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M Yoshikawa

Publications and source records attributed to M Yoshikawa.

At least 289 records · Page 16Linked to original sources
PubMed1997

Immunohistochemical localization of D-aspartate in the rat pineal gland.

Specific polyclonal antibody was raised against D-aspartate (D-Asp) which had been conjugated to glutaraldehyde and was purified by affinity chromatography. Immunohistochemical staining of rat pineal gland with the antibody demonstrated the presence of D-Asp in the cytoplasm of pinealocytes, the predominant cell type in this gland. D-Asp immunoreactivity was more evident in the distal region than in the proximal region of the gland. Pinealocytes in the distal region are presumably involved in the synthesis and secretion of the pineal hormone, melatonin, and the results of staining may indicate some yet unknown role of D-Asp in the regulation of melatonin secretion.

Animals↗
PubMed1997

The structure and function of a soybean beta-glucan-elicitor-binding protein.

beta-Glucan elicitor (GE), released from the cell wall of the phytopathogenic fungus Phytophthora megasperma by soybean glucanases, causes defense reactions in soybean. A GE-binding protein (GEBP) was purified from the membrane fraction of soybean root cells, and its cDNA was isolated. Expression of the cDNA clone in tobacco suspension cultured cells and in Escherichia coli conferred GE-binding activity to both. An antibody against the recombinant protein was found to inhibit the GE binding with the soybean cotyledon membrane fraction as well as the resulting accumulation of phytoalexin. Immunolocalization assays indicated that the GEBPs are located in the plasma membrane of root cells. These results suggest that the cDNA encodes a GE receptor and may mediate the signaling of the elicitor.

ATP-Binding Cassette Transporters↗
PubMed1997

Detection of cyclin D1 (bcl-1, PRAD1) overexpression by a simple competitive reverse transcription-polymerase chain reaction assay in t(11;14)(q13;q32)-bearing B-cell malignancies and/or mantle cell lymphoma.

In mantle cell lymphoma, the t(11;14)(q13;q32) and its molecular counterpart, bcl-1 rearrangement, are consistent features and lead to cyclin D1 (bcl-1, PRAD1) proto-oncogene overexpression. In order to detect cyclin D1 overexpression, we developed a simple assay involving a reverse transcription followed by competitive polymerase chain reaction (PCR). A single upstream primer was derived from a homologous region between cyclin D1 and the other D-type cyclins, cyclins D2 and D3, while three downstream primers were specific to their respective D-type cyclins. Because the upstream primer was shared in PCR amplification of the three sequences, each PCR product served as a competitor and the quantification of the target was made by comparison of the intensity of the three products. With this assay we analyzed 45 hematopoietic cell lines and 40 clinical specimens. Cyclin D1 was rarely expressed in lymphoid cell lines except in t(11;14)(q13;q32)-bearing B-cell malignancies and/or mantle cell lymphoma, which expressed cyclin D1 predominantly. In myeloid cell lines, the levels of cyclin D1 expression varied and never exceeded the sum of cyclin D2 and D3 levels. Cyclin D3 was ubiquitously expressed while cyclins D1 and D2 were differentially used. The observations suggest that human cyclin D3 may play a fundamental role in hematopoiesis and that cyclins D1 and D2 may have different lineage- or differentiation-dependent functions. With this assay, small aliquots of clinical specimens such as 100 microL peripheral blood were enough to detect cyclin D1 overexpression without a well-controlled standard. The technique was validated as highly comparable with Northern analysis. This rapid and reliable detection of cyclin D1 overexpression may have practical clinical utility in the analysis and management of B-cell malignancies.

Binding, Competitive↗
PubMed1997

Postnatal ontogeny of striatal-enriched protein tyrosine phosphatase (STEP) in rat striatum.

The present study was undertaken to examine developmental change in expression of striatal-enriched protein tyrosine phosphatase (STEP) in the postnatal striatum of rats. For this purpose, immunohistochemical staining and transimmunoblotting analyses were carried out using a cDNA-generated polyclonal antibody to the STEP with a molecular weight of 46 kDa. Immunostaining showed that in neonatal striatum STEP-immunoreactivity was found in discrete patches composed of many immature cells, which corresponded to the tyrosine hydroxylase-immunopositive "dopamine islands." With development there was an increase in staining intensity and in the number of positively reacting cells. By 4 weeks postnatally, STEP-immunoreactivity was almost homogeneously distributed throughout the striatum, as was seen at the adult stage. Immunoblotting analysis showed that STEP protein expression abruptly increased from 2 to 4 weeks postnatally when it reached the adult level. These findings suggest that STEP is involved in development and maturation of the striatal neurons.

