Biomedical subjects

T Yamane

Publications and source records attributed to T Yamane.

At least 91 records · Page 5Linked to original sources

PubMed2001

[Two cases of bronchus-associated lymphoid tissue lymphoma].

We report 2 cases of bronchus-associated lymphoid tissue lymphoma (BALT lymphoma), which is a rare disease. Patient 1 was a 76-year-old woman with a chief complaint of cough. Since plain chest radiography revealed an abnormal shadow in the hilum of the lung, she visited our hospital. Patient 2 was a 56-year-old man, who had been diagnosed as having pseudolymphoma at a medical check-up in a local hospital. During follow-up, however, he was referred to our hospital because of enlarged tumors and chest pain. In both patients, bronchofiberscopy demonstrated submucosal tumors and biopsy samples showed formation of lymphoepithelial lesions by centrocyte-like cells with a B-cell staining pattern. The patients were therefore diagnosed as having BALT lymphoma. Both received CEOP-E treatment, which improved the clinical symptoms but did not result in complete remission. The patients have been followed up after discontinuation of the medication. The progress of the disease has been slow, and both patients are alive as of September 2001.

Aged↗

PubMed2000

Efficacy and safety of an irrigated-tip catheter for the ablation of accessory pathways resistant to conventional radiofrequency ablation.

BACKGROUND: Radiofrequency catheter ablation of accessory pathways (APs) is very effective in all but a minority of patients. We examined the usefulness and safety of irrigated-tip catheters in treating patients with APs resistant to conventional catheter ablation. METHODS AND RESULTS: Among 314 APs in 301 consecutive patients, conventional ablation failed to eliminate AP conduction in 18 APs in 18 patients (5.7%), 6 of which were located in the left free wall, 5 in the middle/posterior-septal space, and 7 inside the coronary sinus (CS) or its tributaries. Irrigated-tip catheter ablation was subsequently performed with temperature control mode (target temperature, 50 degrees C), a moderate saline flow rate (17 mL/min), and a power limit of 50 W (outside CS) or 20 to 30 W (inside CS) at previously resistant sites. Seventeen of the 18 resistant APs (94%) were successfully ablated with a median of 3 applications using irrigated-tip catheters. A significant increase in power delivery was achieved (20.3+/-11.5 versus 36.5+/-8.2 W; P:<0.01) with irrigated-tip catheters, irrespective of the AP location, particularly inside the CS or its tributaries. No serious complications occurred. CONCLUSIONS: Irrigated-tip catheter ablation is safe and effective in eliminating AP conduction resistant to conventional catheters, irrespective of the location.

Adult↗

PubMed2000

Electrophysiological breakthroughs from the left atrium to the pulmonary veins.

BACKGROUND: The extent of ostial ablation necessary to electrically disconnect the pulmonary vein (PV) myocardial extensions that initiate atrial fibrillation from the left atrium has not been determined. METHODS AND RESULTS: Seventy patients underwent PV mapping with a circumferential 10-electrode catheter during sinus rhythm or left atrial pacing. After assessment of perimetric distribution and activation sequence of PV potentials, ostial ablation was performed at segments showing earliest activation, with the end point of PV disconnection. A total of 162 PVs (excluding right inferior PVs) were ablated. PV potentials were present at 60% to 88% of their perimeter, but PV muscle activation was always sequential from a segment with earliest activation (breakthrough). Radiofrequency (RF) application at this breakthrough eliminated all PV potentials in 34 PVs, whereas a secondary breakthrough required RF applications at separate segments in 77; in others, >2 segments were ablated. A median of 5, 6, and 4 bipoles from the circular catheter were targeted in the right superior, left superior, and inferior PVs, respectively, to achieve PV disconnection. Early recurrence of arrhythmia was observed in 31 patients as a result of new venous or atrial foci or recovery of previously targeted PVs, most related to a single recovered breakthrough that was reablated with local RF application. CONCLUSIONS: Although PV muscle covers a large extent of the PV perimeter, there are specific breakthroughs from the left atrium that allow ostial PV disconnection by use of partial perimetric ablation.

Angiography↗

PubMed2000

Mapping-guided ablation of pulmonary veins to cure atrial fibrillation.

