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Biomedical subjects

T Isomura

Publications and source records attributed to T Isomura.

At least 55 records · Page 3Linked to original sources
PubMed1997

Left ventriculoplasty: a new option for end-stage cardiomyopathy.

To treat end-stage dilated cardiomyopathy, we have performed volume reduction left ventriculoplasty (as introduced by Randas Batista in Brazil) in four patients since December 1996. All patients had end-stage idiopathic cardiomyopathy. Mitral valve replacement was also performed in three patients. In all four patients, improvement of left ventricular function was noted. One patient died of respiratory failure on the 12th postoperative day. The other three patients recovered successfully from the operation (i.e., they were discharged from hospital with the functional status in New York Heart Association Class I or II). We conclude that the Batista operation provides a real hope for patients with end-stage dilated cardiomyopathy.

Adult↗
PubMed1997

[Helical CT for lung-cancer screening: fifth report: evaluation of image quality at low-dose CT using healthy volunteers].

In order to reduce radiation dose in the application of CT for lung-cancer screening, we investigated the potential of low-dose screening helical CT (SHCT) by reducing the tube current and using an additional 10 mm aluminum filter. Six healthy volunteers were scanned at various tube currents (50 mA, 30 mA, 20 mA) with and without the filter. In comparison with the images at 50 mA without the filter, we evaluated the visualization of normal anatomical structures and the detection of simulated nodules at low-dose SHCT. Although a bias toward unclearness in the visualization of small anatomical structures was noted at 20 mA with use of the filter, no structure was assessed as having no visualization at any low-dose scan. Detection of simulated nodules was not degraded significantly by reducing the tube current to 20 mA and using the filter. Further reduction of radiation dose at SHCT may be achieved by the application of small tube current and an additional filter.

Female↗
PubMed1996

A RING finger motif regulates transforming activity of the rfp/ret fusion gene.

The rfp/ret transforming gene was generated by DNA rearrangement which occurred during transfection of NIH 3T3 cells. The amino-terminal half of Rfp with a RING finger motif was fused to the truncated Ret receptor tyrosine kinase, leading to a transforming sequence, Rfp/Ret. In the present study, to elucidate the importance of a RING finger motif for its transforming activity, we mutated cysteine or histidine residues present in the motif that are believed to be crucial for the tertiary structure of the protein. Substitution of Cys-16, Cys-31, or His-33 markedly decreased the transforming activity of Rfp/Ret. These mutations also resulted in a striking decrease of tyrosine phosphorylation of the mutant proteins in transfectants. In contrast, mutations of Cys-118 or His-124 in the second cysteine/histidine-rich motif (called B box) of Rfp/Ret did not affect its activity. These results thus indicated that the RING finger structure is critical for the full transforming activity of Rfp/Ret.

3T3 Cells↗
PubMed1996

Effect of the addition of albumin to crystalloid cardioplegic solutions on myocardial metabolism in infants undergoing open heart surgery.

The effect of the addition of albumin to crystalloid cardioplegic solutions was investigated in infants who underwent open heart surgery. The patients were divided into four groups according to whether or not they received a composition of crystalloid cardioplegic solutions containing albumin. Cardioplegic solution (Kurume solution) without albumin was administered to 12 patients (group 1); Kurume solution with 1% albumin to 10 patients (group 2); GIK solution without albumin to 10 patients (group 3); and GIK solution with 1% albumin to 15 patients (group 4). All patients had a ventricular septal defect and underwent closure of the defect with Dacron double velours through either the tricuspid or pulmonary valve. Our results showed that the percent oxygen extraction in group 2 was significantly greater than that in group 1, while the value in group 4 was less than that in group 3 at 5 min after reperfusion. No significant differences were seen between groups 1 and 2, or between groups 3 and 4, regarding the value for creatine kinase muscle-brain (MB) for any measurements during reperfusion. However, regarding the percent lactate and the malondialdehyde extraction values, significant differences between the groups with and without albumin were noted 5 min after reperfusion. These results did not completely support the addition of albumin to crystalloid cardioplegic solutions to help preserve myocardial aerobic metabolism in infants; however, such an addition might contribute to the preservation of myocardial lactate utilization while also helping to inhibit lipoperoxide metabolism immediately after reperfusion.

