[Aortic valve-sparing operation--determination of proper graft size and prevention of regurgitation ].
Explore the source record for details and available documents.
Aorta↗
Biomedical subjects
S Takagi
Publications and source records attributed to S Takagi.
Determination of Na channel blockers in paralytic shellfish toxins and pufferfish toxins with a tissue biosensor.
The biosensor consisted of a sodium electrode and covered with the frog bladder membrane within a flow cell was tested for the estimation of tetrodotoxin (TTX) and saxitoxin (STX). This sensor was applied to detect very low amounts of the Na+ channel blockers, STX and TTX, in different shellfishes and swellfishes. A good agreement was obtained between TTX activities determined by mouse assay and amounts of Na+ channel blockers estimated by frog membrane sensor. The lowest level of TTX (fg) that can be determined by frog membrane sensor does not cause human poisoning. The channel blockers in short-necked clam, which was assumed to be STX, were monitored by this sensor continuously every week for one year. It was discovered that the STX content increased from July until September and then decreased from October until March. The biosensor proposed here may be used for the estimation of STX and TTX conventionally in the future.
Animals↗
Usefulness of the medaka beta-actin promoter investigated using a mutant GFP reporter gene in transgenic medaka (Oryzias latipes).
The activity of the medaka beta-actin promoter as a ubiquitous expression vector in transgenic medaka was examined using complementary DNA of the green fluorescent protein (GFP). Plasmid pOBA-GFP contained both the medaka beta-actin promoter and cDNA of the wild-type GFP, while pOBA-hGFP contained the medaka beta-actin promoter and cDNA of the mutant GFP in which serine was substituted for threonine at position 65 and codon usage was humanized to promote translation in vertebrate cells. The ApaI-SmaI fragment of both plasmids was microinjected into the nuclei of oocytes or the cytoplasm of embryos at the one-cell stage. The gene expression was detected, using a fluorescent stereomicroscope, from early stages of development to 1 week after hatching. The expression of the wild-type GFP was detected in early embryos, in the yolk sac and in small portions of the muscle and epidermis. This expression pattern was similar to that of the Escherichia coli beta-galactosidase reporter gene (lacZ), driven by the medaka beta-actin promoter, which was examined in our previous studies. The mutant GFP was expressed in early embryos and in many tissues such as the epidermis, blood vessels, muscle, notochord, fin ray, gut, eyes, and yolk sac, and the fluorescence was much stronger than that of the wild-type GFP. Thus, the usefulness of the medaka beta-actin promoter as a ubiquitous expression vector was confirmed using the mutant GFP as a reporter gene.
Actins↗
[Transcatheter oily chemoembolization and intermittent hepatic artery infusion chemotherapy in the management of advanced hepatocellular carcinoma].
Between 1990 and 1997, 227 patients with hepatocellular carcinoma were treated by intrahepatic arterial injection of a Lipiodol-Epirubicin-Mitomycin C emulsion followed by intermittent hepatic artery infusion of Epirubicin, Mitomycin C and 5-FU, employing an implantable subcutaneous infusion port. A catheter was inserted percutaneously into the hepatic artery using the Seldinger technique. Objective remission was induced in 80% of the evaluable patients as evidenced by a decrease in their AFP and PIVKA II levels. These remissions were also confirmed by liver sonogram and CT scan showing decreased tumor volume. Transcatheter oily chemoembolization combined with intermittent hepatic artery infusion chemotherapy seems to be an effective treatment for unresectable hepatocellular carcinoma both for palliation of symptoms as well as prolongation of survival with good quality of life.
Antineoplastic Combined Chemotherapy Protocols↗
[Fulminant hepatic failure related to immunosuppressive therapy in an asymptomatic HBsAg carrier with idiopathic interstitial pneumonia].
A 72-year-old woman who was an asymptomatic HBsAg carrier was admitted because of productive cough and dyspnea on exertion. After close examination, she was given a diagnosis of idiopathic interstitial pneumonia (IIP), and treated with glucocorticoids and cyclophosphamide. However, fulminant hepatitis type B developed and the patient died of respiratory complications stemming from the acute exacerbation of IIP. To avoid such outcomes, extra caution should be taken when planning immunosuppressive therapy for HBsAg carriers.