Catheter ablation of triggers inducing paroxysms of atrial fibrillation (AF) is an emerging therapy for this common arrhythmia. In a series of 225 consecutive patients with AF resistant to multiple drugs, 96% presented with triggering foci originating from 1 or multiple pulmonary veins (PV), independently of whether or not the patient had ectopy or structural heart disease. The present article describes the mapping and ablation techniques applicable to individual patients: (1) criteria to define an arrhythmogenic PV; (2) use of provocative maneuvers; and (3) the role of circumferential mapping catheters to provide extent, distribution, and activation of PV muscle as well as monitoring distal PV potentials (PVP) during ablation. Radiofrequency ablation can be performed by targeting the PVP during sinus rhythm (right PV) or left atrial pacing (left PV) with the procedural endpoint of PVP elimination, which is more effective in predicting a successful outcome than suppression of acute ectopy. Complete elimination of AF is presently obtained in 70% of patients, allowing interruption of arrhythmias and in use anticoagulants. It is anticipated that continued technologic improvements will improve and facilitate this technique of curative treatment of AF.

Atrial Fibrillation↗

PubMed2000

Alteration of rat dipeptidyl peptidase III by site-directed mutagenesis: cysteine(176) is a regulatory residue for the enzyme activity.

To comprehend the importance of cysteine residues for the regulation of enzyme activity, we replaced each of seven cysteine residues in rat dipeptidyl peptidase III cDNA with alanine, glycine, or glutamic acid residue using site-directed mutagenesis. Each mutated cDNA was expressed in E. coli (BL21), and each expressed DPP III was purified to apparent homogeneity on SDS-polyacrylamide gel electrophoresis. Six of the mutant proteins had similar activity to that of the wild-type enzyme, whereas the activity of the Cys(176) --> Ala mutant enzyme was only 25-35% of that of the wild-type enzyme activity. This mutant enzyme was resistant against both PCMB and NEM. Furthermore, both Cys(176) --> Gly and Cys(176) --> Glu mutated enzymes showed no DPP III activity. These seven mutated enzymes contained significant amounts of zinc, as determined by atomic absorption spectrometry. The results indicate that Cys(176) is essential for the regulation of DPP III activity.

Amino Acid Substitution↗

PubMed2000

Molecular cloning and immunohistochemical localization of rat dipeptidyl peptidase III.

Dipeptidyl peptidase III (DPP III) was purified to homogeneity from rat liver cytosol. The calculated molecular weight of the purified enzyme was 82845.6 according to TOF-MS, and 82000 on non-denatured PAGE and 82000 on SDS-PAGE in the absence or presence of beta-ME. These findings suggest that the enzyme assumes a monomeric form in rat liver cytosol. The enzyme rapidly hydrolyzed the substrate Arg-Arg-MCA and moderately hydrolyzed Ala-Arg-MCA in a pH range of 7. 5 to 9.5. The K(in), K(cat) and K(cat)/K(m) values of DPP III at optimal pH (pH 8.5) were 290 microM, 18.0 s(-1) and 6.21x10(4) s(-1)M(-1) for Arg-Arg-MCA and 125 microM, 4.53 s(-1) and 3.62x10(4) s(-1)M(-1) for Ala-Arg-MCA, respectively. DPP III was potently inhibited by EDTA, 1,10-phenanthroline, DFP, PCMBS, NEM, beta-ME and iodoacetamide. Furthermore, we screened a rat liver cDNA library using affinity-purified anti-rat DPP III rabbit IgG, and we determined the cDNA structure and deduced the amino acid sequence. The cDNA designated as lambdaRDIII-11 is composed of 2640 bp of nucleotides in length and encodes 738 amino acids in the coding region. Although the enzyme has a novel zinc-binding motif, HEXXXH in structure, DPP III is thought to belong to family 1 in clan MA in the metalloprotease kingdom. These findings suggest that DPP III is a metalloprotease that is probably regulated by SH modification. The DPP III antigen was extensively detected in the cytosol of various rat tissues by the immunohistochemical examination of the protein.

Amino Acid Sequence↗

PubMed2000

Intramedullary and extramedullary B lymphopoiesis in osteopetrotic mice.

Adult bone marrow is a major site for hematopoiesis, and reduction of the bone marrow cavity induces hematopoiesis in extramarrow tissues. To investigate the rudimentary intramarrow and the compensatory extramarrow hematopoiesis, particularly B lymphopoiesis, we used 3 osteopetrotic mouse strains [op/op, mi/mi, and Fos (-/-)], which are severely deficient in functional osteoclasts and therefore form inadequate bone marrow cavities. We found that bone marrow in these osteopetrotic mice supports myelopoiesis but not B lymphopoiesis, although cells that have the potential to differentiate into B lineage cells are present in the bone marrow. Although B lymphopoiesis normally occurs both in the spleen and liver of newborn mice, compensatory B lymphopoiesis in adult op/op and mi/mi mice is observed only in the liver, while myelopoiesis is enhanced in both organs. Interestingly, mice lacking the Fos proto-oncogene exhibit B lymphopoiesis in the spleen as well as liver. The amounts of expression of steel factor, Flt3/Flk-2 ligand, and interleukin-7 in the bone marrow, spleen, or liver were not significantly affected in these osteopetrotic mutants. These findings suggest that the volume of the bone marrow cavity regulates B lymphopoiesis without affecting the production of certain hematopoietic growth factors. The splenic microenvironments that support both myelopoiesis and B lymphopoiesis in the neonatal stage are lost in adults and are not reactivated even in the osteopetrotic adults unless the Fos gene is disrupted.

