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Biomedical subjects

T Akagi

Publications and source records attributed to T Akagi.

388 records · Page 22Linked to original sources
PubMedDate not supplied

Interventions in Kawasaki disease.

During the past 10 years, the clinical experience of catheter interventional treatment in Kawasaki disease has gradually increased. These treatments include balloon angioplasty, stent implantation, rotational ablation, and transluminal coronary revascularization. Because coronary artery stenosis in Kawasaki disease commonly involves severe calcification, in contrast with adult atherosclerotic coronary artery lesions, the indication or technique of catheter intervention for adult patients cannot be directly determined. Satisfactory acute results for coronary balloon angioplasty were obtained in patients in a relatively short interval from the onset of disease, especially within 6 years. However, the incidence of restenosis after angioplasty was still high. Rotational ablation may be the most appropriate catheter intervention for Kawasaki disease. The advantage of rotational ablation is the high success rate, even in patients with calcified coronary artery stenosis. Stent implantation requires larger arterial access and is not possible in younger children. Care should be paid to the detection of new aneurysm formation because this was associated with the use of additional balloon angioplasty using high-pressure balloon inflation. Anticoagulation or antiplatelet regimens are essential for long-term management.

Angioplasty, Balloon, Coronary↗
PubMedDate not supplied

Quantitation of the global right ventricular function in children with normal heart and congenital heart disease: a right ventricular myocardial performance index.

Although the assessment of right ventricular (RV) function is important in the clinical management of children with congenital heart disease, available imaging techniques have been limited because of the complex geometry of the right ventricle. A new Doppler index combining systolic and diastolic time intervals (the Tei index) has been reported to be useful for the assessment of global RV function in adults. However, normal values in children, age-related changes, and the clinical utility of the Tei index with regard to congenital heart disease have not been demonstrated. The purpose of this study was to prospectively assess RV function in children with normal heart and congenital heart disease using the Tei index. The subjects included 150 healthy children and 43 patients with congenital heart disease (35 patients with atrial septal defects and 8 patients who had had a Senning operation). The index was defined as the sum of isovolumetric contraction time and isovolumetric relaxation time divided by ejection time and was measured from conventional RV outflow and inflow Doppler velocity profiles. The Tei index was not affected by age in healthy children (0.24 +/- 0.04). There was a significant difference in index rating between patients who had had a Senning operation (0.58 +/- 0.09) and healthy children (p < 0.01), but there was no significant difference between children with atrial septal defect (0.25 +/- 0.13) and healthy children. The Tei index is a feasible approach to use when assessing global RV function in children with congenital heart disease.

Adolescent↗
PubMedDate not supplied

Balloon dilatation of the pulmonary valve in a patient with pulmonary atresia and intact ventricular septum using a commercially available radiofrequency catheter.

Using a commercially available 5F deflectable radiofrequency catheter, we have succeeded in percutaneous valvotomy of an imperforate pulmonary valve and consecutive balloon dilatation in a baby with pulmonary atresia and intact ventricular septum. After the procedure, right ventricular systolic pressure fell from 125 mmHg to 65 mmHg, and right ventriculography demonstrated anterograde blood flow into the pulmonary arteries. There were no major complications. Doppler echocardiography at 1 year after the procedure demonstrated a pressure gradient across the pulmonary valve of 20 mmHg with mild pulmonary and tricuspid regurgitations.

Catheter Ablation↗
PubMedDate not supplied

Successful embolization of coronary arteriovenous fistula using an interlocking detachable coil.

Although the efficacy and feasibility of coil embolization of coronary arteriovenous fistulas have been reported, the procedure may be complicated by migration of the coil into peripheral vessels or pulmonary arteries. We report two cases of successful coil embolization of such lesions using an interlocking detachable coil. This system can provide safer and more effective coil embolization in patients with coronary arteriovenous fistula.

Arteriovenous Fistula↗
PubMedDate not supplied

Carotid artery approach to balloon aortic valvuloplasty in infants with critical aortic valve stenosis.

We compare the clinical efficacy of two approaches for balloon aortic valvuloplasty (BAV) in infants with critical aortic valve stenosis. The approaches were through the carotid artery and the femoral artery. Eight catheterizations for BAV were performed in seven consecutive patients with critical aortic stenosis: four BAVs were approached through the femoral artery and four through the right common carotid artery. We inserted a 5F sheath into the right common carotid artery by a cutdown procedure; after BAV the sheath was removed and the carotid arteriotomy sutured with 7-0 monofilament. Two cases in which the femoral artery approach was used resulted in failure to perform BAV; two cases had complications. All four cases with the carotid artery approach were successful, with no complications; aortography performed 3 months after one balloon valvuloplasty revealed a smooth, unobstructed right carotid artery. Use of the carotid artery approach may reduce serious complications with BAV and offers quicker, easier maneuvering in infants and neonates with critical aortic valve stenosis.

Aortic Valve Stenosis↗
PubMedDate not supplied

Evaluation of biological responses to polymeric biomaterials by RT-PCR analysis III: study of HSP 70, 90 and 47 mRNA expression.