Aged↗
Effects of azelastine on the level of serum interleukin-4 and soluble CD23 antigen in the treatment of nasal allergy.
Research findings and various published studies point to interleukin 4 (IL-4) and CD23 antigen as instrumental in allergic reactions of allergy patients because these two substances are part of the main triggering mechanisms in cells producing IgE antibodies. In this study it was investigated whether the control of IL-4 and CD23 levels result in a decrease of the severity of allergic reactions. It is well known that azelastine hydrochloride (AZ, CAS 79307-93-0) suppresses symptoms of nasal allergy. The antiallergic activity of this drug includes the suppression of IgE antibody production, antigen-antibody reactions, liberation of mediators and mediator antagonism. One report states that the cytokines IL-2, IL-3, and IL-4 were suppressed by AZ in cultured cells. There have been no reports regarding cytokines in clinical treatment using AZ. Therefore, the effects of AZ treatment on IL-4, soluble CD23, and RAST (radioallergosorbent test) levels in the sera of allergic rhinitis patients were studied. The results show that the levels of IL-4 and soluble CD23 were significantly reduced by the administration of AZ over a 4-week period, especially in patients with "excellent" or "good" efficacy of therapy.
Adult↗
[Ipsilateral central-type facial palsy and contralateral hemiparesis associated with unilateral medial medullary infarction: a case report].
Clinical pictures of medial medullary syndrome are variable, depending upon the extent of the lesion. Facial palsy has rarely been observed even in medullary infarction. However, central-type facial palsy is usually found contralaterally to the infarct area at the level of the rostral medulla. In the present report, we discuss the pathogenesis of the neurological manifestations in a 57-year-old man with hypertension. The patient presented with mild left facial palsy of central type, right hemiparesis, paresthesia, with deep sensory disturbance of the right extremities. An MRI of the brain showed an infarction localized in the medial region of the left upper medulla. Although the exact course of the supranuclear facial pathways remains controversial, the ipsilateral central facial palsy in this patient is considered to have two possible causes: the interruption of aberrant fibers of the corticobulbar tract, which branch off and swing back at the level of the upper-middle medulla, or the disruption of recurrent ascending fibers from the contralateral pyramidal tract, through decussation.
Cerebral Infarction↗
Identification and molecular characterization of fractalkine receptor CX3CR1, which mediates both leukocyte migration and adhesion.
Leukocyte trafficking at the endothelium requires both cellular adhesion molecules and chemotactic factors. Fractalkine, a novel transmembrane molecule with a CX3C-motif chemokine domain atop a mucin stalk, induces both adhesion and migration of leukocytes. Here we identify a seven-transmembrane high-affinity receptor for fractalkine and show that it mediates both the adhesive and migratory functions of fractalkine. The receptor, now termed CX3CR1, requires pertussis toxin-sensitive G protein signaling to induce migration but not to support adhesion, which also occurs without other adhesion molecules but requires the architecture of a chemokine domain atop the mucin stalk. Natural killer cells predominantly express CX3CR1 and respond to fractalkine in both migration and adhesion. Thus, fractalkine and CX3CR1 represent new types of leukocyte trafficking regulators, performing both adhesive and chemotactic functions.
Antigens, CD↗
Molecular cloning of a novel human CC chemokine secondary lymphoid-tissue chemokine that is a potent chemoattractant for lymphocytes and mapped to chromosome 9p13.
