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Biomedical subjects

T Kawakami

Publications and source records attributed to T Kawakami.

At least 235 records · Page 13Linked to original sources
PubMed1996

Development of a de novo tumorous necrotic lesion in the liver after transcatheter arterial embolization combined with iodized oil infusion: report of a case.

We report herein the case of a 69-year-old woman in whom a hepatic tumorous necrotic lesion was discovered following transcatheter arterial embolization combined with iodized oil infusion (Lp-TAE) for a hepatoma. The lesion, which had not been evident prior to the Lp-TAE, was resected and analyzed pathologically. The portal area distribution in the necrotic lesion was the same as that in the surrounding hepatic tissue, suggesting that the lesion was derived from the nonneoplastic hepatic tissue. Moreover, extensive wall thickening and obstruction were observed in the intrahepatic portal vein and hepatic artery. These findings suggest that the lesion was a focus of hepatic infarction triggered by Lp-TAE.

Aged↗
PubMed1996

Distribution of peptidergic nerve fibres in bullfrog lingual papillae demonstrated by a combination of double immunofluorescence labelling and a multiple dye filter.

Immunoreactivity of substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide, neuropeptide Y, and galanin is localized in nerve fibres distributed in the fungiform and filiform papillae of the tongue of the bullfrog, Rana catesbeiana. A combination of indirect double immunofluorescence labelling and a multiple dye filter system clearly demonstrated that all substance P fibres in the connective tissue core of the fungiform and filiform papillae, and within the rim of ciliated cells located on the top of the fungiform papillae showed coexistence with calcitonin gene-related peptide. A few fibres in the epithelial discs, which are located in the centre of the top of the fungiform papillae, showed the immunoreactivity of calcitonin gene-related peptide alone. There were no substance P fibres which showed coexistence with vasoactive intestinal polypeptide, galanin, and neuropeptide Y. In high magnification images, substance P and vasoactive intestinal polypeptide, and substance P and galanin fibres were recognized as two intertwined fibres within the same thin nerve bundle. No immunoreactivity of leucine- and methionine-enkephalins can be detected. These findings suggest that the chemoreceptor function of the bullfrog gustatory organ may be under the control of complicated peptidergic innervation.

Animals↗
PubMed1996

Signal transduction mechanism responsible for changes in axoplasmic transport caused by neurotransmitters.

Transduction mechanism for modulation of axoplasmic transport by neurotransmitters was studied using cultured mouse superior cervical ganglion cells. The transported particles were analyzed with a computer-assisted video-enhanced differential interference contrast microscope system. Acetylcholine depressed and adrenaline increased axoplasmic transport. GTP-binding proteins linked with both receptors activate or inactivate adenylyl cyclase, thereby altering the intracellular concentration of cyclic AMP. The cyclic AMP activates protein kinase A, which phosphorylates certain enzymes and the enzymes in turn phosphorylate motor proteins. An inhibitor protein kinase A, KT5720, decreases the number of the transported particles. In a stable state the cyclic AMP level stays at a normal level. Treatment with neurotransmitters causes a change in this level, which changes the activity of protein kinase A and thus decreases or enhances the phosphorylation of motor proteins. These changes are involved in the modulation of axoplasmic transport.

Acetylcholine↗
PubMed1996

Distribution of substance P and calcitonin gene-related peptide immunoreactive nerve fibers in the trachea of chronically hypoxic rats.

The distribution of substance P and calcitonin gene-related peptide immunoreactive nerve fibers in the trachea was compared between normoxic and chronically hypoxic rats (at 380 mm Hg for 10 weeks). In the normoxic trachea, the immunoreactivity to either peptide was seen in the nerve fibers in four principal locations: a) within and b) under the ciliated epithelium, c) within the smooth muscle bundles in the posterior wall, and d) in the connective tissue and around blood vessels in the lamina propria and submucosa. These immunoreactive fibers within the epithelium and smooth muscle bundles, in the connective tissue, and around blood vessels were thin and displayed some varicosities, and those under the epithelium appeared as thick nerve bundles. When the distribution and density of immunoreactive fibers were compared between normoxic and chronically hypoxic tracheas, there was a difference in number of substance P and calcitonin gene-related peptide immunoreactive fibers penetrating into the epithelium, although there was no difference in the other three locations. The mean number of substance P and calcitonin gene-related peptide immunoreactive intraepithelial fibers per section of the chronically hypoxic trachea was significantly increased. Because substance P and calcitonin gene-related peptide are predominant signal peptides of primary sensory neurons, the increase of substance P and calcitonin gene-related peptide immunoreactive fibers suggests that altered airway reflexes may be a feature of hypoxic adaptation.

