is cholinergic in Alzheimer's disease (AD), and the amygdala receives a major cholinergic projection from the nucleus basalis of Meynert (Ch4), which may play an important role in the retention of affective conditioning and/or memory consolidation. We measured brain acetylcholinesterase (AChE) activity in 54 patients with AD and in 22 normal controls by positron emission tomography and N-[(11)C]methylpiperidin-4-yl acetate to characterize the cholinergic pathology in AD. The k(3) values were calculated as an index of AChE activity in a three-compartment model analysis using the metabolite-corrected arterial input function. The k(3) values were highly significantly reduced by 20% in the cerebral neocortex (P <0.0001 in the two-tailed t test), 14% in the hippocampus (P <0.001), and 33% in the amygdala (P <0.0001) in AD patients compared with normal controls. The k(3) values were significantly correlated with the Mini-Mental State Examination scores in both the cerebral cortex (P <0.001) and the amygdala (P <0.05) in AD patients, supporting the cholinergic hypothesis of cognitive dysfuncion in AD. Further studies are required, however, to elucidate the specific role of the cholinergic deficit in the amygdala in the emotional and behavioral symptoms in AD.

Aged↗

Protective effect of sulfobutyl ether beta-cyclodextrin on DY-9760e-induced hemolysis in vitro.

The hemolytic behavior of a novel cytoprotective agent, DY-9760e (3-[2-[4-(3-chloro-2-methylphenyl)-1-piperazinyl]ethyl]-5,6-dimethoxy-1-(4-imidazolylmethyl)-1H-indazole dihydrochloride 3.5 hydrate) was investigated using rabbit erythrocytes. Further, the effects of water-soluble cyclodextrin derivatives, such as 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and sulfobutyl ether of beta-cyclodextrin (SBE-beta-CyD), on the hemolytic activity of DY-9760e were studied. DY-9760e induced hemolysis at concentrations >0.2-0.3 mM in phosphate buffered saline (PBS) of pH 4.0 and 6.0, where DY-9760e is predominantly in dicationic and monocationic forms, respectively. The hemolytic activity of the monocationic DY-9760e was higher than that of the dicationic species, and the hemolysis at pH 4.0 involved the formation of methemoglobin. DY9760e induced the morphological change of erythrocytes towards membrane invagination at both pH 4.0 and 6.0. SBE7-beta-CyD significantly suppressed the DY-9760e-induced hemolysis and morphological change at both pH 4.0 and 6.0, as well as the formation of methemoglobin at pH 4.0. On the other hand, HP-beta-CyD suppressed only the hemolysis, but neither the morphological change nor the formation of methemoglobin. In addition, the inhibitory effect of SBE7-beta-CyD on the hemolysis was greater than that of HP-beta-CyD. The superior inhibitory effect of SBE7-beta-CyD on the DY-9760-induced hemolysis, the morphological change, and the formation of methemoglobin may be attributable to the formation of a stable inclusion complex with DY-9760e and to the weaker hemolytic activity of SBE7beta-CyD than HP-beta-CyD. These results suggest potential use of SBE7-beta-CyD as a parenteral carrier for DY-9760e.

Animals↗

Protective effects of estradiol against amyloid beta protein-induced inhibition of neuronal Cl(-)-ATPase activity.

Low concentrations of amyloid beta proteins (Abetas, 1-10 nM) were recently demonstrated to reduce Cl(-)-ATPase activity in parallel with an increase in the intracellular Cl(-) concentration ([Cl(-)]i) and decreases in plasma membrane phosphorylated phosphatidylinositol (PIP and PIP2) levels in cultured rat hippocampal neurons. In this study, 17 beta-estradiol (estradiol) at a therapeutic concentration (1.8 nM) for Alzheimer's disease was found to block these Abeta (Abeta25-35)-induced changes. This protective effect of estradiol on Cl(-)-ATPase activity was antagonized by a pure estrogen receptor antagonist, ICI182780 and inhibitors for cyclic GMP-dependent protein kinase (PKG) (KT5823), Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) (KN62) and phosphatidylinositol (PI) 4-kinase (wortmannin and quercetin). Estradiol recovered Abeta-induced decreases in plasma membrane phosphoinositide (PIP and PIP2) levels, this effect being inhibited by KT5823 and KN62. Glutamate toxicity was augmented in neurons with elevated [Cl(-)]i either by Abeta-treatment or carbachol+KCl+LiCl-treatment. The increased glutamate toxicity in the Abeta-treated neurons was attenuated by estradiol. Thus, a therapeutic concentration of estradiol protected Abeta-treated neurons against inhibition of Cl(-)-ATPase activity and an increase in [Cl(-)]i through its receptor, probably via PKG- and CaMKII(-)mediated recovery of PI4P formation. Elevated [Cl(-)]i may be related to enhancement of glutamate toxicity.