By searching the Expressed Sequence Tag (EST) data base, we identified partial cDNA sequences potentially encoding a novel human CC chemokine. We determined the entire cDNA sequence which encodes a highly basic polypeptide of 134 amino acids total with a putative signal peptide of 23 amino acids. The predicted mature protein of 111 amino acids has the four canonical cysteine residues and shows 21-33% identity to other human CC chemokines, but has a unique carboxyl-terminal extension of about 30 amino acids which contains two extra cysteine residues. The mRNA was expressed strongly in tissues such as the lymph nodes, Appendix, and spleen. The recombinant protein, which was produced by the baculovirus system and purified to homogeneity, was a highly efficient chemoattractant for certain human T cell lines and a highly potent one for freshly isolated peripheral blood lymphocytes and cultured normal T cells expanded by phytohemagglutinin and interleukin 2. Unlike most other CC chemokines, however, this novel chemokine was not chemotactic for monocytes or neutrophils, suggesting that it is specific for lymphocytes. From these results, we designated this novel CC chemokine as SLC from secondary lymphoid-tissue chemokine. SLC fused with the secreted form of alkaline phosphatase (SLC-SEAP) was used to characterize the SLC receptor. Binding of SLC-SEAP to freshly isolated lymphocytes was blocked by SLC (IC50, 0.12 nM) but not by any other CC chemokine so far tested, suggesting that resting lymphocytes express a class of receptors highly specific for SLC. By using somatic cell hybrids, radiation hybrids, and selected yeast and bacterial artificial chromosome clones, we mapped the SLC gene (SCYA21) at chromosome 9p13 and between chromosomal markers, D9S1978(WI-8765) and AFM326vd1, where the gene for another novel CC chemokine termed ELC from EBI1-ligand chemokine (SCYA19) also exists. Collectively, SLC is a novel CC chemokine specific for lymphocytes and, together with ELC, constitutes a new group of chemokines localized at chromosome 9p13.
Amino Acid Sequence↗
Identification of CCR6, the specific receptor for a novel lymphocyte-directed CC chemokine LARC.
Liver and activation-regulated chemokine (LARC) is a recently identified CC chemokine that is expressed mainly in the liver. LARC functions as a selective chemoattractant for lymphocytes that express a class of receptors specifically binding to LARC with high affinity. To identifiy the receptor for LARC, we examined LARC-induced calcium mobilization in cells stably expressing five CC chemokine receptors (CCR1-CCR5) and five orphan seven-transmembrane receptors. LARC specifically induced calcium flux in K562 cells as well as 293/EBNA-1 cells stably expressing an orphan receptor GPR-CY4. LARC induced migration in 293/EBNA-1 cells stably expressing GPR-CY4 with a bi-modal dose-response curve. LARC fused with secreted alkaline phosphatase (LARC-SEAP) bound specifically to Raji cells stably expressing GPR-CY4 with a Kd of 0.9 nM. Only LARC but not five other CC chemokines (MCP-1, RANTES, MIP-1alpha, MIP-1beta, and TARC) competed with LARC-SEAP for binding to GPR-CY4. By Northern blot analysis, GPR-CY4 mRNA was expressed mainly in spleen, lymph nodes, Appendix, and fetal liver among various human tissues. Among various leukocyte subsets, GPR-CY4 mRNA was detected in lymphocytes (CD4(+) and CD8(+) T cells and B cells) but not in natural killer cells, monocytes, or granulocytes. Expression of GPR-CY4 mRNA in CD4(+) and CD8(+) T cells was strongly up-regulated by IL-2. Taken together, GPR-CY4 is the specific receptor for LARC expressed selectively on lymphocytes, and LARC is a unique functional ligand for GPR-CY4. We propose GPR-CY4 to be designated as CCR6.
B-Lymphocytes↗
The T cell-directed CC chemokine TARC is a highly specific biological ligand for CC chemokine receptor 4.
Thymus and activation-regulated chemokine (TARC) is a recently identified CC chemokine that is expressed constitutively in thymus and transiently in stimulated peripheral blood mononuclear cells. TARC functions as a selective chemoattractant for T cells that express a class of receptors binding TARC with high affinity and specificity. To identify the receptor for TARC, we produced TARC as a fusion protein with secreted alkaline phosphatase (SEAP) and used it for specific binding. By stably transfecting five orphan receptors and five known CC chemokine receptors (CCR1 to -5) into K562 cells, we found that TARC-SEAP bound selectively to cells expressing CCR4. TARC-SEAP also bound to K562 cells stably expressing CCR4 with a high affinity (Kd = 0.5 nM). Only TARC and not five other CC chemokines (MCP-1 (monocyte chemoattractant protein-1), RANTES (regulated upon activation, normal T cells expressed and secreted), MIP-1alpha (macrophage inflammatory protein-1alpha), MIP-1beta, and LARC (liver and activation-regulated chemokine)) competed with TARC-SEAP for binding to CCR4. TARC but not RANTES or MIP-1alpha induced migration and calcium mobilization in 293/EBNA-1 cells stably expressing CCR4. K562 cells stably expressing CCR4 also responded to TARC in a calcium mobilization assay. Northern blot analysis revealed that CCR4 mRNA was expressed strongly in human T cell lines and peripheral blood T cells but not in B cells, natural killer cells, monocytes, or granulocytes. Taken together, TARC is a specific functional ligand for CCR4, and CCR4 is the specific receptor for TARC selectively expressed on T cells.
