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Biomedical subjects

T Akagi

Publications and source records attributed to T Akagi.

At least 37 records · Page 2Linked to original sources

Quantitative assessment of severity of ventricular septal defect by three-dimensional reconstruction of color Doppler-imaged vena contracta and flow convergence region.

BACKGROUND: The aim of the present study was to investigate the feasibility and potential value of the computer-controlled, 3D, echocardiographic reconstruction of the color Doppler-imaged vena contracta (CDVC) and the flow convergence (FC) region as a means of accurately and quantitatively estimating the severity of a ventricular septal defect (VSD). METHODS AND RESULTS: We performed a 3D reconstruction of the CDVC and the FC region in 19 patients with an isolated VSD using an ultrasound system interfaced with a Tomtec computer. The variable asymmetric geometry of the CDVC and the FC region could be 3D-visualized in all patients. The 3D-measured areas of CDVC correlated well with volumetric measurements of the severity of VSD (r=0.97, P:<0.001). Regression analysis between the shunt flow rate (calculated from the product of the area of CDVC and the continuous Doppler-derived velocity time integral) and the corresponding reference results (calculated by cardiac catheterization) demonstrated a close correlation (r=0.95, P:<0.001). There was also a good correlation between shunt flow rates calculated using the conventional 2D, 1-axis measurement of the FC isovelocity surface area with the hemispheric assumption (r=0.95, P:<0.001); shunt flow rates calculated using 3D, 3-axis measurements of the FC region (r=0.97, P:<0.01); and reference results by cardiac catheterization. However, the 2D method substantially underestimated the actual shunt flow rate. CONCLUSIONS: The 3D reconstruction of the CDVC and the FC region may aid in quantifying the severity of VSD.

Child↗

Multiple organ mucosa-associated lymphoid tissue lymphomas often involve the intestine.

BACKGROUND: Low grade mucosa-associated lymphoid tissue (MALT) lymphomas usually are confined to single extranodal organs. Although some case reports have been published, clinicopathologic characteristics of multiorgan MALT lymphomas remain unclear. METHODS: The authors evaluated 7 MALT lymphoma cases involving multiorgans in the past 7 years. In this period, they experienced 304 cases of MALT lymphomas. They analyzed the clinicopathologic features of these cases, including examination of clonal comparison among the lesions. RESULTS: The patients, 4 females and 3 males, were aged 55-68 years old (average, 60.1 years). Four cases showed multiple organ involvement at the initial diagnosis or after a short period. In the other three cases, primary foci were the stomach, thyroid gland, and ocular adnexa; after a rather long period (3 years or more), distant metastases were found. Although intestinal primary lymphomas are rather rare, six of the seven cases showed large intestinal involvement. Lymph node involvement was proven in only three cases. The patients were rather resistant to the various therapeutic approaches. Although six patients are alive, five are with disease. DNA analyses revealed that in five of the cases evaluated, identical clones were detected among the different affected organs. CONCLUSIONS: Multiorgan MALT lymphomas are rather rare. Most cases probably derived from a single clone, and lymphoma cells may selectively move among MALTs via a homing system with preferential involvement of the colon. Because multiorgan MALT lymphomas rarely achieve complete remission by treatment with combination chemotherapy or irradiation, MALT lymphomatous lesions should be checked carefully, especially in the large intestine.

Aged↗

Torn-off balloon tip of Z-5 atrial septostomy catheter.

Creation of atrial communication was performed in a newborn with critical aortic stenosis. After the success of the initial creation, balloon atrial septostomy using Z-5 catheter was performed. When catheter was pulled back, the tip of the balloon was torn off. This experience could be considered as noteworthy when using this catheter in patients with unusually thick atrial septum.

Angioplasty, Balloon, Coronary↗

Formation of filamentous tau aggregations in transgenic mice expressing V337M human tau.

Formation of neurofibrillary tangles (NFTs) is the most common feature in several neurodegenerative diseases, including Alzheimer's disease (AD). Here we report the formation of filamentous tau aggregations having a beta-sheet structure in transgenic mice expressing mutant human tau. These mice contain a tau gene with a mutation of the frontotemporal dementia parkinsonism (FTDP-17) type, in which valine is substituted with methionine residue 337. The aggregation of tau in these transgenic mice satisfies all histological criteria used to identify NFTs common to human neurodegenerative diseases. These mice, therefore, provide a preclinical model for the testing of therapeutic drugs for the treatment of neurodegenerative disorders that exhibit NFTs.

Animals↗

Reduction of hematopoietic cell-specific tyrosine phosphatase SHP-1 gene expression in natural killer cell lymphoma and various types of lymphomas/leukemias : combination analysis with cDNA expression array and tissue microarray.