Aging↗

PubMed2000

Molecular and immunochemical evidences demonstrate that endooligopeptidase A is the predominant cytosolic oligopeptidase of rabbit brain.

Oligopeptidases are tissue endopeptidases that do not attack proteins and are likely to be involved in the maturation and degradation of peptide hormones and neuropeptides. The rabbit brain endooligopeptidase A and the rat testes soluble metallopeptidase (EC 3.4.24.15) are thiol-activated oligopeptidases which are able to generate enkephalin from a number of opioid peptides and to inactivate bradykinin and neurotensin by hydrolyzing the same peptide bonds. A monospecific antibody raised against the purified rabbit brain endooligopeptidase A allowed the identification of a 2. 3 kb cDNA coding for a truncated enzyme of 512 amino acids, displaying the same enzymatic features as endooligopeptidase A. In spite of all efforts, employing several strategies, the full-length cDNA could not be cloned until now. The analysis of the deduced amino acid sequence showed no similarity to the rat testes metalloendopeptidase sequence, except for the presence of the typical metalloprotease consensus sequence [HEXXH]. The antibody raised against recombinant endooligopeptidase A specifically inhibited its own activity and reduced the thiol-activated oligopeptidase activity of rabbit brain cytosol to less than 30%. Analysis of the endooligopeptidase A tissue distribution indicated that this enzyme is mainly expressed in the CNS, whereas the soluble metallo EC 3.4.24.15 is mainly expressed in peripheral tissues.

Amino Acid Sequence↗

PubMed2000

Argatroban as an anticoagulant for both hematologic and chemical tests.

Argatroban possesses strong antithrombin-like activity. We evaluated the usefulness of argatroban in anticoagulating specimens for routine laboratory tests. Results using blood anticoagulated with argatroban corresponded well with the results of blood treated with ethylendiamine tetra-acetic acid (EDTA) in the complete blood count (CBC), including the WBC differential count and morphology of blood cells, when the CBC was performed within 2 hr of blood collection. Clinical chemistry results from argatroban-treated samples were similar to results obtained with serum specimens. Thus, argatroban may be a useful anticoagulant for emergency laboratory medicine.

Anticoagulants↗

PubMed2000

Synthetic polymer sulphonated polyisoprene as a universal anticoagulant for laboratory testing.

To evaluate the feasibility of a synthetic polymer, sulphonated polyisoprene (SPIP), to be used as a new laboratory anticoagulant, hematological items were compared between blood samples anticoagulated with EDTA and SPIP, as were biochemical and electrolyte items between serum samples and SPIP-anticoagulated blood. Among hematological items, the average platelet count of the SPIP group was significantly lower than that of the EDTA group, due to platelet aggregation in the SPIP group. Addition of kanamycin to SPIP, but not of aspirin or prostaglandin E1, restored platelet count to about 80% of that in the EDTA group, and increased coefficients of correlation with the EDTA group for most hematological items examined. For biochemical and electrolyte items, high (> 0.95) correlation coefficients were obtained for 15 of 18 items between the serum and SPIP-anticoagulated samples. However, for some of these items, the addition of kanamycin decreased coefficients of correlation. Thus, SPIPs are excellent candidates for new anticoagulants that can be used for evaluation of hematological, biochemical, and electrolyte items with a single test tube in routine laboratory work. However, some improvements are required for use of kanamycin as an additive to inhibit platelet aggregation induced by SPIP, and in maintaining reliability of biochemical and electrolyte measurements.

Adult↗

PubMed2000

New enzymatic method for determining D-arabinitol in serum.

A new reagent has been developed to determine D-arabinitol. This utilizes D-arabinitol 2-oxidoreductase derived from Bacillus sp. with high stability, and water-soluble tetrazolium salt, that can detect NADH with high sensitivity. Since this enzyme does not react to D-mannitol, elimination of D-mannitol is unnecessary. Thus, this is a much simpler process than currently available with commercial kits use D-arabinitol 4-oxidoreductase. The within-run and between-run precisions (CV) were 2.4-6.9% and 3.1-8.7%, respectively, whilst the correlation (r) between the results obtained with our proposed method (y) and those obtained with the commercial "Arabinitec-auto" kit (x) was 0.964 (y = 1.02x + 0.933 mumol/l; n = 69). However, some samples deviated remarkably from correlation in both methods. Our analyzing accuracy is satisfactory in clinical application, as it does not miss positive sample over cut-off value. We are refining this method by investigating why some specimens are apart from correlation significantly.