Alkaline Phosphatase↗
Effects of hydroxypropyl methylcellulose and other gelling agents on the handling properties of calcium phosphate cement.
The calcium phosphate cement (CPC) used in this study was formed by combining equimolar amounts of tetracalcium phosphate (TTCP) and dicalcium phosphate anhydrous (DCPA). This powder, when mixed with water, sets to a hard cement in about 30 min. However, the water-based CPC paste is not highly cohesive and is vulnerable to washout until hardening occurs. The objectives of this study were to investigate the effects on handling properties, washout resistance, cement hardening behavior, and mechanical properties of adding several gelling agents to CPC paste. Aqueous solutions that contained a mass fraction of 2-4% of hydroxypropyl methylcellulose (HPMC), carboxyl methylcellulose (CMC), chitosan acetate, and chitosan lactate were used as cement liquids. Hardening time was measured by the Gilmore needle test; resistance to washout was evaluated by the disintegration of the cement specimen in water with agitation; and mechanical strength was evaluated by the measurement of diametral tensile strength and compressive strength. Handling properties were greatly improved by the addition of HPMC, CMC, chitosan acetate, and chitosan lactate. Hardening time was retarded by the additions of HPMC and CMC, and mechanical strength was weakened by the addition of either the chitosan lactate or the chitosan acetate.
Biocompatible Materials↗
Clinical and prognostic significance of femoral marrow magnetic resonance imaging in patients with malignant lymphoma.
We evaluated 56 consecutive patients with newly diagnosed lymphoma including 48 with non-Hodgkin's lymphoma (NHL) and 8 with Hodgkin's disease to determine the clinical and prognostic significance of magnetic resonance imaging (MRI) of the femoral marrow. MR images of the femoral marrow were obtained by the T1-weighted spin echo method and the short TI inversion recovery technique. Abnormal "positive" images were seen in 29 of the 56 patients (52%). All 17 patients with positive biopsy results showed abnormal images on their femoral marrow MRI. Three "positive" MRI patterns-scattered (72%), uniform (21%), and nodular (7%)-were observed. The overall survival of the patients with a positive MRI pattern was significantly poorer than that of patients with a normal pattern (P = .0129). Survival did not differ significantly according to MRI pattern. The 3-year survival rate in the patients with a normal MRI pattern was 89.9% and in the patients with a positive MRI pattern, it was 41.0%. This difference was statistically significant (P = .0279) when we evaluated only the patients with NHL. Patients with positive MRI patterns, but a normal bone marrow histology, showed a significantly shorter survival than those with a normal MRI pattern (P = .016). These results indicate that abnormal MR images of the femoral marrow are associated with a significantly poorer survival in patients with malignant lymphoma, regardless of histologic findings in the marrow.
Adolescent↗
Roles of a neuronal cell-surface molecule, neuropilin, in nerve fiber fasciculation and guidance.
Neuropilin is a cell-surface glycoprotein that was first identified in Xenopus tadpole nervous tissues and then in chicken and mouse. The primary structure of neuropilin is highly conserved among these vertebrate species. The extracellular part of the molecule is composed of three domains referred to as a1/a2, b1/b2, and c, each of which is expected to be involved in molecular and/or cellular interactions. Neuropilin can mediate cell adhesion by heterophilic molecular interaction. In all vertebrate species examined, the neuropilin protein is restricted to axons of particular neuron classes, and at stages when axon growth is active. The gain and loss of function of neuropilin in developing mouse embryos causes defasciculation and incorrect sprouting of nerve fibers. These findings suggest that neuropilin serves in a variety of neuronal cell interactions by binding to a variety of molecules, and that it plays essential roles in nerve fiber fasciculation and guidance.
Animals↗
Characteristics of laryngeal receptors analyzed by presynaptic recording from the cat medulla oblongata.