To investigate the lymphomagenesis of NK/T lymphoma, we comprehensively and systematically analyzed the expression pattern of the human NK/T cell line (NK-YS) genome by cDNA expression array and tissue microarray. We detected significant changes in the gene expression of NK-YS cell line: an increase in 18 and a decrease in 20 genes compared to normal NK cells or peripheral blood mononuclear cells. Among these genes, we found a strong decrease in hematopoietic cell specific protein-tyrosine-phosphatase SH-PTP1 (SHP1) mRNA by cDNA expression array and reverse transcriptase-polymerase chain reaction. Further analysis with standard immunohistochemistry and tissue microarray, which used 207 paraffin-embedded specimens of various kinds of malignant lymphomas, showed that 100% of NK/T lymphoma specimens and more than 95% of various types of malignant lymphoma were negative for SHP1 protein expression. On the other hand, SHP1 protein was strongly expressed in the mantle zone and interfollicular zone lymphocytes in reactive lymphoid hyperplasia specimens. In addition, various kinds of hematopoietic cell lines, particularly the highly aggressive lymphoma/leukemia lines, lacked SHP1 expression in vitro, suggesting that loss of SHP1 expression may be related to not only malignant transformation, but also tumor cell aggressiveness. SHP1 expression could not be induced in either of two NK/T cell lines by phorbol ester, suggesting that genetic impairment or modification with methylation of SHP1 DNA could be one of the critical events in the pathogenesis of NK/T lymphoma. This evidence strongly suggests that loss of SHP1 gene expression plays an important role in multistep tumorigenesis, possibly as an anti-oncogene in the wide range of lymphomas/leukemias as well as NK/T lymphomas.

DNA, Complementary↗

An animal model for human EBV-associated hemophagocytic syndrome: herpesvirus papio frequently induces fatal lymphoproliferative disorders with hemophagocytic syndrome in rabbits.

Epstein-Barr virus-associated hemophagocytic syndrome (EBV-AHS) is often associated with fatal infectious mononucleosis. However, the animal model for EBV-AHS has not been developed. We reported the first animal model for EBV-AHS using rabbits infected with EBV-related herpesvirus of baboon (HVP). Eleven of 13 (85%) rabbits inoculated intravenously with HVP-producing cells developed fatal lymphoproliferative disorders (LPD) between 22 and 105 days after inoculation. LPD was also accompanied by hemophagocytic syndrome (HPS) in nine of these 11 rabbits. The peroral spray of cell-free HVP induced the virus infection with increased anti-EBV-viral capsid antigen-IgG titers in three of five rabbits, and two of these three infected rabbits died of LPD with HPS. Autopsy revealed hepatosplenomegaly and swollen lymph nodes. Atypical lymphoid T cells expressing EBV-encoded small RNA-1 infiltrated diffusely in many organs, frequently involving the lymph nodes, spleen, and liver. Hemophagocytic histiocytosis was observed in the lymph nodes, spleen, bone marrow, and thymus. HVP-DNA was detected in the tissues and peripheral blood from the infected rabbits by polymerase chain reaction or Southern blot analysis. Reverse transcriptase-polymerase chain reaction revealed both HVP-EBNA1 and HVP-EBNA2 transcripts, suggesting latency type III infection. These data indicate that the high rate of rabbit LPD with HPS induction is caused by HVP. This system is useful for studying the pathogenesis, prevention, and treatment of human EBV-AHS.

Animals↗

Clinical, histopathological, and immunogenetic analysis of ocular adnexal lymphoproliferative disorders: characterization of malt lymphoma and reactive lymphoid hyperplasia.

Malignant lymphomas and reactive lymphoid hyperplasia (RLH) in the ocular adnexa are sometimes difficult to differentiate morphologically and have often been categorized together as a lymphoproliferative disorder. Immunogenotypic characters of these diseases have not yet been well clarified. This study included 76 cases of ocular adnexal lymphoproliferative disorders. These consisted of 52 cases of malignant lymphoma (43 primary and 9 secondary), 22 of RLH, and 2 borderline cases. There were slightly more male than female subjects. Diagnoses were based on morphology and immunophenotypic characteristics. Clonalities were detected by means of polymerase chain reaction (PCR), and immunoglobulin heavy-chain variable region (VH) genes were sequenced in 10 cases of mucosa-associated lymphoid tissue (MALT) lymphoma. MALT lymphoma constituted 86% (37 cases) of the primary lymphomas. MALT lymphomas were more indolent, more rarely disseminated, and had a lower death rate than the other primary lymphomas. Two patients exhibited coexistence of MALT and diffuse large B-cell lymphoma. The average age of patients with RLH was 5.5 years younger than that of those with MALT lymphoma. One of the cases of RLH later progressed to malignant lymphoma. B-cell clonality was detected by PCR in 57%, 55%, and 0% of primary lymphomas, MALT lymphomas and RLHs, respectively. Sequencing of VH genes revealed that the VH3 family was the most commonly expressed germline VH family (70%) and that DP-63, DP-54 and DP-47 genes were frequently found in the MALT lymphomas examined. PCR analysis was useful for differentiation between MALT lymphoma and RLH. Sequence analysis of VH genes showed that an autoimmune mechanism may be involved in the lymphomagenesis of ocular adnexal MALT lymphoma.