In this study, in order to analyze how cells recognize biomaterials, mRNA was evaluated on various substrates as shown in the attached HeLa S3 cells. The expressed Heat-Shock Protein (HSP) 70A, 70B, 90 and 47 mRNA were isolated and detected using the RT-PCR method. As a result, 70B, 90 and 47 mRNA expressions varied with differences in the hydrophilicity hydrophobicity of the substrates. HSP mRNAs outcome was induced significantly in the HeLa S3 cells that had adhered onto the hydrophilic surfaces. On the other hand, in the cells that had adhered to the hydrophobic surfaces, HSP mRNAs expressions were low. In the non-adhered HeLa S3 cells the tendency found in HSP 70B and HSP 47 mRNA's expressions was the same as that found in adhered cells, while there were no significant differences in the HSP 90 mRNA expression among either of the samples. We have concluded that HSP mRNAs expression is an important marker in the study of cell-polymer interactions.

Biocompatible Materials↗
PubMedDate not supplied

Binding of human leukocytes to fibronectin is augmented by an anti-CD44 mAb (TL-1) and blocked by another anti-CD44 mAb (Hermes-3) but not by anti-VLA-4/VLA-5 mAbs.

Fibronectin (FN) forms meshworks in extracellular spaces, and it plays an important role in cellular trafficking. Lymphoid cells are activated by binding to FN of the VLA-4 and VLA-5 receptors. CD44 also acts as a receptor of FN, but the mechanism and physiologic regulation of their binding are poorly understood. We have developed an anti-CD44 monoclonal antibody (mAb) (TL-1) in which lymphoid cells are activated and form homotypic cell aggregation. In this study, we found that the adhesion of CEM, HSB2, and LAD lymphoid cells to FN was augmented by TL-1 treatment and was apparently blocked by another anti-CD44 mAb (Hermes-3), but TL-1 Fab' fragments treatment did not induce FN-binding. A similar phenomenon is reported in the binding of the CD44 molecule to HA. This augmentation was not inhibited by the CS1 and RGD peptides of FN or by anti-VLA-4 and -VLA-5 mAbs; it was energy-dependent and associated with cytoplasmic actin filaments. Tl-1 treatment did not alter the cell surface expression of CD44 molecules. These findings above suggested that activated and/or altered cell surface distribution of CD44 molecules via a conformational change augmented the avidity of its binding to FN, which may be similar to lymphocyte-hyaluronate and lymphocyte-endothelial cell binding. As the Hermes-3 binding site is also involved in the interaction between lymphocytes and endothelial cells, activation of lymphocytes via CD44 molecules may facilitate the binding of lymphocytes to endothelial cells, extravasation, and migration to inflammatory sites rich in FN.

Adjuvants, Immunologic↗
PubMedDate not supplied

Overexpression of manganese superoxide dismutase gene suppresses spontaneous apoptosis without a resultant alteration in in vivo growth of the mouse fibrosarcoma, FSa-II.

The relationship between spontaneous apoptosis and overexpression of manganese superoxide dismutase (MnSOD) gene was examined in vivo. The mouse fibrosarcoma cells expressing high MnSOD activities due to transfection with the human MnSOD cDNA (SOD-H), or the fibrosarcoma cells transfected with the selectable marker alone (NEO), were transplanted into immune-deficient Fox Chase SCID C.B-17/Icr-scid Jcl mice. Apoptosis in tumors was visually quantified by the in situ end-labeling method. The number of apoptotic cells in the SOD-H tumors was significantly less than that in the NEO tumors. The tumor growth time of the SOD-H tumors to grow from 34 to 500 mm3 in one-half of the mice was slightly longer than that of the NEO tumors, but the difference was not statistically significant. These results suggest that overexpression of MnSOD gene is involved in the suppression of spontaneous apoptosis, without a resultant alteration in the tumor growth.

Animals↗
PubMedDate not supplied

Down-regulation of IL-18 receptor in cancer patients: its clinical significance.

Interleukin-18 (IL-18) is a powerful inducer of interferon-gamma (IFN-gamma), a key immunoregulatory cytokine. Cellular immune responsiveness, as measured by IL-18-induced IFN-gamma production from peripheral blood mononuclear cells (PBMCs) in ELISA assay, was evaluated in 10 patients with advanced cancer and in 10 normal controls. Supernatant levels of IFN-gamma were detected at 2 hours after PBMCs culture and markedly increased thereafter in healthy volunteers. In contrast, IFN-gamma production in cancer patients was not detected during the culture period (0-72 hours). We also measured IL-18-stimulated IL-12 production in healthy volunteers and null response was observed in cancer-bearing patients. Next, we studied mRNA expressions of IL-18 receptor (IL-18R) and IFN-gamma in PBMCs in cancer patients and healthy volunteers by RT-PCR assay. Both mRNA levels of IL-18R and IFN-gamma were significantly decreased in cancer-bearing patients compared with normal controls. These results suggested that IL-18 responsiveness for IFN-gamma production in cancer-bearing patients was impaired. Using flow cytometric analysis, we studied T-cell subsets, CD3- CD56+ (NK cell), CD3+ CD45RO+ (memory T-cell), CD3+ CD95+ (Fas+ T-cell), CD3+ CD4+ (helper T-cell), CD3+ CD8+ (cytotoxic T-cell: CTL) and CD3+ V alpha24+ (NKT-cell), in cancer patients and normal controls. The NK and cytotoxic T-cells significantly decreased and NKT-cells had decreased tendency in cancer patients compared with normal controls. In contrast, memory T cells, Fas+ T-cells and helper T-cells were all significantly increased in cancer patients compared with normal controls. These results suggested that the underlying mechanism of impaired IL-18 responsiveness in PBMCs from cancer-bearing patients was, at least in part, ascribed to a drastic decrease of NK cells and CTL which constitutively and highly express IL-18R and also attributed to null production of IL-12 which up-regulates IL-18R.

Adult↗