In order to clarify the neural mechanisms for the protective laryngeal reflex, we conducted physiological analysis of laryngeal sensory receptors. In the present study, presynaptic unit activities, which might accurately reflect characteristics of the laryngeal receptor, were recorded with a glass microelectrode in the nucleus of the tractus solitarius of the medulla oblongata in ketamine-urethane anesthetized cats, and the responses to the mechanical and/or chemical stimuli were analyzed. From the results, it was demonstrated that highly sensitive mechanoreceptors and polymodal receptors exist in the laryngeal mucosa; they are particularly numerous in the laryngeal surface of the epiglottis and arytenoid region, and uncommon in the vocal fold. Mechanoreceptors on the laryngeal mucosa were classified into a rapidly adapting group and a slowly adapting group, while all polymodal receptors adapted rapidly to mechanical stimulation. These results suggest that these non-specific polymodal and rapidly adapting receptors may correspond to more superficial receptors such as free nerve endings and some taste buds, and also monomodal slowly adapting mechanoreceptors may correspond to deeper terminals in the subepithelium. It is also considered possible that the structures and the characteristics of these receptors are appropriate to elicit the protective laryngeal reflexes by non-specifically detecting various kinds of stimuli.
Animals↗
Magnetic resonance imaging of bone marrow in hematologic malignancies.
Magnetic resonance imaging (MRI) offers a global view of the bone marrow and facilitates the understanding of disease progression and the remission of hematologic malignancies. Marrow MRI is an important tool for accurate diagnosis, monitoring of disease extent, and evaluation of treatment response. MRI functions as an adjunct to bone marrow aspiration and biopsy. Furthermore, abnormal imaging on marrow MR may predict poor prognosis in patients with primary marrow disorders.
Bone Marrow↗
Extracellular components implicated in the stationary organization of the actin cytoskeleton in mesophyll cells of Vallisneria.
In mesophyll cells of Vallisneria gigantea Graebner, an aquatic angiosperm, the association of the plasma membrane with the cell wall at the end wall has been reported to be indispensable for the mechanism that maintains the stationary organization of the bundles of microfilaments (MFs) [Masuda et al. (1991) Protoplasma 162: 151]. To identify putative extracellular components that might play a crucial role in this mechanism, we examined the effects of two exogenously applied synthetic hexapeptides, GRGDSP and ARYDEI, which include an RGD and an RYD motif, respectively. The RGD motif is known as a recognition site in molecules required for adhesion to the substratum at sites of focal contacts. Within 24 h, both peptides (at concentrations of 1-15 mM) induced extremely abnormal patterns of cytoplasmic streaming, as well as the striking disruption of the arrangement of bundles of MFs. GRGESP and ARYEEI peptides, used as controls, had no detectable effects. Immunofluorescence microscopy revealed that polyclonal antibodies against the ARYDEI peptide bound to the cell walls of mesophyll cells while a preimmune serum did not. Western blotting analysis demonstrated that the antibodies recognized polypeptides of 54 kDa and 27 kDa in an extract of total proteins from the leaves of Vallisneria. The results suggest that some extracellular proteins(s), with a conserved RGD or RYD motif in its amino acid sequence, might be involved in the maintenance of the stationary organization of the bundles of MFs.
Actin Cytoskeleton↗
Effect of angiotensin II on arteriovenous shunting assessed by hepatic arterial perfusion scintigraphy.
Angiotensin II (AT II) has been reported to improve drug delivery in intraarterial chemotherapy for hepatic tumors. We studied the effect of this agent on arteriovenous (AV) shunting in the liver. Eleven patients with hepatic tumors and an indwelling catheter in the hepatic artery underwent hepatic arterial perfusion scintigraphy with and without AT II infusion. At baseline, following the administration of technetium-99m macroaggregated albumin (Tc-99m MAA) through the catheter, static images of the upper abdomen and whole-body anterior and posterior images were obtained. Two to 14 days later, AT II was infused via the catheter one minute prior to Tc-99m MAA injection, and imaging was performed in the same way as the baseline study. Visual interpretation of the static images showed improvement of drug delivery to the hepatic tumors in eight of 11 patients and no changes in the remaining patients. The percent injected dose in the lungs assessed quantitatively using the whole-body images increased in all patients, suggesting enhancement of AV shunt flow. It was concluded that intraarterial infusion of AT II increases AV shunting in the liver with better targeting to hepatic tumors.
Adult↗