Adult↗

Loss of expression of alpha4beta7 integrin and L-selectin is associated with high-grade progression of low-grade MALT lymphoma.

Expression of adhesion molecule in low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphoma of the gastrointestinal tract has been reported in recent years, but these reports have primarily focused on low-grade gastrointestinal MALT lymphoma. In this study, we examined the lymphocytic homing receptor alpha4beta7 integrin, L-selectin, and VLA-4 and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) in low-grade lymphoma of the gastrointestinal tract and other organs such as the ocular adnexa and thyroid. We also observed changes in the expression pattern associated with high-grade transformation. Neoplastic cells in the gastrointestinal low-grade lymphoma and the low-grade component of high-grade MALT lymphoma were found to be alpha4beta7 integrin(+), L-selectin(+), whereas the gastrointestinal high-grade component and diffuse large B-cell lymphoma were found to be alpha4beta7 integrin(-), L-selectin(-). High endothelial venules in the gastric MALT lymphomas expressed MAdCAM-1. In the ocular adnexa low-grade MALT lymphoma, most cases were alpha4beta7 integrin(-), L-selectin(+); and in the thyroid, most cases of both low- and high-grade MALT lymphoma were alpha4beta7 integrin(-), L-selectin(-). These findings show that alpha4beta7 integrin and L-selectin may play an important role in the lymphocyte homing of gastrointestinal low-grade MALT lymphoma and in the loss of alpha4beta7 integrin expression throughout the course of high-grade progression.

Cell Adhesion Molecules↗

Numerical, morphological and phenotypic changes in Langerhans cells in the course of murine graft-versus-host disease.

BACKGROUND: In the course of graft-versus-host disease (GVHD) or diseases that histologically mimic GVHD (e.g. toxic epidermal necrolysis, Stevens-Johnson syndrome), it is known that epidermal Langerhans cells (LCs) are depleted from the epidermis. However, the mechanism and significance of LC depletion is not well known. OBJECTIVES: To investigate the numerical, morphological and phenotypic changes in LCs and apoptosis of LCs in the course of GVHD using a non-irradiated mouse GVHD model. METHODS: BALB/c nu/nu mice and C57BL/6 mice were used as recipients and donors, respectively. Recipient mice were injected with T-cell-enriched donor spleen cells. Skin samples were harvested at various times after the inoculation. The numerical and morphological changes were examined by an immunofluorescence study of epidermal sheets. Apoptosis was studied by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling method and flow cytometric analysis using annexin V. Phenotypic change was studied by flow cytometric analysis of epidermal cell suspensions. The mixed epidermal cell lymphocyte reaction (MELR) was performed to examine functional changes in the epidermal cells. RESULTS: Five days after inoculation, a graft-versus-host reaction occurred. Epidermal LCs began to decrease from the sixth day. On the fifth day, the LCs became larger and had prominent dendrites. Immediately before the LCs began to decrease, many LCs became round in shape, with scanty dendrites. LC apoptosis was not observed in the epidermis either on the fifth or seventh day. Phenotypically, the expression of CD40, CD80, CD86 and major histocompatibility complex class II antigen on the LCs was upregulated on the fifth and seventh day. Epidermal cells from GVHD mice showed an increased allostimulatory capacity in the secondary MELR. CONCLUSIONS: These results suggest that at early GVHD onset, most LCs may not undergo apoptosis in the epidermis but are phenotypically activated, resulting in further activation of alloreactive T cells and aggravation of the disease.

Animals↗

Expression of costimulatory CD80/CD86-CD28/CD152 molecules in nasal mucosa of patients with perennial allergic rhinitis.