Cardioplegic Solutions↗
PubMed1996

Intermediate clinical results of combined gastroepiploic and internal thoracic artery bypass.

BACKGROUND: To improve the postoperative results of coronary artery bypass grafting (CABG), the internal thoracic artery (ITA) has become the conduit of choice, with a low operative risk. The gastroepiploic artery as a third arterial conduit for grafting was first reported in 1987, and the early results were reported to be as good as those for the ITA graft. In this report, we present the intermediate-term results of combining ITA and gastroepiploic artery grafts up to 7 years after the operation. METHODS: Between April 1988 and April 1992, 214 patients received CABG with at least one ITA graft and were followed up for more than 3 years. They were divided into two groups: Group I consisted of 155 patients who had CABG using one ITA with or without saphenous vein grafts, and group II consisted of 59 patients who had CABG using an ITA and a gastroepiploic artery with or without saphenous vein grafts. The duration of follow-up for hospital survivors ranged from 36 to 89 months. RESULTS: There were six late cardiac deaths in group I and one in group II. Fifteen patients complained of recurrent symptoms of angina: 13 in group I and 2 in group II. The actuarial survival rate excluding noncardiac deaths was 95.9% in group I and 96.8% in group II at 7 years (p = not significant). The cardiac event-free rate was 75.4% in group I and 92.2% in group II, which was a significant difference (p < 0.05). CONCLUSIONS: When using both the ITA and gastroepiploic artery, CABG can be performed with minimal operative risk and seems to offer an improved quality of life at least 7 years postoperatively.

Adolescent↗
PubMed1996

Mitral valve repair for mitral regurgitation with ventricular septal defect in children.

BACKGROUND: We examined the results of intermediate and long-term follow-up of 25 patients aged 3 months to 11 years (mean, 2.6 +/- 2.3 years) who initially underwent conservative mitral valve repair for mitral regurgitation associated with ventricular septal defect between April 1973 and March 1991. METHODS: The preoperative degree of mitral regurgitation was 2+ in 3, 3+ in 17, and 4+ in 5 patients, and the major causes of mitral regurgitation were annular dilatation and prolapse of the anterior leaflet. Annuloplasty was performed in all except 2 patients, suturing of the cleft was done in 3 patients, and posterior mitral leaflet advancement was done in 2 patients. In addition, the papillary muscle was incised and adhesive chordae were removed in 1 patient, and adhesive fused chordae were detached from a leaflet in 1 other patient. RESULTS: There were no early deaths. Two patients with residual mitral regurgitation with or without mitral stenosis underwent reoperation for mitral valve replacement 2 months and 6 years after the mitral repair, respectively. Late death occurred in 2 patients, and the actuarial survival rate was 92.0% at 15 years after operation. The freedom from reoperation was 91.3% at both 10 and 15 years after the initial operation. Postoperative color Doppler flow imaging was performed in 22 of the 23 survivors, and results showed no mitral regurgitation in 4, mild regurgitation in 14, and moderate regurgitation in 4 patients. Four patients presently have mitral stenosis, with a mean transmitral pressure gradient greater than 10 mm Hg. The residual lesion of moderate mitral regurgitation with or without mitral stenosis developed in 6 of 11 patients in whom bilateral mitral annuloplasty was applied after the initial operation. Nineteen of the 22 survivors without reoperation were in New York Heart Association class I, and 3 were in class II. CONCLUSIONS: Clinical improvement was observed after conservative mitral repair in most pediatric patients with ventricular septal defect. However, careful follow-up for growth potential still appears to be needed to detect changes in mitral regurgitation and the development of mitral stenosis after valve repair, especially after bilateral annuloplasty.

Child↗
PubMed1996

Postoperative changes in myosin light chain and comparison with postoperative clinical variables in patients who have undergone valve surgery.