Animals↗
PubMed1997

GABA receptor agonist promotes reformation of the striatonigral pathway by transplant derived from fetal striatal primordia in the lesioned striatum.

Striatal lesions are known to cause the anterograde transneuronal degeneration of the substantia nigra pars reticulata (SNr) neurons in consequence to loss of GABAergic inhibitory striatonigral efferents. The present study was undertaken to examine whether long-term intraventricular administration of the GABA agonist muscimol could promote reformation of the striatonigral pathway arising from transplants by rescuing host SNr neurons from transneuronal death in rats with striatal ischemic lesions. Compared to nongrafted rats with striatal lesions, (i) a prominent axonal projection from the transplants to the ipsilateral substantia nigra, (ii) a significant increase in number of survived neurons in the ipsilateral SNr, and (iii) a significant reduction in number of apomorphine-induced turning behaviors were found in grafted animals with muscimol infusion, but not in those without muscimol administration. These findings suggest that preservation of the host target neurons for grafted cells may increase an efficacy of cerebral implants in establishment of the host-graft fiber connections, possibly, leading to functional restoration.

Animals↗
PubMed1997

Spiral computed tomography with 3-dimensional reconstruction for the diagnosis of tracheobronchial stenosis.

We report on the usefulness of spiral computed tomography (CT) with 3-dimensional (3D) reconstruction in the diagnosis of tracheobronchial abnormalities based on three cases of children with congenital tracheobronchial strictures. Images were reconstructed using a curved planar reformat and shaded surface display. The images obtained from our three cases of tracheal stenosis, subglottic stenosis and tracheobronchial strictures were extremely clear. Spiral CT with 3D reconstruction provides excellent anatomic delineation of the tracheobronchial airway, and is safe and less invasive than tracheobronchography.

Bronchial Diseases↗
PubMed1997

HDL3 exerts more powerful anti-oxidative, protective effects against copper-catalyzed LDL oxidation than HDL2.

OBJECTIVE: To evaluate which HDL subfraction, HDL2 or HDL3 exerts the greater preventive effect on the Cu(2+)-induced LDL oxidation. METHODS: LDL was incubated for 6 h with 2.5 microM Cu2+ in phosphate-buffered saline alone, or in the presence of HDL2 or HDL3 at various protein concentrations. Each sample was subjected to agarose gel electrophoresis, and the amount of lipid hydroperoxide in each sample of LDL was measured. RESULTS: There was no significant difference in the levels of LPO between the LDL and LDL + HDL2 cases, whereas a significant reduction was apparent with LDL + HDL3. Both HDL2 and HDL3 significantly inhibited oxidative modification of LDL, as assessed by electrophoretic mobility, in a concentration dependent manner, but this effect was much more pronounced with HDL3. CONCLUSION: HDL3 may play an important role in the prevention of atherosclerosis in vivo, more effectively inhibiting oxidation of LDL than HDL2.

Antioxidants↗
PubMed1997

Histopathological study of a newly developed root canal sealer containing tetracalcium-dicalcium phosphates and 1.0% chondroitin sulfate.

We studied the possibility of the clinical use of a calcium phosphate-type newly developed sealer composed of tetracalcium phosphate, dicalcium phosphate dihydrate, and a modified McIlvain's buffer solution (TDM). Another sealer using the buffer solution, to which 2.5% chondroitin sulfate was added to promote wound healing (TDM-S), was also studied. TDM and TDM-S were histopathologically compared with another type of calcium phosphate sealer (ARS), which is commercially available in Japan, in the dorsal subcutaneous tissue and in the periapical tissue of rats. TDM and TDM-S caused no inflammatory reactions in the subcutaneous tissue. The periapical tissue reacted mildly to them. ARS caused severe inflammatory reactions in both the subcutaneous and the periapical tissue. These results indicate that TDM-S has excellent histocompatibility and potential as a root canal sealer.

Acrylic Resins↗
PubMed1997

Identification of casoxin C, an ileum-contracting peptide derived from bovine kappa-casein, as an agonist for C3a receptors.