Adenosine Triphosphatases↗

Improvement of some pharmaceutical properties of DY-9760e by sulfobutyl ether beta-cyclodextrin.

The interaction of DY-9760e, a novel cytoprotective agent, with sulfobutyl ether beta-cyclodextrin (SBE-beta-CyD) in phosphate buffered saline (PBS) at various pH and ionic-strengths was studied by spectroscopic methods and the solubility method, and the results were compared with that of 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD). The circular dichroism (CD) spectroscopic studies suggested that both beta-CyDs form the inclusion complexes with DY-9760e in a molar ratio of 1:1, and the interaction of DY-9760e with SBE-beta-CyD is much stronger than that with HP-beta-CyD at any pH studied, in terms of a synergetic effect of hydrophobic and electrostatic interactions. The different intermolecular interaction between the SBE-and HP-beta-CyD complexes was clearly reflected in the stability constant (K'), e.g. the different dependence of K' value on pH and ionic strength of solutions. 1H- and 13C-NMR studies suggested that HP-beta-CyD interacts preferably with the benzene ring of DY-9760e, whereas SBE-beta-CyD interacts not only with the benzene ring via hydrophobic interaction but also with the piperazine ring of the drug via electrostatic interaction. The solubilizing ability of SBE-beta-CyD against DY-9760e was much greater than that of HP-beta-CyD at any pH studied. Furthermore, SBE-beta-CyD markedly suppressed the photo-degradation of DY-9760e in aqueous solution and reduced the adsorption of DY-9760e from PBS to polyvinyl chloride (PVC) tubes after incubation. The results suggest that SBE-beta-CyD is useful in preparing parenteral solutions of poorly water-soluble drugs with positive charge such as DY-9760e.

Adsorption↗

An anxiolytic agent, dihydrohonokiol-B, inhibits ammonia-induced increases in the intracellular Cl(-) of cultured rat hippocampal neurons via GABA(c) receptors.

The effects of an anxiolytic honokiol derivative, dihydrohonokiol-B (DHH-B) [3'-(2-propenyl)-5-propyl-(1,1'-biphenyl)-2,4'-diaol], on ammonia-induced increases in the intracellular Cl(-) concentration ([Cl(-)](i)) were examined using primary cultured rat hippocampal neurons. DHH-B (1-100 ng/ml), but not an inactive isomer of honokiol, magnolol (100 ng/ml), dose-dependently inhibited the ammonia-induced increases in [Cl(-)](i) without any changes in the control [Cl(-)](i). Such an effect of DHH-B was blocked by a gamma-aminobutylic acid A (GABA(A)) and GABA(C) Cl(-) channel blocker, 100 microM picrotoxin, and a GABA(C) receptor blocker, 10 microM (1,2,5,6-tetrahydropyridine-4-yl)methylphosphinic acid, but not by a GABA(A) receptor blocker, 10 microM bicuculline. Further, a GABA(C) receptor agonist, 200 microM cis-4-aminocrotonic acid, but not a GABA(A) receptor agonist, 10 microM muscimol, mimicked the effect of DHH-B. Thus, DHH-B appears to protect neurons from the ammonia-induced increases in [Cl(-)](i) through GABA(C) receptor stimulation.

Ammonia↗

PKCtheta II, a new isoform of protein kinase C specifically expressed in the seminiferous tubules of mouse testis.