We measured the levels of creatine kinase-MB (CK-MB) and myosin light chain (MLCI) in 86 patients after double valve replacement to investigate whether measurement of the postoperative changes in myosin could be useful in patients undergoing valve surgery. In particular, we compared the postoperative levels of CK-MB and MLCI with the occurrence of postoperative low cardiac output syndrome (LOS). In both groups of patients (group I: without LOS, group II: with LOS), the peak CK-MB level was observed on postoperative day 1, and the peak myosin level on postoperative day 5. No significant differences were found in the postoperative levels of CK-MB between the two groups. On the other hand, a significant difference in the levels of MLCI on postoperative day 5 was observed (p < 0.05). Our results also showed that the peak level of CK-MB significantly correlated with the cardiopulmonary bypass time (r = 0.50), while the peak level of MLCI was significantly correlated with the postoperative cardiac index (r = -0.45). Our retrospective findings suggest that postoperative measurement of MLCI may be useful for estimating the postoperative myocardial impairment after valve surgery.

Aortic Valve↗
PubMed1996

[Surgery for aortic valvular disease with congenital quadricuspid aortic valve].

A case of quadricuspid aortic valve is reported. A 69-year-old man was hospitalized with chest oppression at rest and abnormal electrocardiogram and diagnosed aortic regurgitation by echocardiography and aortic angiography. Aortic regurgitation was grade III according to Seller. Aortic valve replacement was performed successfully with a 21 mm St. Jude Medical valve. The aortic valve showed four cusps consisting of two equal larger cusps and two equal smaller cusps which was type C according to Hurwitz. Each valve was thickened and adhered, and fenestrations were found at each commissure. The right coronary ostium was small but not displaced. Twenty five cases in literature which were corrected surgically are also reviewed. Quadricuspid aortic valve is a rare anomaly but must be considered as a malformation which leads to severe valve failure in later life.

Aged↗
PubMed1996

[Fundamental study of lung-cancer screening by helical CT: second report: evaluation of CT images using normal volunteers].

In order to examine the use of helical computed tomography (CT) in lung cancer screening, we evaluated the effects of tube current and table feed speed on image quality. CT images of normal volunteers, which were scanned under various tube currents (150mA, 100mA, 50mA) and various table feed speeds (15mm/sec, 20mm/sec, 25mm/sec, 30mm/sec), were visually evaluated by experienced diagnostic radiologists. The images were not affected by decreasing the milliamperage. However, as table feed speed increased, images were evaluated as significantly worse. Particularly, since the degradation of the images scanned at greater than 25mm/sec was remarkable, they were judged to be unacceptable for detection of the abnormality. In conclusion, a tube current of less than 50mA and table feed speed of less than 20mm/sec are suitable in the application of helical CT for lung cancer screening.

Adult↗
PubMed1996

[Helical CT for lung-cancer screening: fourth report. Detectability of pulmonary lesions].

The detectability of various abnormal findings in helical screening CT(HSCT) with low-dose and single-breath-hold scanning of the lung was examined using conventional CT as a gold standard. In 75 patients, HSCT was obtained with scanning parameters of 120kVp, 50 mA, 10 mm-collimation. 20 mm/second and 1 sec/rotation. Conventional CT was obtained with 150 mA and 10 mm-slice contiguous scanning HSCT depicted 141 of 159 focal lesions in nodules and masses (65 of 69 lesions more than 5mm in size), 44 of 47 in infiltrative lesions, 11 of 11 in reticular lesions and 23 of 39 in bullae and blebs. There were only 3 false positive lesions in nodule and mass. Sensitivity, specificity and accuracy of HSCT for diffuse lesions were 100% (11/11), 95% (61/64) and 96% (72/75) for fibrotic change and 75% (9/12), 100% (63/63) and 96% (72/75) for emphysematous change, respectively. Since the detectability of HSCT was good for abnormal findings, showing increased attenuation in comparison with the lung parenchyma, it was considered to be a promising method for lung-cancer screening.

Adult↗
PubMed1995

Changes in the mononuclear cell subpopulations of rat cardiac transplant recipients administered FK506 for the treatment of ongoing rejection.