Biomarkers↗

PubMed2000

Clinical evaluation of 99mTc-Technegas SPECT in thoracoscopic lung volume reduction surgery in patients with pulmonary emphysema.

UNLABELLED: 99mTc-Technegas (Tcgas) SPECT is useful for evaluating the patency of the airway and highly sensitive in detecting regional pulmonary function in pulmonary emphysema. The aim of this study is to evaluate regional ventilation impairment by this method pre and post thoracoscopic lung volume reduction surgery (LVRS) in patients with pulmonary emphysema. METHODS: There were 11 patients with pulmonary emphysema. The mean age of patients was 64.1 years. All patients were males. LVRS was performed bilaterally in 8 patients and unilaterally in 3 patients. Post inhalation of Tcgas in the sitting position, the subjects were placed in the supine position and SPECT was performed. Distribution of Tcgas on axial images was classified into 4 types, A: homogeneous, B: inhomogeneous, C: hot spot, D: defect. Three slices of axial SPECT images, the upper, middle and lower fields were selected, and changes in deposition patterns post LVRS were scored (Tcgas score). RESULTS: Post LVRS, dyspnea on exertion and pulmonary function tests were improved. Pre LVRS, inhomogeneous distribution, hot spots and defects were observed in all patients. Post LVRS, improvement in distribution was obtained not only in the surgical field and other fields, but also in the contralateral lung of unilaterally operated patients. In 5 patients some fields showed deterioration. The Tcgas score correlated with improvements in FEV1.0, FEV1.0% and %FEV1.0. CONCLUSION: Tcgas SPECT is useful for evaluating changes in regional pulmonary function post LVRS.

Aged↗

PubMed2000

Large Bielschowsky head-tilt phenomenon and inconspicuous vertical deviation in the diagnostic positions in congenital superior oblique palsy.

PURPOSE: To report a case of congenital superior oblique palsy with an unusually large Bielschowsky head-tilt phenomenon (BHP) and disproportional inconspicuous vertical deviation. METHODS: Case report. RESULTS: An 18-year-old woman presented with slight compensatory head tilting and a Bielschowsky head-tilt phenomenon of 50 Delta on left tilting. Magnetic resonance imaging revealed atrophy of the left superior oblique muscle. A Hess screen test showed a slight underaction of the left superior oblique muscle, but neither an obvious overaction of the ipsilateral inferior oblique muscle nor inhibitory palsy of the contralateral superior rectus muscle was found. With a 3-mm recession of the ipsilateral superior rectus muscle, Bielschowsky head-tilt phenomenon decreased to 25 Delta. CONCLUSION: A large Bielschowsky head-tilt phenomenon was possibly caused by an increased gain of the otolith-ocular reflex affecting the vertical rectus muscle.

Adolescent↗

PubMed2000

DX-9065a, a specific factor Xa inhibitor, as a universal anticoagulant for blood collection tubes.

DX-9065a is a direct and selective factor Xa inhibitor. We evaluated the usefulness of DX-9065a in anticoagulating specimens for routine laboratory tests. Results using blood anticoagulated with DX9065a corresponded well with results with blood treated with ethylendiamine tetraacetic acid (EDTA) in the complete blood count (CBC), including white blood cell (WBC) differential count and morphology of blood cells. Clinical chemistry results from DX-9065a-treated samples were similar to results obtained with serum specimens except for leucine aminopeptidase (LAP) and cholinesterase (Ch-E). Thus, DX-9065a may be a useful universal anticoagulant for laboratory medicine.

Anticoagulants↗

PubMed2000

Sequential requirements for SCL/tal-1, GATA-2, macrophage colony-stimulating factor, and osteoclast differentiation factor/osteoprotegerin ligand in osteoclast development.