Protein kinase C (PKC) theta, a Ca(2+)-independent isoform of PKC, has been known to be expressed in skeletal muscle and T cells. In the present study, we isolated and characterized a smaller transcript expressed in the mouse testis, the cDNA of which is referred hereafter as PKCthetaII and the original PKCtheta as PKCthetaI. The cDNA clone of PKCthetaII has 2184 base pairs and 464 amino acids in the possible open reading frame, consisting of the 5' unique sequence of 20 amino acids and the PKCthetaI sequence of 444 amino acids. Genomic DNA analysis revealed that transcription of PKCthetaII is initiated from the PKCthetaII-specific exon, which is located between exons 7 and 8 of the PKCtheta gene, indicating that alternative splicing is the mechanism by which PKCthetaII is generated. PKCthetaII is expressed exclusively in the testis in an age-dependent manner with sexual maturation. In situ hybridization and reverse transcription-polymerase chain reaction of microdissected tissues clearly demonstrated that PKCthetaII is expressed in the seminiferous tubules of the mouse testis. Consistent with its molecular structure lacking the C1 regulatory domain, PKCthetaII is constitutively active as determined by an in vitro kinase assay, being independent of PKC activators, e.g. phosphatidylserine and phorbol ester. PKCthetaII may play a crucial role in spermatogenesis or some related function of the testis.

Alternative Splicing↗

Effect of donepezil on brain acetylcholinesterase activity in patients with AD measured by PET.

Acetylcholinesterase (AChE) activities in the brain of three patients with AD were measured once before and once during donepezil treatment (5 mg/d in two patients, 3 mg/d in one patient) using PET and N-[11C]methylpiperidin-4-yl acetate. Donepezil reduced k(3) values, an index of AChE activity, in the cerebral cortex by 39 +/- 5%. All patients showed some degree of symptomatic improvement, and it was concluded that this improvement was likely caused by improved cholinergic activity by inhibition of AChE in the brain.

Acetylcholinesterase↗

Comparative studies of the enhancing effects of cyclodextrins on the solubility and oral bioavailability of tacrolimus in rats.

The enhancing effects of cyclodextrins (CyDs) on the solubility, the dissolution rate, and the bioavailability of tacrolimus after oral administration to rats were examined and compared with those after administration of a PROGRAF capsule containing the solid dispersion formulation of tacrolimus. Here we used natural CyDs and the hydrophilic beta-CyD derivatives; that is, randomly methylated-beta-cyclodextrin (RM-beta-CyD), heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD), 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD), and sulfobutyl ether beta-cyclodextrins (SBE-beta-CyDs). Of the natural CyDs, the solubility of tacrolimus increased in the addition of beta-CyD, indicating that the cavity of beta-CyD comfortably fits the drug. Of the beta-CyD derivatives, DM-beta-CyD had the greatest solubilizing activity and gave the A(p) type phase solubility curve as defined by Higuchi and Connors, suggesting the formation of higher-order complexes. The result of van't Hoff plot suggests that the enthalpy is dominant for the complexation of tacrolimus with DM-beta-CyD. The dissolution rate of tacrolimus was markedly augmented by the complexation with DM-beta-CyD, reflecting its solubilizing activity. An in vivo study revealed that DM-beta-CyD increased the bioavailability of tacrolimus with low variability in the absorption after oral administration of the tacrolimus suspension to rats. The present results suggest that DM-beta-CyD is particularly useful in designing oral preparations of tacrolimus with an enhanced bioavailability and a reduced variability in absorption.

Administration, Oral↗

Neuroendocrine small cell carcinoma of the uterine cervix showing polypoid growth and complicated by pregnancy.

BACKGROUND: Neuroendocrine small cell carcinoma of the uterine cervix is an aggressive disease, and it rarely is complicated by pregnancy. CASE: A polypoid tumor was found in the uterine cervix in a 27-year-old Japanese woman at 27 weeks of gestation. No polyp had been detected at 14 weeks of gestation. The polyp was excised and diagnosed as neuroendocrine small cell carcinoma by histological examination, including Grimelius, neuron-specific enolase, and chromogranin staining. A healthy infant was born by cesarean section at 29 weeks of gestation: this was followed by radical hysterectomy with pelvic lymphadenectomy. After surgery, four cycles of combination chemotherapy with cisplatin and etoposide were administered, and the patient is disease-free as of 13 months after surgery. CONCLUSION: When a polypoid lesion is found, especially when it demonstrates rapid growth, it may be necessary to excise and histologically examine the polyp even during pregnancy.