BACKGROUND: B7 molecules (CD80, CD86) and their counter-receptors, CD28 and CD152 (CTLA-4), play an important role in T cell-mediated immune responses. We previously demonstrated that B7 molecules are selectively up-regulated not only on B cells but also on T cells from the peripheral blood mononuclear cells of patients with perennial rhinitis cultured with allergen. However, the expression of CD80/CD86 molecules and their counter-receptors in nasal mucosa, the actual inflammatory site of allergic rhinitis, has not yet been clarified. PATIENTS AND METHODS: Inferior turbinates from patients with either allergy to house dust or non-allergic rhinitis were excised and immunohistologically stained. In addition, the inferior turbinates were challenged with paper discs containing extracts of house dust and subsequently excised. Samples were double stained with immunofluorescent-labelled antibody to identify cells bearing CD86. RESULTS: Without the nasal provocation, only the expression of CD86 was increased in nasal mucosa of patients with allergic rhinitis compared with those with non-allergic rhinitis. However, following the nasal provocation with house dust, not only CD86, but also CD80, CD28, and CD152 were significantly expressed in allergic patients. Immunofluorescent double staining revealed CD86 expression in CD19, CD1a, CD14 and CD3 lymphocytes. CONCLUSION: These results indicate that the expression of CD80/CD86 molecules and their counter-receptors is induced in allergic patients following nasal provocation with allergen, suggesting a local amplification of allergen-specific immune responses in perennial rhinitis.

Abatacept↗

Crk family adaptor proteins trans-activate c-Abl kinase.

BACKGROUND: c-Abl kinase is activated in response to a variety of biological stimuli. Crk family adaptor proteins can interact physically with c-Abl and be involved in the activation of c-Abl kinase. RESULTS: We report that the Crk family of adaptor proteins act as trans-acting activators of c-Abl kinase. The interaction of the amino-terminal Src-homology (SH) 3 domain of c-Crk and the proline-rich motifs of c-Abl is an essential step for the phosphorylation of c-Crk by c-Abl, as well as the activation of c-Abl by c-Crk. The activation of c-Abl by c-Crk is negatively regulated by phosphorylation of the tyrosine 221 of c-Crk. Our data suggest that, in the absence of phosphorylation of the tyrosine Y221, the SH2 domain of c-Crk becomes free to bind to target molecules while the carboxyl-terminal SH3 domain of c-Crk binds to the proline-rich region of c-Abl, inducing the activation of c-Abl by c-Crk. CONCLUSION: This study suggests that the Crk family functions as trans-acting activators of c-Abl kinase. The phosphorylation of c-Crk may regulate c-Abl kinase.

Animals↗

Ontogeny of the murine Ig joining chain gene and protein.

We used Northern blot analysis in order to investigate the ontogeny of the murine joining (J)-chain gene. No J-chain expression was detected in embryonic tissues, including liver, spleen and intestine, but an expression of mu heavy chain was detected in foetal liver at day 17. J-chain expression was detected in the spleen at day 9 and in the intestine at day 15 after birth. Western blot analysis was carried out in order to compare the protein levels of J and mu heavy chains in serum from day 8 to day 24 after birth, using antihuman J chain and antimouse mu chain antibodies. Although mu chain protein could be detected in serum from day 8, J-chain protein was detectable only at day 24. These results suggest that the expression of J chain is a later event than the mu chain in the mouse, which thus differs in embryogenesis from humans.

Animals↗

Re-treatment for immune globulin-resistant Kawasaki disease: a comparative study of additional immune globulin and steroid pulse therapy.

BACKGROUND: We compared the efficacy and safety of additional intravenous immune globulin (IVIG) therapy with steroid pulse therapy in patients with IVIG-resistant Kawasaki disease. METHODS: Two-hundred and sixty-two consecutive patients had been treated with a single dose of IVIG (2 g/kg) and aspirin (30 mg/kg per day). Thirty-five patients (13.4%) were not clinical responders to the initial IVIG treatment. They received an additional IVIG treatment (1 g/kg) within 48 h after the initial treatment. Seventeen patients (6.5%) did not respond to the additional IVIG treatment. We randomly divided these patients into two groups: group 1 consisted of eight patients who were treated with a single additional dose of IVIG (1 g/kg), while group 2 consisted of nine patients who were treated with steroid pulse therapy. RESULTS: The IVIG-resistant patients had a high incidence of coronary artery lesions (CAL; 48.6%). Five patients (62.5%) in group 1 had CAL, including two patients who each had a giant aneurysm and three patients who each had a small aneurysm. Seven patients (77.8%) in group 2 had CAL, including two patients who each had a giant aneurysm, two patients who each had a small coronary aneurysm and three patients who each showed transient dilatation during steroid pulse therapy. There was no significant difference in the incidence of CAL between the two groups. The duration of high fever in group 2 (1.4~0.7 days) was significantly shorter than in group 1 (4.8~3.4 days; P<0.05). The medical costs for the treatment of patients in group 2 (113, 012 yen +/- 22,084) were significantly lower than those for group 1 (144,194 yen +/- 12,914; P<0.05). CONCLUSIONS: Steroid pulse therapy may be useful in the treatment of patients with IVIG-resistant Kawasaki disease who experience prolonged fever. However, transient dilatation of the coronary artery is observed during steroid pulse therapy, so careful echocardiographic examination should be performed for those patients receiving steroid pulse therapy for the sake of early detection of coronary artery abnormalities.