Animals↗
PubMed1996

Tec family protein-tyrosine kinases and pleckstrin homology domains in mast cells.

Tec family protein-tyrosine kinases (PTKs) have been recognized as a distinct subfamily for only a few years. Two of them, Btk and Emt, are tyrosine-phosphorylated and enzymatically activated upon cross-linking of the high-affinity IgE receptor (Fc epsilonRI), suggesting their involvement in mast cell activation. Since Lyn and other Src family PTKs phosphorylate Btk at Tyr-551 and activate the latter kinase, the receptor-associated Lyn seems to activate Btk in mast cells. The Btk kinase activity, on the other hand, is regulated negatively by phosphorylation by protein kinase C (PKC) that is associated with Btk via Btk's pleckstrin homology (PH) domain. PH domains also bind to phospholipids and the beta subunit of heterotrimeric GTP-binding proteins. Therefore, it has been hypothesized that PH domains play roles in membrane localization.

Binding Sites↗
PubMed1996

Signal transduction through mu kappa B-cell receptors expressed on pre-B cells is different from that through B-cell receptors on mature B cells.

We introduced kappa light chain genes into pre-B cells to increase the surface mu HC expression, and established transfectants expressing mature type of B-cell receptors (BCR) on pre-B-cell surfaces. Since the cytoplasmic conformations of the reconstituted BCR and intrinsic pre-B-cell receptor (pre-BCR) are identical, they would be connected with the identical signal transduction pathways in pre-B cells. By using the transfectants, we revealed that the reconstituted BCR on pre-B cells was functionally equivalent to BCR on mature B cells in terms of the induction of intracellular Ca++ mobilization. However, we found that the signal-transduction pathways through BCR on pre-B cells were quantitatively different from those mature B cells in two ways. First, cross-linkage of the reconstituted BCR on pre-B cells induced preferential tyrosine phosphorylation of p120 and p100, which was not observed when BCR on mature B cells was cross-linked. Second, BCR in pre-B cells was physically associated with a larger amount of phosphatidylinositol-3 kinase (PI-3K) than BCR in mature B cells in spite of the fact that both pre-B and B cells expressed a similar amount of PI-3K in cytoplasm. Signals through pre-BCR and BCR are known to cause distinct biological effects in B-cell development. The biochemical features in the downstream of reconstituted BCR on pre-B cells, which we revealed in this study, will be of help in understanding the mechanism of functional differences between pre-BCR and BCR.

B-Lymphocytes↗
PubMed1996

A novel keratin K5 gene mutation in Dowling-Meara epidermolysis bullosa simplex.

We examined keratin K14 and K5 genes mutation in a Japanese Dowling-Meara epidermolysis bullosa simplex patient with severe generalized blistering and erosions at birth. The patient had a C to T transition at the first position of codon 174 in the keratin K5 gene, which resulted in a Leu->Phe substitution at the highly conserved 1A domain in keratin K5. Thus, our results revealed a novel mutation in the helix initiation peptide of keratin K5.

Amino Acid Sequence↗
PubMed1996

Anti-ribosomal P protein antibodies in a Japanese patient with systemic sclerosis.

A 56-year-old Japanese woman developed Raynaud's phenomenon and digital ulcerations at the age of 50. She showed rapid and diffuse skin sclerosis; visceral involvement was mild. She showed no symptoms or laboratory findings suggestive of other collagen diseases, including systemic lupus erythematosus and Sjögren's syndrome. Based on the clinical and histological findings, she was diagnosed as having diffuse cutaneous systemic sclerosis (SSc). The patient's serum produced nucleolar and cytoplasmic staining by indirect immunofluorescence analyses on HEp-2 cell substrate and reacted with P0, P1 and P2 proteins in immunoblotting using purified ribosomal antigens. She was negative for anti-topoisomerase I, centromere, and U1RNP antibodies. Antiribosomal P protein antibodies are considered highly specific for systemic lupus erythematosus; this is the first case report of an SSc patient with anti-ribosomal P protein antibodies. The clinical features of SSc patients with these antibodies need to be clarified by an accumulation of cases.

Autoantibodies↗
PubMed1996

An immunohistochemical analysis of implanted woven Dacron and expanded polytetrafluoroethylene grafts in humans.