Adult↗

Dose-finding phase I study of simultaneous weekly infusion with doxorubicin and docetaxel in patients with advanced breast cancer.

BACKGROUND: Combination therapy with doxorubicin (DOX) and docetaxel (DOC), given 3 weeks apart, is one of the standard regimens used for treating metastatic breast cancer, but it frequently generates febrile neutropenia. To find a safer regimen with less myelotoxicity and the appropriate dose intensity, we conducted a phase I study of simultaneous weekly infusion with DOX and DOC. METHODS: Twenty-five patients with advanced breast cancer were treated with an intravenous push-injection of DOX that was immediately followed by a 1-h infusion of DOC. This was repeated every week for at least 6 weeks. The premedication employed was three 4-mg doses of dexamethasone every week. Patients were divided into four groups for which the doses of DOX and DOC were escalated in 5-mg/m2 increments. RESULTS: In the 18 patients who were treated with DOX 15 or 20 mg/m2 and DOC 25 mg/m2, or lower, the regimen was found to be tolerable, without febrile episodes. The regimen with 20 mg/m2 of DOX and 30 mg/m2 of DOC was the maximum tolerated dose. Other indications of grade 3 toxicity included asthenia in 4% of patients, anorexia in 8%, and vomiting in 8%. Of the 25 patients, 14 had a partial response. The overall response rate was 56% (95% confidence interval [CI], 35% to 77%). The recommended dose for further trial was 20 mg/m2 of DOX and 25 mg/m2 of DOC. CONCLUSION: Simultaneous weekly infusion with DOX and DOC was feasible, with modest neutropenia and preserved dose intensity. This regimen may be helpful in the management of patients with advanced breast cancer.

Adult↗

Efficient transformation of filamentous fungus Pleurotus ostreatus using single-strand carrier DNA.

The effects of carrier DNAs on the transformation of the basidiomycete Pleurotus ostreatus were analyzed. When lambda phage DNA was added to a transformation mixture containing protoplasts and CbxR vector plasmid, an increased number of drug-resistant transformants was observed on a screening plate containing 2 microg carboxin/ml. The highest efficiency (about 200 transformants/microg vector plasmid) was obtained by the addition of heat-denatured lambda DNA, which gave yields approximately 50-fold higher than the control experiment without a carrier DNA. To our knowledge, this is the first report on enhancement in transformation efficiency of fungal protoplasts by single strand carrier DNA.

Bacteriophage lambda↗

Homologous expression of recombinant manganese peroxidase genes in ligninolytic fungus Pleurotus ostreatus.

Pleurotus ostreatus is a white-rot fungus known as an efficient degrader of lignin and also various organo-pollutants. Using a DNA-mediated transformation system, a molecular breeding approach to isolate over-producers of a manganese peroxidase isozyme, MnP3, was carried out. Recombinant mnp3 constructs under the control of P. ostreatus sdi1 expression signals were introduced into the wild-type P. ostreatus strain by co-transformation with a carboxin-resistant vector plasmid, pTM1. One of the recombinants obtained by a mating between two monokaryotic transformants, TMG9-C1, showed a several times higher level of MnP activity than the wild-type control in the early stage of liquid culture. Predominant transcription of the recombinant mnp3 in the strain was demonstrated by RT-PCR experiments. This is the first report of a genetically modified P. ostreatus strain with an expression system for recombinant genes.

Base Sequence↗

Stable transformation of Pleurotus ostreatus to hygromycin B resistance using Lentinus edodes GPD expression signals.

It was reported that Pleurotus ostreatus was transformed unstably using recombinant plasmids containing a hygromycin B phosphotransferase gene (hph) under the control of Aspergillus nidulans expression signals, and that the plasmids were maintained extrachromosomally in the transformants. Here we report a stable and integrative transformation of the fungus to hygromycin B resistance, using a recombinant hph fused with Lentinus edodes glyceraldehyde-3-phosphate dehydrogenase expression signals. Restriction-enzyme-mediated integration (REMI) was also tried and increased the transformation efficiency about ten-fold.

Anti-Bacterial Agents↗