Anti-Inflammatory Agents↗

Catheter closure of moderate to large sized patent ductus arteriosus using the simultaneous double or triple coil technique.

BACKGROUND: Although the clinical experience with transcatheter closure of the patent ductus arteriosus using the coils has grown rapidly, one important complication of this procedure using the conventional Gianturco coil was the migration of coils into peripheral vessels. This is especially for patients with a relatively larger size ductus and the risk for such complications could be increased. In this situation, the detachable coil may have some technical benefits to perform coil occlusion and reduce the incidence of complications. METHODS: We describe the clinical efficacy of a simultaneous double or triple coil occlusion technique using the Cook detachable coil or bioptome delivered 0.052 inch Gianturco coil to close the ductus arteriosus. This was performed in patients whose ductus diameter was greater than 3.0 mm. RESULTS: From February 1995 to December 2000, 118 patients with patent ductus arteriosus were treated by coil occlusion using Cook detachable coils, of whom 58 patients whose minimum diameter of ductus > or = 3.0 mm were reviewed. All patients had successful placement of coils. According to the evaluation by color flow mapping, a trivial shunt was observed in 17 patients (29%) within 24 h after the procedure. In 11 out of 17 patients, a residual shunt was not detected 1 month after the procedure. At 6 months after the procedure, the residual shunt was detected only in three patients. CONCLUSIONS: Although this study did not calculate the statistical significance between detachable and non-detachable coils in term of occlusion rate, our institutional experience suggests that the simultaneous double or triple coil technique using the detachable or 0.052 inch Gianturco coils can reduce the prevalence of coil migration or complications.

Adolescent↗

Guidelines for catheter intervention in coronary artery lesion in Kawasaki disease.

The Research Committee of Ministry of Health, Labour and Welfare 'Study of treatment and long-term management in Kawasaki disease' reported the guidelines for catheter intervention in coronary artery lesion in Kawasaki disease in this paper. The contents include: (i) background and natural history of coronary artery lesion in Kawasaki disease; (ii) indication of catheter intervention; (iii) types of procedure, and their indication and care; (iv) institute and backup system; (v) the management after procedure, evaluation and follow up; and (vi) prospects, especially in relation to bypass surgery.

Angioplasty, Balloon, Coronary↗

Simultaneous double or triple coil technique for closure of moderate sized (> or = 3.0 mm) patent ductus arteriosus.

One important complication of coil occlusion of patent ductus arteriosus using the conventional Gianturco coil is migration of coils into peripheral vessels. Especially in patients having relatively larger size ductus, the risk for such complication could be increased. In this regard, a detachable coil may have some technical benefits in performing coil occlusion and reducing the incidence of complications such as migration of coil. Based on our clinical experiences, we describe the clinical efficacy of a simultaneous double or triple coil occlusion technique using the Cook detachable coil system to close the ductus arteriosus, especially in patients whose ductus diameter more than 3.0 mm.

Adolescent↗

Differential subcellular localization of zinc in the rat retina.

In the retina, zinc is believed to be a modulator of synaptic transmission and a constituent of metalloenzymes. To determine whether the intracellular localization of zinc correlates with function, we examined the localization of endogenous zinc in the rat retina using the silver amplification method. By light microscopy, reaction products were detected in the pigment epithelial cells (PE), the inner segment of photoreceptors (IS), the outer nuclear layer (ONL) and the inner nuclear layer (INL), the outer plexiform layer (OPL) and the inner plexiform layer (IPL), and the ganglion cell layer (GC). The heaviest accumulation of precipitate was observed in PE and IS, whereas only a little precipitate was found in GC. When the intracellular zinc was chelated with diethyldithiocarbamate, a small amount of precipitate was observed only in ONL. By electron microscopy, zinc was associated with three compartments. In OPL and IPL, zinc was associated with neural processes, while in PE, IS, INL, and GC it was associated with the Golgi apparatus. In ONL, zinc was associated with the nucleus. Zinc in the neural processes is believed to act as a modulator of synaptic transmission, and zinc associated with the Golgi apparatus is assumed to catalyze metalloenzyme reactions.

Animals↗