Casoxin C (Tyr-Ile-Pro-Ile-Gln-Tyr-Val-Leu-Ser-Arg) is a bioactive peptide that was isolated from a tryptic digest of bovine kappa-casein as an anti-opioid peptide in longitudinal strips of guinea pig ileum. Casoxin C also evokes contraction of the ileal strips, and we found that this process was biphasic with rapid and slow components. The contractile profile was very similar to that of human complement C3a(70-77), which is the COOH-terminal octapeptide of C3a and has, although less potent, qualitatively the same biological activities as C3a. Casoxin C also has homology with C3a(70-77). The rapid contraction was mediated by histamine release and the slow contraction was mediated by a prostaglandin E2-like substance, judging from the effects of various pharmacological inhibitors and antagonists on the ileal contraction. Casoxin C had affinity for C3a receptors (IC50 = 40 microM) in the radioreceptor assay. In addition, casoxin C showed phagocyte-stimulating activities. Casoxin C is therefore the first milk-derived peptide identified, that acts through complement C3a receptors.

Amino Acid Sequence↗
PubMed1997

Continuous intraventricular drug infusion for the in vivo study of transneuronal degeneration in the striatonigral system of the rat.

Injuries to certain parts of the brain may induce neuronal death in distant areas innervated by the sites of the primary lesion. Such characteristic pathological changes, known as anterograde transneuronal degeneration, may occur at the next and more distant synaptic levels and play a part in the slow progression of some types of system degeneration. Delayed transneuronal degeneration of the substantia nigra pars reticulata (SNr) is one example of this form of cell death, and it occurs as a consequence of a neostriatal lesion caused by focal ischemia, Huntington's disease, or experimental axon-sparing injections of neurotoxin. Ever since the demonstration by Saji and Reis that the administration of GABA receptor agonist effectively prevented delayed transneuronal degeneration of the SNr, the degeneration of nigral reticulata cells has been attributed to the loss of striatal inhibition (Fig. 1A). The latter process severely upset the balance of membrane potential of nigral reticulata cells, producing an effect resembling excitotoxicity. In this report, we describe a continuous intraventricular MK-801 infusion technique that is useful in clarifying the role of glutamatergic action via N-methyl-D-aspartate (NMDA) receptor subclasses involved in exo-focal postischemic death of the SNr.

Animals↗
PubMed1997

Specific CYP3A4 inhibitors in grapefruit juice: furocoumarin dimers as components of drug interaction.

Four components were isolated from grapefruit juice that inhibit human CYP3A-mediated drug oxidation. The structures of these compounds were identified as furocoumarin derivatives by absorption spectra, APCI-liquid chromatography/tandem mass spectrometry and nuclear magnetic resonance after their purification by reversed-phase high performance liquid chromatography. They include two new furocoumarins, 4-[[6-hydroxy-7-[[1-[(1-hydroxy-1-methyl)ethyl]-4-methyl-6- (7-oxo-7H-furo[3,2-g][1]benzopyran-4-yl)-4-hexenyl]oxy]-3,7-dimeth yl- 2-octenyl] oxy]-7H-furo[3,2-g][1]benzopyran-7-one (GF-I-1) and 4-[[6-hydroxy-7-[[4-methyl-I- (1-methylethenyl)-6-(7-oxo-7H-furo[3,2-g][1]benzopyran-4-yl)-4- hexenyl] oxy]-3,7-dimethyl-2-octenyl]oxy]-7H-furo[3,2-g][1]benzopyran-7-one (GF-I-4). These furocoumarins are strong candidates for causative agents of grapefruit juice-mediated drug interaction, because of an inhibition potential that is equal to or stronger than the prototypical CYP3A4 inhibitor, ketoconazole, on liver microsomal testosterone 6 beta-hydroxylation.

Beverages↗
PubMed1997

Effects of glycyrrhizin on immune-mediated cytotoxicity.

Intravenous administration of glycyrrhizin is known to decrease elevated plasma transaminase levels in patients with chronic viral hepatitis, in which immune-mediated cytotoxicity by cytotoxic T lymphocytes and tumour necrosis factor (TNF)-alpha is considered to play an important pathogenic role. However, the immunological interpretation of the transaminase-lowering action of glycyrrhizin is not known. Studies were performed to elucidate this action immunologically by assessing the effects of glycyrrhizin on immune-mediated cytotoxicity using an antigen-specific murine CD4+ T hybridoma line, which exhibits cytotoxicity against antigen-presenting cells after stimulation with specific antigen, and a murine TNF-alpha-sensitive fibroblast line. Glycyrrhizin inhibited the cytotoxic activity of the T cells against antigen-presenting cells and also suppressed TNF-alpha-induced cytotoxicity in the TNF-alpha-sensitive cell line in vitro. These results suggest that the decrease of elevated transaminase levels by glycyrrhizin in patients with chronic viral hepatitis is mediated in part by inhibition of immune-mediated cytotoxicity against hepatocytes.