An immunohistochemical analysis was performed to clarify the healing process in implanted vascular grafts in human. Eight woven Dacron grafts and 6 expanded polytetrafluoroethylene grafts were obtained following redo surgery, limb amputation, and autopsy. The implantation periods ranged from 5 days to 148 months. The antibodies used for the analysis were specific to alpha-actin (smooth muscle cells), macrophages, von Willebrand factor (endothelial cells), fibrin, elastin, collagen types 1-5, CD3 (T cells), and CD20 (B cells). At 5 and 24 days after implantation, thrombi containing red blood cells and fibrin covered the anastomotic lines and some of the luminal surfaces of the grafts. Macrophages were scattered throughout the thrombi. At 11-148 months after implantation, either a single layer of endothelial cells or a thin layer of fibrin covered the anastomotic segments of the grafts, and smooth muscle cells and collagen fiber were seen forming anastomotic intimal hyperplasia (AIH). The AIH in the grafts at 94 and 148 months after implantation was almost the same thickness and length a that in the grafts at 11-36 months after implantation Apart from the anastomotic segments, a connective tissue matrix containing collagen fibers covered the luminal surfaces, and some thrombi were noted. Most of the collagen present was type 3, in addition to some type 1, 4, and 5 collagen. No type 2 collagen was noted. Some elastin was also detected in the AIH but not in the midportion of the grafts. Some macrophages and T cells were noted in the perigraft tissues.

Actins↗
PubMed1996

Histological suture changes following retraction of the maxillary anterior bone segment after corticotomy.

By cephalometric and dental cast analyses, the effects of corticotomy in combination with 45-50 days retraction of the maxillary anterior segment were evaluated in five female Japanese monkeys (Macaca fuscata). In addition, microscopic changes of the related sutures were examined. According to the analyses of the dental casts, the retraction of the maxillary anterior segment in the experimental group was increased when compared with that of the control group. There was no change in occlusal molar relationship. The cephalometric analysis revealed that the "Point A" and "Metal Implant" on the mid-sagittal site between the upper central incisors in the experimental group showed more pronounced retraction than that in two untreated control animals. These results were histologically evaluated by changes of the suture structure: irregularity of functional arrangement of component cells and fibers, an increase in number of cells, resorption and formation of bone, and an enlargement of the suture width. Resorption of tooth roots and alveolar bone, and irregularity of the periodontal ligament were observed. In general, these histological changes appeared more extensive in the control specimens compared with the experimental specimens. The osseous histological changes were mainly observed in the compact bone area, while in the spongy bone area of both control and experimental specimens only minimal changes occurred. These results demonstrated the efficacy of combining a corticotomy procedure with retraction of the maxillary anterior bone segment by an orthodontic force.

Animals↗
PubMed1996

Isolation and mapping of a human gene (RPD3L1) that is homologous to RPD3, a transcription factor in Saccharomyces cerevisiae.

We have isolated a novel human gene RPD3L1, that is highly homologous to a transcription factor in Saccharomyces cerevisiae, RPD3 (reduced potassium dependency 3), from a human fetal lung cDNA library. The cDNA clone, hRPD3, consists of 2,100 nucleotides that contain an open reading frame of 1446 nucleotides encoding 482 amino acids. It shares 62% identity in nucleotide sequence and 52% identity in amino acid sequence to RPD3. This gene is expressed at various levels in all tissues examined. Furthermore, we were able to map it to chromosome band 1p34.1 by FISH.

3T3 Cells↗
PubMed1996

Spontaneous degranulation of cultured bone-marrow-derived immature mast cells from X-linked immunodeficient (Xid) mice.

IgE-mediated, antigen-dependent stimulation of immature mouse mast cells cultured in IL-3-containing media produces secretion by granule exocytosis. Similar cultured mast cells were derived from X-linked immunodeficient (Xid) mice and examined by electron microscopy. In these cultures, Xid mast cells were also immature. In contrast to cultures obtained from control mice, 10-20% of the immature mast cells of Xid origin were undergoing secretion by granule extrusion in the absence of any secretogogue. Spontaneous secretion may be related to discordered tyrosine kinase function and/or signal transduction pathways in the Xid mouse.

Animals↗
PubMed1996

Effects of aminobenzoic acid derivatives with 4-AET/HEMA in self-etching primer on bonding to ground dentin.