The inhibitory effect of ongoing rejection and the changes that occurred in mononuclear cell subpopulations were compared between four groups of rats treated with FK506 or steroids. Group 1 was given no immunosuppressive drugs, group 2 was given FK506 from the day of grafting, group 3 was commenced on FK506 on the 4th day after grafting, and group 4 was commenced on methylprednisolone (MP) on the 4th day after grafting. The graft survival times in groups 2 and 3 were significantly longer than those in groups 1 and 4, and there were fewer CD3+ and CD4+ T lymphocytes in the peripheral blood in the groups treated with immunosuppressive drugs than in group 1. In group 4, the levels in both the peripheral blood and thymus were significantly lower than those in the groups treated with FK506 despite the fact that graft rejection occurred soon after the discontinuation of steroid administration. Moreover, the levels of interleukin-2 receptors and macrophages in groups 2, 3, and 4 were significantly lower than that in group 1 postoperatively; however, the number of macrophages in groups 2 and 3 was significantly lower than that in group 4 on the 10th day after transplantation. The findings of this study demonstrated that FK506, even if administered after rejection has begun, might inhibit the subsequent extensive allograft rejection more specifically and effectively than steroids, and that the measurement of a marker for macrophages in the peripheral blood could be useful for the detection of rejection following allograft transplantation in rats.

Animals↗
PubMed1995

Fluorodeoxyglucose positron emission tomography in pancreatic cancer: an unsolved problem.

The aim of this study was to examine the significance and problems of 2-[fluorine-18]-2-deoxy-d-glucose (FDG) positron emission tomography (PET) in diagnosing pancreatic cancer and mass-forming pancreatitis (MFP). PET, X-ray computed tomography (CT) and magnetic resonance (MR) imaging were performed in 15 patients with pancreatic cancer and nine patients with MFP. The areas of the PET scan were determined according to the markers drawn on the patients at CT or MR imaging. Regions of interests (ROIs) were placed by reference to the CT or MR images corresponding to the PET images. Tissue metabolism was evaluated by the differential absorption ratio (DAR) at 50 min after intravenous injection of FDG [DAR = tissue tracer concentration/(injected dose/body weight). The DAR value differed significantly in pancreatic cancer (mean +/- SD, 4.64 +/- 1.94) and MFP (mean +/- SD, 2.84 +/- 2.22) (P < 0.05). In one false-negative case (mucinous adenocarcinoma), the tumour contained a small number of malignant cells. In one false-positive case, lymphocytes accumulated densely in the mass in the pancreatic head. Further studies are necessary to investigate the histopathological characteristics (especially the cellularity) and other factors affecting the FDG DAR on PET images.

Adenocarcinoma↗
PubMed1995

Interrupted warm blood cardioplegia for coronary artery bypass grafting.

Continuous warm blood cardioplegia has been used with good clinical outcome in both antegrade and retrograde delivery. However, the continuous delivery of cardioplegia is sometimes interrupted for adequate visualization and flow is not constant with heart manipulation during operation. We studied the effects of interrupted antegrade delivery of warm blood cardioplegia on myocardial metabolism and clinical results after surgery. Fifty-five patients undergoing isolated coronary bypass surgery received warm blood cardioplegia (n = 29) or cold crystalloid cardioplegia (n = 26) in an antegrade fashion. During reperfusion, myocardial oxygen consumption, lactate extraction, creatinine kinase isoenzyme (CK-MB), and malondialdehyde (MDA) were measured. Post-operatively, serum CK-MB and cardiac output (CO) were determined over a period of time. Myocardial oxygen extraction in the warm group was significantly greater than in the cold group 1 min after reperfusion (P < 0.02). The results revealed a tendency for patients in the warm group to have prior lactate extraction, although the difference did not reach statistic difference (P < 0.10). After removal of the aortic cross-clamp, the heart returned to sinus rhythm spontaneously in 90% of the patients with warm cardioplegia and 15.4% of those with a cold heart (P < 0.01). Postoperatively, there was no significant CK-MB or MDA release in either group except for one patient with perioperative myocardial infarction. After operation inotropic support was required for two and one patient in the warm and cold groups, respectively, although there were significantly more patients with poor left ventricular function in the warm, than in the cold, group (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