Animals↗
PubMed1997

The modified nucleoside 2-methylthio-N6-isopentenyladenosine in tRNA of Shigella flexneri is required for expression of virulence genes.

The virulence of the human pathogen Shigella flexneri is dependent on both chromosome- and large-virulence-plasmid-encoded genes. A kanamycin resistance cassette mutation in the miaA gene (miaA::Km Sma), which encodes the tRNA N6-isopentyladenosine (i6A37) synthetase and is involved in the first step of the synthesis of the modified nucleoside 2-methylthio-N6-isopentenyladenosine (ms2i6A), was transferred to the chromosome of S. flexneri 2a by phage P1 transduction. In the wild-type bacterium, ms2i6A37 is present in position 37 (next to and 3' of the anticodon) in a subset of tRNA species-reading codons starting with U (except tRNA(Ser) species SerI and SerV). The miaA::Km Sma mutant of S. flexneri accordingly lacked ms2i6A37 in its tRNA. In addition, the mutant strains showed reduced expression of the virulence-related genes ipaB, ipaC, ipaD, virG, and virF, accounting for sixfold-reduced contact hemolytic activity and a delayed response in the focus plaque assay. A cloned sequence resulting from PCR amplification of the wild-type Shigella chromosome and exhibiting 99% homology with the nucleotide sequence of the Escherichia coli miaA gene complemented the virulence-associated phenotypes as well as the level of the modified nucleoside ms2i6A in the tRNA of the miaA mutants. In the miaA mutant, the level of the virulence-associated protein VirF was reduced 10-fold compared with the wild type. However, the levels of virF mRNA were identical in the mutant and in the wild type. These findings suggest that a posttranscriptional mechanism influenced by the presence of the modified nucleoside ms2i6A in the tRNA is involved in the expression of the virF gene. The role of the miaA gene in the virulence of other Shigella species and in enteroinvasive E. coli was further generalized.

Alkyl and Aryl Transferases↗
PubMed1997

Percutaneous transluminal coronary angioplasty for morphologic left anterior descending artery lesion in a patient with dextrocardia. A case report and literature review.

A case report of percutaneous transluminal coronary angioplasty (PTCA) to treat coronary atherosclerotic lesions in a patient with dextrocardia associated with situs inversus totalis is presented. The patient was a sixty-two-year-old man who was admitted with a diagnosis of congestive heart failure. Cardiac catheterization was performed. Left ventriculography showed mild hypokinesis in segments 2 and 3 with ejection fraction of 63%. Coronary arteriography revealed 74% stenosis in segment 7 of the left anterior descending (LAD) artery. PTCA for this lesion was performed. Successful dilation was achieved with the residual stenosis in the LAD reduced from 74% to 34%. Performance of PTCA in patients with dextrocardia is extremely rare, and only 8 cases have been reported to date. However, by visualizing the procedure as a mirror image and choosing a guide catheter that permits good engagement, it appears possible to perform it like ordinary PTCA.

Angioplasty, Balloon, Coronary↗
PubMed1997

Studies on kochiae fructus. III. Antinociceptive and antiinflammatory effects of 70% ethanol extract and its component, momordin Ic from dried fruits of Kochia scoparia L.

The 70% ethanol extract (KS-ext) from Kochiae Fructus (dried fruits of Kochia scoparia L.) was screened for its activity on nociceptive and inflammatory responses in experimental animals. Although KS-ext at an oral administration of 500 mg/kg had an antinociceptive effect on writhing responses induced by acetic acid, it was ineffective on nociceptive response in the hot plate test. Oleanolic acid oligoglycoside, momordin Ic isolated from Kochiae Fructus significantly decreased the frequency of licking behavior within a unit of time at the late phase without affecting that of the early phase in the formalin test. Also, KS-ext inhibited the rise of vascular permeability induced by acetic acid, the increase of paw edema induced by carrageenin, histamine, serotonin or bradykinin and ear swelling induced by arachidonic acid. Momordin Ic also exhibited an inhibitory effect on carrageenin-induced edema. These results indicated that Kochiae Fructus has a peripheral antinociceptive effect mediated by antiinflammatory action, and that its active component can be partially attributed to momordin Ic.

Animals↗