OBJECTIVE: Osteoclasts are of hematopoietic origin. The mechanism by which hematopoietic stem cells are specified to the osteoclast lineage is unclear. To understand the process of generation and differentiation of this lineage of cells, we performed in vitro studies on the differentiation of embryonic stem cells. MATERIALS AND METHODS: We examined the potential of mutant embryonic stem cell lines harboring targeted deletions of the GATA-1, FOG, SCL/tal-1, or GATA-2 genes to differentiate into osteoclasts and determined when these molecules function in osteoclast development. RESULTS: The lack of GATA-1 or FOG did not affect osteoclastogenesis. In contrast, SCL/tal-1-null embryonic stem cells generated no osteoclasts. In the case of the loss of GATA-2, a small number of osteoclasts were generated. GATA-2-null osteoclasts were morphologically normal and the terminal maturation was not disturbed, but a defect was observed in the generation of osteoclast progenitors. Experiments using specific inhibitors that block the signaling through macrophage colony-stimulating factor and osteoclast differentiation factor/osteoprotegerin ligand suggested that GATA-2 seems to act earlier in osteoclastogenesis than these cytokines. Interestingly, macrophage colony-forming units were not severely reduced by the loss of GATA-2 compared to osteoclast progenitors. CONCLUSION: These results indicate that osteocalsts need SCL/tal-1 at an early point in development, and that GATA-2 is required for generation of osteoclast progenitors but not for the later stages when macrophage colony-stimulating factor and osteoclast differentiation factor/ osteoprotegerin ligand are needed. We also demonstrated that osteoclast progenitors behave as a different population than macrophage colony-forming units.

Basic Helix-Loop-Helix Proteins↗

PubMed2000

Importance of disulfide bridge formation on folding of phospholipase D from Streptomyces antibioticus.

The effects of redox conditions on the folding of phospholipase D (PLD) of Streptomyces antibioticus were investigated. Although the enzyme was very stable even in the presence of 1.0 M guanidinehydrochloride (Gdn-HCl), the coexistence of dithiothreitol (DTT) and Gdn-HCl inactivated the enzyme completely. The inactivated enzyme recovered its activity by dialysis in which DTT was removed prior to Gdn-HCl, whereas its activity was not recovered when Gdn-HCl was removed prior to DTT. In vitro protein synthesis was used for further analyses of the folding process. Active PLD was synthesized in the absence of DTT. The activity increased as the protein synthesis proceeded. In contrast, inactive PLD was synthesized in the presence of DTT. The inactive PLD could not be effectively activated by simple removal of the reductant, while incubation with Gdn-HCl and subsequent removal of DTT followed by that of Gdn-HCl was a much more effective method for the synthesis of active enzymes. From these results, it is suggested that: (i) PLD contains disulfide bridge(s), which is (are) necessary for maintaining its tertiary structure, (ii) correct formation of the disulfide bridge(s) is a critical step in the early stage of the (re)folding process, and (iii) the disulfide bridge(s) further facilitate the folding process, resulting in the synthesis of the active enzymes with the correct structure.

Journal Article↗

PubMed2000

Transmission of symptomatic parvovirus B19 infection by fibrin sealant used during surgery.

Human parvovirus B19 infection has been shown to be transmissible by blood and blood products and to result in transient aplastic crisis in patients with rapid red cell turnover. We report three cases of iatrogenic parvovirus B19 infection resulting from the use of the same batch of fibrin sealant under operation. Fibrin sealant, which is a typical haemostatic agent produced from blood, has been used during surgery. Human parvovirus is resistant to existing virus-inactivating techniques, suggesting that infection may occur from blood products contaminated with it. Use of recombinant products for these proteins may thus be necessary.

Adult↗

PubMed2000

Ex vivo expansion of mature human neutrophils with normal functions from purified peripheral blood CD34+ haematopoietic progenitor cells.

Purified CD34+ haematopoietic progenitor cells were cultivated with stem cell factor, interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte CSF (G-CSF) for 7 d, and thereafter non-adherent cells were divided into two groups. Cells in one group (group A) were further cultivated for 7 d with four cytokines, and cells in the other group (group B) were further cultivated for 7 d with G-CSF alone. On day 14, 220-fold and 130-fold increases in the numbers of non-adherent cells were achieved for groups A and B respectively. These cell preparations contained 65% granulocytes for group A and 95% granulocytes for group B. These cells gained the ability to respond effectively with chemotaxis, phagocytosis and superoxide (O2-) release. Cells in group B were appropriately primed by G-CSF, GM-CSF, tumour necrosis factor alpha and IL-1beta for enhanced release of O2 -. The responsiveness of these cells was identical to that of peripheral blood neutrophils, indicating that cells in group B may be in the resting state. In contrast, cells in group A were not primed by these cytokines for enhanced release of O2- and released a large amount of O2- spontaneously, indicating that cells in group A may be in the activated state. These findings indicate that mature neutrophils with normal functions were expanded ex vivo in group B and suggest that these cells could be used for possible autologous neutrophil transfusion to prevent bacterial infections during severe neutropenia after cytotoxic chemotherapy.

Antigens, CD34↗