The effect of the inclusion of aminobenzoic acid derivatives (ABAD) in a self-etching primer comprising 4-acryloxyethyltrimellitic acid (4-AET), HEMA and water on shear bond strength to ground dentin was investigated. The mean bond strengths to dentin were significantly increased by the inclusion of 0.307 mol% ABAD in the 4-AET/HEMA primer, when compared with the control (0 wt% ABAD) (p < 0.01). A particularly high value (38.0 MPa) of shear bond strength was obtained in the use of the primer containing p-nitroanthranilic acid (p-NAA). It seemed to assume that the effect of p-NAA could be caused by the strong electron-withdrawing group of -NO2. From SEM observation, it was found that bonding resin appeared to adhere strongly to the ground dentin without formation of any resin-tags in the dentinal tubules. It was thought that the ABAD with 4-AET/HEMA could perform facilitating photo-polymerization at the bonding interface, and resulted in increased bond strength to ground dentin, and that the bond strength could be affected by the electronegativities of substitutional groups of ABAD.

4-Aminobenzoic Acid↗
PubMed1996

Effects of radical polymerizable spirocyclic monomers with new polymerization initiator systems on adhesion.

To develop a non-polymerization shrinkage adhesive resin, the effects of the contents varying 0-20 wt% radical polymerizable spirocyclic monomers of 2-methylene-1, 4, 6-trioxyaspiro [4, 6] undecane (MTSU) and 2-methylene-8, 9-benzo-1, 4, 6 trioxyaspiro [4, 4] nonane (BTSN) together with three kinds of initiator systems in adhesive resin on bonding to both Ni-Cr alloy and unetched enamel were investigated. Tensile bond strength to either Ni-Cr alloy or unetched enamel was affected by the inclusion of MTSU or BTSN, and indicated that increased contents of MTSU or BTSN resulted in decreased bond strength to the metal in the negative correlations. Regarding the bond strength to Ni-Cr alloy, however, the effective concentration of BTSN was found to be 5 wt%, and the mean bond strength was 58.5 and 58.6 MPa, respectively. The data of differential scanning calorimeter measurement, on the other hand, showed that the copolymerization of MTSU with conventional methacrylate monomers was not completely achieved.

Adhesiveness↗
PubMed1996

[Retrospective analysis on 21 patients with follicular lymphoma].

We retrospectively analyzed the clinical data of the 21 patients with follicular lymphoma admitted to our institution from 1977 to 1994. The frequency of follicular lymphoma was 9.1% in the 231 patients with non-Hodgkin's lymphoma. Overall survival rates at 1 year, 3 years, and 5 years were 90.2%, 78.2%, and 52.1%, respectively. The median follow-up of surviving patients and time to treatment failure (TTF) was 43 months and 30 months, respectively. The median time from disease progression to death was 171 days. In univariate analysis, factors associated with poor survival were stage IV (Ann Arbor staging system), anemia (hemoglobin level less than 10g/dl), bone marrow involvement, two or more extranodal sites, and failure in induction of complete remission (CR) in the entire course. Factors associated with short TTF were anemia, bone marrow involvement, and failure in induction of CR. In multivariate analysis, induction of CR affected survival and TTF independently.

Adult↗
PubMed1995

Activation and interaction with protein kinase C of a cytoplasmic tyrosine kinase, Itk/Tsk/Emt, on Fc epsilon RI cross-linking on mast cells.

Cross-linking of the high-affinity IgE receptor (Fc epsilon RI) on mast cells induces rapid phosphorylation on serine, threonine, and tyrosine residues and increases the enzymatic activity, of a Tec subfamily tyrosine kinase, Itk/Tsk/Emt (Emt). The pleckstrin homology domain of Emt at its amino-terminal interacts directly with multiple isoforms of protein kinase C (PKC) in vitro. In addition, a portion of Emt is physically associated with multiple isoforms of PKC in intact mast cells. PKC phosphorylates a bacterial fusion protein containing the pleckstrin homology domain of Emt in vitro. Coexpression of Emt in COS-7 cells with Ca(2+)-dependent PKC isoforms (alpha, beta I, or beta II) induces an enhancement in tyrosine phosphorylation of Emt. In vivo inhibition of PKC expression or activity attenuates tyrosine phosphorylation and enzymatic activity of Emt induced upon Fc epsilon RI cross-linking. These data collectively suggest that PKC phosphorylates Emt and activates its autophosphorylating activity. Alternatively, PKC could activate another tyrosine kinase that phosphorylates Emt, or PKC-mediated phosphorylation of Emt may render it a target for another tyrosine kinase. In any case, PKC appears to play a major role in the activation of Emt induced upon Fc epsilon RI cross-linking.

Animals↗